Sample records for variability long-term trends
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The influence of internal climate variability on heatwave frequency trends
NASA Astrophysics Data System (ADS)
E Perkins-Kirkpatrick, S.; Fischer, E. M.; Angélil, O.; Gibson, P. B.
2017-04-01
Understanding what drives changes in heatwaves is imperative for all systems impacted by extreme heat. We examine short- (13 yr) and long-term (56 yr) heatwave frequency trends in a 21-member ensemble of a global climate model (Community Earth System Model; CESM), where each member is driven by identical anthropogenic forcings. To estimate changes dominantly due to internal climate variability, trends were calculated in the corresponding pre-industrial control run. We find that short-term trends in heatwave frequency are not robust indicators of long-term change. Additionally, we find that a lack of a long-term trend is possible, although improbable, under historical anthropogenic forcing over many regions. All long-term trends become unprecedented against internal variability when commencing in 2015 or later, and corresponding short-term trends by 2030, while the length of trend required to represent regional long-term changes is dependent on a given realization. Lastly, within ten years of a short-term decline, 95% of regional heatwave frequency trends have reverted to increases. This suggests that observed short-term changes of decreasing heatwave frequency could recover to increasing trends within the next decade. The results of this study are specific to CESM and the ‘business as usual’ scenario, and may differ under other representations of internal variability, or be less striking when a scenario with lower anthropogenic forcing is employed.
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Jiang, Chongya; Ryu, Youngryel; Fang, Hongliang; Myneni, Ranga; Claverie, Martin; Zhu, Zaichun
2017-10-01
Understanding the long-term performance of global satellite leaf area index (LAI) products is important for global change research. However, few effort has been devoted to evaluating the long-term time-series consistencies of LAI products. This study compared four long-term LAI products (GLASS, GLOBMAP, LAI3g, and TCDR) in terms of trends, interannual variabilities, and uncertainty variations from 1982 through 2011. This study also used four ancillary LAI products (GEOV1, MERIS, MODIS C5, and MODIS C6) from 2003 through 2011 to help clarify the performances of the four long-term LAI products. In general, there were marked discrepancies between the four long-term LAI products. During the pre-MODIS period (1982-1999), both linear trends and interannual variabilities of global mean LAI followed the order GLASS>LAI3g>TCDR>GLOBMAP. The GLASS linear trend and interannual variability were almost 4.5 times those of GLOBMAP. During the overlap period (2003-2011), GLASS and GLOBMAP exhibited a decreasing trend, TCDR no trend, and LAI3g an increasing trend. GEOV1, MERIS, and MODIS C6 also exhibited an increasing trend, but to a much smaller extent than that from LAI3g. During both periods, the R 2 of detrended anomalies between the four long-term LAI products was smaller than 0.4 for most regions. Interannual variabilities of the four long-term LAI products were considerably different over the two periods, and the differences followed the order GLASS>LAI3g>TCDR>GLOBMAP. Uncertainty variations quantified by a collocation error model followed the same order. Our results indicate that the four long-term LAI products were neither intraconsistent over time nor interconsistent with each other. These inconsistencies may be due to NOAA satellite orbit changes and MODIS sensor degradation. Caution should be used in the interpretation of global changes derived from the four long-term LAI products. © 2017 John Wiley & Sons Ltd.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Bishop, L.; Hill, W.J.
A method is proposed to estimate the effect of long-term variations in total ozone on the error incurred in determining a trend in total ozone due to man-made effects. When this method is applied to data from Arosa, Switzerland over the years 1932--1980, a component of the standard error of the trend estimate equal to 0.6 percent per decade is obtained. If this estimate of long-term trend variability at Arosa is not too different from global long-term trend variability, then the threshold ( +- 2 standard errors) for detecting an ozone trend in the 1970's that is outside of whatmore » could be expected from natural variation alone and hence be man-made would range from 1.35% (Reinsel et al, 1981) to 1.8%. The latter value is obtained by combining the Reinsel et al result with the result here, assuming that the error variations that both studies measure are independent and additive. Estimates for long-term trend variation over other time periods are also derived. Simulations that measure the precision of the estimate of long-term variability are reported.« less
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Trends in Streamflow Characteristics at Long-Term Gaging Stations, Hawaii
Oki, Delwyn S.
2004-01-01
The surface-water resources of Hawaii have significant cultural, aesthetic, ecologic, and economic importance. Proper management of the surface-water resources of the State requires an understanding of the long- and short-term variability in streamflow characteristics that may occur. The U.S. Geological Survey maintains a network of stream-gaging stations in Hawaii, including a number of stations with long-term streamflow records that can be used to evaluate long-term trends and short-term variability in flow characteristics. The overall objective of this study is to obtain a better understanding of long-term trends and variations in streamflow on the islands of Hawaii, Maui, Molokai, Oahu, and Kauai, where long-term stream-gaging stations exist. This study includes (1) an analysis of long-term trends in flows (both total flow and estimated base flow) at 16 stream-gaging stations, (2) a description of patterns in trends within the State, and (3) discussion of possible regional factors (including rainfall) that are related to the observed trends and variations. Results of this study indicate the following: 1. From 1913 to 2002 base flows generally decreased in streams for which data are available, and this trend is consistent with the long-term downward trend in annual rainfall over much of the State during that period. 2. Monthly mean base flows generally were above the long-term average from 1913 to the early 1940s and below average after the early 1940s to 2002, and this pattern is consistent with the detected downward trends in base flows from 1913 to 2002. 3. Long-term downward trends in base flows of streams may indicate a reduction in ground-water discharge to streams caused by a long-term decrease in ground-water storage and recharge. 4. From 1973 to 2002, trends in streamflow were spatially variable (up in some streams and down in others) and, with a few exceptions, generally were not statistically significant. 5. Short-term variability in streamflow is related to the seasons and to the EL Ni?o-Southern Oscillation phenomenon that may be partly modulated by the phase of the Pacific Decadal Oscillation. 6. At almost all of the long-term stream-gaging stations considered in this study, average total flow (and to a lesser extent average base flow) during the winter months of January to March tended to be low following El Ni?o periods and high following La Ni?a periods, and this tendency was accentuated during positive phases of the Pacific Decadal Oscillation. 7. The El Ni?o-Southern Oscillation phenomenon occurs at a relatively short time scale (a few to several years) and appears to be more strongly related to processes controlling rainfall and direct runoff than ground-water storage and base flow. Long-term downward trends in base flows of streams may indicate a reduction in ground-water storage and recharge. Because ground water provides about 99 percent of Hawaii's domestic drinking water, a reduction in ground-water storage and recharge has serious implications for drinking-water availability. In addition, reduction in stream base flows may reduce habitat availability for native stream fauna and water availability for irrigation purposes. Further study is needed to determine (1) whether the downward trends in base flows from 1913 to 2002 will continue or whether the observed pattern is part of a long-term cycle in which base flows may eventually return to levels measured during 1913 to the early 1940s, (2) the physical causes for the detected trends and variations in streamflow, and (3) whether regional climate indicators successfully can be used to predict streamflow trends and variations throughout the State. These needs for future study underscore the importance of maintaining a network of long-term-trend stream-gaging stations in Hawaii.
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Long-term Internal Variability of the Tropical Pacific Atmosphere-Ocean System
NASA Astrophysics Data System (ADS)
Hadi Bordbar, Mohammad; Martin, Thomas; Park, Wonsun; Latif, Mojib
2016-04-01
The tropical Pacific has featured some remarkable trends during the recent decades such as an unprecedented strengthening of the Trade Winds, a strong cooling of sea surface temperatures (SST) in the eastern and central part, thereby slowing global warming and strengthening the zonal SST gradient, and highly asymmetric sea level trends with an accelerated rise relative to the global average in the western and a drop in the eastern part. These trends have been linked to an anomalously strong Pacific Walker Circulation, the major zonal atmospheric overturning cell in the tropical Pacific sector, but the origin of the strengthening is controversial. Here we address the question as to whether the recent decadal trends in the tropical Pacific atmosphere-ocean system are within the range of internal variability, as simulated in long unforced integrations of global climate models. We show that the recent trends are still within the range of long-term internal decadal variability. Further, such variability strengthens in response to enhanced greenhouse gas concentrations, which may further hinder detection of anthropogenic climate signals in that region.
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Detection time for global and regional sea level trends and accelerations
NASA Astrophysics Data System (ADS)
Jordà, G.
2014-10-01
Many studies analyze trends on sea level data with the underlying purpose of finding indications of a long-term change that could be interpreted as the signature of anthropogenic climate change. The identification of a long-term trend is a signal-to-noise problem where the natural variability (the "noise") can mask the long-term trend (the "signal"). The signal-to-noise ratio depends on the magnitude of the long-term trend, on the magnitude of the natural variability, and on the length of the record, as the climate noise is larger when averaged over short time scales and becomes smaller over longer averaging periods. In this paper, we evaluate the time required to detect centennial sea level linear trends and accelerations at global and regional scales. Using model results and tide gauge observations, we find that the averaged detection time for a centennial linear trend is 87.9, 76.0, 59.3, 40.3, and 25.2 years for trends of 0.5, 1.0, 2.0, 5.0, and 10.0 mm/yr, respectively. However, in regions with large decadal variations like the Gulf Stream or the Circumpolar current, these values can increase up to a 50%. The spatial pattern of the detection time for sea level accelerations is almost identical. The main difference is that the length of the records has to be about 40-60 years longer to detect an acceleration than to detect a linear trend leading to an equivalent change after 100 years. Finally, we have used a new sea level reconstruction, which provides a more accurate representation of interannual variability for the last century in order to estimate the detection time for global mean sea level trends and accelerations. Our results suggest that the signature of natural variability in a 30 year global mean sea level record would be less than 1 mm/yr. Therefore, at least 2.2 mm/yr of the recent sea level trend estimated by altimetry cannot be attributed to natural multidecadal variability. This article was corrected on 19 NOV 2014. See the end of the full text for details.
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NASA Technical Reports Server (NTRS)
Lee, Robert Benjamin, III; Wilson, Robert S.
2003-01-01
Long-term, incoming total solar irradiance (TSI) measurement trends were validated using proxy TSI values, derived from indices of solar magnetic activity. Spacecraft active cavity radiometers (ACR) are being used to measure longterm TSI variability, which may trigger global climate changes. The TSI, typically referred to as the solar constant, was normalized to the mean earth-sun distance. Studies of spacecraft TSI data sets confirmed the existence of a 0.1 %, long-term TSI variability component within a 10-year period. The 0.1% TSI variability component is clearly present in the spacecraft data sets from the 1984-2004 time frame. Typically, three overlapping spacecraft data sets were used to validate long-term TSI variability trends. However, during the years of 1978-1984, 1989-1991, and 1993-1996, three overlapping spacecraft data sets were not available in order to validate TSI trends. The TSI was found to vary with indices of solar magnetic activity associated with recent 10-year sunspot cycles. Proxy TSI values were derived from least squares analyses of the measured TSI variability with the solar indices of 10.7-cm solar fluxes, and with limb-darked sunspot fluxes. The resulting proxy TSI values were compared to the spacecraft ACR measurements of TSI variability to detect ACR instrument degradation, which may be interpreted as TSI variability. Analyses of ACR measurements and TSI proxies are presented primarily for the 1984-2004, Earth Radiation Budget Experiment (ERBE) ACR solar monitor data set. Differences in proxy and spacecraft measurement data sets suggest the existence of another TSI variability component with an amplitude greater than or equal to 0.5 Wm-2 (0.04%), and with a cycle of 20 years or more.
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Measurements of the Solar Spectral Irradiance Variability over Solar Cycles 21 to 24
NASA Astrophysics Data System (ADS)
Woods, T. N.
2017-12-01
The solar irradiance is the primary natural energy input into Earth's atmosphere and climate system. Understanding the long-term variations of the solar spectral irradiance (SSI) over time scales of the 11-year solar activity cycle and longer is critical for most Sun-climate research topics. There are satellite measurements of the SSI since the 1970s that contribute to understanding the solar cycle variability over Solar Cycles 21 to 24. A limiting factor for the accuracy of these results is the uncertainties for the instrument degradation corrections, for which there are fairly large corrections relative to the amount of solar cycle variability at some wavelengths. A summary of these satellite SSI measurements, which are primarily in the ultraviolet and only recently in the visible and near infrared, will be presented. Examining SSI trends using a new analysis technique is helping to identify some uncorrected instrumental trends, which once applied to the SSI trends has the potential to provide more accurate solar cycle variability results. This new technique examines the SSI trends at different levels of solar activity to provide long-term trends in a SSI record, and one of the most common components of these derived long-term trends is a downward trend that we attribute to being most likely from uncorrected instrument degradation. Examples of this analysis will be presented for some of the satellite SSI measurements to demonstrate this new technique and how it has potential to improve the understanding of solar cycle variability and to clarify the uncertainties of the trends.
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NASA Astrophysics Data System (ADS)
Ancellet, G.; Gaudel, A.; Godin-Beekmann, S.
2016-12-01
Tropospheric ozone vertical profile measurements have been carried out at OHP (Observatoire de Haute Provence, 44°N, 6.7°E, 690 m) since 1991 using both UV DIAL (DIfferential Absorption Lidar) and ECC (Electrochemical Concentration Cell) ozonesondes. For the first time, ECC and lidar data measured at the same site, have been compared over a 24 year period. The comparison conducted reveals a bias between both measurement types (ECC - lidar) of the order of 0.6 ppbv. The measurements of both instruments have been however combined to decrease the impact of short-term atmospheric variability on the trend estimate. Air mass trajectories have been calculated for all the ozone observations available at OHP including ECMWF potential vorticity (PV) and humidity chnage along the trajectories. The interannual ozone variability shows a negligible trend in the mid troposphere, but a 0.36 ppbv/year significant positive ozone trend in the upper troposphere. The trends will be discussed using the variability of the meteorological parameters. Data clustering using PV and air mass trajectories is useful to identify the role of Stratosphere-Tropopshere Exchanges and long range transport of pollutants in the observed long term trends. In the lower troposphere, the interannual variability shows contrasted trends with an ozone decrease between 1998 and 2008, consistent with the NOx emission decrease, but a new period of ozone increase since 2008 which is not very well understood.
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The objective of this study is to determine the adequacy of using a relatively coarse horizontal resolution (i.e. 36 km) to simulate long-term trends of pollutant concentrations and radiation variables with the coupled WRF-CMAQ model. WRF-CMAQ simulations over the continental Uni...
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Long-term trends in height growth of jack pine in North Central Ontario
J.C.G. Goelz; T.E. Burk
1998-01-01
Although most investigations of long-term growth trends of trees involve description of radial growth of trees, investigation of height growth of dominant and codominant trees also warrants attention for two significant reasons -- the dependent variable is largely independent of stand density and it represents an index of stand productivity. Residuals from a height...
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NASA Astrophysics Data System (ADS)
Chiu, C. M.; Hamlet, A. F.
2014-12-01
Climate change is likely to impact the Great Lakes region and Midwest region via changes in Great Lakes water levels, agricultural impacts, river flooding, urban stormwater impacts, drought, water temperature, and impacts to terrestrial and aquatic ecosystems. Self-consistent and temporally homogeneous long-term data sets of precipitation and temperature over the entire Great Lakes region and Midwest regions are needed to provide inputs to hydrologic models, assess historical trends in hydroclimatic variables, and downscale global and regional-scale climate models. To support these needs a new hybrid gridded meteorological forcing dataset at 1/16 degree resolution based on data from co-op station records, the U. S Historical Climatology Network (HCN) , the Historical Canadian Climate Database (HCCD), and Precipitation Regression on Independent Slopes Method (PRISM) has been assembled over the Great Lakes and Midwest region from 1915-2012 at daily time step. These data were then used as inputs to the macro-scale Variable Infiltration Capacity (VIC) hydrology model, implemented over the Midwest and Great Lakes region at 1/16 degree resolution, to produce simulated hydrologic variables that are amenable to long-term trend analysis. Trends in precipitation and temperature from the new meteorological driving data sets, as well as simulated hydrometeorological variables such as snowpack, soil moisture, runoff, and evaporation over the 20th century are presented and discussed.
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Spring onset variations and long-term trends from new hemispheric-scale products and remote sensing
NASA Astrophysics Data System (ADS)
Dye, D. G.; Li, X.; Ault, T.; Zurita-Milla, R.; Schwartz, M. D.
2015-12-01
Spring onset is commonly characterized by plant phenophase changes among a variety of biophysical transitions and has important implications for natural and man-managed ecosystems. Here, we present a new integrated analysis of variability in gridded Northern Hemisphere spring onset metrics. We developed a set of hemispheric temperature-based spring indices spanning 1920-2013. As these were derived solely from meteorological data, they are used as a benchmark for isolating the climate system's role in modulating spring "green up" estimated from the annual cycle of normalized difference vegetation index (NDVI). Spatial patterns of interannual variations, teleconnections, and long-term trends were also analyzed in all metrics. At mid-to-high latitudes, all indices exhibit larger variability at interannual to decadal time scales than at spatial scales of a few kilometers. Trends of spring onset vary across space and time. However, compared to long-term trend, interannual to decadal variability generally accounts for a larger portion of the total variance in spring onset timing. Therefore, spring onset trends identified from short existing records may be aliased by decadal climate variations due to their limited temporal depth, even when these records span the entire satellite era. Based on our findings, we also demonstrated that our indices have skill in representing ecosystem-level spring phenology and may have important implications in understanding relationships between phenology, atmosphere dynamics and climate variability.
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USDA-ARS?s Scientific Manuscript database
Long-term research conducted at multiple scales is critical to assessing the effects of key long term drivers (e.g., global population growth; land-use change; increased competition for natural resources; climate variability and change) on our ability to sustain or enhance agricultural production to...
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Two centuries of observed atmospheric variability and change over the North Sea region
NASA Astrophysics Data System (ADS)
Stendel, Martin; van den Besselaar, Else; Hannachi, Abdel; Kent, Elizabeth; Lefebvre, Christiana; van Oldenborgh, Geert Jan; Rosenhagen, Gudrun; Schenk, Frederik; van der Schrier, Gerard
2015-04-01
Situated in northwestern Europe, the North Sea region is under influence of air masses from subtropical to arctic origin, and thus exhibits significant natural climate variability. As the land areas surrounding the North Sea are densely populated, climate change is an important issue in terms of e.g. coastal protection, fishery and trade. This study is part of the NOSCCA initiative (North Sea Region Climate Change Assessment) and presents observed variability and changes in atmospheric parameters during the last roughly 200 years. Circulation patterns show considerable decadal variability. In recent decades, a northward shift of storm tracks and increased cyclonic activity has been observed. There is also an indication of increased persistence of weather types. The wind climate is dominated by large multidecadal variability, and no robust long-term trends can be identified in the available datasets. There is a clear positive trend in near-surface temperatures, in particular during spring and winter. Over the region as a whole, no clear long-term precipitation trends are visible, although regional indications exist for an increased risk of extreme precipitation events.
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NASA Astrophysics Data System (ADS)
Antón, M.; Román, R.; Sanchez-Lorenzo, A.; Calbó, J.; Vaquero, J. M.
2017-07-01
This study focuses on the analysis of the daily global solar radiation (GSR) reconstructed from sunshine duration measurements at Madrid (Spain) from 1887 to 1950. Additionally, cloud cover information recorded simultaneously by human observations for the study period was also analyzed and used to select cloud-free days. First, the day-to-day variability of reconstructed GSR data was evaluated, finding a strong relationship between GSR and cloudiness. The second step was to analyze the long-term evolution of the GSR data which exhibited two clear trends with opposite sign: a marked negative trend of - 36 kJ/m2 per year for 1887-1915 period and a moderate positive trend of + 13 kJ/m2 per year for 1916-1950 period, both statistically significant at the 95% confidence level. Therefore, there is evidence of "early dimming" and "early brightening" periods in the reconstructed GSR data for all-sky conditions in Madrid from the late 19th to the mid-20th centuries. Unlike the long-term evolution of GSR data, cloud cover showed non-statistically significant trends for the two analyzed sub-periods, 1887-1915 and 1916-1950. Finally, GSR trends were analyzed exclusively under cloud-free conditions in summer by means of the determination of the clearness index for those days with all cloud cover observations equal to zero oktas. The long-term evolution of the clearness index was in accordance with the "early dimming" and "early brightening" periods, showing smaller trends but still statistically significant. This result points out that aerosol load variability could have had a non-negligible influence on the long-term evolution of GSR even as far as from the late 19th century.
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Hermanowski, Tomasz; Bystrov, Victor; Staszewska-Bystrova, Anna; Szafraniec-Buryło, Sylwia I; Rabczenko, Daniel; Kolasa, Katarzyna; Orlewska, Ewa
2015-01-01
Life expectancy is a common measure of population health. Macro-perspective based on aggregated data makes it possible to approximate the impact of different levels of pharmaceutical expenditure on general population health status and is often used in cross-country comparisons. The aim of the study was to determine whether there are long-run relations between life expectancy, total healthcare expenditures, and pharmaceutical expenditures in OECD countries. Common trends in per capita gross domestic products (GDPs) (excluding healthcare expenditures), per capita healthcare expenditures (excluding pharmaceutical expenditures), per capita pharmaceutical expenditures, and life expectancies of women and men aged 60 and 65 were analyzed across OECD countries. Short-term effect of pharmaceutical expenditure onto life expectancy was also estimated by regressing the deviations of life expectancies from their long-term trends onto the deviations of pharmaceutical and non-pharmaceutical health expenditures, as well as GDP from their trends. The dataset was created on the basis of OECD Health Data for 34 countries and the years 1991-2010. Life expectancy variables were used as proxies for the health outcomes, whereas the pharmaceutical and healthcare expenditures represented drug and healthcare consumption, respectively. In general, both expenditures and life expectancies tended to increase in all of the analyzed countries; however, the growth rates differed across the countries. The analysis of common trends indicated the existence of common long-term trends in life expectancies and per capita GDP as well as pharmaceutical and non-pharmaceutical healthcare expenditures. However, there was no evidence that pharmaceutical expenditures provided additional information about the long-term trends in life expectancies beyond that contained in the GDP series. The analysis based on the deviations of variables from their long-term trends allowed concluding that pharmaceutical expenditures significantly influenced life expectancies in the short run. Non-pharmaceutical healthcare expenditures were found to be significant in one out of four models (for life expectancy of women aged 65), while GDPs were found to be insignificant in all four models. The results of the study indicate that there are common long-term trends in life expectancies and per capita GDP as well as pharmaceutical and non-pharmaceutical healthcare expenditures. The available data did not reveal any cause- effect relationship. Other factors, for which the systematic data were not available, may have determined the increase in life expectancy in OECD countries. Significant positive short-term relations between pharmaceutical expenditures and life expectancies in OECD countries were found. The significant short-term effect of pharmaceutical expenditures onto life expectancy means that an increase of pharmaceutical expenditures above long-term trends would lead to a temporary increase in life expectancy above its corresponding long-term trend. However, this effect would not persist as pharmaceutical expenditures and life expectancy would converge to levels determined by the long-term trends.
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Estimating trends in the global mean temperature record
NASA Astrophysics Data System (ADS)
Poppick, Andrew; Moyer, Elisabeth J.; Stein, Michael L.
2017-06-01
Given uncertainties in physical theory and numerical climate simulations, the historical temperature record is often used as a source of empirical information about climate change. Many historical trend analyses appear to de-emphasize physical and statistical assumptions: examples include regression models that treat time rather than radiative forcing as the relevant covariate, and time series methods that account for internal variability in nonparametric rather than parametric ways. However, given a limited data record and the presence of internal variability, estimating radiatively forced temperature trends in the historical record necessarily requires some assumptions. Ostensibly empirical methods can also involve an inherent conflict in assumptions: they require data records that are short enough for naive trend models to be applicable, but long enough for long-timescale internal variability to be accounted for. In the context of global mean temperatures, empirical methods that appear to de-emphasize assumptions can therefore produce misleading inferences, because the trend over the twentieth century is complex and the scale of temporal correlation is long relative to the length of the data record. We illustrate here how a simple but physically motivated trend model can provide better-fitting and more broadly applicable trend estimates and can allow for a wider array of questions to be addressed. In particular, the model allows one to distinguish, within a single statistical framework, between uncertainties in the shorter-term vs. longer-term response to radiative forcing, with implications not only on historical trends but also on uncertainties in future projections. We also investigate the consequence on inferred uncertainties of the choice of a statistical description of internal variability. While nonparametric methods may seem to avoid making explicit assumptions, we demonstrate how even misspecified parametric statistical methods, if attuned to the important characteristics of internal variability, can result in more accurate uncertainty statements about trends.
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Human Land-Use Practices Lead to Global Long-Term Increases in Photosynthetic Capacity
NASA Technical Reports Server (NTRS)
Mueller, Thomas; Tucker, Compton J.; Dressler, Gunnar; Pinzon, Jorge E.; Leimgruber, Peter; Dubayah, Ralph O.; Hurtt, George C.; Boehning-Gaese, Katrin; Fagan, William F.
2014-01-01
Long-term trends in photosynthetic capacity measured with the satellite-derived Normalized Difference Vegetation Index (NDVI) are usually associated with climate change. Human impacts on the global land surface are typically not accounted for. Here, we provide the first global analysis quantifying the effect of the earth's human footprint on NDVI trends. Globally, more than 20% of the variability in NDVI trends was explained by anthropogenic factors such as land use, nitrogen fertilization, and irrigation. Intensely used land classes, such as villages, showed the greatest rates of increase in NDVI, more than twice than those of forests. These findings reveal that factors beyond climate influence global long-term trends in NDVI and suggest that global climate change models and analyses of primary productivity should incorporate land use effects.
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Streamflow characteristics and trends along Soldier Creek, Northeast Kansas
Juracek, Kyle E.
2017-08-16
Historical data for six selected U.S. Geological Survey streamgages along Soldier Creek in northeast Kansas were used in an assessment of streamflow characteristics and trends. This information is required by the Prairie Band Potawatomi Nation for the effective management of tribal water resources, including drought contingency planning. Streamflow data for the period of record at each streamgage were used to assess annual mean streamflow, annual mean base flow, mean monthly flow, annual peak flow, and annual minimum flow.Annual mean streamflows along Soldier Creek were characterized by substantial year-to-year variability with no pronounced long-term trends. On average, annual mean base flow accounted for about 20 percent of annual mean streamflow. Mean monthly flows followed a general seasonal pattern that included peak values in spring and low values in winter. Annual peak flows, which were characterized by considerable year-to-year variability, were most likely to occur in May and June and least likely to occur during November through February. With the exception of a weak yet statistically significant increasing trend at the Soldier Creek near Topeka, Kansas, streamgage, there were no pronounced long-term trends in annual peak flows. Annual 1-day, 30-day, and 90-day mean minimum flows were characterized by considerable year-to-year variability with no pronounced long-term trend. During an extreme drought, as was the case in the mid-1950s, there may be zero flow in Soldier Creek continuously for a period of one to several months.
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Botlaguduru, Venkata S V; Kommalapati, Raghava R; Huque, Ziaul
2018-04-19
The Houston-Galveston-Brazoria (HGB) area of Texas has a history of ozone exceedances and is currently classified under moderate nonattainment status for the 2008 8-hr ozone standard of 75 ppb. The HGB area is characterized by intense solar radiation, high temperature, and humidity, which influence day-to-day variations in ozone concentrations. Long-term air quality trends independent of meteorological influence need to be constructed for ascertaining the effectiveness of air quality management in this area. The Kolmogorov-Zurbenko (KZ) filter technique used to separate different scales of motion in a time series, is applied in the current study for maximum daily 8-hr (MDA8) ozone concentrations at an urban site (EPA AQS Site ID: 48-201-0024, Aldine) in the HGB area. This site located within 10 miles of downtown Houston and the George Bush Intercontinental Airport, was selected for developing long-term meteorologically independent MDA8 ozone trends for the years 1990-2016. Results from this study indicate a consistent decrease in meteorologically independent MDA8 ozone between 2000-2016. This pattern could be partially attributed to a reduction in underlying NO X emissions, particularly that of lowering nitrogen dioxide (NO 2 ) levels, and a decrease in the release of highly reactive volatile organic compounds (HRVOC). Results also suggest solar radiation to be most strongly correlated to ozone, with temperature being the secondary meteorological control variable. Relative humidity and wind speed have tertiary influence at this site. This study observed that meteorological variability accounts for a high of 61% variability in baseline ozone (low-frequency component, sum of long-term and seasonal components), while 64% of the change in long-term MDA8 ozone post-2000 could be attributed to NO X emissions reduction. Long-term MDA8 ozone trend component was estimated to be decreasing at a linear rate of 0.412 ± 0.007 ppb/yr for the years 2000-2016, and 0.155 ± 0.005 ppb/yr for the overall period of 1990-2016. Implications Statement The effectiveness of air emission controls can be evaluated by developing long-term air quality trends independent of meteorological influences. KZ filter technique is a well-established method to separate an air quality time-series into: short-term, seasonal and long-term components. This paper applies the KZ filter technique to MDA8 ozone data between 1990-2016 at an urban site in the Greater Houston area and estimates the variance accounted for, by the primary meteorological control variables. Estimates for linear trends of MDA8 ozone are calculated and underlying causes are investigated to provide a guidance for further investigation into air quality management of the Greater Houston Area.
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Long-term forecasting of internet backbone traffic.
Papagiannaki, Konstantina; Taft, Nina; Zhang, Zhi-Li; Diot, Christophe
2005-09-01
We introduce a methodology to predict when and where link additions/upgrades have to take place in an Internet protocol (IP) backbone network. Using simple network management protocol (SNMP) statistics, collected continuously since 1999, we compute aggregate demand between any two adjacent points of presence (PoPs) and look at its evolution at time scales larger than 1 h. We show that IP backbone traffic exhibits visible long term trends, strong periodicities, and variability at multiple time scales. Our methodology relies on the wavelet multiresolution analysis (MRA) and linear time series models. Using wavelet MRA, we smooth the collected measurements until we identify the overall long-term trend. The fluctuations around the obtained trend are further analyzed at multiple time scales. We show that the largest amount of variability in the original signal is due to its fluctuations at the 12-h time scale. We model inter-PoP aggregate demand as a multiple linear regression model, consisting of the two identified components. We show that this model accounts for 98% of the total energy in the original signal, while explaining 90% of its variance. Weekly approximations of those components can be accurately modeled with low-order autoregressive integrated moving average (ARIMA) models. We show that forecasting the long term trend and the fluctuations of the traffic at the 12-h time scale yields accurate estimates for at least 6 months in the future.
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Joint variability of global runoff and global sea surface temperatures
McCabe, G.J.; Wolock, D.M.
2008-01-01
Global land surface runoff and sea surface temperatures (SST) are analyzed to identify the primary modes of variability of these hydroclimatic data for the period 1905-2002. A monthly water-balance model first is used with global monthly temperature and precipitation data to compute time series of annual gridded runoff for the analysis period. The annual runoff time series data are combined with gridded annual sea surface temperature data, and the combined dataset is subjected to a principal components analysis (PCA) to identify the primary modes of variability. The first three components from the PCA explain 29% of the total variability in the combined runoff/SST dataset. The first component explains 15% of the total variance and primarily represents long-term trends in the data. The long-term trends in SSTs are evident as warming in all of the oceans. The associated long-term trends in runoff suggest increasing flows for parts of North America, South America, Eurasia, and Australia; decreasing runoff is most notable in western Africa. The second principal component explains 9% of the total variance and reflects variability of the El Ni??o-Southern Oscillation (ENSO) and its associated influence on global annual runoff patterns. The third component explains 5% of the total variance and indicates a response of global annual runoff to variability in North Aflantic SSTs. The association between runoff and North Atlantic SSTs may explain an apparent steplike change in runoff that occurred around 1970 for a number of continental regions.
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NASA Astrophysics Data System (ADS)
Lenters, J. D.; Read, J. S.; Sharma, S.; O'Reilly, C.; Hampton, S. E.; Gray, D.; McIntyre, P. B.; Hook, S. J.; Schneider, P.; Soylu, M. E.; Barabás, N.; Lofton, D. D.
2014-12-01
Global and regional changes in climate have important implications for terrestrial and aquatic ecosystems. Recent studies, for example, have revealed significant warming of inland water bodies throughout the world. To better understand the global patterns, physical mechanisms, and ecological implications of lake warming, an initiative known as the "Global Lake Temperature Collaboration" (GLTC) was started in 2010, with the objective of compiling and analyzing lake temperature data from numerous satellite and in situ records dating back at least 20-30 years. The GLTC project has now assembled data from over 300 lakes, with some in situ records extending back more than 100 years. Here, we present an analysis of the long-term warming trends, interdecadal variability, and a direct comparison between in situ and remotely sensed lake surface temperature for the 3-month summer period July-September (January-March for some lakes). The overall results show consistent, long-term trends of increasing summer-mean lake surface temperature across most but not all sites. Lakes with especially long records show accelerated warming in the most recent two to three decades, with almost half of the lakes warming at rates in excess of 0.5 °C per decade during the period 1985-2009, and a few even exceeding 1.0 °C per decade. Both satellite and in situ data show a similar distribution of warming trends, and a direct comparison at lake sites that have both types of data reveals a close correspondence in mean summer water temperature, interannual variability, and long-term trends. Finally, we examine standardized lake surface temperature anomalies across the full 100-year period (1910-2009), and in conjunction with similar timeseries of air temperature. The results reveal a close correspondence between summer air temperature and lake surface temperature on interannual and interdecadal timescales, but with many lakes warming more rapidly than the ambient air temperature over 25- to 100-year periods.
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Long-term Trend of Satellite-observed Chlorophyll-a Concentration Variations in the East/Japan Sea
NASA Astrophysics Data System (ADS)
Park, J. E.; PARK, K. A.
2016-02-01
Long-term time-series of satellite ocean color data enable us to analyze the effects of climate change on ocean ecosystem through chlorophyll-a concentration as a proxy for phytoplankton biomass. In this study, we constructed a 17 year-long time-series dataset (1998-2014) of chlorophyll-a concentration by combining SeaWiFS (Obrview-2, 1997-2010) and MODIS (Aqua, 2002-present) data in the East Sea (Japan Sea). Several types of errors such as anonymously high values (a speckle error), stripe-like patterns, discrepancy originating from time gap between the two satellites were eliminated to enhance the accuracy of chlorophyll-a concentration data. The composited chlorophyll-a concentration maps, passing through the post-processing of the speckle errors, were improved significantly, by 14% of abnormal variability in maximum. Using the database, we investigated spatial and temporal variability of chlorophyll-a concentration in the East Sea. Spatial distribution of long-term trend of chlorophyll-a concentration indicated obvious distinction between northern and southern regions of the subpolar front. It revealed predominant seasonal variabilities as well as long-term changes in the timings of spring bloom. This study addresses the important role of local climate change on fast changing ecosystem of the East Sea as one of miniature oceans.
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Johnson, Zackary I.; Wheeler, Benjamin J.; Blinebry, Sara K.; Carlson, Christina M.; Ward, Christopher S.; Hunt, Dana E.
2013-01-01
Increasing atmospheric carbon dioxide (CO2) from anthropogenic sources is acidifying marine environments resulting in potentially dramatic consequences for the physical, chemical and biological functioning of these ecosystems. If current trends continue, mean ocean pH is expected to decrease by ~0.2 units over the next ~50 years. Yet, there is also substantial temporal variability in pH and other carbon system parameters in the ocean resulting in regions that already experience change that exceeds long-term projected trends in pH. This points to short-term dynamics as an important layer of complexity on top of long-term trends. Thus, in order to predict future climate change impacts, there is a critical need to characterize the natural range and dynamics of the marine carbonate system and the mechanisms responsible for observed variability. Here, we present pH and dissolved inorganic carbon (DIC) at time intervals spanning 1 hour to >1 year from a dynamic, coastal, temperate marine system (Beaufort Inlet, Beaufort NC USA) to characterize the carbonate system at multiple time scales. Daily and seasonal variation of the carbonate system is largely driven by temperature, alkalinity and the balance between primary production and respiration, but high frequency change (hours to days) is further influenced by water mass movement (e.g. tides) and stochastic events (e.g. storms). Both annual (~0.3 units) and diurnal (~0.1 units) variability in coastal ocean acidity are similar in magnitude to 50 year projections of ocean acidity associated with increasing atmospheric CO2. The environmental variables driving these changes highlight the importance of characterizing the complete carbonate system rather than just pH. Short-term dynamics of ocean carbon parameters may already exert significant pressure on some coastal marine ecosystems with implications for ecology, biogeochemistry and evolution and this shorter term variability layers additive effects and complexity, including extreme values, on top of long-term trends in ocean acidification. PMID:24358377
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Long term trend and interannual variability of land carbon uptake — the attribution and processes
NASA Astrophysics Data System (ADS)
Fu, Zheng
2017-04-01
Ecosystem carbon (C) uptake in terrestrial ecosystems has increased over the past five decades, but with large interannual variability (IAV). However, we are not clear on the attribution and the processes that control the long-term trend and IAV of land C uptake. Using atmospheric inversion net ecosystem exchange (NEE) data, we quantified the trend and IAV of NEE across the globe, the Northern Hemisphere (NH), and the Southern Hemisphere (SH), and decomposed NEE into carbon uptake amplitude and duration during each year from 1979-2013. We found the NH rather than the SH determined the IAV, while both hemispheres contributed equivalently to the global NEE trend. Different ecosystems in the NH and SH had differential relative contributions to their trend and IAV. The long-term trends of increased C uptake across the globe and the SH were attributed to both extended duration and increasing amplitude of C uptake. The shortened duration of uptake in the NH partly offsets the effects of increased NEE amplitude, making the net C uptake trend the same as that of the SH. The change in NEE IAV was also linked to changes in the amplitude and duration of uptake, but they worked in different ways in the NH, SH and globe. The fundamental attributions of amplitude and duration of C uptake revealed in this study are helpful to better understand the mechanisms underlying the trend and IAV of land C uptake. Our findings also suggest the critical roles of grassland and croplands in the NH in contributing to the trend and IAV of land C uptake.
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Long term trend and interannual variability of land carbon uptake—the attribution and processes
NASA Astrophysics Data System (ADS)
Fu, Zheng; Dong, Jinwei; Zhou, Yuke; Stoy, Paul C.; Niu, Shuli
2017-01-01
Ecosystem carbon (C) uptake in terrestrial ecosystems has increased over the past five decades, but with large interannual variability (IAV). However, we are not clear on the attribution and the processes that control the long-term trend and IAV of land C uptake. Using atmospheric inversion net ecosystem exchange (NEE) data, we quantified the trend and IAV of NEE across the globe, the Northern Hemisphere (NH), and the Southern Hemisphere (SH), and decomposed NEE into carbon uptake amplitude and duration during each year from 1979-2013. We found the NH rather than the SH determined the IAV, while both hemispheres contributed equivalently to the global NEE trend. Different ecosystems in the NH and SH had differential relative contributions to their trend and IAV. The long-term trends of increased C uptake across the globe and the SH were attributed to both extended duration and increasing amplitude of C uptake. The shortened duration of uptake in the NH partly offsets the effects of increased NEE amplitude, making the net C uptake trend the same as that of the SH. The change in NEE IAV was also linked to changes in the amplitude and duration of uptake, but they worked in different ways in the NH, SH and globe. The fundamental attributions of amplitude and duration of C uptake revealed in this study are helpful to better understand the mechanisms underlying the trend and IAV of land C uptake. Our findings also suggest the critical roles of grassland and croplands in the NH in contributing to the trend and IAV of land C uptake.
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Analyzing the Effects of Horizontal Resolution on Long-Term Coupled WRF-CMAQ Simulations
The objective of this study is to determine the adequacy of using a relatively coarse horizontal resolution (i.e. 36 km) to simulate long-term trends of pollutant concentrations and radiation variables with the coupled WRF-CMAQ model. To this end, WRF-CMAQ simulations over the co...
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Global long-term ozone trends derived from different observed and modelled data sets
NASA Astrophysics Data System (ADS)
Coldewey-Egbers, M.; Loyola, D.; Zimmer, W.; van Roozendael, M.; Lerot, C.; Dameris, M.; Garny, H.; Braesicke, P.; Koukouli, M.; Balis, D.
2012-04-01
The long-term behaviour of stratospheric ozone amounts during the past three decades is investigated on a global scale using different observed and modelled data sets. Three European satellite sensors GOME/ERS-2, SCIAMACHY/ENVISAT, and GOME-2/METOP are combined and a merged global monthly mean total ozone product has been prepared using an inter-satellite calibration approach. The data set covers the 16-years period from June 1995 to June 2011 and it exhibits an excellent long-term stability, which is required for such trend studies. A multiple linear least-squares regression algorithm using different explanatory variables is applied to the time series and statistically significant positive trends are detected in the northern mid latitudes and subtropics. Global trends are also estimated using a second satellite-based Merged Ozone Data set (MOD) provided by NASA. For few selected geographical regions ozone trends are additionally calculated using well-maintained measurements of individual Dobson/Brewer ground-based instruments. A reasonable agreement in the spatial patterns of the trends is found amongst the European satellite, the NASA satellite, and the ground-based observations. Furthermore, two long-term simulations obtained with the Chemistry-Climate Models E39C-A provided by German Aerospace Center and UMUKCA-UCAM provided by University of Cambridge are analysed.
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NASA Astrophysics Data System (ADS)
Kukal, M.; Irmak, S.
2016-11-01
Detection of long-term changes in climate variables over large spatial scales is a very important prerequisite to the development of effective mitigation and adaptation measures for the future potential climate change and for developing strategies for future hydrologic balance analyses under changing climate. Moreover, there is a need for effective approaches of providing information about these changes to decision makers, water managers and stakeholders to aid in efficient implementation of the developed strategies. This study involves computation, mapping and analyses of long-term (1968-2013) county-specific trends in annual, growing-season (1st May-30th September) and monthly air temperatures [(maximum (Tmax), minimum (Tmin) and average (Tavg)], daily temperature range (DTR), precipitation, grass reference evapotranspiration (ETo) and aridity index (AI) over the USA Great Plains region using datasets from over 800 weather station sites. Positive trends in annual Tavg, Tmax and Tmin, DTR, precipitation, ETo and AI were observed in 71%, 89%, 85%, 31%, 61%, 38% and 66% of the counties in the region, respectively, whereas these proportions were 48%, 89%, 62%, 20%, 57%, 28%, and 63%, respectively, for the growing-season averages of the same variables. On a regional average basis, the positive trends in growing-season Tavg, Tmax and Tmin, DTR, precipitation, ETo and AI were 0.18 °C decade-1, 0.19 °C decade-1, 0.17 °C decade-1, 0.09 °C decade-1, 1.12 mm yr-1, 0.4 mm yr-1 and 0.02 decade-1, respectively, and the negative trends were 0.21 °C decade-1, 0.06 °C decade-1, 0.09 °C decade-1, 0.22 °C decade-1, 1.16 mm yr-1, 0.76 mm yr-1 and 0.02 decade-1, respectively. The temporal trends were highly variable in space and were appropriately represented using monthly, annual and growing-season maps developed using Geographic Information System (GIS) techniques. The long-term and spatial and temporal information and data for a large region provided in this study can be used to analyze county-level trends in important climatic/hydrologic variables in context of climate change, water resources, agricultural and natural resources response to climate change.
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Role of internal variability in recent decadal to multidecadal tropical Pacific climate changes
NASA Astrophysics Data System (ADS)
Bordbar, Mohammad Hadi; Martin, Thomas; Latif, Mojib; Park, Wonsun
2017-05-01
While the Earth's surface has considerably warmed over the past two decades, the tropical Pacific has featured a cooling of sea surface temperatures in its eastern and central parts, which went along with an unprecedented strengthening of the equatorial trade winds, the surface component of the Pacific Walker Circulation (PWC). Previous studies show that this decadal trend in the trade winds is generally beyond the range of decadal trends simulated by climate models when forced by historical radiative forcing. There is still a debate on the origin of and the potential role that internal variability may have played in the recent decadal surface wind trend. Using a number of long control (unforced) integrations of global climate models and several observational data sets, we address the question as to whether the recent decadal to multidecadal trends are robustly classified as an unusual event or the persistent response to external forcing. The observed trends in the tropical Pacific surface climate are still within the range of the long-term internal variability spanned by the models but represent an extreme realization of this variability. Thus, the recent observed decadal trends in the tropical Pacific, though highly unusual, could be of natural origin. We note that the long-term trends in the selected PWC indices exhibit a large observational uncertainty, even hindering definitive statements about the sign of the trends.
Plain Language SummaryWhile the Earth's surface has considerably warmed over the past two decades, the tropical Pacific has featured a cooling of sea surface temperatures in its eastern and central parts, which went along with an unprecedented strengthening of the equatorial trade winds. Here we show that climate models simulate a high level of internal variability, so that the recent changes in the tropical Pacific could still be due to natural processes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRD..121.3519L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRD..121.3519L"><span>The long-term trend in the diurnal temperature range over Asia and its natural and anthropogenic causes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Lin; Li, Zhanqing; Yang, Xin; Gong, Hainan; Li, Chao; Xiong, Anyuan</p> <p>2016-04-01</p> <p>Understanding the causes of long-term temperature trends is at the core of climate change studies. Any observed trend can result from natural variability or anthropogenic influences or both. In the present study, we evaluated the performance of 18 climate models from the Coupled Model Intercomparison Project Phase 5 on simulating the Asian diurnal temperature range (DTR) and explored the potential causes of the long-term trend in the DTR by examining the response of the DTR to natural forcing (volcanic aerosols and solar variability) and anthropogenic forcing (anthropogenic greenhouse gases (GHG) and aerosols) in the historical period of 1961-2005. For the climatology, the multimodel ensemble mean reproduced the geographical distribution and amplitude of the DTR over eastern China and India but underestimated the magnitudes of the DTR over the Tibetan Plateau and the high-latitude regions of the Asian continent. These negative biases in the DTR over frigid zones existed in most models. Seasonal biases in the DTR pattern from models were similar to the bias in the annual mean DTR pattern. Based on three selected state-of-the-art models, the observed decreasing trend in the DTR over Asia was reasonably reproduced in the all-forcing run. A comparison of separate forcing experiments revealed that anthropogenic forcing plays the dominant role in the declining trend in the DTR. Observations and model simulations showed that GHG forcing is mainly responsible for the negative trends in the DTR over Asia but that anthropogenic aerosol forcing was also behind the decreasing trend in the DTR over China and especially over eastern China.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A53D2273F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A53D2273F"><span>A new record of Atlantic sea surface salinity from 1896-2013 reveals the signatures of climate variability and long-term trends</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Friedman, A. R.; Reverdin, G. P.; Khodri, M.; Gastineau, G.</p> <p>2017-12-01</p> <p>In the North Atlantic, sea surface salinity is both an indicator of the hydrological cycle and an active component of the ocean circulation. As an indirect "ocean rain gauge", surface salinity reflects the net surface fluxes of evaporation - precipitation + runoff, along with advection and vertical mixing. Subpolar surface salinity also may influence the strength of deep convection and the Atlantic Meridional Overturning Circulation (AMOC). However, continuous surface salinity time series beginning before the 1950s are rare, limiting our ability to resolve modes of variability and long-term trends. Here, we present a new gridded surface salinity record in the Atlantic from 1896-2013, compiled from a variety of historical sources. The compilation covers most of the Atlantic from 20°S-70°N, at 100-1000 km length scale and interannual temporal resolution, allowing us to resolve major modes of variability and linkages with large-scale Atlantic climate variations. We find that the low-latitude (tropical and subtropical) Atlantic and the subpolar Atlantic surface salinity are negatively correlated, with subpolar anomalies leading low-latitude anomalies by about a decade. Subpolar surface salinity varies in phase with the Atlantic Multidecadal Oscillation (AMO), whereas low-latitude surface salinity lags the AMO and varies in phase with the low-frequency North Atlantic Oscillation (NAO). Additionally, northern tropical surface salinity is anticorrelated with the AMO and with Sahel rainfall, suggesting that it reflects the latitude of the Intertropical Convergence Zone. The 1896-2013 long-term trend features an amplification of the mean Atlantic surface salinity gradient pattern, with freshening in the subpolar Atlantic and salinification in the tropical and subtropical Atlantic. We find that regressing out the AMO and the low-frequency NAO has little effect on the long-term residual trend. The spatial trend structure is consistent with the "rich-get-richer" hydrological cycle intensification response to global warming, and may also indicate increased Arctic cryosphere melting and surface runoff.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRD..122.7119B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRD..122.7119B"><span>An intercomparison of multidecadal observational and reanalysis data sets for global total ozone trends and variability analysis</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bai, Kaixu; Chang, Ni-Bin; Shi, Runhe; Yu, Huijia; Gao, Wei</p> <p>2017-07-01</p> <p>A four-step adaptive ozone trend estimation scheme is proposed by integrating multivariate linear regression (MLR) and ensemble empirical mode decomposition (EEMD) to analyze the long-term variability of total column ozone from a set of four observational and reanalysis total ozone data sets, including the rarely explored ERA-Interim total ozone reanalysis, from 1979 to 2009. Consistency among the four data sets was first assessed, indicating a mean relative difference of 1% and root-mean-square error around 2% on average, with respect to collocated ground-based total ozone observations. Nevertheless, large drifts with significant spatiotemporal inhomogeneity were diagnosed in ERA-Interim after 1995. To emphasize long-term trends, natural ozone variations associated with the solar cycle, quasi-biennial oscillation, volcanic aerosols, and El Niño-Southern Oscillation were modeled with MLR and then removed from each total ozone record, respectively, before performing EEMD analyses. The resulting rates of change estimated from the proposed scheme captured the long-term ozone variability well, with an inflection time of 2000 clearly detected. The positive rates of change after 2000 suggest that the ozone layer seems to be on a healing path, but the results are still inadequate to conclude an actual recovery of the ozone layer, and more observational evidence is needed. Further investigations suggest that biases embedded in total ozone records may significantly impact ozone trend estimations by resulting in large uncertainty or even negative rates of change after 2000.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMGC13A1047K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMGC13A1047K"><span>Climate Change and Political Instability in Syria</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kelley, C. P.; Mohtadi, S.; Cane, M. A.; Seager, R.; Kushnir, Y.</p> <p>2013-12-01</p> <p>From 2005 to 2010, Syria experienced the most severe and persistent drought in the instrumental record, devastating the agriculture and causing widespread crop failure. A mass migration of farming families to urban peripheries followed the resulting food shortages, unemployment, and disruption of rural social structure. The addition of nearly 1.5 million drought refugees to the recent influx of Iraqi refugees greatly exacerbated conditions in the urban slums. Anger at the government's failure to respond to the drought's impacts contributed to the political unrest that began in March 2011. The recent decrease in Syrian precipitation is a combination of natural variability and long-term drying trend, and the unusual severity of the observed drought is here shown to be highly unlikely without the trend. Precipitation changes in Syria are linked to rising mean sea-level pressure in the Eastern Mediterranean, which also shows a long-term trend. Compared to the natural variability alone, the trend has made the occurrence of such a severe drought eight times more likely. There has been also a long-term warming trend in Syria, adding to the drawdown of soil moisture. No natural cause is apparent for these trends, whereas the observed drying and warming are consistent with observed increases in greenhouse gases. Furthermore, model studies show an increasingly drier and hotter future mean climate for the Eastern Mediterranean. The severity and duration of the recent Syrian drought, implicated as a cause of the current conflict, is highly likely to be a consequence of human interference in the climate system.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28783913','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28783913"><span>Sea level anomaly in the North Atlantic and seas around Europe: Long-term variability and response to North Atlantic teleconnection patterns.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Iglesias, Isabel; Lorenzo, M Nieves; Lázaro, Clara; Fernandes, M Joana; Bastos, Luísa</p> <p>2017-12-31</p> <p>Sea level anomaly (SLA), provided globally by satellite altimetry, is considered a valuable proxy for detecting long-term changes of the global ocean, as well as short-term and annual variations. In this manuscript, monthly sea level anomaly grids for the period 1993-2013 are used to characterise the North Atlantic Ocean variability at inter-annual timescales and its response to the North Atlantic main patterns of atmospheric circulation variability (North Atlantic Oscillation, Eastern Atlantic, Eastern Atlantic/Western Russia, Scandinavian and Polar/Eurasia) and main driven factors as sea level pressure, sea surface temperature and wind fields. SLA variability and long-term trends are analysed for the North Atlantic Ocean and several sub-regions (North, Baltic and Mediterranean and Black seas, Bay of Biscay extended to the west coast of the Iberian Peninsula, and the northern North Atlantic Ocean), depicting the SLA fluctuations at basin and sub-basin scales, aiming at representing the regions of maximum sea level variability. A significant correlation between SLA and the different phases of the teleconnection patterns due to the generated winds, sea level pressure and sea surface temperature anomalies, with a strong variability on temporal and spatial scales, has been identified. Long-term analysis reveals the existence of non-stationary inter-annual SLA fluctuations in terms of the temporal scale. Spectral density analysis has shown the existence of long-period signals in the SLA inter-annual component, with periods of ~10, 5, 4 and 2years, depending on the analysed sub-region. Also, a non-uniform increase in sea level since 1993 is identified for all sub-regions, with trend values between 2.05mm/year, for the Bay of Biscay region, and 3.98mm/year for the Baltic Sea (no GIA correction considered). The obtained results demonstrated a strong link between the atmospheric patterns and SLA, as well as strong long-period fluctuations of this variable in spatial and temporal scales. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JESS..127...25B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JESS..127...25B"><span>Analysis of rainfall and temperature time series to detect long-term climatic trends and variability over semi-arid Botswana</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Byakatonda, Jimmy; Parida, B. P.; Kenabatho, Piet K.; Moalafhi, D. B.</p> <p>2018-03-01</p> <p>Arid and semi-arid environments have been identified with locations prone to impacts of climate variability and change. Investigating long-term trends is one way of tracing climate change impacts. This study investigates variability through annual and seasonal meteorological time series. Possible inhomogeneities and years of intervention are analysed using four absolute homogeneity tests. Trends in the climatic variables were determined using Mann-Kendall and Sen's Slope estimator statistics. Association of El Niño Southern Oscillation (ENSO) with local climate is also investigated through multivariate analysis. Results from the study show that rainfall time series are fully homogeneous with 78.6 and 50% of the stations for maximum and minimum temperature, respectively, showing homogeneity. Trends also indicate a general decrease of 5.8, 7.4 and 18.1% in annual, summer and winter rainfall, respectively. Warming trends are observed in annual and winter temperature at 0.3 and 1.5% for maximum temperature and 1.7 and 6.5% for minimum temperature, respectively. Rainfall reported a positive correlation with Southern Oscillation Index (SOI) and at the same time negative association with Sea Surface Temperatures (SSTs). Strong relationships between SSTs and maximum temperature are observed during the El Niño and La Niña years. These study findings could facilitate planning and management of agricultural and water resources in Botswana.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ApJ...851..116M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ApJ...851..116M"><span>Long-term Photometric Variability in Kepler Full-frame Images: Magnetic Cycles of Sun–like Stars</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Montet, Benjamin T.; Tovar, Guadalupe; Foreman-Mackey, Daniel</p> <p>2017-12-01</p> <p>Photometry from the Kepler mission is optimized to detect small, short-duration signals like planet transits at the expense of long-term trends. This long-term variability can be recovered in photometry from the full-frame images (FFIs), a set of calibration data collected approximately monthly during the Kepler mission. Here we present f3, an open-source package to perform photometry on the Kepler FFIs in order to detect changes in the brightness of stars in the Kepler field of view over long time baselines. We apply this package to a sample of 4000 Sun–like stars with measured rotation periods. We find that ≈10% of these targets have long-term variability in their observed flux. For the majority of targets, we find that the luminosity variations are either correlated or anticorrelated with the short-term variability due to starspots on the stellar surface. We find a transition between anticorrelated (starspot-dominated) variability and correlated (facula-dominated) variability between rotation periods of 15 and 25 days, suggesting the transition between the two modes is complete for stars at the age of the Sun. We also identify a sample of stars with apparently complete cycles, as well as a collection of short-period binaries with extreme photometric variation over the Kepler mission.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018IJBm...62..229F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018IJBm...62..229F"><span>Increasing Juniperus virginiana L. pollen in the Tulsa atmosphere: long-term trends, variability, and influence of meteorological conditions</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Flonard, Michaela; Lo, Esther; Levetin, Estelle</p> <p>2018-02-01</p> <p>In the Tulsa area, the Cupressaceae is largely represented by eastern red cedar ( Juniperus virginiana L.). The encroachment of this species into the grasslands of Oklahoma has been well documented, and it is believed this trend will continue. The pollen is known to be allergenic and is a major component of the Tulsa atmosphere in February and March. This study examined airborne Cupressaceae pollen data from 1987 to 2016 to determine long-term trends, pollen seasonal variability, and influence of meteorological variables on airborne pollen concentrations. Pollen was collected through means of a Burkard sampler and analyzed with microscopy. Daily pollen concentrations and yearly pollen metrics showed a high degree of variability. In addition, there were significant increases over time in the seasonal pollen index and in peak concentrations. These increases parallel the increasing population of J. virginiana in the region. Pollen data were split into pre- and post-peak categories for statistical analyses, which revealed significant differences in correlations of the two datasets when analyzed with meteorological conditions. While temperature and dew point, among others were significant in both datasets, other factors, like relative humidity, were significant only in one dataset. Analyses using wind direction showed that southerly and southwestern winds contributed to increased pollen concentrations. This study confirms that J. virginiana pollen has become an increasing risk for individuals sensitive to this pollen and emphasizes the need for long-term aerobiological monitoring in other areas.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active"><span>2</span></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_2 --> <div id="page_3" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="41"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=301237','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=301237"><span>Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>The Eco Trends Editorial Committee sorted through vast amounts of historical and ongoing data from 50 ecological sites in the continental United States including Alaska, several islands, and Antarctica to present in a logical format the variables commonly collected. This report presents a subset of...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ThApC.tmp...56M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ThApC.tmp...56M"><span>Assessment of short- and long-term memory in trends of major climatic variables over Iran: 1966-2015</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mianabadi, Ameneh; Shirazi, Pooya; Ghahraman, Bijan; Coenders-Gerrits, A. M. J.; Alizadeh, Amin; Davary, Kamran</p> <p>2018-02-01</p> <p>In arid and semi-arid regions, water scarcity is the crucial issue for crop production. Identifying the spatial and temporal trends in aridity, especially during the crop-growing season, is important for farmers to manage their agricultural practices. This will become especially relevant when considering climate change projections. To reliably determine the actual trends, the influence of short- and long-term memory should be removed from the trend analysis. The objective of this study is to investigate the effect of short- and long-term memory on estimates of trends in two aridity indicators—the inverted De Martonne (ϕ IDM ) and Budyko (ϕ B ) indices. The analysis is done using precipitation and temperature data over Iran for a 50-year period (1966-2015) at three temporal scales: annual, wheat-growing season (October-June), and maize-growing season (May-November). For this purpose, the original and the modified Mann-Kendall tests (i.e., modified by three methods of trend free pre-whitening (TFPT), effective sample size (ESS), and long-term persistence (LTP)) are used to investigate the temporal trends in aridity indices, precipitation, and temperature by taking into account the effect of short- and long-term memory. Precipitation and temperature data were provided by the Islamic Republic of Iran Meteorological Organization (IRIMO). The temporal trend analysis showed that aridity increased from 1966 to 2015 at the annual and wheat-growing season scales, which is due to a decreasing trend in precipitation and an increasing trend in mean temperature at these two timescales. The trend in aridity indices was decreasing in the maize-growing season, since precipitation has an increasing trend for most parts of Iran in that season. The increasing trend in aridity indices is significant in Western Iran, which can be related to the significantly more negative trend in precipitation in the West. This increasing trend in aridity could result in an increasing crop water requirement and a significant reduction in the crop production and water use efficiency. Furthermore, the modified Mann-Kendall tests indicated that unlike temperature series, precipitation, ϕ IDM , and ϕ B series are not affected by short- and long-term memory. Our results can help decision makers and water resource managers to adopt appropriate policy strategies for sustainable development in the field of irrigated agriculture and water resources management.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70176034','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70176034"><span>State-space modeling of population sizes and trends in Nihoa Finch and Millerbird</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Gorresen, P. Marcos; Brinck, Kevin W.; Camp, Richard J.; Farmer, Chris; Plentovich, Sheldon M.; Banko, Paul C.</p> <p>2016-01-01</p> <p>Both of the 2 passerines endemic to Nihoa Island, Hawai‘i, USA—the Nihoa Millerbird (Acrocephalus familiaris kingi) and Nihoa Finch (Telespiza ultima)—are listed as endangered by federal and state agencies. Their abundances have been estimated by irregularly implemented fixed-width strip-transect sampling from 1967 to 2012, from which area-based extrapolation of the raw counts produced highly variable abundance estimates for both species. To evaluate an alternative survey method and improve abundance estimates, we conducted variable-distance point-transect sampling between 2010 and 2014. We compared our results to those obtained from strip-transect samples. In addition, we applied state-space models to derive improved estimates of population size and trends from the legacy time series of strip-transect counts. Both species were fairly evenly distributed across Nihoa and occurred in all or nearly all available habitat. Population trends for Nihoa Millerbird were inconclusive because of high within-year variance. Trends for Nihoa Finch were positive, particularly since the early 1990s. Distance-based analysis of point-transect counts produced mean estimates of abundance similar to those from strip-transects but was generally more precise. However, both survey methods produced biologically unrealistic variability between years. State-space modeling of the long-term time series of abundances obtained from strip-transect counts effectively reduced uncertainty in both within- and between-year estimates of population size, and allowed short-term changes in abundance trajectories to be smoothed into a long-term trend.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70156109','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70156109"><span>Coral proxy record of decadal-scale reduction in base flow from Moloka'i, Hawaii</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Prouty, Nancy G.; Jupiter, Stacy D.; Field, Michael E.; McCulloch, Malcolm T.</p> <p>2009-01-01</p> <p>Groundwater is a major resource in Hawaii and is the principal source of water for municipal, agricultural, and industrial use. With a growing population, a long-term downward trend in rainfall, and the need for proper groundwater management, a better understanding of the hydroclimatological system is essential. Proxy records from corals can supplement long-term observational networks, offering an accessible source of hydrologic and climate information. To develop a qualitative proxy for historic groundwater discharge to coastal waters, a suite of rare earth elements and yttrium (REYs) were analyzed from coral cores collected along the south shore of Moloka'i, Hawaii. The coral REY to calcium (Ca) ratios were evaluated against hydrological parameters, yielding the strongest relationship to base flow. Dissolution of REYs from labradorite and olivine in the basaltic rock aquifers is likely the primary source of coastal ocean REYs. There was a statistically significant downward trend (−40%) in subannually resolved REY/Ca ratios over the last century. This is consistent with long-term records of stream discharge from Moloka'i, which imply a downward trend in base flow since 1913. A decrease in base flow is observed statewide, consistent with the long-term downward trend in annual rainfall over much of the state. With greater demands on freshwater resources, it is appropriate for withdrawal scenarios to consider long-term trends and short-term climate variability. It is possible that coral paleohydrological records can be used to conduct model-data comparisons in groundwater flow models used to simulate changes in groundwater level and coastal discharge.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29339266','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29339266"><span>Long-term trend analysis on total and extreme precipitation over Shasta Dam watershed.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Toride, Kinya; Cawthorne, Dylan L; Ishida, Kei; Kavvas, M Levent; Anderson, Michael L</p> <p>2018-06-01</p> <p>California's interconnected water system is one of the most advanced water management systems in the world, and understanding of long-term trends in atmospheric and hydrologic behavior has increasingly being seen as vital to its future well-being. Knowledge of such trends is hampered by the lack of long-period observation data and the uncertainty surrounding future projections of atmospheric models. This study examines historical precipitation trends over the Shasta Dam watershed (SDW), which lies upstream of one of the most important components of California's water system, Shasta Dam, using a dynamical downscaling methodology that can produce atmospheric data at fine time-space scales. The Weather Research and Forecasting (WRF) model is employed to reconstruct 159years of long-term hourly precipitation data at 3km spatial resolution over SDW using the 20th Century Reanalysis Version 2c dataset. Trend analysis on this data indicates a significant increase in total precipitation as well as a growing intensity of extreme events such as 1, 6, 12, 24, 48, and 72-hour storms over the period of 1851 to 2010. The turning point of the increasing trend and no significant trend periods is found to be 1940 for annual precipitation and the period of 1950 to 1960 for extreme precipitation using the sequential Mann-Kendall test. Based on these analysis, we find the trends at the regional scale do not necessarily apply to the watershed-scale. The sharp increase in the variability of annual precipitation since 1970s is also detected, which implies an increase in the occurrence of extreme wet and dry conditions. These results inform long-term planning decisions regarding the future of Shasta Dam and California's water system. Copyright © 2018 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...49.3735T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...49.3735T"><span>Trend and recovery of the total ozone column in South America and Antarctica</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Toro A., Richard; Araya, Consuelo; Labra O., Felipe; Morales, Luis; Morales, Raúl G. E.; Leiva G., Manuel A.</p> <p>2017-12-01</p> <p>South America is one of the most vulnerable areas to stratospheric ozone depletion; consequently, an increased amount of UV radiation reaches the Earth's surface in this region. In this study, we analyzed the long-term trend in the total ozone column (TOC) over the southern part of the South American continent from 1980 to 2009. The database used was obtained by combining several satellite measurements of the TOC on a 1° (latitude) × 1.25° (longitude) grid. Analysis of the long-term trend was performed by applying the Theil-Sen estimator and the Mann-Kendall significance test to the deseasonalized time series. The long-term trend was also analyzed over several highly populated urban zones in the study area. Finally, multiple linear regression (MLR) modeling was used to identify and quantify the drivers of interannual variability in the TOC over the study area with a pixel-by-pixel approach. The results showed a decrease in the TOC ranging from -0.3 to -4% dec-1 from 1980 to 2009. On a decadal timescale, there is significant variability in this trend, and a decrease of more than -10% dec-1 was found at high latitudes (1980-1989). However, the trends obtained over much of the study area were not statistically significant. Considering the period from 1980 to 1995, we found a decrease in the TOC of -2.0 ± 0.6% dec-1 at latitudes below 40° S and -6.9 ± 2.0% dec-1 at latitudes above 40° S, for a 99.9% confidence level over most of the study area. Analysis of the period from 1996 to 2009 showed a statistically significant increase of 2.3 ± 0.1% dec-1 at high latitudes (> 60° S), confirming the initial TOC recovery in the Antarctic. Despite evidence for initial recovery of the TOC in some parts of the study area between 1996 and 2009, the long-term increase from September to November is not yet statistically significant. In addition, large parts of the study area and most of the urban areas continue to show a decreasing trend in the TOC. The MLR results show that at high latitudes, the main driver of interannual variability in the TOC is the total effective amount of halogens, followed by the eddy heat flux.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005NPGeo..12..201K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005NPGeo..12..201K"><span>Trend assessment: applications for hydrology and climate research</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kallache, M.; Rust, H. W.; Kropp, J.</p> <p>2005-02-01</p> <p>The assessment of trends in climatology and hydrology still is a matter of debate. Capturing typical properties of time series, like trends, is highly relevant for the discussion of potential impacts of global warming or flood occurrences. It provides indicators for the separation of anthropogenic signals and natural forcing factors by distinguishing between deterministic trends and stochastic variability. In this contribution river run-off data from gauges in Southern Germany are analysed regarding their trend behaviour by combining a deterministic trend component and a stochastic model part in a semi-parametric approach. In this way the trade-off between trend and autocorrelation structure can be considered explicitly. A test for a significant trend is introduced via three steps: First, a stochastic fractional ARIMA model, which is able to reproduce short-term as well as long-term correlations, is fitted to the empirical data. In a second step, wavelet analysis is used to separate the variability of small and large time-scales assuming that the trend component is part of the latter. Finally, a comparison of the overall variability to that restricted to small scales results in a test for a trend. The extraction of the large-scale behaviour by wavelet analysis provides a clue concerning the shape of the trend.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PApGe.tmp...28R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PApGe.tmp...28R"><span>Search for Trends and Periodicities in Inter-hemispheric Sea Surface Temperature Difference</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rajesh, R.; Tiwari, R. K.</p> <p>2018-02-01</p> <p>Understanding the role of coupled solar and internal ocean dynamics on hemispheric climate variability is critical to climate modelling. We have analysed here 165 year long annual northern hemispheric (NH) and southern hemispheric (SH) sea surface temperature (SST) data employing spectral and statistical techniques to identify the imprints of solar and ocean-atmospheric processes, if any. We reconstructed the eigen modes of NH-SST and SH-SST to reveal non-linear oscillations superimposed on the monotonic trend. Our analysis reveals that the first eigen mode of NH-SST and SH-SST representing long-term trend of SST variability accounts for 15-23% variance. Interestingly, these components are matching with first eigen mode (99% variance) of the total solar irradiance (TSI) suggesting possible impact of solar activity on long-term SST variation. Furthermore, spectral analysis of SSA reconstructed signal revealed statistically significant periodicities of 63 ± 5, 22 ± 2, 10 ± 1, 7.6, 6.3, 5.2, 4.7, and 4.2 years in both NH-SST and SH-SST data. The major harmonics centred at 63 ± 5, 22 ± 2, and 10 ± 1 years are similar to solar periodicities and hence may represent solar forcing, while the components peaking at around 7.6, 6.3, 5.2, 4.7, and 4.2 years apparently falls in the frequency bands of El-Nino-Southern Oscillations linked to the oceanic internal processes. Our analyses also suggest evidence for the amplitude modulation of 9-11 and 21-22 year solar cycles, respectively, by 104 and 163 years in northern and southern hemispheric SST data. The absence of the above periodic oscillations in CO2 fails to suggest its role on observed inter-hemispheric SST difference. The cross-plot analysis also revealed strong influence of solar activity on linear trend of NH- and SH-SST in addition to small contribution from CO2. Our study concludes that (1) the long-term trends in northern and southern hemispheric SST variability show considerable synchronicity with cyclic warming and cooling phases and (2) the difference in cyclic forcing and non-linear modulations stemming from solar variability as a possible source of hemispheric SST differences.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920006214','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920006214"><span>Global trends</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Megie, G.; Chanin, M.-L.; Ehhalt, D.; Fraser, P.; Frederick, J. F.; Gille, J. C.; Mccormick, M. P.; Schoebert, M.; Bishop, L.; Bojkov, R. D.</p> <p>1990-01-01</p> <p>Measuring trends in ozone, and most other geophysical variables, requires that a small systematic change with time be determined from signals that have large periodic and aperiodic variations. Their time scales range from the day-to-day changes due to atmospheric motions through seasonal and annual variations to 11 year cycles resulting from changes in the sun UV output. Because of the magnitude of all of these variations is not well known and highly variable, it is necessary to measure over more than one period of the variations to remove their effects. This means that at least 2 or more times the 11 year sunspot cycle. Thus, the first requirement is for a long term data record. The second related requirement is that the record be consistent. A third requirement is for reasonable global sampling, to ensure that the effects are representative of the entire Earth. The various observational methods relevant to trend detection are reviewed to characterize their quality and time and space coverage. Available data are then examined for long term trends or recent changes in ozone total content and vertical distribution, as well as related parameters such as stratospheric temperature, source gases and aerosols.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29043046','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29043046"><span>Among-tree variability and feedback effects result in different growth responses to climate change at the upper treeline in the Swiss Alps.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jochner, Matthias; Bugmann, Harald; Nötzli, Magdalena; Bigler, Christof</p> <p>2017-10-01</p> <p>Upper treeline ecotones are important life form boundaries and particularly sensitive to a warming climate. Changes in growth conditions at these ecotones have wide-ranging implications for the provision of ecosystem services in densely populated mountain regions like the European Alps. We quantify climate effects on short- and long-term tree growth responses, focusing on among-tree variability and potential feedback effects. Although among-tree variability is thought to be substantial, it has not been considered systematically yet in studies on growth-climate relationships. We compiled tree-ring data including almost 600 trees of major treeline species ( Larix decidua , Picea abies , Pinus cembra , and Pinus mugo ) from three climate regions of the Swiss Alps. We further acquired tree size distribution data using unmanned aerial vehicles. To account for among-tree variability, we employed information-theoretic model selections based on linear mixed-effects models (LMMs) with flexible choice of monthly temperature effects on growth. We isolated long-term trends in ring-width indices (RWI) in interaction with elevation. The LMMs revealed substantial amounts of previously unquantified among-tree variability, indicating different strategies of single trees regarding when and to what extent to invest assimilates into growth. Furthermore, the LMMs indicated strongly positive temperature effects on growth during short summer periods across all species, and significant contributions of fall ( L. decidua ) and current year's spring ( L. decidua , P. abies ). In the longer term, all species showed consistently positive RWI trends at highest elevations, but different patterns with decreasing elevation. L. decidua exhibited even negative RWI trends compared to the highest treeline sites, whereas P. abies , P. cembra , and P. mugo showed steeper or flatter trends with decreasing elevation. This does not only reflect effects of ameliorated climate conditions on tree growth over time, but also reveals first signs of long-suspected negative and positive feedback of climate change on stand dynamics at treeline.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H13J1228C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H13J1228C"><span>Long Term Trend Analysis and Assessment of Water Quality in the Penchala River, Malaysia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chow, M. F.; Haris, H. B.; Mohd Sidek, L. B.</p> <p>2014-12-01</p> <p>Rapid urban expansion produces negative impacts on the natural environment, especially river water quality. Studies assessing long term changes of water quality have been recognized as a key tool for understanding ongoing processes in watersheds and for providing an essential background for evaluation of rapid changes within industrialized and populated urban areas. Unfortunately, only limited studies are available for developing countries such as Malaysia. Thus, a long term study was conducted to evaluate water quality trends at Pencala river basin that has undergone extensive land use changes related to industrial, agricultural and urban activities. Fifteen physical and chemical variables were analysed in river water samples collected every month over a period of 13 years, between 1997 and 2009. The trend study was performed using the Mann-Kendall Seasonal test and the Sen's Slope estimator. Results revealed that most water quality parameters showed a downward trend for yearly average concentration. The water quality index (WQI) for Pencala River was improved from Class V to Class IV, according to National Water Quality Standards for Malaysia. BOD, COD, NH3-N and SS show trends toward decreasing concentrations over time. The improvements seen in water quality appear to be the result of improved wastewater treatment and other water quality improvement efforts achieved through government initiative. Continued long-term and high frequency monitoring is necessary to establish plans and policies for effective water resources management.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010ECSS...86..225K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010ECSS...86..225K"><span>Dynamic factor analysis of long-term growth trends of the intertidal seagrass Thalassia hemprichii in southern Taiwan</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kuo, Yi-Ming; Lin, Hsing-Juh</p> <p>2010-01-01</p> <p>We examined environmental factors which are most responsible for the 8-year temporal dynamics of the intertidal seagrass Thalassia hemprichii in southern Taiwan. A dynamic factor analysis (DFA), a dimension-reduction technique, was applied to identify common trends in a multivariate time series and the relationships between this series and interacting environmental variables. The results of dynamic factor models (DFMs) showed that the leaf growth rate of the seagrass was mainly influenced by salinity (Sal), tidal range (TR), turbidity ( K), and a common trend representing an unexplained variability in the observed time series. Sal was the primary variable that explained the temporal dynamics of the leaf growth rate compared to TR and K. K and TR had larger influences on the leaf growth rate in low- than in high-elevation beds. In addition to K, TR, and Sal, UV-B radiation (UV-B), sediment depth (SD), and a common trend accounted for long-term temporal variations of the above-ground biomass. Thus, K, TR, Sal, UV-B, and SD are the predominant environmental variables that described temporal growth variations of the intertidal seagrass T. hemprichii in southern Taiwan. In addition to environmental variables, human activities may be contributing to negative impacts on the seagrass beds; this human interference may have been responsible for the unexplained common trend in the DFMs. Due to successfully applying the DFA to analyze complicated ecological and environmental data in this study, important environmental variables and impacts of human activities along the coast should be taken into account when managing a coastal environment for the conservation of intertidal seagrass beds.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24324869','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24324869"><span>Forest insects and climate change: long-term trends in herbivore damage.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Klapwijk, Maartje J; Csóka, György; Hirka, Anikó; Björkman, Christer</p> <p>2013-10-01</p> <p>Long-term data sets, covering several decades, could help to reveal the effects of observed climate change on herbivore damage to plants. However, sufficiently long time series in ecology are scarce. The research presented here analyzes a long-term data set collected by the Hungarian Forest Research Institute over the period 1961-2009. The number of hectares with visible defoliation was estimated and documented for several forest insect pest species. This resulted in a unique time series that provides us with the opportunity to compare insect damage trends with trends in weather patterns. Data were analyzed for six lepidopteran species: Thaumetopoea processionea, Tortrix viridana, Rhyacionia buoliana, Malacosoma neustria, Euproctis chrysorrhoea, and Lymantria dispar. All these species exhibit outbreak dynamics in Hungary. Five of these species prefer deciduous tree species as their host plants, whereas R. buoliana is a specialist on Pinus spp. The data were analyzed using general linear models and generalized least squares regression in relation to mean monthly temperature and precipitation. Temperature increased considerably, especially over the last 25 years (+1.6°C), whereas precipitation exhibited no trend over the period. No change in weather variability over time was observed. There was increased damage caused by two species on deciduous trees. The area of damage attributed to R. buoliana decreased over the study period. There was no evidence of increased variability in damage. We conclude that species exhibiting a trend toward outbreak-level damage over a greater geographical area may be positively affected by changes in weather conditions coinciding with important life stages. Strong associations between the geographical extent of severe damage and monthly temperature and precipitation are difficult to confirm, studying the life-history traits of species could help to increase understanding of responses to climate change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2005/5224/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2005/5224/"><span>Water-quality trend analysis and sampling design for streams in the Red River of the North Basin, Minnesota, North Dakota, and South Dakota, 1970-2001</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Vecchia, Aldo V.</p> <p>2005-01-01</p> <p>The Bureau of Reclamation is considering several alternatives to meet the future municipal, rural, and industrial water-supply needs in the Red River of the North (Red River) Basin, and an environmental impact statement is being prepared to evaluate the potential effects of the various alternatives on the water quality and aquatic health in the basin in relation to the historical variability of streamflow and constituent concentration. Therefore, a water-quality trend analysis was needed to determine the amount of natural water-quality variability that can be expected to occur in the basin, to determine if significant water-quality changes have occurred as a result of human activities, to explore potential causal mechanisms for water-quality changes, and to establish a baseline from which to monitor future water-quality trends. This report presents the results of a study conducted by the U.S. Geological Survey, in cooperation with the Bureau of Reclamation, to analyze historical water-quality trends in two dissolved major ions, dissolved solids, three nutrients, and two dissolved trace metals for nine streamflow-gaging stations in the basin. Annual variability in streamflow in the Red River Basin was high during the trend-analysis period (1970-2001). The annual variability affects constituent concentrations in individual tributaries to the Red River and, in turn, affects constituent concentrations in the main stem of the Red River because of the relative streamflow contribution from the tributaries to the main stem. Therefore, an annual concentration anomaly, which is an estimate of the interannual variability in concentration that can be attributed to long-term variability in streamflow, was used to analyze annual streamflow-related variability in constituent concentrations. The concentration trend is an estimate of the long-term systematic changes in concentration that are unrelated to seasonal or long-term variability in streamflow. Concentrations that have both the seasonal and annual variability removed are called standardized concentrations. Numerous changes that could not be attributed to natural streamflow-related variability occurred in the standardized concentrations during the trend-analysis period. During various times from the late 1970's to the mid-1990's, significant increases occurred in standardized dissolved sulfate, dissolved chloride, and dissolved- solids concentrations for eight of the nine stations for which water-quality trends were analyzed. Significant increases also occurred from the early 1980's to the mid-1990's for standardized dissolved nitrite plus nitrate concentrations for the main-stem stations. The increasing concentrations for the main-stem stations indicate the upward trends may have been caused by human activities along the main stem of the Red River. Significant trends for standardized total ammonia plus organic nitrogen concentrations occurred for most stations. The fitted trends for standardized total phosphorus concentrations for one tributary station increased from the late 1970's to the early 1980's and decreased from the early 1980's to the mid-1990's. Small but insignificant increases occurred for two main-stem stations. No trends were detected for standardized dissolved iron or dissolved manganese concentrations. However, the combination of extreme high-frequency variability, few data, and the number of censored values may have disguised the streamflow-related variability for iron. The time-series model used to detect historical concentration trends also was used to evaluate sampling designs to monitor future water-quality trends. Various sampling designs were evaluated with regard to their sensitivity to detect both annual and seasonal trends during three 4-month seasons. A reasonable overall design for detecting trends for all stations and constituents consisted of eight samples per year, with monthly sampling from April to August and bimonthly sampling from October to February.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMSA33B..07L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMSA33B..07L"><span>Stratospheric effects on trends of mesospheric ice clouds (Invited)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luebken, F.; Baumgarten, G.; Berger, U.</p> <p>2009-12-01</p> <p>Ice layers in the summer mesosphere at middle and polar latitudes appear as `noctilucent clouds' (NLC) and `polar mesosphere clouds'(PMC) when observed by optical methods from the ground or from satellites, respectively. A newly developed model of the atmosphere called LIMA (Leibniz Institute Middle Atmosphere Model) nicely reproduces the mean conditions of the summer mesopause region and is used to study the ice layer morphology (LIMA/ice). LIMA nudges to ECMWF data in the troposphere and lower stratosphere which influences the background conditions in the mesosphere and ice cloud morphology. Since ice layer formation is very sensitive to the thermal structure of the mesopause region the morphology of NLC and PMC is frequently discussed in terms of long term variations. Model runs of LIMA/ice are now available for 1961 until 2008. A strong correlation between temperatures and PMC altitudes is observed. Applied to historical measurements this gives negligible temperature trends at PMC altitudes (approximately 0.01-0.02 K/y). Trace gas concentrations are kept constant in LIMA except for water vapor which is modified by variable solar radiation. Still, long term trends in temperatures and ice layer parameters are observed, consistent with observations. We present results regarding inter-annual variability of upper mesosphere temperatures, water vapor, and ice clouds, and also long term variations. We compare our model results with satellite borne and lidar observations including some record high NLC parameters measured in the summer season of 2009. The latitudinal dependence of trends and ice layer parameters is discussed, including a NH/SH comparison. We will present an explanation of the trends in the background atmosphere and ice layer parameters.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PrOce..87..114L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PrOce..87..114L"><span>Changing climate in the Gulf of California</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lluch-Cota, Salvador E.; Parés-Sierra, Alejandro; Magaña-Rueda, Víctor O.; Arreguín-Sánchez, Francisco; Bazzino, Gastón; Herrera-Cervantes, Hugo; Lluch-Belda, Daniel</p> <p>2010-10-01</p> <p>We conducted a four year interdisciplinary collaborative project focused in the Gulf of California, the most important fishing region for Mexico. We reviewed published reports, collected and analyzed physical, chemical and ecological data sets, and developed models for the physical (atmosphere and ocean) and ecological components of this large marine ecosystem, to examine prevalent scientific questions regarding climate variability and change in the region, covering three time scales (ENSO, decadal-to-interdecadal, and long-term trend). We were able to describe how the Gulf of California influences the northward propagation of coastal trapped Kelvin waves associated with El Niño (ENSO) events, and how this signal, together with changes in the atmospheric forcing, results in a ENSO signature inside the Gulf. For the decadal-to-multidecadal scales, we found coherent trends among series, and with the Pacific Decadal Oscillation (PDO). The long-term temperature signal for the Gulf of California shows a warming that occurred in the mid 20th century, approximately a decade before that in the California Current. This signal is coherent with fluctuations in the industrial fisheries catch records (sardine and shrimps). For the recent decades we found no significant sustained long-term trend in any of the time series of physical and ecological variables that we considered. Instead, variability seems to be fully dominated by the interaction of PDO and ENSO. We stress the urgent need for more modeling efforts and the establishment of interdisciplinary (physical and biological) observation platforms for the marine environment in the Gulf of California.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70039900','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70039900"><span>Temporal changes in aquatic-invertebrate and fish assemblages in streams of the north-central and northeastern U.S.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kennen, Jonathan G.; Sullivan, Daniel J.; May, Jason T.; Bell, Amanda H.; Beaulieu, Karen M.; Rice, Donald E.</p> <p>2012-01-01</p> <p>Many management agencies seek to evaluate temporal changes in aquatic assemblages at monitoring sites, but few have sites with ecological time series that are long enough for this purpose. Trends in aquatic-invertebrate and fish assemblage composition were assessed at 27 long-term monitoring sites in the north-central and northeastern United States. Temporal changes were identified using serial trend analysis. Sites with significant serial trends were further evaluated by relating explanatory environmental variables (e.g., streamflow, habitat, and water chemistry) to changes in assemblage composition. Significant trends were found at 19 of 27 study sites; however, differences in the sensitivity of the aquatic fauna to environmental stressors were identified. For example, significant trends in fish assemblages were found at more sites (15 of 27) than for aquatic-invertebrate assemblages (10 of 27 sites). In addition, trends in the invertebrate assemblage were most often explained by changes in streamflow processes (e.g., duration and magnitude of low- and high-flows, streamflow variability, and annual rates of change), whereas trends in the fish assemblage were more related to changes in water chemistry. Results illustrate the value of long-term monitoring for the purpose of assessing temporal trends in aquatic assemblages. The ability to detect trends in assemblage composition and to attribute these changes to environmental factors is necessary to understand mechanistic pathways and to further our understanding of how incremental anthropogenic alterations modify aquatic assemblages over time. Finally, this study's approach to trends analysis can be used to better inform the design of monitoring programs as well as support the ongoing management needs of stakeholders, water-resource agencies, and policy makers.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70148393','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70148393"><span>Changes in erosion and flooding risk due to long-term and cyclic oceanographic trends</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wahl, Thomas; Plant, Nathaniel G.</p> <p>2015-01-01</p> <p>We assess temporal variations in waves and sea level, which are driving factors for beach 23 erosion and coastal flooding in the northern Gulf of Mexico. We find that long-term trends in 24 the relevant variables have caused an increase of ~30% in the erosion/flooding risk since the 25 1980s. Changes in the wave climate-which have often been ignored in earlier assessments-26 were at least as important as sea-level rise (SLR). In the next decades, SLR will likely become 27 the dominating driver and may in combination with ongoing changes in the wave climate (and 28 depending on the emission scenario) escalate the erosion/flooding risk by up to 300% over the 29 next 30 years. We also find significant changes in the seasonal cycles of sea level and 30 significant wave height, which have in combination caused a considerable increase of the 31 erosion/flooding risk in summer and decrease in winter (superimposed onto the long-term 32 trends)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4122154','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4122154"><span>Skin Cancer, Irradiation, and Sunspots: The Solar Cycle Effect</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zurbenko, Igor</p> <p>2014-01-01</p> <p>Skin cancer is diagnosed in more than 2 million individuals annually in the United States. It is strongly associated with ultraviolet exposure, with melanoma risk doubling after five or more sunburns. Solar activity, characterized by features such as irradiance and sunspots, undergoes an 11-year solar cycle. This fingerprint frequency accounts for relatively small variation on Earth when compared to other uncorrelated time scales such as daily and seasonal cycles. Kolmogorov-Zurbenko filters, applied to the solar cycle and skin cancer data, separate the components of different time scales to detect weaker long term signals and investigate the relationships between long term trends. Analyses of crosscorrelations reveal epidemiologically consistent latencies between variables which can then be used for regression analysis to calculate a coefficient of influence. This method reveals that strong numerical associations, with correlations >0.5, exist between these small but distinct long term trends in the solar cycle and skin cancer. This improves modeling skin cancer trends on long time scales despite the stronger variation in other time scales and the destructive presence of noise. PMID:25126567</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://edg.epa.gov/metadata/catalog/search/resource/details.page?uuid=%7B158C2A61-9300-4D93-AF79-54D7D22DEB34%7D','PESTICIDES'); return false;" href="https://edg.epa.gov/metadata/catalog/search/resource/details.page?uuid=%7B158C2A61-9300-4D93-AF79-54D7D22DEB34%7D"><span>Data for Figures and Tables in Journal Article Assessment of the Effects of Horizontal Grid Resolution on Long-Term Air Quality Trends using Coupled WRF-CMAQ Simulations, doi:10.1016/j.atmosenv.2016.02.036</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>The dataset represents the data depicted in the Figures and Tables of a Journal Manuscript with the following abstract: The objective of this study is to determine the adequacy of using a relatively coarse horizontal resolution (i.e. 36 km) to simulate long-term trends of pollutant concentrations and radiation variables with the coupled WRF-CMAQ model. WRF-CMAQ simulations over the continental United State are performed over the 2001 to 2010 time period at two different horizontal resolutions of 12 and 36 km. Both simulations used the same emission inventory and model configurations. Model results are compared both in space and time to assess the potential weaknesses and strengths of using coarse resolution in long-term air quality applications. The results show that the 36 km and 12 km simulations are comparable in terms of trends analysis for both pollutant concentrations and radiation variables. The advantage of using the coarser 36 km resolution is a significant reduction of computational cost, time and storage requirement which are key considerations when performing multiple years of simulations for trend analysis. However, if such simulations are to be used for local air quality analysis, finer horizontal resolution may be beneficial since it can provide information on local gradients. In particular, divergences between the two simulations are noticeable in urban, complex terrain and coastal regions.This dataset is associated with the following publication</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C23D..05L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C23D..05L"><span>How important is interannual variability in the climatic interpretation of moraine sequences?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leonard, E. M.; Laabs, B. J. C.; Plummer, M. A.</p> <p>2017-12-01</p> <p>Mountain glaciers respond to both long-term climate and interannual forcing. Anderson et al. (2014) pointed out that kilometer-scale fluctuations in glacier length may result from interannual variability in temperature and precipitation given a "steady" climate with no long-term trends in mean or variability of temperature and precipitation. They cautioned that use of outermost moraines from the Last Glacial Maximum (LGM) as indicators of LGM climate will, because of the role of interannual forcing, result in overestimation of the magnitude of long-term temperature depression and/or precipitation enhancement. Here we assess the implications of these ideas, by examining the effect of interannual variability on glacier length and inferred magnitude of LGM climate change from present under both an assumed steady LGM climate and an LGM climate with low-magnitude, long-period variation in summer temperature and annual precipitation. We employ both the original 1-stage linear glacier model (Roe and O'Neal, 2009) used by Anderson et al. (2014) and a newer 3-stage linear model (Roe and Baker, 2014). We apply the models to two reconstructed LGM glaciers in the Colorado Sangre de Cristo Mountains. Three-stage-model results indicate that, absent long-term variations through a 7500-year-long LGM, interannual variability would result in overestimation of mean LGM temperature depression from the outermost moraine of 0.2-0.6°C. If small long-term cyclic variations of temperature (±0.5°C) and precipitation (±5%) are introduced, the overestimation of LGM temperature depression reduces to less than 0.4°C, and if slightly greater long-term variation (±1.0°C and ±10% precipitation) is introduced, the magnitude of overestimation is 0.3°C or less. Interannual variability may produce a moraine sequence that differs from the sequence that would be expected were glacier length forced only by long-term climate. With small amplitude (±0.5°C and ±5% precipitation) long-term variation, the moraine sequence expected if forced by a combination of interannual variability and long-term climate differs from that expected based on long-term climate forcing alone in 38% of model runs. With the larger amplitude long-term forcing (±1.0°C and ±10% precipitation) this difference occurs in 20% of model runs.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B33H..05C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B33H..05C"><span>Trends and Controls of inter-annual Variability in the Carbon Budget of Terrestrial Ecosystems</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cescatti, A.; Marcolla, B.</p> <p>2014-12-01</p> <p>The climate sensitivity of the terrestrial carbon budget will substantially affect the sign and strength of the land-climate feedbacks and the future climate trajectories. Current trends in the inter-annual variability of terrestrial carbon fluxes (IAV) may contribute to clarify the relative role of physical and biological controls of ecosystem responses to climate change. For this purpose we investigated how recent climate variability has impacted the carbon fluxes at long-term FLUXNET sites. Using a novel method, the IAV has been factored out in climate induced variability (physical control), variability due to changes in ecosystem functioning (biological control) and the interaction of the two terms. The relative control of the main climatic drivers (temperature, water availability) on the physical and biological sources of IAV has been investigated using both site level fluxes and global gridded products generated from the up-scaling of flux data. Results of this analysis highlight the fundamental role of precipitation trends on the pattern of IAV in the last 30 years. Our findings on the spatial/temporal trends of IAV have been finally confirmed using the signal derived from the global network of atmospheric CO2 concentrations measurements.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.5528B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.5528B"><span>Ozone time scale decomposition and trend assessment from surface observations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Boleti, Eirini; Hueglin, Christoph; Takahama, Satoshi</p> <p>2017-04-01</p> <p>Emissions of ozone precursors have been regulated in Europe since around 1990 with control measures primarily targeting to industries and traffic. In order to understand how these measures have affected air quality, it is now important to investigate concentrations of tropospheric ozone in different types of environments, based on their NOx burden, and in different geographic regions. In this study, we analyze high quality data sets for Switzerland (NABEL network) and whole Europe (AirBase) for the last 25 years to calculate long-term trends of ozone concentrations. A sophisticated time scale decomposition method, called the Ensemble Empirical Mode Decomposition (EEMD) (Huang,1998;Wu,2009), is used for decomposition of the different time scales of the variation of ozone, namely the long-term trend, seasonal and short-term variability. This allows subtraction of the seasonal pattern of ozone from the observations and estimation of long-term changes of ozone concentrations with lower uncertainty ranges compared to typical methodologies used. We observe that, despite the implementation of regulations, for most of the measurement sites ozone daily mean values have been increasing until around mid-2000s. Afterwards, we observe a decline or a leveling off in the concentrations; certainly a late effect of limitations in ozone precursor emissions. On the other hand, the peak ozone concentrations have been decreasing for almost all regions. The evolution in the trend exhibits some differences between the different types of measurement. In addition, ozone is known to be strongly affected by meteorology. In the applied approach, some of the meteorological effects are already captured by the seasonal signal and already removed in the de-seasonalized ozone time series. For adjustment of the influence of meteorology on the higher frequency ozone variation, a statistical approach based on Generalized Additive Models (GAM) (Hastie,1990;Wood,2006), which corrects for meteorological effects, has been developed in order to a) investigate if trends are masked by meteorological variability and b) to understand which part of the observed trends is meteorology driven. By correlating short-term variation of ozone, as obtained from the EEMD, with the corresponding short-term variation of relevant meteorological parameters, we subtract the variation of ozone concentrations that is related to the meteorological effects explained by the GAM. We find that higher frequency meteorological correction reduces further the uncertainty in trend estimation by a small factor. In addition, the seasonal variability of ozone as obtained from the EEMD has been studied in more detail for possible changes in its behavior. A shortening of the seasonal cycle was observed, i.e. reduction of maximum and in-crease of minimum concentration per year, while the occurrence of maximum is shifted to earlier times during a year. In summary, we present a sophisticated and consistent approach for detecting and categorizing trends and meteorological influences on ozone concentrations in long-term measurements across Europe.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2005/5105/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2005/5105/"><span>Streamflow characteristics and trends in New Jersey, water years 1897-2003</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Watson, Kara M.; Reiser, Robert G.; Nieswand, Steven P.; Schopp, Robert D.</p> <p>2005-01-01</p> <p>Streamflow statistics were computed for 111 continuous-record streamflow-gaging stations with 20 or more years of continuous record and for 500 low-flow partial-record stations, including 66 gaging stations with less than 20 years of continuous record. Daily mean streamflow data from water year 1897 through water year 2001 were used for the computations at the gaging stations. (The water year is the 12-month period, October 1 through September 30, designated by the calendar year in which it ends). The characteristics presented for the long-term continuous-record stations are daily streamflow, harmonic mean flow, flow frequency, daily flow durations, trend analysis, and streamflow variability. Low-flow statistics for gaging stations with less than 20 years of record and for partial-record stations were estimated by correlating base-flow measurements with daily mean flows at long-term (more than 20 years) continuous-record stations. Instantaneous streamflow measurements through water year 2003 were used to estimate low-flow statistics at the partial-record stations. The characteristics presented for partial-record stations are mean annual flow; harmonic mean flow; and annual and winter low-flow frequency. The annual 1-, 7-, and 30-day low- and high-flow data sets were tested for trends. The results of trend tests for high flows indicate relations between upward trends for high flows and stream regulation, and high flows and development in the basin. The relation between development and low-flow trends does not appear to be as strong as for development and high-flow trends. Monthly, seasonal, and annual precipitation data for selected long-term meteorological stations also were tested for trends to analyze the effects of climate. A significant upward trend in precipitation in northern New Jersey, Climate Division 1 was identified. For Climate Division 2, no general increase in average precipitation was observed. Trend test results indicate that high flows at undeveloped, unregulated sites have not been affected by the increase in average precipitation. The ratio of instantaneous peak flow to 3-day mean flow, ratios of flow duration, ratios of high-flow/low-flow frequency, and coefficient of variation were used to define streamflow variability. Streamflow variability was significantly greater among the group of gaging stations located outside the Coastal Plain than among the group of gaging stations located in the Coastal Plain.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B42A..02F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B42A..02F"><span>Using Time Series of Landsat Data to Improve Understanding of Short- and Long-Term Changes to Vegetation Phenology in Response to Climate Change</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Friedl, M. A.; Melaas, E. K.; Sulla-menashe, D. J.; Gray, J. M.</p> <p>2014-12-01</p> <p>Phenology, the seasonal progression of organisms through stages of dormancy, active growth, and senescence is a key regulator of ecosystem processes and is widely used as an indicator of vegetation responses to climate change. This is especially true in temperate forests, where seasonal dynamics in canopy development and senescence are tightly coupled to the climate system. Despite this, understanding of climate-phenology interactions is incomplete. A key impediment to improving this understanding is that available datasets are geographically sparse, and in most cases include relatively short time series. Remote sensing has been widely promoted as a useful tool for studies of large-scale phenology, but long-term studies from remote sensing have been limited to AVHRR data, which suffers from limitations related to its coarse spatial resolution and uncertainties in atmospheric corrections and radiometric adjustments that are used to create AVHRR time series. In this study, we used 30 years of Landsat data to quantify the nature and magnitude of long-term trends and short-term variability in the timing of spring leaf emergence and fall senescence. Our analysis focuses on temperate forest locations in the Northeastern United States that are co-located with surface meteorological observations, where we have estimated the timing of leaf emergence and leaf senescence at annual time steps using atmospherically corrected surface reflectances from Landsat TM and ETM+ imagery. Comparison of results from Landsat against ground observations demonstrates that phenological events can be reliably estimated from Landsat time series. More importantly, results from this analysis suggest two main conclusions related to the nature of climate change impacts on temperate forest phenology. First, there is clear evidence of trends towards longer growing seasons in the Landsat record. Second, interannual variability is large, with average year-to-year variability exceeding the magnitude of total changes to the growing season that have occurred over the last three decades. Based on these results we suggest that year-to-year variability in phenology, rather than long-term trends, provides the best basis for predicting future changes in temperate forest phenology in response to climate change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GeoRL..41.5571B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GeoRL..41.5571B"><span>Long-term sea level trends: Natural or anthropogenic?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Becker, M.; Karpytchev, M.; Lennartz-Sassinek, S.</p> <p>2014-08-01</p> <p>Detection and attribution of human influence on sea level rise are important topics that have not yet been explored in depth. We question whether the sea level changes (SLC) over the past century were natural in origin. SLC exhibit power law long-term correlations. By estimating Hurst exponent through Detrended Fluctuation Analysis and by applying statistics of Lennartz and Bunde, we search the lower bounds of statistically significant external sea level trends in longest tidal records worldwide. We provide statistical evidences that the observed SLC, at global and regional scales, is beyond its natural internal variability. The minimum anthropogenic sea level trend (MASLT) contributes to the observed sea level rise more than 50% in New York, Baltimore, San Diego, Marseille, and Mumbai. A MASLT is about 1 mm/yr in global sea level reconstructions that is more than half of the total observed sea level trend during the XXth century.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1914650R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1914650R"><span>Temporal variability and coloured noise of SLR translations with respect to the ITRF2014 origin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Riddell, Anna; King, Matt; Watson, Christopher; Rietbroek, Roelof; Sun, Yu; Riva, Riccardo</p> <p>2017-04-01</p> <p>Inferring large-scale environmental change, such as of sea-level change, glacial isostatic adjustment or ice sheet volume change (i.e. from altimetry), requires a geodetic reference frame stable to 0.1 mm/yr. Since 1988, each iterative improvement in the precision of the International Terrestrial Reference Frame (ITRF) has enabled significant advancement of scientific and technical research in the Earth sciences. We demonstrate the occurrence of coloured noise in the translation components between the SLR network and the long-term ITRF2014 origin from 1993.0 to 2015.0 with power law spectral indices close to -1, where white-noise-only linear trend uncertainties are underestimated by a factor of five in contrast to power-law linear trend uncertainties. The observed geocentre motion is expected to be influenced by the SLR observing network, known as the "network effect". Temporal translations in the SLR network may not necessarily average out over long time periods and therefore have the potential to shift the computed reference frame origin from the true long term centre of mass. Comparison with geophysical loading models demonstrates that the variability cannot be fully accounted for by surface mass transport such as changes in atmospheric, hydrologic or glacial loading. Our results demonstrate that the proportion of variance explained by geophysical surface loading is less than 50% in each translational component. Evidence of temporal variability in both the SLR amplitude and trend of the annual signal suggest that a different coloured noise model be considered in place of, or as an extension of, the traditional linear and white-noise-only model to represent the long-term average centre of mass.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29020363','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29020363"><span>Pneumonia Mortality in Children Aged <5 Years in 56 Countries: A Retrospective Analysis of Trends from 1960 to 2012.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wu, Jie; Yang, Shigui; Cao, Qing; Ding, Cheng; Cui, Yuanxia; Zhou, Yuqing; Li, Yiping; Deng, Min; Wang, Chencheng; Xu, Kaijin; Ruan, Bing; Li, Lanjuan</p> <p>2017-10-30</p> <p>Pneumonia is now the second leading cause of death for children aged <5 years worldwide. However, analyses of the long-term evolution of under-5 mortality from pneumonia are still scarce in the literature. We aimed to explore long-term trends of under-5 mortality from pneumonia in 56 countries from 1960 to 2012. Data on under-5 mortality from pneumonia were extracted from the World Health Organization mortality database. Long-term trends were assessed for 56 countries and for 4 national income transition groups. We also used joinpoint regression analysis to detect distinct period segments of long-term trends and estimate the annual percent of changes of each period segment. The average mortality rate from pneumonia for children aged 0-4 years in 56 countries declined from 163.0 per 100000 children (95% confidence interval [CI], 119.4 to 212.8) in 1960 to 9.9 per 100000 children (95% CI, 6.4 to 13.4) in 2012, with an average annual percent of change of -5.6% (95% CI, -7.2% to -3.9%). The temporal trends of childhood mortality were different between national income transition groups. Our findings suggest a striking overall downward trend in under-5 mortality from pneumonia between 1960 and 2012. However, the rate and absolute terms of decline differ by national income transition group. These variable patterns between national income transition groups may inform further intervention setting and priority setting. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.6964L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.6964L"><span>Long-term variability of aerosol optical properties and radiative effects in Northern Finland</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lihavainen, Heikki; Hyvärinen, Antti; Asmi, Eija; Hatakka, Juha; Viisanen, Yrjö</p> <p>2017-04-01</p> <p>We introduce long term dataset of aerosol scattering and absorption properties and combined aerosol optical properties measured in Pallas Atmosphere-Ecosystem Supersite in Norhern Finland. The station is located 170 km north of the Arctic Circle. The station is affected by both pristine Arctic air masses as well as long transported air pollution from northern Europe. We studied the optical properties of aerosols and their radiative effects in continental and marine air masses, including seasonal cycles and long-term trends. The average (median) scattering coefficient, backscattering fraction, absorption coefficient and single scattering albedo at the wavelength of 550 nm were 7.9 (4.4) 1/Mm, 0.13 (0.12), 0.74 (0.35) 1/Mm and 0.92 (0.93), respectively. We observed clear seasonal cycles in these variables, the scattering coefficient having high values during summer and low in fall, and absorption coefficient having high values during winter and low in fall. We found that the high values of the absorption coefficient and low values of the single scattering albedo were related to continental air masses from lower latitudes. These aerosols can induce an additional effect on the surface albedo and melting of snow. We observed the signal of the Arctic haze in marine (northern) air masses during March and April. The haze increased the value of the absorption coefficient by almost 80% and that of the scattering coefficient by about 50% compared with the annual-average values. We did not observe any long-term trend in the scattering coefficient, while our analysis showed a clear decreasing trend in the backscattering fraction and scattering Ångström exponent during winter. We also observed clear relationship with temperature and aerosol scattering coefficient. We will present also how these different features affects to aerosol direct radiative forcing.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C21G1187P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C21G1187P"><span>Spatial and Temporal Means and Variability of Arctic Sea Ice Climate Indicators from Satellite Data</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peng, G.; Meier, W.; Bliss, A. C.; Steele, M.; Dickinson, S.</p> <p>2017-12-01</p> <p>Arctic sea ice has been undergoing rapid and accelerated loss since satellite-based measurements became available in late 1970s, especially the summer ice coverage. For the Arctic as a whole, the long-term trend for the annual sea ice extent (SIE) minimum is about -13.5±2.93 % per decade change relative to the 1979-2015 climate average, while the trends of the annual SIE minimum for the local regions can range from 0 to up to -42 % per decade. This presentation aims to examine and baseline spatial and temporal means and variability of Arctic sea ice climate indicators, such as the annual SIE minimum and maximum, snow/ice melt onset, etc., from a consistent, inter-calibrated, long-term time series of remote sensing sea ice data for understanding regional vulnerability and monitoring ice state for climate adaptation and risk mitigation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4886642','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4886642"><span>Climatic change controls productivity variation in global grasslands</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gao, Qingzhu; Zhu, Wenquan; Schwartz, Mark W.; Ganjurjav, Hasbagan; Wan, Yunfan; Qin, Xiaobo; Ma, Xin; Williamson, Matthew A.; Li, Yue</p> <p>2016-01-01</p> <p>Detection and identification of the impacts of climate change on ecosystems have been core issues in climate change research in recent years. In this study, we compared average annual values of the normalized difference vegetation index (NDVI) with theoretical net primary productivity (NPP) values based on temperature and precipitation to determine the effect of historic climate change on global grassland productivity from 1982 to 2011. Comparison of trends in actual productivity (NDVI) with climate-induced potential productivity showed that the trends in average productivity in nearly 40% of global grassland areas have been significantly affected by climate change. The contribution of climate change to variability in grassland productivity was 15.2–71.2% during 1982–2011. Climate change contributed significantly to long-term trends in grassland productivity mainly in North America, central Eurasia, central Africa, and Oceania; these regions will be more sensitive to future climate change impacts. The impacts of climate change on variability in grassland productivity were greater in the Western Hemisphere than the Eastern Hemisphere. Confirmation of the observed trends requires long-term controlled experiments and multi-model ensembles to reduce uncertainties and explain mechanisms. PMID:27243565</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22833269','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22833269"><span>Variability in solar radiation and temperature explains observed patterns and trends in tree growth rates across four tropical forests.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dong, Shirley Xiaobi; Davies, Stuart J; Ashton, Peter S; Bunyavejchewin, Sarayudh; Supardi, M N Nur; Kassim, Abd Rahman; Tan, Sylvester; Moorcroft, Paul R</p> <p>2012-10-07</p> <p>The response of tropical forests to global climate variability and change remains poorly understood. Results from long-term studies of permanent forest plots have reported different, and in some cases opposing trends in tropical forest dynamics. In this study, we examined changes in tree growth rates at four long-term permanent tropical forest research plots in relation to variation in solar radiation, temperature and precipitation. Temporal variation in the stand-level growth rates measured at five-year intervals was found to be positively correlated with variation in incoming solar radiation and negatively related to temporal variation in night-time temperatures. Taken alone, neither solar radiation variability nor the effects of night-time temperatures can account for the observed temporal variation in tree growth rates across sites, but when considered together, these two climate variables account for most of the observed temporal variability in tree growth rates. Further analysis indicates that the stand-level response is primarily driven by the responses of smaller-sized trees (less than 20 cm in diameter). The combined temperature and radiation responses identified in this study provide a potential explanation for the conflicting patterns in tree growth rates found in previous studies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29245035','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29245035"><span>Multiple long-term trends and trend reversals dominate environmental conditions in a man-made freshwater reservoir.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Znachor, Petr; Nedoma, Jiří; Hejzlar, Josef; Seďa, Jaromír; Kopáček, Jiří; Boukal, David; Mrkvička, Tomáš</p> <p>2018-05-15</p> <p>Man-made reservoirs are common across the world and provide a wide range of ecological services. Environmental conditions in riverine reservoirs are affected by the changing climate, catchment-wide processes and manipulations with the water level, and water abstraction from the reservoir. Long-term trends of environmental conditions in reservoirs thus reflect a wider range of drivers in comparison to lakes, which makes the understanding of reservoir dynamics more challenging. We analysed a 32-year time series of 36 environmental variables characterising weather, land use in the catchment, reservoir hydrochemistry, hydrology and light availability in the small, canyon-shaped Římov Reservoir in the Czech Republic to detect underlying trends, trend reversals and regime shifts. To do so, we fitted linear and piecewise linear regression and a regime shift model to the time series of mean annual values of each variable and to principal components produced by Principal Component Analysis. Models were weighted and ranked using Akaike information criterion and the model selection approach. Most environmental variables exhibited temporal changes that included time-varying trends and trend reversals. For instance, dissolved organic carbon showed a linear increasing trend while nitrate concentration or conductivity exemplified trend reversal. All trend reversals and cessations of temporal trends in reservoir hydrochemistry (except total phosphorus concentrations) occurred in the late 1980s and during 1990s as a consequence of dramatic socioeconomic changes. After a series of heavy rains in the late 1990s, an administrative decision to increase the flood-retention volume of the reservoir resulted in a significant regime shift in reservoir hydraulic conditions in 1999. Our analyses also highlight the utility of the model selection framework, based on relatively simple extensions of linear regression, to describe temporal trends in reservoir characteristics. This approach can provide a solid basis for a better understanding of processes in freshwater reservoirs. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4371967','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4371967"><span>Climate change in the Fertile Crescent and implications of the recent Syrian drought</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kelley, Colin P.; Mohtadi, Shahrzad; Cane, Mark A.; Seager, Richard; Kushnir, Yochanan</p> <p>2015-01-01</p> <p>Before the Syrian uprising that began in 2011, the greater Fertile Crescent experienced the most severe drought in the instrumental record. For Syria, a country marked by poor governance and unsustainable agricultural and environmental policies, the drought had a catalytic effect, contributing to political unrest. We show that the recent decrease in Syrian precipitation is a combination of natural variability and a long-term drying trend, and the unusual severity of the observed drought is here shown to be highly unlikely without this trend. Precipitation changes in Syria are linked to rising mean sea-level pressure in the Eastern Mediterranean, which also shows a long-term trend. There has been also a long-term warming trend in the Eastern Mediterranean, adding to the drawdown of soil moisture. No natural cause is apparent for these trends, whereas the observed drying and warming are consistent with model studies of the response to increases in greenhouse gases. Furthermore, model studies show an increasingly drier and hotter future mean climate for the Eastern Mediterranean. Analyses of observations and model simulations indicate that a drought of the severity and duration of the recent Syrian drought, which is implicated in the current conflict, has become more than twice as likely as a consequence of human interference in the climate system. PMID:25733898</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25733898','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25733898"><span>Climate change in the Fertile Crescent and implications of the recent Syrian drought.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kelley, Colin P; Mohtadi, Shahrzad; Cane, Mark A; Seager, Richard; Kushnir, Yochanan</p> <p>2015-03-17</p> <p>Before the Syrian uprising that began in 2011, the greater Fertile Crescent experienced the most severe drought in the instrumental record. For Syria, a country marked by poor governance and unsustainable agricultural and environmental policies, the drought had a catalytic effect, contributing to political unrest. We show that the recent decrease in Syrian precipitation is a combination of natural variability and a long-term drying trend, and the unusual severity of the observed drought is here shown to be highly unlikely without this trend. Precipitation changes in Syria are linked to rising mean sea-level pressure in the Eastern Mediterranean, which also shows a long-term trend. There has been also a long-term warming trend in the Eastern Mediterranean, adding to the drawdown of soil moisture. No natural cause is apparent for these trends, whereas the observed drying and warming are consistent with model studies of the response to increases in greenhouse gases. Furthermore, model studies show an increasingly drier and hotter future mean climate for the Eastern Mediterranean. Analyses of observations and model simulations indicate that a drought of the severity and duration of the recent Syrian drought, which is implicated in the current conflict, has become more than twice as likely as a consequence of human interference in the climate system.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PNAS..112.3241K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PNAS..112.3241K"><span>Climate change in the Fertile Crescent and implications of the recent Syrian drought</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kelley, Colin P.; Mohtadi, Shahrzad; Cane, Mark A.; Seager, Richard; Kushnir, Yochanan</p> <p>2015-03-01</p> <p>Before the Syrian uprising that began in 2011, the greater Fertile Crescent experienced the most severe drought in the instrumental record. For Syria, a country marked by poor governance and unsustainable agricultural and environmental policies, the drought had a catalytic effect, contributing to political unrest. We show that the recent decrease in Syrian precipitation is a combination of natural variability and a long-term drying trend, and the unusual severity of the observed drought is here shown to be highly unlikely without this trend. Precipitation changes in Syria are linked to rising mean sea-level pressure in the Eastern Mediterranean, which also shows a long-term trend. There has been also a long-term warming trend in the Eastern Mediterranean, adding to the drawdown of soil moisture. No natural cause is apparent for these trends, whereas the observed drying and warming are consistent with model studies of the response to increases in greenhouse gases. Furthermore, model studies show an increasingly drier and hotter future mean climate for the Eastern Mediterranean. Analyses of observations and model simulations indicate that a drought of the severity and duration of the recent Syrian drought, which is implicated in the current conflict, has become more than twice as likely as a consequence of human interference in the climate system.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRC..120.1527W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRC..120.1527W"><span>Evidence for multidecadal variability in US extreme sea level records</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wahl, Thomas; Chambers, Don P.</p> <p>2015-03-01</p> <p>We analyze a set of 20 tide gauge records covering the contiguous United States (US) coastline and the period from 1929 to 2013 to identify long-term trends and multidecadal variations in extreme sea levels (ESLs) relative to changes in mean sea level (MSL). Different data sampling and analysis techniques are applied to test the robustness of the results against the selected methodology. Significant but small long-term trends in ESLs above/below MSL are found at individual sites along most coastline stretches, but are mostly confined to the southeast coast and the winter season when storm surges are primarily driven by extratropical cyclones. We identify six regions with broadly coherent and considerable multidecadal ESL variations unrelated to MSL changes. Using a quasi-nonstationary extreme value analysis, we show that the latter would have caused variations in design relevant return water levels (50-200 year return periods) ranging from ˜10 cm to as much as 110 cm across the six regions. The results raise questions as to the applicability of the "MSL offset method," assuming that ESL changes are primarily driven by changes in MSL without allowing for distinct long-term trends or low-frequency variations. Identifying the coherent multidecadal ESL variability is crucial in order to understand the physical driving factors. Ultimately, this information must be included into coastal design and adaptation processes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?direntryid=315590&keyword=cmaq&acttype=product&timstype=journal&timssubtypeid=+&deid=&epanumber=&ntisid=&archivestatus=both&ombcat=any&datebegincreated=&dateendcreated=&datebeginpublishedpresented=&dateendpublishedpresented=&datebeginupdated=&dateendupdated=&datebegincompleted=&dateendcompleted=&view=citation%20&personid=&role=any&journalid=&publisherid=&sortby=fy&count=25&cfid=77182256&cftoken=94527145','PESTICIDES'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?direntryid=315590&keyword=cmaq&acttype=product&timstype=journal&timssubtypeid=+&deid=&epanumber=&ntisid=&archivestatus=both&ombcat=any&datebegincreated=&dateendcreated=&datebeginpublishedpresented=&dateendpublishedpresented=&datebeginupdated=&dateendupdated=&datebegincompleted=&dateendcompleted=&view=citation%20&personid=&role=any&journalid=&publisherid=&sortby=fy&count=25&cfid=77182256&cftoken=94527145"><span>Assessment of the effects of horizontal grid resolution on long ...</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>The objective of this study is to determine the adequacy of using a relatively coarse horizontal resolution (i.e. 36 km) to simulate long-term trends of pollutant concentrations and radiation variables with the coupled WRF-CMAQ model. WRF-CMAQ simulations over the continental United State are performed over the 2001 to 2010 time period at two different horizontal resolutions of 12 and 36 km. Both simulations used the same emission inventory and model configurations. Model results are compared both in space and time to assess the potential weaknesses and strengths of using coarse resolution in long-term air quality applications. The results show that the 36 km and 12 km simulations are comparable in terms of trends analysis for both pollutant concentrations and radiation variables. The advantage of using the coarser 36 km resolution is a significant reduction of computational cost, time and storage requirement which are key considerations when performing multiple years of simulations for trend analysis. However, if such simulations are to be used for local air quality analysis, finer horizontal resolution may be beneficial since it can provide information on local gradients. In particular, divergences between the two simulations are noticeable in urban, complex terrain and coastal regions. The National Exposure Research Laboratory’s Atmospheric Modeling Division (AMAD) conducts research in support of EPA’s mission to protect human health and the environment.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70047945','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70047945"><span>Implications of multi-scale sea level and climate variability for coastal resources</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Karamperidou, Christina; Engel, Victor; Lall, Upmanu; Stabenau, Erik; Smith, Thomas J.</p> <p>2013-01-01</p> <p>While secular changes in regional sea levels and their implications for coastal zone management have been studied extensively, less attention is being paid to natural fluctuations in sea levels, whose interaction with a higher mean level could have significant impacts on low-lying areas, such as wetlands. Here, the long record of sea level at Key West, FL is studied in terms of both the secular trend and the multi-scale sea level variations. This analysis is then used to explore implications for the Everglades National Park (ENP), which is recognized internationally for its ecological significance, and is the site of the largest wetland restoration project in the world. Very shallow topographic gradients (3–6 cm per km) make the region susceptible to small changes in sea level. Observations of surface water levels from a monitoring network within ENP exhibit both the long-term trends and the interannual-to-(multi)decadal variability that are observed in the Key West record. Water levels recorded at four long-term monitoring stations within ENP exhibit increasing trends approximately equal to or larger than the long-term trend at Key West. Time- and frequency-domain analyses highlight the potential influence of climate mechanisms, such as the El Niño/Southern Oscillation and the North Atlantic Oscillation (NAO), on Key West sea levels and marsh water levels, and the potential modulation of their influence by the background state of the North Atlantic Sea Surface Temperatures. In particular, the Key West sea levels are found to be positively correlated with the NAO index, while the two series exhibit high spectral power during the transition to a cold Atlantic Multidecadal Oscillation (AMO). The correlation between the Key West sea levels and the NINO3 Index reverses its sign in coincidence with a reversal of the AMO phase. Water levels in ENP are also influenced by precipitation and freshwater releases from the northern boundary of the Park. The analysis of both climate variability and climate change in such wetlands is needed to inform management practices in coastal wetland zones around the world.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017CSR...151....1S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017CSR...151....1S"><span>Timescales for determining temperature and dissolved oxygen trends in the Long Island Sound (LIS) estuary</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Staniec, Allison; Vlahos, Penny</p> <p>2017-12-01</p> <p>Long-term time series represent a critical part of the oceanographic community's efforts to discern natural and anthropogenically forced variations in the environment. They provide regular measurements of climate relevant indicators including temperature, oxygen concentrations, and salinity. When evaluating time series, it is essential to isolate long-term trends from autocorrelation in data and noise due to natural variability. Herein we apply a statistical approach, well-established in atmospheric time series, to key parameters in the U.S. east coast's Long Island Sound estuary (LIS). Analysis shows that the LIS time series (established in the early 1990s) is sufficiently long to detect significant trends in physical-chemical parameters including temperature (T) and dissolved oxygen (DO). Over the last two decades, overall (combined surface and deep) LIS T has increased at an average rate of 0.08 ± 0.03 °C yr-1 while overall DO has dropped at an average rate of 0.03 ± 0.01 mg L-1yr-1 since 1994 at the 95% confidence level. This trend is notably faster than the global open ocean T trend (0.01 °C yr-1), as might be expected for a shallower estuarine system. T and DO trends were always significant for the existing time series using four month data increments. Rates of change of DO and T in LIS are strongly correlated and the rate of decrease of DO concentrations is consistent with the expected reduced solubility of DO at these higher temperatures. Thus, changes in T alone, across decadal timescales can account for between 33 and 100% of the observed decrease in DO. This has significant implications for other dissolved gases and the long-term management of LIS hypoxia.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/1001085','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/1001085"><span>Long-term trends of bloater (Coregonus hoyi) recruitment in Lake Michigan: evidence for the effect of sex ratio</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bunnell, David B.; Madenjian, Charles P.; Croley, Thomas E.</p> <p>2006-01-01</p> <p>Long-term population trends are generally explained by factors extrinsic (e.g., climate, predation) rather than intrinsic (e.g., genetics, maternal effects) to the population. We sought to understand the long-term population dynamics of an important native Lake Michigan prey fish, the bloaterCoregonus hoyi. Over a 38-year time series, three 10- to 15-year phases occurred (poor, excellent, and then poor recruitment) without high interannual variability within a particular phase. We used dynamic linear models to determine whether extrinsic (winter and spring temperature, alewife predator densities) or intrinsic factors (population egg production, adult condition, adult sex ratio) explained variation in recruitment. Models that included population egg production, sex ratio, winter and spring temperature, and adult bloater condition explained the most variation. Of these variables, sex ratio, which ranged from 47% to 97% female across the time series, consistently had the greatest effect: recruitment declined with female predominance. Including biomass of adult alewife predators in the models did not explain additional variation. Overall our results indicated that bloater recruitment is linked to its sex ratio, but understanding the underlying mechanisms will require additional efforts.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC23D1092Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC23D1092Z"><span>Long-term Trends and Variability of Eddy Activities in the South China Sea</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, M.; von Storch, H.</p> <p>2017-12-01</p> <p>For constructing empirical downscaling models and projecting possible future states of eddy activities in the South China Sea (SCS), long-term statistical characteristics of the SCS eddy are needed. We use a daily global eddy-resolving model product named STORM covering the period of 1950-2010. This simulation has employed the MPI-OM model with a mean horizontal resolution of 10km and been driven by the NCEP reanalysis-1 data set. An eddy detection and tracking algorithm operating on the gridded sea surface height anomaly (SSHA) fields was developed. A set of parameters for the criteria in the SCS are determined through sensitivity tests. Our method detected more than 6000 eddy tracks in the South China Sea. For all of them, eddy diameters, track length, eddy intensity, eddy lifetime and eddy frequency were determined. The long-term trends and variability of those properties also has been derived. Most of the eddies propagate westward. Nearly 100 eddies travel longer than 1000km, and over 800 eddies have a lifespan of more than 2 months. Furthermore, for building the statistical empirical model, the relationship between the SCS eddy statistics and the large-scale atmospheric and oceanic phenomena has been investigated.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4611663','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4611663"><span>Long-term reliability of the Athabasca River (Alberta, Canada) as the water source for oil sands mining</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sauchyn, David J.; St-Jacques, Jeannine-Marie; Luckman, Brian H.</p> <p>2015-01-01</p> <p>Exploitation of the Alberta oil sands, the world’s third-largest crude oil reserve, requires fresh water from the Athabasca River, an allocation of 4.4% of the mean annual flow. This allocation takes into account seasonal fluctuations but not long-term climatic variability and change. This paper examines the decadal-scale variability in river discharge in the Athabasca River Basin (ARB) with (i) a generalized least-squares (GLS) regression analysis of the trend and variability in gauged flow and (ii) a 900-y tree-ring reconstruction of the water-year flow of the Athabasca River at Athabasca, Alberta. The GLS analysis removes confounding transient trends related to the Pacific Decadal Oscillation (PDO) and Pacific North American mode (PNA). It shows long-term declining flows throughout the ARB. The tree-ring record reveals a larger range of flows and severity of hydrologic deficits than those captured by the instrumental records that are the basis for surface water allocation. It includes periods of sustained low flow of multiple decades in duration, suggesting the influence of the PDO and PNA teleconnections. These results together demonstrate that low-frequency variability must be considered in ARB water allocation, which has not been the case. We show that the current and projected surface water allocations from the Athabasca River for the exploitation of the Alberta oil sands are based on an untenable assumption of the representativeness of the short instrumental record. PMID:26392554</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUSMGC41B..03G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUSMGC41B..03G"><span>Implementation of a Time Series Analysis for the Assessment of the Role of Climate Variability in a Post-Disturbance Savanna System</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gibbes, C.; Southworth, J.; Waylen, P. R.</p> <p>2013-05-01</p> <p>How do climate variability and climate change influence vegetation cover and vegetation change in savannas? A landscape scale investigation of the effect of changes in precipitation on vegetation is undertaken through the employment of a time series analysis. The multi-national study region is located within the Kavango-Zambezi region, and is delineated by the Okavango, Kwando, and Zambezi watersheds. A mean-variance time-series analysis quantifies vegetation dynamics and characterizes vegetation response to climate. The spatially explicit approach used to quantify the persistence of vegetation productivity permits the extraction of information regarding long term climate-landscape dynamics. Results show a pattern of reduced mean annual precipitation and increased precipitation variability across key social and ecological areas within the study region. Despite decreased mean annual precipitation since the mid to late 1970's vegetation trends predominantly indicate increasing biomass. The limited areas which have diminished vegetative cover relate to specific vegetation types, and are associated with declines in precipitation variability. Results indicate that in addition to short term changes in vegetation cover, long term trends in productive biomass are apparent, relate to spatial differences in precipitation variability, and potentially represent shifts vegetation composition. This work highlights the importance of time-series analyses for examining climate-vegetation linkages in a spatially explicit manner within a highly vulnerable region of the world.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20050000442&hterms=heart+disease&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dheart%2Bdisease','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20050000442&hterms=heart+disease&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dheart%2Bdisease"><span>Conventional heart rate variability analysis of ambulatory electrocardiographic recordings fails to predict imminent ventricular fibrillation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vybiral, T.; Glaeser, D. H.; Goldberger, A. L.; Rigney, D. R.; Hess, K. R.; Mietus, J.; Skinner, J. E.; Francis, M.; Pratt, C. M.</p> <p>1993-01-01</p> <p>OBJECTIVES. The purpose of this report was to study heart rate variability in Holter recordings of patients who experienced ventricular fibrillation during the recording. BACKGROUND. Decreased heart rate variability is recognized as a long-term predictor of overall and arrhythmic death after myocardial infarction. It was therefore postulated that heart rate variability would be lowest when measured immediately before ventricular fibrillation. METHODS. Conventional indexes of heart rate variability were calculated from Holter recordings of 24 patients with structural heart disease who had ventricular fibrillation during monitoring. The control group consisted of 19 patients with coronary artery disease, of comparable age and left ventricular ejection fraction, who had nonsustained ventricular tachycardia but no ventricular fibrillation. RESULTS. Heart rate variability did not differ between the two groups, and no consistent trends in heart rate variability were observed before ventricular fibrillation occurred. CONCLUSIONS. Although conventional heart rate variability is an independent long-term predictor of adverse outcome after myocardial infarction, its clinical utility as a short-term predictor of life-threatening arrhythmias remains to be elucidated.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20234056','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20234056"><span>Firearm homicide in Australia, Canada, and New Zealand: what can we learn from long-term international comparisons?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McPhedran, Samara; Baker, Jeanine; Singh, Pooja</p> <p>2011-01-01</p> <p>Although firearm homicide remains a topic of interest within criminological and policy discourse, existing research does not generally undertake longitudinal comparisons between countries. However, cross-country comparisons provide insight into whether "local" trends (e.g., declines in firearm homicide in one particular country) differ from broader, international trends. This in turn can improve knowledge about the role of factors such as policing practices and socioeconomic variables in the incidence of lethal violence using firearms. The current study compares long-term firearm homicide trends in three countries with similar social histories but different legislative regimes: Australia, Canada, and New Zealand. Using negative binomial regression, the study found that the most pronounced decline in firearm homicide over the past two decades occurred in New Zealand. Connections between social disadvantage, policing policy, and violence are discussed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1910131C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1910131C"><span>River-discharge variability and trends in southeastern Central Andes since 1940</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Castino, Fabiana; Bookhagen, Bodo; Strecker, Manfred R.</p> <p>2017-04-01</p> <p>The southern Central Andes in NW Argentina comprise small to medium drainage basins (102-104 km2) particularly sensitive to climate variability. In this area and in contrast to larger drainage basins such as the Amazon or La Plata rivers, floodplains or groundwater reservoirs either do not exist or are small. This reduces their dampening effect on discharge variability. Previous studies highlighted a rapid discharge increase up to 40% in seven years in the southern Central Andes during the 1970s, inferred to have been associated with the global 1976-77 climate shift. To better understand the processes that drive variations in river discharge in this region, we analyze discharge variability on different timescales, relying on four time series of monthly discharge between 1940 and 2015. Since river discharge in this complex mountain environment results in a pronounced non-stationary and non-linear character, we apply the Hilbert-Huang Transform (HHT) to evaluate non-stationary oscillatory modes of variability and trends. An Ensemble Empirical Mode Decomposition (EEMD) analysis revealed that discharge variability in this region can be decomposed in four quasi-periodic, statistically significant oscillatory modes, associated with timescales varying from 1 to ˜20y. In addition, statistically significant long-term trends show increasing discharge during the period between 1940 and 2015, documenting an intensification of the hydrological cycle during this period. Furthermore, time-dependent intrinsic correlation (TDIC) analysis shows that discharge variability is most likely linked to the phases of the Pacific Decadal Oscillation (PDO) at multi-decadal timescales (˜20y) and, to a lesser degree, to the Tropical South Atlantic SST anomaly (TSA) variability at shorter timescales (˜2-5y). Finally, our results suggest that the rapid discharge increased occurred during the 1970s coincides with the periodic enhancement of discharge mainly linked to the rise of the PDO oscillation from the negative to the positive phase in superposition with the long-term increasing trend, further modulated by TSA variability.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AnGeo..36..149T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AnGeo..36..149T"><span>Long-term trends in stratospheric ozone, temperature, and water vapor over the Indian region</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thankamani Akhil Raj, Sivan; Venkat Ratnam, Madineni; Narayana Rao, Daggumati; Venkata Krishna Murthy, Boddam</p> <p>2018-01-01</p> <p>We have investigated the long-term trends in and variabilities of stratospheric ozone, water vapor and temperature over the Indian monsoon region using the long-term data constructed from multi-satellite (Upper Atmosphere Research Satellite (UARS MLS and HALOE, 1993-2005), Aura Microwave Limb Sounder (MLS, 2004-2015), Sounding of the Atmosphere using Broadband Emission Radiometry (SABER, 2002-2015) on board TIMED (Thermosphere Ionosphere Mesosphere Energetics Dynamics)) observations covering the period 1993-2015. We have selected two locations, namely, Trivandrum (8.4° N, 76.9° E) and New Delhi (28° N, 77° E), covering northern and southern parts of the Indian region. We also used observations from another station, Gadanki (13.5° N, 79.2° E), for comparison. A decreasing trend in ozone associated with NOx chemistry in the tropical middle stratosphere is found, and the trend turned to positive in the upper stratosphere. Temperature shows a cooling trend in the stratosphere, with a maximum around 37 km over Trivandrum (-1.71 ± 0.49 K decade-1) and New Delhi (-1.15 ± 0.55 K decade-1). The observed cooling trend in the stratosphere over Trivandrum and New Delhi is consistent with Gadanki lidar observations during 1998-2011. The water vapor shows a decreasing trend in the lower stratosphere and an increasing trend in the middle and upper stratosphere. A good correlation between N2O and O3 is found in the middle stratosphere (˜ 10 hPa) and poor correlation in the lower stratosphere. There is not much regional difference in the water vapor and temperature trends. However, upper stratospheric ozone trends over Trivandrum and New Delhi are different. The trend analysis carried out by varying the initial year has shown significant changes in the estimated trend.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRD..122.7705Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRD..122.7705Z"><span>Evaluating the patterns of spatiotemporal trends of root zone soil moisture in major climate regions in East Asia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zohaib, Muhammad; Kim, Hyunglok; Choi, Minha</p> <p>2017-08-01</p> <p>Root zone soil moisture (RZSM) is a crucial variable in land-atmosphere interactions. Evaluating the spatiotemporal trends and variability patterns of RZSM are essential for discerning the anthropogenic and climate change effects on the regional and global hydrological cycles. In this study, the trends of RZSM, computed by the exponential filter from the European Space Agency's Climate Change Initiative soil moisture, were evaluated in major climate regions of East Asia from 1982 to 2014. Moreover, the trends of RZSM were compared to the trends of precipitation (<fi>P</fi>), skin temperature (<fi>T</fi>skin), and actual evapotranspiration (AET) to investigate how they influence the RZSM trends in each climate region. Drying trends were predominant in arid and continental regions, whereas wetting trends were found in the tropical and temperate regions. The increasing trends of <fi>T</fi>skin and AET cause drying in arid and continental regions, whereas in tropical regions, these cause wetting trends, which might be due to convective <fi>P</fi>. In temperate regions, despite decreasing <fi>P</fi> and increasing <fi>T</fi>skin, the RZSM trend was increasing, attributed to the intensive irrigation activities in these regions. This is probably the first time to analyze the long-term trends of RZSM in different climate regions. Hence, the results of this study will improve our understanding of the regional and global hydrological cycles. Despite certain limitations, the results of this study may be useful for improving and developing climate models and predicting long-term vast scale natural disasters such as drought, dust outbreaks, floods, and heat waves.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JHyd..552..704H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JHyd..552..704H"><span>Climate-driven variability in the occurrence of major floods across North America and Europe</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hodgkins, Glenn A.; Whitfield, Paul H.; Burn, Donald H.; Hannaford, Jamie; Renard, Benjamin; Stahl, Kerstin; Fleig, Anne K.; Madsen, Henrik; Mediero, Luis; Korhonen, Johanna; Murphy, Conor; Wilson, Donna</p> <p>2017-09-01</p> <p>Concern over the potential impact of anthropogenic climate change on flooding has led to a proliferation of studies examining past flood trends. Many studies have analysed annual-maximum flow trends but few have quantified changes in major (25-100 year return period) floods, i.e. those that have the greatest societal impacts. Existing major-flood studies used a limited number of very large catchments affected to varying degrees by alterations such as reservoirs and urbanisation. In the current study, trends in major-flood occurrence from 1961 to 2010 and from 1931 to 2010 were assessed using a very large dataset (>1200 gauges) of diverse catchments from North America and Europe; only minimally altered catchments were used, to focus on climate-driven changes rather than changes due to catchment alterations. Trend testing of major floods was based on counting the number of exceedances of a given flood threshold within a group of gauges. Evidence for significant trends varied between groups of gauges that were defined by catchment size, location, climate, flood threshold and period of record, indicating that generalizations about flood trends across large domains or a diversity of catchment types are ungrounded. Overall, the number of significant trends in major-flood occurrence across North America and Europe was approximately the number expected due to chance alone. Changes over time in the occurrence of major floods were dominated by multidecadal variability rather than by long-term trends. There were more than three times as many significant relationships between major-flood occurrence and the Atlantic Multidecadal Oscillation than significant long-term trends.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.sciencedirect.com/science/article/pii/S002216941730478X','USGSPUBS'); return false;" href="http://www.sciencedirect.com/science/article/pii/S002216941730478X"><span>Climate-driven variability in the occurrence of major floods across North America and Europe</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hodgkins, Glenn A.; Whitfield, Paul H.; Burn, Donald H.; Hannaford, Jamie; Renard, Benjamin; Stahl, Kerstin; Fleig, Anne K.; Madsen, Henrik; Mediero, Luis; Korhonen, Johanna; Murphy, Conor; Wilson, Donna</p> <p>2017-01-01</p> <p>Concern over the potential impact of anthropogenic climate change on flooding has led to a proliferation of studies examining past flood trends. Many studies have analysed annual-maximum flow trends but few have quantified changes in major (25–100 year return period) floods, i.e. those that have the greatest societal impacts. Existing major-flood studies used a limited number of very large catchments affected to varying degrees by alterations such as reservoirs and urbanisation. In the current study, trends in major-flood occurrence from 1961 to 2010 and from 1931 to 2010 were assessed using a very large dataset (>1200 gauges) of diverse catchments from North America and Europe; only minimally altered catchments were used, to focus on climate-driven changes rather than changes due to catchment alterations. Trend testing of major floods was based on counting the number of exceedances of a given flood threshold within a group of gauges. Evidence for significant trends varied between groups of gauges that were defined by catchment size, location, climate, flood threshold and period of record, indicating that generalizations about flood trends across large domains or a diversity of catchment types are ungrounded. Overall, the number of significant trends in major-flood occurrence across North America and Europe was approximately the number expected due to chance alone. Changes over time in the occurrence of major floods were dominated by multidecadal variability rather than by long-term trends. There were more than three times as many significant relationships between major-flood occurrence and the Atlantic Multidecadal Oscillation than significant long-term trends.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AtmRe.169..301L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AtmRe.169..301L"><span>Long-term trends and variability of total and extreme precipitation in Thailand</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Limsakul, Atsamon; Singhruck, Patama</p> <p>2016-03-01</p> <p>Based on quality-controlled daily station data, long-term trends and variability of total and extreme precipitation indices during 1955-2014 were examined for Thailand. An analysis showed that while precipitation events have been less frequent across most of Thailand, they have become more intense. Moreover, the indices measuring the magnitude of intense precipitation events indicate a trend toward wetter conditions, with heavy precipitation contributing a greater fraction to annual totals. One consequence of this change is the increased frequency and severity of flash floods as recently evidenced in many parts of Thailand. On interannual-to-interdecadal time scales, significant relationships between variability of precipitation indices and the indices for the state of El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) were found. These results provide additional evidence that large-scale climate phenomena in the Pacific Ocean are remote drivers of variability in Thailand's total and extreme precipitation. Thailand tended to have greater amounts of precipitation and more extreme events during La Niña years and the PDO cool phase, and vice versa during El Niño years and the PDO warm phase. Another noteworthy finding is that in 2011 Thailand experienced extensive flooding in a year characterized by exceptionally extreme precipitation events. Our results are consistent with the regional studies for the Asia-Pacific Network. However, this study provides a more detailed picture of coherent trends at a station scale and documents changes that have occurred in the twenty-first century, both of which help to inform decisions concerning effective management strategies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PolSc..10..199T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PolSc..10..199T"><span>Relationship between the Arctic oscillation and surface air temperature in multi-decadal time-scale</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tanaka, Hiroshi L.; Tamura, Mina</p> <p>2016-09-01</p> <p>In this study, a simple energy balance model (EBM) was integrated in time, considering a hypothetical long-term variability in ice-albedo feedback mimicking the observed multi-decadal temperature variability. A natural variability was superimposed on a linear warming trend due to the increasing radiative forcing of CO2. The result demonstrates that the superposition of the natural variability and the background linear trend can offset with each other to show the warming hiatus for some period. It is also stressed that the rapid warming during 1970-2000 can be explained by the superposition of the natural variability and the background linear trend at least within the simple model. The key process of the fluctuating planetary albedo in multi-decadal time scale is investigated using the JRA-55 reanalysis data. It is found that the planetary albedo increased for 1958-1970, decreased for 1970-2000, and increased for 2000-2012, as expected by the simple EBM experiments. The multi-decadal variability in the planetary albedo is compared with the time series of the AO mode and Barents Sea mode of surface air temperature. It is shown that the recent AO negative pattern showing warm Arctic and cold mid-latitudes is in good agreement with planetary albedo change indicating negative anomaly in high latitudes and positive anomaly in mid-latitudes. Moreover, the Barents Sea mode with the warm Barents Sea and cold mid-latitudes shows long-term variability similar to planetary albedo change. Although further studies are needed, the natural variabilities of both the AO mode and Barents Sea mode indicate some possible link to the planetary albedo as suggested by the simple EBM to cause the warming hiatus in recent years.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.9787K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.9787K"><span>Future changes of interannual variation of the Asian summer monsoon precipitation using the CMIP5</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kamizawa, Nozomi; Takahashi, Hiroshi G.</p> <p>2015-04-01</p> <p>The Asian summer monsoon (ASM) region is one of the most populated areas in the world. Since the life of people who live in the region and the industry are strongly dependent on the ASM precipitation, it is interested that how it would change under the circumstance of global warming. Many studies have reported that the mean ASM precipitation would increase by comparing the CMIP models' climatology. Although the changes in mean climate are important, the long-term changes of interannual variability in precipitation are also significant. This study investigated the long-term trend of interannual precipitation variation over the ASM region by using 22 CMIP5 models. The RCP4.5 scenario was used. To investigate the long-term trend of the interannual variation of the ASM precipitation, each model data was recreated to 2.5 degree resolution and a running standard deviation for 21 years of June-July-August (JJA) precipitation were calculated. Next, we created the coefficient variation (CV) by dividing the running standard deviation by the mean JJA precipitation. Then we run a Mann-Kendall test for the CV at each grid. There were more areas which were indicated a statistically significant increasing trend than a decreasing trend in the ASM region. 40.6% of the region indicated an increasing trend in the future. On the other hand, 16.8% of the area was indicated to have a decreasing trend. It was also common in the global scale that the there were more areas that indicated an increasing trend than a decreasing trend. We also divided the area into three groups: land, shore and open ocean. In the ASM region, the shore areas particularly had an increasing CV trend. To investigate the long-term changes of the interannual variability of the precipitation and the atmospheric circulation over the ASM region, we conducted a composite analysis for the five wettest and driest years for two periods: the early 21st century (2007-2031) and the late 21st century (2076-2100). The special patterns of the interannual variation of the precipitation and the atmospheric circulation between the two periods had differed only slightly. A positive deviation precipitation band with a cyclonic circulation was recognized from across the Bay of Bengal to the equatorial Northwest Pacific. The none-big-difference of the patterns may suggest that interannual variation in the ASM region would increase not because the pattern changes, but because the pattern's strength gets stronger or its frequency gets higher.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRG..123..807W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRG..123..807W"><span>Trends and Variability in Temperature Sensitivity of Lilac Flowering Phenology</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Huanjiong; Dai, Junhu; Rutishauser, This; Gonsamo, Alemu; Wu, Chaoyang; Ge, Quansheng</p> <p>2018-03-01</p> <p>The responses of plant phenology to temperature variability have many consequences for ecological processes, agriculture, forestry, and human health. Temperature sensitivity (ST) of phenology could measure how and to what degree plant could phenologically track climate change. The long-term trends and spatial patterns in ST have been well studied for vegetative phenology such as leaf unfolding, but trends to be expected for reproductive phenology in the future remain unknown. Here we investigate trends and factors driving the temporal variation of ST of first bloom date (FBD). Using the long-term FBD records during 1963-2013 for common lilac (Syringa vulgaris) from 613 stations in Europe, we compared changes in ST from the beginning to the end of the study period. The Spearman partial correlations were used to assess the importance of four influencing factors. The results showed that the temporal changes in ST of FBD varied considerably among time scales. Mean ST decreased significantly by 0.92 days °C-1 from 1963-1972 to 2004-2013 (P < 0.01), but remained stable from 1963-1987 to 1989-2013. The strength of FBD and temperature relationship, the spring temperature variance, and winter chill all impact ST in an expected way at most stations. No consistent responses of ST on photoperiod were found. Our results imply that the trends and variability in ST of flowering phenology are driving by multiple factors and impacted by time scales. Continued efforts are still needed to further examine the flowering-temperature relationship for other plant species in other climates and environments using similar methods to our study.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5363829','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5363829"><span>Variability in age and size at maturation, reproductive longevity, and long-term growth dynamics for Kemp's ridley sea turtles in the Gulf of Mexico</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Goshe, Lisa R.; Coggins, Lewis; Shaver, Donna J.; Higgins, Ben; Landry, Andre M.; Bailey, Rhonda</p> <p>2017-01-01</p> <p>Effective management of protected sea turtle populations requires knowledge not only of mean values for demographic and life-history parameters, but also temporal and spatial trends, variability, and underlying causes. For endangered Kemp’s ridley sea turtles (Lepidochelys kempii), the need for baseline information of this type has been emphasized during attempts to understand causes underlying the recent truncation in the recovery trajectory for nesting females. To provide insight into variability in age and size at sexual maturation (ASM and SSM) and long-term growth patterns likely to influence population trends, we conducted skeletochronological analysis of humerus bones from 333 Kemp’s ridleys stranded throughout the Gulf of Mexico (GOM) from 1993 to 2010. Ranges of possible ASMs (6.8 to 21.8 yr) and SSMs (53.3 to 68.3 cm straightline carapace length (SCL)) estimated using the “rapprochement” skeletal growth mark associated with maturation were broad, supporting incorporation of a maturation schedule in Kemp’s ridley population models. Mean ASMs estimated from rapprochement and by fitting logistic, generalized additive mixed, and von Bertalanffy growth models to age and growth data ranged from 11 to 13 yr; confidence intervals for the logistic model predicted maturation of 95% of the population between 11.9 and 14.8 yr. Early juvenile somatic growth rates in the GOM were greater than those previously reported for the Atlantic, indicating potential for differences in maturation trajectories between regions. Finally, long-term, significant decreases in somatic growth response were found for both juveniles and adults, which could influence recruitment to the reproductive population and observed nesting population trends. PMID:28333937</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28333937','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28333937"><span>Variability in age and size at maturation, reproductive longevity, and long-term growth dynamics for Kemp's ridley sea turtles in the Gulf of Mexico.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Avens, Larisa; Goshe, Lisa R; Coggins, Lewis; Shaver, Donna J; Higgins, Ben; Landry, Andre M; Bailey, Rhonda</p> <p>2017-01-01</p> <p>Effective management of protected sea turtle populations requires knowledge not only of mean values for demographic and life-history parameters, but also temporal and spatial trends, variability, and underlying causes. For endangered Kemp's ridley sea turtles (Lepidochelys kempii), the need for baseline information of this type has been emphasized during attempts to understand causes underlying the recent truncation in the recovery trajectory for nesting females. To provide insight into variability in age and size at sexual maturation (ASM and SSM) and long-term growth patterns likely to influence population trends, we conducted skeletochronological analysis of humerus bones from 333 Kemp's ridleys stranded throughout the Gulf of Mexico (GOM) from 1993 to 2010. Ranges of possible ASMs (6.8 to 21.8 yr) and SSMs (53.3 to 68.3 cm straightline carapace length (SCL)) estimated using the "rapprochement" skeletal growth mark associated with maturation were broad, supporting incorporation of a maturation schedule in Kemp's ridley population models. Mean ASMs estimated from rapprochement and by fitting logistic, generalized additive mixed, and von Bertalanffy growth models to age and growth data ranged from 11 to 13 yr; confidence intervals for the logistic model predicted maturation of 95% of the population between 11.9 and 14.8 yr. Early juvenile somatic growth rates in the GOM were greater than those previously reported for the Atlantic, indicating potential for differences in maturation trajectories between regions. Finally, long-term, significant decreases in somatic growth response were found for both juveniles and adults, which could influence recruitment to the reproductive population and observed nesting population trends.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.4447J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.4447J"><span>Revisiting sea level changes in the North Sea during the Anthropocene</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jensen, Jürgen; Dangendorf, Sönke; Wahl, Thomas; Niehüser, Sebastian</p> <p>2016-04-01</p> <p>The North Sea is one of the best instrumented ocean basins in the world. Here we revisit sea level changes in the North Sea region from tide gauges, satellite altimetry, hydrographic profiles and ocean reanalysis data from the beginning of the 19th century to present. This includes an overview of the sea level chapter of the North Sea Climate Change Assessment (NOSCCA) complemented by results from more recent investigations. The estimates of long-term changes from tide gauge records are significantly affected by vertical land motion (VLM), which is related to both the large-scale viscoelastic response of the solid earth to ice melting since the last deglaciation and local effects. Removing VLM (estimated from various data sources such as GPS, tide gauge minus altimetry and GIA) significantly reduces the spatial variability of long-term trends in the basin. VLM corrected tide gauge records suggest a transition from relatively moderate changes in the 19th century towards modern trends of roughly 1.5 mm/yr during the 20th century. Superimposed on the long-term changes there is a considerable inter-annual to multi-decadal variability. On inter-annual timescales this variability mainly reflects the barotropic response of the ocean to atmospheric forcing with the inverted barometer effect dominating along the UK and Norwegian coastlines and wind forcing controlling the southeastern part of the basin. The decadal variability is mostly remotely forced and dynamically linked to the North Atlantic via boundary waves in response to long-shore winds along the continental slope. These findings give valuable information about the required horizontal resolution of ocean models and the necessary boundary conditions and are therefore important for the dynamical downscaling of sea level projections for the North Sea coastlines.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1349031-climate-change-fertile-crescent-implications-recent-syrian-drought','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1349031-climate-change-fertile-crescent-implications-recent-syrian-drought"><span>Climate change in the Fertile Crescent and implications of the recent Syrian drought</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Kelley, Colin P.; Mohtadi, Shahrzad; Cane, Mark A.; ...</p> <p>2015-03-02</p> <p>Before the Syrian uprising that began in 2011, the greater Fertile Crescent experienced the most severe drought in the instrumental record. For Syria, a country marked by poor governance and unsustainable agricultural and environmental policies, the drought had a catalytic effect, contributing to political unrest. In this paper, we show that the recent decrease in Syrian precipitation is a combination of natural variability and a long-term drying trend, and the unusual severity of the observed drought is here shown to be highly unlikely without this trend. Precipitation changes in Syria are linked to rising mean sea-level pressure in the Easternmore » Mediterranean, which also shows a long-term trend. There has been also a long-term warming trend in the Eastern Mediterranean, adding to the drawdown of soil moisture. No natural cause is apparent for these trends, whereas the observed drying and warming are consistent with model studies of the response to increases in greenhouse gases. Furthermore, model studies show an increasingly drier and hotter future mean climate for the Eastern Mediterranean. Finally, analyses of observations and model simulations indicate that a drought of the severity and duration of the recent Syrian drought, which is implicated in the current conflict, has become more than twice as likely as a consequence of human interference in the climate system.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JPhCS.972a2003W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JPhCS.972a2003W"><span>Applying Metrological Techniques to Satellite Fundamental Climate Data Records</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Woolliams, Emma R.; Mittaz, Jonathan PD; Merchant, Christopher J.; Hunt, Samuel E.; Harris, Peter M.</p> <p>2018-02-01</p> <p>Quantifying long-term environmental variability, including climatic trends, requires decadal-scale time series of observations. The reliability of such trend analysis depends on the long-term stability of the data record, and understanding the sources of uncertainty in historic, current and future sensors. We give a brief overview on how metrological techniques can be applied to historical satellite data sets. In particular we discuss the implications of error correlation at different spatial and temporal scales and the forms of such correlation and consider how uncertainty is propagated with partial correlation. We give a form of the Law of Propagation of Uncertainties that considers the propagation of uncertainties associated with common errors to give the covariance associated with Earth observations in different spectral channels.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000GeoRL..27.2213B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000GeoRL..27.2213B"><span>Variability of total ozone at Arosa, Switzerland, since 1931 related to atmospheric circulation indices</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brönnimann, S.; Luterbacher, J.; Schmutz, C.; Wanner, H.; Staehelin, J.</p> <p>2000-08-01</p> <p>Atmospheric circulation determines to a considerable extent the variability of lower stratospheric ozone and can modulate its long-term trends in Europe and the North Atlantic Region. Due to dynamical stratosphere-troposphere coupling, important features of the variability of the surface pressure field are reflected in the long-term total ozone record from Arosa, Switzerland. Significant (p<0.01) correlations between total ozone and different atmospheric circulation indices (NAOI, AOI, EU1, EU2) are found in all months except for April, June, July, and November for the period 1931 to 1997. An analysis of geopotential heights for the period 1958 to 1997 shows that these circulation anomaly patterns have upper tropospheric features over the North Atlantic-European sector that are consistent with a dynamical influence on total ozone.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JASTP.167...23N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JASTP.167...23N"><span>Seasonal, interannual and long-term variabilities and tendencies of water vapour in the upper stratosphere and mesospheric region over tropics (30°N-30°S)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nath, Oindrila; Sridharan, S.; Naidu, C. V.</p> <p>2018-01-01</p> <p>Tropical water vapour volume mixing ratio (WVMR) data for October 2004-September 2015 obtained from the Microwave Limb Sounder are used to study its long-term variabilities and tendencies in the height region 12.1-0.002 hPa. Above 0.01 hPa, the WVMR shows minimum March-May and September-November (∼0.7-0.8 ppmv) and maximum during June-August. It shows a large interannual variability at 31-64 km. The results from multivariate regression analysis show an increasing trend with maximum value of ∼0.045 ppmv/yr at 1.21-0.41 hPa. It shows a significant negative solar cycle response at mesospheric heights.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890020545','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890020545"><span>Observations of, and sources of the spatial and temporal variability of ozone in the middle atmosphere on climatological time scales (OZMAP) and equatorial dynamics: Seasonal variations of ozone trends</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Entzian, G.; Grasnick, K. H.; Taubenheim, J.</p> <p>1989-01-01</p> <p>The long term trends (least square linear regression with time) of ozone content at seven European, seven North American, three Japanese and two tropical stations during 21 years (1964 to 1984) are analyzed. In all regions negative trends are observed during the 1970s, but are partly compensated by limited periods of positive trends during the late 1960s and late 1970s. Solely the North American ozone data show negative trends in all 10 year periods. When the long term ozone trends are evaluated for each month of the year separately, a seasonal variation is revealed, which in Europe and North America has largest negative trends in late winter and spring. While in Europe the negative trends in winter/spring are partly compensated by positive trends in summer, in North America the summer values reach only zero, retaining the significant negative trend in annual mean values. In contrast to the antarctic ozone hole, the spring reduction of ozone in Europe and in North America is associated with stratospheric temperatures increasing in the analyzed period and therefore is consistent with the major natural ozone production and loss processes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27716414','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27716414"><span>Analyzing climate variations at multiple timescales can guide Zika virus response measures.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Muñoz, Ángel G; Thomson, Madeleine C; Goddard, Lisa; Aldighieri, Sylvain</p> <p>2016-10-06</p> <p>The emergence of Zika virus (ZIKV) in Latin America and the Caribbean in 2014-2016 occurred during a period of severe drought and unusually high temperatures, conditions that have been associated with the 2015-2016 El Niño event, and/or climate change; however, no quantitative assessment has been made to date. Analysis of related flaviviruses transmitted by the same vectors suggests that ZIKV dynamics are sensitive to climate seasonality and longer-term variability and trends. A better understanding of the climate conditions conducive to the 2014-2016 epidemic may permit the development of climate-informed short and long-term strategies for ZIKV prevention and control. Using a novel timescale-decomposition methodology, we demonstrate that the extreme climate anomalies observed in most parts of South America during the current epidemic are not caused exclusively by El Niño or climate change, but by a combination of climate signals acting at multiple timescales. In Brazil, the dry conditions present in 2013-2015 are primarily explained by year-to-year variability superimposed on decadal variability, but with little contribution of long-term trends. In contrast, the warm temperatures of 2014-2015 resulted from the compound effect of climate change, decadal and year-to-year climate variability. ZIKV response strategies made in Brazil during the drought concurrent with the 2015-2016 El Niño event, may require revision in light of the likely return of rainfall associated with the borderline La Niña event expected in 2016-2017. Temperatures are likely to remain warm given the importance of long term and decadal scale climate signals. The Author(s)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018SoPh..293...76W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018SoPh..293...76W"><span>Decoupling Solar Variability and Instrument Trends Using the Multiple Same-Irradiance-Level (MuSIL) Analysis Technique</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Woods, Thomas N.; Eparvier, Francis G.; Harder, Jerald; Snow, Martin</p> <p>2018-05-01</p> <p>The solar spectral irradiance (SSI) dataset is a key record for studying and understanding the energetics and radiation balance in Earth's environment. Understanding the long-term variations of the SSI over timescales of the 11-year solar activity cycle and longer is critical for many Sun-Earth research topics. Satellite measurements of the SSI have been made since the 1970s, most of them in the ultraviolet, but recently also in the visible and near-infrared. A limiting factor for the accuracy of previous solar variability results is the uncertainties for the instrument degradation corrections, which need fairly large corrections relative to the amount of solar cycle variability at some wavelengths. The primary objective of this investigation has been to separate out solar cycle variability and any residual uncorrected instrumental trends in the SSI measurements from the Solar Radiation and Climate Experiment (SORCE) mission and the Thermosphere, Mesosphere, Ionosphere, Energetic, and Dynamics (TIMED) mission. A new technique called the Multiple Same-Irradiance-Level (MuSIL) analysis has been developed, which examines an SSI time series at different levels of solar activity to provide long-term trends in an SSI record, and the most common result is a downward trend that most likely stems from uncorrected instrument degradation. This technique has been applied to each wavelength in the SSI records from SORCE (2003 - present) and TIMED (2002 - present) to provide new solar cycle variability results between 27 nm and 1600 nm with a resolution of about 1 nm at most wavelengths. This technique, which was validated with the highly accurate total solar irradiance (TSI) record, has an estimated relative uncertainty of about 5% of the measured solar cycle variability. The MuSIL results are further validated with the comparison of the new solar cycle variability results from different solar cycles.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998IJCli..18..583R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998IJCli..18..583R"><span>Identifying trends in climate: an application to the cenozoic</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Richards, Gordon R.</p> <p>1998-05-01</p> <p>The recent literature on trending in climate has raised several issues, whether trends should be modeled as deterministic or stochastic, whether trends are nonlinear, and the relative merits of statistical models versus models based on physics. This article models trending since the late Cretaceous. This 68 million-year interval is selected because the reliability of tests for trending is critically dependent on the length of time spanned by the data. Two main hypotheses are tested, that the trend has been caused primarily by CO2 forcing, and that it reflects a variety of forcing factors which can be approximated by statistical methods. The CO2 data is obtained from model simulations. Several widely-used statistical models are found to be inadequate. ARIMA methods parameterize too much of the short-term variation, and do not identify low frequency movements. Further, the unit root in the ARIMA process does not predict the long-term path of temperature. Spectral methods also have little ability to predict temperature at long horizons. Instead, the statistical trend is estimated using a nonlinear smoothing filter. Both of these paradigms make it possible to model climate as a cointegrated process, in which temperature can wander quite far from the trend path in the intermediate term, but converges back over longer horizons. Comparing the forecasting properties of the two trend models demonstrates that the optimal forecasting model includes CO2 forcing and a parametric representation of the nonlinear variability in climate.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70048257','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70048257"><span>Extreme events, trends, and variability in Northern Hemisphere lake-ice phenology (1855-2005)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Benson, Barbara J.; Magnuson, John J.; Jensen, Olaf P.; Card, Virginia M.; Hodgkins, Glenn; Korhonen, Johanna; Livingstone, David M.; Stewart, Kenton M.; Weyhenmeyer, Gesa A.; Granin, Nick G.</p> <p>2012-01-01</p> <p>Often extreme events, more than changes in mean conditions, have the greatest impact on the environment and human well-being. Here we examine changes in the occurrence of extremes in the timing of the annual formation and disappearance of lake ice in the Northern Hemisphere. Both changes in the mean condition and in variability around the mean condition can alter the probability of extreme events. Using long-term ice phenology data covering two periods 1855–6 to 2004–5 and 1905–6 to 2004–5 for a total of 75 lakes, we examined patterns in long-term trends and variability in the context of understanding the occurrence of extreme events. We also examined patterns in trends for a 30-year subset (1975–6 to 2004–5) of the 100-year data set. Trends for ice variables in the recent 30-year period were steeper than those in the 100- and 150-year periods, and trends in the 150-year period were steeper than in the 100-year period. Ranges of rates of change (days per decade) among time periods based on linear regression were 0.3−1.6 later for freeze, 0.5−1.9 earlier for breakup, and 0.7−4.3 shorter for duration. Mostly, standard deviation did not change, or it decreased in the 150-year and 100-year periods. During the recent 50-year period, standard deviation calculated in 10-year windows increased for all ice measures. For the 150-year and 100-year periods changes in the mean ice dates rather than changes in variability most strongly influenced the significant increases in the frequency of extreme lake ice events associated with warmer conditions and decreases in the frequency of extreme events associated with cooler conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.4193S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.4193S"><span>Trend analysis of Arctic sea ice extent</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Silva, M. E.; Barbosa, S. M.; Antunes, Luís; Rocha, Conceição</p> <p>2009-04-01</p> <p>The extent of Arctic sea ice is a fundamental parameter of Arctic climate variability. In the context of climate change, the area covered by ice in the Arctic is a particularly useful indicator of recent changes in the Arctic environment. Climate models are in near universal agreement that Arctic sea ice extent will decline through the 21st century as a consequence of global warming and many studies predict a ice free Arctic as soon as 2012. Time series of satellite passive microwave observations allow to assess the temporal changes in the extent of Arctic sea ice. Much of the analysis of the ice extent time series, as in most climate studies from observational data, have been focussed on the computation of deterministic linear trends by ordinary least squares. However, many different processes, including deterministic, unit root and long-range dependent processes can engender trend like features in a time series. Several parametric tests have been developed, mainly in econometrics, to discriminate between stationarity (no trend), deterministic trend and stochastic trends. Here, these tests are applied in the trend analysis of the sea ice extent time series available at National Snow and Ice Data Center. The parametric stationary tests, Augmented Dickey-Fuller (ADF), Phillips-Perron (PP) and the KPSS, do not support an overall deterministic trend in the time series of Arctic sea ice extent. Therefore, alternative parametrizations such as long-range dependence should be considered for characterising long-term Arctic sea ice variability.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2964215','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2964215"><span>Satellite-based global-ocean mass balance estimates of interannual variability and emerging trends in continental freshwater discharge</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Syed, Tajdarul H.; Famiglietti, James S.; Chambers, Don P.; Willis, Josh K.; Hilburn, Kyle</p> <p>2010-01-01</p> <p>Freshwater discharge from the continents is a key component of Earth’s water cycle that sustains human life and ecosystem health. Surprisingly, owing to a number of socioeconomic and political obstacles, a comprehensive global river discharge observing system does not yet exist. Here we use 13 years (1994–2006) of satellite precipitation, evaporation, and sea level data in an ocean mass balance to estimate freshwater discharge into the global ocean. Results indicate that global freshwater discharge averaged 36,055 km3/y for the study period while exhibiting significant interannual variability driven primarily by El Niño Southern Oscillation cycles. The method described here can ultimately be used to estimate long-term global discharge trends as the records of sea level rise and ocean temperature lengthen. For the relatively short 13-year period studied here, global discharge increased by 540 km3/y2, which was largely attributed to an increase of global-ocean evaporation (768 km3/y2). Sustained growth of these flux rates into long-term trends would provide evidence for increasing intensity of the hydrologic cycle. PMID:20921364</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H42D..02E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H42D..02E"><span>Sensitivity of intermittent streams to climate variations in the western United States</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eng, K.; Wolock, D.; Dettinger, M. D.</p> <p>2014-12-01</p> <p>There is a great deal of interest in streamflow changes caused by climate change because of the potential negative effects on aquatic biota and water supplies. Most previous studies have focused on perennial streams, and only a few studies have examined the effect of climate variability on intermittent streams. Our objective in this study was to evaluate the sensitivity of intermittent streams to historical variability in climate in the semi-arid regions of the western United States. This study was carried out at 45 intermittent streams that had a minimum of 45 years of daily-streamgage record by evaluating: (1) correlations among time series of flow metrics (number of zero-flow events, the average of the central 50% and largest 10% of flows) with climate, and (2) decadal changes in the seasonality and long-term trends of these flow metrics. Results showed strong associations between the low-flow metrics and historical changes in climate. The decadal analysis, in contrast, suggested no significant seasonal shifts or decade-to-decade trends in the low-flow metrics. The lack of trends or changes in seasonality is likely due to unchanged long-term patterns in precipitation over the time period examined.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PrOce.159...86K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PrOce.159...86K"><span>Multidecadal, centennial, and millennial variability in sardine and anchovy abundances in the western North Pacific and climate-fish linkages during the late Holocene</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kuwae, Michinobu; Yamamoto, Masanobu; Sagawa, Takuya; Ikehara, Ken; Irino, Tomohisa; Takemura, Keiji; Takeoka, Hidetaka; Sugimoto, Takashige</p> <p>2017-12-01</p> <p>Paleorecords of pelagic fish abundance could better define the nature of fishery productivity dynamics and help understand responses of pelagic fish stocks to long-term climate changes. We report a high-resolution record of sardine and anchovy scale deposition rates (SDRs) from Beppu Bay, Southwest Japan, showing multidecadal and centennial variability in the abundance of Japanese sardine and Japanese anchovy during the last 2850 years. Variations in the sardine SDR showed periodicities at ∼50, ∼100, and ∼300 yr, while variations in the anchovy SDR showed periodicities at ∼30 and ∼260 yr. Comparisons between and correlation analyses of the time series of the sardine and anchovy SDRs demonstrate that there is not a consistent out-of-phase relationship during the last 2850 years. This indicates that the multidecadal alternations in the sardine and anchovy populations commonly seen in the 20th century did not necessarily occur during earlier periods. The Japanese sardine SDR record shows a long-term decreasing trend in the amplitudes of the multidecadal to centennial fluctuations. This decreasing trend may have resulted from an increasing trend in the winter sea surface temperature in the western North Pacific. The multicentennial variability in sardine abundance during the last millennium is consistent with the variabilities in the abnormal snow index in East Asia and the American tree ring-based Pacific Decadal Oscillation index, suggesting a basin-wide or regional climate-marine ecosystem linkage.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ThApC.112..553A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ThApC.112..553A"><span>Non-parametric trend analysis of the aridity index for three large arid and semi-arid basins in Iran</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ahani, Hossien; Kherad, Mehrzad; Kousari, Mohammad Reza; van Roosmalen, Lieke; Aryanfar, Ramin; Hosseini, Seyyed Mashaallah</p> <p>2013-05-01</p> <p>Currently, an important scientific challenge that researchers are facing is to gain a better understanding of climate change at the regional scale, which can be especially challenging in an area with low and highly variable precipitation amounts such as Iran. Trend analysis of the medium-term change using ground station observations of meteorological variables can enhance our knowledge of the dominant processes in an area and contribute to the analysis of future climate projections. Generally, studies focus on the long-term variability of temperature and precipitation and to a lesser extent on other important parameters such as moisture indices. In this study the recent 50-year trends (1955-2005) of precipitation (P), potential evapotranspiration (PET), and aridity index (AI) in monthly time scale were studied over 14 synoptic stations in three large Iran basins using the Mann-Kendall non-parametric test. Additionally, an analysis of the monthly, seasonal and annual trend of each parameter was performed. Results showed no significant trends in the monthly time series. However, PET showed significant, mostly decreasing trends, for the seasonal values, which resulted in a significant negative trend in annual PET at five stations. Significant negative trends in seasonal P values were only found at a number of stations in spring and summer and no station showed significant negative trends in annual P. Due to the varied positive and negative trends in annual P and to a lesser extent PET, almost as many stations with negative as positive trends in annual AI were found, indicating that both drying and wetting trends occurred in Iran. Overall, the northern part of the study area showed an increasing trend in annual AI which meant that the region became wetter, while the south showed decreasing trends in AI.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.2865L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.2865L"><span>Solar cycle and long term variations of mesospheric ice layers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lübken, Franz-Josef; Berger, Uwe; Kiliani, Johannes; Baumgarten, Gerd; Fiedler, Jens; Gerding, Michael</p> <p>2010-05-01</p> <p>Ice layers in the summer mesosphere at middle and polar latitudes, frequently called `noctilucent clouds' (NLC) or `polar mesosphere clouds'(PMC), are considered to be sensitive indicators of long term changes in the middle atmosphere. We present a summary of long term observations from the ground and from satellites and compare with results from the LIMA model (Leibniz Institute Middle Atmosphere Model). LIMA nicely reproduces mean conditions of the summer mesopause region and also mean characteristics of ice layers. LIMA nudges to ECMWF data in the troposphere and lower stratosphere which influences the background conditions in the mesosphere and thereby the morphology of ice clouds. A strong correlation between temperatures and PMC altitudes is observed. Applied to historical measurements this give s negligible temperature trends at PMC altitudes (approximately 0.01-0.02 K/y). Trace gas concentrations are kept constant in LIMA except for water vapor which is modified by variable solar radiation. Still, long term trends in temperatures and ice layer parameters are observed, consistent with observations. As will be shown, these trends originate in the stratosphere. Solar cycle effects are expected in ice layers due to variations in background temperatures and water paper. We will present results from LIMA regarding solar cycle variations and compare with NLC observations at our lidar stations in Kühlungsborn (54°N) and ALOMAR (69°N), and also with satellite measurements.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70015321','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70015321"><span>Water-quality trends in the nation's rivers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Smith, R.A.; Alexander, R.B.; Wolman, M.G.</p> <p>1987-01-01</p> <p>Water-quality records from two nationwide sampling networks now permit nationally consistent analysis of long-term water-quality trends at more than 300 locations on major U.S. rivers. Observed trends in 24 measures of water quality for the period from 1974 to 1981 provide new insight into changes in stream quality that occurred during a time of major changes in both terrestrial and atmospheric influences on surface waters. Particularly noteworthy are widespread decreases in fecal bacteria and lead concentrations and widespread increases in nitrate, chloride, arsenic, and cadmium concentrations. Recorded increases in municipal waste treatment, use of salt on highways, and nitrogen fertilizer application, along with decreases in leaded gasoline consumption and regionally variable trends in coal production and combustion during the period appear to be reflected in water-quality changes.Water-quality records from two nationwide sampling networks now permit nationally consistent analysis of long-term water-quality trends at more than 300 locations on major U. S. rivers. Observed trends in 24 measures of water quality for the period from 1974 to 1981 provide new insight into changes in stream quality that occurred during a time of major changes in both terrestrial and atmospheric influences on surface waters. Particularly noteworthy are widespread decreases in fecal bacteria and lead concentrations and widespread increases in nitrate, chloride, arsenic, and cadmium concentrations. Recorded increases in municipal waste treatment, use of salt on highways, and nitrogen fertilizer application, along with decreases in leaded gasoline consumption and regionally variable trends in coal production and combustion during the period appear to be reflected in water-quality changes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A32G..03G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A32G..03G"><span>Santa Ana Winds of Southern California: Their Climatology and Variability Spanning 6.5 Decades from Regional Dynamical Modelling</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guzman-Morales, J.; Gershunov, A.</p> <p>2015-12-01</p> <p>Santa Ana Winds (SAWs) are an integral feature of the regional climate of Southern California/Northern Baja California region. In spite of their tremendous episodic impacts on the health, economy and mood of the region, climate-scale behavior of SAW is poorly understood. In the present work, we identify SAWs in mesoscale dynamical downscaling of a global reanalysis product and construct an hourly SAW catalogue spanning 65 years. We describe the long-term SAW climatology at relevant time-space resolutions, i.e, we developed local and regional SAW indices and analyse their variability on hourly, daily, annual, and multi-decadal timescales. Local and regional SAW indices are validated with available anemometer observations. Characteristic behaviors are revealed, e.g. the SAW intensity-duration relationship. At interdecadal time scales, we find that seasonal SAW activity is sensitive to prominent large-scale low-frequency modes of climate variability rooted in the tropical and north Pacific ocean-atmosphere system that are also known to affect the hydroclimate of this region. Lastly, we do not find any long-term trend in SAW frequency and intensity as previously reported. Instead, we identify a significant long-term trend in SAW behavior whereby contribution of extreme SAW events to total seasonal SAW activity has been increasing at the expense of moderate events. These findings motivate further investigation on SAW evolution in future climate and its impact on wildfires.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PApGe.tmp...30G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PApGe.tmp...30G"><span>Long-Term Trends, Variability and Extremes of In Situ Sea Surface Temperature Measured Along the Eastern Adriatic Coast and its Relationship to Hemispheric Processes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grbec, Branka; Matić, Frano; Beg Paklar, Gordana; Morović, Mira; Popović, Ružica; Vilibić, Ivica</p> <p>2018-02-01</p> <p>This paper examines long-term series of in situ sea surface temperature (SST) data measured at nine coastal and one open sea stations along the eastern Adriatic Sea for the period 1959-2015. Monthly and yearly averages were used to document SST trends and variability, while clustering and connections to hemispheric indices were achieved by applying the Principal Component Analysis (PCA) and Self-Organizing Maps (SOM) method. Both PCA and SOM revealed the dominance of temporal changes with respect to the effects of spatial differences in SST anomalies, indicating the prevalence of hemispheric processes over local dynamics, such as bora wind spatial inhomogeneity. SST extremes were connected with blocking atmospheric patterns. A substantial warming between 1979 and 2015, in total exceeding 1 °C, was preceded by a period with a negative SST trend, implying strong multidecadal variability in the Adriatic. The strongest connection was found between yearly SST and the East Atlantic (EA) pattern, while North Atlantic Oscillation (NAO) and East Atlantic/West Russia (EAWR) patterns were found to also affect February SST values. Quantification of the Adriatic SST and their connection to hemispheric indices allow for more precise projections of future SST, considered to be rather important for Adriatic thermohaline circulation, biogeochemistry and fisheries, and sensitive to ongoing climate change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70038501','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70038501"><span>The paradox of cooling streams in a warming world: Regional climate trends do not parallel variable local trends in stream temperature in the Pacific continental United States</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Arismendi, Ivan; Johnson, Sherri; Dunham, Jason B.; Haggerty, Roy; Hockman-Wert, David</p> <p>2012-01-01</p> <p>Temperature is a fundamentally important driver of ecosystem processes in streams. Recent warming of terrestrial climates around the globe has motivated concern about consequent increases in stream temperature. More specifically, observed trends of increasing air temperature and declining stream flow are widely believed to result in corresponding increases in stream temperature. Here, we examined the evidence for this using long-term stream temperature data from minimally and highly human-impacted sites located across the Pacific continental United States. Based on hypothesized climate impacts, we predicted that we should find warming trends in the maximum, mean and minimum temperatures, as well as increasing variability over time. These predictions were not fully realized. Warming trends were most prevalent in a small subset of locations with longer time series beginning in the 1950s. More recent series of observations (1987-2009) exhibited fewer warming trends and more cooling trends in both minimally and highly human-influenced systems. Trends in variability were much less evident, regardless of the length of time series. Based on these findings, we conclude that our perspective of climate impacts on stream temperatures is clouded considerably by a lack of long-termdata on minimally impacted streams, and biased spatio-temporal representation of existing time series. Overall our results highlight the need to develop more mechanistic, process-based understanding of linkages between climate change, other human impacts and stream temperature, and to deploy sensor networks that will provide better information on trends in stream temperatures in the future.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/10583952','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/10583952"><span>Global Warming and Northern Hemisphere Sea Ice Extent.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vinnikov; Robock; Stouffer; Walsh; Parkinson; Cavalieri; Mitchell; Garrett; Zakharov</p> <p>1999-12-03</p> <p>Surface and satellite-based observations show a decrease in Northern Hemisphere sea ice extent during the past 46 years. A comparison of these trends to control and transient integrations (forced by observed greenhouse gases and tropospheric sulfate aerosols) from the Geophysical Fluid Dynamics Laboratory and Hadley Centre climate models reveals that the observed decrease in Northern Hemisphere sea ice extent agrees with the transient simulations, and both trends are much larger than would be expected from natural climate variations. From long-term control runs of climate models, it was found that the probability of the observed trends resulting from natural climate variability, assuming that the models' natural variability is similar to that found in nature, is less than 2 percent for the 1978-98 sea ice trends and less than 0.1 percent for the 1953-98 sea ice trends. Both models used here project continued decreases in sea ice thickness and extent throughout the next century.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRD..11812257S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRD..11812257S"><span>Detection of carbon monoxide trends in the presence of interannual variability</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Strode, Sarah A.; Pawson, Steven</p> <p>2013-11-01</p> <p>in fossil fuel emissions are a major driver of changes in atmospheric CO, but detection of trends in CO from anthropogenic sources is complicated by the presence of large interannual variability (IAV) in biomass burning. We use a multiyear model simulation of CO with year-specific biomass burning to predict the number of years needed to detect the impact of changes in Asian anthropogenic emissions on downwind regions. Our study includes two cases for changing anthropogenic emissions: a stepwise change of 15% and a linear trend of 3% yr-1. We first examine how well the model reproduces the observed IAV of CO over the North Pacific, since this variability impacts the time needed to detect significant anthropogenic trends. The modeled IAV over the North Pacific correlates well with that seen from the Measurements of Pollution in the Troposphere (MOPITT) instrument but underestimates the magnitude of the variability. The model predicts that a 3% yr-1 trend in Asian anthropogenic emissions would lead to a statistically significant trend in CO surface concentration in the western United States within 12 years, and accounting for Siberian boreal biomass-burning emissions greatly reduces the number of years needed for trend detection. Combining the modeled trend with the observed MOPITT variability at 500 hPa, we estimate that the 3% yr-1 trend could be detectable in satellite observations over Asia in approximately a decade. Our predicted timescales for trend detection highlight the importance of long-term measurements of CO from satellites.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMGC32A..05G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMGC32A..05G"><span>Coping with climate variability and long-term climate trends for Nicaraguan maize-bean farmers (Invited)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gourdji, S.; Zelaya Martinez, C.; Martinez Valle, A.; Mejia, O.; Laderach, P.; Lobell, D. B.</p> <p>2013-12-01</p> <p>Climate variability and change impact farmers at different timescales, but both are of concern for livelihoods and long-term viability of small farms in tropical, rain-fed agricultural systems. This study uses a historical dataset to analyze the impact of 40-year climate trends in Nicaragua on bean production, a staple crop that is an important source of calories and protein in the local diet, particularly in rural areas and in lower income classes. Bean yields are sensitive to rising temperatures, but also frequently limited by seasonal drought and low soil fertility. We use an empirical model to relate department-level yields to spatial variation and inter-annual fluctuations in historical precipitation, temperature and extreme rain events. We then use this model to quantify the impact on yields of long-term observed warming in day and night temperatures, increases in rainfall intensity, longer gaps between rain events, a shorter rainy season and overall drying in certain regions of the country. Preliminary results confirm the negative impacts of warming night temperatures, higher vapor pressure deficits, and longer gaps between rain events on bean yields, although some drying at harvest time has helped to reduce rotting. Across all bean-growing areas, these climate trends have led to a ~10% yield decline per decade relative to a stationary climate and production system, with this decline reaching up to ~20% in the dry northern highlands. In regions that have been particularly impacted by these trends, we look for evidence of farm abandonment, increases in off-farm employment, or on-farm adaptation solutions through crop diversification, use of drought or heat-tolerant seed, and adoption of rainwater harvesting. We will also repeat the modeling exercise for maize, another staple crop providing ~25% of daily calories at the national scale, but which is projected to be more resilient to climate trends.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29339262','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29339262"><span>The long-term physical and psychological health impacts of flooding: A systematic mapping.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhong, Shuang; Yang, Lianping; Toloo, Sam; Wang, Zhe; Tong, Shilu; Sun, Xiaojie; Crompton, David; FitzGerald, Gerard; Huang, Cunrui</p> <p>2018-06-01</p> <p>Flooding has caused significant and wide ranging long-term health impacts for affected populations. However, until now, the long-term health outcomes, epidemiological trends and specific impact factors of flooding had not been identified. In this study, the relevant literature was systematically mapped to create the first synthesis of the evidence of the long-term health impacts of flooding. The systematic mapping method was used to collect and categorize all the relevant literature. A study was included if it had a description or measurement of health impacts over six months after flooding. The search was limited to peer reviewed articles and grey literature written in English, published from 1996 to 2016. A total of 56 critical articles were extracted for the final map, including 5 qualitative and 51 quantitative studies. Most long-term studies investigated the psychological impacts of flooding, including PTSD, depression, anxiety, psychiatric disorders, sleep disorder and suicide. Others investigated the physiological impacts, including health-related quality of life, acute myocardial infarction, chronic diseases, and malnutrition. Social support was proved to be protective factors that can improve health outcomes in the long-term after flooding. To date, there have been relatively few reviews had focused on the long-term health impacts of flooding. This study coded and catalogued the existing evidence across a wide range of variables and described the long-term health consequences within a conceptual map. Although there was no boundary between the short-term and the long-term impacts of flooding, the identified health outcomes in this systematic mapping could be used to define long-term health impacts. The studies showed that the prevalence of psychological diseases had a reversed increasing trend occurred even in the long-term in relatively poor post-flooding environments. Further cohort or longitudinal research focused on disability, chronic diseases, relocation population, and social interventions after flooding, are urgently required. Copyright © 2018 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DSRII.143....1W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DSRII.143....1W"><span>Long-term trend of satellite-observed significant wave height and impact on ecosystem in the East/Japan Sea</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Woo, Hye-Jin; Park, Kyung-Ae</p> <p>2017-09-01</p> <p>Significant wave height (SWH) data of nine satellite altimeters were validated with in-situ SWH measurements from buoy stations in the East/Japan Sea (EJS) and the Northwest Pacific Ocean. The spatial and temporal variability of extreme SWHs was investigated by defining the 90th, 95th, and 99th percentiles based on percentile analysis. The annual mean of extreme SWHs was dramatically increased by 3.45 m in the EJS, which is significantly higher than the normal mean of about 1.44 m. The spatial distributions of SWHs showed significantly higher values in the eastern region of the EJS than those in the western part. Characteristic seasonality was found from the time-series SWHs with high SWHs (>2.5 m) in winter but low values (<1 m) in summer. The trends of the normal and extreme (99th percentile) SWHs in the EJS had a positive value of 0.0056 m year-1 and 0.0125 m year-1, respectively. The long-term trend demonstrated that higher SWH values were more extreme with time during the past decades. The predominant spatial distinctions between the coastal regions in the marginal seas of the Northwest Pacific Ocean and open ocean regions were presented. In spring, both normal and extreme SWHs showed substantially increasing trends in the EJS. Finally, we first presented the impact of the long-term trend of extreme SWHs on the marine ecosystem through vertical mixing enhancement in the upper ocean of the EJS.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013OcDyn..63..961M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013OcDyn..63..961M"><span>Wave climate simulation for southern region of the South China Sea</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mirzaei, Ali; Tangang, Fredolin; Juneng, Liew; Mustapha, Muzneena Ahmad; Husain, Mohd Lokman; Akhir, Mohd Fadzil</p> <p>2013-08-01</p> <p>This study investigates long-term variability and wave characteristic trends in the southern region of the South China Sea (SCS). We implemented the state-of-the art WAVEWATCH III spectral wave model to simulate a 31-year wave hindcast. The simulation results were used to assess the inter-annual variability and long-term changes in the SCS wave climate for the period 1979 to 2009. The model was forced with Climate Forecast System Reanalysis winds and validated against altimeter data and limited available measurements from an Acoustic Wave and Current recorder located offshore of Terengganu, Malaysia. The mean annual significant wave height and peak wave period indicate the occurrence of higher wave heights and wave periods in the central SCS and lower in the Sunda shelf region. Consistent with wind patterns, the wave direction also shows southeasterly (northwesterly) waves during the summer (winter) monsoon. This detailed hindcast demonstrates strong inter-annual variability of wave heights, especially during the winter months in the SCS. Significant wave height correlated negatively with Niño3.4 index during winter, spring and autumn seasons but became positive in the summer monsoon. Such correlations correspond well with surface wind anomalies over the SCS during El Nino events. During El Niño Modoki, the summer time positive correlation extends northeastwards to cover the entire domain. Although significant positive trends were found at 95 % confidence levels during May, July and September, there is significant negative trend in December covering the Sunda shelf region. However, the trend appears to be largely influenced by large El Niño signals.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4079564','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4079564"><span>Twenty Years of High-Resolution Sea Surface Temperature Imagery around Australia: Inter-Annual and Annual Variability</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Foster, Scott D.; Griffin, David A.; Dunstan, Piers K.</p> <p>2014-01-01</p> <p>The physical climate defines a significant portion of the habitats in which biological communities and species reside. It is important to quantify these environmental conditions, and how they have changed, as this will inform future efforts to study many natural systems. In this article, we present the results of a statistical summary of the variability in sea surface temperature (SST) time-series data for the waters surrounding Australia, from 1993 to 2013. We partition variation in the SST series into annual trends, inter-annual trends, and a number of components of random variation. We utilise satellite data and validate the statistical summary from these data to summaries of data from long-term monitoring stations and from the global drifter program. The spatially dense results, available as maps from the Australian Oceanographic Data Network's data portal (http://www.cmar.csiro.au/geonetwork/srv/en/metadata.show?id=51805), show clear trends that associate with oceanographic features. Noteworthy oceanographic features include: average warming was greatest off southern West Australia and off eastern Tasmania, where the warming was around 0.6°C per decade for a twenty year study period, and insubstantial warming in areas dominated by the East Australian Current, but this area did exhibit high levels of inter-annual variability (long-term trend increases and decreases but does not increase on average). The results of the analyses can be directly incorporated into (biogeographic) models that explain variation in biological data where both biological and environmental data are on a fine scale. PMID:24988444</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70173452','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70173452"><span>Long-term citizen-collected data reveal geographical patterns and temporal trends in lake water clarity</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lottig, Noah R.; Wagner, Tyler; Henry, Emily N.; Cheruvelil, Kendra Spence; Webster, Katherine E.; Downing, John A.; Stow, Craig A.</p> <p>2014-01-01</p> <p>We compiled a lake-water clarity database using publically available, citizen volunteer observations made between 1938 and 2012 across eight states in the Upper Midwest, USA. Our objectives were to determine (1) whether temporal trends in lake-water clarity existed across this large geographic area and (2) whether trends were related to the lake-specific characteristics of latitude, lake size, or time period the lake was monitored. Our database consisted of >140,000 individual Secchi observations from 3,251 lakes that we summarized per lake-year, resulting in 21,020 summer averages. Using Bayesian hierarchical modeling, we found approximately a 1% per year increase in water clarity (quantified as Secchi depth) for the entire population of lakes. On an individual lake basis, 7% of lakes showed increased water clarity and 4% showed decreased clarity. Trend direction and strength were related to latitude and median sample date. Lakes in the southern part of our study-region had lower average annual summer water clarity, more negative long-term trends, and greater inter-annual variability in water clarity compared to northern lakes. Increasing trends were strongest for lakes with median sample dates earlier in the period of record (1938–2012). Our ability to identify specific mechanisms for these trends is currently hampered by the lack of a large, multi-thematic database of variables that drive water clarity (e.g., climate, land use/cover). Our results demonstrate, however, that citizen science can provide the critical monitoring data needed to address environmental questions at large spatial and long temporal scales. Collaborations among citizens, research scientists, and government agencies may be important for developing the data sources and analytical tools necessary to move toward an understanding of the factors influencing macro-scale patterns such as those shown here for lake water clarity.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4005745','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4005745"><span>Long-Term Citizen-Collected Data Reveal Geographical Patterns and Temporal Trends in Lake Water Clarity</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lottig, Noah R.; Wagner, Tyler; Norton Henry, Emily; Spence Cheruvelil, Kendra; Webster, Katherine E.; Downing, John A.; Stow, Craig A.</p> <p>2014-01-01</p> <p>We compiled a lake-water clarity database using publically available, citizen volunteer observations made between 1938 and 2012 across eight states in the Upper Midwest, USA. Our objectives were to determine (1) whether temporal trends in lake-water clarity existed across this large geographic area and (2) whether trends were related to the lake-specific characteristics of latitude, lake size, or time period the lake was monitored. Our database consisted of >140,000 individual Secchi observations from 3,251 lakes that we summarized per lake-year, resulting in 21,020 summer averages. Using Bayesian hierarchical modeling, we found approximately a 1% per year increase in water clarity (quantified as Secchi depth) for the entire population of lakes. On an individual lake basis, 7% of lakes showed increased water clarity and 4% showed decreased clarity. Trend direction and strength were related to latitude and median sample date. Lakes in the southern part of our study-region had lower average annual summer water clarity, more negative long-term trends, and greater inter-annual variability in water clarity compared to northern lakes. Increasing trends were strongest for lakes with median sample dates earlier in the period of record (1938–2012). Our ability to identify specific mechanisms for these trends is currently hampered by the lack of a large, multi-thematic database of variables that drive water clarity (e.g., climate, land use/cover). Our results demonstrate, however, that citizen science can provide the critical monitoring data needed to address environmental questions at large spatial and long temporal scales. Collaborations among citizens, research scientists, and government agencies may be important for developing the data sources and analytical tools necessary to move toward an understanding of the factors influencing macro-scale patterns such as those shown here for lake water clarity. PMID:24788722</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JHyd..555..708D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JHyd..555..708D"><span>Historical trends and high-resolution future climate projections in northern Tuscany (Italy)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>D'Oria, Marco; Ferraresi, Massimo; Tanda, Maria Giovanna</p> <p>2017-12-01</p> <p>This paper analyzes the historical precipitation and temperature trends and the future climate projections with reference to the northern part of Tuscany (Italy). The trends are identified and quantified at monthly and annual scale at gauging stations with data collected for long periods (60-90 years). An ensemble of 13 Regional Climate Models (RCMs), based on two Representative Concentration Pathways (RCP4.5 and RCP8.5), was then used to assess local scale future precipitation and temperature projections and to represent the uncertainty in the results. The historical data highlight a general decrease of the annual rainfall at a mean rate of 22 mm per decade but, in many cases, the tendencies are not statistically significant. Conversely, the annual mean temperature exhibits an upward trend, statistically significant in the majority of cases, with a warming rate of about 0.1 °C per decade. With reference to the model projections and the annual precipitation, the results are not concordant; the deviations between models in the same period are higher than the future changes at medium- (2031-2040) and long-term (2051-2060) and highlight that the model uncertainty and variability is high. According to the climate model projections, the warming of the study area is unequivocal; a mean positive increment of 0.8 °C at medium-term and 1.1 °C at long-term is expected with respect to the reference period (2003-2012) and the scenario RCP4.5; the increments grow to 0.9 °C and 1.9 °C for the RCP8.5. Finally, in order to check the observed climate change signals, the climate model projections were compared with the trends based on the historical data. A satisfactory agreement is obtained with reference to the precipitation; a systematic underestimation of the trend values with respect to the models, at medium- and long-term, is observed for the temperature data.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005GeoRL..32.6805P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005GeoRL..32.6805P"><span>Comparison and covalidation of ozone anomalies and variability observed in SBUV(/2) and Umkehr northern midlatitude ozone profile estimates</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Petropavlovskikh, I.; Ahn, Changwoo; Bhartia, P. K.; Flynn, L. E.</p> <p>2005-03-01</p> <p>This analysis presents comparisons of upper-stratosphere ozone information observed by two independent systems: the Solar Backscatter UltraViolet (SBUV and SBUV/2) satellite instruments, and ground-based Dobson spectrophotometers. Both the new SBUV Version 8 and the new UMK04 profile retrieval algorithms are optimized for studying long-term variability and trends in ozone. Trend analyses of the ozone time series from the SBUV(/2) data set are complex because of the multiple instruments involved, changes in the instruments' geo-location, and short periods of overlaps for inter-calibrations among different instruments. Three northern middle latitudes Dobson ground stations (Arosa, Boulder, and Tateno) are used in this analysis to validate the trend quality of the combined 25-year SBUV/2 time series, 1979 to 2003. Generally, differences between the satellite and ground-based data do not suggest any significant time-dependent shifts or trends. The shared features confirm the value of these data sets for studies of ozone variability.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26742651','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26742651"><span>Observing climate change trends in ocean biogeochemistry: when and where.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Henson, Stephanie A; Beaulieu, Claudie; Lampitt, Richard</p> <p>2016-04-01</p> <p>Understanding the influence of anthropogenic forcing on the marine biosphere is a high priority. Climate change-driven trends need to be accurately assessed and detected in a timely manner. As part of the effort towards detection of long-term trends, a network of ocean observatories and time series stations provide high quality data for a number of key parameters, such as pH, oxygen concentration or primary production (PP). Here, we use an ensemble of global coupled climate models to assess the temporal and spatial scales over which observations of eight biogeochemically relevant variables must be made to robustly detect a long-term trend. We find that, as a global average, continuous time series are required for between 14 (pH) and 32 (PP) years to distinguish a climate change trend from natural variability. Regional differences are extensive, with low latitudes and the Arctic generally needing shorter time series (<~30 years) to detect trends than other areas. In addition, we quantify the 'footprint' of existing and planned time series stations, that is the area over which a station is representative of a broader region. Footprints are generally largest for pH and sea surface temperature, but nevertheless the existing network of observatories only represents 9-15% of the global ocean surface. Our results present a quantitative framework for assessing the adequacy of current and future ocean observing networks for detection and monitoring of climate change-driven responses in the marine ecosystem. © 2016 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.9867M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.9867M"><span>Long and Short Term Variability of the Main Physical Parameters in the Coastal Area of the SE Baltic Proper</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mingelaite, Toma; Rukseniene, Viktorija; Dailidiene, Inga</p> <p>2015-04-01</p> <p>Keywords: SE Baltic Sea, coastal upwelling, IR Remote Sensing The memory of the ocean and seas of atmospheric forcing events contributes to the long-term climate change. Intensifying climate change processes in the North Atlantic region including Baltic Sea has drawn widespread interest, as a changing water temperature has ecological, economic and social impact in coastal areas of the Europe seas. In this work we analyse long and short term variability of the main physical parameters in the coastal area of the South Eastern Baltic Sea Proper. The analysis of long term variability is based on monitoring data measured in the South Eastern Baltic Sea for the last 50 years. The main focus of the long term variability is changes of hydro meteorological parameters relevant to the observed changes in the climate.The water salinity variations in the Baltic Sea near the Lithuanian coast and in the Curonian Lagoon, a shallow and enclosed sub-basin of the Baltic Sea, were analysed along with the time series of some related hydroclimatic factors. The short term water temperature and salinity variations were analysed with a strong focus on coastal upwelling events. Combining both remote sensing and in situ monitoring data physical parameters such as vertical salinity variations during upwelling events was analysed. The coastal upwelling in the SE Baltic Sea coast, depending on its scale and intensity, may lead to an intrusion of colder and saltier marine waters to the Curonian Lagoon resulting in hydrodynamic changes and pronounced temperature drop extending for 30-40 km further down the Lagoon. The study results show that increasing trends of water level, air and water temperature, and decreasing ice cover duration are related to the changes in meso-scale atmospheric circulation, and more specifically, to the changes in regional and local wind regime climate. That is in a good agreement with the increasing trends in local higher intensity of westerly winds, and with the winter NAO index that indicates the change and variations of the atmospheric circulation in the North Atlantic region, including the Baltic Sea area. This work is supported by "Lithuanian Maritime Sectors' Technologies and Environmental Research Development" project Nr. VP1-3.1-ŠMM-08-K-01-019 funded by the European Social Fund Agency.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.B31F2050M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.B31F2050M"><span>Multi-Scale Analysis of Trends in Northeastern Temperate Forest Springtime Phenology</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moon, M.; Melaas, E. K.; Sulla-menashe, D. J.; Friedl, M. A.</p> <p>2017-12-01</p> <p>The timing of spring leaf emergence is highly variable in many ecosystems, exerts first-order control growing season length, and significantly modulates seasonally-integrated photosynthesis. Numerous studies have reported trends toward earlier spring phenology in temperate forests, with some papers indicating that this trend is also leading to increased carbon uptake. At broad spatial scales, however, most of these studies have used data from coarse spatial resolution instruments such as MODIS, which does not resolve ecologically important landscape-scale patterns in phenology. In this work, we examine how long-term trends in spring phenology differ across three data sources acquired at different scales of measurements at the Harvard Forest in central Massachusetts. Specifically, we compared trends in the timing of phenology based on long-term in-situ measurements of phenology, estimates based on eddy-covariance measurements of net carbon uptake transition dates, and from two sources of satellite-based remote sensing (MODIS and Landsat) land surface phenology (LSP) data. Our analysis focused on the flux footprint surrounding the Harvard Forest Environmental Measurements (EMS) tower. Our results reveal clearly defined trends toward earlier springtime phenology in Landsat LSP and in the timing of tower-based net carbon uptake. However, we find no statistically significant trend in springtime phenology measured from MODIS LSP data products, possibly because the time series of MODIS observations is relatively short (13 years). The trend in tower-based transition data exhibited a larger negative value than the trend derived from Landsat LSP data (-0.42 and -0.28 days per year for 21 and 28 years, respectively). More importantly, these results have two key implications regarding how changes in spring phenology are impacting carbon uptake at landscape-scale. First, long-term trends in spring phenology can be quite different, depending on what data source is used to estimate the trend, and 2) the response of carbon uptake to climate change may be more sensitive than the response of land surface phenology itself.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2015/5131/sir20155131.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2015/5131/sir20155131.pdf"><span>Aquifer geometry, lithology, and water levels in the Anza–Terwilliger area—2013, Riverside and San Diego Counties, California</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Landon, Matthew K.; Morita, Andrew Y.; Nawikas, Joseph M.; Christensen, Allen H.; Faunt, Claudia C.; Langenheim, Victoria E.</p> <p>2015-11-24</p> <p>On the basis of data from 33 wells, water levels mostly declined between the fall of 2006 and the fall of 2013; the median decline was 5.1 feet during this period, for a median rate of decline of about 0.7 feet/year. Based on data from 40 wells, water-level changes between fall 2004 and fall 2013 were variable in magnitude and trend, but had a median decline of 2.4 feet and a median rate of decline of about 0.3 feet/ year. These differences in apparent rates of groundwater-level change highlight the value of ongoing water-level measurements to distinguish decadal, or longer term, trends in groundwater storage often associated with climatic variability and trends. Fifty-four long-term hydrographs indicated the sensitivity of groundwater levels to climatic conditions; they also showed a general decline in water levels across the study area since 1986 and, in some cases, dating back to the 1950s.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/1054032-testing-possible-influence-unknown-climate-forcings-upon-global-temperature-increases-from','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1054032-testing-possible-influence-unknown-climate-forcings-upon-global-temperature-increases-from"><span>Testing for the Possible Influence of Unknown Climate Forcings upon Global Temperature Increases from 1950-2000</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Anderson, Bruce T.; Knight, Jeff R.; Ringer, Mark A.</p> <p>2012-10-15</p> <p>Global-scale variations in the climate system over the last half of the twentieth century, including long-term increases in global-mean near-surface temperatures, are consistent with concurrent human-induced emissions of radiatively active gases and aerosols. However, such consistency does not preclude the possible influence of other forcing agents, including internal modes of climate variability or unaccounted for aerosol effects. To test whether other unknown forcing agents may have contributed to multidecadal increases in global-mean near-surface temperatures from 1950 to 2000, data pertaining to observed changes in global-scale sea surface temperatures and observed changes in radiatively active atmospheric constituents are incorporated into numericalmore » global climate models. Results indicate that the radiative forcing needed to produce the observed long-term trends in sea surface temperatures—and global-mean near-surface temperatures—is provided predominantly by known changes in greenhouse gases and aerosols. Further, results indicate that less than 10% of the long-term historical increase in global-mean near-surface temperatures over the last half of the twentieth century could have been the result of internal climate variability. In addition, they indicate that less than 25%of the total radiative forcing needed to produce the observed long-term trend in global-mean near-surface temperatures could have been provided by changes in net radiative forcing from unknown sources (either positive or negative). These results, which are derived from simple energy balance requirements, emphasize the important role humans have played in modifying the global climate over the last half of the twentieth century.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28545590','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28545590"><span>Effect of climatic variability on malaria trends in Baringo County, Kenya.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kipruto, Edwin K; Ochieng, Alfred O; Anyona, Douglas N; Mbalanya, Macrae; Mutua, Edna N; Onguru, Daniel; Nyamongo, Isaac K; Estambale, Benson B A</p> <p>2017-05-25</p> <p>Malaria transmission in arid and semi-arid regions of Kenya such as Baringo County, is seasonal and often influenced by climatic factors. Unravelling the relationship between climate variables and malaria transmission dynamics is therefore instrumental in developing effective malaria control strategies. The main aim of this study was to describe the effects of variability of rainfall, maximum temperature and vegetation indices on seasonal trends of malaria in selected health facilities within Baringo County, Kenya. Climate variables sourced from the International Research Institute (IRI)/Lamont-Doherty Earth Observatory (LDEO) climate database and malaria cases reported in 10 health facilities spread across four ecological zones (riverine, lowland, mid-altitude and highland) between 2004 and 2014 were subjected to a time series analysis. A negative binomial regression model with lagged climate variables was used to model long-term monthly malaria cases. The seasonal Mann-Kendall trend test was then used to detect overall monotonic trends in malaria cases. Malaria cases increased significantly in the highland and midland zones over the study period. Changes in malaria prevalence corresponded to variations in rainfall and maximum temperature. Rainfall at a time lag of 2 months resulted in an increase in malaria transmission across the four zones while an increase in temperature at time lags of 0 and 1 month resulted in an increase in malaria cases in the riverine and highland zones, respectively. Given the existence of a time lag between climatic variables more so rainfall and peak malaria transmission, appropriate control measures can be initiated at the onset of short and after long rains seasons.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JESS..126..113G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JESS..126..113G"><span>Trend analysis of evapotranspiration over India: Observed from long-term satellite measurements</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goroshi, Sheshakumar; Pradhan, Rohit; Singh, Raghavendra P.; Singh, K. K.; Parihar, Jai Singh</p> <p>2017-12-01</p> <p>Owing to the lack of consistent spatial time series data on actual evapotranspiration ( ET), very few studies have been conducted on the long-term trend and variability in ET at a national scale over the Indian subcontinent. The present study uses biome specific ET data derived from NOAA satellite's advanced very high resolution radiometer to investigate the trends and variability in ET over India from 1983 to 2006. Trend analysis using the non-parametric Mann-Kendall test showed that the domain average ET decreased during the period at a rate of 0.22 mm year^{-1}. A strong decreasing trend (m = -1.75 mm year^{-1}, F = 17.41, P 0.01) was observed in forest regions. Seasonal analyses indicated a decreasing trend during southwest summer monsoon (m= -0.320 mm season^{-1} year^{-1}) and post-monsoon period (m= -0.188 mm season^{-1 } year^{-1}). In contrast, an increasing trend was observed during northeast winter monsoon (m = 0.156 mm season^{-1 } year^{-1}) and pre-monsoon (m = 0.068 mm season^{-1 } year^{-1}) periods. Despite an overall net decline in the country, a considerable increase ( 4 mm year^{-1}) was observed over arid and semi-arid regions. Grid level correlation with various climatic parameters exhibited a strong positive correlation (r >0.5) of ET with soil moisture and precipitation over semi-arid and arid regions, whereas a negative correlation (r -0.5) occurred with temperature and insolation in dry regions of western India. The results of this analysis are useful for understanding regional ET dynamics and its relationship with various climatic parameters over India. Future studies on the effects of ET changes on the hydrological cycle, carbon cycle, and energy partitioning are needed to account for the feedbacks to the climate.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AAS...21934816T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AAS...21934816T"><span>Low-Frequency Temporal Variability in Mira and Semiregular Variables</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Templeton, Matthew R.; Karovska, M.; Waagen, E. O.</p> <p>2012-01-01</p> <p>We investigate low-frequency variability in a large sample of Mira and semiregular variables with long-term visual light curves from the AAVSO International Database. Our aim is to determine whether we can detect and measure long-timescale variable phenomena in these stars, for example photometric variations that might be associated with supergranular convection. We analyzed the long-term light curves of 522 variable stars of the Mira and SRa, b, c, and d classes. We calculated their low-frequency time-series spectra to characterize rednoise with the power density spectrum index, and then correlate this index with other observable characteristics such as spectral type and primary pulsation period. In our initial analysis of the sample, we see that the semiregular variables have a much broader range of spectral index than the Mira types, with the SRb subtype having the broadest range. Among Mira variables we see that the M- and S-type Miras have similarly wide ranges of index, while the C-types have the narrowest with generally shallower slopes. There is also a trend of steeper slope with larger amplitude, but at a given amplitude, a wide range of slopes are seen. The ultimate goal of the project is to identify stars with strong intrinsic red noise components as possible targets for resolved surface imaging with interferometry.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A51O..05A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A51O..05A"><span>The Interplay of Internal and Forced Modes of Hadley Cell Expansion: Lessons from the Global Warming Hiatus</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Amaya, D. J.; Siler, N.; Xie, S. P.; Miller, A. J.</p> <p>2017-12-01</p> <p>The poleward branches of the Hadley Cells show a robust shift poleward shift during the satellite era, leading to concerns over the possible encroachment of the globe's subtropical dry zones into currently temperate climates. The extent to which this trend is caused by anthropogenic forcing versus internal variability remains the subject of considerable debate. In this study, we us a joint EOF method to identify two distinct modes of Hadley Cell variability: (i) an anthropogenically-forced mode, which we identify using a 20-member simulation of the historical climate, and (ii) an internal mode, which identify using a 1000-year pre-industrial control simulation with a global climate model. The forced mode is found to be closely related to the TOA radiative imbalance and exhibits a long-term trend since 1860, while the internal mode is found to be essentially indistinguishable from the El Niño Southern Oscillation (ENSO). Together these two modes explain an average of 70% of the interannual variability seen in model "edge indices" over the historical period. Since 1980, the superposition of forced and internal modes has resulted in a period of accelerated Hadley Cell expansion and decelerated global warming (i.e., the "hiatus"). A comparison of the change in these modes since 1980 indicates that by 2013 the signal has emerged above the noise of internal variability in the Southern Hemisphere (SH), but not in the Northern Hemisphere (NH), with the latter also exhibiting strong zonal asymmetry, particularly in the North Atlantic. Our results highlight the important interplay of internal and forced modes of Hadley Cell width change and improve our understanding of the interannual variability and long-term trend seen in observations.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy..tmp..782A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy..tmp..782A"><span>The interplay of internal and forced modes of Hadley Cell expansion: lessons from the global warming hiatus</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Amaya, Dillon J.; Siler, Nicholas; Xie, Shang-Ping; Miller, Arthur J.</p> <p>2017-09-01</p> <p>The poleward branches of the Hadley Cells and the edge of the tropics show a robust poleward shift during the satellite era, leading to concerns over the possible encroachment of the globe's subtropical dry zones into currently temperate climates. The extent to which this trend is caused by anthropogenic forcing versus internal variability remains the subject of considerable debate. In this study, we use a Joint EOF method to identify two distinct modes of tropical width variability: (1) an anthropogenically-forced mode, which we identify using a 20-member simulation of the historical climate, and (2) an internal mode, which we identify using a 1000-year pre-industrial control simulation. The forced mode is found to be closely related to the top of the atmosphere radiative imbalance and exhibits a long-term trend since 1860, while the internal mode is essentially indistinguishable from the El Niño Southern Oscillation. Together these two modes explain an average of 70% of the interannual variability seen in model "edge indices" over the historical period. Since 1980, the superposition of forced and internal modes has resulted in a period of accelerated Hadley Cell expansion and decelerated global warming (i.e., the "hiatus"). A comparison of the change in these modes since 1980 indicates that by 2013 the signal has emerged above the noise of internal variability in the Southern Hemisphere, but not in the Northern Hemisphere, with the latter also exhibiting strong zonal asymmetry, particularly in the North Atlantic. Our results highlight the important interplay of internal and forced modes of tropical width change and improve our understanding of the interannual variability and long-term trend seen in observations.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2013/1222/pdf/ofr2013-1222.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2013/1222/pdf/ofr2013-1222.pdf"><span>Design tradeoffs for trend assessment in aquatic biological monitoring programs</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Gurtz, Martin E.; Van Sickle, John; Carlisle, Daren M.; Paulsen, Steven G.</p> <p>2013-01-01</p> <p>Assessments of long-term (multiyear) temporal trends in biological monitoring programs are generally undertaken without an adequate understanding of the temporal variability of biological communities. When the sources and levels of variability are unknown, managers cannot make informed choices in sampling design to achieve monitoring goals in a cost-effective manner. We evaluated different trend sampling designs by estimating components of both short- and long-term variability in biological indicators of water quality in streams. Invertebrate samples were collected from 32 sites—9 urban, 6 agricultural, and 17 relatively undisturbed (reference) streams—distributed throughout the United States. Between 5 and 12 yearly samples were collected at each site during the period 1993–2008, plus 2 samples within a 10-week index period during either 2007 or 2008. These data allowed calculation of four sources of variance for invertebrate indicators: among sites, among years within sites, interaction among sites and years (site-specific annual variation), and among samples collected within an index period at a site (residual). When estimates of these variance components are known, changes to sampling design can be made to improve trend detection. Design modifications that result in the ability to detect the smallest trend with the fewest samples are, from most to least effective: (1) increasing the number of years in the sampling period (duration of the monitoring program), (2) decreasing the interval between samples, and (3) increasing the number of repeat-visit samples per year (within an index period). This order of improvement in trend detection, which achieves the greatest gain for the fewest samples, is the same whether trends are assessed at an individual site or an average trend of multiple sites. In multiple-site surveys, increasing the number of sites has an effect similar to that of decreasing the sampling interval; the benefit of adding sites is greater when a new set of different sites is selected for each sampling effort than when the same sites are sampled each time. Understanding variance components of the ecological attributes of interest can lead to more cost-effective monitoring designs to detect trends.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70156005','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70156005"><span>Sensitivity of intermittent streams to climate variations in the USA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Eng, Kenny; Wolock, David M.; Dettinger, Mike</p> <p>2015-01-01</p> <p>There is a great deal of interest in the literature on streamflow changes caused by climate change because of the potential negative effects on aquatic biota and water supplies. Most previous studies have primarily focused on perennial streams, and there have been only a few studies examining the effect of climate variability on intermittent streams. Our objectives in this study were to (1) identify regions of similar zero-flow behavior, and (2) evaluate the sensitivity of intermittent streams to historical variability in climate in the United States. This study was carried out at 265 intermittent streams by evaluating: (1) correlations among time series of flow metrics (number of zero-flow events, the average of the central 50% and largest 10% of flows) with climate (magnitudes, durations and intensity), and (2) decadal changes in the seasonality and long-term trends of these flow metrics. Results identified five distinct seasonality patterns in the zero-flow events. In addition, strong associations between the low-flow metrics and historical changes in climate were found. The decadal analysis suggested no significant seasonal shifts or decade-to-decade trends in the low-flow metrics. The lack of trends or changes in seasonality is likely due to unchanged long-term patterns in precipitation over the time period examined.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28378830','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28378830"><span>Possible connections of the opposite trends in Arctic and Antarctic sea-ice cover.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yu, Lejiang; Zhong, Shiyuan; Winkler, Julie A; Zhou, Mingyu; Lenschow, Donald H; Li, Bingrui; Wang, Xianqiao; Yang, Qinghua</p> <p>2017-04-05</p> <p>Sea ice is an important component of the global climate system and a key indicator of climate change. A decreasing trend in Arctic sea-ice concentration is evident in recent years, whereas Antarctic sea-ice concentration exhibits a generally increasing trend. Various studies have investigated the underlying causes of the observed trends for each region, but possible linkages between the regional trends have not been studied. Here, we hypothesize that the opposite trends in Arctic and Antarctic sea-ice concentration may be linked, at least partially, through interdecadal variability of the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). Although evaluation of this hypothesis is constrained by the limitations of the sea-ice cover record, preliminary statistical analyses of one short-term and two long-term time series of observed and reanalysis sea-ice concentrations data suggest the possibility of the hypothesized linkages. For all three data sets, the leading mode of variability of global sea-ice concentration is positively correlated with the AMO and negatively correlated with the PDO. Two wave trains related to the PDO and the AMO appear to produce anomalous surface-air temperature and low-level wind fields in the two polar regions that contribute to the opposite changes in sea-ice concentration.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5381096','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5381096"><span>Possible connections of the opposite trends in Arctic and Antarctic sea-ice cover</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yu, Lejiang; Zhong, Shiyuan; Winkler, Julie A.; Zhou, Mingyu; Lenschow, Donald H.; Li, Bingrui; Wang, Xianqiao; Yang, Qinghua</p> <p>2017-01-01</p> <p>Sea ice is an important component of the global climate system and a key indicator of climate change. A decreasing trend in Arctic sea-ice concentration is evident in recent years, whereas Antarctic sea-ice concentration exhibits a generally increasing trend. Various studies have investigated the underlying causes of the observed trends for each region, but possible linkages between the regional trends have not been studied. Here, we hypothesize that the opposite trends in Arctic and Antarctic sea-ice concentration may be linked, at least partially, through interdecadal variability of the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). Although evaluation of this hypothesis is constrained by the limitations of the sea-ice cover record, preliminary statistical analyses of one short-term and two long-term time series of observed and reanalysis sea-ice concentrations data suggest the possibility of the hypothesized linkages. For all three data sets, the leading mode of variability of global sea-ice concentration is positively correlated with the AMO and negatively correlated with the PDO. Two wave trains related to the PDO and the AMO appear to produce anomalous surface-air temperature and low-level wind fields in the two polar regions that contribute to the opposite changes in sea-ice concentration. PMID:28378830</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29624669','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29624669"><span>Effects of hurricanes and climate oscillations on annual variation in reproduction in wet forest, Puerto Rico.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zimmerman, Jess K; Hogan, James Aaron; Nytch, Christopher J; Bithorn, John E</p> <p>2018-06-01</p> <p>Interannual changes in global climate and weather disturbances may influence reproduction in tropical forests. Phenomena such as the El Niño Southern Oscillation (ENSO) are known to produce interannual variation in reproduction, as do severe storms such as hurricanes. Using stationary trap-based phenology data collected fortnightly from 1993 to 2014 from a hurricane-affected (1989 Hugo, 1998 Georges) subtropical wet forest in northeastern Puerto Rico, we conducted a time series analysis of flowering and seed production. We addressed (1) the degree to which interannual variation in flower and seed production was influenced by global climate drivers and time since hurricane disturbance, and (2) how long-term trends in reproduction varied with plant lifeform. The seasonally de-trended number of species in flower fluctuated over time while the number of species producing seed exhibited a declining trend, one that was particularly evident during the second half of the study period. Lagged El Niño indices and time series hurricane disturbance jointly influenced the trends in numbers of flowering and fruiting species, suggesting complex global influences on tropical forest reproduction with variable periodicities. Lag times affecting flowering tended to be longer than those affecting fruiting. Long-term patterns of reproduction in individual lifeforms paralleled the community-wide patterns, with most groups of lifeform exhibiting a long-term decline in seed but not flower production. Exceptions were found for hemiepiphytes, small trees, and lianas whose seed reproduction increased and then declined over time. There was no long-term increase in flower production as reported in other Neotropical sites. © 2018 by the Ecological Society of America.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140017194','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140017194"><span>Trend Change Detection in NDVI Time Series: Effects of Inter-Annual Variability and Methodology</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Forkel, Matthias; Carvalhais, Nuno; Verbesselt, Jan; Mahecha, Miguel D.; Neigh, Christopher S.R.; Reichstein, Markus</p> <p>2013-01-01</p> <p>Changing trends in ecosystem productivity can be quantified using satellite observations of Normalized Difference Vegetation Index (NDVI). However, the estimation of trends from NDVI time series differs substantially depending on analyzed satellite dataset, the corresponding spatiotemporal resolution, and the applied statistical method. Here we compare the performance of a wide range of trend estimation methods and demonstrate that performance decreases with increasing inter-annual variability in the NDVI time series. Trend slope estimates based on annual aggregated time series or based on a seasonal-trend model show better performances than methods that remove the seasonal cycle of the time series. A breakpoint detection analysis reveals that an overestimation of breakpoints in NDVI trends can result in wrong or even opposite trend estimates. Based on our results, we give practical recommendations for the application of trend methods on long-term NDVI time series. Particularly, we apply and compare different methods on NDVI time series in Alaska, where both greening and browning trends have been previously observed. Here, the multi-method uncertainty of NDVI trends is quantified through the application of the different trend estimation methods. Our results indicate that greening NDVI trends in Alaska are more spatially and temporally prevalent than browning trends. We also show that detected breakpoints in NDVI trends tend to coincide with large fires. Overall, our analyses demonstrate that seasonal trend methods need to be improved against inter-annual variability to quantify changing trends in ecosystem productivity with higher accuracy.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.7547P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.7547P"><span>Long-term variability and changes in thunderstorm induced extreme precipitation in Slovakia over 1951-2010</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pecho, J.; Faško, P.; Bližák, V.; Kajaba, P.; Košálová, J.; Bochníček, O.; Lešková, L.</p> <p>2012-04-01</p> <p>It is well known that extreme precipitation associated with intensive rains, in summer induced mostly by local thunderstorm activity, could cause very significant problems in economical and social spheres of the countries. Heavy precipitation and consecutive flash-floods are the most serious weather-related hazards over the territory of Slovakia. The extreme precipitation analyses play a strategic role in many climatological and hydrological evaluations designed for the wide range of technical and engineering applications as well as climate change impact assessments. A thunderstorm, as a violent local storm produced by a cumulonimbus cloud and accompanied by thunder and lightning, represents extreme convective activity in the atmosphere depending upon the release of latent heat, by the condensation of water vapor, for most of its energy. Under the natural conditions of Slovakia the incidence of thunderstorms has been traditionally concentrated in the summer or warm half-year (Apr.-Sept.), but increasing air temperature resulting in higher water vapor content and more intense short-term precipitation is associated with more frequent thunderstorm occurrence in early spring as well as autumn. It is the main reason why the studies of thunderstorm phenomena have increased in Slovakia in recent years. It was found that thunderstorm occurrence, in terms of incidence of storm days, has profoundly changed particularly in spring season (~ 30 % in April and May). The present contribution is devoted to verifying the hypothesis that recently the precipitation has been more intense and significant shifts in seasonal incidence have occurred in particular regions in Slovakia. On the basis of the 60-year (1951-2010) meteorological observation series obtained from more than 20 synoptic stations, the analysis of trends and long-term variability of the days with thunderstorms and the accompanying precipitation for seasons was undertaken. Contribution also attempts to explain the main causes of the thunderstorm as well as extreme precipitation variability. Furthermore, differentiation of daily sums of precipitation for the days with thunderstorms, their long-term variability and probability of occurrence is also presented. Key words: thunderstorm occurrence, trend analysis, extreme precipitation, day with thunderstorm, climate change, climate variability, Slovakia</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C13A0936M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C13A0936M"><span>Long-term analyses of snow dynamics within the french Alps on the 1900-2100 period. Analyses of historical snow water equivalent observations, modelisations and projections of a hundred of snow courses.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mathevet, T.; Joel, G.; Gottardi, F.; Nemoz, B.</p> <p>2017-12-01</p> <p>The aim of this communication is to present analyses of climate variability and change on snow water equivalent (SWE) observations, reconstructions (1900-2016) and scenarii (2020-2100) of a hundred of snow courses dissiminated within the french Alps. This issue became particularly important since a decade, in regions where snow variability had a large impact on water resources availability, poor snow conditions in ski resorts and artificial snow production. As a water resources manager in french mountainuous regions, EDF (french hydropower company) has developed and managed a hydrometeorological network since 1950. A recent data rescue research allowed to digitize long term SWE manual measurments of a hundred of snow courses within the french Alps. EDF have been operating an automatic SWE sensors network, complementary to the snow course network. Based on numerous SWE observations time-series and snow accumulation and melt model (Garavaglia et al., 2017), continuous daily historical SWE time-series have been reconstructed within the 1950-2016 period. These reconstructions have been extented to 1900 using 20 CR reanalyses (ANATEM method, Kuentz et al., 2015) and up to 2100 using GIEC Climate Change scenarii. Considering various mountainous areas within the french Alps, this communication focuses on : (1) long term (1900-2016) analyses of variability and trend of total precipitation, air temperature, snow water equivalent, snow line altitude, snow season length , (2) long term variability of hydrological regime of snow dominated watersheds and (3) future trends (2020 -2100) using GIEC Climate Change scenarii. Comparing historical period (1950-1984) to recent period (1984-2016), quantitative results within a region in the north Alps (Maurienne) shows an increase of air temperature by 1.2 °C, an increase of snow line height by 200m, a reduction of SWE by 200 mm/year and a reduction of snow season length by 15 days. These analyses will be extended from north to south of the Alps, on a region spanning 200 km. Caracterisation of the increase of snow line height and SWE reduction are particularly important at a local and watershed scale. This long term change of snow dynamics within moutainuous regions both impacts snow resorts and artificial snow production developments and multi-purposes dam reservoirs managments.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMOS41B..01S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMOS41B..01S"><span>Sediment Transport Variability in Global Rivers: Implications for the Interpretation of Paleoclimate Signals</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Syvitski, J. P.; Hutton, E. W.</p> <p>2001-12-01</p> <p>A new numerical approach (HydroTrend, v.2) allows the daily flux of sediment to be estimated for any river, whether gauged or not. The model can be driven by actual climate measurements (precipitation, temperature) or with statistical estimates of climate (modeled climate, remotely-sensed climate). In both cases, the character (e.g. soil depth, relief, vegetation index) of the drainage terrain is needed to complete the model domain. The HydroTrend approach allows us to examine the effects of climate on the supply of sediment to continental margins, and the nature of supply variability. A new relationship is defined as: $Qs = f (Psi) Qs-bar (Q/Q-bar)c+-σ where Qs-bar is the long-term sediment load, Q-bar is the long-term discharge, c and sigma are mean and standard deviation of the inter-annual variability of the rating coefficient, and Psi captures the measurement errors associated with Q and Qs, and the annual transients, affecting the supply of sediment including sediment and water source, and river (flood wave) dynamics. F = F(Psi, s). Smaller-discharge rivers have larger values of s, and s asymptotes to a small but consistent value for larger-discharge rivers. The coefficient c is directly proportional to the long-term suspended load (Qs-bar) and basin relief (R), and inversely proportional to mean annual temperature (T). sigma is directly proportional to the mean annual discharge. The long-term sediment load is given by: Qs-bar = a R1.5 A0.5 TT $ where a is a global constant, A is basin area; and TT is a function of mean annual temperature. This new approach provides estimates of sediment flux at the dynamic (daily) level and provides us a means to experiment on the sensitivity of marine sedimentary deposits in recording a paleoclimate signal. In addition the method provides us with spatial estimates for the flux of sediment to the coastal zone at the global scale.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMGC51G0812C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMGC51G0812C"><span>A 320-year AMM+SOI Index Reconstruction from Historical Atlantic Tropical Cyclone Records</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chenoweth, M.; Divine, D.</p> <p>2010-12-01</p> <p>Trends in the frequency of North Atlantic tropical cyclones, including major hurricanes, are dominated by those originating in the deep tropics. In addition, these tropical cyclones are stronger when making landfall and their total power dissipation is higher than storms forming elsewhere in the Atlantic basin. Both the Atlantic Meridional Mode (AMM) and El Nino-Southern Oscillation (ENSO) are the leading modes of coupled air-sea interaction in the Atlantic and Pacific, respectively, and have well-established relationships with Atlantic hurricane variability. Here we use a 320-year record of tropical cyclone activity in the Lesser Antilles region of the North Atlantic from historical manuscript and newspaper records to reconstruct a normalized seasonal (July-October) index combining the Southern Oscillation Index (SOI) and AMM employing both the modern analog technique and back-propagation artificial neural networks. Our results indicate that the AMM+SOI index since 1690 shows no long-term trend but is dominated by both short-term (<10 years) and long-term (quasi-decadal to bi-decadal) variations. The decadal-scale variation is consistent with both instrumental and proxy records elsewhere from the global tropics. Distinct periods of high and low index values, corresponding to high and low tropical cyclone frequency, are regularly-appearing features in the record and provides further evidence that natural decadal -scale variability in Atlantic tropical cyclone frequency must be accounted for when determining trends in records and attribution of climate change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://rosap.ntl.bts.gov/view/dot/14118','DOTNTL'); return false;" href="https://rosap.ntl.bts.gov/view/dot/14118"><span>Long-term trends in railroad service and capacity for U.S. agriculture</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntlsearch.bts.gov/tris/index.do">DOT National Transportation Integrated Search</a></p> <p></p> <p>2000-11-01</p> <p>In this paper, the long-term trends in railroad services and capacity for U.S. agriculture are identified and described, particularly in terms of what these trends portend for agricultural shippers absent any change in the economically deregulated en...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4971236','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4971236"><span>Nonlinear stratospheric variability: multifractal de-trended fluctuation analysis and singularity spectra</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Domeisen, Daniela I. V.</p> <p>2016-01-01</p> <p>Characterizing the stratosphere as a turbulent system, temporal fluctuations often show different correlations for different time scales as well as intermittent behaviour that cannot be captured by a single scaling exponent. In this study, the different scaling laws in the long-term stratospheric variability are studied using multifractal de-trended fluctuation analysis (MF-DFA). The analysis is performed comparing four re-analysis products and different realizations of an idealized numerical model, isolating the role of topographic forcing and seasonal variability, as well as the absence of climate teleconnections and small-scale forcing. The Northern Hemisphere (NH) shows a transition of scaling exponents for time scales shorter than about 1 year, for which the variability is multifractal and scales in time with a power law corresponding to a red spectrum, to longer time scales, for which the variability is monofractal and scales in time with a power law corresponding to white noise. Southern Hemisphere (SH) variability also shows a transition at annual scales. The SH also shows a narrower dynamical range in multifractality than the NH, as seen in the generalized Hurst exponent and in the singularity spectra. The numerical integrations show that the models are able to reproduce the low-frequency variability but are not able to fully capture the shorter term variability of the stratosphere. PMID:27493560</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H11O..03S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H11O..03S"><span>A Global Drought and Flood Catalogue for the past 100 years</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sheffield, J.; He, X.; Peng, L.; Pan, M.; Fisher, C. K.; Wood, E. F.</p> <p>2017-12-01</p> <p>Extreme hydrological events cause the most impacts of natural hazards globally, impacting on a wide range of sectors including, most prominently, agriculture, food security and water availability and quality, but also on energy production, forestry, health, transportation and fisheries. Understanding how floods and droughts intersect, and have changed in the past provides the basis for understanding current risk and how it may change in the future. To do this requires an understanding of the mechanisms associated with events and therefore their predictability, attribution of long-term changes in risk, and quantification of projections of changes in the future. Of key importance are long-term records of relevant variables so that risk can be quantified more accurately, given the growing acknowledgement that risk is not stationary under long-term climate variability and climate change. To address this, we develop a catalogue of drought and flood events based on land surface and hydrodynamic modeling, forced by a hybrid meteorological dataset that draws from the continuity and coverage of reanalysis, and satellite datasets, merged with global gauge databases. The meteorological dataset is corrected for temporal inhomogeneities, spurious trends and variable inter-dependencies to ensure long-term consistency, as well as realistic representation of short-term variability and extremes. The VIC land surface model is run for the past 100 years at 0.25-degree resolution for global land areas. The VIC runoff is then used to drive the CaMa-Flood hydrodynamic model to obtain information on flood inundation risk. The model outputs are compared to satellite based estimates of flood and drought conditions and the observational flood record. The data are analyzed in terms of the spatio-temporal characteristics of large-scale flood and drought events with a particular focus on characterizing the long-term variability in risk. Significant changes in risk occur on multi-decadal time scales and are mostly associated with variability in the North Atlantic and Pacific. The catalogue can be used for analysis of extreme events, risk assessment, and as a benchmark for model evaluation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.A14E..06C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.A14E..06C"><span>The Impacts of Wind Speed Trends and Long-term Variability in Relation to Hydroelectric Reservoir Inflows on Wind Power in the Pacific Northwest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cross, B.; Kohfeld, K. E.; Cooper, A.; Bailey, H. J.; Rucker, M.</p> <p>2013-12-01</p> <p>The use of wind power is growing rapidly in the Pacific Northwest (PNW ) due to environmental concerns, decreasing costs of implementation, strong wind speeds, and a desire to diversify electricity sources to minimize the impacts of streamflow variability on electricity prices and system flexibility. In hydroelectric dominated systems, like the PNW, the benefits of wind power can be maximized by accounting for the relationship between long term variability in wind speeds and reservoir inflows. Clean energy policies in British Columbia make the benefits of increased wind power generation during low streamflow periods particularly large, by preventing the overbuilding of marginal hydroelectric projects. The goal of this work was to quantify long-term relationships between wind speed and streamflow behavior in British Columbia. Wind speed data from the North American Regional Reanalysis (NARR) and cumulative usable inflows (CUI) from BC Hydro were used to analyze 10m wind speed and density (WD) trends, WD-CUI correlations, and WD anomalies during low and high inflow periods in the PNW (40°N to 65°N, 110°W to 135°W) from 1979-2010. Statistically significant positive wind speed and density trends were found for most of the PNW, with the largest increases along the Pacific Coast. CUI-WD correlations were weakly positive for most regions, with the highest values along the US coast (r ~0.55), generally weaker correlations to the north, and negative correlations (r ~ -0.25) along BC's North Coast. When considering seasonal relationships, the Spring freshet was coincident with lower WD anomalies west of the Rocky Mountains and higher WDs to the east. A similar but opposite pattern was observed for low inflow winter months. When considering interannual variability, lowest inflow years experienced positive WD anomalies (up to 40% increases) for the North Coast. In highest inflow years, positive WD anomalies were widespread in the US and for smaller patches of central BC. By accounting for regional and temporal differences in the relationship between wind (WD) and streamflow (CUI) behaviour during wind farm site selection, the benefits of energy diversification can be maximized.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70018845','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70018845"><span>Spatial trends in Pearson Type III statistical parameters</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lichty, R.W.; Karlinger, M.R.</p> <p>1995-01-01</p> <p>Spatial trends in the statistical parameters (mean, standard deviation, and skewness coefficient) of a Pearson Type III distribution of the logarithms of annual flood peaks for small rural basins (less than 90 km2) are delineated using a climate factor CT, (T=2-, 25-, and 100-yr recurrence intervals), which quantifies the effects of long-term climatic data (rainfall and pan evaporation) on observed T-yr floods. Maps showing trends in average parameter values demonstrate the geographically varying influence of climate on the magnitude of Pearson Type III statistical parameters. The spatial trends in variability of the parameter values characterize the sensitivity of statistical parameters to the interaction of basin-runoff characteristics (hydrology) and climate. -from Authors</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRD..121.6943G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRD..121.6943G"><span>Variability of tornado occurrence over the continental United States since 1950</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guo, Li; Wang, Kaicun; Bluestein, Howard B.</p> <p>2016-06-01</p> <p>The United States experiences the most tornadoes of any country in the world. Given the catastrophic impact of tornadoes, concern has arisen regarding the variation in climatology of U.S. tornadoes under the changing climate. A recent study claimed that the temporal variability of tornado occurrence over the continental U.S. has increased since the 1970s. However, that study ignored the highly regionalized climatology of U.S. tornadoes. To address this issue, we examined the long-term trend of tornado temporal variability in each continental U.S. state. Based on the 64 year tornado records (1950-2013), we found that the trends in tornado temporal variability varied across the U.S., with only one third of the continental area or three out of 10 contiguous states (mostly from the Great Plains and Southeast, but where the frequency of occurrence of tornadoes is greater) displaying a significantly increasing trend. The other two-thirds area, where 60% of the U.S. tornadoes were reported (but the frequency of occurrence of tornadoes is less), however, showed a decreasing or a near-zero trend in tornado temporal variability. Furthermore, unlike the temporal variability alone, the combined spatial-temporal variability of U.S. tornado occurrence has remained nearly constant since 1950. Such detailed information on the climatological variability of U.S. tornadoes refines the claim of previous study and can be helpful for local mitigation efforts toward future tornado risks.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/75830-predicting-response-populations-environmental-change','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/75830-predicting-response-populations-environmental-change"><span>Predicting the response of populations to environmental change</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Ives, A.R.</p> <p>1995-04-01</p> <p>When subject to long-term directional environmental perturbations, changes in population densities depend on the positive and negative feedbacks operating through interactions within and among species in a community. This paper develops techniques to predict the long-term responses of population densities to environmental changes using data on short-term population fluctuations driven by short-term environmental variability. In addition to giving quantitative predictions, the techniques also reveal how different qualitative patterns of species interactions either buffer or accentuate population responses to environmental trends. All of the predictions are based on regression coefficients extracted from time series data, and they can therefore be appliedmore » with a minimum of mathematical and statistical gymnastics. 48 refs., 10 figs., 4 tabs.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1913842L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1913842L"><span>Relative importance of precipitation frequency and intensity in inter-annual variation of precipitation in Singapore during 1980-2013</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Xin; Babovic, Vladan</p> <p>2017-04-01</p> <p>Observed studies on inter-annual variation of precipitation provide insight into the response of precipitation to anthropogenic climate change and natural climate variability. Inter-annual variation of precipitation results from the concurrent variations of precipitation frequency and intensity, understanding of the relative importance of frequency and intensity in the variability of precipitation can help fathom its changing properties. Investigation of the long-term changes of precipitation schemes has been extensively carried out in many regions across the world, however, detailed studies of the relative importance of precipitation frequency and intensity in inter-annual variation of precipitation are still limited, especially in the tropics. Therefore, this study presents a comprehensive framework to investigate the inter-annual variation of precipitation and the dominance of precipitation frequency and intensity in a tropical urban city-state, Singapore, based on long-term (1980-2013) daily precipitation series from 22 rain gauges. First, an iterative Mann-Kendall trend test method is applied to detect long-term trends in precipitation total, frequency and intensity at both annual and seasonal time scales. Then, the relative importance of precipitation frequency and intensity in inducing the inter-annual variation of wet-day precipitation total is analyzed using a dominance analysis method based on linear regression. The results show statistically significant upward trends in wet-day precipitation total, frequency and intensity at annual time scale, however, these trends are not evident during the monsoon seasons. The inter-annual variation of wet-day precipitation is mainly dominated by precipitation intensity for most of the stations at annual time scale and during the Northeast monsoon season. However, during the Southwest monsoon season, the inter-annual variation of wet-day precipitation is mainly dominated by precipitation frequency. These results have implications for water resources management practices in Singapore.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ESD.....7..717G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ESD.....7..717G"><span>Coherence among the Northern Hemisphere land, cryosphere, and ocean responses to natural variability and anthropogenic forcing during the satellite era</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gonsamo, Alemu; Chen, Jing M.; Shindell, Drew T.; Asner, Gregory P.</p> <p>2016-08-01</p> <p>A lack of long-term measurements across Earth's biological and physical systems has made observation-based detection and attribution of climate change impacts to anthropogenic forcing and natural variability difficult. Here we explore coherence among land, cryosphere and ocean responses to recent climate change using 3 decades (1980-2012) of observational satellite and field data throughout the Northern Hemisphere. Our results show coherent interannual variability among snow cover, spring phenology, solar radiation, Scandinavian Pattern, and North Atlantic Oscillation. The interannual variability of the atmospheric peak-to-trough CO2 amplitude is mostly impacted by temperature-mediated effects of El Niño/Southern Oscillation (ENSO) and Pacific/North American Pattern (PNA), whereas CO2 concentration is affected by Polar Pattern control on sea ice extent dynamics. This is assuming the trend in anthropogenic CO2 emission remains constant, or the interannual changes in the trends are negligible. Our analysis suggests that sea ice decline-related CO2 release may outweigh increased CO2 uptake through longer growing seasons and higher temperatures. The direct effects of variation in solar radiation and leading teleconnections, at least in part via their impacts on temperature, dominate the interannual variability of land, cryosphere and ocean indicators. Our results reveal a coherent long-term changes in multiple physical and biological systems that are consistent with anthropogenic forcing of Earth's climate and inconsistent with natural drivers.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870033687&hterms=ozone+layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dozone%2Blayer','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870033687&hterms=ozone+layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dozone%2Blayer"><span>Instrument characterization for the detection of long-term changes in stratospheric ozone - An analysis of the SBUV/2 radiometer</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Frederick, J. E.; Heath, D. F.; Cebula, R. P.</p> <p>1986-01-01</p> <p>The scientific objective of unambiguously detecting subtle global trends in upper stratospheric ozone requires that one maintains a thorough understanding of the satellite-based remote sensors intended for this task. The instrument now in use for long term ozone monitoring is the SBUV/2 being flown on NOAA operational satellites. A critical activity in the data interpretation involves separating small changes in measurement sensitivity from true atmospheric variability. By defining the specific issues that must be addressed and presenting results derived early in the mission of the first SBUV/2 flight model, this work serves as a guide to the instrument investigations that are essential in the attempt to detect long-term changes in the ozone layer.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=235384&keyword=high+AND+flow+AND+oxygen&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=235384&keyword=high+AND+flow+AND+oxygen&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>Resolving drivers of variability in estuarine metabolism from sustained observations of water quality in the SE US</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>We examine trends in water quality in long-term monitoring (10-15 y) data collected at 5 estuarine systems of NOAA’s National Estuarine Research Reserve System: Grand Bay, MS; Weeks Bay, AL; Apalachicola Bay, FL; Rookery Bay, FL, and Guana Tolomatos and Matanzas Rivers, FL. These...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/44334','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/44334"><span>Conversion to pine: Changes in timing and magnitude of high and low flows.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Yusuf Serengil; Wayne T. Swank; Mark S. Riedel; James M. Vose</p> <p>2011-01-01</p> <p>Understanding watershed responses to extreme events is important for assessing potential impacts of floods, droughts, episodic pollution, and other external driving variables on watershed resources. In this study, we combine trend and frequency analyses with paired watershed techniques to evaluate the long-term high- and low-flow data from Coweeta Hydrologic Laboratory...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AAS...22924012V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AAS...22924012V"><span>Tuning Into Brown Dwarfs: Long-Term Radio Monitoring of Two Very Low Mass Dwarfs</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Van Linge, Russell; Burgasser, Adam J.; Melis, Carl; Williams, Peter K. G.</p> <p>2017-01-01</p> <p>The very lowest-mass (VLM) stars and brown dwarfs, with effective temperatures T < 3000 K, exhibit mixed magnetic activity trends, with H-alpha and X-ray emission that declines rapidly beyond type M7/M8, but persistent radio emission in roughly 10-20% of sources. The dozen or so VLM radio emitters known show a broad range of emission characteristics and time-dependent behavior, including steady persistent emission, periodic oscillations, periodic polarized bursts, and aperiodic flares. Understanding the evolution of these variability patterns, and in particular whether they undergo solar-like cycles, requires long-term monitoring. We report the results of a long-term JVLA monitoring program of two magnetically-active VLM dwarf binaries, the young M7 2MASS 1314+1320AB and older L5 2MASS 1315-2649AB. On the bi-weekly cadence, 2MASS 1314 continues to show variability by revealing regular flaring while 2MASS 1315 continues to be a quiescent emitter. On the daily time scale, both sources show a mean flux density that can vary significantly just over a few days. These results suggest long-term radio behavior in radio-emitting VLM dwarfs is just as diverse and complex as short-term behavior.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11950544','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11950544"><span>Long-term trends in sunshine duration and its association with schizophrenia birth rates and age at first registration--data from Australia and the Netherlands.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McGrath, John; Selten, Jean-Paul; Chant, David</p> <p>2002-04-01</p> <p>Based on the well-described excess of schizophrenia births in winter and spring, we hypothesised that individuals with schizophrenia (a) would be more likely to be born during periods of decreased perinatal sunshine, and (b) those born during periods of less sunshine would have an earlier age of first registration. We undertook an ecological analysis of long-term trends in perinatal sunshine duration and schizophrenia birth rates based on two mental health registers (Queensland, Australia n=6630; The Netherlands n=24,474). For each of the 480 months between 1931 and 1970, the agreement between slopes of the trends in psychosis and long-term sunshine duration series were assessed. Age at first registration was assessed by quartiles of long-term trends in perinatal sunshine duration. Males and females were assessed separately. Both the Dutch and Australian data showed a statistically significant association between falling long-term trends in sunshine duration around the time of birth and rising schizophrenia birth rates for males only. In both the Dutch and Australian data there were significant associations between earlier age of first registration and reduced long-term trends in sunshine duration around the time of birth for both males and females. A measure of long-term trends in perinatal sunshine duration was associated with two epidemiological features of schizophrenia in two separate data sets. Exposures related to sunshine duration warrant further consideration in schizophrenia research.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70192580','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70192580"><span>Patterns and predictability in the intra-annual organic carbon variability across the boreal and hemiboreal landscape</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hytteborn, Julia K.; Temnerud, Johan; Alexander, Richard B.; Boyer, Elizabeth W.; Futter, Martyn N.; Fröberg, Mats; Dahné, Joel; Bishop, Kevin H.</p> <p>2015-01-01</p> <p>Factors affecting total organic carbon (TOC) concentrations in 215 watercourses across Sweden were investigated using parameter parsimonious regression approaches to explain spatial and temporal variabilities of the TOC water quality responses. We systematically quantified the effects of discharge, seasonality, and long-term trend as factors controlling intra-annual (among year) and inter-annual (within year) variabilities of TOC by evaluating the spatial variability in model coefficients and catchment characteristics (e.g. land cover, retention time, soil type).Catchment area (0.18–47,000 km2) and land cover types (forests, agriculture and alpine terrain) are typical for the boreal and hemiboreal zones across Fennoscandia. Watercourses had at least 6 years of monthly water quality observations between 1990 and 2010. Statistically significant models (p < 0.05) describing variation of TOC in streamflow were identified in 209 of 215 watercourses with a mean Nash-Sutcliffe efficiency index of 0.44. Increasing long-term trends were observed in 149 (70%) of the watercourses, and intra-annual variation in TOC far exceeded inter-annual variation. The average influences of the discharge and seasonality terms on intra-annual variations in daily TOC concentration were 1.4 and 1.3 mg l− 1 (13 and 12% of the mean annual TOC), respectively. The average increase in TOC was 0.17 mg l− 1 year− 1 (1.6% year− 1).Multivariate regression with over 90 different catchment characteristics explained 21% of the spatial variation in the linear trend coefficient, less than 20% of the variation in the discharge coefficient and 73% of the spatial variation in mean TOC. Specific discharge, water residence time, the variance of daily precipitation, and lake area, explained 45% of the spatial variation in the amplitude of the TOC seasonality.Because the main drivers of temporal variability in TOC are seasonality and discharge, first-order estimates of the influences of climatic variability and change on TOC concentration should be predictable if the studied catchments continue to respond similarly.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004cosp...35.1818S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004cosp...35.1818S"><span>The features of chlorophyll concentration long-standing dynamics in the ocean surface layer (comparison of czcs and seawifs data)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shevyrnogov, A.; Vysotskaya, G.</p> <p></p> <p>To preserve biosphere and make its utilization expedient makes imperative to comprehend in depth long-standing dynamics of the primary production process on our planet. Variability of chlorophyll concentration in the ocean is one of the most important components of this process. However, hard access and large size of the water surface make its investigation labor-consuming. Besides, the dependence of primary production on high variability of hydrophysical phenomena in the ocean (fluctuations of currents, frontal zones, etc.) makes the location of points for measuring the chlorophyll concentration dynamics significant. In this work the long-standing changes in chlorophyll concentration in the surface layer of the ocean have been analyzed on the basis of the CZCS data for 7.5 years and the SeaWiFS data from 1997 to 2003. It was shown that the average chlorophyll concentration calculated at all investigated area is varied moderately. However when analyzing spatially local trends, it was detected that areas exist with stable rise and fall of chlorophyll concentration. Some interesting features of the long-standing dynamics of chlorophyll concentration several interesting features were found. There are the various directions of long-term trends (constant increase or decrease) that cannot be explained only by large-scale hydrological phenomena in the ocean (currents, upwellings etc.). The next feature is a difference between the trends revealed by using the CZCS data and the trends based on the SeaWiFS data. Thus, the obtained results allow the possibility of identification of the ocean biota role in the global biospheric gas exchange.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1913848J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1913848J"><span>Gained insights from combined high-frequency and long-term water quality monitoring in agricultural catchments</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jomaa, Seifeddine; Dupas, Rémi; Musolff, Andreas; Rozemeijer, Joachim; Borchardt, Dietrich; Rode, Michael</p> <p>2017-04-01</p> <p>Despite extensive efforts to reduce nitrate (NO3) transfer in agricultural areas, the NO3 concentration in rivers often changes little. To investigate the reasons for this limited response, NO3 dynamics in a 100 km2 agricultural catchment in eastern Germany was analysed from decadal to infra-hourly time scales. First, Dynamic Harmonic Regression (DHR) analysis of a 32-year (1982-2014) record of NO3 and discharge revealed that i) the long-term trend in NO3 concentration was closely related to that in discharge, suggesting that large-scale weather and climate patterns were masking the effect of improved nitrogen management on NO3 trends; ii) maximum winter and minimum summer concentrations had a persistent seasonal pattern, which was interpreted as a dynamic NO3 concentration from the soil and subsoil columns; and iii) the catchment progressively changed from chemodynamic to more chemostatic behaviour over the three decades of study, which is a sign of long-term homogenisation of NO3 concentrations in the profile. Second, infra-hourly (15 min time interval) analysis of storm-event dynamics during a typical hydrological year (2005-2006) was performed to identify periods of the year with high leaching risk and to link the latter to agricultural management practices in the catchment. Also, intra-hourly data was used to improve NO3 load estimation during storm events. An Event Response Reconstruction (ERR) model was built using NO3 concentration response descriptor variables and predictor variables deduced from discharge and precipitation records. The ERR approach significantly improved NO3 load estimates compared to linear interpolation of grab-sampling data (error was reduced from 10 to 1%). Finally, this study shows that detailed physical understanding of NO3 dynamics across time scales can be obtained only through combined analysis of long-term records and high-resolution sensor data. Hence, a joint effort is advocated between environmental authorities, who usually perform long-term monitoring, and scientific programmes, which usually perform high-resolution monitoring.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12965035','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12965035"><span>Life-history strategies associated with local population variability confer regional stability.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pribil, Stanislav; Houlahan, Jeff E</p> <p>2003-07-07</p> <p>A widely held ecological tenet is that, at the local scale, populations of K-selected species (i.e. low fecundity, long lifespan and large body size) will be less variable than populations of r-selected species (i.e. high fecundity, short lifespan and small body size). We examined the relationship between long-term population trends and life-history attributes for 185 bird species in the Czech Republic and found that, at regional spatial scales and over moderate temporal scales (100-120 years), K-selected bird species were more likely to show both large increases and decreases in population size than r-selected species. We conclude that life-history attributes commonly associated with variable populations at the local scale, confer stability at the regional scale.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AtmRe.169..357M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AtmRe.169..357M"><span>Changes in the type of precipitation and associated cloud types in Eastern Romania (1961-2008)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Manea, Ancuta; Birsan, Marius-Victor; Tudorache, George; Cărbunaru, Felicia</p> <p>2016-03-01</p> <p>Recent climate change is characterized (among other things) by changes in the frequency of some meteorological phenomena. This paper deals with the long-term changes in various precipitation types, and the connection between their variability and cloud type frequencies, at 11 meteorological stations from Eastern Romania over 1961-2008. These stations were selected with respect to data record completeness for all considered variables (weather phenomena and cloud type). The meteorological variables involved in the present study are: monthly number of days with rain, snowfall, snow showers, rain and snow (sleet), sleet showers and monthly frequency of the Cumulonimbus, Nimbostratus and Stratus clouds. Our results show that all stations present statistically significant decreasing trends in the number of days with rain in the warm period of the year. Changes in the frequency of days for each precipitation type show statistically significant decreasing trends for non-convective (stratiform) precipitation - rain, drizzle, sleet and snowfall -, while the frequencies of rain shower and snow shower (convective precipitation) are increasing. Cloud types show decreasing trends for Nimbostratus and Stratus, and increasing trends for Cumulonimbus.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ACPD...14.1073Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ACPD...14.1073Z"><span>Evidence for an earlier greenhouse cooling effect in the stratosphere before the 1980s over the Northern Hemisphere</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zerefos, C. S.; Tourpali, K.; Zanis, P.; Eleftheratos, K.; Repapis, C.; Goodman, A.; Wuebbles, D.; Isaksen, I. S. A.; Luterbacher, J.</p> <p>2014-01-01</p> <p>This study provides a new look at the observed and calculated long-term temperature changes since 1958 for the region extending from the lower troposphere up to the lower stratosphere of the Northern Hemisphere. The analysis is mainly based on monthly layer mean temperatures derived from geopotential height thicknesses between specific pressure levels. Layer mean temperatures from thickness improve homogeneity in both space and time and reduce uncertainties in the trend analysis. Datasets used include the NCEP/NCAR I reanalysis, the Free University of Berlin (FU-Berlin) and the RICH radiosonde datasets as well as historical simulations with the CESM1-WACCM global model participating in CMIP5. After removing the natural variability with an autoregressive multiple regression model our analysis shows that the time interval of our study 1958-2011 can be divided in two distinct sub-periods of long term temperature variability and trends; before and after 1980s. By calculating trends for the summer time to reduce interannual variability, the two periods are as follows. From 1958 until 1979, non-significant trends or slight cooling trends prevail in the lower troposphere (0.06 ± 0.06 °C decade-1 for NCEP and -0.12 ± 0.06 °C decade-1 for RICH). The second period from 1980 to the end of the records shows significant warming trends (0.25 ± 0.05 °C decade-1 for both NCEP and RICH). Above the tropopause a persistent cooling trend is clearly seen in the lower stratosphere both in the pre-1980s period (-0.58 ± 0.17 °C decade-1 for NCEP, -0.30 ± 0.16 °C decade-1 for RICH and -0.48 ± 0.20 °C decade-1 for FU-Berlin) and the post-1980s period (-0.79 ± 0.18 °C decade-1 for NCEP, -0.66 ± 0.16 °C decade-1 for RICH and -0.82 ± 0.19 °C decade-1 for FU-Berlin). The cooling in the lower stratosphere is a persistent feature from the tropics up to 60 north for all months. At polar latitudes competing dynamical and radiative processes are reducing the statistical significance of these trends. Model results are in line with re-analysis and the observations, indicating a persistent cooling in the lower stratosphere during summer before and after the 1980s by -0.33 °C decade-1; a feature that is also seen throughout the year. However, the lower stratosphere modelled trends are generally lower than re-analysis and the observations. The contrasting effects of ozone depletion at polar latitudes in winter/spring and the anticipated strengthening of the Brewer Dobson circulation from man-made global warming at polar latitudes are discussed. Our results provide additional evidence for an early greenhouse cooling signal in the lower stratosphere before the 1980s, which it appears well in advance relative to the tropospheric greenhouse warming signal. Hence it may be postulated that the stratosphere could have provided an early warning of man-made climate change. The suitability for early warning signals in the stratosphere relative to the troposphere is supported by the fact that the stratosphere is less sensitive to changes due to cloudiness, humidity and man-made aerosols. Our analysis also indicates that the relative contribution of the lower stratosphere vs. the upper troposphere low frequency variability is important for understanding the added value of the long term tropopause variability related to human induced global warming.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ACP....14.7059C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ACP....14.7059C"><span>Total ozone trends and variability during 1979-2012 from merged data sets of various satellites</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chehade, W.; Weber, M.; Burrows, J. P.</p> <p>2014-07-01</p> <p>The study presents a long-term statistical trend analysis of total ozone data sets obtained from various satellites. A multi-variate linear regression was applied to annual mean zonal mean data using various natural and anthropogenic explanatory variables that represent dynamical and chemical processes which modify global ozone distributions in a changing climate. The study investigated the magnitude and zonal distribution of the different atmospheric chemical and dynamical factors contributing to long-term total ozone changes. The regression model included the equivalent effective stratospheric chlorine (EESC), the 11-year solar cycle, the quasi-biennial oscillation (QBO), stratospheric aerosol loading describing the effects from major volcanic eruptions, the El Niño-Southern Oscillation (ENSO), the Arctic and Antarctic oscillation (AO/AAO), and accumulated eddy heat flux (EHF), the latter representing changes due to the Brewer-Dobson circulation. The total ozone column data set used here comprises the Solar Backscater Ultraviolet SBUV/SBUV-2 merged ozone data set (MOD) V8.6, the merged data set of the Solar Backscaterr Ultraviolet, the Total Ozone Mapping Spectrometer and the Ozone Monitoring Instrument SBUV/TOMS/OMI (1979-2012) MOD V8.0 and the merged data set of the Global Ozone Monitoring Experiment, the Scanning Imaging Absorption spectroMeter for Atmospheric ChartograpHY and the Global Ozone Monitoring Experiment 2 GOME/SCIAMACHY/GOME-2 (GSG) (1995-2012). The trend analysis was performed for twenty-six 5° wide latitude bands from 65° S to 65° N, and the analysis explained most of the ozone variability to within 70 to 90%. The results show that QBO dominates the ozone variability in the tropics (±7 DU) while at higher latitudes, the dynamical indices, AO/AAO and eddy heat flux, have substantial influence on total ozone variations by up to ±10 DU. The contribution from volcanic aerosols is only prominent during the major eruption periods (El Chichón and Mt. Pinatubo), and together with the ENSO signal, is more evident in the Northern Hemisphere. The signature of the solar cycle covers all latitudes and contributes about 10 DU from solar maximum to solar minimum. EESC is found to be a main contributor to the long-term ozone decline and the trend changes after the end of the 1990s. From the EESC fits, statistically significant upward trends after 1997 were found in the extratropics, which points at the slowing of ozone decline and the onset of ozone recovery. The EESC based trends are compared with the trends obtained from the statistical piecewise linear trend (PWLT) model (known as hockey stick) with a turnaround in 1997 to examine the differences between both approaches. In case of the SBUV merged V8.6 data the EESC and PWLT trends before and after 1997 are in good agreement (within 2 σ), however, the positive post-1997 linear trends from the PWLT regression are not significant within 2 σ. A sensitivity study is carried out by comparing the regression results, using SBUV/SBUV-2 MOD V8.6 merged time series (1979-2012) and a merged data set combining SBUV/SBUV-2 (1979-June 1995) and GOME/SCIAMACHY/GOME-2 ("GSG") WFDOAS (Weighting Function DOAS) (July 1995-2012) as well as SBUV/TOMS/OMI MOD V8.0 (1979-2012) in the regression analysis in order to investigate the uncertainty in the long-term trends due to different ozone data sets and data versions. Replacing the late SBUV/SBUV-2 merged data record with GSG data (unscaled and adjusted) leads to very similar results demonstrating the high consistency between satellite data sets. However, the comparison of the new SBUV/SBUV-2 MOD V8.6 with the MOD V8.0 and MOD8.6/GSG data showed somewhat smaller sensitivities with regard to several proxies as well as the linear EESC trends. On the other hand, the PWLT trends after 1997 show some differences, however, within the 2 σ error bars the PWLT trends agree with each other for all three data sets.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150001526','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150001526"><span>Reevaluation of Stratospheric Ozone Trends From SAGE II Data Using a Simultaneous Temporal and Spatial Analysis</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Damadeo, R. P.; Zawodny, J. M.; Thomason, L. W.</p> <p>2014-01-01</p> <p>This paper details a new method of regression for sparsely sampled data sets for use with time-series analysis, in particular the Stratospheric Aerosol and Gas Experiment (SAGE) II ozone data set. Non-uniform spatial, temporal, and diurnal sampling present in the data set result in biased values for the long-term trend if not accounted for. This new method is performed close to the native resolution of measurements and is a simultaneous temporal and spatial analysis that accounts for potential diurnal ozone variation. Results show biases, introduced by the way data is prepared for use with traditional methods, can be as high as 10%. Derived long-term changes show declines in ozone similar to other studies but very different trends in the presumed recovery period, with differences up to 2% per decade. The regression model allows for a variable turnaround time and reveals a hemispheric asymmetry in derived trends in the middle to upper stratosphere. Similar methodology is also applied to SAGE II aerosol optical depth data to create a new volcanic proxy that covers the SAGE II mission period. Ultimately this technique may be extensible towards the inclusion of multiple data sets without the need for homogenization.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JApA...39...30L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JApA...39...30L"><span>Multiband optical-IR variability of the blazar PKS 0537-441</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Xiao-Pan; Wang, Li-Sha; Yang, Cheng; Yang, Hai-yan; Zhou, Li; Xu, Guang-Yang; Shan, Yu-Qiong; Liu, Jie; Luo, Yu-Hui; Zhang, Li</p> <p>2018-06-01</p> <p>We have reconsidered the simultaneous and homogeneous optical-IR light curves and the corresponding spectral indices curve of the blazar PKS 0537-441 from January 2011 to May 2015. All the curves show significant fluctuations on various timescales, and the flux variations seem to be more pronounced towards the IR bands. The relation between average fluxes and spectral indices reveals the existence of redder-when-brighter (RWB) and bluer-when-brighter (BWB) trends at different flux levels, along with a long-term achromatic trend and a mild RWB trend on short-term timescales. Cross-correlation analyses present an energy-dependent time delay that the lower-frequency variations follow higher-frequency ones by a few weeks and a hysteresis pattern between spectra and fluxes. Our analysis reveals some potential coherence between low-energy-peaked BL Lacs (LBLs) and FSRQs, and indicates that the observed flux variability and spectral changes could be due to the superposition of a dominant jet emission, an underlying thermal contribution from a more slowly varying disk and/or other geometric effects under the shock-in-jet scenario.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PrOce..97..152L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PrOce..97..152L"><span>Long-term variability and environmental preferences of calycophoran siphonophores in the Bay of Villefranche (north-western Mediterranean)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Licandro, P.; Souissi, S.; Ibanez, F.; Carré, C.</p> <p>2012-05-01</p> <p>Long-term variability of the main calycophoran siphonophores was investigated between 1974 and 1999 in a coastal station in the north-western Mediterranean. The data were collected at weekly frequency using a macroplankton net (680 μm mesh size) adapted to quantitatively sample delicate gelatinous plankton. A 3-year collection (1967-1969) of siphonophores from offshore waters using the same methodology showed that the patterns of variability observed inshore were representative of siphonophores’ changes at a regional scale. The aims of the study were: (i) to investigate the patterns of variability that characterised the dominant calycophoran species and assemblages; (ii) to identify the environmental optima that were associated with a significant increase in the dominant siphonophore species and (iii) to verify the influence of hydroclimatic variability on long-term changes of siphonophores. Our results showed that during nearly 3 decades the standing stock of calycophoran siphonophores did not show any significant change, with the annual maximum usually recorded in spring as a result of high densities of the dominant species Lensia subtilis, Muggiaea kochi and Muggiaea atlantica. Nevertheless, major changes in community composition occurred within the calycophoran population. Since the middle 1980s, M. kochi, once the most dominant species, started to decrease allowing other species, the congeneric M. atlantica and Chelophyes appendiculata, to increasingly dominate in spring and summer-autumn, respectively. The comparison of environmental and biotic long-term trends suggests that the decrease of M. kochi was triggered by hydrological changes that occurred in the north-western Mediterranean under the forcing of large-scale climate oscillations. Salinity, water stratification and water temperature were the main hydroclimatic factors associated with a significant increase of siphonophores, different species showing different environmental preferences.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018GPC...161..172P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018GPC...161..172P"><span>Identification of trend in long term precipitation and reference evapotranspiration over Narmada river basin (India)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pandey, Brij Kishor; Khare, Deepak</p> <p>2018-02-01</p> <p>Precipitation and reference evapotranspiration are key parameters in hydro-meteorological studies and used for agricultural planning, irrigation system design and management. Precipitation and evaporative demand are expected to be alter under climate change and affect the sustainable development. In this article, spatial variability and temporal trend of precipitation and reference evapotranspiration (ETo) were investigated over Narmada river basin (India), a humid tropical climatic region. In the present study, 12 and 28 observatory stations were selected for precipitation and ETo, respectively of 102-years period (1901-2002). A rigorous analysis for trend detection was carried out using non parametric tests such as Mann-Kendall (MK) and Spearman Rho (SR). Sen's slope estimator was used to analyze the rate of change in long term series. Moreover, all the stations of basin exhibit positive trend for annual ETo, while 8% stations indicate significant negative trend for mean annual precipitation, respectively. Change points of annual precipitation were identified around the year 1962 applying Buishand's and Pettit's test. Annual mean precipitation reduced by 9% in upper part while increased maximum by 5% in lower part of the basin due temporal changes. Although annual mean ETo increase by 4-12% in most of the region. Moreover, results of the study are very helpful in planning and development of agricultural water resources.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1436070','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1436070"><span>Seasonal Trends of Soiling on Photovoltaic Systems: Preprint</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Muller, Matthew T; Ruth, Daniel; Micheli, Leonardo</p> <p></p> <p>This work investigates the seasonal variability of PV soiling losses over a 12-month period for sixteen soiling stations deployed in the USA. A new parameter able to rank the sites according to the cumulative losses occurring over 3- and 6- month periods is presented. The relations between soiling losses and particulate matter are briefly discussed as well. Moving from long-term to shorter-term data increases the complexity of the analysis: monthly correlations are found to have lower accuracy than the longer term ones presented in the literature.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28258340','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28258340"><span>Variability, trends, and teleconnections of stream flows with large-scale climate signals in the Omo-Ghibe River Basin, Ethiopia.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Degefu, Mekonnen Adnew; Bewket, Woldeamlak</p> <p>2017-04-01</p> <p>This study assesses variability, trends, and teleconnections of stream flow with large-scale climate signals (global sea surface temperatures (SSTs)) for the Omo-Ghibe River Basin of Ethiopia. Fourteen hydrological indices of variability and extremes were defined from daily stream flow data series and analyzed for two common periods, which are 1972-2006 for 5 stations and 1982-2006 for 15 stations. The Mann-Kendall's test was used to detect trends at 0.05 significance level, and simple correlation analysis was applied to evaluate associations between the selected stream flow indices and SSTs. We found weak and mixed (upward and downward) trend signals for annual and wet (Kiremt) season flows. Indices generated for high-flow (flood) magnitudes showed the same weak trend signals. However, trend tests for flood frequencies and low-flow magnitudes showed little evidences of increasing change. It was also found that El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) are the major anomalies affecting stream flow variability in the Omo-Ghibe Basin. The strongest associations are observed between ENSO/Niño3.4 and the stream flow in August and September, mean Kiremt flow (July-September), and flood frequency (peak over threshold on average three peaks per year (POT3_Fre)). The findings of this study provide a general overview on the long-term stream flow variability and predictability of stream flows for the Omo-Ghibe River Basin.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.S41C0790N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.S41C0790N"><span>Exploring Low-Amplitude, Long-Duration Deformational Transients on the Cascadia Subduction Zone</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nuyen, C.; Schmidt, D. A.</p> <p>2017-12-01</p> <p>The absence of long-term slow slip events (SSEs) in Cascadia is enigmatic on account of the diverse group of subduction zone systems that do experience long-term SSEs. In particular, southwest Japan, Alaska, New Zealand and Mexico have observed long-term SSEs, with some of the larger events exhibiting centimeter-scale surface displacements over the course of multiple years. The conditions that encourage long-term slow slip are not well established due to the variability in thermal parameter and plate dip amongst subduction zones that host long-term events. The Cascadia Subduction Zone likely has the capacity to host long-term SSEs, and the lack of such events motivates further exploration of the observational data. In order to search for the existence of long-duration transients in surface displacements, we examine Cascadia GPS time series from PANGA and PBO to determine whether or not Cascadia has hosted a long-term slow slip event in the past 20 years. A careful review of the time series does not reveal any large-scale multi-year transients. In order to more clearly recognize possible small amplitude long-term SSEs in Cascadia, the GPS time series are reduced with two separate methods. The first method involves manually removing (1) continental water loading terms, (2) transient displacements of known short-term SSEs, and (3) common mode signals that span the network. The second method utilizes a seasonal-trend decomposition procedure (STL) to extract a long-term trend from the GPS time-series. Manual inspection of both of these products reveals intriguing long-term changes in the longitudinal component of several GPS stations in central Cascadia. To determine whether these shifts could be due to long-term slow slip, we invert the reduced surface displacement time series for fault slip using a principle component analysis-based inversion method. We also utilize forward fault models of various synthetic long-term SSEs to better understand how these events may appear in the time series for a range of magnitudes and durations. Results from this research have direct implications for the possible slip modes in Cascadia and how variations in slip over time can impact stress and strain accumulations along the margin.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H13M..01H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H13M..01H"><span>Spatial variations in drainage efficiency in a boreal wetland environment as a function of lidar and radar-derived deviations from the regional hydraulic gradient</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hopkinson, C.; Brisco, B.; Chasmer, L.; Devito, K.; Montgomery, J. S.; Patterson, S.; Petrone, R. M.</p> <p>2017-12-01</p> <p>The dense forest cover of the Western Boreal Plains of northern Alberta is underlain by a mix of glacial moraines, sandy outwash sediments and clay plains possessing spatially variable hydraulic conductivities. The region is also characterised by a large number of post-glacial surface depression wetlands that have seasonally and topographically limited surface connectivity. Consequently, drainage along shallow regional hydraulic gradients may be dominated either by variations in surface geology or local variations in Et. Long-term government lake level monitoring is sparse in this region, but over a decade of hydrometeorological monitoring has taken place around the Utikuma Regional Study Area (URSA), a research site led by the University of Alberta. In situ lake and ground water level data are here combined with time series of airborne lidar and RadarSat II synthetic aperture radar (SAR) data to assess the spatial variability of water levels during late summer period characterised by flow recession. Long term Lidar data were collected or obtained by the authors in August of 2002, 2008, 2011 and 2016, while seasonal SAR data were captured approximately every 24 days during the summers of 2015, 2016 and 2017. Water levels for wetlands exceeding 100m2 in area across a north-trending 20km x 5km topographic gradient north of Utikuma Lake were extracted directly from the lidar and indirectly from the SAR. The recent seasonal variability in spatial water levels was extracted from SAR, while the lidar data illustrated more long term trends associated with land use and riparian vegetation succession. All water level data collected in August were combined and averaged at multiple scales using a raster focal statistics function to generate a long term spatial map of the regional hydraulic gradient and scale-dependent variations. Areas of indicated high and low drainage efficiency were overlain onto layers of landcover and surface geology to ascertain causal relationships. Areas associated with high spatial variability in water level illustrate reduced drainage connectivity, while areas of reduced variability indicate high surface connectivity and/or hydraulic conductivity. The hypothesis of surface geology controls on local wetland connectivity and landscape drainage efficiency is supported through this analysis.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140012675','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140012675"><span>Solar Spectral Irradiance Changes During Cycle 24</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Marchenko, Sergey; Deland, Matthew</p> <p>2014-01-01</p> <p>We use solar spectra obtained by the Ozone Monitoring Instrument (OMI) on board the Aura satellite to detect and follow long-term (years) and short-term (weeks) changes in the solar spectral irradiance (SSI) in the 265-500 nm spectral range. During solar Cycle 24, in the relatively line-free regions the SSI changed by approximately 0.6% +/- 0.2% around 265 nm. These changes gradually diminish to 0.15% +/- 0.20% at 500 nm. All strong spectral lines and blends, with the notable exception of the upper Balmer lines, vary in unison with the solar "continuum." Besides the lines with strong chromospheric components, the most involved species include Fe I blends and all prominent CH, NH, and CN spectral bands. Following the general trend seen in the solar "continuum," the variability of spectral lines also decreases toward longer wavelengths. The long-term solar cycle SSI changes are closely, to within the quoted 0.1%-0.2% uncertainties, matched by the appropriately adjusted short-term SSI variations derived from the 27 day rotational modulation cycles. This further strengthens and broadens the prevailing notion about the general scalability of the UV SSI variability to the emissivity changes in the Mg II 280 nm doublet on timescales from weeks to years. We also detect subtle deviations from this general rule: the prominent spectral lines and blends at lambda approximately or greater than 350 nm show slightly more pronounced 27 day SSI changes when compared to the long-term (years) trends. We merge the solar data from Cycle 21 with the current Cycle 24 OMI and GOME-2 observations and provide normalized SSI variations for the 170-795 nm spectral region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5225474','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5225474"><span>Long-term MODIS observations of cyanobacterial dynamics in Lake Taihu: Responses to nutrient enrichment and meteorological factors</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Shi, Kun; Zhang, Yunlin; Zhou, Yongqiang; Liu, Xiaohan; Zhu, Guangwei; Qin, Boqiang; Gao, Guang</p> <p>2017-01-01</p> <p>We developed and validated an empirical model for estimating chlorophyll a concentrations (Chla) in Lake Taihu to generate a long-term Chla and algal bloom area time series from MODIS-Aqua observations for 2003 to 2013. Then, based on the long-term time series data, we quantified the responses of cyanobacterial dynamics to nutrient enrichment and climatic conditions. Chla showed substantial spatial and temporal variability. In addition, the annual mean cyanobacterial surface bloom area exhibited an increasing trend across the entire lake from 2003 to 2013, with the exception of 2006 and 2007. High air temperature and phosphorus levels in the spring can prompt cyanobacterial growth, and low wind speeds and low atmospheric pressure levels favor cyanobacterial surface bloom formation. The sensitivity of cyanobacterial dynamics to climatic conditions was found to vary by region. Our results indicate that temperature is the most important factor controlling Chla inter-annual variability followed by phosphorus and that air pressure is the most important factor controlling cyanobacterial surface bloom formation followed by wind speeds in Lake Taihu. PMID:28074871</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2018/1038/ofr20181038.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2018/1038/ofr20181038.pdf"><span>Factors affecting long-term trends in surface-water quality in the Gwynns Falls watershed, Baltimore City and County, Maryland, 1998–2016</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Majcher, Emily H.; Woytowitz, Ellen L.; Reisinger, Alexander J.; Groffman, Peter M.</p> <p>2018-03-30</p> <p>Factors affecting water-quality trends in urban streams are not well understood, despite current regulatory requirements and considerable ongoing investments in gray and green infrastructure. To address this gap, long-term water-quality trends and factors affecting these trends were examined in the Gwynns Falls, Maryland, watershed during 1998–2016 in cooperation with Blue Water Baltimore. Data on water-quality constituents and potential factors of influence were obtained from multiple sources and compiled for analysis, with a focus on data collected as part of the National Science Foundation funded Long-Term Ecological Research project, the Baltimore Ecosystem Study.Variability in climate (specifically, precipitation) and land cover can overwhelm actions taken to improve water quality and can present challenges for meeting regulatory goals. Analysis of land cover during 2001–11 in the Gwynns Falls watershed indicated minimal change during the study time frame; therefore, land-cover change is likely not a factor affecting trends in water quality. However, a modest increase in annual precipitation and a significant increase in winter precipitation were apparent in the region. A higher proportion of runoff producing storms was observed in the winter and a lower proportion in the summer, indicating that climate change may affect water quality in the watershed. The increase in precipitation was not reflected in annual or seasonal trends of streamflow in the watershed. Nonetheless, these precipitation changes may exacerbate the inflow and infiltration of water to gray infrastructure and reduce the effectiveness of green infrastructure. For streamflow and most water-quality constituents examined, no discernable trends were noted over the timeframe examined. Despite the increases in precipitation, no trends were observed for annual or seasonal discharge at the various sites within the study area. In some locations, nitrate, phosphate, and total nitrogen show downward trends, and total phosphorus and chloride show upward trends.Sanitary sewer overflows (gray infrastructure) and best management practices (green infrastructure) were identified as factors affecting water-quality change. The duration of sanitary sewer overflows was positively correlated with annual loads of nutrients and bacteria, and the drainage area of best management practices was negatively correlated with annual loads of phosphate and sulfate. Results of the study indicate that continued investments in gray and green infrastructure are necessary for urban water-quality improvement. Although this outcome is not unexpected, long-term datasets such as the one used in this study, allow the effects of gray and green infrastructures to be quantified.Results of this study have implications for the Gwynns Falls watershed and its residents and Baltimore City and County managers. Moreover, outcomes are relevant to other watersheds in the metropolitan region that do not have the same long-term dataset. Further, this study has established a framework for ongoing statistical analysis of primary factors affecting urban water-quality trends as regulatory programs mature.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy..tmp..870F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy..tmp..870F"><span>The influence of ENSO, PDO and PNA on secular rainfall variations in Hawai`i</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frazier, Abby G.; Elison Timm, Oliver; Giambelluca, Thomas W.; Diaz, Henry F.</p> <p>2017-11-01</p> <p>Over the last century, significant declines in rainfall across the state of Hawai`i have been observed, and it is unknown whether these declines are due to natural variations in climate, or manifestations of human-induced climate change. Here, a statistical analysis of the observed rainfall variability was applied as first step towards better understanding causes for these long-term trends. Gridded seasonal rainfall from 1920 to 2012 is used to perform an empirical orthogonal function (EOF) analysis. The leading EOF components are correlated with three indices of natural climate variations (El Niño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and Pacific North American (PNA)), and multiple linear regression (MLR) is used to model the leading components with climate indices. PNA is the dominant mode of wet season (November-April) variability, while ENSO is most significant in the dry season (May-October). To assess whether there is an anthropogenic influence on rainfall, two methods are used: a linear trend term is included in the MLR, and pattern correlation coefficients (PCC) are calculated between recent rainfall trends and future changes in rainfall projected by downscaling methods. PCC results indicate that recent observed rainfall trends in the wet season are positively correlated with future expected changes in rainfall, while dry season PCC results do not show a clear pattern. The MLR results, however, show that the trend term adds significantly to model skill only in the dry season. Overall, MLR and PCC results give weak and inconclusive evidence for detection of anthropogenic signals in the observed rainfall trends.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/56198','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/56198"><span>Regional meteorological drivers and long term trends of winter-spring nitrate dynamics across watersheds in northeastern North America</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Jill Crossman; M. Catherine Eimers; Nora J. Casson; Douglas A. Burns; John L. Campbell; Gene E. Likens; Myron J. Mitchell; Sarah J. Nelson; James B. Shanley; Shaun A. Watmough; Kara L. Webster</p> <p>2016-01-01</p> <p>This study evaluated the contribution of winter rain-on-snow (ROS) events to annual and seasonal nitrate (N-NO3) export and identified the regional meteorological drivers of inter-annual variability in ROS N-NO3 export (ROS-N) at 9 headwater streams located across Ontario, Canada and the northeastern United States. Although...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/390163-long-term-trends-metals-pcbs-pesticides-mussels-from-san-francisco-bay','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/390163-long-term-trends-metals-pcbs-pesticides-mussels-from-san-francisco-bay"><span>Long-term trends in metals, PCBs, and pesticides in mussels from San Francisco Bay</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Stephenson, M.D.; Tjeerdema, R.S.; Taberski, K.</p> <p>1995-12-31</p> <p>Many contaminant programs have been established to study the geographical distributions and long-term trends of potential pollutants, but unfortunately, many have been short-lived because of economic cutbacks, providing limited information on long-term trends. The California State Mussel Watch program in conjunction with the San Francisco Estuary Institute (in the last 2 years) have provided continues funding for the past 15 years to mussel watch studies in San Francisco Bay. Long-term trends have been identified that describe declines in many organics and metals during the last 15 years. There are also some metals and organics that show no specific trends. Themore » declines indicate that the banning or restriction of usage of some of these contaminants has resulted in substantial decreases of these substances in the environment.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PrOce..84..242A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PrOce..84..242A"><span>Top-down and bottom-up factors affecting seabird population trends in the California current system (1985-2006)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ainley, David G.; David Hyrenbach, K.</p> <p>2010-03-01</p> <p>To characterize the environmental factors affecting seabird population trends in the central portion of the California current system (CCS), we analyzed standardized vessel-based surveys collected during the late spring (May-June) upwelling season over 22 yr (1985-2006). We tested the working hypothesis that population trends are related to species-specific foraging ecology, and predicted that temporal variation in population size should be most extreme in diving species with higher energy expenditure during foraging. We related variation in individual species abundance (number km -2) to seasonally lagged (late winter, early spring, late spring) and concurrent ocean conditions, and to long-term trends (using a proxy variable: year) during a multi-decadal period of major fluctuations in the El Niño-Southern oscillation (ENSO) and the Pacific decadal oscillation (PDO). We considered both remote (Multivariate ENSO Index, PDO) and local (coastal upwelling indices and sea-surface temperature) environmental variables as proxies for ocean productivity and prey availability. We also related seabird trends to those of potentially major trophic competitors, humpback ( Megaptera novaeangliae) and blue ( Balaenoptera musculus) whales, which increased in number 4-5-fold midway during our study. Cyclical oscillations in seabird abundance were apparent in the black-footed albatross ( Phoebastria nigripes), and decreasing trends were documented for ashy storm-petrel ( Oceanodroma homochroa), pigeon guillemot ( Cepphus columbus), rhinoceros auklet ( Cerorhinca monocerata), Cassin’s auklet ( Ptychoramphus aleuticus), and western gull ( Larus occidentalis); the sooty shearwater ( Puffinus griseus), exhibited a marked decline before signs of recovery at the end of the study period. The abundance of nine other focal species varied with ocean conditions, but without decadal or long-term trends. Six of these species have the largest global populations in the CCS, and four are highly energetic, diving foragers. Furthermore, three of the diving species trends were negatively correlated with the abundance of humpback whales in the study area, a direct competitor for the same prey. Therefore, on the basis of literature reviewed, we hypothesize that the seabirds were affected by the decreasing carrying capacity of the CCS, over-exploitation of some prey stocks and interference competition from the previously exploited, but now increasing, baleen whale populations. Overall, our study highlights the complexity of the ecological factors driving seabird population trends in the highly variable and rapidly changing CCS ecosystem.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoRL..44.7079Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoRL..44.7079Z"><span>Long-term (2005-2014) trends in formaldehyde (HCHO) columns across North America as seen by the OMI satellite instrument: Evidence of changing emissions of volatile organic compounds</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, Lei; Mickley, Loretta J.; Jacob, Daniel J.; Marais, Eloïse A.; Sheng, Jianxiong; Hu, Lu; Abad, Gonzalo González; Chance, Kelly</p> <p>2017-07-01</p> <p>Satellite observations of formaldehyde (HCHO) columns provide top-down information on emissions of highly reactive volatile organic compounds (VOCs). We examine the long-term trends in HCHO columns observed by the Ozone Monitoring Instrument from 2005 to 2014 across North America. Biogenic isoprene is the dominant source of HCHO, and its emission has a large temperature dependence. After correcting for this dependence, we find a general pattern of increases in much of North America but decreases in the southeastern U.S. Over the Houston-Galveston-Brazoria industrial area, HCHO columns decreased by 2.2% a-1 from 2005 to 2014, consistent with trends in emissions of anthropogenic VOCs. Over the Cold Lake Oil Sands in the southern Alberta in Canada, HCHO columns increased by 3.8% a-1, consistent with the increase in crude oil production there. HCHO variability in the northwestern U.S. and Midwest could be related to afforestation and corn silage production. Although NO<fi>x</fi> levels can affect the HCHO yield from isoprene oxidation, we find that decreases in anthropogenic NO<fi>x</fi> emissions made only a small contribution to the observed HCHO trends.<abstract type="synopsis"><title type="main">Plain Language SummaryWe use satellite observations to diagnose long-term trends in HCHO columns across North America from 2005 to 2014. HCHO generally increased from 2005-2009 to 2010-2014 but decreased in the southeastern U.S. We find significant regional trends in excess of 20% related to decreases in urban anthropogenic VOC emissions (Houston metropolitan area) and increases in oil/gas production (oil sands in western Canada). Significant regional trends in the northwestern U.S. and in the Midwest may be driven by afforestation and agricultural activity. The impact of declining NO<fi>x</fi> emission over the U.S. on HCHO columns is likely small over this time frame.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.B31B0462J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.B31B0462J"><span>How consistent are global long-term satellite LAI products in terms of interannual variability and trend?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jiang, C.; Ryu, Y.; Fang, H.</p> <p>2016-12-01</p> <p>Proper usage of global satellite LAI products requires comprehensive evaluation. To address this issue, the Committee on Earth Observation Satellites (CEOS) Land Product Validation (LPV) subgroup proposed a four-stage validation hierarchy. During the past decade, great efforts have been made following this validation framework, mainly focused on absolute magnitude, seasonal trajectory, and spatial pattern of those global satellite LAI products. However, interannual variability and trends of global satellite LAI products have been investigated marginally. Targeting on this gap, we made an intercomparison between seven global satellite LAI datasets, including four short-term ones: MODIS C5, MODIS C6, GEOV1, MERIS, and three long-term products ones: LAI3g, GLASS, and GLOBMAP. We calculated global annual LAI time series for each dataset, among which we found substantial differences. During the overlapped period (2003 - 2011), MODIS C5, GLASS and GLOBMAP have positive correlation (r > 0.6) between each other, while MODIS C6, GEOV1, MERIS, and LAI3g are highly consistent (r > 0.7) in interannual variations. However, the previous three datasets show negative trends, all of which use MODIS C5 reflectance data, whereas the latter four show positive trends, using MODIS C6, SPOT/VGT, ENVISAT/MERIS, and NOAA/AVHRR, respectively. During the pre-MODIS era (1982 - 1999), the three AVHRR-based datasets (LAI3g, GLASS and GLOBMAP) agree well (r > 0.7), yet all of them show oscillation related with NOAA platform changes. In addition, both GLASS and GLOBMAP show clear cut-points around 2000 when they move from AVHRR to MODIS. Such inconsistency is also visible for GEOV1, which uses SPOT-4 and SPOT-5 before and after 2002. We further investigate the map-to-map deviations among these products. This study highlights that continuous sensor calibration and cross calibration are essential to obtain reliable global LAI time series.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMGC23B0629M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMGC23B0629M"><span>Temperature Trends in the White Mountains of New Hampshire</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Murray, G.; Kelsey, E. P.; Raudzens Bailey, A.</p> <p>2014-12-01</p> <p>Located at the summit of Mount Washington (1917 m asl; ~800 hPa), the highest peak in the northeastern United States, the Mount Washington Observatory has meticulously recorded hourly temperature, humidity, cloud-cover, and other atmospheric variables for over 80 years using the same standard procedures to ensure high-quality, homogeneous data. Nearby Hubbard Brook Experimental Forest (253 m asl; ~980 hPa), a Long-Term Ecological Research site, has recorded atmospheric and environmental data since 1956. Together, these two sites provide a unique opportunity to evaluate elevation-dependent climate changes. Using Sen's slope and the Mann Kendall non-parameteric test we examine annual and seasonal trends in minimum, maximum, and mean temperatures. Both Mount Washington and Hubbard Brook exhibit 56-yr warming trends for most seasons, however, the magnitudes and statistical significances are variable, suggesting the processes controlling these trends likely differ with elevation. Since 1957, for instance, spring maximum temperatures at Hubbard Brook have warmed 0.32 °C dec-1 and winter minimums have increased 0.54 °C dec-1, both well within the range reported for six neighboring low elevation stations from 1970-2012 (Wake et al, 2014a,b). In comparison, Mount Washington summit seasonal minimum temperature trends are typically weaker, with changes in winter minimums (the largest of the seasons) reaching only 0.33 °C dec-1. In this presentation, we highlight differences between these two long-term records and discuss possible role of moist processes and boundary layer/free troposphere exposure in causing their divergence. Authors are planning to study the effects of humidity and cloud-cover on summit temperatures and to investigate how changes in the frequency with which the summit is exposed to boundary layer and free tropospheric air masses influences these relationships.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A41C2287C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A41C2287C"><span>Long-term Observations of Intense Precipitation Small-scale Spatial Variability in a Semi-arid Catchment</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cropp, E. L.; Hazenberg, P.; Castro, C. L.; Demaria, E. M.</p> <p>2017-12-01</p> <p>In the southwestern US, the summertime North American Monsoon (NAM) provides about 60% of the region's annual precipitation. Recent research using high-resolution atmospheric model simulations and retrospective predictions has shown that since the 1950's, and more specifically in the last few decades, the mean daily precipitation in the southwestern U.S. during the NAM has followed a decreasing trend. Furthermore, days with more extreme precipitation have intensified. The current work focuses the impact of these long-term changes on the observed small-scale spatial variability of intense precipitation. Since limited long-term high-resolution observational data exist to support such climatological-induced spatial changes in precipitation frequency and intensity, the current work utilizes observations from the USDA-ARS Walnut Gulch Experimental Watershed (WGEW) in southeastern Arizona. Within this 150 km^2 catchment over 90 rain gauges have been installed since the 1950s, measuring at sub-hourly resolution. We have applied geospatial analyses and the kriging interpolation technique to identify long-term changes in the spatial and temporal correlation and anisotropy of intense precipitation. The observed results will be compared with the previously model simulated results, as well as related to large-scale variations in climate patterns, such as the El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160000968','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160000968"><span>Characterization of Nighttime Light Variability Over the Southeastern United States</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cole, Tony A.; Molthan, Andrew L.; Schultz, Lori A.</p> <p>2016-01-01</p> <p>City lights provide indications of human activity at night. Nighttime satellite imagery offers daily snapshots of this activity. With calibrated, science-quality imagery, long-term monitoring can also be achieved. The degree to which city lights fluctuate, however, is not well known. For the application of detecting power outages, this degree of variability is crucial for assessing reductions to city lights based on historical trends. Eight southeastern U.S. cities are analyzed to understand the relationship between emission variability and several population centers. A preliminary, example case power outage study is also discussed as a transition into future work.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5889943','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5889943"><span>Benefits and Pitfalls of GRACE Data Assimilation: a Case Study of Terrestrial Water Storage Depletion in India</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Girotto, Manuela; De Lannoy, Gabriëlle J. M.; Reichle, Rolf H.; Rodell, Matthew; Draper, Clara; Bhanja, Soumendra N.; Mukherjee, Abhijit</p> <p>2018-01-01</p> <p>This study investigates some of the benefits and drawbacks of assimilating Terrestrial Water Storage (TWS) observations from the Gravity Recovery and Climate Experiment (GRACE) into a land surface model over India. GRACE observes TWS depletion associated with anthropogenic groundwater extraction in northwest India. The model, however, does not represent anthropogenic groundwater withdrawals and is not skillful in reproducing the interannual variability of groundwater. Assimilation of GRACE TWS introduces long-term trends and improves the interannual variability in groundwater. But the assimilation also introduces a negative trend in simulated evapotranspiration whereas in reality evapotranspiration is likely enhanced by irrigation, which is also unmodeled. Moreover, in situ measurements of shallow groundwater show no trend, suggesting that the trends are erroneously introduced by the assimilation into the modeled shallow groundwater, when in reality the groundwater is depleted in deeper aquifers. The results emphasize the importance of representing anthropogenic processes in land surface modeling and data assimilation systems. PMID:29643570</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29643570','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29643570"><span>Benefits and Pitfalls of GRACE Data Assimilation: a Case Study of Terrestrial Water Storage Depletion in India.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Girotto, Manuela; De Lannoy, Gabriëlle J M; Reichle, Rolf H; Rodell, Matthew; Draper, Clara; Bhanja, Soumendra N; Mukherjee, Abhijit</p> <p>2017-05-16</p> <p>This study investigates some of the benefits and drawbacks of assimilating Terrestrial Water Storage (TWS) observations from the Gravity Recovery and Climate Experiment (GRACE) into a land surface model over India. GRACE observes TWS depletion associated with anthropogenic groundwater extraction in northwest India. The model, however, does not represent anthropogenic groundwater withdrawals and is not skillful in reproducing the interannual variability of groundwater. Assimilation of GRACE TWS introduces long-term trends and improves the interannual variability in groundwater. But the assimilation also introduces a negative trend in simulated evapotranspiration whereas in reality evapotranspiration is likely enhanced by irrigation, which is also unmodeled. Moreover, in situ measurements of shallow groundwater show no trend, suggesting that the trends are erroneously introduced by the assimilation into the modeled shallow groundwater, when in reality the groundwater is depleted in deeper aquifers. The results emphasize the importance of representing anthropogenic processes in land surface modeling and data assimilation systems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170004673','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170004673"><span>Benefits and Pitfalls of GRACE Data Assimilation: A Case Study of Terrestrial Water Storage Depletion in India</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Girotto, Manuela; De Lannoy, Gabrielle J. M.; Reichle, Rolf H.; Rodell, Matthew; Draper, Clara S.; Bhanja, Soumendra N.; Mukherjee, Abhijit</p> <p>2017-01-01</p> <p>This study investigates some of the benefits and drawbacks of assimilating Terrestrial Water Storage (TWS) observations from the Gravity Recovery and Climate Experiment (GRACE) into a land surface model over India. GRACE observes TWS depletion associated with anthropogenic groundwater extraction in northwest India. The model, however, does not represent anthropogenic groundwater withdrawals and is not skillful in reproducing the interannual variability of groundwater. Assimilation of GRACE TWS introduces long-term trends and improves the interannual variability in groundwater. But the assimilation also introduces a negative trend in simulated evapotranspiration whereas in reality evapotranspiration is likely enhanced by irrigation, which is also unmodeled. Moreover, in situ measurements of shallow groundwater show no trend, suggesting that the trends are erroneously introduced by the assimilation into the modeled shallow groundwater, when in reality the groundwater is depleted in deeper aquifers. The results emphasize the importance of representing anthropogenic processes in land surface modeling and data assimilation systems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMGC21D1130L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMGC21D1130L"><span>Assessing Climate Change Within Lake Champlain</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leibensperger, E. M.; Pierce, W.; Mihuc, T.; Myers, L.</p> <p>2016-12-01</p> <p>Lake Champlain is experiencing environmental stresses that have caused statistically significant biological, chemical, and physical trends. Such trends have already impacted management strategies within the Lake Champlain basin, which lies within the states of New York and Vermont and province of Quebec. A long-term monitoring program initiated in 1992 has revealed warming of upwards of 0.7°C per decade within certain regions of the lake; much faster than observed local atmospheric warming. Here we analyze the observed lake warming in the context of atmospheric variability and assess its uncertainty given monitoring frequency (biweekly to monthly), variable seasonal and hourly observation timing, and synoptic variability of lake dynamics. To address these issues, we use observations from a June-October 2016 deployment of a data buoy on Lake Champlain containing a 1-meter spaced thermistor chain and surface weather station. These new observations, and reanalysis of intensive monitoring during a campaign in 1993, indicate that synoptic variability of lake thermal structure lowers confidence in trends derived from infrequent observations. However, principal component analysis of lake thermal structure reveals two primary modes of variability that are predictable from atmospheric conditions, presenting an opportunity to improve interpretation of existing and future observations.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...49.2931B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...49.2931B"><span>Changes in intense tropical cyclone activity for the western North Pacific during the last decades derived from a regional climate model simulation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barcikowska, Monika; Feser, Frauke; Zhang, Wei; Mei, Wei</p> <p>2017-11-01</p> <p>An atmospheric regional climate model (CCLM) was employed to dynamically downscale atmospheric reanalyses (NCEP/NCAR 1, ERA 40) over the western North Pacific and South East Asia. This approach is used for the first time to reconstruct a tropical cyclone climatology, which extends beyond the satellite era and serves as an alternative data set for inhomogeneous observation-derived records (Best Track Data sets). The simulated TC climatology skillfully reproduces observations of the recent decades (1978-2010), including spatial patterns, frequency, lifetime, trends, variability on interannual and decadal time scales and their association with the large-scale circulation patterns. These skills, facilitated here with the spectral nudging method, seem to be a prerequisite to understand the factors determining spatio-temporal variability of TC activity over the western North Pacific. Long-term trends (1948-2011 and 1959-2001) in both simulations show a strong increase of intense tropical cyclone activity. This contrasts with pronounced multidecadal variations found in observations. The discrepancy may partly originate from temporal inhomogeneities in atmospheric reanalyses and Best Track Data, which affect both the model-based and observational-based trends. An adjustment, which removes the simulated upward trend, reduces the apparent discrepancy. Ultimately, our observational and modeling analysis suggests an important contribution of multi-decadal fluctuations in the TC activity during the last six decades. Nevertheless, due to the uncertainties associated with the inconsistencies and quality changes of those data sets, we call for special caution when reconstructing long-term TC statistics either from atmospheric reanalyses or Best Track Data.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009ems..confE.593Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009ems..confE.593Z"><span>European temperature records of the past five centuries based on documentary information compared to climate simulations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zorita, E.</p> <p>2009-09-01</p> <p>Two European temperature records for the past half-millennium, January-to-April air temperature for Stockholm (Sweden) and seasonal temperature for a Central European region, both derived from the analysis of documentary sources combined with long instrumental records, are compared with the output of forced (solar, volcanic, greenhouse gases) climate simulations with the model ECHO-G. The analysis is complemented with the long (early)-instrumental record of Central England Temperature (CET). Both approaches to study past climates (simulations and reconstructions) are burdened with uncertainties. The main objective of this comparative analysis is to identify robust features and weaknesses that may help to improve models and reconstruction methods. The results indicate a general agreement between simulations and the reconstructed Stockholm and CET records regarding the long-term temperature trend over the recent centuries, suggesting a reasonable choice of the amplitude of the solar forcing in the simulations and sensitivity of the model to the external forcing. However, the Stockholm reconstruction and the CET record also show a long and clear multi-decadal warm episode peaking around 1730, which is absent in the simulations. The uncertainties associated with the reconstruction method or with the simulated internal climate variability cannot easily explain this difference. Regarding the interannual variability, the Stockholm series displays in some periods higher amplitudes than the simulations but these differences are within the statistical uncertainty and further decrease if output from a regional model driven by the global model is used. The long-term trends in the simulations and reconstructions of the Central European temperature agree less well. The reconstructed temperature displays, for all seasons, a smaller difference between the present climate and past centuries than the simulations. Possible reasons for these differences may be related to a limitation of the traditional technique for converting documentary evidence to temperature values to capture long-term climate changes, because the documents often reflect temperatures relative to the contemporary authors' own perception of what constituted 'normal' conditions. By contrast, the simulated and reconstructed inter-annual variability is in rather good agreement.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.H11D1080B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.H11D1080B"><span>Long-term rise of the Water Table in the Northeast US: Climate Variability, Land-Use Change, or Angry Beavers?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Boutt, D. F.</p> <p>2011-12-01</p> <p>The scientific evidence that humans are directly influencing the Earth's natural climate is increasingly compelling. Numerous studies suggest that climate change will lead to changes in the seasonality of surface water availability thereby increasing the need for groundwater development to offset those shortages. Research suggests that the Northeast region of the U.S. is experiencing significant changes to its' natural climate and hydrologic systems. Previous analysis of a long-term regional compilation of the water table response to the last 60 years of climate variability in New England documented a wide range of variability. The investigation evaluated the physical mechanisms, natural variability and response of aquifers in New England using 100 long term groundwater monitoring stations with 20 or more years of data coupled with 67 stream gages, 75 precipitation stations, and 43 temperature stations. Groundwater trends were calculated as normalized anomalies and analyzed with respect to regional compiled precipitation, temperature, and streamflow anomalies to understand the sensitivity of the aquifer systems to change. Interestingly, a trend and regression analysis demonstrate that water level fluctuations are producing statistically significant results with increasing water levels over at least the past thirty years at most (80 out of 100) well sites. In this contribution we investigate the causal mechanisms behind the observed ground water level trends using site-by-site land-use change assessments, cluster analysis, and spatial analysis of beaver populations (a possible proxy for beaver activity). Regionally, average annual precipitation has been slightly increasing since 1900, with 95% of the stations having statistically significant positive trends. Despite this, no correlation is observed between the magnitude of the annual precipitation trends and the magnitude of the groundwater level changes. Land-use change throughout the region has primarily taken place in and around existing urban centers with an overall increase in the percentage of forested land. Individual analysis of well sites in areas with documented land-use change from agriculture and forested land cover to urban land use suggests a positive correlation with increasing water levels. Recently, beaver populations been begun to rise that has led to local increases in wetland areas. These regions also show a high positive correlation to the magnitude of water table rise. Local factors such as land-use change and beaver activity appear to overprint and mask the impact of consistent increases in annual precipitation. Rising water tables have major implications for not only water management but also the agriculture, forestry, fishing, and tourism industries as they all depend on the quantity and quality of water resources of the region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JHyd..542..953K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JHyd..542..953K"><span>Long-term patterns of air temperatures, daily temperature range, precipitation, grass-reference evapotranspiration and aridity index in the USA Great Plains: Part I. Spatial trends</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kukal, M.; Irmak, S.</p> <p>2016-11-01</p> <p>Due to their substantial spatio-temporal behavior, long-term quantification and analyses of important hydrological variables are essential for practical applications in water resources planning, evaluating the water use of agricultural crop production and quantifying crop evapotranspiration patterns and irrigation management vs. hydrologic balance relationships. Observed data at over 800 sites across the Great Plains of USA, comprising of 9 states and 2,307,410 km2 of surface area, which is about 30% of the terrestrial area of the USA, were used to quantify and map large-scale and long-term (1968-2013) spatial trends of air temperatures, daily temperature range (DTR), precipitation, grass-reference evapotranspiration (ETo) and aridity index (AI) at monthly, growing season and annual time steps. Air temperatures had a strong north to south increasing trend, with annual average varying from -1 to 24 °C, and growing season average temperature varying from 8 to 30 °C. DTR gradually decreased from western to eastern parts of the region, with a regional annual and growing season averages of 14.25 °C and 14.79 °C, respectively. Precipitation had a gradual shift towards higher magnitudes from west to east, with the average annual and growing season (May-September) precipitation ranging from 163 to 1486 mm and from 98 to 746 mm, respectively. ETo had a southwest-northeast decreasing trend, with regional annual and growing season averages of 1297 mm and 823 mm, respectively. AI increased from west to east, indicating higher humidity (less arid) towards the east, with regional annual and growing season averages of 0.49 and 0.44, respectively. The spatial datasets and maps for these important climate variables can serve as valuable background for climate change and hydrologic studies in the Great Plains region. Through identification of priority areas from the developed maps, efforts of the concerned personnel and agencies and resources can be diverted towards development of holistic strategies to address water supply and demand challenges under changing climate. These strategies can consist of, but not limited to, advancing water, crop and soil management, and genetic improvements and their relationships with the climatic variables on large scales.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AtmEn.146..195K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AtmEn.146..195K"><span>Long-term response of surface water acid neutralizing capacity in a central Appalachian (USA) river basin to declining acid deposition</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kline, Kathleen M.; Eshleman, Keith N.; Garlitz, James E.; U'Ren, Sarah H.</p> <p>2016-12-01</p> <p>Long-term changes in acid-base chemistry resulting from declining regional acid deposition were examined using data from repeating synoptic surveys conducted within the 275 km2 Upper Savage River Watershed (USRW) in western Maryland (USA); a randomly-selected set of 40 stream reaches was sampled 36 times between 1999 and 2014 to: (1) repeatedly characterize the acid-base status of the entire river basin; (2) determine whether an extensive network of streams of varying order has shown signs of recovery in acid neutralizing capacity (ANC); and (3) understand the key factors controlling the rate of ANC recovery across the river network. Several non-parametric analyses of trends (i.e., Mann Kendall Trend: MKT tests; and Regional Kendall Trend: RKT) in streamwater acid-base chemistry suggest that USRW has significantly responded to declining acid deposition during the study period; the two most robust, statistically significant trends were decreasing surface water SO42- (∼1.5 μeq L-1 yr-1) and NO3- (∼1 μeq L-1 yr-1) concentrations-consistent with observed downward trends in regional wet S and N deposition. Basin-wide decreasing trends in K+, Mg2+, and Ca2+ were also observed, while Na+ concentrations increased. Significant ANC recovery was observed in 10-20% of USRW stream reaches (depending on the p level used), but the magnitude of the trend relative to natural variability was apparently insufficient to allow detection of a basin-wide ANC trend using the RKT test. Watershed factors, such as forest disturbances and increased application of road deicing salts, appeared to contribute to substantial variability in concentrations of NO3- and Na+ in streams across the basin, but these factors did not affect our overall interpretation of the results as a systematic recovery of USRW from regional acidification. Methodologically, RKT appears to be a robust method for identifying basin-wide trends using synoptic data, but MKT results for individual systems should be examined closely (e.g., to identify trends for specific subpopulations).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.G11C0720G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.G11C0720G"><span>Providing long-term trend and gravimetric factor at Chandler period from superconducting gravimeter records by using Singular Spectrum Analysis along with its multivariate extension</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gruszczynska, M.; Rosat, S.; Klos, A.; Bogusz, J.</p> <p>2017-12-01</p> <p>In this study, Singular Spectrum Analysis (SSA) along with its multivariate extension MSSA (Multichannel SSA) were used to estimate long-term trend and gravimetric factor at the Chandler wobble frequency from superconducting gravimeter (SG) records. We have used data from seven stations located worldwide and contributing to the International Geodynamics and Earth Tides Service (IGETS). The timespan ranged from 15 to 19 years. Before applying SSA and MSSA, we had removed local tides, atmospheric (ECMWF data), hydrological (MERRA2 products) loadings and non-tidal ocean loading (ECCO2 products) effects. In the first part of analysis, we used the SSA approach in order to estimate the long-term trends from SG observations. We use the technique based on the classical Karhunen-Loève spectral decomposition of time series into long-term trend, oscillations and noise. In the second part, we present the determination of common time-varying pole tide (annual and Chandler wobble) to estimate gravimetric factor from SG time series using the MSSA approach. The presented method takes advantage over traditional methods like Least Squares Estimation by determining common modes of variability which reflect common geophysical field. We adopted a 6-year lag-window as the optimal length to extract common seasonal signals and the Chandler components of the Earth polar motion. The signals characterized by annual and Chandler wobble account for approximately 62% of the total variance of residual SG data. Then, we estimated the amplitude factors and phase lags of Chandler wobble with respect to the IERS (International Earth Rotation and Reference Systems Service) polar motion observations. The resulting gravimetric factors at the Chandler Wobble period are finally compared with previously estimates. A robust estimate of the gravimetric Earth response to the Chandlerian component of the polar motion is required to better constrain the mantle anelasticity at this frequency and hence the attenuation models of the Earth interior.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2004/3104/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2004/3104/"><span>Trends in Streamflow Characteristics in Hawaii, 1913-2002</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Oki, Delwyn S.</p> <p>2004-01-01</p> <p>The surface-water resources of Hawaii have significant cultural, aesthetic, ecologic, and economic importance. In Hawaii, surface-water resources are developed for both offstream uses (for example, drinking water, agriculture, and industrial uses) and instream uses (for example, maintenance of habitat and ecosystems, recreational activities, aesthetic values, maintenance of water quality, conveyance of irrigation and domestic water supplies, and protection of traditional and customary Hawaiian rights). Possible long-term trends in streamflow characteristics have important implications for water users, water suppliers, resource managers, and citizens in the State. Proper management of Hawaii's streams requires an understanding of long-term trends in streamflow characteristics and their potential implications. Effects of long-term downward trends in low flows in streams include potential loss of habitat for native stream fauna and reduced water availability for offstream and instream water uses. Effects of long-term upward trends in high flows in streams include construction of bridges and water-conveyance structures that are potentially unsafe if they are not designed with proper consideration of trends in high flows.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DSRI..101...54S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DSRI..101...54S"><span>Long-term (1993-2013) changes in macrozooplankton off the Western Antarctic Peninsula</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Steinberg, Deborah K.; Ruck, Kate E.; Gleiber, Miram R.; Garzio, Lori M.; Cope, Joseph S.; Bernard, Kim S.; Stammerjohn, Sharon E.; Schofield, Oscar M. E.; Quetin, Langdon B.; Ross, Robin M.</p> <p>2015-07-01</p> <p>The Western Antarctic Peninsula (WAP) is one of the most rapidly warming regions on Earth, and where a high apex predator biomass is supported in large part by macrozooplankton. We examined trends in summer (January-February) abundance of major taxa of macrozooplankton along the WAP over two decades (1993-2013) and their relationship with environmental parameters (sea ice, atmospheric climate indices, sea surface temperature, and phytoplankton biomass and productivity). Macrozooplankton were collected from the top 120 m of the water column in a mid-Peninsula study region divided into latitudinal (North, South, and Far South) and cross-shelf (coastal, shelf, slope) sub-regions. Trends for krill species included a 5-year cycle in abundance peaks (positive anomalies) for Euphausia superba, but no directional long-term trend, and an increase in Thysanoessa macrura in the North; variability in both species was strongly influenced by primary production 2-years prior. E. crystallorophias abundance was best explained by the Southern Annular Mode (SAM) and Multivariate El Niño Southern Oscillation Index (MEI), and was more abundant in higher ice conditions. The salp Salpa thompsoni and thecosome pteropod Limacina helicina cycled between negative and positive anomalies in the North, but showed increasing positive anomalies in the South over time. Variation in salp and pteropod abundance was best explained by SAM and the MEI, respectively, and both species were more abundant in lower ice conditions. There was a long-term increase in some carnivorous gelatinous zooplankton (polychaete worm Tomopteris spp.) and amphipods. Abundance of Pseudosagitta spp. chaetognaths was closely related to SAM, with higher abundance tied to lower ice conditions. Long-term changes and sub-decadal cycles of WAP macrozooplankton community composition may affect energy transfer to higher trophic levels, and alter biogeochemical cycling in this seasonally productive and sensitive polar ecosystem.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=166182','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=166182"><span>Long-term trends and a sustainability transition</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kates, Robert W.; Parris, Thomas M.</p> <p>2003-01-01</p> <p>How do long-term global trends affect a transition to sustainability? We emphasize the “multitrend” nature of 10 classes of trends, which makes them complex, contradictory, and often poorly understood. Each class includes trends that make a sustainability transition more feasible as well as trends that make it more difficult. Taken in their entirety, they serve as a checklist for the consideration of global trends that impact place-based sustainability studies. PMID:12829798</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Natur.545...41M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Natur.545...41M"><span>Reconciling controversies about the ‘global warming hiatus’</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Medhaug, Iselin; Stolpe, Martin B.; Fischer, Erich M.; Knutti, Reto</p> <p>2017-05-01</p> <p>Between about 1998 and 2012, a time that coincided with political negotiations for preventing climate change, the surface of Earth seemed hardly to warm. This phenomenon, often termed the ‘global warming hiatus’, caused doubt in the public mind about how well anthropogenic climate change and natural variability are understood. Here we show that apparently contradictory conclusions stem from different definitions of ‘hiatus’ and from different datasets. A combination of changes in forcing, uptake of heat by the oceans, natural variability and incomplete observational coverage reconciles models and data. Combined with stronger recent warming trends in newer datasets, we are now more confident than ever that human influence is dominant in long-term warming.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28470193','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28470193"><span>Reconciling controversies about the 'global warming hiatus'.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Medhaug, Iselin; Stolpe, Martin B; Fischer, Erich M; Knutti, Reto</p> <p>2017-05-03</p> <p>Between about 1998 and 2012, a time that coincided with political negotiations for preventing climate change, the surface of Earth seemed hardly to warm. This phenomenon, often termed the 'global warming hiatus', caused doubt in the public mind about how well anthropogenic climate change and natural variability are understood. Here we show that apparently contradictory conclusions stem from different definitions of 'hiatus' and from different datasets. A combination of changes in forcing, uptake of heat by the oceans, natural variability and incomplete observational coverage reconciles models and data. Combined with stronger recent warming trends in newer datasets, we are now more confident than ever that human influence is dominant in long-term warming.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16772324','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16772324"><span>Patterns in food intake correlate with body mass index.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Periwal, Vipul; Chow, Carson C</p> <p>2006-11-01</p> <p>Quantifying eating behavior may give clues to both the physiological and behavioral mechanisms behind weight regulation. We analyzed year-long dietary records of 29 stable-weight subjects. The records showed wide daily variations of food intake. We computed the temporal autocorrelation and skewness of food intake mass, energy, carbohydrate, fat, and protein. We also computed the cross-correlation coefficient between intake mass and intake energy. The mass of the food intake exhibited long-term trends that were positively skewed, with wide variability among individuals. The average duration of the trends (P = 0.003) and the skewness (P = 0.006) of the food intake mass were significantly correlated with mean body mass index (BMI). We also found that the lower the correlation coefficient between the energy content and the mass of food intake, the higher the BMI. Our results imply that humans in neutral energy balance eating ad libitum exhibit a long-term positive bias in the food intake that operates partially through the mass of food eaten to defend against eating too little more vigorously than eating too much.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B41C0056M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B41C0056M"><span>Modeling the Impacts of Long-Term Warming Trends on Gross Primary Productivity Across North America</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mekonnen, Z. A.; Grant, R. F.</p> <p>2014-12-01</p> <p>There is evidence of warming over recent decades in most regions of North America (NA) that affects ecosystem productivity and the past decade has been the warmest since instrumental records of global surface temperatures began. In this study, we examined the spatial and temporal variability and trends of warming across NA using climate data from the North America Regional Reanalysis (NARR) from 1979 to 2010 with a 3-hourly time-step and 0.250 x 0.250 spatial resolution as part of the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP). A comprehensive mathematical process model, ecosys was used to simulate impacts of this variability in warming on gross primary productivity (GPP). In a test of model results, annual GPP modeled for pixels which corresponded to the locations of 25 eddy covariance towers correlated well (R2=0.76) with annual GPP derived from the flux towers in 2005. At the continental scale long-term (2000 - 2010) annual average modeled GPP for NA correlated well (geographically weighed regression R2 = 0.8) with MODIS GPP, demonstrating close similarities in spatial patterns. Results from the NARR indicated that most areas of NA, particularly high latitude regions, have experienced warming but changes in precipitation vary spatially over the last three decades. GPP modeled in most areas with lower mean annual air temperature (Ta), such as those in boreal climate zones, increased due to early spring and late autumn warming observed in NARR. However modeled GPP declined in most southwestern regions of NA, due to water stress from rising Ta and declining precipitation. Overall, GPP modeled across NA had a positive trend of +0.025 P g C yr-1 with a range of -1.16 to 0.87 P g C yr-1 from the long-term mean. Interannual variability of GPP was the greatest in southwest of US and part of the Great Plains, which could be as a result of frequent El Niño-Southern Oscillation' (ENSO) events that led to major droughts.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009GeoRL..3612706Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009GeoRL..3612706Q"><span>On the secular change of spring onset at Stockholm</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qian, Cheng; Fu, Congbin; Wu, Zhaohua; Yan, Zhongwei</p> <p>2009-06-01</p> <p>A newly developed method, the Ensemble Empirical Mode Decomposition, was applied to adaptively determine the timing of climatic spring onset from the daily temperature records at Stockholm during 1756-2000. Secular variations of spring onset and its relationships to the North Atlantic Oscillation (NAO) and to the temperature variability were analyzed. A clear turning point of secular trend in spring onset around 1884/1885, from delaying to advancing, was found. The delaying trend of spring onset (6.9 days/century) during 1757-1884 and the advancing one (-7 days/century) during 1885-1999 were both significant. The winter NAO indices were found to be correlated with the spring onset at Stockholm at an inter-annual timescale only for some decades, but unable to explain the change of the long-term trends. The secular change from cooling to warming around the 1880s, especially in terms of spring temperature, might have led to the secular change of spring onset.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1912337Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1912337Z"><span>Long Term Association of Tropospheric Trace gases over Pakistan by exploiting satellite observations and development of Econometric Regression based Model</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zeb, Naila; Fahim Khokhar, Muhammad; Khan, Saud Ahmed; Noreen, Asma; Murtaza, Rabbia</p> <p>2017-04-01</p> <p>Air pollution is the expected key environmental issue of Pakistan as it is ranked among top polluted countries in the region. Ongoing rapid economic growth without any adequate measures is leading to worst air quality over time. The study aims to monitor long term atmospheric composition and association of trace gases over Pakistan. Tropospheric concentrations of CO, TOC, NO2 and HCHO derived from multiple satellite instruments are used for study from year 2005 to 2014. The study will provide first database for tropospheric trace gases over Pakistan. Spatio-temporal assessment identified hotspots and possible sources of trace gases over the Pakistan. High concentrations of trace gases are mainly observed over Punjab region, which may be attributed to its metropolitan importance. It is the major agricultural, industrialized and urbanized (nearly 60 % of the Pakistan's population) sector of the country. The expected sources are the agricultural fires, biomass/fossil fuel burning for heating purposes, urbanization, industrialization and meteorological variations. Seasonal variability is observed to explore seasonal patterns over the decade. Well defined seasonal cycles of trace gases are observed over the whole study period. The observed seasonal patterns also showed some noteworthy association among trace gases, which is further explored by different statistical tests. Seasonal Mann Kendall test is applied to test the significance of trend in series whereas correlation is carried out to measure the strength of association among trace gases. Strong correlation is observed for trace gases especially between CO and TOC. Partial Mann Kendall test is used to ideally identify the impact of each covariate on long term trend of CO and TOC by partialling out each correlating trace gas (covariate). It is observed that TOC, NO2 and HCHO has significant impact on long term trend of CO whereas, TOC critically depends on NO2 concentrations for long term increase over the region. Furthermore to explore causal relation, regression analysis is employed to estimate model for CO and TOC. This model numerically estimated the long term association of trace gases over the region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4980985','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4980985"><span>Increasing flash droughts over China during the recent global warming hiatus</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Linying; Yuan, Xing; Xie, Zhenghui; Wu, Peili; Li, Yaohui</p> <p>2016-01-01</p> <p>The recent global warming slowdown or hiatus after the big El Niño event in 1997/98 raises the questions of whether terrestrial hydrological cycle is being decelerated and how do the hydrological extremes respond to the hiatus. However, the rapidly developing drought events that are termed as “flash droughts” accompanied by extreme heat, low soil moisture and high evapotranspiration (ET), occurred frequently around the world, and caused devastating impacts on crop yields and water supply. Here, we investigate the long-term trend and variability of flash droughts over China. Flash droughts are most likely to occur over humid and semi-humid regions, such as southern and northeastern China. Flash drought averaged over China increased by 109% from 1979 to 2010, and the increase was mainly due to a long term warming of temperature (50%), followed by the contributions from decreasing soil moisture and increasing ET. There was a slight drop in temperature after 1997, but the increasing trend of flash droughts was tripled. Further results indicate that the decreasing temperature was compensated by the accelerated drying trends of soil moisture and enhanced ET, leading to an acceleration of flash droughts during the warming hiatus. The anthropogenic warming in the next few decades may exacerbate future flash drought conditions in China. PMID:27513724</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.H43I1340J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.H43I1340J"><span>The trend of the multi-scale temporal variability of precipitation in Colorado River Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jiang, P.; Yu, Z.</p> <p>2011-12-01</p> <p>Hydrological problems like estimation of flood and drought frequencies under future climate change are not well addressed as a result of the disability of current climate models to provide reliable prediction (especially for precipitation) shorter than 1 month. In order to assess the possible impacts that multi-scale temporal distribution of precipitation may have on the hydrological processes in Colorado River Basin (CRB), a comparative analysis of multi-scale temporal variability of precipitation as well as the trend of extreme precipitation is conducted in four regions controlled by different climate systems. Multi-scale precipitation variability including within-storm patterns and intra-annual, inter-annual and decadal variabilities will be analyzed to explore the possible trends of storm durations, inter-storm periods, average storm precipitation intensities and extremes under both long-term natural climate variability and human-induced warming. Further more, we will examine the ability of current climate models to simulate the multi-scale temporal variability and extremes of precipitation. On the basis of these analyses, a statistical downscaling method will be developed to disaggregate the future precipitation scenarios which will provide a more reliable and finer temporal scale precipitation time series for hydrological modeling. Analysis results and downscaling results will be presented.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018IzAOP..54..139C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018IzAOP..54..139C"><span>Long-Term Variability of UV Irradiance in the Moscow Region according to Measurement and Modeling Data</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chubarova, N. E.; Pastukhova, A. S.; Galin, V. Ya.; Smyshlyaev, S. P.</p> <p>2018-03-01</p> <p>We have found distinct long-period changes in erythemal UV radiation ( Q er) characterized by a pronounced decrease at the end of the 1970s and a statistically significant positive trend of more than 5%/10 years since 1979 over the territory of the Moscow region according to the measurements and reconstruction model. The positive Q er trend is shown to be associated mainly with a decrease in the effective cloud amount and total ozone content (TOC). Due to these variations, UV resources have significantly changed in spring for the population with the most vulnerable skin type I, which means a transition from the UV optimum to UV moderate excess conditions. The simulation experiments using the INM-RSHU chemistry climate model (CCM) for several scenarios with and without anthropogenic factors have revealed that the variations in the anthropogenic emissions of halogens have the most significant impact on the variability of TOC and Q er. Among natural factors, noticeable effects are observed due to volcanic aerosol. The calculations of the cloud transmittance of Q er are generally consistent with the measurements; however, they do not reproduce the observed value of the positive trend.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1811974M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1811974M"><span>Long-term trends in dissolved iron and DOC concentration linked to nitrate depletion in riparian soils</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Musolff, Andreas; Selle, Benny; Fleckenstein, Jan H.; Oosterwoud, Marieke R.; Tittel, Jörg</p> <p>2016-04-01</p> <p>The instream concentrations of dissolved organic carbon (DOC) are rising in many catchments of the northern hemisphere. Elevated concentrations of DOC, mainly in the form of colored humic components, increase efforts and costs of drinking water purification. In this study, we evaluated a long-term dataset of 110 catchments draining into German drinking water reservoirs in order to assess sources of DOC and drivers of a potential long-term change. The average DOC concentrations across the wide range of different catchments were found to be well explained by the catchment's topographic wetness index. Higher wetness indices were connected to higher average DOC concentrations, which implies that catchments with shallow topography and pronounced riparian wetlands mobilize more DOC. Overall, 37% of the investigated catchments showed a significant long-term increase in DOC concentrations, while 22% exhibited significant negative trends. Moreover, we found that increasing trends in DOC were positively correlated to trends in dissolved iron concentrations at pH≤6 due to remobilization of DOC previously sorbed to iron minerals. Both, increasing trends in DOC and dissolve iron were found to be connected to decreasing trends and low concentrations of nitrate (below ~6 mg/L). This was especially observed in forested catchments where atmospheric N-depositions were the major source for nitrate availability. In these catchments, we also found long-term increases of phosphate concentrations. Therefore, we argue that dissolved iron, DOC and phosphate were jointly released under iron-reducing conditions when nitrate as a competing electron acceptor was too low in concentrations to prevent the microbial iron reduction. In contrast, we could not explain the observed increasing trends in DOC, iron and phosphate concentrations by the long-term trends of pH, sulfate or precipitation. Altogether this study gives strong evidence that both, source and long-term increases in DOC are primarily controlled by riparian wetland soils within the catchments. Here, the achievement of a long-term reduction in nitrogen deposition may in turn lead to a more pronounced iron reduction and a subsequent release of DOC and other iron-bound substances such as phosphate.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AtmRe.196..182B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AtmRe.196..182B"><span>Trends and changes in tropical and summer days at the Adana Sub-Region of the Mediterranean Region, Southern Turkey</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bayer Altın, Türkan; Barak, Belma</p> <p>2017-11-01</p> <p>In this study, the long-term variability and trends of the annual and seasonal numbers of summer and tropical days of the Adana Sub-region were investigated using nonlinear and linear trend detection tests for the period 1960-2014 at 14 meteorological stations. The results suggest that the annual number of summer and tropical days was generally below the long-term average through to the end of the 1980s. In particular, positive anomaly values could be observed at all stations between the years 1993-2014. With respect to the Kruskal-Wallis homogeneity test, the significant breaking date was 1993. The rapid rise of the annual number of summer (tropical) days after this year led to the inversion of the negative trends observed from 1987 to 1992 into positive ones. The increasing trend is statistically significance at 0.01 level in Yumurtalık, Mersin and Antakya for the annual number of summer and tropical days. Dörtyol, İskenderun and Elbistan were significance at 0.01 level for tropical days. The largest positive anomalies of the summer of 2010 are observed in coastal vicinity (Mersin, Yumurtalık and İskenderun). This indicates that these settlements underwent a long-term warm period and thermal conditions due to increasing temperatures in the spring and summer months. The same conditions are found in high inner areas (Göksun and Elbistan) for tropical days. It is noticed that a tendency for greater warming occurred at stations located above 1000 m in the sub-region. The average number of warm days will increase 2-days per 100-years in southern part of the sub-region. The increasing trend in summer temperatures can be considered a potential risk, notably for human health and for economic and crop losses in the Adana Sub-region, including Çukurova, one of the most important agriculture areas of Turkey.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29170490','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29170490"><span>The steady enhancement of the Australian Summer Monsoon in the last 200 years.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gallego, David; García-Herrera, Ricardo; Peña-Ortiz, Cristina; Ribera, Pedro</p> <p>2017-11-23</p> <p>A new bicentennial series of the Australian monsoon strength based on historical wind observations has allowed for the assessment of the variability of this system since the early 19th century. Our series covers a period in which the scarcity of meteorological observations in the area had precluded the evaluation of long-term climatic trends. Results indicate that the increase in precipitation over Northern Australia reported for the last 60 years is just a manifestation of a much longer lasting trend related to the strengthening of the Australian monsoon that has been occurring since at least 1816.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2004/1306/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2004/1306/report.pdf"><span>Quality assurance report - Loch Vale Watershed, 1999-2002</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Botte, Jorin A.; Baron, Jill S.</p> <p>2004-01-01</p> <p>The National Park Service initiated the Loch Vale Watershed (LVWS) project in 1980 with funding from the Aquatic Effects Research Program of the National Acid Precipitation Assessment Program. Long-term ecological research and monitoring address watershed-scale ecosystem processes, particularly as they respond to atmospheric deposition and climate variability. Monitoring of meteorological, hydrologic, precipitation chemistry, and surface water quality parameters enable us to use long-term trends to distinguish natural from human-caused disturbances. Research into snow distribution, hydrologic flowpaths, vegetation responses to N deposition, isotopic transformations of N by forest and soil processes, trace metals, and aquatic ecological responses to disturbance enable us to understand processes that influence high elevation ecosystems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70041333','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70041333"><span>Spatial heterogeneity in statistical power to detect changes in lake area in Alaskan National Wildlife Refuges</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Nicol, Samuel; Roach, Jennifer K.; Griffith, Brad</p> <p>2013-01-01</p> <p>Over the past 50 years, the number and size of high-latitude lakes have decreased throughout many regions; however, individual lake trends have been variable in direction and magnitude. This spatial heterogeneity in lake change makes statistical detection of temporal trends challenging, particularly in small analysis areas where weak trends are difficult to separate from inter- and intra-annual variability. Factors affecting trend detection include inherent variability, trend magnitude, and sample size. In this paper, we investigated how the statistical power to detect average linear trends in lake size of 0.5, 1.0 and 2.0 %/year was affected by the size of the analysis area and the number of years of monitoring in National Wildlife Refuges in Alaska. We estimated power for large (930–4,560 sq km) study areas within refuges and for 2.6, 12.9, and 25.9 sq km cells nested within study areas over temporal extents of 4–50 years. We found that: (1) trends in study areas could be detected within 5–15 years, (2) trends smaller than 2.0 %/year would take >50 years to detect in cells within study areas, and (3) there was substantial spatial variation in the time required to detect change among cells. Power was particularly low in the smallest cells which typically had the fewest lakes. Because small but ecologically meaningful trends may take decades to detect, early establishment of long-term monitoring will enhance power to detect change. Our results have broad applicability and our method is useful for any study involving change detection among variable spatial and temporal extents.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26283032','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26283032"><span>Annual trend patterns of phytoplankton species abundance belie homogeneous taxonomical group responses to climate in the NE Atlantic upwelling.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bode, Antonio; Estévez, M Graciela; Varela, Manuel; Vilar, José A</p> <p>2015-09-01</p> <p>Phytoplankton is a sentinel of marine ecosystem change. Composed by many species with different life-history strategies, it rapidly responds to environment changes. An analysis of the abundance of 54 phytoplankton species in Galicia (NW Spain) between 1989 and 2008 to determine the main components of temporal variability in relation to climate and upwelling showed that most of this variability was stochastic, as seasonality and long term trends contributed to relatively small fractions of the series. In general, trends appeared as non linear, and species clustered in 4 groups according to the trend pattern but there was no defined pattern for diatoms, dinoflagellates or other groups. While, in general, total abundance increased, no clear trend was found for 23 species, 14 species decreased, 4 species increased during the early 1990s, and only 13 species showed a general increase through the series. In contrast, series of local environmental conditions (temperature, stratification, nutrients) and climate-related variables (atmospheric pressure indices, upwelling winds) showed a high fraction of their variability in deterministic seasonality and trends. As a result, each species responded independently to environmental and climate variability, measured by generalized additive models. Most species showed a positive relationship with nutrient concentrations but only a few showed a direct relationship with stratification and upwelling. Climate variables had only measurable effects on some species but no common response emerged. Because its adaptation to frequent disturbances, phytoplankton communities in upwelling ecosystems appear less sensitive to changes in regional climate than other communities characterized by short and well defined productive periods. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23883395','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23883395"><span>Increased river alkalinization in the Eastern U.S.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kaushal, Sujay S; Likens, Gene E; Utz, Ryan M; Pace, Michael L; Grese, Melissa; Yepsen, Metthea</p> <p>2013-09-17</p> <p>The interaction between human activities and watershed geology is accelerating long-term changes in the carbon cycle of rivers. We evaluated changes in bicarbonate alkalinity, a product of chemical weathering, and tested for long-term trends at 97 sites in the eastern United States draining over 260,000 km(2). We observed statistically significant increasing trends in alkalinity at 62 of the 97 sites, while remaining sites exhibited no significant decreasing trends. Over 50% of study sites also had statistically significant increasing trends in concentrations of calcium (another product of chemical weathering) where data were available. River alkalinization rates were significantly related to watershed carbonate lithology, acid deposition, and topography. These three variables explained ~40% of variation in river alkalinization rates. The strongest predictor of river alkalinization rates was carbonate lithology. The most rapid rates of river alkalinization occurred at sites with highest inputs of acid deposition and highest elevation. The rise of alkalinity in many rivers throughout the Eastern U.S. suggests human-accelerated chemical weathering, in addition to previously documented impacts of mining and land use. Increased river alkalinization has major environmental implications including impacts on water hardness and salinization of drinking water, alterations of air-water exchange of CO2, coastal ocean acidification, and the influence of bicarbonate availability on primary production.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoRL..44.4304T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoRL..44.4304T"><span>Intensified dust storm activity and Valley fever infection in the southwestern United States</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tong, Daniel Q.; Wang, Julian X. L.; Gill, Thomas E.; Lei, Hang; Wang, Binyu</p> <p>2017-05-01</p> <p>Climate models have consistently projected a drying trend in the southwestern United States, aiding speculation of increasing dust storms in this region. Long-term climatology is essential to documenting the dust trend and its response to climate variability. We have reconstructed long-term dust climatology in the western United States, based on a comprehensive dust identification method and continuous aerosol observations from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network. We report here direct evidence of rapid intensification of dust storm activity over American deserts in the past decades (1988-2011), in contrast to reported decreasing trends in Asia and Africa. The frequency of windblown dust storms has increased 240% from 1990s to 2000s. This dust trend is associated with large-scale variations of sea surface temperature in the Pacific Ocean, with the strongest correlation with the Pacific Decadal Oscillation. We further investigate the relationship between dust and Valley fever, a fast-rising infectious disease caused by inhaling soil-dwelling fungus (Coccidioides immitis and C. posadasii) in the southwestern United States. The frequency of dust storms is found to be correlated with Valley fever incidences, with a coefficient (r) comparable to or stronger than that with other factors believed to control the disease in two endemic centers (Maricopa and Pima County, Arizona).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JSWSC...7A..21P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JSWSC...7A..21P"><span>Long-term variations of the upper atmosphere parameters on Rome ionosonde observations and their interpretation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Perrone, Loredana; Mikhailov, Andrey; Cesaroni, Claudio; Alfonsi, Lucilla; Santis, Angelo De; Pezzopane, Michael; Scotto, Carlo</p> <p>2017-09-01</p> <p>A recently proposed self-consistent approach to the analysis of thermospheric and ionospheric long-term trends has been applied to Rome ionosonde summer noontime observations for the (1957-2015) period. This approach includes: (i) a method to extract ionospheric parameter long-term variations; (ii) a method to retrieve from observed foF1 neutral composition (O, O2, N2), exospheric temperature, Tex and the total solar EUV flux with λ < 1050 Å; and (iii) a combined analysis of the ionospheric and thermospheric parameter long-term variations using the theory of ionospheric F-layer formation. Atomic oxygen, [O] and [O]/[N2] ratio control foF1 and foF2 while neutral temperature, Tex controls hmF2 long-term variations. Noontime foF2 and foF1 long-term variations demonstrate a negative linear trend estimated over the (1962-2010) period which is mainly due to atomic oxygen decrease after ˜1990. A linear trend in (δhmF2)11y estimated over the (1962-2010) period is very small and insignificant reflecting the absence of any significant trend in neutral temperature. The retrieved neutral gas density, ρ atomic oxygen, [O] and exospheric temperature, Tex long-term variations are controlled by solar and geomagnetic activity, i.e. they have a natural origin. The residual trends estimated over the period of ˜5 solar cycles (1957-2015) are very small (<0.5% per decade) and statistically insignificant.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19120530','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19120530"><span>Current use of the artificial urinary sphincter and its long-term durability: a nationwide survey in Japan.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Arai, Yoichi; Takei, Mineo; Nonomura, Katsuya; Baba, Shiro; Habuchi, Tomonori; Matsuda, Tadashi; Takahashi, Satoru; Igawa, Mikio; Kaiho, Yasuhiro; Nakagawa, Haruo</p> <p>2009-01-01</p> <p>Although the artificial urinary sphincter (AUS) is one of the most effective surgical treatments for severe urinary incontinence, little is known about its use in Japan. A nationwide survey was done to determine contemporary trends in AUS use and its long-term durability. Data on AUS units sold in Japan were provided directly by Takai Hospital Supply Co., Ltd., Tokyo, Japan, and a survey form was sent to all 44 institutes where AUS implantation had been carried out. The survey included various demographic and preoperative variables, surgical variables, and postoperative outcomes. Between 1994 and 2007, a total of 100 AUS devices had been provided in Japan. Of the 44 institutes, 24 responded to the survey, and a total of 64 patients were enrolled in the study. Post-urological surgery incontinence accounted for 81.3% of the indications. During the mean follow-up of 50 months, mechanical failure occurred in four (6.2%), and the device was removed in 13 (20.3%) due to infection (14.0%), erosion (4.7%), or urination difficulty (1.5%). Of the 58 patients evaluated, 91.4% reported social continence. Five- and 10-year failure-free rates were 74.8% and 70.1%, respectively. On multivariate analysis, operative time was an independent predictor of treatment failure (P = 0.0334). Considering recent trends in prostate surgery, the AUS may be significantly underused in Japan. Although excellent long-term durability has been achieved, a learning effect appears to be evident. The Japanese urological community needs to provide appropriate patients with this treatment option.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ThApC.tmp..191N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ThApC.tmp..191N"><span>Unidirectional trends in annual and seasonal climate and extremes in Egypt</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nashwan, Mohamed Salem; Shahid, Shamsuddin; Abd Rahim, Norhan</p> <p>2018-05-01</p> <p>The presence of short- and long-term autocorrelations can lead to considerable change in significance of trend in hydro-climatic time series. Therefore, past findings of climatic trend studies that did not consider autocorrelations became a questionable issue. The spatial patterns in the trends of annual and seasonal temperature, rainfall, and related extremes in Egypt have been assessed in this paper using modified Mann-Kendal (MMK) trend test which can detect unidirectional trends in time series in the presence of short- and long-term autocorrelations. The trends obtained using the MMK test was compared with that obtained using standard Mann-Kendall (MK) test to show how natural variability in climate affects the trends. The daily rainfall and temperature data of Princeton Global Meteorological Forcing for the period 1948-2010 having a spatial resolution of 0.25° × 0.25° was used for this purpose. The results showed a large difference between the trends obtained using MMK and MK tests. The MMK test showed increasing trends in temperature and a number of temperature extremes in Egypt, but almost no change in rainfall and rainfall extremes. The minimum temperature was found to increase (0.08-0.29 °C/decade) much faster compared to maximum temperature (0.07-0.24 °C/decade) and therefore, a decrease in diurnal temperature range (- 0.01 to - 0.16 °C/decade) in most part of Egypt. The number of winter hot days and nights are increasing, while the number of cold days is decreasing in most part of the country. The study provides a more realistic scenario of the changes in climate and weather extremes of Egypt.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/wsp/2358/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wsp/2358/report.pdf"><span>Characteristics and trends of streamflow and dissolved solids in the upper Colorado River Basin, Arizona, Colorado, New Mexico, Utah, and Wyoming</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Liebermann, Timothy D.; Mueller, David K.; Kircher, James E.; Choquette, Anne F.</p> <p>1989-01-01</p> <p>Annual and monthly concentrations and loads of dissolved solids and major constituents were estimated for 70 streamflow-gaging stations in the Upper Colorado River Basin. Trends in streamflow, dissolved-solids concentrations, and dissolved-solids loads were identified. Nonparametric trend-analysis techniques were used to determine step trends resulting from human activities upstream and long-term monotonic trends. Results were compared with physical characteristics of the basin and historical water-resource development in the basin to determine source areas of dissolved solids and possible cause of trends. Mean annual dissolved-solids concentration increases from less than 100 milligrams per liter in the headwater streams to more than 500 milligrams per liter in the outflow from the Upper Colorado River Basin. All the major tributaries that have high concentrations of dissolved solids are downstream from extensive areas of irrigated agriculture. However, irrigation predated the period of record for most sites and was not a factor in many identified trends. Significant annual trends were identified for 30 sites. Most of these trends were related to transbasin exports, changes in land use, salinity-control practices, or reservoir development. The primary factor affecting streamflow and dissolved-solids concentration and load has been the construction of large reservoirs. Reservoirs have decreased the seasonal and annual variability of streamflow and dissolved solids in streams that drain the Gunnison and San Juan River basins. Fontenelle and Flaming Gorge Reservoirs have increased the dissolved-solids load in the Green River because of dissolution of mineral salts from the bank material. The largest trends occurred downstream from Lake Powell. However, the period of record since the completion of filling was too short to estimate the long-term effects of that reservoir.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013NHESS..13..545V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013NHESS..13..545V"><span>Bayesian hierarchical modelling of North Atlantic windiness</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vanem, E.; Breivik, O. N.</p> <p>2013-03-01</p> <p>Extreme weather conditions represent serious natural hazards to ship operations and may be the direct cause or contributing factor to maritime accidents. Such severe environmental conditions can be taken into account in ship design and operational windows can be defined that limits hazardous operations to less extreme conditions. Nevertheless, possible changes in the statistics of extreme weather conditions, possibly due to anthropogenic climate change, represent an additional hazard to ship operations that is less straightforward to account for in a consistent way. Obviously, there are large uncertainties as to how future climate change will affect the extreme weather conditions at sea and there is a need for stochastic models that can describe the variability in both space and time at various scales of the environmental conditions. Previously, Bayesian hierarchical space-time models have been developed to describe the variability and complex dependence structures of significant wave height in space and time. These models were found to perform reasonably well and provided some interesting results, in particular, pertaining to long-term trends in the wave climate. In this paper, a similar framework is applied to oceanic windiness and the spatial and temporal variability of the 10-m wind speed over an area in the North Atlantic ocean is investigated. When the results from the model for North Atlantic windiness is compared to the results for significant wave height over the same area, it is interesting to observe that whereas an increasing trend in significant wave height was identified, no statistically significant long-term trend was estimated in windiness. This may indicate that the increase in significant wave height is not due to an increase in locally generated wind waves, but rather to increased swell. This observation is also consistent with studies that have suggested a poleward shift of the main storm tracks.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA.....4975V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA.....4975V"><span>Local Hydrological effects in Membach, Belgium: influence on the long term gravity variation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van Camp, M.; Dassargues, A.; Vanneste, K.; Verbeeck, K.; Warnant, R.</p> <p>2003-04-01</p> <p>Absolute (AG) and superconducting (SG) gravity measurements have been performed since 1996 at the underground Membach Station (Ardenne, eastern Belgium). Two effects can be distinguished: one seasonal-like and a long-term geophysical trend. The first effect is a 5 µGal seasonal-like term due most probably and mainly to hydrological variations. To determine the thickness of the porous unconsolidated layer covering the fissured bed-rock (low-porosity argillaceous sandstone with quartzitic beds) through which the tunnel was excavated, geophysical prospecting has been undertaken above the Membach station. This shows that the thickness of the weathered zone covering the bedrock can be highly variable between zero and 10 meters (possibly due to palaeo mudflows linked to periglacial conditions in the area). This leads to highly variable (in space) saturation capacity of the subsoil above the gallery. The extensive geological researches will allow us to correct the gravity variations induced by the variable mass of water stored in the shallow partially saturated soil. This work can be essential to correct local effects that can mask regional effects such as changes in continental water storage. Local effects, indeed, could prevent the combination of satellite data (e.g. GRACE) with ground-based gravity measurements. On the other hand, studying the local seasonal variations also contributes to investigate the influence of the water storage variations in small river basins on the time dependent gravity field. The second effect is the detection of a very low geophysical trend in gravity of -0.5+/-0.1 µGal/year. The SG drift, the hydrological effects, and the origin of the low trend are discussed. In particular, we show a good correlation between the gravity measurements and the continuous GPS measurements being made since 1997 at 3 km from the station. Possible crustal deformations could be linked to active faults in the Ardenne and/or bordering the Roer Valley Graben, or perhaps linked to the Eifel plume.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.B44A..03W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.B44A..03W"><span>Characterizing uncertainties in recent trends of global terrestrial net primary production through ensemble modeling</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, W.; Hashimoto, H.; Ganguly, S.; Votava, P.; Nemani, R. R.; Myneni, R. B.</p> <p>2010-12-01</p> <p>Large uncertainties exist in our understanding of the trends and variability in global net primary production (NPP) and its controls. This study attempts to address this question through a multi-model ensemble experiment. In particular, we drive ecosystem models including CASA, LPJ, Biome-BGC, TOPS-BGC, and BEAMS with a long-term climate dataset (i.e., CRU-NCEP) to estimate global NPP from 1901 to 2009 at a spatial resolution of 0.5 x 0.5 degree. We calculate the trends of simulated NPP during different time periods and test their sensitivities to climate variables of solar radiation, air temperature, precipitation, vapor pressure deficit (VPD), and atmospheric CO2 levels. The results indicate a large diversity among the simulated NPP trends over the past 50 years, ranging from nearly no trend to an increasing trend of ~0.1 PgC/yr. Spatial patterns of the NPP generally show positive trends in boreal forests, induced mainly by increasing temperatures in these regions; they also show negative trends in the tropics, although the spatial patterns are more diverse. These diverse trends result from different climatic sensitivities of NPP among the tested models. Depending the ecological processes (e.g., photosynthesis or respiration) a model emphasizes, it can be more or less responsive to changes in solar radiation, temperatures, water, or atmospheric CO2 levels. Overall, these results highlight the limit of current ecosystem models in simulating NPP, which cannot be easily observed. They suggest that the traditional single-model approach is not ideal for characterizing trends and variability in global carbon cycling.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011A%26A...530A..71B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011A%26A...530A..71B"><span>Solar irradiance variability: a six-year comparison between SORCE observations and the SATIRE model</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ball, W. T.; Unruh, Y. C.; Krivova, N. A.; Solanki, S.; Harder, J. W.</p> <p>2011-06-01</p> <p>Aims: We investigate how well modeled solar irradiances agree with measurements from the SORCE satellite, both for total solar irradiance and broken down into spectral regions on timescales of several years. Methods: We use the SATIRE model and compare modeled total solar irradiance (TSI) with TSI measurements over the period 25 February 2003 to 1 November 2009. Spectral solar irradiance over 200-1630 nm is compared with the SIM instrument on SORCE over the period 21 April 2004 to 1 November 2009. We discuss the overall change in flux and the rotational and long-term trends during this period of decline from moderate activity to the recent solar minimum in ~10 nm bands and for three spectral regions of significant interest: the UV integrated over 200-300 nm, the visible over 400-691 nm and the IR between 972-1630 nm. Results: The model captures 97% of the observed TSI variation. This is on the order at which TSI detectors agree with each other during the period considered. In the spectral comparison, rotational variability is well reproduced, especially between 400 and 1200 nm. The magnitude of change in the long-term trends is many times larger in SIM at almost all wavelengths while trends in SIM oppose SATIRE in the visible between 500 and 700 nm and again between 1000 and 1200 nm. We discuss the remaining issues with both SIM data and the identified limits of the model, particularly with the way facular contributions are dealt with, the limit of flux identification in MDI magnetograms during solar minimum and the model atmospheres in the IR employed by SATIRE. However, it is unlikely that improvements in these areas will significantly enhance the agreement in the long-term trends. This disagreement implies that some mechanism other than surface magnetism is causing SSI variations, in particular between 2004 and 2006, if the SIM data are correct. Since SATIRE was able to reproduce UV irradiance between 1991 and 2002 from UARS, either the solar mechanism for SSI variation fundamentally changed around the peak of cycle 23, or there is an inconsistency between UARS and SORCE UV measurements. We favour the second explanation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.3494H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.3494H"><span>High sub-seasonal variability in water volume transports, revealed through a new ocean monitoring initiative using autonomous gliders</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heslop, E.; Ruiz, S.; Allen, J.; Tintoré, J.</p> <p>2012-04-01</p> <p>One of the clear challenges facing oceanography today is to define variability in ocean processes at a seasonal and sub-seasonal scale, in order to clearly identify the signature of both natural large-scale climatic oscillations and the long-term trends brought about by the human-induced change in atmospheric composition. Without visibility of this variance, which helps to determine the margins of significance for long-term trends and decipher cause and effect, the inferences drawn from sparse data points can be misleading. The cyclonic basin scale circulation pattern in the Western Mediterranean has long been known; the role/contribution that processes in the Balearic Basin play in modifying this is less well defined. The Balearic Channels (channels between the Balearic Islands) are constriction points on this basin scale circulation that appear to exert a controlling influence on the north/south exchange of water masses. Understanding the variability in current flows through these channels is important, not just for the transport of heat and salt, but also for ocean biology that responds to physical variability at the scale of that variability. Earlier studies at a seasonal scale identified; an interannual summer/winter variation of 1 Sv in the strength of the main circulation pattern and a high cruise-to-cruise variability in the pattern and strength of the flows through the channels brought about by mesoscale activity. Initial results using new high-resolution data from glider based monitoring missions across the Ibiza Channel (the main exchange channel in the Balearic Basin), combined with ship and contemporaneous satellite data, indicate surprisingly high and rapid changes in the flows of surface and intermediate waters imposed on the broad seasonal cycle. To date the data suggests that there are three potential 'modes' of water volume transport, generated from the interplay between basin and mesoscale circulation. We will review the concept of transport modes as seen through the earlier seasonal ship based studies and demonstrate that the scales of variability captured by the glider monitoring provides a unique view of variability in this circulation system, which is as high on a weekly timescale as the previously identified seasonal cycle.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=60090','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=60090"><span>Long-term changes in Serengeti-Mara wildebeest and land cover: Pastoralism, population, or policies?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Homewood, K.; Lambin, E. F.; Coast, E.; Kariuki, A.; Kikula, I.; Kivelia, J.; Said, M.; Serneels, S.; Thompson, M.</p> <p>2001-01-01</p> <p>Declines in habitat and wildlife in semiarid African savannas are widely reported and commonly attributed to agropastoral population growth, livestock impacts, and subsistence cultivation. However, extreme annual and shorter-term variability of rainfall, primary production, vegetation, and populations of grazers make directional trends and causal chains hard to establish in these ecosystems. Here two decades of changes in land cover and wildebeest in the Serengeti-Mara region of East Africa are analyzed in terms of potential drivers (rainfall, human and livestock population growth, socio-economic trends, land tenure, agricultural policies, and markets). The natural experiment research design controls for confounding variables, and our conceptual model and statistical approach integrate natural and social sciences data. The Kenyan part of the ecosystem shows rapid land-cover change and drastic decline for a wide range of wildlife species, but these changes are absent on the Tanzanian side. Temporal climate trends, human population density and growth rates, uptake of small-holder agriculture, and livestock population trends do not differ between the Kenyan and Tanzanian parts of the ecosystem and cannot account for observed changes. Differences in private versus state/communal land tenure, agricultural policy, and market conditions suggest, and spatial correlations confirm, that the major changes in land cover and dominant grazer species numbers are driven primarily by private landowners responding to market opportunities for mechanized agriculture, less by agropastoral population growth, cattle numbers, or small-holder land use. PMID:11675492</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012GeoRL..39.8502N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012GeoRL..39.8502N"><span>Observations reveal external driver for Arctic sea-ice retreat</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Notz, Dirk; Marotzke, Jochem</p> <p>2012-04-01</p> <p>The very low summer extent of Arctic sea ice that has been observed in recent years is often casually interpreted as an early-warning sign of anthropogenic global warming. For examining the validity of this claim, previously IPCC model simulations have been used. Here, we focus on the available observational record to examine if this record allows us to identify either internal variability, self-acceleration, or a specific external forcing as the main driver for the observed sea-ice retreat. We find that the available observations are sufficient to virtually exclude internal variability and self-acceleration as an explanation for the observed long-term trend, clustering, and magnitude of recent sea-ice minima. Instead, the recent retreat is well described by the superposition of an externally forced linear trend and internal variability. For the externally forced trend, we find a physically plausible strong correlation only with increasing atmospheric CO2 concentration. Our results hence show that the observed evolution of Arctic sea-ice extent is consistent with the claim that virtually certainly the impact of an anthropogenic climate change is observable in Arctic sea ice already today.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29684033','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29684033"><span>Time series smoother for effect detection.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>You, Cheng; Lin, Dennis K J; Young, S Stanley</p> <p>2018-01-01</p> <p>In environmental epidemiology, it is often encountered that multiple time series data with a long-term trend, including seasonality, cannot be fully adjusted by the observed covariates. The long-term trend is difficult to separate from abnormal short-term signals of interest. This paper addresses how to estimate the long-term trend in order to recover short-term signals. Our case study demonstrates that the current spline smoothing methods can result in significant positive and negative cross-correlations from the same dataset, depending on how the smoothing parameters are chosen. To circumvent this dilemma, three classes of time series smoothers are proposed to detrend time series data. These smoothers do not require fine tuning of parameters and can be applied to recover short-term signals. The properties of these smoothers are shown with both a case study using a factorial design and a simulation study using datasets generated from the original dataset. General guidelines are provided on how to discover short-term signals from time series with a long-term trend. The benefit of this research is that a problem is identified and characteristics of possible solutions are determined.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5912770','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5912770"><span>Time series smoother for effect detection</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lin, Dennis K. J.; Young, S. Stanley</p> <p>2018-01-01</p> <p>In environmental epidemiology, it is often encountered that multiple time series data with a long-term trend, including seasonality, cannot be fully adjusted by the observed covariates. The long-term trend is difficult to separate from abnormal short-term signals of interest. This paper addresses how to estimate the long-term trend in order to recover short-term signals. Our case study demonstrates that the current spline smoothing methods can result in significant positive and negative cross-correlations from the same dataset, depending on how the smoothing parameters are chosen. To circumvent this dilemma, three classes of time series smoothers are proposed to detrend time series data. These smoothers do not require fine tuning of parameters and can be applied to recover short-term signals. The properties of these smoothers are shown with both a case study using a factorial design and a simulation study using datasets generated from the original dataset. General guidelines are provided on how to discover short-term signals from time series with a long-term trend. The benefit of this research is that a problem is identified and characteristics of possible solutions are determined. PMID:29684033</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A43D2494L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A43D2494L"><span>Anthropogenic Changes in Mid-latitude Storm and Blocking Activities from Observations and Climate Models</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, D.</p> <p>2017-12-01</p> <p>Fingerprints of anthropogenic climate change can be most readily detected in the high latitudes of Northern Hemisphere, where temperature has been rising faster than the rest of the globe and sea ice cover has shrunk dramatically over recent decades. Reducing the meridional temperature gradient, this amplified warming over the high latitudes influences weather in the middle latitudes by modulating the jet stream, storms, and atmospheric blocking activities. Whether observational records have revealed significant changes in mid-latitude storms and blocking activities, however, has remained a subject of much debate. Buried deep in strong year-to-year variations, the long-term dynamic responses of the atmosphere are more difficult to identify, compared with its thermodynamic responses. Variabilities of decadal and longer timescales further obscure any trends diagnosed from satellite observations, which are often shorter than 40 years. Here, new metrics reflecting storm and blocking activities are developed using surface air temperature and pressure records, and their variations and long-term trends are examined. This approach gives an inkling of the changes in storm and blocking activities since the Industrial Revolution in regions with abundant long-term observational records, e.g. Europe and North America. The relationship between Atlantic Multi-decadal Oscillation and variations in storm and blocking activities across the Atlantic is also scrutinized. The connection between observed centennial trends and anthropogenic forcings is investigated using a hierarchy of numerical tools, from highly idealized to fully coupled atmosphere-ocean models. Pre-industrial control simulations and a set of large ensemble simulations forced by increased CO2 are analyzed to evaluate the range of natural variabilities, which paves the way to singling out significant anthropogenic changes from observational records, as well as predicting future changes in mid-latitude storm and blocking activities in the case of continued anthropogenic CO2 forcing.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18..756L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18..756L"><span>The Uncertainty of Long-term Linear Trend in Global SST Due to Internal Variation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lian, Tao</p> <p>2016-04-01</p> <p>In most parts of the global ocean, the magnitude of the long-term linear trend in sea surface temperature (SST) is much smaller than the amplitude of local multi-scale internal variation. One can thus use the record of a specified period to arbitrarily determine the value and the sign of the long-term linear trend in regional SST, and further leading to controversial conclusions on how global SST responds to global warming in the recent history. Analyzing the linear trend coefficient estimated by the ordinary least-square method indicates that the linear trend consists of two parts: One related to the long-term change, and the other related to the multi-scale internal variation. The sign of the long-term change can be correctly reproduced only when the magnitude of the linear trend coefficient is greater than a theoretical threshold which scales the influence from the multi-scale internal variation. Otherwise, the sign of the linear trend coefficient will depend on the phase of the internal variation, or in the other words, the period being used. An improved least-square method is then proposed to reduce the theoretical threshold. When apply the new method to a global SST reconstruction from 1881 to 2013, we find that in a large part of Pacific, the southern Indian Ocean and North Atlantic, the influence from the multi-scale internal variation on the sign of the linear trend coefficient can-not be excluded. Therefore, the resulting warming or/and cooling linear trends in these regions can-not be fully assigned to global warming.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1512895H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1512895H"><span>Climate driven variability and detectability of temporal trends in low flow indicators for Ireland</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hall, Julia; Murphy, Conor; Harrigan, Shaun</p> <p>2013-04-01</p> <p>Observational data from hydrological monitoring programs plays an important role in informing decision makers of changes in key hydrological variables. To analyse how changes in climate influence stream flow, undisturbed river basins with near-natural conditions limited from human influences are needed. This study analyses low flow indicators derived from observations from the Irish Reference Network. Within the trend analysis approach the influence of individual years or sub-periods on the detected trend are analysed using sequential trend tests on all possible periods (of at least 10 years in length) by varying the start and end dates of records for various indicators. Results from this study highlight that the current standard approach using fixed periods to determine long term trends is not appropriate as statistical significance and direction of trends from short term records do not persist continuously over entire record and can be heavily influenced by extremes within the record. The importance of longer records in contextualising short term trends derived from fixed-periods influenced by natural annual, inter-annual and multi-decadal variability is highlighted. Due to the low signal (trend) to noise (variability) ratio, the apparent trends derived from the low flow indicators cannot be used as confident guides to inform future water resources planning and decision making on climate change. Infact, some derived trends contradict expected climate change impacts and even small changes in study design can change the outcomes to a high degree. Therefore it is important not only to evaluate the magnitude of trends derived from monitoring data but also when a trend of a certain magnitude in a given indicator will be detectable to inform decision making or what changes might be required to detect trends for a certain significance level. In this study, the influence of observed variance in the monitoring records on the expected detection times for trends with a fixed magnitude are presented. Depending on the indicator selected, the sample variance and trend magnitude very different detection time estimates are obtained and in most cases not within the time required for anticipatory adaptation in the water resources sector. Additionally, the minimum changes in low flow indicators required to be detectable are large and changes are unlikely to be statistically detectable for many years. This means that water management and planning for anticipated future climatic changes will be required to take place without these changes being formally statistically detectable.Waiting for these trends to become formally detectable with the traditional statistical methods might not be an option for water resources management. Within the monitoring network, a considerable difference is apparent between stations in terms of detection times and changes required for detection. The existence of flow monitoring stations showing short detection times for specific indicators confirms the potential for identifying stations that may be first responders to climate induced changes. Identifying sentinel stations can increase the ability to more effectively optimise the deployment of resources for monitoring the influences of climatic change in a hydrometric reference network.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007IJBm...51..553R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007IJBm...51..553R"><span>Long-term trends in first arrival and first egg laying dates of some migrant and resident bird species in northern Italy</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rubolini, Diego; Ambrosini, Roberto; Caffi, Mario; Brichetti, Pierandrea; Armiraglio, Stefano; Saino, Nicola</p> <p>2007-08-01</p> <p>Climate change is affecting the phenology of seasonal events in Europe and the Northern Hemisphere, as shown by several studies of birds’ timing of migration and reproduction. Here, we analyse the long-term (1982-2006) trends of first arrival dates of four long-distance migratory birds [swift ( Apus apus), nightingale ( Luscinia megarhynchos), barn swallow ( Hirundo rustica), and house martin ( Delichon urbicum)] and first egg laying dates of two migrant (swift, barn swallow) and two resident species [starling ( Sturnus vulgaris), Italian sparrow ( Passer italiae)] at a study site in northern Italy. We also addressed the effects of local weather (temperature and precipitation) and a climate index (the North Atlantic Oscillation, NAO) on the interannual variability of phenological events. We found that the swift and the barn swallow significantly advanced both arrival and laying dates, whereas all other species did not show any significant temporal trend in either arrival or laying date. The earlier arrival of swifts was explained by increasing local temperatures in April, whereas this was not the case for arrival dates of swallows and first egg laying dates of both species. In addition, arrival dates of house martins were earlier following high NAO winters, while nightingale arrival was earlier when local spring rainfall was greater. Finally, Italian sparrow onset of reproduction was anticipated by greater spring rainfall, but delayed by high spring NAO anomalies, and swift’s onset of reproduction was anticipated by abundant rainfall prior to reproduction. There were no significant temporal trends in the interval between onset of laying and arrival in either the swift or the barn swallow. Our findings therefore indicate that birds may show idiosyncratic responses to climate variability at different spatial scales, though some species may be adjusting their calendar to rapidly changing climatic conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B51E0063K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B51E0063K"><span>Tracking Trends in Fractional Forest Cover Change using Long Term Data from AVHRR and MODIS</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, D. H.; DiMiceli, C.; Sohlberg, R. A.; Hansen, M.; Carroll, M.; Kelly, M.; Townshend, J. R.</p> <p>2014-12-01</p> <p>Tree cover affects terrestrial energy and water exchanges, photosynthesis and transpiration, net primary production, and carbon and nutrient fluxes. Accurate and long-term continuous observation of tree cover change is critical for the study of the gradual ecosystem change. Tree cover is most commonly inferred from categorical maps which may inadequately represent within-class heterogeneity for many analyses. Alternatively, Vegetation Continuous Fields data measures fractions or proportions of pixel area. Recent development in remote sensing data processing and cross sensor calibration techniques enabled the continuous, long-term observations such as Land Long-Term Data Records. Such data products and their surface reflectance data have enhanced the possibilities for long term Vegetation Continuous Fields data, thus enabling the estimation of long term trend of fractional forest cover change. In this presentation, we will summarize the progress in algorithm development including automation of training selection for deciduous and evergreen forest, the preliminary results, and its future applications to relate trends in fractional forest cover change and environmental change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4763154','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4763154"><span>Time Series Modelling of Syphilis Incidence in China from 2005 to 2012</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhang, Xingyu; Zhang, Tao; Pei, Jiao; Liu, Yuanyuan; Li, Xiaosong; Medrano-Gracia, Pau</p> <p>2016-01-01</p> <p>Background The infection rate of syphilis in China has increased dramatically in recent decades, becoming a serious public health concern. Early prediction of syphilis is therefore of great importance for heath planning and management. Methods In this paper, we analyzed surveillance time series data for primary, secondary, tertiary, congenital and latent syphilis in mainland China from 2005 to 2012. Seasonality and long-term trend were explored with decomposition methods. Autoregressive integrated moving average (ARIMA) was used to fit a univariate time series model of syphilis incidence. A separate multi-variable time series for each syphilis type was also tested using an autoregressive integrated moving average model with exogenous variables (ARIMAX). Results The syphilis incidence rates have increased three-fold from 2005 to 2012. All syphilis time series showed strong seasonality and increasing long-term trend. Both ARIMA and ARIMAX models fitted and estimated syphilis incidence well. All univariate time series showed highest goodness-of-fit results with the ARIMA(0,0,1)×(0,1,1) model. Conclusion Time series analysis was an effective tool for modelling the historical and future incidence of syphilis in China. The ARIMAX model showed superior performance than the ARIMA model for the modelling of syphilis incidence. Time series correlations existed between the models for primary, secondary, tertiary, congenital and latent syphilis. PMID:26901682</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26901682','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26901682"><span>Time Series Modelling of Syphilis Incidence in China from 2005 to 2012.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Xingyu; Zhang, Tao; Pei, Jiao; Liu, Yuanyuan; Li, Xiaosong; Medrano-Gracia, Pau</p> <p>2016-01-01</p> <p>The infection rate of syphilis in China has increased dramatically in recent decades, becoming a serious public health concern. Early prediction of syphilis is therefore of great importance for heath planning and management. In this paper, we analyzed surveillance time series data for primary, secondary, tertiary, congenital and latent syphilis in mainland China from 2005 to 2012. Seasonality and long-term trend were explored with decomposition methods. Autoregressive integrated moving average (ARIMA) was used to fit a univariate time series model of syphilis incidence. A separate multi-variable time series for each syphilis type was also tested using an autoregressive integrated moving average model with exogenous variables (ARIMAX). The syphilis incidence rates have increased three-fold from 2005 to 2012. All syphilis time series showed strong seasonality and increasing long-term trend. Both ARIMA and ARIMAX models fitted and estimated syphilis incidence well. All univariate time series showed highest goodness-of-fit results with the ARIMA(0,0,1)×(0,1,1) model. Time series analysis was an effective tool for modelling the historical and future incidence of syphilis in China. The ARIMAX model showed superior performance than the ARIMA model for the modelling of syphilis incidence. Time series correlations existed between the models for primary, secondary, tertiary, congenital and latent syphilis.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSPO54C3262F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSPO54C3262F"><span>Is the Oceanography of the New Zealand Subantarctic Region Responding to the Tropics?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Forcen-Vazquez, A. N.</p> <p>2016-02-01</p> <p>The Campbell Plateau, south of New Zealand plays an important role in New Zealand's regional climate and its oceanography may have a significant impact on fluctuations in fish stocks and marine mammal populations. It is located between the Subtropical and Subantarctic Fronts and exhibits marked variability over long time scales. It has been previously assumed, because of its location, that the Campbell Plateau oceanography is driven by Subantarctic and polar processes. Recent analysis, presented here, suggests this in not the case, and instead forcing comes from the tropics and subtropics. This is supported by positive correlations of Sea Level Anomalies (SLA) and Sea Surface Temperature (SST) with the Southern Oscillation Index (SOI) with SOI leading changes on the Campbell Plateau by two months for SLA and seven months for SST. Here we will present evidence of the similarity between the Campbell Plateau and the Tasman Sea SLA trends which suggests a closer relationship with the subtropical region. Satellite collected SLA data and SST from the last two decades are investigated to understand trends and long-term variability over the Campbell Plateau and its relationship with the surrounding open ocean, and other potential remote drivers of variability.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2013/1061/support/ofr2013-1061.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2013/1061/support/ofr2013-1061.pdf"><span>Groundwater-level trends and forecasts, and salinity trends, in the Azraq, Dead Sea, Hammad, Jordan Side Valleys, Yarmouk, and Zarqa groundwater basins, Jordan</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Goode, Daniel J.; Senior, Lisa A.; Subah, Ali; Jaber, Ayman</p> <p>2013-01-01</p> <p>Changes in groundwater levels and salinity in six groundwater basins in Jordan were characterized by using linear trends fit to well-monitoring data collected from 1960 to early 2011. On the basis of data for 117 wells, groundwater levels in the six basins were declining, on average about -1 meter per year (m/yr), in 2010. The highest average rate of decline, -1.9 m/yr, occurred in the Jordan Side Valleys basin, and on average no decline occurred in the Hammad basin. The highest rate of decline for an individual well was -9 m/yr. Aquifer saturated thickness, a measure of water storage, was forecast for year 2030 by using linear extrapolation of the groundwater-level trend in 2010. From 30 to 40 percent of the saturated thickness, on average, was forecast to be depleted by 2030. Five percent of the wells evaluated were forecast to have zero saturated thickness by 2030. Electrical conductivity was used as a surrogate for salinity (total dissolved solids). Salinity trends in groundwater were much more variable and less linear than groundwater-level trends. The long-term linear salinity trend at most of the 205 wells evaluated was not increasing, although salinity trends are increasing in some areas. The salinity in about 58 percent of the wells in the Amman-Zarqa basin was substantially increasing, and the salinity in Hammad basin showed a long-term increasing trend. Salinity increases were not always observed in areas with groundwater-level declines. The highest rates of salinity increase were observed in regional discharge areas near groundwater pumping centers.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMOS43B..01K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMOS43B..01K"><span>Unabated global surface temperature warming: evaluating the evidence</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karl, T. R.; Arguez, A.</p> <p>2015-12-01</p> <p>New insights related to time-dependent bias corrections in global surface temperatures have led to higher rates of warming over the past few decades than previously reported in the IPCC Fifth Assessment Report (2014). Record high global temperatures in the past few years have also contributed to larger trends. The combination of these factors and new analyses of the rate of temperature change show unabated global warming since at least the mid-Twentieth Century. New time-dependent bias corrections account for: (1) differences in temperatures measured from ships and drifting buoys; (2) improved corrections to ship measured temperatures; and (3) the larger rates of warming in polar regions (particularly the Arctic). Since 1951, the period over which IPCC (2014) attributes over half of the observed global warming to human causes, it is shown that there has been a remarkably robust and sustained warming, punctuated with inter-annual and decadal variability. This finding is confirmed through simple trend analysis and Empirical Mode Decomposition (EMD). Trend analysis however, especially for decadal trends, is sensitive to selection bias of beginning and ending dates. EMD has no selection bias. Additionally, it can highlight both short- and long-term processes affecting the global temperature times series since it addresses both non-linear and non-stationary processes. For the new NOAA global temperature data set, our analyses do not support the notion of a hiatus or slowing of long-term global warming. However, sub-decadal periods of little (or no warming) and rapid warming can also be found, clearly showing the impact of inter-annual and decadal variability that previously has been attributed to both natural and human-induced non-greenhouse forcings.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Icar..295....1V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Icar..295....1V"><span>Sulfur dioxide in the Venus Atmosphere: II. Spatial and temporal variability</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vandaele, A. C.; Korablev, O.; Belyaev, D.; Chamberlain, S.; Evdokimova, D.; Encrenaz, Th.; Esposito, L.; Jessup, K. L.; Lefèvre, F.; Limaye, S.; Mahieux, A.; Marcq, E.; Mills, F. P.; Montmessin, F.; Parkinson, C. D.; Robert, S.; Roman, T.; Sandor, B.; Stolzenbach, A.; Wilson, C.; Wilquet, V.</p> <p>2017-10-01</p> <p>The vertical distribution of sulfur species in the Venus atmosphere has been investigated and discussed in Part I of this series of papers dealing with the variability of SO2 on Venus. In this second part, we focus our attention on the spatial (horizontal) and temporal variability exhibited by SO2. Appropriate data sets - SPICAV/UV nadir observations from Venus Express, ground-based ALMA and TEXES, as well as UV observation on the Hubble Space Telescope - have been considered for this analysis. High variability both on short-term and short-scale are observed. The long-term trend observed by these instruments shows a succession of rapid increases followed by slow decreases in the SO2 abundance at the cloud top level, implying that the transport of air from lower altitudes plays an important role. The origins of the larger amplitude short-scale, short-term variability observed at the cloud tops are not yet known but are likely also connected to variations in vertical transport of SO2 and possibly to variations in the abundance and production and loss of H2O, H2SO4, and Sx.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28428539','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28428539"><span>Separating decadal global water cycle variability from sea level rise.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hamlington, B D; Reager, J T; Lo, M-H; Karnauskas, K B; Leben, R R</p> <p>2017-04-20</p> <p>Under a warming climate, amplification of the water cycle and changes in precipitation patterns over land are expected to occur, subsequently impacting the terrestrial water balance. On global scales, such changes in terrestrial water storage (TWS) will be reflected in the water contained in the ocean and can manifest as global sea level variations. Naturally occurring climate-driven TWS variability can temporarily obscure the long-term trend in sea level rise, in addition to modulating the impacts of sea level rise through natural periodic undulation in regional and global sea level. The internal variability of the global water cycle, therefore, confounds both the detection and attribution of sea level rise. Here, we use a suite of observations to quantify and map the contribution of TWS variability to sea level variability on decadal timescales. In particular, we find that decadal sea level variability centered in the Pacific Ocean is closely tied to low frequency variability of TWS in key areas across the globe. The unambiguous identification and clean separation of this component of variability is the missing step in uncovering the anthropogenic trend in sea level and understanding the potential for low-frequency modulation of future TWS impacts including flooding and drought.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25806946','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25806946"><span>Long tree-ring chronologies provide evidence of recent tree growth decrease in a Central African tropical forest.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Battipaglia, Giovanna; Zalloni, Enrica; Castaldi, Simona; Marzaioli, Fabio; Cazzolla-Gatti, Roberto; Lasserre, Bruno; Tognetti, Roberto; Marchetti, Marco; Valentini, Riccardo</p> <p>2015-01-01</p> <p>It is still unclear whether the exponential rise of atmospheric CO2 concentration has produced a fertilization effect on tropical forests, thus incrementing their growth rate, in the last two centuries. As many factors affect tree growth patterns, short -term studies might be influenced by the confounding effect of several interacting environmental variables on plant growth. Long-term analyses of tree growth can elucidate long-term trends of plant growth response to dominant drivers. The study of annual rings, applied to long tree-ring chronologies in tropical forest trees enables such analysis. Long-term tree-ring chronologies of three widespread African species were measured in Central Africa to analyze the growth of trees over the last two centuries. Growth trends were correlated to changes in global atmospheric CO2 concentration and local variations in the main climatic drivers, temperature and rainfall. Our results provided no evidence for a fertilization effect of CO2 on tree growth. On the contrary, an overall growth decline was observed for all three species in the last century, which appears to be significantly correlated to the increase in local temperature. These findings provide additional support to the global observations of a slowing down of C sequestration in the trunks of forest trees in recent decades. Data indicate that the CO2 increase alone has not been sufficient to obtain a tree growth increase in tropical trees. The effect of other changing environmental factors, like temperature, may have overridden the fertilization effect of CO2.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015HESSD..12.5219M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015HESSD..12.5219M"><span>Long-term effects of climate and land cover change on freshwater provision in the tropical Andes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Molina, A.; Vanacker, V.; Brisson, E.; Mora, D.; Balthazar, V.</p> <p>2015-06-01</p> <p>Andean headwater catchments play a pivotal role to supply fresh water for downstream water users. However, few long-term studies exist on the relative importance of climate change and direct anthropogenic perturbations on flow regimes. In this paper, we assess multi-decadal change in freshwater provision based on long time series (1974-2008) of hydrometeorological data and land cover reconstructions for a 282 km2 catchment located in the tropical Andes. Three main land cover change trajectories can be distinguished: (1) rapid decline of native vegetation in montane forest and páramo ecosystems in ~1/5 or 20% of the catchment area, (2) expansion of agricultural land by 14% of the catchment area, (3) afforestation of 12% of native páramo grasslands with exotic tree species in recent years. Given the strong temporal variability of precipitation and streamflow data related to El Niño-Southern Oscillation, we use empirical mode decomposition techniques to detrend the time series. The long-term increasing trend in rainfall is remarkably different from the observed changes in streamflow that exhibit a decreasing trend. Hence, observed changes in streamflow are not the result of long-term climate change but very likely result from direct anthropogenic disturbances after land cover change. Partial water budgets for montane cloud forest and páramo ecosystems suggest that the strongest changes in evaporative water losses are observed in páramo ecosystems, where progressive colonization and afforestation of high alpine grasslands leads to a strong increase in transpiration losses.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4373839','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4373839"><span>Long Tree-Ring Chronologies Provide Evidence of Recent Tree Growth Decrease in a Central African Tropical Forest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Battipaglia, Giovanna; Zalloni, Enrica; Castaldi, Simona; Marzaioli, Fabio; Cazzolla- Gatti, Roberto; Lasserre, Bruno; Tognetti, Roberto; Marchetti, Marco; Valentini, Riccardo</p> <p>2015-01-01</p> <p>It is still unclear whether the exponential rise of atmospheric CO2 concentration has produced a fertilization effect on tropical forests, thus incrementing their growth rate, in the last two centuries. As many factors affect tree growth patterns, short -term studies might be influenced by the confounding effect of several interacting environmental variables on plant growth. Long-term analyses of tree growth can elucidate long-term trends of plant growth response to dominant drivers. The study of annual rings, applied to long tree-ring chronologies in tropical forest trees enables such analysis. Long-term tree-ring chronologies of three widespread African species were measured in Central Africa to analyze the growth of trees over the last two centuries. Growth trends were correlated to changes in global atmospheric CO2 concentration and local variations in the main climatic drivers, temperature and rainfall. Our results provided no evidence for a fertilization effect of CO2 on tree growth. On the contrary, an overall growth decline was observed for all three species in the last century, which appears to be significantly correlated to the increase in local temperature. These findings provide additional support to the global observations of a slowing down of C sequestration in the trunks of forest trees in recent decades. Data indicate that the CO2 increase alone has not been sufficient to obtain a tree growth increase in tropical trees. The effect of other changing environmental factors, like temperature, may have overridden the fertilization effect of CO2. PMID:25806946</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.6765M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.6765M"><span>Long-term variability of the thunderstorm and hail potential in Europe</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mohr, Susanna; Kunz, Michael; Speidel, Johannes; Piper, David</p> <p>2016-04-01</p> <p>Severe thunderstorms and associated hazardous weather events such as hail frequently cause considerable damage to buildings, crops, and automobiles, resulting in large monetary costs in many parts of Europe and the world. To relate single extreme hail events to the historic context and to estimate their return periods and possible trends related to climate change, long-term statistics of hail events are required. Due to the local-scale nature of hail and a lack of suitable observation systems, however, hailstorms are not captured reliably and comprehensively for a long period of time. In view of this fact, different proxies (indirect climate data) obtained from sounding stations and regional climate models can be used to infer the probability and intensity of thunderstorms or hailstorms. In contrast to direct observational data, such proxies are available homogeneously over a long time period. The aim of the study is to investigate the potential for severe thunderstorms and their changes over past decades. Statistical analyses of sounding data show that the convective potential over the past 20 - 30 years has significantly increased over large parts of Central Europe, making severe thunderstorms more likely. A similar picture results from analyses of weather types that are most likely associated with damaging hailstorms. These weather patterns have increased, even if only slightly but nevertheless statistically significantly, in the time period from 1971 to 2000. To improve the diagnostics of hail events in regional climate models, a logistic hail model has been developed by means of a multivariate analysis method. The model is based on a combination of appropriate hail-relevant meteorological parameters. The output of the model is a new index that estimates the potential of the atmosphere for hailstorm development, referred to as potential hail index (PHI). Applied to a high-resolved reanalysis run for Europe driven by NCEP/NCAR1, long-term changes of the PHI for 60 years (1951-2010) show large annual and multiannual variability. The trends are mostly positive in the western parts and negative to the east. However, due to the large temporal variability, the trends are not significant at most of the grid points. Furthermore, it becomes clear that the environmental conditions that favor the formation of hailstorms prevail in larger areas. This finding suggests that, despite the local-scale nature of convective storms, the ambient conditions favoring these events are mainly controlled by large-scale circulation patterns and mechanisms. This result is important to estimate the convective potential of the atmosphere in case of single events.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhyA..437..130L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhyA..437..130L"><span>Long memory in international financial markets trends and short movements during 2008 financial crisis based on variational mode decomposition and detrended fluctuation analysis</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lahmiri, Salim</p> <p>2015-11-01</p> <p>The purpose of this study is to investigate long-range dependence in trend and short variation of stock market price and return series before, during, and after 2008 financial crisis. Variational mode decomposition (VMD), a newly introduced technique for signal processing, is adopted to decompose stock market data into a finite set of modes so as to obtain long term trends and short term movements of stock market data. Then, the detrended fluctuation analysis (DFA) and range scale (R/S) analysis are used to estimate Hurst exponent in each variational mode obtained from VMD. For both price and return series, the empirical results from twelve international stock markets show evidence that long term trends are persistent, whilst short term variations are anti-persistent before, during, and after 2008 financial crisis.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA398458','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA398458"><span>The DOD Humanitarian and Civic Assistance Program Concepts, Trends, Medical Challenges</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1997-03-01</p> <p>program improvements; measuring program performance and effectiveness; and defining military roles relevant to training, long term benefits, and the...support conclusions relevant to trends, benefits, challenges, suggested improvements, and suggested areas for future research. 15. SUBJECT TERMS 16...a Long Term Medical Benefit ................ 28 CONCLUSION</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1412881','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1412881"><span>Basin-scale heterogeneity in Antarctic precipitation and its impact on surface mass variability</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Fyke, Jeremy; Lenaerts, Jan T. M.; Wang, Hailong</p> <p></p> <p>Annually averaged precipitation in the form of snow, the dominant term of the Antarctic Ice Sheet surface mass balance, displays large spatial and temporal variability. Here we present an analysis of spatial patterns of regional Antarctic precipitation variability and their impact on integrated Antarctic surface mass balance variability simulated as part of a preindustrial 1800-year global, fully coupled Community Earth System Model simulation. Correlation and composite analyses based on this output allow for a robust exploration of Antarctic precipitation variability. We identify statistically significant relationships between precipitation patterns across Antarctica that are corroborated by climate reanalyses, regional modeling and icemore » core records. These patterns are driven by variability in large-scale atmospheric moisture transport, which itself is characterized by decadal- to centennial-scale oscillations around the long-term mean. We suggest that this heterogeneity in Antarctic precipitation variability has a dampening effect on overall Antarctic surface mass balance variability, with implications for regulation of Antarctic-sourced sea level variability, detection of an emergent anthropogenic signal in Antarctic mass trends and identification of Antarctic mass loss accelerations.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1412881-basin-scale-heterogeneity-antarctic-precipitation-its-impact-surface-mass-variability','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1412881-basin-scale-heterogeneity-antarctic-precipitation-its-impact-surface-mass-variability"><span>Basin-scale heterogeneity in Antarctic precipitation and its impact on surface mass variability</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Fyke, Jeremy; Lenaerts, Jan T. M.; Wang, Hailong</p> <p>2017-11-15</p> <p>Annually averaged precipitation in the form of snow, the dominant term of the Antarctic Ice Sheet surface mass balance, displays large spatial and temporal variability. Here we present an analysis of spatial patterns of regional Antarctic precipitation variability and their impact on integrated Antarctic surface mass balance variability simulated as part of a preindustrial 1800-year global, fully coupled Community Earth System Model simulation. Correlation and composite analyses based on this output allow for a robust exploration of Antarctic precipitation variability. We identify statistically significant relationships between precipitation patterns across Antarctica that are corroborated by climate reanalyses, regional modeling and icemore » core records. These patterns are driven by variability in large-scale atmospheric moisture transport, which itself is characterized by decadal- to centennial-scale oscillations around the long-term mean. We suggest that this heterogeneity in Antarctic precipitation variability has a dampening effect on overall Antarctic surface mass balance variability, with implications for regulation of Antarctic-sourced sea level variability, detection of an emergent anthropogenic signal in Antarctic mass trends and identification of Antarctic mass loss accelerations.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.4843S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.4843S"><span>The end of trend-estimation for extreme floods under climate change?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schulz, Karsten; Bernhardt, Matthias</p> <p>2016-04-01</p> <p>An increased risk of flood events is one of the major threats under future climate change conditions. Therefore, many recent studies have investigated trends in flood extreme occurences using historic long-term river discharge data as well as simulations from combined global/regional climate and hydrological models. Severe floods are relatively rare events and the robust estimation of their probability of occurrence requires long time series of data (6). Following a method outlined by the IPCC research community, trends in extreme floods are calculated based on the difference of discharge values exceeding e.g. a 100-year level (Q100) between two 30-year windows, which represents prevailing conditions in a reference and a future time period, respectively. Following this approach, we analysed multiple, synthetically derived 2,000-year trend-free, yearly maximum runoff data generated using three different extreme value distributions (EDV). The parameters were estimated from long term runoff data of four large European watersheds (Danube, Elbe, Rhine, Thames). Both, Q100-values estimated from 30-year moving windows, as well as the subsequently derived trends showed enormous variations with time: for example, estimating the Extreme Value (Gumbel) - distribution for the Danube data, trends of Q100 in the synthetic time-series range from -4,480 to 4,028 m³/s per 100 years (Q100 =10,071m³/s, for reference). Similar results were found when applying other extreme value distributions (Weibull, and log-Normal) to all of the watersheds considered. This variability or "background noise" of estimating trends in flood extremes makes it almost impossible to significantly distinguish any real trend in observed as well as modelled data when such an approach is applied. These uncertainties, even though known in principle are hardly addressed and discussed by the climate change impact community. Any decision making and flood risk management, including the dimensioning of flood protection measures, that is based on such studies might therefore be fundamentally flawed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/15849','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/15849"><span>Climate-tree growth models in relation to long-term growth trends of white oak in Pennsylvania</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>D. D. Davis; R. P. Long</p> <p>2003-01-01</p> <p>We examined long-term growth trends of white oak by comparing tree-ring chronologies developed from an old-growth stand, where the average tree age was 222 years, with a second-growth stand where average tree age was 78 years. Evaluation of basal area growth trends suggested that an anomalous decrease in basal area increment trend occurred in both stands during the...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AdSpR..39..197S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AdSpR..39..197S"><span>Long-term dynamics of chlorophyll concentration in the ocean surface layer (by space data)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shevyrnogov, A.; Vysotskaya, G.</p> <p></p> <p>To preserve the biosphere and to use it efficiently, it is necessary to gain a deep insight into the dynamics of the primary production process on our planet. Variability of chlorophyll concentration in the ocean is one of the most important components of this process. These investigations are, however, very labor-consuming, because of the difficulties related to the accessibility of the water surface and its large size. In this work long-term changes in chlorophyll concentration in the surface layer of the ocean have been analyzed on the basis of the CZCS data for 7.5 years from 1979 to 1986 and the SeaWiFS data from 1997 to 2004. It has been shown that the average chlorophyll concentration calculated in all investigated areas varies moderately. However, when analyzing spatially local trends, the areas have been detected that have significant rise and fall of chlorophyll concentrations. Some interesting features of the long-term dynamics of chlorophyll concentration have been found. The opposite directions of long-term trends (essential increase or decrease) cannot be explained only by large-scale hydrological phenomena in the ocean (currents, upwellings, etc.). The measured chlorophyll concentration results from the balance between production and destruction processes. Which process dominates is determined by various hydrophysical, hydrobiological, and climatic processes, leading to sharp rises or falls of the concentration. It is important to estimate the scale of the areas in which this or that process dominates. Therefore, the study addresses not only the dynamics of the mean value but also the dynamics of the areas in which the dominance of certain factors has led to a sharp fall or rise in chlorophyll concentration. Thus, the obtained results can be used to estimate long-term changes in the ocean biota.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JHyd..557..726K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JHyd..557..726K"><span>Identification of relationships between climate indices and long-term precipitation in South Korea using ensemble empirical mode decomposition</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Taereem; Shin, Ju-Young; Kim, Sunghun; Heo, Jun-Haeng</p> <p>2018-02-01</p> <p>Climate indices characterize climate systems and may identify important indicators for long-term precipitation, which are driven by climate interactions in atmosphere-ocean circulation. In this study, we investigated the climate indices that are effective indicators of long-term precipitation in South Korea, and examined their relationships based on statistical methods. Monthly total precipitation was collected from a total of 60 meteorological stations, and they were decomposed by ensemble empirical mode decomposition (EEMD) to identify the inherent oscillating patterns or cycles. Cross-correlation analysis and stepwise variable selection were employed to select the significant climate indices at each station. The climate indices that affect the monthly precipitation in South Korea were identified based on the selection frequencies of the selected indices at all stations. The NINO12 indices with four- and ten-month lags and AMO index with no lag were identified as indicators of monthly precipitation in South Korea. Moreover, they indicate meaningful physical information (e.g. periodic oscillations and long-term trend) inherent in the monthly precipitation. The NINO12 indices with four- and ten- month lags was a strong indicator representing periodic oscillations in monthly precipitation. In addition, the long-term trend of the monthly precipitation could be explained by the AMO index. A multiple linear regression model was constructed to investigate the influences of the identified climate indices on the prediction of monthly precipitation. Three identified climate indices successfully explained the monthly precipitation in the winter dry season. Compared to the monthly precipitation in coastal areas, the monthly precipitation in inland areas showed stronger correlation to the identified climate indices.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26259555','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26259555"><span>Scale-dependency of the global mean surface temperature trend and its implication for the recent hiatus of global warming.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lin, Yong; Franzke, Christian L E</p> <p>2015-08-11</p> <p>Studies of the global mean surface temperature trend are typically conducted at a single (usually annual or decadal) time scale. The used scale does not necessarily correspond to the intrinsic scales of the natural temperature variability. This scale mismatch complicates the separation of externally forced temperature trends from natural temperature fluctuations. The hiatus of global warming since 1999 has been claimed to show that human activities play only a minor role in global warming. Most likely this claim is wrong due to the inadequate consideration of the scale-dependency in the global surface temperature (GST) evolution. Here we show that the variability and trend of the global mean surface temperature anomalies (GSTA) from January 1850 to December 2013, which incorporate both land and sea surface data, is scale-dependent and that the recent hiatus of global warming is mainly related to natural long-term oscillations. These results provide a possible explanation of the recent hiatus of global warming and suggest that the hiatus is only temporary.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/1042792-lack-uniform-trends-increasing-spatial-variability-observed-indian-rainfall-extremes','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1042792-lack-uniform-trends-increasing-spatial-variability-observed-indian-rainfall-extremes"><span></span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Ghosh, Subimal; Das, Debasish; Kao, Shih-Chieh</p> <p></p> <p>Recent studies disagree on how rainfall extremes over India have changed in space and time over the past half century, as well as on whether the changes observed are due to global warming or regional urbanization. Although a uniform and consistent decrease in moderate rainfall has been reported, a lack of agreement about trends in heavy rainfall may be due in part to differences in the characterization and spatial averaging of extremes. Here we use extreme value theory to examine trends in Indian rainfall over the past half century in the context of long-term, low-frequency variability.We show that when generalizedmore » extreme value theory is applied to annual maximum rainfall over India, no statistically significant spatially uniform trends are observed, in agreement with previous studies using different approaches. Furthermore, our space time regression analysis of the return levels points to increasing spatial variability of rainfall extremes over India. Our findings highlight the need for systematic examination of global versus regional drivers of trends in Indian rainfall extremes, and may help to inform flood hazard preparedness and water resource management in the region.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160011512','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160011512"><span>Using Probabilistic Methods in Water Scarcity Assessments: A First Step Towards a Water Scarcity Risk Assessment Framework</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Veldkamp, Ted; Wada, Yoshihide; Aerts, Jeroen; Ward, Phillip</p> <p>2016-01-01</p> <p>Water scarcity -driven by climate change, climate variability, and socioeconomic developments- is recognized as one of the most important global risks, both in terms of likelihood and impact. Whilst a wide range of studies have assessed the role of long term climate change and socioeconomic trends on global water scarcity, the impact of variability is less well understood. Moreover, the interactions between different forcing mechanisms, and their combined effect on changes in water scarcity conditions, are often neglected. Therefore, we provide a first step towards a framework for global water scarcity risk assessments, applying probabilistic methods to estimate water scarcity risks for different return periods under current and future conditions while using multiple climate and socioeconomic scenarios.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H13N..02M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H13N..02M"><span>Temperature Trends in Montane Lakes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Melack, J. M.; Sadro, S.; Jellison, R.</p> <p>2014-12-01</p> <p>Long-term temperature trends in lakes integrate hydrological and meteorological factors. We examine temperature trends in a small montane lake with prolonged ice-cover and large seasonal snowfall and in a large saline lake. Emerald Lake, located in the Sierra Nevada (California), is representative of high-elevation lakes throughout the region. No significant trend in outflow temperature was apparent from 1991to 2012. Snowfall in the watershed accounted for 93% of the variability in average summer lake temperatures. Mono Lake (California) lies in a closed, montane basin and is hypersaline and monomictic or meromictic. Temperature profiles have been collected from 1982 to 2010. In the upper water column, the July-August-September water temperatures increased 0.8-1.0°C over the 29 years. This rate of warming is less than published estimates based on satellite-derived skin temperatures and will discussed in the context of general limnological interpretation of temperature trends.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PIAHS.379..255Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PIAHS.379..255Z"><span>Long-term changes in river system hydrology in Texas</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Yiwen; Wurbs, Ralph</p> <p>2018-06-01</p> <p>Climate change and human actives are recognized as a topical issue that change long-term water budget, flow-frequency, and storage-frequency characteristics of different river systems. Texas is characterized by extreme hydrologic variability both spatially and temporally. Meanwhile, population and economic growth and accompanying water resources development projects have greatly impacted river flows throughout Texas. The relative effects of climate change, water resources development, water use, and other factors on long-term changes in river flow, reservoir storage, evaporation, water use, and other components of the water budgets of different river basins of Texas have been simulated in this research using the monthly version of the Water Rights Analysis Package (WRAP) modelling system with input databases sets from the Texas Commission on Environmental Quality (TCEQ) and Texas Water Development Board (TWDB). The results show that long-term changes are minimal from analysis monthly precipitation depths. Evaporation rates vary greatly seasonally and for much of the state appear to have a gradually upward trend. River/reservoir system water budgets and river flow characteristics have changed significantly during the past 75 years in response to water resources development and use.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRC..121..775A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRC..121..775A"><span>A multiscale climate emulator for long-term morphodynamics (MUSCLE-morpho)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Antolínez, José Antonio A.; Méndez, Fernando J.; Camus, Paula; Vitousek, Sean; González, E. Mauricio; Ruggiero, Peter; Barnard, Patrick</p> <p>2016-01-01</p> <p>Interest in understanding long-term coastal morphodynamics has recently increased as climate change impacts become perceptible and accelerated. Multiscale, behavior-oriented and process-based models, or hybrids of the two, are typically applied with deterministic approaches which require considerable computational effort. In order to reduce the computational cost of modeling large spatial and temporal scales, input reduction and morphological acceleration techniques have been developed. Here we introduce a general framework for reducing dimensionality of wave-driver inputs to morphodynamic models. The proposed framework seeks to account for dependencies with global atmospheric circulation fields and deals simultaneously with seasonality, interannual variability, long-term trends, and autocorrelation of wave height, wave period, and wave direction. The model is also able to reproduce future wave climate time series accounting for possible changes in the global climate system. An application of long-term shoreline evolution is presented by comparing the performance of the real and the simulated wave climate using a one-line model. This article was corrected on 2 FEB 2016. See the end of the full text for details.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED485199.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED485199.pdf"><span>NAEP 1999 Long-Term Trend Technical Analysis Report: Three Decades of Student Performance. NCES 2005-484</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Allen, Nancy L.; McClellan, Catherine A.; Stoeckel, Joan J.</p> <p>2005-01-01</p> <p>This report provides an update to the technical analysis procedures documenting the 1996 National Assessment of Educational Progress (NAEP) as presented in "The NAEP 1996 Technical Report" (Allen, Carlson, and Zelenak, 1999). It describes how the 1999 long-term trend data were incorporated into the trend analyses. Since no national main…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA.....5799T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA.....5799T"><span>Reconstruction of erythemal UV irradiance at Hohenpeissenberg (1968-2001) considering trends of total ozone, cloudiness, and turbidity</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Trepte, S.; Winkler, P.</p> <p>2003-04-01</p> <p>The global mean total column ozone amount for the period 1997-2001 was approximately 3% below the 1964-1980 average. The largest ozone decreases in the northern hemisphere midlatitudes are observed during winter-spring (˜4%), with summer-autumn decreases approximately half as large. Total ozone measured at Hohenpeissenberg, Germany (48^oN, 11^oE) shows a strong decrease by about 10% since 1968, representing the long-term downward trend over Central Europe. The main consequence of this phenomenon is the expected increase of solar ultraviolet irradiation (UV-B) reaching the Earth's surface with the known harmful effects on the biosphere. Global data records of reliable routine observations of UV irradiance are still too short for accurate estimation of long-term UV variations and trends. While direct UV mesaurements at Hohenpeissenberg are available only since 1990, the long-term development of UV-B have to be reconstructed. Besides on the amount of total ozone the UV irradiation at the ground depends also on atmospheric turbidity and cloudiness. The reconstruction method is based on statistical correlations of measured UV-B data with the influencing parameters total ozone, turbidity and cloud modification factors derived from eye-observations in connection with total solar irradiance data. These observed data allow a realistic reconstruction of the UV-B time series, since no assumption on these influencing data have to be made. A model is presented, using hourly observed spectral UV-B irradiance (1990-1998), total solar irradiance, total ozone amount (daily mean) and clouds to derive erythemal UV irradiance and daily doses at Hohenpeissenberg in the period 1968-2001. A comparison with recorded UV data shows good agreement. Due to long-term total ozone loss, peak values of erythemal UV irradiance in spring and summer at clear-sky conditions have strongly increased (+4.2%/decade in June). Mean daily doses have also increased in this season (+5.4%/decade in May) but meteorological changes like reduced sunshine duration and increased cloudiness lead to a partly compensation of the ozone-loss effect in spring and to an overcompensation in autumn, where we found a long-term decrease of the daily dose (-3.0%/decade in September). Model calculations also demonstrate large year-to-year fluctuations of UV doses induced by meteorological variability, which exceed the long-term trend of the various months significantly. Nevertheless, this investigation has shown that on a long-term time scale the daily doses develop in a different way as compared to the peak values because the reasons for ozone decline (anthropogenic CFC's) and the cloud cover (hydrological cycle changes due to greenhouse effect) are caused by different phenomena.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1511082V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1511082V"><span>Global trends in vegetation phenology from 32-year GEOV1 leaf area index time series</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Verger, Aleixandre; Baret, Frédéric; Weiss, Marie; Filella, Iolanda; Peñuelas, Josep</p> <p>2013-04-01</p> <p>Phenology is a critical component in understanding ecosystem response to climate variability. Long term data records from global mapping satellite platforms are valuable tools for monitoring vegetation responses to climate change at the global scale. Phenology satellite products and trend detection from satellite time series are expected to contribute to improve our understanding of climate forcing on vegetation dynamics. The capacity of monitoring ecosystem responses to global climate change was evaluated in this study from the 32-year time series of global Leaf Area Index (LAI) which have been recently produced within the geoland2 project. The long term GEOV1 LAI products were derived from NOAA/AVHRR (1981 to 2000) and SPOT/VGT (1999 to the present) with specific emphasis on consistency and continuity. Since mid-November, GEOV1 LAI products are freely available to the scientific community at geoland2 portal (www.geoland2.eu/core-mapping-services/biopar.html). These products are distributed at a dekadal time step for the period 1981-2000 and 2000-2012 at 0.05° and 1/112°, respectively. The use of GEOV1 data covering a long time period and providing information at dense time steps are expected to increase the reliability of trend detection. In this study, GEOV1 LAI time series aggregated at 0.5° spatial resolution are used. The CACAO (Consistent Adjustment of the Climatology to Actual Observations) method (Verger et al, 2013) was applied to characterize seasonal anomalies as well as identify trends. For a given pixel, CACAO computes, for each season, the time shift and the amplitude difference between the current temporal profile and the climatology computed over the 32 years. These CACAO parameters allow quantifying shifts in the timing of seasonal phenology and inter-annual variations in magnitude as compared to the average climatology. Interannual variations in the timing of the Start of Season and End of Season, Season Length and LAI level in the peak of the growing season are analyzed. Trend analysis with robust statistical test of significance is conducted. Climate variables (precipitation, temperature, radiation) are then used to interpret the anomaly patterns detected in vegetation response.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25099211','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25099211"><span>Changes in climate variability with reference to land quality and agriculture in Scotland.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Brown, Iain; Castellazzi, Marie</p> <p>2015-06-01</p> <p>Classification and mapping of land capability represents an established format for summarising spatial information on land quality and land-use potential. By convention, this information incorporates bioclimatic constraints through the use of a long-term average. However, climate change means that land capability classification should also have a dynamic temporal component. Using an analysis based upon Land Capability for Agriculture in Scotland, it is shown that this dynamism not only involves the long-term average but also shorter term spatiotemporal patterns, particularly through changes in interannual variability. Interannual and interdecadal variations occur both in the likelihood of land being in prime condition (top three capability class divisions) and in class volatility from year to year. These changing patterns are most apparent in relation to the west-east climatic gradient which is mainly a function of precipitation regime and soil moisture. Analysis is also extended into the future using climate results for the 2050s from a weather generator which show a complex interaction between climate interannual variability and different soil types for land quality. In some locations, variability of land capability is more likely to decrease because the variable climatic constraints are relaxed and the dominant constraint becomes intrinsic soil properties. Elsewhere, climatic constraints will continue to be influential. Changing climate variability has important implications for land-use planning and agricultural management because it modifies local risk profiles in combination with the current trend towards agricultural intensification and specialisation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120010403','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120010403"><span>Satellite Observations of Antarctic Sea Ice Thickness and Volume</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kurtz, Nathan; Markus, Thorsten</p> <p>2012-01-01</p> <p>We utilize satellite laser altimetry data from ICESat combined with passive microwave measurements to analyze basin-wide changes in Antarctic sea ice thickness and volume over a 5 year period from 2003-2008. Sea ice thickness exhibits a small negative trend while area increases in the summer and fall balanced losses in thickness leading to small overall volume changes. Using a five year time-series, we show that only small ice thickness changes of less than -0.03 m/yr and volume changes of -266 cu km/yr and 160 cu km/yr occurred for the spring and summer periods, respectively. The calculated thickness and volume trends are small compared to the observational time period and interannual variability which masks the determination of long-term trend or cyclical variability in the sea ice cover. These results are in stark contrast to the much greater observed losses in Arctic sea ice volume and illustrate the different hemispheric changes of the polar sea ice covers in recent years.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28924195','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28924195"><span>Patterns of change in high frequency precipitation variability over North America.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Roque-Malo, Susana; Kumar, Praveen</p> <p>2017-09-18</p> <p>Precipitation variability encompasses attributes associated with the sequencing and duration of events of the full range of magnitudes. However, climate change studies have largely focused on extreme events. Using analyses of long-term weather station data, we show that high frequency events, such as fraction of wet days in a year and average duration of wet and dry periods, are undergoing significant changes across North America. Further, these changes are more prevalent and larger than those associated with extremes. Such trends also exist for events of a range of magnitudes. Existence of localized clusters with opposing trend to that of broader geographic variation illustrates the role of microclimate and other drivers of trends. Such hitherto unknown patterns over the entire North American continent have the potential to significantly inform our characterization of the resilience and vulnerability of a broad range of ecosystems and agricultural and socio-economic systems. They can also set new benchmarks for climate model assessments.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H34C..08H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H34C..08H"><span>Long-term monitoring of river basins: strengths and weaknesses, opportunities and threats</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Howden, N. J. K.; Burt, T. P.</p> <p>2016-12-01</p> <p>In a world where equilibrium is more and more uncommon, monitoring is an essential way to discover whether undesirable change is taking place. Monitoring requires a deliberate plan of action: the regular collection and processing of information. Long-term data reveal important patterns, allowing trends, cycles, and rare events to be identified. This is particularly important for complex systems where signals may be subtle and slow to emerge. Moreover, very long data sets are essential to test hypotheses undreamt of at the time the monitoring was started. This overview includes long time series from UK river basins showing how hydrology and water quality have changed over time - and continue to change. An important conclusion is the long time frame of system recovery, well beyond the normal lifetime of individual governments or research grants. At a time of increasing hydroclimatic variability, long time series remain crucially important; in particular, continuity of observations is vital at key benchmark sites.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/1054990-long-term-data-reveal-patterns-controls-stream-water-chemistry-forested-stream-walker-branch-tennessee','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1054990-long-term-data-reveal-patterns-controls-stream-water-chemistry-forested-stream-walker-branch-tennessee"><span>Long-Term Data Reveal Patterns and Controls on Stream Water Chemistry in a Forested Stream: Walker Branch, Tennessee</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Lutz, Brian D; Mulholland, Patrick J; Bernhardt, Emily</p> <p>2012-01-01</p> <p>We present 20 years of weekly stream water chemistry, hydrology, and climate data for the Walker Branch watershed in eastern Tennessee, USA. Since 1989, the watershed has experienced a similar to 1.08 degrees C increase in mean annual temperature, a similar to 20% decline in precipitation, and a similar to 30% increase in forest evapotranspiration rates. As a result, stream runoff has declined by similar to 34%. We evaluate long-term trends in stream water concentrations and fluxes for nine solutes and use wet deposition data to calculate approximate watershed input-output budgets. Dissolved constituents were classified as geochemical solutes (Ca2+, Mg2+,more » and SO42-) or nutrients (NH4+, NO3-, soluble reactive phosphorus [SRP], total soluble nitrogen [TSN], total soluble phosphorus [TSP], and dissolved organic carbon [DOC]). Geochemical solutes are predominantly controlled by discharge, and the long-term changes in catchment hydrology have led to significant trends in the concentrations and fluxes of these solutes. Further, the trends in geochemical solute concentrations indicate shifting soil flowpath contributions to streamflow generation through time, with deep groundwater having a greater proportional contribution in recent years. Despite dramatic changes in watershed runoff, there were no trends in inorganic nutrient concentrations (NH4+, NO3-, and SRP). While most nutrients entering the watershed are retained, stream fluxes of nutrient solutes have declined significantly as a result of decreasing runoff. Nutrient concentrations in the stream exhibit large seasonality controlled by in-stream biological uptake. Stream benthic communities are sensitive to hydrologic disturbance, and changes in the frequency or intensity of storm events through time can affect nutrient fluxes. Stream NO3- concentrations are also sensitive to drought, with concentrations decreasing (increasing) if conditions during the three years prior to the time of sampling were drier (wetter) than the long-term mean. Future changes in the incidence of storm events, as well as the number and duration of droughts, have the potential to significantly alter watershed nutrient losses. Our analysis indicates that changing climates can differentially affect watershed element cycles either through changes in biogeochemical process rates or through changes in catchment hydrology. Furthermore, climate change can include both long-term trending in mean climate variables, as well as changes in the frequency and intensity of storms and droughts, with each of these types of change having distinct effects on the biological and geochemical processes governing different solutes.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.G51B..07W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.G51B..07W"><span>Changes in US extreme sea levels and the role of large scale climate variations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wahl, T.; Chambers, D. P.</p> <p>2015-12-01</p> <p>We analyze a set of 20 tide gauge records covering the contiguous United States (US) coastline and the period from 1929 to 2013 to identify long-term trends and multi-decadal variations in extreme sea levels (ESLs) relative to changes in mean sea level (MSL). Significant but small long-term trends in ESLs above/below MSL are found at individual sites along most coastline stretches, but are mostly confined to the southeast coast and the winter season when storm surges are primarily driven by extra-tropical cyclones. We identify six regions with broadly coherent and considerable multi-decadal ESL variations unrelated to MSL changes. Using a quasi-non-stationary extreme value analysis approach we show that the latter would have caused variations in design relevant return water levels (RWLs; 50 to 200 year return periods) ranging from ~10 cm to as much as 110 cm across the six regions. To explore the origin of these temporal changes and the role of large-scale climate variability we develop different sets of simple and multiple linear regression models with RWLs as dependent variables and climate indices, or tailored (toward the goal of predicting multi-decadal RWL changes) versions of them, and wind stress curl as independent predictors. The models, after being tested for spatial and temporal stability, explain up to 97% of the observed variability at individual sites and almost 80% on average. Using the model predictions as covariates for the quasi-non-stationary extreme value analysis also significantly reduces the range of change in the 100-year RWLs over time, turning a non-stationary process into a stationary one. This highlights that the models - when used with regional and global climate model output of the predictors - should also be capable of projecting future RWL changes to be used by decision makers for improved flood preparedness and long-term resiliency.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28953942','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28953942"><span>Aging and death-associated changes in serum albumin variability over the course of chronic hemodialysis treatment.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nakazato, Yuichi; Kurane, Riichi; Hirose, Satoru; Watanabe, Akihisa; Shimoyama, Hiromi</p> <p>2017-01-01</p> <p>Several epidemiological studies have demonstrated associations between variability in a number of biological parameters and adverse outcomes. As the variability may reflect impaired homeostatic regulation, we assessed albumin variability over time in chronic hemodialysis (HD) patients. Data from 1346 subjects who received chronic HD treatment from May 2001 to February 2015 were analyzed according to three phases of HD treatment: post-HD initiation, during maintenance HD treatment, and before death. The serum albumin values were grouped according to the time interval from HD initiation or death, and the yearly trends for both the albumin levels and the intra-individual albumin variability (quantified by the residual coefficient of variation: Alb-rCV) were examined. The HD initiation and death-associated changes were also analyzed using generalized additive mixed models. Furthermore, the long-term trend throughout the maintenance treatment period was evaluated separately using linear regression models. Albumin levels and variability showed distinctive changes during each of the 3 periods. After HD initiation, albumin variability decreased and reached a nadir within a year. During the subsequent maintenance treatment period (interquartile range = 5.2-11.0 years), the log Alb-rCV showed a significant upward trend (mean slope: 0.011 ± 0.035 /year), and its overall mean was -1.49 ± 0.08 (equivalent to an Alb-rCV of 3.22%). During the 1-2 years before death, this upward trend clearly accelerated, and the mean log Alb-rCV in the last year of life was -1.36 ± 0.17. The albumin levels and variability were negatively correlated with each other and exhibited exactly opposite movements throughout the course of chronic HD treatment. Different from the albumin levels, albumin variability was not dependent on chronological age but was independently associated with an individual's aging and death process. The observed upward trend in albumin variability seems to be consistent with a presumed aging-related decline in homeostatic capacity.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.7908V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.7908V"><span>Climatic change effects on hydro-metereological variables in the Alps: a case study on the upper Arve catchment at Chamonix (France) over the last 50 years</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Viani, Alessandra; Condom, Thomas; Bacchi, Baldassare; Zin, Isabella; Six, Delphine; Gottardi, Frederic; Rabatel, Antoine; Morin, Samuel</p> <p>2016-04-01</p> <p>Hydrological changes in partially glaciated catchments are expected under future climate scenarios, with consequences for water availability and management at catchment and regional scales. In order to correctly predict the magnitude of such changes and envisage adaptation and/or mitigation measures against water related hazards, a good understanding of the water cycle dynamics at different spatial and temporal scales is needed. The Upper Arve catchment in Chamonix (202 square kilometers), situated in the French Northern Alps, between the two massifs of Mont Blanc and Aiguilles Rouges, is a perfect case study for evaluating the sensitivity of the alpine water cycle to climate change. It is highly glaciated (32% of the total area in 2012) with three important glaciers: Glacier du Tour, Glacier d'Argentiere and Glacier de la Mer de Glace. Its elevation ranges from 1025 up to 4295 m a.s.l. and the exposure of the ice cover is generally north and east oriented. Long term time-series exist of (i) glacier mass balance, (ii) meteorological (in-situ and reanalyses) and (iii) hydrological data. The objectives of the presented study were: 1 - To characterize the inter-annual regimes of the different climatological and hydrological variables: precipitation, temperature and discharge; 2 - To estimate trends on the previous variables, at different temporal scales (annual and monthly) for different altitudes, and compare them to usually observed values in alpine regions; 3 - To infer from the previous statistical analyses and from a cross-analysis between the different considered variables the catchment's hydrological evolution during the last 50 years. Results showed precipitation, temperature and discharge regimes typical of high mountainous partially glaciated catchments. In the long term period, this catchment is characterized by an evident retreat of glacier. Long term trends over the past five decades show no significant change in the annual amount of precipitation. At the same time, a significantly increase of the number of rainy or snowy days is observed, related to an increase of the number of days with small precipitation intensities. Particularly, we have estimated a significant positive trend in the number of liquid precipitation days with intensities less than 10 mm per day (+ 49 days/year from 1934 to 2014). On the other hand, temperature increases significantly of about 0.3 K per decade in average over the lower part of the catchment (between 1100 and 2100 m a.s.l.). This increase is slightly greater than the previous estimated trends over the French Alps. At the same time, a weaker trend is estimated at higher altitudes, from 3000 to 3600 m a.s.l., which is a more surprising result with respect to the previous published values. Finally, an hydrological regime shift is observed with a melting season occurring earlier for the last two decades.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ThApC.117..625D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ThApC.117..625D"><span>Variability and trends of local/regional scale surface climate in northern Africa during the twentieth century</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Djomou, Zéphirin Yepdo; Monkam, David; Woafo, Paul</p> <p>2014-08-01</p> <p>Four regions are detected in northern Africa (20° W-40° E, 0-30° N) by applying the cluster analysis method on the annual rainfall anomalies of the period 1901-2000. The first region (R1), an arid land, covers essentially the north of 17.75° N from west to east of the study zone. The second region (R2), a semiarid land with a Sahelian climate, less warm than the dry climate of R1, is centred on Chad, with almost regular extension to the west towards Mauritania, and to the east, including the north of the Central African Republic and the Sudan. The region 3 (R3), a wet land, is centred on the Ivory Coast and covers totally Liberia, the south part of Ghana, Togo, Benin and the southwest of Nigeria. The fourth region (R4), corresponding to the wet equatorial forest, covers a part of Senegal, the Central Africa, the south of Sudan and a part of Ethiopia. An analysis of observed temperature and precipitation variability and trends throughout the twentieth century over these regions is presented. Summer, winter and annual data are examined using a range of variability measures. Statistically, significant warming trends are found over the majority of regions. The trends have a magnitude of up to 1.5 K per century. Only a few precipitation trends are statistically significant. Regional temperature and precipitation show pronounced variability at scales from interannual to multi-decadal. The interannual variability shows significant variations and trends throughout the century, the latter being mostly negative for precipitation and both positive and negative for temperature. Temperature and precipitation anomalies show a chaotic-type behaviour in which the regional conditions oscillate around the long-term mean trend and occasionally fall into long-lasting (up to 10 years or more) anomaly regimes. A generally modest temporal correlation is found between anomalies of different regions and between temperature and precipitation anomalies for the same region. This correlation is mostly positive for temperature in cases of adjacent regions. Several cases of negative interregional precipitation anomaly correlation are found. The El Niño Southern Oscillation significantly affects the anomaly variability patterns over a number of regions, mainly regions 3 (R3) and 4 (R4), while the North Atlantic Oscillation significantly affects the variability over arid and semiarid regions, R1 and R2.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AtmRe.198...97S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AtmRe.198...97S"><span>Long-term trends in daily temperature extremes in Iraq</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salman, Saleem A.; Shahid, Shamsuddin; Ismail, Tarmizi; Chung, Eun-Sung; Al-Abadi, Alaa M.</p> <p>2017-12-01</p> <p>The existence of long-term persistence (LTP) in hydro-climatic time series can lead to considerable change in significance of trends. Therefore, past findings of climatic trend studies that did not consider LTP became a disputable issue. A study has been conducted to assess the trends in temperature and temperature extremes in Iraq in recent years (1965-2015) using both ordinary Mann-Kendal (MK) test; and the modified Mann-Kendall (m-MK) test, which can differentiate the multi-decadal oscillatory variations from secular trends. Trends in annual and seasonal minimum and maximum temperatures, diurnal temperature range (DTR), and 14 temperature-related extremes were assessed. MK test detected the significant increases in minimum and maximum temperature at all stations, where m-MK test detected at 86% and 80% of all stations, respectively. The temperature in Iraq is increasing 2 to 7 times faster than global temperature rise. The minimum temperature is increasing more (0.48-1.17 °C/decade) than maximum temperature (0.25-1.01 °C/decade). Temperature rise is higher in northern Iraq and in summer. The hot extremes particularly warm nights are increasing all over Iraq at a rate of 2.92-10.69 days/decade, respectively. On the other hand, numbers of cold days are decreasing at some stations at a rate of - 2.65 to - 8.40 days/decade. The use of m-MK test along with MK test confirms the significant increase in temperature and some of the temperature extremes in Iraq. This study suggests that trends in many temperature extremes in the region estimated in previous studies using MK test may be due to natural variability of climate, which empathizes the need for validation of the trends by considering LTP in time series.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/48838','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/48838"><span>Long-term trends of changes in pine and oak foliar nitrogen metabolism in response to chronic nitrogen amendments at Harvard Forest, MA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Rakesh Minocha; Swathi A. Turlapati; Stephanie Long; William H. McDowell; Subhash C. Minocha</p> <p>2015-01-01</p> <p>We evaluated the long-term (1995-2008) trends in foliar and sapwood metabolism, soil solution chemistry and tree mortality rates in response to chronic nitrogen (N) additions to pine and hardwood stands at the Harvard Forest Long Term Ecological Research (LTER) site. Common stress-related metabolites like polyamines (PAs), free amino acids (AAs) and inorganic elements...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23284734','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23284734"><span>An exotic long-term pattern in stock price dynamics.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wei, Jianrong; Huang, Jiping</p> <p>2012-01-01</p> <p>To accurately predict the movement of stock prices is always of both academic importance and practical value. So far, a lot of research has been reported to help understand the behavior of stock prices. However, some of the existing theories tend to render us the belief that the time series of stock prices are unpredictable on a long-term timescale. The question arises whether the long-term predictability exists in stock price dynamics. In this work, we analyze the price reversals in the US stock market and the Chinese stock market on the basis of a renormalization method. The price reversals are divided into two types: retracements (the downward trends after upward trends) and rebounds (the upward trends after downward trends), of which the intensities are described by dimensionless quantities, R(t) and R(b), respectively. We reveal that for both mature and emerging markets, the distribution of either retracements R(t) or rebounds R(b) shows two characteristic values, 0.335 and 0.665, both of which are robust over the long term. The methodology presented here provides a way to quantify the stock price reversals. Our findings strongly support the existence of the long-term predictability in stock price dynamics, and may offer a hint on how to predict the long-term movement of stock prices.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26444202','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26444202"><span>Electromagnetic fields from mobile phone base station - variability analysis.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bienkowski, Pawel; Zubrzak, Bartlomiej</p> <p>2015-09-01</p> <p>The article describes the character of electromagnetic field (EMF) in mobile phone base station (BS) surroundings and its variability in time with an emphasis on the measurement difficulties related to its pulse and multi-frequency nature. Work also presents long-term monitoring measurements performed recently in different locations in Poland - small city with dispersed building development and in major polish city - dense urban area. Authors tried to determine the trends in changing of EMF spectrum analyzing daily changes of measured EMF levels in those locations. Research was performed using selective electromagnetic meters and also EMF meter with spectrum analysis.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25602878','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25602878"><span>Relation between annual trends in food pantry use and long-term unemployment in New York State, 2002-2012.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shackman, Gene; Yu, Chengxuan; Edmunds, Lynn S; Clarke, Lewis; Sekhobo, Jackson P</p> <p>2015-03-01</p> <p>We examined the correlation between trends in meals provided through food pantries and long-term unemployment from 2002 through 2012. The New York State Hunger Prevention and Nutrition Assistance Program provided about 192 million meals through food pantries in 2012-double the number before the Great Recession. Annual food pantry use was strongly correlated with long-term unemployment and remained on an upward trend from 2006 through 2012, even after the Great Recession had ended. These findings suggest that efforts to reduce hunger and food insecurity should continue to be priorities.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSHE33A..08D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSHE33A..08D"><span>Long-Term Trends and Variability in Spring Development of Calanus finmarchicus in the Southeastern Norwegian Sea during 1996-2012</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dupont, N.; Bagøien, E.; Melle, W.</p> <p>2016-02-01</p> <p>Calanus finmarchicus is the dominant copepod species in the Norwegian Sea in terms of biomass, playing a key role in the ecosystem by transferring energy from primary producers to higher trophic levels. This study analyses the long-term trend of a 17-year time series (1996-2012) on abundance of adult Calanus finmarchicus in the Atlantic water-mass of the southern Norwegian Sea during spring. The long-term trend in spring abundance was assessed by using Generalised Additive Models, while simultaneously accounting for both general population development and inter-annual variation in population development throughout the study period. In one model, we focus on inter-annual changes in timing of the Calanus spring seasonal development by including Mean Stage Composition as a measure for state of population development. Following a short increase during the years 1996 to 2000, the abundance of Calanus finmarchicus decreased strongly until about the year 2010. For the two last years of the studied period, 2011-2012, increasing population abundances are suggested but with less certainty. The model results suggest that the analysis is capturing the G0 generation, displaying a peak for the adults in about mid-April. Inter-annual differences in spring seasonal development, with the peak of adults shifting towards earlier in the season as well as a shorter generation time are suggested. Considering the importance of Calanus finmarchicus as food for planktivorous predators in the Norwegian Sea, our time series analysis suggests relevant changes both with respect to the spring abundance and timing of this food source. The next step is to relate variation in the Calanus time series to environmental factors with special emphasis on climatic drivers.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28277951','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28277951"><span>Within-Winter Flexibility in Muscle Masses, Myostatin, and Cellular Aerobic Metabolic Intensity in Passerine Birds.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Swanson, David L; King, Marisa O; Culver, William; Zhang, Yufeng</p> <p></p> <p>Metabolic rates of passerine birds are flexible traits that vary both seasonally and among and within winters. Seasonal variation in summit metabolic rates (M sum = maximum thermoregulatory metabolism) in birds is consistently correlated with changes in pectoralis muscle and heart masses and sometimes with variation in cellular aerobic metabolic intensity, so these traits might also be associated with shorter-term, within-winter variation in metabolic rates. To determine whether these mechanisms are associated with within-winter variation in M sum , we examined the effects of short-term (ST; 0-7 d), medium-term (MT; 14-30 d), and long-term (LT; 30-yr means) temperature variables on pectoralis muscle and heart masses, pectoralis expression of the muscle-growth inhibitor myostatin and its metalloproteinase activators TLL-1 and TLL-2, and pectoralis and heart citrate synthase (CS; an indicator of cellular aerobic metabolic intensity) activities for two temperate-zone resident passerines, house sparrows (Passer domesticus) and dark-eyed juncos (Junco hyemalis). For both species, pectoralis mass residuals were positively correlated with ST temperature variables, suggesting that cold temperatures resulted in increased turnover of pectoralis muscle, but heart mass showed little within-winter variation for either species. Pectoralis mRNA and protein expression of myostatin and the TLLs were only weakly correlated with ST and MT temperature variables, which is largely consistent with trends in muscle masses for both species. Pectoralis and heart CS activities showed weak and variable trends with ST temperature variables in both species, suggesting only minor effects of temperature variation on cellular aerobic metabolic intensity. Thus, neither muscle or heart masses, regulation by the myostatin system, nor cellular aerobic metabolic intensity varied consistently with winter temperature, suggesting that other factors regulate within-winter metabolic variation in these birds.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.6074M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.6074M"><span>Elephant overflows: Multi-annual variability in Weddell Sea Deep Water driven by surface forcing</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meijers, Andrew; Meredith, Michael; Abrahamsen, Povl; Naviera-Garabato, Alberto; Ángel Morales Maqueda, Miguel; Polzin, Kurt</p> <p>2015-04-01</p> <p>The volume of the deepest and densest water mass in Drake Passage, Lower Weddell Sea Deep Water (LWSDW), is shown to have been decreasing over the last 20 years of observations, with an associated reduction in density driven by freshening. Superimposed on this long term trend is a multi-annual oscillation with a period of 3-5 years. This variability only appears in Drake Passage; observations in the east of the Scotia Sea show a similar long term trend, but with no apparent multi-annual variability. Clues as to the source of this variability may be found on the continental slope at approximately 1000 m immediately north of Elephant Island on the northern tip of the Antarctic Peninsula. Here there is an intermittent westward flowing cold/fresh slope current whose volume and properties are strongly correlated with the LWSDW multi-annual variability, although leading the LWSDW by around one year. As the slope current and LWSDW are separated from each other both geographically and in water mass characteristics, their co-variability implies that they are responding to a common forcing, while the lag between deep LWSDW and shallow slope current provides information on the timescale of this response. A newly available high resolution temperature and salinity multi-year time series from the Elephant Island slope at 1000 m is compared with reanalysis and model derived surface fluxes, sea ice extent and wind stress. We find that there are strong positive relationships between the surface wind stress and heat flux over the shelf at the tip of the Antarctic Peninsula and the properties of the slope current at 1000 m on seasonal to annual timescales. We use tracer release experiments in the Southern Ocean State Estimate (SOSE) model to investigate the lag between the slope current and LWSDW timeseries and hypothesise that the observed multi-annual variability in both water masses is driven by surface forcing over the shelf and the overflow of modified water from the slope in the north-west Weddell Sea. The lag observed between the two time series is due to the difference in water mass paths to the observation points in Drake Passage. We discuss the role of atmospheric modes of variability such as ENSO and SAM, as well as climate trends, on this relationship and their potential impact on future LWSDW export.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29198096','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29198096"><span>Prognostic Factors and Decision Tree for Long-term Survival in Metastatic Uveal Melanoma.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lorenzo, Daniel; Ochoa, María; Piulats, Josep Maria; Gutiérrez, Cristina; Arias, Luis; Català, Jaum; Grau, María; Peñafiel, Judith; Cobos, Estefanía; Garcia-Bru, Pere; Rubio, Marcos Javier; Padrón-Pérez, Noel; Dias, Bruno; Pera, Joan; Caminal, Josep Maria</p> <p>2017-12-04</p> <p>The purpose of this study was to demonstrate the existence of a bimodal survival pattern in metastatic uveal melanoma. Secondary aims were to identify the characteristics and prognostic factors associated with long-term survival and to develop a clinical decision tree. The medical records of 99 metastatic uveal melanoma patients were retrospectively reviewed. Patients were classified as either short (≤ 12 months) or long-term survivors (> 12 months) based on a graphical interpretation of the survival curve after diagnosis of the first metastatic lesion. Ophthalmic and oncological characteristics were assessed in both groups. Of the 99 patients, 62 (62.6%) were classified as short-term survivors, and 37 (37.4%) as long-term survivors. The multivariate analysis identified the following predictors of long-term survival: age ≤ 65 years (p=0.012) and unaltered serum lactate dehydrogenase levels (p=0.018); additionally, the size (smaller vs. larger) of the largest liver metastasis showed a trend towards significance (p=0.063). Based on the variables significantly associated with long-term survival, we developed a decision tree to facilitate clinical decision-making. The findings of this study demonstrate the existence of a bimodal survival pattern in patients with metastatic uveal melanoma. The presence of certain clinical characteristics at diagnosis of distant disease is associated with long-term survival. A decision tree was developed to facilitate clinical decision-making and to counsel patients about the expected course of disease.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC41A1006Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC41A1006Z"><span>Tropical rainforests dominate multi-decadal variability of the global carbon cycle</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, X.; Wang, Y. P.; Peng, S.; Rayner, P. J.; Silver, J.; Ciais, P.; Piao, S.; Zhu, Z.; Lu, X.; Zheng, X.</p> <p>2017-12-01</p> <p>Recent studies find that inter-annual variability of global atmosphere-to-land CO2 uptake (NBP) is dominated by semi-arid ecosystems. However, the NBP variations at decadal to multi-decadal timescales are still not known. By developing a basic theory for the role of net primary production (NPP) and heterotrophic respiration (Rh) on NBP and applying it to 100-year simulations of terrestrial ecosystem models forced by observational climate, we find that tropical rainforests dominate the multi-decadal variability of global NBP (48%) rather than the semi-arid lands (35%). The NBP variation at inter-annual timescales is almost 90% contributed by NPP, but across longer timescales is progressively controlled by Rh that constitutes the response from the NPP-derived soil carbon input (40%) and the response of soil carbon turnover rates to climate variability (60%). The NBP variations of tropical rainforests is modulated by the ENSO and the PDO through their significant influences on temperature and precipitation at timescales of 2.5-7 and 25-50 years, respectively. This study highlights the importance of tropical rainforests on the multi-decadal variability of global carbon cycle, suggesting that we need to carefully differentiate the effect of NBP long-term fluctuations associated with ocean-related climate modes on the long-term trend in land sink.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A13M..04G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A13M..04G"><span>Analyzing nearly four decades of historical radiosonde observations of tropical tropopause layer and cold-point temperatures</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gilford, D.; Randel, W. J.</p> <p>2017-12-01</p> <p>An understanding of historical trends and variability in the thermal structure of the tropical tropopause layer (TTL) is important for assessing climate and investigating TTL processes. In particular, the cold-point tropopause (CPT) plays an important role in stratospheric dehydration, the potential intensities of tropical cyclones, and other forms of stratospheric-tropospheric coupling. Uncertainties and biases of in-situ observations, however, make long-term estimation of TTL temperatures challenging, especially in the early decades of the satellite era. The goal of this study is to construct and analyze a long-term record of radiosondes temperatures with minimal biases. Temperature observations from 1979-present are drawn from the Integrated Global Radiosonde Archive version 2 (IGRA2). Vertically integrated radiosonde temperatures are compared with brightness temperatures from the Microwave Sounding Units (MSU) Lower Stratosphere channel to identify the radiosonde stations with the smallest temporal discontinuities. Insights from this comparison highlight the importance of independent measurements when evaluating TTL temperatures. The 38-year dataset constructed from IGRA2 stations with the smallest biases spans the tropics and has high vertical resolution, permitting reasonable estimates of the CPT temperature. Radiosonde temperatures show good agreement with GPS radio occultation measurements over the past decade. A multivariate regression model incorporating the Quasi-Biennial Oscillation and the El Nino Southern Oscillation is fit to the deseasonalized data to evaluate the spatial and temporal structures in its variability. Long-term trends in CPT temperatures are considered in the context of historical estimates from climate models. Correlations with TTL water vapor concentrations from the Stratospheric Water and OzOne Satellite Homogenized (SWOOSH) data set suggest a strong relationship between the historically observed CPT temperatures and dehydration.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A51F2135Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A51F2135Z"><span>Decadal Trends and Variability of Tropospheric Ozone over Oil and Gas Regions over 2005 - 2015</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, Y.; Mao, H.; Sive, B. C.</p> <p>2017-12-01</p> <p>Tropospheric ozone (O3), which is produced largely by photochemical oxidation of nitrogen oxides (NOx) and volatile organic compounds, is a serious and ubiquitous air pollutant with strong negative health effects. Recent technological innovations such as horizontal drilling and hydraulic fracturing have accelerated oil and natural gas production in the U.S. since 2005. The additional input of O3 precursors from expanding natural gas production might prolong the effort to comply the current O3 standard (70 ppbv). The objective of this study is to investigate the impact of oil and gas extractions on variability and long term trends of O3 in the intermountain west under varying meteorological conditions. We investigated long-term O3 trends at 13 rural sites, which were within 100 km of the shale play in the U.S. intermountain west. Significant decreasing trends (-0.35 - -3.38 ppbv yr-1) were found in seasonal O3 design values at six sites in spring, summer, or fall, while no trends were found in wintertime O3 at any sites. Wintertime O3 at each site showed strong and consistent interannual variation over 2006 - 2015, and was negatively correlated with the Arctic Oscillation (AO) Index. The negative correlation was a result of multiple factors, such as in situ O3 photochemical production, stratospheric intrusion, and transport from the Arctic and California. In summer, wildfire emissions were the dominate driver to the interannual variations of high percentiles O3 at each site, while meteorological conditions (i.e., temperature and relative humidity) determined the interannual variations of low percentiles O3. Box model simulations indicated that O3 production rates were 31.51 ppbv h-1 over winters of 2012 - 2014 and 32.12 ppbv h-1 in summer 2014 around shale gas extraction regions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A23E2405P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A23E2405P"><span>Overview of the Long-term Ozone Trends and Uncertainties in the Stratosphere(LOTUS) SPARC Activity</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Petropavlovskikh, I. V.; Hubert, D.; Godin-Beekman, S.; Damadeo, R. P.; Sofieva, V.; Hassler, B.</p> <p>2017-12-01</p> <p>WMO/UNEP Assessments on the state of the ozone layer (aka Ozone Assessments) require an accurate evaluation of both total ozone and ozone profile long-term trends. These trend results are of utmost importance in order to evaluate the success of the Montreal Protocol with regards to the recovery of the ozone layer and the effect of climate change on this recovery, in the main regions of the stratosphere (polar, mid-latitudes, tropics). A previous activity sponsored by SPARC, IO3C, IGACO-O3 and NDACC (SI2N) successfully provided estimates of ozone profile decreasing trend in the period 1979 - 1997 and recovery trend in the period 1998 -2012, from a variety of long term records, however its results were different from those published in the WMO 2014 Ozone Assessment report. For the WMO/UNEP 2018 Ozone Assessment, a clear understanding of ozone trends and their significance as a function of altitude and latitude is still needed, nearly 20 years after the peak of ozone depleting substances in the stratosphere. In the most recent years, new merged satellite data sets and long awaited homogenized ozonesonde data series have been produced. There is thus a strong interest in the scientific community to understand limitations in determining significance of ozone recovery. In order to address the issues left pending after the end of SI2N, a comprehensive evaluation of all long term data sets available together with their relative drifts was performed through the SPARC LOTUS (Long-term Ozone Trends and uncertainties in Stratosphere) activity. Evaluation of consistencies in results from various statistical trend regression models, sensitivity to the selection of predictors, evaluation of sampling-related uncertainties and impact of the measurement error propagation on ozone trend calculation was among subjects of investigation. This presentation will provide overview of the LOTUS project goals, provide highlights of the results and discuss the future goals.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1222384-retrospective-investigation-energy-efficiency-standards-policies-may-have-accelerated-long-term-declines-appliance-costs','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1222384-retrospective-investigation-energy-efficiency-standards-policies-may-have-accelerated-long-term-declines-appliance-costs"><span>A retrospective investigation of energy efficiency standards: Policies may have accelerated long term declines in appliance costs</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Van Buskirk, R. D.; Kantner, C. L. S.; Gerke, B. F.; ...</p> <p>2014-11-14</p> <p>We perform a retrospective investigation of multi-decade trends in price and life-cycle cost (LCC) for home appliances in periods with and without energy efficiency (EE) standards and labeling polices. In contrast to the classical picture of the impact of efficiency standards, the introduction and updating of appliance standards is not associated with a long-term increase in purchase price; rather, quality-adjusted prices undergo a continued or accelerated long-term decline. In addition, long term trends in appliance LCCs—which include operating costs—consistently show an accelerated long term decline with EE policies. We also show that the incremental price of efficiency improvements has declinedmore » faster than the baseline product price for selected products. These observations are inconsistent with a view of EE standards that supposes a perfectly competitive market with static supply costs. These results suggest that EE policies may be associated with other forces at play, such as innovation and learning-by-doing in appliance production and design, that can affect long term trends in quality-adjusted prices and LCCs.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/9499656','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/9499656"><span>Emerging trends in the finance and delivery of long-term care: public and private opportunities and challenges.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cohen, M A</p> <p>1998-02-01</p> <p>A number of key trends are emerging in long-term care related to financing, new models of service delivery, and shifts in consumer expectations and preferences. Taken together, changes occurring in these areas point to a rapidly transforming long-term care landscape. Financing responsibility is shifting away from the federal government to states, individuals, and their families; providers are integrating and managing acute and long-term care services and adding new services to the continuum of care; and consumers are thinking more seriously about how to plan and pay for their future care needs, as well as how to independently navigate the long-term care system.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JHyd..555..108C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JHyd..555..108C"><span>Oscillations and trends of river discharge in the southern Central Andes and linkages with climate variability</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Castino, Fabiana; Bookhagen, Bodo; Strecker, Manfred R.</p> <p>2017-12-01</p> <p>This study analyzes the discharge variability of small to medium drainage basins (102-104 km2) in the southern Central Andes of NW Argentina. The Hilbert-Huang Transform (HHT) was applied to evaluate non-stationary oscillatory modes of variability and trends, based on four time series of monthly-normalized discharge anomaly between 1940 and 2015. Statistically significant trends reveal increasing discharge during the past decades and document an intensification of the hydrological cycle during this period. An Ensemble Empirical Mode Decomposition (EEMD) analysis revealed that discharge variability in this region can be best described by five quasi-periodic statistically significant oscillatory modes, with mean periods varying from 1 to ∼20 y. Moreover, we show that discharge variability is most likely linked to the phases of the Pacific Decadal Oscillation (PDO) at multi-decadal timescales (∼20 y) and, to a lesser degree, to the Tropical South Atlantic SST anomaly (TSA) variability at shorter timescales (∼2-5 y). Previous studies highlighted a rapid increase in discharge in the southern Central Andes during the 1970s, inferred to have been associated with the global 1976-77 climate shift. Our results suggest that the rapid discharge increase in the NW Argentine Andes coincides with the periodic enhancement of discharge, which is mainly linked to a negative to positive transition of the PDO phase and TSA variability associated with a long-term increasing trend. We therefore suggest that variations in discharge in this region are largely driven by both natural variability and the effects of global climate change. We furthermore posit that the links between atmospheric and hydrologic processes result from a combination of forcings that operate on different spatiotemporal scales.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AIPC.1531..868H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AIPC.1531..868H"><span>UV-radiation in the past: Reconstruction and long-term changes in Austria</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hadzimustafic, J.; Simic, S.; Fitzka, M.</p> <p>2013-05-01</p> <p>Series of daily erythemal UV-dose are reconstructed for the last 30 years of the 20th century in Austria and its changes during that period with respect to observed changes in total ozone and cloud cover discussed. The reconstruction method is based on the relationship between long-term global radiation and sunshine duration records and existing measurements of erythemal UV at several locations. Through comparison with different data sources efforts are made to assure high data quality for all input parameters. The results for reconstructed daily sums show high correlations (0.95-0.99) with observed values compared on a yearly and seasonal basis throughout the overlapping period 1998-2010. Assessed from the reconstructed data, long-term variability of erythemal UV daily dose for two time periods has been quantified (1977-1995, 1996-2010). Special emphasis is put on the investigation of changes in UV due to observed trends in clouds and sunshine duration in the Austrian Alpine regions during the last decades. The earlier period shows significant changes between +4.1 %/dec and +6.9 %/dec at six stations in Austria, mainly due to significant decreases in total ozone column of up to -3.7 %/dec. Positive significant trends of around +2%/dec are found in cloud and aerosol modification factors at most of stations along with observed positive trends in sunshine duration, being statistically significant at eastern and southern stations. In spite of ozone layer recovery since the mid 1990s, the latter period does not reveal any statistically significant changes in erythemal UV irradiation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21700321','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21700321"><span>A model approach to assess the long-term trends of indirect photochemistry in lake water. The case of Lake Maggiore (NW Italy).</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Minella, Marco; Rogora, Michela; Vione, Davide; Maurino, Valter; Minero, Claudio</p> <p>2011-08-15</p> <p>A model-based approach is here developed and applied to predict the long-term trends of indirect photochemical processes in the surface layer (5m water depth) of Lake Maggiore, NW Italy. For this lake, time series of the main parameters of photochemical importance that cover almost two decades are available. As a way to assess the relevant photochemical reactions, the modelled steady-state concentrations of important photogenerated transients ((•)OH, ³CDOM* and CO₃(-•)) were taken into account. A multivariate analysis approach was adopted to have an overview of the system, to emphasise relationships among chemical, photochemical and seasonal variables, and to highlight annual and long-term trends. Over the considered time period, because of the decrease of the dissolved organic carbon (DOC) content of water and of the increase of alkalinity, a significant increase is predicted for the steady-state concentrations of the radicals (•)OH and CO₃(-•). Therefore, the photochemical degradation processes that involve the two radical species would be enhanced. Another issue of potential photochemical importance is related to the winter maxima of nitrate (a photochemical (•)OH source) and the summer maxima of DOC ((•)OH sink and ³CDOM* source) in the lake water under consideration. From the combination of sunlight irradiance and chemical composition data, one predicts that the processes involving (•)OH and CO₃(-•) would be most important in spring, while the reactions involving ³CDOM* would be most important in summer. Copyright © 2011 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ESDD....6..579H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ESDD....6..579H"><span>Prevailing climatic trends and runoff response from Hindukush-Karakoram-Himalaya, upper Indus basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hasson, S.; Böhner, J.; Lucarini, V.</p> <p>2015-03-01</p> <p>Largely depending on meltwater from the Hindukush-Karakoram-Himalaya, withdrawals from the upper Indus basin (UIB) contribute to half of the surface water availability in Pakistan, indispensable for agricultural production systems, industrial and domestic use and hydropower generation. Despite such importance, a comprehensive assessment of prevailing state of relevant climatic variables determining the water availability is largely missing. Against this background, we present a comprehensive hydro-climatic trend analysis over the UIB, including for the first time observations from high-altitude automated weather stations. We analyze trends in maximum, minimum and mean temperatures (Tx, Tn, and Tavg, respectively), diurnal temperature range (DTR) and precipitation from 18 stations (1250-4500 m a.s.l.) for their overlapping period of record (1995-2012), and separately, from six stations of their long term record (1961-2012). We apply Mann-Kendall test on serially independent time series to assess existence of a trend while true slope is estimated using Sen's slope method. Further, we statistically assess the spatial scale (field) significance of local climatic trends within ten identified sub-regions of UIB and analyze whether the spatially significant (field significant) climatic trends qualitatively agree with a trend in discharge out of corresponding sub-region. Over the recent period (1995-2012), we find a well agreed and mostly field significant cooling (warming) during monsoon season i.e. July-October (March-May and November), which is higher in magnitude relative to long term trends (1961-2012). We also find general cooling in Tx and a mixed response in Tavg during the winter season and a year round decrease in DTR, which are in direct contrast to their long term trends. The observed decrease in DTR is stronger and more significant at high altitude stations (above 2200 m a.s.l.), and mostly due to higher cooling in Tx than in Tn. Moreover, we find a field significant decrease (increase) in late-monsoonal precipitation for lower (higher) latitudinal regions of Himalayas (Karakoram and Hindukush), whereas an increase in winter precipitation for Hindukush, western- and whole Karakoram, UIB-Central, UIB-West, UIB-West-upper and whole UIB regions. We find a spring warming (field significant in March) and drying (except for Karakoram and its sub-regions), and subsequent rise in early-melt season flows. Such early melt response together with effective cooling during monsoon period subsequently resulted in a substantial drop (weaker increase) in discharge out of higher (lower) latitudinal regions (Himalaya and UIB-West-lower) during late-melt season, particularly during July. These discharge tendencies qualitatively differ to their long term trends for all regions, except for UIB-West-upper, western-Karakorum and Astore. The observed hydroclimatic trends, being driven by certain changes in the monsoonal system and westerly disturbances, indicate dominance (suppression) of nival (glacial) runoff regime, altering substantially the overall hydrology of UIB in future. These findings largely contribute to address the hydroclimatic explanation of the "Karakoram Anomaly".</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A11O..08C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A11O..08C"><span>Multidecadal variations of solar radiation reaching the surface and the role of aerosol direct radiative effects</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chin, M.; Diehl, T. L.; Bian, H.; Yu, H.; Kucsera, T. L.; Wild, M., Sr.; Hakuba, M. Z.; Qian, Y.; Stackhouse, P. W., Jr.; Pinker, R. T.; Zhang, Y.; Kato, S.; Loeb, N. G.; Kinne, S.; Streets, D. G.</p> <p>2017-12-01</p> <p>Incoming solar radiation drives the Earth's climate system. Long-term surface observations of the solar radiation reaching the surface (RSFC) have shown decreasing or increasing trends, often referred to as solar "dimming" or "brightening", in many regions of the world in the past several decades. Such long-term variation of RSFC mostly reflects the change of the solar-attenuation components within the atmosphere. Anthropogenic emissions of aerosols and precursor gases have changed significantly in the past decades with 50-80% reduction in North America and Europe but an increase of similar magnitude in East and South Asia since 1980, mirroring the change in RSFC over those regions. This has led to suggestions that aerosols play a critical role in determining RSFC trends. This work is to assess the role of direct radiative effects of aerosols on the solar "dimming" and "brightening" trends with modeling studies. First, we will show the trends of aerosol optical depth (AOD) and aerosol surface concentrations in different regions from 1980 to 2009 with remote sensing and in-situ data as well as model simulations, and attribute those changes to anthropogenic or natural sources. We will then show the trends of RSFC from the model and compare the results with observations from the surface networks and satellite-based products. Furthermore, we will use the GOCART model to attribute the "dimming/ brightening" trends to the changes of aerosols through the direct radiative effects. Finally, we will discuss the way forward to understand the aerosol effects on RSFC (as well as on other climate variables) through aerosol-cloud-radiation interactions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018HESS...22.2921F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018HESS...22.2921F"><span>Dendrohydrology and water resources management in south-central Chile: lessons from the Río Imperial streamflow reconstruction</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fernández, Alfonso; Muñoz, Ariel; González-Reyes, Álvaro; Aguilera-Betti, Isabella; Toledo, Isadora; Puchi, Paulina; Sauchyn, David; Crespo, Sebastián; Frene, Cristian; Mundo, Ignacio; González, Mauro; Vignola, Raffaele</p> <p>2018-05-01</p> <p>Streamflow in south-central Chile (SCC, ˜ 37-42° S) is vital for agriculture, forestry production, hydroelectricity, and human consumption. Recent drought episodes have generated hydrological deficits with damaging effects on these activities. This region is projected to undergo major reductions in water availability, concomitant with projected increases in water demand. However, the lack of long-term records hampers the development of accurate estimations of natural variability and trends. In order to provide more information on long-term streamflow variability and trends in SCC, here we report findings of an analysis of instrumental records and a tree-ring reconstruction of the summer streamflow of the Río Imperial ( ˜ 37° 40' S-38° 50' S). This is the first reconstruction in Chile targeted at this season. Results from the instrumental streamflow record ( ˜ 1940 onwards) indicated that the hydrological regime is fundamentally pluvial with a small snowmelt contribution during spring, and evidenced a decreasing trend, both for the summer and the full annual record. The reconstruction showed that streamflow below the average characterized the post-1980 period, with more frequent, but not more intense, drought episodes. We additionally found that the recent positive phase of the Southern Annular Mode has significantly influenced streamflow. These findings agree with previous studies, suggesting a robust regional signal and a shift to a new hydrological scenario. In this paper, we also discuss implications of these results for water managers and stakeholders; we provide rationale and examples that support the need for the incorporation of tree-ring reconstructions into water resources management.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29155862','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29155862"><span>A multi-paradigm framework to assess the impacts of climate change on end-use energy demand.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nateghi, Roshanak; Mukherjee, Sayanti</p> <p>2017-01-01</p> <p>Projecting the long-term trends in energy demand is an increasingly complex endeavor due to the uncertain emerging changes in factors such as climate and policy. The existing energy-economy paradigms used to characterize the long-term trends in the energy sector do not adequately account for climate variability and change. In this paper, we propose a multi-paradigm framework for estimating the climate sensitivity of end-use energy demand that can easily be integrated with the existing energy-economy models. To illustrate the applicability of our proposed framework, we used the energy demand and climate data in the state of Indiana to train a Bayesian predictive model. We then leveraged the end-use demand trends as well as downscaled future climate scenarios to generate probabilistic estimates of the future end-use demand for space cooling, space heating and water heating, at the individual household and building level, in the residential and commercial sectors. Our results indicated that the residential load is much more sensitive to climate variability and change than the commercial load. Moreover, since the largest fraction of the residential energy demand in Indiana is attributed to heating, future warming scenarios could lead to reduced end-use demand due to lower space heating and water heating needs. In the commercial sector, the overall energy demand is expected to increase under the future warming scenarios. This is because the increased cooling load during hotter summer months will likely outpace the reduced heating load during the more temperate winter months.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5695769','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5695769"><span>A multi-paradigm framework to assess the impacts of climate change on end-use energy demand</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Nateghi, Roshanak</p> <p>2017-01-01</p> <p>Projecting the long-term trends in energy demand is an increasingly complex endeavor due to the uncertain emerging changes in factors such as climate and policy. The existing energy-economy paradigms used to characterize the long-term trends in the energy sector do not adequately account for climate variability and change. In this paper, we propose a multi-paradigm framework for estimating the climate sensitivity of end-use energy demand that can easily be integrated with the existing energy-economy models. To illustrate the applicability of our proposed framework, we used the energy demand and climate data in the state of Indiana to train a Bayesian predictive model. We then leveraged the end-use demand trends as well as downscaled future climate scenarios to generate probabilistic estimates of the future end-use demand for space cooling, space heating and water heating, at the individual household and building level, in the residential and commercial sectors. Our results indicated that the residential load is much more sensitive to climate variability and change than the commercial load. Moreover, since the largest fraction of the residential energy demand in Indiana is attributed to heating, future warming scenarios could lead to reduced end-use demand due to lower space heating and water heating needs. In the commercial sector, the overall energy demand is expected to increase under the future warming scenarios. This is because the increased cooling load during hotter summer months will likely outpace the reduced heating load during the more temperate winter months. PMID:29155862</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUSMGC24A..02C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUSMGC24A..02C"><span>Long term monitoring system integrated in an elevational gradient in NW Argentina</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carilla, J.; Malizia, A.; Osinaga, O.; Blundo, C.; Grau, R.; Malizia, L.; Aráoz, E.</p> <p>2013-05-01</p> <p>Ecological trends and ranges of variability are poorly known in the tropical and subtropical Andes. Long term studies are powerful tools to detect the response of vegetation dynamics, biodiversity and hydrological cycle to these trends. We present a long term monitoring system in NW Argentinean mountains, including forest permanent plots at different elevations and high elevation grasslands, encompassing more than 3.000 m elevation range. Long term studies include: 1) 66 ha of mountain forest permanent plots along the Yungas elevational gradient from c. 400 to 2500 masl , and latitudinal gradient (22-28S) with 45 plots in mature forests and 28 in secondary forests originated in grazing, agriculture and selective logging. Some of these permanent plots have achieved 20 years of monitoring and all of them are included in the "Red de Bosques Andinos" a network created recently, together with c. 10 institutions and more than 130 (c. 120 ha) forest permanent plots from Argentina to Colombia Andes. 2) Two GLORIA (Global Observation Research Initiative in Alpine Environments) sites, above 4000 masl with more than 170 species recorded, including one re-measurement. This system is included in GLORIA network (www.gloria.ac.at) and in GLORIA Andes (http://www.condesan.org/gloria), and 3) more than 15 satellite monitored high Andean lakes and a wide extension of vegas (75800 ha in Argentinean puna). A digital database is being implemented to organize and provide access to the information generated by these three systems coordinated by the Instituto de Ecología Regional (http://www.iecologia.com.ar). These monitoring data are analyzed together with instrumental and dendrochronological data to describe the dynamics of these ecosystems over an area of 20 million hectares distributed between 22 and 28°S. Some of the most significant results to date include: 1) secondary mountain forests are expanding over grasslands and agriculture lands, and tend to converge toward mature forest composition over time, despite different previous land use. Floristic changes are also reflected in structural changes, showing an increasing trend in biomass in the last 15 years for most of the plots. Exotic tree species are expanding their distribution (e.g. Ligustrum lucidum) and have a strong influence on the structure and dynamics of some secondary forests. 2) High Andean vegetation diversity decrease with altitude, while several functional groups cover increase with temperature. 3) There is a clear association between lake fluctuations, ecosystem productivity and regional climatic patterns. The long term record provided by dendrochronology showed that plant productivity of the last decades is the lowest in the last 180 years, with a consistent drying trend in the last years. We are generating longer temporal series of meteorological data and biological ecosystems measurements; this will help to differentiate between the effect of climate change, land use change and natural ecosystems variability, to understand the way vegetation and ecosystems response to these changes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1411704M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1411704M"><span>Detecting the hydrological impacts of forest cover change in tropical mountain areas: need for detrending time series of rainfall and streamflow data.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Molina, A.; Vanacker, V.; Brisson, E.; Balthazar, V.</p> <p>2012-04-01</p> <p>Interactions between human activities and the physical environment have increasingly transformed the hydrological functioning of Andean ecosystems. In these human-modified landscapes, land use/-cover change may have a profound effect on riverine water and sediment fluxes. The hydrological impacts of land use/-cover change are diverse, as changes in vegetation affect the various components of the hydrological cycle including evapotranspiration, infiltration and surface runoff. Quantitative data for tropical mountain regions are scarce, as few long time series on rainfall, water discharge and land use are available. Furthermore, time series of rainfall and streamflow data in tropical mountains are often highly influenced by large inter- and intra-annual variability. In this paper, we analyse the hydrological response to complex forest cover change for a catchment of 280 km2 located in the Ecuadorian Andes. Forest cover change in the Pangor catchment was reconstructed based on airphotos (1963, 1977), LANDSAT TM (1991) and ETM+ data (2001, 2009). From 1963, natural vegetation was converted to agricultural land and pine plantations: forests decreased by a factor 2, and paramo decreased by 20 km2 between 1963 and 2009. For this catchment, there exists an exceptionally long record of rainfall and streamflow data that dates back from the '70s till now, but large variability in hydrometeorological data exists that is partly related to ENSO events. Given the nonstationary and nonlinear character of the ENSO-related changes in rainfall, we used the Hilbert-Huang transformation to detrend the time series of the river flow data from inter- and intra-annual fluctuations in rainfall. After applying adaptive data analysis based on empirical model decomposition techniques, it becomes apparent that the long-term trend in streamflow is different from the long-term trend in rainfall data. While the streamflow data show a long-term decrease in monthly flow, the rainfall data have a trend of increasing and then decreasing precipitation amounts. These results suggest that the land use changes had an important impact on the total water yield of the catchment. Interestingly, the effect of reforestation in the upper part of the catchment with its associated decrease in water yield seems to be dominant over the effect of deforestation in the lower part of the basin.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988PApGe.127..143K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988PApGe.127..143K"><span>Long-term variation of total ozone</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kane, R. P.</p> <p>1988-03-01</p> <p>The long-term variation of total ozone is studied for 1957 up to date for different latitude zones. The 3-year running averages show that, apart from a small portion showing parallelism with sunspot cycles, the trends in different latitude zones are dissimilar. In particular, where northern latitudes show a rising trend, the southern latitudes show an opposite (decreasing) trend. In the north-temperate group, Europe, North America and Asia show dissimilar trends. The longer data series (1932 ownards) for Arosa shows, besides a solar-cycle-dependent component, a steady level during 1932 1953 and a down-trend thereafter up to date. Very localised but long-lasting circulation patterns, different in different geographical regions, are indicated.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSPO33C..08D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSPO33C..08D"><span>Decadal trends of the upper ocean salinity in the tropical Indo-Pacific since mid-1990s</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>DU, Y.; Zhang, Y.</p> <p>2016-02-01</p> <p>A contrasting trend pattern of sea surface salinity (SSS) between the western tropical Pacific (WTP) and the southeastern tropical Indian Ocean (SETIO) is observed during 2004-2013, with significant salinity increase in the WTP and freshening in the SETIO. In this study, we show that increased precipitation around the Maritime Continent (MC), decreased precipitation in the western-central tropical Pacific, and ocean advection processes contribute to the salinity trends in the region. From a longer historical record, these salinity trends started in the mid-1990s, a few years before the Global Warming Hiatus from 1998 to present. The salinity trends are associated a strengthening trend of the Walker Circulation over the tropical Indo-Pacific, which have reversed the long-term salinity changes in the tropical Indo-Pacific as a consequence of global warming. Understanding decadal variations of SSS in the tropical Indo-Pacific will better inform on how the tropical hydrological cycle will be affected by the natural variability and a warming climate.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatSR...516050D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatSR...516050D"><span>Decadal trends of the upper ocean salinity in the tropical Indo-Pacific since mid-1990s</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Du, Yan; Zhang, Yuhong; Feng, Ming; Wang, Tianyu; Zhang, Ningning; Wijffels, Susan</p> <p>2015-11-01</p> <p>A contrasting trend pattern of sea surface salinity (SSS) between the western tropical Pacific (WTP) and the southeastern tropical Indian Ocean (SETIO) is observed during 2004-2013, with significant salinity increase in the WTP and freshening in the SETIO. In this study, we show that increased precipitation around the Maritime Continent (MC), decreased precipitation in the western-central tropical Pacific, and ocean advection processes contribute to the salinity trends in the region. From a longer historical record, these salinity trends started in the mid-1990s, a few years before the Global Warming Hiatus from 1998 to present. The salinity trends are associated a strengthening trend of the Walker Circulation over the tropical Indo-Pacific, which have reversed the long-term salinity changes in the tropical Indo-Pacific as a consequence of global warming. Understanding decadal variations of SSS in the tropical Indo-Pacific will better inform on how the tropical hydrological cycle will be affected by the natural variability and a warming climate.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4629206','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4629206"><span>Decadal trends of the upper ocean salinity in the tropical Indo-Pacific since mid-1990s</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Du, Yan; Zhang, Yuhong; Feng, Ming; Wang, Tianyu; Zhang, Ningning; Wijffels, Susan</p> <p>2015-01-01</p> <p>A contrasting trend pattern of sea surface salinity (SSS) between the western tropical Pacific (WTP) and the southeastern tropical Indian Ocean (SETIO) is observed during 2004–2013, with significant salinity increase in the WTP and freshening in the SETIO. In this study, we show that increased precipitation around the Maritime Continent (MC), decreased precipitation in the western-central tropical Pacific, and ocean advection processes contribute to the salinity trends in the region. From a longer historical record, these salinity trends started in the mid-1990s, a few years before the Global Warming Hiatus from 1998 to present. The salinity trends are associated a strengthening trend of the Walker Circulation over the tropical Indo-Pacific, which have reversed the long-term salinity changes in the tropical Indo-Pacific as a consequence of global warming. Understanding decadal variations of SSS in the tropical Indo-Pacific will better inform on how the tropical hydrological cycle will be affected by the natural variability and a warming climate. PMID:26522168</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26522168','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26522168"><span>Decadal trends of the upper ocean salinity in the tropical Indo-Pacific since mid-1990s.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Du, Yan; Zhang, Yuhong; Feng, Ming; Wang, Tianyu; Zhang, Ningning; Wijffels, Susan</p> <p>2015-11-02</p> <p>A contrasting trend pattern of sea surface salinity (SSS) between the western tropical Pacific (WTP) and the southeastern tropical Indian Ocean (SETIO) is observed during 2004-2013, with significant salinity increase in the WTP and freshening in the SETIO. In this study, we show that increased precipitation around the Maritime Continent (MC), decreased precipitation in the western-central tropical Pacific, and ocean advection processes contribute to the salinity trends in the region. From a longer historical record, these salinity trends started in the mid-1990s, a few years before the Global Warming Hiatus from 1998 to present. The salinity trends are associated a strengthening trend of the Walker Circulation over the tropical Indo-Pacific, which have reversed the long-term salinity changes in the tropical Indo-Pacific as a consequence of global warming. Understanding decadal variations of SSS in the tropical Indo-Pacific will better inform on how the tropical hydrological cycle will be affected by the natural variability and a warming climate.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ESD.....9..757N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ESD.....9..757N"><span>Recent trends in the frequency and duration of global floods</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Najibi, Nasser; Devineni, Naresh</p> <p>2018-06-01</p> <p>Frequency and duration of floods are analyzed using the global flood database of the Dartmouth Flood Observatory (DFO) to explore evidence of trends during 1985-2015 at global and latitudinal scales. Three classes of flood duration (i.e., short: 1-7, moderate: 8-20, and long: 21 days and above) are also considered for this analysis. The nonparametric Mann-Kendall trend analysis is used to evaluate three hypotheses addressing potential monotonic trends in the frequency of flood, moments of duration, and frequency of specific flood duration types. We also evaluated if trends could be related to large-scale atmospheric teleconnections using a generalized linear model framework. Results show that flood frequency and the tails of the flood duration (long duration) have increased at both the global and the latitudinal scales. In the tropics, floods have increased 4-fold since the 2000s. This increase is 2.5-fold in the north midlatitudes. However, much of the trend in frequency and duration of the floods can be placed within the long-term climate variability context since the Atlantic Multidecadal Oscillation, North Atlantic Oscillation, and Pacific Decadal Oscillation were the main atmospheric teleconnections explaining this trend. There is no monotonic trend in the frequency of short-duration floods across all the global and latitudinal scales. There is a significant increasing trend in the annual median of flood durations globally and each latitudinal belt, and this trend is not related to these teleconnections. While the DFO data come with a certain level of epistemic uncertainty due to imprecision in the estimation of floods, overall, the analysis provides insights for understanding the frequency and persistence in hydrologic extremes and how they relate to changes in the climate, organization of global and local dynamical systems, and country-scale socioeconomic factors.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/878','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/878"><span>Long-term growth trends of red spruce and fraser fir at Mt. Rogers, Virginia and Mt. Mitchell, North Carolina</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>J.C.G. Goelz; Thomas E. Burk; Shepard M. Zedaker</p> <p>1999-01-01</p> <p>Cross-sectional area growth and height growth of Fraser fir and red spruce trees growing in Virginia and North Carolina were analyzed to identify possible long-term growth trends. Cross-sectional area growth provided no evidence of growth decline. The individual discs were classified according to parameter estimates of the growth trend equation. The predominant pattern...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4536158','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4536158"><span>Sleep Variability in Adolescence is Associated with Altered Brain Development</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Telzer, Eva H.; Goldenberg, Diane; Fuligni, Andrew J.; Lieberman, Matthew D.; Galvan, Adriana</p> <p>2015-01-01</p> <p>Despite the known importance of sleep for brain development, and the sharp increase in poor sleep during adolescence, we know relatively little about how sleep impacts the developing brain. We present the first longitudinal study to examine how sleep during adolescence is associated with white matter integrity. We find that greater variability in sleep duration one year prior to a DTI scan is associated with lower white matter integrity above and beyond the effects of sleep duration, and variability in bedtime, whereas sleep variability a few months prior to the scan is not associated with white matter integrity. Thus, variability in sleep duration during adolescence may have long-term impairments on the developing brain. White matter integrity should be increasing during adolescence, and so sleep variability is directly at odds with normative developmental trends. PMID:26093368</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25482401','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25482401"><span>Detecting long-term growth trends using tree rings: a critical evaluation of methods.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Peters, Richard L; Groenendijk, Peter; Vlam, Mart; Zuidema, Pieter A</p> <p>2015-05-01</p> <p>Tree-ring analysis is often used to assess long-term trends in tree growth. A variety of growth-trend detection methods (GDMs) exist to disentangle age/size trends in growth from long-term growth changes. However, these detrending methods strongly differ in approach, with possible implications for their output. Here, we critically evaluate the consistency, sensitivity, reliability and accuracy of four most widely used GDMs: conservative detrending (CD) applies mathematical functions to correct for decreasing ring widths with age; basal area correction (BAC) transforms diameter into basal area growth; regional curve standardization (RCS) detrends individual tree-ring series using average age/size trends; and size class isolation (SCI) calculates growth trends within separate size classes. First, we evaluated whether these GDMs produce consistent results applied to an empirical tree-ring data set of Melia azedarach, a tropical tree species from Thailand. Three GDMs yielded similar results - a growth decline over time - but the widely used CD method did not detect any change. Second, we assessed the sensitivity (probability of correct growth-trend detection), reliability (100% minus probability of detecting false trends) and accuracy (whether the strength of imposed trends is correctly detected) of these GDMs, by applying them to simulated growth trajectories with different imposed trends: no trend, strong trends (-6% and +6% change per decade) and weak trends (-2%, +2%). All methods except CD, showed high sensitivity, reliability and accuracy to detect strong imposed trends. However, these were considerably lower in the weak or no-trend scenarios. BAC showed good sensitivity and accuracy, but low reliability, indicating uncertainty of trend detection using this method. Our study reveals that the choice of GDM influences results of growth-trend studies. We recommend applying multiple methods when analysing trends and encourage performing sensitivity and reliability analysis. Finally, we recommend SCI and RCS, as these methods showed highest reliability to detect long-term growth trends. © 2014 John Wiley & Sons Ltd.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.B41J..04G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.B41J..04G"><span>Long-term (10 year) trends in the chemistry of urban streams</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Groffman, P. M.; Band, L. E.; Belt, K. T.; Kaushal, S.; Fisher, G. T.</p> <p>2010-12-01</p> <p>Weekly sampling of eight streams in the Baltimore metropolitan area has been carried out since 1998 as part of the NSF funded Baltimore urban Long-Term Ecological Research (BES LTER) project. The BES watersheds include 100% forested and agricultural catchments and developed watersheds ranging from very low-density (<1% impervious surface) suburban watersheds serviced by septic systems to more dense (> 40% impervious surface) urban watersheds. Stream discharge is continuously monitored at these sites by the U.S. Geological Survey (USGS). Stream samples are collected weekly regardless of flow conditions (no bias towards storm versus baseflow) and analyzed for nitrate, total nitrogen (N), phosphate, total phosphorus (P), chloride and sulfate. Ten-year analysis of the BES long-term study sites reveals several interesting spatial and temporal patterns. For N, the highest concentrations were found in the agricultural and suburban watersheds, followed by the urban sites, and finally by the forested site. Organic N was most important as a proportion of total N in the urban and forested sites. Spatial patterns in P were more complex, with urban, suburban and agricultural sites having the highest values. Over the ten year record, many sites showed significant changes in N concentrations, but few sites showed consistent patterns in P. The patterns in N were quite variable however, with some sites showing striking increases, while others showed striking decreases. Most (7 of 8) sites showed a decrease in the proportion of organic N, the trend was significant at 4 of the sites. There were few trends in the proportion of organic P. Discharge was a significant driver of variation in N and P export at some (mostly smaller watersheds) sites, for some solutes, but was not an overwhelmingly important driver of temporal variation. Key factors driving long-term patterns include climate variation and efforts to improve urban stream water quality by municipal authorities.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016RAA....16...27S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016RAA....16...27S"><span>Long-term optical flux and colour variability in quasars</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sukanya, N.; Stalin, C. S.; Jeyakumar, S.; Praveen, D.; Dhani, Arnab; Damle, R.</p> <p>2016-02-01</p> <p>We have used optical V and R band observations from the Massive Compact Halo Object (MACHO) project on a sample of 59 quasars behind the Magellanic clouds to study their long term optical flux and colour variations. These quasars, lying in the redshift range of 0.2 < z < 2.8 and having apparent V band magnitudes between 16.6 and 20.1 mag, have observations ranging from 49 to 1353 epochs spanning over 7.5 yr with frequency of sampling between 2 to 10 days. All the quasars show variability during the observing period. The normalised excess variance (Fvar) in V and R bands are in the range 0.2% < FVvar < 1.6% and 0.1% < FRvar < 1.5% respectively. In a large fraction of the sources, Fvar is larger in the V band compared to the R band. From the z-transformed discrete cross-correlation function analysis, we find that there is no lag between the V and R band variations. Adopting the Markov Chain Monte Carlo (MCMC) approach, and properly taking into account the correlation between the errors in colours and magnitudes, it is found that the majority of sources show a bluer when brighter trend, while a minor fraction of quasars show the opposite behaviour. This is similar to the results obtained from another two independent algorithms, namely the weighted linear least squares fit (FITEXY) and the bivariate correlated errors and intrinsic scatter regression (BCES). However, the ordinary least squares (OLS) fit, normally used in the colour variability studies of quasars, indicates that all the quasars studied here show a bluer when brighter trend. It is therefore very clear that the OLS algorithm cannot be used for the study of colour variability in quasars.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1915061R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1915061R"><span>Analysis of the regional MiKlip decadal prediction system over Europe: skill, added value of regionalization, and ensemble size dependeny</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reyers, Mark; Moemken, Julia; Pinto, Joaquim; Feldmann, Hendrik; Kottmeier, Christoph; MiKlip Module-C Team</p> <p>2017-04-01</p> <p>Decadal climate predictions can provide a useful basis for decision making support systems for the public and private sectors. Several generations of decadal hindcasts and predictions have been generated throughout the German research program MiKlip. Together with the global climate predictions computed with MPI-ESM, the regional climate model (RCM) COSMO-CLM is used for regional downscaling by MiKlip Module-C. The RCMs provide climate information on spatial and temporal scales closer to the needs of potential users. In this study, two downscaled hindcast generations are analysed (named b0 and b1). The respective global generations are both initialized by nudging them towards different reanalysis anomaly fields. An ensemble of five starting years (1961, 1971, 1981, 1991, and 2001), each comprising ten ensemble members, is used for both generations in order to quantify the regional decadal prediction skill for precipitation and near-surface temperature and wind speed over Europe. All datasets (including hindcasts, observations, reanalysis, and historical MPI-ESM runs) are pre-processed in an analogue manner by (i) removing the long-term trend and (ii) re-gridding to a common grid. Our analysis shows that there is potential for skillful decadal predictions over Europe in the regional MiKlip ensemble, but the skill is not systematic and depends on the PRUDENCE region and the variable. Further, the differences between the two hindcast generations are mostly small. As we used detrended time series, the predictive skill found in our study can probably attributed to reasonable predictions of anomalies which are associated with the natural climate variability. In a sensitivity study, it is shown that the results may strongly change when the long-term trend is kept in the datasets, as here the skill of predicting the long-term trend (e.g. for temperature) also plays a major role. The regionalization of the global ensemble provides an added value for decadal predictions for some complex regions like the Mediterranean and Iberian Peninsula, while for other regions no systematic improvement is found. A clear dependence of the performance of the regional MiKlip system on the ensemble size is detected. For all variables in both hindcast generations, the skill increases when the ensemble is enlarged. The results indicate that a number of ten members is an appropriate ensemble size for decadal predictions over Europe.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMEP23B0961W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMEP23B0961W"><span>How climate and weather affect the erosion risk in the northern Gulf of Mexico</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wahl, T.; Plant, N. G.</p> <p>2015-12-01</p> <p>Oceanographic variables such as mean sea level, tides, storm surges, and waves are drivers of erosion, and they act on different time scales ranging from hours (associated with weather) to seasonal and decadal variations and trends (associated with climate). Here we explore how the related sea-state conditions affect the erosion risk in the northern Gulf of Mexico for past and future climate scenarios. From the climate perspective we find that long-term trends in the relevant variables have caused an increase of ~30% in the erosion risk since the 1980s; at least half of this increase was due to changes in the wave climate. In the next decades, sea level rise will likely become the dominating driver and may, in combination with ongoing changes in the wave climate (and depending on the emission scenario), escalate the erosion risk by up to 300% over the next 30 years. We also find significant changes in the seasonal cycles of sea level and significant wave height, which have in combination caused a considerable increase of the erosion risk in summer and decrease in winter (superimposed onto the long-term trends). The influence of weather is assessed with a copula-based multivariate sea storm model in a Monte-Carlo framework; i.e. we simulate hundreds of thousands of artificial but physically consistent sea-state conditions to quantify how different our understanding of the present day erosion risk would be if we had seen more or less extreme combinations of the different sea-state parameters over the last three decades. We find, for example, that total water levels (tide + surge + wave run-up) associated with 100-year return periods may be underestimated by up to 30% and that the average number of impact hours - when total water levels exceeded the height of the dune toe (collision) or dune crest (overwash) - could have been up to 50% higher than what we inferred based on the actually observed oceanographic conditions. Assessing erosion risk in such a probabilistic way while accounting for non-stationarity due to climate variability and change can help decision makers and planners to implement improved monitoring and adaptation strategies for long-term sustainability of the coastline and barrier islands.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.8892W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.8892W"><span>Erosion risk in the northern Gulf of Mexico - the effects of climate and weather</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wahl, Thomas; Plant, Nathaniel G.; Long, Joseph W.</p> <p>2016-04-01</p> <p>Oceanographic variables such as mean sea level, tides, storm surges, and waves are drivers of erosion, and they act on different time scales ranging from hours (associated with weather) to seasonal and decadal variations and trends (associated with climate). Here we explore how the related sea-state conditions affect the erosion risk in the northern Gulf of Mexico for past and future climate scenarios. From the climate perspective we find that long-term trends in the relevant variables have caused an increase of ~30% in the erosion risk since the 1980s; at least half of this increase was due to changes in the wave climate. In the next decades, sea level rise will likely become the dominating driver and may, in combination with ongoing changes in the wave climate (and depending on the emission scenario), escalate the erosion risk by up to 300% over the next 30 years. We also find significant changes in the seasonal cycles of sea level and significant wave height, which have in combination caused a considerable increase of the erosion risk in summer and decrease in winter (superimposed onto the long-term trends). The influence of weather is assessed with a copula-based multivariate sea storm model in a Monte-Carlo framework; i.e. we simulate hundreds of thousands of artificial but physically consistent sea-state conditions to quantify how different our understanding of the present day erosion risk would be if we had seen more or less extreme combinations of the different sea-state parameters over the last three decades. We find, for example, that total water levels (tide + surge + wave run-up) associated with 100-year return periods may be underestimated by up to 30% and that the average number of impact hours - when total water levels exceeded the height of the dune toe (collision) or dune crest (overwash) - could have been up to 50% higher than what we inferred based on the actually observed oceanographic conditions. Assessing erosion risk in such a probabilistic way while accounting for non-stationarity due to climate variability and change can help decision makers and planners to implement improved monitoring and adaptation strategies for long-term sustainability of the coastline and barrier islands.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A33G0323T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A33G0323T"><span>Development of A Dust Climate Indicator for the US National Climate Assessment</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tong, D.; Wang, J. X. L.; Gill, T. E.; Van Pelt, S.; Kim, D.</p> <p>2016-12-01</p> <p>Dust activity is a relatively simple but practical indicator to document the response of dryland ecosystems to climate change, making it an integral part of the National Climate Assessment (NCA). We present here a multi-agency collaboration that aims at developing a suite of dust climate indicators to document and monitor the long-term variability and trend of dust storm activity in the western United States. Recent dust observations have revealed rapid intensification of dust storm activity in the western United States. This trend is also closely correlated with a rapid increase in dust deposition in rainwater and "valley fever" hospitalization in southwestern states. It remains unclear, however, if such a trend, when enhanced by predicted warming and rainfall oscillation in the Southwest, will result in irreversible environmental development such as desertification or even another "Dust Bowl". Based on continuous ground aerosol monitoring, we have reconstructed a long-term dust storm climatology in the western United States. We report here direct evidence of rapid intensification of dust storm activity over US deserts in the past decades (1990 to 2013), in contrast to the decreasing trends in Asia and Africa. The US trend is spatially and temporally correlated with incidences of valley fever, an infectious disease caused by soil-dwelling fungus that has increased eight-fold in the past decade. We further investigate the linkage between dust variations and possible climate drivers and find that the regional dust trends are likely driven by large-scale variations of sea surface temperature in the Pacific Ocean, with the strongest correlation with the Pacific Decadal Oscillation (PDO). Future study will explore the link between the temporal and spatial trends of increase in dustiness and vegetation change in southwestern semi-arid and arid ecosystems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMGC43B0712L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMGC43B0712L"><span>West African warming: Investigating Temperature Trends and their relation between Precipitation Trends over West African Sahel.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>LY, M., Jr.</p> <p>2014-12-01</p> <p>It is now admitted that the West African region faces a lot of constraints due to the comprehensiveness of the high climate variability and potential climate change. This is mainly due to the lack of a large number of datasets and long-term records as summarized in the in the IPCC reports. This paper aims to provide improved knowledge and evidence on current and future climate conditions, for better manage climate variability over seasons and from year to year and strengthen the capacity to adapt to future climate change. In this regards, we analyse the evolution of some extreme temperature and precipitation indices over a large area of West Africa. Prior results show a general warming trend at individual stations throughout the region during the period from 1960 to 2010, namely negative trends in the number of cool nights, and positive trends in the number of warm days and length of warm spells. Trends in rainfall-related indices are not as uniform as the ones in temperatures, rather they display marked multi-decadal variability, as expected. To refine analyses of temperature variations and their relation to precipitation we investigated on cluster analysis aimed at distinguishing different sub-regions, such as continental and coastal, and relevant seasons, such as wet, dry/cold and dry warm. This will contribute to significantly lower uncertainties by developing better and more tailored temperature and precipitation trends to inform the user communities on climate related risks, as well as enhance their resilience to food insecurity and other climate related disasters.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMNH51B1610G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMNH51B1610G"><span>Non-stationarity of extreme weather events in a changing climate - an application to long-term droughts in the US Southwest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grossmann, I.</p> <p>2013-12-01</p> <p>Return periods of many extreme weather events are not stationary over time, given increasing risks due to global warming and multidecadal variability resulting from large scale climate patterns. This is problematic as extreme weather events and long-term climate risks such as droughts are typically conceptualized via measures such as return periods that implicitly assume non-stationarity. I briefly review these problems and present an application to the non-stationarity of droughts in the US Southwest. The US Southwest relies on annual precipitation maxima during winter and the North American Monsoon (NAM), both of which vary with large-scale climate patterns, in particular ENSO, the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). The latter two exhibit variability on longer (multi-decadal) time scales in addition to short-term variations. The region is also part of the subtropical belt projected to become more arid in a warming climate. The possible multidecadal impacts of the PDO on precipitation in the study region are analyzed with a focus on Arizona and New Mexico, using GPCC and CRU data since 1900. The projected impacts of the PDO on annual precipitation during the next three decades with GPCC data are similar in scale to the impacts of global warming on precipitation according to the A1B scenario and the CMIP2 multi-model means, while the combined impact of the PDO and AMO is about 19% larger. The effects according to the CRU dataset are about half as large as the projected global warming impacts. Given the magnitude of the projected impacts from both multidecadal variability and global warming, water management needs to explicitly incorporate both of these trends into long-term planning. Multi-decadal variability could be incorporated into the concept of return periods by presenting return periods as time-varying or as conditional on the respective 'phase' of relevant multidecadal patterns and on global warming. Problems in detecting the PDO signal and potential solutions are also discussed. We find that the long-term effect of the PDO can be more clearly separated from short-term variability by considering return periods of multi-year drought measures rather than return periods of simple drought measures that are more affected by short-term variations.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/1429681-electrification-energy-long-term-trends-opportunities','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1429681-electrification-energy-long-term-trends-opportunities"><span>The Electrification of Energy: Long-Term Trends and Opportunities</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Tsao, Jeffrey Y.; Fouquet, Roger; Schubert, E. Fred</p> <p></p> <p>Here, we present and analyze three powerful long-term historical trends in energy, particularly electrical energy, as well as the opportunities and challenges associated with these trends. The first trend is from a world containing a diversity of energy currencies to one whose predominant currency is electricity, driven by electricity’s transportability, exchangeability, and steadily decreasing cost. The second trend is from electricity generated from a diversity of sources to electricity generated predominantly by free-fuel sources, driven by their steadily decreasing cost and long-term abundance. These trends necessitate a just-emerging third trend: from a grid in which electricity is transported uni-directionally, tradedmore » at near-static prices, and consumed under direct human control; to a grid in which electricity is transported bi-directionally, traded at dynamic prices, and consumed under human-tailored agential control. Early acceptance and appreciation of these trends will accelerate their remaking of humanity’s energy landscape into one in which energy is much more affordable, abundant and efficiently deployed than it is today; with major economic, geo-political, and environmental benefits to human society.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=310844','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=310844"><span>Long-term trends in climate and hydrology in an agricultural, headwater watershed of central Pennsylvania, USA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Strategies to mitigate agricultural runoff must consider long-term changes in climate. We investigated temperature, precipitation and runoff trends over roughly four decades of monitoring an agricultural watershed in east central Pennsylvania (1968-2012). Temperature data confirmed significant expan...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=341230&Lab=NHEERL&keyword=energy&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=341230&Lab=NHEERL&keyword=energy&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>Long-term trends in fire behavior and changes in population at risk</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Long-term trends in fire behavior and changes in population at risk Rappold AG, Peterson GC, US EPA Matt Jolly, USFS Air pollution regulations and technological advances have successfully reduced emissions of air pollutants from many anthropogenic sources in recent decades. Duri...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.pca.state.mn.us/index.php/view-document.html?gid=19844','USGSPUBS'); return false;" href="http://www.pca.state.mn.us/index.php/view-document.html?gid=19844"><span>Nitrate Trends in Minnesota Rivers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wall, Dave; Christopherson, Dave; Lorenz, Dave; Martin, Gary</p> <p>2013-01-01</p> <p>The objective of this study was to assess long-term trends (30 to 35 years) of flow-adjusted concentrations of nitrite+nitrate-N (hereinafter referred to as nitrate) in a way that would allow us to discern changing trends. Recognizing that these trends are commonly different from one river to another river and from one part of the state to another, our objective was to examine as many river monitoring sites across the state as possible for which sufficient long term streamflow and concentration data were available.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JSAES..80..340R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JSAES..80..340R"><span>Suspended sediment load in northwestern South America (Colombia): A new view on variability and fluxes into the Caribbean Sea</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Restrepo López, Juan Camilo; Orejarena R, Andrés F.; Torregroza, Ana Carolina</p> <p>2017-12-01</p> <p>Monthly averaged suspended sediment load data from seven rivers in northern Colombia (Caribbean alluvial plain) draining into the Caribbean Sea were analyzed to quantify magnitudes, estimate long-term trends, and evaluate variability patterns of suspended sediment load. Collectively these rivers deliver an average of around 146.3 × 106 t yr-1 of suspended sediments to the Colombian Caribbean coast. The largest sediment supply is provided by the Magdalena River, with a mean suspended sediment load of 142.6 × 106 t yr-1, or 38% of the total fluvial discharge estimated for the whole Caribbean littoral zone. Between 2000 and 2010, the annual suspended sediment load of these rivers increased by as much as 36%. Wavelet spectral analyses identified periods of intense variability between 1987-1990 and 1994-2002, where major oscillation processes appeared simultaneously. The semi-annual, annual and quasi-decadal bands are the main factors controlling suspended sediment load variability in fluvial systems, whereas the quasi-biennial and interannual bands constitute second-order sources of variability. The climatic and oceanographic drivers of the oscillations identified through wavelet spectral analyses define a signal of medium-long-term variability for the suspended sediment load, while the physiographic and environmental characteristics of the basins determine their ability to magnify, attenuate or modify this signal.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015HESS...19.4201M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015HESS...19.4201M"><span>Multidecadal change in streamflow associated with anthropogenic disturbances in the tropical Andes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Molina, A.; Vanacker, V.; Brisson, E.; Mora, D.; Balthazar, V.</p> <p>2015-10-01</p> <p>Andean headwater catchments are an important source of freshwater for downstream water users. However, few long-term studies exist on the relative importance of climate change and direct anthropogenic perturbations on flow regimes in these catchments. In this paper, we assess change in streamflow based on long time series of hydrometeorological data (1974-2008) and land cover reconstructions (1963-2009) in the Pangor catchment (282 km2) located in the tropical Andes. Three main land cover change trajectories can be distinguished during the period 1963-2009: (1) expansion of agricultural land by an area equal to 14 % of the catchment area (or 39 km2) in 46 years' time, (2) deforestation of native forests by 11 % (or -31 km2) corresponding to a mean rate of 67 ha yr-1, and (3) afforestation with exotic species in recent years by about 5 % (or 15 km2). Over the time period 1963-2009, about 50 % of the 64 km2 of native forests was cleared and converted to agricultural land. Given the strong temporal variability of precipitation and streamflow data related to El Niño-Southern Oscillation, we use empirical mode decomposition techniques to detrend the time series. The long-term increasing trend in rainfall is remarkably different from the observed changes in streamflow, which exhibit a decreasing trend. Hence, observed changes in streamflow are not the result of long-term change in precipitation but very likely result from anthropogenic disturbances associated with land cover change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28279939','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28279939"><span>Decadal and seasonal trends of nutrient concentration and export from highly managed coastal catchments.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wan, Yongshan; Wan, Lei; Li, Yuncong; Doering, Peter</p> <p>2017-05-15</p> <p>Understanding anthropogenic and hydro-climatic influences on nutrient concentrations and export from highly managed catchments often necessitates trend detection using long-term monitoring data. This study analyzed the temporal trend (1979-2014) of total nitrogen (TN) and total phosphorus (TP) concentrations and export from four adjacent coastal basins in south Florida where land and water resources are highly managed through an intricate canal network. The method of integrated seasonal-trend decomposition using LOESS (LOcally weighted regrESSion) was employed for trend detection. The results indicated that long-term trends in TN and TP concentrations (increasing/decreasing) varied with basins and nutrient species, reflecting the influence of basin specific land and water management practices. These long-term trends were intervened by short-term highs driven by high rainfall and discharges and lows associated with regional droughts. Seasonal variations in TP were more apparent than for TN. Nutrient export exhibited a chemostatic behavior for TN from all the basins, largely due to the biogenic nature of organic N associated with the ubiquity of organic materials in the managed canal network. Varying degrees of chemodynamic export was present for TP, reflecting complex biogeochemical responses to the legacy of long-term fertilization, low soil P holding capacity, and intensive stormwater management. The anthropogenic and hydro-climatic influences on nutrient concentration and export behavior had great implications in nutrient loading abatement strategies for aquatic ecosystem restoration of the downstream receiving waterbody. Published by Elsevier Ltd.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRA..123.4467Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRA..123.4467Z"><span>Comments on "Long-Term Variations of Exospheric Temperature Inferred From foF1 Observations: A Comparison to ISR Ti Trend Estimates" by Perrone and Mikhailov</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Shun-Rong; Holt, John M.; Erickson, Philip J.; Goncharenko, Larisa P.</p> <p>2018-05-01</p> <p>Perrone and Mikhailov (2017, https://doi.org/10.1002/2017JA024193) and Mikhailov et al. (2017, https://doi.org/10.1002/2017JA023909) have recently examined thermospheric and ionospheric long-term trends using a data set of four thermospheric parameters (Tex, [O], [N2], and [O2]) and solar EUV flux. These data were derived from one single ionospheric parameter, foF1, using a nonlinear fitting procedure involving a photochemical model for the F1 peak. The F1 peak is assumed at the transition height ht with the linear recombination for atomic oxygen ions being equal to the quadratic recombination for molecular ions. This procedure has a number of obvious problems that are not addressed or not sufficiently justified. The potentially large ambiguities and biases in derived parameters make them unsuitable for precise quantitative ionospheric and thermospheric long-term trend studies. Furthermore, we assert that Perrone and Mikhailov (2017, https://doi.org/10.1002/2017JA024193) conclusions regarding incoherent scatter radar (ISR) ion temperature analysis for long-term trend studies are incorrect and in particular are based on a misunderstanding of the nature of the incoherent scatter radar measurement process. Large ISR data sets remain a consistent and statistically robust method for determining long term secular plasma temperature trends.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29135965','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29135965"><span>Comparison of Ground-Based and Satellite-Derived Solar UV Index Levels at Six South African Sites.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cadet, Jean-Maurice; Bencherif, Hassan; Portafaix, Thierry; Lamy, Kévin; Ncongwane, Katlego; Coetzee, Gerrie J R; Wright, Caradee Y</p> <p>2017-11-14</p> <p>South Africa has been measuring the ground-based solar UV index for more than two decades at six sites to raise awareness about the impacts of the solar UV index on human health. This paper is an exploratory study based on comparison with satellite UV index measurements from the OMI/AURA experiment. Relative UV index differences between ground-based and satellite-derived data ranged from 0 to 45% depending on the site and year. Most of time, these differences appear in winter. Some ground-based stations' data had closer agreement with satellite-derived data. While the ground-based instruments are not intended for long-term trend analysis, they provide UV index information for public awareness instead, with some weak signs suggesting such long-term trends may exist in the ground-based data. The annual cycle, altitude, and latitude effects clearly appear in the UV index data measured in South Africa. This variability must be taken into account for the development of an excess solar UV exposure prevention strategy.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5708023','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5708023"><span>Comparison of Ground-Based and Satellite-Derived Solar UV Index Levels at Six South African Sites</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Cadet, Jean-Maurice; Bencherif, Hassan; Portafaix, Thierry; Lamy, Kévin; Ncongwane, Katlego; Coetzee, Gerrie J. R.; Wright, Caradee Y.</p> <p>2017-01-01</p> <p>South Africa has been measuring the ground-based solar UV index for more than two decades at six sites to raise awareness about the impacts of the solar UV index on human health. This paper is an exploratory study based on comparison with satellite UV index measurements from the OMI/AURA experiment. Relative UV index differences between ground-based and satellite-derived data ranged from 0 to 45% depending on the site and year. Most of time, these differences appear in winter. Some ground-based stations’ data had closer agreement with satellite-derived data. While the ground-based instruments are not intended for long-term trend analysis, they provide UV index information for public awareness instead, with some weak signs suggesting such long-term trends may exist in the ground-based data. The annual cycle, altitude, and latitude effects clearly appear in the UV index data measured in South Africa. This variability must be taken into account for the development of an excess solar UV exposure prevention strategy. PMID:29135965</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001PrOce..50..325B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001PrOce..50..325B"><span>Long-term change in the megabenthos of the Porcupine Abyssal Plain (NE Atlantic)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Billett, D. S. M.; Bett, B. J.; Rice, A. L.; Thurston, M. H.; Galéron, J.; Sibuet, M.; Wolff, G. A.</p> <p></p> <p>A radical change in the abundance of invertebrate megafauna on the Porcupine Abyssal Plain is reported over a period of 10 years (1989-1999). Actiniarians, annelids, pycnogonids, tunicates, ophiuroids and holothurians increased significantly in abundance. However, there was no significant change in wet weight biomass. Two holothurian species, Amperima rosea and Ellipinion molle, increased in abundance by more than two orders of magnitude. Samples from the Porcupine Abyssal Plain over a longer period (1977-1999) show that prior to 1996 these holothurian species were always a minor component of the megafauna. From 1996 to 1999 A. rosea was abundant over a wide area of the Porcupine Abyssal Plain indicating that the phenomenon was not a localised event. Several dominant holothurian species show a distinct trend in decreasing body size over the study period. The changes in megafauna abundance may be related to environmental forcing (food supply) rather than to localised stochastic population variations. Inter-annual variability and long-term trends in organic matter supply to the seabed may be responsible for the observed changes in abundance, species dominance and size distributions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/wsp/2307/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wsp/2307/report.pdf"><span>Analysis and interpretation of water-quality trends in major U.S. rivers, 1974-81</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Smith, Richard A.; Alexander, Richard B.; Wolman, M. Gordon</p> <p>1987-01-01</p> <p>Water-quality records from two nationwide sampling networks are now of sufficient length to permit nationally consistent analysis of long-term water-quality trends at more than 300 locations on major U.S. rivers. Observed trends in 24 water-quality measures for the period 1974--81 provide evidence of both improvement and deterioration in stream quality during a time of major changes in atmospheric and terrestrial influences on surface waters. Particularly noteworthy are widespread decreases in lead and fecal bacteria concentrations and widespread increases in nitrate, arsenic, and cadmium concentrations. Changes in municipal waste treatment, leaded-gasoline consumption, highway-salt use, and nitrogen-fertilizer application, and regionally variable trends in coal production and combustion during the period, appear to be reflected in water-quality changes. There is evidence that atmospheric deposition of a variety of substances has played a surprisingly large role in water-quality changes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.4468P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.4468P"><span>Long-term coastal measurements for large-scale climate trends characterization</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pomaro, Angela; Cavaleri, Luigi; Lionello, Piero</p> <p>2017-04-01</p> <p>Multi-decadal time-series of observational wave data beginning in the late 1970's are relatively rare. The present study refers to the analysis of the 37-year long directional wave time-series recorded between 1979 and 2015 at the CNR-ISMAR (Institute of Marine Sciences of the Italian National Research Council) "Acqua Alta" oceanographic research tower, located in the Northern Adriatic Sea, 15 km offshore the Venice lagoon, on 16 m depth. The extent of the time series allows to exploit its content not only for modelling purposes or short-term statistical analyses, but also at the climatological scale thanks to the peculiar meteorological and oceanographic aspects of the coastal area where this relevant infrastructure has been installed. We explore the dataset both to characterize the local average climate and its variability, and to detect the possible long-term trends that might be suggestive of, or emphasize, large scale circulation patterns and trends. Measured data are essential for the assessment, and often for the calibration, of model data, generally, if long enough, also the reference also for climate studies. By applying this analysis to an area well characterized from the meteorological point of view, we first assess the changes in time based on measured data, and then we compare them to the ones derived from the ERA-Interim regional simulation over the same area, thus showing the strong improvement that is still needed to get reliable climate models projections on coastal areas and the Mediterranean Region as a whole. Moreover, long term hindcast aiming at climatic considerations are well known for 1) underestimating, if their resolution is not high enough, the actual wave heights as well as for 2) being strongly affected by different conditions over time that are likely to introduce spurious trends of variable magnitude. In particular the different amount, in time, of assimilated data by the hindcast models, directly and indirectly affects the results, making it difficult, if not impossible, to distinguish the imposed effects from the climate signal itself, as demonstrated by Aarnes et al. (2015). From this point of view the problem is that long-term measured datasets are relatively unique, due to the cost and technical difficulty of maintaining fixed instrumental equipment over time, as well as of assuring the homogeneity and availability of the entire dataset. For this reason we are furthermore working on the publication of the quality controlled dataset to make it widely available for open-access research purposes. The analysis and homogenization of the original dataset has actually required a substantial part of the time spent on the study, because of the strong impact that the quality of the data may have on the final result. We consider this particularly relevant, especially when referring to coastal areas, where the lack of reliable satellite data makes it difficult to improve the model capability to resolve the local peculiar oceanographic processes. We describe in detail any step and procedure used in producing the data, including full descriptions of the experimental design, data acquisition assays, and any computational processing needed to support the technical quality of the dataset.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/43053','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/43053"><span>Effects of climate variability on forest hydrology and carbon sequestration on the Santee Experimental Forest in coastal South Carolina</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Zhaohua Dai; Carl C. Trettin; Devendra M. Amatya</p> <p>2013-01-01</p> <p>Long-term weather and hydrology data from the Santee Experimental Forest were used to assess trends in air temperature, precipitation, and the water balance in gauged watersheds over a 63-year period. Since 1946, the mean annual air temperature has increased at a rate of 0.19 °C per decade, a rate higher than the global mean for the same period. Total annual...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy..tmp..414D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy..tmp..414D"><span>Ocean heat content variability in an ensemble of twentieth century ocean reanalyses</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Boisséson, Eric; Balmaseda, Magdalena Alonso; Mayer, Michael</p> <p>2017-08-01</p> <p>This paper presents a ten-member ensemble of twentieth century Ocean ReAnalyses called ORA-20C. ORA-20C assimilates temperature and salinity profiles and is forced by the ECMWF twentieth century atmospheric reanalysis (ERA-20C) over the 1900-2010 period. This study attempts to identify robust signals of ocean heat content change in ORA-20C and detect contamination by model errors, initial condition uncertainty, surface fluxes and observing system changes. It is shown that ORA-20C trends and variability in the first part of the century result from the surface fluxes and model drift towards a warmer mean state and weak meridional overturning circulation. The impact of the observing system in correcting the mean state causes the deceleration of the warming trend and alters the long-term climate signal. The ensemble spread reflects the long-lasting memory of the initial conditions and the convergence of the system to a solution compatible with surface fluxes, the ocean model and observational constraints. Observations constrain the ocean heat uptake trend in the last decades of the twentieth century, which is similar to trend estimations from the post-satellite era. An ocean heat budget analysis attributes ORA-20C heat content changes to surface fluxes in the first part of the century. The heat flux variability reflects spurious signals stemming from ERA-20C surface fields, which in return result from changes in the atmospheric observing system. The influence of the temperature assimilation increments on the heat budget is growing with time. Increments control the most recent ocean heat uptake signals, highlighting imbalances in forced reanalysis systems in the ocean as well as in the atmosphere.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.1941V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.1941V"><span>The GCOS Reference Upper-Air Network (GRUAN)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vömel, H.; Berger, F. H.; Immler, F. J.; Seidel, D.; Thorne, P.</p> <p>2009-04-01</p> <p>While the global upper-air observing network has provided useful observations for operational weather forecasting for decades, its measurements lack the accuracy and long-term continuity needed for understanding climate change. Consequently, the scientific community faces uncertainty on such key issues as the trends of temperature in the upper troposphere and stratosphere or the variability and trends of stratospheric water vapour. To address these shortcomings, and to ensure that future climate records will be more useful than the records to date, the Global Climate Observing System (GCOS) program initiated the GCOS Reference Upper Air Network (GRUAN). GRUAN will be a network of about 30-40 observatories with a representative sampling of geographic regions and surface types. These stations will provide upper-air reference observations of the essential climate variables, i.e. temperature, geopotential, humidity, wind, radiation and cloud properties using specialized radiosondes and complementary remote sensing profiling instrumentation. Long-term stability, quality assurance / quality control, and a detailed assessment of measurement uncertainties will be the key aspects of GRUAN observations. The network will not be globally complete but will serve to constrain and adjust data from more spatially comprehensive global observing systems including satellites and the current radiosonde networks. This paper outlines the scientific rationale for GRUAN, its role in the Global Earth Observation System of Systems, network requirements and likely instrumentation, management structure, current status and future plans.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5453561','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5453561"><span>Trends of vaccine-preventable diseases in Afghanistan from the Disease Early Warning System, 2009–2015</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mubarak, Mohammad Y.; Johnson, Laura E.; Porth, Julia M.; Yousif, Jenna E.; Boulton, Matthew L.</p> <p>2017-01-01</p> <p>Background Afghanistan’s public health system was neglected during decades of military and civil conflict, and trends in infectious disease occurrence remain poorly characterized. This study examines cyclical and long-term trends of six vaccine-preventable diseases: pneumonia, diarrhea, meningitis, typhoid, measles, and acute viral hepatitis. Methods Using weekly data collected between 2009 and 2015 through Afghanistan’s Disease Early Warning System, we calculated monthly case counts, and fit a Poisson regression with a Fourier transformation for seasonal cycles and dummy variables for year. Results We found the greatest incidence of diarrhea and typhoid in the summer, pneumonia in the winter, and measles in the late spring. Meningitis and acute viral hepatitis did not demonstrate substantial seasonality. Rates of pneumonia and diarrhea were constant across years whereas rates of meningitis, typhoid, and acute viral hepatitis decreased. Measles incidence increased in 2015. Conclusions Communicable disease reporting systems can guide public health operations–such as the implementation of new vaccines, and permit evaluation of health interventions. For example, measles supplementary immunization activities in Afghanistan have not slowed long-term transmission of the disease, but decreases in typhoid fever and acute viral hepatitis are probably tied to improvements in sanitation in the country. PMID:28570694</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26868836','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26868836"><span>Subtropical Potential Vorticity Intrusion Drives Increasing Tropospheric Ozone over the Tropical Central Pacific.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nath, Debashis; Chen, Wen; Graf, Hans-F; Lan, Xiaoqing; Gong, Hainan; Nath, Reshmita; Hu, Kaiming; Wang, Lin</p> <p>2016-02-12</p> <p>Drawn from multiple reanalysis datasets, an increasing trend and westward shift in the number of Potential Vorticity intrusion events over the Pacific are evident. The increased frequency can be linked to a long-term trend in upper tropospheric equatorial westerly wind and subtropical jets during boreal winter to spring. These may be resulting from anomalous warming and cooling over the western Pacific warm pool and the tropical eastern Pacific, respectively. The intrusions brought dry and ozone rich air of stratospheric origin deep into the tropics. In the tropical upper troposphere, interannual ozone variability is mainly related to convection associated with El Niño/Southern Oscillation. Zonal mean stratospheric overturning circulation organizes the transport of ozone rich air poleward and downward to the high and midlatitudes leading there to higher ozone concentration. In addition to these well described mechanisms, we observe a long-term increasing trend in ozone flux over the northern hemispheric outer tropical (10-25°N) central Pacific that results from equatorward transport and downward mixing from the midlatitude upper troposphere and lower stratosphere during PV intrusions. This increase in tropospheric ozone flux over the Pacific Ocean may affect the radiative processes and changes the budget of atmospheric hydroxyl radicals.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1980/0036/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1980/0036/report.pdf"><span>Water quality of the Neuse River, North Carolina : variability, pollution loads, and long-term trends</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Harned, Douglas A.</p> <p>1980-01-01</p> <p>A water-quality study of the Neuse River, N.C., based on data collected during 1956-77 at the U.S. Geological Survey stations at Clayton and Kinston, employs statistical trend analysis techniques that provide a framework for river quality assessment. Overall, water-quality of the Neuse River is satisfactory for most uses. At Clayton, fecal coliform bacteria and nutrient levels are high, but algae and total-organic-carbon data indicate water-quality improvement in recent years, due probably to a new wastewater treatment plant located downstream from Raleigh, N.C. Pollution was determined by subtracting estimated natural loads of constituents from measured total loads. Pollution makes up approximately 50% of the total dissolved material transported by the Neuse. Two different data transformation methods allowed trends to be identified in constituent concentrations. The methods recomputed the concentrations as if they were determined at a constant discharge over the period of record. Although little change since 1956 can be seen in most constituents, large changes in some constituents, such as increases in potassium and sulfate, indicate that the water quality of the Neuse River has noticeably deteriorated. Increases in sulfate are probably largely due to increased long-term inputs of sulfur compounds from airborne pollutants. (USGS)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29195206','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29195206"><span>Effects of changing climate on European stream invertebrate communities: A long-term data analysis.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jourdan, Jonas; O'Hara, Robert B; Bottarin, Roberta; Huttunen, Kaisa-Leena; Kuemmerlen, Mathias; Monteith, Don; Muotka, Timo; Ozoliņš, Dāvis; Paavola, Riku; Pilotto, Francesca; Springe, Gunta; Skuja, Agnija; Sundermann, Andrea; Tonkin, Jonathan D; Haase, Peter</p> <p>2018-04-15</p> <p>Long-term observations on riverine benthic invertebrate communities enable assessments of the potential impacts of global change on stream ecosystems. Besides increasing average temperatures, many studies predict greater temperature extremes and intense precipitation events as a consequence of climate change. In this study we examined long-term observation data (10-32years) of 26 streams and rivers from four ecoregions in the European Long-Term Ecological Research (LTER) network, to investigate invertebrate community responses to changing climatic conditions. We used functional trait and multi-taxonomic analyses and combined examinations of general long-term changes in communities with detailed analyses of the impact of different climatic drivers (i.e., various temperature and precipitation variables) by focusing on the response of communities to climatic conditions of the previous year. Taxa and ecoregions differed substantially in their response to climate change conditions. We did not observe any trend of changes in total taxonomic richness or overall abundance over time or with increasing temperatures, which reflects a compensatory turnover in the composition of communities; sensitive Plecoptera decreased in response to warmer years and Ephemeroptera increased in northern regions. Invasive species increased with an increasing number of extreme days which also caused an apparent upstream community movement. The observed changes in functional feeding group diversity indicate that climate change may be associated with changes in trophic interactions within aquatic food webs. These findings highlight the vulnerability of riverine ecosystems to climate change and emphasize the need to further explore the interactive effects of climate change variables with other local stressors to develop appropriate conservation measures. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26618102','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26618102"><span>Approaches to Observe Anthropogenic Aerosol-Cloud Interactions.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Quaas, Johannes</p> <p></p> <p>Anthropogenic aerosol particles exert an-quantitatively very uncertain-effective radiative forcing due to aerosol-cloud interactions via an immediate altering of cloud albedo on the one hand and via rapid adjustments by alteration of cloud processes and by changes in thermodynamic profiles on the other hand. Large variability in cloud cover and properties and the therefore low signal-to-noise ratio for aerosol-induced perturbations hamper the identification of effects in observations. Six approaches are discussed as a means to isolate the impact of anthropogenic aerosol on clouds from natural cloud variability to estimate or constrain the effective forcing. These are (i) intentional cloud modification, (ii) ship tracks, (iii) differences between the hemispheres, (iv) trace gases, (v) weekly cycles and (vi) trends. Ship track analysis is recommendable for detailed process understanding, and the analysis of weekly cycles and long-term trends is most promising to derive estimates or constraints on the effective radiative forcing.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMOS43A2010A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMOS43A2010A"><span>Anthropogenic Influence on the Changes of the Subtropical Gyre Circulation in the South Pacific in the 20th Century</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Albrecht, F.; Pizarro, O.; Montecinos, A.</p> <p>2016-12-01</p> <p>The subtropical ocean gyre in the South Pacific is a large scale wind-driven ocean circulation, including the Peru-Chile Current, the westward South Equatorial Current, the East Australian Current, and the eastward South Pacific Current. Large scale ocean circulations play an essential role in the climate of the Earth over long and short term time scales.In the recent years a spin-up of this circulation has been recognized analyzing observations of sea level, temperature and salinity profiles, sea surface temperature and wind. Until now it is not clear whether this spin-up is decadal variability or whether it is a long-term trend introduced by anthropogenic forcing. This study aims to analyze whether and how anthropogenic forcing influences the position and the strength of the gyre in the 20th century. To determine that, yearly means of different variables of an ensemble of CMIP5 models are analyzed. The experiments 'historical' and 'historicalNat' are examined. The 'historical' experiment simulates the climate of the 20th century and the 'historicalNat' experiment covers the same time period, but only includes natural forcings. Comparing the outcomes of these two experiments is supposed to give information about the anthropogenic influence on the subtropical gyre of the South Pacific.The main variable we analyze is sea level change. This is directly related to the gyre circulation. The center of the gyre is characterized by a high pressure zone (high sea level) and the temporal and spatial variability of the sea level height field gives information about changes in the gyre circulation. The CMIP5 databank includes steric and dynamic sea level changes. Steric sea level, that is the contribution of temperature and salinity of the water, describes the major contribution to regional sea level change with respect to the global mean. Density changes contract or expand the water, which also changes the sea surface height. This does not only occur at the surface, but at all layers in the ocean. Sea level change thus integrates ocean variability throughout the depth of the ocean. Sea level simulations of the different experiments are compared using long-term trends, multi-year anomalies and EOF-Analysis. Changes in temperature and salinity in the deeper ocean are used to describe the development of the gyre below the surface.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1912539S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1912539S"><span>Analysis on variability and trend in Antarctic sea ice albedo between 1983 and 2009</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seo, Minji; Kim, Hyun-cheol; Choi, Sungwon; Lee, Kyeong-sang; Han, Kyung-soo</p> <p>2017-04-01</p> <p>Sea ice is key parameter in order to understand the cryosphere climate change. Several studies indicate the different trend of sea ice between Antarctica and Arctic. Albedo is important factor for understanding the energy budget and factors for observing of environment changes of Cryosphere such as South Pole, due to it mainly covered by ice and snow with high albedo value. In this study, we analyzed variability and trend of long-term sea ice albedo data to understand the changes of sea ice over Antarctica. In addiction, sea ice albedo researched the relationship with Antarctic oscillation in order to determine the atmospheric influence. We used the sea ice albedo data at The Satellite Application Facility on Climate Monitoring and Antarctic Oscillation data at NOAA Climate Prediction Center (CPC). We analyzed the annual trend in albedo using linear regression to understand the spatial and temporal tendency. Antarctic sea ice albedo has two spatial trend. Weddle sea / Ross sea sections represent a positive trend (0.26% ˜ 0.04% yr-1) and Bellingshausen Amundsen sea represents a negative trend (- 0.14 ˜ -0.25%yr-1). Moreover, we performed the correlation analysis between albedo and Antarctic oscillation. As a results, negative area indicate correlation coefficient of - 0.3639 and positive area indicates correlation coefficient of - 0.0741. Theses results sea ice albedo has regional trend according to ocean. Decreasing sea ice trend has negative relationship with Antarctic oscillation, its represent a possibility that sea ice influence atmospheric factor.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=310254&keyword=chlorophyll&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=310254&keyword=chlorophyll&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>Adaptation of a Weighted Regression Approach to Evaluate Water Quality Trends in an Estuary</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>To improve the description of long-term changes in water quality, we adapted a weighted regression approach to analyze a long-term water quality dataset from Tampa Bay, Florida. The weighted regression approach, originally developed to resolve pollutant transport trends in rivers...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=indian+AND+women&id=EJ893450','ERIC'); return false;" href="https://eric.ed.gov/?q=indian+AND+women&id=EJ893450"><span>Gender-Based Violence in India: Long-Term Trends</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Simister, John; Mehta, Parnika S.</p> <p>2010-01-01</p> <p>This article examines long-term trends in Indian society regarding domestic violence between husband and wife, and attitudes to such violence. This article analyzes crime data and uses data from several Indian household surveys: "Work Attitudes and Spending" surveys (1992 to 2007); "World Values Survey" (1990, 1995, 2001, and…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=310972&Lab=NHEERL&keyword=statistics&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=310972&Lab=NHEERL&keyword=statistics&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>Adaptation of a weighted regression approach to evaluate water quality trends in anestuary</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>To improve the description of long-term changes in water quality, a weighted regression approach developed to describe trends in pollutant transport in rivers was adapted to analyze a long-term water quality dataset from Tampa Bay, Florida. The weighted regression approach allows...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16741862','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16741862"><span>Zeitgeists and development trends in long-term care facility design.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Chia-Hui; Kuo, Nai-Wen</p> <p>2006-06-01</p> <p>Through literature analysis, in-depth interviews, and the application of the Delphi survey, this study explored long-term care resident priorities with regard to long-term care facility design in terms of both physical and psychological needs. This study further clarified changing trends in long-term care concepts; illustrated the impact that such changes are having on long-term care facility design; and summarized zeitgeists related to the architectural design of long-term care facilities. Results of our Delphi survey indicated the following top five priorities in long-term care facility design: (1) creating a home-like feeling; (2) adhering to Universal Design concepts; (3) providing well-defined private sleeping areas; (4) providing adequate social space; and (5) decentralizing residents' rooms into clusters. The three major zeitgeists related to long-term care facility design include: (1) modern long-term care facilities should abandon their traditional "hospital" image and gradually reposition facilities into homelike settings; (2) institution-based care for the elderly should be de-institutionalized under the concept of aging-in-place; and (3) living clusters, rather than traditional hospital-like wards, should be designed into long-term care facilities.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1514093W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1514093W"><span>Climate change impacts on rainfall extremes and urban drainage: state-of-the-art review</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Willems, Patrick; Olsson, Jonas; Arnbjerg-Nielsen, Karsten; Beecham, Simon; Pathirana, Assela; Bülow Gregersen, Ida; Madsen, Henrik; Nguyen, Van-Thanh-Van</p> <p>2013-04-01</p> <p>Under the umbrella of the IWA/IAHR Joint Committee on Urban Drainage, the International Working Group on Urban Rainfall (IGUR) has reviewed existing methodologies for the analysis of long-term historical and future trends in urban rainfall extremes and their effects on urban drainage systems, due to anthropogenic climate change. Current practises have several limitations and pitfalls, which are important to be considered by trend or climate change impact modellers and users of trend/impact results. The review considers the following aspects: Analysis of long-term historical trends due to anthropogenic climate change: influence of data limitation, instrumental or environmental changes, interannual variations and longer term climate oscillations on trend testing results. Analysis of long-term future trends due to anthropogenic climate change: by complementing empirical historical data with the results from physically-based climate models, dynamic downscaling to the urban scale by means of Limited Area Models (LAMs) including explicitly small-scale cloud processes; validation of RCM/GCM results for local conditions accounting for natural variability, limited length of the available time series, difference in spatial scales, and influence of climate oscillations; statistical downscaling methods combined with bias correction; uncertainties associated with the climate forcing scenarios, the climate models, the initial states and the statistical downscaling step; uncertainties in the impact models (e.g. runoff peak flows, flood or surcharge frequencies, and CSO frequencies and volumes), including the impacts of more extreme conditions than considered during impact model calibration and validation. Implications for urban drainage infrastructure design and management: upgrading of the urban drainage system as part of a program of routine and scheduled replacement and renewal of aging infrastructure; how to account for the uncertainties; flexible and sustainable solutions; adaptive approach that provides inherent flexibility and reversibility and avoids closing off options; importance of active learning. References: Willems, P., Olsson, J., Arnbjerg-Nielsen, K., Beecham, S., Pathirana, A., Bülow Gregersen, I., Madsen, H., Nguyen, V-T-V. (2012). Impacts of climate change on rainfall extremes and urban drainage. IWA Publishing, 252 p., Paperback Print ISBN 9781780401256; Ebook ISBN 9781780401263 Willems, P., Arnbjerg-Nielsen, K., Olsson, J., Nguyen, V.T.V. (2012), 'Climate change impact assessment on urban rainfall extremes and urban drainage: methods and shortcomings', Atmospheric Research, 103, 106-118</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/fs116-00/fs116-00.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/fs116-00/fs116-00.pdf"><span>Effects of climate variability and human activities on Chesapeake Bay and the implications for ecosystem restoration</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Cronin, Thomas M.; Willard, Debra A.; Phillips, Scott</p> <p>2000-01-01</p> <p>Chesapeake Bay, the Nation’s largest and most productive estuary (fig. 1), faces complex environmental issues related to nutrients and oxygen, turbidity and sedimentation, toxic dinoflagellates, sea-level rise, and coastal erosion. The Chesapeake Bay Program (CBP) is a partnership among the Chesapeake Bay Commission, the Federal Government, the District of Columbia, and the States of Maryland, Virginia, and Pennsylvania. The CBP is working to preserve, restore, and protect the bay’s living resources, vital habitats, and water quality, to protect human health, and to promote sound land-use policies in the watershed. The CBP began to set restoration goals for the ecosystem in the mid-1980’s and is now refining current goals and setting new ones as part of a new bay agreement— Chesapeake 2000. As the CBP sets restoration goals for the next 10–20 years, it will be critical to understand the long-term changes of the bay ecosystem due to climate variability and the influence of past and future human activities.For the past 4 years, the U.S. Geological Survey (USGS) has been engaged in research designed to provide objective scientific answers to questions about long-term changes in the bay ecosystem: What paleoecological and geochemical methods are best for documenting trends in the bay ecosystem?How does climate variability, including drought, affect the bay?What are historical trends in dissolved oxygen?What is the relationship between sedimentation and water clarity, and what is the effect of turbidity on living resources?How have past land-use changes affected bay habitats and living resources?</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JSR...120...24H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JSR...120...24H"><span>Population regulation in a changing environment: Long-term changes in growth, condition and survival of sprat, Sprattus sprattus L. in the Bristol Channel, UK</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Henderson, Peter A.; Henderson, Rowena C.</p> <p>2017-02-01</p> <p>Sprat, Sprattus sprattus, is the dominant pelagic species in British inshore and estuarine waters. Within the Bristol Channel the population is almost totally composed of fish < 3 years old with the adults overwintering in Bridgwater Bay. Sprat follow regular seasonal migrations and occasionally form huge aggregations which together generate considerable between sample variability. Using a 36-year monthly time series collected in the Bristol Channel since 1980, together with two periods of intensive daily and weekly sampling, sprat growth is shown to have declined almost linearly over the last 36 years coincident with increasing late summer-autumn seawater temperatures. Longevity has also declined, with age 3 + sprat > 140 mm standard length lost to the population by 1999. Further, adult condition, measured as the average weight of a 103 mm standard length adult, declined rapidly from 13.7 g in 2007 to 9 g in 2011. Despite these changes, which would have reduced age-specific fecundity, a sign-rank test showed abundance of adult sprat has shown no long-term trend and Bulmer's test indicates density-dependent regulation is operating. While sprat recruitment is shown to be responding to the sunspot cycle, the North Atlantic Oscillation and sea water temperature, the impact of these variables on adult population density is damped because of density-dependent regulation. The result is that sprat respond to environmental change with large changes in their growth and condition, but the adult abundance is constrained and shows no long-term trend. Recruitment was modelled by combining a Ricker curve with terms for the response of sprat to solar activity, the North Atlantic Oscillation and spring temperature. It is shown that the stock-recruitment relationship does not form a simple curve, but is bounded within a region in which the upper and lower constraints are defined by environmental conditions. Within this bounded region the population trajectory under differing environmental regimes can be predicted.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AcPPB..40..175K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AcPPB..40..175K"><span>Structure and Evolution of the Foreign Exchange Networks</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kwapień, J.; Gworek, S.; Drożdż, S.</p> <p>2009-01-01</p> <p>We investigate topology and temporal evolution of the foreign currency exchange market viewed from a weighted network perspective. Based on exchange rates for a set of 46 currencies (including precious metals), we construct different representations of the FX network depending on a choice of the base currency. Our results show that the network structure is not stable in time, but there are main clusters of currencies, which persist for a long period of time despite the fact that their size and content are variable. We find a long-term trend in the network's evolution which affects the USD and EUR nodes. In all the network representations, the USD node gradually loses its centrality, while, on contrary, the EUR node has become slightly more central than it used to be in its early years. Despite this directional trend, the overall evolution of the network is noisy.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ERL....13c4026S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ERL....13c4026S"><span>Satellite view of seasonal greenness trends and controls in South Asia</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sarmah, Sangeeta; Jia, Gensuo; Zhang, Anzhi</p> <p>2018-03-01</p> <p>South Asia (SA) has been considered one of the most remarkable regions for changing vegetation greenness, accompanying its major expansion of agricultural activities, especially irrigated farming. The influence of the monsoon climate on the seasonal trends and anomalies of vegetation greenness is poorly understood in this area. Herein, we used the satellite-based Normalized Difference Vegetation Index (NDVI) to investigate various spatiotemporal patterns in vegetation activity during summer and winter monsoon (SM and WM) seasons and among irrigated croplands (IC), rainfed croplands (RC), and natural vegetation (NV) areas during 1982–2013. Seasonal NDVI variations with climatic factors (precipitation and temperature) and land use and cover changes (LUCC) have also been investigated. This study demonstrates that the seasonal dynamics of vegetation could improve the detailed understanding of vegetation productivity over the region. We found distinct greenness trends between two monsoon seasons and among the major land use/cover classes. Winter monsoons contributed greater variability to the overall vegetation dynamics of SA. Major greening occurred due to the increased productivity over irrigated croplands during the winter monsoon season; meanwhile, browning trends were prominent over NV areas during the same season. Maximum temperatures had been increasing tremendously during the WM season; however, the precipitation trend was not significant over SA. Both the climate variability and LUCC revealed coupled effects on the long term NDVI trends in NV areas, especially in the hilly regions, whereas anthropogenic activities (agricultural advancements) played a pivotal role in the rest of the area. Until now, advanced cultivation techniques have proven to be beneficial for the region in terms of the productivity of croplands. However, the crop productivity is at risk under climate change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.G21A0990B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.G21A0990B"><span>Secular Change and Inter-annual Variability of the Gulf Stream Position, 1993-2013, 70°-55°W</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bisagni, J. J.; Gangopadhyay, A.</p> <p>2016-12-01</p> <p>The Gulf Stream (GS) is the northeastward-flowing surface limb of the Atlantic Ocean meridional overturning circulation (AMOC) "conveyer belt" that flows towards Europe and the Nordic Seas. Changes in the GS position after its separation from the coast at Cape Hatteras, i.e., from 75°W to 50°W, may be key to understanding the AMOC, sea level variability and ecosystem behavior along the east coast of North America. In this study we compare secular change and inter-annual variability (IAV) of annual mean Gulf Stream North Wall (GSNW) position with equator-ward Labrador Current (LC) transport along the southwestern Grand Banks near 52° W using 21 years (1993-2013) of satellite altimeter data. Results at 70°, 65°, 60° and 55° W show a southward secular trend for the GSNW, decreasing to the west. IAV of de-trended GSNW position residuals also decreases to the west. The long-term secular trend of annual mean upper layer LC transport increases near 52° W. Furthermore, IAV of LC transport residuals near 52° W is significantly correlated with GSNW position residuals at 55° W at a lag of +1-year. Spectral analysis reveals inter-annual peaks at 5-7 years and 2-3 years for the North Atlantic Oscillation (NAO), GSNW (65°-55°W) and LC transport for 1993-2013. A volume calculation using the LC rms residual of +1.04 Sv near 52° W results in an estimated GSNW residual of 79 km, or 63% of the observed 125.6 km (1.13°) rms value at 55° W. A similar volume calculation using the positive long-term, upper-layer LC transport trend accounts for 68% of the observed southward shift of the GSNW over the 1993-2013 period. Our work provides observational evidence of direct interaction between the upper layers of the sub-polar and sub-tropical gyres within the North Atlantic over secular and inter-annual time scales as suggested by previous workers.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A21E2203J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A21E2203J"><span>Long-term variability of wind patterns at hub-height over Texas</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jung, J.; Jeon, W.; Choi, Y.; Souri, A.</p> <p>2017-12-01</p> <p>Wind energy is getting more attention because of its environmentally friendly attributes. Texas is a state with significant capacity and number of wind turbines. Wind power generation is significantly affected by wind patterns, and it is important to understand this seasonal and decadal variability for long-term power generation from wind turbines. This study focused on the trends of changes in wind pattern and its strength at two hub-heights (80 m and 110 m) over 30-years (1986 to 2015). We only analyzed summer data(June to September) because of concentrated electricity usage in Texas. We extracted hub-height wind data (U and V components) from the three-hourly National Centers for Environmental Prediction-North American Regional Reanalysis (NCEP-NARR) and classified wind patterns properly by using nonhierarchical K-means method. Hub-height wind patterns in summer seasons of 1986 to 2015 were classified in six classes at day and seven classes at night. Mean wind speed was 4.6 ms-1 at day and 5.4 ms-1 at night, but showed large variability in time and space. We combined each cluster's frequencies and wind speed tendencies with large scale atmospheric circulation features and quantified the amount of wind power generation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP11C1047T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP11C1047T"><span>Recent Increase in North Atlantic Jet Variability Emerges from Three-Century Long Context</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Trouet, V.; Babst, F.; Meko, M. D.</p> <p>2017-12-01</p> <p>The position and strength of the Northern Hemisphere polar jet stream are important modulators of mid-latitude weather extremes and their societal, ecosystem, and economic impacts. A recent increase in mid-latitude extreme events highlights the need for long-term records of jet stream variability to put recent trends in a historical perspective and to investigate non-linear relationships between jet stream variability, mid-latitude extreme weather events, and anthropogenic climate change. In Europe, anomalies of the North Atlantic Jet (NAJ) create a summer temperature seesaw between the British Isles (BRIT) and the northeastern Mediterranean (NEMED). We combined summer temperature-sensitive tree-ring records from BRIT and NEMED to reconstruct inter-annual variability in the latitudinal position of the August NAJ back to 1725 CE. The two temperature proxies BRIT and NEMED counter-correlate significantly over their period of overlap, thus illustrate the temperature dipole generated by anomalous NAJ positions, and combined explain close to 40% of the variance in the August NAJ target (Fig. 1). The NAJ reconstruction is dominated by sub-decadal variability and no significant long-term poleward or equatorward trends were detected. However, the NAJ time series shows a steep and unprecedented increase in variance starting in the late 1960s. Enhanced late 20th century variance has also been detected in climate and ecosystem dynamics in the Central and Northeast Pacific, which are associated with the latitudinal position of the North Pacific Jet. Our combined results suggest a late 20th century increase in jet stream latitudinal variance in the North Atlantic and the North Pacific Basin that can be indicative of enhanced jet stream waviness and that coincides with a recent increase in quasi-resonant amplification (QRA). Our results show a late 20th century amplification of meridional flow in both the North Pacific and the North Atlantic Basin and support more sinuous jet stream patterns and QRA as potential dynamic pathways for Arctic warming to influence midlatitude weather. Moreover, the synchronization of variance increases between the North Atlantic and North Pacific basins in the late 20th century is unprecedented over the last 290 years and strongly suggests an impact of anthropogenic warming.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H42G..02D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H42G..02D"><span>Trends and variability of water quality in Lake Tana, Ethiopia using MODIS-Aqua</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>DeLuca, N. M.; Zaitchik, B. F.; Monger, B. C.</p> <p>2017-12-01</p> <p>Determining long-term water quality trends and variability in remote inland lakes has been challenging due to a lack of continuous in situ measurements. Utilizing ocean color remote sensing techniques for these lakes is difficult due to their sizes, shapes, and optically complex waters. Lake Tana is the largest body of water in Ethiopia, and is located in the country's northwestern highlands. The lake is quite shallow, averaging at about 8 meters depth, and is characteristically turbid due to nearby land degradation and high soil erosion rates. Lake Tana is an important source of accessible water for the rapidly growing population of Ethiopia and serves as the headwaters for the Blue Nile. Therefore, understanding water quality trends and seasonal variation over the past decade is essential to better preparing for future water needs. Here we use MODIS-Aqua data spanning years 2002-2016 to investigate these trends and variability in Lake Tana, where in situ measurements are limited. Daily water quality products were first processed using SeaDAS and then aggregated by month and year for analyses. Frequent cloud cover in the June, July, and August (JJA) rainy season due to monsoon and zonal dynamics presents an obstacle for obtaining mean lake values during these months. We also performed analyses on targeted regions of Lake Tana to determine whether some of the major tributaries and their corresponding watersheds have more influence on observed trends than others.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1918609P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1918609P"><span>Long-term observations of cloud condensation nuclei in the Amazon rain forest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pöhlker, Mira L.; Pöhlker, Christopher; Ditas, Florian; Klimach, Thomas; Hrabe de Angelis, Isabella; Brito, Joel; Carbone, Samara; Cheng, Yafang; Martin, Scot T.; Moran-Zuloaga, Daniel; Rose, Diana; Saturno, Jorge; Su, Hang; Thalman, Ryan; Walter, David; Wang, Jian; Barbosa, Henrique; Artaxo, Paulo; Andreae, Meinrat O.; Pöschl, Ulrich</p> <p>2017-04-01</p> <p>Size-resolved long-term measurements of atmospheric aerosol and cloud condensation nuclei (CCN) concentrations and hygroscopicity were conducted at the remote Amazon Tall Tower Observatory (ATTO) in the central Amazon Basin over a full seasonal cycle (Mar 2014 - Feb 2015). The measurements provide a climatology of CCN properties characteristic of a remote central Amazonian rain forest site [1,2]. The CCN measurements were continuously cycled through 10 levels of supersaturation (S = 0.11 to 1.10 %) and span the aerosol particle size range from 20 to 245 nm. The particle hygroscopicity exhibits a pronounced size dependence with lower values for the Aitken mode (κAit = 0.14 ± 0.03), higher values for the accumulation mode (κAcc = 0.22 ± 0.05), and an overall mean value of κmean = 0.17 ± 0.06, consistent with high fractions of organic aerosol. The hygroscopicity parameter, κ, exhibits remarkably little temporal variability: no pronounced diurnal cycles, only weak seasonal trends, and few short-term variations during long-range transport events. In contrast, the CCN number concentrations exhibit a pronounced seasonal cycle, tracking the pollution-related seasonality in total aerosol concentration. We find that the variability in the CCN concentrations in the central Amazon is mostly driven by aerosol particle number concentration and size distribution, while variations in aerosol hygroscopicity and chemical composition matter only during a few episodes. For modelling purposes, we compare different approaches of predicting CCN number concentration and present a novel parameterization, which allows accurate CCN predictions based on a small set of input data. In addition, we analyzed the CCN short-term variability in relation to air mass changes as well as aerosol emission and transformation processes. The CCN short term variability is presented for selected case studies, which analyze particularly interesting and characteristic events/conditions in the Amazon region. References: [1] Andreae, M. O., et al. (2015), Atmos. Chem. Phys., 15, 10723-10776. [2] Pöhlker, M. L.., et al. (2016), Atmos. Chem. Phys., 16, 15709-15740.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMOS13A1793K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMOS13A1793K"><span>Uncovering the Anthropogenic Sea Level Change using an Improved Sea Level Reconstruction for the Indian Ocean</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kumar, P.; Hamlington, B.; Thompson, P. R.; Han, W.</p> <p>2016-12-01</p> <p>Despite having some of the world's most densely populated and vulnerable coastal regions, sea level (SL) variability in the Indian Ocean (IO) has received considerably less attention than the Pacific Ocean. Differentiating the internal variability from the long-term trend in global mean sea level (GMSL) at decadal time-scales is vital for planning and mitigation efforts in the IO region. Understanding the dynamics of internal and anthropogenic SL change is essential for understanding the dynamic pathways that link the IO basin to terrestrial climates world-wide. With a sparse pre-satellite observational record of the IO, the Indo-Pacific internal climate variability is difficult to represent accurately. However, an improved representation of pre-satellite SL variability can be achieved by using a multivariate reconstruction technique. By using cyclostationary empirical orthogonal functions (CSEOFs) that can capture time-varying spatial patterns, gaps in the historical record when observations are sparse are filled using spatial relationships from time periods when the observational network is dense. This reconstruction method combines SL data and sea surface temperature (SST) to create a SL reconstruction that spans a period from 1900 to present, long enough to study climate signals over interannual to decadal time scales. This study aims at estimating the component of SL rise that relates to anthropogenic forcing by identifying and removing the fraction related to internal variability. An improved understanding of how the internal climate variability can affect the IO SL trend and variability, will provide an insight into the future SL changes. It is also important to study links between SL and climate variability in the past to understand how SL will respond to similar climatic events in the future and if this response will be influenced by the changing climate.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/13119','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/13119"><span>Long-term trends from ecosystem research at the Hubbard Brook Experimental Forest</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>John L. Campbell; Charles T. Driscoll; Christopher Eagar; Gene E. Likens; Thomas G. Siccama; Chris E. Johnson; Timothy J. Fahey; Steven P. Hamburg; Richard T. Holmes; Amey S. Bailey; Donald C. Buso</p> <p>2007-01-01</p> <p>Summarizes 52 years of collaborative, long-term research conducted at the Hubbard Brook (NH) Experimental Forest on ecosystem response to disturbances such as air pollution, climate change, forest disturbance, and forest management practices. Also provides explanations of some of the trends and lists references from scientific literature for further reading.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26093368','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26093368"><span>Sleep variability in adolescence is associated with altered brain development.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Telzer, Eva H; Goldenberg, Diane; Fuligni, Andrew J; Lieberman, Matthew D; Gálvan, Adriana</p> <p>2015-08-01</p> <p>Despite the known importance of sleep for brain development, and the sharp increase in poor sleep during adolescence, we know relatively little about how sleep impacts the developing brain. We present the first longitudinal study to examine how sleep during adolescence is associated with white matter integrity. We find that greater variability in sleep duration one year prior to a DTI scan is associated with lower white matter integrity above and beyond the effects of sleep duration, and variability in bedtime, whereas sleep variability a few months prior to the scan is not associated with white matter integrity. Thus, variability in sleep duration during adolescence may have long-term impairments on the developing brain. White matter integrity should be increasing during adolescence, and so sleep variability is directly at odds with normative developmental trends. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140011867','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140011867"><span>A Global Assessment of Long-Term Greening and Browning Trends in Pasture Lands Using the GIMMS LAI3g Dataset</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cook, Benjamin I.; Pau, Stephanie</p> <p>2013-01-01</p> <p>Pasture ecosystems may be particularly vulnerable to land degradation due to the high risk of human disturbance (e.g., overgrazing, burning, etc.), especially when compared with natural ecosystems (non-pasture, non-cultivated) where direct human impacts are minimal. Using maximum annual leaf area index (LAImax) as a proxy for standing biomass and peak annual aboveground productivity, we analyze greening and browning trends in pasture areas from 1982-2008. Inter-annual variability in pasture productivity is strongly controlled by precipitation (positive correlation) and, to a lesser extent, temperature (negative correlation). Linear temporal trends are significant in 23% of pasture cells, with the vast majority of these areas showing positive LAImax trends. Spatially extensive productivity declines are only found in a few regions, most notably central Asia, southwest North America, and southeast Australia. Statistically removing the influence of precipitation reduces LAImax trends by only 13%, suggesting that precipitation trends are only a minor contributor to long-term greening and browning of pasture lands. No significant global relationship was found between LAImax and pasture intensity, although the magnitude of trends did vary between cells classified as natural versus pasture. In the tropics and Southern Hemisphere, the median rate of greening in pasture cells is significantly higher than for cells dominated by natural vegetation. In the Northern Hemisphere extra-tropics, conversely, greening of natural areas is 2-4 times the magnitude of greening in pasture areas. This analysis presents one of the first global assessments of greening and browning trends in global pasture lands, including a comparison with vegetation trends in regions dominated by natural ecosystems. Our results suggest that degradation of pasture lands is not a globally widespread phenomenon and, consistent with much of the terrestrial biosphere, there have been widespread increases in pasture productivity over the last 30 years.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2011/5123/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2011/5123/"><span>Trends in lake chemistry in response to atmospheric deposition and climate in selected Class I wilderness areas in Colorado, Idaho, Utah, and Wyoming, 1993-2009</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Mast, M. Alisa; Ingersoll, George P.</p> <p>2011-01-01</p> <p>In 2010, the U.S. Geological Survey, in cooperation with the U.S. Department of Agriculture Forest Service, Air Resource Management, began a study to evaluate long-term trends in lake-water chemistry for 64 high-elevation lakes in selected Class I wilderness areas in Colorado, Idaho, Utah, and Wyoming during 1993 to 2009. The purpose of this report is to describe trends in the chemical composition of these high-elevation lakes. Trends in emissions, atmospheric deposition, and climate variables (air temperature and precipitation amount) are evaluated over a similar period of record to determine likely drivers of changing lake chemistry. Sulfate concentrations in precipitation decreased over the past two decades at high-elevation monitoring stations in the Rocky Mountain region. The trend in deposition chemistry is consistent with regional declines in sulfur dioxide emissions resulting from installation of emission controls at large stationary sources. Trends in nitrogen deposition were not as widespread as those for sulfate. About one-half of monitoring stations showed increases in ammonium concentrations, but few showed significant changes in nitrate concentrations. Trends in nitrogen deposition appear to be inconsistent with available emission inventories, which indicate modest declines in nitrogen emissions in the Rocky Mountain region since the mid-1990s. This discrepancy may reflect uncertainties in emission inventories or changes in atmospheric transformations of nitrogen species that may be affecting deposition processes. Analysis of long-term climate records indicates that average annual mean air temperature minimums have increased from 0.57 to 0.75 °C per decade in mountain areas of the region with warming trends being more pronounced in Colorado. Trends in annual precipitation were not evident over the period 1990 to 2006, although wetter than average years during 1995 to 1997 and drier years during 2001 to 2004 caused a notable decline in precipitation in the middle part of the record.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080047282','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080047282"><span>The Spatiotemporal Structure of 20th Century Climate Variations in Observations and Reanalyses. Part 1; Long-term Trend</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chen, Junye; DelGenio, Anthony D.; Carlson, Barbara e.; Bosilovich, Michael G.</p> <p>2007-01-01</p> <p>The dominant interannual El Nino-Southern Oscillation phenomenon (ENSO) and the short length of climate observation records make it difficult to study long-term climate variations in the spatiotemporal domain. Based on the fact that the ENS0 signal spreads to remote regions and induces delayed climate variation through atmospheric teleconnections, we develop an ENSO-removal method through which the ENS0 signal can be approximately removed at the grid box level from the spatiotemporal field of a climate parameter. After this signal is removed, long-term climate variations, namely, the global warming trend (GW) and the Pacific pan-decadal variability (PDV), are isolated at middle and low latitudes in the climate parameter fields from observed and reanalyses datasets. Except for known GW characteristics, the warming that occurs in the Pacific basin (approximately 0.4K in the 2oth century) is much weaker than in surrounding regions and the other two ocean basins (approximately 0.8K). The modest warming in the Pacific basin is likely due to its dynamic nature on the interannual and decadal time scales and/or the leakage of upper ocean water through the Indonesian Throughflow. Based on NCEP/NCAR and ERA-40 reanalyses, a comprehensive atmospheric structure associated with GW is given. Significant discrepancies exist between the two datasets, especially in the tightly coupled dynamic and water vapor fields. The dynamic field based on NCEP/NCAR reanalysis, which shows a change in the Walker Circulation, is consistent with the GW change in the surface temperature field. However, intensification in the Hadley Circulation is associated with GW trend in the ERA-40 reanalysis.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.H53K1555E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.H53K1555E"><span>Trends in Surface-Water Nitrate-N Concentrations and Loads from Predominantly-Forested Watersheds of the Chesapeake Bay Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eshleman, K. N.</p> <p>2011-12-01</p> <p>Water quality monitoring data from streams and rivers provide the "gold standard" by which progress toward achieving real reductions in nutrient loadings to Chesapeake Bay must ultimately be assessed. The most recent trend results posted at the Chesapeake Bay Program (CBP) website reveal that a substantial percentage of tributaries are now showing long-term declines in flow-adjusted concentrations of nutrients and sediments: 22 sites showed statistically significant (p < 0.05) downward trends (1985-2010) in flow-adjusted concentrations, two sites showed upward trends, and eight sites showed no trend. Based on the data, the CBP has drawn the following conclusion: "At many monitored locations, long-term trends indicate that management actions, such as pollution controls for improved wastewater treatment plants and practices to reduce nutrients on farms and suburban lands, have reduced concentrations of nitrogen." But could this conclusion be pre-mature? I recently undertook a comparable analysis of long-term nitrate-N trends for a different group of watersheds (all located in the Chesapeake Bay watershed with long data records); this group includes nine watersheds that are predominantly (i.e., >75%) forested, plus five other Potomac River subwatersheds added for comparison. Based on comparable data and analytical methods to those used by CBP partners and USGS, 13 of the 14 sites-including both Potomac River stations (Chain Bridge at Washington DC and Hancock, Maryland)-showed statistically significant decreasing linear trends in annual flow-weighted nitrate-N concentration. Only one station-the heavily agricultural Upper Monocacy River-did not show a statistically significant (p < 0.05) trend. Five of the predominantly-forested watersheds also showed statistically significant decreasing trends in annual nitrate-N loads, and none of the stations showed a trend in annual runoff presumably due to high inter-annual hydroclimatological variability. While the largest absolute changes in nitrate-N concentration corresponded to the least forested watersheds, the largest percentage changes in nitrate-N concentration were actually observed for those watersheds with the greatest percentages of forestland. This result suggests that the natural dynamics of forests may be playing a very important (and under-appreciated) role in improving water quality throughout the Bay watershed. A second interesting finding was that the statistically significant reductions in annual nitrate-N concentration at the Potomac River RIM station could be entirely explained by commensurate improvements at the upstream (Hancock) station; in fact, no trend in nitrate-N concentration associated with the eastern portion of the basin was found (after subtracting out the influence of the upstream portion). Additional research is needed to understand why nitrogen retention by forested lands may be increasing and thus helping restore water quality throughout the Chesapeake Bay watershed. The results also have obvious implications for meeting local water quality goals as well as the basin-wide goal of the Chesapeake Bay TMDL for nitrogen.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29089011','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29089011"><span>Long-Term Use of Benzodiazepines and Nonbenzodiazepine Hypnotics, 1999-2014.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kaufmann, Christopher N; Spira, Adam P; Depp, Colin A; Mojtabai, Ramin</p> <p>2018-02-01</p> <p>Clinical guidelines suggest that benzodiazepines (BZDs) and non-BZD hypnotics (NBHs) be used on a short-term basis. The authors examined trends in long-term BZD and NBH use from 1999 to 2014. Data included 82,091 respondents in the 1999-2014 waves of the National Health and Nutrition Examination Survey (NHANES). NHANES recorded medications used in the past 30 days on the basis of prescription bottles, and participants reported use duration. BZD and NBH use were categorized as short, medium, and long term, and time trends in use were assessed. BZD and NBH use increased from 1999 to 2014, driven by increases in medium- and long-term use, even after adjustment for age and race-ethnicity. In most years, only a fifth of current BZD or NBH users reported short-term use. Long-term BZD and NBH use has grown independent of U.S. demographic shifts. Monitoring of use is needed to prevent adverse outcomes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMNH43A0195S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMNH43A0195S"><span>Assessment of rainfall thresholds for landslide triggering in the Pacific Northwest: extreme short-term rainfall and long-term trends</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stanley, T.; Kirschbaum, D.; Sobieszczyk, S.; Jasinski, M. F.; Borak, J.; Yatheendradas, S.</p> <p>2017-12-01</p> <p>Landslides occur every year in the U.S. Pacific Northwest due to extreme rainfall, snow cover, and rugged topography. Data for 15,000 landslide events in Washington and Oregon were assembled from State Surveys, Departments of Transportation, a Global Landslide Catalog compiled by NASA, and other sources. This new inventory was evaluated against rainfall data from the National Climate Assessment (NCA) Land Data Assimilation System to characterize the regional rainfall conditions that trigger landslides. Analysis of these data sets indicates clear differences in triggering thresholds between extreme weather systems such as a Pineapple Express and the more typical peak seasonal rainfall between November and February. The study also leverages over 30 years of precipitation and land surface information to inform variability of landslide triggering over multiple decades and landslide trends within the region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED398845.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED398845.pdf"><span>Long-Term Economic and Labor Forecast Trends for Washington. 1996.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Lefberg, Irv; And Others</p> <p></p> <p>This publication provides actual historical and long-term forecast data on labor force, total wage and salary employment, industry employment, and personal income for the state of Washington. The data are based upon the Washington Office of Financial Management long-term population forecast. Chapter 1 presents long-term forecasts of Washington…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23186616','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23186616"><span>Temporal trend of green space coverage in China and its relationship with urbanization over the last two decades.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhao, Juanjuan; Chen, Shengbin; Jiang, Bo; Ren, Yin; Wang, Hua; Vause, Jonathan; Yu, Haidong</p> <p>2013-01-01</p> <p>Irrespective of which side is taken in the densification-sprawl debate, insights into the relationship between urban green space coverage and urbanization have been recognized as essential for guiding sustainable urban development. However, knowledge of the relationships between socio-economic variables of urbanization and long-term green space change is still limited. In this paper, using simple regression, hierarchical partitioning and multi-regression, the temporal trend in green space coverage and its relationship with urbanization were investigated using data from 286 cities between 1989 and 2009, covering all provinces in mainland China with the exception of Tibet. We found that: [1] average green space coverage of cities investigated increased steadily from 17.0% in 1989 to 37.3% in 2009; [2] cities with higher recent green space coverage also had relatively higher green space coverage historically; [3] cities in the same region exhibited similar long-term trends in green space coverage; [4] eight of the nine variables characterizing urbanization showed a significant positive linear relationship with green space coverage, with 'per capita GDP' having the highest independent contribution (24.2%); [5] among the climatic and geographic factors investigated, only mean elevation showed a significant effect; and [6] using the seven largest contributing individual factors, a linear model to predict variance in green space coverage was constructed. Here, we demonstrated that green space coverage in built-up areas tended to reflect the effects of urbanization rather than those of climatic or geographic factors. Quantification of the urbanization effects and the characteristics of green space development in China may provide a valuable reference for research into the processes of urban sprawl and its relationship with green space change. Copyright © 2012 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JESS..124....1J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JESS..124....1J"><span>Climatology and trends of summer high temperature days in India during 1969-2013</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jaswal, A. K.; Rao, P. C. S.; Singh, Virendra</p> <p>2015-02-01</p> <p>Based on the daily maximum air temperature data from 176 stations in India from 1969 to 2013, the climatological distribution of the number of days with high temperature (HT) defined as days with maximum temperature higher than 37°C during summer season (March-June) are studied. With a focus on the regional variability and long-term trends, the impacts of HT days are examined by dividing the country into six geographical regions (North, West, North-central, East, South-central and South). Although the long-term (1969-2013) climatological numbers of HT days display well-defined spatial patterns, there is clear change in climatological mean and coefficient of variation of HT days in a recent period (1991-2013). The long period trends indicate increase in summer HT days by 3%, 5%, and 18% in north, west, and south regions, respectively and decrease by 4% and 9% in north-central and east regions respectively. However, spatial variations in HT days exist across different regions in the country. The data analysis shows that 2010 was the warmest summer year and 2013 was the coolest summer year in India. Comparison of spatial distributions of trends in HT days for 1969-1990 and 1991-2013 periods reveal that there is an abrupt increase in the number of HT days over north, west and north-central regions of India probably from mid 1990s. A steep increase in summer HT days in highly populated cities of Mumbai, New Delhi, Chennai, Jaipur, and Visakhapatnam is noticed during the recent period of 1991-2013. The summer HT days over southern India indicate significant positive correlation with Nino 3.4 index for three months' running mean (December-January-February, January-March, February-April, March-May and April-June).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70024935','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70024935"><span>Historical trend in river ice thickness and coherence in hydroclimatological trends in Maine</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Huntington, T.G.; Hodgkins, G.A.; Dudley, R.W.</p> <p>2003-01-01</p> <p>We analyzed long-term records of ice thickness on the Piscataquis River in central Maine and air temperature in Maine to determine whether there were temporal trends that were associated with climate warming. The trend in ice thickness was compared and correlated with regional time series of winter air temperature, heating degree days (HDD), date of river ice-out, seasonal center-of-volume date (SCVD) (date on which half of the stream runoff volume during the period 1 Jan. to 31 May has occurred), water temperature, and lake ice-out date. All of these variables except lake ice-out date showed significant temporal trends during the 20th century. Average ice thickness around 28 February decreased by about 23 cm from 1912 to 2001. Over the period 1900 to 1999, winter air temperature increased by 1.7??C and HDD decreased by about 7.5%. Final ice-out date on the Piscataquis River occurred earlier (advanced), by 0.21 days yr-1 over the period 1931 to 2002, and the SCVD advanced by 0.11 days yr-1 over the period 1903 to 2001. Ice thickness was significantly correlated (P-value < 0.01) with winter air temperature, HDD, river ice-out, and SCVD. These systematic temporal trends in multiple hydrologic indicator variables indicate a coherent response to climate forcing.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23681324','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23681324"><span>[Falls and fractures among older adults living in long-term care].</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Del Duca, Giovâni Firpo; Antes, Danielle Ledur; Hallal, Pedro Curi</p> <p>2013-03-01</p> <p>To investigate the prevalence of falls and fractures over the past 12 months and associated factors among older adults living in long-term care. Census of all long-term care located in the city of Pelotas, Brazil, in 2008. Falls over the past 12 months were assessed using the following question: "Over the last 12 months, have you fallen?" For those who replied positively, another question was asked: "In any of these falls, have you fractured a bone?" Sex, age, schooling, disability relating to basic activities of daily living, type of financing of the long-term care and hospital admissions were the independent variables. We used chi-square tests for heterogeneity and linear trend in the unadjusted analysis, and Poisson regression with robust variance in the adjusted one. Within the 24 long-term care studied, we collected data for 466 individuals. The prevalence of falls in the past year was 38.9% (95%CI 34.5; 43.4). Among those who have fallen, 19.2% had fractures. Femur (hip) was the most frequent site fractured (43.4%), followed by wrist (10%). In the adjusted analysis, older age, disability for 1-5 basic activities of daily living, living in public institutions and hospital admissions in the last year were associated with higher risk of falls. The high prevalence of falls and fractures highlights the fragility of the individuals living in long-term care. Special attention should be paid to older adults and those with hospital admissions in the last year.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22173700','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22173700"><span>Temporal trends in long-term survival and cure rates in esophageal cancer: a SEER database analysis.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dubecz, Attila; Gall, Isabell; Solymosi, Norbert; Schweigert, Michael; Peters, Jeffrey H; Feith, Marcus; Stein, Hubert J</p> <p>2012-02-01</p> <p>To assess long-term temporal trends in population-based survival and cure rates in patients with esophageal cancer and compare them over the last 3 decades in the United States. We identified 62,523 patients with cancer of the esophagus and the gastric cardia diagnosed between 1973 and 2007 from the Surveillance, Epidemiology, and End Results database. Long-term cancer-related survival and cure rates were calculated. Stage-by-stage disease-related survival curves of patients diagnosed in different decades were compared. Influence of available variables on survival and cure was analyzed with logistic regression. Ten-year survival was 14% in all patients. Disease-related survival of esophageal cancer improved significantly since 1973. Median survival in Surveillance, Epidemiology, and End Results stages in local, regional, and metastatic cancers improved from 11, 10, and 4 months in the 1970s to 35, 15, and 6 months after 2000. Early stage, age 45 to 65 years at diagnosis and undergoing surgical therapy were independent predictors of 10-year survival. Cure rate improved in all stages during the study period and were 73%, 37%, 12%, and 2% in stages 0, 1, 2, and 4, respectively, after the year 2000. Percentage of patients undergoing surgery improved from 55% in the 1970s to 64% between 2000 and 2007. Proportion of patients diagnosed with in situ and local cancer remains below 30%. Long-term survival with esophageal cancer is poor but survival of local esophageal cancer improved dramatically over the decades. Complete cure of nonmetastatic esophageal cancer seems possible in a growing number of patients. Early diagnosis and treatment are crucial.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013IJBm...57..317L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013IJBm...57..317L"><span>A comprehensive overview of the spatial and temporal variability of apple bud dormancy release and blooming phenology in Western Europe</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Legave, Jean Michel; Blanke, Michael; Christen, Danilo; Giovannini, Daniela; Mathieu, Vincent; Oger, Robert</p> <p>2013-03-01</p> <p>In the current context of global warming, an analysis is required of spatially-extensive and long-term blooming data in fruit trees to make up for insufficient information on regional-scale blooming changes and determinisms that are key to the phenological adaptation of these species. We therefore analysed blooming dates over long periods at climate-contrasted sites in Western Europe, focusing mainly on the Golden Delicious apple that is grown worldwide. On average, blooming advances were more pronounced in northern continental (10 days) than in western oceanic (6-7 days) regions, while the shortest advance was found on the Mediterranean coastline. Temporal trends toward blooming phase shortenings were also observed in continental regions. These regional differences in temporal variability across Western Europe resulted in a decrease in spatial variability, i.e. shorter time intervals between blooming dates in contrasted regions (8-10-day decrease for full bloom between Mediterranean and continental regions). Fitted sequential models were used to reproduce phenological changes. Marked trends toward shorter simulated durations of forcing period (bud growth from dormancy release to blooming) and high positive correlations between these durations and observed blooming dates support the notion that blooming advances and shortenings are mainly due to faster satisfaction of the heating requirement. However, trends toward later dormancy releases were also noted in oceanic and Mediterranean regions. This could tend toward blooming delays and explain the shorter advances in these regions despite similar or greater warming. The regional differences in simulated chilling and forcing periods were consistent with the regional differences in temperature increases.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ECSS...94..263S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ECSS...94..263S"><span>Long-term trends in the structure of eastern Adriatic littoral fish assemblages: Consequences for fisheries management</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stagličić, N.; Matić-Skoko, S.; Pallaoro, A.; Grgičević, R.; Kraljević, M.; Tutman, P.; Dragičević, B.; Dulčić, J.</p> <p>2011-09-01</p> <p>Long-term interannual changes in abundance, biomass, diversity and structure of littoral fish assemblages were examined between 1993 and 2009 by experimental trammel net fishing up to six times per year, within the warm period - May to September, at multiple areas along the eastern Adriatic coast with the aim of testing for the consistency of patterns of change across a large spatial scale (˜600 km). The results revealed spatially consistent increasing trends of total fish abundance and biomass growing at an average rate of 15 and 14% per year, respectively. Of the diversity indices analysed, the same pattern of variability was observed for Shannon diversity, while Pielou evenness and average taxonomic distinctness measures Δ ∗ and Δ + showed spatial variability with no obvious temporal trends. Multivariate fish assemblage structure underwent a directional change displaying a similar pattern through time for all the areas. The structural change in fish assemblages generally involved most of the species present in trammel net catches. A large pool of fish species responsible for producing the temporal pattern of assemblage change was relatively different in each of the areas reflecting a large geographic range covered by the study. An analysis of 4 fish species ( Symphodus tinca, Pagellus erythrinus, Mullus surmuletus, Scorpaena porcus) common to each of the study areas as the ones driving the temporal change indicated that there were clear increasing trends of their mean catches across the years at all the study areas. A common pattern among time trajectories across the spatial scale studied implies that the factor affecting the littoral fish assemblages is not localised but regional in nature. As an underlying factor having the potential to induce such widespread and consistent improvements in littoral fish assemblages, a more restrictive artisanal fishery management that has progressively been put in place during the study period, is suggested and discussed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27907262','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27907262"><span>Potential breeding distributions of U.S. birds predicted with both short-term variability and long-term average climate data.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bateman, Brooke L; Pidgeon, Anna M; Radeloff, Volker C; Flather, Curtis H; VanDerWal, Jeremy; Akçakaya, H Resit; Thogmartin, Wayne E; Albright, Thomas P; Vavrus, Stephen J; Heglund, Patricia J</p> <p>2016-12-01</p> <p>Climate conditions, such as temperature or precipitation, averaged over several decades strongly affect species distributions, as evidenced by experimental results and a plethora of models demonstrating statistical relations between species occurrences and long-term climate averages. However, long-term averages can conceal climate changes that have occurred in recent decades and may not capture actual species occurrence well because the distributions of species, especially at the edges of their range, are typically dynamic and may respond strongly to short-term climate variability. Our goal here was to test whether bird occurrence models can be predicted by either covariates based on short-term climate variability or on long-term climate averages. We parameterized species distribution models (SDMs) based on either short-term variability or long-term average climate covariates for 320 bird species in the conterminous USA and tested whether any life-history trait-based guilds were particularly sensitive to short-term conditions. Models including short-term climate variability performed well based on their cross-validated area-under-the-curve AUC score (0.85), as did models based on long-term climate averages (0.84). Similarly, both models performed well compared to independent presence/absence data from the North American Breeding Bird Survey (independent AUC of 0.89 and 0.90, respectively). However, models based on short-term variability covariates more accurately classified true absences for most species (73% of true absences classified within the lowest quarter of environmental suitability vs. 68%). In addition, they have the advantage that they can reveal the dynamic relationship between species and their environment because they capture the spatial fluctuations of species potential breeding distributions. With this information, we can identify which species and guilds are sensitive to climate variability, identify sites of high conservation value where climate variability is low, and assess how species' potential distributions may have already shifted due recent climate change. However, long-term climate averages require less data and processing time and may be more readily available for some areas of interest. Where data on short-term climate variability are not available, long-term climate information is a sufficient predictor of species distributions in many cases. However, short-term climate variability data may provide information not captured with long-term climate data for use in SDMs. © 2016 by the Ecological Society of America.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21564524','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21564524"><span>Solid organ allograft survival improvement in the United States: the long-term does not mirror the dramatic short-term success.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lodhi, S A; Lamb, K E; Meier-Kriesche, H U</p> <p>2011-06-01</p> <p>Organ survival in the short-term period post-transplant has improved dramatically over the past few decades. Whether this has translated to a long-term survival benefit remains unclear. This study quantifies the progression of nonrenal solid organ transplant outcomes from 1989 to 2009 in liver, lung, heart, intestine and pancreas transplants. Long-term graft survival was analyzed using data on adult solid organ transplant recipients from the UNOS/SRTR database and is reported as organ half-life and yearly attrition rates. Liver, lung, heart, intestine and pancreas half-lives have improved from 5.8 to 8.5, 1.7 to 5.2, 8.8 to 11, 2.1 to 3.6 and 10.5 to 16.7 years, respectively. Long-term attrition rates have not shown the same consistent improvement, with the yearly attrition rate 5-10 years post-transplant for liver, lung, heart and pancreas changing from 4.7 to 4.3, 10.9 to 10.1, 6.4 to 5.1 and 3.3 to 4.2, respectively. Attrition rates for intestine and pancreas transplantation alone display more variability due to smaller sample size but exhibit similar trends of improved first-year attrition and relatively stagnant long-term attrition rates. With first-year survival and attrition rates almost at a pinnacle, further progress in long-term survival will come from targeting endpoints beyond first-year rejection and survival rates. ©2011 The Authors Journal compilation©2011 The American Society of Transplantation and the American Society of Transplant Surgeons.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ECSS..162...53H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ECSS..162...53H"><span>Climate effects on phytoplankton floral composition in Chesapeake Bay</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harding, L. W.; Adolf, J. E.; Mallonee, M. E.; Miller, W. D.; Gallegos, C. L.; Perry, E. S.; Johnson, J. M.; Sellner, K. G.; Paerl, H. W.</p> <p>2015-09-01</p> <p>Long-term data on floral composition of phytoplankton are presented to document seasonal and inter-annual variability in Chesapeake Bay related to climate effects on hydrology. Source data consist of the abundances of major taxonomic groups of phytoplankton derived from algal photopigments (1995-2004) and cell counts (1985-2007). Algal photopigments were measured by high-performance liquid chromatography (HPLC) and analyzed using the software CHEMTAX to determine the proportions of chlorophyll-a (chl-a) in major taxonomic groups. Cell counts determined microscopically provided species identifications, enumeration, and dimensions used to obtain proportions of cell volume (CV), plasma volume (PV), and carbon (C) in the same taxonomic groups. We drew upon these two independent data sets to take advantage of the unique strengths of each method, using comparable quantitative measures to express floral composition for the main stem bay. Spatial and temporal variability of floral composition was quantified using data aggregated by season, year, and salinity zone. Both time-series were sufficiently long to encompass the drought-flood cycle with commensurate effects on inputs of freshwater and solutes. Diatoms emerged as the predominant taxonomic group, with significant contributions by dinoflagellates, cryptophytes, and cyanobacteria, depending on salinity zone and season. Our analyses revealed increased abundance of diatoms in wet years compared to long-term average (LTA) or dry years. Results are presented in the context of long-term nutrient over-enrichment of the bay, punctuated by inter-annual variability of freshwater flow that strongly affects nutrient loading, chl-a, and floral composition. Statistical analyses generated flow-adjusted diatom abundance and showed significant trends late in the time series, suggesting current and future decreases of nutrient inputs may lead to a reduction of the proportion of biomass comprised by diatoms in an increasingly diverse flora.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H13J1534E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H13J1534E"><span>Do climate model predictions agree with long-term precipitation trends in the arid southwestern United States?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Elias, E.; Rango, A.; James, D.; Maxwell, C.; Anderson, J.; Abatzoglou, J. T.</p> <p>2016-12-01</p> <p>Researchers evaluating climate projections across southwestern North America observed a decreasing precipitation trend. Aridification was most pronounced in the cold (non-monsoonal) season, whereas downward trends in precipitation were smaller in the warm (monsoonal) season. In this region, based upon a multimodel mean of 20 Coupled Model Intercomparison Project 5 models using a business-as-usual (Representative Concentration Pathway 8.5) trajectory, midcentury precipitation is projected to increase slightly during the monsoonal time period (July-September; 6%) and decrease slightly during the remainder of the year (October-June; -4%). We use observed long-term (1915-2015) monthly precipitation records from 16 weather stations to investigate how well measured trends corroborate climate model predictions during the monsoonal and non-monsoonal timeframe. Running trend analysis using the Mann-Kendall test for 15 to 101 year moving windows reveals that half the stations showed significant (p≤0.1), albeit small, increasing trends based on the longest term record. Trends based on shorter-term records reveal a period of significant precipitation decline at all stations representing the 1950s drought. Trends from 1930 to 2015 reveal significant annual, monsoonal and non-monsoonal increases in precipitation (Fig 1). The 1960 to 2015 time window shows no significant precipitation trends. The more recent time window (1980 to 2015) shows a slight, but not significant, increase in monsoonal precipitation and a larger, significant decline in non-monsoonal precipitation. GCM precipitation projections are consistent with more recent trends for the region. Running trends from the most recent time window (mid-1990s to 2015) at all stations show increasing monsoonal precipitation and decreasing Oct-Jun precipitation, with significant trends at 6 of 16 stations. Running trend analysis revealed that the long-term trends were not persistent throughout the series length, but depended on the period examined. Recent trends in Southwest precipitation are directionally consistent with anthropogenic climate change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29110145','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29110145"><span>Cohort Measures of Internal Migration: Understanding Long-Term Trends.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bernard, Aude</p> <p>2017-12-01</p> <p>Internal migration intensities fluctuate over time, but both migration levels and trends show great diversity. The dynamics underpinning these trends remain poorly understood because they are analyzed almost exclusively by applying period measures to cross-sectional data. This article proposes 10 cohort measures that can be applied to both prospective and retrospective data to systematically examine long-term trends. To demonstrate their benefits, the proposed measures are applied to retrospective survey data for England that provide residential histories from birth to age 50 for cohorts born between 1918 and 1957. The analysis reveals stable lifetime migration for men but increased lifetime migration for women associated with earlier ages at moving in adulthood and a compression of intervals between consecutive moves. The proposed cohort measures provide a more comprehensive picture of migration behavior and should be used to complement period measures in exploring long-term trends. Increasing availability of retrospective and longitudinal survey data means that researchers can now apply the proposed measures to a wide range of countries.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.5615M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.5615M"><span>A 305 year monthly rainfall series for the Island of Ireland (1711-2016)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Murphy, Conor; Burt, Tim P.; Broderick, Ciaran; Duffy, Catriona; Macdonald, Neil; Matthews, Tom; McCarthy, Mark P.; Mullan, Donal; Noone, Simon; Ryan, Ciara; Thorne, Peter; Walsh, Seamus; Wilby, Robert L.</p> <p>2017-04-01</p> <p>This paper derives a continuous 305-year monthly rainfall series for the Island of Ireland (IoI) for the period 1711-2016. Two key data sources are employed: i) a previously unpublished UK Met Office Note which compiled annual rainfall anomalies and corresponding monthly per mille amounts from weather diaries and early observational records for the period 1711-1977; and ii) a long-term, homogenised monthly IoI rainfall series for the period 1850-2016. Using estimates of long-term average precipitation sampled from the quality assured series, the full record is reconstituted and insights drawn regarding notable periods and the range of climate variability and change experienced. Consistency with other long records for the region is examined, including: the England and Wales Precipitation series (EWP; 1766-2016); the early EWP Glasspoole series (1716-1765) and the Central England Temperature series (CET; 1711-2016). Strong correspondence between all records is noted from 1780 onwards. While disparities are evident between the early EWP and Ireland series, the latter shows strong decadal consistency with CET throughout the record. In addition, independent, early observations from Cork and Dublin, along with available documentary sources, corroborate the derived series and add confidence to our reconstruction. The new IoI rainfall record reveals that the wettest decades occurred in the early 18th Century, despite the fact that IoI has experienced a long-term winter wetting trend consistent with climate model projections. These exceptionally wet winters of the 1720s and 1730s were concurrent with almost unprecedented warmth in the CET, glacial advance throughout Scandinavia, and glacial retreat in West Greenland, consistent with a wintertime NAO-type forcing. Our study therefore demonstrates the value of long-term observational records for providing insight to the natural climate variability of the North Atlantic region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoRL..44.7900G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoRL..44.7900G"><span>Assessing the climate-scale variability of atmospheric rivers affecting western North America</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gershunov, Alexander; Shulgina, Tamara; Ralph, F. Martin; Lavers, David A.; Rutz, Jonathan J.</p> <p>2017-08-01</p> <p>A new method for automatic detection of atmospheric rivers (ARs) is developed and applied to an atmospheric reanalysis, yielding an extensive catalog of ARs land-falling along the west coast of North America during 1948-2017. This catalog provides a large array of variables that can be used to examine AR cases and their climate-scale variability in exceptional detail. The new record of AR activity, as presented, validated and examined here, provides a perspective on the seasonal cycle and the interannual-interdecadal variability of AR activity affecting the hydroclimate of western North America. Importantly, AR intensity does not exactly follow the climatological pattern of AR frequency. Strong links to hydroclimate are demonstrated using a high-resolution precipitation data set. We describe the seasonal progression of AR activity and diagnose linkages with climate variability expressed in Pacific sea surface temperatures, revealing links to Pacific decadal variability, recent regional anomalies, as well as a generally rising trend in land-falling AR activity. The latter trend is consistent with a long-term increase in vapor transport from the warming North Pacific onto the North American continent. The new catalog provides unprecedented opportunities to study the climate-scale behavior and predictability of ARs affecting western North America.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1330303-long-term-variability-sugarcane-bagasse-feedstock-compositional-methods-sources-magnitude-analytical-variability','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1330303-long-term-variability-sugarcane-bagasse-feedstock-compositional-methods-sources-magnitude-analytical-variability"><span>Long-term variability in sugarcane bagasse feedstock compositional methods: Sources and magnitude of analytical variability</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Templeton, David W.; Sluiter, Justin B.; Sluiter, Amie; ...</p> <p>2016-10-18</p> <p>In an effort to find economical, carbon-neutral transportation fuels, biomass feedstock compositional analysis methods are used to monitor, compare, and improve biofuel conversion processes. These methods are empirical, and the analytical variability seen in the feedstock compositional data propagates into variability in the conversion yields, component balances, mass balances, and ultimately the minimum ethanol selling price (MESP). We report the average composition and standard deviations of 119 individually extracted National Institute of Standards and Technology (NIST) bagasse [Reference Material (RM) 8491] run by seven analysts over 7 years. Two additional datasets, using bulk-extracted bagasse (containing 58 and 291 replicates each),more » were examined to separate out the effects of batch, analyst, sugar recovery standard calculation method, and extractions from the total analytical variability seen in the individually extracted dataset. We believe this is the world's largest NIST bagasse compositional analysis dataset and it provides unique insight into the long-term analytical variability. Understanding the long-term variability of the feedstock analysis will help determine the minimum difference that can be detected in yield, mass balance, and efficiency calculations. The long-term data show consistent bagasse component values through time and by different analysts. This suggests that the standard compositional analysis methods were performed consistently and that the bagasse RM itself remained unchanged during this time period. The long-term variability seen here is generally higher than short-term variabilities. It is worth noting that the effect of short-term or long-term feedstock compositional variability on MESP is small, about $0.03 per gallon. The long-term analysis variabilities reported here are plausible minimum values for these methods, though not necessarily average or expected variabilities. We must emphasize the importance of training and good analytical procedures needed to generate this data. As a result, when combined with a robust QA/QC oversight protocol, these empirical methods can be relied upon to generate high-quality data over a long period of time.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1330303','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1330303"><span>Long-term variability in sugarcane bagasse feedstock compositional methods: Sources and magnitude of analytical variability</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Templeton, David W.; Sluiter, Justin B.; Sluiter, Amie</p> <p></p> <p>In an effort to find economical, carbon-neutral transportation fuels, biomass feedstock compositional analysis methods are used to monitor, compare, and improve biofuel conversion processes. These methods are empirical, and the analytical variability seen in the feedstock compositional data propagates into variability in the conversion yields, component balances, mass balances, and ultimately the minimum ethanol selling price (MESP). We report the average composition and standard deviations of 119 individually extracted National Institute of Standards and Technology (NIST) bagasse [Reference Material (RM) 8491] run by seven analysts over 7 years. Two additional datasets, using bulk-extracted bagasse (containing 58 and 291 replicates each),more » were examined to separate out the effects of batch, analyst, sugar recovery standard calculation method, and extractions from the total analytical variability seen in the individually extracted dataset. We believe this is the world's largest NIST bagasse compositional analysis dataset and it provides unique insight into the long-term analytical variability. Understanding the long-term variability of the feedstock analysis will help determine the minimum difference that can be detected in yield, mass balance, and efficiency calculations. The long-term data show consistent bagasse component values through time and by different analysts. This suggests that the standard compositional analysis methods were performed consistently and that the bagasse RM itself remained unchanged during this time period. The long-term variability seen here is generally higher than short-term variabilities. It is worth noting that the effect of short-term or long-term feedstock compositional variability on MESP is small, about $0.03 per gallon. The long-term analysis variabilities reported here are plausible minimum values for these methods, though not necessarily average or expected variabilities. We must emphasize the importance of training and good analytical procedures needed to generate this data. As a result, when combined with a robust QA/QC oversight protocol, these empirical methods can be relied upon to generate high-quality data over a long period of time.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3543486','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3543486"><span>Recreational physical activity and risk of papillary thyroid cancer among women in the California Teachers Study</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Cash, Stephanie Whisnant; Ma, Huiyan; Horn-Ross, Pamela L.; Reynolds, Peggy; Canchola, Alison J.; Sullivan-Halley, Jane; Beresford, Shirley A.A.; Neuhouser, Marian L.; Vaughan, Thomas L.; Heagerty, Patrick J.; Bernstein, Leslie</p> <p>2012-01-01</p> <p>Purpose Little is known about the relationship between physical activity and thyroid cancer risk, and few cohort data on this association exist. Thus, the present study aimed to prospectively examine long-term activity and risk of papillary thyroid cancer among women. Methods 116,939 women in the California Teachers Study, aged 22 to 79 years with no history of thyroid cancer at cohort entry, were followed from 1995-1996 through 2009; 275 were diagnosed with invasive papillary thyroid cancer. Cox proportional-hazards regression provided relative risk (RR) estimates and 95% confidence intervals (CI) for associations between thyroid cancer and combined strenuous and moderate recreational physical activity both in the long-term (high school through age 54 years or current age if younger than 54 years) and recently (during the three years prior to joining the cohort). Results Overall, women whose long-term recreational physical activity averaged at least 5.5 MET-hours/week (i.e. were active) had a non-significant 23% lower risk of papillary thyroid cancer than inactive women (RR=0.77, 95% CI: 0.57, 1.04). RR estimates were stronger among normal weight or underweight women (body mass index, BMI<25.0 kg/m2, trend p=0.03) than among overweight or obese women (trend p=0.35; homogeneity-of-trends p=0.03). A similar pattern of risk was observed for recent activity (BMI<25 kg/m2, trend p=0.11; BMI≥25 kg/m2, trend p=0.16; homogeneity-of-trends p=0.04). Associations for long-term activity did not appear to be driven by activity in any particular life period (e.g. youth, adulthood). Conclusions Long-term physical activity may reduce papillary thyroid cancer risk among normal weight and underweight women. PMID:23116823</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=314893','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=314893"><span>Long-term trends in climate and hydrology in an agricultural headwater watershed of central Pennsylvania, USA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Climate change has emerged as a key issue facing agriculture and water resources in the US. Long-term (1968-2012) temperature, precipitation and streamflow data from a small (7.3 km2) watershed in east-central Pennsylvania was used to examine climatic and hydrologic trends in the context of recent c...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMOS13A1791B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMOS13A1791B"><span>Relative Sea Level Trends Along the Coast of the Bay of Bengal</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Becker, M.; Calmant, S.; Papa, F.; Delebecque, C.; Islam, A. S.; Shum, C. K.</p> <p>2016-12-01</p> <p>In the coastal belt of the Bay of Bengal, the sea level rise is one of a major threat, linked to climate change, which drastically affects the livelihoods of millions of people. A comprehensive understanding of sea level trends and its variability in this region is therefore crucial and should help to anticipate the impacts of climate change and implement adaptation strategies. This region is bordered mostly by Bangladesh, India, Malaysia, Myanmar, and Thailand. Here, we revisit the sea level changes in the Bay of Bengal region from tide gauges and satellite altimetry over the period 1993-2014. The 23 monthly mean tide gauge records, used in this study, are retrieved from PSMSL (15 records) and supplemented with Bangladeshi observations (8 records). We show that, over the satellite altimetry era, the sea level interannual/decadal variability is mainly due to ocean thermal expansion variability driven by IOD/ENSO events and their low frequency modulation. We focus on relative sea level rise at major coastal cities and try to separate the climatic signal (long term trend plus interannual/decadal variability) from local effects, in particular vertical land movements. Results from GPS are analysed where available. When no such data exist, vertical land movements are deduced from the combined use of tide gauge and altimetry data. While the analysis is performed over the whole region, a particular attention is given to the low-lyingBangladesh's coastal area.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3166369','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3166369"><span>Trends in Mortality of Tuberculosis Patients in the United States: The Long-term Perspective</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Barnes, Richard F.W.; Moore, Maria Luisa; Garfein, Richard S.; Brodine, Stephanie; Strathdee, Steffanie A.; Rodwell, Timothy C.</p> <p>2011-01-01</p> <p>PURPOSE To describe long-term trends in TB mortality and to compare trends estimated from two different sources of public health surveillance data. METHODS Trends and changes in trend were estimated by joinpoint regression. Comparisons between datasets were made by fitting a Poisson regression model. RESULTS Since 1900, TB mortality rates estimated from death certificates have declined steeply, except for a period of no change in the 1980s. This decade had long-term consequences resulting in more TB deaths in later years than would have occurred had there been no flattening of the trend. Recent trends in TB mortality estimated from National Tuberculosis Surveillance System (NTSS) data, which record all-cause mortality, differed from trends based on death certificates. In particular, NTSS data showed TB mortality rates flattening since 2002. CONCLUSIONS Estimates of trends in TB mortality vary by data source, and therefore interpretation of the success of control efforts will depend upon the surveillance dataset used. The datasets may be subject to different biases that vary with time. One dataset showed a sustained improvement in the control of TB since the early 1990s while the other indicated that the rate of TB mortality was no longer declining. PMID:21820320</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.9150C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.9150C"><span>Long-term variability of UV irradiance over Northern Eurasia according to satellite measurements, ERA-INTERIM dataset and INM-RSHU chemical climate model</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chubarova, Nataly; Pastukhova, Anna; Zhdanova, Ekaterina; Khlestova, Julia; Poliukhov, Alexei; Smyshlyaev, Sergei; Galin, Vener</p> <p>2017-04-01</p> <p>We present the results of long-term erythemal UV irradiance (ERY) changes over the territory of Northern Eurasia according to the ERA-INTERIM reanalysis dataset, INM-RSHU chemical climate model (CCM), and TOMS and OMI satellite data with the correction on absorbing aerosol based on the new Macv2 climatology updated from Kinne et al. (2013) over the 1979-2015 period. We show the existence of the pronounced positive ERY trend due to ozone in spring and summer over Europe and over the central areas of Siberia (up 3% over the decade). The changes in cloud cover provide even more significant ERY increase (up to 6-8% per decade). However, over Arctic region there is a pronounced negative ERY trend probably due to the effects of melting ice on global circulation processes. The combination of ozone and cloud effects provides the enhanced increase of the overall ERY trend: up to 6-9% in spring and summer over Eastern Europe, some regions of Siberia and the Far East. In addition, based on the method described in (Chubarova, Zhdanova, 2013) we estimated changes in UV resources over Northern Eurasia since 1979. We show that for the first skin type there is a significant geographical shift of UV categories: the increase in the UV optimum area in winter, where the vitamin D generation is possible without risk of getting sunburn, and its reducing in other months due to decrease in ozone and clouds. We also analyze the long-term UV changes simulated according to different scenarios using the INM-RSHU CCM. There is a general agreement between CCM and observational datasets, however, ERY trends due to cloudiness do not correspond sometimes in space and are smaller. We show that the positive ERY trend due to ozone is determined by the anthropogenic emissions of halogens. The variations in natural factors (solar activity and ocean surface temperature, stratospheric aerosol) only provide the increase in ERY dispersion. References: Kinne, S., O'Donnel D., Stier P., et al., J. Adv. Model. Earth Syst., 5, 704-740, 2013. Chubarova N., Zhdanova Ye. Photochemistry and Photobiology. - 2013. - Vol. 127. - P. 38-51.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150022177','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150022177"><span>Long-Term Trends in Space-Ground Atmospheric Propagation Measurements</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zemba, Michael J.; Nessel, James A.; Morse, Jacquelynne R.</p> <p>2015-01-01</p> <p>Propagation measurement campaigns are critical to characterizing the atmospheric behavior of a location and efficiently designing space-ground links. However, as global climate change affects weather patterns, the long-term trends of propagation data may be impacted over periods of decades or longer. Particularly, at high microwave frequencies (10 GHz and above), rain plays a dominant role in the attenuation statistics, and it has been observed that rain events over the past 50 years have trended toward increased frequency, intensity, and rain height. In the interest of quantifying the impact of these phenomena on long-term trends in propagation data, this paper compares two 20 GHz measurement campaigns both conducted at NASAs White Sands facility in New Mexico. The first is from the Advanced Communications Technology Satellite (ACTS) propagation campaign from 1994 to 1998, while the second is amplitude data recorded during a site test interferometer (STI) phase characterization campaign from 2009 to 2014.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160001361','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160001361"><span>Long-Term Trends in Space-Ground Atmospheric Propagation Measurements</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zemba, Michael J.; Morse, Jacquelynne R.; Nessel, James A.</p> <p>2015-01-01</p> <p>Propagation measurement campaigns are critical to characterizing the atmospheric behavior of a location and efficiently designing space-ground links. However, as global climate change affects weather patterns, the long-term trends of propagation data may be impacted over periods of decades or longer. Particularly, at high microwave frequencies (10 GHz and above), rain plays a dominant role in the attenuation statistics, and it has been observed that rain events over the past 50 years have trended toward increased frequency, intensity, and rain height. In the interest of quantifying the impact of these phenomena on long-term trends in propagation data, this paper compares two 20 GHz measurement campaigns both conducted at NASA's White Sands facility in New Mexico. The first is from the Advanced Communication Technology Satellite (ACTS) propagation campaign from 1994 - 1998, while the second is amplitude data recorded during a site test interferometer (STI) phase characterization campaign from 2009 - 2014.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70037567','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70037567"><span>Analysis of the Arctic system for freshwater cycle intensification: Observations and expectations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Rawlins, M.A.; Steele, M.; Holland, M.M.; Adam, J.C.; Cherry, J.E.; Francis, J.A.; Groisman, P.Y.; Hinzman, L.D.; Huntington, T.G.; Kane, D.L.; Kimball, J.S.; Kwok, R.; Lammers, R.B.; Lee, C.M.; Lettenmaier, D.P.; McDonald, K.C.; Podest, E.; Pundsack, J.W.; Rudels, B.; Serreze, Mark C.; Shiklomanov, A.; Skagseth, O.; Troy, T.J.; Vorosmarty, C.J.; Wensnahan, M.; Wood, E.F.; Woodgate, R.; Yang, D.; Zhang, K.; Zhang, T.</p> <p>2010-01-01</p> <p>Hydrologic cycle intensification is an expected manifestation of a warming climate. Although positive trends in several global average quantities have been reported, no previous studies have documented broad intensification across elements of the Arctic freshwater cycle (FWC). In this study, the authors examine the character and quantitative significance of changes in annual precipitation, evapotranspiration, and river discharge across the terrestrial pan-Arctic over the past several decades from observations and a suite of coupled general circulation models (GCMs). Trends in freshwater flux and storage derived from observations across the Arctic Ocean and surrounding seas are also described. With few exceptions, precipitation, evapotranspiration, and river discharge fluxes from observations and the GCMs exhibit positive trends. Significant positive trends above the 90% confidence level, however, are not present for all of the observations. Greater confidence in the GCM trends arises through lower interannual variability relative to trend magnitude. Put another way, intrinsic variability in the observations tends to limit confidence in trend robustness. Ocean fluxes are less certain, primarily because of the lack of long-term observations. Where available, salinity and volume flux data suggest some decrease in saltwater inflow to the Barents Sea (i.e., a decrease in freshwater outflow) in recent decades. A decline in freshwater storage across the central Arctic Ocean and suggestions that large-scale circulation plays a dominant role in freshwater trends raise questions as to whether Arctic Ocean freshwater flows are intensifying. Although oceanic fluxes of freshwater are highly variable and consistent trends are difficult to verify, the other components of the Arctic FWC do show consistent positive trends over recent decades. The broad-scale increases provide evidence that the Arctic FWC is experiencing intensification. Efforts that aim to develop an adequate observation system are needed to reduce uncertainties and to detect and document ongoing changes in all system components for further evidence of Arctic FWC intensification.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.C51C1000N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.C51C1000N"><span>Analyzing Snowpack Metrics Over Large Spatial Extents Using Calibrated, Enhanced-Resolution Brightness Temperature Data and Long Short Term Memory Artificial Neural Networks</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Norris, W.; J Q Farmer, C.</p> <p>2017-12-01</p> <p>Snow water equivalence (SWE) is a difficult metric to measure accurately over large spatial extents; snow-tell sites are too localized, and traditional remotely sensed brightness temperature data is at too coarse of a resolution to capture variation. The new Calibrated Enhanced-Resolution Brightness Temperature (CETB) data from the National Snow and Ice Data Center (NSIDC) offers remotely sensed brightness temperature data at an enhanced resolution of 3.125 km versus the original 25 km, which allows for large spatial extents to be analyzed with reduced uncertainty compared to the 25km product. While the 25km brightness temperature data has proved useful in past research — one group found decreasing trends in SWE outweighed increasing trends three to one in North America; other researchers used the data to incorporate winter conditions, like snow cover, into ecological zoning criterion — with the new 3.125 km data, it is possible to derive more accurate metrics for SWE, since we have far more spatial variability in measurements. Even with higher resolution data, using the 37 - 19 GHz frequencies to estimate SWE distorts the data during times of melt onset and accumulation onset. Past researchers employed statistical splines, while other successful attempts utilized non-parametric curve fitting to smooth out spikes distorting metrics. In this work, rather than using legacy curve fitting techniques, a Long Short Term Memory (LSTM) Artificial Neural Network (ANN) was trained to perform curve fitting on the data. LSTM ANN have shown great promise in modeling time series data, and with almost 40 years of data available — 14,235 days — there is plenty of training data for the ANN. LSTM's are ideal for this type of time series analysis because they allow important trends to persist for long periods of time, but ignore short term fluctuations; since LSTM's have poor mid- to short-term memory, they are ideal for smoothing out the large spikes generated in the melt and accumulation onset seasons, while still capturing the overall trends in the data.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.B52A..03P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.B52A..03P"><span>Recent trends in Inner Asian forest dynamics to temperature and precipitation indicate high sensitivity to climate change</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poulter, B.; Pederson, N.; Liu, H.; Zhu, Z.; D'Arrigo, R.; Ciais, P.; Davi, N.; Frank, D. C.; Leland, C.; Myneni, R.; Piao, S.; Wang, T.</p> <p>2012-12-01</p> <p>Semi-arid ecosystems play an important role in regulating global climate and their response to climate change will depend on interactions between temperature, precipitation, and CO2. However, in cool-arid environments, precipitation is not the only limitation to forest productivity. For example, interactions between changes in precipitation and air temperature may enhance soil moisture stress while simultaneously extending growing season length, with unclear consequences for net carbon uptake. This presentation evaluates recent trends in productivity and seasonality of forests located in Inner Asia (Mongolia and Northern China) using satellite remote sensing, dendrochronology, and dynamic global vegetation model (DGVM) simulations to quantify the sensitivity of forest dynamics to decadal climate variability and trends. Long-term trends from satellite observations of FPAR between 1982-2010 show a greening of 21% of the region in spring (March, April May), but with 10% of the area 'browning' during summertime (June, July, August), the results of which are corroborated by trends in NPP simulated by the LPJ DGVM. Spring greening trends in FPAR are mainly explained by long-term trends in precipitation whereas summer browning trends are correlated with decreasing precipitation. Tree ring data from 25 sites confirm annual growth increments are mainly limited by summer precipitation (June, July, August) in Mongolia, and spring precipitation in northern China (March, April, May), with relatively weak prior-year lag effects. An ensemble of climate projections from the IPCC CMIP3 models indicates that warming temperatures (spring, summer) are expected to be associated with higher summer precipitation, which combined with CO2 causes large increases in NPP and eventual increase in forest cover in the Mongolian steppe. In the absence of a strong direct CO2 fertilization effect on plant growth (e.g., due to nutrient limitation), water stress or decreased carbon gain from higher autotrophic respiration results in decreased productivity and loss of forest cover.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.C14B..07T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.C14B..07T"><span>Spaceborne estimated long-term trends (1980s - 2013) of albedo and melting season length over the Greenland ice sheet and linkages to climate drivers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tedesco, M.; Stroeve, J. C.</p> <p>2014-12-01</p> <p>The length of the melting season and surface albedo modulate the amount of meltwater produced over the Greenland ice sheet. The two quantities are intimately connected through a suite of non-linear processes: for example, early melting can reduce the surface albedo (through constructive grain size metamorphism), hence affecting the surface energy balance and further increasing melting. Over the past years, several studies have highlighted increased melting concurring, with a decrease of mean surface albedo over Greenland. However, few studies have examined the duration of the melting season, its implication for surface processes and linkages to climate drivers. Moreover, the majority (if not all) of the studies assessing albedo trends from spaceborne data over Greenland have focused on the last decade or so (2000 - 2013) because they use data collected over the same period by the Moderate Resolution Imaging Spectroradiometer (MODIS). Here, we evaluate and synthesize long-term trends in the length of the melting season (1979 - 2013) derived from spaceborne microwave observations together with surface albedo trends for the period 1982 - 2013 using data from the Advanced Very High Resolution Radiometer (AVHRR). To our knowledge, this is the first time that trends in Greenland albedo and melt season length are discussed for the periods considered in this study. Our results point to a lengthening of the melting season as a consequence of earlier melt onset and later refreeze and to a decrease of mean albedo (1982 - 2013) over the Greenland ice sheet, with trends being spatially variable. To account for this spatial variability, the results of an analysis at regional scales over 12 different regions (defined by elevation and drainage systems) are also reported. The robustness of the results is evaluated by means of a comparative analysis of the results obtained from both AVHRR and MODIS when overlapping data are available (2000 - 2013). Lastly, because large-scale circulation patterns and climate drivers can impact the amount of meltwater produced over Greenland (hence impacting albedo), we discuss the observed trends in the context of North Atlantic Oscillation (NAO) and Greenland Blocking Index (GBI) using a combination of regional climate model outputs and re-analysis data.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70024832','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70024832"><span>Problems in evaluating regional and local trends in temperature: An example from eastern Colorado, USA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Pielke, R.A.; Stohlgren, T.; Schell, L.; Parton, W.; Doesken, N.; Redmond, K.; Moeny, J.; McKee, T.; Kittel, T.G.F.</p> <p>2002-01-01</p> <p>We evaluated long-term trends in average maximum and minimum temperatures, threshold temperatures, and growing season in eastern Colorado, USA, to explore the potential shortcomings of many climate-change studies that either: (1) generalize regional patterns from single stations, single seasons, or a few parameters over short duration from averaging dissimilar stations: or (2) generalize an average regional pattern from coarse-scale general circulation models. Based on 11 weather stations, some trends were weakly regionally consistent with previous studies of night-time temperature warming. Long-term (80 + years) mean minimum temperatures increased significantly (P < 0.2) in about half the stations in winter, spring, and autumn and six stations had significant decreases in the number of days per year with temperatures ??? - 17.8 ??C (???0??F). However, spatial and temporal variation in the direction of change was enormous for all the other weather parameters tested, and, in the majority of tests, few stations showed significant trends (even at P < 0.2). In summer, four stations had significant increases and three stations had significant decreases in minimum temperatures, producing a strongly mixed regional signal. Trends in maximum temperature varied seasonally and geographically, as did trends in threshold temperature days ???32.2??C (???90??F) or days ???37.8??C (???100??F). There was evidence of a subregional cooling in autumn's maximum temperatures, with five stations showing significant decreasing trends. There were many geographic anomalies where neighbouring weather stations differed greatly in the magnitude of change or where they had significant and opposite trends. We conclude that sub-regional spatial and seasonal variation cannot be ignored when evaluating the direction and magnitude of climate change. It is unlikely that one or a few weather stations are representative of regional climate trends, and equally unlikely that regionally projected climate change from coarse-scale general circulation models will accurately portray trends at sub-regional scales. However, the assessment of a group of stations for consistent more qualitative trends (such as the number of days less than - 17.8??C, such as we found) provides a reasonably robust procedure to evaluate climate trends and variability. Copyright ?? 2002 Royal Meteorological Society.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1915271B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1915271B"><span>Where is PM gone? Trends and variability of atmospheric PM10, PM2.5 and PM10-2.5 in the Po valley over the last decade (and more).</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bigi, Alessandro; Ghermandi, Grazia</p> <p>2017-04-01</p> <p>The Po Valley is one of the largest European regions with a remarkably high concentration level of atmospheric pollutants, both for particulate and gaseous compounds. In the last decade stringent regulations on air quality standards and on anthropogenic emissions have been set by the European Commission, leading to an overall improvement in air quality across Europe. In order to assess the decadal pattern and variability in PM across the Po valley we thoroughly investigated the time series of PM10, PM2.5 and PM10-2.5 from 41, 44 and 15 sites respectively (Bigi & Ghermandi 2014, 2016). PM2.5 and PM10-2.5 (PM10) series with a 7 (10) year or longer record have been analysed for long term trend in deseasonalized monthly means, annual quantiles and in monthly frequency distribution by robust statistical methods. A widespread and significant decreasing trend was observed at several sites for all size fractions, with the drop, up to a few percent per year, occurring mainly in winter for PM2.5 and throughout the year for PM10. All series were tested for a significant weekly periodicity (a proxy to estimate the impact of primary anthropogenic emissions) by 3 different statistical methods, yielding positive results for summer PM2.5 and PM10, and for both summer and winter PM10-2.5. Hierarchical cluster analysis showed larger variability for PM10 than for PM2.5. The former was split in five clusters: two encompassing the metropolitan areas of Turin and Milan and their respective nearby sites and the other three clusters gathering northeast, northwest and central Po Valley sites respectively. PM2.5 clusters divide the valley in western, eastern and southern/Apennines foothill sectors. The trend in atmospheric concentration was compared with the time series of local primary and precursor emissions, vehicular fleet details and fuel sales. A significant basin-wide drop in emissions occurred for gaseous pollutants, contrarily to primary emissions of PM10 and PM2.5, whose drop was low and spatially restricted. Overall the decrease in atmospheric PM2.5 and PM10 seems to originate from a drop in both primary emissions and in precursors of secondary inorganic aerosol emissions, largely ascribed to vehicular traffic. Potentially, the recent increase in biomass burning emissions in winter and the modest decrease in NH3 weaken an otherwise even larger drop in atmospheric concentrations. References Bigi, A. & Ghermandi, G. Long-term trend and variability of atmospheric PM10 concentration in the Po Valley Atmospheric Chemistry and Physics, 2014, 14, 4895-4907 Bigi, A. & Ghermandi, G. Trends and variability of atmospheric PM2.5 and PM10-2.5 concentration in the Po Valley, Italy Atmospheric Chemistry and Physics, 2016, 16, 15777-15788</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/5678591-subalpine-tree-growth-climate-increasing-co-sub-assessment-recent-growth-trends-pinus-balfouriana-murrayana-juniperus-occidentalis','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5678591-subalpine-tree-growth-climate-increasing-co-sub-assessment-recent-growth-trends-pinus-balfouriana-murrayana-juniperus-occidentalis"><span>Subalpine tree growth, climate, and increasing CO sub 2 : An assessment of recent growth trends. [Pinus balfouriana; P. murrayana; Juniperus occidentalis</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Graumlich, L.J.</p> <p>1991-02-01</p> <p>Five tree-ring series from foxtail pine (Pinus balfouriana), lodgepole pine (P. murrayana), and western juniper (Juniperus occidentalis) collected in the Sierra Nevada, California, were analyzed to determine if the temporal and spatial patterns of recent growth were consistent with the hypothesized CO{sub 2}-induced growth enhancement. Specifically, the author addresses the following questions: (1) can growth trends be explained solely in terms of climatic variation; (2) are recent growth trends unusual with respect to long-term growth records While the results offer no support for the hypothesized CO{sub 2} fertilization effect, they do provide insights into the response of subalpine conifers tomore » climatic variation. Response surfaces demonstrate that precipitation during previous winter and temperature during the current summer interact in controlling growth and that the response can be nonlinear. Although maximum growth rates occur under conditions of high winter precipitation and warm summers for all three species, substantial species-to-species variation occurs in the response to these two variables.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H51J1337Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H51J1337Y"><span>Detecting Long-term Trend of Water Quality Indices of Dong-gang River, Taiwan Using Quantile Regression</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, D.; Shiau, J.</p> <p>2013-12-01</p> <p>ABSTRACT BODY: Abstract Surface water quality is an essential issue in water-supply for human uses and sustaining healthy ecosystem of rivers. However, water quality of rivers is easily influenced by anthropogenic activities such as urban development and wastewater disposal. Long-term monitoring of water quality can assess whether water quality of rivers deteriorates or not. Taiwan is a population-dense area and heavily depends on surface water for domestic, industrial, and agricultural uses. Dong-gang River is one of major resources in southern Taiwan for agricultural requirements. The water-quality data of four monitoring stations of the Dong-gang River for the period of 2000-2012 are selected for trend analysis. The parameters used to characterize water quality of rivers include biochemical oxygen demand (BOD), dissolved oxygen (DO), suspended solids (SS), and ammonia nitrogen (NH3-N). These four water-quality parameters are integrated into an index called river pollution index (RPI) to indicate the pollution level of rivers. Although widely used non-parametric Mann-Kendall test and linear regression exhibit computational efficiency to identify trends of water-quality indices, limitations of such approaches include sensitive to outliers and estimations of conditional mean only. Quantile regression, capable of identifying changes over time of any percentile values, is employed in this study to detect long-term trend of water-quality indices for the Dong-gang River located in southern Taiwan. The results show that Dong-gang River 4 stations from 2000 to 2012 monthly long-term trends in water quality.To analyze s Dong-gang River long-term water quality trends and pollution characteristics. The results showed that the bridge measuring ammonia Long-dong, BOD5 measure in that station on a downward trend, DO, and SS is on the rise, River Pollution Index (RPI) on a downward trend. The results form Chau-Jhou station also ahowed simialar trends .more and more near the upstrean Hing-she station raise vivestok Sing-She stations are that ammonia on a upward trend, BOD5 no significant change in trend, DO, and SS is on the rise, river pollution index (RPI) a slight downward trend. Dong-gang River Basin , but the progress of sewer construction in slow. To reduce pollation in this river effort shoul be made regulatory reform on livestock waste control and acceleration of sewer construction. Keywords: quantile regression analysis, BOD5, RPI</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ARMS....9..125M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ARMS....9..125M"><span>Natural Variability and Anthropogenic Trends in the Ocean Carbon Sink</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McKinley, Galen A.; Fay, Amanda R.; Lovenduski, Nicole S.; Pilcher, Darren J.</p> <p>2017-01-01</p> <p>Since preindustrial times, the ocean has removed from the atmosphere 41% of the carbon emitted by human industrial activities. Despite significant uncertainties, the balance of evidence indicates that the globally integrated rate of ocean carbon uptake is increasing in response to increasing atmospheric CO2 concentrations. The El Niño-Southern Oscillation in the equatorial Pacific dominates interannual variability of the globally integrated sink. Modes of climate variability in high latitudes are correlated with variability in regional carbon sinks, but mechanistic understanding is incomplete. Regional sink variability, combined with sparse sampling, means that the growing oceanic sink cannot yet be directly detected from available surface data. Accurate and precise shipboard observations need to be continued and increasingly complemented with autonomous observations. These data, together with a variety of mechanistic and diagnostic models, are needed for better understanding, long-term monitoring, and future projections of this critical climate regulation service.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H11E1394E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H11E1394E"><span>Sensitivity of intermittent streams to climate variations in the United States</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eng, K.</p> <p>2015-12-01</p> <p>There is growing interest in the effects of climate change on streamflows because of the potential negative effects on aquatic biota and water supplies. Previous studies of climate controls on flows have primarily focused on perennial streams, and few studies have examined the effect of climate variability on intermittent streams. Our objectives in this study were to (1) identify regions showing similar patterns of intermittency, and (2) evaluate the sensitivity of intermittent streams to historical variability in climate in the United States. This study was carried out at 265 intermittent streams by evaluating: (1) correlations among time series of flow metrics (number of zero-flow events, the average of the central 50% and largest 10% of flows) with precipitation (magnitudes, durations and intensity) and temperature, and (2) decadal changes in the seasonality and long-term trends of these flow metrics. Results identified five distinct seasonal patterns of flow intermittency: fall, fall-to-winter, non-seasonal, summer, and summer-to-winter intermittent streams. In addition, strong associations between the low-flow metrics and historical climate variability were found. However, the lack of trends in historical variations in precipitation results in no significant seasonal shifts or decade-to-decade trends in the low-flow metrics over the period of record (1950 to 2013).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/13537','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/13537"><span>Hardwood stumpage price trends in New England</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>D.F. Dennis; P.E. Sendak</p> <p>1991-01-01</p> <p>Stumpage price trends in New Hampshire and Vermont varied considerably among species and products. Real stumpage price trends, expressed in 1988 dollars using the Producer Price Index to remove the effect of inflation, are reported for selected species and products. Long-term (1964-1989) trends in average annual prices are reported for New Hampshire and short-term (...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016QSRv..144...44N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016QSRv..144...44N"><span>Long-term changes in pigmentation of arctic Daphnia provide potential for reconstructing aquatic UV exposure</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nevalainen, Liisa; Rantala, Marttiina V.; Luoto, Tomi P.; Ojala, Antti E. K.; Rautio, Milla</p> <p>2016-07-01</p> <p>Despite the biologically damaging impacts of solar ultraviolet radiation (UV) in nature, little is known about its natural variability, forcing mechanisms, and long-term effects on ecosystems and organisms. Arctic zooplankton, for example the aquatic keystone genus Daphnia (Crustacea, Cladocera) responds to biologically damaging UV by utilizing photoprotective strategies, including pigmentation. We examined the preservation and content of UV-screening pigments in fossil Daphnia remains (ephippia) in two arctic lake sediment cores from Cornwallis Island (Lake R1), Canada, and Spitsbergen (Lake Fugledammen), Svalbard. The aims were to document changes in the degree of UV-protective pigmentation throughout the past centuries, elucidate the adaptive responses of zooplankton to long-term variations in UV exposure, and estimate the potential of fossil zooplankton pigments in reconstructing aquatic UV regimes. The spectroscopic absorbance measurements of fossil Daphnia ephippia under UV (280-400 nm) and visible light (400-700 nm) spectral ranges indicated that melanin (absorbance maxima at UV wavebands 280-350 nm) and carotenoids (absorbance maxima at 400-450 nm) pigments were preserved in the ephippia in both sediment cores. Downcore measurements of the most important UV-protective pigment melanin (absorbance measured at 305 and 340 nm) showed marked long-term variations in the degree of melanisation. These variations likely represented long-term trends in aquatic UV exposure and were positively related with solar radiation intensity. The corresponding trends in melanisation and solar activity were disrupted at the turn of the 20th century in R1, but remained as strong in Fugledammen. The reversed trends in the R1 core were simultaneous with a significant aquatic community reorganization taking place in the lake, suggesting that recent environmental changes, likely related to climate warming had a local effect on pigmentation strategies. This time horizon is also concurrent with previously recorded major ecological shifts in circumpolar lakes when human induced changes in ecological processes of sensitive arctic ecosystems started to occur. The current centennial record of UV-induced melanisation of sedimentary Daphnia ephippia presents unique reference material for assessing UV impacts in arctic aquatic ecosystems before human influence and during the 20th century climate change and provides potential for assessing past aquatic UV regimes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70023572','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70023572"><span>Eruptive stratigraphy of the Tatara-San Pedro complex, 36°S, sourthern volcanic zone, Chilean Andes: reconstruction method and implications for magma evolution at long-lived arc volcanic centers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dungan, M.A.; Wulff, A.; Thompson, R.</p> <p>2001-01-01</p> <p>The Quaternary Tatara-San Pedro volcanic complex (36°S, Chilean Andes) comprises eight or more unconformity-bound volcanic sequences, representing variably preserved erosional remnants of volcanic centers generated during 930 ky of activity. The internal eruptive histories of several dominantly mafic to intermediate sequences have been reconstructed, on the basis of correlations of whole-rock major and trace element chemistry of flows between multiple sampled sections, but with critical contributions from photogrammetric, geochronologic, and paleomagnetic data. Many groups of flows representing discrete eruptive events define internal variation trends that reflect extrusion of heterogeneous or rapidly evolving magna batches from conduit-reservoir systems in which open-system processes typically played a large role. Long-term progressive evolution trends are extremely rare and the magma compositions of successive eruptive events rarely lie on precisely the same differentiation trend, even where they have evolved from similar parent magmas by similar processes. These observations are not consistent with magma differentiation in large long-lived reservoirs, but they may be accommodated by diverse interactions between newly arrived magma inputs and multiple resident pockets of evolved magma and / or crystal mush residing in conduit-dominated subvolcanic reservoirs. Without constraints provided by the reconstructed stratigraphic relations, the framework for petrologic modeling would be far different. A well-established eruptive stratigraphy may provide independent constraints on the petrologic processes involved in magma evolution-simply on the basis of the specific order in which diverse, broadly cogenetic magmas have been erupted. The Tatara-San Pedro complex includes lavas ranging from primitive basalt to high-SiO2 rhyolite, and although the dominant erupted magma type was basaltic andesite ( 52-55 wt % SiO2) each sequence is characterized by unique proportions of mafic, intermediate, and silicic eruptive products. Intermediate lava compositions also record different evolution paths, both within and between sequences. No systematic long-term pattern is evident from comparisons at the level of sequences. The considerable diversity of mafic and evolved magmas of the Tatara-San Pedro complex bears on interpretations of regional geochemical trends. The variable role of open-system processes in shaping the compositions of evolved Tatara-San Pedro complex magmas, and even some basaltic magmas, leads to the conclusion that addressing problems such as are magma genesis and elemental fluxes through subduction zones on the basis of averaged or regressed reconnaissance geochemical datasets is a tenuous exercise. Such compositional indices are highly instructive for identifying broad regional trends and first-order problems, but they should be used with extreme caution in attempts to quantify processes and magma sources, including crustal components, implicated in these trends.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950031248&hterms=balance+general&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dbalance%2Bgeneral','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950031248&hterms=balance+general&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dbalance%2Bgeneral"><span>Climatology and natural variability of the global hydrologic cycle in the GLA atmospheric general circulation model</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lau, K.-M.; Mehta, V. M.; Sud, Y. C.; Walker, G. K.</p> <p>1994-01-01</p> <p>Time average climatology and low-frequency variabilities of the global hydrologic cycle (GHC) in the Goddard Laboratory for Atmospheres (GLA) general circulation model (GCM) were investigated in the present work. A 730-day experiment was conducted with the GLA GCM forced by insolation, sea surface temperature, and ice-snow undergoing climatological annual cycles. Ifluences of interactive soil moisture on time average climatology and natural variability of the GHC were also investigated by conducting 365-day experiments with and without interactive soil moisture. Insolation, sea surface temperature, and ice-snow were fixed at their July levels in the latter two experiments. Results show that the model's time average hydrologic cycle variables for July in all three experiments agree reasonably well with observations. Except in the case of precipitable water, the zonal average climates of the annual cycle experiment and the two perpetual July experiments are alike, i.e., their differences are within limits of the natural variability of the model's climate. Statistics of various components of the GHC, i.e., water vapor, evaporation, and precipitation, are significantly affected by the presence of interactive soil moisture. A long-term trend is found in the principal empirical modes of variability of ground wetness, evaporation, and sensible heat. Dominant modes of variability of these quantities over land are physically consistent with one another and with land surface energy balance requirements. The dominant mode of precipitation variability is found to be closely related to organized convection over the tropical western Pacific Ocean. The precipitation variability has timescales in the range of 2 to 3 months and can be identified with the stationary component of the Madden-Julian Oscillation. The precipitation mode is not sensitive to the presence of interactive soil moisture but is closely linked to both the rotational and divergent components of atmospheric moisture transport. The present results indicate that globally coherent natural variability of the GHC in the GLA GCM has two basic timescales in the absence of annual cycles of external forcings: a long-term trend associated with atmosphere-soil moisture interaction which affects the model atmosphere mostly over midlatitude continental regions and a large-scale 2- to 3-month variability associated with atmospheric moist processes over the western Pacific Ocean.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25253209','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25253209"><span>Forecasting Japanese encephalitis incidence from historical morbidity patterns: Statistical analysis with 27 years of observation in Assam, India.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Handique, Bijoy K; Khan, Siraj A; Mahanta, J; Sudhakar, S</p> <p>2014-09-01</p> <p>Japanese encephalitis (JE) is one of the dreaded mosquito-borne viral diseases mostly prevalent in south Asian countries including India. Early warning of the disease in terms of disease intensity is crucial for taking adequate and appropriate intervention measures. The present study was carried out in Dibrugarh district in the state of Assam located in the northeastern region of India to assess the accuracy of selected forecasting methods based on historical morbidity patterns of JE incidence during the past 22 years (1985-2006). Four selected forecasting methods, viz. seasonal average (SA), seasonal adjustment with last three observations (SAT), modified method adjusting long-term and cyclic trend (MSAT), and autoregressive integrated moving average (ARIMA) have been employed to assess the accuracy of each of the forecasting methods. The forecasting methods were validated for five consecutive years from 2007-2012 and accuracy of each method has been assessed. The forecasting method utilising seasonal adjustment with long-term and cyclic trend emerged as best forecasting method among the four selected forecasting methods and outperformed the even statistically more advanced ARIMA method. Peak of the disease incidence could effectively be predicted with all the methods, but there are significant variations in magnitude of forecast errors among the selected methods. As expected, variation in forecasts at primary health centre (PHC) level is wide as compared to that of district level forecasts. The study showed that adopted forecasting techniques could reasonably forecast the intensity of JE cases at PHC level without considering the external variables. The results indicate that the understanding of long-term and cyclic trend of the disease intensity will improve the accuracy of the forecasts, but there is a need for making the forecast models more robust to explain sudden variation in the disease intensity with detail analysis of parasite and host population dynamics.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010107843','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010107843"><span>Continuation of the NVAP Global Water Vapor Data Sets for Pathfinder Science Analysis</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>VonderHaar, Thomas H.; Engelen, Richard J.; Forsythe, John M.; Randel, David L.; Ruston, Benjamin C.; Woo, Shannon; Dodge, James (Technical Monitor)</p> <p>2001-01-01</p> <p>This annual report covers August 2000 - August 2001 under NASA contract NASW-0032, entitled "Continuation of the NVAP (NASA's Water Vapor Project) Global Water Vapor Data Sets for Pathfinder Science Analysis". NASA has created a list of Earth Science Research Questions which are outlined by Asrar, et al. Particularly relevant to NVAP are the following questions: (a) How are global precipitation, evaporation, and the cycling of water changing? (b) What trends in atmospheric constituents and solar radiation are driving global climate? (c) How well can long-term climatic trends be assessed or predicted? Water vapor is a key greenhouse gas, and an understanding of its behavior is essential in global climate studies. Therefore, NVAP plays a key role in addressing the above climate questions by creating a long-term global water vapor dataset and by updating the dataset with recent advances in satellite instrumentation. The NVAP dataset produced from 1988-1998 has found wide use in the scientific community. Studies of interannual variability are particularly important. A recent paper by Simpson, et al. that examined the NVAP dataset in detail has shown that its relative accuracy is sufficient for the variability studies that contribute toward meeting NASA's goals. In the past year, we have made steady progress towards continuing production of this high-quality dataset as well as performing our own investigations of the data. This report summarizes the past year's work on production of the NVAP dataset and presents results of analyses we have performed in the past year.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21135964','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21135964"><span>The effect of changes to the method of estimating the pollen count from aerobiological samples.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sikoparija, Branko; Pejak-Šikoparija, Tatjana; Radišić, Predrag; Smith, Matt; Soldevilla, Carmen Galán</p> <p>2011-02-01</p> <p>Pollen data have been recorded at Novi Sad in Serbia since 2000. The adopted method of producing pollen counts has been the use of five longitudinal transects that examine 19.64% of total sample surface. However, counting five transects is time consuming and so the main objective of this study is to investigate whether reducing the number to three or even two transects would have a significant effect on daily average and bi-hourly pollen concentrations, as well as the main characteristics of the pollen season and long-term trends. This study has shown that there is a loss of accuracy in daily average and bi-hourly pollen concentrations (an increase in % ERROR) as the sub-sampling area is reduced from five to three or two longitudinal transects. However, this loss of accuracy does not impact on the main characteristics of the season or long-term trends. As a result, this study can be used to justify changing the sub-sampling method used at Novi Sad from five to three longitudinal transects. The use of two longitudinal transects has been ruled out because, although quicker, the counts produced: (a) had the greatest amount of % ERROR, (b) altered the amount of influence of the independent variable on the dependent variable (the slope in regression analysis) and (c) the total sampled surface (7.86%) was less than the minimum requirement recommended by the European Aerobiology Society working group on Quality Control (at least 10% of total slide area).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70173458','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70173458"><span>Spatial and temporal Brook Trout density dynamics: Implications for conservation, management, and monitoring</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wagner, Tyler; Jefferson T. Deweber,; Jason Detar,; Kristine, David; John A. Sweka,</p> <p>2014-01-01</p> <p>Many potential stressors to aquatic environments operate over large spatial scales, prompting the need to assess and monitor both site-specific and regional dynamics of fish populations. We used hierarchical Bayesian models to evaluate the spatial and temporal variability in density and capture probability of age-1 and older Brook Trout Salvelinus fontinalis from three-pass removal data collected at 291 sites over a 37-year time period (1975–2011) in Pennsylvania streams. There was high between-year variability in density, with annual posterior means ranging from 2.1 to 10.2 fish/100 m2; however, there was no significant long-term linear trend. Brook Trout density was positively correlated with elevation and negatively correlated with percent developed land use in the network catchment. Probability of capture did not vary substantially across sites or years but was negatively correlated with mean stream width. Because of the low spatiotemporal variation in capture probability and a strong correlation between first-pass CPUE (catch/min) and three-pass removal density estimates, the use of an abundance index based on first-pass CPUE could represent a cost-effective alternative to conducting multiple-pass removal sampling for some Brook Trout monitoring and assessment objectives. Single-pass indices may be particularly relevant for monitoring objectives that do not require precise site-specific estimates, such as regional monitoring programs that are designed to detect long-term linear trends in density.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/37488-long-term-trends-ddt-pcbs-chlordane-mussels-from-california','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/37488-long-term-trends-ddt-pcbs-chlordane-mussels-from-california"><span>Long-term trends in DDT, PCBs, and chlordane in mussels from California</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Stephenson, M.D.; Tjeerdema, R.S.</p> <p>1994-12-31</p> <p>Many contaminant programs have been established to study the geographical distributions and long-term trends of potential pollutants, but unfortunately, many have been short-lived because of economic cutbacks, providing limited information on long-term trends. The California State Mussel Watch program, however, has been continuously funded for the past 15 years. Several sites have been evaluated and were sampled often enough to obtain statistical resolution. Chlordane was evaluated at 29 stations, with 48% showing significant decreases over time; DDT was evaluated at 35 sites, with 43% showing significant declines; and PCBs were evaluated at 47 sites, with 21% showing significant drops overmore » time. Both DDT and PCBs showed declines, corresponding to decreases in their concentrations in the effluent, at sites located in the vicinity of the Los Angeles County municipal sewage outfall. This long-term investigation indicates that, contrary to public opinion, the banning of DDT, chlordane, and PCBs by the USEPA has led to overall improvement in water quality.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.sciencedirect.com/science/article/pii/S0140196311001492','USGSPUBS'); return false;" href="http://www.sciencedirect.com/science/article/pii/S0140196311001492"><span>A comparison of methods to assess long-term changes in Sonoran Desert vegetation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Munson, S.M.; Webb, R.H.; Hubbard, J.A.</p> <p>2011-01-01</p> <p>Knowledge about the condition of vegetation cover and composition is critical for assessing the structure and function of ecosystems. To effectively quantify the impacts of a rapidly changing environment, methods to track long-term trends of vegetation must be precise, repeatable, and time- and cost-efficient. Measuring vegetation cover and composition in arid and semiarid regions is especially challenging because vegetation is typically sparse, discontinuous, and individual plants are widely spaced. To meet the goal of long-term vegetation monitoring in the Sonoran Desert and other arid and semiarid regions, we determined how estimates of plant species, total vegetation, and soil cover obtained using a widely-implemented monitoring protocol compared to a more time- and resource-intensive plant census. We also assessed how well this protocol tracked changes in cover through 82 years compared to the plant census. Results from the monitoring protocol were comparable to those from the plant census, despite low and variable plant species cover. Importantly, this monitoring protocol could be used as a rapid, "off-the shelf" tool for assessing land degradation (or desertification) in arid and semiarid ecosystems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70046804','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70046804"><span>Analysis options for estimating status and trends in long-term monitoring</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bart, Jonathan; Beyer, Hawthorne L.</p> <p>2012-01-01</p> <p>This chapter describes methods for estimating long-term trends in ecological parameters. Other chapters in this volume discuss more advanced methods for analyzing monitoring data, but these methods may be relatively inaccessible to some readers. Therefore, this chapter provides an introduction to trend analysis for managers and biologists while also discussing general issues relevant to trend assessment in any long-term monitoring program. For simplicity, we focus on temporal trends in population size across years. We refer to the survey results for each year as the “annual means” (e.g. mean per transect, per plot, per time period). The methods apply with little or no modification, however, to formal estimates of population size, other temporal units (e.g. a month), to spatial or other dimensions such as elevation or a north–south gradient, and to other quantities such as chemical or geological parameters. The chapter primarily discusses methods for estimating population-wide parameters rather than studying variation in trend within the population, which can be examined using methods presented in other chapters (e.g. Chapters 7, 12, 20). We begin by reviewing key concepts related to trend analysis. We then describe how to evaluate potential bias in trend estimates. An overview of the statistical models used to quantify trends is then presented. We conclude by showing ways to estimate trends using simple methods that can be implemented with spreadsheets.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18765775','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18765775"><span>Temporal trends in nitrate and selected pesticides in Mid-Atlantic ground water.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Debrewer, Linda M; Ator, Scott W; Denver, Judith M</p> <p>2008-01-01</p> <p>Evaluating long-term temporal trends in regional ground-water quality is complicated by variable hydrogeologic conditions and typically slow flow, and such trends have rarely been directly measured. Ground-water samples were collected over near-decadal and annual intervals from unconfined aquifers in agricultural areas of the Mid-Atlantic region, including fractured carbonate rocks in the Great Valley, Potomac River Basin, and unconsolidated sediments on the Delmarva Peninsula. Concentrations of nitrate and selected pesticides and degradates were compared among sampling events and to apparent recharge dates. Observed temporal trends are related to changes in land use and chemical applications, and to hydrogeology and climate. Insignificant differences in nitrate concentrations in the Great Valley between 1993 and 2002 are consistent with relatively steady fertilizer application during respective recharge periods and are likely related to drought conditions in the later sampling period. Detecting trends in Great Valley ground water is complicated by long open boreholes characteristic of wells sampled in this setting which facilitate significant ground-water mixing. Decreasing atrazine and prometon concentrations, however, reflect reported changes in usage. On the Delmarva Peninsula between 1988 and 2001, median nitrate concentrations increased 2 mg per liter in aerobic ground water, reflecting increasing fertilizer applications. Correlations between selected pesticide compounds and apparent recharge date are similarly related to changing land use and chemical application. Observed trends in the two settings demonstrate the importance of considering hydrogeology and recharge date along with changing land and chemical uses when interpreting trends in regional ground-water quality.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=determinants+AND+economic+AND+growth&pg=6&id=ED331761','ERIC'); return false;" href="https://eric.ed.gov/?q=determinants+AND+economic+AND+growth&pg=6&id=ED331761"><span>Prospective Trends in the Socio-Economic Context of Education in European Market Economy Countries.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Weiss, M.; And Others</p> <p></p> <p>The purpose of this study was to project and analyze the prospective long-term trends in the socioeconomic context of the educational systems of European market economies and to outline in global terms the probable implication for education and training in the future. Composed of three chapters, the chapter 1 focuses on projected long-term…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18382001','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18382001"><span>Long-term trends in adolescent and young adult smoking in the United States: metapatterns and implications.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nelson, David E; Mowery, Paul; Asman, Kat; Pederson, Linda L; O'Malley, Patrick M; Malarcher, Ann; Maibach, Edward W; Pechacek, Terry F</p> <p>2008-05-01</p> <p>We sought to describe long-term adolescent and young adult smoking trends and patterns. We analyzed adolescent data from Monitoring the Future, 1976 to 2005, and young adult (aged 18-24 years) data from the National Health Interview Survey, 1974 to 2005, overall and in subpopulations to identify trends in current cigarette smoking prevalence. Five metapatterns emerged: we found (1) a large increase and subsequent decrease in overall smoking over the past 15 years, (2) a steep decline in smoking among Blacks through the early 1990s, (3) a gender gap reversal among older adolescents and young adults who smoked over the past 15 years, (4) similar trends in smoking for most subgroups since the early 1990s, and (5) a large decline in smoking among young adults with less than a high school education. Long-term patterns for adolescent and young adult cigarette smoking were decidedly nonlinear, and we found evidence of a cohort effect among young adults. Continued strong efforts and a long-term societal commitment to tobacco use prevention are needed, given the unprecedented declines in smoking among most subpopulations since the mid- to late 1990s.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160012552','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160012552"><span>High-Contrast Imaging of Intermediate-Mass Giants with Long-Term Radial Velocity Trends</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ryu, Tsuguru; Sato, Bun'ei; Kuzuhara, Masayuki; Narita, Norio; Takahashi, Yasuhiro; Uyama, Taichi; Kudo, Tomoyuki; Kusakabe, Nobuhiko; Hashimoto, Jun; Omiya, Masashi; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20160012552'); toggleEditAbsImage('author_20160012552_show'); toggleEditAbsImage('author_20160012552_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20160012552_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20160012552_hide"></p> <p>2016-01-01</p> <p>A radial velocity (RV) survey for intermediate-mass giants has been operated for over a decade at Okayama Astrophysical Observatory (OAO). The OAO survey has revealed that some giants show long-term linear RV accelerations (RV trends), indicating the presence of outer companions. Direct imaging observations can help clarify what objects generate these RV trends. We present the results of high-contrast imaging observations of six intermediate-mass giants with long-term RV trends using the Subaru Telescope and HiCIAO camera. We detected co-moving companions to gamma Hya B (0.61+0.12 -0.14 Stellar Mass), HD 5608 B (0.10 +/- 0.01 Stellar Mass), and HD 109272 B (0.28 +/- 0.06 Stellar Mass). For the remaining targets( Dra, 18 Del, and HD 14067) we exclude companions more massive than 30-60 M(sub Jup) at projected separations of 1''-7''. We examine whether these directly imaged companions or unidentified long-period companions can account for the RV trends observed around the six giants. We find that the Kozai mechanism can explain the high eccentricity of the inner planets Dra b, HD 5608 b, and HD 14067 b.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...825..127R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...825..127R"><span>High-contrast Imaging of Intermediate-mass Giants with Long-term Radial Velocity Trends</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ryu, Tsuguru; Sato, Bun'ei; Kuzuhara, Masayuki; Narita, Norio; Takahashi, Yasuhiro H.; Uyama, Taichi; Kudo, Tomoyuki; Kusakabe, Nobuhiko; Hashimoto, Jun; Omiya, Masashi; Harakawa, Hiroki; Abe, Lyu; Ando, Hiroyasu; Brandner, Wolfgang; Brandt, Timothy D.; Carson, Joseph C.; Currie, Thayne; Egner, Sebastian; Feldt, Markus; Goto, Miwa; Grady, Carol A.; Guyon, Olivier; Hayano, Yutaka; Hayashi, Masahiko; Hayashi, Saeko S.; Hełminiak, Krzysztof G.; Henning, Thomas; Hodapp, Klaus W.; Ida, Shigeru; Ishii, Miki; Itoh, Yoichi; Iye, Masanori; Izumiura, Hideyuki; Janson, Markus; Kambe, Eiji; Kandori, Ryo; Knapp, Gillian R.; Kokubo, Eiichiro; Kwon, Jungmi; Matsuo, Taro; Mayama, Satoshi; McElwain, Michael W.; Mede, Kyle; Miyama, Shoken; Morino, Jun-Ichi; Moro-Martin, Amaya; Nishimura, Tetsuo; Pyo, Tae-Soo; Serabyn, Eugene; Suenaga, Takuya; Suto, Hiroshi; Suzuki, Ryuji; Takami, Michihiro; Takato, Naruhisa; Takeda, Yoichi; Terada, Hiroshi; Thalmann, Christian; Turner, Edwin L.; Watanabe, Makoto; Wisniewski, John; Yamada, Toru; Yoshida, Michitoshi; Takami, Hideki; Usuda, Tomonori; Tamura, Motohide</p> <p>2016-07-01</p> <p>A radial velocity (RV) survey for intermediate-mass giants has been in operation for over a decade at Okayama Astrophysical Observatory (OAO). The OAO survey has revealed that some giants show long-term linear RV accelerations (RV trends), indicating the presence of outer companions. Direct-imaging observations can help clarify what objects generate these RV trends. We present the results of high-contrast imaging observations of six intermediate-mass giants with long-term RV trends using the Subaru Telescope and HiCIAO camera. We detected co-moving companions to γ Hya B ({0.61}-0.14+0.12{M}⊙ ), HD 5608 B (0.10+/- 0.01{M}⊙ ), and HD 109272 B (0.28+/- 0.06{M}⊙ ). For the remaining targets (ι Dra, 18 Del, and HD 14067), we exclude companions more massive than 30-60 M Jup at projected separations of 1″-7″. We examine whether these directly imaged companions or unidentified long-period companions can account for the RV trends observed around the six giants. We find that the Kozai mechanism can explain the high eccentricity of the inner planets ι Dra b, HD 5608 b, and HD 14067 b.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018A%26A...614A..34D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018A%26A...614A..34D"><span>In-depth study of long-term variability in the X-ray emission of the Be/X-ray binary system AX J0049.4-7323</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ducci, L.; Romano, P.; Malacaria, C.; Ji, L.; Bozzo, E.; Santangelo, A.</p> <p>2018-06-01</p> <p>AX J0049.4-7323 is a Be/X-ray binary in the Small Magellanic Cloud hosting a 750 s pulsar which has been observed over the last 17 years by several X-ray telescopes. Despite numerous observations, little is known about its X-ray behaviour. Therefore, we coherently analysed archival Swift, Chandra, XMM-Newton, RXTE, and INTEGRAL data, and we compared them with already published ASCA data, to study its X-ray long-term spectral and flux variability. AX J0049.4-7323 shows a high X-ray variability, spanning more than three orders of magnitudes, from L ≈ 1.6 × 1037 erg s-1 (0.3-8 keV, d = 62 kpc) down to L ≈ 8 × 1033 erg s-1. RXTE, Chandra, Swift, and ASCA observed, in addition to the expected enhancement of X-ray luminosity at periastron, flux variations by a factor of 270 with peak luminosities of ≈2.1 × 1036 erg s-1 far from periastron. These properties are difficult to reconcile with the typical long-term variability of Be/XRBs, traditionally interpreted in terms of type I and type II outbursts. The study of AX J0049.4-7323 is complemented with a spectral analysis of Swift, Chandra, and XMM-Newton data which showed a softening trend when the emission becomes fainter, and an analysis of optical/UV data collected by the UVOT telescope on board Swift. In addition, we measured a secular spin-up rate of Ṗ = (-3.00 ± 0.12) × 10-3 s day-1, which suggests that the pulsar has not yet achieved its equilibrium period. Assuming spherical accretion, we estimated an upper limit for the magnetic field strength of the pulsar of ≈3 × 1012 G.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/95738-long-term-trends-shortgrass-steppe-vegetation-during-year-period-increasing-temperatures','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/95738-long-term-trends-shortgrass-steppe-vegetation-during-year-period-increasing-temperatures"><span>Long-term trends in shortgrass steppe vegetation during a 21-year period of increasing temperatures</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Alward, R.D.; Milchunas, D.G.; Detling, J.K.</p> <p></p> <p>Long-term weather records from the Central Plains Experimental Range revealed a general warming trend in average annual temperatures from 1971 through 1991. This was largely the result of a significant increase in mean annual minimum temperature (T{sub min}). Permanently marked vegetation quadrants were monitored for much of this same period. We constructed linear correlational models to assess relationships of annual and seasonal temperature and precipitation with plant densities and aboveground net primary productivity (ANPP) within a grazing exclosure. Response variables correlated with T{sub min} included: (i) tiller densities of the dominant grass, Bouteloua gracilis, and other warm season grasses, (ii)more » forb densities and ANPP, and (iii) total ANPP. Responses correlated with T{sub max} included: (i) total basal cover and (ii) densities and ANPP of several species. Plant species diversity was correlated with spring precipitation. Some species responded to the interactive effects of spring temperatures and precipitation. This investigation suggests that shortgrass steppe vegetation may be sensitive to climate change and supports predictions that asymmetric changes in diurnal temperatures may be an important component of climate change.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AtmRe.203..261M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AtmRe.203..261M"><span>A Poisson regression approach to model monthly hail occurrence in Northern Switzerland using large-scale environmental variables</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Madonna, Erica; Ginsbourger, David; Martius, Olivia</p> <p>2018-05-01</p> <p>In Switzerland, hail regularly causes substantial damage to agriculture, cars and infrastructure, however, little is known about its long-term variability. To study the variability, the monthly number of days with hail in northern Switzerland is modeled in a regression framework using large-scale predictors derived from ERA-Interim reanalysis. The model is developed and verified using radar-based hail observations for the extended summer season (April-September) in the period 2002-2014. The seasonality of hail is explicitly modeled with a categorical predictor (month) and monthly anomalies of several large-scale predictors are used to capture the year-to-year variability. Several regression models are applied and their performance tested with respect to standard scores and cross-validation. The chosen model includes four predictors: the monthly anomaly of the two meter temperature, the monthly anomaly of the logarithm of the convective available potential energy (CAPE), the monthly anomaly of the wind shear and the month. This model well captures the intra-annual variability and slightly underestimates its inter-annual variability. The regression model is applied to the reanalysis data back in time to 1980. The resulting hail day time series shows an increase of the number of hail days per month, which is (in the model) related to an increase in temperature and CAPE. The trend corresponds to approximately 0.5 days per month per decade. The results of the regression model have been compared to two independent data sets. All data sets agree on the sign of the trend, but the trend is weaker in the other data sets.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ThApC.tmp..156L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ThApC.tmp..156L"><span>Northerly wind trends along the Portuguese marine coast since 1950</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leitão, Francisco; Relvas, Paulo; Cánovas, Fernando; Baptista, Vânia; Teodósio, Alexandra</p> <p>2018-04-01</p> <p>Wind is a marine coastal factor that is little understood but has a strong interaction with biological productivity. In this study, northerly wind trends in three regions of the Portuguese coast (Northwestern: NW, Southwestern: SW, and Southern: S) were analyzed. Two datasets with long-term (ICOADS: 1960-2010) and short-term data (Satellite: 1989-2010) were used to complement one another. The study revealed the northerly wind yearly data to be non-stationary and highly variable between years. Overall, the northerly wind intensity increased throughout the 1960s regardless of the area and dataset. Between 1960 and 2010, the northerly wind increased at a linear rate of 0.24, 0.09, and 0.15 m s-1 per decade in the NW, SW, and S coastal regions, respectively. The rate was higher in recent decades (1988-2009), with the wind intensity increasing by 0.4, 0.3, and 0.3 ms-1 per decade in the NW, SW, and S regions, respectively. Analyses of the sudden shifts showed significant increases in northerly wind intensities after 2003, 2004, and 1998 in the NW, SW, and S coast, respectively. Exceptions were found for autumn (September for short-term data), when a decrease in northerly winds was observed in recent decades, regardless of the area, and for summer, when no changes in wind trends were recorded in the NW and SW. The long-term data also showed a major increase in northerly winds in winter (January and February), which is the recruitment season for many small and medium-sized pelagic fish. The increase in the intensity of the northerly winds over the past two decades and the past half-century occurred at a higher rate than was estimated by the IPCC for the next century.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22360495','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22360495"><span>Impact of the 2005 smoke-free policy in Italy on prevalence, cessation and intensity of smoking in the overall population and by educational group.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Federico, Bruno; Mackenbach, Johan P; Eikemo, Terje A; Kunst, Anton E</p> <p>2012-09-01</p> <p>To estimate the immediate as well as the longer-term impact of the 2005 smoke-free law on smoking prevalence, cessation and intensity both in the overall population and separately by educational level. Interrupted time-series analyses of 11 cross-sectional nationally representative surveys. Italy, 1999-2010. Adults aged 20-64 years. For each year we computed the prevalence of current smoking, the quit ratio and the mean number of cigarettes smoked per day. All measures were standardized by age. Segmented linear regression analyses were performed for each smoking variable separately by sex. Among males, smoking prevalence decreased by 2.6% (P = 0.002) and smoking cessation increased by 3.3% (P = 0.006) shortly after the ban, but both measures tended to return to pre-ban values in the following years. This occurred among both highly and low-educated males. Among low-educated females, the ban was followed by a 1.6% decrease (P = 0.120) in smoking prevalence and a 4.5% increase in quit ratios (P < 0.001). However, these favourable trends reversed over the following years. Among highly educated females, trends in smoking prevalence and cessation were not altered by the ban. Among both males and females, long-term trends in the daily number of cigarettes, which were already declining well before the implementation of the policy, changed to a minor extent. The impact of the Italian smoke-free policy on smoking and inequalities in smoking was short-term. Smoke-free policies may not achieve the secondary effect of reducing smoking prevalence in the long term, and they may have limited effects on inequalities in smoking. © 2012 The Authors. Addiction © 2012 Society for the Study of Addiction.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRA..123.1396Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRA..123.1396Y"><span>Ionospheric Trend Over Wuhan During 1947-2017: Comparison Between Simulation and Observation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yue, Xinan; Hu, Lianhuan; Wei, Yong; Wan, Weixing; Ning, Baiqi</p> <p>2018-02-01</p> <p>Since Roble and Dickinson (1989), who drew the community's attention about the greenhouse gas effect on the ionosphere, huge efforts have been implemented on ionospheric climate study. However, direct comparison between observations and simulations is still rare. Recently, the Wuhan ionosonde observations were digitized and standardized through unified method back to 1947. In this study, the NCAR-TIEGCM was driven by Mauna Loa Observatory observed CO2 level and International Geomagnetic Reference Field (IGRF) geomagnetic field to simulate their effects on ionospheric long-term trend over Wuhan. Only March equinox was considered in both data analysis and simulation. Simulation results show that the CO2 and geomagnetic field have comparable effect on hmF2 trend, while geomagnetic field effect is stronger than CO2 on foF2 trend over Wuhan. Both factors result in obvious but different diurnal variations of foF2/hmF2 long-term trends. The geomagnetic field effect is nonlinear versus years since the long-term variation of geomagnetic field intensity and orientation is complex. Mean value of foF2 and hmF2 trend is (-0.0021 MHz/yr, -0.106 km/yr) and (-0.0022 MHz/yr, -0.0763 km/yr) for observation and simulation, respectively. Regarding the diurnal variation of the trend, the simulation accords well with that of observation except hmF2 results around 12 UT. Overall, good agreement between observation and simulation illustrates the good quality of Wuhan ionosonde long-term data and the validity of ancient ionosphere reconstruction based on realistic indices driving simulation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H43D1677D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H43D1677D"><span>Trend and variability in western and central Africa streamflow, and major drivers of variability between 1950 and 2005</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dieppois, B.; Sidibe, M.; Mahe, G. M.; Paturel, J. E.; Anifowose, B. A.; Lawler, D.; Amoussou, E.</p> <p>2017-12-01</p> <p>Unprecedented drought episodes that struck western and central Africa between the late 1960s and 1980s, triggered many studies investigating rainfall variability and its impacts on water resources and food production systems. However, most studies were focused at the catchment scale. In this study, we aim at investigating the key large-scale controls determining and modulating climate-river flows relationships at the subcontinental scale between 1950 and 2005. Using the first complete monthly streamflow data set (1950-2005) over western and central Africa, streamflow trend and variability are seasonally assessed at this subcontinental scale and compared to those observed in other hydroclimatic variables (precipitation, temperature and potential evapotranspiration). Long-term trends and variability in streamflow are mainly consistent with trends in rainfall. In particular, the recent post-1990s partial recovery in Sahel rainfall could have, at least partially, positively impacted river flows (e.g. the Senegal and Niger rivers). However, these relationships may have been moderated by: i) changes in land use; and ii) contributions from groundwater resources. In addition, the time-evolution of river flows is shown to be primarily driven by very strong decadal fluctuations, which can be interpreted as modulations in the baseflow, as determined using multi-temporal trend and continuous wavelet analysis. These decadal fluctuations, which are also significantly detected in rainfall, are likely related to large-scale sea-surface temperature (SST) anomaly patterns (such as the tropical Atlantic SST variability, the Atlantic Multidecadal Oscillation, the Interdecadal Pacific Oscillation and the Pacific Decadal Oscillation), which are together modulating the West African monsoon. Furthermore, influences of the catchment properties (e.g. size, vegetation and land use cover, soil properties, direction of stream flow across climate zones) on these decadal fluctuations in river flows have been examined. This study therefore aims to improve the ability of current global to regional climate models to simulate such ranges of variability and understand regional hydroclimate, as a means for improving the development of future scenarios for water resources in western and central Africa.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JASTP.163....1L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JASTP.163....1L"><span>Preface to Long-term trends in the upper atmosphere and ionosphere</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Laštovička, J.; Lübken, F.-J.</p> <p>2017-10-01</p> <p>The anthropogenic emissions of greenhouse gases influence the atmosphere at nearly all altitudes between the ground and the topside ionosphere and upper thermosphere, thus affecting not only life on the surface, but also the space-based technological systems on which we increasingly rely. This special issue deals with long-term trends in the mesosphere, thermosphere, ionosphere, and partly also in the stratosphere, which are predominantly (but not only) caused by anthropogenic factors, particularly by the increasing concentration of carbon dioxide in the atmosphere. The special issue is based on selected papers from the 9th IAGA/ICMA/SCOSTEP workshop ;Long-Term Changes and Trends in the Atmosphere; held in September 2016 in Kühlungsborn, Germany. The 10th workshop will be held in June 2018 in Hefei, China.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70034013','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70034013"><span>Population synchrony of a native fish across three Laurentian Great Lakes: Evaluating the effects of dispersal and climate</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bunnell, D.B.; Adams, J.V.; Gorman, O.T.; Madenjian, C.P.; Riley, S.C.; Roseman, E.F.; Schaeffer, J.S.</p> <p>2010-01-01</p> <p>Climate and dispersal are the two most commonly cited mechanisms to explain spatial synchrony among time series of animal populations, and climate is typically most important for fishes. Using data from 1978-2006, we quantified the spatial synchrony in recruitment and population catch-per-unit-effort (CPUE) for bloater (Coregonus hoyi) populations across lakes Superior, Michigan, and Huron. In this natural field experiment, climate was highly synchronous across lakes but the likelihood of dispersal between lakes differed. When data from all lakes were pooled, modified correlograms revealed spatial synchrony to occur up to 800 km for long-term (data not detrended) trends and up to 600 km for short-term (data detrended by the annual rate of change) trends. This large spatial synchrony more than doubles the scale previously observed in freshwater fish populations, and exceeds the scale found in most marine or estuarine populations. When analyzing the data separately for within- and between-lake pairs, spatial synchrony was always observed within lakes, up to 400 or 600 km. Conversely, between-lake synchrony did not occur among short-term trends, and for long-term trends, the scale of synchrony was highly variable. For recruit CPUE, synchrony occurred up to 600 km between both lakes Michigan and Huron (where dispersal was most likely) and lakes Michigan and Superior (where dispersal was least likely), but failed to occur between lakes Huron and Superior (where dispersal likelihood was intermediate). When considering the scale of putative bloater dispersal and genetic information from previous studies, we concluded that dispersal was likely underlying within-lake synchrony but climate was more likely underlying between-lake synchrony. The broad scale of synchrony in Great Lakes bloater populations increases their probability of extirpation, a timely message for fishery managers given current low levels of bloater abundance. ?? Springer-Verlag 2009.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/6104101-late-holocene-climate-changes-eastern-north-america-estimated-from-pollen-data','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/6104101-late-holocene-climate-changes-eastern-north-america-estimated-from-pollen-data"><span>Late holocene climate changes in eastern North America estimated from pollen data</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Gajewski, K.</p> <p></p> <p>Well-dated pollen profiles from six sites from Maine to Minnesota record vegetation changes indicative of summer temperature and annual precipitation variations over the past 2000 yr. Laminations in the sediment provide accurate time control. Multiple regression techniques were used to calculate calibration functions from a spatial network of modern pollen and climate data. When applied to the six pollen diagrams, these calibration functions yielded estimates that show a long-term trend toward lower summer temperature. Superimposed on this long-term trend are short-term fluctuations that are frequently in phase at the sites. Departures from the long-term cooling trend are positive around 1500more » yr ago (indicating relative warmth) and negative between 200 and 500 yr ago (indicating relative cold). Annual precipitation showed a slight increase at several sites during the past 1000 yr relative to the previous 1000 yr.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/9612736','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/9612736"><span>Banking: financing trends in an acquisitive health care market--focus on long-term care.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gordon, L J; Bressler, A</p> <p>1998-01-01</p> <p>This article reviews the long-term care sector of the health care industry, particularly the factors driving sector consolidation and, through the use of four transactions as a platform, discusses key credit issues and risks facing long-term care companies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70191677','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70191677"><span>Seasonality of change: Summer warming rates do not fully represent effects of climate change on lake temperatures</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Winslow, Luke; Read, Jordan S.; Hansen, Gretchen J. A.; Rose, Kevin C.; Robertson, Dale M.</p> <p>2017-01-01</p> <p>Responses in lake temperatures to climate warming have primarily been characterized using seasonal metrics of surface-water temperatures such as summertime or stratified period average temperatures. However, climate warming may not affect water temperatures equally across seasons or depths. We analyzed a long-term dataset (1981–2015) of biweekly water temperature data in six temperate lakes in Wisconsin, U.S.A. to understand (1) variability in monthly rates of surface- and deep-water warming, (2) how those rates compared to summertime average trends, and (3) if monthly heterogeneity in water temperature trends can be predicted by heterogeneity in air temperature trends. Monthly surface-water temperature warming rates varied across the open-water season, ranging from 0.013 in August to 0.073°C yr−1 in September (standard deviation [SD]: 0.025°C yr−1). Deep-water trends during summer varied less among months (SD: 0.006°C yr−1), but varied broadly among lakes (–0.056°C yr−1 to 0.035°C yr−1, SD: 0.034°C yr−1). Trends in monthly surface-water temperatures were well correlated with air temperature trends, suggesting monthly air temperature trends, for which data exist at broad scales, may be a proxy for seasonal patterns in surface-water temperature trends during the open water season in lakes similar to those studied here. Seasonally variable warming has broad implications for how ecological processes respond to climate change, because phenological events such as fish spawning and phytoplankton succession respond to specific, seasonal temperature cues.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11959763','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11959763"><span>Pregnancy and oral contraceptive use do not significantly influence outcome in long term rheumatoid arthritis.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Drossaers-Bakker, K W; Zwinderman, A H; van Zeben, D; Breedveld, F C; Hazes, J M W</p> <p>2002-05-01</p> <p>Oral contraceptives (OC) and pregnancy are known to have an influence on the risk of onset of rheumatoid arthritis (RA). Pregnancy itself has beneficial effects on the activity of the disease, with relapses post partum. It is not known, however, whether OC and pregnancies influence the ultimate outcome of RA. To explore whether OC use and pregnancies influence the 12 year outcome in RA as measured by radiological damage and disability. In a prospective inception cohort of 132 female patients with recent RA according to the 1987 American College of Rheumatology criteria-a cohort initially gathered to study the association between hormonal factors and the onset of RA-outcome was assessed in a follow up after 12 years. The outcome was evaluated in 112 (85%) women by the radiological damage of hands and feet as measured with the Sharp score modification van der Heijde (SHS), the damage of the large joints measured with the Larsen score (LS) of large joints (0-60), and the disability measured with the Health Assessment Questionnaire (HAQ). The median values of each outcome variable were calculated for several subgroups of patients stratified for OC use and pregnancies before and after onset of the disease and the tertiles of the total number of months of OC use and of pregnancies. The association of OC use and pregnancies before and after onset of the disease with the outcome variables was calculated using Spearman's rank correlation (r(s)). The combined influence of OC use and pregnancies on the SHS, LS, and HAQ at 12 years was estimated using ordinal polytomous logistic regression. The median values of the SHS, LS, and HAQ showed a trend towards less radiological joint damage and less disability in women with long term OC use and multiple pregnancies. This difference, however, was not significant, except for the HAQ score in women with three or more pregnancies in life. There was no association between pregnancies, however defined, and any parameter of RA outcome after 12 years (maximum r(s)=-0.10). The only significant correlation was found between OC use before symptom onset and the LS (r(s)=-0.22, p<0.05). The combination of hormonal variables explained no more than a maximum of 3% of the variance of the 12 year outcome as measured by the SHS. OC use and pregnancy do not significantly influence outcome in long term RA. There is, however, a trend for patients with multiple pregnancies and long term OC use to have less radiographic joint damage and a better functional level.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A54E..06X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A54E..06X"><span>Surface ozone in China: present-day distribution and long-term changes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, X.; Lin, W.; Xu, W.</p> <p>2017-12-01</p> <p>Reliable knowledge of spatio-temporal variations of surface ozone is highly needed to assess the impacts of ozone on human health, ecosystem and climate. Although regional distributions and trends of surface ozone in European and North American countries have been well characterized, little is known about the variability of surface ozone in many other countries, including China, where emissions of ozone precursors have been changing rapidly in recent decades. Here we present the first comprehensive description of present-day (2013-2017) distribution and long-term changes of surface ozone in mainland China. Recent ozone measurements from China's air quality monitoring network (AQMN) are analyzed to show present-day distributions of a few ozone exposure metrics for urban environment. Long-term measurements of ozone at six background sites, a rural site and an urban are used to study the trends of ozone in background, rural and urban air, respectively. The average levels of ozone at the AQMN sites (mainly urban) are close to those found at many European and North American sites. However, ozone at most of the sites shows very large diurnal and seasonal variations so that ozone nonattainment can occur in many cities, particularly those in the North China Plain (NCP), the south of Northeast China (NEC), the Yangtze River Delta (YRD), the Pearl River Delta (PRD), and the Sichuan Basin-Chongqing region (SCB). In all these regions, particularly in the NCP, the maximum daily 8-h average (MDA8) ozone concentration can significantly exceed the national limit (75 ppb). High annual sum of ozone means over 35 ppb (SOMO35) exist mainly in the NCP, NEC and YRD, with regional averages over 4000 ppb·d. Surface ozone has significantly increased at Waliguan (a baseline site in western China) and Shangdianzi (a background site in the NCP), and decreased in winter and spring at Longfengshan (a background site in Northeast China). No clear trend can be derived from long-term measurements of ozone at other sites. Further attention should be paid to future changes of ozone in populated regions of China. Actions are urgently needed to control ozone pollution in the NCP and YRD.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24903105','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24903105"><span>The gender gap in sickness absence: long-term trends in eight European countries.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mastekaasa, Arne</p> <p>2014-08-01</p> <p>Most studies show that women have considerably higher rates of sickness absence than men, but little is known on how the gender gap has developed over time. Data are taken from the EU Labour Force Surveys. The dependent variable is whether the respondent reports being away from work the entire reference week or not. Trends are shown from 1980 onwards. Poisson regression is used to estimate relative risks for women vs. men, with various sets of control variables. Increasing gross differences in sickness absence between women and men are found in five countries: Spain, Ireland, France, Belgium and the UK. No trend in the gender gap is found in Netherlands and Portugal, and probably even in Italy. The trends in the gender gap have been largely the same for men and women without children at home as in the population as a whole. The trends are little affected by control for detailed occupation and industry. The gender gap in sickness absence has increased in five out of eight countries. This is not due to increased labour force participation by mothers of small children, and neither can it be explained as a result of changes in how women and men are distributed across occupations or industries. © The Author 2014. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20110005519&hterms=leaves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dleaves','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20110005519&hterms=leaves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dleaves"><span>Generating Vegetation Leaf Area Index Earth System Data Record from Multiple Sensors. Part 2; Implementation, Analysis and Validation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ganguly, Sangram; Samanta, Arindam; Schull, Mitchell A.; Shabanov, Nikolay V.; Milesi, Cristina; Nemani, Ramajrushna R,; Knyazikhin, Yuri; Myneni, Ranga B.</p> <p>2008-01-01</p> <p>The evaluation of a new global monthly leaf area index (LAI) data set for the period July 1981 to December 2006 derived from AVHRR Normalized Difference Vegetation Index (NDVI) data is described. The physically based algorithm is detailed in the first of the two part series. Here, the implementation, production and evaluation of the data set are described. The data set is evaluated both by direct comparisons to ground data and indirectly through inter-comparisons with similar data sets. This indirect validation showed satisfactory agreement with existing LAI products, importantly MODIS, at a range of spatial scales, and significant correlations with key climate variables in areas where temperature and precipitation limit plant growth. The data set successfully reproduced well-documented spatio-temporal trends and inter-annual variations in vegetation activity in the northern latitudes and semi-arid tropics. Comparison with plot scale field measurements over homogeneous vegetation patches indicated a 7% underestimation when all major vegetation types are taken into account. The error in mean values obtained from distributions of AVHRR LAI and high-resolution field LAI maps for different biomes is within 0.5 LAI for six out of the ten selected sites. These validation exercises though limited by the amount of field data, and thus less than comprehensive, indicated satisfactory agreement between the LAI product and field measurements. Overall, the intercomparison with short-term LAI data sets, evaluation of long term trends with known variations in climate variables, and validation with field measurements together build confidence in the utility of this new 26 year LAI record for long term vegetation monitoring and modeling studies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29743958','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29743958"><span>Ground-based assessment of the bias and long-term stability of fourteen limb and occultation ozone profile data records.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hubert, D; Lambert, J-C; Verhoelst, T; Granville, J; Keppens, A; Baray, J-L; Cortesi, U; Degenstein, D A; Froidevaux, L; Godin-Beekmann, S; Hoppel, K W; Kyrölä, E; Leblanc, T; Lichtenberg, G; McElroy, C T; Murtagh, D; Nakane, H; Querel, R; Russell, J M; Salvador, J; Smit, H G J; Stebel, K; Steinbrecht, W; Strawbridge, K B; Stübi, R; Swart, D P J; Taha, G; Thompson, A M; Urban, J; van Gijsel, J A E; von der Gathen, P; Walker, K A; Wolfram, E; Zawodny, J M</p> <p>2016-01-01</p> <p>The ozone profile records of a large number of limb and occultation satellite instruments are widely used to address several key questions in ozone research. Further progress in some domains depends on a more detailed understanding of these data sets, especially of their long-term stability and their mutual consistency. To this end, we made a systematic assessment of fourteen limb and occultation sounders that, together, provide more than three decades of global ozone profile measurements. In particular, we considered the latest operational Level-2 records by SAGE II, SAGE III, HALOE, UARS MLS, Aura MLS, POAM II, POAM III, OSIRIS, SMR, GOMOS, MIPAS, SCIAMACHY, ACE-FTS and MAESTRO. Central to our work is a consistent and robust analysis of the comparisons against the ground-based ozonesonde and stratospheric ozone lidar networks. It allowed us to investigate, from the troposphere up to the stratopause, the following main aspects of satellite data quality: long-term stability, overall bias, and short-term variability, together with their dependence on geophysical parameters and profile representation. In addition, it permitted us to quantify the overall consistency between the ozone profilers. Generally, we found that between 20-40 km the satellite ozone measurement biases are smaller than ±5 %, the short-term variabilities are less than 5-12% and the drifts are at most ±5% decade -1 (or even ±3 % decade -1 for a few records). The agreement with ground-based data degrades somewhat towards the stratopause and especially towards the tropopause where natural variability and low ozone abundances impede a more precise analysis. In part of the stratosphere a few records deviate from the preceding general conclusions; we identified biases of 10% and more (POAM II and SCIAMACHY), markedly higher single-profile variability (SMR and SCIAMACHY), and significant long-term drifts (SCIAMACHY, OSIRIS, HALOE, and possibly GOMOS and SMR as well). Furthermore, we reflected on the repercussions of our findings for the construction, analysis and interpretation of merged data records. Most notably, the discrepancies between several recent ozone profile trend assessments can be mostly explained by instrumental drift. This clearly demonstrates the need for systematic comprehensive multi-instrument comparison analyses.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170003211','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170003211"><span>Ground-Based Assessment of the Bias and Long-Term Stability of Fourteen Limb and Occultation Ozone Profile Data Records</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hubert, D.; Lambert, J.-C.; Verhoelst, T.; Granville, J.; Keppens, A.; Baray, J.-L.; Cortesi, U.; Degenstein, D. A.; Froidevaux, L.; Godin-Beekmann, S.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20170003211'); toggleEditAbsImage('author_20170003211_show'); toggleEditAbsImage('author_20170003211_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20170003211_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20170003211_hide"></p> <p>2016-01-01</p> <p>The ozone profile records of a large number of limb and occultation satellite instruments are widely used to address several key questions in ozone research. Further progress in some domains depends on a more detailed understanding of these data sets, especially of their long-term stability and their mutual consistency. To this end, we made a systematic assessment of fourteen limb and occultation sounders that, together, provide more than three decades of global ozone profile measurements. In particular, we considered the latest operational Level-2 records by SAGE II, SAGE III, HALOE, UARS MLS, Aura MLS, POAM II, POAM III, OSIRIS, SMR, GOMOS, MIPAS, SCIAMACHY, ACE-FTS and MAESTRO. Central to our work is a consistent and robust analysis of the comparisons against the ground-based ozonesonde and stratospheric ozone lidar networks. It allowed us to investigate, from the troposphere up to the stratopause, the following main aspects of satellite data quality: long-term stability, overall bias, and short-term variability, together with their dependence on geophysical parameters and profile representation. In addition, it permitted us to quantify the overall consistency between the ozone profilers. Generally, we found that between 20-40 kilometers the satellite ozone measurement biases are smaller than plus or minus 5 percent, the short-term variabilities are less than 5-12 percent and the drifts are at most plus or minus 5 percent per decade (or even plus or minus 3 percent per decade for a few records). The agreement with ground-based data degrades somewhat towards the stratopause and especially towards the tropopause where natural variability and low ozone abundances impede a more precise analysis. In part of the stratosphere a few records deviate from the preceding general conclusions; we identified biases of 10 percent and more (POAM II and SCIAMACHY), markedly higher single-profile variability (SMR and SCIAMACHY), and significant long-term drifts (SCIAMACHY, OSIRIS, HALOE, and possibly GOMOS and SMR as well). Furthermore, we reflected on the repercussions of our findings for the construction, analysis and interpretation of merged data records. Most notably, the discrepancies between several recent ozone profile trend assessments can be mostly explained by instrumental drift. This clearly demonstrates the need for systematic comprehensive multi-instrument comparison analyses.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5937289','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5937289"><span>Ground-based assessment of the bias and long-term stability of fourteen limb and occultation ozone profile data records</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hubert, D.; Lambert, J.-C.; Verhoelst, T.; Granville, J.; Keppens, A.; Baray, J.-L.; Cortesi, U.; Degenstein, D. A.; Froidevaux, L.; Godin-Beekmann, S.; Hoppel, K. W.; Kyrölä, E.; Leblanc, T.; Lichtenberg, G.; McElroy, C. T.; Murtagh, D.; Nakane, H.; Querel, R.; Russell, J. M.; Salvador, J.; Smit, H. G. J.; Stebel, K.; Steinbrecht, W.; Strawbridge, K. B.; Stübi, R.; Swart, D. P. J.; Taha, G.; Thompson, A. M.; Urban, J.; van Gijsel, J. A. E.; von der Gathen, P.; Walker, K. A.; Wolfram, E.; Zawodny, J. M.</p> <p>2018-01-01</p> <p>The ozone profile records of a large number of limb and occultation satellite instruments are widely used to address several key questions in ozone research. Further progress in some domains depends on a more detailed understanding of these data sets, especially of their long-term stability and their mutual consistency. To this end, we made a systematic assessment of fourteen limb and occultation sounders that, together, provide more than three decades of global ozone profile measurements. In particular, we considered the latest operational Level-2 records by SAGE II, SAGE III, HALOE, UARS MLS, Aura MLS, POAM II, POAM III, OSIRIS, SMR, GOMOS, MIPAS, SCIAMACHY, ACE-FTS and MAESTRO. Central to our work is a consistent and robust analysis of the comparisons against the ground-based ozonesonde and stratospheric ozone lidar networks. It allowed us to investigate, from the troposphere up to the stratopause, the following main aspects of satellite data quality: long-term stability, overall bias, and short-term variability, together with their dependence on geophysical parameters and profile representation. In addition, it permitted us to quantify the overall consistency between the ozone profilers. Generally, we found that between 20–40 km the satellite ozone measurement biases are smaller than ±5 %, the short-term variabilities are less than 5–12% and the drifts are at most ±5% decade−1 (or even ±3 % decade−1 for a few records). The agreement with ground-based data degrades somewhat towards the stratopause and especially towards the tropopause where natural variability and low ozone abundances impede a more precise analysis. In part of the stratosphere a few records deviate from the preceding general conclusions; we identified biases of 10% and more (POAM II and SCIAMACHY), markedly higher single-profile variability (SMR and SCIAMACHY), and significant long-term drifts (SCIAMACHY, OSIRIS, HALOE, and possibly GOMOS and SMR as well). Furthermore, we reflected on the repercussions of our findings for the construction, analysis and interpretation of merged data records. Most notably, the discrepancies between several recent ozone profile trend assessments can be mostly explained by instrumental drift. This clearly demonstrates the need for systematic comprehensive multi-instrument comparison analyses. PMID:29743958</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMEP31D..01G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMEP31D..01G"><span>Increasing Influence of Societal Response Variables in Coastal Evolution Projections (Invited)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gayes, P. T.; McCoy, C. A.; Pietrafesa, L. J.</p> <p>2010-12-01</p> <p>Recent efforts to project changes in coastal erosion and vulnerability of the state of South Carolina’s (SC’s) oceanfront for different scenarios of future sea level have reinforced the significance of the influence of societal modifications and response to past and anticipated coastal change in these systems. For large reaches of the SC coast human interactions have been a dominant signal driving coastal change across annual to decadal scales. Over the last 20 years, SC’s shoreline has been advanced seawards in many areas due to a combination of sustained societal commitment to beach nourishment and to a lull in atmospheric storms; reversing the long-term erosional trend of shoreline change. Adjacent areas not yet threatened or where coastal defense is unsupported economically have continued to migrate landwards. Locally, efforts focused on stabilizing the subaerial beach have not moderated long-term shoreward migration of the shoreface changing the overall morphology of the coastal boundary waves and currents are operating against. These societal effects, coupled with realistic, substative assessments of future atmospheric storm activity and sea level variability, both over scales of seasons to multi-decades, require consideration to realistically project future coastal behavior across time and spatial scales for planning and resource management. As with future climate and sea level variability effects on the shoreline, the scale and intensity of societal response is not static or precisely projected spatially and temporally into the future. With continued expansion of coastal development and erosion into previously lightly developed and defended coastal areas, societal influences should be expected to increase. Increasing cost of larger scale defenses will likely drive pressure for hardened structures to enhance ”softer” nourishment strategies. However, this strategy would further modify the ability of nature to respond to natural forces. Nourishment programs are strongly cyclic and can act in or out of phase with natural cyclic (inlet migration, sea level variability) or stochastic (storms) drivers with significant effects on coastal response and predictions of coastal behavior. Economic cycles and events may similarly moderate timing and scale of coastal defense relative to natural drivers. Societal decisions to not, enhance and or even abandon and remove existing engineering structures as future forces and costs increase, can result in a disproportional response and potentially failure of a section of coast. Some communities have expressed confidence in the ability to maintain the oceanfront shoreline against most projections of sea level rise over the next 100 years. The long-term trend in sea level change may be less important than naturally occurring regional scale, seasonal to inter-annual to multi-decadal variability in sea level; and these are complex but deterministic. There is less confidence, however, in the ability to combat passive submergence and associated flooding issues behind the immediate oceanfront. To the extent that may influence commitment to defend the oceanfront could strongly influence coastal behavior and stability in the long term.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.9819F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.9819F"><span>Temporal variability of total cloud cover at a Mediterranean megacity in the 20th century: Evidence from visual observations and climate models</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Founda, Dimitra; Giannakopoulos, Christos; Pierros, Fragiskos</p> <p>2013-04-01</p> <p>Cloud cover is one of the major factors that determine the radiation budget and the climate system of the Earth. Moreover, the response of clouds has always been an important source of uncertainty in global climate models. Visual surface observations of clouds have been conducted at the National Observatory of Athens (NOA) since the mid 19th century. The historical archive of cloud reports at NOA since 1860 has been digitized and updated, spanning now a period of one and a half century. Mean monthly values of total cloud cover were derived by averaging subdaily observations of cloud cover (3 observations/day). Changes in observational practice (e.g. from 1/10 to 1/8 units) were considered, however, subjective measures of cloud cover from trained observers introduces some kind of uncertainty in the time series. Data before 1884 were considered unreliable, so the analysis was restricted to the series from 1884 to 2012. The time series of total cloud cover at NOA is validated and correlated with historical time series of other (physically related) variables such as the total sunshine duration as well as DTR (Diurnal Temperature Range) which are independently measured. Trend analysis was performed on the mean annual and seasonal series of total cloud cover from 1884-2012. The mean annual values show a marked temporal variability with sub periods of decreasing and increasing tendencies, however, the overall linear trend is positive and statistically significant (p <0.001) amounting to +2% per decade and implying a total increase of almost 25% for the whole analysed period. These results are in agreement qualitatively with the trends reported in other studies worldwide, especially concerning the period before the mid 20th century. On a seasonal basis, spring and summer series present outstanding positive long term trends, while in winter and autumn total cloud cover reveals also positive but less pronounced long term trends Additionally, an evaluation of cloud cover and/or sunshine duration/diurnal temperature range as depicted by regional climate models over Athens will be performed. Regional climate models are valuable tools for projections of future climate change but their performance is typically assessed only in terms of temperature and precipitation. The representation of non-standard parameters such as cloud cover and/or sunshine duration/diurnal temperature range has so far seen little or no evaluation in the models and can therefore be prone to large uncertainties. Regional climate models developed in the framework of recent EU projects, such as the ENSEMBLES (www.ensembles-eu.org) and the CIRCE (www.circeproject.eu) projects, will be used and an initial validation of these parameters against the historical archive of NOA will be performed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ACP....18..705T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ACP....18..705T"><span>Drivers for spatial, temporal and long-term trends in atmospheric ammonia and ammonium in the UK</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tang, Yuk S.; Braban, Christine F.; Dragosits, Ulrike; Dore, Anthony J.; Simmons, Ivan; van Dijk, Netty; Poskitt, Janet; Dos Santos Pereira, Gloria; Keenan, Patrick O.; Conolly, Christopher; Vincent, Keith; Smith, Rognvald I.; Heal, Mathew R.; Sutton, Mark A.</p> <p>2018-01-01</p> <p>A unique long-term dataset from the UK National Ammonia Monitoring Network (NAMN) is used here to assess spatial, seasonal and long-term variability in atmospheric ammonia (NH3: 1998-2014) and particulate ammonium (NH4+: 1999-2014) across the UK. Extensive spatial heterogeneity in NH3 concentrations is observed, with lowest annual mean concentrations at remote sites (< 0.2 µg m-3) and highest in the areas with intensive agriculture (up to 22 µg m-3), while NH4+ concentrations show less spatial variability (e.g. range of 0.14 to 1.8 µg m-3 annual mean in 2005). Temporally, NH3 concentrations are influenced by environmental conditions and local emission sources. In particular, peak NH3 concentrations are observed in summer at background sites (defined by 5 km grid average NH3 emissions < 1 kg N ha-1 yr-1) and in areas dominated by sheep farming, driven by increased volatilization of NH3 in warmer summer temperatures. In areas where cattle, pig and poultry farming is dominant, the largest NH3 concentrations are in spring and autumn, matching periods of manure application to fields. By contrast, peak concentrations of NH4+ aerosol occur in spring, associated with long-range transboundary sources. An estimated decrease in NH3 emissions by 16 % between 1998 and 2014 was reported by the UK National Atmospheric Emissions Inventory. Annually averaged NH3 data from NAMN sites operational over the same period (n = 59) show an indicative downward trend, although the reduction in NH3 concentrations is smaller and non-significant: Mann-Kendall (MK), -6.3 %; linear regression (LR), -3.1 %. In areas dominated by pig and poultry farming, a significant reduction in NH3 concentrations between 1998 and 2014 (MK: -22 %; LR: -21 %, annually averaged NH3) is consistent with, but not as large as the decrease in estimated NH3 emissions from this sector over the same period (-39 %). By contrast, in cattle-dominated areas there is a slight upward trend (non-significant) in NH3 concentrations (MK: +12 %; LR: +3.6 %, annually averaged NH3), despite the estimated decline in NH3 emissions from this sector since 1998 (-11 %). At background and sheep-dominated sites, NH3 concentrations increased over the monitoring period. These increases (non-significant) at background (MK: +17 %; LR: +13 %, annually averaged data) and sheep-dominated sites (MK: +15 %; LR: +19 %, annually averaged data) would be consistent with the concomitant reduction in SO2 emissions over the same period, leading to a longer atmospheric lifetime of NH3, thereby increasing NH3 concentrations in remote areas. The observations for NH3 concentrations not decreasing as fast as estimated emission trends are consistent with a larger downward trend in annual particulate NH4+ concentrations (1999-2014: MK: -47 %; LR: -49 %, p < 0.01, n = 23), associated with a lower formation of particulate NH4+ in the atmosphere from gas phase NH3.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ESD.....8..337H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ESD.....8..337H"><span>Prevailing climatic trends and runoff response from Hindukush-Karakoram-Himalaya, upper Indus Basin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hasson, Shabeh ul; Böhner, Jürgen; Lucarini, Valerio</p> <p>2017-05-01</p> <p>Largely depending on the meltwater from the Hindukush-Karakoram-Himalaya, withdrawals from the upper Indus Basin (UIB) contribute half of the surface water availability in Pakistan, indispensable for agricultural production systems, industrial and domestic use, and hydropower generation. Despite such importance, a comprehensive assessment of prevailing state of relevant climatic variables determining the water availability is largely missing. Against this background, this study assesses the trends in maximum, minimum and mean temperatures, diurnal temperature range and precipitation from 18 stations (1250-4500 m a.s.l.) for their overlapping period of record (1995-2012) and, separately, from six stations of their long-term record (1961-2012). For this, a Mann-Kendall test on serially independent time series is applied to detect the existence of a trend, while its true slope is estimated using the Sen's slope method. Further, locally identified climatic trends are statistically assessed for their spatial-scale significance within 10 identified subregions of the UIB, and the spatially (field-) significant climatic trends are then qualitatively compared with the trends in discharge out of corresponding subregions. Over the recent period (1995-2012), we find warming and drying of spring (field-significant in March) and increasing early melt season discharge from most of the subregions, likely due to a rapid snowmelt. In stark contrast, most of the subregions feature a field-significant cooling within the monsoon period (particularly in July and September), which coincides well with the main glacier melt season. Hence, a decreasing or weakly increasing discharge is observed from the corresponding subregions during mid- to late melt season (particularly in July). Such tendencies, being largely consistent with the long-term trends (1961-2012), most likely indicate dominance of the nival but suppression of the glacial melt regime, altering overall hydrology of the UIB in future. These findings, though constrained by sparse and short observations, largely contribute in understanding the UIB melt runoff dynamics and address the hydroclimatic explanation of the <q>Karakoram Anomaly</q>.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5734650','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5734650"><span>Vertical structure of stratospheric water vapour trends derived from merged satellite data</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hegglin, M. I.; Plummer, D. A.; Shepherd, T. G.; Scinocca, J. F.; Anderson, J.; Froidevaux, L.; Funke, B.; Hurst, D.; Rozanov, A.; Urban, J.; von Clarmann, T.; Walker, K. A.; Wang, H. J.; Tegtmeier, S.; Weigel, K.</p> <p>2017-01-01</p> <p>Stratospheric water vapour is a powerful greenhouse gas. The longest available record from balloon observations over Boulder, Colorado, USA shows increases in stratospheric water vapour concentrations that cannot be fully explained by observed changes in the main drivers, tropical tropopause temperatures and methane. Satellite observations could help resolve the issue, but constructing a reliable long-term data record from individual short satellite records is challenging. Here we present an approach to merge satellite data sets with the help of a chemistry-climate model nudged to observed meteorology. We use the models' water vapour as a transfer function between data sets that overcomes issues arising from instrument drift and short overlap periods. In the lower stratosphere, our water vapour record extends back to 1988 and water vapour concentrations largely follow tropical tropopause temperatures. Lower and mid-stratospheric long-term trends are negative, and the trends from Boulder are shown not to be globally representative. In the upper stratosphere, our record extends back to 1986 and shows positive long-term trends. The altitudinal differences in the trends are explained by methane oxidation together with a strengthened lower-stratospheric and a weakened upper-stratospheric circulation inferred by this analysis. Our results call into question previous estimates of surface radiative forcing based on presumed global long-term increases in water vapour concentrations in the lower stratosphere. PMID:29263751</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29263751','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29263751"><span>Vertical structure of stratospheric water vapour trends derived from merged satellite data.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hegglin, M I; Plummer, D A; Shepherd, T G; Scinocca, J F; Anderson, J; Froidevaux, L; Funke, B; Hurst, D; Rozanov, A; Urban, J; von Clarmann, T; Walker, K A; Wang, H J; Tegtmeier, S; Weigel, K</p> <p>2014-01-01</p> <p>Stratospheric water vapour is a powerful greenhouse gas. The longest available record from balloon observations over Boulder, Colorado, USA shows increases in stratospheric water vapour concentrations that cannot be fully explained by observed changes in the main drivers, tropical tropopause temperatures and methane. Satellite observations could help resolve the issue, but constructing a reliable long-term data record from individual short satellite records is challenging. Here we present an approach to merge satellite data sets with the help of a chemistry-climate model nudged to observed meteorology. We use the models' water vapour as a transfer function between data sets that overcomes issues arising from instrument drift and short overlap periods. In the lower stratosphere, our water vapour record extends back to 1988 and water vapour concentrations largely follow tropical tropopause temperatures. Lower and mid-stratospheric long-term trends are negative, and the trends from Boulder are shown not to be globally representative. In the upper stratosphere, our record extends back to 1986 and shows positive long-term trends. The altitudinal differences in the trends are explained by methane oxidation together with a strengthened lower-stratospheric and a weakened upper-stratospheric circulation inferred by this analysis. Our results call into question previous estimates of surface radiative forcing based on presumed global long-term increases in water vapour concentrations in the lower stratosphere.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhyA..415..449K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhyA..415..449K"><span>Evolutionary model of stock markets</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaldasch, Joachim</p> <p>2014-12-01</p> <p>The paper presents an evolutionary economic model for the price evolution of stocks. Treating a stock market as a self-organized system governed by a fast purchase process and slow variations of demand and supply the model suggests that the short term price distribution has the form a logistic (Laplace) distribution. The long term return can be described by Laplace-Gaussian mixture distributions. The long term mean price evolution is governed by a Walrus equation, which can be transformed into a replicator equation. This allows quantifying the evolutionary price competition between stocks. The theory suggests that stock prices scaled by the price over all stocks can be used to investigate long-term trends in a Fisher-Pry plot. The price competition that follows from the model is illustrated by examining the empirical long-term price trends of two stocks.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28697945','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28697945"><span>Dynamic hydrographic variations in northwestern Arabian Gulf over the past three decades: Temporal shifts and trends derived from long-term monitoring data.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Al-Yamani, Faiza; Yamamoto, Takahiro; Al-Said, Turki; Alghunaim, Aws</p> <p>2017-09-15</p> <p>Hydrographic variables were monitored in northwestern Arabian Gulf over the past three decades and the time-series data were statistically analyzed. The results show that while salinity has undergone several shifts, seawater temperature exhibited a steady increasing trend since the 1980s. The observed salinity shows strong correlation with Shatt Al-Arab River discharge indicating primary contribution of freshwater to salinity among other factors (evaporation and desalination effluent). Recent data show that salinity is at its highest level in the last 30years with less pronounced seasonal variability in response to severe decline in the freshwater runoff into the northwestern Arabian Gulf. The changes in hydrographic conditions may have significant implications on hydrodynamics, water quality, and ecosystems in the Gulf. Thus, cooperation among the concerned countries - both coastal and riparian nations - would be essential for prevention of further major changes in the Gulf. Copyright © 2017 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2011/3084/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2011/3084/"><span>Response of lake chemistry to atmospheric deposition and climate in selected Class I wilderness areas in the western United States, 1993-2009</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Mast, M. Alisa</p> <p>2011-01-01</p> <p>The U.S. Geological Survey, in cooperation with the U.S. Department of Agriculture Forest Service, Air Resource Management, conducted a study to evaluate long-term trends in lake-water chemistry for 64 high-elevation lakes in selected Class I wilderness areas in Colorado, Idaho, Utah, and Wyoming during 1993 to 2009. Understanding how and why lake chemistry is changing in mountain areas is essential for effectively managing and protecting high-elevation aquatic ecosystems. Trends in emissions, atmospheric deposition, and climate variables (air temperature and precipitation amount) were evaluated over a similar period of record. A main objective of the study was to determine if changes in atmospheric deposition of contaminants in the Rocky Mountain region have resulted in measurable changes in the chemistry of high-elevation lakes. A second objective was to investigate linkages between lake chemistry and air temperature and precipitation to improve understanding of the sensitivity of mountain lakes to climate variability.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.2301L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.2301L"><span>Long-term trend of foE in European higher middle latitudes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Laštovička, Jan</p> <p>2016-04-01</p> <p>Long-term changes and trends have been observed in the whole ionosphere below its maximum. As concerns the E region, historical global data (Bremer, 2008) provide predominantly slightly positive trend, even though some stations provide a negative trend. Here we use data of two European stations with the best long data series of parameters of the ionospheric E layer, Slough/Chilton and Juliusruh over 1975-2014 (40 years). Noon-time medians (10-14 LT) are analyzed. The trend pattern after removing solar influence is complex. For yearly average values for Chilton first foE is decreasing in 1975-1990 by about 0.1 MHz, then the trend levels off or a little increase occurs in 1990-2004, and finally in 2004-2014 again a decrease is observed (again by about 0.1 MHz but over shorter period). Juliusruh yields a similar pattern. Similar analysis is also done for some months to check seasonal dependence of trends. The stability of relation between solar activity and foE is tested to clarify potential role of this factor in apparent trend of foE.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/47943','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/47943"><span>Using nestling plasma to assess long-term spatial and temporal concentrations of organochlorine compounds in bald eagles within Voyageurs National Park, Minnesota, USA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>H. Tyler Pittman; William W. Bowerman; Leland H. Grim; Teryl G. Grubb; William C. Bridges; Michael R. Wierda</p> <p>2015-01-01</p> <p>The bald eagle (Haliaeetus leucocephalus) population at Voyageurs National Park (VNP) provides an opportunity to assess long-term temporal and spatial trends of persistent environmental contaminants. Nestling bald eagle plasma samples collected from 1997 to 2010 were analyzed for polychlorinated biphenyls (PCBs) and organochlorine pesticides. Trends of total PCBs,...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/55430','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/55430"><span>Long-term streamflow trends on California’s north coast</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>J. Eli Asarian; Jeffrey D. Walker</p> <p>2017-01-01</p> <p>Using streamflow data from the U.S. Geological Survey, we assessed long-term (1953-2012) trends in streamflow on Californiaâs North Coast including many sites in the redwood region. The study area spans from the Smith River to the Mattole River and includes the Eel and Klamath-Trinity basins. Antecedent Precipitation Index (API) is a time-weighted summary of...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29289770','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29289770"><span>Towards a better understanding of long-term wood-chemistry variations in old-growth forests: A case study on ancient Pinus uncinata trees from the Pyrenees.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hevia, Andrea; Sánchez-Salguero, Raúl; Camarero, J Julio; Buras, Allan; Sangüesa-Barreda, Gabriel; Galván, J Diego; Gutiérrez, Emilia</p> <p>2018-06-01</p> <p>Dendrochemical studies in old forests are still underdeveloped. Old trees growing in remote high-elevation areas far from direct human influence constitute a promising biological proxy for the long-term reconstructions of environmental changes using tree-rings. Furthermore, centennial-long chronologies of multi-elemental chemistry at inter- and intra-annual resolution are scarce. Here, we use a novel non-destructive method by applying Micro X-ray fluorescence (μXRF) to wood samples of old Pinus uncinata trees from two Pyrenean high-elevation forests growing on acidic and basic soils. To disentangle ontogenetic (changes in tree age and diameter) from environmental influences (e.g., climate warming) we compared element patterns in sapwood (SW) and heartwood (HW) during the pre-industrial (1700-1849) and industrial (1850-2008) periods. We quantified tree-ring growth, wood density and relative element concentrations at annual (TRW, tree-ring) to seasonal resolution (EW, earlywood; LW, latewood) and related them to climate variables (temperature and precipitation) and volcanic eruptions in the 18th and 19th centuries. We detected differences for most studied elements between SW and HW along the stem and also between EW and LW within rings. Long-term positive and negative trends were observed for Ca and K, respectively. Cl, P and S showed positive trends during the industrial period. However, differences between sites were also notable. Higher values of Mg, Al, Si and the Ca/Mn ratio were observed at the site with acidic soil. Growing-season temperatures were positively related to growth, maximum wood density and to the concentration of most elements. Peaks in S, Fe, Cl, Zn and Ca were linked to major volcanic eruptions (e.g., Tambora in 1815). Our results reveal the potential of long-term wood-chemistry studies based on the μXRF non-destructive technique to reconstruct environmental changes. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H11I1315R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H11I1315R"><span>Searching for signposts: Adaptive planning thresholds in long-term water supply projections for the Western U.S.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Robinson, B.; Herman, J. D.</p> <p>2017-12-01</p> <p>Long-term water supply planning is challenged by highly uncertain streamflow projections across climate models and emissions scenarios. Recent studies have devised infrastructure and policy responses that can withstand or adapt to an ensemble of scenarios, particularly those outside the envelope of historical variability. An important aspect of this process is whether the proposed thresholds for adaptation (i.e., observations that trigger a response) truly represent a trend toward future change. Here we propose an approach to connect observations of annual mean streamflow with long-term projections by filtering GCM-based streamflow ensembles. Visualizations are developed to investigate whether observed changes in mean annual streamflow can be linked to projected changes in end-of-century mean and variance relative to the full ensemble. A key focus is identifying thresholds that point to significant long-term changes in the distribution of streamflow (+/- 20% or greater) as early as possible. The analysis is performed on 87 sites in the Western United States, using streamflow ensembles through 2100 from a recent study by the U.S. Bureau of Reclamation. Results focus on three primary questions: (1) how many years of observed data are needed to identify the most extreme scenarios, and by what year can they be identified? (2) are these features different between sites? and (3) using this analysis, do observed flows to date at each site point to significant long-term changes? This study addresses the challenge of severe uncertainty in long-term streamflow projections by identifying key thresholds that can be observed to support water supply planning.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5462496','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5462496"><span>Reconstructed storm tracks reveal three centuries of changing moisture delivery to North America</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wise, Erika K.; Dannenberg, Matthew P.</p> <p>2017-01-01</p> <p>Moisture delivery to western North America is closely linked to variability in the westerly storm tracks of midlatitude cyclones, which are, in turn, modified by larger-scale features such as the El Niño–Southern Oscillation system. Instrumental and modeling data suggest that extratropical storm tracks may be intensifying and shifting poleward due to anthropogenic climate change, but it is difficult to separate recent trends from natural variability because of the large amount of decadal and longer variation in storm tracks and their limited instrumental record. We reconstruct cool-season, midlatitude Pacific storm-track position and intensity from 1693 to 1995 CE using existing tree-ring chronologies along with a network of newly developed chronologies from the U.S. Pacific Northwest, where small variations in storm-track position can have a major influence on hydroclimate patterns. Our results show high interannual-to-multidecadal variability in storm-track position and intensity over the past 303 years, with spectral signatures characteristic of tropical and northern Pacific influences. Comparison with reconstructions of precipitation and tropical sea surface temperature confirms the relationship between shifting drought patterns in the Pacific Northwest and storm-track variability through time and demonstrates the long-term influence of El Niño. These results allow us to place recent storm-track changes in the context of decadal and multidecadal fluctuations across the long-term record, showing that recent changes in storm-track intensity likely represent a warming-related increase amplified by natural decadal variability. PMID:28630900</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28630900','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28630900"><span>Reconstructed storm tracks reveal three centuries of changing moisture delivery to North America.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wise, Erika K; Dannenberg, Matthew P</p> <p>2017-06-01</p> <p>Moisture delivery to western North America is closely linked to variability in the westerly storm tracks of midlatitude cyclones, which are, in turn, modified by larger-scale features such as the El Niño-Southern Oscillation system. Instrumental and modeling data suggest that extratropical storm tracks may be intensifying and shifting poleward due to anthropogenic climate change, but it is difficult to separate recent trends from natural variability because of the large amount of decadal and longer variation in storm tracks and their limited instrumental record. We reconstruct cool-season, midlatitude Pacific storm-track position and intensity from 1693 to 1995 CE using existing tree-ring chronologies along with a network of newly developed chronologies from the U.S. Pacific Northwest, where small variations in storm-track position can have a major influence on hydroclimate patterns. Our results show high interannual-to-multidecadal variability in storm-track position and intensity over the past 303 years, with spectral signatures characteristic of tropical and northern Pacific influences. Comparison with reconstructions of precipitation and tropical sea surface temperature confirms the relationship between shifting drought patterns in the Pacific Northwest and storm-track variability through time and demonstrates the long-term influence of El Niño. These results allow us to place recent storm-track changes in the context of decadal and multidecadal fluctuations across the long-term record, showing that recent changes in storm-track intensity likely represent a warming-related increase amplified by natural decadal variability.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GPC...121...19E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GPC...121...19E"><span>Surfing wave climate variability</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Espejo, Antonio; Losada, Iñigo J.; Méndez, Fernando J.</p> <p>2014-10-01</p> <p>International surfing destinations are highly dependent on specific combinations of wind-wave formation, thermal conditions and local bathymetry. Surf quality depends on a vast number of geophysical variables, and analyses of surf quality require the consideration of the seasonal, interannual and long-term variability of surf conditions on a global scale. A multivariable standardized index based on expert judgment is proposed for this purpose. This index makes it possible to analyze surf conditions objectively over a global domain. A summary of global surf resources based on a new index integrating existing wave, wind, tides and sea surface temperature databases is presented. According to general atmospheric circulation and swell propagation patterns, results show that west-facing low to middle-latitude coasts are more suitable for surfing, especially those in the Southern Hemisphere. Month-to-month analysis reveals strong seasonal variations in the occurrence of surfable events, enhancing the frequency of such events in the North Atlantic and the North Pacific. Interannual variability was investigated by comparing occurrence values with global and regional modes of low-frequency climate variability such as El Niño and the North Atlantic Oscillation, revealing their strong influence at both the global and the regional scale. Results of the long-term trends demonstrate an increase in the probability of surfable events on west-facing coasts around the world in recent years. The resulting maps provide useful information for surfers, the surf tourism industry and surf-related coastal planners and stakeholders.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2009/5268/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2009/5268/"><span>Trends in Water Quality in the Southeastern United States, 1973-2005</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Harned, Douglas A.; Staub, Erik L.; Peak, Kelly L.; Tighe, Kirsten M.; Terziotti, Silvia</p> <p>2009-01-01</p> <p>As part of the U.S. Geological Survey National Water-Quality Assessment Program, water-quality data for 334 streams in eight States of the Southeastern United States were assessed for trends from 1973 to 2005. Forty-four U.S. Geological Survey sites were examined for trends in pH, specific conductance, and dissolved oxygen, and in concentrations of dissolved solids, suspended sediment, chloride, sodium, sulfate, silica, potassium, dissolved organic carbon, total nitrogen, total ammonia, total ammonia plus organic nitrogen, dissolved nitrite plus nitrate, and total phosphorus. An additional 290 sites from the U.S. Environmental Protection Agency Storage and Retrieval database were tested for trends in total nitrogen and phosphorus concentrations for the 1975-2004 and 1993-2004 periods. The seasonal Kendall test or Tobit regression was used to detect trends. Concentrations of dissolved constituents have increased in the Southeast during the last 30 years. Specific conductance increased at 62 percent and decreased at 3 percent of the sites, and pH increased at 31 percent and decreased at 11 percent of the sites. Decreasing trends in total nitrogen were detected at 49 percent of the sites, and increasing trends were detected at 10 percent of the sites. Ammonia concentrations decreased at 27 percent of the sites and increased at 6 percent of the sites. Nitrite plus nitrate concentrations increased at 29 percent of the sites and decreased at 10 percent of the sites. These results indicate that the changes in stream nitrogen concentrations generally coincided with improved municipal wastewater-treatment methods. Long-term decreasing trends in total phosphorus were detected at 56 percent of the sites, and increasing trends were detected at 8 percent of the sites. Concentrations of phosphorus have decreased over the last 35 years, which coincided with phosphate-detergent bans and improvements in wastewater treatment that were implemented beginning in 1972. Multiple regression analysis indicated a relation between changes in atmospheric inputs and agricultural practices, and changes in water quality. A long-term water-quality and landscape trends-assessment network for the Southeast is needed to assess changes in water quality over time in response to variations in population, agricultural, wastewater, and landscape variables.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120016294','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120016294"><span>Multi-Decadal Change of Atmospheric Aerosols and Their Effect on Surface Radiation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chin, Mian; Diehl, Thomas; Tan, Qian; Wild, Martin; Qian, Yun; Yu, Hongbin; Bian, Huisheng; Wang, Weiguo</p> <p>2012-01-01</p> <p>We present an investigation on multi-decadal changes of atmospheric aerosols and their effects on surface radiation using a global chemistry transport model along with the near-term to long-term data records. We focus on a 28-year time period of satellite era from 1980 to 2007, during which a suite of aerosol data from satellite observations and ground-based remote sensing and in-situ measurements have become available. We analyze the long-term global and regional aerosol optical depth and concentration trends and their relationship to the changes of emissions" and assess the role aerosols play in the multi-decadal change of solar radiation reaching the surface (known as "dimming" or "brightening") at different regions of the world, including the major anthropogenic source regions (North America, Europe, Asia) that have been experiencing considerable changes of emissions, dust and biomass burning regions that have large interannual variabilities, downwind regions that are directly affected by the changes in the source area, and remote regions that are considered to representing "background" conditions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70189332','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70189332"><span>Climate-induced warming of lakes can be either amplified or suppressed by trends in water clarity</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Rose, Kevin C.; Winslow, Luke A.; Read, Jordan S.; Hansen, Gretchen J. A.</p> <p>2016-01-01</p> <p>Climate change is rapidly warming aquatic ecosystems including lakes and reservoirs. However, variability in lake characteristics can modulate how lakes respond to climate. Water clarity is especially important both because it influences the depth range over which heat is absorbed, and because it is changing in many lakes. Here, we show that simulated long-term water clarity trends influence how both surface and bottom water temperatures of lakes and reservoirs respond to climate change. Clarity changes can either amplify or suppress climate-induced warming, depending on lake depth and the direction of clarity change. Using a process-based model to simulate 1894 north temperate lakes from 1979 to 2012, we show that a scenario of decreasing clarity at a conservative yet widely observed rate of 0.92% yr−1 warmed surface waters and cooled bottom waters at rates comparable in magnitude to climate-induced warming. For lakes deeper than 6.5 m, decreasing clarity was sufficient to fully offset the effects of climate-induced warming on median whole-lake mean temperatures. Conversely, a scenario increasing clarity at the same rate cooled surface waters and warmed bottom waters relative to baseline warming rates. Furthermore, in 43% of lakes, increasing clarity more than doubled baseline bottom temperature warming rates. Long-term empirical observations of water temperature in lakes with and without clarity trends support these simulation results. Together, these results demonstrate that water clarity trends may be as important as rising air temperatures in determining how waterbodies respond to climate change.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012WRR....4812508J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012WRR....4812508J"><span>Role of snow and glacier melt in controlling river hydrology in Liddar watershed (western Himalaya) under current and future climate</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jeelani, G.; Feddema, Johannes J.; van der Veen, Cornelis J.; Stearns, Leigh</p> <p>2012-12-01</p> <p>Snowmelt and icemelt are believed to be important regulators of seasonal discharge of Himalayan rivers. To analyze the long term contribution of snowmelt and glacier/icemelt to river hydrology we apply a water budget model to simulate hydrology of the Liddar watershed in the western Himalaya, India for the 20th century (1901-2010) and future IPCC A1B climate change scenario. Long term (1901-2010) temperature and precipitation data in this region show a warming trend (0.08°C yr-1) and an increase in precipitation (0.28 mm yr-1), with a significant variability in seasonal trends. In particular, winter months have undergone the most warming, along with a decrease in precipitation rates; precipitation has increased throughout the spring. These trends have accelerated the melting and rapid disappearance of snow, causing a seasonal redistribution in the availability of water. Our model results show that about 60% of the annual runoff of the Liddar watershed is contributed from the snowmelt, while only 2% is contributed from glacier ice. The climate trend observed from the 1901 to 2010 time period and its impact on the availability of water will become significantly worse under the IPCC climate change scenarios. Our results suggest that there is a significant shift in the timing and quantity of water runoff in this region of the Himalayas due to snow distribution and melt. With greatly increased spring runoff and its reductions in summer potentially leading to reduced water availability for irrigation agriculture in summer.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23314313','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23314313"><span>Seasonal and annual trends in forage fish mercury concentrations, San Francisco Bay.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Greenfield, Ben K; Melwani, Aroon R; Allen, Rachel M; Slotton, Darell G; Ayers, Shaun M; Harrold, Katherine H; Ridolfi, Katherine; Jahn, Andrew; Grenier, J Letitia; Sandheinrich, Mark B</p> <p>2013-02-01</p> <p>San Francisco Bay is contaminated by mercury (Hg) due to historic and ongoing sources, and has elevated Hg concentrations throughout the aquatic food web. We monitored Hg in forage fish to indicate seasonal and interannual variations and trends. Interannual variation and long-term trends were determined by monitoring Hg bioaccumulation during September-November, for topsmelt (Atherinops affinis) and Mississippi silverside (Menidia audens) at six sites, over six years (2005 to 2010). Seasonal variation was characterized for arrow goby (Clevelandia ios) at one site, topsmelt at six sites, and Mississippi silverside at nine sites. Arrow goby exhibited a consistent seasonal pattern from 2008 to 2010, with lowest concentrations observed in late spring, and highest concentrations in late summer or early fall. In contrast, topsmelt concentrations tended to peak in late winter or early spring and silverside seasonal fluctuations varied among sites. The seasonal patterns may relate to seasonal shifts in net MeHg production in the contrasting habitats of the species. Topsmelt exhibited an increase in Alviso Slough from 2005 to 2010, possibly related to recent hypoxia in that site. Otherwise, directional trends for Hg in forage fish were not observed. For topsmelt and silverside, the variability explained by year was relatively low compared to sampling station, suggesting that interannual variation is not a strong influence on Hg concentrations. Although fish Hg has shown long-term declines in some ecosystems around the world, San Francisco Bay forage fish did not decline over the six-year monitoring period examined. Copyright © 2012 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27956624','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27956624"><span>No growth stimulation of Canada's boreal forest under half-century of combined warming and CO2 fertilization.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Girardin, Martin P; Bouriaud, Olivier; Hogg, Edward H; Kurz, Werner; Zimmermann, Niklaus E; Metsaranta, Juha M; de Jong, Rogier; Frank, David C; Esper, Jan; Büntgen, Ulf; Guo, Xiao Jing; Bhatti, Jagtar</p> <p>2016-12-27</p> <p>Considerable evidence exists that current global temperatures are higher than at any time during the past millennium. However, the long-term impacts of rising temperatures and associated shifts in the hydrological cycle on the productivity of ecosystems remain poorly understood for mid to high northern latitudes. Here, we quantify species-specific spatiotemporal variability in terrestrial aboveground biomass stem growth across Canada's boreal forests from 1950 to the present. We use 873 newly developed tree-ring chronologies from Canada's National Forest Inventory, representing an unprecedented degree of sampling standardization for a large-scale dendrochronological study. We find significant regional- and species-related trends in growth, but the positive and negative trends compensate each other to yield no strong overall trend in forest growth when averaged across the Canadian boreal forest. The spatial patterns of growth trends identified in our analysis were to some extent coherent with trends estimated by remote sensing, but there are wide areas where remote-sensing information did not match the forest growth trends. Quantifications of tree growth variability as a function of climate factors and atmospheric CO 2 concentration reveal strong negative temperature and positive moisture controls on spatial patterns of tree growth rates, emphasizing the ecological sensitivity to regime shifts in the hydrological cycle. An enhanced dependence of forest growth on soil moisture during the late-20th century coincides with a rapid rise in summer temperatures and occurs despite potential compensating effects from increased atmospheric CO 2 concentration.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/50870','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/50870"><span>The long term agroecosystem research network - shared research strategy</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Jean L. Steiner; Timothy Strickland; Peter J.A. Kleinman; Kris Havstad; Thomas B. Moorman; M.Susan Moran; Phil Hellman; Ray B. Bryant; David Huggins; Greg McCarty</p> <p>2016-01-01</p> <p>While current weather patterns and rapidly accelerated changes in technology often focus attention on short-term trends in agriculture, the fundamental demands on modern agriculture to meet society food, feed, fuel and fiber production while providing the foundation for a healthy environment requires long-term perspective. The Long- Term Agroecoystem Research Network...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ECSS..182...40P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ECSS..182...40P"><span>Mediterranean dunes on the go: Evidence from a short term study on coastal herbaceous vegetation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prisco, Irene; Stanisci, Angela; Acosta, Alicia T. R.</p> <p>2016-12-01</p> <p>Detailed monitoring studies on permanent sites are a promising tool for an accurate evaluation of short, medium or long term vegetation dynamics. This work aims to evaluate short-term changes in coastal dune herbaceous plant species and EU Habitats through a multi-temporal analysis using permanent vegetation transects. In particular, (I) we analyze changes in species richness of coastal habitats; (II) we identify changes in plant cover of selected focal plants; and (III) we relate the changes to selected climatic variables and erosion/accretion processes. We selected one of the Italian's peninsula best preserved coastal dune areas (ca. 50 km along the Adriatic sea) with a relatively homogeneous coastal zonation and low anthropic pressure but with different erosion/accretion processes. We explored changes in richness over time using generalized linear models (GLMs). We identified different ecological guilds: focal, ruderal and alien plant species and investigated temporal trends in these guilds' species richness. We also applied GLMs to determine how plant cover of the most important focal species have changed over time. Overall, in this study we observed that the influence of climatic variables was relatively small. However, we found remarkable different trends in response to erosion/accretion processes both at community and at species level. Thus, our results highlight the importance of coastal dynamics in preserving not only coastal vegetation zonation, but also species richness and focal species cover. Moreover, we identified the dune grasslands as the most sensitive habitat for detecting the influence of climatic variables throughout a short term monitoring survey. Information from this study provides useful insights for detecting changes in vegetation, for establishing habitat protection priorities and for improving conservation efforts for these fragile ecosystems.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PhyA..388.4727D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PhyA..388.4727D"><span>Long-term oscillations in the sleep/wake cycle of infants</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Diambra, L.; Malta, C. P.; Capurro, A.</p> <p>2009-11-01</p> <p>The development of circadian sleep-wakefulness rhythm was investigated by a longitudinal study of six normal infants. We propose an entropy based measure for the sleep/wake cycle fragmentation. Our results confirm that the sleep/wake cycle fragmentation and the sleep/wake ratio decrease, while the circadian power increases during the maturation process of infants. In addition to these expected linear trends in the variables devised to quantify sleep consolidation, circadian power and sleep/wake ratio, we found that they present infradian rhythms in the monthly range.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70186197','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70186197"><span>Correction of stream quality trends for the effects of laboratory measurement bias</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Alexander, Richard B.; Smith, Richard A.; Schwarz, Gregory E.</p> <p>1993-01-01</p> <p>We present a statistical model relating measurements of water quality to associated errors in laboratory methods. Estimation of the model allows us to correct trends in water quality for long-term and short-term variations in laboratory measurement errors. An illustration of the bias correction method for a large national set of stream water quality and quality assurance data shows that reductions in the bias of estimates of water quality trend slopes are achieved at the expense of increases in the variance of these estimates. Slight improvements occur in the precision of estimates of trend in bias by using correlative information on bias and water quality to estimate random variations in measurement bias. The results of this investigation stress the need for reliable, long-term quality assurance data and efficient statistical methods to assess the effects of measurement errors on the detection of water quality trends.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.A43B0130W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.A43B0130W"><span>Thirty Years of Cloud Cover Patterns from Satellite Data: Fog in California's Central Valley and Coast</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Waller, E.; Baldocchi, D. D.</p> <p>2012-12-01</p> <p>In an effort to assess long term trends in winter fog in the Central Valley of California, custom maps of daily cloud cover from an approximately 30 year record of AVHRR (1981-1999) and MODIS (2000-2012) satellite data were generated. Spatial rules were then used to differentiate between fog and general cloud cover. Differences among the sensors (e.g., spectral content, spatial resolution, overpass time) presented problems of consistency, but concurrent climate station data were used to resolve systematic differences in products, and to confirm long term trends. The frequency and extent of Central Valley ("Tule") fog appear to have some periodic oscillation, but also appear to be on the decline, especially in the Sacramento Valley and in the "shoulder" months of November and February. These results may have strong implications for growers of fruit and nut trees in the Central Valley dependent on winter chill hours that are augmented by the foggy daytime conditions. Conclusions about long term trends in fog are limited to daytime patterns, as results are primarily derived from reflectance-based products. Similar analyses of daytime cloud cover are performed on other areas of concern, such as the coastal fog belt of California. Large area and long term patterns here appear to have periodic oscillation similar to that for the Central Valley. However, the relatively coarse spatial resolution of the AVHRR LTDR (Long Term Data Record) data (~5-km) may be limiting for fine-scale analysis of trends.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5978074','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5978074"><span>Investigation of the Behavior of Hardening Masonry Exposed to Variable Stresses</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Šlivinskas, Tomas; Jonaitis, Bronius; Marčiukaitis, Jonas Gediminas</p> <p>2018-01-01</p> <p>This paper analyzes the behavior of masonry under variable loads during execution (construction stage). It specifies the creep coefficient for calcium silicate brick masonry, presenting the research data of masonry deformation under variable and constant long-term loads. The interaction of separate layers of composite material in masonry is introduced and the formulae for determining long-term deformations are offered. The research results of masonry’s compressive strength and deformation properties under variable and constant long-term loads are presented. These are then compared to calculated ones. According to the presented comparison, the calculated long-term deformations coincide quite well with those determined experimentally. PMID:29710802</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29710802','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29710802"><span>Investigation of the Behavior of Hardening Masonry Exposed to Variable Stresses.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Šlivinskas, Tomas; Jonaitis, Bronius; Marčiukaitis, Jonas Gediminas; Zavalis, Robertas</p> <p>2018-04-28</p> <p>This paper analyzes the behavior of masonry under variable loads during execution (construction stage). It specifies the creep coefficient for calcium silicate brick masonry, presenting the research data of masonry deformation under variable and constant long-term loads. The interaction of separate layers of composite material in masonry is introduced and the formulae for determining long-term deformations are offered. The research results of masonry’s compressive strength and deformation properties under variable and constant long-term loads are presented. These are then compared to calculated ones. According to the presented comparison, the calculated long-term deformations coincide quite well with those determined experimentally.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.jstor.org/stable/3809660','USGSPUBS'); return false;" href="http://www.jstor.org/stable/3809660"><span>Recent trends in counts of migrant hawks from northeastern North America</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Titus, K.; Fuller, M.R.</p> <p>1990-01-01</p> <p>Using simple regression, pooled-sites route-regression, and nonparametric rank-trend analyses, we evaluated trends in counts of hawks migrating past 6 eastern hawk lookouts from 1972 to 1987. The indexing variable was the total count for a season. Bald eagle (Haliaeetus leucocephalus), peregrine falcon (Falco peregrinus), merlin (F. columbarius), osprey (Pandion haliaetus), and Cooper's hawk (Accipiter cooperii) counts increased using route-regression and nonparametric methods (P 0.10). We found no consistent trends (P > 0.10) in counts of sharp-shinned hawks (A. striatus), northern goshawks (A. gentilis) red-shouldered hawks (Buteo lineatus), red-tailed hawks (B. jamaicensis), rough-legged hawsk (B. lagopus), and American kestrels (F. sparverius). Broad-winged hawk (B. platypterus) counts declined (P < 0.05) based on the route-regression method. Empirical comparisons of our results with those for well-studied species such as the peregrine falcon, bald eagle, and osprey indicated agreement with nesting surveys. We suggest that counts of migrant hawks are a useful and economical method for detecting long-term trends in species across regions, particularly for species that otherwise cannot be easily surveyed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70147398','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70147398"><span>Icefield-to-ocean linkages across the northern Pacific coastal temperate rainforest ecosystem</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>O'Neel, Shad; Hood, Eran; Bidlack, Allison L.; Fleming, Sean W.; Arimitsu, Mayumi L.; Arendt, Anthony; Burgess, Evan W.; Sergeant, Christopher J.; Beaudreau, Anne E.; Timm, Kristin; Hayward, Gregory D.; Reynolds, Joel H.; Pyare, Sanjay</p> <p>2015-01-01</p> <p>Rates of glacier mass loss in the northern Pacific coastal temperate rainforest (PCTR) are among the highest on Earth, and changes in glacier volume and extent will affect the flow regime and chemistry of coastal rivers, as well as the nearshore marine ecosystem of the Gulf of Alaska. Here we synthesize physical, chemical and biological linkages that characterize the northern PCTR ecosystem, with particular emphasis on the potential impacts of glacier change in the coastal mountain ranges on the surface–water hydrology, biogeochemistry, coastal oceanography and aquatic ecology. We also evaluate the relative importance and interplay between interannual variability and long-term trends in key physical drivers and ecological responses. To advance our knowledge of the northern PCTR, we advocate for cross-disciplinary research bridging the icefield-to-ocean ecosystem that can be paired with long-term scientific records and designed to inform decisionmakers.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040171821&hterms=chronicle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dchronicle','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040171821&hterms=chronicle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dchronicle"><span>Brightness Variations in the Central Star of Eta Carinae From 1998 to the Present</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Martin, J. C.; Koppelman, M. D.</p> <p>2004-01-01</p> <p>Recently, Eta Carinae has varied suprisingly in brightness combining a long term brightening trend with a 5.5-year cycle and unpredictable sporadic jumps. Only the Hubble Space Telescope had been able to provide reliable photometry of the central star resolved separately from its bright ejecta. We present data from the Hubble Space Telescope Space Telescope Imaging Spectrograph (STIS) and the Advanced Camera for Surveys High Resolution Camera (ACS/HRC) which chronicle the dramatic brightening of the central star of Eta Carinae from the 1998 "event" through 2000 and show that is has continued to slowly brighten. More frequent photometry during its recent "event" and a continued rise afterward. These data are compared to the more long term data compiled by the American Association of Variable Star Observers (AAVSO) which also shows substantial brightening between events and other intervening fluctuations in the brightness of Eta Carinae at visual wavelengths.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170000986&hterms=Change+climate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DChange%2Bclimate','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170000986&hterms=Change+climate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DChange%2Bclimate"><span>Cross - Scale Intercomparison of Climate Change Impacts Simulated by Regional and Global Hydrological Models in Eleven Large River Basins</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hattermann, F. F.; Krysanova, V.; Gosling, S. N.; Dankers, R.; Daggupati, P.; Donnelly, C.; Florke, M.; Huang, S.; Motovilov, Y.; Buda, S.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20170000986'); toggleEditAbsImage('author_20170000986_show'); toggleEditAbsImage('author_20170000986_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20170000986_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20170000986_hide"></p> <p>2017-01-01</p> <p>Ideally, the results from models operating at different scales should agree in trend direction and magnitude of impacts under climate change. However, this implies that the sensitivity to climate variability and climate change is comparable for impact models designed for either scale. In this study, we compare hydrological changes simulated by 9 global and 9 regional hydrological models (HM) for 11 large river basins in all continents under reference and scenario conditions. The foci are on model validation runs, sensitivity of annual discharge to climate variability in the reference period, and sensitivity of the long-term average monthly seasonal dynamics to climate change. One major result is that the global models, mostly not calibrated against observations, often show a considerable bias in mean monthly discharge, whereas regional models show a better reproduction of reference conditions. However, the sensitivity of the two HM ensembles to climate variability is in general similar. The simulated climate change impacts in terms of long-term average monthly dynamics evaluated for HM ensemble medians and spreads show that the medians are to a certain extent comparable in some cases, but have distinct differences in other cases, and the spreads related to global models are mostly notably larger. Summarizing, this implies that global HMs are useful tools when looking at large-scale impacts of climate change and variability. Whenever impacts for a specific river basin or region are of interest, e.g. for complex water management applications, the regional-scale models calibrated and validated against observed discharge should be used.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/1347844-cross-scale-intercomparison-climate-change-impacts-simulated-regional-global-hydrological-models-eleven-large-river-basins','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1347844-cross-scale-intercomparison-climate-change-impacts-simulated-regional-global-hydrological-models-eleven-large-river-basins"><span>Cross-scale intercomparison of climate change impacts simulated by regional and global hydrological models in eleven large river basins</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Hattermann, F. F.; Krysanova, V.; Gosling, S. N.</p> <p></p> <p>Ideally, the results from models operating at different scales should agree in trend direction and magnitude of impacts under climate change. However, this implies that the sensitivity of impact models designed for either scale to climate variability and change is comparable. In this study, we compare hydrological changes simulated by 9 global and 9 regional hydrological models (HM) for 11 large river basins in all continents under reference and scenario conditions. The foci are on model validation runs, sensitivity of annual discharge to climate variability in the reference period, and sensitivity of the long-term average monthly seasonal dynamics to climatemore » change. One major result is that the global models, mostly not calibrated against observations, often show a considerable bias in mean monthly discharge, whereas regional models show a much better reproduction of reference conditions. However, the sensitivity of two HM ensembles to climate variability is in general similar. The simulated climate change impacts in terms of long-term average monthly dynamics evaluated for HM ensemble medians and spreads show that the medians are to a certain extent comparable in some cases with distinct differences in others, and the spreads related to global models are mostly notably larger. Summarizing, this implies that global HMs are useful tools when looking at large-scale impacts of climate change and variability, but whenever impacts for a specific river basin or region are of interest, e.g. for complex water management applications, the regional-scale models validated against observed discharge should be used.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1814709F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1814709F"><span>Soil microclimate monitoring in forested and meadow sites</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Freyerova, Katerina; Safanda, Jan</p> <p>2016-04-01</p> <p>It is well known fact that forest microclimate differs from open area microclimate (Geiger 1965). Less attention is paid to soil temperatures and their long-term monitoring. To evaluate and compare these two environments from the soil microclimate point of view, Institute of Geophysics in Prague monitors soil and air temperatures in Bedřichov in the Jizerské Hory Mountains (Czech Republic). The soil temperatures are measured in three depths (20, 50 and 100 cm) in forest (700 m a. s. l.) and meadow (750 m a. s. l.). Air temperatures are measured at 2m height both in forest and meadow. Nowadays, we have more than three years long time series. The most of studies and experiments described in literature are short-term ones (in order of days or weeks). However, from short-term experiments the seasonal behaviour and trends can be hardly identified and conclusions on soil temperature reaction to climatic extremes such as heat waves, drought or freeze cannot be done with confidence. These drawbacks of the short-term experiments are discussed in literature (eg. Morecroft et al. 1998; Renaud et al. 2011). At the same, with progression of the global warming, the expected increasing frequency of climatic extremes will affect the future form of forest vegetation (Von Arx et al. 2012). The soil and air temperature series, both from the forest and meadow sites, are evaluated and interpreted with respect to long term temperature characteristics and seasonal trends. The emphasis is given on the soil temperature responses to extreme climatic situations. We examine variability between the localities and depths and spatial and temporal changes in this variability. This long-term monitoring allows us to better understand and examine the behaviour of the soil temperature in extreme weather situations. Therefore, we hope to contribute to better prediction of future reactions of this specific environments to the climate change. Literature Geiger, R., 1965. The climate near the ground, Harvard University Press. Available at: https://books.google.cz/books?id=fTpRAAAAMAAJ. Morecroft, M.D., Taylor, M.E. & Oliver, H.R., 1998. Air and soil microclimates of deciduous woodland compared to an open site. Agricultural and Forest Meteorology, 90(1-2), pp.141-156. Renaud, V. et al., 2011. Comparison between open-site and below-canopy climatic conditions in Switzerland for different types of forests over 10 years (1998-2007). Theoretical and Applied Climatology, 105(1-2), pp.119-127. Available at: http://link.springer.com/10.1007/s00704-010-0361-0. Von Arx, G., Dobbertin, M. & Rebetez, M., 2012. Spatio-temporal effects of forest canopy on understory microclimate in a long-term experiment in Switzerland. Agricultural and Forest Meteorology, 166-167, pp.144-155. Available at: http://dx.doi.org/10.1016/j.agrformet.2012.07.018.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23600253','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23600253"><span>Variability in winter climate and winter extremes reduces population growth of an alpine butterfly.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Roland, Jens; Matter, Stephen F</p> <p>2013-01-01</p> <p>We examined the long-term, 15-year pattern of population change in a network of 21 Rocky Mountain populations of Parnassius smintheus butterflies in response to climatic variation. We found that winter values of the broadscale climate variable, the Pacific Decadal Oscillation (PDO) index, were a strong predictor of annual population growth, much more so than were endogenous biotic factors related to population density. The relationship between PDO and population growth was nonlinear. Populations declined in years with extreme winter PDO values, when there were either extremely warm or extremely cold sea surface temperatures in the eastern Pacific relative to that in the western Pacific. Results suggest that more variable winters, and more frequent extremely cold or warm winters, will result in more frequent decline of these populations, a pattern exacerbated by the trend for increasingly variable winters seen over the past century.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMPP43D..03H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMPP43D..03H"><span>An ensemble approach to reconstructing 20th century climate trends in data-sparse regions of the tropical Pacific using young fossil corals</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hitt, N. T.; Cobb, K. M.; Sayani, H. R.; Grothe, P. R.; Atwood, A. R.; O'Connor, G.; Chen, T.; Hagos, M. M.; Deocampo, D.; Edwards, R. L.; Cheng, H.; Lu, Y.; Thompson, D. M.</p> <p>2016-12-01</p> <p>Sea-surface temperature (SST) variability in the central tropical Pacific drives global-scale responses through atmospheric teleconnections, so the response of this region to anthropogenic forcing has important implications for regional climate responses in many areas. However, quantification of anthropogenic SST trends in the central tropical Pacific is complicated by the fact that instrumental SST observations in this region are extremely limited prior to 1950, with trends of opposite sign observed across the various gridded instrumental datasets (Deser et al., 2010). Researchers have turned to multi-century coral records to reconstruct ocean temperatures through time, but the paucity of such records prohibits the generation of uncertainty estimates. In this study, we use a large collection of U/Th-dated fossil corals that to investigate a new ensemble approach to reconstructing temperature from the Central Pacific over the late 20th century. Here we combine monthly-resolved d18O and Sr/Ca from 8 5-14 year long coral records from Christmas Island (2°N, 157°W) to quantify temperature and hydrological trends in this region from 1930 to present. We compare our fossil coral ensemble reconstruction to a long modern coral core from this site that extends back to 1940, as well as to gridded SST datasets. We also provide the first well-replicated coral d18O and Sr/Ca records across both the 1997/98 and 2015/2016 El Nino events, comparing the strength of these two events in the context of long-term temperature trends observed in our longer reconstruction. We conclude that the fossil coral ensemble approach provides a robust means of reconstructing 20th century climate trends. Deser et al., 2010, GRL, doi: 10.1029/2010GL043321</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19628457','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19628457"><span>Processing short-term and long-term information with a combination of polynomial approximation techniques and time-delay neural networks.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fuchs, Erich; Gruber, Christian; Reitmaier, Tobias; Sick, Bernhard</p> <p>2009-09-01</p> <p>Neural networks are often used to process temporal information, i.e., any kind of information related to time series. In many cases, time series contain short-term and long-term trends or behavior. This paper presents a new approach to capture temporal information with various reference periods simultaneously. A least squares approximation of the time series with orthogonal polynomials will be used to describe short-term trends contained in a signal (average, increase, curvature, etc.). Long-term behavior will be modeled with the tapped delay lines of a time-delay neural network (TDNN). This network takes the coefficients of the orthogonal expansion of the approximating polynomial as inputs such considering short-term and long-term information efficiently. The advantages of the method will be demonstrated by means of artificial data and two real-world application examples, the prediction of the user number in a computer network and online tool wear classification in turning.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JSR...135...11S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JSR...135...11S"><span>Does ecosystem variability explain phytoplankton diversity? Solving an ecological puzzle with long-term data sets</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sarker, Subrata; Lemke, Peter; Wiltshire, Karen H.</p> <p>2018-05-01</p> <p>Explaining species diversity as a function of ecosystem variability is a long-term discussion in community-ecology research. Here, we aimed to establish a causal relationship between ecosystem variability and phytoplankton diversity in a shallow-sea ecosystem. We used long-term data on biotic and abiotic factors from Helgoland Roads, along with climate data to assess the effect of ecosystem variability on phytoplankton diversity. A point cumulative semi-variogram method was used to estimate the long-term ecosystem variability. A Markov chain model was used to estimate dynamical processes of species i.e. occurrence, absence and outcompete probability. We identified that the 1980s was a period of high ecosystem variability while the last two decades were comparatively less variable. Ecosystem variability was found as an important predictor of phytoplankton diversity at Helgoland Roads. High diversity was related to low ecosystem variability due to non-significant relationship between probability of a species occurrence and absence, significant negative relationship between probability of a species occurrence and probability of a species to be outcompeted by others, and high species occurrence at low ecosystem variability. Using an exceptional marine long-term data set, this study established a causal relationship between ecosystem variability and phytoplankton diversity.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.A53Q0444P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.A53Q0444P"><span>Interpretation of tropospheric ozone variability in data with different vertical and temporal resolution</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Petropavlovskikh, I. V.; Disterhoft, P.; Johnson, B. J.; Rieder, H. E.; Manney, G. L.; Daffer, W.</p> <p>2012-12-01</p> <p>This work attributes tropospheric ozone variability derived from the ground-based Dobson and Brewer Umkehr measurements and from ozone sonde data to local sources and transport. It assesses capability and limitations in both types of measurements that are often used to analyze long- and short-term variability in tropospheric ozone time series. We will address the natural and instrument-related contribution to the variability found in both Umkehr and sonde data. Validation of Umkehr methods is often done by intercomparisons against independent ozone measuring techniques such as ozone sounding. We will use ozone-sounding in its original and AK-smoothed vertical profiles for assessment of ozone inter-annual variability over Boulder, CO. We will discuss possible reasons for differences between different ozone measuring techniques and its effects on the derived ozone trends. Next to standard evaluation techniques we utilize a STL-decomposition method to address temporal variability and trends in the Boulder Umkehr data. Further, we apply a statistical modeling approach to the ozone data set to attribute ozone variability to individual driving forces associated with natural and anthropogenic causes. To this aim we follow earlier work applying a backward selection method (i.e., a stepwise elimination procedure out of a set of total 44 explanatory variables) to determine those explanatory variables which contribute most significantly to the observed variability. We will present also some results associated with completeness (sampling rate) of the existing data sets. We will also use MERRA (Modern-Era Retrospective analysis for Research and Applications) re-analysis results selected for Boulder location as a transfer function in understanding of the effects that the temporal sampling and vertical resolution bring into trend and ozone variability analysis. Analyzing intra-annual variability in ozone measurements over Boulder, CO, in relation to the upper tropospheric subtropical and polar jets, we will address the stratospheric and tropospheric intrusions in the middle latitude troposphere ozone field.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC31B0997M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC31B0997M"><span>Large-scale estimates of gross primary production on the Qinghai-Tibet plateau based on remote sensing data</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ma, M., II; Yuan, W.; Dong, J.; Zhang, F.; Cai, W.; Li, H.</p> <p>2017-12-01</p> <p>Vegetation gross primary production (GPP) is an important variable for the carbon cycle on the Qinghai-Tibetan Plateau (QTP). Based on the measurements from twelve eddy covariance (EC) sites, we validated a light use efficiency model (i.e. EC-LUE) to evaluate the spatial-temporal patterns of GPP and the effect of environmental variables on QTP. The EC-LUE model explained 85.4% of the daily observed GPP variations through all of the twelve EC sites, and characterized very well the seasonal changes of GPP. Annual GPP over the entire QTP ranged from 575 to 703 Tg C, and showed a significantly increasing trend from 1982 to 2013. However, there were large spatial heterogeneities in long-term trends of GPP. Throughout the entire QTP, air temperature TA increase had a greater influence than solar radiation and PREC changes on productivity. Moreover, our results highlight the large uncertainties of previous GPP estimates due to insufficient parameterization and validations. When compared with GPP estimates of the EC-LUE model, most Coupled Model Intercomparison Project (CMIP5) GPP products overestimate the magnitude and increasing trends of regional GPP, which potentially impact the feedback of ecosystems to regional climate changes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JARS...12a6022P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JARS...12a6022P"><span>Analysis of spatiotemporal variability of C-factor derived from remote sensing data</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pechanec, Vilém; Mráz, Alexander; Benc, Antonín; Cudlín, Pavel</p> <p>2018-01-01</p> <p>Soil erosion is an important phenomenon that contributes to the degradation of agricultural land. Even though it is a natural process, human activities can significantly increase its impact on land degradation and present serious limitation on sustainable agricultural land use. Nowadays, the risk of soil erosion is assessed either qualitatively by expert assessment or quantitatively using model-based approach. One of the primary factors affecting the soil erosion assessment is a cover-management factor, C-factor. In the Czech Republic, several models are used to assess the C-factor on a long-term basis based on data collected using traditional tabular methods. This paper presents work to investigate the estimation of both long-term and short-term cover-management factors using remote sensing data. The results demonstrate a successful development of C-factor maps for each month of 2014, growing season average, and annual average for the Czech Republic. C-factor values calculated from remote sensing data confirmed expected trend in their temporal variability for selected crops. The results presented in this paper can be used for enhancing existing methods for estimating C-factor, planning future agricultural activities, and designing technical remediations and improvement activities of land use in the Czech Republic, which are also financially supported by the European Union funds.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950004222','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950004222"><span>Trend analysis of the long-term Swiss ozone measurements</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Staehelin, Johannes; Bader, Juerg; Gelpke, Verena</p> <p>1994-01-01</p> <p>Trend analyses, assuming a linear trend which started at 1970, were performed from total ozone measurements from Arosa (Switzerland, 1926-1991). Decreases in monthly mean values were statistically significant for October through April showing decreases of about 2.0-4 percent per decade. For the period 1947-91, total ozone trends were further investigated using a multiple regression model. Temperature of a mountain peak in Switzerland (Mt. Santis), the F10.7 solar flux series, the QBO series (quasi biennial oscillation), and the southern oscillation index (SOI) were included as explanatory variables. Trends in the monthly mean values were statistically significant for December through April. The same multiple regression model was applied to investigate the ozone trends at various altitudes using the ozone balloon soundings from Payerne (1967-1989) and the Umkehr measurements from Arosa (1947-1989). The results show four different vertical trend regimes: On a relative scale changes were largest in the troposphere (increase of about 10 percent per decade). On an absolute scale the largest trends were obtained in the lower stratosphere (decrease of approximately 6 per decade at an altitude of about 18 to 22 km). No significant trends were observed at approximately 30 km, whereas stratospheric ozone decreased in the upper stratosphere.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MsT.........25B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MsT.........25B"><span>Landscape variability of vegetation change across the forest to tundra transition of central Canada</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bonney, Mitchell Thurston</p> <p></p> <p>Widespread vegetation productivity increases in tundra ecosystems and stagnation, or even productivity decreases, in boreal forest ecosystems have been detected from coarse-scale remote sensing observations over the last few decades. However, finer-scale Landsat studies have shown that these changes are heterogeneous and may be related to landscape and regional variability in climate, land cover, topography and moisture. In this study, a Landsat Normalized Difference Vegetation Index (NDVI) time-series (1984-2016) was examined for a study area spanning the entirety of the sub-Arctic boreal forest to Low Arctic tundra transition of central Canada (i.e., Yellowknife to the Arctic Ocean). NDVI trend analysis indicated that 27% of un-masked pixels in the study area exhibited a significant (p < 0.05) trend and virtually all (99.3%) of those pixels were greening. Greening pixels were most common in the northern tundra zone and the southern forest-tundra ecotone zone. NDVI trends were positive throughout the study area, but were smallest in the forest zone and largest in the northern tundra zone. These results were supported by ground validation, which found a strong relationship (R2 = 0.81) between bulk vegetation volume (BVV) and NDVI for non-tree functional groups in the North Slave region of Northwest Territories. Field observations indicate that alder (Alnus spp.) shrublands and open woodland sites with shrubby understories were most likely to exhibit greening in that area. Random Forest (RF) modelling of the relationship between NDVI trends and environmental variables found that the magnitude and direction of trends differed across the forest to tundra transition. Increased summer temperatures, shrubland and forest land cover, closer proximity to major drainage systems, longer distances from major lakes and lower elevations were generally more important and associated with larger positive NDVI trends. These findings indicate that the largest positive NDVI trends were primarily associated with the increased productivity of shrubby environments, especially at, and north of the forest-tundra ecotone in areas with more favorable growing conditions. Smaller and less significant NDVI trends in boreal forest environments south of the forest-tundra ecotone were likely associated with long-term recovery from fire disturbance rather than the variables analyzed here.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JOUC...16..717Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JOUC...16..717Z"><span>Trends in significant wave height and surface wind speed in the China Seas between 1988 and 2011</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zheng, Chongwei; Zhang, Ren; Shi, Weilai; Li, Xin; Chen, Xuan</p> <p>2017-10-01</p> <p>Wind and waves are key components of the climate system as they drive air-sea interactions and influence weather systems and atmospheric circulation. In marine environments, understanding surface wind and wave fields and their evolution over time is important for conducting safe and efficient human activities, such as navigation and engineering. This study considers long-term trends in the sea surface wind speed (WS) and significant wave height (SWH) in the China Seas over the period 1988-2011 using the Cross-Calibrated Multi-Platform (CCMP) ocean surface wind product and a 24-year hindcast wave dataset obtained from the WAVEWATCH-III (WW3) wave model forced with CCMP winds. The long-term trends in WS and SWH in the China Seas are analyzed over the past 24 years to provide a reference point from which to assess future climate change and offshore wind and wave energy resource development in the region. Results demonstrate that over the period 1988-2011 in the China Seas: 1) WS and SWH showed a significant increasing trend of 3.38 cm s-1 yr-1 and 1.52 cm yr-1, respectively; 2) there were notable regional differences in the long-term trends of WS and SWH; 3) areas with strong increasing trends were located mainly in the middle of the Tsushima Strait, the northern and southern areas of the Taiwan Strait, and in nearshore regions of the northern South China Sea; and 4) the long-term trend in WS was closely associated with El Niño and a significant increase in the occurrence of gale force winds in the region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110022998','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110022998"><span>Subtropical Gyre Variability as Seen from Satellites</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Signorini, Sergio R.; McClain, Charles R.</p> <p>2011-01-01</p> <p>A satellite multi-sensor approach is used to analyse the biological response of open ocean regions of the subtropical gyres to changes in physical forcing. Thirteen years (1998-2010) of SeaWiFS chlorophyll a (Chl-a), combined with concurrent satellite records of sea-surface temperature (SST) and sea level height, were analysed to investigate the seasonal and interannual variability of Chl-a concentration within these immense so-called ocean deserts. The seasonal variability of Chl-a within the gyres is driven mostly by the warming/cooling of surface waters. Summer warming promotes shallower mixed layers and lower Chl-a due to a reduction of vertical mixing and consequently a decrease in nutrient supply. The opposite happens during the winter cooling period. Therefore, long-term trends in SST have the potential to cause an impact on the interannual variability of Chl-a. Our analyses show that, during the 13 whole years of SeaWiFS data record, the North Pacific, Indian Ocean, and North Atlantic gyres experienced a decrease in Chl-a of 9%, 12%, and 11%, respectively, with corresponding SST increases of 0.27 C, 0.42 C, and 0.32 C. The South Pacific and South Atlantic gyres also showed warming trends but with weak positive trends in Chl-a that are not statistically significant. We hypothesize that the warming of surface waters in these two gyres are counterbalanced by other interacting physical and biological driving mechanisms, as indicated in previous studies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.3512L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.3512L"><span>Is solar correction for long-term trend studies stable?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Laštovička, Jan</p> <p>2017-04-01</p> <p>When calculating long-term trends in the ionosphere, the effect of the 11-year solar cycle (i.e. of solar activity) must be removed from data, because it is much stronger than the long-term trend. When a data series is analyzed for trend, usual approach is first to calculate from all data their dependence on solar activity and create an observational model of dependence on solar activity. Then the model data are subtracted from observations and trend is computed from residuals. This means that it is assumed that the solar activity dependence is stable over the whole data series period of time. But what happens if it is not the case? As an ionospheric parameter we consider foE from two European stations with the best long data series of parameters of the ionospheric E layer, Slough/Chilton and Juliusruh over 1975-2014 (40 years). Noon-time medians (10-14 LT) are analyzed. The trend pattern after removing solar influence with one correction for the whole period is complex. For yearly average values for both stations first foE is slightly decreasing in 1975-1990, then the trend levels off or a very little increase occurs in 1990-2005, and finally in 2006-2014 a remarkable decrease is observed. This does not seem to be physically plausible. However, when the solar correction is calculated separately for the three above periods, we obtain a smooth slightly negative trend which changes after the mid-1990 into no trend in coincidence with change of ozone trend. While solar corrections for the first two periods are similar (even though not equal), the solar activity dependence of foE in the third period (lower solar activity) is clearly different. Also foF2 trend revealed some effect of unstable solar correction. Thus the stability of solar correction should be carefully tested when calculating ionospheric trends. This could perhaps explain some of differences between the past published trend results.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20060012293','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20060012293"><span>Secular changes of the M2 tide in the Gulf of Maine</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ray, Richard D.</p> <p>2005-01-01</p> <p>Analyses of long time series of hourly tide-gauge data at four stations in the Gulf of Maine reveal that the amplitude of the M2 tide underwent a nearly linear secular increase throughout most of the twentieth century. In the early 1980s, however, the amplitude of M2 abruptly dropped. Sea level changes alone appear inadequate to explain either the long-term trend or the recent trend discontinuity. Tidal models that account for Holocene sea level rise do predict an amplification of M2, but much smaller than the currently observed trends. Nor do recent annual mean sea levels correlate with the recent trend discontinuity. Some unknown fraction of the open Atlantic may be similarly affected, since the M2 discontinuity, but not the long-term secular increase in the tide, is evident also at Halifax.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://fl.water.usgs.gov/Abstracts/wri01_4230_knochenmus.html','USGSPUBS'); return false;" href="http://fl.water.usgs.gov/Abstracts/wri01_4230_knochenmus.html"><span>Hydrology of the coastal springs ground-water basin and adjacent parts of Pasco, Hernando, and Citrus Counties, Florida</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Knochenmus, Lari A.; Yobbi, Dann K.</p> <p>2001-01-01</p> <p>The coastal springs in Pasco, Hernando, and Citrus Counties, Florida consist of three first-order magnitude springs and numerous smaller springs, which are points of substantial ground-water discharge from the Upper Floridan aquifer. Spring flow is proportional to the water-level altitude in the aquifer and is affected primarily by the magnitude and timing of rainfall. Ground-water levels in 206 Upper Floridan aquifer wells, and surface-water stage, flow, and specific conductance of water from springs at 10 gaging stations were measured to define the hydrologic variability (temporally and spatially) in the Coastal Springs Ground-Water Basin and adjacent parts of Pasco, Hernando, and Citrus Counties. Rainfall at 46 stations and ground-water withdrawals for three counties, were used to calculate water budgets, to evaluate long-term changes in hydrologic conditions, and to evaluate relations among the hydrologic components. Predictive equations to estimate daily spring flow were developed for eight gaging stations using regression techniques. Regression techniques included ordinary least squares and multiple linear regression techniques. The predictive equations indicate that ground-water levels in the Upper Floridan aquifer are directly related to spring flow. At tidally affected gaging stations, spring flow is inversely related to spring-pool altitude. The springs have similar seasonal flow patterns throughout the area. Water-budget analysis provided insight into the relative importance of the hydrologic components expected to influence spring flow. Four water budgets were constructed for small ground-water basins that form the Coastal Springs Ground-Water Basin. Rainfall averaged 55 inches per year and was the only source of inflow to the Basin. The pathways for outflow were evapotranspiration (34 inches per year), runoff by spring flow (8 inches per year), ground-water outflow from upward leakage (11 inches per year), and ground-water withdrawal (2 inches per year). Recharge (rainfall minus evapotranspiration) to the Upper Floridan aquifer consists of vertical leakage through the surficial deposits. Discharge is primarily through springs and diffuse upward leakage that maintains the extensive swamps along the Gulf of Mexico. The ground-water basins had slightly different partitioning of hydrologic components, reflecting variation among the regions. Trends in hydrologic data were identified using nonparametric statistical techniques to infer long-term changes in hydrologic conditions, and yielded mixed results. No trend in rainfall was detected during the past century. No trend in spring flow was detected in 1931-98. Although monotonic trends were not detected, rainfall patterns are naturally variable from month to month and year to year; this variability is reflected in ground-water levels and spring flows. A decreasing trend in ground-water levels was detected in the Weeki Wachee well (1966-98), but the trend was statistically weak. At current ground-water withdrawal rates, there is no discernible affect on ground-water levels and spring flows. Sporadic data records, lack of continuous data, and inconsistent periods of record among the hydrologic components impeded analysis of long-term changes to the hydrologic system and interrelations among components. The ongoing collection of hydrologic data from index sites could provide much needed information to assess the hydrologic factors affecting the quantity and quality of spring flow in the Coastal Springs Ground-Water Basin.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JASTP.163...46S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JASTP.163...46S"><span>Long term variabilities and tendencies of mesospheric lunar semidiurnal tide over Tirunelveli (8.7°N, 77.8°E)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sathishkumar, S.; Sridharan, S.; Muhammed Kutty, P. V.; Gurubaran, S.</p> <p>2017-10-01</p> <p>The medium frequency radar deployed at Tirunelveli (8.7°N, 77.8°E), which is located near the southmost tip of peninsular India, have been providing continuous data from the year 1993 to the year 2012 that helped to study the long term tendencies in the lunar tidal variabilities over this geographic location. In the present paper we present the results of seasonal, interannual and long-term variabilities of lunar semi-diurnal tides in the upper mesosphere over Tirunelveli. The present study also includes comparison with model values. The study shows that the tidal amplitudes are larger in the meridional components of the mesospheric winds than the zonal winds. The seasonal variations of the tides are similar in both the components. The tides show maximum amplitudes of about ∼5 m/s in February/March, secondary maximum amplitudes of about ∼3 m/s in September and minimum amplitudes during summer months (May-August). The observed seasonal variation of the lunar tides do not compare well with Vial and Forbes (1994) model values, though it is consistent with earlier observations. The lunar tidal phase in meridional winds leads that in zonal winds from January to June and from September to November, while the latter leads the former during July/August. The lunar tides show large interannual variability. There are unusual amplitude enhancements in the lunar tide in meridional winds during the winters of 2006 and 2009, when major sudden stratospheric warmings (SSW) occurred at high latitude northern hemisphere, whereas zonal lunar tide does not show any clear association with the SSW. Vertical wavelengths of lunar tides in zonal and meridional wind are in the range of 20-90 km. The vertical wavelengths of lunar tides in both zonal and meridional component are smaller in June and larger in November and December. The monthly mean zonal and meridional winds are subjected to regression analysis to study the tidal response to long-period oscillations, namely, quasi-biennial oscillation (QBO), solar cycle variation and El-nino southern oscillation (ENSO). It is found the lunar tide in both zonal and meridional winds show significant QBO response, whereas zonal tide only shows significant negative response to solar cycle and positive response to ENSO. Besides, zonal tide only shows significant long-term increasing trend.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.B11C0483M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.B11C0483M"><span>Seasonal, inter-annual and decadal drivers of tree and grass productivity in an Australian tropical savanna.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moore, C.; Beringer, J.; Hutley, L. B.; Evans, B. J.; Tapper, N. J.; Donohue, R. J.; Exbrayat, J. F.</p> <p>2016-12-01</p> <p>Tree-grass savannas are a widespread biome and are highly valued for their ecosystem services. Natural or anthropogenic shifts in the savanna tree-grass ratio have wide-reaching implications for food production, timber harvesting, biodiversity, the water cycle and carbon sequestration. It is important to understand the long-term dynamics and drivers of both tree and grass productivity separately, in order to successfully manage savannas in the future. This study investigates the inter-annual variability (IAV) of tree (overstory) and grass (understory) productivity at the Howard Springs OzFlux/Fluxnet site by combining a long-term (15 year) eddy covariance flux record and DIFFUSE model estimates of tree and grass productivity inferred from satellite remote sensing. On a seasonal basis, the primary drivers of overstory and understory productivity were solar radiation in the wet season and soil moisture in the dry season, with deeper soil layers becoming more important as the dry season progressed. On an inter-annual basis, variability in the amount of annual rainfall and length of the rainy season determined soil water availability, which had a positive effect on overstory productivity and a negative effect on understory productivity. No linear trend in the tree-grass ratio was observed over the 15-year study period, indicating that woody encroachment was not occurring to a significant degree at the study site. However, the tree-grass ratio was well correlated with modes of climate variability, namely the Southern Oscillation Index. This study has provided important insight into the long-term contributions of trees and grasses to savanna productivity, along with the respective drivers of IAV. The results will contribute towards model development and building better links with remote sensing techniques in order to more comprehensively monitor savanna structure and function across space and time.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A22G..01H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A22G..01H"><span>Seasonal, Spatial, and Long-term Variability of Fine Mineral Dust in the United States</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hand, J. L.; White, W. H.; Gebhart, K. A.; Hyslop, N. P.; Gill, T. E.; Schichtel, B. A.</p> <p>2017-12-01</p> <p>Characterizing the seasonal, spatial, and long-term variability of fine mineral dust (FD) is important to assess its environmental and climate impacts. FD concentrations (mineral particles with aerodynamic diameters less than 2.5 µm) were estimated using ambient, ground-based PM2.5 elemental chemistry data from over 160 remote and rural Interagency Monitoring of Protected Visual Environments (IMPROVE) sites from 2011 through 2015. FD concentrations were highest and contributed over 50% of PM2.5 mass at southwestern sites in spring and across the central and southeastern United States in summer (20-30% of PM2.5). The highest seasonal variability in FD occurred at sites in the Southeast during summer, likely associated with impacts from North African transport, which was also evidenced in the elemental ratios of calcium, iron, and aluminum. Long-term trend analyses (2000-2015) indicated widespread, regional increases in FD concentrations during spring in the West, especially in March in the Southwest. This increase was associated with an early onset of the spring dust season and correlated with the Pacific Decadal Oscillation and the El Niño Southern Oscillation. The Southeast and central United States also experienced increased FD concentrations during summer and fall, respectively. Contributions of FD to PM2.5 mass have increased in regions across the United States during all seasons, in part due to increased FD concentrations but also as a result of reductions in secondary aerosols (e.g., sulfates, nitrates, and organic carbon). Increased levels of FD have important implications for its environmental and climate impacts; mitigating these impacts will require identifying and characterizing source regions and underlying mechanisms for dust episodes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRD..12210637P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRD..12210637P"><span>Long-Term Warming Trends in Korea and Contribution of Urbanization: An Updated Assessment</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Park, Bo-Joung; Kim, Yeon-Hee; Min, Seung-Ki; Kim, Maeng-Ki; Choi, Youngeun; Boo, Kyung-On; Shim, Sungbo</p> <p>2017-10-01</p> <p>This study conducted an updated analysis of the long-term temperature trends over South Korea and reassessed the contribution of the urbanization effect to the local warming trends. Linear trends were analyzed for three different periods over South Korea in order to consider possible inhomogeneity due to changes in the number of available stations: recent 103 years (1912-2014), 61 years (1954-2014), and 42 years (1973-2014). The local temperature has increased by 1.90°C, 1.35°C, and 0.99°C during the three periods, respectively, which are found 1.4-2.6 times larger than the global land mean trends. The countries located in the northern middle and high latitudes exhibit similar warming trends (about 1.5 times stronger than the global mean), suggesting a weak influence of urbanization on the local warming over South Korea. Urbanization contribution is assessed using two methods. First, results from "city minus rural" methods showed that 30-45% of the local warming trends during recent four decades are likely due to the urbanization effect, depending on station classification methods and analysis periods. Results from an "observation minus reanalysis" method using the Twentieth Century Reanalysis (20CR) data sets (v2 and v2c) indicated about 25-30% contribution of the urbanization effect to the local warming trend during the recent six decades. However, the urbanization contribution was estimated as low as 3-11% when considering the century-long period. Our results confirm large uncertainties in the estimation of urbanization contribution when using shorter-term periods and suggest that the urbanization contribution to the century-long warming trends could be much lower.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GML....37..515H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GML....37..515H"><span>Evidence for Holocene centennial variability in sea ice cover based on IP25 biomarker reconstruction in the southern Kara Sea (Arctic Ocean)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hörner, Tanja; Stein, Rüdiger; Fahl, Kirsten</p> <p>2017-10-01</p> <p>The Holocene is characterized by the late Holocene cooling trend as well as by internal short-term centennial fluctuations. Because Arctic sea ice acts as a significant component (amplifier) within the climate system, investigating its past long- and short-term variability and controlling processes is beneficial for future climate predictions. This study presents the first biomarker-based (IP25 and PIP25) sea ice reconstruction from the Kara Sea (core BP00-07/7), covering the last 8 ka. These biomarker proxies reflect conspicuous short-term sea ice variability during the last 6.5 ka that is identified unprecedentedly in the source region of Arctic sea ice by means of a direct sea ice indicator. Prominent peaks of extensive sea ice cover occurred at 3, 2, 1.3 and 0.3 ka. Spectral analysis of the IP25 record revealed 400- and 950-year cycles. These periodicities may be related to the Arctic/North Atlantic Oscillation, but probably also to internal climate system fluctuations. This demonstrates that sea ice belongs to a complex system that more likely depends on multiple internal forcing.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JASTP.133...79B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JASTP.133...79B"><span>Tropospheric temperature climatology and trends observed over the Middle East</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Basha, Ghouse; Marpu, P. R.; Ouarda, T. B. M. J.</p> <p>2015-10-01</p> <p>In this study, we report for the first time, the upper air temperature climatology, and trends over the Middle East, which seem to be significantly affected by the changes associated with hot summer and low precipitation. Long term (1985-2012) radiosonde data from 12 stations are used to derive the mean temperature climatology and vertical trends. The study was performed by analyzing the data at different latitudes. The vertical profiles of air temperature show distinct behavior in terms of vertical and seasonal variability at different latitudes. The seasonal cycle of temperature at the 100 hPa, however, shows an opposite pattern compared to the 200 hPa levels. The temperature at 100 hPa shows a maximum during winter and minimum in summer. Spectral analysis shows that the annual cycle is dominant in comparison with the semiannual cycle. The time-series of temperature data was analyzed using the Bayesian change point analysis and cumulative sum method to investigate the changes in temperature trends. Temperature shows a clear change point during the year 1999 at all stations. Further, Modified Mann-Kendall test was applied to study the vertical trend, and analysis shows statistically significant lower tropospheric warming and cooling in upper troposphere after the year 1999. In general, the magnitude of the trend decreases with altitude in the troposphere. In all the latitude bands in lower troposphere, significant warming is observed, whereas at higher altitudes cooling is noticed based on 28 years temperature observations over the Middle East.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.5751C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.5751C"><span>Earth Observation for monitoring phenology for european land use and ecosystems over 1998-2011</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ceccherini, Guido; Gobron, Nadine</p> <p>2013-04-01</p> <p>Long-term measurements of plant phenology have been used to track vegetation responses to climate change but are often limited to particular species and locations and may not represent synoptic patterns. Given the limitations of working directly with in-situ data, many researchers have instead used available satellite remote sensing. Remote sensing extends the possible spatial coverage and temporal range of phenological assessments of environmental change due to the greater availability of observations. Variations and trends of vegetation dynamics are important because they alter the surface carbon, water and energy balance. For example, the net ecosystem CO2 exchange of vegetation is strongly linked to length of the growing season: extentions and decreases in length of growing season modify carbon uptake and the amount of CO2 in the atmosphere. Advances and delays in starting of growing season also affect the surface energy balance and consequently transpiration. The Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) is a key climate variable identified by Global Terrestrial Observing System (GTOS) that can be monitored from space. This dimensionless variable - varying between 0 and 1- is directly linked to the photosynthetic activity of vegetation, and therefore, can monitor changes in phenology. In this study, we identify the spatio/temporal patterns of vegetation dynamics using a long-term remotely sensed FAPAR dataset over Europe. Our aim is to provide a quantitative analysis of vegetation dynamics relevant to climate studies in Europe. As part of this analysis, six vegetation phenological metrics have been defined and made routinely in Europe. Over time, such metrics can track simple, yet critical, impacts of climate change on ecosystems. Validation has been performed through a direct comparison against ground-based data over ecological sites. Subsequently, using the spatio/temporal variability of this suite of metrics, we classify areas with similar vegetation dynamics. This permits assessment of variations and trends of vegetation dynamics over Europe. Statistical tests to assess the significance of temporal changes are used to evaluate trends in the metrics derived from the recorded time series of the FAPAR.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PrOce.161..116O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PrOce.161..116O"><span>Marine heatwaves off eastern Tasmania: Trends, interannual variability, and predictability</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oliver, Eric C. J.; Lago, Véronique; Hobday, Alistair J.; Holbrook, Neil J.; Ling, Scott D.; Mundy, Craig N.</p> <p>2018-02-01</p> <p>Surface waters off eastern Tasmania are a global warming hotspot. Here, mean temperatures have been rising over several decades at nearly four times the global average rate, with concomitant changes in extreme temperatures - marine heatwaves. These changes have recently caused the marine biodiversity, fisheries and aquaculture industries off Tasmania's east coast to come under stress. In this study we quantify the long-term trends, variability and predictability of marine heatwaves off eastern Tasmania. We use a high-resolution ocean model for Tasmania's eastern continental shelf. The ocean state over the 1993-2015 period is hindcast, providing daily estimates of the three-dimensional temperature and circulation fields. Marine heatwaves are identified at the surface and subsurface from ocean temperature time series using a consistent definition. Trends in marine heatwave frequency are positive nearly everywhere and annual marine heatwave days and penetration depths indicate significant positive changes, particularly off southeastern Tasmania. A decomposition into modes of variability indicates that the East Australian Current is the dominant driver of marine heatwaves across the domain. Self-organising maps are used to identify 12 marine heatwave types, each with its own regionality, seasonality, and associated large-scale oceanic and atmospheric circulation patterns. The implications of this work for marine ecosystems and their management were revealed through review of past impacts and stakeholder discussions regarding use of these data.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Geomo.304..184A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Geomo.304..184A"><span>Long-term variability of supratidal coastal boulder activation in Brittany (France)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Autret, Ronan; Dodet, Guillaume; Suanez, Serge; Roudaut, Gildas; Fichaut, Bernard</p> <p>2018-03-01</p> <p>High-energy supratidal coastal boulder deposit (SCBD) dynamics were investigated on Vierge Island and Pors Carn Point, north and south of western Brittany, France, respectively. Morphological changes induced by boulder transport and quarrying were quantified using high-resolution topographic survey data taken between 2012 and 2017. Additional in-situ wave parameters and water levels were also recorded over this period (2014-2017) in order to compute the maximum water levels and assess the relationship between SCBD morphological changes and specific hydrodynamic conditions. During extreme water levels (for maximum water levels exceeding a one in ten year event), SCBDs were broadly reworked (up to 40% of the total volume). During lower intensity events, for which maximum water levels were still very high, morphological changes represented 1% to 5% of the total volume. These morphological and hydrodynamic observations were then used to calibrate a chronology of SCBD activation events based on 70 years of hindcast winter maximum water levels. These long-term time-series showed great interannual variability in SCBD activation but no significant long-term trend. Winter-frequency SCBD activation was better correlated to the WEPA index (r = 0.46) than the NAO index (r = 0.1). Therefore, the WEPA index can be considered to be a more significant climate proxy for assessing storm-related geomorphic changes in the temperate latitudes of the N-E Atlantic basin (36°-52° N), including the Brittany coast. The potential of SCBDs as a morphological storm proxy for macrotidal high-energy rocky coasts is addressed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20060028087','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20060028087"><span>Tropical Rainfall Variability on Interannual-to-Interdecadal/Longer-Time Scales Derived from the GPCP Monthly Product</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gu, Guojun; Adler, Robert F.; Huffman, George J.; Curtis, Scott</p> <p>2006-01-01</p> <p>Global and large regional rainfall variations and possible long-term changes are examined using the 26-year (1979-2004) GPCP monthly dataset (Adler et al., 2003). Our emphasis is to discriminate among variations due to ENSO, volcanic events, and possible long-term climate changes in the tropics. Although the global linear change of precipitation in the data set is near zero during the time period, an increase in tropical rainfall is noted, with a weaker decrease over northern hemisphere middle latitudes. Focusing on the tropics (25degS-25degN), the data set indicates an upward trend (0.06 mm/day/decade) and a downward trend (-0.02 mm/day/decade) over tropical ocean and land, respectively. This corresponds to an about 4.9% increase (ocean) and 1.6% decrease (land) during the entire 26-year time period. Techniques are applied to isolate and quantify variations due to ENSO and two major volcanic eruptions (El Chichon, March 1982; Pinatubo, June 1991) in order to examine longer time-scale changes. The ENSO events generally do not impact the tropical total rainfall, but, of course, induce significant anomalies with opposite signs over tropical land and ocean. The impact of the two volcanic eruptions is estimated to be about a 5% reduction in tropical rainfall over both land and ocean. A modified data set (with ENSO and volcano effects removed) retains the same approximate linear change slopes, but with reduced variance, thereby increasing the confidence levels associated with the long-term rainfall changes in the tropics 2</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70030124','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70030124"><span>Surface temperature patterns in complex terrain: Daily variations and long-term change in the central Sierra Nevada, California</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lundquist, J.D.; Cayan, D.R.</p> <p>2007-01-01</p> <p>A realistic description of how temperatures vary with elevation is crucial for ecosystem studies and for models of basin-scale snowmelt and spring streamflow. This paper explores surface temperature variability using temperature data from an array of 37 sensors, called the Yosemite network, which traverses both slopes of the Sierra Nevada in the vicinity of Yosemite National Park, California. These data indicate that a simple lapse rate is often a poor description of the spatial temperature structure. Rather, the spatial pattern of temperature over the Yosemite network varies considerably with synoptic conditions. Empirical orthogonal functions (EOFs) were used to identify the dominant spatial temperature patterns and how they vary in time. Temporal variations of these surface temperature patterns were correlated with large-scale weather conditions, as described by National Centers for Environmental Prediction-National Center for Atmospheric Research Reanalysis data. Regression equations were used to downscale larger-scale weather parameters, such as Reanalysis winds and pressure, to the surface temperature structure over the Yosemite network. These relationships demonstrate that strong westerly winds are associated with relatively warmer temperatures on the east slope and cooler temperatures on the west slope of the Sierra, and weaker westerly winds are associated with the opposite pattern. Reanalysis data from 1948 to 2005 indicate weakening westerlies over this time period, a trend leading to relatively cooler temperatures on the east slope over decadal timescale's. This trend also appears in long-term observations and demonstrates the need to consider topographic effects when examining long-term changes in mountain regions. Copyright 2007 by the American Geophysical Union.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20959156','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20959156"><span>Temporal change in deep-sea benthic ecosystems: a review of the evidence from recent time-series studies.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Glover, A G; Gooday, A J; Bailey, D M; Billett, D S M; Chevaldonné, P; Colaço, A; Copley, J; Cuvelier, D; Desbruyères, D; Kalogeropoulou, V; Klages, M; Lampadariou, N; Lejeusne, C; Mestre, N C; Paterson, G L J; Perez, T; Ruhl, H; Sarrazin, J; Soltwedel, T; Soto, E H; Thatje, S; Tselepides, A; Van Gaever, S; Vanreusel, A</p> <p>2010-01-01</p> <p>Societal concerns over the potential impacts of recent global change have prompted renewed interest in the long-term ecological monitoring of large ecosystems. The deep sea is the largest ecosystem on the planet, the least accessible, and perhaps the least understood. Nevertheless, deep-sea data collected over the last few decades are now being synthesised with a view to both measuring global change and predicting the future impacts of further rises in atmospheric carbon dioxide concentrations. For many years, it was assumed by many that the deep sea is a stable habitat, buffered from short-term changes in the atmosphere or upper ocean. However, recent studies suggest that deep-seafloor ecosystems may respond relatively quickly to seasonal, inter-annual and decadal-scale shifts in upper-ocean variables. In this review, we assess the evidence for these long-term (i.e. inter-annual to decadal-scale) changes both in biologically driven, sedimented, deep-sea ecosystems (e.g. abyssal plains) and in chemosynthetic ecosystems that are partially geologically driven, such as hydrothermal vents and cold seeps. We have identified 11 deep-sea sedimented ecosystems for which published analyses of long-term biological data exist. At three of these, we have found evidence for a progressive trend that could be potentially linked to recent climate change, although the evidence is not conclusive. At the other sites, we have concluded that the changes were either not significant, or were stochastically variable without being clearly linked to climate change or climate variability indices. For chemosynthetic ecosystems, we have identified 14 sites for which there are some published long-term data. Data for temporal changes at chemosynthetic ecosystems are scarce, with few sites being subjected to repeated visits. However, the limited evidence from hydrothermal vents suggests that at fast-spreading centres such as the East Pacific Rise, vent communities are impacted on decadal scales by stochastic events such as volcanic eruptions, with associated fauna showing complex patterns of community succession. For the slow-spreading centres such as the Mid-Atlantic Ridge, vent sites appear to be stable over the time periods measured, with no discernable long-term trend. At cold seeps, inferences based on spatial studies in the Gulf of Mexico, and data on organism longevity, suggest that these sites are stable over many hundreds of years. However, at the Haakon Mosby mud volcano, a large, well-studied seep in the Barents Sea, periodic mud slides associated with gas and fluid venting may disrupt benthic communities, leading to successional sequences over time. For chemosynthetic ecosystems of biogenic origin (e.g. whale-falls), it is likely that the longevity of the habitat depends mainly on the size of the carcass and the ecological setting, with large remains persisting as a distinct seafloor habitat for up to 100 years. Studies of shallow-water analogs of deep-sea ecosystems such as marine caves may also yield insights into temporal processes. Although it is obvious from the geological record that past climate change has impacted deep-sea faunas, the evidence that recent climate change or climate variability has altered deep-sea benthic communities is extremely limited. This mainly reflects the lack of remote sensing of this vast seafloor habitat. Current and future advances in deep-ocean benthic science involve new remote observing technologies that combine a high temporal resolution (e.g. cabled observatories) with spatial capabilities (e.g. autonomous vehicles undertaking image surveys of the seabed). Copyright © 2010 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29466354','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29466354"><span>Identification of long-term trends and seasonality in high-frequency water quality data from the Yangtze River basin, China.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Duan, Weili; He, Bin; Chen, Yaning; Zou, Shan; Wang, Yi; Nover, Daniel; Chen, Wen; Yang, Guishan</p> <p>2018-01-01</p> <p>Comprehensive understanding of the long-term trends and seasonality of water quality is important for controlling water pollution. This study focuses on spatio-temporal distributions, long-term trends, and seasonality of water quality in the Yangtze River basin using a combination of the seasonal Mann-Kendall test and time-series decomposition. The used weekly water quality data were from 17 environmental stations for the period January 2004 to December 2015. Results show gradual improvement in water quality during this period in the Yangtze River basin and greater improvement in the Uppermost Yangtze River basin. The larger cities, with high GDP and population density, experienced relatively higher pollution levels due to discharge of industrial and household wastewater. There are higher pollution levels in Xiang and Gan River basins, as indicated by higher NH4-N and CODMn concentrations measured at the stations within these basins. Significant trends in water quality were identified for the 2004-2015 period. Operations of the three Gorges Reservoir (TGR) enhanced pH fluctuations and possibly attenuated CODMn, and NH4-N transportation. Finally, seasonal cycles of varying strength were detected for time-series of pollutants in river discharge. Seasonal patterns in pH indicate that maxima appear in winter, and minima in summer, with the opposite true for CODMn. Accurate understanding of long-term trends and seasonality are necessary goals of water quality monitoring system efforts and the analysis methods described here provide essential information for effectively controlling water pollution.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ChJOL..33.1233J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ChJOL..33.1233J"><span>Modal recovery of sea-level variability in the South China Sea using merged altimeter data</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jiang, Haoyu; Chen, Ge</p> <p>2015-09-01</p> <p>Using 20 years (1993-2012) of merged data recorded by contemporary multi-altimeter missions, a variety of sea-level variability modes are recovered in the South China Sea employing three-dimensional harmonic extraction. In terms of the long-term variation, the South China Sea is estimated to have a rising sea-level linear trend of 5.39 mm/a over these 20 years. Among the modes extracted, the seven most statistically significant periodic or quasi-periodic modes are identified as principal modes. The geographical distributions of the magnitudes and phases of the modes are displayed. In terms of intraannual and annual regimes, two principal modes with strict semiannual and annual periods are found, with the annual variability having the largest amplitudes among the seven modes. For interannual and decadal regimes, five principal modes at approximately 18, 21, 23, 28, and 112 months are found with the most mode-active region being to the east of Vietnam. For the phase distributions, a series of amphidromes are observed as twins, termed "amphidrome twins", comprising rotating dipole systems. The stability of periodic modes is investigated employing joint spatiotemporal analysis of latitude/longitude sections. Results show that all periodic modes are robust, revealing the richness and complexity of sea-level modes in the South China Sea.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70192442','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70192442"><span>Groundwater level trends and drivers in two northern New England glacial aquifers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Shanley, James B.; Chalmers, Ann T.; Mack, Thomas J.; Smith, Thor E.; Harte, Philip T.</p> <p>2016-01-01</p> <p>We evaluated long-term trends and predictors of groundwater levels by month from two well-studied northern New England forested headwater glacial aquifers: Sleepers River, Vermont, 44 wells, 1992-2013; and Hubbard Brook, New Hampshire, 15 wells, 1979-2004. Based on Kendall Tau tests with Sen slope determination, a surprising number of well-month combinations had negative trends (decreasing water levels) over the respective periods. Sleepers River had slightly more positive than negative trends overall, but among the significant trends (p < 0.1), negative trends dominated 67 to 40. At Hubbard Brook, negative trends outnumbered positive trends by a nearly 2:1 margin and all seven of the significant trends were negative. The negative trends occurred despite generally increasing trends in monthly and annual precipitation. This counterintuitive pattern may be a result of increased precipitation intensity causing higher runoff at the expense of recharge, such that evapotranspiration demand draws down groundwater storage. We evaluated predictors of month-end water levels by multiple regression of 18 variables related to climate, streamflow, snowpack, and prior month water level. Monthly flow and prior month water level were the two strongest predictors for most months at both sites. The predictive power and ready availability of streamflow data can be exploited as a proxy to extend limited groundwater level records over longer time periods.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1072048','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1072048"><span>A social systems model of nursing home use.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wolf, R S</p> <p>1978-01-01</p> <p>Causal modeling (path analysis) was applied to data from the 39 mental health catchment areas of Massachusetts to analyze the effects of sociocultural and health-resource variables on long-term-care utilization. The variables chosen explained 53 percent of the variance of long-term-care use by persons 60 and older: 41 percent was explained by the sociocultural variables and 12 percent by the health-resource variables. With data adjusted for age, the major determinant of long-term-care use was ethnicity: less long-term care was used in areas with more persons who were foreign-born or had a foreign-born parent. The effects of other health resources (supply of primary care physicians and use of mental and general (short-term) hospitals) were small and negative. PMID:418027</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H51T..01P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H51T..01P"><span>The Climate-Population Nexus in the East African Horn: Emerging Degradation Trends in Rangeland and Pastoral Livelihood Zones</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pricope, N. G.; Husak, G. J.; Funk, C. C.; Lopez-Carr, D.</p> <p>2014-12-01</p> <p>Increasing climate variability and extreme weather conditions along with declining trends in both rainfall and temperature represent major risk factors affecting agricultural production and food security in many regions of the world. We identify regions where significant rainfall decrease from 1979-2011 over the entire continent of Africa couples with significant human population density increase. The rangelands of Ethiopia, Kenya, and Somalia in the East African Horn remain one of the world's most food insecure regions, yet have significantly increasing human populations predominantly dependent on pastoralist and agro-pastoralist livelihoods. Vegetation in this region is characterized by a variable mosaic of land covers, generally dominated by grasslands necessary for agro-pastoralism, interspersed by woody vegetation. Recent assessments indicate that widespread degradation is occurring, adversely impacting fragile ecosystems and human livelihoods. Using two underutilized MODIS products, we observe significant changes in vegetation patterns and productivity over the last decade all across the East African Horn. We observe significant vegetation browning trends in areas experiencing drying precipitation trends in addition to increasing population pressures. We also found that the drying precipitation trends only partially statistically explain the vegetation browning trends, further indicating that other factors such as population pressures and land use changes are responsible for the observed declining vegetation health. Furthermore, we show that the general vegetation browning trends persist even during years with normal rainfall conditions such as 2012, indicating potential long-term degradation of rangelands on which approximately 10 million people depend. These findings have serious implications for current and future regional food security monitoring and forecasting as well as for mitigation and adaptation strategies in a region where population is expected to continue increasing against a backdrop of drying climate trends.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950004223','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950004223"><span>On long-term ozone trends at Hohenpeissenberg</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Claude, H.; Vandersee, W.; Wege, K.</p> <p>1994-01-01</p> <p>More than 2000 ozone soundings and a large number of Dobson observations have been performed since 1967 in a unique procedure. The achieved very homogeneous data sets were used to evaluate significant long-term trends both in the troposphere and the stratosphere. The trend amounts to about plus 2 percent per year in the troposphere and to about minus 0.5 percent per year in the stratosphere. Extremely low ozone records obtained during winter 1991/92 are discussed in the light of the long term series. The winter mean of the ozone column is the lowest one of the series. The ozone deficit occurred mainly in the lower stratosphere. One cause may be the Pinatubo cloud. Even compared with the extreme winter mean following the El Chichon eruption the ozone content was lower. Additionally ozone was reduced by dynamical effects due to unusual weather situations.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/285207-extended-rotations-culmination-age-coast-douglas-fir-old-studies-speak-current-issues-forest-service-research-paper','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/285207-extended-rotations-culmination-age-coast-douglas-fir-old-studies-speak-current-issues-forest-service-research-paper"><span>Extended rotations and culmination age of coast douglas-fir: Old studies speak to current issues. Forest Service research paper</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Curtis, R.O.</p> <p>1995-11-01</p> <p>Trends of mean annual increment and periodic annual increment were examined in 17 long-term thinning studies in Douglas-fir (Pseuditsuga menziesii var. menziesii (Mirb.) Franco) in western Washington, western Oregon, and British Columbia. Problems in evaluating growth trends and culmination ages are discussed. None of the stands had clearly reached culmination of mean annual increment, although some seemed close. The observed trends seem generally consistent with some other recent comparisons. These comparisons indicate that rotations can be considerably extended without reducing long-term timber production; value production probably would increase. A major problem in such a strategy is design of thinning regimesmore » that can maintain a reasonable level of timber flow during the transition period while producing stand conditions compatible with other management objectives. The continuing value of long-term permanent plot studies is emphasized.« less</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <div class="footer-extlink text-muted" style="margin-bottom:1rem; text-align:center;">Some links on this page may take you to non-federal websites. 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