Sample records for warm season months

  1. Enhanced seasonal forecast skill following stratospheric sudden warmings

    NASA Astrophysics Data System (ADS)

    Sigmond, M.; Scinocca, J. F.; Kharin, V. V.; Shepherd, T. G.

    2013-02-01

    Advances in seasonal forecasting have brought widespread socio-economic benefits. However, seasonal forecast skill in the extratropics is relatively modest, prompting the seasonal forecasting community to search for additional sources of predictability. For over a decade it has been suggested that knowledge of the state of the stratosphere can act as a source of enhanced seasonal predictability; long-lived circulation anomalies in the lower stratosphere that follow stratospheric sudden warmings are associated with circulation anomalies in the troposphere that can last up to two months. Here, we show by performing retrospective ensemble model forecasts that such enhanced predictability can be realized in a dynamical seasonal forecast system with a good representation of the stratosphere. When initialized at the onset date of stratospheric sudden warmings, the model forecasts faithfully reproduce the observed mean tropospheric conditions in the months following the stratospheric sudden warmings. Compared with an equivalent set of forecasts that are not initialized during stratospheric sudden warmings, we document enhanced forecast skill for atmospheric circulation patterns, surface temperatures over northern Russia and eastern Canada and North Atlantic precipitation. We suggest that seasonal forecast systems initialized during stratospheric sudden warmings are likely to yield significantly greater forecast skill in some regions.

  2. Using cloud and climate data to understand warm season hydrometeorology from diurnal to monthly timescales

    NASA Astrophysics Data System (ADS)

    Betts, A. K.; Tawfik, A. B.; Desjardins, R. L.

    2016-12-01

    We use 600 station years of hourly data from 14 stations on the Canadian Prairies to map the warm season hydrometeorology. The months from April (after snowmelt) to September, have a very similar coupling between surface thermodynamics and opaque cloud cover, which has been calibrated to give cloud radiative forcing. We can derive both the mean diurnal ranges and the diurnal imbalances as a function of opaque cloud cover. For the monthly diurnal climate, we compute the coupling coefficients with opaque cloud cover and lagged precipitation. In April the diurnal cycle climate has memory of precipitation back to freeze-up in November. During the growing season months of June, July and August, there is memory of precipitation back to March. Monthly mean temperature depends strongly on cloud but little on precipitation, while monthly mean mixing ratio depends on precipitation, but rather little on cloud. The coupling coefficients to cloud and precipitation change with increasing monthly precipitation anomaly. This observational climate analysis provides a firm basis for model evaluation.

  3. The importance of warm season warming to western U.S. streamflow changes

    USGS Publications Warehouse

    Das, T.; Pierce, D.W.; Cayan, D.R.; Vano, J.A.; Lettenmaier, D.P.

    2011-01-01

    Warm season climate warming will be a key driver of annual streamflow changes in four major river basins of the western U.S., as shown by hydrological model simulations using fixed precipitation and idealized seasonal temperature changes based on climate projections with SRES A2 forcing. Warm season (April-September) warming reduces streamflow throughout the year; streamflow declines both immediately and in the subsequent cool season. Cool season (October-March) warming, by contrast, increases streamflow immediately, partially compensating for streamflow reductions during the subsequent warm season. A uniform warm season warming of 3C drives a wide range of annual flow declines across the basins: 13.3%, 7.2%, 1.8%, and 3.6% in the Colorado, Columbia, Northern and Southern Sierra basins, respectively. The same warming applied during the cool season gives annual declines of only 3.5%, 1.7%, 2.1%, and 3.1%, respectively. Copyright 2011 by the American Geophysical Union.

  4. Assessment of long-term monthly and seasonal trends of warm (cold), wet (dry) spells in Kansas, USA

    NASA Astrophysics Data System (ADS)

    Dokoohaki, H.; Anandhi, A.

    2013-12-01

    A few recent studies have focused on trends in rainfall, temperature, and frost indicators at different temporal scales using centennial weather station data in Kansas; our study supplements this work by assessing the changes in spell indicators in Kansas. These indicators provide the duration between temperature-based (warm and cold) and precipitation-based (wet and dry) spells. For wet (dry) spell calculations, a wet day is defined as a day with precipitation ≥1 mm, and a dry day is defined as one with precipitation ≤1 mm. For warm (cold) spell calculations, a warm day is defined as a day with maximum temperature >90th percentile of daily maximum temperature, and a cold day is defined as a day with minimum temperature <10th percentile of daily minimum temperature. The percentiles are calculated for 1971-2000, and four spell indicators are calculated: Average Wet Spell Length (AWSL), Dry Spell Length (ADSL), Average Warm Spell Days (AWSD) and Average Cold Spell Days (ACSD) are calculated. Data were provided from 23 centennial weather stations across Kansas, and all calculations were done for four time periods (through 1919, 1920-1949, 1950-1979, and 1980-2009). The definitions and software provided by Expert Team on Climate Change Detection and Indices (ETCCDI) were adapted for application to Kansas. The long- and short-term trends in these indices were analyzed at monthly and seasonal timescales. Monthly results indicate that ADSL is decreasing and AWSL is increasing throughout the state. AWSD and ACSD both showed an overall decreasing trend, but AWSD trends were variable during the beginning of the Industrial Revolution. Results of seasonal analysis revealed that the fall season recorded the greatest increasing trend for ACSD and the greatest decreasing trend for AWSD across the whole state and during all time periods. Similarly, the greatest increasing and decreasing trends occurred in winter for AWSL and ADSL, respectively. These variations can be

  5. Seasonality of change: Summer warming rates do not fully represent effects of climate change on lake temperatures

    USGS Publications Warehouse

    Winslow, Luke; Read, Jordan S.; Hansen, Gretchen J. A.; Rose, Kevin C.; Robertson, Dale M.

    2017-01-01

    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.

  6. Small mammal use of native warm-season and non-native cool-season grass forage fields

    USGS Publications Warehouse

    Ryan L Klimstra,; Christopher E Moorman,; Converse, Sarah J.; Royle, J. Andrew; Craig A Harper,

    2015-01-01

    Recent emphasis has been put on establishing native warm-season grasses for forage production because it is thought native warm-season grasses provide higher quality wildlife habitat than do non-native cool-season grasses. However, it is not clear whether native warm-season grass fields provide better resources for small mammals than currently are available in non-native cool-season grass forage production fields. We developed a hierarchical spatially explicit capture-recapture model to compare abundance of hispid cotton rats (Sigmodon hispidus), white-footed mice (Peromyscus leucopus), and house mice (Mus musculus) among 4 hayed non-native cool-season grass fields, 4 hayed native warm-season grass fields, and 4 native warm-season grass-forb ("wildlife") fields managed for wildlife during 2 summer trapping periods in 2009 and 2010 of the western piedmont of North Carolina, USA. Cotton rat abundance estimates were greater in wildlife fields than in native warm-season grass and non-native cool-season grass fields and greater in native warm-season grass fields than in non-native cool-season grass fields. Abundances of white-footed mouse and house mouse populations were lower in wildlife fields than in native warm-season grass and non-native cool-season grass fields, but the abundances were not different between the native warm-season grass and non-native cool-season grass fields. Lack of cover following haying in non-native cool-season grass and native warm-season grass fields likely was the key factor limiting small mammal abundance, especially cotton rats, in forage fields. Retention of vegetation structure in managed forage production systems, either by alternately resting cool-season and warm-season grass forage fields or by leaving unharvested field borders, should provide refugia for small mammals during haying events.

  7. Regional seasonal warming anomalies and land-surface feedbacks

    NASA Astrophysics Data System (ADS)

    Coffel, E.; Horton, R. M.

    2017-12-01

    Significant seasonal variations in warming are projected in some regions, especially central Europe, the southeastern U.S., and central South America. Europe in particular may experience up to 2°C more warming during June, July, and August than in the annual mean, enhancing the risk of extreme summertime heat. Previous research has shown that heat waves in Europe and other regions are tied to seasonal soil moisture variations, and that in general land-surface feedbacks have a strong effect on seasonal temperature anomalies. In this study, we show that the seasonal anomalies in warming are also due in part to land-surface feedbacks. We find that in regions with amplified warming during the hot season, surface soil moisture levels generally decline and Bowen ratios increase as a result of a preferential partitioning of incoming energy into sensible vs. latent. The CMIP5 model suite shows significant variability in the strength of land-atmosphere coupling and in projections of future precipitation and soil moisture. Due to the dependence of seasonal warming on land-surface processes, these inter-model variations influence the projected summertime warming amplification and contribute to the uncertainty in projections of future extreme heat.

  8. Establishing native warm season grasses on Eastern Kentucky strip mines

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Barnes, T.G.; Larkin, J.L.; Arnett, M.B.

    1998-12-31

    The authors evaluated various methods of establishing native warm season grasses on two reclaimed Eastern Kentucky mines from 1994--1997. Most current reclamation practices incorporate the use of tall fescue (Festuca arundinacea) and other cool-season grasses/legumes that provide little wildlife habitats. The use of native warm season grasses will likely improve wildlife habitat on reclaimed strip mines. Objectives of this study were to compare the feasibility of establishing these grasses during fall, winter, or spring using a native rangeland seeder or hydroseeding; a fertilizer application at planting; or cold-moist stratification prior to hydroseeding. Vegetative cover, bare ground, species richness, and biomassmore » samples were collected at the end of each growing season. Native warm season grass plantings had higher plant species richness compared to cool-season reclamation mixtures. There was no difference in establishment of native warm season grasses as a result of fertilization or seeding technique. Winter native warm season grass plantings were failures and cold-moist stratification did not increase plant establishment during any season. As a result of a drought during 1997, both cool-season and warm season plantings were failures. Cool-season reclamation mixtures had significantly more vegetative cover and biomass compared to native warm season grass mixtures and the native warm season grass plantings did not meet vegetative cover requirements for bond release. Forbs and legumes that established well included pale purple coneflower (Echinacea pallida), lance-leaf coreopsis (Coreopsis lanceolata), round-headed lespedeza (Lespedeza capitata), partridge pea (Cassia fasiculata), black-eyed susan (Rudbeckia hirta), butterfly milkweed (Asclepias tuberosa), and bergamot (Monarda fistulosa). Results from two demonstration plots next to research plots indicate it is possible to establish native warm season grasses on Eastern Kentucky strip mines for wildlife

  9. Winter Season Mortality: Will Climate Warming Bring Benefits?

    PubMed

    Kinney, Patrick L; Schwartz, Joel; Pascal, Mathilde; Petkova, Elisaveta; Tertre, Alain Le; Medina, Sylvia; Vautard, Robert

    2015-06-01

    Extreme heat events are associated with spikes in mortality, yet death rates are on average highest during the coldest months of the year. Under the assumption that most winter excess mortality is due to cold temperature, many previous studies have concluded that winter mortality will substantially decline in a warming climate. We analyzed whether and to what extent cold temperatures are associated with excess winter mortality across multiple cities and over multiple years within individual cities, using daily temperature and mortality data from 36 US cities (1985-2006) and 3 French cities (1971-2007). Comparing across cities, we found that excess winter mortality did not depend on seasonal temperature range, and was no lower in warmer vs. colder cities, suggesting that temperature is not a key driver of winter excess mortality. Using regression models within monthly strata, we found that variability in daily mortality within cities was not strongly influenced by winter temperature. Finally we found that inadequate control for seasonality in analyses of the effects of cold temperatures led to spuriously large assumed cold effects, and erroneous attribution of winter mortality to cold temperatures. Our findings suggest that reductions in cold-related mortality under warming climate may be much smaller than some have assumed. This should be of interest to researchers and policy makers concerned with projecting future health effects of climate change and developing relevant adaptation strategies.

  10. Winter season mortality: will climate warming bring benefits?

    NASA Astrophysics Data System (ADS)

    Kinney, Patrick L.; Schwartz, Joel; Pascal, Mathilde; Petkova, Elisaveta; Le Tertre, Alain; Medina, Sylvia; Vautard, Robert

    2015-06-01

    Extreme heat events are associated with spikes in mortality, yet death rates are on average highest during the coldest months of the year. Under the assumption that most winter excess mortality is due to cold temperature, many previous studies have concluded that winter mortality will substantially decline in a warming climate. We analyzed whether and to what extent cold temperatures are associated with excess winter mortality across multiple cities and over multiple years within individual cities, using daily temperature and mortality data from 36 US cities (1985-2006) and 3 French cities (1971-2007). Comparing across cities, we found that excess winter mortality did not depend on seasonal temperature range, and was no lower in warmer vs. colder cities, suggesting that temperature is not a key driver of winter excess mortality. Using regression models within monthly strata, we found that variability in daily mortality within cities was not strongly influenced by winter temperature. Finally we found that inadequate control for seasonality in analyses of the effects of cold temperatures led to spuriously large assumed cold effects, and erroneous attribution of winter mortality to cold temperatures. Our findings suggest that reductions in cold-related mortality under warming climate may be much smaller than some have assumed. This should be of interest to researchers and policy makers concerned with projecting future health effects of climate change and developing relevant adaptation strategies.

  11. Global warming induced hybrid rainy seasons in the Sahel

    NASA Astrophysics Data System (ADS)

    Salack, Seyni; Klein, Cornelia; Giannini, Alessandra; Sarr, Benoit; Worou, Omonlola N.; Belko, Nouhoun; Bliefernicht, Jan; Kunstman, Harald

    2016-10-01

    The small rainfall recovery observed over the Sahel, concomitant with a regional climate warming, conceals some drought features that exacerbate food security. The new rainfall features include false start and early cessation of rainy seasons, increased frequency of intense daily rainfall, increasing number of hot nights and warm days and a decreasing trend in diurnal temperature range. Here, we explain these mixed dry/wet seasonal rainfall features which are called hybrid rainy seasons by delving into observed data consensus on the reduction in rainfall amount, its spatial coverage, timing and erratic distribution of events, and other atmospheric variables crucial in agro-climatic monitoring and seasonal forecasting. Further composite investigations of seasonal droughts, oceans warming and the regional atmospheric circulation nexus reveal that the low-to-mid-level atmospheric winds pattern, often stationary relative to either strong or neutral El-Niño-Southern-Oscillations drought patterns, associates to basin warmings in the North Atlantic and the Mediterranean Sea to trigger hybrid rainy seasons in the Sahel. More challenging to rain-fed farming systems, our results suggest that these new rainfall conditions will most likely be sustained by global warming, reshaping thereby our understanding of food insecurity in this region.

  12. Cellulosic ethanol production from warm-season perennial grasses

    USDA-ARS?s Scientific Manuscript database

    Warm-season (C4) perennial grasses are able to produce large quantities of biomass, and will play a key role in bioenergy production, particularly in areas with long warm growing seasons. Several different grass species have been studied as candidate bioenergy crops for the Southeast USA, and each ...

  13. The seasonal timing of warming that controls onset of the growing season.

    PubMed

    Clark, James S; Melillo, Jerry; Mohan, Jacqueline; Salk, Carl

    2014-04-01

    Forecasting how global warming will affect onset of the growing season is essential for predicting terrestrial productivity, but suffers from conflicting evidence. We show that accurate estimates require ways to connect discrete observations of changing tree status (e.g., pre- vs. post budbreak) with continuous responses to fluctuating temperatures. By coherently synthesizing discrete observations with continuous responses to temperature variation, we accurately quantify how increasing temperature variation accelerates onset of growth. Application to warming experiments at two latitudes demonstrates that maximum responses to warming are concentrated in late winter, weeks ahead of the main budbreak period. Given that warming will not occur uniformly over the year, knowledge of when temperature variation has the most impact can guide prediction. Responses are large and heterogeneous, yet predictable. The approach has immediate application to forecasting effects of warming on growing season length, requiring only information that is readily available from weather stations and generated in climate models. © 2013 John Wiley & Sons Ltd.

  14. Elevated CO2 further lengthens growing season under warming conditions.

    PubMed

    Reyes-Fox, Melissa; Steltzer, Heidi; Trlica, M J; McMaster, Gregory S; Andales, Allan A; LeCain, Dan R; Morgan, Jack A

    2014-06-12

    Observations of a longer growing season through earlier plant growth in temperate to polar regions have been thought to be a response to climate warming. However, data from experimental warming studies indicate that many species that initiate leaf growth and flowering earlier also reach seed maturation and senesce earlier, shortening their active and reproductive periods. A conceptual model to explain this apparent contradiction, and an analysis of the effect of elevated CO2--which can delay annual life cycle events--on changing season length, have not been tested. Here we show that experimental warming in a temperate grassland led to a longer growing season through earlier leaf emergence by the first species to leaf, often a grass, and constant or delayed senescence by other species that were the last to senesce, supporting the conceptual model. Elevated CO2 further extended growing, but not reproductive, season length in the warmed grassland by conserving water, which enabled most species to remain active longer. Our results suggest that a longer growing season, especially in years or biomes where water is a limiting factor, is not due to warming alone, but also to higher atmospheric CO2 concentrations that extend the active period of plant annual life cycles.

  15. Projected warming portends seasonal shifts of stream temperatures in the Crown of the Continent Ecosystem, USA and Canada

    USGS Publications Warehouse

    Jones, Leslie A.; Muhlfeld, Clint C.; Marshall, Lucy A.

    2017-01-01

    Climate warming is expected to increase stream temperatures in mountainous regions of western North America, yet the degree to which future climate change may influence seasonal patterns of stream temperature is uncertain. In this study, a spatially explicit statistical model framework was integrated with empirical stream temperature data (approximately four million bi-hourly recordings) and high-resolution climate and land surface data to estimate monthly stream temperatures and potential change under future climate scenarios in the Crown of the Continent Ecosystem, USA and Canada (72,000 km2). Moderate and extreme warming scenarios forecast increasing stream temperatures during spring, summer, and fall, with the largest increases predicted during summer (July, August, and September). Additionally, thermal regimes characteristic of current August temperatures, the warmest month of the year, may be exceeded during July and September, suggesting an earlier and extended duration of warm summer stream temperatures. Models estimate that the largest magnitude of temperature warming relative to current conditions may be observed during the shoulder months of winter (April and November). Summer stream temperature warming is likely to be most pronounced in glacial-fed streams where models predict the largest magnitude (> 50%) of change due to the loss of alpine glaciers. We provide the first broad-scale analysis of seasonal climate effects on spatiotemporal patterns of stream temperature in the Crown of the Continent Ecosystem for better understanding climate change impacts on freshwater habitats and guiding conservation and climate adaptation strategies.

  16. Seasonal warming of the Middle Atlantic Bight Cold Pool

    NASA Astrophysics Data System (ADS)

    Lentz, S. J.

    2017-02-01

    The Cold Pool is a 20-60 m thick band of cold, near-bottom water that persists from spring to fall over the midshelf and outer shelf of the Middle Atlantic Bight (MAB) and Southern Flank of Georges Bank. The Cold Pool is remnant winter water bounded above by the seasonal thermocline and offshore by warmer slope water. Historical temperature profiles are used to characterize the average annual evolution and spatial structure of the Cold Pool. The Cold Pool gradually warms from spring to summer at a rate of order 1°C month-1. The warming rate is faster in shallower water where the Cold Pool is thinner, consistent with a vertical turbulent heat flux from the thermocline to the Cold Pool. The Cold Pool warming rate also varies along the shelf; it is larger over Georges Bank and smaller in the southern MAB. The mean turbulent diffusivities at the top of the Cold Pool, estimated from the spring to summer mean heat balance, are an order of magnitude larger over Georges Bank than in the southern MAB, consistent with much stronger tidal mixing over Georges Bank than in the southern MAB. The stronger tidal mixing causes the Cold Pool to warm more rapidly over Georges Bank and the eastern New England shelf than in the New York Bight or southern MAB. Consequently, the coldest Cold Pool water is located in the New York Bight from late spring to summer.

  17. [Comparative evaluation of heat state in workers exposed to heating microclimate during cold and warm seasons].

    PubMed

    Afanas'eva, R F; Prokopenko, L V; Kiladze, N A; Konstantinov, E I

    2009-01-01

    The authors demonstrated differences in heat state among workers exposed to heating microclimate during cold and warm seasons. Same external thermal load in cold season induces more humidity loss, lower weighted average skin temperature, higher pulse rate, increased systolic and diastolic blood pressure. With that, heat discomfort was more in cold season, than in warm one, this necessitates decrease of thermal load in cold season vs. the warm one.

  18. Characterizing the Seasonality and Spatiotemporal Evolution of the U.S. Warming Hole

    NASA Astrophysics Data System (ADS)

    Partridge, T.; Winter, J.; Osterberg, E. C.; Magilligan, F. J.; Hyndman, D. W.; Kendall, A. D.

    2017-12-01

    Regions of the Eastern United States have experienced periods of cooling during the last half of the twentieth century inconsistent with broader global warming trends. While there have been a variety of mechanisms proposed to explain this "warming hole", the spatial and temporal definitions of the warming hole often differ across studies, potentially obfuscating the physical drivers leading to its existence. Further, a broad consensus on the causality of the warming hole has yet to be reached. We use daily temperature data from the Global Historical Climate Network (GHCN) to conduct a thorough characterization of the spatiotemporal evolution and seasonality of regional cooling across the Eastern U.S., and define a dynamic warming hole as the region of most persistent cooling. We find that the location of the dynamic warming hole varies by season from the Midwestern U.S. during summer to the Southeastern U.S. during winter. In addition, the cool period associated with the warming hole is characterized by an abrupt decrease in maximum temperature (Tx) and a decline in minimum temperature (Tn) around 1957. While average Tn values in the warming hole recover after the decline and increase from the mid 1960's to present, Tx values for the second half of the 20th century remain below observed values from the first half of the century. To explore large-scale atmospheric drivers of the dynamic warming hole, we correlate SST teleconnection and regional atmospheric circulation indices with seasonal temperature values from 1901-1957 and 1958-2015. We show that 1957 marks a shift, where winter temperatures in the warming hole become more correlated with the Pacific Decadal Oscillation (PDO) and North Atlantic Oscillation (NAO) and less correlated with the Atlantic Multidecadal Oscillation (AMO). Summer warming hole temperatures become less correlated with the NAO post 1957 and are strongly negatively correlated with precipitation.

  19. Warm-season severe wind events in Germany

    NASA Astrophysics Data System (ADS)

    Gatzen, Christoph

    2013-04-01

    A 15-year data set of wind measurements was analyzed with regard to warm season severe wind gusts in Germany. For April to September of the years 1997 to 2011, 1035 wind measurements of 26 m/s or greater were found. These wind reports were associated with 268 wind events. In total, 252 convective wind events contributed to 837 (81%) of the wind reports, 16 non-convective synoptic-scale wind events contributed to 198 reports (19%). Severe wind events were found with synoptic situations characterized by rather strong mid-level flow and advancing mid-level troughs. Severe convective wind events were analyzed using radar images and classified with respect to the observed radar structure. The most important convective mode was squall lines that were associated with one third of all severe wind gusts, followed by groups, bow echo complexes, and bow echoes. Supercells and cells were not associated with many wind reports. The low contribution of isolated cells indicates that rather large-scale forcing by synoptic-scale features like fronts is important for German severe wind events. Bow echoes were found to be present for 58% of all wind reports. The movement speed of bow echoes indicated a large variation with a maximum speed of 33 m/s. Extreme wind events as well as events with more than 15 wind reports were found to be related to higher movement speeds. Concentrating on the most intense events, derechos seem to be very important to the warm season wind threat in Germany. Convective events with a path length of more than 400 km contributed to 36% of all warm-season wind gusts in this data set. Furthermore, eight of nine extreme gusts exceeding 40 m/s were recorded with derecho events.

  20. Seasonality of coastal upwelling trends under future warming scenarios along the southern limit of the canary upwelling system

    NASA Astrophysics Data System (ADS)

    Sousa, Magda Catarina; Alvarez, Ines; deCastro, Maite; Gomez-Gesteira, Moncho; Dias, João Miguel

    2017-04-01

    The Canary Upwelling Ecosystem (CUE) is one of the four most important upwelling sites around the world in terms of primary production, with coastal upwelling mostly a year-round phenomenon south of 30°N. Based on annual future projections, several previous studies indicated that global warming will intensify coastal upwelling in the northern region and will induce its weakening at the southernmost latitudes. However, analysis of historical data, showed that coastal upwelling depends on the length of the time series, the season, and even the database used. Thus, despite previous efforts, an overall detailed description of seasonal upwelling trends and their effects on sea surface temperature (SST) along the Canary coast over the 21st century remains unclear. To address this issue, several regional and global wind and SST climate models from CORDEX and CMIP5 projects for the period 1976-2099 were analyzed. This research provides new insights about coastal upwelling trends under future warming scenarios for the CUE, with results showing opposite patterns for upwelling index (UI) trends depending on the season. A weakening of the UI occurs from May to August all along the coast, whereas it increases from October to April. Analysis of SST trends reveals a general warming throughout the area, although the warming rate is considerably lower near the shore than at open ocean locations due to coastal upwelling effects. In addition, SST projections show higher warming rates from May to August than from October to April in response to the future decreasing trend in the UI during the summer months.

  1. Warming and elevated CO2 lead to longer growing season in temperate grassland

    USDA-ARS?s Scientific Manuscript database

    Observational data over time suggest that as climate has warmed the growing season has lengthened, although experimental warming shortens early-growing species’ life cycles. Are other plant species living longer? We found that experimental warming in a temperate, semi-arid grassland led to earlier l...

  2. Fall season atypically warm weather event leads to substantial CH4 loss in Arctic ecosystems?

    NASA Astrophysics Data System (ADS)

    Zona, Donatella; Moreaux, Virginie; Liljedahl, Anna; Losacco, Salvatore; Murphy, Patrick; Oechel, Walter

    2014-05-01

    In the last century (during 1875-2008) high-latitudes are warming at a rate of 1.360C century-1, almost 2 times faster than the Northern Hemisphere trend (Bekryaev et al., 2010). This warming has been more intense outside of the summer season, with anomalies of 1.09, 1.59, 1.730C in the fall, winter, and spring season respectively (Bekryaev et al., 2010). This substantial temperature anomalies have the potential to increase the emission of greenhouse gas (CO2 and CH4) fluxes from arctic tundra ecosystems. In particular, CH4 emissions, which are primarily controlled by temperature (in addition to water table), can steeply increase with warming. Despite the potential relevance of CH4 emissions, very few measurements have been performed outside of the growing season across the entire Arctic, due to logistic constrains. Importantly, no flux measurements achieved a temporal and spatial data coverage sufficient to estimate with confidence an annual CH4 emissions from tundra ecosystem in Alaska, and its sensitivity to warming. Fall 2013 was unusually warm in central and northern Alaska. Following a relatively warm summer with dramatically above-average rainfall, the October mean monthly temperatures was the 4th and top warmest in Barrow (1949-2013) and Ivotuk (1998-2013), respectively. As we just upgraded several eddy covariance towers to measure CO2 and CH4 fluxes year-round, the atypical weather conditions of fall 2013 represented a unique chance for testing the sensitivity of CH4 loss to these atypically warm temperatures. All our sites across a latitudinal gradient (from the northern site, Barrow, to the southern site, Ivotuk), presented substantial CH4 loss in the fall. Importantly, in two of these sites (Barrow, Ivotuk) where the fall weather was substantially warmer than the long term trend, fall CH4 emission represented between 44-63% of the June-November cumulative emission. Surprisingly, in the southernmost site (Ivotuk), when the temperature anomaly was the

  3. Warm-Season Flows in Cold-Season Ravines

    NASA Image and Video Library

    2015-05-06

    Ravines or very large gullies are actively forming on Mars during the coldest times of year, when carbon dioxide frost aids mass wasting as seen by NASA Mars Reconnaissance Orbiter. However, some of these ravines also show activity in the warmest time of year, in the form of recurring slope lineae (RSL); dark, narrow flows in some alcoves that flow part way down the channels. Few topographic changes have been seen in association with RSL, and they appear to be seeps of water that seasonally extend down slopes, then fade when inactive, and recur each warm season. Could the RSL activity carve the ravines? In some places the RSL extend to the ends of the fans and appear to match in scale, and perhaps gradually form the ravines. In other places, such as this image, the ravines are much larger than the RSL, so presently-observed RSL flow did not produce the larger landforms, but maybe the flow was greater in the past or maybe the RSL just follow the topography created by other processes. The largest ravines are on pole-facing slopes in the middle latitudes, where RSL have never been seen to form, unless the ravine creates a small equator-facing slope. http://photojournal.jpl.nasa.gov/catalog/PIA19458

  4. The forcing of monthly precipitation variability over Southwest Asia during the Boreal cold season

    USGS Publications Warehouse

    Hoell, Andrew; Shukla, Shraddhanand; Barlow, Mathew; Cannon, Forest; Kelley, Colin; Funk, Christopher C.

    2015-01-01

    Southwest Asia, deemed as the region containing the countries of Afghanistan, Iran, Iraq and Pakistan, is water scarce and receives nearly 75% of its annual rainfall during8 the boreal cold season of November-April. The forcing of Southwest Asia precipitation has been previously examined for the entire boreal cold season from the perspective of climate variability originating over the Atlantic and tropical Indo-Pacific Oceans. Here, we examine the inter-monthly differences in precipitation variability over Southwest Asia and the atmospheric conditions directly responsible in forcing monthly November-April precipitation. Seasonally averaged November-April precipitation over Southwest Asia is significantly correlated with sea surface temperature (SST) patterns consistent with Pacific Decadal Variability (PDV), the El Nino-Southern Oscillation (ENSO) and the warming trend of SST (Trend). On the contrary, the precipitation variability during individual months of November-April are unrelated and are correlated with SST signatures that include PDV, ENSO and Trend in different combinations. Despite strong inter-monthly differences in precipitation variability during November- April over Southwest Asia, similar atmospheric circulations, highlighted by a stationary equivalent barotropic Rossby wave centered over Iraq, force the monthly spatial distributions of precipitation. Tropospheric waves on the eastern side of the equivalent barotropic Rossby wave modifies the flux of moisture and advects the mean temperature gradient, resulting in temperature advection that is balanced by vertical motions over Southwest Asia. The forcing of monthly Southwest Asia precipitation by equivalent barotropic Rossby waves is different than the forcing by baroclinic Rossby waves associated with tropically-forced-only modes of climate variability.

  5. Seasonal flows on warm Martian slopes

    USGS Publications Warehouse

    McEwen, A.S.; Ojha, L.; Dundas, C.M.; Mattson, S.S.; Byrne, S.; Wray, J.J.; Cull, S.C.; Murchie, S.L.; Thomas, N.; Gulick, V.C.

    2011-01-01

    Water probably flowed across ancient Mars, but whether it ever exists as a liquid on the surface today remains debatable. Recurring slope lineae (RSL) are narrow (0.5 to 5 meters), relatively dark markings on steep (25?? to 40??) slopes; repeat images from the Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment show them to appear and incrementally grow during warm seasons and fade in cold seasons. They extend downslope from bedrock outcrops, often associated with small channels, and hundreds of them form in some rare locations. RSL appear and lengthen in the late southern spring and summer from 48??S to 32??S latitudes favoring equator-facing slopes, which are times and places with peak surface temperatures from ???250 to 300 kelvin. Liquid brines near the surface might explain this activity, but the exact mechanism and source of water are not understood.

  6. A new mechanism for warm-season precipitation response to global warming based on convection-permitting simulations

    NASA Astrophysics Data System (ADS)

    Dai, Aiguo; Rasmussen, Roy M.; Liu, Changhai; Ikeda, Kyoko; Prein, Andreas F.

    2017-08-01

    Climate models project increasing precipitation intensity but decreasing frequency as greenhouse gases increase. However, the exact mechanism for the frequency decrease remains unclear. Here we investigate this by analyzing hourly data from regional climate change simulations with 4 km grid spacing covering most of North America using the Weather Research and Forecasting model. The model was forced with present and future boundary conditions, with the latter being derived by adding the CMIP5 19-model ensemble mean changes to the ERA-interim reanalysis. The model reproduces well the observed seasonal and spatial variations in precipitation frequency and histograms, and the dry interval between rain events over the contiguous US. Results show that overall precipitation frequency indeed decreases during the warm season mainly due to fewer light-moderate precipitation (0.1 < P ≤ 2.0 mm/h) events, while heavy (2 < P ≤ 10 mm/h) to very heavy precipitation (P > 10 mm/h) events increase. Dry spells become longer and more frequent, together with a reduction in time-mean relative humidity (RH) in the lower troposphere during the warm season. The increased dry hours and decreased RH lead to a reduction in overall precipitation frequency and also for light-moderate precipitation events, while water vapor-induced increases in precipitation intensity and the positive latent heating feedback in intense storms may be responsible for the large increase in intense precipitation. The size of intense storms increases while their number decreases in the future climate, which helps explain the increase in local frequency of heavy precipitation. The results generally support a new hypothesis for future warm-season precipitation: each rainstorm removes ≥7% more moisture from the air per 1 K local warming, and surface evaporation and moisture advection take slightly longer than currently to replenish the depleted moisture before the next storm forms, leading to longer dry spells and

  7. Striking Seasonality in the Secular Warming of the Northern Continents: Structure and Mechanisms

    NASA Astrophysics Data System (ADS)

    Nigam, S.; Thomas, N. P.

    2017-12-01

    The linear trend in twentieth-century surface air temperature (SAT)—a key secular warming signal— exhibits striking seasonal variations over Northern Hemisphere continents; SAT trends are pronounced in winter and spring but notably weaker in summer and fall. The SAT trends in historical twentieth-century climate simulations informing the Intergovernmental Panel for Climate Change's Fifth Assessment show varied (and often unrealistic) strength and structure, and markedly weaker seasonal variation. The large intra-ensemble spread of winter SAT trends in some historical simulations was surprising, especially in the context of century-long linear trends, with implications for the detection of the secular warming signal. The striking seasonality of observed secular warming over northern continents warrants an explanation and the representation of related processes in climate models. Here, the seasonality of SAT trends over North America is shown to result from land surface-hydroclimate interactions and, to an extent, also from the secular change in low-level atmospheric circulation and related thermal advection. It is argued that the winter dormancy and summer vigor of the hydrologic cycle over middle- to high-latitude continents permit different responses to the additional incident radiative energy from increasing greenhouse gas concentrations. The seasonal cycle of climate, despite its monotony, provides an expanded phase space for the exposition of the dynamical and thermodynamical processes generating secular warming, and an exceptional cost-effective opportunity for benchmarking climate projection models.

  8. Seasonal flows on warm Martian slopes

    USGS Publications Warehouse

    McEwen, Alfred S.; Ojha, Lujendra; Dundas, Colin M.; Mattson, Sarah S.; Byrne, Shane; Wray, James J.; Cull, Selby C.; Murchie, Scott L.; Thomas, Nicolas; Gulick, Virginia C.

    2011-01-01

    Water probably flowed across ancient Mars, but whether it ever exists as a liquid on the surface today remains debatable. Recurring slope lineae (RSL) are narrow (0.5 to 5 meters), relatively dark markings on steep (25° to 40°) slopes; repeat images from the Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment show them to appear and incrementally grow during warm seasons and fade in cold seasons. They extend downslope from bedrock outcrops, often associated with small channels, and hundreds of them form in some rare locations. RSL appear and lengthen in the late southern spring and summer from 48°S to 32°S latitudes favoring equator-facing slopes, which are times and places with peak surface temperatures from ~250 to 300 kelvin. Liquid brines near the surface might explain this activity, but the exact mechanism and source of water are not understood.

  9. Seasonal flows on warm Martian slopes.

    PubMed

    McEwen, Alfred S; Ojha, Lujendra; Dundas, Colin M; Mattson, Sarah S; Byrne, Shane; Wray, James J; Cull, Selby C; Murchie, Scott L; Thomas, Nicolas; Gulick, Virginia C

    2011-08-05

    Water probably flowed across ancient Mars, but whether it ever exists as a liquid on the surface today remains debatable. Recurring slope lineae (RSL) are narrow (0.5 to 5 meters), relatively dark markings on steep (25° to 40°) slopes; repeat images from the Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment show them to appear and incrementally grow during warm seasons and fade in cold seasons. They extend downslope from bedrock outcrops, often associated with small channels, and hundreds of them form in some rare locations. RSL appear and lengthen in the late southern spring and summer from 48°S to 32°S latitudes favoring equator-facing slopes, which are times and places with peak surface temperatures from ~250 to 300 kelvin. Liquid brines near the surface might explain this activity, but the exact mechanism and source of water are not understood.

  10. Statistical significance of seasonal warming/cooling trends

    NASA Astrophysics Data System (ADS)

    Ludescher, Josef; Bunde, Armin; Schellnhuber, Hans Joachim

    2017-04-01

    The question whether a seasonal climate trend (e.g., the increase of summer temperatures in Antarctica in the last decades) is of anthropogenic or natural origin is of great importance for mitigation and adaption measures alike. The conventional significance analysis assumes that (i) the seasonal climate trends can be quantified by linear regression, (ii) the different seasonal records can be treated as independent records, and (iii) the persistence in each of these seasonal records can be characterized by short-term memory described by an autoregressive process of first order. Here we show that assumption ii is not valid, due to strong intraannual correlations by which different seasons are correlated. We also show that, even in the absence of correlations, for Gaussian white noise, the conventional analysis leads to a strong overestimation of the significance of the seasonal trends, because multiple testing has not been taken into account. In addition, when the data exhibit long-term memory (which is the case in most climate records), assumption iii leads to a further overestimation of the trend significance. Combining Monte Carlo simulations with the Holm-Bonferroni method, we demonstrate how to obtain reliable estimates of the significance of the seasonal climate trends in long-term correlated records. For an illustration, we apply our method to representative temperature records from West Antarctica, which is one of the fastest-warming places on Earth and belongs to the crucial tipping elements in the Earth system.

  11. Copepod community succession during warm season in Lagoon Notoro-ko, northeastern Hokkaido, Japan

    NASA Astrophysics Data System (ADS)

    Nakagawa, Yoshizumi; Ichikawa, Hideaki; Kitamura, Mitsuaki; Nishino, Yasuto; Taniguchi, Akira

    2015-06-01

    Lagoon Notoro-ko, located on the northeastern coast of Hokkaido, Japan, and connected to the Okhotsk Sea by a human-made channel, is strongly influenced by local hydrography, as water masses in the lagoon are seasonally influenced by the Soya Warm Current and the East Sakhalin Current. We here report on the succession of copepod communities during the warm season in relation to water mass exchange. Copepods were categorized into four seasonal communities (spring/early-summer, mid-summer, late-summer/fall, and early-winter) via a cluster analysis based on Bray-Curtis similarities. Spring/early-summer and early-winter communities were characterized by the temperate-boreal calanoid Pseudocalanus newmani, comprising 34.9%-77.6% of the total abundance of copepods during times of low temperature/salinity, as influenced by the prevailing East Sakhalin Current. Late-summer/fall communities were characterized by the neritic warm-water calanoid Paracalanus parvus s.l., comprising 63.9%-96.3% of the total abundance, as influenced by the Soya Warm Current. Mid-summer communities comprised approximately equal abundances of P. parvus, Eurytemora herdmani, Scolecithricella minor, and Centropages abdominalis (12.8%-28.2%); this community is transitional between those of the spring/early-summer and late-summer/fall. Copepod community succession in Lagoon Notoro-ko can be largely explained by seasonal changes in water masses.

  12. [CO2-exchange in tundra ecosystems of Vaygach Island during the unusually warm and dry vegetation season].

    PubMed

    Zamolodchikov, D G

    2015-01-01

    In summer of 2013, field studies of CO2-exchange in tundra ecosystems of Vaygach Island have been conducted using the chamber method. The models are developed that establish relationships between CO2 fluxes and key ecological factors such as temperature, photosynthetic active radiation, leaf mass of vascular plants, and depth of thawing. According to the model estimates, in 2013 vegetation season tundra ecosystems of Vaygach Island have been appearing to be a CO2 source to the atmosphere (31.9 ± 17.1 g C m(-2) season(-1)) with gross primary production equal to 136.6 ± 18.9 g C m(-2) season(-1) and ecosystem respiration of 168.5 ± ± 18.4 g C m(-2) season(-1). Emission of CO2 from the soil surface (soil respiration) has been equal, on the average, to 67.3% of the ecosystem respiration. The reason behind carbon losses by tundra ecosystems seems to be unusually warm and dry weather conditions in 2013 summer. The air temperature during summer months has been twice as high as the climatic norm for 1961-1990. Last decades, researches in the circumpolar Arctic revealed a growing trend to the carbon sink from the atmosphere to tundra ecosystems. This trend can be interrupted by unusually warm weather situations becoming more frequent and of larger scale.

  13. Establishment of warm season grasses with and without the use of compost soil amendments

    USGS Publications Warehouse

    Perry, M.C.; Osenton, P.C.; Gough, G.A.; Lohnes, E.J.R.

    2000-01-01

    Two compost materials (COMPRO and LEAFGRO) were evaluated as soil amendments to enhance wildlife habitats, while maintaining optimal floral and faunal biodiversity. Special emphasis was placed on the role of compost in the establishment and retention of native warm season grasses (Andropogon gerardi, Schizachyrium scoparium, and Sorghastrum nutans). This study was conducted at two sites that were degraded by previous military and farming operations. Sites were plowed twice in 1996 and then a one inch layer of COMPRO or LEAFGRO was applied with a modified manure spreader and disked into the soil to a depth of 3 inches. Vegetation sampling was conducted in 1996, 1997, 1998, and 1999. Initially the greatest vegetation cover occurred in plots treated with LEAFGRO. Plots treated with COMPRO had less vegetation cover than both types of controls plots (with and without warmseason grasses). The reduced plant growth in the plots treated with COMPRO may have been related to the much higher soil pH of these plots on both sites. In subsequent years, amounts of warm season grasses increased, however, in general there was more cover of warm season grasses in plots that did not receive compost than those that did receive compost. Sorghastrum nutans was more abundant on the sites than either of the other two species of warm season grasses. Invertebrate and mammal data collected for three years indicated that there was not more faunal activity in the plots treated with LEAFGRO or COMPRO compost soil amendments. Results indicate that compost amendments did not improve establishment of warm season grasses and the resultant faunal diversity or abundance.

  14. Weather Research and Forecasting Model Sensitivity Comparisons for Warm Season Convective Initiation

    NASA Technical Reports Server (NTRS)

    Watson, Leela R.; Hoeth, Brian; Blottman, Peter F.

    2007-01-01

    Mesoscale weather conditions can significantly affect the space launch and landing operations at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). During the summer months, land-sea interactions that occur across KSC and CCAFS lead to the formation of a sea breeze, which can then spawn deep convection. These convective processes often last 60 minutes or less and pose a significant challenge to the forecasters at the National Weather Service (NWS) Spaceflight Meteorology Group (SMG). The main challenge is that a "GO" forecast for thunderstorms and precipitation at the Shuttle Landing Facility is required at the 90 minute deorbit decision for End Of Mission (EOM) and at the 30 minute Return To Launch Site (RTLS) decision. Convective initiation, timing, and mode also present a forecast challenge for the NWS in Melbourne, FL (MLB). The NWS MLB issues such tactical forecast information as Terminal Aerodrome Forecasts (TAF5), Spot Forecasts for fire weather and hazardous materials incident support, and severe/hazardous weather Watches, Warnings, and Advisories. Lastly, these forecasting challenges can also affect the 45th Weather Squadron (45 WS), which provides comprehensive weather forecasts for shuttle launch, as well as ground operations, at KSC and CCAFS. The need for accurate mesoscale model forecasts to aid in their decision making is crucial. This study specifically addresses the skill of different model configurations in forecasting warm season convective initiation. Numerous factors influence the development of convection over the Florida peninsula. These factors include sea breezes, river and lake breezes, the prevailing low-level flow, and convergent flow due to convex coastlines that enhance the sea breeze. The interaction of these processes produces the warm season convective patterns seen over the Florida peninsula. However, warm season convection remains one of the most poorly forecast meteorological parameters. To determine which

  15. Nitrogen and harvest impact on warm-season grasses biomass yield

    USDA-ARS?s Scientific Manuscript database

    Perennial warm-season grasses have drawn interest as bioenergy feedstocks due to their high productivity with minimal amounts of inputs while producing multiple environmental benefits. Nitrogen (N) fertility and harvest timing are critical management practices when optimizing biomass yield of these ...

  16. Weather Research and Forecasting Model Sensitivity Comparisons for Warm Season Convective Initiation

    NASA Technical Reports Server (NTRS)

    Watson, Leela R.

    2007-01-01

    This report describes the work done by the Applied Meteorology Unit (AMU) in assessing the success of different model configurations in predicting warm season convection over East-Central Florida. The Weather Research and Forecasting Environmental Modeling System (WRF EMS) software allows users to choose among two dynamical cores - the Advanced Research WRF (ARW) and the Non-hydrostatic Mesoscale Model (NMM). There are also data assimilation analysis packages available for the initialization of the WRF model - the Local Analysis and Prediction System (LAPS) and the Advanced Regional Prediction System (ARPS) Data Analysis System (ADAS). Besides model core and initialization options, the WRF model can be run with one- or two-way nesting. Having a series of initialization options and WRF cores, as well as many options within each core, creates challenges for local forecasters, such as determining which configuration options are best to address specific forecast concerns. This project assessed three different model intializations available to determine which configuration best predicts warm season convective initiation in East-Central Florida. The project also examined the use of one- and two-way nesting in predicting warm season convection.

  17. Warm-Season Flows on Slope in Horowitz Crater Nine-Image Sequence

    NASA Image and Video Library

    2011-08-04

    This image comes from observations of Horowitz crater by the HiRISE camera onboard NASA Mars Reconnaissance Orbiter. The features that extend down the slope during warm seasons are called recurring slope lineae.

  18. The responses of microbial temperature relationships to seasonal change and winter warming in a temperate grassland.

    PubMed

    Birgander, Johanna; Olsson, Pål Axel; Rousk, Johannes

    2018-01-18

    Microorganisms dominate the decomposition of organic matter and their activities are strongly influenced by temperature. As the carbon (C) flux from soil to the atmosphere due to microbial activity is substantial, understanding temperature relationships of microbial processes is critical. It has been shown that microbial temperature relationships in soil correlate with the climate, and microorganisms in field experiments become more warm-tolerant in response to chronic warming. It is also known that microbial temperature relationships reflect the seasons in aquatic ecosystems, but to date this has not been investigated in soil. Although climate change predictions suggest that temperatures will be mostly affected during winter in temperate ecosystems, no assessments exist of the responses of microbial temperature relationships to winter warming. We investigated the responses of the temperature relationships of bacterial growth, fungal growth, and respiration in a temperate grassland to seasonal change, and to 2 years' winter warming. The warming treatments increased winter soil temperatures by 5-6°C, corresponding to 3°C warming of the mean annual temperature. Microbial temperature relationships and temperature sensitivities (Q 10 ) could be accurately established, but did not respond to winter warming or to seasonal temperature change, despite significant shifts in the microbial community structure. The lack of response to winter warming that we demonstrate, and the strong response to chronic warming treatments previously shown, together suggest that it is the peak annual soil temperature that influences the microbial temperature relationships, and that temperatures during colder seasons will have little impact. Thus, mean annual temperatures are poor predictors for microbial temperature relationships. Instead, the intensity of summer heat-spells in temperate systems is likely to shape the microbial temperature relationships that govern the soil-atmosphere C

  19. Seasonal Variability May Affect Microbial Decomposers and Leaf Decomposition More Than Warming in Streams.

    PubMed

    Duarte, Sofia; Cássio, Fernanda; Ferreira, Verónica; Canhoto, Cristina; Pascoal, Cláudia

    2016-08-01

    Ongoing climate change is expected to affect the diversity and activity of aquatic microbes, which play a key role in plant litter decomposition in forest streams. We used a before-after control-impact (BACI) design to study the effects of warming on a forest stream reach. The stream reach was divided by a longitudinal barrier, and during 1 year (ambient year) both stream halves were at ambient temperature, while in the second year (warmed year) the temperature in one stream half was increased by ca. 3 °C above ambient temperature (experimental half). Fine-mesh bags containing oak (Quercus robur L.) leaves were immersed in both stream halves for up to 60 days in spring and autumn of the ambient and warmed years. We assessed leaf-associated microbial diversity by denaturing gradient gel electrophoresis and identification of fungal conidial morphotypes and microbial activity by quantifying leaf mass loss and productivity of fungi and bacteria. In the ambient year, no differences were found in leaf decomposition rates and microbial productivities either between seasons or stream halves. In the warmed year, phosphorus concentration in the stream water, leaf decomposition rates, and productivity of bacteria were higher in spring than in autumn. They did not differ between stream halves, except for leaf decomposition, which was higher in the experimental half in spring. Fungal and bacterial communities differed between seasons in both years. Seasonal changes in stream water variables had a greater impact on the activity and diversity of microbial decomposers than a warming regime simulating a predicted global warming scenario.

  20. Characterization of water quality and suspended sediment during cold-season flows, warm-season flows, and stormflows in the Fountain and Monument Creek watersheds, Colorado, 2007–2015

    USGS Publications Warehouse

    Miller, Lisa D.; Stogner, Sr., Robert W.

    2017-09-01

    From 2007 through 2015, the U.S. Geological Survey, in cooperation with Colorado Springs City Engineering, conducted a study in the Fountain and Monument Creek watersheds, Colorado, to characterize surface-water quality and suspended-sediment conditions for three different streamflow regimes with an emphasis on characterizing water quality during storm runoff. Data collected during this study were used to evaluate the effects of stormflows and wastewater-treatment effluent discharge on Fountain and Monument Creeks in the Colorado Springs, Colorado, area. Water-quality samples were collected at 2 sites on Upper Fountain Creek, 2 sites on Monument Creek, 3 sites on Lower Fountain Creek, and 13 tributary sites during 3 flow regimes: cold-season flow (November–April), warm-season flow (May–October), and stormflow from 2007 through 2015. During 2015, additional samples were collected and analyzed for Escherichia coli (E. coli) during dry weather conditions at 41 sites, located in E. coli impaired stream reaches, to help identify source areas and scope of the impairment.Concentrations of E. coli, total arsenic, and dissolved copper, selenium, and zinc in surface-water samples were compared to Colorado in-stream standards. Stormflow concentrations of E. coli frequently exceeded the recreational use standard of 126 colonies per 100 milliliters at main-stem and tributary sites by more than an order of magnitude. Even though median E. coli concentrations in warm-season flow samples were lower than median concentrations in storm-flow samples, the water quality standard for E. coli was still exceeded at most main-stem sites and many tributary sites during warm-season flows. Six samples (three warm-season flow and three stormflow samples) collected from Upper Fountain Creek, upstream from the confluence of Monument Creek, and two stormflow samples collected from Lower Fountain Creek, downstream from the confluence with Monument Creek, exceeded the acute water

  1. Can Regional Climate Models Improve Warm Season Forecasts in the North American Monsoon Region?

    NASA Astrophysics Data System (ADS)

    Dominguez, F.; Castro, C. L.

    2009-12-01

    The goal of this work is to improve warm season forecasts in the North American Monsoon Region. To do this, we are dynamically downscaling warm season CFS (Climate Forecast System) reforecasts from 1982-2005 for the contiguous U.S. using the Weather Research and Forecasting (WRF) regional climate model. CFS is the global coupled ocean-atmosphere model used by the Climate Prediction Center (CPC), a branch of the National Center for Environmental Prediction (NCEP), to provide official U.S. seasonal climate forecasts. Recently, NCEP has produced a comprehensive long-term retrospective ensemble CFS reforecasts for the years 1980-2005. These reforecasts show that CFS model 1) has an ability to forecast tropical Pacific SSTs and large-scale teleconnection patterns, at least as evaluated for the winter season; 2) has greater skill in forecasting winter than summer climate; and 3) demonstrates an increase in skill when a greater number of ensembles members are used. The decrease in CFS skill during the warm season is due to the fact that the physical mechanisms of rainfall at this time are more related to mesoscale processes, such as the diurnal cycle of convection, low-level moisture transport, propagation and organization of convection, and surface moisture recycling. In general, these are poorly represented in global atmospheric models. Preliminary simulations for years with extreme summer climate conditions in the western and central U.S. (specifically 1988 and 1993) show that CFS-WRF simulations can provide a more realistic representation of convective rainfall processes. Thus a RCM can potentially add significant value in climate forecasting of the warm season provided the downscaling methodology incorporates the following: 1) spectral nudging to preserve the variability in the large scale circulation while still permitting the development of smaller-scale variability in the RCM; and 2) use of realistic soil moisture initial condition, in this case provided by the

  2. Seasonal exposure to drought and air warming affects soil Collembola and mites.

    PubMed

    Xu, Guo-Liang; Kuster, Thomas M; Günthardt-Goerg, Madeleine S; Dobbertin, Matthias; Li, Mai-He

    2012-01-01

    Global environmental changes affect not only the aboveground but also the belowground components of ecosystems. The effects of seasonal drought and air warming on the genus level richness of Collembola, and on the abundance and biomass of the community of Collembola and mites were studied in an acidic and a calcareous forest soil in a model oak-ecosystem experiment (the Querco experiment) at the Swiss Federal Research Institute WSL in Birmensdorf. The experiment included four climate treatments: control, drought with a 60% reduction in rainfall, air warming with a seasonal temperature increase of 1.4 °C, and air warming + drought. Soil water content was greatly reduced by drought. Soil surface temperature was slightly increased by both the air warming and the drought treatment. Soil mesofauna samples were taken at the end of the first experimental year. Drought was found to increase the abundance of the microarthropod fauna, but reduce the biomass of the community. The percentage of small mites (body length ≤ 0.20 mm) increased, but the percentage of large mites (body length >0.40 mm) decreased under drought. Air warming had only minor effects on the fauna. All climate treatments significantly reduced the richness of Collembola and the biomass of Collembola and mites in acidic soil, but not in calcareous soil. Drought appeared to have a negative impact on soil microarthropod fauna, but the effects of climate change on soil fauna may vary with the soil type.

  3. Seasonal Exposure to Drought and Air Warming Affects Soil Collembola and Mites

    PubMed Central

    Xu, Guo-Liang; Kuster, Thomas M.; Günthardt-Goerg, Madeleine S.; Dobbertin, Matthias; Li, Mai-He

    2012-01-01

    Global environmental changes affect not only the aboveground but also the belowground components of ecosystems. The effects of seasonal drought and air warming on the genus level richness of Collembola, and on the abundance and biomass of the community of Collembola and mites were studied in an acidic and a calcareous forest soil in a model oak-ecosystem experiment (the Querco experiment) at the Swiss Federal Research Institute WSL in Birmensdorf. The experiment included four climate treatments: control, drought with a 60% reduction in rainfall, air warming with a seasonal temperature increase of 1.4°C, and air warming + drought. Soil water content was greatly reduced by drought. Soil surface temperature was slightly increased by both the air warming and the drought treatment. Soil mesofauna samples were taken at the end of the first experimental year. Drought was found to increase the abundance of the microarthropod fauna, but reduce the biomass of the community. The percentage of small mites (body length 0.20 mm) increased, but the percentage of large mites (body length >0.40 mm) decreased under drought. Air warming had only minor effects on the fauna. All climate treatments significantly reduced the richness of Collembola and the biomass of Collembola and mites in acidic soil, but not in calcareous soil. Drought appeared to have a negative impact on soil microarthropod fauna, but the effects of climate change on soil fauna may vary with the soil type. PMID:22905210

  4. Seasonal responses of soil respiration to warming and nitrogen addition in a semi-arid alfalfa-pasture of the Loess Plateau, China.

    PubMed

    Fang, Chao; Ye, Jian-Sheng; Gong, Yanhong; Pei, Jiuying; Yuan, Ziqiang; Xie, Chan; Zhu, Yusi; Yu, Yueyuan

    2017-07-15

    Responses of soil respiration (R s ) to increasing nitrogen (N) deposition and warming will have far-reaching influences on global carbon (C) cycling. However, the seasonal (growing and non-growing seasons) difference of R s responses to warming and N deposition has rarely been investigated. We conducted a field manipulative experiment in a semi-arid alfalfa-pasture of northwest China to evaluate the response of R s to nitrogen addition and warming from March 2014 to March 2016. Open-top chambers were used to elevate temperature and N was enriched at a rate of 4.42g m -2 yr -1 with NH 4 NO 3 . Results showed that (1) N addition increased R s by 14% over the two-year period; and (2) warming stimulated R s by 15% in the non-growing season, while inhibited it by 5% in the growing season, which can be explained by decreased plant coverage and soil water. The main effect of N addition did not change with time, but that of warming changed with time, with the stronger inhibition observed in the dry year. When N addition and warming were combined, an antagonistic effect was observed in the growing season, whereas a synergism was observed in the non-growing season. Overall, warming and N addition did not affect the Q10 values over the two-year period, but these treatments significantly increased the Q10 values in the growing season compared with the control treatment. In comparison, combined warming and nitrogen addition significantly reduced the Q10 values compared with the single factor treatment. These results suggest that the negative indirect effect of warming-induced water stress overrides the positive direct effect of warming on R s . Our results also imply the necessity of considering the different R s responses in the growing and non-growing seasons to climate change to accurately evaluate the carbon cycle in the arid and semi-arid regions. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Chronic environmental stress enhances tolerance to seasonal gradual warming in marine mussels

    PubMed Central

    Múgica, Maria; Izagirre, Urtzi; Sokolova, Inna M.

    2017-01-01

    In global climate change scenarios, seawater warming acts in concert with multiple stress sources, which may enhance the susceptibility of marine biota to thermal stress. Here, the responsiveness to seasonal gradual warming was investigated in temperate mussels from a chronically stressed population in comparison with a healthy one. Stressed and healthy mussels were subjected to gradual temperature elevation for 8 days (1°C per day; fall: 16–24°C, winter: 12–20°C, summer: 20–28°C) and kept at elevated temperature for 3 weeks. Healthy mussels experienced thermal stress and entered the time-limited survival period in the fall, became acclimated in winter and exhibited sublethal damage in summer. In stressed mussels, thermal stress and subsequent health deterioration were elicited in the fall but no transition into the critical period of time-limited survival was observed. Stressed mussels did not become acclimated to 20°C in winter, when they experienced low-to-moderate thermal stress, and did not experience sublethal damage at 28°C in summer, showing instead signs of metabolic rate depression. Overall, although the thermal threshold was lowered in chronically stressed mussels, they exhibited enhanced tolerance to seasonal gradual warming, especially in summer. These results challenge current assumptions on the susceptibility of marine biota to the interactive effects of seawater warming and pollution. PMID:28333994

  6. On the shortening of Indian summer monsoon season in a warming scenario

    NASA Astrophysics Data System (ADS)

    Sabeerali, C. T.; Ajayamohan, R. S.

    2018-03-01

    Assessing the future projections of the length of rainy season (LRS) has paramount societal impact considering its potential to alter the seasonal mean rainfall over the Indian subcontinent. Here, we explored the projections of LRS using both historical and Representative Concentration Pathways 8.5 (RCP8.5) simulations of the Coupled Model Intercomparison Project Phase5 (CMIP5). RCP8.5 simulations project shortening of the LRS of Indian summer monsoon by altering the timing of onset and withdrawal dates. Most CMIP5 RCP8.5 model simulations indicate a faster warming rate over the western tropical Indian Ocean compared to other regions of the Indian Ocean. It is found that the pronounced western Indian Ocean warming and associated increase in convection results in warmer upper troposphere over the Indian Ocean compared to the Indian subcontinent, reducing the meridional gradient in upper tropospheric temperature (UTT) over the Asian summer monsoon (ASM) domain. The weakening of the meridional gradient in UTT induces weakening of easterly vertical wind shear over the ASM domain during first and last phase of monsoon, facilitate delayed (advanced) monsoon onset (withdrawal) dates, ensues the shortening of LRS of the Indian summer monsoon in a warming scenario.

  7. Grassland bird productivity in warm season grass fields in southwest Wisconsin

    USGS Publications Warehouse

    Byers, Carolyn M.; Ribic, Christine; Sample, David W.; Dadisman, John D.; Guttery, Michael

    2017-01-01

    Surrogate grasslands established through federal set-aside programs, such as U.S. Department of Agriculture's Conservation Reserve Program (CRP), provide important habitat for grassland birds. Warm season grass CRP fields as a group have the potential for providing a continuum of habitat structure for breeding birds, depending on how the fields are managed and their floristic composition. We studied the nesting activity of four obligate grassland bird species, Bobolink (Dolichonyx oryzivorus), Eastern Meadowlark (Sturnella magna), Grasshopper Sparrow (Ammodramus savannarum), and Henslow's Sparrow (A. henslowii), in relation to vegetative composition and fire management in warm season CRP fields in southwest Wisconsin during 2009–2011. Intraspecific variation in apparent nest density was related to the number of years since the field was burned. Apparent Grasshopper Sparrow nest density was highest in the breeding season immediately following spring burns, apparent Henslow's Sparrow nest density was highest 1 y post burn, and apparent Bobolink and Eastern Meadowlark nest densities were higher in post fire years one to three. Grasshopper Sparrow nest density was highest on sites with more diverse vegetation, specifically prairie forbs, and on sites with shorter less dense vegetation. Bobolink, Eastern Meadowlark, and Henslow's Sparrow apparent nest densities were higher on sites with deeper litter; litter was the vegetative component that was most affected by spring burns. Overall nest success was 0.487 for Bobolink (22 d nesting period), 0.478 for Eastern Meadowlark (25 d nesting period), 0.507 for Grasshopper Sparrow (22 d nesting period), and 0.151 for Henslow's Sparrow (21 d nesting period). The major nest predators were grassland-associated species: thirteen-lined ground squirrel (Ictidomys tridecemlineatus), striped skunk (Mephitis mephitis), milk snake (Lampropeltis triangulum), American badger (Taxidea taxus), and western fox snake (Elaphe vulpina). Overall

  8. From the Lab Bench: A special use for warm-season grasses

    USDA-ARS?s Scientific Manuscript database

    A column was written to discuss the uses of warm-season annual and perennial grasses in Kentucky. These grasses are typically planted in small acreages on a farm to provide grazing during the summer slump in growth of tall fescue pastures. Moving cattle from toxic endophyte-infected tall fescue pa...

  9. Responses of greenhouse gas fluxes to experimental warming in wheat season under conventional tillage and no-tillage fields.

    PubMed

    Tu, Chun; Li, Fadong

    2017-04-01

    Understanding the effects of warming on greenhouse gas (GHG, such as N 2 O, CH 4 and CO 2 ) feedbacks to climate change represents the major environmental issue. However, little information is available on how warming effects on GHG fluxes in farmland of North China Plain (NCP). An infrared warming simulation experiment was used to assess the responses of N 2 O, CH 4 and CO 2 to warming in wheat season of 2012-2014 from conventional tillage (CT) and no-tillage (NT) systems. The results showed that warming increased cumulative N 2 O emission by 7.7% in CT but decreased it by 9.7% in NT fields (p<0.05). Cumulative CH 4 uptake and CO 2 emission were increased by 28.7%-51.7% and 6.3%-15.9% in both two tillage systems, respectively (p<0.05). The stepwise regressions relationship between GHG fluxes and soil temperature and soil moisture indicated that the supply soil moisture due to irrigation and precipitation would enhance the positive warming effects on GHG fluxes in two wheat seasons. However, in 2013, the long-term drought stress due to infrared warming and less precipitation decreased N 2 O and CO 2 emission in warmed treatments. In contrast, warming during this time increased CH 4 emission from deep soil depth. Across two years wheat seasons, warming significantly decreased by 30.3% and 63.9% sustained-flux global warming potential (SGWP) of N 2 O and CH 4 expressed as CO 2 equivalent in CT and NT fields, respectively. However, increase in soil CO 2 emission indicated that future warming projection might provide positive feedback between soil C release and global warming in NCP. Copyright © 2016. Published by Elsevier B.V.

  10. Measurement effects of seasonal and monthly variability on pedometer-determined data.

    PubMed

    Kang, Minsoo; Bassett, David R; Barreira, Tiago V; Tudor-Locke, Catrine; Ainsworth, Barbara E

    2012-03-01

    The seasonal and monthly variability of pedometer-determined physical activity and its effects on accurate measurement have not been examined. The purpose of the study was to reduce measurement error in step-count data by controlling a) the length of the measurement period and b) the season or month of the year in which sampling was conducted. Twenty-three middle-aged adults were instructed to wear a Yamax SW-200 pedometer over 365 consecutive days. The step-count measurement periods of various lengths (eg, 2, 3, 4, 5, 6, 7 days, etc.) were randomly selected 10 times for each season and month. To determine accurate estimates of yearly step-count measurement, mean absolute percentage error (MAPE) and bias were calculated. The year-round average was considered as a criterion measure. A smaller MAPE and bias represent a better estimate. Differences in MAPE and bias among seasons were trivial; however, they varied among different months. The months in which seasonal changes occur presented the highest MAPE and bias. Targeting the data collection during certain months (eg, May) may reduce pedometer measurement error and provide more accurate estimates of year-round averages.

  11. Simulation and Prediction of Warm Season Drought in North America

    NASA Technical Reports Server (NTRS)

    Wang, Hailan; Chang, Yehui; Schubert, Siegfried D.; Koster, Randal D.

    2018-01-01

    This presentation presents our recent work on model simulation and prediction of warm season drought in North America. The emphasis will be on the contribution from the leading modes of subseasonal atmospheric circulation variability, which are often present in the form of stationary Rossby waves. Here we take advantage of the results from observations, reanalyses, and simulations and reforecasts performed using the NASA Goddard Earth Observing System (GEOS-5) atmospheric and coupled General Circulation Model (GCM). Our results show that stationary Rossby waves play a key role in Northern Hemisphere (NH) atmospheric circulation and surface meteorology variability on subseasonal timescales. In particular, such waves have been crucial to the development of recent short-term warm season heat waves and droughts over North America (e.g. the 1988, 1998, and 2012 summer droughts) and northern Eurasia (e.g., the 2003 summer heat wave over Europe and the 2010 summer drought and heat wave over Russia). Through an investigation of the physical processes by which these waves lead to the development of warm season drought in North America, it is further found that these waves can serve as a potential source of drought predictability. In order to properly represent their effect and exploit this source of predictability, a model needs to correctly simulate the Northern Hemisphere (NH) mean jet streams and be able to predict the sources of these waves. Given the NASA GEOS-5 AGCM deficiency in simulating the NH jet streams and tropical convection during boreal summer, an approach has been developed to artificially remove much of model mean biases, which leads to considerable improvement in model simulation and prediction of stationary Rossby waves and drought development in North America. Our study points to the need to identify key model biases that limit model simulation and prediction of regional climate extremes, and diagnose the origin of these biases so as to inform modeling

  12. Advances in DNA markers and breeding for warm and cool-season turfgrasses

    USDA-ARS?s Scientific Manuscript database

    Warm and cool-season turfgrasses are used on lawns, parks, sport fields, golf courses and along highways and have many benefits such as erosion control, soil carbon sequestration, water filtration, heat dissipation, and providing aesthetic value. Although approximately 35,850 km2 in the United State...

  13. Recent warming by latitude associated with increased length of ragweed pollen season in central North America

    PubMed Central

    Ziska, Lewis; Knowlton, Kim; Rogers, Christine; Dalan, Dan; Tierney, Nicole; Elder, Mary Ann; Filley, Warren; Shropshire, Jeanne; Ford, Linda B.; Hedberg, Curtis; Fleetwood, Pamela; Hovanky, Kim T.; Kavanaugh, Tony; Fulford, George; Vrtis, Rose F.; Patz, Jonathan A.; Portnoy, Jay; Coates, Frances; Bielory, Leonard; Frenz, David

    2011-01-01

    A fundamental aspect of climate change is the potential shifts in flowering phenology and pollen initiation associated with milder winters and warmer seasonal air temperature. Earlier floral anthesis has been suggested, in turn, to have a role in human disease by increasing time of exposure to pollen that causes allergic rhinitis and related asthma. However, earlier floral initiation does not necessarily alter the temporal duration of the pollen season, and, to date, no consistent continental trend in pollen season length has been demonstrated. Here we report that duration of the ragweed (Ambrosia spp.) pollen season has been increasing in recent decades as a function of latitude in North America. Latitudinal effects on increasing season length were associated primarily with a delay in first frost of the fall season and lengthening of the frost free period. Overall, these data indicate a significant increase in the length of the ragweed pollen season by as much as 13–27 d at latitudes above ~44°N since 1995. This is consistent with recent Intergovernmental Panel on Climate Change projections regarding enhanced warming as a function of latitude. If similar warming trends accompany long-term climate change, greater exposure times to seasonal allergens may occur with subsequent effects on public health. PMID:21368130

  14. East Asian warm season temperature variations over the past two millennia.

    PubMed

    Zhang, Huan; Werner, Johannes P; García-Bustamante, Elena; González-Rouco, Fidel; Wagner, Sebastian; Zorita, Eduardo; Fraedrich, Klaus; Jungclaus, Johann H; Ljungqvist, Fredrik Charpentier; Zhu, Xiuhua; Xoplaki, Elena; Chen, Fahu; Duan, Jianping; Ge, Quansheng; Hao, Zhixin; Ivanov, Martin; Schneider, Lea; Talento, Stefanie; Wang, Jianglin; Yang, Bao; Luterbacher, Jürg

    2018-05-16

    East Asia has experienced strong warming since the 1960s accompanied by an increased frequency of heat waves and shrinking glaciers over the Tibetan Plateau and the Tien Shan. Here, we place the recent warmth in a long-term perspective by presenting a new spatially resolved warm-season (May-September) temperature reconstruction for the period 1-2000 CE using 59 multiproxy records from a wide range of East Asian regions. Our Bayesian Hierarchical Model (BHM) based reconstructions generally agree with earlier shorter regional temperature reconstructions but are more stable due to additional temperature sensitive proxies. We find a rather warm period during the first two centuries CE, followed by a multi-century long cooling period and again a warm interval covering the 900-1200 CE period (Medieval Climate Anomaly, MCA). The interval from 1450 to 1850 CE (Little Ice Age, LIA) was characterized by cooler conditions and the last 150 years are characterized by a continuous warming until recent times. Our results also suggest that the 1990s were likely the warmest decade in at least 1200 years. The comparison between an ensemble of climate model simulations and our summer reconstructions since 850 CE shows good agreement and an important role of internal variability and external forcing on multi-decadal time-scales.

  15. Positive feedback of greenhouse gas balances to warming is determined by non-growing season emissions in an alpine meadow

    NASA Astrophysics Data System (ADS)

    Niu, S.; Wang, J.; Quan, Q.; Chen, W.; Wen, X.; Yu, G.

    2017-12-01

    Large uncertainties exist in the sources and sinks of greenhouse gases (CO2, CH4, N2O) in response to climate warming and human activity. So far, numerous previous studies have evaluated the CO2 budget, but little attention has paid to CH4 and N2O budgets and the concurrent balance of these three gases in combination, especially in the non-growing season. Here, we synthesized eddy covariance measurement with the automatic chamber measurements of CO2, CH4, and N2O exposed to three levels of temperature treatments (ambient, +1.5 °C, +2.5 °C) and two disturbance treatments (ummowing, mowing) in an alpine meadow on the Tibetan Plateau. We have found that warming caused increase in CH4 uptake and decrease in N2O emission offset little of the enhancement in CO2 emission, triggering a positive feedback to climate warming. Warming switches the ecosystem from a net sink (-17 ± 14 g CO2-eq m-2 yr-1) in the control to a net source of greenhouse gases of 94 ± 36 gCO2-eq m-2 yr-1 in the plots with +1.5 °C warming treatment, and 177 ± 6 gCO2-eq m-2 yr-1 in the plots with +2.5 °C warming treatment. The changes in the non-growing season balance, rather than those in the growing season, dominate the warming responses of annual greehouse gas balance. And this is not changed by mowing. The dominant role of responses of winter greenhouse gas balance in the positive feedback of ecosystem to climate warming highlights that greenhouse gas balance in cold season has to be considered when assessing climate-carbon cycle feedback.

  16. The effect of temperature on different Salmonella serotypes during warm seasons in a Mediterranean climate city, Adelaide, Australia.

    PubMed

    Milazzo, A; Giles, L C; Zhang, Y; Koehler, A P; Hiller, J E; Bi, P

    2016-04-01

    Changing trends in foodborne disease are influenced by many factors, including temperature. Globally and in Australia, warmer ambient temperatures are projected to rise if climate change continues. Salmonella spp. are a temperature-sensitive pathogen and rising temperature can have a substantial effect on disease burden affecting human health. We examined the relationship between temperature and Salmonella spp. and serotype notifications in Adelaide, Australia. Time-series Poisson regression models were fit to estimate the effect of temperature during warmer months on Salmonella spp. and serotype cases notified from 1990 to 2012. Long-term trends, seasonality, autocorrelation and lagged effects were included in the statistical models. Daily Salmonella spp. counts increased by 1·3% [incidence rate ratio (IRR) 1·013, 95% confidence interval (CI) 1·008-1·019] per 1 °C rise in temperature in the warm season with greater increases observed in specific serotype and phage-type cases ranging from 3·4% (IRR 1·034, 95% CI 1·008-1·061) to 4·4% (IRR 1·044, 95% CI 1·024-1·064). We observed increased cases of S. Typhimurium PT9 and S. Typhimurium PT108 notifications above a threshold of 39 °C. This study has identified the impact of warm season temperature on different Salmonella spp. strains and confirms higher temperature has a greater effect on phage-type notifications. The findings will contribute targeted information for public health policy interventions, including food safety programmes during warmer weather.

  17. Observed decreases in the Canadian outdoor skating season due to recent winter warming

    NASA Astrophysics Data System (ADS)

    Damyanov, Nikolay N.; Damon Matthews, H.; Mysak, Lawrence A.

    2012-03-01

    Global warming has the potential to negatively affect one of Canada’s primary sources of winter recreation: hockey and ice skating on outdoor rinks. Observed changes in winter temperatures in Canada suggest changes in the meteorological conditions required to support the creation and maintenance of outdoor skating rinks; while there have been observed increases in the ice-free period of several natural water bodies, there has been no study of potential trends in the duration of the season supporting the construction of outdoor skating rinks. Here we show that the outdoor skating season (OSS) in Canada has significantly shortened in many regions of the country as a result of changing climate conditions. We first established a meteorological criterion for the beginning, and a proxy for the length of the OSS. We extracted this information from daily maximum temperature observations from 1951 to 2005, and tested it for significant changes over time due to global warming as well as due to changes in patterns of large-scale natural climate variability. We found that many locations have seen a statistically significant decrease in the OSS length, particularly in Southwest and Central Canada. This suggests that future global warming has the potential to significantly compromise the viability of outdoor skating in Canada.

  18. Annual warm-season grasses vary for forage yield, quality, and competitiveness with weeds

    USDA-ARS?s Scientific Manuscript database

    Warm-season annual grasses may be suitable as herbicide-free forage crops. A two-year field study was conducted to determine whether tillage system and nitrogen (N) fertilizer application method influenced crop and weed biomass, water use, water use efficiency (WUE), and forage quality of three war...

  19. Probability of occurrence of monthly and seasonal winter precipitation over Northwest India based on antecedent-monthly precipitation

    NASA Astrophysics Data System (ADS)

    Nageswararao, M. M.; Mohanty, U. C.; Dimri, A. P.; Osuri, Krishna K.

    2018-05-01

    Winter (December, January, and February (DJF)) precipitation over northwest India (NWI) is mainly associated with the eastward moving mid-latitude synoptic systems, western disturbances (WDs), embedded within the subtropical westerly jet (SWJ), and is crucial for Rabi (DJF) crops. In this study, the role of winter precipitation at seasonal and monthly scale over NWI and its nine meteorological subdivisions has been analyzed. High-resolution (0.25° × 0.25°) gridded precipitation data set of India Meteorological Department (IMD) for the period of 1901-2013 is used. Results indicated that the seasonal precipitation over NWI is below (above) the long-term mean in most of the years, when precipitation in any of the month (December/January/February) is in deficit (excess). The contribution of December precipitation (15-20%) to the seasonal (DJF) precipitation is lesser than January (35-40%) and February (35-50%) over all the subdivisions. December (0.60), January (0.57), and February (0.69) precipitation is in-phase (correlation) with the corresponding winter season precipitation. However, January precipitation is not in-phase with the corresponding December (0.083) and February (-0.03) precipitation, while December is in-phase with the February (0.21). When monthly precipitation (December or January or December-January or February) at subdivision level over NWI is excess (deficit); then, the probability of occurrence of seasonal excess (deficit) precipitation is high (almost nil). When antecedent-monthly precipitation is a deficit or excess, the probability of monthly (January or February or January + February) precipitation to be a normal category is >60% over all the subdivisions. This study concludes that the December precipitation is a good indicator to estimate the performance of January, February, January-February, and the seasonal (DJF) precipitation.

  20. Assessing Climate Change in Early Warm Season and Impacts on Wildfire Potential in the Southwestern United States

    NASA Astrophysics Data System (ADS)

    Kafatos, M.; Kim, S. H.; Kim, J.; Nghiem, S. V.; Fujioka, F.; Myoung, B.

    2016-12-01

    Wildfires are an important concern in the Southwestern United States (SWUS) where the prevalent semi-arid to arid climate, vegetation types and hot and dry warm seasons challenge strategic fire management. Although they are part of the natural cycle related to the region's climate, significant growth of urban areas and expansion of the wildland-urban interface, have made wildfires a serious high-risk hazard. Previous studies also showed that the SWUS region is prone to frequent droughts due to large variations in wet season rainfall and has suffered from a number of severe wildfires in the recent decades. Despite the increasing trend in large wildfires, future wildfire risk assessment studies at regional scales for proactive adaptations are lacking. Our previous study revealed strong correlations between the North Atlantic Oscillation (NAO) and temperatures during March-June in SWUS. The abnormally warm and dry conditions in an NAO-positive spring, combined with reduced winter precipitation, can cause an early start of a fire season and extend it for several seasons, from late spring to fall. A strong interannual variation of the Keetch-Byram Drought Index (KBDI) during the early warm season was also found in the 35 year period 1979 - 2013 of the North American Regional Reanalysis (NARR) dataset. Thus, it is crucial to investigate the climate change impact that early warm season temperatures have on future wildfire danger potential. Our study reported here examines fine-resolution fire-weather variables for 2041-2070 projected in the North American Regional Climate Change Assessment Program (NARCCAP). The high-resolution climate data were obtained from multiple regional climate models (RCM) driven by multiple climate scenarios projected from multiple global climate models (GCMs) in conjunction with multiple greenhouse gas concentration pathways. The local wildfire potential in future climate is investigated using both the Keetch-Byram Drought Index (KBDI) and the

  1. Magnitude and pattern of Arctic warming governed by the seasonality of radiative forcing.

    PubMed

    Bintanja, R; Krikken, F

    2016-12-02

    Observed and projected climate warming is strongest in the Arctic regions, peaking in autumn/winter. Attempts to explain this feature have focused primarily on identifying the associated climate feedbacks, particularly the ice-albedo and lapse-rate feedbacks. Here we use a state-of-the-art global climate model in idealized seasonal forcing simulations to show that Arctic warming (especially in winter) and sea ice decline are particularly sensitive to radiative forcing in spring, during which the energy is effectively 'absorbed' by the ocean (through sea ice melt and ocean warming, amplified by the ice-albedo feedback) and consequently released to the lower atmosphere in autumn and winter, mainly along the sea ice periphery. In contrast, winter radiative forcing causes a more uniform response centered over the Arctic Ocean. This finding suggests that intermodel differences in simulated Arctic (winter) warming can to a considerable degree be attributed to model uncertainties in Arctic radiative fluxes, which peak in summer.

  2. Seasonally different response of photosynthetic activity to daytime and night-time warming in the Northern Hemisphere

    DOE PAGES

    Tan, Jianguang; Piao, Shilong; Chen, Anping; ...

    2014-08-27

    Over the last century the Northern Hemisphere has experienced rapid climate warming, but this warming has not been evenly distributed seasonally, as well as diurnally. The implications of such seasonal and diurnal heterogeneous warming on regional and global vegetation photosynthetic activity, however, are still poorly understood. Here, we investigated for different seasons how photosynthetic activity of vegetation correlates with changes in seasonal daytime and night-time temperature across the Northern Hemisphere (>30°N), using Normalized Difference Vegetation Index (NDVI) data from 1982 to 2011 obtained from the Advanced Very High Resolution Radiometer (AVHRR). Our analysis revealed some striking seasonal differences in themore » response of NDVI to changes in day- versus night-time temperatures. For instance, while higher daytime temperature (T max) is generally associated with higher NDVI values across the boreal zone, the area exhibiting a statistically significant positive correlation between T max and NDVI is much larger in spring (41% of area in boreal zone – total area 12.6 × 10 6 km 2) than in summer and autumn (14% and 9%, respectively). In contrast to the predominantly positive response of boreal ecosystems to changes in T max, increases in T max tended to negatively influence vegetation growth in temperate dry regions, particularly during summer. Changes in night-time temperature (T min) correlated negatively with autumnal NDVI in most of the Northern Hemisphere, but had a positive effect on spring and summer NDVI in most temperate regions (e.g., Central North America and Central Asia). Such divergent covariance between the photosynthetic activity of Northern Hemispheric vegetation and day- and night-time temperature changes among different seasons and climate zones suggests a changing dominance of ecophysiological processes across time and space. Lastly, understanding the seasonally different responses of vegetation photosynthetic activity to

  3. Mercury concentration in phytoplankton in response to warming of an autumn - winter season.

    PubMed

    Bełdowska, Magdalena; Kobos, Justyna

    2016-08-01

    Among other climate changes in the southern Baltic, there is a tendency towards warming, especially in autumn-winter. As a result, the ice cover on the coastal zone often fails to occur. This is conducive to the thriving of phytoplankton, in which metals, including mercury, can be accumulated. The dry deposition of atmospheric Hg during heating seasons is more intense than in non-heating seasons, owing to the combustion of fossil fuels for heating purposes. This has resulted in studies into the role of phytoplankton in the introduction of Hg into the first link of trophic chain, as a function of autumn and winter warming in the coastal zone of the lagoon. The studies were conducted at two stations in the coastal zone of the southern Baltic, in the Puck Lagoon, between December 2011 and May 2013. The obtained results show that, in the estuary region, the lack of ice cover can lead to a 30% increase and during an "extremely warm" autumn and winter an increase of up to three-fold in the mean annual Hg pool in phytoplankton (mass of Hg in phytoplankton per liter of seawater). The Hg content in phytoplankton was higher when Mesodinium rubrum was prevalent in the biomass, while the proportion of dinoflagellates was small. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Evaluation of Multi-Model Ensemble System for Seasonal and Monthly Prediction

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Van den Dool, H. M.

    2013-12-01

    Since August 2011, the realtime seasonal forecasts of U.S. National Multi-Model Ensemble (NMME) have been made on 8th of each month by NCEP Climate Prediction Center (CPC). During the first year, the participating models were NCEP/CFSv1&2, GFDL/CM2.2, NCAR/U.Miami/COLA/CCSM3, NASA/GEOS5, IRI/ ECHAM-a & ECHAM-f for the realtime NMME forecast. The Canadian Meteorological Center CanCM3 and CM4 replaced the CFSv1 and IRI's models in the second year. The NMME team at CPC collects three variables, including precipitation, 2-meter temperature and sea surface temperature from each modeling center on a 1x1 global grid, removes systematic errors, makes the grand ensemble mean with equal weight for each model and constructs a probability forecast with equal weight for each member. The team then provides the NMME forecast to the operational CPC forecaster responsible for the seasonal and monthly outlook each month. Verification of the seasonal and monthly prediction from NMME is conducted by calculating the anomaly correlation (AC) from the 30-year hindcasts (1982-2011) of individual model and NMME ensemble. The motivation of this study is to provide skill benchmarks for future improvements of the NMME seasonal and monthly prediction system. The experimental (Phase I) stage of the project already supplies routine guidance to users of the NMME forecasts.

  5. Incorporating residual temperature and specific humidity in predicting weather-dependent warm-season electricity consumption

    NASA Astrophysics Data System (ADS)

    Guan, Huade; Beecham, Simon; Xu, Hanqiu; Ingleton, Greg

    2017-02-01

    Climate warming and increasing variability challenges the electricity supply in warm seasons. A good quantitative representation of the relationship between warm-season electricity consumption and weather condition provides necessary information for long-term electricity planning and short-term electricity management. In this study, an extended version of cooling degree days (ECDD) is proposed for better characterisation of this relationship. The ECDD includes temperature, residual temperature and specific humidity effects. The residual temperature is introduced for the first time to reflect the building thermal inertia effect on electricity consumption. The study is based on the electricity consumption data of four multiple-street city blocks and three office buildings. It is found that the residual temperature effect is about 20% of the current-day temperature effect at the block scale, and increases with a large variation at the building scale. Investigation of this residual temperature effect provides insight to the influence of building designs and structures on electricity consumption. The specific humidity effect appears to be more important at the building scale than at the block scale. A building with high energy performance does not necessarily have low specific humidity dependence. The new ECDD better reflects the weather dependence of electricity consumption than the conventional CDD method.

  6. Seasonal variations in methane fluxes in response to summer warming and leaf litter addition in a subarctic heath ecosystem

    NASA Astrophysics Data System (ADS)

    Pedersen, Emily Pickering; Elberling, Bo; Michelsen, Anders

    2017-08-01

    Methane (CH4) is a powerful greenhouse gas controlled by both biotic and abiotic processes. Few studies have investigated CH4 fluxes in subarctic heath ecosystems, and climate change-induced shifts in CH4 flux and the overall carbon budget are therefore largely unknown. Hence, there is an urgent need for long-term in situ experiments allowing for the study of ecosystem processes over time scales relevant to environmental change. Here we present in situ CH4 and CO2 flux measurements from a wet heath ecosystem in northern Sweden subjected to 16 years of manipulations, including summer warming with open-top chambers, birch leaf litter addition, and the combination thereof. Throughout the snow-free season, the ecosystem was a net sink of CH4 and CO2 (CH4 -0.27 mg C m-2 d-1; net ecosystem exchange -1827 mg C m-2 d-1), with highest CH4 uptake rates (-0.70 mg C m-2 d-1) during fall. Warming enhanced net CO2 flux, while net CH4 flux was governed by soil moisture. Litter addition and the combination with warming significantly increased CH4 uptake rates, explained by a pronounced soil drying effect of up to 32% relative to ambient conditions. Both warming and litter addition also increased the seasonal average concentration of dissolved organic carbon in the soil. The site was a carbon sink with a net uptake of 60 g C m-2 over the snow-free season. However, warming reduced net carbon uptake by 77%, suggesting that this ecosystem type might shift from snow-free season sink to source with increasing summer temperatures.

  7. Consistent leaf respiratory response to experimental warming of three North American deciduous trees: a comparison across seasons, years, habitats and sites.

    PubMed

    Wei, Xiaorong; Sendall, Kerrie M; Stefanski, Artur; Zhao, Changming; Hou, Jihua; Rich, Roy L; Montgomery, Rebecca A; Reich, Peter B

    2017-03-01

    Most vascular plants acclimate respiration to changes in ambient temperature, but explicit tests of these responses in field settings are rare, and how acclimation responses vary in space and time is relatively unstudied, hindering our ability to predict respiratory release of carbon under future climatic conditions. We measured temperature response curves of leaf respiration for three deciduous tree species from 2009 to 2012 in a field warming experiment (+3.4 °C above ambient) in both open and understory conditions at two sites in the southern boreal forest in Minnesota, USA. We analyzed the effects of warming on leaf respiration, and how the effects varied among species, times of season (early, middle and late parts of the growing season), sites, habitats (understory, open) and years. We hypothesized that the respiration exponent (Q10) of the short-term temperature response curve and the degree of acclimation would be smaller under conditions where plants were more likely to be substrate limited, such as in the understory or the margins of the growing season. However, in contrast to these predictions, stable Q10 and strong respiratory acclimation were consistently observed. For each species, the Q10 did not vary with experimental warming, nor was its response to warming influenced by time of season, year, site or habitat. Strong leaf respiratory acclimation to warming occurred in each species and was consistent across most sources of variation. Most of the leaf traits studied were not affected by warming, while the Q10-leaf nitrogen and R25-soluble carbohydrate relationships were observed, and shifted with warming, implying that acclimation may be associated with the adjustment in respiratory capacity and its relation to leaf nitrogen and soluble carbohydrate content. Consistent Q10 and acclimation across habitats, sites, times of season and years suggest that modeling of temperature acclimation may be possible with relatively simple functions. © The Author

  8. Establishment of warm-season native grasses and forbs on drastically disturbed lands

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Miller, S.

    Establishment of warm-season native grasses and forbs (WSNGs) has been viewed by landowners, agronomists, natural resource managers and reclamation specialists as being too expensive and difficult, especially for reclamation, which requires early stand closure and erosion control. Natural resource managers have learned a great deal about establishing WSNGs since the implementation of the 1985 Farm Bill`s Conservation Reserve Program (CRP). Reclamation specialists must begin to use this information to improve reclamation success. Quality control of seed equipment and planting methods has been proven to be the crucial first step in successful establishment. Seedling germination, growth and development of WSNGs aremore » different from that of introduced cool-season grasses and legumes. Specialized seed drills and spring planting periods are essential. Because shoot growth lags far behind root growth the first two seasons, WSNGs often are rejected for reclamation use. Usually, the rejection is based on preconceived notions that bare ground will erode and on reclamation specialists` desire for a closed, uniform, grassy lawn. WSNG`s extensive root systems inhibit rill and gully erosion by the fall of the first season. Planting a weakly competitive, short-lived nurse crop such as perennial ryegrass (Lolium perenne) at low rates with the WSNG mixture can reduce first-season sheet and rill erosion problems and give an appearance of a closed stand. Benefits of WSNGs in soil building and their acid-tolerance make them ideal species for reclamation of drastically disturbed lands. WSNGs and forbs enhance wildlife habitat and promote natural succession and the invasion of the reclamation site by other native species, particularly hardwood trees, increasing diversity and integrating the site into the local ecosystem. This is perhaps their most important attribute. Most alien grasses and legumes inhibit natural succession, slowing the development of a stable mine soil ecosystem

  9. Disruption of the European climate seasonal clock in a warming world

    NASA Astrophysics Data System (ADS)

    Cattiaux, J.; Cassou, C.

    2015-12-01

    Strength and inland penetration of the oceanic westerly flow over Europe control a large part of the temperature variability over most of the continent. Reduced westerlies, linked to high-pressure anomalies over Scandinavia, induce cold conditions in winter and warm conditions in summer. Here we propose to define the onset of these two seasons as the calendar day where the daily circulation/temperature relationship over Western Europe switches sign. According to this meteorologically-based metrics assessed from several observational datasets, we provide robust evidence for an earlier summer onset by ~10 days between the 1960s and 2000s. Results from model ensemble simulations dedicated to detection-attribution show that this calendar advance is incompatible with the sole internal climate variability and can be attributed to anthropogenic forcings. Late winter snow disappearance over Eastern Europe affects cold air intrusion to the West when easterlies blow, and is mainly responsible for the observed present-day and near-future summer advance. Our findings agree with phenological-based trends (earlier spring events) reported for many living species over Europe, for which they provide a novel dynamical interpretation beyond the traditionally evoked global warming effect. Based on business-as-usual scenario, a seasonal shift of ~25 days is expected by 2100 for summer onset, while no clear signal arises for winter onset.

  10. Gas exchange and water relations responses of spring wheat to full-season infrared warming

    USDA-ARS?s Scientific Manuscript database

    Gas exchange and water relations responses to full-season in situ infrared (IR) warming were evaluated for hard red spring wheat (Triticum aestivum L. cv. Yecora Rojo) grown in an open field in a semi-arid desert region of the Southwest USA. A Temperature Free-Air Controlled Enhancement (T-FACE) ap...

  11. Gas Exchange and Water Relations Responses of Spring Wheat to Full-Season Infrared Warming

    USDA-ARS?s Scientific Manuscript database

    Gas exchange and water relations were evaluated under full-season in situ infrared (IR) warming for hard red spring wheat (Triticum aestivum L. cv. Yecora Rojo) grown in an open field in a semiarid desert region of the southwest USA. A temperature free-air controlled enhancement (T-FACE) apparatus u...

  12. A spurious warming trend in the NMME equatorial Pacific SST hindcasts

    NASA Astrophysics Data System (ADS)

    Shin, Chul-Su; Huang, Bohua

    2017-06-01

    Using seasonal hindcasts of six different models participating in the North American Multimodel Ensemble project, the trend of the predicted sea surface temperature (SST) in the tropical Pacific for 1982-2014 at each lead month and its temporal evolution with respect to the lead month are investigated for all individual models. Since the coupled models are initialized with the observed ocean, atmosphere, land states from observation-based reanalysis, some of them using their own data assimilation process, one would expect that the observed SST trend is reasonably well captured in their seasonal predictions. However, although the observed SST features a weak-cooling trend for the 33-year period with La Niña-like spatial pattern in the tropical central-eastern Pacific all year round, it is demonstrated that all models having a time-dependent realistic concentration of greenhouse gases (GHG) display a warming trend in the equatorial Pacific that amplifies as the lead-time increases. In addition, these models' behaviors are nearly independent of the starting month of the hindcasts although the growth rates of the trend vary with the lead month. This key characteristic of the forecasted SST trend in the equatorial Pacific is also identified in the NCAR CCSM3 hindcasts that have the GHG concentration for a fixed year. This suggests that a global warming forcing may not play a significant role in generating the spurious warming trend of the coupled models' SST hindcasts in the tropical Pacific. This model SST trend in the tropical central-eastern Pacific, which is opposite to the observed one, causes a developing El Niño-like warming bias in the forecasted SST with its peak in boreal winter. Its implications for seasonal prediction are discussed.

  13. Impact of Variable SST on Simulated Warm Season Precipitation

    NASA Astrophysics Data System (ADS)

    Saleeby, S. M.; Cotton, W. R.

    2007-05-01

    The Colorado State University - Regional Atmospheric Modeling System (CSU-RAMS) is being used to examine the variability in monsoon-related warm season precipitation over Mexico and the United States due to variability in SST. Given recent improvements and increased resolution in satellite derived SSTs it is pertinent to examine the sensitivity of the RAMS model to the variety of SST data sources that are available. In particular, we are examining this dependence across continental scales over the full warm season, as well as across the regional scale centered around the Gulf of California on time scales of individual surge events. In this study we performed an ensemble of simulations that include the 2002, 2003, and 2004 warm seasons with use of the Climatology, Reynold's, AVHRR, and MODIS SSTs. From the seasonal 90-day simulations with 30km grid spacing, it was found that variations in surface latent heat flux are directly linked to differences in SST. Regions with cooler (warmer) SST have decreased (increased) moisture flux from the ocean which is in proportion to the magnitude of the SST difference. Over the eastern Pacific, differences in low-level horizontal moisture flux show a general trend toward reduced fluxes over cooler waters and very little inland impact. Over the Gulf of Mexico, however, there is substantial variability for each dataset comparison, despite having only limited variability among the SST data. Causes of this unexpected variability are not straight-forward. Precipitation impacts are greatest near the southern coast of Mexico and along the Sierra Madres. Precipitation variability over the CONUS is rather chaotic and is limited to areas impacted by the Gulf of Mexico or monsoon convection. Another unexpected outcome is the lack of variability in areas near the northern Gulf of California where SST and latent heat flux variability is a maximum. From the 7-day surge period simulations at 7km grid spacing, we found that SST differences on the

  14. The Contribution of Mesoscale Convective Weather Systems to the Warm-Season Precipitation in the United States.

    NASA Astrophysics Data System (ADS)

    Fritsch, J. M.; Kane, R. J.; Chelius, C. R.

    1986-10-01

    The contribution of precipitation from mesoscale convective weather systems to the warm-season (April-September) rainfall in the United States is evaluated. Both Mesoscale Convective Complexes (MCC's) and other large, long-lived mesoscale convective systems that do not quite meet Maddox's criteria for being termed an MCC are included in the evaluation. The distribution and geographical limits of the precipitation from the convective weather systems are constructed for the warm seasons of 1982, a `normal' year, and 1983, a drought year. Precipitation characteristics of the systems are compared for the 2 years to determine how large-scale drought patterns affect their precipitation production.The frequency, precipitation characteristics and hydrologic ramifications of multiple occurrences, or series, of convective weather systems are presented and discussed. The temporal and spatial characteristics of the accumulated precipitation from a series of convective complexes is investigated and compared to that of Hurricane Alicia.It is found that mesoscale convective weather systems account for approximately 30% to 70% of the warm-season (April-September) precipitation over much of the region between the Rocky Mountains and the Mississippi River. During the June through August period, their contribution is even larger. Moreover, series of convective weather systems are very likely the most prolific precipitation producer in the United States, rivaling and even exceeding that of hurricanes.Changes in the large-scale circulation patterns affected the seasonal precipitation from mesoscale convective weather systems by altering the precipitation characteristics of individual systems. In particular, for the drought period of 1983, the frequency of the convective systems remained nearly the same as in the `normal' year (1982); however, the average precipitation area and the average volumetric production significantly decreased. Nevertheless, the rainfall that was produced by

  15. An Update to the Warm-Season Convective Wind Climatology of KSC/CCAFS

    NASA Technical Reports Server (NTRS)

    Lupo, Kevin

    2012-01-01

    Total of 1100 convective events in the 17-year warm-season climatology at KSC/CCAFS. July and August typically are the peak of convective events, May being the minimum. Warning and non-warning level convective winds are more likely to occur in the late afternoon (1900-2000Z). Southwesterly flow regimes and wind directions produce the strongest winds. Storms moving from southwesterly direction tend to produce more warning level winds than those moving from the northerly and easterly directions.

  16. Greater absolute rates of N2O production and consumption with soil warming dwarf variations in denitrification enzyme temperature sensitivities across seasons

    NASA Astrophysics Data System (ADS)

    Tiemann, L. K.; Billings, S. A.

    2010-12-01

    denitrification (i.e. consumption of gross N2O production into N2) to a greater degree, and permit release of a relatively smaller proportion of the nitrate they consumed as N2O; b) the suite of enzymes responsible for N2O production and the one enzyme responsible for its consumption exhibit differential temperature sensitivities in their production and expression during winter months, but the sensitivity of these processes converges during warmer seasons; c) in spite of the smaller proportion of NO3- released as N2O with warming, warming’s positive influence on the amount of NO3- transformed by denitrifying organisms resulted in far greater absolute quantities of N2O released with incubation and seasonal warming. Continuing work explores the influence that temperature may exert on the relative abundances of denitrifying populations and their gene expression, and links these microbial characteristics to denitrification processes with warming. These data signify the importance of understanding enzyme kinetics in concert with microbial adaptation and acclimation as a factor governing the net fluxes of N2O from soil vs. its transformation into N2 with warming.

  17. Intake, digestibility, and passage rate of three warm-season grass hays consumed by beef steers

    USDA-ARS?s Scientific Manuscript database

    Florida-44 bermudagrass [Cynodon dactylon (L.) Pers.] is a fine-stemmed forage selected from a Tifton-44 field near Brooksville, FL that had drifted from the original and is highly desired for horses. The objective here was to assess quality of warm-season grass hays at different maturities in stall...

  18. Simulated versus observed patterns of warming over the extratropical Northern Hemisphere continents during the cold season

    PubMed Central

    Wallace, John M.; Fu, Qiang; Smoliak, Brian V.; Lin, Pu; Johanson, Celeste M.

    2012-01-01

    A suite of the historical simulations run with the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) models forced by greenhouse gases, aerosols, stratospheric ozone depletion, and volcanic eruptions and a second suite of simulations forced by increasing CO2 concentrations alone are compared with observations for the reference interval 1965–2000. Surface air temperature trends are disaggregated by boreal cold (November-April) versus warm (May-October) seasons and by high latitude northern (N: 40°–90 °N) versus southern (S: 60 °S–40 °N) domains. A dynamical adjustment is applied to remove the component of the cold-season surface air temperature trends (over land areas poleward of 40 °N) that are attributable to changing atmospheric circulation patterns. The model simulations do not simulate the full extent of the wintertime warming over the high-latitude Northern Hemisphere continents during the later 20th century, much of which was dynamically induced. Expressed as fractions of the concurrent trend in global-mean sea surface temperature, the relative magnitude of the dynamically induced wintertime warming over domain N in the observations, the simulations with multiple forcings, and the runs forced by the buildup of greenhouse gases only is 7∶2∶1, and roughly comparable to the relative magnitude of the concurrent sea-level pressure trends. These results support the notion that the enhanced wintertime warming over high northern latitudes from 1965 to 2000 was mainly a reflection of unforced variability of the coupled climate system. Some of the simulations exhibit an enhancement of the warming along the Arctic coast, suggestive of exaggerated feedbacks. PMID:22847408

  19. Attributing Contributions of Climate Feedbacks to the Seasonal Cycle of Surface Warming due to CO2 Increase

    NASA Astrophysics Data System (ADS)

    Sejas, S.; Cai, M.

    2012-12-01

    Surfing warming due to CO2 doubling is a robust feature of coupled general circulation models (GCM), as noted in the IPCC AR4 assessment report. In this study, the contributions of different climate feedbacks to the magnitude, spatial distribution, and seasonality of the surface warming is examined using data from NCAR's CCSM4. In particular, a focus is placed on polar regions to see which feedbacks play a role in polar amplification and its seasonal pattern. A new climate feedback analysis method is used to isolate the surface warming or cooling contributions of both radiative and non-radiative (dynamical) climate feedbacks to the total (actual) surface temperature change given by the CCSM4. These contributions (or partial surface temperature changes) are additive and their total is approximately equal to the actual surface temperature change. What is found is that the effects of CO2 doubling alone warms the surface throughout with a maximum in polar regions, which indicates the CO2 forcing alone has a degree of polar warming amplification. Water vapor feedback is a positive feedback throughout but is most responsible for the surface warming found in the tropics. Polar warming amplification is found to be strongest away from summer (especially in NH), which is primarily caused by a positive feedback due to cloud feedbacks but with the surface temperature change due to the CO2 forcing alone and the ocean dynamics and storage feedback also playing an important role. Contrary to popular belief, surface albedo feedback (SAF) does not account for much of the polar amplification. SAF tries to amplify polar warming, but in summer. No major polar amplification is seen in summer for the actual surface temperature, so SAF is not the feedback responsible for polar amplification. This is actually a consequence of the ocean dynamics and storage feedback, which negates the effects of SAF to a large degree.

  20. Global warming related transient albedo feedback in the Arctic and its relation to the seasonality of sea ice

    NASA Astrophysics Data System (ADS)

    Andry, Olivier; Bintanja, Richard; Hazeleger, Wilco

    2015-04-01

    The Arctic is warming two to three times faster than the global average. Arctic sea ice cover is very sensitive to this warming and has reached historic minima in late summer in recent years (i.e. 2007, 2012). Considering that the Arctic Ocean is mainly ice-covered and that the albedo of sea ice is very high compared to that of open water, the change in sea ice cover is very likely to have a strong impact on the local surface albedo feedback. Here we quantify the temporal changes in surface albedo feedback in response to global warming. Usually feedbacks are evaluated as being representative and constant for long time periods, but we show here that the strength of climate feedbacks in fact varies strongly with time. For instance, time series of the amplitude of the surface albedo feedback, derived from future climate simulations (CIMP5, RCP8.5 up to year 2300) using a kernel method, peaks around the year 2100. This maximum is likely caused by an increased seasonality in sea-ice cover that is inherently associated with sea ice retreat. We demonstrate that the Arctic average surface albedo has a strong seasonal signature with a maximum in spring and a minimum in late summer/autumn. In winter when incoming solar radiation is minimal the surface albedo doesn't have an important effect on the energy balance of the climate system. The annual mean surface albedo is thus determined by the seasonality of both downwelling shortwave radiation and sea ice cover. As sea ice cover reduces the seasonal signature is modified, the transient part from maximum sea ice cover to its minimum is shortened and sharpened. The sea ice cover is reduced when downwelling shortwave radiation is maximum and thus the annual surface albedo is drastically smaller. Consequently the change in annual surface albedo with time will become larger and so will the surface albedo feedback. We conclude that a stronger seasonality in sea ice leads to a stronger surface albedo feedback, which accelerates

  1. Long-term effects of warming and ocean acidification are modified by seasonal variation in species responses and environmental conditions

    PubMed Central

    Godbold, Jasmin A.; Solan, Martin

    2013-01-01

    Warming of sea surface temperatures and alteration of ocean chemistry associated with anthropogenic increases in atmospheric carbon dioxide will have profound consequences for a broad range of species, but the potential for seasonal variation to modify species and ecosystem responses to these stressors has received little attention. Here, using the longest experiment to date (542 days), we investigate how the interactive effects of warming and ocean acidification affect the growth, behaviour and associated levels of ecosystem functioning (nutrient release) for a functionally important non-calcifying intertidal polychaete (Alitta virens) under seasonally changing conditions. We find that the effects of warming, ocean acidification and their interactions are not detectable in the short term, but manifest over time through changes in growth, bioturbation and bioirrigation behaviour that, in turn, affect nutrient generation. These changes are intimately linked to species responses to seasonal variations in environmental conditions (temperature and photoperiod) that, depending upon timing, can either exacerbate or buffer the long-term directional effects of climatic forcing. Taken together, our observations caution against over emphasizing the conclusions from short-term experiments and highlight the necessity to consider the temporal expression of complex system dynamics established over appropriate timescales when forecasting the likely ecological consequences of climatic forcing. PMID:23980249

  2. The Comparative Accuracy of Two Hydrologic Models in Simulating Warm-Season Runoff for Two Small, Hillslope Catchments

    EPA Science Inventory

    Runoff prediction is a cornerstone of water resources planning, and therefore modeling performance is a key issue. This paper investigates the comparative advantages of conceptual versus process- based models in predicting warm season runoff for upland, low-yield micro-catchments...

  3. Acclimation of light and dark respiration to experimental and seasonal warming are mediated by changes in leaf nitrogen in Eucalyptus globulus.

    PubMed

    Crous, K Y; Wallin, G; Atkin, O K; Uddling, J; Af Ekenstam, A

    2017-08-01

    Quantifying the adjustments of leaf respiration in response to seasonal temperature variation and climate warming is crucial because carbon loss from vegetation is a large but uncertain part of the global carbon cycle. We grew fast-growing Eucalyptus globulus Labill. trees exposed to +3 °C warming and elevated CO2 in 10-m tall whole-tree chambers and measured the temperature responses of leaf mitochondrial respiration, both in light (RLight) and in darkness (RDark), over a 20-40 °C temperature range and during two different seasons. RLight was assessed using the Laisk method. Respiration rates measured at a standard temperature (25 °C - R25) were higher in warm-grown trees and in the warm season, related to higher total leaf nitrogen (N) investment with higher temperatures (both experimental and seasonal), indicating that leaf N concentrations modulated the respiratory capacity to changes in temperature. Once differences in leaf N were accounted for, there were no differences in R25 but the Q10 (i.e., short-term temperature sensitivity) was higher in late summer compared with early spring. The variation in RLight between experimental treatments and seasons was positively correlated with carboxylation capacity and photorespiration. RLight was less responsive to short-term changes in temperature than RDark, as shown by a lower Q10 in RLight compared with RDark. The overall light inhibition of R was ∼40%. Our results highlight the dynamic nature of leaf respiration to temperature variation and that the responses of RLight do not simply mirror those of RDark. Therefore, it is important not to assume that RLight is the same as RDark in ecosystem models, as doing so may lead to large errors in predicting plant CO2 release and productivity. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Tradeoffs between global warming and day length on the start of the carbon uptake period in seasonally cold ecosystems.

    PubMed

    Wohlfahrt, Georg; Cremonese, Edoardo; Hammerle, Albin; Hörtnagl, Lukas; Galvagno, Marta; Gianelle, Damiano; Marcolla, Barbara; di Cella, Umberto Morra

    2013-12-16

    It is well established that warming leads to longer growing seasons in seasonally cold ecosystems. Whether this goes along with an increase in the net ecosystem carbon dioxide (CO 2 ) uptake is much more controversial. We studied the effects of warming on the start of the carbon uptake period (CUP) of three mountain grasslands situated along an elevational gradient in the Alps. To this end we used a simple empirical model of the net ecosystem CO 2 exchange, calibrated and forced with multi-year empirical data from each site. We show that reductions in the quantity and duration of daylight associated with earlier snowmelts were responsible for diminishing returns, in terms of carbon gain, from longer growing seasons caused by reductions in daytime photosynthetic uptake and increases in nighttime losses of CO 2 . This effect was less pronounced at high, compared to low, elevations, where the start of the CUP occurred closer to the summer solstice when changes in day length and incident radiation are minimal.

  5. Nephrolithiasis, stone composition, meteorology, and seasons in Malta: Is there any connection?

    PubMed

    Buttigieg, Jesmar; Attard, Stephanie; Carachi, Alexander; Galea, Ruth; Fava, Stephen

    2016-01-01

    The effect of seasons and meteorology on the incidence of nephrolithiasis has been studied in various regions around the globe, but seldom in the Mediterranean. This retrospective analysis aims at investigating these putative effects in the Maltese Islands, whose climate is typically Mediterranean, followed by a systematic review of the literature. Submission rate and chemical composition of all kidney stones after spontaneous passage or surgical removal between January 2009 and December 2011 were analyzed according to seasons and corresponding meteorology. A total of 389 stones were analyzed. A higher stone submission rate was observed in summer compared to winter (31.6% vs. 20.8%, P = 0.0008) and in the warm period compared to the cold period (57.1% vs. 42.9%, P = 0.0001). Significant correlation was established between the monthly number of stones and mean monthly maximum temperature (r = 0.50, P = 0.002), mean monthly temperature (r = 0.49, P = 0.003) and mean monthly Humidex (r = 0.49, P = 0.007). Humidex was found to be an independent predictor for stone submission (β = 0.49, P = 0.007). The majority of stones contained calcium (83.3%), combined with oxalate (77.6%), phosphate (14.7%), and carbonate (2.8%). Some stones (11.8%) contained a mixture of >1 negatively charged molecules. Urate (11.6%), cysteine (4.6%), and ammonium-magnesium-phosphate (0.5%) constituted the rest. There was no association between chemical composition and seasons. Literature review included 25 articles. Higher ambient temperature and warm seasons were the most commonly encountered risk factors for both presentation and etiology of nephrolithiasis. A significant positive correlation was noted between ambient temperature and stone submission rate, which was significantly higher during the warm months in Malta.

  6. Monthly and Seasonal Cloud Cover Patterns at the Manila Observatory (14.64°N, 121.08°E)

    NASA Astrophysics Data System (ADS)

    Antioquia, C. T.; Lagrosas, N.; Caballa, K.

    2014-12-01

    A ground based sky imaging system was developed at the Manila Observatory in 2012 to measure cloud occurrence and to analyse seasonal variation of cloud cover over Metro Manila. Ground-based cloud occurrence measurements provide more reliable results compared to satellite observations. Also, cloud occurrence data aid in the analysis of radiation budget in the atmosphere. In this study, a GoPro Hero 2 with almost 180o field of view is employed to take pictures of the atmosphere. These pictures are taken continuously, having a temporal resolution of 1min. Atmospheric images from April 2012 to June 2013 (excluding the months of September, October, and November 2012) were processed to determine cloud cover. Cloud cover in an image is measured as the ratio of the number of pixels with clouds present in them to the total number of pixels. The cloud cover values were then averaged over each month to know its monthly and seasonal variation. In Metro Manila, the dry season occurs in the months of November to May of the next year, while the wet season occurs in the months of June to October of the same year. Fig 1 shows the measured monthly variation of cloud cover. No data was collected during the months of September (wherein the camera was used for the 7SEAS field campaign), October, and November 2012 (due to maintenance and repairs). Results show that there is high cloud cover during the wet season months (80% on average) while there is low cloud cover during the dry season months (62% on average). The lowest average cloud cover for a wet season month occurred in June 2012 (73%) while the highest average cloud cover for a wet season month occurred in June 2013 (86%). The variations in cloud cover average in this season is relatively smaller compared to that of the dry season wherein the lowest average cloud cover in a month was during April 2012 (38%) while the highest average cloud cover in a month was during January 2013 (77%); minimum and maximum averages being 39

  7. Design and performance of combined infrared canopy and belowground warming in the B4WarmED (Boreal Forest Warming at an Ecotone in Danger) experiment.

    PubMed

    Rich, Roy L; Stefanski, Artur; Montgomery, Rebecca A; Hobbie, Sarah E; Kimball, Bruce A; Reich, Peter B

    2015-06-01

    Conducting manipulative climate change experiments in complex vegetation is challenging, given considerable temporal and spatial heterogeneity. One specific challenge involves warming of both plants and soils to depth. We describe the design and performance of an open-air warming experiment called Boreal Forest Warming at an Ecotone in Danger (B4WarmED) that addresses the potential for projected climate warming to alter tree function, species composition, and ecosystem processes at the boreal-temperate ecotone. The experiment includes two forested sites in northern Minnesota, USA, with plots in both open (recently clear-cut) and closed canopy habitats, where seedlings of 11 tree species were planted into native ground vegetation. Treatments include three target levels of plant canopy and soil warming (ambient, +1.7°C, +3.4°C). Warming was achieved by independent feedback control of voltage input to aboveground infrared heaters and belowground buried resistance heating cables in each of 72-7.0 m(2) plots. The treatments emulated patterns of observed diurnal, seasonal, and annual temperatures but with superimposed warming. For the 2009 to 2011 field seasons, we achieved temperature elevations near our targets with growing season overall mean differences (∆Tbelow ) of +1.84°C and +3.66°C at 10 cm soil depth and (∆T(above) ) of +1.82°C and +3.45°C for the plant canopies. We also achieved measured soil warming to at least 1 m depth. Aboveground treatment stability and control were better during nighttime than daytime and in closed vs. open canopy sites in part due to calmer conditions. Heating efficacy in open canopy areas was reduced with increasing canopy complexity and size. Results of this study suggest the warming approach is scalable: it should work well in small-statured vegetation such as grasslands, desert, agricultural crops, and tree saplings (<5 m tall). © 2015 John Wiley & Sons Ltd.

  8. NMME Monthly / Seasonal Forecasts for NASA SERVIR Applications Science

    NASA Technical Reports Server (NTRS)

    Robertson, Franklin R.; Roberts, Jason B.

    2014-01-01

    This work details use of the North American Multi-Model Ensemble (NMME) experimental forecasts as drivers for Decision Support Systems (DSSs) in the NASA / USAID initiative, SERVIR (a Spanish acronym meaning "to serve"). SERVIR integrates satellite observations, ground-based data and forecast models to monitor and forecast environmental changes and to improve response to natural disasters. Through the use of DSSs whose "front ends" are physically based models, the SERVIR activity provides a natural testbed to determine the extent to which NMME monthly to seasonal projections enable scientists, educators, project managers and policy implementers in developing countries to better use probabilistic outlooks of seasonal hydrologic anomalies in assessing agricultural / food security impacts, water availability, and risk to societal infrastructure. The multi-model NMME framework provides a "best practices" approach to probabilistic forecasting. The NMME forecasts are generated at resolution more coarse than that required to support DSS models; downscaling in both space and time is necessary. The methodology adopted here applied model output statistics where we use NMME ensemble monthly projections of sea-surface temperature (SST) and precipitation from 30 years of hindcasts with observations of precipitation and temperature for target regions. Since raw model forecasts are well-known to have structural biases, a cross-validated multivariate regression methodology (CCA) is used to link the model projected states as predictors to the predictands of the target region. The target regions include a number of basins in East and South Africa as well as the Ganges / Baramaputra / Meghna basin complex. The MOS approach used address spatial downscaling. Temporal disaggregation of monthly seasonal forecasts is achieved through use of a tercile bootstrapping approach. We interpret the results of these studies, the levels of skill by several metrics, and key uncertainties.

  9. NMME Monthly / Seasonal Forecasts for NASA SERVIR Applications Science

    NASA Astrophysics Data System (ADS)

    Robertson, F. R.; Roberts, J. B.

    2014-12-01

    This work details use of the North American Multi-Model Ensemble (NMME) experimental forecasts as drivers for Decision Support Systems (DSSs) in the NASA / USAID initiative, SERVIR (a Spanish acronym meaning "to serve"). SERVIR integrates satellite observations, ground-based data and forecast models to monitor and forecast environmental changes and to improve response to natural disasters. Through the use of DSSs whose "front ends" are physically based models, the SERVIR activity provides a natural testbed to determine the extent to which NMME monthly to seasonal projections enable scientists, educators, project managers and policy implementers in developing countries to better use probabilistic outlooks of seasonal hydrologic anomalies in assessing agricultural / food security impacts, water availability, and risk to societal infrastructure. The multi-model NMME framework provides a "best practices" approach to probabilistic forecasting. The NMME forecasts are generated at resolution more coarse than that required to support DSS models; downscaling in both space and time is necessary. The methodology adopted here applied model output statistics where we use NMME ensemble monthly projections of sea-surface temperature (SST) and precipitation from 30 years of hindcasts with observations of precipitation and temperature for target regions. Since raw model forecasts are well-known to have structural biases, a cross-validated multivariate regression methodology (CCA) is used to link the model projected states as predictors to the predictands of the target region. The target regions include a number of basins in East and South Africa as well as the Ganges / Baramaputra / Meghna basin complex. The MOS approach used address spatial downscaling. Temporal disaggregation of monthly seasonal forecasts is achieved through use of a tercile bootstrapping approach. We interpret the results of these studies, the levels of skill by several metrics, and key uncertainties.

  10. Seasonal greening of an Arctic ecosystem in response to early snowmelt and climate warming: do plant community responses differ from species responses?

    NASA Astrophysics Data System (ADS)

    Steltzer, H.; Weintraub, M. N.; Sullivan, P.; Wallenstein, M. D.; Schimel, J.; Darrouzet-Nardi, A.; Shory, R.; Livensperger, C.; Melle, C.; Segal, A. D.; Daly, K.; Tsosie, T.

    2011-12-01

    In the Arctic and around the world, earlier plant growth and a longer growing season are indications that warmer temperatures or other global changes are changing the seasonality of the Earth's ecosystems. These changes in plant life histories have multi-trophic level consequences that affect food webs and biogeochemical cycles. Both the response of the plant community and of individual species can affect food and habitat resources for animals or nutrient resources for microbes. Our aim was to determine if the response of an Arctic plant community differs from individual species responses to climate change. For two years in an early snowmelt and climate warming experiment in moist acidic tussock tundra, we observed the seasonal greening of the ecosystem through near-surface measurements of surface greenness and through direct observations of the timing of plant life history events for five to eight common species that differ in growth form. In 2010 when snowmelt was accelerated by 4 days, earlier snowmelt alone or in combination with climate warming extended the life history of the dominant graminoids (E. vaginatum and C. bigelowii) and willow (S. pulchra) by 3 to 4 days. For these species, new leaf production began earlier, while the timing of senescence was similar to the controls. The effect of earlier snowmelt on the life histories of birch (B. nana) and cranberry (V. vitis-idaea) was less, but warming alone tended to increase life history duration. Warming led to earlier leaf expansion for birch and delayed senescence for cranberry. We found that the onset of greening for the plant community began four days earlier, due to the earlier loss of snow cover, and that warming accelerated the rate of greening. Peak season ended 4 days earlier in response to earlier snowmelt and climate warming, due to earlier senescence by birch. In 2011, our manipulation of the snowpack by increasing energy absorption accelerated snowmelt by 15 days and control plots were snowfree

  11. Effect of feeding warm-season annuals with orchardgrass on ruminal fermentation and methane output in continuous culture

    USDA-ARS?s Scientific Manuscript database

    A 4-unit, dual-flow continuous culture fermentor system was used to assess nutrient digestibility, volatile fatty acids (VFA) production, bacterial protein synthesis and CH4 output of warm-season summer annual grasses. Treatments were randomly assigned to fermentors in a 4 × 4 Latin square design us...

  12. Linking the pacific decadal oscillation to seasonal stream discharge patterns in Southeast Alaska

    USGS Publications Warehouse

    Neal, E.G.; Todd, Walter M.; Coffeen, C.

    2002-01-01

    This study identified and examined differences in Southeast Alaskan streamflow patterns between the two most recent modes of the Pacific decadal oscillation (PDO). Identifying relationships between the PDO and specific regional phenomena is important for understanding climate variability, interpreting historical hydrological variability, and improving water-resources forecasting. Stream discharge data from six watersheds in Southeast Alaska were divided into cold-PDO (1947-1976) and warm-PDO (1977-1998) subsets. For all watersheds, the average annual streamflows during cold-PDO years were not significantly different from warm-PDO years. Monthly and seasonal discharges, however, did differ significantly between the two subsets, with the warm-PDO winter flows being typically higher than the cold-PDO winter flows and the warm-PDO summer flows being typically lower than the cold-PDO flows. These results were consistent with and driven by observed temperature and snowfall patterns for the region. During warm-PDO winters, precipitation fell as rain and ran-off immediately, causing higher than normal winter streamflow. During cold-PDO winters, precipitation was stored as snow and ran off during the summer snowmelt, creating greater summer streamflows. The Mendenhall River was unique in that it experienced higher flows for all seasons during the warm-PDO relative to the cold-PDO. The large amount of Mendenhall River discharge caused by glacial melt during warm-PDO summers offset any flow reduction caused by lack of snow accumulation during warm-PDO winters. The effect of the PDO on Southeast Alaskan watersheds differs from other regions of the Pacific Coast of North America in that monthly/seasonal discharge patterns changed dramatically with the switch in PDO modes but annual discharge did not. ?? 2002 Elsevier Science B.V. All rights reserved.

  13. Trade-offs between global warming and day length on the start of the carbon uptake period in seasonally cold ecosystems

    NASA Astrophysics Data System (ADS)

    Wohlfahrt, Georg; Cremonese, Edoardo; Hammerle, Albin; Hörtnagl, Lukas; Galvagno, Marta; Gianelle, Damiano; Marcolla, Barbara; Cella, Umberto Morra

    2013-12-01

    is well established that warming leads to longer growing seasons in seasonally cold ecosystems. Whether this goes along with an increase in the net ecosystem carbon dioxide (CO2) uptake is much more controversial. We studied the effects of warming on the start of the carbon uptake period (CUP) of three mountain grasslands situated along an elevational gradient in the Alps. To this end, we used a simple empirical model of the net ecosystem CO2 exchange, calibrated, and forced with multiyear empirical data from each site. We show that reductions in the quantity and duration of daylight associated with earlier snowmelts were responsible for diminishing returns, in terms of carbon gain, from longer growing seasons caused by reductions in daytime photosynthetic uptake and increases in nighttime losses of CO2. This effect was less pronounced at high, compared to low, elevations, where the start of the CUP occurred closer to the summer solstice when changes in day length and incident radiation are minimal.

  14. Analysis of vehicle classification data, including monthly and seasonal ADT factors, hourly distribution factors, and lane distribution factors

    DOT National Transportation Integrated Search

    1998-11-01

    This report documents the development of monthly and seasonal average daily traffic (ADT) factors for performing estimating AADTs. It appears that seasonal factors can estimate AADT as well as monthly factors, and it is recommended that seasonal fact...

  15. Perennial warm-season grasses for producing biofuel and enhancing soil properties: an alternative to corn residue removal

    USDA-ARS?s Scientific Manuscript database

    Removal of corn (Zea mays L.) residues at high rates for biofuel and other off-farm uses may negatively impact soil and the environment in the long term. Biomass removal from perennial warm-season grasses (WSGs) grown in marginally productive lands could be an alternative to corn residue removal as ...

  16. Warm season heavy rainfall events over the Huaihe River Valley and their linkage with wintertime thermal condition of the tropical oceans

    NASA Astrophysics Data System (ADS)

    Li, Laifang; Li, Wenhong; Tang, Qiuhong; Zhang, Pengfei; Liu, Yimin

    2016-01-01

    Warm season heavy rainfall events over the Huaihe River Valley (HRV) of China are amongst the top causes of agriculture and economic loss in this region. Thus, there is a pressing need for accurate seasonal prediction of HRV heavy rainfall events. This study improves the seasonal prediction of HRV heavy rainfall by implementing a novel rainfall framework, which overcomes the limitation of traditional probability models and advances the statistical inference on HRV heavy rainfall events. The framework is built on a three-cluster Normal mixture model, whose distribution parameters are sampled using Bayesian inference and Markov Chain Monte Carlo algorithm. The three rainfall clusters reflect probability behaviors of light, moderate, and heavy rainfall, respectively. Our analysis indicates that heavy rainfall events make the largest contribution to the total amount of seasonal precipitation. Furthermore, the interannual variation of summer precipitation is attributable to the variation of heavy rainfall frequency over the HRV. The heavy rainfall frequency, in turn, is influenced by sea surface temperature anomalies (SSTAs) over the north Indian Ocean, equatorial western Pacific, and the tropical Atlantic. The tropical SSTAs modulate the HRV heavy rainfall events by influencing atmospheric circulation favorable for the onset and maintenance of heavy rainfall events. Occurring 5 months prior to the summer season, these tropical SSTAs provide potential sources of prediction skill for heavy rainfall events over the HRV. Using these preceding SSTA signals, we show that the support vector machine algorithm can predict HRV heavy rainfall satisfactorily. The improved prediction skill has important implication for the nation's disaster early warning system.

  17. A warm-season comparison of WRF coupled to the CLM4.0, Noah-MP, and Bucket hydrology land surface schemes over the central USA

    NASA Astrophysics Data System (ADS)

    Van Den Broeke, Matthew S.; Kalin, Andrew; Alavez, Jose Abraham Torres; Oglesby, Robert; Hu, Qi

    2017-11-01

    In climate modeling studies, there is a need to choose a suitable land surface model (LSM) while adhering to available resources. In this study, the viability of three LSM options (Community Land Model version 4.0 [CLM4.0], Noah-MP, and the five-layer thermal diffusion [Bucket] scheme) in the Weather Research and Forecasting model version 3.6 (WRF3.6) was examined for the warm season in a domain centered on the central USA. Model output was compared to Parameter-elevation Relationships on Independent Slopes Model (PRISM) data, a gridded observational dataset including mean monthly temperature and total monthly precipitation. Model output temperature, precipitation, latent heat (LH) flux, sensible heat (SH) flux, and soil water content (SWC) were compared to observations from sites in the Central and Southern Great Plains region. An overall warm bias was found in CLM4.0 and Noah-MP, with a cool bias of larger magnitude in the Bucket model. These three LSMs produced similar patterns of wet and dry biases. Model output of SWC and LH/SH fluxes were compared to observations, and did not show a consistent bias. Both sophisticated LSMs appear to be viable options for simulating the effects of land use change in the central USA.

  18. The recent warming of permafrost in Alaska

    NASA Astrophysics Data System (ADS)

    Osterkamp, T. E.

    2005-12-01

    This paper reports results of an experiment initiated in 1977 to determine the effects of climate on permafrost in Alaska. Permafrost observatories with boreholes were established along a north-south transect of Alaska in undisturbed permafrost terrain. The analysis and interpretation of annual temperature measurements in the boreholes and daily temperature measurements of the air, ground and permafrost surfaces made with automated temperature loggers are reported. Permafrost temperatures warmed along this transect coincident with a statewide warming of air temperatures that began in 1977. At two sites on the Arctic Coastal Plain, the warming was seasonal, greatest during "winter" months (October through May) and least during "summer" months (June through September). Permafrost temperatures peaked in the early 1980s and then decreased in response to slightly cooler air temperatures and thinner snow covers. Arctic sites began warming again typically about 1986 and Interior Alaska sites about 1988. Gulkana, the southernmost site, has been warming slowly since it was drilled in 1983. Air temperatures were relatively warm and snow covers were thicker-than-normal from the late 1980s into the late 1990s allowing permafrost temperatures to continue to warm. Temperatures at some sites leveled off or cooled slightly at the turn of the century. Two sites (Yukon River Bridge and Livengood) cooled during the period of observations. The magnitude of the total warming at the surface of the permafrost (through 2003) was 3 to 4 °C for the Arctic Coastal Plain, 1 to 2 °C for the Brooks Range including its northern and southern foothills, and 0.3 to 1 °C south of the Yukon River. While the data are sparse, permafrost is warming throughout the region north of the Brooks Range, southward along the transect from the Brooks Range to the Chugach Mountains (except for Yukon River and Livengood), in Interior Alaska throughout the Tanana River region, and in the region south of the

  19. Monthly and seasonally verification of precipitation in Poland

    NASA Astrophysics Data System (ADS)

    Starosta, K.; Linkowska, J.

    2009-04-01

    The national meteorological service of Poland - the Institute of Meteorology and Water Management (IMWM) joined COSMO - The Consortium for Small Scale Modelling on July 2004. In Poland, the COSMO _PL model version 3.5 had run till June 2007. Since July 2007, the model version 4.0 has been running. The model runs in an operational mode at 14-km grid spacing, twice a day (00 UTC, 12 UTC). For scientific research also model with 7-km grid spacing is ran. Monthly and seasonally verification for the 24-hours (06 UTC - 06 UTC) accumulated precipitation is presented in this paper. The precipitation field of COSMO_LM had been verified against rain gauges network (308 points). The verification had been made for every month and all seasons from December 2007 to December 2008. The verification was made for three forecast days for selected thresholds: 0.5, 1, 2.5, 5, 10, 20, 25, 30 mm. Following indices from contingency table were calculated: FBI (bias), POD (probability of detection), PON (probability of detection of non event), FAR (False alarm rate), TSS (True sill statistic), HSS (Heidke skill score), ETS (Equitable skill score). Also percentile ranks and ROC-relative operating characteristic are presented. The ROC is a graph of the hit rate (Y-axis) against false alarm rate (X-axis) for different decision thresholds

  20. Monthly and seasonally verification of precipitation in Poland

    NASA Astrophysics Data System (ADS)

    Starosta, K.; Linkowska, J.

    2009-04-01

    The national meteorological service of Poland - the Institute of Meteorology and Water Management (IMWM) joined COSMO - The Consortium for Small Scale Modelling on July 2004. In Poland, the COSMO _PL model version 3.5 had run till June 2007. Since July 2007, the model version 4.0 has been running. The model runs in an operational mode at 14-km grid spacing, twice a day (00 UTC, 12 UTC). For scientific research also model with 7-km grid spacing is ran. Monthly and seasonally verification for the 24-hours (06 UTC - 06 UTC) accumulated precipitation is presented in this paper. The precipitation field of COSMO_LM had been verified against rain gauges network (308 points). The verification had been made for every month and all seasons from December 2007 to December 2008. The verification was made for three forecast days for selected thresholds: 0.5, 1, 2.5, 5, 10, 20, 25, 30 mm. Following indices from contingency table were calculated: FBI (bias), POD (probability of detection), PON (probability of detection of non event), FAR (False alarm rate), TSS (True sill statistic), HSS (Heidke skill score), ETS (Equitable skill score). Also percentile ranks and ROC-relative operating characteristic are presented. The ROC is a graph of the hit rate (Y-axis) against false alarm rate (X-axis) for different decision thresholds.

  1. Projections of Seasonal Patterns in Temperature- Related Deaths for Manhattan, New York

    NASA Technical Reports Server (NTRS)

    Li, Tiantian; Horton, Radley M.; Kinney, Patrick L.

    2013-01-01

    Global average temperatures have been rising for the past half-century, and the warming trend has accelerated in recent decades. Further warming is expected over the next few decades, with significant regional variations. These warming trends will probably result in more frequent, intense and persistent periods of hot temperatures in summer, and generally higher temperatures in winter. Daily death counts in cities increase markedly when temperatures reach levels that are very high relative to what is normal in a given location. Relatively cold temperatures also seem to carry risk. Rising temperatures may result in more heat-related mortality but may also reduce cold-related mortality, and the net impact on annual mortality remains uncertain. Here we use 16 downscaled global climate models and two emissions scenarios to estimate present and future seasonal patterns in temperature-related mortality in Manhattan, New York. All 32 projections yielded warm-season increases and cold-season decreases in temperature-related mortality, with positive net annual temperature-related deaths in all cases. Monthly analyses showed that the largest percentage increases may occur in May and September. These results suggest that, over a range of models and scenarios of future greenhouse gas emissions, increases in heat-related mortality could outweigh reductions in cold-related mortality, with shifting seasonal patterns.

  2. The occurrence of convective systems with a bow echo in warm season in Poland

    NASA Astrophysics Data System (ADS)

    Celiński-Mysław, Daniel; Palarz, Angelika

    2017-09-01

    The characteristics of occurrence of convective systems with a bow echo in Poland in the warm season between 2007 and 2014 were presented. Using the identification criteria proposed by Fujita (1978), Burke and Schultz (2004), Klimowski et al. (2000, 2004), and supplemented by Gatzen (2013), 91 bow echo cases were identified in the analysed period. Depending on the year, the maximum number of cases usually occurred in July or August. From the multi-annual perspective, 28 and 30 cases occurred in those months. The diurnal variation of bow echo occurrences showed that it developed, or entered the Polish territory, usually between the hours of 13:00 UTC and 21:00 UTC, while it disappeared or receded beyond the country border in the hours between 15:00 UTC and 23:00 UTC. The areas most exposed to the occurrence of bow echo included the northern part of Lubuskie and Wielkopolska provinces, the southern part of West Pomerania province, Łódź province and Silesia province. In the period studied, the south-western direction of movement of convective systems with a bow echo was prevalent. This direction changed, however, depending on the region and the month of occurrence. The type and development mode of a bow echo, as well as synoptic conditions conducive to its occurrence were defined for selected cases. The results showed that BECs (bow-echo complex) and BEs (classic bow echo) were the predominant types (respectively 43 and 29 cases). Bow echoes developed most frequently from a squall line, or from a combination of a few, often weakly organized convective cells.

  3. Snowfall less sensitive to warming in Karakoram than in Himalayas due to a unique seasonal cycle

    USGS Publications Warehouse

    Kapnick, Sarah B.; Delworth, Thomas L.; Ashfaq, Moetasim; Malyshev, Sergey; Milly, Paul C.D.

    2014-01-01

    The high mountains of Asia, including the Karakoram, Himalayas and Tibetan Plateau, combine to form a region of perplexing hydroclimate changes. Glaciers have exhibited mass stability or even expansion in the Karakoram region1, 2, 3, contrasting with glacial mass loss across the nearby Himalayas and Tibetan Plateau1, 4, a pattern that has been termed the Karakoram anomaly. However, the remote location, complex terrain and multi-country fabric of high-mountain Asia have made it difficult to maintain longer-term monitoring systems of the meteorological components that may have influenced glacial change. Here we compare a set of high-resolution climate model simulations from 1861 to 2100 with the latest available observations to focus on the distinct seasonal cycles and resulting climate change signatures of Asia’s high-mountain ranges. We find that the Karakoram seasonal cycle is dominated by non-monsoonal winter precipitation, which uniquely protects it from reductions in annual snowfall under climate warming over the twenty-first century. The simulations show that climate change signals are detectable only with long and continuous records, and at specific elevations. Our findings suggest a meteorological mechanism for regional differences in the glacier response to climate warming.

  4. Seasonal body size reductions with warming covary with major body size gradients in arthropod species.

    PubMed

    Horne, Curtis R; Hirst, Andrew G; Atkinson, David

    2017-03-29

    Major biological and biogeographical rules link body size variation with latitude or environmental temperature, and these rules are often studied in isolation. Within multivoltine species, seasonal temperature variation can cause substantial changes in adult body size, as subsequent generations experience different developmental conditions. Yet, unlike other size patterns, these common seasonal temperature-size gradients have never been collectively analysed. We undertake the largest analysis to date of seasonal temperature-size gradients in multivoltine arthropods, including 102 aquatic and terrestrial species from 71 global locations. Adult size declines in warmer seasons in 86% of the species examined. Aquatic species show approximately 2.5-fold greater reduction in size per °C of warming than terrestrial species, supporting the hypothesis that greater oxygen limitation in water than in air forces aquatic species to exhibit greater plasticity in body size with temperature. Total percentage change in size over the annual cycle appears relatively constant with annual temperature range but varies between environments, such that the overall size reduction in aquatic-developing species (approx. 31%) is almost threefold greater than in terrestrial species (approx. 11%). For the first time, we show that strong correlations exist between seasonal temperature-size gradients, laboratory responses and latitudinal-size clines, suggesting that these patterns share common drivers. © 2017 The Author(s).

  5. Spatial and Seasonal Calcification in Corals and Calcareous Crusts in a Naturally Warm Coral Reef Region

    NASA Astrophysics Data System (ADS)

    Roik, A.; Roder, C.; Roethig, T.; Voolstra, C. R.

    2016-02-01

    The Red Sea harbors highly diverse and structurally complex coral reefs and is of interest for ocean warming studies. In the central and southern part, water temperatures rise above 30°C during summer, constituting one of the warmest coral reef environments worldwide. Additionally, seasonal variability of temperatures allows studying changes of environmental conditions and their effects on coral reef processes. To explore the influence of these warm and seasonally variable habitats on reef calcification, we measured in situ calcification of primary and secondary reef-builders in the central Red Sea. We collected calcification rates on the major habitat-forming coral genera Porites, Acropora, and Pocillopora, and also on calcareous crusts (CC). The study comprised forereef and backreef environments of three reefs along a cross-shelf gradient assessed over four seasons of the year. Calcification patterns of all coral genera were consistent across the shelf and highest in spring. In contrast to the corals, CC calcification strongly increased with distance from shore, but varied to a lesser extend over the seasons demonstrating lower calcification rates during spring and summer. Interestingly, reef calcification rates in the central Red Sea were on average in the range of data reported from the Caribbean and Indo-Pacific. For Acropora, annual average calcification rates were even at the lower end in comparison to studies from other locations. While coral calcification maxima typically have been observed during summer in many reef locations worldwide, we observed calcification maxima during spring in the central Red Sea indicating that summer temperatures may exceed the optima of reef calcifiers. Our study provides a baseline of calcification data for the region and serves as a foundation for comparative efforts to quantify the impact of future environmental change.

  6. Role of eruption season in reconciling model and proxy responses to tropical volcanism

    NASA Astrophysics Data System (ADS)

    Stevenson, Samantha; Fasullo, John T.; Otto-Bliesner, Bette L.; Tomas, Robert A.; Gao, Chaochao

    2017-02-01

    The response of the El Niño/Southern Oscillation (ENSO) to tropical volcanic eruptions has important worldwide implications, but remains poorly constrained. Paleoclimate records suggest an “El Niño-like” warming 1 year following major eruptions [Adams JB, Mann ME, Ammann CM (2003) Nature 426:274-278] and “La Niña-like” cooling within the eruption year [Li J, et al. (2013) Nat Clim Chang 3:822-826]. However, climate models currently cannot capture all these responses. Many eruption characteristics are poorly constrained, which may contribute to uncertainties in model solutions—for example, the season of eruption occurrence is often unknown and assigned arbitrarily. Here we isolate the effect of eruption season using experiments with the Community Earth System Model (CESM), varying the starting month of two large tropical eruptions. The eruption-year atmospheric circulation response is strongly seasonally dependent, with effects on European winter warming, the Intertropical Convergence Zone, and the southeast Asian monsoon. This creates substantial variations in eruption-year hydroclimate patterns, which do sometimes exhibit La Niña-like features as in the proxy record. However, eruption-year equatorial Pacific cooling is not driven by La Niña dynamics, but strictly by transient radiative cooling. In contrast, equatorial warming the following year occurs for all starting months and operates dynamically like El Niño. Proxy reconstructions confirm these results: eruption-year cooling is insignificant, whereas warming in the following year is more robust. This implies that accounting for the event season may be necessary to describe the initial response to volcanic eruptions and that climate models may be more accurately simulating volcanic influences than previously thought.

  7. Role of eruption season in reconciling model and proxy responses to tropical volcanism.

    PubMed

    Stevenson, Samantha; Fasullo, John T; Otto-Bliesner, Bette L; Tomas, Robert A; Gao, Chaochao

    2017-02-21

    The response of the El Niño/Southern Oscillation (ENSO) to tropical volcanic eruptions has important worldwide implications, but remains poorly constrained. Paleoclimate records suggest an "El Niño-like" warming 1 year following major eruptions [Adams JB, Mann ME, Ammann CM (2003) Nature 426:274-278] and "La Niña-like" cooling within the eruption year [Li J, et al. (2013) Nat Clim Chang 3:822-826]. However, climate models currently cannot capture all these responses. Many eruption characteristics are poorly constrained, which may contribute to uncertainties in model solutions-for example, the season of eruption occurrence is often unknown and assigned arbitrarily. Here we isolate the effect of eruption season using experiments with the Community Earth System Model (CESM), varying the starting month of two large tropical eruptions. The eruption-year atmospheric circulation response is strongly seasonally dependent, with effects on European winter warming, the Intertropical Convergence Zone, and the southeast Asian monsoon. This creates substantial variations in eruption-year hydroclimate patterns, which do sometimes exhibit La Niña-like features as in the proxy record. However, eruption-year equatorial Pacific cooling is not driven by La Niña dynamics, but strictly by transient radiative cooling. In contrast, equatorial warming the following year occurs for all starting months and operates dynamically like El Niño. Proxy reconstructions confirm these results: eruption-year cooling is insignificant, whereas warming in the following year is more robust. This implies that accounting for the event season may be necessary to describe the initial response to volcanic eruptions and that climate models may be more accurately simulating volcanic influences than previously thought.

  8. Effects of Global Warming on Predatory Bugs Supported by Data Across Geographic and Seasonal Climatic Gradients

    PubMed Central

    Schuldiner-Harpaz, Tarryn; Coll, Moshe

    2013-01-01

    Global warming may affect species abundance and distribution, as well as temperature-dependent morphometric traits. In this study, we first used historical data to document changes in Orius (Heteroptera: Anthocoridae) species assemblage and individual morphometric traits over the past seven decades in Israel. We then tested whether these changes could have been temperature driven by searching for similar patterns across seasonal and geographic climatic gradients in a present survey. The historical records indicated a shift in the relative abundance of dominant Orius species; the relative abundance of O. albidipennis, a desert-adapted species, increased while that of O. laevigatus decreased in recent decades by 6 and 10–15 folds, respectively. These shifts coincided with an overall increase of up to 2.1°C in mean daily temperatures over the last 25 years in Israel. Similar trends were found in contemporary data across two other climatic gradients, seasonal and geographic; O. albidipennis dominated Orius assemblages under warm conditions. Finally, specimens collected in the present survey were significantly smaller than those from the 1980’s, corresponding to significantly smaller individuals collected now during warmer than colder seasons. Taken together, results provide strong support to the hypothesis that temperature is the most likely driver of the observed shifts in species composition and body sizes because (1) historical changes in both species assemblage and body size were associated with rising temperatures in the study region over the last few decades; and (2) similar changes were observed as a result of contemporary drivers that are associated with temperature. PMID:23805249

  9. Evaluation of the North American Multi-Model Ensemble System for Monthly and Seasonal Prediction

    NASA Astrophysics Data System (ADS)

    Zhang, Q.

    2014-12-01

    Since August 2011, the real time seasonal forecasts of the U.S. National Multi-Model Ensemble (NMME) have been made on 8th of each month by NCEP Climate Prediction Center (CPC). The participating models were NCEP/CFSv1&2, GFDL/CM2.2, NCAR/U.Miami/COLA/CCSM3, NASA/GEOS5, IRI/ ECHAM-a & ECHAM-f in the first year of the real time NMME forecast. Two Canadian coupled models CMC/CanCM3 and CM4 joined in and CFSv1 and IRI's models dropped out in the second year. The NMME team at CPC collects monthly means of three variables, precipitation, temperature at 2m and sea surface temperature from each modeling center on a 1x1 global grid, removes systematic errors, makes the grand ensemble mean in equal weight for each model mean and probability forecast with equal weight for each member of each model. This provides the NMME forecast locked in schedule for the CPC operational seasonal and monthly outlook. The basic verification metrics of seasonal and monthly prediction of NMME are calculated as an evaluation of skill, including both deterministic and probabilistic forecasts for the 3-year real time (August, 2011- July 2014) period and the 30-year retrospective forecast (1982-2011) of the individual models as well as the NMME ensemble. The motivation of this study is to provide skill benchmarks for future improvements of the NMME seasonal and monthly prediction system. We also want to establish whether the real time and hindcast periods (used for bias correction in real time) are consistent. The experimental phase I of the project already supplies routine guidance to users of the NMME forecasts.

  10. Contrasting patterns of litterfall seasonality and seasonal changes in litter decomposability in a tropical rainforest region

    NASA Astrophysics Data System (ADS)

    Parsons, S. A.; Valdez-Ramirez, V.; Congdon, R. A.; Williams, S. E.

    2014-09-01

    The seasonality of litter inputs in forests has important implications for understanding ecosystem processes and biogeochemical cycles. We quantified the drivers of seasonality in litterfall and leaf decomposability using plots throughout the Australian wet tropical region. Litter fell mostly in the summer (wet, warm) months in the region, but other peaks occurred throughout the year. Litterfall seasonality was modelled well with the level of deciduousness of the site (plots with more deciduous species had lower seasonality than evergreen plots), temperature (higher seasonality in the uplands), disturbance (lower seasonality with more early secondary species) and soil fertility (higher seasonality with higher N : P/P limitation) (SL total litterfall model 1 = deciduousness + soil N : P + early secondary sp.: r2 = 0.63, n = 30; model 2 = temperature + early secondary sp. + soil N : P: r2 = 0.54, n = 30; SL leaf = temperature + early secondary sp. + rainfall seasonality: r2 = 0.39, n = 30). Leaf litter decomposability was lower in the dry season than in the wet season, driven by higher phenolic concentrations in the dry, with the difference exacerbated particularly by lower dry season moisture. Our results are contrary to the global trend for tropical rainforests; in that seasonality of litterfall input was generally higher in wetter, cooler, evergreen forests, compared to generally drier, warmer, semi-deciduous sites that had more uniform monthly inputs. We consider this due to more diverse litter shedding patterns in semi-deciduous and raingreen rainforest sites, and an important consideration for ecosystem modellers. Seasonal changes in litter quality are likely to have impacts on decomposition and biogeochemical cycles in these forests due to the litter that falls in the dry season being more recalcitrant to decay.

  11. Antarctica: Cooling or Warming?

    NASA Astrophysics Data System (ADS)

    Bunde, Armin; Ludescher, Josef; Franzke, Christian

    2013-04-01

    We consider the 14 longest instrumental monthly mean temperature records from the Antarctica and analyse their correlation properties by wavelet and detrended fluctuation analysis. We show that the stations in the western and the eastern part of the Antarctica show significant long-term memory governed by Hurst exponents close to 0.8 and 0.65, respectively. In contrast, the temperature records at the inner part of the continent (South Pole and Vostok), resemble white noise. We use linear regression to estimate the respective temperature differences in the records per decade (i) for the annual data, (ii) for the summer and (iii) for the winter season. Using a recent approach by Lennartz and Bunde [1] we estimate the respective probabilities that these temperature differences can be exceeded naturally without inferring an external (anthropogenic) trend. We find that the warming in the western part of the continent and the cooling at the South Pole is due to a gradually changes in the cold extremes. For the winter months, both cooling and warming are well outside the 95 percent confidence interval, pointing to an anthropogenic origin. In the eastern Antarctica, the temperature increases and decreases are modest and well within the 95 percent confidence interval. [1] S. Lennartz and A. Bunde, Phys. Rev. E 84, 021129 (2011)

  12. Global warming and South Indian monsoon rainfall-lessons from the Mid-Miocene.

    PubMed

    Reuter, Markus; Kern, Andrea K; Harzhauser, Mathias; Kroh, Andreas; Piller, Werner E

    2013-04-01

    Precipitation over India is driven by the Indian monsoon. Although changes in this atmospheric circulation are caused by the differential seasonal diabatic heating of Asia and the Indo-Pacific Ocean, it is so far unknown how global warming influences the monsoon rainfalls regionally. Herein, we present a Miocene pollen flora as the first direct proxy for monsoon over southern India during the Middle Miocene Climate Optimum. To identify climatic key parameters, such as mean annual temperature, warmest month temperature, coldest month temperature, mean annual precipitation, mean precipitation during the driest month, mean precipitation during the wettest month and mean precipitation during the warmest month the Coexistence Approach is applied. Irrespective of a ~ 3-4 °C higher global temperature during the Middle Miocene Climate Optimum, the results indicate a modern-like monsoonal precipitation pattern contrasting marine proxies which point to a strong decline of Indian monsoon in the Himalaya at this time. Therefore, the strength of monsoon rainfall in tropical India appears neither to be related to global warming nor to be linked with the atmospheric conditions over the Tibetan Plateau. For the future it implies that increased global warming does not necessarily entail changes in the South Indian monsoon rainfall.

  13. Climate Warming and Seasonal Precipitation Change Interact to Limit Species Distribution Shifts across Western North America

    PubMed Central

    Harsch, Melanie A.; HilleRisLambers, Janneke

    2016-01-01

    Using an extensive network of occurrence records for 293 plant species collected over the past 40 years across a climatically diverse geographic section of western North America, we find that plant species distributions were just as likely to shift upwards (i.e., towards higher elevations) as downward (i.e., towards lower elevations)–despite consistent warming across the study area. Although there was no clear directional response to climate warming across the entire study area, there was significant region- to region- variation in responses (i.e. from as many as 73% to as few as 32% of species shifting upward). To understand the factors that might be controlling region-specific distributional shifts of plant species, we explored the relationship between the direction of change in distribution limits and the nature of recent climate change. We found that the direction that distribution limits shifted was explained by an interaction between the rate of change in local summer temperatures and seasonal precipitation. Specifically, species were more likely to shift upward at their upper elevational limit when minimum temperatures increased and snowfall was unchanging or declined at slower rates (<0.5 mm/year). This suggests that both low temperature and water availability limit upward shifts at upper elevation limits. By contrast, species were more likely to shift upwards at their lower elevation limit when maximum temperatures increased, but also shifted upwards under conditions of cooling temperatures when precipitation decreased. This suggests increased water stress may drive upward shifts at lower elevation limits. Our results suggest that species’ elevational distribution shifts are not predictable by climate warming alone but depend on the interaction between seasonal temperature and precipitation change. PMID:27447834

  14. Contrasting patterns of litterfall seasonality and seasonal changes in litter decomposability in a tropical rainforest region

    NASA Astrophysics Data System (ADS)

    Parsons, S. A.; Valdez-Ramirez, V.; Congdon, R. A.; Williams, S. E.

    2014-06-01

    The seasonality of litter inputs in forests has important implications for understanding ecosystem processes and biogeochemical cycles. We quantified the drivers of seasonality in litterfall and leaf decomposability, using plots throughout the Australian wet tropical region. Litter fell mostly in the summer (wet, warm) months in the region, but other peaks occurred throughout the year. Litterfall seasonality was modelled well with the level of deciduousness of the site (plots with more deciduous species had lower seasonality than evergreen plots), temperature (higher seasonality in the uplands), disturbance (lower seasonality with more early secondary species) and soil fertility (higher seasonality with higher N : P/P limitation) (SL total litterfall model 1 = deciduousness + soil N : P + early secondary sp: r2 = 0.63, n = 30 plots; model 2 = temperature + early secondary sp. + soil N : P: r2 = 0.54, n = 30; SL leaf = temperature + early secondary sp. + rainfall seasonality: r2 = 0.39, n = 30). Leaf litter decomposability was lower in the dry season than in the wet season, driven by higher phenolic concentrations in the dry, with the difference exacerbated particularly by lower dry season moisture. Our results are contrary to the global trend for tropical rainforests; in that seasonality of litterfall inputs were generally higher in wetter, cooler, evergreen forests, compared to generally drier, warmer, semi-deciduous sites that had more uniform monthly inputs. We consider this due to more diverse litter shedding patterns in semi-deciduous and raingreen rainforest sites, and an important consideration for ecosystem modellers. Seasonal changes in litter quality are likely to have impacts on decomposition and biogeochemical cycles in these forests due to the litter that falls in the dry being more recalcitrant to decay.

  15. Warm season tree growth and precipitation over Mexico

    NASA Astrophysics Data System (ADS)

    Therrell, Matthew D.; Stahle, David W.; Cleaveland, Malcolm K.; Villanueva-Diaz, Jose

    2002-07-01

    We have developed a network of 18 new tree ring chronologies to examine the history of warm season tree growth over Mexico from 1780 to 1992. The chronologies include Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) and Montezuma pine (Pinus montezumae Lamb.) latewood width, and Montezuma bald cypress (Taxodium mucronatum Ten.) total ring width. They are located in southwestern Texas, the Sierra Madre Oriental, Sierra Madre Occidental, and southern Mexico as far south as Oaxaca. Seven of these chronologies are among the first precipitation sensitive tree ring records from the American tropics. Principal component analysis of the chronologies indicates that the primary modes of tree growth variability are divided north and south by the Tropic of Cancer. The tree ring data in northern Mexico (PC1) are most sensitive to June-August rainfall, while the data from southern Mexico (PC2) are sensitive to rainfall in April-June. We find that the mode of tree growth variability over southern Mexico is significantly correlated with the onset of the North American Monsoon. Anomalies in monsoon onset, spring precipitation, and tree growth in southern Mexico all tend to be followed by precipitation anomalies of opposite sign later in the summer over most of central Mexico.

  16. For everything a season? A month-by-month analysis of social network resources in later life.

    PubMed

    Upenieks, Laura; Settels, Jason; Schafer, Markus H

    2018-01-01

    It is widely acknowledged that informal social ties provide older persons with many resources that serve to protect and improve their levels of health and well-being. Most studies on this topic, however, ignore the month or season of the year during which data was accumulated. This study proposes two hypotheses to explain seniors' social network resources over the calendar year: the "fluctuation hypothesis", which proposes that seasonal variation, in the form of weather fluctuations, institutional calendars, and holidays, might influence the social lives and resources of older persons, and the "network stability" perspective, which, informed by tenets of convoy theory and socioemotional selectivity theory, emphasizes the increasing importance of close network ties as individuals age and the stability of these ties. Using two waves (2005-2006 and 2010-2011) of the National Social Life, Health, and Aging Project (NSHAP), a nationally representative sample of community-dwelling older adults aged 57-85 in the United States, we examine a diverse set of nine social connectedness outcomes. Results, overall, support the network stability perspective, as the only social connectedness outcome found to significantly vary by month of year was average closeness with network members. We conclude by suggesting some methodological considerations for survey research and by noting how these findings complement the growing literature on inter-year fluctuation in social networks and social support. Changes in older adults' networks, while frequently observable over the course of years, do not seem to be seasonally patterned. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. On statistical irregularity of stratospheric warming occurrence during northern winters

    NASA Astrophysics Data System (ADS)

    Savenkova, Elena N.; Gavrilov, Nikolai M.; Pogoreltsev, Alexander I.

    2017-10-01

    Statistical analysis of dates of warming events observed during the years 1981-2016 at different stratospheric altitudes reveals their non-uniform distributions during northern winter months with maxima at the beginning of January, at the end of January - beginning of February and at the end of February. Climatology of zonal-mean zonal wind, deviations of temperature from its winter-averaged values, and planetary wave (PW) characteristics at high and middle northern latitudes in the altitude range from the ground up to 60 km is studied using the database of meteorological reanalysis MERRA. Climatological temperature deviations averaged over the 60-90°N latitudinal bands reveal cooler and warmer layers descending due to seasonal changes during the polar night. PW amplitudes and upward Eliassen-Palm fluxes averaged over 36 years have periodical maxima with the main maximum at the beginning of January at altitudes 40-50 km. During the above-mentioned intervals of more frequent occurrence of stratospheric warming events, maxima of PW amplitudes and Eliassen-Palm fluxes, also minima of eastward winds in the high-latitude northern stratosphere have been found. Climatological intra-seasonal irregularities of stratospheric warming dates could indicate reiterating phases of stratospheric vacillations in different years.

  18. Seasonal Variation in Month of Diagnosis of Polish Children with Type 1 Diabetes - A Multicenter Study.

    PubMed

    Szypowska, Agnieszka; Ramotowska, Anna; Wysocka-Mincewicz, Marta; Mazur, Artur; Lisowicz, Lucyna; Beń-Skowronek, Iwona; Sieniawska, Joanna; Klonowska, Bożenna; Charemska, Dorota; Nawrotek, Jolanta; Jałowiec, Irena; Bossowski, Artur; Jamiołkowska, Milena; Pyrżak, Beata; Miszkurka, Grażyna; Szalecki, Mieczysław

    2018-03-05

    The seasonal variation of incidence of type 1 diabetes (T1D) theory supports the hypothesis that environmental factors play a role in the onset of the disease. The aim of this study is to assess seasonality of month of diagnosis in children with T1D in Poland. the study group consisted of 2174 children from eastern and central Poland diagnosed with T1D between 2010 and 2014. Analysis was performed in different age groups, based on place of residence (rural/urban area) and depending on sex. We noted significant seasonality in the incidence of T1D with a peak in diagnosis of diabetes in January and the minimum rate in June. A total of 423 (19%) children were diagnosed in the warmest months (June to August with a mean temperature of 16.8°C) compared to 636 (29%) recognised in the coldest months (December to February with a mean temperature of -1.6°C), OR 0.57 95%CI [0.51-0.67], p<0.0001. We noted a more flat seasonal pattern in children 0-4 years of age compared with subjects 5-17 years old with a week correlation of trend comparison between both groups, r=0.69, p=0.001. Similar seasonal variation in the incidence of T1D was noted in children from urban and rural setting. For girls, seasonal pattern peaks were observed one month earlier as compared to boys. Seasonal variation in incidence of T1D diagnosis of Polish children supports the role of different environmental factors in diabetes onset. The majority of children were diagnosed with diabetes in autumn and winter. © Georg Thieme Verlag KG Stuttgart · New York.

  19. Role of eruption season in reconciling model and proxy responses to tropical volcanism

    PubMed Central

    Stevenson, Samantha; Fasullo, John T.; Otto-Bliesner, Bette L.; Tomas, Robert A.; Gao, Chaochao

    2017-01-01

    The response of the El Niño/Southern Oscillation (ENSO) to tropical volcanic eruptions has important worldwide implications, but remains poorly constrained. Paleoclimate records suggest an “El Niño-like” warming 1 year following major eruptions [Adams JB, Mann ME, Ammann CM (2003) Nature 426:274–278] and “La Niña-like” cooling within the eruption year [Li J, et al. (2013) Nat Clim Chang 3:822–826]. However, climate models currently cannot capture all these responses. Many eruption characteristics are poorly constrained, which may contribute to uncertainties in model solutions—for example, the season of eruption occurrence is often unknown and assigned arbitrarily. Here we isolate the effect of eruption season using experiments with the Community Earth System Model (CESM), varying the starting month of two large tropical eruptions. The eruption-year atmospheric circulation response is strongly seasonally dependent, with effects on European winter warming, the Intertropical Convergence Zone, and the southeast Asian monsoon. This creates substantial variations in eruption-year hydroclimate patterns, which do sometimes exhibit La Niña-like features as in the proxy record. However, eruption-year equatorial Pacific cooling is not driven by La Niña dynamics, but strictly by transient radiative cooling. In contrast, equatorial warming the following year occurs for all starting months and operates dynamically like El Niño. Proxy reconstructions confirm these results: eruption-year cooling is insignificant, whereas warming in the following year is more robust. This implies that accounting for the event season may be necessary to describe the initial response to volcanic eruptions and that climate models may be more accurately simulating volcanic influences than previously thought. PMID:28179573

  20. The potential effect of global warming on the geographic and seasonal distribution of Phlebotomus papatasi in Southwest Asia

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cross, E.R.; Hyams, K.C.

    1996-07-01

    The distribution of Phlebotomus papatasi in Southwest Asia is thought to be highly dependent on temperature and relative humidity. A discriminant analysis model based on weather data and reported vector surveys was developed to predict the seasonal and geographic distribution of P. papatasi in this region. To simulate global warming, temperature values for 115 weather stations were increased by 1 {degrees}C, 3{degrees}C, and 5{degrees}C, and the outcome variable coded as unknown in the model. Probability of occurrence values were then predicted for each location with a weather station. Stations with positive probability of occurrence values for May, June, July, andmore » August were considered locations where two or more life cycles of P. papatasi could occur and which could support endemic transmission of leishmaniasis and sandfly fever. Among 115 weather stations, 71 (62%) would be considered endemic with current temperature conditions; 14 (12%) additional station could become endemic with an increase of 1 {degrees}C; 17 (15%) more than a 3{degrees}C increase; and 12 (10%) more (all but one station) with a t{degrees}C increase. In addition to increased geographic distribution, seasonality of disease transmission could be extended throughout 12 months of the year in 7 (6%) locations with at least a 3{degrees}C rise in temperature and in 29 (25%) locations with a 5{degrees}C rise. 15 refs., 4 figs.« less

  1. Multi-century cool- and warm-season rainfall reconstructions for Australia's major climatic regions

    NASA Astrophysics Data System (ADS)

    Freund, Mandy; Henley, Benjamin J.; Karoly, David J.; Allen, Kathryn J.; Baker, Patrick J.

    2017-11-01

    Australian seasonal rainfall is strongly affected by large-scale ocean-atmosphere climate influences. In this study, we exploit the links between these precipitation influences, regional rainfall variations, and palaeoclimate proxies in the region to reconstruct Australian regional rainfall between four and eight centuries into the past. We use an extensive network of palaeoclimate records from the Southern Hemisphere to reconstruct cool (April-September) and warm (October-March) season rainfall in eight natural resource management (NRM) regions spanning the Australian continent. Our bi-seasonal rainfall reconstruction aligns well with independent early documentary sources and existing reconstructions. Critically, this reconstruction allows us, for the first time, to place recent observations at a bi-seasonal temporal resolution into a pre-instrumental context, across the entire continent of Australia. We find that recent 30- and 50-year trends towards wetter conditions in tropical northern Australia are highly unusual in the multi-century context of our reconstruction. Recent cool-season drying trends in parts of southern Australia are very unusual, although not unprecedented, across the multi-century context. We also use our reconstruction to investigate the spatial and temporal extent of historical drought events. Our reconstruction reveals that the spatial extent and duration of the Millennium Drought (1997-2009) appears either very much below average or unprecedented in southern Australia over at least the last 400 years. Our reconstruction identifies a number of severe droughts over the past several centuries that vary widely in their spatial footprint, highlighting the high degree of diversity in historical droughts across the Australian continent. We document distinct characteristics of major droughts in terms of their spatial extent, duration, intensity, and seasonality. Compared to the three largest droughts in the instrumental period (Federation Drought

  2. A cicada that ensures its fitness during climate warming by synchronizing its hatching time with the rainy season.

    PubMed

    Moriyama, Minoru; Numata, Hideharu

    2011-12-01

    A shift in phenology due to climate change is associated with some recent changes in populations, as it can disrupt the synchrony between organisms' requirements and resource availability. This conceptual framework has been developed mostly in systems of trophic interactions. Many coincidental changes, however, are involved in trophic interactions, preventing us from describing the direct impact of phenological shifts on fitness consequences. Here we address the phenological relationship in a simple non-trophic interaction to document a causal process of a warming-driven fitness change in a cicada, Cryptotympana facialis, whose numbers increased dramatically in Osaka, Japan in the late 20th century. We show that synchrony of the rainy season and hatching time may have a substantial influence on hatching success, by 1) shifting the time of completion of embryonic development, and 2) supplying water at various intervals. We estimate the change in hatching time over the last eleven decades (1901-2009) based on meteorological records and the temperature-dependent rate of C. facialis embryogenesis. Our estimate shows that hatching had initially occurred after the rainy season, and that warming had advanced it into the rainy season in the late 20th century. The probability of hatching success was markedly variable, and often very low before this synchronization occurred, but became stably high thereafter. Our findings suggest that the stabilizing effect of this synchrony on fitness was indispensable to the recent population increase of C. facialis.

  3. Curvularia malina sp. nov. incites a new disease of warm-season turfgrasses in the southeastern United States.

    PubMed

    Tomaso-Peterson, Maria; Jo, Young-Ki; Vines, Phillip L; Hoffmann, Federico G

    2016-09-01

    A novel species of Curvularia was identified as a foliar pathogen of Cynodon dactylon (bermudagrass) and Zoysia matrella (zoysiagrass), two important warm-season turfgrasses in the southeastern United States. Field symptoms were conspicuous chocolate brown to black spots in turf of both species on golf course putting greens and fairways. Leaves of plants within these spots exhibited prominent, black eyespot lesions from which a darkly pigmented fungus was consistently isolated. The fungus produced gray- to black-olivaceous mycelium within 10 d on potato dextrose agar at 25 C but never produced conidia despite numerous attempts to induce them. Field symptoms were reproduced in inoculated plants of both grasses, and re-isolation of the pathogen from symptomatic tissues confirmed its pathogenicity in fulfillment of Koch's postulates. A phylogenetic analysis was performed using sequence markers of internal nuclear ribosomal transcribed spacer region (ITS), glyceralde-hyde-3-phosphate dehydrogenase (GPD1) and translation elongation factor 1-α (TEF 1). The concatenated phylogenetic tree showed strong support for a new species within Curvularia that is distinctly divergent from other Curvularia spp. Therefore, the darkly pigmented pathogen of warm-season turfgrasses is described and illustrated as a new species, Curvularia malina. © 2016 by The Mycological Society of America.

  4. Amplified Arctic warming by phytoplankton under greenhouse warming.

    PubMed

    Park, Jong-Yeon; Kug, Jong-Seong; Bader, Jürgen; Rolph, Rebecca; Kwon, Minho

    2015-05-12

    Phytoplankton have attracted increasing attention in climate science due to their impacts on climate systems. A new generation of climate models can now provide estimates of future climate change, considering the biological feedbacks through the development of the coupled physical-ecosystem model. Here we present the geophysical impact of phytoplankton, which is often overlooked in future climate projections. A suite of future warming experiments using a fully coupled ocean-atmosphere model that interacts with a marine ecosystem model reveals that the future phytoplankton change influenced by greenhouse warming can amplify Arctic surface warming considerably. The warming-induced sea ice melting and the corresponding increase in shortwave radiation penetrating into the ocean both result in a longer phytoplankton growing season in the Arctic. In turn, the increase in Arctic phytoplankton warms the ocean surface layer through direct biological heating, triggering additional positive feedbacks in the Arctic, and consequently intensifying the Arctic warming further. Our results establish the presence of marine phytoplankton as an important potential driver of the future Arctic climate changes.

  5. Amplified Arctic warming by phytoplankton under greenhouse warming

    PubMed Central

    Park, Jong-Yeon; Kug, Jong-Seong; Bader, Jürgen; Rolph, Rebecca; Kwon, Minho

    2015-01-01

    Phytoplankton have attracted increasing attention in climate science due to their impacts on climate systems. A new generation of climate models can now provide estimates of future climate change, considering the biological feedbacks through the development of the coupled physical–ecosystem model. Here we present the geophysical impact of phytoplankton, which is often overlooked in future climate projections. A suite of future warming experiments using a fully coupled ocean−atmosphere model that interacts with a marine ecosystem model reveals that the future phytoplankton change influenced by greenhouse warming can amplify Arctic surface warming considerably. The warming-induced sea ice melting and the corresponding increase in shortwave radiation penetrating into the ocean both result in a longer phytoplankton growing season in the Arctic. In turn, the increase in Arctic phytoplankton warms the ocean surface layer through direct biological heating, triggering additional positive feedbacks in the Arctic, and consequently intensifying the Arctic warming further. Our results establish the presence of marine phytoplankton as an important potential driver of the future Arctic climate changes. PMID:25902494

  6. Root and Shoot Phenology May Respond Differently to Warming

    NASA Astrophysics Data System (ADS)

    Radville, L.; Eissenstat, D. M.; Post, E.

    2015-12-01

    Climate change is increasing temperatures and extending the growing season for many organisms. Shifts in phenology have been widely reported in response to global warming and have strong effects on ecosystem processes and greenhouse gas emissions. It is well understood that warming generally advances aboveground plant phenology, but the influence of temperature on root phenology is unclear. Most terrestrial biosphere models assume that root and shoot growth occur at the same time and are influenced by warming in the same way, but recent studies suggest that this may not be the case. Testing this assumption is particularly important in the Arctic where over 70% of plant biomass can be belowground and warming is happening faster than in other ecosystems. In 2013 and 2014 we examined the timing of root growth in the Arctic in plots that had been warmed or unwarmed for 10 years. We found that peak root growth occurred about one month before leaf growth, suggesting that spring root phenology is not controlled by carbon produced during spring photosynthesis. If root phenology is not controlled by photosynthate early in the season, earlier spring leaf growth may not cause earlier spring root growth. In support of this, we found that warming advanced spring leaf cover but did not significantly affect root phenology. Root growth was not significantly correlated with soil temperature and did not appear to be limited by near-freezing temperatures above the permafrost. These results suggest that although shoots are influenced by temperature, roots in this system may be more influenced by photosynthesis and carbon storage. Aboveground phenology, one of the most widely measured aspects of climate change, may not represent whole-plant phenology and may be a poor indicator of the timing of whole-plant carbon fluxes. Additionally, climate model assumptions that roots and shoots grow at the same time may need to be revised.

  7. How does the dengue vector mosquito Aedes albopictus respond to global warming?

    PubMed

    Jia, Pengfei; Chen, Xiang; Chen, Jin; Lu, Liang; Liu, Qiyong; Tan, Xiaoyue

    2017-03-11

    Global warming has a marked influence on the life cycle of epidemic vectors as well as their interactions with human beings. The Aedes albopictus mosquito as the vector of dengue fever surged exponentially in the last decade, raising ecological and epistemological concerns of how climate change altered its growth rate and population dynamics. As the global warming pattern is considerably uneven across four seasons, with a confirmed stronger effect in winter, an emerging need arises as to exploring how the seasonal warming effects influence the annual development of Ae. albopictus. The model consolidates a 35-year climate dataset and designs fifteen warming patterns that increase the temperature of selected seasons. Based on a recently developed mechanistic population model of Ae. albopictus, the model simulates the thermal reaction of blood-fed adults by systematically increasing the temperature from 0.5 to 5 °C at an interval of 0.5 °C in each warming pattern. The results show the warming effects are different across seasons. The warming effects in spring and winter facilitate the development of the species by shortening the diapause period. The warming effect in summer is primarily negative by inhibiting mosquito development. The warming effect in autumn is considerably mixed. However, these warming effects cannot carry over to the following year, possibly due to the fact that under the extreme weather in winter the mosquito fully ceases from development and survives in terms of diapause eggs. As the historical pattern of global warming manifests seasonal fluctuations, this study provides corroborating and previously ignored evidence of how such seasonality affects the mosquito development. Understanding this short-term temperature-driven mechanism as one chain of the transmission events is critical to refining the thermal reaction norms of the epidemic vector under global warming as well as developing effective mosquito prevention and control strategies.

  8. Observed seasonal and interannual variability of the near-surface thermal structure of the Arabian Sea Warm Pool

    NASA Astrophysics Data System (ADS)

    Rao, R. R.; Ramakrishna, S. S. V. S.

    2017-06-01

    The observed seasonal and interannual variability of near-surface thermal structure of the Arabian Sea Warm Pool (ASWP) is examined utilizing a reanalysis data set for the period 1990-2008. During a year, the ASWP progressively builds from February, reaches its peak by May only in the topmost 60 m water column. The ASWP Index showed a strong seasonal cycle with distinct interannual signatures. The years with higher (lower) sea surface temperature (SST) and larger (smaller) spatial extent are termed as strong (weak) ASWP years. The differences in the magnitude and spatial extent of thermal structure between the strong and weak ASWP regimes are seen more prominently in the topmost 40 m water column. The heat content values with respect to 28 °C isotherm (HC28) are relatively higher (lower) during strong (weak) ASWP years. Even the secondary peak in HC28 seen during the preceding November-December showed higher (lower) magnitude during the strong ASWP (weak) years. The influence of the observed variability in the surface wind field, surface net air-sea heat flux, near-surface mixed layer thickness, sea surface height (SSH) anomaly, depth of 20 °C isotherm and barrier layer thickness is examined to explain the observed differences in the near-surface thermal structure of the ASWP between strong and weak regimes. The surface wind speed is much weaker in particular during the preceding October and February-March corresponding to the strong ASWP years when compared to those of the weak ASWP years implying its important role. Both stronger winter cooling during weak ASWP years and stronger pre-monsoon heating during strong ASWP years through the surface air-sea heat fluxes contribute to the observed sharp contrast in the magnitudes of both the regimes of the ASWP. The upwelling Rossby wave during the preceding summer monsoon, post-monsoon and winter seasons is stronger corresponding to the weak ASWP regime when compared to the strong ASWP regime resulting in greater

  9. Seasonal patterns in soil N availability in the arctic tundra in response to accelerated snowmelt and warming

    NASA Astrophysics Data System (ADS)

    Darrouzet-Nardi, A.; Wallenstein, M. D.; Steltzer, H.; Sullivan, P.; Melle, C.; Segal, A.; Weintraub, M. N.

    2010-12-01

    Arctic soils contain large stocks of carbon (C) and may act as a significant CO2 source in response to climate warming. However, nitrogen (N) availability limits both plant growth and decomposition in many Arctic sites, and may thus be a key constraint on climate-carbon feedbacks. While current models of tundra ecosystems and their responses to climate change assume that N limits plant growth and C limits decomposition, there is strong evidence to the contrary showing that N can also limit decomposition. For example, the production of both new microbial biomass and enzymes that degrade organic matter appear to be limited by N during the summer. N availability is strongly seasonal: we have previously observed relatively high availability early in the growing season followed by a pronounced crash in tussock tundra soils. To investigate the drivers of N availability throughout the season, we used a field manipulation of tussock tundra growing season length (~4 days acceleration of snowmelt) and air temperature (open top chambers) and a laboratory soil N addition in both early and late season. Nutrient availability throughout the field season was measured at high temporal resolution (25 measurements from soil thaw through early plant senescence). Results from a laboratory experiment in which N was added to early season and late season soils suggests that soil respiration is in fact N limited at both times of the season, though this limitation is temperature dependent with effects most pronounced at 10°C. High-resolution measurements of nutrients in the soil solution and extractable N throughout the season showed that although a nutrient crash in N can be observed mid-season, N availability can still fluctuate later in the season. Finally, effects of the extended growing season and increased air temperature have so far had few effects on soil nutrient N dynamics throughout the summer growing season, suggesting either an insensitivity of N availability to these

  10. Global Warming Induced Changes in Rainfall Characteristics in IPCC AR5 Models

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.; Wu, Jenny, H.-T.; Kim, Kyu-Myong

    2012-01-01

    Changes in rainfall characteristic induced by global warming are examined from outputs of IPCC AR5 models. Different scenarios of climate warming including a high emissions scenario (RCP 8.5), a medium mitigation scenario (RCP 4.5), and 1% per year CO2 increase are compared to 20th century simulations (historical). Results show that even though the spatial distribution of monthly rainfall anomalies vary greatly among models, the ensemble mean from a sizable sample (about 10) of AR5 models show a robust signal attributable to GHG warming featuring a shift in the global rainfall probability distribution function (PDF) with significant increase (>100%) in very heavy rain, reduction (10-20% ) in moderate rain and increase in light to very light rains. Changes in extreme rainfall as a function of seasons and latitudes are also examined, and are similar to the non-seasonal stratified data, but with more specific spatial dependence. These results are consistent from TRMM and GPCP rainfall observations suggesting that extreme rainfall events are occurring more frequently with wet areas getting wetter and dry-area-getting drier in a GHG induced warmer climate.

  11. Achilles tendon structure improves on UTC imaging over a 5-month pre-season in elite Australian football players.

    PubMed

    Docking, S I; Rosengarten, S D; Cook, J

    2016-05-01

    Pre-season injuries are common and may be due to a reintroduction of training loads. Tendons are sensitive to changes in load, making them vulnerable to injury in the pre-season. This study investigated changes in Achilles tendon structure on ultrasound tissue characterization (UTC) over the course of a 5-month pre-season in elite male Australian football players. Eighteen elite male Australian football players with no history of Achilles tendinopathy and normal Achilles tendons were recruited. The left Achilles tendon was scanned with UTC to quantify the stability of the echopattern. Participants were scanned at the start and completion of a 5-month pre-season. Fifteen players remained asymptomatic over the course of the pre-season. All four echo-types were significantly different at the end of the pre-season, with the overall echopattern suggesting an improvement in Achilles tendon structure. Three of the 18 participants developed Achilles tendon pain that coincided with a change in the UTC echopattern. This study demonstrates that the UTC echopattern of the Achilles tendon improves over a 5-month pre-season training period, representing increased fibrillar alignment. However, further investigation is needed to elucidate with this alteration in the UTC echopattern results in improved tendon resilience and load capacity. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Ten-year variability in ecosystem water use efficiency in an oak-dominated temperate forest under a warming climate

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Xie, Jing; Chen, Jiquan; Sun, Ge

    The impacts of extreme weather events on water-carbon (C) coupling and ecosystem-scale water use efficiency (WUE) over a long term are poorly understood. We analyzed the changes in ecosystem water use efficiency (WUE) from 10 years of eddy-covariance measurements (2004-2013) over an oak-dominated temperate forest in Ohio, USA. The aim was to investigate the long-term response of ecosystem WUE to measured changes in site-biophysical conditions and ecosystem attributes. The oak forest produced new plant biomass of 2.5 +/- 0.2 gC kg(-1) of water loss annually. Monthly evapotranspiration (ET) and gross ecosystem production (GEP) were tightly coupled over the 10-year studymore » period (R-2=0.94). Daily WUE had a linear relationship with air temperature (T-a) in low-temperature months and a unimodal relationship with T-a in high-temperature months during the growing season. On average, daily WUE ceased to increase when T-a exceeded 22 degrees C in warm months for both wet and dry years. Monthly WUE had a strong positive linear relationship with leaf area index (LAI), net radiation (R-n), and T-a and weak logarithmic relationship with water vapor pressure deficit (VPD) and precipitation (P) on a growing-season basis. When exploring the regulatory mechanisms on WUE within each season, spring LAI and P, summer R-n and T-a, and autumnal VPD and R-n were found to be the main explanatory variables for seasonal variation in WUE. The model developed in this study was able to capture 78% of growing-season variation in WUE on a monthly basis. The negative correlation between WUE and A in spring was mainly due to the high precipitation amounts in spring, decreasing GEP and WUE when LAI was still small, adding ET being observed to increase with high levels of evaporation as a result of high SWC in spring. Summer WUE had a significant decreasing trend across the 10 years mainly due to the combined effect of seasonal drought and increasing potential and available energy increasing

  13. Ten-year variability in ecosystem water use efficiency in an oak-dominated temperate forest under a warming climate

    DOE PAGES

    Xie, Jing; Chen, Jiquan; Sun, Ge; ...

    2016-01-07

    The impacts of extreme weather events on water-carbon (C) coupling and ecosystem-scale water use efficiency (WUE) over a long term are poorly understood. We analyzed the changes in ecosystem water use efficiency (WUE) from 10 years of eddy-covariance measurements (2004-2013) over an oak-dominated temperate forest in Ohio, USA. The aim was to investigate the long-term response of ecosystem WUE to measured changes in site-biophysical conditions and ecosystem attributes. The oak forest produced new plant biomass of 2.5 +/- 0.2 gC kg(-1) of water loss annually. Monthly evapotranspiration (ET) and gross ecosystem production (GEP) were tightly coupled over the 10-year studymore » period (R-2=0.94). Daily WUE had a linear relationship with air temperature (T-a) in low-temperature months and a unimodal relationship with T-a in high-temperature months during the growing season. On average, daily WUE ceased to increase when T-a exceeded 22 degrees C in warm months for both wet and dry years. Monthly WUE had a strong positive linear relationship with leaf area index (LAI), net radiation (R-n), and T-a and weak logarithmic relationship with water vapor pressure deficit (VPD) and precipitation (P) on a growing-season basis. When exploring the regulatory mechanisms on WUE within each season, spring LAI and P, summer R-n and T-a, and autumnal VPD and R-n were found to be the main explanatory variables for seasonal variation in WUE. The model developed in this study was able to capture 78% of growing-season variation in WUE on a monthly basis. The negative correlation between WUE and A in spring was mainly due to the high precipitation amounts in spring, decreasing GEP and WUE when LAI was still small, adding ET being observed to increase with high levels of evaporation as a result of high SWC in spring. Summer WUE had a significant decreasing trend across the 10 years mainly due to the combined effect of seasonal drought and increasing potential and available energy increasing

  14. Incidence of Medically Attended Respiratory Syncytial Virus and Influenza Illnesses in Children 6-59 Months Old During Four Seasons.

    PubMed

    Simpson, Melissa D; Kieke, Burney A; Sundaram, Maria E; McClure, David L; Meece, Jennifer K; Sifakis, Frangiscos; Gasser, Robert A; Belongia, Edward A

    2016-04-01

    Background.  Respiratory syncytial virus (RSV) and influenza are significant causes of seasonal respiratory illness in children. The incidence of influenza and RSV hospitalization is well documented, but the incidence of medically attended, laboratory-confirmed illness has not been assessed in a well defined community cohort. Methods.  Children aged 6-59 months with medically attended acute respiratory illness were prospectively enrolled during the 2006-2007 through 2009-2010 influenza seasons in a Wisconsin community cohort. Nasal swabs were tested for RSV and influenza by multiplex reverse-transcription polymerase chain reaction. The population incidence of medically attended RSV and influenza was estimated separately and standardized to weeks 40 through 18 of each season. Results.  The cohort included 2800-3073 children each season. There were 2384 children enrolled with acute respiratory illness; 627 (26%) were positive for RSV and 314 (13%) for influenza. The mean age was 28 months (standard deviation [SD] = 15) for RSV-positive and 38 months (SD = 16) for influenza-positive children. Seasonal incidence (cases per 10 000) was 1718 (95% confidence interval [CI], 1602-1843) for RSV and 768 (95% CI, 696-848) for influenza. Respiratory syncytial virus incidence was highest among children 6-11 (2927) and 12-23 months old (2377). Influenza incidence was highest (850) in children 24-59 months old. The incidence of RSV was higher than influenza across all seasons and age groups. Conclusions.  The incidence of medically attended RSV was highest in children 6-23 months old, and it was consistently higher than influenza. The burden of RSV remains high throughout the first 2 years of life.

  15. Modelling Climate Change Impacts on the Seasonality of Water Resources in the Upper Ca River Watershed in Southeast Asia

    PubMed Central

    Giang, Pham Quy; Sakata, Masahiro; Vinh, Tran Quoc

    2014-01-01

    The impact of climate change on the seasonality of water resources in the Upper Ca River Watershed in mainland Southeast Asia was assessed using downscaled global climate models coupled with the SWAT model. The results indicated that temperature and evapotranspiration will increase in all months of future years. The area could warm as much as 3.4°C in the 2090s, with an increase of annual evapotranspiration of up to 23% in the same period. We found an increase in the seasonality of precipitation (both an increase in the wet season and a decrease in the dry season). The greatest monthly increase of up to 29% and the greatest monthly decrease of up to 30% are expected in the 2090s. As a result, decreases in dry season discharge and increases in wet season discharge are expected, with a span of ±25% for the highest monthly changes in the 2090s. This is expected to exacerbate the problem of seasonally uneven distribution of water resources: a large volume of water in the wet season and a scarcity of water in the dry season, a pattern that indicates the possibility of more frequent floods in the wet season and droughts in the dry season. PMID:25243206

  16. A Digital Map From External Forcing to the Final Surface Warming Pattern and its Seasonal Cycle

    NASA Astrophysics Data System (ADS)

    Cai, M.

    2015-12-01

    Historically, only the thermodynamic processes (e.g., water vapor, cloud, surface albedo, and atmospheric lapse rate) that directly influence the top of the atmosphere (TOA) radiative energy flux balance are considered in climate feedback analysis. One of my recent research areas is to develop a new framework for climate feedback analysis that explicitly takes into consideration not only the thermodynamic processes that the directly influence the TOA radiative energy flux balance but also the local dynamical (e.g., evaporation, surface sensible heat flux, vertical convections etc) and non-local dynamical (large-scale horizontal energy transport) processes in aiming to explain the warming asymmetry between high and low latitudes, between ocean and land, and between the surface and atmosphere. In the last 5-6 years, we have developed a coupled atmosphere-surface climate feedback-response analysis method (CFRAM) as a new framework for estimating climate feedback and sensitivity in coupled general circulation models with a full physical parameterization package. In the CFRAM, the isolation of partial temperature changes due to an external forcing alone or an individual feedback is achieved by solving the linearized infrared radiation transfer model subject to individual energy flux perturbations (external or due to feedbacks). The partial temperature changes are addable and their sum is equal to the (total) temperature change (in the linear sense). The CFRAM is used to isolate the partial temperature changes due to the external forcing, due to water vapor feedback, clouds, surface albedo, local vertical convection, and non-local atmospheric dynamical feedbacks, as well as oceanic heat storage. It has been shown that seasonal variations in the cloud feedback, surface albedo feedback, and ocean heat storage/dynamics feedback, directly caused by the strong annual cycle of insolation, contribute primarily to the large seasonal variation of polar warming. Furthermore, the

  17. Cloud-to-ground lightning and surface rainfall in warm-season Florida thunderstorms

    USGS Publications Warehouse

    Gungle, B.; Krider, E.P.

    2006-01-01

    Relationships between cloud-to-ground (CG) lightning and surface rainfall have been examined in nine isolated, warm-season thunderstorms on the east coast of central Florida. CG flashes and the associated rain volumes were measured as a function of time in storm-centered reference frames that followed each storm over a network of rain gauges. Values of the storm-average rain volume per CG flash ranged from 0.70 ?? 104 to 6.4 ?? 104 m3/CG flash, with a mean (and standard deviation) of 2.6 ?? 104 ?? 2.1 ?? 104 m3/CG flash. Values of the rain volume concurrent with CG flashes ranged from 0.11 ?? 104 to 4.9 ?? 104 m3/CG flash with a mean of 2.1 ?? 104 ?? 2.0 ?? 104 m3/CG flash. The lag-time between the peak CG flash rate and the peak rainfall rate (using 5 min bins), and the results of a lag correlation analysis, show that surface rainfall tends to follow the lightning (positive lag) by up to 20 min in six storms. In one storm the rainfall preceded the lightning by 5 min, and two storms had nonsignificant lags. Values of the lagged rain volume concurrent with CG flashes ranged from 0.43 ?? 104 to 4.9 ?? 104 m3/CG flash, and the mean was 1.9 ?? 104 ?? 1.7 ?? 104 m3/CG flash. For the five storms that produced 12 or more flashes and had significant lags, a plot of the optimum lag time versus the total number of CG flashes shows a linear trend (R2 = 0.56). The number of storms is limited, but the lag results do indicate that large storms tend to have longer lags. A linear fit to the lagged rain volume vs. the number of concurrent CG flashes has a slope of 1.9 ?? 104 m3/CG flash (R2 = 0.83). We conclude that warm-season Florida thunderstorms produce a roughly constant rain volume per CG flash and that CG lightning can be used to estimate the location and intensity of convective rainfall in that weather regime. Copyright 2006 by the American Geophysical Union.

  18. Mechanisms of elevation-dependent warming over complex terrain in high-resolution simulations of regional climate change

    NASA Astrophysics Data System (ADS)

    Minder, J. R.; Letcher, T.; Liu, C.

    2016-12-01

    Numerous observational and modeling studies have suggested that over mountainous terrain certain elevations can experience systematically enhanced rates of near-surface climate warming relative to the surrounding region, a phenomenon referred to as elevation-dependent warming (EDW). In many of these studies high-elevation locations were found to experience the fastest warming rates. A variety of physical mechanisms for EDW have been proposed but there is no consensus as to the dominant cause. We examine EDW in regional climate model (RCM) simulations with very high horizontal resolution (4-km horizontal grid). The simulation domain centers on the Rocky Mountains and intermountain west of the United States. Climate change simulations are conducted using the "pseudo global warming" framework to focus on the regional response to large-scale thermodynamic and radiative climate changes representative of mid-century anthropogenic global climate change. Substantial EDW is found in these simulations. Warming varies with elevation by up to 1°C depending on the season considered. The structure of EDW is only weakly sensitive to variations in horizontal grid spacing ranging from 4 to 36 km. The snow-albedo feedback (SAF) plays a major role in causing the simulated EDW. The elevation band of maximum warming varies seasonally, mostly following the margin of the seasonal snowpack where snow cover and albedo reductions are maximized under climate warming. Additional simulations where the SAF is artificially suppressed demonstrate that EDW variations of up to 0.6°C can be attributed to the SAF. Simulations with a suppressed SAF still exhibit EDW variations up to 0.8°C that must be explained by other mechanisms. This remaining EDW shows a near linear increase in warming with elevation in most months and does not appear to be inherited from the profile of large-scale free-tropospheric warming. Simple theoretical calculations suggest that the non-linear dependence of surface

  19. On the Seasonality of Sudden Stratospheric Warmings

    NASA Astrophysics Data System (ADS)

    Reichler, T.; Horan, M.

    2017-12-01

    The downward influence of sudden stratospheric warmings (SSWs) creates significant tropospheric circulation anomalies that last for weeks. It is therefore of theoretical and practical interest to understand the time when SSWs are most likely to occur and the controlling factors for the temporal distribution of SSWs. Conceivably, the distribution between mid-winter and late-winter is controlled by the interplay between decreasing eddy convergence in the region of the polar vortex and the weakening strength of the polar vortex. General circulation models (GCMs) tend to produce SSW maxima later in winter than observations, which has been considered as a model deficiency. However, the observed record is short, suggesting that under-sampling of SSWs may contribute to this discrepancy. Here, we study the climatological frequency distribution of SSWs and related events in a long control simulation with a stratosphere resolving GCM. We also create a simple statistical model to determine the primary factors controlling the SSW distribution. The statistical model is based on the daily climatological mean, standard deviation, and autocorrelation of stratospheric winds, and assumes that the winds follow a normal distribution. We find that the null hypothesis, that model and observations stem from the same distribution, cannot be rejected, suggesting that the mid-winter SSW maximum seen in the observations is due to sampling uncertainty. We also find that the statistical model faithfully reproduces the seasonal distribution of SSWs, and that the decreasing climatological strength of the polar vortex is the primary factor for it. We conclude that the late-winter SSW maximum seen in most models is realistic and that late events will be more prominent in future observations. We further conclude that SSWs simply form the tail of normally distributed stratospheric winds, suggesting that there is a continuum of weak polar vortex states and that statistically there is nothing special

  20. [Seasonality of rotavirus infection in Venezuela: relationship between monthly rotavirus incidence and rainfall rates].

    PubMed

    González Chávez, Rosabel

    2015-09-01

    In general, it has been reported that rotavirus infection was detected year round in tropical countries. However, studies in Venezuela and Brazil suggest a seasonal behavior of the infection. On the other hand, some studies link infection with climatic variables such as rainfall. This study analyzes the pattern of behavior of the rotavirus infection in Carabobo-Venezuela (2001-2005), associates the seasonality of the infection with rainfall, and according to the seasonal pattern, estimates the age of greatest risk for infection. The analysis of the rotavirus temporal series and accumulated precipitation was performed with the software SPSS. The infection showed two periods: high incidence (November-April) and low incidence (May-October). Accumulated precipitation presents an opposite behavior. The highest frequency of events (73.8% 573/779) for those born in the period with a low incidence of the virus was recorded at an earlier age (mean age 6.5 +/- 2.0 months) when compared with those born in the station of high incidence (63.5% 568/870, mean age 11.7 +/- 2.2 months). Seasonality of the infection and the inverse relationship between virus incidence and rainfall was demonstrated. In addition, it was found that the period of birth determines the age and risk of infection. This information generated during the preaccine period will be helpful to measure the impact of the vaccine against the rotavirus.

  1. Assessing Climate Change Impacts for Military Installations in the Southwest United States During the Warm Season

    NASA Astrophysics Data System (ADS)

    Castro, C.

    2013-05-01

    Arid and semi-arid regions are experiencing some of the most adverse impacts of climate change with increased heat waves, droughts, and extreme weather. These events will likely exacerbate socioeconomic and political instabilities in regions where the United States has vital strategic interests and ongoing military operations. The Southwest U.S. is strategically important in that it houses some of the most spatially expansive and important military installations in the country. The majority of severe weather events in the Southwest occur in association with the North American monsoon system (NAMS), and current observational record has shown a 'wet gets wetter and dry gets drier' global monsoon precipitation trend. We seek to evaluate the warm season extreme weather projection in the Southwest U.S., and how the extremes can affect Department of Defense (DoD) military facilities in that region. A baseline methodology is being developed to select extreme warm season weather events based on historical sounding data and moisture surge observations from Gulf of California. Numerical Weather Prediction (NWP)-type high resolution simulations will be performed for the extreme events identified from Weather Research and Forecast (WRF) model simulations initiated from IPCC GCM and NCAR Reanalysis data in both climate control and climate change periods. The magnitude in extreme event changes will be analyzed, and the synoptic forcing patterns of the future severe thunderstorms will provide a guide line to assess if the military installations in the Southwest will become more or less susceptible to severe weather in the future.

  2. Cool seasons are related to poor prognosis in patients with infective endocarditis

    NASA Astrophysics Data System (ADS)

    Chen, Su-Jung; Chao, Tze-Fan; Lin, Yenn-Jiang; Lo, Li-Wei; Hu, Yu-Feng; Tuan, Ta-Chuan; Hsu, Tsui-Lieh; Yu, Wen-Chung; Leu, Hsin-Bang; Chang, Shih-Lin; Chen, Shih-Ann

    2012-09-01

    Many cardiac diseases demonstrate seasonal variations in the incidence and mortality. This study was designed to investigate whether the mortality of infective endocarditis (IE) was higher in cool seasons and to evaluate the effects of cool climate for IE. We enrolled 100 IE patients with vegetations in our hospital. The temperatures of the IE episodes were defined as the monthly average temperatures of the admission days. The average temperatures in the cool (fall/winter) and warm seasons (spring/summer) were 19.2°C and 27.6°C, respectively. In addition, patients admitted with the diagnosis of IE were identified from the National Health Insurance Research Database (NHIRD) and the in-hospital mortality rates in cool and warm seasons were compared to validate the findings derived from the data of our hospital. The mortality rate for IE was significantly higher in fall/winter than in spring/summer which presents consistently in the patient population of our hospital (32.7% versus 12.5%, p = 0.017) and from NHIRD (10.4% versus 4.6%, p = 0.019). IE episodes which occurred during cool seasons presented with a higher rate of heart failure (44.2% versus 22.9%, p = 0.025) and D-dimer level (5.5 ± 3.8 versus 2.4 ± 1.8 μg/ml, p = 0.017) at admission than that of warm seasons. These results may reflect the impact of temperatures during the pre-hospitalized period on the disease process. In the multivariate analysis, Staphylococcal infection, left ventricular hypertrophy, left ventricular systolic dysfunction and temperature were the independent predictors of mortalities in IE patients.

  3. Plant phenological responses to a long-term experimental extension of growing season and soil warming in the tussock tundra of Alaska.

    PubMed

    Khorsand Rosa, Roxaneh; Oberbauer, Steven F; Starr, Gregory; Parker La Puma, Inga; Pop, Eric; Ahlquist, Lorraine; Baldwin, Tracey

    2015-12-01

    Climate warming is strongly altering the timing of season initiation and season length in the Arctic. Phenological activities are among the most sensitive plant responses to climate change and have important effects at all levels within the ecosystem. We tested the effects of two experimental treatments, extended growing season via snow removal and extended growing season combined with soil warming, on plant phenology in tussock tundra in Alaska from 1995 through 2003. We specifically monitored the responses of eight species, representing four growth forms: (i) graminoids (Carex bigellowii and Eriophorum vaginatum); (ii) evergreen shrubs (Ledum palustre, Cassiope tetragona, and Vaccinium vitis-idaea); (iii) deciduous shrubs (Betula nana and Salix pulchra); and (iv) forbs (Polygonum bistorta). Our study answered three questions: (i) Do experimental treatments affect the timing of leaf bud break, flowering, and leaf senescence? (ii) Are responses to treatments species-specific and growth form-specific? and (iii) Which environmental factors best predict timing of phenophases? Treatment significantly affected the timing of all three phenophases, although the two experimental treatments did not differ from each other. While phenological events began earlier in the experimental plots relative to the controls, duration of phenophases did not increase. The evergreen shrub, Cassiope tetragona, did not respond to either experimental treatment. While the other species did respond to experimental treatments, the total active period for these species did not increase relative to the control. Air temperature was consistently the best predictor of phenology. Our results imply that some evergreen shrubs (i.e., C. tetragona) will not capitalize on earlier favorable growing conditions, putting them at a competitive disadvantage relative to phenotypically plastic deciduous shrubs. Our findings also suggest that an early onset of the growing season as a result of decreased snow cover

  4. Weather Research and Forecasting Model Sensitivity Comparisons for Warm Season Convective Initiation

    NASA Technical Reports Server (NTRS)

    Watson, Leela R.; Hoeth, Brian; Blottman, Peter F.

    2007-01-01

    options within each core, provides SMG and NWS MLB with a lot of flexibility. It also creates challenges, such as determining which configuration options are best to address specific forecast concerns. The goal of this project is to assess the different configurations available and to determine which configuration will best predict warm season convective initiation in East-Central Florida. Four different combinations of WRF initializations will be run (ADAS-ARW, ADAS-NMM, LAPS-ARW, and LAPS-NMM) at a 4-km resolution over the Florida peninsula and adjacent coastal waters. Five candidate convective initiation days using three different flow regimes over East-Central Florida will be examined, as well as two null cases (non-convection days). Each model run will be integrated 12 hours with three runs per day, at 0900, 1200, and 1500 UTe. ADAS analyses will be generated every 30 minutes using Level II Weather Surveillance Radar-1988 Doppler (WSR-88D) data from all Florida radars to verify the convection forecast. These analyses will be run on the same domain as the four model configurations. To quantify model performance, model output will be subjectively compared to the ADAS analyses of convection to determine forecast accuracy. In addition, a subjective comparison of the performance of the ARW using a high-resolution local grid with 2-way nesting, I-way nesting, and no nesting will be made for select convective initiation cases. The inner grid will cover the East-Central Florida region at a resolution of 1.33 km. The authors will summarize the relative skill of the various WRF configurations and how each configuration behaves relative to the others, as well as determine the best model configuration for predicting warm season convective initiation over East-Central Florida.

  5. Phenological responses of Icelandic subarctic grasslands to short-term and long-term natural soil warming.

    PubMed

    Leblans, Niki I W; Sigurdsson, Bjarni D; Vicca, Sara; Fu, Yongshuo; Penuelas, Josep; Janssens, Ivan A

    2017-11-01

    The phenology of vegetation, particularly the length of the growing season (LOS; i.e., the period from greenup to senescence), is highly sensitive to climate change, which could imply potent feedbacks to the climate system, for example, by altering the ecosystem carbon (C) balance. In recent decades, the largest extensions of LOS have been reported at high northern latitudes, but further warming-induced LOS extensions may be constrained by too short photoperiod or unfulfilled chilling requirements. Here, we studied subarctic grasslands, which cover a vast area and contain large C stocks, but for which LOS changes under further warming are highly uncertain. We measured LOS extensions of Icelandic subarctic grasslands along natural geothermal soil warming gradients of different age (short term, where the measurements started after 5 years of warming and long term, i.e., warmed since ≥50 years) using ground-level measurements of normalized difference vegetation index. We found that LOS linearly extended with on average 2.1 days per °C soil warming up to the highest soil warming levels (ca. +10°C) and that LOS had the potential to extend at least 1 month. This indicates that the warming impact on LOS in these subarctic grasslands will likely not saturate in the near future. A similar response to short- and long-term warming indicated a strong physiological control of the phenological response of the subarctic grasslands to warming and suggested that genetic adaptations and community changes were likely of minor importance. We conclude that the warming-driven extension of the LOSs of these subarctic grasslands did not saturate up to +10°C warming, and hence that growing seasons of high-latitude grasslands are likely to continue lengthening with future warming (unless genetic adaptations or species shifts do occur). This persistence of the warming-induced extension of LOS has important implications for the C-sink potential of subarctic grasslands under climate

  6. Seasonal hydrologic responses to climate change in the Pacific Northwest

    NASA Astrophysics Data System (ADS)

    Vano, Julie A.; Nijssen, Bart; Lettenmaier, Dennis P.

    2015-04-01

    Increased temperatures and changes in precipitation will result in fundamental changes in the seasonal distribution of streamflow in the Pacific Northwest and will have serious implications for water resources management. To better understand local impacts of regional climate change, we conducted model experiments to determine hydrologic sensitivities of annual, seasonal, and monthly runoff to imposed annual and seasonal changes in precipitation and temperature. We used the Variable Infiltration Capacity (VIC) land-surface hydrology model applied at 1/16° latitude-longitude spatial resolution over the Pacific Northwest (PNW), a scale sufficient to support analyses at the hydrologic unit code eight (HUC-8) basin level. These experiments resolve the spatial character of the sensitivity of future water supply to precipitation and temperature changes by identifying the seasons and locations where climate change will have the biggest impact on runoff. The PNW exhibited a diversity of responses, where transitional (intermediate elevation) watersheds experience the greatest seasonal shifts in runoff in response to cool season warming. We also developed a methodology that uses these hydrologic sensitivities as basin-specific transfer functions to estimate future changes in long-term mean monthly hydrographs directly from climate model output of precipitation and temperature. When principles of linearity and superposition apply, these transfer functions can provide feasible first-order estimates of the likely nature of future seasonal streamflow change without performing downscaling and detailed model simulations.

  7. Seasonal movements, migratory behavior, and site fidelity of West Indian manatees along the Atlantic coast of the United States

    USGS Publications Warehouse

    Deutsch, C.J.; Reid, J.P.; Bonde, R.K.; Easton, Dean E.; Kochman, H.I.; O'Shea, T.J.

    2003-01-01

    The West Indian manatee (Trichechus manatus) is endangered by human activities throughout its range, including the U.S. Atlantic coast where habitat degradation from coastal development and manatee deaths from watercraft collisions have been particularly severe. We radio-tagged and tracked 78 manatees along the east coast of Florida and Georgia over a 12-year period (1986-1998). Our goals were to characterize the seasonal movements, migratory behavior, and site fidelity of manatees in this region in order to provide information for the development of effective conservation strategies. Most study animals were tracked remotely with the Argos satellite system, which yielded a mean (SD) of 3.7 (1.6) locations per day; all were regularly tracked in the field using conventional radiotelemetry methods. The combined data collection effort yielded >93,000 locations over nearly 32,000 tag-days. The median duration of tracking was 8.3 months per individual, but numerous manatees were tracked over multiple years (max = 6.8 years). Most manatees migrated seasonally over large distances between a northerly warm-season range and a southerly winter range (median one-way distance = 280 km, max = 830 km), but 12% of individuals were resident in a relatively small area (2,300 km of coastline between southeastern Florida and Rhode Island. No study animals journeyed to the Gulf coast of Florida. Regions heavily utilized by tagged manatees included: Fernandina Beach, FL to Brunswick, GA in the warm season; northern Biscayne Bay to Port Everglades, FL in the winter; and central coastal Florida, especially the Banana River and northern Indian River lagoons, in all seasons. Daily travel rate, defined as the distance between successive mean daily locations, averaged 2.5 km (SD = 1.7), but this varied with season, migratory pattern, and sex. Adult males traveled a significantly greater distance per day than did adult females for most of the warm season, which corresponded closely with the

  8. Sphagnum-dwelling testate amoebae in subarctic bogs are more sensitive to soil warming in the growing season than in winter: the results of eight-year field climate manipulations.

    PubMed

    Tsyganov, Andrey N; Aerts, Rien; Nijs, Ivan; Cornelissen, Johannes H C; Beyens, Louis

    2012-05-01

    Sphagnum-dwelling testate amoebae are widely used in paleoclimate reconstructions as a proxy for climate-induced changes in bogs. However, the sensitivity of proxies to seasonal climate components is an important issue when interpreting proxy records. Here, we studied the effects of summer warming, winter snow addition solely and winter snow addition together with spring warming on testate amoeba assemblages after eight years of experimental field climate manipulations. All manipulations were accomplished using open top chambers in a dry blanket bog located in the sub-Arctic (Abisko, Sweden). We estimated sensitivity of abundance, diversity and assemblage structure of living and empty shell assemblages of testate amoebae in the living and decaying layers of Sphagnum. Our results show that, in a sub-arctic climate, testate amoebae are more sensitive to climate changes in the growing season than in winter. Summer warming reduced species richness and shifted assemblage composition towards predominance of xerophilous species for the living and empty shell assemblages in both layers. The higher soil temperatures during the growing season also decreased abundance of empty shells in both layers hinting at a possible increase in their decomposition rates. Thus, although possible effects of climate changes on preservation of empty shells should always be taken into account, species diversity and structure of testate amoeba assemblages in dry subarctic bogs are sensitive proxies for climatic changes during the growing season. Copyright © 2011 Elsevier GmbH. All rights reserved.

  9. The Influence of Recurrent Modes of Climate Variability on the Occurrence of Monthly Temperature Extremes Over South America

    NASA Astrophysics Data System (ADS)

    Loikith, Paul C.; Detzer, Judah; Mechoso, Carlos R.; Lee, Huikyo; Barkhordarian, Armineh

    2017-10-01

    The associations between extreme temperature months and four prominent modes of recurrent climate variability are examined over South America. Associations are computed as the percent of extreme temperature months concurrent with the upper and lower quartiles of the El Niño-Southern Oscillation (ENSO), the Atlantic Niño, the Pacific Decadal Oscillation (PDO), and the Southern Annular Mode (SAM) index distributions, stratified by season. The relationship is strongest for ENSO, with nearly every extreme temperature month concurrent with the upper or lower quartiles of its distribution in portions of northwestern South America during some seasons. The likelihood of extreme warm temperatures is enhanced over parts of northern South America when the Atlantic Niño index is in the upper quartile, while cold extremes are often association with the lowest quartile. Concurrent precipitation anomalies may contribute to these relations. The PDO shows weak associations during December, January, and February, while in June, July, and August its relationship with extreme warm temperatures closely matches that of ENSO. This may be due to the positive relationship between the PDO and ENSO, rather than the PDO acting as an independent physical mechanism. Over Patagonia, the SAM is highly influential during spring and fall, with warm and cold extremes being associated with positive and negative phases of the SAM, respectively. Composites of sea level pressure anomalies for extreme temperature months over Patagonia suggest an important role of local synoptic scale weather variability in addition to a favorable SAM for the occurrence of these extremes.

  10. Beneficial effects of warmed humidified oxygen combined with nebulized albuterol and ipratropium in pediatric patients with acute exacerbation of asthma in winter months.

    PubMed

    Nibhanipudi, Kumara; Hassen, Getaw Worku; Smith, Arthur

    2009-11-01

    The objective of this study was to determine whether a combination of nebulized albuterol and ipratropium with warmed humidified oxygen would be more beneficial when compared to the same combination with humidified oxygen at room temperature. Albuterol alone was tested in the same settings. All patients between 6 and 17 years of age who presented to a pediatric emergency department in the winter months with acute exacerbation of bronchial asthma were given a combination of nebulized albuterol and ipratropium with warmed or room temperature humidified oxygen. Peak flow was measured before and after the treatment. Sixty patients were enrolled in the study, with 15 subjects in each group. The mean increase in peak flow in the albuterol-ipratropium with warm humidified oxygen group was 52.6, and in the albuterol-ipratropium with humidified oxygen at room temperature group, it was 26.2. The results of the albuterol with warmed humidified oxygen and with humidified oxygen at room temperature groups were 20.6 and 34.3, respectively. The differences between the groups were statistically significant. Our study shows that warmed humidified oxygen given along with the combination of nebulized albuterol and ipratropium is more beneficial for pediatric patients having an acute exacerbation of bronchial asthma in the winter months when compared to nebulized albuterol alone with warmed humidified oxygen, nebulized albuterol alone with room temperature humidified oxygen, or a combination of nebulized albuterol and ipratropium with room temperature humidified oxygen.

  11. Seasonal Flows in Palikir Crater

    NASA Image and Video Library

    2013-05-15

    Seasonal flows on warm Martian slopes may be caused by the flow of salty water on Mars, active today when the surface is warm above the freezing point of the solution. This observation is from NASA Mars Reconnaissance Orbiter.

  12. Development of a monthly to seasonal forecast framework tailored to inland waterway transport in central Europe

    NASA Astrophysics Data System (ADS)

    Meißner, Dennis; Klein, Bastian; Ionita, Monica

    2017-12-01

    Traditionally, navigation-related forecasts in central Europe cover short- to medium-range lead times linked to the travel times of vessels to pass the main waterway bottlenecks leaving the loading ports. Without doubt, this aspect is still essential for navigational users, but in light of the growing political intention to use the free capacity of the inland waterway transport in Europe, additional lead time supporting strategic decisions is more and more in demand. However, no such predictions offering extended lead times of several weeks up to several months currently exist for considerable parts of the European waterway network. This paper describes the set-up of a monthly to seasonal forecasting system for the German stretches of the international waterways of the Rhine, Danube and Elbe rivers. Two competitive forecast approaches have been implemented: the dynamical set-up forces a hydrological model with post-processed outputs from ECMWF general circulation model System 4, whereas the statistical approach is based on the empirical relationship (teleconnection) of global oceanic, climate and regional hydro-meteorological data with river flows. The performance of both forecast methods is evaluated in relation to the climatological forecast (ensemble of historical streamflow) and the well-known ensemble streamflow prediction approach (ESP, ensemble based on historical meteorology) using common performance indicators (correlation coefficient; mean absolute error, skill score; mean squared error, skill score; and continuous ranked probability, skill score) and an impact-based evaluation quantifying the potential economic gain. The following four key findings result from this study: (1) as former studies for other regions of central Europe indicate, the accuracy and/or skill of the meteorological forcing used has a larger effect than the quality of initial hydrological conditions for relevant stations along the German waterways. (2) Despite the predictive

  13. Warming slowdown over the Tibetan plateau in recent decades

    NASA Astrophysics Data System (ADS)

    Liu, Yaojie; Zhang, Yangjian; Zhu, Juntao; Huang, Ke; Zu, Jiaxing; Chen, Ning; Cong, Nan; Stegehuis, Annemiek Irene

    2018-03-01

    As the recent global warming hiatus and the warming on high elevations are attracting worldwide attention, this study examined the robustness of the warming slowdown over the Tibetan plateau (TP) and its related driving forces. By integrating multiple-source data from 1982 to 2015 and using trend analysis, we found that the mean temperature (T mean), maximum temperature (T max) and minimum temperature (T min) showed a slowdown of the warming trend around 1998, during the period of the global warming hiatus. This was found over both the growing season (GS) and non-growing season (NGS) and suggested a robust warming hiatus over the TP. Due to the differences in trends of T max and T min, the trend of diurnal temperature range (DTR) also shifted after 1998, especially during the GS temperature. The warming rate was spatially heterogeneous. The northern TP (NTP) experienced more warming than the southern TP (STP) in all seasons from 1982 to 1998, while the pattern was reversed in the period from 1998 to 2015. Water vapour was found to be the main driving force for the trend in T mean and T min by influencing downward long wave radiation. Sunshine duration was the main driving force behind the trend in T max and DTR through a change in downward shortwave radiation that altered the energy source of daytime temperature. Water vapour was the major driving force for temperature change over the NTP, while over the STP, sunshine duration dominated the temperature trend.

  14. Decadal Variation of the Number of El Nino Onsets and El Nino-Related Months and Estimating the Likelihood of El Nino Onset in a Warming World

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    2009-01-01

    Examination of the decadal variation of the number of El Nino onsets and El Nino-related months for the interval 1950-2008 clearly shows that the variation is better explained as one expressing normal fluctuation and not one related to global warming. Comparison of the recurrence periods for El Nino onsets against event durations for moderate/strong El Nino events results in a statistically important relationship that allows for the possible prediction of the onset for the next anticipated El Nino event. Because the last known El Nino was a moderate event of short duration (6 months), having onset in August 2006, unless it is a statistical outlier, one expects the next onset of El Nino probably in the latter half of 2009, with peak following in November 2009-January 2010. If true, then initial early extended forecasts of frequencies of tropical cyclones for the 2009 North Atlantic basin hurricane season probably should be revised slightly downward from near average-to-above average numbers to near average-to-below average numbers of tropical cyclones in 2009, especially as compared to averages since 1995, the beginning of the current high-activity interval for tropical cyclone activity.

  15. Dynamics behind warming of the southeastern Arabian Sea and its interruption based on in situ measurements

    NASA Astrophysics Data System (ADS)

    Mathew, Simi; Natesan, Usha; Latha, Ganesan; Venkatesan, Ramasamy

    2018-05-01

    A study of the inter-annual variability of the warming of the southeastern Arabian Sea (SEAS) during the spring transition months was carried out from 2013 to 2015 based on in situ data from moored buoys. An attempt was made to identify the roles of the different variables in the warming of the SEAS (e.g., net heat flux, advection, entrainment, and thickness of the barrier layer during the previous northeast monsoon season). The intense freshening of the SEAS (approximately 2 PSU) occurring in each December, together with the presence of a downwelling Rossby wave, supports the formation of a thick barrier layer during the northeast monsoon season. It is known that the barrier layer thickness, varying each year, plays a major role in the spring warming of the SEAS. Interestingly, an anomalously thick barrier layer occurred during the northeast monsoon season of 2012-2013. However, the highest sea surface temperature (31 °C) was recorded during the last week of April 2015, while the lowest sea surface temperature (29.7 °C) was recorded during the last week of May 2013. The mixed layer heat budget analysis during the spring transition months proved that the intense warming has been mainly supported by the net heat flux, not by other factors like advection and entrainment. The inter-annual variability analysis of the net heat flux and its components, averaged over a box region of the SEAS, showed a substantial latent heat flux release and a reduction in net shortwave radiation in 2013. Both factors contributed to the negative net heat flux. Strong breaks in the warming were also observed in May due to the entrainment of cold sub-surface waters. These events are associated with the cyclonic eddy persisting over the SEAS during the same time. The entrainment term, favoring the cooling, was stronger in 2015 than that in 2013 and 2014. The surface temperatures measured in 2013 were lower than those in 2014 and 2015 despite the presence of a thick barrier layer. The

  16. Europe experienced a "warming hole" in autumn in the second half of the 20th century

    NASA Astrophysics Data System (ADS)

    Cahynova, M.; Pokorna, L.; Huth, R.

    2012-12-01

    Recent global warming has not been ubiquitous - there might be seasons, regions, and time periods with clearly discernible zero or downward air temperature trends. Regions that are not warming or are even cooling - also known as "warming holes" - have been previously detected mainly in autumn in the second half of the 20th century in large parts of North America as well as in central and eastern Europe. In this study we use daily maximum and minimum temperature (TX and TN, respectively) and daily temperature range (DTR) at 136 stations from the ECA&D database in Europe and the Mediterranean in the period 1961-2000 to precisely locate their seasonal and sub-seasonal trends in space and within the course of the year, and to assess the effect of circulation changes on these observed trends. Linear trends are calculated for moving "seasons" of differing lengths (10, 20, 30, 60, and 90 days), each shifted by one day. Thus we obtain 365 values of "moving trends" for each station and each variant of season length. The day-to-day variability of these trends is greatest for short "seasons" of 10 and 20 days. Trends of the 90-day seasons are the most stable throughout the year and also bear the lowest trend magnitudes. Cluster analysis of the annual course of "moving trends" reveals relatively well-defined regions with similar trend behavior. Over most of Europe, the observed warming is greatest in winter, and the highest trend magnitudes are reached by TN in eastern Europe. Two regions stand out of this general picture: in Iceland and the Mediterranean, winter shows almost no trends, while in summer we see a pronounced warming. Significant autumn cooling centered on mid-November was found in eastern and southeastern Europe for both TX and TN; in many other regions trends are close to zero in the same period. Other clearly non-warming (or even cooling) periods occur in western and central Europe in April and June. Trends of DTR are largely inconclusive and no general picture

  17. Effects of seasonal change and experimental warming on the temperature dependence of photosynthesis in the canopy leaves of Quercus serrata.

    PubMed

    Yamaguchi, Daisuke P; Nakaji, Tatsuro; Hiura, Tsutom; Hikosaka, Kouki

    2016-10-01

    The effects of warming on the temperature response of leaf photosynthesis have become an area of major concern in recent decades. Although growth temperature (GT) and day length (DL) affect leaf gas exchange characteristics, the way in which these factors influence the temperature dependence of photosynthesis remains uncertain. We established open-top canopy chambers at the canopy top of a deciduous forest, in which average daytime leaf temperature was increased by 1.0 °C. We conducted gas exchange measurements for the canopy leaves of deciduous trees exposed to artificial warming during different seasons. The carbon dioxide assimilation rate at 20 °C (A 20 ) was not affected by warming, whereas that at 25 °C (A 25 ) tended to be higher in leaves exposed to warming. Warming increased the optimal temperature of photosynthesis by increasing the activation energy for the maximum rate of carboxylation. Regression analysis indicated that both GT and DL strongly influenced gas exchange characteristics. Sensitivity analysis revealed that DL affected A without obvious effects on the temperature dependence of A, whereas GT almost maintained constant A 20 and strongly influenced the temperature dependence. These results indicate that GT and DL have different influences on photosynthesis; GT and DL affect the 'slope' and intercept' of the temperature dependence of photosynthesis, respectively. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Association of neovascular age-related macular degeneration with month and season of birth in Italy

    PubMed Central

    Longo, Antonio; Casuccio, Alessandra; Pani, Luca; Avitabile, Teresio; Cillino, Salvatore; Uva, Maurizio G.; Bonfiglio, Vincenza; Russo, Andrea; Parisi, Guglielmo; Cennamo, Gilda; Furino, Claudio; Parravano, Mariacristina; Xoxi, Entela; Reibaldi, Michele

    2017-01-01

    In order to investigate the influence of season and month of birth on the risk of neovascular age-related macular degeneration (n-AMD) in Italy, we evaluated the month birth and sex of all patients, recorded in the anti-vascular endothelial growth factor (VEGF) monitoring registry of the Italian Medicines Agency, born between 1925–1944, who received intravitreal anti-VEGF injections for n-AMD between January 1, 2013 and July 29, 2015. The numbers of all births in Italy in the same years, extracted from the Italian National Institute of Statistics, were used to calculate the expected number of n-AMD cases. Overall, 45,845 patients (19,207 men, 26,638 women) received intravitreal anti-VEGF for n-AMD; in the same years, 20,140,426 people (10,334,262 male, 9,806,164 female) were born in Italy. Comparing the observed number of n-AMD cases with the expected number of n- AMD cases in each season, we found that the season-specific risk for n-AMD was 2.5% higher for those born in summer (OR=1.03, Bonferroni-corrected P=0.008) and 3% lower for those born in winter (OR=0.96, Bonferroni-corrected P=0.0004). When considering the month of birth, the risk of n-AMD was 5.9% lower for people born in January (OR=0.93, Bonferroni-corrected P=0.0012). The factors causing such differences should be determined. PMID:27997361

  19. Experimental climate warming decreases photosynthetic efficiency of lichens in an arid South African ecosystem.

    PubMed

    Maphangwa, Khumbudzo Walter; Musil, Charles F; Raitt, Lincoln; Zedda, Luciana

    2012-05-01

    Elevated temperatures and diminished precipitation amounts accompanying climate warming in arid ecosystems are expected to have adverse effects on the photosynthesis of lichen species sensitive to elevated temperature and/or water limitation. This premise was tested by artificially elevating temperatures (increase 2.1-3.8°C) and reducing the amounts of fog and dew precipitation (decrease 30.1-31.9%), in an approximation of future climate warming scenarios, using transparent hexagonal open-top warming chambers placed around natural populations of four lichen species (Xanthoparmelia austroafricana, X. hyporhytida , Xanthoparmelia. sp., Xanthomaculina hottentotta) at a dry inland site and two lichen species (Teloschistes capensis and Ramalina sp.) at a humid coastal site in the arid South African Succulent Karoo Biome. Effective photosynthetic quantum yields ([Formula: see text]) were measured hourly throughout the day at monthly intervals in pre-hydrated lichens present in the open-top warming chambers and in controls which comprised demarcated plots of equivalent open-top warming chamber dimensions constructed from 5-cm-diameter mesh steel fencing. The cumulative effects of the elevated temperatures and diminished precipitation amounts in the open-top warming chambers resulted in significant decreases in lichen [Formula: see text]. The decreases were more pronounced in lichens from the dry inland site (decline 34.1-46.1%) than in those from the humid coastal site (decline 11.3-13.7%), most frequent and prominent in lichens at both sites during the dry summer season, and generally of greatest magnitude at or after the solar noon in all seasons. Based on these results, we conclude that climate warming interacting with reduced precipitation will negatively affect carbon balances in endemic lichens by increasing desiccation damage and reducing photosynthetic activity time, leading to increased incidences of mortality.

  20. Specificity Responses of Grasshoppers in Temperate Grasslands to Diel Asymmetric Warming

    PubMed Central

    Wu, Tingjuan; Hao, Shuguang; Sun, Osbert Jianxin; Kang, Le

    2012-01-01

    Background Global warming is characterized by not only an increase in the daily mean temperature, but also a diel asymmetric pattern. However, most of the current studies on climate change have only concerned with the mean values of the warming trend. Although many studies have been conducted concerning the responses of insects to climate change, studies that address the issue of diel asymmetric warming under field conditions are not found in the literature. Methodology/Principal Findings We conducted a field climate manipulative experiment and investigated developmental and demographic responses to diel asymmetric warming in three grasshopper species (an early-season species Dasyhippus barbipes, a mid-season species Oedaleus asiaticus, and a late-season species Chorthippus fallax). It was found that warming generally advanced the development of eggs and nymphs, but had no apparent impacts on the hatching rate of eggs, the emergence rate of nymphs and the survival and fecundity of adults in all the three species. Nighttime warming was more effective in advancing egg development than the daytime warming. The emergence time of adults was differentially advanced by warming in the three species; it was advanced by 5.64 days in C. fallax, 3.55 days in O. asiaticus, and 1.96 days in D. barbipes. This phenological advancement was associated with increases in the effective GDDs accumulation. Conclusions/Significance Results in this study indicate that the responses of the three grasshopper species to warming are influenced by several factors, including species traits, developmental stage, and the thermal sensitivity of the species. Moreover, species with diapausing eggs are less responsive to changes in temperature regimes, suggesting that development of diapausing eggs is a protective mechanism in early-season grasshopper for avoiding the risk of pre-winter hatching. Our results highlight the need to consider the complex relationships between climate change and

  1. Dry season mean monthly flow and harmonic mean flow regression equations for selected ungaged basins in Arkansas

    USGS Publications Warehouse

    Breaker, Brian K.

    2015-01-01

    Equations for two regions were found to be statistically significant for developing regression equations for estimating harmonic mean flows at ungaged basins; thus, equations are applicable only to streams in those respective regions in Arkansas. Regression equations for dry season mean monthly flows are applicable only to streams located throughout Arkansas. All regression equations are applicable only to unaltered streams where flows were not significantly affected by regulation, diversion, or urbanization. The median number of years used for dry season mean monthly flow calculation was 43, and the median number of years used for harmonic mean flow calculations was 34 for region 1 and 43 for region 2.

  2. Seasonal ozone levels and control by seasonal meteorology

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pagnotti, V.

    1990-02-01

    Meteorological data, particularly 850-MB level temperatures, for Fort Totten, New York (1980) and Atlantic City, New Jersey (1981-1988) were examined for any relationship to seasonal ozone levels. Other radiosonde stations in the Northeast were utilized for 1983 and 1986, years of widely differing ozone levels. Statistics for selected parameters and years are presented. Emphasis is placed on recurring warm temperature regimes in high ozone years. Successive occurrences or episodes of high temperatures characterize seasonally high ozone years. Seasonally persistent high temperatures are related to seasonally chronic high ozone. An example is presented relating the broad-scale climatologically anomalous pattern of highmore » temperatures to anomalous circulation patterns at the 700-MB level.« less

  3. Plants regulate the effects of experimental warming on the soil microbial community in an alpine scrub ecosystem.

    PubMed

    Ma, Zhiliang; Zhao, Wenqiang; Zhao, Chunzhang; Wang, Dong; Liu, Mei; Li, Dandan; Liu, Qing

    2018-01-01

    Information on how soil microbial communities respond to warming is still scarce for alpine scrub ecosystems. We conducted a field experiment with two plant treatments (plant removal or undisturbed) subjected to warmed or unwarmed conditions to examine the effects of warming and plant removal on soil microbial community structures during the growing season in a Sibiraea angustata scrubland of the eastern Qinghai-Tibetan Plateau. The results indicate that experimental warming significantly influenced soil microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN), but the warming effects were dependent on the plant treatments and sampling seasons. In the plant-removal plots, warming did not affect most of the microbial variables, while in the undisturbed plots, warming significantly increased the abundances of actinomycete and Gram-positive bacterial groups during the mid-growing season (July), but it did not affect the fungi groups. Plant removal significantly reduced fungal abundance throughout the growing season and significantly altered the soil microbial community structure in July. The interaction between warming and plant removal significantly influenced the soil MBC and MBN and the abundances of total microbes, bacteria and actinomycete throughout the growing season. Experimental warming significantly reduced the abundance of rare taxa, while the interaction between warming and plant removal tended to have strong effects on the abundant taxa. These findings suggest that the responses of soil microbial communities to warming are regulated by plant communities. These results provide new insights into how soil microbial community structure responds to climatic warming in alpine scrub ecosystems.

  4. Plants regulate the effects of experimental warming on the soil microbial community in an alpine scrub ecosystem

    PubMed Central

    Ma, Zhiliang; Zhao, Wenqiang; Zhao, Chunzhang; Wang, Dong; Liu, Mei; Li, Dandan

    2018-01-01

    Information on how soil microbial communities respond to warming is still scarce for alpine scrub ecosystems. We conducted a field experiment with two plant treatments (plant removal or undisturbed) subjected to warmed or unwarmed conditions to examine the effects of warming and plant removal on soil microbial community structures during the growing season in a Sibiraea angustata scrubland of the eastern Qinghai–Tibetan Plateau. The results indicate that experimental warming significantly influenced soil microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN), but the warming effects were dependent on the plant treatments and sampling seasons. In the plant-removal plots, warming did not affect most of the microbial variables, while in the undisturbed plots, warming significantly increased the abundances of actinomycete and Gram-positive bacterial groups during the mid-growing season (July), but it did not affect the fungi groups. Plant removal significantly reduced fungal abundance throughout the growing season and significantly altered the soil microbial community structure in July. The interaction between warming and plant removal significantly influenced the soil MBC and MBN and the abundances of total microbes, bacteria and actinomycete throughout the growing season. Experimental warming significantly reduced the abundance of rare taxa, while the interaction between warming and plant removal tended to have strong effects on the abundant taxa. These findings suggest that the responses of soil microbial communities to warming are regulated by plant communities. These results provide new insights into how soil microbial community structure responds to climatic warming in alpine scrub ecosystems. PMID:29668711

  5. Seasonal changes of concentrations of inorganic and organic nitrogen in coastal marine sediments

    NASA Astrophysics Data System (ADS)

    Yamada, Hisashi; Kayama, Mitsu; Fujisawa, Kuniyasu

    1987-05-01

    The seasonal fluctuations of the concentration of nitrogenous compounds in sediments was investigated for three regions of the Seto Inland Sea in Japan; the variation of nitrogenous compounds in sediments was also studied in a laboratory experiment. The amounts of ammonium, dissolved organic nitrogen, nitrite and nitrate, as percentages of the dissolved total nitrogen of the interstitial water, were in the ranges of 47-99%, 10-50%, 0·1-0·6% and 0·3-4·1%, respectively. Ammonium was the major component and organic nitrogen was the next most important. The concentrations of these nitrogenous compounds changed seasonally: dissolved total nitrogen was higher in the warm month of September than in May; ammonium increased in warm months and decreased in cold months, but nitrite and nitrate increased in cold months. It was possible to explain the seasonal fluctuation of nitrogenous compounds in terms of the rates of the metabolic pathways of nitrogen in the sediments. Ammonium was not necessarily correlated with dissolved organic nitrogen. From this, it was considered that ammonium did not occur from solubilization of particulate organic nitrogen followed by mineralization, but from direct mineralization of particulate organic nitrogen in sediments. For the sediments of Suho Nada, Hiuchi Nada and station B-47 in Beppu Bay, the ratio of dissolved ammonium to adsorbed ammonium in the sediments was in the range 10-25%, but the ratio was 60-70% of adsorbed ammonium in the considerably anaerobic sediments at station B-45 in Beppu Bay. The ratio of dissolved ammonium to adsorbed ammonium increased with the increase of the concentration of sulfide in sediments. It was recognized that the anaerobic conditions of the sediments led to the dissolution of adsorbed ammonium.

  6. Seasonal and ENSO Influences on the Stable Isotopic Composition of Galápagos Precipitation

    NASA Astrophysics Data System (ADS)

    Martin, N. J.; Conroy, J. L.; Noone, D.; Cobb, K. M.; Konecky, B. L.; Rea, S.

    2018-01-01

    The origin of stable isotopic variability in precipitation over time and space is critical to the interpretation of stable isotope-based paleoclimate proxies. In the eastern equatorial Pacific, modern stable isotope measurements in precipitation (δ18Op and δDp) are sparse and largely unevaluated in the literature, although insights from such analyses would benefit the interpretations of several regional isotope-based paleoclimate records. Here we present a new 3.5 year record of daily-resolved δ18Op and δDp from Santa Cruz, Galápagos. With a prior 13 year record of monthly δ18Op and δDp from the island, these new data reveal controls on the stable isotopic composition of regional precipitation on event to interannual time scales. Overall, we find Galápagos δ18Op is significantly correlated with precipitation amount on daily and monthly time scales. The majority of Galápagos rain events are drizzle, or garúa, derived from local marine boundary layer vapor, with corresponding high δ18Op values due to the local source and increased evaporation and equilibration of smaller drops with boundary layer vapor. On monthly time scales, only precipitation in very strong, warm season El Niño months has substantially lower δ18Op values, as the sea surface temperature threshold for deep convection (28°C) is only surpassed at these times. The 2015/2016 El Niño event did not produce strong precipitation or δ18Op anomalies due to the short period of warm SST anomalies, which did not extend into the peak of the warm season. Eastern Pacific proxy isotope records may be biased toward periods of high rainfall during strong to very strong El Niño events.

  7. Interactive Vegetation Phenology, Soil Moisture, and Monthly Temperature Forecasts

    NASA Technical Reports Server (NTRS)

    Koster, R. D.; Walker, G. K.

    2015-01-01

    The time scales that characterize the variations of vegetation phenology are generally much longer than those that characterize atmospheric processes. The explicit modeling of phenological processes in an atmospheric forecast system thus has the potential to provide skill to subseasonal or seasonal forecasts. We examine this possibility here using a forecast system fitted with a dynamic vegetation phenology model. We perform three experiments, each consisting of 128 independent warm-season monthly forecasts: 1) an experiment in which both soil moisture states and carbon states (e.g., those determining leaf area index) are initialized realistically, 2) an experiment in which the carbon states are prescribed to climatology throughout the forecasts, and 3) an experiment in which both the carbon and soil moisture states are prescribed to climatology throughout the forecasts. Evaluating the monthly forecasts of air temperature in each ensemble against observations, as well as quantifying the inherent predictability of temperature within each ensemble, shows that dynamic phenology can indeed contribute positively to subseasonal forecasts, though only to a small extent, with an impact dwarfed by that of soil moisture.

  8. A remarkable climate warming hiatus over Northeast China since 1998

    NASA Astrophysics Data System (ADS)

    Sun, Xiubao; Ren, Guoyu; Ren, Yuyu; Fang, Yihe; Liu, Yulian; Xue, Xiaoying; Zhang, Panfeng

    2017-07-01

    Characteristics and causes of global warming hiatus (GWH) phenomenon have received much attention in recent years. Monthly mean data of land surface air maximum temperature (Tmax), minimum temperature (Tmin), and mean temperature (Tmean) of 118 national stations since 1951 in Northeast China are used in this paper to analyze the changes of land surface air temperature in recent 64 years with an emphasis on the GWH period. The results show that (1) from 1951 to 2014, the warming trends of Tmax, Tmin, and Tmean are 0.20, 0.42, and 0.34 °C/decade respectively for the whole area, with the warming rate of Tmin about two times of Tmax, and the upward trend of Tmean obviously higher than mainland China and global averages; (2) in the period 1998-2014, the annual mean temperature consistently exhibits a cooling phenomenon in Northeast China, and the trends of Tmax, Tmin, and Tmean are -0.36, -0.14, and -0.28 °C/decade respectively; (3) in the GWH period, seasonal mean cooling mainly occurs in northern winter (DJF) and spring (MAM), but northern summer (JJA) and autumn (SON) still experience a warming, implying that the annual mean temperature decrease is controlled by the remarkable cooling of winter and spring; (4) compared to the global and mainland China averages, the hiatus phenomenon is more evident in Northeast China, and the cooling trends are more obvious in the cold season; (5) the Northeast China cooling trend occurs under the circulation background of the negative phase Arctic Oscillation (AO), and it is also closely related to strengthening of the Siberia High (SH) and the East Asian Trough (EAT), and the stronger East Asian winter monsoon (EAWM) over the GWH period.

  9. Shifting seasonal cycles of surface ozone: the role of regional vs. global emission changes

    NASA Astrophysics Data System (ADS)

    Clifton, O.; Fiore, A. M.; Correa, G. J.; Naik, V.; Horowitz, L. W.

    2013-12-01

    Surface-level ozone seasonal cycles vary in shape and in magnitude with location. These variations reflect local contributions, whose influence differs each month, from regional anthropogenic and natural precursor emissions, as well as ozone transported from various sources. We focus on two U.S. regions with markedly different seasonal cycles over recent decades: the Northeast and the InterMountain West. In the Northeast, there are peak ozone values in the summer months due to high regional NOx emissions, abundant sunlight and isoprene emissions during this season. The lower NOx emissions in the InterMountain West combined with higher altitude where transported 'background' ozone is larger, leads to a weak spring maximum. Parrish et al. [2013] report a shift in seasonal cycles to earlier months in spring over recent decades at remote sites. We investigate here the role of changing global and regional ozone precursor emissions over the 21st century. With GFDL's fully coupled climate chemistry model CM3, we use selected Representative Concentration Pathways (RCP) scenarios developed for the Coupled Model Intercomparison Project Phase 5 (CMIP5) in support of IPCC AR 5, and several sensitivity simulations, to examine the impacts of regional and global emissions on surface ozone seasonal cycles throughout the 21st century. In RCP8.5, an extreme climate warming scenario, methane doubles from the present to the end of the 21st century, whereas in RCP4.5, a more moderate climate warming scenario, there is a small (~10%) decrease of methane. For RCP8.5, global mean surface temperature increases by 4.5 K, and for RCP4.5, by 1.4 K. In RCP8.5 and RCP4.5, NOx emissions decrease globally by 70.1% and 52.3%, respectively, by the end of the 21st century. These regional NOx reductions shift the ozone maximum in the Northeast from summer to late winter/early spring, resembling the present-day seasonal cycle over the InterMountain West. Over the InterMoutain West, surface ozone also

  10. Intra-Seasonal Monthly Oscillations in Stratospheric NCEP Data and Model Results

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Mengel, J. G.; Huang, F. T.; Nash, E. R.

    2009-01-01

    Intra-seasonal oscillations (ISO) are observed in the zonal-mean of mesospheric wind and temperature measurements-and the numerical spectral model (NSM) generates such oscillations. Relatively large temperature ISO are evident also in stratospheric CPC (NCEP) data at high latitudes, where the NSM produces amplitudes around 3 K at 30 km. Analyzing the NCEP data for the years 1996-2006, we find in Fourier spectra signatures of oscillations with periods between 1.7 and 3 months. With statistical confidence levels exceeding 70%, the spectral features are induced by nonlinear interactions involving the annual and semi-annual variations. The synthesized data show for the 10-year average that the temperature ISO peak in winter, having amplitudes close to 4 K. The synthesized complete spectrum for periods around 2 months produces oscillations, varying from year to year, which can reach peak amplitudes of 15 and 5 K respectively at northern and southern polar latitudes.

  11. Terrestrial carbon cycle affected by non-uniform climate warming

    NASA Astrophysics Data System (ADS)

    Xia, Jianyang; Chen, Jiquan; Piao, Shilong; Ciais, Philippe; Luo, Yiqi; Wan, Shiqiang

    2014-03-01

    Feedbacks between the terrestrial carbon cycle and climate change could affect many ecosystem functions and services, such as food production, carbon sequestration and climate regulation. The rate of climate warming varies on diurnal and seasonal timescales. A synthesis of global air temperature data reveals a greater rate of warming in winter than in summer in northern mid and high latitudes, and the inverse pattern in some tropical regions. The data also reveal a decline in the diurnal temperature range over 51% of the global land area and an increase over only 13%, because night-time temperatures in most locations have risen faster than daytime temperatures. Analyses of satellite data, model simulations and in situ observations suggest that the impact of seasonal warming varies between regions. For example, spring warming has largely stimulated ecosystem productivity at latitudes between 30° and 90° N, but suppressed productivity in other regions. Contrasting impacts of day- and night-time warming on plant carbon gain and loss are apparent in many regions. We argue that ascertaining the effects of non-uniform climate warming on terrestrial ecosystems is a key challenge in carbon cycle research.

  12. Dynamics of Necrophagous Insect and Tissue Bacteria for Postmortem Interval Estimation During the Warm Season in Romania.

    PubMed

    Iancu, Lavinia; Sahlean, Tiberiu; Purcarea, Cristina

    2016-01-01

    The estimation of postmortem interval (PMI) is affected by several factors including the cause of death, the place where the body lay after death, and the weather conditions during decomposition. Given the climatic differences among biogeographic locations, the understanding of necrophagous insect species biology and ecology is required when estimating PMI. The current experimental model was developed in Romania during the warm season in an outdoor location. The aim of the study was to identify the necrophagous insect species diversity and dynamics, and to detect the bacterial species present during decomposition in order to determine if their presence or incidence timing could be useful to estimate PMI. The decomposition process of domestic swine carcasses was monitored throughout a 14-wk period (10 July-10 October 2013), along with a daily record of meteorological parameters. The chronological succession of necrophagous entomofauna comprised nine Diptera species, with the dominant presence of Chrysomya albiceps (Wiedemann 1819) (Calliphoridae), while only two Coleoptera species were identified, Dermestes undulatus (L. 1758) and Creophilus maxillosus Brahm 1970. The bacterial diversity and dynamics from the mouth and rectum tissues, and third-instar dipteran larvae were identified using denaturing gradient gel electrophoresis analysis and sequencing of bacterial 16S rRNA gene fragments. Throughout the decomposition process, two main bacterial chronological groups were differentiated, represented by Firmicutes and Gammaproteobacteria. Twenty-six taxa from the rectal cavity and 22 from the mouth cavity were identified, with the dominant phylum in both these cavities corresponding to Firmicutes. The present data strengthen the postmortem entomological and microbial information for the warm season in this temperate-continental area, as well as the role of microbes in carcass decomposition. © The Authors 2015. Published by Oxford University Press on behalf of

  13. Innovative trend analysis of annual and seasonal air temperature and rainfall in the Yangtze River Basin, China during 1960-2015

    NASA Astrophysics Data System (ADS)

    Cui, Lifang; Wang, Lunche; Lai, Zhongping; Tian, Qing; Liu, Wen; Li, Jun

    2017-11-01

    The variation characteristics of air temperature and precipitation in the Yangtze River Basin (YRB), China during 1960-2015 were analysed using a linear regression (LR) analysis, a Mann-Kendall (MK) test with Sen's slope estimator and Sen's innovative trend analysis (ITA). The results showed that the annual maximum, minimum and mean temperature significantly increased at the rate of 0.15°C/10yr, 0.23°C/10yr and 0.19°C/10yr, respectively, over the whole study area during 1960-2015. The warming magnitudes for the above variables during 1980-2015 were much higher than those during 1960-2015:0.38°C/10yr, 0.35°C/10yr and 0.36°C/10yr, respectively. The seasonal maximum, minimum and mean temperature significantly increased in the spring, autumn and winter seasons during 1960-2015. Although the summer temperatures also increased at some extent, only the minimum temperature showed a significant increasing trend. Meanwhile, the highest rate of increase of seasonal mean temperature occurred in winter (0.24°C/10yr) during 1960-2015 and spring (0.50°C/10yr) during 1980-2015, which indicated that the significant warming trend for the whole YRB could be attributed to the remarkable temperature increases in winter and spring months. However, both the annual and seasonal warming magnitudes showed large regional differences, and a higher warming rate was detected in the eastern YRB and the western source region of the Yangtze River on the Qinghai-Tibetan Plateau (QTP). Additionally, annual precipitation increased by approximately 12.02 mm/10yr during 1960-2015 but decreased at the rate of 19.63 mm/10yr during 1980-2015. There were decreasing trends for precipitation in all four seasons since 1980 in the YRB, and a significant increasing trend was only detected in summer since 1960 (12.37 mm/10yr). Overall, a warming-wetting trend was detected in the south-eastern and north-western YRB, while there was a warming-drying trend in middle regions.

  14. Seasonal nitrogen effects on nutritive value in binary mixtures of tall fescue and bermudagrass

    USDA-ARS?s Scientific Manuscript database

    Year-round forage production is feasible in much of the southeastern USA through utilization of cool- and warm-season forages. This study determined changes in herbage nutritive value in binary mixtures of cool-season, tall fescue [Schedonorus arundinaceus (Schreb.) Dumort], and warm-season, bermuda...

  15. Prediction of monthly-seasonal precipitation using coupled SVD patterns between soil moisture and subsequent precipitation

    Treesearch

    Yongqiang Liu

    2003-01-01

    It was suggested in a recent statistical correlation analysis that predictability of monthly-seasonal precipitation could be improved by using coupled singular value decomposition (SVD) pattems between soil moisture and precipitation instead of their values at individual locations. This study provides predictive evidence for this suggestion by comparing skills of two...

  16. Spatial patterns of soil moisture connected to monthly-seasonal precipitation variability in a monsoon region

    Treesearch

    Yongqiang Liu

    2003-01-01

    The relations between monthly-seasonal soil moisture and precipitation variability are investigated by identifying the coupled patterns of the two hydrological fields using singular value decomposition (SVD). SVD is a technique of principal component analysis similar to empirical orthogonal knctions (EOF). However, it is applied to two variables simultaneously and is...

  17. Cost-effectiveness of inactivated seasonal influenza vaccination in a cohort of Thai children ≤60 months of age

    PubMed Central

    Suntarattiwong, Piyarat; Ditsungnoen, Darunee; Pallas, Sarah E.; Abimbola, Taiwo O.; Klungthong, Chonticha; Fernandez, Stefan; Srisarang, Suchada; Chotpitayasunondh, Tawee; Dawood, Fatimah S.; Olsen, Sonja J.; Lindblade, Kim A.

    2017-01-01

    Background Vaccination is the best measure to prevent influenza. We conducted a cost-effectiveness evaluation of trivalent inactivated seasonal influenza vaccination, compared to no vaccination, in children ≤60 months of age participating in a prospective cohort study in Bangkok, Thailand. Methods A static decision tree model was constructed to simulate the population of children in the cohort. Proportions of children with laboratory-confirmed influenza were derived from children followed weekly. The societal perspective and one-year analytic horizon were used for each influenza season; the model was repeated for three influenza seasons (2012–2014). Direct and indirect costs associated with influenza illness were collected and summed. Cost of the trivalent inactivated seasonal influenza vaccine (IIV3) including promotion, administration, and supervision cost was added for children who were vaccinated. Quality-adjusted life years (QALY), derived from literature, were used to quantify health outcomes. The incremental cost-effectiveness ratio (ICER) was calculated as the difference in the expected total costs between the vaccinated and unvaccinated groups divided by the difference in QALYs for both groups. Results Compared to no vaccination, IIV3 vaccination among children ≤60 months in our cohort was not cost-effective in the introductory year (2012 season; 24,450 USD/QALY gained), highly cost-effective in the 2013 season (554 USD/QALY gained), and cost-effective in the 2014 season (16,200 USD/QALY gained). Conclusion The cost-effectiveness of IIV3 vaccination among children participating in the cohort study varied by influenza season, with vaccine cost and proportion of high-risk children demonstrating the greatest influence in sensitivity analyses. Vaccinating children against influenza can be economically favorable depending on the maturity of the program, influenza vaccine performance, and target population. PMID:28837594

  18. Cost-effectiveness of inactivated seasonal influenza vaccination in a cohort of Thai children ≤60 months of age.

    PubMed

    Kittikraisak, Wanitchaya; Suntarattiwong, Piyarat; Ditsungnoen, Darunee; Pallas, Sarah E; Abimbola, Taiwo O; Klungthong, Chonticha; Fernandez, Stefan; Srisarang, Suchada; Chotpitayasunondh, Tawee; Dawood, Fatimah S; Olsen, Sonja J; Lindblade, Kim A

    2017-01-01

    Vaccination is the best measure to prevent influenza. We conducted a cost-effectiveness evaluation of trivalent inactivated seasonal influenza vaccination, compared to no vaccination, in children ≤60 months of age participating in a prospective cohort study in Bangkok, Thailand. A static decision tree model was constructed to simulate the population of children in the cohort. Proportions of children with laboratory-confirmed influenza were derived from children followed weekly. The societal perspective and one-year analytic horizon were used for each influenza season; the model was repeated for three influenza seasons (2012-2014). Direct and indirect costs associated with influenza illness were collected and summed. Cost of the trivalent inactivated seasonal influenza vaccine (IIV3) including promotion, administration, and supervision cost was added for children who were vaccinated. Quality-adjusted life years (QALY), derived from literature, were used to quantify health outcomes. The incremental cost-effectiveness ratio (ICER) was calculated as the difference in the expected total costs between the vaccinated and unvaccinated groups divided by the difference in QALYs for both groups. Compared to no vaccination, IIV3 vaccination among children ≤60 months in our cohort was not cost-effective in the introductory year (2012 season; 24,450 USD/QALY gained), highly cost-effective in the 2013 season (554 USD/QALY gained), and cost-effective in the 2014 season (16,200 USD/QALY gained). The cost-effectiveness of IIV3 vaccination among children participating in the cohort study varied by influenza season, with vaccine cost and proportion of high-risk children demonstrating the greatest influence in sensitivity analyses. Vaccinating children against influenza can be economically favorable depending on the maturity of the program, influenza vaccine performance, and target population.

  19. Free boundary models for mosquito range movement driven by climate warming.

    PubMed

    Bao, Wendi; Du, Yihong; Lin, Zhigui; Zhu, Huaiping

    2018-03-01

    As vectors, mosquitoes transmit numerous mosquito-borne diseases. Among the many factors affecting the distribution and density of mosquitoes, climate change and warming have been increasingly recognized as major ones. In this paper, we make use of three diffusive logistic models with free boundary in one space dimension to explore the impact of climate warming on the movement of mosquito range. First, a general model incorporating temperature change with location and time is introduced. In order to gain insights of the model, a simplified version of the model with the change of temperature depending only on location is analyzed theoretically, for which the dynamical behavior is completely determined and presented. The general model can be modified into a more realistic one of seasonal succession type, to take into account of the seasonal changes of mosquito movements during each year, where the general model applies only for the time period of the warm seasons of the year, and during the cold season, the mosquito range is fixed and the population is assumed to be in a hibernating status. For both the general model and the seasonal succession model, our numerical simulations indicate that the long-time dynamical behavior is qualitatively similar to the simplified model, and the effect of climate warming on the movement of mosquitoes can be easily captured. Moreover, our analysis reveals that hibernating enhances the chances of survival and successful spreading of the mosquitoes, but it slows down the spreading speed.

  20. Seasonality in ocean microbial communities.

    PubMed

    Giovannoni, Stephen J; Vergin, Kevin L

    2012-02-10

    Ocean warming occurs every year in seasonal cycles that can help us to understand long-term responses of plankton to climate change. Rhythmic seasonal patterns of microbial community turnover are revealed when high-resolution measurements of microbial plankton diversity are applied to samples collected in lengthy time series. Seasonal cycles in microbial plankton are complex, but the expansion of fixed ocean stations monitoring long-term change and the development of automated instrumentation are providing the time-series data needed to understand how these cycles vary across broad geographical scales. By accumulating data and using predictive modeling, we gain insights into changes that will occur as the ocean surface continues to warm and as the extent and duration of ocean stratification increase. These developments will enable marine scientists to predict changes in geochemical cycles mediated by microbial communities and to gauge their broader impacts.

  1. The influence of an extended Atlantic hurricane season on inland flooding potential in the southeastern United States

    NASA Astrophysics Data System (ADS)

    Stone, Monica H.; Cohen, Sagy

    2017-03-01

    Recent tropical cyclones, like Hurricane Katrina, have been some of the worst the United States has experienced. Tropical cyclones are expected to intensify, bringing about 20 % more precipitation, in the near future in response to global climate warming. Further, global climate warming may extend the hurricane season. This study focuses on four major river basins (Neches, Pearl, Mobile, and Roanoke) in the southeastern United States that are frequently impacted by tropical cyclones. An analysis of the timing of tropical cyclones that impact these river basins found that most occur during the low-discharge season and thus rarely produce riverine flooding conditions. However, an extension of the current hurricane season of June-November could encroach upon the high-discharge seasons in these basins, increasing the susceptibility for riverine hurricane-induced flooding. Our results indicate that 28-180 % more days would be at risk of flooding from an average tropical cyclone with an extension of the hurricane season to May-December (just 2 months longer). Future research should aim to extend this analysis to all river basins in the United States that are impacted by tropical cyclones in order to provide a bigger picture of which areas are likely to experience the worst increases in flooding risk due to a probable extension of the hurricane season with expected global climate change in the near future.

  2. Aerosol Indirect Effect on Warm Clouds over Eastern China Using Combined CALIOP and MODIS Observations

    NASA Astrophysics Data System (ADS)

    Guo, Jianping; Wang, Fu; Huang, Jingfeng; Li, Xiaowen

    2015-04-01

    Aerosol, one of key components of the climate system, is highly variable, both temporally and spatially. It often exerts great influences on the cloud-precipitation chain processes by serving as CCN/IN, altering cloud microphysics and its life cycle. Yet, the aerosol indirect effect on clouds remains largely unknown, because the initial changes in clouds due to aerosols may be enhanced or dampened by such feedback processes as modified cloud dynamics, or evaporation of the smaller droplets due to the competition for water vapor. In this study, we attempted to quantify the aerosol effects on warm cloud over eastern China, based on near-simultaneous retrievals from MODIS/AQUA, CALIOP/CALIPSO and CPR/CLOUDSAT during the period 2006 to 2010. The seasonality of aerosol from ground-based PM10 is quite different from that estimated from MODIS AOD. This result is corroborated by lower level profile of aerosol occurrence frequency from CALIOP, indicating the significant role CALIOP could play in aerosol-cloud interaction. The combined use of CALIOP and CPR facilitate the process to exactly determine the (vertical) position of warm cloud relative to aerosol, out of six scenarios in terms of aerosol-cloud mixing status in terms of aerosol-cloud mixing status, which shows as follows: AO (Aerosol only), CO (Cloud only), SASC (Single aerosol-single cloud), SADC (single aerosol-double cloud), DASC (double aerosol-single cloud), and others. Results shows that about 54% of all the cases belong to mixed status, among all the collocated aerosol-cloud cases. Under mixed condition, a boomerang shape is observed, i.e., reduced cloud droplet radius (CDR) is associated with increasing aerosol at moderate aerosol pollution (AOD<0.4), becoming saturated at AOD of 0.5, followed by an increase in CDR with aerosol. In contrast, there is no such boomerang shape found for (aerosol-cloud) separated cases. We categorize dataset into warm-season and cold-season subsets to figure out how the

  3. How can monthly to seasonal forecasts help to better manage power systems? (Invited)

    NASA Astrophysics Data System (ADS)

    Dubus, L.; Troccoli, A.

    2013-12-01

    The energy industry increasingly depends on weather and climate, at all space and time scales. This is especially true in countries with volunteer renewable energies development policies. There is no doubt that Energy and Meteorology is a burgeoning inter-sectoral discipline. It is also clear that the catalyst for the stronger interaction between these two sectors is the renewed and fervent interest in renewable energies, especially wind and solar power. Recent progress in meteorology has led to a marked increase in the knowledge of the climate system and in the ability to forecast climate on monthly to seasonal time scales. Several studies have already demonstrated the effectiveness of using these forecasts for energy operations, for instance for hydro-power applications. However, it is also obvious that scientific progress on its own is not sufficient to increase the value of weather forecasts. The process of integration of new meteorological products into operational tools and decision making processes is not straightforward but it is at least as important as the scientific discovery. In turn, such integration requires effective communication between users and providers of these products. We will present some important aspects of energy systems in which monthly to seasonal forecasts can bring useful, if not vital, information, and we will give some examples of encouraging energy/meteorology collaborations. We will also provide some suggestions for a strengthened collaboration into the future.

  4. Nutritive Value Response of Native Warm-Season Forage Grasses to Harvest Intervals and Durations in Mixed Stands

    PubMed Central

    Temu, Vitalis W.; Rude, Brian J.; Baldwin, Brian S.

    2014-01-01

    Interest in management of native warm-season grasses for multiple uses is growing in southeastern USA. Forage quality response of early-succession mixed stands of big bluestem (BB, Andropogon gerardii), indiangrass (IG, Sorghastrum nutans), and little bluestem (SG, Schizachyrium scoparium) to harvest intervals (30-, 40-, 60-, 90 or 120-d) and durations (one or two years) were assessed in crop-field buffers. Over three years, phased harvestings were initiated in May, on sets of randomized plots, ≥90 cm apart, in five replications (blocks) to produce one-, two-, and three-year-old stands, by the third year. Whole-plot regrowths were machine-harvested after collecting species (IG and LB) sample tillers for leafiness estimates. Species-specific leaf area (SLA) and leaf-to-stem ratio (LSR) were greater for early-season harvests and shorter intervals. In a similar pattern, whole-plot crude protein concentrations were greatest for the 30-d (74 g·kg−1 DM) and the least (40 g·kg−1 DM) for the 120-d interval. Corresponding neutral detergent fiber (NDF) values were the lowest (620 g·kg−1 DM) and highest (710 g·kg−1 DM), respectively. In vitro dry matter and NDF digestibility were greater for early-season harvests at shorter intervals (63 and 720 g·kg−1 DM). With strategic harvesting, similar stands may produce quality hay for beef cattle weight gain. PMID:27135504

  5. Sub-seasonal prediction over East Asia during boreal summer using the ECCC monthly forecasting system

    NASA Astrophysics Data System (ADS)

    Liang, Ping; Lin, Hai

    2018-02-01

    A useful sub-seasonal forecast is of great societal and economical value in the highly populated East Asian region, especially during boreal summer when frequent extreme events such as heat waves and persistent heavy rainfalls occur. Despite recent interest and development in sub-seasonal prediction, it is still unclear how skillful dynamical forecasting systems are in East Asia beyond 2 weeks. In this study we evaluate the sub-seasonal prediction over East Asia during boreal summer in the operational monthly forecasting system of Environment and Climate Change Canada (ECCC).Results show that the climatological intra-seasonal oscillation (CISO) of East Asian summer monsoonis reasonably well captured. Statistically significant forecast skill of 2-meter air temperature (T2m) is achieved for all lead times up to week 4 (days 26-32) over East China and Northeast Asia, which is consistent with the skill in 500 hPa geopotential height (Z500). Significant forecast skill of precipitation, however, is limited to the week of days 5-11. Possible sources of predictability on the sub-seasonal time scale are analyzed. The weekly mean T2m anomaly over East China is found to be linked to an eastward propagating extratropical Rossby wave from the North Atlantic across Europe to East Asia. The Madden-Julian Oscillation (MJO) and El Nino-Southern Oscillation (ENSO) are also likely to influence the forecast skill of T2m at the sub-seasonal timescale over East Asia.

  6. Climate Prediction Center - Seasonal Color Maps

    Science.gov Websites

    HOME > Outlook Maps > Monthly to Seasonal Outlooks > Seasonal Outlooks > Color Monthly & ; Seasonal Outlooks Monthly & Seasonal Climate Outlooks Banner Issued: 17 May 2018 [EXPERIMENTAL TWO

  7. Assessing the magnitude and timing of anthropogenic warming of a shallow aquifer: example from Virginia Beach, USA

    USGS Publications Warehouse

    Eggleston, John R.; McCoy, Kurt J.

    2015-01-01

    Groundwater temperature measurements in a shallow coastal aquifer in Virginia Beach, Virginia, USA, suggest groundwater warming of +4.1 °C relative to deeper geothermal gradients. Observed warming is related to timing and depth of influence of two potential thermal drivers—atmospheric temperature increases and urbanization. Results indicate that up to 30 % of groundwater warming at the water table can be attributed to atmospheric warming while up to 70 % of warming can be attributed to urbanization. Groundwater temperature readings to 30-m depth correlate positively with percentage of impervious cover and negatively with percentage of tree canopy cover; thus, these two land-use metrics explain up to 70 % of warming at the water table. Analytical and numerical modeling results indicate that an average vertical groundwater temperature profile for the study area, constructed from repeat measurement at 11 locations over 15 months, is consistent with the timing of land-use change over the past century in Virginia Beach. The magnitude of human-induced warming at the water table (+4.1 °C) is twice the current seasonal temperature variation, indicating the potential for ecological impacts on wetlands and estuaries receiving groundwater discharge from shallow aquifers.

  8. Monthly to seasonal low flow prediction: statistical versus dynamical models

    NASA Astrophysics Data System (ADS)

    Ionita-Scholz, Monica; Klein, Bastian; Meissner, Dennis; Rademacher, Silke

    2016-04-01

    While the societal and economical impacts of floods are well documented and assessable, the impacts of lows flows are less studied and sometimes overlooked. For example, over the western part of Europe, due to intense inland waterway transportation, the economical loses due to low flows are often similar compared to the ones due to floods. In general, the low flow aspect has the tendency to be underestimated by the scientific community. One of the best examples in this respect is the facts that at European level most of the countries have an (early) flood alert system, but in many cases no real information regarding the development, evolution and impacts of droughts. Low flows, occurring during dry periods, may result in several types of problems to society and economy: e.g. lack of water for drinking, irrigation, industrial use and power production, deterioration of water quality, inland waterway transport, agriculture, tourism, issuing and renewing waste disposal permits, and for assessing the impact of prolonged drought on aquatic ecosystems. As such, the ever-increasing demand on water resources calls for better a management, understanding and prediction of the water deficit situation and for more reliable and extended studies regarding the evolution of the low flow situations. In order to find an optimized monthly to seasonal forecast procedure for the German waterways, the Federal Institute of Hydrology (BfG) is exploring multiple approaches at the moment. On the one hand, based on the operational short- to medium-range forecasting chain, existing hydrological models are forced with two different hydro-meteorological inputs: (i) resampled historical meteorology generated by the Ensemble Streamflow Prediction approach and (ii) ensemble (re-) forecasts of ECMWF's global coupled ocean-atmosphere general circulation model, which have to be downscaled and bias corrected before feeding the hydrological models. As a second approach BfG evaluates in cooperation with

  9. Seasonal modulation of the Asian summer monsoon between the Medieval Warm Period and Little Ice Age: a multi model study

    NASA Astrophysics Data System (ADS)

    Kamae, Youichi; Kawana, Toshi; Oshiro, Megumi; Ueda, Hiroaki

    2017-12-01

    Instrumental and proxy records indicate remarkable global climate variability over the last millennium, influenced by solar irradiance, Earth's orbital parameters, volcanic eruptions and human activities. Numerical model simulations and proxy data suggest an enhanced Asian summer monsoon during the Medieval Warm Period (MWP) compared to the Little Ice Age (LIA). Using multiple climate model simulations, we show that anomalous seasonal insolation over the Northern Hemisphere due to a long cycle of orbital parameters results in a modulation of the Asian summer monsoon transition between the MWP and LIA. Ten climate model simulations prescribing historical radiative forcing that includes orbital parameters consistently reproduce an enhanced MWP Asian monsoon in late summer and a weakened monsoon in early summer. Weakened, then enhanced Northern Hemisphere insolation before and after June leads to a seasonally asymmetric temperature response over the Eurasian continent, resulting in a seasonal reversal of the signs of MWP-LIA anomalies in land-sea thermal contrast, atmospheric circulation, and rainfall from early to late summer. This seasonal asymmetry in monsoon response is consistently found among the different climate models and is reproduced by an idealized model simulation forced solely by orbital parameters. The results of this study indicate that slow variation in the Earth's orbital parameters contributes to centennial variability in the Asian monsoon transition.[Figure not available: see fulltext.

  10. Predicting the Poaceae pollen season: six month-ahead forecasting and identification of relevant features

    NASA Astrophysics Data System (ADS)

    Navares, Ricardo; Aznarte, José Luis

    2017-04-01

    In this paper, we approach the problem of predicting the concentrations of Poaceae pollen which define the main pollination season in the city of Madrid. A classification-based approach, based on a computational intelligence model (random forests), is applied to forecast the dates in which risk concentration levels are to be observed. Unlike previous works, the proposal extends the range of forecasting horizons up to 6 months ahead. Furthermore, the proposed model allows to determine the most influential factors for each horizon, making no assumptions about the significance of the weather features. The performace of the proposed model proves it as a successful tool for allergy patients in preventing and minimizing the exposure to risky pollen concentrations and for researchers to gain a deeper insight on the factors driving the pollination season.

  11. Predicting the Poaceae pollen season: six month-ahead forecasting and identification of relevant features.

    PubMed

    Navares, Ricardo; Aznarte, José Luis

    2017-04-01

    In this paper, we approach the problem of predicting the concentrations of Poaceae pollen which define the main pollination season in the city of Madrid. A classification-based approach, based on a computational intelligence model (random forests), is applied to forecast the dates in which risk concentration levels are to be observed. Unlike previous works, the proposal extends the range of forecasting horizons up to 6 months ahead. Furthermore, the proposed model allows to determine the most influential factors for each horizon, making no assumptions about the significance of the weather features. The performace of the proposed model proves it as a successful tool for allergy patients in preventing and minimizing the exposure to risky pollen concentrations and for researchers to gain a deeper insight on the factors driving the pollination season.

  12. Observed warming over northern South America has an anthropogenic origin

    NASA Astrophysics Data System (ADS)

    Barkhordarian, Armineh; von Storch, Hans; Zorita, Eduardo; Loikith, Paul C.; Mechoso, Carlos R.

    2017-10-01

    We investigate whether the recently observed trends in daily maximum and minimum near-surface air temperature (Tmax and Tmin, respectively) over South America (SA) are consistent with the simulated response of Tmin and Tmax to anthropogenic forcing. Results indicate that the recently observed warming in the dry seasons is well beyond the range of natural (internal) variability. In the wet season the natural modes of variability explain a substantial portion of Tmin and Tmax variability. We demonstrate that the large-scale component of greenhouse gas (GHG) forcing is detectable in dry-seasonal warming. However, none of the global and regional climate change projections reproduce the observed warming of up to 0.6 K/Decade in Tmax in 1983-2012 over northern SA during the austral spring (SON). Thus, besides the global manifestation of GHG forcing, other external drivers have an imprint. Using aerosols-only forcing simulations, our results provide evidence that anthropogenic aerosols also have a detectable influence in SON and that the indirect effect of aerosols on cloud's lifetime is more compatible with the observed record. In addition, there is an increasing trend in the observed incoming solar radiation over northern SA in SON, which is larger than expected from natural (internal) variability alone. We further show that in the dry seasons the spread of projected trends based on the RCP4.5 scenario derived from 30 CMIP5 models encompasses the observed area-averaged trends in Tmin and Tmax. This may imply that the observed excessive warming in the dry seasons serve as an illustration of plausible future expected change in the region.

  13. Factors Influencing Knowledge, Food Safety Practices and Food Preferences During Warm Weather of Salmonella and Campylobacter Cases in South Australia.

    PubMed

    Milazzo, Adriana; Giles, Lynne C; Zhang, Ying; Koehler, Ann P; Hiller, Janet E; Bi, Peng

    2017-03-01

    To assess food safety practices, food shopping preferences, and eating behaviors of people diagnosed with Salmonella or Campylobacter infection in the warm seasons, and to identify socioeconomic factors associated with behavior and practices. A cross-sectional survey was conducted among Salmonella and Campylobacter cases with onset of illness from January 1 to March 31, 2013. Multivariable logistic regression analyses examined relationships between socioeconomic position and food safety knowledge and practices, shopping and food preferences, and preferences, perceptions, and knowledge about food safety information on warm days. Respondents in our study engaged in unsafe personal and food hygiene practices. They also carried out unsafe food preparation practices, and had poor knowledge of foods associated with an increased risk of foodborne illness. Socioeconomic position did not influence food safety practices. We found that people's reported eating behaviors and food preferences were influenced by warm weather. Our study has explored preferences and practices related to food safety in the warm season months. This is important given that warmer ambient temperatures are projected to rise, both globally and in Australia, and will have a substantial effect on the burden of infectious gastroenteritis including foodborne disease. Our results provide information about modifiable behaviors for the prevention of foodborne illness in the household in the warm weather and the need for information to be disseminated across the general population. An understanding of the knowledge and factors associated with human behavior during warmer weather is critical for public health interventions on foodborne prevention.

  14. Mean annual, seasonal, and monthly precipitation and runoff in Arkansas, 1951-2011

    USGS Publications Warehouse

    Pugh, Aaron L.; Westerman, Drew A.

    2014-01-01

    This report describes long-term annual, seasonal, and monthly means for precipitation and runoff in Arkansas for the period from 1951 through 2011. Precipitation means were estimated using data from the Parameter-elevation Regressions on Independent Slopes Model database; while total runoff, groundwater runoff, and surface runoff means were estimated using data from 123 active and inactive U.S. Geological Survey continuous-record streamflow-gaging stations located in Arkansas and surrounding States. Annual precipitation in Arkansas for the period from 1951 through 2011 had a mean of 49.8 inches. Of the six physiographic sections in Arkansas, the Ouachita Mountains had the largest mean annual precipitation at 53.0 inches, while the Springfield-Salem plateaus had the smallest mean annual precipitation at 45.5 inches. The mean annual total runoff for Arkansas was 17.8 inches. The Ouachita Mountains had the largest mean annual total runoff at 20.4 inches, while the Springfield-Salem plateaus had the smallest mean annual total runoff at 15.0 inches. Runoff is diminished during the dry season, which is attributed to increased losses from evapotranspiration, consumptive uses including irrigation, and increased withdrawals for public and private water supplies. The decline in runoff during the dry season is observed across the State in all physiographic sections. Spatial results for precipitation and runoff are presented in a series of maps that are available for download from the publication Web page in georeferenced raster formats.

  15. Daily, monthly, seasonal, and annual ammonia emissions from Southern High Plains cattle feedyards.

    PubMed

    Todd, Richard W; Cole, N Andy; Rhoades, Marty B; Parker, David B; Casey, Kenneth D

    2011-01-01

    Ammonia emitted from beef cattle feedyards adds excess reactive N to the environment, contributes to degraded air quality as a precursor to secondary particulate matter, and represents a significant loss of N from beef cattle feedyards. We used open path laser spectroscopy and an inverse dispersion model to quantify daily, monthly, seasonal, and annual NH emissions during 2 yr from two commercial cattle feedyards in the Panhandle High Plains of Texas. Annual patterns of NH fluxes correlated with air temperature, with the greatest fluxes (>100 kg ha d) during the summer and the lowest fluxes (<15 kg ha d) during the winter. Mean monthly per capita emission rate (PCER) of NH-N at one feedyard ranged from 31 g NH-N head d (January) to 207 g NH-N head d (October), when increased dietary crude protein from wet distillers grains elevated emissions. Ammonia N emissions at the other feedyard ranged from 36 g NH-N head d (January) to 121 g NH-N head d (September). Monthly fractional NH-N loss ranged from a low of 19 to 24% to a high of 80 to 85% of fed N at the two feedyards. Seasonal PCER at the two feedyards averaged 60 to 71 g NH-N head d during winter and 103 to 158 g NH-N head d during summer. Annually, PCER was 115 and 80 g NH-N head d at the two feedyards, which represented 59 and 52% of N fed to the cattle. Detailed studies are needed to determine the effect of management and environmental variables such as diet, temperature, precipitation, and manure water content on NH emissions. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  16. The Role of Frozen Soil in Groundwater Discharge Predictions for Warming Alpine Watersheds

    NASA Astrophysics Data System (ADS)

    Evans, Sarah G.; Ge, Shemin; Voss, Clifford I.; Molotch, Noah P.

    2018-03-01

    Climate warming may alter the quantity and timing of groundwater discharge to streams in high alpine watersheds due to changes in the timing of the duration of seasonal freezing in the subsurface and snowmelt recharge. It is imperative to understand the effects of seasonal freezing and recharge on groundwater discharge to streams in warming alpine watersheds as streamflow originating from these watersheds is a critical water resource for downstream users. This study evaluates how climate warming may alter groundwater discharge due to changes in seasonally frozen ground and snowmelt using a 2-D coupled flow and heat transport model with freeze and thaw capabilities for variably saturated media. The model is applied to a representative snowmelt-dominated watershed in the Rocky Mountains of central Colorado, USA, with snowmelt time series reconstructed from a 12 year data set of hydrometeorological records and satellite-derived snow covered area. Model analyses indicate that the duration of seasonal freezing in the subsurface controls groundwater discharge to streams, while snowmelt timing controls groundwater discharge to hillslope faces. Climate warming causes changes to subsurface ice content and duration, rerouting groundwater flow paths but not altering the total magnitude of future groundwater discharge outside of the bounds of hydrologic parameter uncertainties. These findings suggest that frozen soil routines play an important role for predicting the future location of groundwater discharge in watersheds underlain by seasonally frozen ground.

  17. The role of frozen soil in groundwater discharge predictions for warming alpine watersheds

    USGS Publications Warehouse

    Evans, Sarah G.; Ge, Shemin; Voss, Clifford I.; Molotch, Noah P.

    2018-01-01

    Climate warming may alter the quantity and timing of groundwater discharge to streams in high alpine watersheds due to changes in the timing of the duration of seasonal freezing in the subsurface and snowmelt recharge. It is imperative to understand the effects of seasonal freezing and recharge on groundwater discharge to streams in warming alpine watersheds as streamflow originating from these watersheds is a critical water resource for downstream users. This study evaluates how climate warming may alter groundwater discharge due to changes in seasonally frozen ground and snowmelt using a 2‐D coupled flow and heat transport model with freeze and thaw capabilities for variably saturated media. The model is applied to a representative snowmelt‐dominated watershed in the Rocky Mountains of central Colorado, USA, with snowmelt time series reconstructed from a 12 year data set of hydrometeorological records and satellite‐derived snow covered area. Model analyses indicate that the duration of seasonal freezing in the subsurface controls groundwater discharge to streams, while snowmelt timing controls groundwater discharge to hillslope faces. Climate warming causes changes to subsurface ice content and duration, rerouting groundwater flow paths but not altering the total magnitude of future groundwater discharge outside of the bounds of hydrologic parameter uncertainties. These findings suggest that frozen soil routines play an important role for predicting the future location of groundwater discharge in watersheds underlain by seasonally frozen ground.

  18. Seasonal below-ground metabolism in switchgrass

    USDA-ARS?s Scientific Manuscript database

    Switchgrass (Panicum virgatum) a perennial, polyploid, C4 warm-season grass is one of the foremost herbaceous species being advanced as a source of biomass for biofuel end uses. At the end of every growing season, the aerial tissues senesce, and the below-ground rhizomes become dormant. Future growt...

  19. Diabatic Initialization of Mesoscale Models in the Southeastern United States: Can 0 to 12h Warm Season QPF be Improved?

    NASA Technical Reports Server (NTRS)

    Lapenta, William M.; Bradshaw, Tom; Burks, Jason; Darden, Chris; Dembek, Scott

    2003-01-01

    It is well known that numerical warm season quantitative precipitation forecasts lack significant skill for numerous reasons. Some are related to the model--it may lack physical processes required to realistically simulate convection or the numerical algorithms and dynamics employed may not be adequate. Others are related to initialization-mesoscale features play an important role in convective initialization and atmospheric observation systems are incapable of properly depicting the three-dimensional stability structure at the mesoscale. The purpose of this study is to determine if a mesoscale model initialized with a diabatic initialization scheme can improve short-term (0 to 12h) warm season quantitative precipitation forecasts in the Southeastern United States. The Local Analysis and Prediction System (LAPS) developed at the Forecast System Laboratory is used to diabatically initialize the Pennsylvania State University/National center for Atmospheric Research (PSUNCAR) Mesoscale Model version 5 (MM5). The SPORT Center runs LAPS operationally on an hourly cycle to produce analyses on a 15 km covering the eastern 2/3 of the United States. The 20 km National Centers for Environmental Prediction (NCEP) Rapid Update Cycle analyses are used for the background fields. Standard observational data are acquired from MADIS with GOES/CRAFT Nexrad data acquired from in-house feeds. The MM5 is configured on a 140 x 140 12 km grid centered on Huntsville Alabama. Preliminary results indicate that MM5 runs initialized with LAPS produce improved 6 and 12h QPF threat scores compared with those initialized with the NCEP RUC.

  20. Diet and nutritional status among children 24-59 months by seasons in a mountainous area of Northern Vietnam in 2012.

    PubMed

    Huong, Le Thi; Xuan, Le Thi Thanh; Phuong, Le Hong; Huyen, Doan Thi Thu; Rocklöv, Joacim

    2014-01-01

    Seasonal variation affects food availability. However, it is not clear if it affects dietary intake and nutritional status of children in Vietnam. This paper aims at examining the seasonal variation in nutrition status and dietary intake of children aged 24-59 months. A repeated cross-sectional study design was used to collect data of changes in nutritional status and diets of children from 24 to 59 months through four seasons in Chiem Hoa district, Tuyen Quang province, a predominately rural mountainous province of northern Vietnam. The quantitative component includes anthropometric measurements, 24 hours dietary recall and socio-economic characteristics. The qualitative component was conducted through focus group discussions (FGDs) with mothers of the children surveyed in the quantitative component. The purpose of FGDs was to explore the food habits of children during the different seasons and the behaviours of their mothers in relation to the food that they provide during these seasons. The prevalence of underweight among children aged 24-59 months is estimated at around 20-25%; it peaked in summer (24.9%) and reached a low in winter (21.3%). The prevalence of stunting was highest in summer (29.8%) and lowest in winter (22.2%). The prevalence of wasting in children was higher in spring and autumn (14.3%) and lower in summer (9.3%). Energy intake of children was highest in the autumn (1259.3 kcal) and lowest in the summer (996.9 kcal). Most of the energy and the nutrient intakes during the four seasons did not meet the Vietnamese National Institute of Nutrition recommendation. Our study describes some seasonal variation in nutrition status and energy intake among children in a mountainous area northern Vietnam. Our study indicated that the prevalence of stunting and underweight was higher in summer and autumn, while the prevalence of wasting was higher in spring and autumn. Energy intake did not always meet national recommendations, especially in summer.

  1. Estimating influenza vaccine effectiveness using routine surveillance data among children aged 6-59 months for five consecutive influenza seasons.

    PubMed

    Su, Wei-Ju; Chan, Ta-Chien; Chuang, Pei-Hung; Liu, Yu-Lun; Lee, Ping-Ing; Liu, Ming-Tsan; Chuang, Jen-Hsiang

    2015-01-01

    We aimed to estimate the pooled vaccine effectiveness (VE) in children over five winters through data linkage of two existing surveillance systems. Five test-negative case-control studies were conducted from November to February during the 2004/2005 to 2008/2009 seasons. Sentinel physicians from the Viral Surveillance Network enrolled children aged 6-59 months with influenza-like illness to collect throat swabs. Through linking with a nationwide vaccination registry, we measured the VE with a logistic regression model adjusting for age, gender, and week of symptom onset. Both fixed-effects and random-effects models were used in the meta-analysis. Four thousand four hundred and ninety-four subjects were included. The proportion of influenza test-positive subjects across the five seasons was 11.5% (132/1151), 7.2% (41/572), 23.9% (189/791), 6.6% (75/1135), and 11.2% (95/845), respectively. The pooled VE was 62% (95% confidence interval (CI) 48-83%) in both meta-analysis models. By age category, VE was 51% (95% CI 23-68%) for those aged 6-23 months and 75% (95% CI 60-84%) for those aged 24-59 months. Influenza vaccination provided measurable protection against laboratory-confirmed influenza among children aged 6-59 months despite variations in the vaccine match during the 2004/2005 to 2008/2009 influenza seasons in Taiwan. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  2. Attaining whole-ecosystem warming using air and deep-soil heating methods with an elevated CO2 atmosphere

    NASA Astrophysics Data System (ADS)

    Hanson, Paul J.; Riggs, Jeffery S.; Nettles, W. Robert; Phillips, Jana R.; Krassovski, Misha B.; Hook, Leslie A.; Gu, Lianhong; Richardson, Andrew D.; Aubrecht, Donald M.; Ricciuto, Daniel M.; Warren, Jeffrey M.; Barbier, Charlotte

    2017-02-01

    This paper describes the operational methods to achieve and measure both deep-soil heating (0-3 m) and whole-ecosystem warming (WEW) appropriate to the scale of tall-stature, high-carbon, boreal forest peatlands. The methods were developed to allow scientists to provide a plausible set of ecosystem-warming scenarios within which immediate and longer-term (1 decade) responses of organisms (microbes to trees) and ecosystem functions (carbon, water and nutrient cycles) could be measured. Elevated CO2 was also incorporated to test how temperature responses may be modified by atmospheric CO2 effects on carbon cycle processes. The WEW approach was successful in sustaining a wide range of aboveground and belowground temperature treatments (+0, +2.25, +4.5, +6.75 and +9 °C) in large 115 m2 open-topped enclosures with elevated CO2 treatments (+0 to +500 ppm). Air warming across the entire 10 enclosure study required ˜ 90 % of the total energy for WEW ranging from 64 283 mega Joules (MJ) d-1 during the warm season to 80 102 MJ d-1 during cold months. Soil warming across the study required only 1.3 to 1.9 % of the energy used ranging from 954 to 1782 MJ d-1 of energy in the warm and cold seasons, respectively. The residual energy was consumed by measurement and communication systems. Sustained temperature and elevated CO2 treatments were only constrained by occasional high external winds. This paper contrasts the in situ WEW method with closely related field-warming approaches using both aboveground (air or infrared heating) and belowground-warming methods. It also includes a full discussion of confounding factors that need to be considered carefully in the interpretation of experimental results. The WEW method combining aboveground and deep-soil heating approaches enables observations of future temperature conditions not available in the current observational record, and therefore provides a plausible glimpse of future environmental conditions.

  3. Integrated rice-duck farming mitigates the global warming potential in rice season.

    PubMed

    Xu, Guochun; Liu, Xin; Wang, Qiangsheng; Yu, Xichen; Hang, Yuhao

    2017-01-01

    Integrated rice-duck farming (IRDF), as a mode of ecological agriculture, is an important way to realize sustainable development of agriculture. A 2-year split-plot field experiment was performed to evaluate the effects of IRDF on methane (CH 4 ) and nitrous oxide (N 2 O) emissions and its ecological mechanism in rice season. This experiment was conducted with two rice farming systems (FS) of IRDF and conventional farming (CF) under four paddy-upland rotation systems (PUR): rice-fallow (RF), annual straw incorporating in rice-wheat rotation system (RWS), annual straw-based biogas residues incorporating in rice-wheat rotation system (RWB), and rice-green manure (RGM). During the rice growing seasons, IRDF decreased the CH 4 emission by 8.80-16.68%, while increased the N 2 O emission by 4.23-15.20%, when compared to CF. Given that CH 4 emission contributed to 85.83-96.22% of global warming potential (GWP), the strong reduction in CH 4 emission led to a significantly lower GWP of IRDF as compared to CF. The reason for this trend was because IRDF has significant effect on dissolved oxygen (DO) and soil redox potential (Eh), which were two pivotal factors for CH 4 and N 2 O emissions in this study. The IRDF not only mitigates the GWP, but also increases the rice yield by 0.76-2.43% compared to CF. Moreover, compared to RWS system, RF, RWB and RGM systems significantly reduced CH 4 emission by 50.17%, 44.89% and 39.51%, respectively, while increased N 2 O emission by 10.58%, 14.60% and 23.90%, respectively. And RWS system had the highest GWP. These findings suggest that mitigating GWP and improving rice yield could be simultaneously achieved by the IRDF, and employing suitable PUR would benefit for relieving greenhouse effect. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. The Changing Energy Sources of Soil Respiration Seasonally and with Experimental Warming

    NASA Astrophysics Data System (ADS)

    Hicks Pries, C.; Angert, A.; Castanha, C.; Hilman, B.; Torn, M. S.

    2017-12-01

    Due to its importance in the global carbon cycle, soil respiration has been intensively measured. However, measurements are almost exclusively of CO2, which has limited our understanding of soil respiration's sources and its responses to climate change. Here, we show how dual CO2 and O2 measurements within the soil profile of a temperate forest can indicate how the energy sources driving soil respiration can change seasonally and with experimental warming. We calculated the apparent respiration quotient (ARQ), defined as CO2 produced/O2 consumed, calculated from gas soil concentrations and adjusted for differences in diffusion rates. The ARQ changes depending on the stoichiometry of the organic compounds utilized for energy by microbes and roots. Oxidation of carbohydrates and organic acids results in respiration quotients ≥1 while oxidation of lipids results in respiration quotients ≈0.7 with oxidation of proteins falling in between. We observed clear seasonal patterns in ARQ, with values ≈0.9 during the late spring and summer decreasing to 0.6-0.7 during the winter. These changes in ARQ imply carbohydrates are a more important energy source during the summer when trees are photosynthesizing and providing fresh substrate to both roots and microbes. During the winter, lipids, likely recycled within microbial biomass, are a more important energy source. Furthermore, winter ARQ was higher in heated plots (+4° relative to control) than in control plots, but only at 30 cm, possibly due to increased root activity with heating. These interpretations are supported by δ13CO2 values, which were relatively depleted in the winter and more enriched in the summer—lipids are more depleted in δ13C than are sugars. Consistent with the heating effect, there were strong correlations between temperature and ARQ and temperature and δ13C. Given the large differences in ARQ in this forest soil, we are looking into using ARQ to partition soil respiration fluxes based on

  5. Trends in annual, seasonal, and monthly streamflow characteristics at 227 streamgages in the Missouri River watershed, water years 1960-2011

    USGS Publications Warehouse

    Norton, Parker A.; Anderson, Mark T.; Stamm, John F.

    2014-01-01

    The Missouri River and its tributaries are an important resource that serve multiple uses including agriculture, energy, recreation, and municipal water supply. Understanding historical streamflow characteristics provides relevant guidance to adaptive management of these water resources. Streamflow records in the Missouri River watershed were examined for trends in time series of annual, seasonal, and monthly streamflow. A total of 227 streamgages having continuous observational records for water years 1960–2011 were examined. Kendall’s tau nonparametric test was used to determine statistical significance of trends in annual, seasonal, and monthly streamflow. A trend was considered statistically significant for a probability value less than or equal to 0.10 that the Kendall’s tau value equals zero. Significant trends in annual streamflow were indicated for 101 out of a total of 227 streamgages. The Missouri River watershed was divided into six watershed regions and trends within regions were examined. The western and the southern parts of the Missouri River watershed had downward trends in annual streamflow (56 streamgages), whereas the eastern part of the watershed had upward trends in streamflow (45 streamgages). Seasonal and monthly streamflow trends reflected prevailing annual streamflow trends within each watershed region.

  6. Trends and homogeneity of monthly, seasonal, and annual rainfall over arid region of Rajasthan, India

    NASA Astrophysics Data System (ADS)

    Meena, Hari Mohan; Machiwal, Deepesh; Santra, Priyabrata; Moharana, Pratap Chandra; Singh, D. V.

    2018-05-01

    Knowledge of rainfall variability is important for regional-scale planning and management of water resources in agriculture. This study explores spatio-temporal variations, trends, and homogeneity in monthly, seasonal, and annual rainfall series of 62 stations located in arid region of Rajasthan, India using 55 year (1957-2011) data. Box-whisker plots indicate presence of outliers and extremes in annual rainfall, which made the distribution of annual rainfall right-skewed. Mean and coefficient of variation (CV) of rainfall reveals a high inter-annual variability (CV > 200%) in the western portion where the mean annual rainfall is very low. A general gradient of the mean monthly, seasonal, and annual rainfall is visible from northwest to southeast direction, which is orthogonal to the gradient of CV. The Sen's innovative trend test is found over-sensitive in evaluating statistical significance of the rainfall trends, while the Mann-Kendall test identifies significantly increasing rainfall trends in June and September. Rainfall in July shows prominently decreasing trends although none of them are found statistically significant. Monsoon and annual rainfall show significantly increasing trends at only four stations. The magnitude of trends indicates that the rainfall is increasing at a mean rate of 1.11, 2.85, and 2.89 mm year-1 in August, monsoon season, and annual series. The rainfall is found homogeneous over most of the area except for few stations situated in the eastern and northwest portions where significantly increasing trends are observed. Findings of this study indicate that there are few increasing trends in rainfall of this Indian arid region.

  7. Seasonal Variations Preserved in an Extinct Neogene Scallop, Chesapecten, from Florida to Delaware, USA and its Implications for Paleobiogeography

    NASA Astrophysics Data System (ADS)

    Goewert, A. E.; Surge, D.

    2007-12-01

    the MMCO (Florida and Delaware, respectively) and 0.96‰ and -0.50‰ for the MPWI (Florida and Virginia, respectively), accounting for latitudinal effects. Temperatures during the MMCO from Florida shells ranged from 19.7 to 31.4°C, and from Delaware shells ranged from 13.3 to 26.1°C. These data reflect diminished seasonality from Florida to Delaware at that time. Prominant annual growth lines were not apparent in these shells, a common characteristic in tropical shells. Like the MMCO temperature estimates, temperature recorded in MPWI shells from Florida lacked seasonal variability, as expected from low latitudes, with temperatures ranging from 15.6 to 21.3°C. Furthermore, like the MMCO shells, prominent annual growth lines were not evident. MPWI shells from Virginia displayed seasonal temperatures from 2.7 to 20.1°C indicating warm- temperate conditions. We predicted annual growth line formation during summer months based on studies that show modern warm-temperate bivalves inhabiting mid to high latitudes form annual growth lines during summer months. However, isotope sclerochronology revealed that these scallops produced winter growth lines. These findings have important implications for paleoceanographic and atmospheric circulation during the MPWI.

  8. Irrigation enhances local warming with greater nocturnal warming effects than daytime cooling effects

    NASA Astrophysics Data System (ADS)

    Chen, Xing; Jeong, Su-Jong

    2018-02-01

    To meet the growing demand for food, land is being managed to be more productive using agricultural intensification practices, such as the use of irrigation. Understanding the specific environmental impacts of irrigation is a critical part of using it as a sustainable way to provide food security. However, our knowledge of irrigation effects on climate is still limited to daytime effects. This is a critical issue to define the effects of irrigation on warming related to greenhouse gases (GHGs). This study shows that irrigation led to an increasing temperature (0.002 °C year-1) by enhancing nighttime warming (0.009 °C year-1) more than daytime cooling (-0.007 °C year-1) during the dry season from 1961-2004 over the North China Plain (NCP), which is one of largest irrigated areas in the world. By implementing irrigation processes in regional climate model simulations, the consistent warming effect of irrigation on nighttime temperatures over the NCP was shown to match observations. The intensive nocturnal warming is attributed to energy storage in the wetter soil during the daytime, which contributed to the nighttime surface warming. Our results suggest that irrigation could locally amplify the warming related to GHGs, and this effect should be taken into account in future climate change projections.

  9. Earlier snowmelt and warming lead to earlier but not necessarily more plant growth.

    PubMed

    Livensperger, Carolyn; Steltzer, Heidi; Darrouzet-Nardi, Anthony; Sullivan, Patrick F; Wallenstein, Matthew; Weintraub, Michael N

    2016-01-01

    Climate change over the past ∼50 years has resulted in earlier occurrence of plant life-cycle events for many species. Across temperate, boreal and polar latitudes, earlier seasonal warming is considered the key mechanism leading to earlier leaf expansion and growth. Yet, in seasonally snow-covered ecosystems, the timing of spring plant growth may also be cued by snowmelt, which may occur earlier in a warmer climate. Multiple environmental cues protect plants from growing too early, but to understand how climate change will alter the timing and magnitude of plant growth, experiments need to independently manipulate temperature and snowmelt. Here, we demonstrate that altered seasonality through experimental warming and earlier snowmelt led to earlier plant growth, but the aboveground production response varied among plant functional groups. Earlier snowmelt without warming led to early leaf emergence, but often slowed the rate of leaf expansion and had limited effects on aboveground production. Experimental warming alone had small and inconsistent effects on aboveground phenology, while the effect of the combined treatment resembled that of early snowmelt alone. Experimental warming led to greater aboveground production among the graminoids, limited changes among deciduous shrubs and decreased production in one of the dominant evergreen shrubs. As a result, we predict that early onset of the growing season may favour early growing plant species, even those that do not shift the timing of leaf expansion. Published by Oxford University Press on behalf of the Annals of Botany Company.

  10. Seasonality in mortality and its relationship to temperature among the older population in Hanoi, Vietnam.

    PubMed

    Xuan, Le Thi Thanh; Egondi, Thaddaeus; Ngoan, Le Tran; Toan, Do Thi Thanh; Huong, Le Thi

    2014-01-01

    Several studies have established a relationship between temperature and mortality. In particular, older populations have been shown to be vulnerable to temperature effects. However, little information exists on the temperature-mortality relationship in Vietnam. This article aims to examine the monthly temperature-mortality relationship among older people in Hanoi, Vietnam, over the period between 2005 and 2010, and estimate seasonal patterns in mortality. We employed Generalized Additive Models, including smooth functions, to model the temperature-mortality relationships. A quasi-Poisson distribution was used to model overdispersion of death counts. Temporal trends, seasonality, and population size were adjusted for while estimating changes in monthly mortality over the study period. A cold month was defined as a month with a mean temperature below 19°C. This study found that the high peak of mortality coincided with low temperatures in the month of February 2008, during which the mean temperature was the lowest in the whole study period. There was a significant relationship between mean monthly temperature and mortality among the older people (p<0.01). Overall, there was a significant decrease in the number of deaths in the year 2009 during the study period. There was a 21% increase in the number of deaths during the cold season compared to the warm season. The increase in mortality during the cold period was higher among females compared to males (female: IRR [incidence relative risk] =1.23; male: IRR=1.18). Cold temperatures substantially increased mortality among the older population in Hanoi, Vietnam, and there were gender differences. Necessary preventive measures are required to mitigate temperature effects with greater attention to vulnerable groups.

  11. Future vegetation ecosystem response to warming climate over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Bao, Y.; Gao, Y.; Wang, Y.

    2017-12-01

    The amplified vegetation response to climate variability has been found over the Tibetan Plateau (TP) in recent decades. In this study, the potential impacts of 21st century climate change on the vegetation ecosystem over the TP are assessed based on the dynamic vegetation outputs of models from Coupled Model Intercomparison Project Phase 5 (CMIP5), and the sensitivity of the TP vegetation in response to warming climate was investigated. Models project a continuous and accelerating greening in future, especially in the eastern TP, which closely associates with the plant type upgrade due to the pronouncing warming in growing season.Vegetation leaf area index (LAI) increase well follows the global warming, suggesting the warming climate instead of co2 fertilization controlls the future TP plant growth. The warming spring may advance the start of green-up day and extend the growing season length. More carbon accumulation in vegetation and soil will intensify the TP carbon cycle and will keep it as a carbon sink in future. Keywords: Leaf Area Index (LAI), Climate Change, Global Dynamic Vegetation Models (DGVMs), CMIP5, Tibetan Plateau (TP)

  12. Weather conditions and visits to the medical wing of emergency rooms in a metropolitan area during the warm season in Israel: a predictive model

    NASA Astrophysics Data System (ADS)

    Novikov, Ilya; Kalter-Leibovici, Ofra; Chetrit, Angela; Stav, Nir; Epstein, Yoram

    2012-01-01

    Global climate changes affect health and present new challenges to healthcare systems. The aim of the present study was to analyze the pattern of visits to the medical wing of emergency rooms (ERs) in public hospitals during warm seasons, and to develop a predictive model that will forecast the number of visits to ERs 2 days ahead. Data on daily visits to the ERs of the four largest medical centers in the Tel-Aviv metropolitan area during the warm months of the year (April-October, 2001-2004), the corresponding daily meteorological data, daily electrical power consumption (a surrogate marker for air-conditioning), air-pollution parameters, and calendar information were obtained and used in the analyses. The predictive model employed a time series analysis with transitional Poisson regression. The concise multivariable model was highly accurate ( r 2 = 0.819). The contribution of mean daily temperature was small but significant: an increase of 1°C in ambient temperature was associated with a 1.47% increase in the number of ER visits ( P < 0.001). An increase in electrical power consumption significantly attenuated the effect of weather conditions on ER visits by 4% per 1,000 MWh ( P < 0.001). Higher daily mean SO2 concentrations were associated with a greater number of ER visits (1% per 1 ppb increment; P = 0.017). Calendar data were the main predictors of ER visits ( r 2 = 0.794). The predictive model was highly accurate in forecasting the number of visits to ERs 2 days ahead. The marginal effect of temperature on the number of ER visits can be attributed to behavioral adaptations, including the use of air-conditioning.

  13. Projected changes of thermal growing season over Northern Eurasia in a 1.5 °C and 2 °C warming world

    NASA Astrophysics Data System (ADS)

    Zhou, Baiquan; Zhai, Panmao; Chen, Yang; Yu, Rong

    2018-03-01

    Projected changes of the thermal growing season (TGS) over Northern Eurasia at 1.5 °C and 2 °C global warming levels are investigated using 22 CMIP5 models under both RCP4.5 and RCP8.5 scenarios. The multi-model mean projections indicate Northern Eurasia will experience extended and intensified TGSs in a warmer world. The prolongation of TGSs under 1.5 °C and 2 °C warming is attributed to both earlier onset and later termination, with the latter factor playing a dominating role. Interestingly, earlier onset is of greater importance under RCP4.5 than under RCP8.5 in prolonging TGS as the world warms by an additional 0.5 °C. Under both RCPs, growing degree day sum (GDD) above 5 °C is anticipated to increase by 0 °C-450 °C days and 0 °C-650 °C days over Northern Eurasia at 1.5 °C and 2 °C warming, respectively. However, effective GDD (EGDD) which accumulates optimum temperature for the growth of wheat, exhibits a decline in the south of Central Asia under warmer climates. Therefore, for wheat production over Northern Eurasia, adverse effects incurred by scorching temperatures and resultant inadequacy in water availability may counteract benefits from lengthening and warming TGS. In response to a future 1.5 °C and 2 °C warmer world, proper management and scientifically-tailored adaptation are imperative to optimize local-regional agricultural production.

  14. Warming effects on permafrost ecosystem carbon fluxes associated with plant nutrients.

    PubMed

    Li, Fei; Peng, Yunfeng; Natali, Susan M; Chen, Kelong; Han, Tianfeng; Yang, Guibiao; Ding, Jinzhi; Zhang, Dianye; Wang, Guanqin; Wang, Jun; Yu, Jianchun; Liu, Futing; Yang, Yuanhe

    2017-11-01

    Large uncertainties exist in carbon (C)-climate feedback in permafrost regions, partly due to an insufficient understanding of warming effects on nutrient availabilities and their subsequent impacts on vegetation C sequestration. Although a warming climate may promote a substantial release of soil C to the atmosphere, a warming-induced increase in soil nutrient availability may enhance plant productivity, thus offsetting C loss from microbial respiration. Here, we present evidence that the positive temperature effect on carbon dioxide (CO 2 ) fluxes may be weakened by reduced plant nitrogen (N) and phosphorous (P) concentrations in a Tibetan permafrost ecosystem. Although experimental warming initially enhanced ecosystem CO 2 uptake, the increased rate disappeared after the period of peak plant growth during the early growing season, even though soil moisture was not a limiting factor in this swamp meadow ecosystem. We observed that warming did not significantly affect soil extractable N or P during the period of peak growth, but decreased both N and P concentrations in the leaves of dominant plant species, likely caused by accelerated plant senescence in the warmed plots. The attenuated warming effect on CO 2 assimilation during the late growing season was associated with lowered leaf N and P concentrations. These findings suggest that warming-mediated nutrient changes may not always benefit ecosystem C uptake in permafrost regions, making our ability to predict the C balance in these warming-sensitive ecosystems more challenging than previously thought. © 2017 by the Ecological Society of America.

  15. Seasonal Life Cycle of Linepithema micans (Forel) (Hymenoptera: Formicidae) in Vineyards.

    PubMed

    Nondillo, A; Baronio, C A; Bernardi, D; Bueno, O C; Botton, M

    2016-08-01

    Linepithema micans (Forel) is considered to be the main ant species responsible for the spread of Eurhizococcus brasiliensis (Wille), a soil scale that damages vine plants in southern Brazil. In this work, the seasonal life cycle of L. micans was evaluated in vineyards to define the most appropriate time for the application of toxic baits for control. Ant nests were transported to the laboratory in plastic bags, and individual ants were separated into groups of eggs, larvae, pupae, workers, males, and queens, recording the number of individuals per colony. The seasonal life cycle of L. micans in the vineyards began in spring with the deposition of eggs by queens. During the warm months of the year (spring and summer), it was possible to observe nests consisting primarily of eggs and pupae. During the autumn and winter months, the colonies were composed predominantly of larvae and a reduction in eggs was observed. Because the main control strategy targets the larval stage of the insect, the application of toxic baits for the control of L. micans must be performed during the winter.

  16. The seasonality and geographic dependence of ENSO impacts on U.S. surface ozone variability

    NASA Astrophysics Data System (ADS)

    Xu, Li; Yu, Jin-Yi; Schnell, Jordan L.; Prather, Michael J.

    2017-04-01

    We examine the impact of El Niño-Southern Oscillation (ENSO) on surface ozone abundance observed over the continental United States (U.S.) during 1993-2013. The monthly ozone decreases (increases) during El Niño (La Niña) years with amplitude up to 1.8 ppb per standard deviation of Niño 3.4 index. The largest ENSO influences occur over two southern U.S. regions during fall when the ENSO develops and over two western U.S. regions during the winter to spring after the ENSO decays. ENSO affects surface ozone via chemical processes during warm seasons in southern regions, where favorable meteorological conditions occur, but via dynamic transport during cold seasons in western regions, where the ENSO-induced circulation variations are large. The geographic dependence and seasonality of the ENSO impacts imply that regulations regarding air quality and its exceedance need to be adjusted for different seasons and U.S. regions to account for the ENSO-driven patterns in surface ozone.

  17. Experimental warming of a mountain tundra increases soil CO2 effluxes and enhances CH4 and N2O uptake at Changbai Mountain, China

    PubMed Central

    Zhou, Yumei; Hagedorn, Frank; Zhou, Chunliang; Jiang, Xiaojie; Wang, Xiuxiu; Li, Mai-He

    2016-01-01

    Climatic warming is expected to particularly alter greenhouse gas (GHG) emissions from soils in cold ecosystems such as tundra. We used 1 m2 open-top chambers (OTCs) during three growing seasons to examine how warming (+0.8–1.2 °C) affects the fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) from alpine tundra soils. Results showed that OTC warming increased soil CO2 efflux by 141% in the first growing season and by 45% in the second and third growing season. The mean CH4 flux of the three growing seasons was −27.6 and −16.7 μg CH4-C m−2h−1 in the warmed and control treatment, respectively. Fluxes of N2O switched between net uptake and emission. Warming didn’t significantly affect N2O emission during the first and the second growing season, but stimulated N2O uptake in the third growing season. The global warming potential of GHG was clearly dominated by soil CO2 effluxes (>99%) and was increased by the OTC warming. In conclusion, soil temperature is the main controlling factor for soil respiration in this tundra. Climate warming will lead to higher soil CO2 emissions but also to an enhanced CH4 uptake with an overall increase of the global warming potential for tundra. PMID:26880107

  18. Seasonal and cryopreservation impacts on semen quality in boars

    USDA-ARS?s Scientific Manuscript database

    Seasonal boar infertility occurs worldwide and contributes to economic loss to the pork industry. The current study evaluated cooled vs cryopreserved semen quality of 11 Duroc boars collected in June (cool season) and August 2014 (warm season). Semen was cooled to 16°C (cooled) or frozen over liquid...

  19. Haida Months of the Year.

    ERIC Educational Resources Information Center

    Cogo, Robert

    Students are introduced to Haida vocabulary in this booklet which briefly describes the seasons and traditional seasonal activities of Southeastern Alaska Natives. The first section lists the months in English and Haida; e.g., January is "Taan Kungaay," or "Bear Hunting Month." The second section contains seasonal names in…

  20. Changes in vegetation phenology are not reflected in atmospheric CO2 and 13 C/12 C seasonality.

    PubMed

    Gonsamo, Alemu; D'Odorico, Petra; Chen, Jing M; Wu, Chaoyang; Buchmann, Nina

    2017-10-01

    Northern terrestrial ecosystems have shown global warming-induced advances in start, delays in end, and thus increased lengths of growing season and gross photosynthesis in recent decades. The tradeoffs between seasonal dynamics of two opposing fluxes, CO 2 uptake through photosynthesis and release through respiration, determine the influence of the terrestrial ecosystem on the atmospheric CO 2 and 13 C/ 12 C seasonality. Here, we use four CO 2 observation stations in the Northern Hemisphere, namely Alert, La Jolla, Point Barrow, and Mauna Loa Observatory, to determine how changes in vegetation productivity and phenology, respiration, and air temperature affect both the atmospheric CO 2 and 13 C/ 12 C seasonality. Since the 1960s, the only significant long-term trend of CO 2 and 13 C/ 12 C seasonality was observed at the northern most station, Alert, where the spring CO 2 drawdown dates advanced by 0.65 ± 0.55 days yr -1 , contributing to a nonsignificant increase in length of the CO 2 uptake period (0.74 ± 0.67 days yr -1 ). For Point Barrow station, vegetation phenology changes in well-watered ecosystems such as the Canadian and western Siberian wetlands contributed the most to 13 C/ 12 C seasonality while the CO 2 seasonality was primarily linked to nontree vegetation. Our results indicate significant increase in the Northern Hemisphere soil respiration. This means, increased respiration of 13 C depleted plant materials cancels out the 12 C gain from enhanced vegetation activities during the start and end of growing season. These findings suggest therefore that parallel warming-induced increases both in photosynthesis and respiration contribute to the long-term stability of CO 2 and 13 C/ 12 C seasonality under changing climate and vegetation activity. The summer photosynthesis and the soil respiration in the dormant seasons have become more vigorous which lead to increased peak-to-through CO 2 amplitude. As the relative magnitude of the increased

  1. Diet and nutritional status among children 24–59 months by seasons in a mountainous area of Northern Vietnam in 2012

    PubMed Central

    Huong, Le Thi; Xuan, Le Thi Thanh; Phuong, Le Hong; Huyen, Doan Thi Thu; Rocklöv, Joacim

    2014-01-01

    Background Seasonal variation affects food availability. However, it is not clear if it affects dietary intake and nutritional status of children in Vietnam. Objectives This paper aims at examining the seasonal variation in nutrition status and dietary intake of children aged 24–59 months. Design A repeated cross-sectional study design was used to collect data of changes in nutritional status and diets of children from 24 to 59 months through four seasons in Chiem Hoa district, Tuyen Quang province, a predominately rural mountainous province of northern Vietnam. The quantitative component includes anthropometric measurements, 24 hours dietary recall and socio-economic characteristics. The qualitative component was conducted through focus group discussions (FGDs) with mothers of the children surveyed in the quantitative component. The purpose of FGDs was to explore the food habits of children during the different seasons and the behaviours of their mothers in relation to the food that they provide during these seasons. Results The prevalence of underweight among children aged 24–59 months is estimated at around 20–25%; it peaked in summer (24.9%) and reached a low in winter (21.3%). The prevalence of stunting was highest in summer (29.8%) and lowest in winter (22.2%). The prevalence of wasting in children was higher in spring and autumn (14.3%) and lower in summer (9.3%). Energy intake of children was highest in the autumn (1259.3 kcal) and lowest in the summer (996.9 kcal). Most of the energy and the nutrient intakes during the four seasons did not meet the Vietnamese National Institute of Nutrition recommendation. Conclusions Our study describes some seasonal variation in nutrition status and energy intake among children in a mountainous area northern Vietnam. Our study indicated that the prevalence of stunting and underweight was higher in summer and autumn, while the prevalence of wasting was higher in spring and autumn. Energy intake did not always meet

  2. The phenology of Arctic Ocean surface warming.

    PubMed

    Steele, Michael; Dickinson, Suzanne

    2016-09-01

    In this work, we explore the seasonal relationships (i.e., the phenology) between sea ice retreat, sea surface temperature (SST), and atmospheric heat fluxes in the Pacific Sector of the Arctic Ocean, using satellite and reanalysis data. We find that where ice retreats early in most years, maximum summertime SSTs are usually warmer, relative to areas with later retreat. For any particular year, we find that anomalously early ice retreat generally leads to anomalously warm SSTs. However, this relationship is weak in the Chukchi Sea, where ocean advection plays a large role. It is also weak where retreat in a particular year happens earlier than usual, but still relatively late in the season, primarily because atmospheric heat fluxes are weak at that time. This result helps to explain the very different ocean warming responses found in two recent years with extreme ice retreat, 2007 and 2012. We also find that the timing of ice retreat impacts the date of maximum SST, owing to a change in the ocean surface buoyancy and momentum forcing that occurs in early August that we term the Late Summer Transition (LST). After the LST, enhanced mixing of the upper ocean leads to cooling of the ocean surface even while atmospheric heat fluxes are still weakly downward. Our results indicate that in the near-term, earlier ice retreat is likely to cause enhanced ocean surface warming in much of the Arctic Ocean, although not where ice retreat still occurs late in the season.

  3. Decadal warming causes a consistent and persistent shift from heterotrophic to autotrophic respiration in contrasting permafrost ecosystems.

    PubMed

    Hicks Pries, Caitlin E; van Logtestijn, Richard S P; Schuur, Edward A G; Natali, Susan M; Cornelissen, Johannes H C; Aerts, Rien; Dorrepaal, Ellen

    2015-12-01

    Soil carbon in permafrost ecosystems has the potential to become a major positive feedback to climate change if permafrost thaw increases heterotrophic decomposition. However, warming can also stimulate autotrophic production leading to increased ecosystem carbon storage-a negative climate change feedback. Few studies partitioning ecosystem respiration examine decadal warming effects or compare responses among ecosystems. Here, we first examined how 11 years of warming during different seasons affected autotrophic and heterotrophic respiration in a bryophyte-dominated peatland in Abisko, Sweden. We used natural abundance radiocarbon to partition ecosystem respiration into autotrophic respiration, associated with production, and heterotrophic decomposition. Summertime warming decreased the age of carbon respired by the ecosystem due to increased proportional contributions from autotrophic and young soil respiration and decreased proportional contributions from old soil. Summertime warming's large effect was due to not only warmer air temperatures during the growing season, but also to warmer deep soils year-round. Second, we compared ecosystem respiration responses between two contrasting ecosystems, the Abisko peatland and a tussock-dominated tundra in Healy, Alaska. Each ecosystem had two different timescales of warming (<5 years and over a decade). Despite the Abisko peatland having greater ecosystem respiration and larger contributions from heterotrophic respiration than the Healy tundra, both systems responded consistently to short- and long-term warming with increased respiration, increased autotrophic contributions to ecosystem respiration, and increased ratios of autotrophic to heterotrophic respiration. We did not detect an increase in old soil carbon losses with warming at either site. If increased autotrophic respiration is balanced by increased primary production, as is the case in the Healy tundra, warming will not cause these ecosystems to become

  4. Protected Area Tourism in a Changing Climate: Will Visitation at US National Parks Warm Up or Overheat?

    PubMed

    Fisichelli, Nicholas A; Schuurman, Gregor W; Monahan, William B; Ziesler, Pamela S

    2015-01-01

    Climate change will affect not only natural and cultural resources within protected areas but also tourism and visitation patterns. The U.S. National Park Service systematically collects data regarding its 270+ million annual recreation visits, and therefore provides an opportunity to examine how human visitation may respond to climate change from the tropics to the polar regions. To assess the relationship between climate and park visitation, we evaluated historical monthly mean air temperature and visitation data (1979-2013) at 340 parks and projected potential future visitation (2041-2060) based on two warming-climate scenarios and two visitation-growth scenarios. For the entire park system a third-order polynomial temperature model explained 69% of the variation in historical visitation trends. Visitation generally increased with increasing average monthly temperature, but decreased strongly with temperatures > 25°C. Linear to polynomial monthly temperature models also explained historical visitation at individual parks (R2 0.12-0.99, mean = 0.79, median = 0.87). Future visitation at almost all parks (95%) may change based on historical temperature, historical visitation, and future temperature projections. Warming-mediated increases in potential visitation are projected for most months in most parks (67-77% of months; range across future scenarios), resulting in future increases in total annual visits across the park system (8-23%) and expansion of the visitation season at individual parks (13-31 days). Although very warm months at some parks may see decreases in future visitation, this potential change represents a relatively small proportion of visitation across the national park system. A changing climate is likely to have cascading and complex effects on protected area visitation, management, and local economies. Results suggest that protected areas and neighboring communities that develop adaptation strategies for these changes may be able to both

  5. Protected Area Tourism in a Changing Climate: Will Visitation at US National Parks Warm Up or Overheat?

    PubMed Central

    Fisichelli, Nicholas A.; Schuurman, Gregor W.; Monahan, William B.; Ziesler, Pamela S.

    2015-01-01

    Climate change will affect not only natural and cultural resources within protected areas but also tourism and visitation patterns. The U.S. National Park Service systematically collects data regarding its 270+ million annual recreation visits, and therefore provides an opportunity to examine how human visitation may respond to climate change from the tropics to the polar regions. To assess the relationship between climate and park visitation, we evaluated historical monthly mean air temperature and visitation data (1979–2013) at 340 parks and projected potential future visitation (2041–2060) based on two warming-climate scenarios and two visitation-growth scenarios. For the entire park system a third-order polynomial temperature model explained 69% of the variation in historical visitation trends. Visitation generally increased with increasing average monthly temperature, but decreased strongly with temperatures > 25°C. Linear to polynomial monthly temperature models also explained historical visitation at individual parks (R2 0.12-0.99, mean = 0.79, median = 0.87). Future visitation at almost all parks (95%) may change based on historical temperature, historical visitation, and future temperature projections. Warming-mediated increases in potential visitation are projected for most months in most parks (67–77% of months; range across future scenarios), resulting in future increases in total annual visits across the park system (8–23%) and expansion of the visitation season at individual parks (13–31 days). Although very warm months at some parks may see decreases in future visitation, this potential change represents a relatively small proportion of visitation across the national park system. A changing climate is likely to have cascading and complex effects on protected area visitation, management, and local economies. Results suggest that protected areas and neighboring communities that develop adaptation strategies for these changes may be able to

  6. Climate Change of 4°C GlobalWarming above Pre-industrial Levels

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoxin; Jiang, Dabang; Lang, Xianmei

    2018-07-01

    Using a set of numerical experiments from 39 CMIP5 climate models, we project the emergence time for 4°C global warming with respect to pre-industrial levels and associated climate changes under the RCP8.5 greenhouse gas concentration scenario. Results show that, according to the 39 models, the median year in which 4°C global warming will occur is 2084. Based on the median results of models that project a 4°C global warming by 2100, land areas will generally exhibit stronger warming than the oceans annually and seasonally, and the strongest enhancement occurs in the Arctic, with the exception of the summer season. Change signals for temperature go outside its natural internal variabilities globally, and the signal-tonoise ratio averages 9.6 for the annual mean and ranges from 6.3 to 7.2 for the seasonal mean over the globe, with the greatest values appearing at low latitudes because of low noise. Decreased precipitation generally occurs in the subtropics, whilst increased precipitation mainly appears at high latitudes. The precipitation changes in most of the high latitudes are greater than the background variability, and the global mean signal-to-noise ratio is 0.5 and ranges from 0.2 to 0.4 for the annual and seasonal means, respectively. Attention should be paid to limiting global warming to 1.5°C, in which case temperature and precipitation will experience a far more moderate change than the natural internal variability. Large inter-model disagreement appears at high latitudes for temperature changes and at mid and low latitudes for precipitation changes. Overall, the intermodel consistency is better for temperature than for precipitation.

  7. Warm Season Temperatures and Emergency Department Visits in Atlanta, Georgia

    PubMed Central

    Winquist, Andrea; Grundstein, Andrew; Chang, Howard H.; Hess, Jeremy; Sarnat, Stefanie Ebelt

    2016-01-01

    Purpose Extreme heat events will likely increase in frequency with climate change. Heat-related health effects are better documented among the elderly than among younger age groups. We assessed associations between warm-season ambient temperature and emergency department (ED) visits across ages in Atlanta during 1993-2012. Methods We examined daily counts of ED visits with primary diagnoses of heat illness, fluid/electrolyte imbalances, renal disease, cardiorespiratory diseases, and intestinal infections by age group (0-4, 5-18, 19-64, 65+ years) in relation to daily maximum temperature (TMX) using Poisson time series models that included cubic terms for TMX at single-day lags of 0-6 days, controlling for maximum dew-point temperature, time trends, week day, holidays, and hospital participation periods. We estimated rate ratios (RRs) and 95% confidence intervals (CI) for TMX changes from 27 °C to 32 °C (25th to 75th percentile) and conducted extensive sensitivity analyses. Results We observed associations between TMX and ED visits for all internal causes, heat illness, fluid/electrolyte imbalances, renal diseases, asthma/wheeze, diabetes, and intestinal infections. Age groups with the strongest observed associations were 65+ years for all internal causes [lag 0 RR (CI)=1.022 (1.016-1.028)] and diabetes [lag 0 RR=1.050 (1.008-1.095)]; 19-64 years for fluid/electrolyte imbalances [lag 0 RR=1.170 (1.136-1.205)] and renal disease [lag 1 RR=1.082 (1.065-1.099)]; and 5-18 years for asthma/wheeze [lag 2 RR=1.059 (1.030-1.088)] and intestinal infections [lag 1 RR=1.120 (1.041-1.205)]. Conclusions Varying strengths of associations between TMX and ED visits by age suggest that optimal interventions and health-impact projections would account for varying heat health impacts across ages. PMID:26922412

  8. Attaining whole-ecosystem warming using air and deep-soil heating methods with an elevated CO2 atmosphere

    DOE PAGES

    Hanson, Paul J.; Riggs, Jeffery S.; Nettles, IV, W. Robert; ...

    2017-02-24

    This paper describes the operational methods to achieve and measure both deep-soil heating (0–3 m) and whole-ecosystem warming (WEW) appropriate to the scale of tall-stature, high-carbon, boreal forest peatlands. The methods were developed to allow scientists to provide a plausible set of ecosystem-warming scenarios within which immediate and longer-term (1 decade) responses of organisms (microbes to trees) and ecosystem functions (carbon, water and nutrient cycles) could be measured. Elevated CO 2 was also incorporated to test how temperature responses may be modified by atmospheric CO 2 effects on carbon cycle processes. The WEW approach was successful in sustaining a widemore » range of aboveground and belowground temperature treatments (+0, +2.25, +4.5, +6.75 and +9 °C) in large 115 m 2 open-topped enclosures with elevated CO 2 treatments (+0 to +500 ppm). Air warming across the entire 10 enclosure study required ~90 % of the total energy for WEW ranging from 64 283 mega Joules (MJ) d –1 during the warm season to 80 102 MJ d –1 during cold months. Soil warming across the study required only 1.3 to 1.9 % of the energy used ranging from 954 to 1782 MJ d –1 of energy in the warm and cold seasons, respectively. The residual energy was consumed by measurement and communication systems. Sustained temperature and elevated CO 2 treatments were only constrained by occasional high external winds. This paper contrasts the in situ WEW method with closely related field-warming approaches using both aboveground (air or infrared heating) and belowground-warming methods. It also includes a full discussion of confounding factors that need to be considered carefully in the interpretation of experimental results. As a result, the WEW method combining aboveground and deep-soil heating approaches enables observations of future temperature conditions not available in the current observational record, and therefore provides a plausible glimpse of future environmental

  9. Attaining whole-ecosystem warming using air and deep-soil heating methods with an elevated CO2 atmosphere

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hanson, Paul J.; Riggs, Jeffery S.; Nettles, IV, W. Robert

    This paper describes the operational methods to achieve and measure both deep-soil heating (0–3 m) and whole-ecosystem warming (WEW) appropriate to the scale of tall-stature, high-carbon, boreal forest peatlands. The methods were developed to allow scientists to provide a plausible set of ecosystem-warming scenarios within which immediate and longer-term (1 decade) responses of organisms (microbes to trees) and ecosystem functions (carbon, water and nutrient cycles) could be measured. Elevated CO 2 was also incorporated to test how temperature responses may be modified by atmospheric CO 2 effects on carbon cycle processes. The WEW approach was successful in sustaining a widemore » range of aboveground and belowground temperature treatments (+0, +2.25, +4.5, +6.75 and +9 °C) in large 115 m 2 open-topped enclosures with elevated CO 2 treatments (+0 to +500 ppm). Air warming across the entire 10 enclosure study required ~90 % of the total energy for WEW ranging from 64 283 mega Joules (MJ) d –1 during the warm season to 80 102 MJ d –1 during cold months. Soil warming across the study required only 1.3 to 1.9 % of the energy used ranging from 954 to 1782 MJ d –1 of energy in the warm and cold seasons, respectively. The residual energy was consumed by measurement and communication systems. Sustained temperature and elevated CO 2 treatments were only constrained by occasional high external winds. This paper contrasts the in situ WEW method with closely related field-warming approaches using both aboveground (air or infrared heating) and belowground-warming methods. It also includes a full discussion of confounding factors that need to be considered carefully in the interpretation of experimental results. As a result, the WEW method combining aboveground and deep-soil heating approaches enables observations of future temperature conditions not available in the current observational record, and therefore provides a plausible glimpse of future environmental

  10. Seasonal sea ice cover during the warm Pliocene: Evidence from the Iceland Sea (ODP Site 907)

    NASA Astrophysics Data System (ADS)

    Clotten, Caroline; Stein, Ruediger; Fahl, Kirsten; De Schepper, Stijn

    2018-01-01

    Sea ice is a critical component in the Arctic and global climate system, yet little is known about its extent and variability during past warm intervals, such as the Pliocene (5.33-2.58 Ma). Here, we present the first multi-proxy (IP25, sterols, alkenones, palynology) sea ice reconstructions for the Late Pliocene Iceland Sea (ODP Site 907). Our interpretation of a seasonal sea ice cover with occasional ice-free intervals between 3.50-3.00 Ma is supported by reconstructed alkenone-based summer sea surface temperatures. As evidenced from brassicasterol and dinosterol, primary productivity was low between 3.50 and 3.00 Ma and the site experienced generally oligotrophic conditions. The East Greenland Current (and East Icelandic Current) may have transported sea ice into the Iceland Sea and/or brought cooler and fresher waters favoring local sea ice formation. Between 3.00 and 2.40 Ma, the Iceland Sea is mainly sea ice-free, but seasonal sea ice occurred between 2.81 and 2.74 Ma. Sea ice extending into the Iceland Sea at this time may have acted as a positive feedback for the build-up of the Greenland Ice Sheet (GIS), which underwent a major expansion ∼2.75 Ma. Thereafter, most likely a stable sea ice edge developed close to Greenland, possibly changing together with the expansion and retreat of the GIS and affecting the productivity in the Iceland Sea.

  11. Climate Change Across Seasons Experiment (CCASE): A new method for simulating future climate in seasonally snow-covered ecosystems.

    PubMed

    Templer, Pamela H; Reinmann, Andrew B; Sanders-DeMott, Rebecca; Sorensen, Patrick O; Juice, Stephanie M; Bowles, Francis; Sofen, Laura E; Harrison, Jamie L; Halm, Ian; Rustad, Lindsey; Martin, Mary E; Grant, Nicholas

    2017-01-01

    Climate models project an increase in mean annual air temperatures and a reduction in the depth and duration of winter snowpack for many mid and high latitude and high elevation seasonally snow-covered ecosystems over the next century. The combined effects of these changes in climate will lead to warmer soils in the growing season and increased frequency of soil freeze-thaw cycles (FTCs) in winter due to the loss of a continuous, insulating snowpack. Previous experiments have warmed soils or removed snow via shoveling or with shelters to mimic projected declines in the winter snowpack. To our knowledge, no experiment has examined the interactive effects of declining snowpack and increased frequency of soil FTCs, combined with soil warming in the snow-free season on terrestrial ecosystems. In addition, none have mimicked directly the projected increase in soil FTC frequency in tall statured forests that is expected as a result of a loss of insulating snow in winter. We established the Climate Change Across Seasons Experiment (CCASE) at Hubbard Brook Experimental Forest in the White Mountains of New Hampshire in 2012 to assess the combined effects of these changes in climate on a variety of pedoclimate conditions, biogeochemical processes, and ecology of northern hardwood forests. This paper demonstrates the feasibility of creating soil FTC events in a tall statured ecosystem in winter to simulate the projected increase in soil FTC frequency over the next century and combines this projected change in winter climate with ecosystem warming throughout the snow-free season. Together, this experiment provides a new and more comprehensive approach for climate change experiments that can be adopted in other seasonally snow-covered ecosystems to simulate expected changes resulting from global air temperature rise.

  12. Climate Change Across Seasons Experiment (CCASE): A new method for simulating future climate in seasonally snow-covered ecosystems

    PubMed Central

    Templer, Pamela H.; Reinmann, Andrew B.; Sanders-DeMott, Rebecca; Sorensen, Patrick O.; Juice, Stephanie M.; Bowles, Francis; Sofen, Laura E.; Harrison, Jamie L.; Halm, Ian; Rustad, Lindsey; Martin, Mary E.; Grant, Nicholas

    2017-01-01

    Climate models project an increase in mean annual air temperatures and a reduction in the depth and duration of winter snowpack for many mid and high latitude and high elevation seasonally snow-covered ecosystems over the next century. The combined effects of these changes in climate will lead to warmer soils in the growing season and increased frequency of soil freeze-thaw cycles (FTCs) in winter due to the loss of a continuous, insulating snowpack. Previous experiments have warmed soils or removed snow via shoveling or with shelters to mimic projected declines in the winter snowpack. To our knowledge, no experiment has examined the interactive effects of declining snowpack and increased frequency of soil FTCs, combined with soil warming in the snow-free season on terrestrial ecosystems. In addition, none have mimicked directly the projected increase in soil FTC frequency in tall statured forests that is expected as a result of a loss of insulating snow in winter. We established the Climate Change Across Seasons Experiment (CCASE) at Hubbard Brook Experimental Forest in the White Mountains of New Hampshire in 2012 to assess the combined effects of these changes in climate on a variety of pedoclimate conditions, biogeochemical processes, and ecology of northern hardwood forests. This paper demonstrates the feasibility of creating soil FTC events in a tall statured ecosystem in winter to simulate the projected increase in soil FTC frequency over the next century and combines this projected change in winter climate with ecosystem warming throughout the snow-free season. Together, this experiment provides a new and more comprehensive approach for climate change experiments that can be adopted in other seasonally snow-covered ecosystems to simulate expected changes resulting from global air temperature rise. PMID:28207766

  13. Modeling the Spatial and Temporal Variation of Monthly and Seasonal Precipitation on the Nevada Test Site and Vicinity, 1960-2006

    USGS Publications Warehouse

    Blainey, Joan B.; Webb, Robert H.; Magirl, Christopher S.

    2007-01-01

    The Nevada Test Site (NTS), located in the climatic transition zone between the Mojave and Great Basin Deserts, has a network of precipitation gages that is unusually dense for this region. This network measures monthly and seasonal variation in a landscape with diverse topography. Precipitation data from 125 climate stations on or near the NTS were used to spatially interpolate precipitation for each month during the period of 1960 through 2006 at high spatial resolution (30 m). The data were collected at climate stations using manual and/or automated techniques. The spatial interpolation method, applied to monthly accumulations of precipitation, is based on a distance-weighted multivariate regression between the amount of precipitation and the station location and elevation. This report summarizes the temporal and spatial characteristics of the available precipitation records for the period 1960 to 2006, examines the temporal and spatial variability of precipitation during the period of record, and discusses some extremes in seasonal precipitation on the NTS.

  14. Changes in the seasonality of Arctic sea ice and temperature

    NASA Astrophysics Data System (ADS)

    Bintanja, R.

    2012-04-01

    Observations show that the Arctic sea ice cover is currently declining as a result of climate warming. According to climate models, this retreat will continue and possibly accelerate in the near-future. However, the magnitude of this decline is not the same throughout the year. With temperatures near or above the freezing point, summertime Arctic sea ice will quickly diminish. However, at temperatures well below freezing, the sea ice cover during winter will exhibit a much weaker decline. In the future, the sea ice seasonal cycle will be no ice in summer, and thin one-year ice in winter. Hence, the seasonal cycle in sea ice cover will increase with ongoing climate warming. This in itself leads to an increased summer-winter contrast in surface air temperature, because changes in sea ice have a dominant influence on Arctic temperature and its seasonality. Currently, the annual amplitude in air temperature is decreasing, however, because winters warm faster than summer. With ongoing summer sea ice reductions there will come a time when the annual temperature amplitude will increase again because of the large seasonal changes in sea ice. This suggests that changes in the seasonal cycle in Arctic sea ice and temperature are closely, and intricately, connected. Future changes in Arctic seasonality (will) have an profound effect on flora, fauna, humans and economic activities.

  15. [Characteristics and adaptation of seasonal drought in southern China under the background of climate change. V. Seasonal drought characteristics division and assessment in southern China].

    PubMed

    Huang, Wan-Hua; Sui, Yue; Yang, Xiao-Guang; Dai, Shu-Wei; Li, Mao-Song

    2013-10-01

    Zoning seasonal drought based on the study of drought characteristics can provide theoretical basis for formulating drought mitigation plans and improving disaster reduction technologies in different arid zones under global climate change. Based on the National standard of meteorological drought indices and agricultural drought indices and the 1959-2008 meteorological data from 268 meteorological stations in southern China, this paper analyzed the climatic background and distribution characteristics of seasonal drought in southern China, and made a three-level division of seasonal drought in this region by the methods of combining comprehensive factors and main factors, stepwise screening indices, comprehensive disaster analysis, and clustering analysis. The first-level division was with the annual aridity index and seasonal aridity index as the main indices and with the precipitation during entire year and main crop growing season as the auxiliary indices, dividing the southern China into four primary zones, including semi-arid zone, sub-humid zone, humid zone, and super-humid zone. On this basis, the four primary zones were subdivided into nine second-level zones, including one semi-arid area-temperate-cold semi-arid hilly area in Sichuan-Yunnan Plateau, three sub-humid areas of warm sub-humid area in the north of the Yangtze River, warm-tropical sub-humid area in South China, and temperate-cold sub-humid plateau area in Southwest China, three humid areas of temperate-tropical humid area in the Yangtze River Basin, warm-tropical humid area in South China, and warm humid hilly area in Southwest China, and two super-humid areas of warm-tropical super-humid area in South China and temperate-cold super-humid hilly area in the south of the Yangtze River and Southwest China. According to the frequency and intensity of multiple drought indices, the second-level zones were further divided into 29 third-level zones. The distribution of each seasonal drought zone was

  16. Effects of Soil Warming and Nitrogen Addition on Soil Respiration in a New Zealand Tussock Grassland

    PubMed Central

    Graham, Scott L.; Hunt, John E.; Millard, Peter; McSeveny, Tony; Tylianakis, Jason M.; Whitehead, David

    2014-01-01

    Soil respiration (R S) represents a large terrestrial source of CO2 to the atmosphere. Global change drivers such as climate warming and nitrogen deposition are expected to alter the terrestrial carbon cycle with likely consequences for R S and its components, autotrophic (R A) and heterotrophic respiration (R H). Here we investigate the impacts of a 3°C soil warming treatment and a 50 kg ha−1 y−1 nitrogen addition treatment on R S, R H and their respective seasonal temperature responses in an experimental tussock grassland. Average respiration in untreated soils was 0.96±0.09 μmol m−2 s−1 over the course of the experiment. Soil warming and nitrogen addition increased R S by 41% and 12% respectively. These treatment effects were additive under combined warming and nitrogen addition. Warming increased R H by 37% while nitrogen addition had no effect. Warming and nitrogen addition affected the seasonal temperature response of R S by increasing the basal rate of respiration (R 10) by 14% and 20% respectively. There was no significant interaction between treatments for R 10. The treatments had no impact on activation energy (E 0). The seasonal temperature response of R H was not affected by either warming or nitrogen addition. These results suggest that the additional CO2 emissions from New Zealand tussock grassland soils as a result of warming-enhanced R S constitute a potential positive feedback to rising atmospheric CO2 concentration. PMID:24621790

  17. Five years of phenology observations from a mixed-grass prairie exposed to warming and elevated CO2.

    PubMed

    Reyes-Fox, Melissa; Steltzer, Heidi; LeCain, Daniel R; McMaster, Gregory S

    2016-10-11

    Atmospheric CO 2 concentrations have been steadily increasing since the Industrial Era and contribute to concurrent increases in global temperatures. Many observational studies suggest climate warming alone contributes to a longer growing season. To determine the relative effect of warming on plant phenology, we investigated the individual and joint effects of warming and CO 2 enrichment on a mixed-grass prairie plant community by following the development of six common grassland species and recording four major life history events. Our data support that, in a semi-arid system, while warming advances leaf emergence and flower production, it also expedites seed maturation and senescence at the species level. However, the additive effect can be an overall lengthening of the growing and reproductive seasons since CO 2 enrichment, particularly when combined with warming, contributed to a longer growing season by delaying plant maturation and senescence. Fostering synthesis across multiple phenology datasets and identifying key factors affecting plant phenology will be vital for understanding regional plant community responses to climate change.

  18. Five years of phenology observations from a mixed-grass prairie exposed to warming and elevated CO2

    PubMed Central

    Reyes-Fox, Melissa; Steltzer, Heidi; LeCain, Daniel R.; McMaster, Gregory S.

    2016-01-01

    Atmospheric CO2 concentrations have been steadily increasing since the Industrial Era and contribute to concurrent increases in global temperatures. Many observational studies suggest climate warming alone contributes to a longer growing season. To determine the relative effect of warming on plant phenology, we investigated the individual and joint effects of warming and CO2 enrichment on a mixed-grass prairie plant community by following the development of six common grassland species and recording four major life history events. Our data support that, in a semi-arid system, while warming advances leaf emergence and flower production, it also expedites seed maturation and senescence at the species level. However, the additive effect can be an overall lengthening of the growing and reproductive seasons since CO2 enrichment, particularly when combined with warming, contributed to a longer growing season by delaying plant maturation and senescence. Fostering synthesis across multiple phenology datasets and identifying key factors affecting plant phenology will be vital for understanding regional plant community responses to climate change. PMID:27727235

  19. Increased wintertime CO2 loss as a result of sustained tundra warming

    NASA Astrophysics Data System (ADS)

    Webb, Elizabeth E.; Schuur, Edward A. G.; Natali, Susan M.; Oken, Kiva L.; Bracho, Rosvel; Krapek, John P.; Risk, David; Nickerson, Nick R.

    2016-02-01

    Permafrost soils currently store approximately 1672 Pg of carbon (C), but as high latitudes warm, this temperature-protected C reservoir will become vulnerable to higher rates of decomposition. In recent decades, air temperatures in the high latitudes have warmed more than any other region globally, particularly during the winter. Over the coming century, the arctic winter is also expected to experience the most warming of any region or season, yet it is notably understudied. Here we present nonsummer season (NSS) CO2 flux data from the Carbon in Permafrost Experimental Heating Research project, an ecosystem warming experiment of moist acidic tussock tundra in interior Alaska. Our goals were to quantify the relationship between environmental variables and winter CO2 production, account for subnivean photosynthesis and late fall plant C uptake in our estimate of NSS CO2 exchange, constrain NSS CO2 loss estimates using multiple methods of measuring winter CO2 flux, and quantify the effect of winter soil warming on total NSS CO2 balance. We measured CO2 flux using four methods: two chamber techniques (the snow pit method and one where a chamber is left under the snow for the entire season), eddy covariance, and soda lime adsorption, and found that NSS CO2 loss varied up to fourfold, depending on the method used. CO2 production was dependent on soil temperature and day of season but atmospheric pressure and air temperature were also important in explaining CO2 diffusion out of the soil. Warming stimulated both ecosystem respiration and productivity during the NSS and increased overall CO2 loss during this period by 14% (this effect varied by year, ranging from 7 to 24%). When combined with the summertime CO2 fluxes from the same site, our results suggest that this subarctic tundra ecosystem is shifting away from its historical function as a C sink to a C source.

  20. Extreme warm temperatures alter forest phenology and productivity in Europe.

    PubMed

    Crabbe, Richard A; Dash, Jadu; Rodriguez-Galiano, Victor F; Janous, Dalibor; Pavelka, Marian; Marek, Michal V

    2016-09-01

    Recent climate warming has shifted the timing of spring and autumn vegetation phenological events in the temperate and boreal forest ecosystems of Europe. In many areas spring phenological events start earlier and autumn events switch between earlier and later onset. Consequently, the length of growing season in mid and high latitudes of European forest is extended. However, the lagged effects (i.e. the impact of a warm spring or autumn on the subsequent phenological events) on vegetation phenology and productivity are less explored. In this study, we have (1) characterised extreme warm spring and extreme warm autumn events in Europe during 2003-2011, and (2) investigated if direct impact on forest phenology and productivity due to a specific warm event translated to a lagged effect in subsequent phenological events. We found that warmer events in spring occurred extensively in high latitude Europe producing a significant earlier onset of greening (OG) in broadleaf deciduous forest (BLDF) and mixed forest (MF). However, this earlier OG did not show any significant lagged effects on autumnal senescence. Needleleaf evergreen forest (NLEF), BLDF and MF showed a significantly delayed end of senescence (EOS) as a result of extreme warm autumn events; and in the following year's spring phenological events, OG started significantly earlier. Extreme warm spring events directly led to significant (p=0.0189) increases in the productivity of BLDF. In order to have a complete understanding of ecosystems response to warm temperature during key phenological events, particularly autumn events, the lagged effect on the next growing season should be considered. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Microbial Community Activity is Insensitive to Passive Warming in a Semiarid Ecosystem

    NASA Astrophysics Data System (ADS)

    Espinosa, N. J.; Gallery, R. E.; Fehmi, J. S.

    2016-12-01

    Soil microorganisms drive ecosystem nutrient cycling through the production of extracellular enzymes, which facilitate organic matter decomposition, and the flux of large amounts of carbon dioxide to the atmosphere. Although aird and semiarid ecosystems occupy over 40% of land cover and are projected to expand due to climate change, much of our current understanding of these processes comes from mesic temperate ecosystems. Semiarid ecosystems have added complexity due to the widespread biological adaptations to infrequent and discreet precipitation pulses, which enable biological activity to persist throughout dry periods and thrive following seasonal precipitation events. Additionally, the intricacies of plant-microbe interactions and the response of these interactions to a warmer climate and increased precipitation variability in semiarid ecosystems present a continued challenge for climate change research. In this study, we used a passive warming experiment with added plant debris as either woodchip or biochar, to simulate different long-term carbon additions to two common semiarid soils. The response of soil respiration, plant biomass, and microbial activity was monitored bi-annually. We hypothesized that microbial activity would increase with temperature manipulations when soil moisture limitation was alleviated by summer precipitation. The passive warming treatment was most pronounced during periods of daily and seasonal temperature maxima. For all seven hydrolytic enzymes examined, there was no significant response to experimental warming, regardless of seasonal climatic and soil moisture variation. Surprisingly, soil respiration responded positively to warming for certain carbon additions and seasons, which did not correspond with a similar response in plant biomass. The enzyme results observed here are consistent with the few other experimental results for warming in semiarid ecosystems and indicate that the soil microbial community activity of semiarid

  2. Seasonally asymmetric enhancement of northern vegetation productivity

    NASA Astrophysics Data System (ADS)

    Park, T.; Myneni, R.

    2017-12-01

    Multiple evidences of widespread greening and increasing terrestrial carbon uptake have been documented. In particular, enhanced gross productivity of northern vegetation has been a critical role leading to observed carbon uptake trend. However, seasonal photosynthetic activity and its contribution to observed annual carbon uptake trend and interannual variability are not well understood. Here, we introduce a multiple-source of datasets including ground, atmospheric and satellite observations, and multiple process-based global vegetation models to understand how seasonal variation of land surface vegetation controls a large-scale carbon exchange. Our analysis clearly shows a seasonally asymmetric enhancement of northern vegetation productivity in growing season during last decades. Particularly, increasing gross productivity in late spring and early summer is obvious and dominant driver explaining observed trend and variability. We observe more asymmetric productivity enhancement in warmer region and this spatially varying asymmetricity in northern vegetation are likely explained by canopy development rate, thermal and light availability. These results imply that continued warming may facilitate amplifying asymmetric vegetation activity and cause these trends to become more pervasive, in turn warming induced regime shift in northern land.

  3. Carbon balance of a subarctic meadow under 3 r{ C warming - unravelling respiration}

    NASA Astrophysics Data System (ADS)

    Silvennoinen, Hanna; Bárcena, Téresa G.; Moni, Christophe; Szychowski, Marcin; Rajewicz, Paulina; Höglind, Mats; Rasse, Daniel P.

    2016-04-01

    Boreal and arctic terrestrial ecosystems are central to the climate change debate, as the warming is expected to be disproportionate as compared to world averages. Northern areas contain large terrestrial carbon (C) stocks further increasing the interest in the C cycle's fate in changing climate. In 2013, we started an ecosystem warming experiment at a meadow in Eastern Finnmark, NE Norway. The meadow was on a clay soil and its vegetation was common meadow grasses and clover. Typical local agronomy was applied. The study site featured ten 4m-wide hexagonal plots, five control and five actively warmed plots in randomized complete block design. Each of the warmed plots was continuously maintained 3 ° C above its associated control plot with infrared heaters controlled by canopy thermal sensors. In 2014-2015, we measured net ecosystem exchange (NEE) and respiration twice per week during growth seasons from preinstalled collars of each site with dynamic, temperature-controlled chambers combined to an infrared analyzer. Despite warming-induced differences in yield, species composition and root biomass, neither the NEE nor the respiration responded to the warming, all sites remaining equal sinks for C. Following this observation, we carried out an additional experiment in 2015 where we aimed at partitioning the total CO2 flux to microbial and plant respiration as well as at recording the growth season variation of those parameters in situ. Here, we used an approach based on natural abundances of 13C. The δ13C signature of both autotrophic plant respiration and heterotrophic microbial respiration were obtained in targeted incubations (Snell et al. 2014). Then, the δ13C -signature of the total soil respiration was determined in the field by Keeling approach with dynamic dark chambers combined to CRDS. Proportions of autotrophic and heterotrophic components in total soil respiration were then derived based on 13C mixing model. Incubations were repeated at early, mid and

  4. Intake, digestibility, and nitrogen retention by sheep supplemented with warm-season legume haylages or soybean meal.

    PubMed

    Foster, J L; Adesogan, A T; Carter, J N; Blount, A R; Myer, R O; Phatak, S C

    2009-09-01

    The high cost of commercial supplements necessitates evaluation of alternatives for ruminant livestock fed poor quality warm-season grasses. This study determined how supplementing bahiagrass haylage (Paspalum notatum Flügge cv. Tifton 9) with soybean [Glycine max (L.) Merr.] meal or warm-season legume haylages affected the performance of lambs. Forty-two Dorper x Katadhin lambs (27.5 +/- 5 kg) were fed for ad libitum intake of bahiagrass haylage (67.8% NDF, 9.6% CP) alone (control) or supplemented with soybean meal (18.8% NDF, 51.4% CP) or haylages of annual peanut [Arachis hypogaea (L.) cv. Florida MDR98; 39.6% NDF, 18.7% CP], cowpea [Vigna unguiculata (L.) Walp. cv. Iron clay; 44.1% NDF, 16.0% CP], perennial peanut (Arachis glabrata Benth. cv. Florigraze; 40.0% NDF, 15.8% CP), or pigeonpea [Cajanus cajan (L.) Millsp. cv. GA-2; 65.0% NDF, 13.7% CP]. Haylages were harvested at the optimal maturity for maximizing yield and nutritive value, wilted to 45% DM, baled, wrapped in polyethylene plastic, and ensiled for 180 d. Legumes were fed at 50% of the dietary DM, and soybean meal was fed at 8% of the dietary DM to match the average CP concentration (12.8%) of legume haylage-supplemented diets. Lambs were fed each diet for a 14-d adaptation period and a 7-d data collection period. Each diet was fed to 7 lambs in period 1 and 4 lambs in period 2. Pigeonpea haylage supplementation decreased (P < 0.01) DM and OM intake and digestibility vs. controls. Other legume haylages increased (P < 0.05) DM and OM intake vs. controls; however, only soybean meal supplementation increased (P = 0.01) DM digestibility. All supplements decreased (P = 0.05) NDF digestibility. Except for pigeonpea haylage, all supplements increased (P < 0.01) N intake, digestibility, and retention, and the responses were greatest (P = 0.04) with soybean meal supplementation. Microbial N synthesis was reduced (P = 0.02) by pigeonpea haylage supplementation, but unaffected (P = 0.05) by other supplements

  5. Effects of warming and nitrogen fertilization on GHG flux in the permafrost region of an alpine meadow

    NASA Astrophysics Data System (ADS)

    Chen, Xiaopeng; Wang, Genxu; Zhang, Tao; Mao, Tianxu; Wei, Da; Hu, Zhaoyong; Song, Chunlin

    2017-05-01

    The limited number of in situ measurements of greenhouse gas (GHG) flux during soil freeze-thaw cycles in permafrost regions limits our ability to accurately predict how the alpine ecosystem carbon sink or source function will vary under future warming and increased nitrogen (N) deposition. An alpine meadow in the permafrost region of the Qinghai-Tibet Plateau was selected, and a simulated warming with N fertilization experiment was carried out to investigate the key GHG fluxes (ecosystem respiration [Re], CH4 and N2O) in the early (EG), mid (MG) and late (LG) growing seasons. The results showed that: (i) warming (4.5 °C) increased the average seasonal Re, CH4 uptake and N2O emission by 73.5%, 65.9% and 431.6%, respectively. N fertilization (4 g N m-2) alone had no significant effect on GHG flux; the interaction of warming and N fertilization enhanced CH4 uptake by 10.3% and N2O emissions by 27.2% than warming, while there was no significant effect on the Re; (ii) the average seasonal fluxes of Re, CH4 and N2O were MG > LG > EG, and Re and CH4 uptake were most sensitive to the soil freezing process instead of soil thawing process; (iii) surface soil temperature was the main driving factor of the Re and CH4 fluxes, and the N2O flux was mainly affected by daily rainfall; (iv) in the growing season, warming increased greenhouse warming potential (GWP) of the alpine meadow by 74.5%, the N fertilization decreased GWP of the warming plots by 13.9% but it was not statistically significant. These results indicate that (i) relative to future climate warming (or permafrost thawing), there could be a hysteresis of GHG flux in the alpine meadow of permafrost region; (ii) under the scenario of climate warming, increasing N deposition has limited impacts on the feedback of GHG flux of the alpine meadow.

  6. The origins of the anomalous warming in the California coastal ocean and San Francisco Bay during 2014-2016

    NASA Astrophysics Data System (ADS)

    Chao, Yi; Farrara, John D.; Bjorkstedt, Eric; Chai, Fei; Chavez, Francisco; Rudnick, Daniel L.; Enright, Wendy; Fisher, Jennifer L.; Peterson, William T.; Welch, Gregory F.; Davis, Curtiss O.; Dugdale, Richard C.; Wilkerson, Frances P.; Zhang, Hongchun; Zhang, Yinglong; Ateljevich, Eli

    2017-09-01

    During 2014 exceptionally warm water temperatures developed across a wide area off the California coast and within San Francisco Bay (SFB) and persisted into 2016. Observations and numerical model output are used to document this warming and determine its origins. The coastal warming was mostly confined to the upper 100 m of the ocean and was manifested strongly in the two leading modes of upper ocean (0-100 m) temperature variability in the extratropical eastern Pacific. Observations suggest that the coastal warming in 2014 propagated into nearshore regions from the west while later indicating a warming influence that propagated from south to north into the region associated with the 2015-2016 El Niño event. An analysis of the upper ocean (0-100 m) heat budget in a Regional Ocean Modeling System (ROMS) simulation confirmed this scenario. The results from a set of sensitivity runs with the model in which the lateral boundary conditions varied supported the conclusions drawn from the heat budget analysis. Concerning the warming in the SFB, an examination of the observations and the heat budget in an unstructured-grid numerical model simulation suggested that the warming during the second half of 2014 and early 2016 originated in the adjacent California coastal ocean and propagated through the Golden Gate into the Bay. The finding that the coastal and Bay warming are due to the relatively slow propagation of signals from remote sources raises the possibility that such warming events may be predictable many months or even several seasons in advance.

  7. The Historical Context of the 2017 Hurricane Season's Ocean Warmth

    NASA Astrophysics Data System (ADS)

    Jacobs, P.; Akella, S.; Trenberth, K. E.; Lijing, C.; Abraham, J. P.

    2017-12-01

    Public discussion of the unusually active 2017 North Atlantic Hurricane Season quickly focused on the role of sea surface temperatures (SSTs) in the North Atlantic. Some meteorologists characterized them as near-normal, while climate-focused voices tended to characterize them as warmer than average, placing them in the context of anthropogenic warming. Much of this divergence in views can be explained by the relatively recent, relatively warm baseline (1981-2010) used for daily SST information, such as provided by OISSTv2. Longer term records of SSTs, such as HadISST, HadSST, and ERSST only attempt to provide monthly averages, while tropical cyclones have lifetimes on the timescale of days. Further, hurricanes create a cold wake which can impact storm movement and intensity, as well as subsequent storms, but is gradually wiped out by the sun. This process is further complicated by the role of ocean heat content (OHC), an increase in which can mitigate the impact of upwelled water. Here we examine the statistical characteristics of daily SSTs and OHC during the satellite record, including their temporal autocorrelation, and use this information in conjunction with longer term monthly records to bound what we can and cannot confidently say about the longer term historical context of the storms Harvey, Irma, and Maria.

  8. Autumn photosynthetic decline and growth cessation in seedlings of white spruce are decoupled under warming and photoperiod manipulations.

    PubMed

    Stinziano, Joseph R; Way, Danielle A

    2017-08-01

    Climate warming is expected to increase the seasonal duration of photosynthetic carbon fixation and tree growth in high-latitude forests. However, photoperiod, a crucial cue for seasonality, will remain constant, which may constrain tree responses to warming. We investigated the effects of temperature and photoperiod on weekly changes in photosynthetic capacity, leaf biochemistry and growth in seedlings of a boreal evergreen conifer, white spruce [Picea glauca (Moench) Voss]. Warming delayed autumn declines in photosynthetic capacity, extending the period when seedlings had high carbon uptake. While photoperiod was correlated with photosynthetic capacity, short photoperiods did not constrain the maintenance of high photosynthetic capacity under warming. Rubisco concentration dynamics were affected by temperature but not photoperiod, while leaf pigment concentrations were unaffected by treatments. Respiration rates at 25 °C were stimulated by photoperiod, although respiration at the growth temperatures was increased in warming treatments. Seedling growth was stimulated by increased photoperiod and suppressed by warming. We demonstrate that temperature is a stronger control on the seasonal timing of photosynthetic down-regulation than is photoperiod. Thus, while warming can stimulate carbon uptake in boreal conifers, the extra carbon may be directed towards respiration rather than biomass, potentially limiting carbon sequestration under climate change. © 2017 John Wiley & Sons Ltd.

  9. Using radiative signatures to diagnose the cause of warming during the 2013-2014 Californian drought

    NASA Astrophysics Data System (ADS)

    Wolf, Sebastian; Yin, Dongqin; Roderick, Michael L.

    2017-10-01

    California recently experienced among the worst droughts of the last century, with exceptional precipitation deficits and co-occurring record high temperatures. The dry conditions caused severe water shortages in one of the economically most important agricultural regions of the US. It has recently been hypothesized that anthropogenic warming is increasing the likelihood of such extreme droughts in California, or more specifically, that warmer temperatures from the enhanced greenhouse effect intensify drought conditions. However, separating the cause and effect is difficult because the dry conditions lead to a reduction in evaporative cooling that contributes to the warming. Here we investigate and compare the forcing of long-term greenhouse-induced warming with the short-term warming during the 2013-2014 Californian drought. We use the concept of radiative signatures to investigate the source of the radiative perturbation during the drought, relate the signatures to expected changes due to anthropogenic warming, and assess the cause of warming based on observed changes in the surface energy balance compared to the period 2001-2012. We found that the recent meteorological drought based on precipitation deficits was characterised by an increase in incoming shortwave radiation coupled with a decline in incoming longwave radiation, which contributed to record warm temperatures. In contrast, climate models project that anthropogenic warming is accompanied by little change in incoming shortwave but a large increase in incoming longwave radiation. The warming during the drought was associated with increased incoming shortwave radiation in combination with reduced evaporative cooling from water deficits, which enhanced surface temperatures and sensible heat transfer to the atmosphere. Our analyses demonstrate that radiative signatures are a powerful tool to differentiate the source of perturbations in the surface energy balance at monthly to seasonal time scales.

  10. Environmental Humidity Regulates Effects of Experimental Warming on Vegetation Index and Biomass Production in an Alpine Meadow of the Northern Tibet

    PubMed Central

    Fu, Gang; Shen, Zhen Xi

    2016-01-01

    Uncertainty about responses of vegetation index, aboveground biomass (AGB) and gross primary production (GPP) limits our ability to predict how climatic warming will influence plant growth in alpine regions. A field warming experiment was conducted in an alpine meadow at a low (4313 m), mid- (4513 m) and high elevation (4693 m) in the Northern Tibet since May 2010. Growing season vapor pressure deficit (VPD), soil temperature (Ts) and air temperature (Ta) decreased with increasing elevation, while growing season precipitation, soil moisture (SM), normalized difference vegetation index (NDVI), soil adjusted vegetation index (SAVI), AGB and GPP increased with increasing elevation. The growing season Ta, Ts and VPD in 2015 was greater than that in 2014, while the growing season precipitation, SM, NDVI, SAVI, AGB and GPP in 2015 was lower than that in 2014, respectively. Compared to the mean air temperature and precipitation during the growing season in 1963–2015, it was a warmer and wetter year in 2014 and a warmer and drier year in 2015. Experimental warming increased growing season Ts, Ta,VPD, but decreased growing season SM in 2014–2015 at all the three elevations. Experimental warming only reduced growing season NDVI, SAVI, AGB and GPP at the low elevation in 2015. Growing season NDVI, SAVI, AGB and GPP increased with increasing SM and precipitation, but decreased with increasing VPD, indicating vegetation index and biomass production increased with environmental humidity. The VPD explained more variation of growing season NDVI, SAVI, AGB and GPP compared to Ts, Ta and SM at all the three elevations. Therefore, environmental humidity regulated the effect of experimental warming on vegetation index and biomass production in alpine meadows on the Tibetan Plateau. PMID:27798690

  11. C4 grasses prosper as carbon dioxide eliminates desiccation in warmed semi-arid grassland.

    PubMed

    Morgan, Jack A; LeCain, Daniel R; Pendall, Elise; Blumenthal, Dana M; Kimball, Bruce A; Carrillo, Yolima; Williams, David G; Heisler-White, Jana; Dijkstra, Feike A; West, Mark

    2011-08-03

    Global warming is predicted to induce desiccation in many world regions through increases in evaporative demand. Rising CO(2) may counter that trend by improving plant water-use efficiency. However, it is not clear how important this CO(2)-enhanced water use efficiency might be in offsetting warming-induced desiccation because higher CO(2) also leads to higher plant biomass, and therefore greater transpirational surface. Furthermore, although warming is predicted to favour warm-season, C(4) grasses, rising CO(2) should favour C(3), or cool-season plants. Here we show in a semi-arid grassland that elevated CO(2) can completely reverse the desiccating effects of moderate warming. Although enrichment of air to 600 p.p.m.v. CO(2) increased soil water content (SWC), 1.5/3.0 °C day/night warming resulted in desiccation, such that combined CO(2) enrichment and warming had no effect on SWC relative to control plots. As predicted, elevated CO(2) favoured C(3) grasses and enhanced stand productivity, whereas warming favoured C(4) grasses. Combined warming and CO(2) enrichment stimulated above-ground growth of C(4) grasses in 2 of 3 years when soil moisture most limited plant productivity. The results indicate that in a warmer, CO(2)-enriched world, both SWC and productivity in semi-arid grasslands may be higher than previously expected.

  12. Are Sierran Lakes Warming as a Result of Climate Change? The Effects of Climate Warming and Variation in Precipitation on Water Temperature in a Snowmelt-Dominated Lake

    NASA Astrophysics Data System (ADS)

    Sadro, S.; Melack, J. M.; Sickman, J. O.; Skeen, K.

    2016-12-01

    Water temperature regulates a broad range of fundamental ecosystem processes in lakes. While climate can be an important factor regulating lake temperatures, heterogeneity in the warming response of lakes is large, and variation in precipitation is rarely considered. We analyzed three decades of climate and water temperature data from a high-elevation catchment in the southern Sierra Nevada of California to illustrate the magnitude of warming taking place during different seasons and the role of precipitation in regulating lake temperatures. Significant climate warming trends were evident during all seasons except spring. Nighttime rates of climate warming were approximately 25% higher than daytime rates. Spatial patterns in warming were elevation dependent, with rates of temperature increase higher at sites above 2800 m.a.s.l. than below. Although interannual variation in snow deposition was high, the frequency and severity of recent droughts has contributed to a significant 3.4 mm year -1 decline in snow water equivalent over the last century. Snow accumulation, more than any other climate factor, regulated lake temperature; 94% of variation in summer lake temperature was regulated by precipitation as snow. For every 100 mm decrease in snow water equivalent there was a 0.62 ° increase in lake temperature. Drought years amplify warming in lakes by reducing the role of cold spring meltwaters in lake energy budgets and prolonging the ice-free period during which lakes warm. The combination of declining winter snowpack and warming air temperatures has the capacity to amplify the effect of climate warming on lake temperatures during drought years. Interactions among climatic factors need to be considered when evaluating ecosystem level effects, especially in mountain regions. For mountain lakes already affected by drought, continued climate warming during spring and autumn has the greatest potential to impact mean lake temperatures.

  13. Global metabolic impacts of recent climate warming.

    PubMed

    Dillon, Michael E; Wang, George; Huey, Raymond B

    2010-10-07

    Documented shifts in geographical ranges, seasonal phenology, community interactions, genetics and extinctions have been attributed to recent global warming. Many such biotic shifts have been detected at mid- to high latitudes in the Northern Hemisphere-a latitudinal pattern that is expected because warming is fastest in these regions. In contrast, shifts in tropical regions are expected to be less marked because warming is less pronounced there. However, biotic impacts of warming are mediated through physiology, and metabolic rate, which is a fundamental measure of physiological activity and ecological impact, increases exponentially rather than linearly with temperature in ectotherms. Therefore, tropical ectotherms (with warm baseline temperatures) should experience larger absolute shifts in metabolic rate than the magnitude of tropical temperature change itself would suggest, but the impact of climate warming on metabolic rate has never been quantified on a global scale. Here we show that estimated changes in terrestrial metabolic rates in the tropics are large, are equivalent in magnitude to those in the north temperate-zone regions, and are in fact far greater than those in the Arctic, even though tropical temperature change has been relatively small. Because of temperature's nonlinear effects on metabolism, tropical organisms, which constitute much of Earth's biodiversity, should be profoundly affected by recent and projected climate warming.

  14. Mapping the Impact of Aerosol-Cloud Interactions on Cloud Formation and Warm-season Rainfall in Mountainous Regions Using Observations and Models

    NASA Astrophysics Data System (ADS)

    Duan, Yajuan

    Light rainfall (< 3 mm/hr) amounts to 30-70% of the annual water budget in the Southern Appalachian Mountains (SAM), a mid-latitude mid-mountain system in the SE CONUS. Topographic complexity favors the diurnal development of regional-scale convergence patterns that provide the moisture source for low-level clouds and fog (LLCF). Low-level moisture and cloud condensation nuclei (CCN) are distributed by ridge-valley circulations favoring LLCF formation that modulate the diurnal cycle of rainfall especially the mid-day peak. The overarching objective of this dissertation is to advance the quantitative understanding of the indirect effect of aerosols on the diurnal cycle of LLCF and warm-season precipitation in mountainous regions generally, and in the SAM in particular, for the purpose of improving the representation of orographic precipitation processes in remote sensing retrievals and physically-based models. The research approach consists of integrating analysis of in situ observations from long-term observation networks and an intensive field campaign, multi-sensor satellite data, and modeling studies. In the first part of this dissertation, long-term satellite observations are analyzed to characterize the spatial and temporal variability of LLCF and to elucidate the physical basis of the space-time error structure in precipitation retrievals. Significantly underestimated precipitation errors are attributed to variations in low-level rainfall microstructure undetected by satellites. Column model simulations including observed LLCF microphysics demonstrate that seeder-feeder interactions (SFI) among upper-level precipitation and LLCF contribute to an three-fold increase in observed rainfall accumulation and can enhance surface rainfall by up to ten-fold. The second part of this dissertation examines the indirect effect of aerosols on cloud formation and warm-season daytime precipitation in the SAM. A new entraining spectral cloud parcel model was developed and

  15. Effects of global warming on ancient mammalian communities and their environments.

    PubMed

    DeSantis, Larisa R G; Feranec, Robert S; MacFadden, Bruce J

    2009-06-03

    Current global warming affects the composition and dynamics of mammalian communities and can increase extinction risk; however, long-term effects of warming on mammals are less understood. Dietary reconstructions inferred from stable isotopes of fossil herbivorous mammalian tooth enamel document environmental and climatic changes in ancient ecosystems, including C(3)/C(4) transitions and relative seasonality. Here, we use stable carbon and oxygen isotopes preserved in fossil teeth to document the magnitude of mammalian dietary shifts and ancient floral change during geologically documented glacial and interglacial periods during the Pliocene (approximately 1.9 million years ago) and Pleistocene (approximately 1.3 million years ago) in Florida. Stable isotope data demonstrate increased aridity, increased C(4) grass consumption, inter-faunal dietary partitioning, increased isotopic niche breadth of mixed feeders, niche partitioning of phylogenetically similar taxa, and differences in relative seasonality with warming. Our data show that global warming resulted in dramatic vegetation and dietary changes even at lower latitudes (approximately 28 degrees N). Our results also question the use of models that predict the long term decline and extinction of species based on the assumption that niches are conserved over time. These findings have immediate relevance to clarifying possible biotic responses to current global warming in modern ecosystems.

  16. Monthly Rainfall Erosivity Assessment for Switzerland

    NASA Astrophysics Data System (ADS)

    Schmidt, Simon; Meusburger, Katrin; Alewell, Christine

    2016-04-01

    Water erosion is crucially controlled by rainfall erosivity, which is quantified out of the kinetic energy of raindrop impact and associated surface runoff. Rainfall erosivity is often expressed as the R-factor in soil erosion risk models like the Universal Soil Loss Equation (USLE) and its revised version (RUSLE). Just like precipitation, the rainfall erosivity of Switzerland has a characteristic seasonal dynamic throughout the year. This inter-annual variability is to be assessed by a monthly and seasonal modelling approach. We used a network of 86 precipitation gauging stations with a 10-minute temporal resolution to calculate long-term average monthly R-factors. Stepwise regression and Monte Carlo Cross Validation (MCCV) was used to select spatial covariates to explain the spatial pattern of R-factor for each month across Switzerland. The regionalized monthly R-factor is mapped by its individual regression equation and the ordinary kriging interpolation of its residuals (Regression-Kriging). As covariates, a variety of precipitation indicator data has been included like snow height, a combination of hourly gauging measurements and radar observations (CombiPrecip), mean monthly alpine precipitation (EURO4M-APGD) and monthly precipitation sums (Rhires). Topographic parameters were also significant explanatory variables for single months. The comparison of all 12 monthly rainfall erosivity maps showed seasonality with highest rainfall erosivity in summer (June, July, and August) and lowest rainfall erosivity in winter months. Besides the inter-annual temporal regime, a seasonal spatial variability was detectable. Spatial maps of monthly rainfall erosivity are presented for the first time for Switzerland. The assessment of the spatial and temporal dynamic behaviour of the R-factor is valuable for the identification of more susceptible seasons and regions as well as for the application of selective erosion control measures. A combination with monthly vegetation

  17. Estimating annual high-flow statistics and monthly and seasonal low-flow statistics for ungaged sites on streams in Alaska and conterminous basins in Canada

    USGS Publications Warehouse

    Wiley, Jeffrey B.; Curran, Janet H.

    2003-01-01

    Methods for estimating daily mean flow-duration statistics for seven regions in Alaska and low-flow frequencies for one region, southeastern Alaska, were developed from daily mean discharges for streamflow-gaging stations in Alaska and conterminous basins in Canada. The 15-, 10-, 9-, 8-, 7-, 6-, 5-, 4-, 3-, 2-, and 1-percent duration flows were computed for the October-through-September water year for 222 stations in Alaska and conterminous basins in Canada. The 98-, 95-, 90-, 85-, 80-, 70-, 60-, and 50-percent duration flows were computed for the individual months of July, August, and September for 226 stations in Alaska and conterminous basins in Canada. The 98-, 95-, 90-, 85-, 80-, 70-, 60-, and 50-percent duration flows were computed for the season July-through-September for 65 stations in southeastern Alaska. The 7-day, 10-year and 7-day, 2-year low-flow frequencies for the season July-through-September were computed for 65 stations for most of southeastern Alaska. Low-flow analyses were limited to particular months or seasons in order to omit winter low flows, when ice effects reduce the quality of the records and validity of statistical assumptions. Regression equations for estimating the selected high-flow and low-flow statistics for the selected months and seasons for ungaged sites were developed from an ordinary-least-squares regression model using basin characteristics as independent variables. Drainage area and precipitation were significant explanatory variables for high flows, and drainage area, precipitation, mean basin elevation, and area of glaciers were significant explanatory variables for low flows. The estimating equations can be used at ungaged sites in Alaska and conterminous basins in Canada where streamflow regulation, streamflow diversion, urbanization, and natural damming and releasing of water do not affect the streamflow data for the given month or season. Standard errors of estimate ranged from 15 to 56 percent for high-duration flow

  18. Experimental winter warming modifies thermal performance and primes acorn ants for warm weather.

    PubMed

    MacLean, Heidi J; Penick, Clint A; Dunn, Robert R; Diamond, Sarah E

    2017-07-01

    The frequency of warm winter days is increasing under global climate change, but how organisms respond to warmer winters is not well understood. Most studies focus on growing season responses to warming. Locomotor performance is often highly sensitive to temperature, and can determine fitness outcomes through a variety of mechanisms including resource acquisition and predator escape. As a consequence, locomotor performance, and its impacts on fitness, may be strongly affected by winter warming in winter-active species. Here we use the acorn ant, Temnothorax curvispinosus, to explore how thermal performance (temperature-driven plasticity) in running speed is influenced by experimental winter warming of 3-5°C above ambient in a field setting. We used running speed as a measure of performance as it is a common locomotor trait that influences acquisition of nest sites and food in acorn ants. Experimental winter warming significantly altered thermal performance for running speed at high (26 and 36°C) but not low test temperatures (6 and 16°C). Although we saw little differentiation in thermal performance at cooler test temperatures, we saw a marked increase in running speed at the hotter test temperatures for ants that experienced warmer winters compared with those that experienced cooler winters. Our results provide evidence that overwintering temperatures can substantially influence organismal performance, and suggest that we cannot ignore overwintering effects when forecasting organismal responses to environmental changes in temperature. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Seasonal heterogeneity of ocean warming: a mortality sink for ectotherm colonizers

    PubMed Central

    Maffucci, Fulvio; Corrado, Raffaele; Palatella, Luigi; Borra, Marco; Marullo, Salvatore; Hochscheid, Sandra; Lacorata, Guglielmo; Iudicone, Daniele

    2016-01-01

    Distribution shifts are a common adaptive response of marine ectotherms to climate change but the pace of redistribution depends on species-specific traits that may promote or hamper expansion to northern habitats. Here we show that recently, the loggerhead turtle (Caretta caretta) has begun to nest steadily beyond the northern edge of the species’ range in the Mediterranean basin. This range expansion is associated with a significant warming of spring and summer sea surface temperature (SST) that offers a wider thermal window suitable for nesting. However, we found that post-hatchlings departing from this location experience low winter SST that may affect their survival and thus hamper the stabilization of the site by self-recruitment. The inspection of the Intergovernmental Panel on Climate Change model projections and observational data on SST trends shows that, despite the annual warming for this century, winter SST show little or no trends. Therefore, thermal constraints during the early developmental phase may limit the chance of population growth at this location also in the near future, despite increasingly favourable conditions at the nesting sites. Quantifying and understanding the interplay between dispersal and environmental changes at all life stages is critical for predicting ectotherm range expansion with climate warming. PMID:27044321

  20. Seasonal heterogeneity of ocean warming: a mortality sink for ectotherm colonizers.

    PubMed

    Maffucci, Fulvio; Corrado, Raffaele; Palatella, Luigi; Borra, Marco; Marullo, Salvatore; Hochscheid, Sandra; Lacorata, Guglielmo; Iudicone, Daniele

    2016-04-05

    Distribution shifts are a common adaptive response of marine ectotherms to climate change but the pace of redistribution depends on species-specific traits that may promote or hamper expansion to northern habitats. Here we show that recently, the loggerhead turtle (Caretta caretta) has begun to nest steadily beyond the northern edge of the species' range in the Mediterranean basin. This range expansion is associated with a significant warming of spring and summer sea surface temperature (SST) that offers a wider thermal window suitable for nesting. However, we found that post-hatchlings departing from this location experience low winter SST that may affect their survival and thus hamper the stabilization of the site by self-recruitment. The inspection of the Intergovernmental Panel on Climate Change model projections and observational data on SST trends shows that, despite the annual warming for this century, winter SST show little or no trends. Therefore, thermal constraints during the early developmental phase may limit the chance of population growth at this location also in the near future, despite increasingly favourable conditions at the nesting sites. Quantifying and understanding the interplay between dispersal and environmental changes at all life stages is critical for predicting ectotherm range expansion with climate warming.

  1. Seasonal heterogeneity of ocean warming: a mortality sink for ectotherm colonizers

    NASA Astrophysics Data System (ADS)

    Maffucci, Fulvio; Corrado, Raffaele; Palatella, Luigi; Borra, Marco; Marullo, Salvatore; Hochscheid, Sandra; Lacorata, Guglielmo; Iudicone, Daniele

    2016-04-01

    Distribution shifts are a common adaptive response of marine ectotherms to climate change but the pace of redistribution depends on species-specific traits that may promote or hamper expansion to northern habitats. Here we show that recently, the loggerhead turtle (Caretta caretta) has begun to nest steadily beyond the northern edge of the species’ range in the Mediterranean basin. This range expansion is associated with a significant warming of spring and summer sea surface temperature (SST) that offers a wider thermal window suitable for nesting. However, we found that post-hatchlings departing from this location experience low winter SST that may affect their survival and thus hamper the stabilization of the site by self-recruitment. The inspection of the Intergovernmental Panel on Climate Change model projections and observational data on SST trends shows that, despite the annual warming for this century, winter SST show little or no trends. Therefore, thermal constraints during the early developmental phase may limit the chance of population growth at this location also in the near future, despite increasingly favourable conditions at the nesting sites. Quantifying and understanding the interplay between dispersal and environmental changes at all life stages is critical for predicting ectotherm range expansion with climate warming.

  2. Holocene landscape response to seasonality of storms in the Mojave Desert

    USGS Publications Warehouse

    Miller, D.M.; Schmidt, K.M.; Mahan, S.A.; McGeehin, J.P.; Owen, L.A.; Barron, J.A.; Lehmkuhl, F.; Lohrer, R.

    2010-01-01

    New optically stimulated and radiocarbon ages for alluvial fan and lake deposits in the Mojave Desert are presented, which greatly improves the temporal resolution of surface processes. The new Mojave Desert climate-landscape record is particularly detailed for the late Holocene. Evidence from ephemeral lake deposits and landforms indicates times of sustained stream flow during a wet interval of the latter part of the Medieval Warm Period at ca. AD 1290 and during the Little Ice Age at ca. AD 1650. The former lakes postdate megadroughts of the Medieval Warm Period, whereas the latter match the Maunder Minimum of the Little Ice Age. Periods of alluvial fan aggradation across the Mojave Desert are 14-9 cal ka and 6-3 cal ka. This timing largely correlates to times of increased sea-surface temperatures in the Gulf of California and enhanced warm-season monsoons. This correlation suggests that sustained alluvial fan aggradation may be driven by intense summer-season storms. These data suggest that the close proximity of the Mojave Desert to the Pacific Ocean and the Gulf of California promotes a partitioning of landscape-process responses to climate forcings that vary with seasonality of the dominant storms. Cool-season Pacific frontal storms cause river flow, ephemeral lakes, and fan incision, whereas periods of intense warm-season storms cause hillslope erosion and alluvial fan aggradation. The proposed landscape-process partitioning has important implications for hazard mitigation given that climate change may increase sea-surface temperatures in the Gulf of California, which indirectly could increase future alluvial fan aggradation.

  3. Assessment of DNA damage in a group of professional dancers during a 10-month dancing season.

    PubMed

    Esteves, Filipa; Teixeira, Eduardo; Amorim, Tânia; Costa, Carla; Pereira, Cristiana; Fraga, Sónia; De Andrade, Vanessa Moraes; Teixeira, João Paulo; Costa, Solange

    2017-01-01

    Despite the numerous health benefits of physical activity, some studies reported that increased intensity and duration may induce oxidative stress in several cellular components including DNA. The aim of this study was to assess the level of basal DNA damage as well as oxidative DNA damage in a group of professional dancers before and after a 10-month dancing season. A group of individuals from general population was also assessed as a control. The alkaline version of the comet assay was the method selected to measure both basal DNA damage and oxidative stress, since this method quantifies both endpoints. In order to measure oxidative stress, the comet assay was coupled with a lesion-specific endonuclease (formamidopyrimidine glycosylase) to detect oxidized purines. The levels of oxidative DNA damage in dancers were significantly increased after the dancing season. Pre-season levels of oxidative DNA damage were lower in dancers than those obtained from the general population, suggesting an adaptation of antioxidant system in dancers. Results of the present biomonitoring study indicate the need for more effective measures to protect ballet dancers from potentially occupational health risks related to regular intensive physical exercise.

  4. Climate-induced seasonal changes in smallmouth bass growth rate potential at the southern range extent

    USGS Publications Warehouse

    Middaugh, Christopher R.; Kessinger, Brin; Magoulick, Daniel D.

    2018-01-01

    Temperature increases due to climate change over the coming century will likely affect smallmouth bass (Micropterus dolomieu) growth in lotic systems at the southern extent of their native range. However, the thermal response of a stream to warming climate conditions could be affected by the flow regime of each stream, mitigating the effects on smallmouth bass populations. We developed bioenergetics models to compare change in smallmouth bass growth rate potential (GRP) from present to future projected monthly stream temperatures across two flow regimes: runoff and groundwater-dominated. Seasonal differences in GRP between stream types were then compared. The models were developed for fourteen streams within the Ozark–Ouachita Interior Highlands in Arkansas, Oklahoma and Missouri, USA, which contain smallmouth bass. In our simulations, smallmouth bass mean GRP during summer months decreased by 0.005 g g−1 day−1 in runoff streams and 0.002 g g−1 day−1 in groundwater streams by the end of century. Mean GRP during winter, fall and early spring increased under future climate conditions within both stream types (e.g., 0.00019 g g−1 day−1 in runoff and 0.0014 g g−1 day−1 in groundwater streams in spring months). We found significant differences in change in GRP between runoff and groundwater streams in three seasons in end-of-century simulations (spring, summer and fall). Potential differences in stream temperature across flow regimes could be an important habitat component to consider when investigating effects of climate change as fishes from various flow regimes that are relatively close geographically could be affected differently by warming climate conditions.

  5. Spatio-temporal characteristics of global warming in the Tibetan Plateau during the last 50 years based on a generalised temperature zone-elevation model.

    PubMed

    Wei, Yanqiang; Fang, Yiping

    2013-01-01

    Temperature is one of the primary factors influencing the climate and ecosystem, and examining its change and fluctuation could elucidate the formation of novel climate patterns and trends. In this study, we constructed a generalised temperature zone elevation model (GTEM) to assess the trends of climate change and temporal-spatial differences in the Tibetan Plateau (TP) using the annual and monthly mean temperatures from 1961-2010 at 144 meteorological stations in and near the TP. The results showed the following: (1) The TP has undergone robust warming over the study period, and the warming rate was 0.318°C/decade. The warming has accelerated during recent decades, especially in the last 20 years, and the warming has been most significant in the winter months, followed by the spring, autumn and summer seasons. (2) Spatially, the zones that became significantly smaller were the temperature zones of -6°C and -4°C, and these have decreased 499.44 and 454.26 thousand sq km from 1961 to 2010 at average rates of 25.1% and 11.7%, respectively, over every 5-year interval. These quickly shrinking zones were located in the northwestern and central TP. (3) The elevation dependency of climate warming existed in the TP during 1961-2010, but this tendency has gradually been weakening due to more rapid warming at lower elevations than in the middle and upper elevations of the TP during 1991-2010. The higher regions and some low altitude valleys of the TP were the most significantly warming regions under the same categorizing criteria. Experimental evidence shows that the GTEM is an effective method to analyse climate changes in high altitude mountainous regions.

  6. Three decades of high-resolution coastal sea surface temperatures reveal more than warming.

    PubMed

    Lima, Fernando P; Wethey, David S

    2012-02-28

    Understanding and forecasting current and future consequences of coastal warming require a fine-scale assessment of the near-shore temperature changes. Here we show that despite the fact that 71% of the world's coastlines are significantly warming, rates of change have been highly heterogeneous both spatially and seasonally. We demonstrate that 46% of the coastlines have experienced a significant decrease in the frequency of extremely cold events, while extremely hot days are becoming more common in 38% of the area. Also, we show that the onset of the warm season is significantly advancing earlier in the year in 36% of the temperate coastal regions. More importantly, it is now possible to analyse local patterns within the global context, which is useful for a broad array of scientific fields, policy makers and general public.

  7. Climate variability and dengue fever in warm and humid Mexico.

    PubMed

    Colón-González, Felipe J; Lake, Iain R; Bentham, Graham

    2011-05-01

    Multiple linear regression models were fitted to look for associations between changes in the incidence rate of dengue fever and climate variability in the warm and humid region of Mexico. Data were collected for 12 Mexican provinces over a 23-year period (January 1985 to December 2007). Our results show that the incidence rate or risk of infection is higher during El Niño events and in the warm and wet season. We provide evidence to show that dengue fever incidence was positively associated with the strength of El Niño and the minimum temperature, especially during the cool and dry season. Our study complements the understanding of dengue fever dynamics in the region and may be useful for the development of early warning systems.

  8. The Tropical Western Hemisphere Warm Pool

    NASA Astrophysics Data System (ADS)

    Wang, C.; Enfield, D. B.

    2002-12-01

    The paper describes and examines variability of the tropical Western Hemisphere warm pool (WHWP) of water warmer than 28.5oC. The WHWP is the second-largest tropical warm pool on Earth. Unlike the Eastern Hemisphere warm pool in the western Pacific, which straddles the equator, the WHWP is entirely north of the equator. At various stages of development the WHWP extends over parts of the eastern North Pacific, the Gulf of Mexico, the Caribbean, and the western tropical North Atlantic. It has a large seasonal cycle and its interannual fluctuations of area and intensity are significant. Surface heat fluxes warm the WHWP through the boreal spring to an annual maximum of SST and WHWP area in the late summer/early fall, associated with eastern North Pacific and Atlantic hurricane activities and rainfall from northern South America to the southern tier of the United States. Observations suggest that a positive ocean-atmosphere feedback operating through longwave radiation and associated cloudiness seems to operate in the WHWP. During winter preceding large warm pool, there is an alteration of the Walker and Hadley circulation cells that serves as a "tropospheric bridge" for transferring Pacific ENSO effects to the Atlantic sector and inducing initial warming of warm pool. Associated with the warm SST anomalies is a decrease in sea level pressure anomalies and an anomalous increase in atmospheric convection and cloudiness. The increase in convective activity and cloudiness results in less net longwave radiation loss from the sea surface, which then reinforces SST anomalies.

  9. The response of aboveground plant productivity to earlier snowmelt and summer warming in an Arctic ecosystem

    NASA Astrophysics Data System (ADS)

    Livensperger, C.; Steltzer, H.; Darrouzet-Nardi, A.; Sullivan, P.; Wallenstein, M. D.; Weintraub, M. N.

    2012-12-01

    Plant communities in the Arctic are undergoing changes in structure and function due to shifts in seasonality from changing winters and summer warming. These changes will impact biogeochemical cycling, surface energy balance, and functioning of vertebrate and invertebrate communities. To examine seasonal controls on aboveground net primary production (ANPP) in a moist acidic tundra ecosystem in northern Alaska, we shifted the growing season by accelerating snowmelt (using radiation absorbing shadecloth) and warming air and soil temperature (using 1 m2 open-top chambers), individually and in combination. After three years, we measured ANPP by harvesting up to 16 individual ramets, tillers and rhizomes for each of 7 plant species, including two deciduous shrubs, two graminoids, two evergreen shrubs and one forb during peak season. Our results show that ANPP per stem summed across the 7 species increased when snow melt occurred earlier. However, standing biomass, excluding current year growth, was also greater. The ratio of ANPP/standing biomass decreased in all treatments compared to the control. ANPP per unit standing biomass summed for the four shrub species decreases due to summer warming alone or in combination with early snowmelt; however early snowmelt alone did not lead to lower ANPP for the shrubs. ANPP per tiller or rhizome summed for the three herbaceous species increased in response to summer warming. Understanding the differential response of plants to changing seasonality will inform predictions of future Arctic plant community structure and function.

  10. Variability of cold season surface air temperature over northeastern China and its linkage with large-scale atmospheric circulations

    NASA Astrophysics Data System (ADS)

    Zhuang, Yuanhuang; Zhang, Jingyong; Wang, Lin

    2018-05-01

    Cold temperature anomalies and extremes have profound effects on the society, the economy, and the environment of northeastern China (NEC). In this study, we define the cold season as the months from October to April, and investigate the variability of cold season surface air temperature (CSAT) over NEC and its relationships with large-scale atmospheric circulation patterns for the period 1981-2014. The empirical orthogonal function (EOF) analysis shows that the first EOF mode of the CSAT over NEC is characterized by a homogeneous structure that describes 92.2% of the total variance. The regionally averaged CSAT over NEC is closely linked with the Arctic Oscillation ( r = 0.62, 99% confidence level) and also has a statistically significant relation with the Polar/Eurasian pattern in the cold season. The positive phases of the Arctic Oscillation and the Polar/Eurasian pattern tend to result in a positive geopotential height anomaly over NEC and a weakened East Asian winter monsoon, which subsequently increase the CSAT over NEC by enhancing the downward solar radiation, strengthening the subsidence warming and warm air advection. Conversely, the negative phases of these two climate indices result in opposite regional atmospheric circulation anomalies and decrease the CSAT over NEC.

  11. Amazon Basin climate under global warming: the role of the sea surface temperature.

    PubMed

    Harris, Phil P; Huntingford, Chris; Cox, Peter M

    2008-05-27

    The Hadley Centre coupled climate-carbon cycle model (HadCM3LC) predicts loss of the Amazon rainforest in response to future anthropogenic greenhouse gas emissions. In this study, the atmospheric component of HadCM3LC is used to assess the role of simulated changes in mid-twenty-first century sea surface temperature (SST) in Amazon Basin climate change. When the full HadCM3LC SST anomalies (SSTAs) are used, the atmosphere model reproduces the Amazon Basin climate change exhibited by HadCM3LC, including much of the reduction in Amazon Basin rainfall. This rainfall change is shown to be the combined effect of SSTAs in both the tropical Atlantic and the Pacific, with roughly equal contributions from each basin. The greatest rainfall reduction occurs from May to October, outside of the mature South American monsoon (SAM) season. This dry season response is the combined effect of a more rapid warming of the tropical North Atlantic relative to the south, and warm SSTAs in the tropical east Pacific. Conversely, a weak enhancement of mature SAM season rainfall in response to Atlantic SST change is suppressed by the atmospheric response to Pacific SST. This net wet season response is sufficient to prevent dry season soil moisture deficits from being recharged through the SAM season, leading to a perennial soil moisture reduction and an associated 30% reduction in annual Amazon Basin net primary productivity (NPP). A further 23% NPP reduction occurs in response to a 3.5 degrees C warmer air temperature associated with a global mean SST warming.

  12. Seasonal Climate Profiles of an Ice-free Arctic Based on Intra-ring Analyses of δ18O Value in Fossil Wood

    NASA Astrophysics Data System (ADS)

    Schubert, B.; Jahren, A. H.

    2017-12-01

    Arctic sea ice thickness and extent are projected to continue their substantial decline during this century, with an 80% reduction in sea-ice extent by 2050. While there is a clear relationship between mean annual temperature (MAT) and the concentration of atmospheric carbon dioxide (pCO2) across both glacial and interglacial periods, data on seasonal fluctuations is limited. Here we report seasonal temperature estimates for the Arctic during the ice-free conditions of the late early to middle Eocene based upon exquisitely preserved, mummified wood collected from Banks Island, Northwest Territories, Canada ( 74 oN). Annual growth rings identified in the wood specimens were subdivided by hand at sub-millimeter resolution and cellulose was extracted from each sub-sample for determination of stable oxygen isotope (δ18O) value (n = 81). The data reveal a consistent, cyclic pattern of decreasing and increasing δ18O value up to 3‰ across growth rings that was consistent with patterns observed in other modern and fossil wood, including from other high latitude sites. From these data we quantified cold month and warm month seasonal temperatures using a previously published model (Schubert and Jahren, 2015, QSR, 125: 1-14). Our calculations revealed low overall seasonality in the Arctic during the Eocene with above-freezing winters and mild summers, consistent with the presence of high biomass temperate rainforests. These results highlight the importance of warm winters in maintaining ice-free conditions in the Arctic and suggest that increased winter temperatures in today's Arctic in response to rising pCO2 will be of particular importance for Arctic ice-loss.

  13. Warming and drought reduce temperature sensitivity of nitrogen transformations.

    PubMed

    Novem Auyeung, Dolaporn S; Suseela, Vidya; Dukes, Jeffrey S

    2013-02-01

    Shifts in nitrogen (N) mineralization and nitrification rates due to global changes can influence nutrient availability, which can affect terrestrial productivity and climate change feedbacks. While many single-factor studies have examined the effects of environmental changes on N mineralization and nitrification, few have examined these effects in a multifactor context or recorded how these effects vary seasonally. In an old-field ecosystem in Massachusetts, USA, we investigated the combined effects of four levels of warming (up to 4 °C) and three levels of precipitation (drought, ambient, and wet) on net N mineralization, net nitrification, and potential nitrification. We also examined the treatment effects on the temperature sensitivity of net N mineralization and net nitrification and on the ratio of C mineralization to net N mineralization. During winter, freeze-thaw events, snow depth, and soil freezing depth explained little of the variation in net nitrification and N mineralization rates among treatments. During two years of treatments, warming and altered precipitation rarely influenced the rates of N cycling, and there was no evidence of a seasonal pattern in the responses. In contrast, warming and drought dramatically decreased the apparent Q10 of net N mineralization and net nitrification, and the warming-induced decrease in apparent Q10 was more pronounced in ambient and wet treatments than the drought treatment. The ratio of C mineralization to net N mineralization varied over time and was sensitive to the interactive effects of warming and altered precipitation. Although many studies have found that warming tends to accelerate N cycling, our results suggest that warming can have little to no effect on N cycling in some ecosystems. Thus, ecosystem models that assume that warming will consistently increase N mineralization rates and inputs of plant-available N may overestimate the increase in terrestrial productivity and the magnitude of an important

  14. Monthly stumpage prices for the Pacific Northwest.

    Treesearch

    Richard W. Haynes

    1991-01-01

    Seasonal variation is found in monthly stumpage price data. Seasonal adjustments indicate that monthly adjustments improve the utility of estimates of monthly stumpage prices. Comparisons of adjusted and unadjusted prices suggest that the unadjusted price series are reasonably robust.

  15. Enhanced greenhouse gas emissions from the Arctic with experimental warming

    NASA Astrophysics Data System (ADS)

    Voigt, Carolina; Lamprecht, Richard E.; Marushchak, Maija E.; Lind, Saara E.; Novakovskiy, Alexander; Aurela, Mika; Martikainen, Pertti J.; Biasi, Christina

    2017-04-01

    Temperatures in the Arctic are projected to increase more rapidly than in lower latitudes. With temperature being a key factor for regulating biogeochemical processes in ecosystems, even a subtle temperature increase might promote the release of greenhouse gases (GHGs) to the atmosphere. Usually, carbon dioxide (CO2) and methane (CH4) are the GHGs dominating the climatic impact of tundra. However, bare, patterned ground features in the Arctic have recently been identified as hot spots for nitrous oxide (N2O). N2O is a potent greenhouse gas, which is almost 300 times more effective in its global warming potential than CO2; but studies on arctic N2O fluxes are rare. In this study we examined the impact of temperature increase on the seasonal GHG balance of all three important GHGs (CO2, CH4 and N2O) from three tundra surface types (vegetated peat soils, unvegetated peat soils, upland mineral soils) in the Russian Arctic (67˚ 03' N 62˚ 55' E), during the course of two growing seasons. We deployed open-top chambers (OTCs), inducing air and soil surface warming, thus mimicking predicted warming scenarios. We combined detailed CO2, CH4 and N2O flux studies with concentration measurements of these gases within the soil profile down to the active layer-permafrost interface, and complemented these GHG measurements with detailed soil nutrient (nitrate and ammonium) and dissolved organic carbon (DOC) measurements in the soil pore water profile. In our study, gentle air warming (˜1.0 ˚ C) increased the seasonal GHG release of all dominant surface types: the GHG budget of vegetated peat and mineral soils, which together cover more than 80 % of the land area in our study region, shifted from a sink to a source of -300 to 144 g CO2-eq m-2 and from -198 to 105 g CO2-eq m-2, respectively. While the positive warming response was governed by CO2, we provide here the first in situ evidence that warming increases arctic N2O emissions: Warming did not only enhance N2O emissions from

  16. Future warming and acidification effects on anti-fouling and anti-herbivory traits of the brown alga Fucus vesiculosus (Phaeophyceae).

    PubMed

    Raddatz, Stefanie; Guy-Haim, Tamar; Rilov, Gil; Wahl, Martin

    2017-02-01

    Human-induced ocean warming and acidification have received increasing attention over the past decade and are considered to have substantial consequences for a broad range of marine species and their interactions. Understanding how these interactions shift in response to climate change is particularly important with regard to foundation species, such as the brown alga Fucus vesiculosus. This macroalga represents the dominant habitat former on coastal rocky substrata of the Baltic Sea, fulfilling functions essential for the entire benthic community. Its ability to withstand extensive fouling and herbivory regulates the associated community and ecosystem dynamics. This study tested the interactive effects of future warming, acidification, and seasonality on the interactions of a marine macroalga with potential foulers and consumers. F. vesiculosus rockweeds were exposed to different combinations of conditions predicted regionally for the year 2100 (+∆5°C, +∆700 μatm CO 2 ) using multifactorial long-term experiments in novel outdoor benthic mesocosms ("Benthocosms") over 9-12-week periods in four seasons. Possible shifts in the macroalgal susceptibility to fouling and consumption were tested using consecutive bioassays. Algal susceptibility to fouling and grazing varied substantially among seasons and between treatments. In all seasons, warming predominantly affected anti-fouling and anti-herbivory interactions while acidification had a subtle nonsignificant influence. Interestingly, anti-microfouling activity was highest during winter under warming, while anti-macrofouling and anti-herbivory activities were highest in the summer under warming. These contrasting findings indicate that seasonal changes in anti-fouling and anti-herbivory traits may interact with ocean warming in altering F. vesiculosus community composition in the future. © 2016 Phycological Society of America.

  17. Climate and tourism in the Black Forest during the warm season.

    PubMed

    Endler, Christina; Matzarakis, Andreas

    2011-03-01

    Climate, climate change and tourism all interact. Part of the public discussion about climate change focusses on the tourism sector, with direct and indirect impacts being of equally high relevance. Climate and tourism are closely linked. Thus, climate is a very decisive factor in choices both of destination and of type of journey (active holidays, wellness, and city tours) in the tourism sector. However, whether choices about destinations or types of trip will alter with climate change is difficult to predict. Future climates can be simulated and projected, and the tendencies of climate parameters can be estimated using global and regional climate models. In this paper, the focus is on climate change in the mountainous regions of southwest Germany - the Black Forest. The Black Forest is one of the low mountain ranges where both winter and summer tourism are vulnerable to climate change due to its southern location; the strongest climatic changes are expected in areas covering the south and southwest of Germany. Moreover, as the choice of destination is highly dependent on good weather, a climatic assessment for tourism is essential. Thus, the aim of this study was to estimate climatic changes in mountainous regions during summer, especially for tourism and recreation. The assessment method was based on human-biometeorology as well as tourism-climatologic approaches. Regional climate simulations based on the regional climate model REMO were used for tourism-related climatic analyses. Emission scenarios A1B and B1 were considered for the time period 2021 to 2050, compared to the 30-year base period of 1971-2000, particularly for the warm period of the year, defined here as the months of March-November. In this study, we quantified the frequency, but not the means, of climate parameters. The study results show that global and regional warming is reflected in an increase in annual mean air temperature, especially in autumn. Changes in the spring show a slight negative

  18. Seasonal differences in thermal sensation in the outdoor urban environment of Mediterranean climates - the example of Athens, Greece

    NASA Astrophysics Data System (ADS)

    Tseliou, Areti; Tsiros, Ioannis X.; Nikolopoulou, Marialena

    2017-07-01

    Outdoor urban areas are very important for cities and microclimate is a critical parameter in the design process, contributing to thermal comfort which is important for urban developments. The research presented in this paper is part of extensive field surveys conducted in Athens aimed at investigating people's thermal sensation in a Mediterranean city. Based on 2313 questionnaires and microclimatic data the current work focuses on the relative frequencies of people's evaluation of the thermal along with the sun and wind sensations between two seasons trying to identify the seasonal differences in thermal sensation. The impact of basic meteorological factors on thermal discomfort with respect to season are also examined, as well as the use of the outdoor environment. Results show that psychological adaptation is an important contributing factor influencing perception of the thermal environment between seasons. In addition, the thermal sensation votes during the cool months show that individuals are satisfied to a great extend with the thermal environment whereas the combination of high air temperature, strong solar radiation and weak wind lead to thermal discomfort during summertime. As far as the appropriate urban design in the Mediterranean climate is concerned, priority should be given to the warm months of the year.

  19. Anthropogenic Warming Impacts on Today's Sierra Nevada Snowpack and Flood Severity

    NASA Astrophysics Data System (ADS)

    Huang, X.; Hall, A. D.; Berg, N.

    2017-12-01

    Focusing on this recent extreme wet year over California, this study investigates the warming impacts on the snowpack and the flood severity over the Sierra Nevada (SN), where the majority of the precipitation occurs during the winter season and early spring. One of our goals is to quantify anthropogenic warming impacts on the snow water equivalent (SWE) including recent historical warming and prescribed future projected warming scenarios; This work also explores to what extent flooding risk has increased under those warming cases. With a good representation of the historical precipitation and snowpack over the Sierra Nevada from the historical reference run at 9km (using WRF), the results from the offline Noah-MP simulations with perturbed near-surface temperatures reveal magnificent impacts of warming to the loss of the average snowpack. The reduction of the SWE under warming mainly results from the decreased rain-to-snow conversion with a weaker effect from increased snowmelt. Compared to the natural case, the past industrial warming decreased the maximum SWE by about one-fifth averaged over the study area. Future continuing warming can result in around one-third reduction of current maximum SWE under RCP4.5 emissions scenario, and the loss can reach to two-thirds under RCP8.5 as a "business-as-usual" condition. The impact of past warming is particularly outstanding over the North SN region where precipitation dominates and over the middle elevation regions where the snow mainly distributes. In the future, the warming impact on SWE progresses to higher regions, and so to the south and east. Under the business-as-usual scenario, the projected mid-elevation snowpack almost disappears by April 1st with even high-elevation snow reduced by about half. Along with the loss of the snowpack, as the temperature warms, floods can also intensify with increased early season runoff especially under heavy-rainy days caused by the weakened rain-to-snow processes and

  20. Convectively induced mesoscale weather systems in the tropical and warm-season midlatitude atmosphere

    NASA Astrophysics Data System (ADS)

    Smull, Bradley F.

    1995-07-01

    As anticipated by Nelson [1991] in the last U.S. National Report, mesoscale meteorology has continued to be an area of vigorous research activity. Progress is evinced by a growing number of process-oriented studies capitalizing on expanded observational capabilities, as well as more theoretical treatments employing numerical simulations of increasing sophistication. While the majority of papers within the scope of this review fall into the category of basic research, the field's maturation is evident in the emergence of a growing number of applications to operational weather forecasting. Even as our ability to anticipate shifts in synoptic scale upper-air patterns and associated baroclinic developments has steadily improved, lagging skill with regard to quantitative forecasts of precipitation—particularly in situations where deep moist convection is prevalent—has sustained research in warm-season mesoscale meteorology. Each spring and summer midlatitude populations are exposed to life-threatening natural weather phenomena in the form of lightning, tornadoes, straight-line winds, hail, and flash floods. This point was driven home during the summer of 1993, when an extraordinarily persistent series of mesoscale convective systems (MCSs) led to unusually severe and widespread flooding throughout the Mississippi and Missouri river basins. In addition to this obvious impact on regional climate, the 1990's have brought an increased appreciation for the less direct yet potentially significant role that tropical convection may play in shaping global climate through phenomena such as the El Niño-Southern Oscillation (ENSO).

  1. Effects of experimental warming and elevated CO2 on surface methane and CO­2 fluxes from a boreal black spruce peatland

    NASA Astrophysics Data System (ADS)

    Gill, A. L.; Finzi, A.; Giasson, M. A.

    2015-12-01

    High latitude peatlands represent a major terrestrial carbon store sensitive to climate change, as well as a globally significant methane source. While elevated atmospheric carbon dioxide concentrations and warming temperatures may increase peat respiration and C losses to the atmosphere, reductions in peatland water tables associated with increased growing season evapotranspiration may alter the nature of trace gas emission and increase peat C losses as CO2 relative to methane (CH4). As CH4 is a greenhouse gas with twenty times the warming potential of CO2, it is critical to understand how surface fluxes of CO2 and CH4 will be influenced by factors associated with global climate change. We used automated soil respiration chambers to assess the influence of elevated atmospheric CO2 and whole ecosystem warming on peatland CH4 and CO2 fluxes at the SPRUCE (Spruce and Peatland Responses Under Climatic and Environmental Change) Experiment in northern Minnesota. Belowground warming treatments were initiated in July 2014 and whole ecosystem warming and elevated CO2 treatments began in August 2015. Here we report soil iCO2 and iCH4 flux responses to the first year of belowground warming and the first two months of whole ecosystem manipulation. We also leverage the spatial and temporal density of measurements across the twenty autochambers to assess how physical (i.e., plant species composition, microtopography) and environmental (i.e., peat temperature, water table position, oxygen availability) factors influence observed rates of CH4 and CO2 loss. We find that methane fluxes increased significantly across warming treatments following the first year of belowground warming, while belowground warming alone had little influence on soil CO2 fluxes. Peat microtopography strongly influenced trace gas emission rates, with higher CH4 fluxes in hollow locations and higher CO2 fluxes in hummock locations. While there was no difference in the isotopic composition of the methane

  2. Environmental DNA (eDNA) Detection Probability Is Influenced by Seasonal Activity of Organisms.

    PubMed

    de Souza, Lesley S; Godwin, James C; Renshaw, Mark A; Larson, Eric

    2016-01-01

    Environmental DNA (eDNA) holds great promise for conservation applications like the monitoring of invasive or imperiled species, yet this emerging technique requires ongoing testing in order to determine the contexts over which it is effective. For example, little research to date has evaluated how seasonality of organism behavior or activity may influence detection probability of eDNA. We applied eDNA to survey for two highly imperiled species endemic to the upper Black Warrior River basin in Alabama, US: the Black Warrior Waterdog (Necturus alabamensis) and the Flattened Musk Turtle (Sternotherus depressus). Importantly, these species have contrasting patterns of seasonal activity, with N. alabamensis more active in the cool season (October-April) and S. depressus more active in the warm season (May-September). We surveyed sites historically occupied by these species across cool and warm seasons over two years with replicated eDNA water samples, which were analyzed in the laboratory using species-specific quantitative PCR (qPCR) assays. We then used occupancy estimation with detection probability modeling to evaluate both the effects of landscape attributes on organism presence and season of sampling on detection probability of eDNA. Importantly, we found that season strongly affected eDNA detection probability for both species, with N. alabamensis having higher eDNA detection probabilities during the cool season and S. depressus have higher eDNA detection probabilities during the warm season. These results illustrate the influence of organismal behavior or activity on eDNA detection in the environment and identify an important role for basic natural history in designing eDNA monitoring programs.

  3. The changing seasonal climate in the Arctic.

    PubMed

    Bintanja, R; van der Linden, E C

    2013-01-01

    Ongoing and projected greenhouse warming clearly manifests itself in the Arctic regions, which warm faster than any other part of the world. One of the key features of amplified Arctic warming concerns Arctic winter warming (AWW), which exceeds summer warming by at least a factor of 4. Here we use observation-driven reanalyses and state-of-the-art climate models in a variety of standardised climate change simulations to show that AWW is strongly linked to winter sea ice retreat through the associated release of surplus ocean heat gained in summer through the ice-albedo feedback (~25%), and to infrared radiation feedbacks (~75%). Arctic summer warming is surprisingly modest, even after summer sea ice has completely disappeared. Quantifying the seasonally varying changes in Arctic temperature and sea ice and the associated feedbacks helps to more accurately quantify the likelihood of Arctic's climate changes, and to assess their impact on local ecosystems and socio-economic activities.

  4. The changing seasonal climate in the Arctic

    PubMed Central

    Bintanja, R.; van der Linden, E. C.

    2013-01-01

    Ongoing and projected greenhouse warming clearly manifests itself in the Arctic regions, which warm faster than any other part of the world. One of the key features of amplified Arctic warming concerns Arctic winter warming (AWW), which exceeds summer warming by at least a factor of 4. Here we use observation-driven reanalyses and state-of-the-art climate models in a variety of standardised climate change simulations to show that AWW is strongly linked to winter sea ice retreat through the associated release of surplus ocean heat gained in summer through the ice-albedo feedback (~25%), and to infrared radiation feedbacks (~75%). Arctic summer warming is surprisingly modest, even after summer sea ice has completely disappeared. Quantifying the seasonally varying changes in Arctic temperature and sea ice and the associated feedbacks helps to more accurately quantify the likelihood of Arctic's climate changes, and to assess their impact on local ecosystems and socio-economic activities. PMID:23532038

  5. Spatial-temporal variations in the thermal growing degree-days and season under climate warming in China during 1960-2011

    NASA Astrophysics Data System (ADS)

    Yin, Yunhe; Deng, Haoyu; Wu, Shaohong

    2017-10-01

    Vegetation growth and phenology are largely regulated by base temperature (T b) and thermal accumulation. Hence, the growing degree-days (GDD) and growing season (GS) calculated based on T b have primary effects on terrestrial ecosystems, and could be changed by the significant warming during the last century. By choosing 0, 5, and 10 °C, three key T b for vegetation growth, the GDD and GS in China during 1960-2011 were developed based on 536 meteorological stations with homogenized daily mean temperatures. Results show that both the GDD and GS showed positive sensitivity to the annual mean temperature. The start of the growing season (SOS) has advanced by 4.86-6.71 days, and the end of the growing season (EOS) has been delayed by 4.32-6.19 days, lengthening the GS by 10.76-11.02 days in China as a whole during 1960-2011, depending on the T b chosen. Consistently, the GDD has totally increased 218.92-339.40 °C days during the 52 years, with trends more pronounced in those based on a lower T b. The GDD increase was significant (Mann-Kendall test, p < 0.01) over China except for the north of Southwest China, while the significant GS extension only scattered over China. Whereas the extensions of GS0 and GS5 were dominated by the advance in SOS, the GS10 extension was closely linked to the delay in EOS. Regionally, the GS extension in the eastern monsoon zone and northwest arid/semi-arid zone was driven by the advance in SOS and delay in EOS, respectively. Moreover, each variation has a substantial acceleration mostly in 1987 or 1996, and a speed reduction or even a trend reversal in the early 2000s. Changes in the thermal growing degree-days and season are expected to have great implications for biological phenology, agricultural production, and terrestrial carbon cycle in the future.

  6. Climate Variability and Dengue Fever in Warm and Humid Mexico

    PubMed Central

    Colón-González, Felipe J.; Lake, Iain R.; Bentham, Graham

    2011-01-01

    Multiple linear regression models were fitted to look for associations between changes in the incidence rate of dengue fever and climate variability in the warm and humid region of Mexico. Data were collected for 12 Mexican provinces over a 23-year period (January 1985 to December 2007). Our results show that the incidence rate or risk of infection is higher during El Niño events and in the warm and wet season. We provide evidence to show that dengue fever incidence was positively associated with the strength of El Niño and the minimum temperature, especially during the cool and dry season. Our study complements the understanding of dengue fever dynamics in the region and may be useful for the development of early warning systems. PMID:21540386

  7. From vegetation zones to climatypes: Effects of climate warming on Siberian ecosystems

    Treesearch

    N. M. Tchebakova; G. E. Rehfeldt; E. I. Parfenova

    2010-01-01

    Evidence for global warming over the past 200 years is overwhelming, based on both direct weather observation and indirect physical and biological indicators such as retreating glaciers and snow/ice cover, increasing sea level, and longer growing seasons (IPCC 2001, 2007). On the background of global warming at a rate of 0.6°C during the twentieth century (IPCC 2001),...

  8. Seasonal Variation in the Peritoneal Dialysis-Related Infections: A Single Center Experience in the Mediterranean.

    PubMed

    Buttigieg, Jesmar; Borg Cauchi, Angela; Rogers, Marilyn; Farrugia, Emanuel; Fava, Stephen

    2016-10-01

    Seasonal variation in the incidence of peritoneal dialysis-related infections (PDRI) has been sparingly investigated, especially in the Mediterranean. Our aim was to explore this association in Malta. All PDRI occurring between Jan-2008 and Dec-2012 were retrospectively studied.A total of 137 patients were followed-up for a median time of 32.5 months (range: 2-81). During this time, 19% never had PDRI, 11.7% transferred permanently to hemodialysis and 6.6% received a kidney transplant. A total of 279 PDRI were identified, equating to 145 catheter-related infections (CRI) and 144 peritonitis episodes (including 10 catheter related peritonitis). A spring peak in the overall gram positive PDRI (0.61 vs. 0.34/patient-year-at-risk, P=0.05), together with a peak in gram negative peritonitis in the warm period (0.13 vs. 0.07/patient-year at risk, P=0.04) was identified. The incidence rate ratios (Confidence Interval) involving the overall gram positive PDRI, gram positive peritonitis, coagulase-negative Streptococci (CoNS) and Streptococci were 1.82 (1.18-2.82, P=0.007), 2.20 (1.16-4.16, P=0.02), 2.65 (1.17-6.02, P=0.02] and 3.18 (1.03-9.98, P=0.04) in spring when compared to winter. No significant difference in the overall PDRI, peritonitis or CRI rates between seasons or warm/cold period was identified.To our knowledge, this is the first study which examines the effect of seasons on the incidence of PDRI in the Mediterranean basin. Findings suggest that spring confers a higher risk for gram positive PDRIs, gram positive peritonitis, CoNS and Streptococcus, whilst the warm period was associated with a peak in the gram negative peritonitis. © 2016 International Society for Apheresis, Japanese Society for Apheresis, and Japanese Society for Dialysis Therapy.

  9. Modelling the seasonality of Lyme disease risk and the potential impacts of a warming climate within the heterogeneous landscapes of Scotland

    PubMed Central

    Gilbert, Lucy; Harrison, Paula A.; Rounsevell, Mark D. A.

    2016-01-01

    Lyme disease is the most prevalent vector-borne disease in the temperate Northern Hemisphere. The abundance of infected nymphal ticks is commonly used as a Lyme disease risk indicator. Temperature can influence the dynamics of disease by shaping the activity and development of ticks and, hence, altering the contact pattern and pathogen transmission between ticks and their host animals. A mechanistic, agent-based model was developed to study the temperature-driven seasonality of Ixodes ricinus ticks and transmission of Borrelia burgdorferi sensu lato across mainland Scotland. Based on 12-year averaged temperature surfaces, our model predicted that Lyme disease risk currently peaks in autumn, approximately six weeks after the temperature peak. The risk was predicted to decrease with increasing altitude. Increases in temperature were predicted to prolong the duration of the tick questing season and expand the risk area to higher altitudinal and latitudinal regions. These predicted impacts on tick population ecology may be expected to lead to greater tick–host contacts under climate warming and, hence, greater risks of pathogen transmission. The model is useful in improving understanding of the spatial determinants and system mechanisms of Lyme disease pathogen transmission and its sensitivity to temperature changes. PMID:27030039

  10. Medieval Warm Period Archives Preserved in Limpet Shells (Patella Vulgata) From Viking Deposits, United Kingdom

    NASA Astrophysics Data System (ADS)

    Mobilia, M.; Surge, D.

    2008-12-01

    The Medieval Warm Period (700-1100 YBP) represents a recent period of warm climate, and as such provides a powerful comparison to today's continuing warming trend. However, the spatial and temporal variability inherent in the Medieval Warm Period (MWP) makes it difficult to differentiate between global climate trends and regional variability. The continued study of this period will allow for the better understanding of temperature variability, both regional and global, during this climate interval. Our study is located in the Orkney Islands, Scotland, which is a critical area to understand climate dynamics. The North Atlantic Oscillation and Gulf Stream heavily influence climate in this region, and the study of climate intervals during the MWP will improve our understanding of the behavior of these climate mechanisms during this interval. Furthermore, the vast majority of the climate archive has been derived from either deep marine or arctic environments. Studying a coastal environment will offer valuable insight into the behavior of maritime climate during the MWP. Estimated seasonal sea surface temperature data were derived through isotopic analysis of limpet shells (Patella vulgata). Analysis of modern shells confirms that growth temperature tracks seasonal variation in ambient water temperature. Preliminary data from MWP shells record a seasonal temperature range comparable to that observed in the modern temperature data. We will extend the range of temperature data from the 10th through 14th centuries to advance our knowledge of seasonal temperature variability during the late Holocene.

  11. Photoperiod constraints on tree phenology, performance and migration in a warming world.

    PubMed

    Way, Danielle A; Montgomery, Rebecca A

    2015-09-01

    Increasing temperatures should facilitate the poleward movement of species distributions through a variety of processes, including increasing the growing season length. However, in temperate and boreal latitudes, temperature is not the only cue used by trees to determine seasonality, as changes in photoperiod provide a more consistent, reliable annual signal of seasonality than temperature. Here, we discuss how day length may limit the ability of tree species to respond to climate warming in situ, focusing on the implications of photoperiodic sensing for extending the growing season and affecting plant phenology and growth, as well as the potential role of photoperiod in controlling carbon uptake and water fluxes in forests. We also review whether there are patterns across plant functional types (based on successional strategy, xylem anatomy and leaf morphology) in their sensitivity to photoperiod that we can use to predict which species or groups might be more successful in migrating as the climate warms, or may be more successfully used for forestry and agriculture through assisted migration schemes. © 2014 John Wiley & Sons Ltd.

  12. Variations in food and drink advertising in UK monthly women's magazines according to season, magazine type and socio-economic profile of readers: a descriptive study of publications over 12 months.

    PubMed

    Adams, Jean; Simpson, Emma; White, Martin

    2011-05-23

    Overweight and obesity are recognised nationally and internationally as key public health challenges. Food and drink advertising is one of the array of factors that influence both diet and physical activity choices and, hence, body weight and obesity. Little previous work has focused on food and drink advertising in magazines. We studied food and drink advertising in a wide range of popular UK monthly women's magazines published over a full year. We explored differences in the prevalence of food and drink advertising and the type of food and drinks advertised according to season, magazine type and socio-economic profile of readers. All advertisements in all issues of 18 popular UK monthly women's magazines published over 12 months were identified. For each food or drink advertisement, branded food and drinks were noted and categorised into one of seven food groups. All analyses were at the level of the individual advertisement. A total of 35 053 advertisements were identified; 1380 (3.9%) of these were for food or drink. The most common food group represented was 'food and drinks high in fat and/or sugar' (28.0% of food advertisements), the least common group was 'fruits & vegetables' (2.0% of food advertisements). Advertisements for alcohol accounted for 10.1% of all food advertisements. Food and drink advertisements were most common in summer, general interest magazines, and those with the most affluent readerships. There were some differences in the type of food and drink advertised across season, magazine type and socio-economic profile of readers. Food and drink advertisements represented only a small proportion of advertisements in UK women's monthly magazines. Food and drink advertisements in these magazines feature a high proportion of 'less healthy' foods. There were a number of differences across season, magazine type and according to the socio-economic profile of readers in the prevalence of food and drink advertisements. Fewer differences were seen in

  13. Variations in food and drink advertising in UK monthly women's magazines according to season, magazine type and socio-economic profile of readers: a descriptive study of publications over 12 months

    PubMed Central

    2011-01-01

    Background Overweight and obesity are recognised nationally and internationally as key public health challenges. Food and drink advertising is one of the array of factors that influence both diet and physical activity choices and, hence, body weight and obesity. Little previous work has focused on food and drink advertising in magazines. We studied food and drink advertising in a wide range of popular UK monthly women's magazines published over a full year. We explored differences in the prevalence of food and drink advertising and the type of food and drinks advertised according to season, magazine type and socio-economic profile of readers. Methods All advertisements in all issues of 18 popular UK monthly women's magazines published over 12 months were identified. For each food or drink advertisement, branded food and drinks were noted and categorised into one of seven food groups. All analyses were at the level of the individual advertisement. Results A total of 35 053 advertisements were identified; 1380 (3.9%) of these were for food or drink. The most common food group represented was 'food and drinks high in fat and/or sugar' (28.0% of food advertisements), the least common group was 'fruits & vegetables' (2.0% of food advertisements). Advertisements for alcohol accounted for 10.1% of all food advertisements. Food and drink advertisements were most common in summer, general interest magazines, and those with the most affluent readerships. There were some differences in the type of food and drink advertised across season, magazine type and socio-economic profile of readers. Conclusions Food and drink advertisements represented only a small proportion of advertisements in UK women's monthly magazines. Food and drink advertisements in these magazines feature a high proportion of 'less healthy' foods. There were a number of differences across season, magazine type and according to the socio-economic profile of readers in the prevalence of food and drink

  14. Seasonal and interannual variability of chlorophyll-a and associated physical synchronous variability in the western tropical Pacific

    NASA Astrophysics Data System (ADS)

    Hou, Xueyan; Dong, Qing; Xue, Cunjin; Wu, Shuchao

    2016-06-01

    Based on long-term satellite-derived ocean data sets and methods of empirical orthogonal function and singular value decomposition, we investigated the spatiotemporal variability of the chlorophyll-a concentration (CHL) on seasonal and interannual timescales in the western tropical Pacific associated with physical ocean variables of sea surface temperature (SST), sea level anomaly (SLA) and sea surface wind (SSW), and the El Niño Southern Oscillation (ENSO) index. The bio-physical synchronous variation on interannual timescale was also confirmed in terms of the scales of variability and oscillation periods in the time-frequency space using the methods of Fourier transform, Morlet wavelet transform, and wavelet coherence analysis. On a seasonal timescale, the first two modes of the monthly mean CHL fields described the consecutive spatiotemporal variation in CHL in the western tropical Pacific. CHL reached the maximum during late winter-early spring and minimum during summer-early autumn with the exception of the northeast of Papua New Guinea and the Solomon Islands. The CHL bloom in boreal winter-spring was closely associated with cold SST, high sea level along the North Equatorial Countercurrent meanders, and strong wind. On an interannual timescale, the variability of CHL exhibited a close correlation with SST, SLA, SSW, and ENSO. During El Niño, CHL increased in the oligotrophic western basin of the warm pool associated with cold SST, low SLA, and strong westerly winds but decreased in the mesotrophic eastern basin of the warm pool in association with warm SST, high SLA, and weak easterly trade winds. There may exist time-lag for the bio-physical covariation, i.e., CHL and SST varied simultaneously within 1 month, and CHL variations led SLA by approximately 0-3 months but lagged wind speed by about 1 month. In the time-frequency domain, the interannual variability in CHL and physical ocean variables had high common power, indicating that the variability scales

  15. Century-Long Warming Trends in the Upper Water Column of Lake Tanganyika.

    PubMed

    Kraemer, Benjamin M; Hook, Simon; Huttula, Timo; Kotilainen, Pekka; O'Reilly, Catherine M; Peltonen, Anu; Plisnier, Pierre-Denis; Sarvala, Jouko; Tamatamah, Rashid; Vadeboncoeur, Yvonne; Wehrli, Bernhard; McIntyre, Peter B

    2015-01-01

    Lake Tanganyika, the deepest and most voluminous lake in Africa, has warmed over the last century in response to climate change. Separate analyses of surface warming rates estimated from in situ instruments, satellites, and a paleolimnological temperature proxy (TEX86) disagree, leaving uncertainty about the thermal sensitivity of Lake Tanganyika to climate change. Here, we use a comprehensive database of in situ temperature data from the top 100 meters of the water column that span the lake's seasonal range and lateral extent to demonstrate that long-term temperature trends in Lake Tanganyika depend strongly on depth, season, and latitude. The observed spatiotemporal variation in surface warming rates accounts for small differences between warming rate estimates from in situ instruments and satellite data. However, after accounting for spatiotemporal variation in temperature and warming rates, the TEX86 paleolimnological proxy yields lower surface temperatures (1.46 °C lower on average) and faster warming rates (by a factor of three) than in situ measurements. Based on the ecology of Thaumarchaeota (the microbes whose biomolecules are involved with generating the TEX86 proxy), we offer a reinterpretation of the TEX86 data from Lake Tanganyika as the temperature of the low-oxygen zone, rather than of the lake surface temperature as has been suggested previously. Our analyses provide a thorough accounting of spatiotemporal variation in warming rates, offering strong evidence that thermal and ecological shifts observed in this massive tropical lake over the last century are robust and in step with global climate change.

  16. Century-Long Warming Trends in the Upper Water Column of Lake Tanganyika

    PubMed Central

    Kraemer, Benjamin M.; Hook, Simon; Huttula, Timo; Kotilainen, Pekka; O’Reilly, Catherine M.; Peltonen, Anu; Plisnier, Pierre-Denis; Sarvala, Jouko; Tamatamah, Rashid; Vadeboncoeur, Yvonne; Wehrli, Bernhard; McIntyre, Peter B.

    2015-01-01

    Lake Tanganyika, the deepest and most voluminous lake in Africa, has warmed over the last century in response to climate change. Separate analyses of surface warming rates estimated from in situ instruments, satellites, and a paleolimnological temperature proxy (TEX86) disagree, leaving uncertainty about the thermal sensitivity of Lake Tanganyika to climate change. Here, we use a comprehensive database of in situ temperature data from the top 100 meters of the water column that span the lake’s seasonal range and lateral extent to demonstrate that long-term temperature trends in Lake Tanganyika depend strongly on depth, season, and latitude. The observed spatiotemporal variation in surface warming rates accounts for small differences between warming rate estimates from in situ instruments and satellite data. However, after accounting for spatiotemporal variation in temperature and warming rates, the TEX86 paleolimnological proxy yields lower surface temperatures (1.46 °C lower on average) and faster warming rates (by a factor of three) than in situ measurements. Based on the ecology of Thaumarchaeota (the microbes whose biomolecules are involved with generating the TEX86 proxy), we offer a reinterpretation of the TEX86 data from Lake Tanganyika as the temperature of the low-oxygen zone, rather than of the lake surface temperature as has been suggested previously. Our analyses provide a thorough accounting of spatiotemporal variation in warming rates, offering strong evidence that thermal and ecological shifts observed in this massive tropical lake over the last century are robust and in step with global climate change. PMID:26147964

  17. Seasonal Variations in Color Preference.

    PubMed

    Schloss, Karen B; Nelson, Rolf; Parker, Laura; Heck, Isobel A; Palmer, Stephen E

    2017-08-01

    We investigated how color preferences vary according to season and whether those changes could be explained by the ecological valence theory (EVT). To do so, we assessed the same participants' preferences for the same colors during fall, winter, spring, and summer in the northeastern United States, where there are large seasonal changes in environmental colors. Seasonal differences were most pronounced between fall and the other three seasons. Participants liked fall-associated dark-warm colors-for example, dark-red, dark-orange (brown), dark-yellow (olive), and dark-chartreuse-more during fall than other seasons. The EVT could explain these changes with a modified version of Palmer and Schloss' (2010) weighted affective valence estimate (WAVE) procedure that added an activation term to the WAVE equation. The results indicate that color preferences change according to season, as color-associated objects become more/less activated in the observer. These seasonal changes in color preferences could not be characterized by overall shifts in weights along cone-contrast axes. Copyright © 2016 Cognitive Science Society, Inc.

  18. Birth seasonality and offspring production in threatened neotropical primates related to climate

    USGS Publications Warehouse

    Wiederholt, R.; Post, E.

    2011-01-01

    Given the threatened status of many primate species, the impacts of global warming on primate reproduction and, consequently, population growth should be of concern. We examined relations between climatic variability and birth seasonality, offspring production, and infant sex ratios in two ateline primates, northern muriquis, and woolly monkeys. In both species, the annual birth season was delayed by dry conditions and El Ni??o years, and delayed birth seasons were linked to lower birth rates. Additionally, increased mean annual temperatures were associated with lower birth rates for northern muriquis. Offspring sex ratios varied with climatic conditions in both species, but in different ways: directly in woolly monkeys and indirectly in northern muriquis. Woolly monkeys displayed an increase in the proportion of males among offspring in association with El Ni??o events, whereas in northern muriquis, increases in the proportion of males among offspring were associated with delayed onset of the birth season, which itself was related, although weakly, to warm, dry conditions. These results illustrate that global warming, increased drought frequency, and changes in the frequency of El Ni??o events could limit primate reproductive output, threatening the persistence and recovery of ateline primate populations. ?? 2011 Blackwell Publishing Ltd.

  19. Spatio-Temporal Characteristics of Global Warming in the Tibetan Plateau during the Last 50 Years Based on a Generalised Temperature Zone - Elevation Model

    PubMed Central

    Wei, Yanqiang; Fang, Yiping

    2013-01-01

    Temperature is one of the primary factors influencing the climate and ecosystem, and examining its change and fluctuation could elucidate the formation of novel climate patterns and trends. In this study, we constructed a generalised temperature zone elevation model (GTEM) to assess the trends of climate change and temporal-spatial differences in the Tibetan Plateau (TP) using the annual and monthly mean temperatures from 1961–2010 at 144 meteorological stations in and near the TP. The results showed the following: (1) The TP has undergone robust warming over the study period, and the warming rate was 0.318°C/decade. The warming has accelerated during recent decades, especially in the last 20 years, and the warming has been most significant in the winter months, followed by the spring, autumn and summer seasons. (2) Spatially, the zones that became significantly smaller were the temperature zones of −6°C and −4°C, and these have decreased 499.44 and 454.26 thousand sq km from 1961 to 2010 at average rates of 25.1% and 11.7%, respectively, over every 5-year interval. These quickly shrinking zones were located in the northwestern and central TP. (3) The elevation dependency of climate warming existed in the TP during 1961–2010, but this tendency has gradually been weakening due to more rapid warming at lower elevations than in the middle and upper elevations of the TP during 1991–2010. The higher regions and some low altitude valleys of the TP were the most significantly warming regions under the same categorizing criteria. Experimental evidence shows that the GTEM is an effective method to analyse climate changes in high altitude mountainous regions. PMID:23565182

  20. Nitrous Oxide Emissions from Riparian Forest Buffers, Warm-Season and Cool-Season Grass Filters, and Crop Fields

    USDA-ARS?s Scientific Manuscript database

    Increasing denitrification rates in riparian buffers may be trading the problem of nonpoint source (NPS) pollution of surface waters for atmospheric deterioration and increased global warming potential because denitrification produces nitrous oxide (N2O), a greenhouse gas also involved in stratosphe...

  1. 0-6613 : evaluate binder and mixture aging for warm mix asphalt.

    DOT National Transportation Integrated Search

    2013-08-01

    Warm mix asphalt (WMA) technologies employ reduced : mixing and placement temperatures, thereby allowing : reduced fuel consumption, enhanced compaction, : increased haul distances, and an extended paving : season. However, there have been issues of ...

  2. Scaling Potential Evapotranspiration with Greenhouse Warming (Invited)

    NASA Astrophysics Data System (ADS)

    Scheff, J.; Frierson, D. M.

    2013-12-01

    Potential evapotranspiration (PET) is a supply-independent measure of the evaporative demand of a terrestrial climate, of basic importance in climatology, hydrology, and agriculture. Future increases in PET from greenhouse warming are often cited as key drivers of global trends toward drought and aridity. The present work computes recent and business-as-usual-future Penman-Monteith (i.e. physically-based) PET fields at 3-hourly resolution in 14 modern global climate models. The %-change in local annual-mean PET over the upcoming century is almost always positive, modally low double-digit in magnitude, usually increasing with latitude, yet quite divergent between models. These patterns are understood as follows. In every model, the global field of PET %-change is found to be dominated by the direct, positive effects of constant-relative-humidity warming (via increasing vapor pressure deficit and increasing Clausius-Clapeyron slope.) This direct-warming term very accurately scales as the PET-weighted (warm-season daytime) local warming, times 5-6% per degree (related to the Clausius-Clapeyron equation), times an analytic factor ranging from about 0.25 in warm climates to 0.75 in cold climates, plus a small correction. With warming of several degrees, this product is of low double-digit magnitude, and the strong temperature dependence gives the latitude dependence. Similarly, the inter-model spread in the amount of warming gives most of the spread in this term. Additional spread in the total change comes from strong disagreement on radiation, relative-humidity, and windspeed changes, which make smaller yet substantial contributions to the full PET %-change fields.

  3. Linkage Between Hourly Precipitation Events and Atmospheric Temperature Changes over China during the Warm Season

    PubMed Central

    Miao, Chiyuan; Sun, Qiaohong; Borthwick, Alistair G. L.; Duan, Qingyun

    2016-01-01

    We investigated changes in the temporospatial features of hourly precipitation during the warm season over mainland China. The frequency and amount of hourly precipitation displayed latitudinal zonation, especially for light and moderate precipitation, which showed successive downward change over time in northeastern and southern China. Changes in the precipitation amount resulted mainly from changes in frequency rather than changes in intensity. We also evaluated the linkage between hourly precipitation and temperature variations and found that hourly precipitation extreme was more sensitive to temperature than other categories of precipitation. A strong dependency of hourly precipitation on temperature occurred at temperatures colder than the median daily temperature; in such cases, regression slopes were greater than the Clausius-Clapeyron (C-C) relation of 7% per degree Celsius. Regression slopes for 31.6%, 59.8%, 96.9%, and 99.1% of all stations were greater than 7% per degree Celsius for the 75th, 90th, 99th, and 99.9th percentiles for precipitation, respectively. The mean regression slopes within the 99.9th percentile of precipitation were three times the C-C rate. Hourly precipitation showed a strong negative relationship with daily maximum temperature and the diurnal temperature range at most stations, whereas the equivalent correlation for daily minimum temperature was weak. PMID:26931350

  4. Environmental DNA (eDNA) Detection Probability Is Influenced by Seasonal Activity of Organisms

    PubMed Central

    de Souza, Lesley S.; Godwin, James C.; Renshaw, Mark A.; Larson, Eric

    2016-01-01

    Environmental DNA (eDNA) holds great promise for conservation applications like the monitoring of invasive or imperiled species, yet this emerging technique requires ongoing testing in order to determine the contexts over which it is effective. For example, little research to date has evaluated how seasonality of organism behavior or activity may influence detection probability of eDNA. We applied eDNA to survey for two highly imperiled species endemic to the upper Black Warrior River basin in Alabama, US: the Black Warrior Waterdog (Necturus alabamensis) and the Flattened Musk Turtle (Sternotherus depressus). Importantly, these species have contrasting patterns of seasonal activity, with N. alabamensis more active in the cool season (October-April) and S. depressus more active in the warm season (May-September). We surveyed sites historically occupied by these species across cool and warm seasons over two years with replicated eDNA water samples, which were analyzed in the laboratory using species-specific quantitative PCR (qPCR) assays. We then used occupancy estimation with detection probability modeling to evaluate both the effects of landscape attributes on organism presence and season of sampling on detection probability of eDNA. Importantly, we found that season strongly affected eDNA detection probability for both species, with N. alabamensis having higher eDNA detection probabilities during the cool season and S. depressus have higher eDNA detection probabilities during the warm season. These results illustrate the influence of organismal behavior or activity on eDNA detection in the environment and identify an important role for basic natural history in designing eDNA monitoring programs. PMID:27776150

  5. [Effects of diurnal warming on soil N2O emission in soybean field].

    PubMed

    Hu, Zheng-Hua; Zhou, Ying-Ping; Cui, Hai-Ling; Chen, Shu-Tao; Xiao, Qi-Tao; Liu, Yan

    2013-08-01

    To investigate the impact of experimental warming on N2O emission from soil of soybean field, outdoor experiments with simulating diurnal warming were conducted, and static dark chamber-gas chromatograph method was used to measure N2O emission fluxes. Results indicated that: the diurnal warming did not change the seasonal pattern of N2O emissions from soil. In the whole growing season, comparing to the control treatment (CK), the warming treatment (T) significantly enhanced the N2O flux and the cumulative amount of N2O by 17.31% (P = 0.019), and 20.27% (P = 0.005), respectively. The significant correlations were found between soil N2O emission and soil temperature, moisture. The temperature sensitivity values of soil N2O emission under CK and T treatments were 3.75 and 4.10, respectively. In whole growing stage, T treatment significantly increased the crop aboveground and total biomass, the nitrate reductase activity, and total nitrogen in leaves, while significantly decreased NO3(-) -N content in leaves. T treatment significantly increased soil NO3(-) -N content, but had no significant effect on soil organic carbon and total nitrogen contents. The results of this study suggested that diurnal warming enhanced N2O emission from soil in soybean field.

  6. Response of ocean ecosystems to climate warming

    NASA Astrophysics Data System (ADS)

    Sarmiento, J. L.; Slater, R.; Barber, R.; Bopp, L.; Doney, S. C.; Hirst, A. C.; Kleypas, J.; Matear, R.; Mikolajewicz, U.; Monfray, P.; Soldatov, V.; Spall, S. A.; Stouffer, R.

    2004-09-01

    We examine six different coupled climate model simulations to determine the ocean biological response to climate warming between the beginning of the industrial revolution and 2050. We use vertical velocity, maximum winter mixed layer depth, and sea ice cover to define six biomes. Climate warming leads to a contraction of the highly productive marginal sea ice biome by 42% in the Northern Hemisphere and 17% in the Southern Hemisphere, and leads to an expansion of the low productivity permanently stratified subtropical gyre biome by 4.0% in the Northern Hemisphere and 9.4% in the Southern Hemisphere. In between these, the subpolar gyre biome expands by 16% in the Northern Hemisphere and 7% in the Southern Hemisphere, and the seasonally stratified subtropical gyre contracts by 11% in both hemispheres. The low-latitude (mostly coastal) upwelling biome area changes only modestly. Vertical stratification increases, which would be expected to decrease nutrient supply everywhere, but increase the growing season length in high latitudes. We use satellite ocean color and climatological observations to develop an empirical model for predicting chlorophyll from the physical properties of the global warming simulations. Four features stand out in the response to global warming: (1) a drop in chlorophyll in the North Pacific due primarily to retreat of the marginal sea ice biome, (2) a tendency toward an increase in chlorophyll in the North Atlantic due to a complex combination of factors, (3) an increase in chlorophyll in the Southern Ocean due primarily to the retreat of and changes at the northern boundary of the marginal sea ice zone, and (4) a tendency toward a decrease in chlorophyll adjacent to the Antarctic continent due primarily to freshening within the marginal sea ice zone. We use three different primary production algorithms to estimate the response of primary production to climate warming based on our estimated chlorophyll concentrations. The three algorithms give

  7. Reconstructing seasonal climate from high-resolution carbon and oxygen isotope measurements across tree rings

    NASA Astrophysics Data System (ADS)

    Schubert, B.; Jahren, H.

    2014-12-01

    Intra-annual records of carbon (δ13C) and oxygen (δ18O) isotope measurements across tree rings reveal significant changes in δ13C and δ18O value across each growing season. We previously found that across a broad range of climate regimes, the seasonal change in δ13C measured within tree rings reflects changes in seasonal precipitation amount, and demonstrated its utility for quantifying seasonal paleo-precipitation from non-permineralized, fossil wood. Here we produce an equation relating intra-ring changes in δ18O to seasonal changes in temperature and precipitation amount, but the equation yields for unknowns (summer and winter precipitation amounts, and cold and warm month mean temperatures). By combining high-resolution δ13C and δ18O records with independent estimates of mean annual temperature and mean annual precipitation, we show how our general, global relationships could be used to quantify seasonal climate information from fossil sites. We validate our approach using high-resolution δ13C and δ18O data from trees growing at five modern sites (Hawaii, Alaska, Norway, Guyana, and Kenya). The reconstructed estimates of seasonal precipitation and temperature showed excellent agreement with the known climate data for each site (precipitation: R2 = 0.98; temperature: R2 = 0.91). These results confirm that across diverse sites and tree species, seasonal climate information can be accurately quantified using a combination of carbon and oxygen intra-ring isotope profiles.

  8. Cold season emissions dominate the Arctic tundra methane budget

    NASA Astrophysics Data System (ADS)

    Zona, Donatella; Gioli, Beniamino; Commane, Róisín; Lindaas, Jakob; Wofsy, Steven C.; Miller, Charles E.; Dinardo, Steven J.; Dengel, Sigrid; Sweeney, Colm; Karion, Anna; Chang, Rachel Y.-W.; Henderson, John M.; Murphy, Patrick C.; Goodrich, Jordan P.; Moreaux, Virginie; Liljedahl, Anna; Watts, Jennifer D.; Kimball, John S.; Lipson, David A.; Oechel, Walter C.

    2016-01-01

    Arctic terrestrial ecosystems are major global sources of methane (CH4); hence, it is important to understand the seasonal and climatic controls on CH4 emissions from these systems. Here, we report year-round CH4 emissions from Alaskan Arctic tundra eddy flux sites and regional fluxes derived from aircraft data. We find that emissions during the cold season (September to May) account for ≥50% of the annual CH4 flux, with the highest emissions from noninundated upland tundra. A major fraction of cold season emissions occur during the "zero curtain" period, when subsurface soil temperatures are poised near 0 °C. The zero curtain may persist longer than the growing season, and CH4 emissions are enhanced when the duration is extended by a deep thawed layer as can occur with thick snow cover. Regional scale fluxes of CH4 derived from aircraft data demonstrate the large spatial extent of late season CH4 emissions. Scaled to the circumpolar Arctic, cold season fluxes from tundra total 12 ± 5 (95% confidence interval) Tg CH4 y-1, ∼25% of global emissions from extratropical wetlands, or ∼6% of total global wetland methane emissions. The dominance of late-season emissions, sensitivity to soil environmental conditions, and importance of dry tundra are not currently simulated in most global climate models. Because Arctic warming disproportionally impacts the cold season, our results suggest that higher cold-season CH4 emissions will result from observed and predicted increases in snow thickness, active layer depth, and soil temperature, representing important positive feedbacks on climate warming.

  9. Cold season emissions dominate the Arctic tundra methane budget.

    PubMed

    Zona, Donatella; Gioli, Beniamino; Commane, Róisín; Lindaas, Jakob; Wofsy, Steven C; Miller, Charles E; Dinardo, Steven J; Dengel, Sigrid; Sweeney, Colm; Karion, Anna; Chang, Rachel Y-W; Henderson, John M; Murphy, Patrick C; Goodrich, Jordan P; Moreaux, Virginie; Liljedahl, Anna; Watts, Jennifer D; Kimball, John S; Lipson, David A; Oechel, Walter C

    2016-01-05

    Arctic terrestrial ecosystems are major global sources of methane (CH4); hence, it is important to understand the seasonal and climatic controls on CH4 emissions from these systems. Here, we report year-round CH4 emissions from Alaskan Arctic tundra eddy flux sites and regional fluxes derived from aircraft data. We find that emissions during the cold season (September to May) account for ≥ 50% of the annual CH4 flux, with the highest emissions from noninundated upland tundra. A major fraction of cold season emissions occur during the "zero curtain" period, when subsurface soil temperatures are poised near 0 °C. The zero curtain may persist longer than the growing season, and CH4 emissions are enhanced when the duration is extended by a deep thawed layer as can occur with thick snow cover. Regional scale fluxes of CH4 derived from aircraft data demonstrate the large spatial extent of late season CH4 emissions. Scaled to the circumpolar Arctic, cold season fluxes from tundra total 12 ± 5 (95% confidence interval) Tg CH4 y(-1), ∼ 25% of global emissions from extratropical wetlands, or ∼ 6% of total global wetland methane emissions. The dominance of late-season emissions, sensitivity to soil environmental conditions, and importance of dry tundra are not currently simulated in most global climate models. Because Arctic warming disproportionally impacts the cold season, our results suggest that higher cold-season CH4 emissions will result from observed and predicted increases in snow thickness, active layer depth, and soil temperature, representing important positive feedbacks on climate warming.

  10. Response of changes in seasonal soil freeze/thaw state to climate change from 1950 to 2010 across china

    NASA Astrophysics Data System (ADS)

    Peng, Xiaoqing; Frauenfeld, Oliver W.; Cao, Bin; Wang, Kang; Wang, Huijuan; Su, Hang; Huang, Zhe; Yue, Dongxia; Zhang, Tingjun

    2016-11-01

    Variations in seasonal soil freeze/thaw state are important indicators of climate change and influence ground temperature, hydrological processes, surface energy, and the moisture balance. Previous studies mainly focused on the active layer and permafrost, while seasonally frozen ground research in nonpermafrost regions has received less attention. In this study, we investigate the response of changes in seasonal soil freeze/thaw state to changes in air temperatures by combining observations from more than 800 stations with gridded mean monthly air temperature data across China. The results show that mean annual air temperature (MAAT) increased statistically significantly by 0.29 ± 0.03°C/decade from 1967 to 2013, with greater warming on the Qinghai-Tibetan Plateau. There is a statistically significant decrease in the freeze/thaw cycle (FTC) at 0.39 ± 0.05 cycles/decade. In addition, there are strong negative correlations between FTC and MAAT. Estimating the soil freeze/thaw state classification based on the number of days in the month, we find that changes of mean annual area extent of seasonal soil freeze/thaw state decreased significantly for completely frozen (CF) ground, while the area extent of partially frozen (PF) and unfrozen (UF) ground both increased. Changes in mean monthly area extent of seasonal soil freeze/thaw state indicate that the extent of CF and UF area was decreasing and increasing, respectively. But for the extent of PF areas, both increasing and decreasing trends were observed. Quantifying the spatial pattern of the seasonal soil freeze/thaw, we find that CF and PF areas are located in northern China and the Tibetan Plateau from December to March, and UF areas are located in southern China. The variations of mean annual area extent departure of soil freeze/thaw states are consistent with MAAT changes in different land cover types across China.

  11. Seasonality and growth patterns using isotope sclerochronology in shells of the Pliocene scallop Chesapecten madisonius

    NASA Astrophysics Data System (ADS)

    Goewert, Ann E.; Surge, Donna

    2008-10-01

    Growth lines and variation in oxygen and carbon isotope ratios (δ18O and δ13C) in shells of the Pliocene scallop Chesapecten madisonius preserve seasonal chronologies of biological and environmental change. This study evaluated whether (1) prominent growth lines were formed annually, and (2) growth rates estimated using isotope sclerochronology were comparable to rates estimated using visual inspection (measuring the width between external growth lines). We compared both techniques for estimating growth rates and age on three late to mid-Pliocene C. madisonius shells. The first approach located prominent growth lines on the δ18O time series, and differentiated between annual and non-annual (disturbance) growth lines. The second approach assumed all prominent lines were annual. This comparison showed that visual inspection underestimated growth rates and overestimated age. Seasonal timing of annual growth line formation using isotope sclerochronology provided unexpected results. Because this region fell within the warm-temperate paleobiogeographic province, we predicted annual lines formed during summers (most negative δ18O values). Instead, annual growth lines coincided with the most positive δ18O values (winter), typical of bivalves from cold-temperate regions. Moreover, shells recorded seasonal temperatures ranging from 3.2-20.8°C, a range lower than the thermal regime defined for warm-temperate environments (8-25°C). Possibly, the Sea Slope Gyre, which mixed eddies and cold filaments of the Labrador Current and warm waters of the Gulf Stream, penetrated the warm-temperate environment in this region. Alternatively, warm-water fauna from the zoogeographic Carolinian subprovince migrated northward and endured by virtue of warm summer temperatures. Regardless of the explanation, our findings provide a glimpse of mid-latitude seasonal temperature range for a warm climate episode during the mid-Pliocene.

  12. Effects of air pollution and seasons on health-related quality of life of Mongolian adults living in Ulaanbaatar: cross-sectional studies.

    PubMed

    Nakao, Motoyuki; Yamauchi, Keiko; Ishihara, Yoko; Omori, Hisamitsu; Ichinnorov, Dashtseren; Solongo, Bandi

    2017-06-23

    Ulaanbaatar, Mongolia, is known as severely air-polluted city in the world due to increased coal consumption in the cold season. The health effects of air pollution in Mongolia such as mortality, morbidity and symptoms have been previously reported. However, the concept of health-related quality of life (HR-QoL), which refers to the individual's perception of well-being, should also be included as an adverse health outcome of air pollution. Surveys on the Mongolian people living in Ulaanbaatar were performed in the warm and cold seasons. Self-completed questionnaires on the subjects' HR-QoL, data from health checkups and pulmonary function tests by respiratory specialists were collected for Mongolian adults aged 40-79 years (n = 666). Ambient PM2.5 and PM10 were concurrently sampled and the components were analyzed to estimate the source of air pollution. In logistic regression analyses, respiratory symptoms and smoke-rich fuels were associated with reduced HR-QoL (> 50th percentile vs. ≤ 50th percentile). PM 2.5 levels were much higher in the cold season (median 86.4 μg/m 3 (IQR: 58.7-121.0)) than in the warm season (12.2 μg/m 3 (8.9-21.2). The receptor model revealed that the high PM2.5 concentration in the cold season could be attributed to solid fuel combustion. The difference in HR-QoL between subjects with and without ventilatory impairment was assessed after the stratification of the subjects by season and household fuel type. There were no significant differences in HR-QoL between subjects with and without ventilatory impairment regardless of household fuel type in the warm season. In contrast, subjects with ventilatory impairment who used smoke-rich fuel in the cold season had a significantly lower HR-QoL. Our study showed that air pollution in Ulaanbaatar worsened in the cold season and was estimated to be contributed by solid fuel combustion. Various aspects of HR-QoL in subjects with ventilatory impairment using smoke-rich fuels deteriorated

  13. Seasonal soil moisture patterns in contrasting habitats in the Willamette Valley, Oregon

    EPA Science Inventory

    Changing seasonal soil moisture regimes caused by global warming may alter plant community composition in sensitive habitats such as wetlands and oak savannas. To evaluate such changes, an understanding of typical seasonal soil moisture regimes is necessary. The primary objective...

  14. Monthly and seasonal variations of aerosol optical properties and direct radiative forcing over Zanjan, Iran

    NASA Astrophysics Data System (ADS)

    Gharibzadeh, Maryam; Alam, Khan; Abedini, Yousefali; Bidokhti, Abbasali Aliakbari; Masoumi, Amir

    2017-11-01

    Aerosol optical properties and radiative forcing over Zanjan in northwest of Iran has been analyzed during 2010-2013. The aerosol optical and radiative properties are less studied over Zanjan, and therefore, require a careful and in depth analysis. The optical properties like Aerosol Optical Depth (AOD), Ångström Exponent (AE), ASYmmetry parameter (ASY), Single Scattering Albedo (SSA), and Aerosol Volume Size Distribution (AVSD) have been evaluated using the ground-based AErosol RObotic NETwork (AERONET) data. Higher AOD while relatively lower AE were observed in the spring and summer, which showed the presence of coarse mode particles in these seasons. An obvious increase of coarse mode particles in AVSD distribution, as well as a higher value of SSA represented considerable addition of coarse mode particles like dust into the atmosphere of Zanjan in these two seasons. Increase in AE, while a decrease in AOD was detected in the winter and fall. The presence of fine particles indicates the dominance of particles like urban-industrial aerosols from local sources especially in the winter. The Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model was utilized to calculate the Aerosol Radiative Forcing (ARF) at the Top of the Atmosphere (TOA), earth's surface and within the atmosphere. The annual averaged ARF values were -13.47 W m-2 and -36.1 W m-2 at the TOA and earth's surface, respectively, which indicate a significant cooling effect. Likewise, the ARF efficiencies at the TOA and earth's surface were -65.08 W m-2 and -158.43 W m-2, respectively. The annual mean atmospheric ARF and heating rate within the atmosphere were 22.63 W m-2 and 0.27 Kday-1 respectively, represented the warming effect within the atmosphere. Finally, a good agreement was found between AERONET retrieved ARF and SBDART simulated ARF.

  15. Diagnosing Warm Season Precipitation Over the GCIP Region from a GCM and Reanalysis

    NASA Technical Reports Server (NTRS)

    Oglesby, Robert; Marshall, Susan; Roads, John; Robertson, Franklin R.

    2000-01-01

    A 45 year simulation using a global general circulation model (GCM), the National Center for Atmospheric Research (NCAR) Community Climate Model v.3 (CCM3), forced with observed sea surface temperatures (SST), and 39 years of global National Centers for Environmental Prediction (NCEP) reanalyses were analyzed to determine Mississippi River basin warm season (May, June, July or MJJ) wet and dry year composites in the water and energy budgets. Years that have increased MJJ soil moisture over the GEWEX (Global Water and Energy Experiment) Continental Interior Project (GCIP) region also have high precipitation, lower surface temperature, decreased Bowen ratio, and reduced 500 hPa geopotential height (essentially reduced MJJ ridging). The reverse is true for years that have reduced MJJ soil moisture. Wet years are also accompanied by a general increase in moisture transport from the Gulf of Mexico into the central U.S. There is some indication (though weaker) that soil moisture may then affect precipitation and other quantities and be affected in turn by 500 hPa geopotential heights. The correlations are somewhat low, however, demonstrating the difficulty in providing definitive physical links between the remote and local effects. Analysis of two individual years with an extreme wet event (1993) and an extreme dry event (1988) yields the same general relationships as with the wet and dry composites. The composites from this study are currently serving as the basis for a series of experiments aimed at determining the predictability of the land surface and remote SST on the Mississippi River basin and other large-scale river basins.

  16. Responses of ecosystem CO 2 fluxes to short-term experimental warming and nitrogen enrichment in an Alpine meadow, northern Tibet Plateau.

    PubMed

    Zong, Ning; Shi, Peili; Jiang, Jing; Song, Minghua; Xiong, Dingpeng; Ma, Weiling; Fu, Gang; Zhang, Xianzhou; Shen, Zhenxi

    2013-01-01

    Over the past decades, the Tibetan Plateau has experienced pronounced warming, yet the extent to which warming will affect alpine ecosystems depends on how warming interacts with other influential global change factors, such as nitrogen (N) deposition. A long-term warming and N manipulation experiment was established to investigate the interactive effects of warming and N deposition on alpine meadow. Open-top chambers were used to simulate warming. N addition, warming, N addition × warming, and a control were set up. In OTCs, daytime air and soil temperature were warmed by 2.0°C and 1.6°C above ambient conditions, but soil moisture was decreased by 4.95 m(3) m(-3). N addition enhanced ecosystem respiration (Reco); nevertheless, warming significantly decreased Reco. The decline of Reco resulting from warming was cancelled out by N addition in late growing season. Our results suggested that N addition enhanced Reco by increasing soil N availability and plant production, whereas warming decreased Reco through lowering soil moisture, soil N supply potential, and suppression of plant activity. Furthermore, season-specific responses of Reco indicated that warming and N deposition caused by future global change may have complicated influence on carbon cycles in alpine ecosystems.

  17. Responses of Ecosystem CO2 Fluxes to Short-Term Experimental Warming and Nitrogen Enrichment in an Alpine Meadow, Northern Tibet Plateau

    PubMed Central

    Shi, Peili; Jiang, Jing; Song, Minghua; Xiong, Dingpeng; Ma, Weiling; Fu, Gang; Zhang, Xianzhou; Shen, Zhenxi

    2013-01-01

    Over the past decades, the Tibetan Plateau has experienced pronounced warming, yet the extent to which warming will affect alpine ecosystems depends on how warming interacts with other influential global change factors, such as nitrogen (N) deposition. A long-term warming and N manipulation experiment was established to investigate the interactive effects of warming and N deposition on alpine meadow. Open-top chambers were used to simulate warming. N addition, warming, N addition × warming, and a control were set up. In OTCs, daytime air and soil temperature were warmed by 2.0°C and 1.6°C above ambient conditions, but soil moisture was decreased by 4.95 m3 m−3. N addition enhanced ecosystem respiration (Reco); nevertheless, warming significantly decreased Reco. The decline of Reco resulting from warming was cancelled out by N addition in late growing season. Our results suggested that N addition enhanced Reco by increasing soil N availability and plant production, whereas warming decreased Reco through lowering soil moisture, soil N supply potential, and suppression of plant activity. Furthermore, season-specific responses of Reco indicated that warming and N deposition caused by future global change may have complicated influence on carbon cycles in alpine ecosystems. PMID:24459432

  18. The effect of nitrogen deposition rather than warming on CH4 flux in alpine meadows depends on precipitation variations

    NASA Astrophysics Data System (ADS)

    Chen, X.; Genxu, W.

    2017-12-01

    Uncertainties remain regarding the effects of climate warming and increasing nitrogen (N) deposition on GHG flux in alpine grasslands due to a lack of knowledge about how hydrological characteristics control GHGs fluxes. Therefore, a simulated warming and N fertilization experiment was conducted in a non-wetland (alpine meadow, AM) and a wetland (alpine swamp meadow, SM) of a permafrost region. We measured and analysed the CH4 and N2O fluxes of each treatment during two contrasting hydrological growing seasons. The results showed that: (i) warming increased the CH4 uptake in the AM but had no effect in the SM, and warming increased the N2O emissions from the AM and resulted in a change of the SM from a N2O sink into a source; (ii) N fertilization increased the CH4 uptake of the AM during the dry growing season, and had no effect on the CH4 and N2O fluxes of the SM; and (iii) the interaction between warming and N fertilization increased the CH4 uptake of the AM over the two growing seasons while increasing the CH4 uptake and N2O emissions of the SM during the dry growing season. Our results suggest that (i) the GHG flux of wetland ecosystems is more sensitive to precipitation variations than that of non-wetlands and (ii) precipitation controls the CH4 flux response to increasing N deposition of these alpine meadows.

  19. Global warming reduces plant reproductive output for temperate multi-inflorescence species on the Tibetan plateau.

    PubMed

    Liu, Yinzhan; Mu, Junpeng; Niklas, Karl J; Li, Guoyong; Sun, Shucun

    2012-07-01

    • Temperature is projected to increase more during the winter than during the summer in cold regions. The effects of winter warming on reproductive effort have not been examined for temperate plant species. • Here, we report the results of experimentally induced seasonal winter warming (0.4 and 2.4°C increases in growing and nongrowing seasons, respectively, using warmed and ambient open-top chambers in a Tibetan Plateau alpine meadow) for nine indeterminate-growing species producing multiple (single-flowered or multi-flowered) inflorescences and three determinate-growing species producing single inflorescences after a 3-yr period of warming. • Warming reduced significantly flower number and seed production per plant for all nine multi-inflorescence species, but not for the three single-inflorescence species. Warming had an insignificant effect on the fruit to flower number ratio, seed size and seed number per fruit among species. The reduction in seed production was largely attributable to the decline in flower number per plant. The flowering onset time was unaffected for nine of the 12 species. Therefore, the decline in flower production and seed production in response to winter warming probably reflects a physiological response (e.g. metabolic changes associated with flower production). • Collectively, the data indicate that global warming may reduce flower and seed production for temperate herbaceous species and will probably have a differential effect on single- vs multi-inflorescence species. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  20. The effects of seasonality on host-bat fly ecological networks in a temperate mountain cave.

    PubMed

    Rivera-García, Karina D; Sandoval-Ruiz, César A; Saldaña-Vázquez, Romeo A; Schondube, Jorge E

    2017-04-01

    Changes in the specialization of parasite-host interactions will be influenced by variations in host species composition. We evaluated this hypothesis by comparing the composition of bats and bat flies within a roost cave over one annual. Five bat and five bat fly species occupied the cave over the course of the study. Bat species composition was 40% different in the rainy season compared with the dry-cold and dry-warm seasons. Despite the incorporation of three new bat species into the cave during the rainy season, bat fly species composition was not affected by seasonality, since the bats that arrived in the rainy season only contributed one new bat fly species at a low prevalence. Bat-bat fly ecological networks were less specialized in the rainy season compared with the dry-cold and dry-warm seasons because of the increase of host overlap among bat fly species during this season. This study suggests that seasonality promote: (1) differences in host species composition, and (2) a reduction in the specialization of host-parasite ecological networks.

  1. Aridity changes in the Tibetan Plateau in a warming climate

    DOE PAGES

    Gao, Yanhong; Li, Xia; Leung, Lai-Yung R.; ...

    2015-03-10

    Desertification in the Tibetan Plateau (TP) has drawn increasing attention in the recent decades. It has been postulated as a consequence of climate aridity due to the observed warming. This study quantifies the aridity changes in the TP and attributes the changes to different climatic factors. Using the ratio of P/PET (precipitation to potential evapotranspiration) as an aridity index to indicate changes in dryness and wetness in a given area, P/PET was calculated using observed records at 83 stations in the TP, with PET calculated using the Penman–Monteith (PM) algorithm. Spatial and temporal changes of P/PET in 1979-2011 are analyzed.more » Results show that stations located in the arid and semi-arid northwestern TP are becoming significantly wetter and stations in the semi-humid southeastern TP are becoming drier, though not significantly, in the recent three decades. The aridity change patterns are significantly correlated with precipitation, sunshine duration and diurnal temperature range changes at confidence level of 99.9% from two-tail t-test. Temporal correlations also confirm the significant correlation between aridity changes with the three variables, with precipitation being the most dominant driver of P/PET changes at interannual time scale. PET changes are insignificant but negatively correlated with P/PET in the cold season. In the warm season, however, correlation between PET changes and P/PET changes are significant at confidence level of 99.9% when the cryosphere melts near the surface. Significant correlation between wind speed changes and aridity changes occurs in limited locations and months. Consistency in the climatology pattern and linear trends in surface air temperature and precipitation calculated using station data, gridded data, and nearest grid-to-stations for the TP average and across sub-basins indicate the robustness of the trends despite the large spatial heterogeneity in the TP that challenge climate monitoring.« less

  2. Seasonality of Forcing by Carbonaceous Aerosols

    NASA Astrophysics Data System (ADS)

    Habib, G.; Bond, T.; Rasch, P. J.; Coleman, D.

    2006-12-01

    Aerosols can influence the energy balance of Earth-Atmosphere system with profound effect on regional climate. Atmospheric processes, such as convection, scavenging, wet and dry deposition, govern the lifetime and location of aerosol; emissions affect its quantity and location. Both affect climate forcing. Here we investigate the effect of seasonality in emissions and atmospheric processes on radiative forcing by carbonaceous aerosols, focusing on aerosol from fossil fuel and biofuel. Because aerosol lifetime is seasonal, ignoring the seasonality of sources such as residential biofuel may introduce a bias in aerosol burden and therefore in predicted climate forcing. We present a global emission inventory of carbonaceous aerosols with seasonality, and simulate atmospheric concentrations using the Community Atmosphere Model (CAM). We discuss where and when the seasonality of emissions and atmospheric processes has strong effects on atmospheric burden, lifetime, climate forcing and aerosol optical depth (AOD). Previous work has shown that aerosol forcing is higher in summer than in winter, and has identified the importance of aerosol above cloud in determining black carbon forcing. We show that predicted cloud height is a very important factor in determining normalized radiative forcing (forcing per mass), especially in summer. This can affect the average summer radiative forcing by nearly 50%. Removal by cloud droplets is the dominant atmospheric cleansing mechanism for carbonaceous aerosols. We demonstrate the modeled seasonality of removal processes and compare the importance of scavenging by warm and cold clouds. Both types of clouds contribute significantly to aerosol removal. We estimate uncertainty in direct radiative forcing due to scavenging by tagging the aerosol which has experienced cloud interactions. Finally, seasonal variations offer an opportunity to assess modeled processes when a single process dominates variability. We identify regions where aerosol

  3. Exploration of warm-up period in conceptual hydrological modelling

    NASA Astrophysics Data System (ADS)

    Kim, Kue Bum; Kwon, Hyun-Han; Han, Dawei

    2018-01-01

    One of the important issues in hydrological modelling is to specify the initial conditions of the catchment since it has a major impact on the response of the model. Although this issue should be a high priority among modelers, it has remained unaddressed by the community. The typical suggested warm-up period for the hydrological models has ranged from one to several years, which may lead to an underuse of data. The model warm-up is an adjustment process for the model to reach an 'optimal' state, where internal stores (e.g., soil moisture) move from the estimated initial condition to an 'optimal' state. This study explores the warm-up period of two conceptual hydrological models, HYMOD and IHACRES, in a southwestern England catchment. A series of hydrologic simulations were performed for different initial soil moisture conditions and different rainfall amounts to evaluate the sensitivity of the warm-up period. Evaluation of the results indicates that both initial wetness and rainfall amount affect the time required for model warm up, although it depends on the structure of the hydrological model. Approximately one and a half months are required for the model to warm up in HYMOD for our study catchment and climatic conditions. In addition, it requires less time to warm up under wetter initial conditions (i.e., saturated initial conditions). On the other hand, approximately six months is required for warm-up in IHACRES, and the wet or dry initial conditions have little effect on the warm-up period. Instead, the initial values that are close to the optimal value result in less warm-up time. These findings have implications for hydrologic model development, specifically in determining soil moisture initial conditions and warm-up periods to make full use of the available data, which is very important for catchments with short hydrological records.

  4. Global Warming and Geographically Scalar Climatic Objects Exist: An Ontologically Realist and Object-Oriented Analysis of the Daymet TMAX Climate Summaries for North America

    NASA Astrophysics Data System (ADS)

    Jackson, C. P.

    2017-12-01

    The scientific materialist worldview, what Peter Unger refers to as the Scientiphical worldview, or Scientiphicalism, has been utterly catastrophic for mesoscale objects in general, but, with its closely associated twentieth-century formal logic, this has been especially true for notoriously vague things like climate change, coastlines, mountains and dust storms. That is, any so-called representations or references ultimately suffer the same ontological demise as their referents, no matter how well-defined their boundaries may in fact be. Against this reductionist metaphysics, climatic objects are discretized within three separate ontologically realist systems, Graham Harman's object-oriented philosophy, or ontology (OOO), Markus Gabriel's ontology of fields of sense (OFS) and Tristan Garcia's two systems and new order of time, so as to make an ontological case for any geographically scalar object, beginning with pixels, as well as any notoriously vague thing they are said to represent. Four-month overlapping TMAX seasonals were first developed from the Oak Ridge National Laboratory (ORNL) Daymet climate temperature maximum (TMAX) monthly summaries (1980-2016) for North America and segmented within Trimble's eCognition Developer using the simple and widely familiar quadtree algorithm with a scale parameter of four, in this example. The regression coefficient was then calculated for the resulting 37-year climatic objects and an equally simple classification was applied. The same segmentation and classification was applied to the Daymet annual summaries, as well, for comparison. As was expected, the mean warming and cooling trends are lowest for the annual summary TMAX climatic objects. However, the Fall (SOND) season has the largest and smallest areas of warming and cooling, respectively, and the highest mean trend for warming objects. Conversely, Spring (MAMJ) has the largest and smallest areas undergoing cooling and warming, respectively. Finally, Summer (JJAS

  5. Seasonality of fertility measured by physical activity traits in Holstein cows.

    PubMed

    Ismael, Ahmed; Strandberg, Erling; Berglund, Britt; Fogh, Anders; Løvendahl, Peter

    2016-04-01

    Seasonality of female fertility traits, including the interval from calving to first high activity (CFHA), duration of high activity episode (DHA), and strength of high activity episode (SHA) of first estrus, were studied. The physical activity traits were derived from electronic activity tags for 20,794 Holstein cows in 135 commercial Holstein herds in Denmark. Data were categorized in 3 ways: (1) into 4 seasons of calving: winter (January-March), spring (April-June), summer (July-September), and fall (October-December); (2) into 2 seasons: a cold season (October-March) and a warm season (April-September); and (3) into an increasing light season (IL; January-June), where daylight hours gradually increased, and a decreasing light season (DL; July-December), where daylight hours gradually decreased. At the phenotypic level, least squares means of CFHA were highest at 55d for cows calving in December and lowest at 31d for cows calving in September. The highest least squares means of DHA and SHA were recorded for cows calving in November and lowest for cows calving in May and June. Genetic parameters for all traits were estimated using average information-REML in a bivariate animal model that treated the same trait in different calving seasons as different traits. Heritability estimates for CFHA were highest for the winter season (0.13) and low for the other seasons (0.03-0.04), whereas heritability estimates for DHA and SHA were lowest for winter and highest for fall. Heritability estimates for CFHA for the cold season (0.17) was higher than that for the warm season (0.10). Heritability estimates of CFHA for the IL season (0.12) was higher than for the DL season (0.07), but the opposite pattern was found for DHA and SHA. Genetic correlations (rA) of CFHA between winter and summer (rA=0.34 ± 0.27), and winter and fall (rA=0.65 ± 0.20) were significantly lower than unity. The corresponding correlations of DHA and SHA between seasons were all close to unity, except

  6. Difference of the Climatological Monthly Frequency of the Explosive Cyclones in the Northwestern Part of the Pacific and the Atlantic

    NASA Astrophysics Data System (ADS)

    Tsukijihara, T.; Tomita, T.; Iwao, K.

    2015-12-01

     This study examined the climatological monthly frequency of the explosive cyclones over the northwestern(NW) part of the Pacific and the Atlantic in boreal cold season (October-April) from 1979/80 to 2012/13, using the long-term objective analysis data. The climatological monthly frequency of the NW Atlantic is on a normal distribution with a maximum in January, while it deviates from a normal distribution in the NW Pacific, in particular, the deviation is large in March. Low-level meridional temperature gradient decreases linearly from February to April in the Gulf stream region. However, the gradient is maintained through February to March to the east of Japan, and it sharply weakens in April. This feature is in good agreement with the climatological monthly frequency of the explosive cyclones in the two regions. The difference in the seasonal change of the low-level meridional temperature gradient in the two regions is caused by the positional relation of the gradient and continents. In particular, the difference of warmed area in the eastern part of the Eurasian and the North American continents causes the difference of the low-level meridional temperature gradient, and it causes the difference in the climatological monthly frequency of the explosive cyclones between the two regions from February to April.

  7. Five years of phenology observations from a mixed-grass prairie exposed to warming and elevated CO2

    USDA-ARS?s Scientific Manuscript database

    Atmospheric CO2 concentrations have been steadily increasing since the Industrial Era and contribute to concurrent increases in global temperatures. Many observational studies suggest climate warming alone contributes to a longer growing season. To determine the relative effect of warming on plant p...

  8. Global warming: it's not only size that matters

    NASA Astrophysics Data System (ADS)

    Hegerl, Gabriele C.

    2011-09-01

    impacts than temperatures that have occurred frequently due to internal climate variability. Determining when exactly temperatures enter unusual ranges may be done in many different ways (and the paper shows several, and more could be imagined), but the main result of first local emergence in low latitudes remains robust. A worrying factor is that the regions where the signal is expected to emerge first, or is already emerging are largely regions in Africa, parts of South and Central America, and the Maritime Continent; regions that are vulnerable to climate change for a variety of regions (see IPCC 2007), and regions which contribute generally little to global greenhouse gas emissions. In contrast, strong emissions of greenhouse gases occur in regions of low warming-to-variability ratio. To get even closer to the relevance of this finding for impacts, it would be interesting to place the emergence of highly unusual summer temperatures in the context not of internal variability, but in the context of variability experienced by the climate system prior to the 20th century, as, e.g. documented in palaeoclimatic reconstructions and simulated in simulations of the last millennium (see Jansen et al 2007). External forcing has moved the temperature range around more strongly for some regions and in some seasons than others. For example, while reconstructions of summer temperatures in Europe appear to show small long-term variations, winter shows deep drops in temperature in the little Ice Age and a long-term increase since then (Luterbacher et al 2004), which was at least partly caused by external forcing (Hegerl et al 2011a) and therefore 'natural variability' may be different from internal variability. A further interesting question in attempts to provide a climate-based proxy for impacts of climate change is: to what extent does the rapidity of change matter, and how does it compare to trends due to natural variability? It is reasonable to assume that fast changes impact

  9. Warming and Acidification Induced Mass Mortality of a Coastal Keystone predator

    NASA Astrophysics Data System (ADS)

    Melzner, F.; Findeisen, U.

    2016-02-01

    The Baltic Sea is characterized by low salinity and pronounced fluctuations in pCO2. On-line monitoring of pCO2 in 2014 in Kiel Fjord demonstrated occurrence of peak values of >2,000 µatm in summer and autumn and average values >750 µatm. We assessed the impacts of elevated temperature (ambient temperature, ambient +3°C) and pCO2 (500, 1,500, 2,400 µatm) on the keystone species Asterias rubens in a fully crossed long - term experiment (N=5 replicate tanks each, 1 year duration). During spring and early summer (February - June), high temperature animals ingested significantly more food and spawned significantly earlier (April 30th) than ambient acclimated animals (May 23rd). Elevated pCO2 led to comparatively minor reductions in food intake and scope for growth during that period. During summer (June - August), elevated temperature >25°C caused negative energy budgets and >95% mortality in the warm acclimated groups, while mortality was low in the ambient temperature groups. Our results indicate that A. rubens may benefit from increased temperature during colder months, yet dramatically suffer during summer heat waves in warm years. Meaningful experimental approaches to assess species vulnerability to climate change need to encompass all seasons and realistic abiotic stressor levels.

  10. Modelling the seasonality of Lyme disease risk and the potential impacts of a warming climate within the heterogeneous landscapes of Scotland.

    PubMed

    Li, Sen; Gilbert, Lucy; Harrison, Paula A; Rounsevell, Mark D A

    2016-03-01

    Lyme disease is the most prevalent vector-borne disease in the temperate Northern Hemisphere. The abundance of infected nymphal ticks is commonly used as a Lyme disease risk indicator. Temperature can influence the dynamics of disease by shaping the activity and development of ticks and, hence, altering the contact pattern and pathogen transmission between ticks and their host animals. A mechanistic, agent-based model was developed to study the temperature-driven seasonality of Ixodes ricinus ticks and transmission of Borrelia burgdorferi sensu lato across mainland Scotland. Based on 12-year averaged temperature surfaces, our model predicted that Lyme disease risk currently peaks in autumn, approximately six weeks after the temperature peak. The risk was predicted to decrease with increasing altitude. Increases in temperature were predicted to prolong the duration of the tick questing season and expand the risk area to higher altitudinal and latitudinal regions. These predicted impacts on tick population ecology may be expected to lead to greater tick-host contacts under climate warming and, hence, greater risks of pathogen transmission. The model is useful in improving understanding of the spatial determinants and system mechanisms of Lyme disease pathogen transmission and its sensitivity to temperature changes. © 2016 The Author(s).

  11. Monthly and spatially resolved black carbon emission inventory of India: uncertainty analysis

    NASA Astrophysics Data System (ADS)

    Paliwal, Umed; Sharma, Mukesh; Burkhart, John F.

    2016-10-01

    Black carbon (BC) emissions from India for the year 2011 are estimated to be 901.11 ± 151.56 Gg yr-1 based on a new ground-up, GIS-based inventory. The grid-based, spatially resolved emission inventory includes, in addition to conventional sources, emissions from kerosene lamps, forest fires, diesel-powered irrigation pumps and electricity generators at mobile towers. The emissions have been estimated at district level and were spatially distributed onto grids at a resolution of 40 × 40 km2. The uncertainty in emissions has been estimated using a Monte Carlo simulation by considering the variability in activity data and emission factors. Monthly variation of BC emissions has also been estimated to account for the seasonal variability. To the total BC emissions, domestic fuels contributed most significantly (47 %), followed by industry (22 %), transport (17 %), open burning (12 %) and others (2 %). The spatial and seasonal resolution of the inventory will be useful for modeling BC transport in the atmosphere for air quality, global warming and other process-level studies that require greater temporal resolution than traditional inventories.

  12. Solar and lunar tidal variabilities in GPS-TEC and geomagnetic field variations: Seasonal as well as during the sudden stratospheric warming of 2010

    NASA Astrophysics Data System (ADS)

    Sridharan, S.

    2017-04-01

    The Global Positioning System (GPS) deduced total electron content (TEC) data at 15°N (geomagnetic), which is the northern crest region of equatorial ionization anomaly, are used to study solar and lunar tidal variabilities during the years 2008 and 2009 and also during the 2009-2010 winter, when a major sudden stratospheric warming (SSW) event has occurred. The diurnal and semidiurnal tidal amplitudes show semiannual variation with maximum amplitudes during February-March and September-November, whereas terdiurnal tide is larger during April-September. They show significant longitudinal variability with larger (smaller) amplitudes over 250°E-150°E (200°E-250°E). Lunar semidiurnal tidal amplitudes show sporadic enhancements during northern winter months and negligible amplitudes during northern summer months. They also show notable longitudinal variabilities. The solar migrating tides DW1 and SW2 show semiannual variation with larger amplitudes during spring equinox months, whereas TW3 maximizes during northern summer. DW2 shows larger amplitudes during summer months. During the SSW, except TW3, the migrating tides DW1 and SW2 show considerable enhancements. Among solar nonmigrating tides, SW1, TW2, and DS0 show larger enhancements. Solar tides in TEC and equatorial electrojet strength over Tirunelveli vary with the time scale of 60 days during October 2009-March 2010 similar to ozone mass mixing ratio at 10 hPa, and this confirms the vital role of ozone in tidal variabilities in ionospheric parameters. Lunar tidal amplitudes in changes in horizontal component of geomagnetic field (ΔH) are larger over Tirunelveli, a station near dip equator. Solar semidiurnal tides in ΔH have larger amplitudes than lunar tides over polar stations, Mawson and Godhavn.Plain Language SummaryIn this paper, the variations of solar and lunar tides in a few ionospheric parameters during the years 2008 and 2009 and during a disturbed</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4711884','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4711884"><span>Cold <span class="hlt">season</span> emissions dominate the Arctic tundra methane budget</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zona, Donatella; Gioli, Beniamino; Lindaas, Jakob; Wofsy, Steven C.; Miller, Charles E.; Dinardo, Steven J.; Dengel, Sigrid; Sweeney, Colm; Karion, Anna; Chang, Rachel Y.-W.; Henderson, John M.; Murphy, Patrick C.; Goodrich, Jordan P.; Moreaux, Virginie; Liljedahl, Anna; Watts, Jennifer D.; Kimball, John S.; Lipson, David A.; Oechel, Walter C.</p> <p>2016-01-01</p> <p>Arctic terrestrial ecosystems are major global sources of methane (CH4); hence, it is important to understand the <span class="hlt">seasonal</span> and climatic controls on CH4 emissions from these systems. Here, we report year-round CH4 emissions from Alaskan Arctic tundra eddy flux sites and regional fluxes derived from aircraft data. We find that emissions during the cold <span class="hlt">season</span> (September to May) account for ≥50% of the annual CH4 flux, with the highest emissions from noninundated upland tundra. A major fraction of cold <span class="hlt">season</span> emissions occur during the “zero curtain” period, when subsurface soil temperatures are poised near 0 °C. The zero curtain may persist longer than the growing <span class="hlt">season</span>, and CH4 emissions are enhanced when the duration is extended by a deep thawed layer as can occur with thick snow cover. Regional scale fluxes of CH4 derived from aircraft data demonstrate the large spatial extent of late <span class="hlt">season</span> CH4 emissions. Scaled to the circumpolar Arctic, cold <span class="hlt">season</span> fluxes from tundra total 12 ± 5 (95% confidence interval) Tg CH4 y−1, ∼25% of global emissions from extratropical wetlands, or ∼6% of total global wetland methane emissions. The dominance of late-<span class="hlt">season</span> emissions, sensitivity to soil environmental conditions, and importance of dry tundra are not currently simulated in most global climate models. Because Arctic <span class="hlt">warming</span> disproportionally impacts the cold <span class="hlt">season</span>, our results suggest that higher cold-<span class="hlt">season</span> CH4 emissions will result from observed and predicted increases in snow thickness, active layer depth, and soil temperature, representing important positive feedbacks on climate <span class="hlt">warming</span>. PMID:26699476</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1237500-cold-season-emissions-dominate-arctic-tundra-methane-budget','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1237500-cold-season-emissions-dominate-arctic-tundra-methane-budget"><span>Cold <span class="hlt">season</span> emissions dominate the Arctic tundra methane budget</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Zona, Donatella; Gioli, Beniamino; Commane, Róisín; ...</p> <p>2015-12-22</p> <p>Arctic terrestrial ecosystems are major global sources of methane (CH 4); hence, it is important to understand the <span class="hlt">seasonal</span> and climatic controls on CH 4 emissions from these systems. Here, we report year-round CH 4 emissions from Alaskan Arctic tundra eddy flux sites and regional fluxes derived from aircraft data. We find that emissions during the cold <span class="hlt">season</span> (September to May) account for ≥ 50% of the annual CH 4 flux, with the highest emissions from noninundated upland tundra. A major fraction of cold <span class="hlt">season</span> emissions occur during the “zero curtain” period, when subsurface soil temperatures are poised near 0more » °C. The zero curtain may persist longer than the growing <span class="hlt">season</span>, and CH 4 emissions are enhanced when the duration is extended by a deep thawed layer as can occur with thick snow cover. Regional scale fluxes of CH 4 derived from aircraft data demonstrate the large spatial extent of late <span class="hlt">season</span> CH 4 emissions. Scaled to the circumpolar Arctic, cold <span class="hlt">season</span> fluxes from tundra total 12 ± 5 (95% confidence interval) Tg CH 4 y –1, ~25% of global emissions from extratropical wetlands, or ~6% of total global wetland methane emissions. Here, the dominance of late-<span class="hlt">season</span> emissions, sensitivity to soil environmental conditions, and importance of dry tundra are not currently simulated in most global climate models. Because Arctic <span class="hlt">warming</span> disproportionally impacts the cold <span class="hlt">season</span>, our results suggest that higher cold-<span class="hlt">season</span> CH 4 emissions will result from observed and predicted increases in snow thickness, active layer depth, and soil temperature, representing important positive feedbacks on climate <span class="hlt">warming</span>.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26506548','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26506548"><span>The cost of feeding bred dairy heifers on native <span class="hlt">warm-season</span> grasses and harvested feedstuffs.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lowe, J K; Boyer, C N; Griffith, A P; Waller, J C; Bates, G E; Keyser, P D; Larson, J A; Holcomb, E</p> <p>2016-01-01</p> <p>Heifer rearing is one of the largest production expenses for dairy cattle operations, which is one reason milking operations outsource heifer rearing to custom developers. The cost of harvested feedstuffs is a major expense in heifer rearing. A possible way to lower feed costs is to graze dairy heifers, but little research exists on this topic in the mid-south United States. The objectives of this research were to determine the cost of feeding bred dairy heifers grazing native <span class="hlt">warm-season</span> grasses (NWSG), with and without legumes, and compare the cost of grazing with the cost of rearing heifers using 3 traditional rations. The 3 rations were corn silage with soybean meal, corn silage with dry distillers grain, and a wet distillers grain-based ration. Bred Holstein heifers between 15- and 20-mo-old continuously grazed switchgrass (SG), SG with red clover (SG+RC), a big bluestem and Indiangrass mixture (BBIG), and BBIG with red clover (BBIG+RC) in Tennessee during the summer <span class="hlt">months</span>. Total grazing days were calculated for each NWSG to determine the average cost/animal per grazing day. The average daily gain (ADG) was calculated for each NWSG to develop 3 harvested feed rations that would result in the same ADG over the same number of grazing day as each NWSG treatment. The average cost/animal per grazing day was lowest for SG ($0.48/animal/grazing d) and highest for BBIG+RC ($1.10/animal/grazing d). For both BBIG and SG, legumes increased the average cost/animal per grazing day because grazing days did not increase enough to account for the additional cost of the legumes. No difference was observed in ADG for heifers grazing BBIG (0.85 kg/d) and BBIG+RC (0.94 kg/d), and no difference was observed in ADG for heifers grazing SG (0.71 kg/d) and SG+RC (0.70 kg/d). However, the ADG for heifers grazing SG and SG+RC was lower than the ADG for heifers grazing either BBIG or BBIG+RC. The average cost/animal per grazing day was lower for all NWSG treatments than the average cost</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMGC43C0746W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMGC43C0746W"><span>Isolating the Effects of the <span class="hlt">Warming</span> Trend from the General Climate Change in Water Resources: California Case</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, J.; Yin, H.; Chung, F.</p> <p>2008-12-01</p> <p>While the population growth, the future land use change, and the desire for better environmental preservation and protection are adding up pressure on water resources management in California, California is facing an extra challenge of addressing potential climate change impacts on water supple and demand in California. The concerns on water facilities planning and flood control caused by climate change include modified precipitation patterns, changes in snow levels and runoff patterns due to increased air temperatures. Although long-term climate projections are largely uncertain, there appears to be a strong consistency in predicting the <span class="hlt">warming</span> trend of future surface temperature, and the resulting shift in the <span class="hlt">seasonal</span> patterns of runoff. However, projected changes in precipitation (wetting or drying), which control annual runoff, are far less certain. This paper attempts to separate the effects of <span class="hlt">warming</span> trend from the effects of precipitation trend on water planning especially in California where reservoir operations are more sensitive to <span class="hlt">seasonal</span> patterns of runoff than to the total annual runoff. The water resources systems planning model, CALSIM2, is used to evaluate climate change impact on water resource management in California. Rather than directly ingesting estimated streamflows from climate model projections into CALSIM2, a three step perturbation ratio method is proposed to introduce climate change impact into the planning model. Firstly, <span class="hlt">monthly</span> perturbation ratio of projected <span class="hlt">monthly</span> inflow to simulated historical <span class="hlt">monthly</span> inflow is applied to observed historical <span class="hlt">monthly</span> inflow to generate climate change inflows to major dams and reservoirs. To isolate the effects of <span class="hlt">warming</span> trend on water resources, a further annual inflow adjustment is applied to the inflows generated in step one to preserve the volume of the observed annual inflow. To re-introduce the effects of precipitation trend on water resources, an additional inflow trend adjustment is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.B51P..06M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.B51P..06M"><span>Spring Temperatures Alone Cannot Explain Timing of Budburst of Boreal-Temperate Tree Species under Experimental <span class="hlt">Warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Montgomery, R. A.; Reich, P. B.; Rich, R. L.; Stefanski, A.</p> <p>2011-12-01</p> <p>Phenology, the timing of <span class="hlt">seasonal</span> biological events such as budburst, blossom dates, bird migration and insect development, is critical to understanding species interactions (e.g. pollination, herbivory); determines growing <span class="hlt">season</span> length in many (i.e. <span class="hlt">seasonal</span>) terrestrial ecosystems; and can play a role in determining species range limits. There is ample evidence that plant and animal phenology has changed in recent decades. For trees in <span class="hlt">seasonally</span> cold climates, change is most commonly manifested as earlier budburst, likely caused by earlier onset of <span class="hlt">warming</span> temperatures in spring. Indeed, it is often assumed that one of the major phenological responses of temperate and boreal forest ecosystems to climate change will be earlier leafing and concomitantly, a longer growing <span class="hlt">season</span>. However, spring <span class="hlt">warming</span> interacts with other factors such as winter chilling and photoperiod to determine timing of spring leafing. For example, warmer winters could reduce the duration and amount of chilling experienced by dormant buds and lead to delayed budburst. Despite knowledge that such interactions exist, we know little about the interactive mechanisms by which various cues influence budburst in forest tree species or whether species differ in sensitivity to those cues. This gap hinders our ability to predict phenological responses and their ecological impacts under future climate scenarios. Over the past three years, we have conducted studies of leafing phenology, germination, photosynthesis, respiration, and growth of seedlings of ten boreal-temperate tree species subjected to experimental <span class="hlt">warming</span> using infrared heat lamps and soil heating cables. Seedlings were planted into plots receiving ambient, +1.8°C or +3.6°C temperature treatments in open, aspen forest at the Cloquet Forestry Center, Cloquet, MN, USA (46°31' N, 92°30' W, 386 m a.s.l.; 4.5°C MAT, 807 mm MAP). While all species responded to <span class="hlt">warming</span> by advancing the absolute date of budburst, several lines of evidence</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGC11F1081S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGC11F1081S"><span>Endurance of larch forest ecosystems in eastern Siberia under <span class="hlt">warming</span> trends</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sato, H.; Iwahana, G.; Ohta, T.</p> <p>2015-12-01</p> <p>The larch (Larix spp.) forest in eastern Siberia is the world's largest coniferous forest. However, its existence depends on near-surface permafrost, which increases water availability for trees, and the boundary of the forest closely follows the permafrost zone. Therefore, the degradation of near-surface permafrost due to forecasted <span class="hlt">warming</span> trends during the 21st century is expected to affect the larch forest in Siberia. However, predictions of how <span class="hlt">warming</span> trends will affect this forest vary greatly, and many uncertainties remain about land-atmospheric interactions within the ecosystem. We developed an integrated land surface model to analyze how the Siberian larch forest will react to current <span class="hlt">warming</span> trends. This model analyzed interactions between vegetation dynamics and thermo-hydrology and showed that, under climatic conditions predicted by the Intergovernmental Panel on Climate Change (IPCC) Representative Concentration Pathway (RCP) scenarios 2.6 and 8.5, annual larch net primary production (NPP) increased about 2 and 3 times, respectively, by the end of 21st century compared with that in the 20th century. Soil water content during larch growing <span class="hlt">season</span> showed no obvious trend, even after decay of surface permafrost and accompanying sub-surface runoff. A sensitivity test showed that the forecasted <span class="hlt">warming</span> and pluvial trends extended leafing days of larches and reduced water shortages during the growing <span class="hlt">season</span>, thereby increasing productivity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.H52D..01G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.H52D..01G"><span><span class="hlt">Seasonal</span> hydroclimatic impacts of Brazilian sugar cane expansion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Georgescu, M.; Lobell, D. B.; Field, C. B.; Mahalov, A.</p> <p>2012-12-01</p> <p>Brazil is the leading producer of sugar cane in the world with roughly half used for ethanol production. Because of suitable climatic growing conditions, the majority of biofuel production is derived from sugar plantations in southeastern states. Anticipated increases in global demand for biofuels are expected to lead to future sugar cane expansion extending into Brazilian pasturelands and native cerrado. Prior to undergoing large-scale expansion an evaluation of impacts on the region's hydroclimate is warranted. Using a suite of multi-year ensemble-based simulations with the WRF modeling system, we quantify hydroclimatic consequences of sugar cane expansion across portions of south-central Brazil. Conversion from current land use to sugar cane causes opposing <span class="hlt">seasonal</span> impacts on near-surface temperature. Proggresively greater cooling is simulated during the course of the growing <span class="hlt">season</span>, followed by an abrupt <span class="hlt">warming</span> shift post-harvest. Although <span class="hlt">seasonal</span> impacts on near-surface temperature are significant, with cooling of 1C occurring during the peak of the growing <span class="hlt">season</span> followed by <span class="hlt">warming</span> of similar magnitude, impacts are small when annually averaged. Ensemble mean differences between the imposed sugar cane expansion and non-expansion scenario are suggestive of a drying precipitation trend, yet large uncertainty among individual members precludes definitive statements about impacts on the region's rainfall.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26PSL.449..418B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26PSL.449..418B"><span>Last interglacial temperature <span class="hlt">seasonality</span> reconstructed from tropical Atlantic corals</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brocas, William M.; Felis, Thomas; Obert, J. Christina; Gierz, Paul; Lohmann, Gerrit; Scholz, Denis; Kölling, Martin; Scheffers, Sander R.</p> <p>2016-09-01</p> <p>Reconstructions of last interglacial (LIG, MIS 5e, ∼127-117 ka) climate offer insights into the natural response and variability of the climate system during a period partially analogous to future climate change scenarios. We present well preserved fossil corals (Diploria strigosa) recovered from the southern Caribbean island of Bonaire (Caribbean Netherlands). These have been precisely dated by the 230Th/U-method to between 130 and 120 ka ago. Annual banding of the coral skeleton enabled construction of time windows of <span class="hlt">monthly</span> resolved strontium/calcium (Sr/Ca) temperature proxy records. In conjunction with a previously published 118 ka coral record, our eight records of up to 37 years in length, cover a total of 105 years within the LIG period. From these, sea surface temperature (SST) <span class="hlt">seasonality</span> and variability in the tropical North Atlantic Ocean is reconstructed. We detect similar to modern SST <span class="hlt">seasonality</span> of ∼2.9 °C during the early (130 ka) and the late LIG (120-118 ka). However, within the mid-LIG, a significantly higher than modern SST <span class="hlt">seasonality</span> of 4.9 °C (at 126 ka) and 4.1 °C (at 124 ka) is observed. These findings are supported by climate model simulations and are consistent with the evolving amplitude of orbitally induced changes in <span class="hlt">seasonality</span> of insolation throughout the LIG, irrespective of wider climatic instabilities that characterised this period. The climate model simulations suggest that the SST <span class="hlt">seasonality</span> changes documented in our LIG coral Sr/Ca records are representative of larger regions within the tropical North Atlantic. These simulations also suggest that the reconstructed SST <span class="hlt">seasonality</span> increase during the mid-LIG is caused primarily by summer <span class="hlt">warming</span>. A 124 ka old coral documents, for the first time, evidence of decadal SST variability in the tropical North Atlantic during the LIG, akin to that observed in modern instrumental records.</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" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110007965','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110007965"><span><span class="hlt">Warm</span> <span class="hlt">Season</span> Subseasonal Variability and Climate Extremes in the Northern Hemisphere: The Role of Stationary Rossby Waves</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schubert, Siegfried; Wang, Hailan; Suarez, Max</p> <p>2010-01-01</p> <p>This study examines the nature of boreal summer subseasonal atmospheric variability based on the new NASA Modern-Era Retrospective analysis for Research and Applications (MERRA) for the period 1979-2010. An analysis of the June, July and August subseasonal 250hPa v-wind anomalies shows distinct Rossby wave-like structures that appear to be guided by the mean jets. On <span class="hlt">monthly</span> subseasonal time scales, the leading waves (the first 10 rotated empirical orthogonal functions or REOFs of the 250hPa v-wind) explain about 50% of the Northern Hemisphere vwind variability, and account for more than 30% (60%) of the precipitation (surface temperature) variability over a number of regions of the northern middle and high latitudes, including the U.S. northern Great Plains, parts of Canada, Europe, and Russia. The first REOF in particular, consists of a Rossby wave that extends across northern Eurasia where it is a dominant contributor to <span class="hlt">monthly</span> surface temperature and precipitation variability, and played an important role in the 2003 European and 2010 Russian heat waves. While primarily subseasonal in nature, the Rossby waves can at times have a substantial <span class="hlt">seasonal</span> mean component. This is exemplified by REOF 4 which played a major role in the development of the most intense anomalies of the U.S. 1988 drought (during June) and the 1993 flooding (during July), though differed in the latter event by also making an important contribution to the <span class="hlt">seasonal</span> mean anomalies. A stationary wave model (SWM) is used to reproduce some of the basic features of the observed waves and provide insight into the nature of the forcing. In particular, the responses to a set of idealized forcing functions are used to map the optimal forcing patterns of the leading waves. Also, experiments to reproduce the observed waves with the SWM using MERRA-based estimates of the forcing indicate that the wave forcing is dominated by sub-<span class="hlt">monthly</span> vorticity transients.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23208757','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23208757"><span><span class="hlt">Seasonal</span> trends of atmospheric nitrogen dioxide and sulfur dioxide over North Santa Clara, Cuba.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alejo, Daniellys; Morales, Mayra C; de la Torre, Jorge B; Grau, Ricardo; Bencs, László; Van Grieken, René; Van Espen, Piet; Sosa, Dismey; Nuñez, Vladimir</p> <p>2013-07-01</p> <p>Atmospheric nitrogen dioxide (NO2) and sulfur dioxide (SO2) levels were monitored simultaneously by means of Radiello passive samplers at six sites of Santa Clara city, Cuba, in the cold and the <span class="hlt">warm</span> <span class="hlt">seasons</span> in 2010. The dissolved ionic forms of NO2 and SO2 as nitrate and sulfite plus sulfate, respectively, were determined by means of ion chromatography. Analysis of NO2 as nitrite was also performed by UV-Vis spectrophotometry. For NO2, significant t tests show good agreement between the results of IC and UV-Vis methods. The NO2 and SO2 concentrations peaked in the cold <span class="hlt">season</span>, while their minimum levels were experienced in the <span class="hlt">warm</span> <span class="hlt">season</span>. The pollutant levels do not exceed the maximum allowable limit of the Cuban Standard 39:1999, i.e., 40 μg/m(3) and 50 μg/m(3) for NO2 and SO2, respectively. The lowest pollutant concentrations obtained in the <span class="hlt">warm</span> <span class="hlt">season</span> can be attributed to an increase in their removal via precipitation (scavenging) while to the decreased traffic density and industrial emission during the summer holidays (e.g., July and August).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhDT.......301S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhDT.......301S"><span>The influence of the Great Lakes on MCS formation and development in the <span class="hlt">warm</span> <span class="hlt">season</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Srock, Alan F.</p> <p></p> <p>This study focuses on how near-surface thermal boundaries that form near the Great Lakes during the <span class="hlt">warm</span> <span class="hlt">season</span> can contribute to the formation of mesoscale convective systems (MCSs). Differential heating across land-water interfaces can create a cold dome of air over the lake; convection may develop when the relatively-cold dome of air becomes deep enough to enable air parcels that intersect these boundaries to reach their level of free convection. A radar-based climatology of MCS events surrounding the Great Lakes for 2002-2005 showed that MCSs frequently form in the vicinity of the Great Lakes. Composites of MCS events over the Great Lakes and in sub-regions defined by proximity to a Great Lake showed that the most important synoptic-scale precursor for MCS initiation is the presence of a low-level moisture plume, which is often (but not always) provided by a low-level jet (LLJ). Case studies of two MCSs that formed along the eastern shore of Lake Michigan showed how differential heating across the land-lake interface enabled the development of a near-surface mesoscale thermal boundary along which forced ascent was able to trigger convection. A third case study of an MCS that formed along the southern shore of Lake Superior showed that a strong land-lake thermal boundary provided a focus for long-lived MCS development beneath a plume of <span class="hlt">warm</span>, moist air along the LLJ. High-resolution WRF-modeling studies were used to test the effect of the presence of a Great Lake on land-lake thermal boundary development and MCS generation. In one pair of simulations, differential heating in the control run created an over-lake cold dome that grew stronger and deeper during the day. Removing the lake removed the differential heating, so the no-lake run became comparatively warmer and moister in the lowest 1000 m over the "lake". Convection focused and organized along the near-lake mesoscale boundary in the control run, but was less organized and forced by larger-scale processes</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JSR....79...50H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JSR....79...50H"><span><span class="hlt">Seasonal</span> variability of rocky reef fish assemblages: Detecting functional and structural changes due to fishing effects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Henriques, Sofia; Pais, Miguel Pessanha; Costa, Maria José; Cabral, Henrique Nogueira</p> <p>2013-05-01</p> <p>The present study analyzed the effects of <span class="hlt">seasonal</span> variation on the stability of fish-based metrics and their capability to detect changes in fish assemblages, which is yet poorly understood despite the general idea that guilds are more resilient to natural variability than species abundances. Three zones subject to different levels of fishing pressure inside the Arrábida Marine Protected Area (MPA) were sampled <span class="hlt">seasonally</span>. The results showed differences between <span class="hlt">warm</span> (summer and autumn) and cold (winter and spring) <span class="hlt">seasons</span>, with the autumn clearly standing out. In general, the values of the metrics density of juveniles, density of invertebrate feeders and density of omnivores increased in <span class="hlt">warm</span> <span class="hlt">seasons</span>, which can be attributed to differences in recruitment patterns, spawning migrations and feeding activity among <span class="hlt">seasons</span>. The density of generalist/opportunistic individuals was sensitive to the effect of fishing, with higher values at zones with the lowest level of protection, while the density of individuals with high commercial value only responded to fishing in the autumn, due to a cumulative result of both juveniles and adults abundances during this <span class="hlt">season</span>. Overall, this study showed that <span class="hlt">seasonal</span> variability affects structural and functional features of the fish assemblage and that might influence the detection of changes as a result of anthropogenic pressures. The choice of a specific <span class="hlt">season</span>, during <span class="hlt">warm</span> sea conditions after the spawning period (July-October), seems to be more adequate to assess changes on rocky-reef fish assemblages.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5101614','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5101614"><span><span class="hlt">Seasonal</span> regulation of herbivory and nutrient effects on macroalgal recruitment and succession in a Florida coral reef</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Collado-Vides, Ligia; Burkepile, Deron E.</p> <p>2016-01-01</p> <p>Herbivory and nutrient enrichment are drivers of benthic dynamics of coral reef macroalgae; however, their impact may vary <span class="hlt">seasonally</span>. In this study we evaluated the effects of herbivore pressure, nutrient availability and potential propagule supply on <span class="hlt">seasonal</span> recruitment and succession of macroalgal communities on a Florida coral reef. Recruitment tiles, replaced every three <span class="hlt">months</span>, and succession tiles, kept in the field for nine <span class="hlt">months</span>, were established in an ongoing factorial nutrient enrichment-herbivore exclusion experiment. The ongoing experiment had already created very different algal communities across the different herbivory and nutrient treatments. We tracked algal recruitment, species richness, and species abundance through time. Our results show <span class="hlt">seasonal</span> variation in the effect of herbivory and nutrient availability on recruitment of coral reef macroalgae. In the spring, when there was higher macroalgal species richness and abundance of recruits, herbivory appeared to have more control on macroalgal community structure than did nutrients. In contrast, there was no effect of either herbivory or nutrient enrichment on macroalgal communities on recruitment tiles in cooler <span class="hlt">seasons</span>. The abundance of recruits on tiles was positively correlated with the abundance of algal in the ongoing, established experiment, suggesting that propagule abundance is likely a strong influence on algal recruitment and early succession. Results of the present study suggest that abundant herbivorous fishes control recruitment and succession of macroalgae, particularly in the <span class="hlt">warm</span> <span class="hlt">season</span> when macroalgal growth is higher. However, herbivory appears less impactful on algal recruitment and community dynamics in cooler <span class="hlt">seasons</span>. Ultimately, our data suggest that the timing of coral mortality (e.g., summer vs. winter mortality) and freeing of benthic space may strongly influence the dynamics of algae that colonize open space. PMID:27833810</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27833810','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27833810"><span><span class="hlt">Seasonal</span> regulation of herbivory and nutrient effects on macroalgal recruitment and succession in a Florida coral reef.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Duran, Alain; Collado-Vides, Ligia; Burkepile, Deron E</p> <p>2016-01-01</p> <p>Herbivory and nutrient enrichment are drivers of benthic dynamics of coral reef macroalgae; however, their impact may vary <span class="hlt">seasonally</span>. In this study we evaluated the effects of herbivore pressure, nutrient availability and potential propagule supply on <span class="hlt">seasonal</span> recruitment and succession of macroalgal communities on a Florida coral reef. Recruitment tiles, replaced every three <span class="hlt">months</span>, and succession tiles, kept in the field for nine <span class="hlt">months</span>, were established in an ongoing factorial nutrient enrichment-herbivore exclusion experiment. The ongoing experiment had already created very different algal communities across the different herbivory and nutrient treatments. We tracked algal recruitment, species richness, and species abundance through time. Our results show <span class="hlt">seasonal</span> variation in the effect of herbivory and nutrient availability on recruitment of coral reef macroalgae. In the spring, when there was higher macroalgal species richness and abundance of recruits, herbivory appeared to have more control on macroalgal community structure than did nutrients. In contrast, there was no effect of either herbivory or nutrient enrichment on macroalgal communities on recruitment tiles in cooler <span class="hlt">seasons</span>. The abundance of recruits on tiles was positively correlated with the abundance of algal in the ongoing, established experiment, suggesting that propagule abundance is likely a strong influence on algal recruitment and early succession. Results of the present study suggest that abundant herbivorous fishes control recruitment and succession of macroalgae, particularly in the <span class="hlt">warm</span> <span class="hlt">season</span> when macroalgal growth is higher. However, herbivory appears less impactful on algal recruitment and community dynamics in cooler <span class="hlt">seasons</span>. Ultimately, our data suggest that the timing of coral mortality (e.g., summer vs. winter mortality) and freeing of benthic space may strongly influence the dynamics of algae that colonize open space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.9989R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.9989R"><span><span class="hlt">Seasonality</span> of Arctic Mediterranean Exchanges</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rieper, Christoph; Quadfasel, Detlef</p> <p>2015-04-01</p> <p>The Arctic Mediterranean communicates through a number of passages with the Atlantic and the Pacific Oceans. Most of the volume exchange happens at the Greenland-Scotland-Ridge: <span class="hlt">warm</span> and saline Atlantic Water flows in at the surface, cold, dense Overflow Water flows back at the bottom and fresh and cold Polar Water flows out along the East Greenland coast. All surface inflows show a <span class="hlt">seasonal</span> signal whereas only the outflow through the Faroe Bank Channel exhibits significant <span class="hlt">seasonality</span>. Here we present a quantification of the <span class="hlt">seasonal</span> cycle of the exchanges across the Greenland-Scotland ridge based on volume estimates of the in- and outflows within the last 20 years (ADCP and altimetry). Our approach is comparatistic: we compare different properties of the <span class="hlt">seasonal</span> cycle like the strength or the phase between the different in- and outflows. On the <span class="hlt">seasonal</span> time scale the in- and outflows across the Greenland-Scotland-Ridge are not balanced. The net flux thus has to be balanced by the other passages on the Canadian Archipelago, Bering Strait as well as runoff from land.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1193634','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1193634"><span>Microclimatic performance of a free-air <span class="hlt">warming</span> and CO₂ enrichment experiment in windy Wyoming, USA</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>LeCain, Daniel; Smith, David; Morgan, Jack</p> <p></p> <p>In order to plan for global changing climate experiments are being conducted in many countries, but few have monitored the effects of the climate change treatments (<span class="hlt">warming</span>, elevated CO₂) on the experimental plot microclimate. During three years of an eight year study with year-round feedback-controlled infra-red heater <span class="hlt">warming</span> (1.5/3.0°C day/night) and growing <span class="hlt">season</span> free-air CO₂ enrichment (600 ppm) in the mixed-grass prairie of Wyoming, USA, we monitored soil, leaf, canopy-air, above-canopy-air temperatures and relative humidity of control and treated experimental plots and evaluated ecologically important temperature differentials. Leaves were <span class="hlt">warmed</span> somewhat less than the target settings (1.1 & 1.5°C day/night)more » but soil was <span class="hlt">warmed</span> more creating an average that matched the target settings extremely well both during the day and night plus the summer and winter. The site typically has about 50% bare or litter covered soil, therefore soil heat transfer is more critical than in dense canopy ecosystems. The Wyoming site commonly has strong winds (5 ms⁻¹ average) and significant daily and <span class="hlt">seasonal</span> temperature fluctuations (as much as 30°C daily) but the <span class="hlt">warming</span> system was nearly always able to maintain the set temperatures regardless of abiotic variation. The within canopy-air was only slightly <span class="hlt">warmed</span> and above canopy-air was not <span class="hlt">warmed</span> by the system, therefore convective <span class="hlt">warming</span> was minor. Elevated CO₂ had no direct effect nor interaction with the <span class="hlt">warming</span> treatment on microclimate. Relative humidity within the plant canopy was only slightly reduced by <span class="hlt">warming</span>. Soil water content was reduced by <span class="hlt">warming</span> but increased by elevated CO₂. This study demonstrates the importance of monitoring the microclimate in manipulative field global change experiments so that critical physiological and ecological conclusions can be determined. Highly variable energy demand fluctuations showed that passive IR heater <span class="hlt">warming</span> systems will not maintain desired <span class="hlt">warming</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1193634-microclimatic-performance-free-air-warming-co-enrichment-experiment-windy-wyoming-usa','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1193634-microclimatic-performance-free-air-warming-co-enrichment-experiment-windy-wyoming-usa"><span>Microclimatic performance of a free-air <span class="hlt">warming</span> and CO₂ enrichment experiment in windy Wyoming, USA</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>LeCain, Daniel; Smith, David; Morgan, Jack; ...</p> <p>2015-02-06</p> <p>In order to plan for global changing climate experiments are being conducted in many countries, but few have monitored the effects of the climate change treatments (<span class="hlt">warming</span>, elevated CO₂) on the experimental plot microclimate. During three years of an eight year study with year-round feedback-controlled infra-red heater <span class="hlt">warming</span> (1.5/3.0°C day/night) and growing <span class="hlt">season</span> free-air CO₂ enrichment (600 ppm) in the mixed-grass prairie of Wyoming, USA, we monitored soil, leaf, canopy-air, above-canopy-air temperatures and relative humidity of control and treated experimental plots and evaluated ecologically important temperature differentials. Leaves were <span class="hlt">warmed</span> somewhat less than the target settings (1.1 & 1.5°C day/night)more » but soil was <span class="hlt">warmed</span> more creating an average that matched the target settings extremely well both during the day and night plus the summer and winter. The site typically has about 50% bare or litter covered soil, therefore soil heat transfer is more critical than in dense canopy ecosystems. The Wyoming site commonly has strong winds (5 ms⁻¹ average) and significant daily and <span class="hlt">seasonal</span> temperature fluctuations (as much as 30°C daily) but the <span class="hlt">warming</span> system was nearly always able to maintain the set temperatures regardless of abiotic variation. The within canopy-air was only slightly <span class="hlt">warmed</span> and above canopy-air was not <span class="hlt">warmed</span> by the system, therefore convective <span class="hlt">warming</span> was minor. Elevated CO₂ had no direct effect nor interaction with the <span class="hlt">warming</span> treatment on microclimate. Relative humidity within the plant canopy was only slightly reduced by <span class="hlt">warming</span>. Soil water content was reduced by <span class="hlt">warming</span> but increased by elevated CO₂. This study demonstrates the importance of monitoring the microclimate in manipulative field global change experiments so that critical physiological and ecological conclusions can be determined. Highly variable energy demand fluctuations showed that passive IR heater <span class="hlt">warming</span> systems will not maintain desired <span class="hlt">warming</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26982730','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26982730"><span>Boreal and temperate trees show strong acclimation of respiration to <span class="hlt">warming</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Reich, Peter B; Sendall, Kerrie M; Stefanski, Artur; Wei, Xiaorong; Rich, Roy L; Montgomery, Rebecca A</p> <p>2016-03-31</p> <p>Plant respiration results in an annual flux of carbon dioxide (CO2) to the atmosphere that is six times as large as that due to the emissions from fossil fuel burning, so changes in either will impact future climate. As plant respiration responds positively to temperature, a <span class="hlt">warming</span> world may result in additional respiratory CO2 release, and hence further atmospheric <span class="hlt">warming</span>. Plant respiration can acclimate to altered temperatures, however, weakening the positive feedback of plant respiration to rising global air temperature, but a lack of evidence on long-term (weeks to years) acclimation to climate <span class="hlt">warming</span> in field settings currently hinders realistic predictions of respiratory release of CO2 under future climatic conditions. Here we demonstrate strong acclimation of leaf respiration to both experimental <span class="hlt">warming</span> and <span class="hlt">seasonal</span> temperature variation for juveniles of ten North American tree species growing for several years in forest conditions. Plants grown and measured at 3.4 °C above ambient temperature increased leaf respiration by an average of 5% compared to plants grown and measured at ambient temperature; without acclimation, these increases would have been 23%. Thus, acclimation eliminated 80% of the expected increase in leaf respiration of non-acclimated plants. Acclimation of leaf respiration per degree temperature change was similar for experimental <span class="hlt">warming</span> and <span class="hlt">seasonal</span> temperature variation. Moreover, the observed increase in leaf respiration per degree increase in temperature was less than half as large as the average reported for previous studies, which were conducted largely over shorter time scales in laboratory settings. If such dampening effects of leaf thermal acclimation occur generally, the increase in respiration rates of terrestrial plants in response to climate <span class="hlt">warming</span> may be less than predicted, and thus may not raise atmospheric CO2 concentrations as much as anticipated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25902893','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25902893"><span>Moisture rivals temperature in limiting photosynthesis by trees establishing beyond their cold-edge range limit under ambient and <span class="hlt">warmed</span> conditions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Moyes, Andrew B; Germino, Matthew J; Kueppers, Lara M</p> <p>2015-09-01</p> <p>Climate change is altering plant species distributions globally, and <span class="hlt">warming</span> is expected to promote uphill shifts in mountain trees. However, at many cold-edge range limits, such as alpine treelines in the western United States, tree establishment may be colimited by low temperature and low moisture, making recruitment patterns with <span class="hlt">warming</span> difficult to predict. We measured response functions linking carbon (C) assimilation and temperature- and moisture-related microclimatic factors for limber pine (Pinus flexilis) seedlings growing in a heating × watering experiment within and above the alpine treeline. We then extrapolated these response functions using observed microclimate conditions to estimate the net effects of <span class="hlt">warming</span> and associated soil drying on C assimilation across an entire growing <span class="hlt">season</span>. Moisture and temperature limitations were each estimated to reduce potential growing <span class="hlt">season</span> C gain from a theoretical upper limit by 15-30% (c. 50% combined). <span class="hlt">Warming</span> above current treeline conditions provided relatively little benefit to modeled net assimilation, whereas assimilation was sensitive to either wetter or drier conditions. Summer precipitation may be at least as important as temperature in constraining C gain by establishing subalpine trees at and above current alpine treelines as <span class="hlt">seasonally</span> dry subalpine and alpine ecosystems continue to <span class="hlt">warm</span>. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990018501','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990018501"><span>Global <span class="hlt">Warming</span> on Triton</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Elliot, J. L.; Hammel, H. B.; Wasserman, L. H.; Franz, O. G.; McDonald, S. W.; Person, M. J.; Olkin, C. B.; Dunham, E. J.; Spencer, J. R.; Stansberry, J. A.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_19990018501'); toggleEditAbsImage('author_19990018501_show'); toggleEditAbsImage('author_19990018501_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_19990018501_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_19990018501_hide"></p> <p>1998-01-01</p> <p>Triton, Neptune's largest moon, has been predicted to undergo significant <span class="hlt">seasonal</span> changes that would reveal themselves as changes in its mean frost temperature. But whether this temperature should at the present time be increasing, decreasing or constant depends on a number of parameters (such as the thermal properties of the surface, and frost migration patterns) that are unknown. Here we report observations of a recent stellar occultation by Triton which, when combined with earlier results, show that Triton has undergone a period of global <span class="hlt">warming</span> since 1989. Our most conservative estimates of the rate of temperature and surface-pressure increase during this period imply that the atmosphere is doubling in bulk every 10 years, significantly faster than predicted by any published frost model for Triton. Our result suggests that permanent polar caps on Triton play a c dominant role in regulating <span class="hlt">seasonal</span> atmospheric changes. Similar processes should also be active on Pluto.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22904126','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22904126"><span>Designing a <span class="hlt">warm</span>-up protocol for elite bob-skeleton athletes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cook, Christian; Holdcroft, Danny; Drawer, Scott; Kilduff, Liam P</p> <p>2013-03-01</p> <p>To investigate how different <span class="hlt">warm</span>-ups influenced subsequent sled-pull sprint performance in Olympic-level bob-skeleton athletes as part of their preparation for the 2010 Winter Olympics. Three female and 3 male athletes performed 5 different randomized <span class="hlt">warm</span>-ups of differing intensities, durations, and timing relative to subsequent testing, each 2 days apart, all repeated twice. After <span class="hlt">warm</span>-ups, testing on a sled-pull sprint over 20 m, 3 repeats 3 min apart, took place. Performance testing showed improvement (P < .001, ES > 1.2) with both increasing intensity of <span class="hlt">warm</span>-up and closeness of completion to testing, with 20-m sled sprinting being 0.1-0.25 s faster in higher-intensity protocols performed near testing In addition, supplementing the <span class="hlt">warm</span>-ups by wearing of a light survival coat resulted in further performance improvement (P = .000, ES 1.8). Changing timing and intensity of <span class="hlt">warm</span>-up and using an ancillary passive heat-retention device improved sprint performance in Olympic-level bob-skeleton athletes. Subsequent adoption of these on the competitive circuit was associated with a <span class="hlt">seasonal</span> improvement in push times and was ultimately implemented in the 2010 Winter Olympics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMPP31F..07G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMPP31F..07G"><span>Disentangling <span class="hlt">Seasonality</span> and Mean Annual Precipitation in the Indo-Pacific <span class="hlt">Warm</span> Pool: Insights from Coupled Plant Wax C and H Isotope Measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Galy, V.; Oppo, D.; Dubois, N.; Arbuszewski, J. A.; Mohtadi, M.; Schefuss, E.; Rosenthal, Y.; Linsley, B. K.</p> <p>2016-12-01</p> <p>There is ample evidence suggesting that rainfall distribution across the Indo-Pacific <span class="hlt">Warm</span> Pool (IPWP) - a key component of the global climate system - has substantially varied over the last deglaciation. Yet, the precise nature of these hydroclimate changes remains to be elucidated. In particular, the relative importance of variations in precipitation <span class="hlt">seasonality</span> versus annual precipitation amount is essentially unknown. Here we use a set of surface sediments from the IPWP covering a wide range of modern hydroclimate conditions to evaluate how plant wax stable isotope composition records rainfall distribution in the area. We focus on long chain fatty acids, which are exclusively produced by vascular plants living on nearby land and delivered to the ocean by rivers. We relate the C (δ13C) and H (δD) isotope composition of long chain fatty acids preserved in surface sediments to modern precipitation distribution and stable isotope composition in their respective source area. We show that: 1) δ13C values reflect vegetation distribution (in particular the relative abundance of C3 and C4 plants) and are primarily recording precipitation <span class="hlt">seasonality</span> (Dubois et al., 2014) and, 2) once corrected for plant fractionation effects, δD values reflect the amount-weighted average stable isotope composition of precipitation and are primarily recording annual precipitation amounts. We propose that combining the C and H isotope composition of long chain fatty acids thus allows independent reconstructions of precipitation <span class="hlt">seasonality</span> and annual amounts in the IPWP. The practical implications for reconstructing past hydroclimate in the IPWP will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H43H1739H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H43H1739H"><span>Hydrological Responses of Chaobai River Basin under 1.5° and 2.0° Global <span class="hlt">Warming</span> Using Multi-GCMs and Multi-RCPs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hao, Y.; Ma, J.</p> <p>2017-12-01</p> <p>The global <span class="hlt">warming</span> of 1.5° and 2.0° proposed in Paris Agreement has became the iconic threshold of climate change impact research and discussion. In order to provide useful reference to the effective water resource management and planning for the capital city of China, this study aims to assessing the potential impact of 1.5° and 2.0° global <span class="hlt">warming</span> on river discharge in Chaobai River Basin(CRB) which is main water supply source of Beijing. A semi-distributed hydrological model SWAT was driven by climate projections from five General Circulation Models(GCMs) under three Representative Concentration Pathways (RCP4.5, RCP6.0 and RCP8.5) to simulate the future discharge in CRB under 1.5° and 2.0° global <span class="hlt">warming</span> respectively. On this basis, climate change impact on annual and <span class="hlt">monthly</span> discharge, <span class="hlt">seasonal</span> discharge distribution, extreme <span class="hlt">monthly</span> discharge in CRB were assessed and the uncertainty associated with GCMs and RCPs were analyzed quantitatively. The results indicate that the average annual discharge will increase slightly and more concentrate in midsummer and early autumn under 1.5° global <span class="hlt">warming</span>. When the global average temperature rise 2°, the annual discharge in CRB show an evident positive tendency with the magnitude increasing by approximate 30% and the extreme <span class="hlt">monthly</span> runoff will significantly increase. However, the proportion of discharge in summer which is the peak water usage period will decline. It is obvious that the increment of 0.5° will lead to more flood events and bring great challenge to water resource management. There is a certain uncertainty in the projection of temperature, precipitation and discharge, by contrast, uncertainty of discharge projection is far greater than that of other two meteorological elements. Compared with RCPs, GCMs are proved to be the main factor which are responsible for the impact uncertainty in CRB under two global <span class="hlt">warming</span> horizons. The uncertainty will be larger as the <span class="hlt">warming</span> magnitude increase. In a word</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4738287','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4738287"><span>Global <span class="hlt">Warming</span> Attenuates the Tropical Atlantic-Pacific Teleconnection</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Jia, Fan; Wu, Lixin; Gan, Bolan; Cai, Wenju</p> <p>2016-01-01</p> <p>Changes in global sea surface temperature (SST) since the end of last century display a pattern of widespread <span class="hlt">warming</span> intercepted by cooling in the eastern equatorial Pacific and western coasts of the American continent. Studies have suggested that the cooling in the eastern equatorial Pacific may be partly induced by <span class="hlt">warming</span> in the North Atlantic. However, it remains unknown how stable this inter-tropical teleconnection will be under global <span class="hlt">warming</span>. Here we show that the inter-tropical teleconnection from the tropical Atlantic to Pacific weakens substantially as the CO2 concentration increases. This reduced impact is related to the El Niño-like <span class="hlt">warming</span> of the tropical Pacific mean state, which leads to limited <span class="hlt">seasonal</span> migration of the Pacific inter-tropical convergence zone (ITCZ) and weakened ocean heat transport. A fast decay of the tropical Atlantic SST anomalies in a warmer climate also contributes to the weakened teleconnection. Our study suggests that as greenhouse <span class="hlt">warming</span> continues, the trend in the tropical Pacific as well as the development of ENSO will be less frequently interrupted by the Atlantic because of this attenuation. The weakened teleconnection is also supported by CMIP5 models, although only a few of these models can capture this inter-tropical teleconnection. PMID:26838053</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26838053','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26838053"><span>Global <span class="hlt">Warming</span> Attenuates the Tropical Atlantic-Pacific Teleconnection.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jia, Fan; Wu, Lixin; Gan, Bolan; Cai, Wenju</p> <p>2016-02-03</p> <p>Changes in global sea surface temperature (SST) since the end of last century display a pattern of widespread <span class="hlt">warming</span> intercepted by cooling in the eastern equatorial Pacific and western coasts of the American continent. Studies have suggested that the cooling in the eastern equatorial Pacific may be partly induced by <span class="hlt">warming</span> in the North Atlantic. However, it remains unknown how stable this inter-tropical teleconnection will be under global <span class="hlt">warming</span>. Here we show that the inter-tropical teleconnection from the tropical Atlantic to Pacific weakens substantially as the CO2 concentration increases. This reduced impact is related to the El Niño-like <span class="hlt">warming</span> of the tropical Pacific mean state, which leads to limited <span class="hlt">seasonal</span> migration of the Pacific inter-tropical convergence zone (ITCZ) and weakened ocean heat transport. A fast decay of the tropical Atlantic SST anomalies in a warmer climate also contributes to the weakened teleconnection. Our study suggests that as greenhouse <span class="hlt">warming</span> continues, the trend in the tropical Pacific as well as the development of ENSO will be less frequently interrupted by the Atlantic because of this attenuation. The weakened teleconnection is also supported by CMIP5 models, although only a few of these models can capture this inter-tropical teleconnection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22538105','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22538105"><span>[Incidence of proximal femur fractures in relation to <span class="hlt">seasons</span> of the year and weather].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Burget, F; Pleva, L; Kudrna, K; Kudrnová, Z</p> <p>2012-01-01</p> <p>The opinion that proximal femur fractures occur mainly in the winter <span class="hlt">season</span> and are related to slippery surfaces prevails in both the lay and medical communities. The elucidation of this relationship would lead to a better understanding of the aetiology of these fractures and may help to prevent them in the elderly population. In a retrospective study conducted at two departments, the occurrence of proximal femur fractures in patients 60+ years old in relation to weather conditions (air temperature and its humidity, atmospheric pressure, rain and mist) between January 1, 2001 and December 31, 2005 was investigated. Patients with high-energy or pathological fractures were excluded. The results were evaluated by Statistika software. A total of 1720 patients were studied, of whom 1313 were women and 407 were men. The numbers of fractures did not differ significantly among either the <span class="hlt">seasons</span> or <span class="hlt">months</span> of the year. No correlation was found between the number of fractures and each of the weather characteristics (air temperature and its humidity, atmospheric pressure, wind speed and visibility). It is widely believed that hip fractures are connected with winter <span class="hlt">months</span> and temperatures below zero. This is supported by several facts related to winter characteristics, such as slippery icy pavements, clumsiness due to <span class="hlt">warm</span> bulky clothes, bodies affected by cold and thus predisposed to a fall and poorer visibility on shorter winter days. The effect of <span class="hlt">seasonal</span> variation on hip fracture incidence has been investigated in 10 studies of which only one has taken the influence of daily temperature into consideration. All studies were conduced in the countries north of 40° latitude, i.e., in climatic conditions similar to our country, with temperatures falling below zero and ice-glazed pavements in winter <span class="hlt">months</span>. Of them, six have found no relation between proximal femur fractures and weather conditions, two have reported an increased incidence of these fractures in winter <span class="hlt">months</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1358195','SCIGOV-DOEDE'); return false;" href="https://www.osti.gov/servlets/purl/1358195"><span>NGEE Arctic Zero Power <span class="hlt">Warming</span> PhenoCamera Images, Barrow, Alaska, 2016</span></a></p> <p><a target="_blank" href="http://www.osti.gov/dataexplorer">DOE Data Explorer</a></p> <p>Shawn Serbin; Andrew McMahon; Keith Lewin; Kim Ely; Alistair Rogers</p> <p>2016-11-14</p> <p>StarDot NetCam SC pheno camera images collected from the top of the Barrow, BEO Sled Shed. The camera was installed to monitor the BNL TEST group's prototype ZPW (Zero Power <span class="hlt">Warming</span>) chambers during the growing <span class="hlt">season</span> of 2016 (including early spring and late fall). Images were uploaded to the BNL FTP server every 10 minutes and renamed with the date and time of the image. See associated data "Zero Power <span class="hlt">Warming</span> (ZPW) Chamber Prototype Measurements, Barrow, Alaska, 2016" http://dx.doi.org/10.5440/1343066.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23903564','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23903564"><span>The role of phytophysiognomies and <span class="hlt">seasonality</span> on the structure of ground-dwelling anuran (Amphibia) in the Pampa biome, Southern Brazil.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Maragno, Franciéle P; Santos, Tiago G; Cechin, Sonia Z</p> <p>2013-09-01</p> <p>Considering that habitat use by amphibians is related both with climate and environmental features, we tested the hypothesis that anuran assemblages found in different phytophysiognomies and in different <span class="hlt">seasons</span> vary in structure. Additionally, we searched for species which can be indicators of habitat and <span class="hlt">seasons</span>. The study was conducted in the Pampa biome, southern Brazil. Sampling was done through pitfall traps placed in three phytophysiognomies: grassland, ecotone grassland/forest; and forest. The <span class="hlt">seasonality</span> factor was created by grouping <span class="hlt">months</span> in warn and cold <span class="hlt">seasons</span>. Sixteen species were found and the assemblages were influenced both by phytophysiognomies and climatic <span class="hlt">seasonality</span>. In a paired comparison, the three phytophysiognomies differed in structure of assemblage from each other. Physalaemus henselii, P. riograndensis, Pseudopaludicola falcipes and Pseudis minuta were indicators of ecotone. Leptodactylus gracilis and Physalaemus biligonigerus were indicators of grassland. None species was indicator of forest. Most of the species were indicators of <span class="hlt">warm</span> <span class="hlt">season</span>: Elachistocleis bicolor, Leptodactylus fuscus, L. gracilis, L. latinasus, L. latrans, L. mystacinus, Physalaemus biligonigerus, P. cuvieri and Pseudis minuta. None species was indicator of cold <span class="hlt">season</span>. We found that even for species of open areas, as Pampa, heterogeneous phytophysiognomies are important for maintaining abundance and constancy of populations of anuran.</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" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3281109','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3281109"><span>The Effects of <span class="hlt">Warming</span>-Shifted Plant Phenology on Ecosystem Carbon Exchange Are Regulated by Precipitation in a Semi-Arid Grassland</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Xia, Jianyang; Wan, Shiqiang</p> <p>2012-01-01</p> <p>Background The longer growing <span class="hlt">season</span> under climate <span class="hlt">warming</span> has served as a crucial mechanism for the enhancement of terrestrial carbon (C) sink over the past decades. A better understanding of this mechanism is critical for projection of changes in C cycling of terrestrial ecosystems. Methodology/Principal Findings A 4-year field experiment with day and night <span class="hlt">warming</span> was conducted to examine the responses of plant phenology and their influences on plant coverage and ecosystem C cycling in a temperate steppe in northern China. Greater phenological responses were observed under night than day <span class="hlt">warming</span>. Both day and night <span class="hlt">warming</span> prolonged the growing <span class="hlt">season</span> by advancing phenology of early-blooming species but without changing that of late-blooming species. However, no <span class="hlt">warming</span> response of vegetation coverage was found for any of the eight species. The variances in species-level coverage and ecosystem C fluxes under different treatments were positively dependent upon the accumulated precipitation within phenological duration but not the length of phenological duration. Conclusions/Significance These plants' phenology is more sensitive to night than day <span class="hlt">warming</span>, and the <span class="hlt">warming</span> effects on ecosystem C exchange via shifting plant phenology could be mediated by precipitation patterns in semi-arid grasslands. PMID:22359660</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMGC51A0731K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMGC51A0731K"><span>Downscaling of snow depth and river discharge in Japan by the Pseudo-Global-<span class="hlt">Warming</span> Method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kimura, F.; Ma, X.; Hara, M.; Advanced Atmosphere-Ocean-Land Modeling Program</p> <p>2010-12-01</p> <p>Although a heavy snowfall often brings disaster, snow cover is one of the major water resources in Japan. Even during the winter, the <span class="hlt">monthly</span> mean of the surface air temperature often exceeds 0 deg. in large parts of the heavy snow areas along the Sea of Japan. Thus, snow cover may be seriously reduced in these areas as a result of global <span class="hlt">warming</span>, which is caused by an increase in greenhouse gases. This study estimates the impact of global <span class="hlt">warming</span> on the snow depth in Japan during early winter. Some dynamical downscaling experiments are conducted by the Pseudo-Global-<span class="hlt">Warming</span> method for the future projection of snow cover. By the hindcast runs, precipitation, snow depth, and surface air temperature show good agreement with the AMeDAS station data observed in a High-Snow-Cover (HSC) year and a Low-Snow-Cover (LSC) yea. Pseudo-Global-<span class="hlt">Warming</span> runs for these years indicate that the decreasing ratios of the snow water are more significant in the areas whose altitude is less than 1500 m. The increase of the air temperature is one of the major factors for the decrease in snow water, since the present mean air temperature in most of these areas is near 0 deg. even in winter. On the other hand, the change in the aerial-mean precipitation due to global <span class="hlt">warming</span> is less than 15% in both years. To evaluate the impact of the reduction of snow cover to water resource, a hydrological simulation is also made for the Agano River basin, which locates in Niigata and Fukushima Prefectures. The Agano River drains into the Sea of Japan and is the second largest river in Japan with annual discharge of about 12.9 billion m3. A hind cast experiment is carried out for the two decades from 1980 to 1999. The average correlation coefficient of 0.79 for the <span class="hlt">monthly</span> mean discharge in the winter <span class="hlt">season</span> indicates that the interannual variation of the river discharge could be reproduced and that the method is useful for climate change study. Then the hydrological response to the future global <span class="hlt">warming</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1360515','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1360515"><span>Plant community responses to experimental <span class="hlt">warming</span> across the tundra biome</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Walker, Marilyn D.; Wahren, C. Henrik; Hollister, Robert D.; Henry, Greg H. R.; Ahlquist, Lorraine E.; Alatalo, Juha M.; Bret-Harte, M. Syndonia; Calef, Monika P.; Callaghan, Terry V.; Carroll, Amy B.; Epstein, Howard E.; Jónsdóttir, Ingibjörg S.; Klein, Julia A.; Magnússon, Borgþór; Molau, Ulf; Oberbauer, Steven F.; Rewa, Steven P.; Robinson, Clare H.; Shaver, Gaius R.; Suding, Katharine N.; Thompson, Catharine C.; Tolvanen, Anne; Totland, Ørjan; Turner, P. Lee; Tweedie, Craig E.; Webber, Patrick J.; Wookey, Philip A.</p> <p>2006-01-01</p> <p>Recent observations of changes in some tundra ecosystems appear to be responses to a <span class="hlt">warming</span> climate. Several experimental studies have shown that tundra plants and ecosystems can respond strongly to environmental change, including <span class="hlt">warming</span>; however, most studies were limited to a single location and were of short duration and based on a variety of experimental designs. In addition, comparisons among studies are difficult because a variety of techniques have been used to achieve experimental <span class="hlt">warming</span> and different measurements have been used to assess responses. We used metaanalysis on plant community measurements from standardized <span class="hlt">warming</span> experiments at 11 locations across the tundra biome involved in the International Tundra Experiment. The passive <span class="hlt">warming</span> treatment increased plant-level air temperature by 1-3°C, which is in the range of predicted and observed <span class="hlt">warming</span> for tundra regions. Responses were rapid and detected in whole plant communities after only two growing <span class="hlt">seasons</span>. Overall, <span class="hlt">warming</span> increased height and cover of deciduous shrubs and graminoids, decreased cover of mosses and lichens, and decreased species diversity and evenness. These results predict that <span class="hlt">warming</span> will cause a decline in biodiversity across a wide variety of tundra, at least in the short term. They also provide rigorous experimental evidence that recently observed increases in shrub cover in many tundra regions are in response to climate <span class="hlt">warming</span>. These changes have important implications for processes and interactions within tundra ecosystems and between tundra and the atmosphere. PMID:16428292</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GSL.....3...20D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GSL.....3...20D"><span>The Indo-Pacific <span class="hlt">Warm</span> Pool: critical to world oceanography and world climate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>De Deckker, Patrick</p> <p>2016-12-01</p> <p>The Indo-Pacific <span class="hlt">Warm</span> Pool holds a unique place on the globe. It is a large area [>30 × 106 km2] that is characterised by permanent surface temperature >28 °C and is therefore called the `heat engine' of the globe. High convective clouds which can reach altitudes up to 15 km generate much latent heat in the process of convection and this area is therefore called the `steam engine' of the world. <span class="hlt">Seasonal</span> and contrasting monsoonal activity over the region is the cause for a broad <span class="hlt">seasonal</span> change of surface salinities, and since the area lies along the path of the Great Ocean Conveyor Belt, it is coined the `dilution' basin due to the high incidence of tropical rain and, away from the equator, tropical cyclones contribute to a significant drop in sea water salinity. Discussion about what may happen in the future of the <span class="hlt">Warm</span> Pool under global <span class="hlt">warming</span> is presented together with a description of the <span class="hlt">Warm</span> Pool during the past, such as the Last Glacial Maximum when sea levels had dropped by ~125 m. A call for urgent monitoring of the IPWP area is justified on the grounds of the significance of this area for global oceanographic and climatological processes, but also because of the concerned threats to human population living there.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ERL....13b4029B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ERL....13b4029B"><span>Does the projected pathway to global <span class="hlt">warming</span> targets matter?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bärring, Lars; Strandberg, Gustav</p> <p>2018-02-01</p> <p>Since the ‘Paris agreement’ in 2015 there has been much focus on what a +1.5 °C or +2 °C warmer world would look like. Since the focus lies on policy relevant global <span class="hlt">warming</span> targets, or specific <span class="hlt">warming</span> levels (SWLs), rather than a specific point in time, projections are pooled together to form SWL ensembles based on the target temperature rather than emission scenario. This study uses an ensemble of CMIP5 global model projections to analyse how well SWL ensembles represent the stabilized climate of global <span class="hlt">warming</span> targets. The results show that the SWL ensembles exhibit significant trends that reflect the transient nature of the RCP scenarios. These trends have clear effect on the timing and clustering of <span class="hlt">monthly</span> cold and hot extremes, even though the effect on the temperature of the extreme <span class="hlt">months</span> is less visible. In many regions there is a link between choice of RCP scenario used in the SWL ensemble and climate change signal in the highest <span class="hlt">monthly</span> temperatures. In other regions there is no such clear-cut link. From this we conclude that comprehensive analyses of what prospects the different global <span class="hlt">warming</span> targets bring about will require stabilization scenarios. Awaiting such targeted scenarios we suggest that prudent use of SWL scenarios, taking their characteristics and limitations into account, may serve as reasonable proxies in many situations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.B43C0310K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.B43C0310K"><span><span class="hlt">Seasonality</span> of primary and secondary production in an Arctic river</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kendrick, M.; Huryn, A.; Deegan, L.</p> <p>2011-12-01</p> <p>Rivers and streams that freeze solid for 8-9 <span class="hlt">months</span> each year provide excellent examples of the extreme <span class="hlt">seasonality</span> of arctic habitats. The communities of organisms inhabiting these rivers must complete growth and development during summer, resulting in a rapid ramp-up and down of production over the short ice-free period. The effects of recent shifts in the timing of the spring thaw and autumn freeze-up on the duration and pattern of the period of active production are poorly understood. We are currently investigating: 1) the response of the biotic community of the Kuparuk River (Arctic Alaska) to shifts in the <span class="hlt">seasonality</span> of the ice-free period, and 2) the community response to increases in phosphorous (P) supply anticipated as the volume of the permafrost active-layer increases in response to climate <span class="hlt">warming</span>. Here algal production supports a 2-tier web of consumers. We tracked primary and secondary production from the spring thaw through mid-August in a reference reach and one receiving low-level P fertilization. Gross primary production/community respiration (GPP/R) ratios for both reaches were increasing through mid-July, with higher GPP/R in response to the P addition. Understanding the degree of synchrony between primary and secondary production in this Arctic river system will enhance further understanding of how shifts in <span class="hlt">seasonality</span> affect trophic dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AIPC.1905e0018F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AIPC.1905e0018F"><span>Prediction of South China sea level using <span class="hlt">seasonal</span> ARIMA models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fernandez, Flerida Regine; Po, Rodolfo; Montero, Neil; Addawe, Rizavel</p> <p>2017-11-01</p> <p>Accelerating sea level rise is an indicator of global <span class="hlt">warming</span> and poses a threat to low-lying places and coastal countries. This study aims to fit a <span class="hlt">Seasonal</span> Autoregressive Integrated Moving Average (SARIMA) model to the time series obtained from the TOPEX and Jason series of satellite radar altimetries of the South China Sea from the year 2008 to 2015. With altimetric measurements taken in a 10-day repeat cycle, <span class="hlt">monthly</span> averages of the satellite altimetry measurements were taken to compose the data set used in the study. SARIMA models were then tried and fitted to the time series in order to find the best-fit model. Results show that the SARIMA(1,0,0)(0,1,1)12 model best fits the time series and was used to forecast the values for January 2016 to December 2016. The 12-<span class="hlt">month</span> forecast using SARIMA(1,0,0)(0,1,1)12 shows that the sea level gradually increases from January to September 2016, and decreases until December 2016.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27647059','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27647059"><span><span class="hlt">Warm</span> Handoff Versus Fax Referral for Linking Hospitalized Smokers to Quitlines.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Richter, Kimber P; Faseru, Babalola; Shireman, Theresa I; Mussulman, Laura M; Nazir, Niaman; Bush, Terry; Scheuermann, Taneisha S; Preacher, Kristopher J; Carlini, Beatriz H; Magnusson, Brooke; Ellerbeck, Edward F; Cramer, Carol; Cook, David J; Martell, Mary J</p> <p>2016-10-01</p> <p>Few hospitals treat patients' tobacco dependence. To be effective, hospital-initiated cessation interventions must provide at least 1 <span class="hlt">month</span> of supportive contact post-discharge. Individually randomized clinical trial. Recruitment commenced July 2011; analyses were conducted October 2014-June 2015. The study was conducted in two large Midwestern hospitals. Participants included smokers who were aged ≥18 years, planned to stay quit after discharge, and spoke English or Spanish. Hospital-based cessation counselors delivered the intervention. For patients randomized to <span class="hlt">warm</span> handoff, staff immediately called the quitline from the bedside and handed the phone to participants for enrollment and counseling. Participants randomized to fax were referred on the day of hospital discharge. Outcomes at 6 <span class="hlt">months</span> included quitline enrollment/adherence, medication use, biochemically verified cessation, and cost effectiveness. Significantly more <span class="hlt">warm</span> handoff than fax participants enrolled in quitline (99.6% vs 59.6%; relative risk, 1.67; 95% CI=1.65, 1.68). One in four (25.4% <span class="hlt">warm</span> handoff, 25.3% fax) were verified to be abstinent at 6-<span class="hlt">month</span> follow-up; this did not differ significantly between groups (relative risk, 1.02; 95% CI=0.82, 1.24). Cessation medication use in the hospital and receipt of a prescription for medication at discharge did not differ between groups; however, significantly more fax participants reported using cessation medication post-discharge (32% vs 25%, p=0.01). The average incremental cost-effectiveness ratio of enrolling participants into <span class="hlt">warm</span> handoff was $0.14. Hospital-borne costs were significantly lower in <span class="hlt">warm</span> handoff than in fax ($5.77 vs $9.41, p<0.001). One in four inpatient smokers referred to quitline by either method were abstinent at 6 <span class="hlt">months</span> post-discharge. Among motivated smokers, fax referral and <span class="hlt">warm</span> handoff are efficient and comparatively effective ways to link smokers with evidence-based care. For hospitals, <span class="hlt">warm</span> handoff is a less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28605857','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28605857"><span>Effects of <span class="hlt">warming</span> and nitrogen fertilization on GHG flux in an alpine swamp meadow of a permafrost region.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Xiaopeng; Wang, Genxu; Zhang, Tao; Mao, Tianxu; Wei, Da; Song, Chunlin; Hu, Zhaoyong; Huang, Kewei</p> <p>2017-12-01</p> <p>Uncertainties in the <span class="hlt">seasonal</span> changes of greenhouse gases (GHG) fluxes in wetlands limit our accurate understanding of the responses of permafrost ecosystems to future <span class="hlt">warming</span> and increased nitrogen (N) deposition. Therefore, in an alpine swamp meadow in the hinterland of the Qinghai-Tibet Plateau, a simulated <span class="hlt">warming</span> with N fertilization experiment was conducted to investigate the key GHG fluxes (ecosystem respiration [Re], CH 4 and N 2 O) in the early (EG), mid (MG) and late (LG) growing <span class="hlt">seasons</span>. Results showed that <span class="hlt">warming</span> (6.2 °C) increased the average <span class="hlt">seasonal</span> Re by 30.9% and transformed the alpine swamp meadow from a N 2 O sink to a source, whereas CH 4 flux was not significantly affected. N fertilization (4 g N m -2 a -1 ) alone had no significant effect on the fluxes of GHGs. The interaction of <span class="hlt">warming</span> and N fertilization increased CH 4 uptake by 69.6% and N 2 O emissions by 26.2% compared with <span class="hlt">warming</span>, whereas the Re was not significantly affected. During the EG, although the soil temperature sensitivity of the Re was the highest, the effect of <span class="hlt">warming</span> on the Re was the weakest. The primary driving factor for Re was soil surface temperature, whereas soil moisture controlled CH 4 flux, and the N 2 O flux was primarily affected by rain events. The results indicated: (i) increasing N deposition has both positive and negative feedbacks on GHG fluxes in response to climate <span class="hlt">warming</span>; (ii) during soil thawing process at active layer, low temperature of deep frozen soils have a negative contribution to Re in alpine ecosystems; and (iii) although these alpine wetland ecosystems are buffers against increased temperature, their feedbacks on climate change cannot be ignored because of the large soil organic carbon pool and high temperature sensitivity of the Re. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMGC32A..03W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMGC32A..03W"><span>The Changing <span class="hlt">Seasonality</span> of Tundra Nutrient Cycling: Implications for Arctic Ecosystem Function</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weintraub, M. N.; Steltzer, H.; Sullivan, P.; Schimel, J.; Wallenstein, M. D.; Darrouzet-Nardi, A.; Segal, A. D.</p> <p>2011-12-01</p> <p>Arctic soils contain large stores of carbon (C) and may act as a significant CO2 source with <span class="hlt">warming</span>. However, the key to understanding tundra soil processes is nitrogen (N), as both plant growth and decomposition are N limited. However, current models of tundra ecosystems assume that while N limits plant growth, C limits decomposition. In addition, N availability is strongly <span class="hlt">seasonal</span> with relatively high concentrations early in the growing <span class="hlt">season</span> followed by a pronounced crash. We need to understand the controls on this <span class="hlt">seasonality</span> to predict responses to climate change, but there are multiple questions that need answers: 1) What causes the <span class="hlt">seasonality</span> in N? 2) Does microbial activity switch <span class="hlt">seasonally</span> between C and N limitation? 3) How will a lengthening of the growing <span class="hlt">season</span> alter overall ecosystem C and N dynamics, as a result of differential extension of the periods before and after the nutrient crash? We hypothesized that microbial activity is C limited early in the growing <span class="hlt">season</span>, when N availability is higher and root exudate C is unavailable, and that microbial activity becomes N limited in response to plant N uptake and immobilization stimulated by root C. To address these questions we are conducting an accelerated snow-melt X <span class="hlt">warming</span> field experiment in an Alaskan moist acidic arctic tundra community, and following plant and soil dynamics. Changes in the timing of C and N interactions in the different treatments will enable us to develop an enhanced mechanistic understanding of why the nutrient crash occurs and what the implications are for a lengthening of the arctic growing <span class="hlt">season</span>. In 2010 we successfully accelerated snowmelt by 4 days. Both earlier snowmelt and <span class="hlt">warming</span> accelerated early <span class="hlt">season</span> plant life history events, with a few exceptions. However, responses to the combined treatment could not always be predicted from single factor effects. End of <span class="hlt">season</span> life history events occurred later in response to the treatments, again with a few exceptions</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1237098','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1237098"><span>Changes in Intense Precipitation Events in West Africa and the central U.S. under Global <span class="hlt">Warming</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Cook, Kerry H.; Vizy, Edward</p> <p></p> <p>The purpose of the proposed project is to improve our understanding of the physical processes and large-scale connectivity of changes in intense precipitation events (high rainfall rates) under global <span class="hlt">warming</span> in West Africa and the central U.S., including relationships with low-frequency modes of variability. This is in response to the requested subject area #2 “simulation of climate extremes under a changing climate … to better quantify the frequency, duration, and intensity of extreme events under climate change and elucidate the role of low frequency climate variability in modulating extremes.” We will use a regional climate model and emphasize an understandingmore » of the physical processes that lead to an intensification of rainfall. The project objectives are as follows: 1. Understand the processes responsible for simulated changes in <span class="hlt">warm-season</span> rainfall intensity and frequency over West Africa and the Central U.S. associated with greenhouse gas-induced global <span class="hlt">warming</span> 2. Understand the relationship between changes in <span class="hlt">warm-season</span> rainfall intensity and frequency, which generally occur on regional space scales, and the larger-scale global <span class="hlt">warming</span> signal by considering modifications of low-frequency modes of variability. 3. Relate changes simulated on regional space scales to global-scale theories of how and why atmospheric moisture levels and rainfall should change as climate <span class="hlt">warms</span>.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70027795','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70027795"><span>Role of land-surface changes in arctic summer <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Chapin, F. S.; Sturm, M.; Serreze, Mark C.; McFadden, J.P.; Key, J.R.; Lloyd, A.H.; McGuire, A.D.; Rupp, T.S.; Lynch, A.H.; Schimel, Joshua P.; Beringer, J.; Chapman, W.L.; Epstein, H.E.; Euskirchen, E.S.; Hinzman, L.D.; Jia, G.; Ping, C.-L.; Tape, K.D.; Thompson, C.D.C.; Walker, D.A.; Welker, J.M.</p> <p>2005-01-01</p> <p>A major challenge in predicting Earth's future climate state is to understand feedbacks that alter greenhouse-gas forcing. Here we synthesize field data from arctic Alaska, showing that terrestrial changes in summer albedo contribute substantially to recent high-latitude <span class="hlt">warming</span> trends. Pronounced terrestrial summer <span class="hlt">warming</span> in arctic Alaska correlates with a lengthening of the snow-free <span class="hlt">season</span> that has increased atmospheric heating locally by about 3 watts per square meter per decade (similar in magnitude to the regional heating expected over multiple decades from a doubling of atmospheric CO2). The continuation of current trends in shrub and tree expansion could further amplify this atmospheric heating by two to seven times.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26090931','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26090931"><span>Changes in Extremely Hot Summers over the Global Land Area under Various <span class="hlt">Warming</span> Targets.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Lei; Huang, Jianbin; Luo, Yong; Yao, Yao; Zhao, Zongci</p> <p>2015-01-01</p> <p>Summer temperature extremes over the global land area were investigated by comparing 26 models of the fifth phase of the Coupled Model Intercomparison Project (CMIP5) with observations from the Goddard Institute for Space Studies (GISS) and the Climate Research Unit (CRU). <span class="hlt">Monthly</span> data of the observations and models were averaged for each <span class="hlt">season</span>, and statistics were calculated for individual models before averaging them to obtain ensemble means. The summers with temperature anomalies (relative to 1951-1980) exceeding 3σ (σ is based on the local internal variability) are defined as "extremely hot". The models well reproduced the statistical characteristics evolution, and partly captured the spatial distributions of historical summer temperature extremes. If the global mean temperature increases 2°C relative to the pre-industrial level, "extremely hot" summers are projected to occur over nearly 40% of the land area (multi-model ensemble mean projection). Summers that exceed 5σ <span class="hlt">warming</span> are projected to occur over approximately 10% of the global land area, which were rarely observed during the reference period. Scenarios reaching <span class="hlt">warming</span> levels of 3°C to 5°C were also analyzed. After exceeding the 5°C <span class="hlt">warming</span> target, "extremely hot" summers are projected to occur throughout the entire global land area, and summers that exceed 5σ <span class="hlt">warming</span> would become common over 70% of the land area. In addition, the areas affected by "extremely hot" summers are expected to rapidly expand by more than 25%/°C as the global mean temperature increases by up to 3°C before slowing to less than 16%/°C as the temperature continues to increase by more than 3°C. The area that experiences summers with <span class="hlt">warming</span> of 5σ or more above the <span class="hlt">warming</span> target of 2°C is likely to maintain rapid expansion of greater than 17%/°C. To reduce the impacts and damage from severely hot summers, the global mean temperature increase should remain low.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4474600','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4474600"><span>Changes in Extremely Hot Summers over the Global Land Area under Various <span class="hlt">Warming</span> Targets</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Lei; Huang, Jianbin; Luo, Yong; Yao, Yao; Zhao, Zongci</p> <p>2015-01-01</p> <p>Summer temperature extremes over the global land area were investigated by comparing 26 models of the fifth phase of the Coupled Model Intercomparison Project (CMIP5) with observations from the Goddard Institute for Space Studies (GISS) and the Climate Research Unit (CRU). <span class="hlt">Monthly</span> data of the observations and models were averaged for each <span class="hlt">season</span>, and statistics were calculated for individual models before averaging them to obtain ensemble means. The summers with temperature anomalies (relative to 1951–1980) exceeding 3σ (σ is based on the local internal variability) are defined as “extremely hot”. The models well reproduced the statistical characteristics evolution, and partly captured the spatial distributions of historical summer temperature extremes. If the global mean temperature increases 2°C relative to the pre-industrial level, “extremely hot” summers are projected to occur over nearly 40% of the land area (multi-model ensemble mean projection). Summers that exceed 5σ <span class="hlt">warming</span> are projected to occur over approximately 10% of the global land area, which were rarely observed during the reference period. Scenarios reaching <span class="hlt">warming</span> levels of 3°C to 5°C were also analyzed. After exceeding the 5°C <span class="hlt">warming</span> target, “extremely hot” summers are projected to occur throughout the entire global land area, and summers that exceed 5σ <span class="hlt">warming</span> would become common over 70% of the land area. In addition, the areas affected by “extremely hot” summers are expected to rapidly expand by more than 25%/°C as the global mean temperature increases by up to 3°C before slowing to less than 16%/°C as the temperature continues to increase by more than 3°C. The area that experiences summers with <span class="hlt">warming</span> of 5σ or more above the <span class="hlt">warming</span> target of 2°C is likely to maintain rapid expansion of greater than 17%/°C. To reduce the impacts and damage from severely hot summers, the global mean temperature increase should remain low. PMID:26090931</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29691388','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29691388"><span><span class="hlt">Warm</span> summers during the Younger Dryas cold reversal.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schenk, Frederik; Väliranta, Minna; Muschitiello, Francesco; Tarasov, Lev; Heikkilä, Maija; Björck, Svante; Brandefelt, Jenny; Johansson, Arne V; Näslund, Jens-Ove; Wohlfarth, Barbara</p> <p>2018-04-24</p> <p>The Younger Dryas (YD) cold reversal interrupts the <span class="hlt">warming</span> climate of the deglaciation with global climatic impacts. The sudden cooling is typically linked to an abrupt slowdown of the Atlantic Meridional Overturning Circulation (AMOC) in response to meltwater discharges from ice sheets. However, inconsistencies regarding the YD-response of European summer temperatures have cast doubt whether the concept provides a sufficient explanation. Here we present results from a high-resolution global climate simulation together with a new July temperature compilation based on plant indicator species and show that European summers remain <span class="hlt">warm</span> during the YD. Our climate simulation provides robust physical evidence that atmospheric blocking of cold westerly winds over Fennoscandia is a key mechanism counteracting the cooling impact of an AMOC-slowdown during summer. Despite the persistence of short <span class="hlt">warm</span> summers, the YD is dominated by a shift to a continental climate with extreme winter to spring cooling and short growing <span class="hlt">seasons</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC41B1010S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC41B1010S"><span>Change of ENSO characteristics in response to global <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, X.; Xia, Y.; Yan, Y.; Feng, W.; Huang, F.; Yang, X. Q.</p> <p>2017-12-01</p> <p>By using datasets of HadISST <span class="hlt">monthly</span> SST from 1895 to 2014 and 600-year simulations of two CESM model experiments with/without doubling of CO2 concentration, ENSO characteristics are compared pre- and post- global <span class="hlt">warming</span>. The main results are as follows. Due to global <span class="hlt">warming</span>, the maximum climatological SST <span class="hlt">warming</span> occurs in the tropical western Pacific (La Niña-like background <span class="hlt">warming</span>) and the tropical eastern Pacific (El Niño-like background <span class="hlt">warming</span>) for observations and model, respectively, resulting in opposite zonal SST gradient anomalies in the tropical Pacific. The La Niña-like background <span class="hlt">warming</span> induces intense surface divergence in the tropical central Pacific, which enhances the easterly trade winds in the tropical central-western Pacific and shifts the strongest ocean-atmosphere coupling westward, correspondingly. On the contrary, the El Niño-like background <span class="hlt">warming</span> causes westerly winds in the whole tropical Pacific and moves the strongest ocean-atmosphere coupling eastward. Under the La Niña-like background <span class="hlt">warming</span>, ENSO tends to develop and mature in the tropical central Pacific, because the background easterly wind anomaly weakens the ENSO-induced westerly wind anomaly in the tropical western Pacific, leading to the so-called "Central Pacific ENSO (CP ENSO)". However, the so-called "Eastern Pacific ENSO (EP ENSO)" is likely formed due to increased westerly wind anomaly by the El Niño-like background <span class="hlt">warming</span>. ENSO lifetime is significantly extended under both the El Niño-like and the La Niña-like background <span class="hlt">warmings</span>, and especially, it can be prolonged by up to 3 <span class="hlt">months</span> in the situation of El Niño-like background <span class="hlt">warming</span>. The prolonged El Nino lifetime mainly applies to extreme El Niño events, which is caused by earlier outbreak of the westerly wind bursts, shallower climatological thermocline depth and weaker "discharge" rate of the ENSO <span class="hlt">warm</span> signal in response to global <span class="hlt">warming</span>. Results from both observations and the model also show that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24167287','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24167287"><span>Microclimate moderates plant responses to macroclimate <span class="hlt">warming</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>De Frenne, Pieter; Rodríguez-Sánchez, Francisco; Coomes, David Anthony; Baeten, Lander; Verstraeten, Gorik; Vellend, Mark; Bernhardt-Römermann, Markus; Brown, Carissa D; Brunet, Jörg; Cornelis, Johnny; Decocq, Guillaume M; Dierschke, Hartmut; Eriksson, Ove; Gilliam, Frank S; Hédl, Radim; Heinken, Thilo; Hermy, Martin; Hommel, Patrick; Jenkins, Michael A; Kelly, Daniel L; Kirby, Keith J; Mitchell, Fraser J G; Naaf, Tobias; Newman, Miles; Peterken, George; Petrík, Petr; Schultz, Jan; Sonnier, Grégory; Van Calster, Hans; Waller, Donald M; Walther, Gian-Reto; White, Peter S; Woods, Kerry D; Wulf, Monika; Graae, Bente Jessen; Verheyen, Kris</p> <p>2013-11-12</p> <p>Recent global <span class="hlt">warming</span> is acting across marine, freshwater, and terrestrial ecosystems to favor species adapted to warmer conditions and/or reduce the abundance of cold-adapted organisms (i.e., "thermophilization" of communities). Lack of community responses to increased temperature, however, has also been reported for several taxa and regions, suggesting that "climatic lags" may be frequent. Here we show that microclimatic effects brought about by forest canopy closure can buffer biotic responses to macroclimate <span class="hlt">warming</span>, thus explaining an apparent climatic lag. Using data from 1,409 vegetation plots in European and North American temperate forests, each surveyed at least twice over an interval of 12-67 y, we document significant thermophilization of ground-layer plant communities. These changes reflect concurrent declines in species adapted to cooler conditions and increases in species adapted to warmer conditions. However, thermophilization, particularly the increase of <span class="hlt">warm</span>-adapted species, is attenuated in forests whose canopies have become denser, probably reflecting cooler growing-<span class="hlt">season</span> ground temperatures via increased shading. As standing stocks of trees have increased in many temperate forests in recent decades, local microclimatic effects may commonly be moderating the impacts of macroclimate <span class="hlt">warming</span> on forest understories. Conversely, increases in harvesting woody biomass--e.g., for bioenergy--may open forest canopies and accelerate thermophilization of temperate forest biodiversity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4319967','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4319967"><span>Microclimatic Performance of a Free-Air <span class="hlt">Warming</span> and CO2 Enrichment Experiment in Windy Wyoming, USA</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>LeCain, Daniel; Smith, David; Morgan, Jack; Kimball, Bruce A.; Pendall, Elise; Miglietta, Franco</p> <p>2015-01-01</p> <p>In order to plan for global changing climate experiments are being conducted in many countries, but few have monitored the effects of the climate change treatments (<span class="hlt">warming</span>, elevated CO2) on the experimental plot microclimate. During three years of an eight year study with year-round feedback-controlled infra-red heater <span class="hlt">warming</span> (1.5/3.0°C day/night) and growing <span class="hlt">season</span> free-air CO2 enrichment (600 ppm) in the mixed-grass prairie of Wyoming, USA, we monitored soil, leaf, canopy-air, above-canopy-air temperatures and relative humidity of control and treated experimental plots and evaluated ecologically important temperature differentials. Leaves were <span class="hlt">warmed</span> somewhat less than the target settings (1.1 & 1.5°C day/night) but soil was <span class="hlt">warmed</span> more creating an average that matched the target settings extremely well both during the day and night plus the summer and winter. The site typically has about 50% bare or litter covered soil, therefore soil heat transfer is more critical than in dense canopy ecosystems. The Wyoming site commonly has strong winds (5 ms-1 average) and significant daily and <span class="hlt">seasonal</span> temperature fluctuations (as much as 30°C daily) but the <span class="hlt">warming</span> system was nearly always able to maintain the set temperatures regardless of abiotic variation. The within canopy-air was only slightly <span class="hlt">warmed</span> and above canopy-air was not <span class="hlt">warmed</span> by the system, therefore convective <span class="hlt">warming</span> was minor. Elevated CO2 had no direct effect nor interaction with the <span class="hlt">warming</span> treatment on microclimate. Relative humidity within the plant canopy was only slightly reduced by <span class="hlt">warming</span>. Soil water content was reduced by <span class="hlt">warming</span> but increased by elevated CO2. This study demonstrates the importance of monitoring the microclimate in manipulative field global change experiments so that critical physiological and ecological conclusions can be determined. Highly variable energy demand fluctuations showed that passive IR heater <span class="hlt">warming</span> systems will not maintain desired <span class="hlt">warming</span> for much of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.7164E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.7164E"><span>GloFAS-<span class="hlt">Seasonal</span>: Operational <span class="hlt">Seasonal</span> Ensemble River Flow Forecasts at the Global Scale</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Emerton, Rebecca; Zsoter, Ervin; Smith, Paul; Salamon, Peter</p> <p>2017-04-01</p> <p><span class="hlt">Seasonal</span> hydrological forecasting has potential benefits for many sectors, including agriculture, water resources management and humanitarian aid. At present, no global scale <span class="hlt">seasonal</span> hydrological forecasting system exists operationally; although smaller scale systems have begun to emerge around the globe over the past decade, a system providing consistent global scale <span class="hlt">seasonal</span> forecasts would be of great benefit in regions where no other forecasting system exists, and to organisations operating at the global scale, such as disaster relief. We present here a new operational global ensemble <span class="hlt">seasonal</span> hydrological forecast, currently under development at ECMWF as part of the Global Flood Awareness System (GloFAS). The proposed system, which builds upon the current version of GloFAS, takes the long-range forecasts from the ECMWF System4 ensemble <span class="hlt">seasonal</span> forecast system (which incorporates the HTESSEL land surface scheme) and uses this runoff as input to the Lisflood routing model, producing a <span class="hlt">seasonal</span> river flow forecast out to 4 <span class="hlt">months</span> lead time, for the global river network. The <span class="hlt">seasonal</span> forecasts will be evaluated using the global river discharge reanalysis, and observations where available, to determine the potential value of the forecasts across the globe. The <span class="hlt">seasonal</span> forecasts will be presented as a new layer in the GloFAS interface, which will provide a global map of river catchments, indicating whether the catchment-averaged discharge forecast is showing abnormally high or low flows during the 4-<span class="hlt">month</span> lead time. Each catchment will display the corresponding forecast as an ensemble hydrograph of the weekly-averaged discharge forecast out to 4 <span class="hlt">months</span>, with percentile thresholds shown for comparison with the discharge climatology. The forecast visualisation is based on a combination of the current medium-range GloFAS forecasts and the operational EFAS (European Flood Awareness System) <span class="hlt">seasonal</span> outlook, and aims to effectively communicate the nature of a <span class="hlt">seasonal</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18172495','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18172495"><span>Vertical structure of recent Arctic <span class="hlt">warming</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Graversen, Rune G; Mauritsen, Thorsten; Tjernström, Michael; Källén, Erland; Svensson, Gunilla</p> <p>2008-01-03</p> <p>Near-surface <span class="hlt">warming</span> in the Arctic has been almost twice as large as the global average over recent decades-a phenomenon that is known as the 'Arctic amplification'. The underlying causes of this temperature amplification remain uncertain. The reduction in snow and ice cover that has occurred over recent decades may have played a role. Climate model experiments indicate that when global temperature rises, Arctic snow and ice cover retreats, causing excessive polar <span class="hlt">warming</span>. Reduction of the snow and ice cover causes albedo changes, and increased refreezing of sea ice during the cold <span class="hlt">season</span> and decreases in sea-ice thickness both increase heat flux from the ocean to the atmosphere. Changes in oceanic and atmospheric circulation, as well as cloud cover, have also been proposed to cause Arctic temperature amplification. Here we examine the vertical structure of temperature change in the Arctic during the late twentieth century using reanalysis data. We find evidence for temperature amplification well above the surface. Snow and ice feedbacks cannot be the main cause of the <span class="hlt">warming</span> aloft during the greater part of the year, because these feedbacks are expected to primarily affect temperatures in the lowermost part of the atmosphere, resulting in a pattern of <span class="hlt">warming</span> that we only observe in spring. A significant proportion of the observed temperature amplification must therefore be explained by mechanisms that induce <span class="hlt">warming</span> above the lowermost part of the atmosphere. We regress the Arctic temperature field on the atmospheric energy transport into the Arctic and find that, in the summer half-year, a significant proportion of the vertical structure of <span class="hlt">warming</span> can be explained by changes in this variable. We conclude that changes in atmospheric heat transport may be an important cause of the recent Arctic temperature amplification.</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" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22695877','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22695877"><span>Global <span class="hlt">warming</span> and allergy in Asia Minor.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bajin, Munir Demir; Cingi, Cemal; Oghan, Fatih; Gurbuz, Melek Kezban</p> <p>2013-01-01</p> <p>The earth is <span class="hlt">warming</span>, and it is <span class="hlt">warming</span> quickly. Epidemiological studies have demonstrated that global <span class="hlt">warming</span> is correlated with the frequency of pollen-induced respiratory allergy and allergic diseases. There is a body of evidence suggesting that the prevalence of allergic diseases induced by pollens is increasing in developed countries, a trend that is also evident in the Mediterranean area. Because of its mild winters and sunny days with dry summers, the Mediterranean area is different from the areas of central and northern Europe. Classical examples of allergenic pollen-producing plants of the Mediterranean climate include Parietaria, Olea and Cupressaceae. Asia Minor is a Mediterranean region that connects Asia and Europe, and it includes considerable coastal areas. Gramineae pollens are the major cause of <span class="hlt">seasonal</span> allergic rhinitis in Asia Minor, affecting 1.3-6.4 % of the population, in accordance with other European regions. This article emphasizes the importance of global climate change and anticipated increases in the prevalence and severity of allergic disease in Asia Minor, mediated through worsening air pollution and altered local and regional pollen production, from an otolaryngologic perspective.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://rosap.ntl.bts.gov/view/dot/34439','DOTNTL'); return false;" href="https://rosap.ntl.bts.gov/view/dot/34439"><span>Performance Measures of <span class="hlt">Warm</span> Asphalt Mixtures for Safe and Reliable Freight Transportation</span></a></p> <p><a target="_blank" href="http://ntlsearch.bts.gov/tris/index.do">DOT National Transportation Integrated Search</a></p> <p></p> <p>2009-04-01</p> <p><span class="hlt">Warm</span> mix asphalt (WMA) is an emerging technology that can allow asphalt to flow at a lower temperature for mixing, placing and compaction. The advantages of WMA include reduced fuel consumption, less carbon dioxide emission, longer paving <span class="hlt">season</span>, lon...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27570668','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27570668"><span>In Search of 'Birth <span class="hlt">Month</span> Genes': Using Existing Data Repositories to Locate Genes Underlying Birth <span class="hlt">Month</span>-Disease Relationships.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Boland, Mary Regina; Tatonetti, Nicholas P</p> <p>2016-01-01</p> <p>Prenatal and perinatal exposures vary <span class="hlt">seasonally</span> (e.g., sunlight, allergens) and many diseases are linked with variance in exposure. Epidemiologists often measure these changes using birth <span class="hlt">month</span> as a proxy for <span class="hlt">seasonal</span> variance. Likewise, Genome-Wide Association Studies have associated or implicated these same diseases with many genes. Both disparate data types (epidemiological and genetic) can provide key insights into the underlying disease biology. We developed an algorithm that links 1) epidemiological data from birth <span class="hlt">month</span> studies with 2) genetic data from published gene-disease association studies. Our framework uses existing data repositories - PubMed, DisGeNET and Gene Ontology - to produce a bipartite network that connects enriched <span class="hlt">seasonally</span> varying biofactorss with birth <span class="hlt">month</span> dependent diseases (BMDDs) through their overlapping developmental gene sets. As a proof-of-concept, we investigate 7 known BMDDs and highlight three important biological networks revealed by our algorithm and explore some interesting genetic mechanisms potentially responsible for the <span class="hlt">seasonal</span> contribution to BMDDs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1254389-land-atmosphere-coupling-manifested-warm-season-observations-southern-great-plains','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1254389-land-atmosphere-coupling-manifested-warm-season-observations-southern-great-plains"><span>Land-atmosphere coupling manifested in <span class="hlt">warm-season</span> observations on the U.S. southern great plains</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Phillips, Thomas J.; Klein, Stephen A.</p> <p>2014-01-28</p> <p>This study examines several observational aspects of land-atmosphere coupling on daily average time scales during <span class="hlt">warm</span> <span class="hlt">seasons</span> of the years 1997 to 2008 at the Department of Energy Atmospheric Radiation Measurement Program’s Southern Great Plains (SGP) Central Facility site near Lamont, Oklahoma. Characteristics of the local land-atmosphere coupling are inferred by analyzing the covariability of selected land and atmospheric variables that include precipitation and soil moisture, surface air temperature, relative humidity, radiant and turbulent fluxes, as well as low-level cloud base height and fractional coverage. For both the energetic and hydrological aspects of this coupling, it is found that large-scalemore » atmospheric forcings predominate, with local feedbacks of the land on the atmosphere being comparatively small much of the time. The weak land feedbacks are manifested by 1) the inability of soil moisture to comprehensively impact the coupled land-atmosphere energetics, and 2) the limited recycling of local surface moisture under conditions where most of the rainfall derives from convective cells that originate at remote locations. There is some evidence, nevertheless, of the local land feedback becoming stronger as the soil dries out in the aftermath of precipitation events, or on days when the local boundary-layer clouds are influenced by thermal updrafts known to be associated with convection originating at the surface. Finally, we also discuss potential implications of these results for climate-model representation of regional land-atmosphere coupling.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18983917','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18983917"><span>Impact of global <span class="hlt">warming</span> on viral diseases: what is the evidence?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zell, Roland; Krumbholz, Andi; Wutzler, Peter</p> <p>2008-12-01</p> <p>Global <span class="hlt">warming</span> is believed to induce a gradual climate change. Hence, it was predicted that tropical insects might expand their habitats thereby transmitting pathogens to humans. Although this concept is a conclusive presumption, clear evidence is still lacking--at least for viral diseases. Epidemiological data indicate that <span class="hlt">seasonality</span> of many diseases is further influenced by strong single weather events, interannual climate phenomena, and anthropogenic factors. So far, emergence of new diseases was unlinked to global <span class="hlt">warming</span>. Re-emergence and dispersion of diseases was correlated with translocation of pathogen-infected vectors or hosts. Coupled ocean/atmosphere circulations and 'global change' that also includes shifting of demographic, social, and economical conditions are important drivers of viral disease variability whereas global <span class="hlt">warming</span> at best contributes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70168444','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70168444"><span>Rapid and highly variable <span class="hlt">warming</span> of lake surface waters around the globe</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>O'Reilly, Catherine; Sharma, Sapna; Gray, Derek; Hampton, Stephanie; Read, Jordan S.; Rowley, Rex J.; Schneider, Philipp; Lenters, John D.; McIntyre, Peter B.; Kraemer, Benjamin M.; Weyhenmeyer, Gesa A.; Straile, Dietmar; Dong, Bo; Adrian, Rita; Allan, Mathew G.; Anneville, Orlane; Arvola, Lauri; Austin, Jay; Bailey, John L.; Baron, Jill S.; Brookes, Justin D; de Eyto, Elvira; Dokulil, Martin T.; Hamilton, David P.; Havens, Karl; Hetherington, Amy L.; Higgins, Scott N.; Hook, Simon; Izmest'eva, Lyubov R.; Jöhnk, Klaus D.; Kangur, Külli; Kasprzak, Peter; Kumagai, Michio; Kuusisto, Esko; Leshkevich, George; Livingstone, David M.; MacIntyre, Sally; May, Linda; Melack, John M.; Mueller-Navara, Doerthe C.; Naumenko, Mikhail; Noges, Peeter; Noges, Tiina; North, Ryan P.; Plisnier, Pierre-Denis; Rigosi, Anna; Rimmer, Alon; Rogora, Michela; Rudstam, Lars G.; Rusak, James A.; Salmaso, Nico; Samal, Nihar R.; Schindler, Daniel E.; Schladow, Geoffrey; Schmid, Martin; Schmidt, Silke R.; Silow, Eugene A.; Soylu, M. Evren; Teubner, Katrin; Verburg, Piet; Voutilainen, Ari; Watkinson, Andrew; Williamson, Craig E.; Zhang, Guoqing</p> <p>2015-01-01</p> <p>In this first worldwide synthesis of in situ and satellite-derived lake data, we find that lake summer surface water temperatures rose rapidly (global mean = 0.34°C decade−1) between 1985 and 2009. Our analyses show that surface water <span class="hlt">warming</span> rates are dependent on combinations of climate and local characteristics, rather than just lake location, leading to the counterintuitive result that regional consistency in lake <span class="hlt">warming</span> is the exception, rather than the rule. The most rapidly <span class="hlt">warming</span> lakes are widely geographically distributed, and their <span class="hlt">warming</span> is associated with interactions among different climatic factors—from <span class="hlt">seasonally</span> ice-covered lakes in areas where temperature and solar radiation are increasing while cloud cover is diminishing (0.72°C decade−1) to ice-free lakes experiencing increases in air temperature and solar radiation (0.53°C decade−1). The pervasive and rapid <span class="hlt">warming</span> observed here signals the urgent need to incorporate climate impacts into vulnerability assessments and adaptation efforts for lakes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25777068','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25777068"><span>Rotavirus <span class="hlt">seasonality</span> in urban sewage from Argentina: effect of meteorological variables on the viral load and the genetic diversity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Barril, P A; Fumian, T M; Prez, V E; Gil, P I; Martínez, L C; Giordano, M O; Masachessi, G; Isa, M B; Ferreyra, L J; Ré, V E; Miagostovich, M; Pavan, J V; Nates, S V</p> <p>2015-04-01</p> <p>In Argentina, the rotavirus disease exhibits <span class="hlt">seasonal</span> variations, being most prevalent in the fall and winter <span class="hlt">months</span>. To deepen the understanding of rotavirus <span class="hlt">seasonality</span> in our community, the influence of meteorological factors on the rotavirus load and the genetic diversity in urban raw sewage from Córdoba city, Argentina were evaluated. Wastewater samples were collected <span class="hlt">monthly</span> during a three-year study period and viral particles were concentrated by polyethylene glycol precipitation. RT-nested PCR was applied for rotavirus detection, and VP7/VP4 characterization and real-time PCR for rotavirus quantification. Both molecular techniques showed relatively similar sensitivity rates and revealed rotavirus presence in urban wastewater in cold and <span class="hlt">warm</span> <span class="hlt">seasons</span>, indicating its circulation in the local community all year round. However, a slight trend for rotavirus circulation was noted by real-time PCR in the fall and winter <span class="hlt">seasons</span>, showing a significantly higher peak of rotavirus concentration at mean temperatures lower than 18°C and also higher, although not statistically different during drier weather. VP7 and VP4 gene characterization showed that G1 and P[8] genotypes were dominant, and temporal variations in genotype distribution were not observed. Rotavirus spread is complex and our results point out that weather factors alone cannot explain the <span class="hlt">seasonal</span> quantitative pattern of the rotavirus disease. Therefore, alternative transmission routes, changes in human behavior and susceptibility, and the stability and survivability of the virus might all together contribute to the <span class="hlt">seasonality</span> of rotavirus. The results obtained here provide evidence regarding the dynamics of rotavirus circulation and maintenance in Argentina. Copyright © 2015 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17..507B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17..507B"><span>Highly-<span class="hlt">seasonal</span> monsoons controlled by Central Asian Eocene epicontinental sea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bougeois, Laurie; Tindall, Julia; de Rafélis, Marc; Reichart, Gert-Jan; de Nooijer, Lennart; Dupont-Nivet, Guillaume</p> <p>2015-04-01</p> <p>Modern Asian climate is mainly controlled by <span class="hlt">seasonal</span> reverse winds driven by continent-ocean thermal contrast. This yields monsoon pattern characterized by a strong <span class="hlt">seasonality</span> in terms of precipitation and temperature and a duality between humidity along southern and eastern Asia and aridity in Central Asia. According to climate models, Asian Monsoons and aridification have been governed by Tibetan plateau uplift, global climate changes and the retreat of a vast epicontinental sea (the Proto-Paratethys sea) that used to cover Eurasia in Eocene times (55 to 34 Myr ago). Evidence for Asian aridification and monsoons a old as Eocene, are emerging from proxy and model data, however, the role of the Proto-Paratethys sea remains to be established by proxy data. By applying a novel infra-annual geochemical multi-proxy methodology on Eocene oyster shells of the Proto-Paratethys sea and comparing results to climate simulations, we show that the Central Asian region was generally arid with high <span class="hlt">seasonality</span> from hot and arid summers to wetter winters. This high <span class="hlt">seasonality</span> in Central Asia supports a monsoonal circulation was already established although the climate pattern was significantly different than today. During winter <span class="hlt">months</span>, a strong influence of the Proto-Paratethys moisture is indicated by enhanced precipitations significantly higher than today. Precipitation probably dwindled because of the subsequent sea retreat as well as the uplift of the Tibetan and Pamir mountains shielding the westerlies. During Eocene summers, the local climate was hotter and more arid than today despite the presence of the Proto Paratethys. This may be explained by warmer Eocene global conditions with a strong anticyclonic Hadley cell descending at Central Asian latitudes (25 to 45 N). urthermore, the Tibetan plateau emerging at this time to the south must have already contributed a stronger Foehn effect during summer <span class="hlt">months</span> bringing <span class="hlt">warm</span> and dry air into Central Asia. Proto</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27393745','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27393745"><span><span class="hlt">Seasonal</span> Variation in Emergency Department Visits Among Pediatric Headache Patients.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pakalnis, A; Heyer, G L</p> <p>2016-09-01</p> <p>To ascertain whether <span class="hlt">seasonal</span> variation occurs in emergency department (ED) visits for headache among children and adolescents. A retrospective review was conducted using the electronic medical records of ED visits for headache at a tertiary children's hospital through calendar years 2010-2014. Using ICD-9 diagnostic codes for headache and migraine, the numbers of headache visits were determined and compared by <span class="hlt">season</span> and during school <span class="hlt">months</span> vs summer <span class="hlt">months</span>. A total of 6572 headache visits occurred. Headache visits increased during the fall <span class="hlt">season</span> (133 ± 27 visits per <span class="hlt">month</span>) compared with other <span class="hlt">seasons</span> (101 ± 19 visits per <span class="hlt">month</span>), P ≤ .002, but did not differ when comparing school <span class="hlt">months</span> (113 ± 25 visits per <span class="hlt">month</span>) and summer <span class="hlt">months</span> (100 ± 24 visits per <span class="hlt">month</span>), P = .1. The corresponding increase in ED visits during the fall <span class="hlt">season</span> coincides with the start of the school year. Academic stressors and the change in daily schedule may lead to more headaches and more ED headache visits among school-aged youth. © 2016 American Headache Society.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23926903','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23926903"><span>The intrinsic growth rate as a predictor of population viability under climate <span class="hlt">warming</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Amarasekare, Priyanga; Coutinho, Renato M</p> <p>2013-11-01</p> <p>1. Lately, there has been interest in using the intrinsic growth rate (rm) to predict the effects of climate <span class="hlt">warming</span> on ectotherm population viability. However, because rm is calculated using the Euler-Lotka equation, its reliability in predicting population persistence depends on whether ectotherm populations can achieve a stable age/stage distribution in thermally variable environments. Here, we investigate this issue using a mathematical framework that incorporates mechanistic descriptions of temperature effects on vital rates into a stage-structured population model that realistically captures the temperature-induced variability in developmental delays that characterize ectotherm life cycles. 2. We find that populations experiencing <span class="hlt">seasonal</span> temperature variation converge to a stage distribution whose intra-annual pattern remains invariant across years. As a result, the mean annual per capita growth rate also remains constant between years. The key insight is the mechanism that allows populations converge to a stationary stage distribution. Temperature effects on the biochemical processes (e.g. enzyme kinetics, hormonal regulation) that underlie life-history traits (reproduction, development and mortality) exhibit well-defined thermodynamical properties (e.g. changes in entropy and enthalpy) that lead to predictable outcomes (e.g. reduction in reaction rates or hormonal action at temperature extremes). As a result, life-history traits exhibit a systematic and predictable response to <span class="hlt">seasonal</span> temperature variation. This in turn leads to temporally predictable temperature responses of the stage distribution and the per capita growth rate. 3. When climate <span class="hlt">warming</span> causes an increase in the mean annual temperature and/or the amplitude of <span class="hlt">seasonal</span> fluctuations, the population model predicts the mean annual per capita growth rate to decline to zero within 100 years when <span class="hlt">warming</span> is slow relative to the developmental period of the organism (0.03-0.05°C per year) and to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3468463','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3468463"><span>Cambial Growth <span class="hlt">Season</span> of Brevi-Deciduous Brachystegia spiciformis Trees from South Central Africa Restricted to Less than Four <span class="hlt">Months</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Trouet, Valérie; Mukelabai, Mukufute; Verheyden, Anouk; Beeckman, Hans</p> <p>2012-01-01</p> <p>We investigate cambial growth periodicity in Brachystegia spiciformis, a dominant tree species in the <span class="hlt">seasonally</span> dry miombo woodland of southern Africa. To better understand how the brevi-deciduous (experiencing a short, drought-induced leaf fall period) leaf phenology of this species can be linked to a distinct period of cambial activity, we applied a bi-weekly pinning to six trees in western Zambia over the course of one year. Our results show that the onset and end of cambial growth was synchronous between trees, but was not concurrent with the onset and end of the rainy <span class="hlt">season</span>. The relatively short (three to four <span class="hlt">months</span> maximum) cambial growth <span class="hlt">season</span> corresponded to the core of the rainy <span class="hlt">season</span>, when 75% of the annual precipitation fell, and to the period when the trees were at full photosynthetic capacity. Tree-ring studies of this species have found a significant relationship between annual tree growth and precipitation, but we did not observe such a correlation at intra-annual resolution in this study. Furthermore, a substantial rainfall event occurring after the end of the cambial growth <span class="hlt">season</span> did not induce xylem initiation or false ring formation. Low sample replication should be taken into account when interpreting the results of this study, but our findings can be used to refine the carbon allocation component of process-based terrestrial ecosystem models and can thus contribute to a more detailed estimation of the role of the miombo woodland in the terrestrial carbon cycle. Furthermore, we provide a physiological foundation for the use of Brachystegia spiciformis tree-ring records in paleoclimate research. PMID:23071794</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2467415','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2467415"><span><span class="hlt">Seasonality</span> of cholera from 1974 to 2005: a review of global patterns</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Emch, Michael; Feldacker, Caryl; Islam, M Sirajul; Ali, Mohammad</p> <p>2008-01-01</p> <p>Background The <span class="hlt">seasonality</span> of cholera is described in various study areas throughout the world. However, no study examines how temporal cycles of the disease vary around the world or reviews its hypothesized causes. This paper reviews the literature on the <span class="hlt">seasonality</span> of cholera and describes its temporal cycles by compiling and analyzing 32 years of global cholera data. This paper also provides a detailed literature review on regional patterns and environmental and climatic drivers of cholera patterns. Data, Methods, and Results Cholera data are compiled from 1974 to 2005 from the World Health Organization Weekly Epidemiological Reports, a database that includes all reported cholera cases in 140 countries. The data are analyzed to measure whether <span class="hlt">season</span>, latitude, and their interaction are significantly associated with the country-level number of outbreaks in each of the 12 preceding <span class="hlt">months</span> using separate negative binomial regression models for northern, southern, and combined hemispheres. Likelihood ratios tests are used to determine the model of best fit. The results suggest that cholera outbreaks demonstrate <span class="hlt">seasonal</span> patterns in higher absolute latitudes, but closer to the equator, cholera outbreaks do not follow a clear <span class="hlt">seasonal</span> pattern. Conclusion The findings suggest that environmental and climatic factors partially control the temporal variability of cholera. These results also indirectly contribute to the growing debate about the effects of climate change and global <span class="hlt">warming</span>. As climate change threatens to increase global temperature, resulting rises in sea levels and temperatures may influence the temporal fluctuations of cholera, potentially increasing the frequency and duration of cholera outbreaks. PMID:18570659</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22692020','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22692020"><span>Single measurement of serum 25(OH)D: is classification into <span class="hlt">month</span>-specific cutpoints useful in accounting for <span class="hlt">seasonal</span> variation?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Saliba, W; Barnett-Griness, O; Rennert, G</p> <p>2012-09-01</p> <p>Classification into <span class="hlt">month</span>-specific cutpoints is used to minimize misclassification associated with single measurement of serum 25(OH)D. This study aims to evaluate this strategy, and to compare it with the widely used classification into overall cutpoints. For this purpose, we studied 69,553 subjects in whom serum 25(OH)D was tested on two different occasions. The level of agreement between the quartiles of the first and second tests was 43.8% between the <span class="hlt">month</span>-specific quartiles and 43.1% between the overall quartiles. The level of agreement between the quartiles of the two approaches was 80.0% and 94.3% in the first and second test, respectively. The extent of <span class="hlt">seasonal</span> variation (summer-autumn as compared with winter-spring) of serum 25(OH)D was higher in males and in Jews, inversely associated with baseline levels, body mass index and age, and directly associated with socioeconomic class. The <span class="hlt">month</span>-specific cutpoint strategy does not seem to offer advantage over the overall cutpoints strategy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3930050','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3930050"><span>Snow cover and extreme winter <span class="hlt">warming</span> events control flower abundance of some, but not all species in high arctic Svalbard</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Semenchuk, Philipp R; Elberling, Bo; Cooper, Elisabeth J</p> <p>2013-01-01</p> <p>Abstract The High Arctic winter is expected to be altered through ongoing and future climate change. Winter precipitation and snow depth are projected to increase and melt out dates change accordingly. Also, snow cover and depth will play an important role in protecting plant canopy from increasingly more frequent extreme winter <span class="hlt">warming</span> events. Flower production of many Arctic plants is dependent on melt out timing, since <span class="hlt">season</span> length determines resource availability for flower preformation. We erected snow fences to increase snow depth and shorten growing <span class="hlt">season</span>, and counted flowers of six species over 5 years, during which we experienced two extreme winter <span class="hlt">warming</span> events. Most species were resistant to snow cover increase, but two species reduced flower abundance due to shortened growing <span class="hlt">seasons</span>. Cassiope tetragona responded strongly with fewer flowers in deep snow regimes during years without extreme events, while Stellaria crassipes responded partly. Snow pack thickness determined whether winter <span class="hlt">warming</span> events had an effect on flower abundance of some species. <span class="hlt">Warming</span> events clearly reduced flower abundance in shallow but not in deep snow regimes of Cassiope tetragona, but only marginally for Dryas octopetala. However, the affected species were resilient and individuals did not experience any long term effects. In the case of short or cold summers, a subset of species suffered reduced reproductive success, which may affect future plant composition through possible cascading competition effects. Extreme winter <span class="hlt">warming</span> events were shown to expose the canopy to cold winter air. The following summer most of the overwintering flower buds could not produce flowers. Thus reproductive success is reduced if this occurs in subsequent years. We conclude that snow depth influences flower abundance by altering <span class="hlt">season</span> length and by protecting or exposing flower buds to cold winter air, but most species studied are resistant to changes. Winter <span class="hlt">warming</span> events, often</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.cpc.ncep.noaa.gov/products/predictions/30day','SCIGOVWS'); return false;" href="http://www.cpc.ncep.noaa.gov/products/predictions/30day"><span>Climate Prediction Center - <span class="hlt">monthly</span> Outlook</span></a></p> <p><a target="_blank" href="http://www.science.gov/aboutsearch.html">Science.gov Websites</a></p> <p></p> <p></p> <p>Weather Service NWS logo - Click to go to the NWS home page <em>Climate</em> Prediction Center Site Map News Outlooks <span class="hlt">monthly</span> <em>Climate</em> Outlooks Banner OFFICIAL Forecasts June 2018 [UPDATED <span class="hlt">MONTHLY</span> FORECASTS SERVICE <em>CHANGE</em> NOTICE] [EXPERIMENTAL TWO-CLASS <span class="hlt">SEASONAL</span> FORECASTS] Text-Format Discussions <span class="hlt">Monthly</span> Long Lead 30</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4987647','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4987647"><span>Spatiotemporal Divergence of the <span class="hlt">Warming</span> Hiatus over Land Based on Different Definitions of Mean Temperature</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhou, Chunlüe; Wang, Kaicun</p> <p>2016-01-01</p> <p>Existing studies of the recent <span class="hlt">warming</span> hiatus over land are primarily based on the average of daily minimum and maximum temperatures (T2). This study compared regional <span class="hlt">warming</span> rates of mean temperature based on T2 and T24 calculated from hourly observations available from 1998 to 2013. Both T2 and T24 show that the <span class="hlt">warming</span> hiatus over land is apparent in the mid-latitudes of North America and Eurasia, especially in cold <span class="hlt">seasons</span>, which is closely associated with the negative North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) and cold air propagation by the Arctic-original northerly wind anomaly into mid-latitudes. However, the <span class="hlt">warming</span> rates of T2 and T24 are significantly different at regional and <span class="hlt">seasonal</span> scales because T2 only samples air temperature twice daily and cannot accurately reflect land-atmosphere and incoming radiation variations in the temperature diurnal cycle. The trend has a standard deviation of 0.43 °C/decade for T2 and 0.41 °C/decade for T24, and 0.38 °C/decade for their trend difference in 5° × 5° grids. The use of T2 amplifies the regional contrasts of the <span class="hlt">warming</span> rate, i.e., the trend underestimation in the US and overestimation at high latitudes by T2. PMID:27531421</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29127796','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29127796"><span>Effects of <span class="hlt">warming</span> on N2O fluxes in a boreal peatland of Permafrost region, Northeast China.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cui, Qian; Song, Changchun; Wang, Xianwei; Shi, Fuxi; Yu, Xueyang; Tan, Wenwen</p> <p>2018-03-01</p> <p>Climate <span class="hlt">warming</span> is expected to increasingly influence boreal peatlands and alter their greenhouse gases emissions. However, the effects of <span class="hlt">warming</span> on N 2 O fluxes and the N 2 O budgets were ignored in boreal peatlands. Therefore, in a boreal peatland of permafrost zone in Northeast China, a simulated <span class="hlt">warming</span> experiment was conducted to investigate the effects of <span class="hlt">warming</span> on N 2 O fluxes in Betula. Fruticosa community (B. Fruticosa) and Ledum. palustre community (L. palustre) during the growing <span class="hlt">seasons</span> from 2013 to 2015. Results showed that <span class="hlt">warming</span> treatment increased air temperature at 1.5m aboveground and soil temperature at 5cm depth by 0.6°C and 2°C, respectively. The average <span class="hlt">seasonal</span> N 2 O fluxes ranged from 6.62 to 9.34μgm -2 h -1 in the <span class="hlt">warming</span> plot and ranged from 0.41 to 4.55μgm -2 h -1 in the control plots. <span class="hlt">Warming</span> treatment increased N 2 O fluxes by 147% and transformed the boreal peatlands from a N 2 O sink to a source. The primary driving factors for N 2 O fluxes were soil temperature and active layer depth, whereas soil moisture showed a weak correlation with N 2 O fluxes. The results indicated that <span class="hlt">warming</span> promoted N 2 O fluxes by increasing soil temperature and active layer depth in a boreal peatland of permafrost zone in Northeast China. Moreover, elevated N 2 O fluxes persisted in this region will potentially drive a noncarbon feedback to ongoing climate change. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26119211','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26119211"><span>Canopy <span class="hlt">warming</span> caused photosynthetic acclimation and reduced seed yield in maize grown at ambient and elevated [CO2 ].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ruiz-Vera, Ursula M; Siebers, Matthew H; Drag, David W; Ort, Donald R; Bernacchi, Carl J</p> <p>2015-11-01</p> <p>Rising atmospheric CO2 concentration ([CO2 ]) and attendant increases in growing <span class="hlt">season</span> temperature are expected to be the most important global change factors impacting production agriculture. Although maize is the most highly produced crop worldwide, few studies have evaluated the interactive effects of elevated [CO2 ] and temperature on its photosynthetic physiology, agronomic traits or biomass, and seed yield under open field conditions. This study investigates the effects of rising [CO2 ] and warmer temperature, independently and in combination, on maize grown in the field throughout a full growing <span class="hlt">season</span>. Free-air CO2 enrichment (FACE) technology was used to target atmospheric [CO2 ] to 200 μmol mol(-1) above ambient [CO2 ] and infrared heaters to target a plant canopy increase of 3.5 °C, with actual <span class="hlt">season</span> mean heating of ~2.7 °C, mimicking conditions predicted by the second half of this century. Photosynthetic gas-exchange parameters, leaf nitrogen and carbon content, leaf water potential components, and developmental measurements were collected throughout the <span class="hlt">season</span>, and biomass and yield were measured at the end of the growing <span class="hlt">season</span>. As predicted for a C4 plant, elevated [CO2 ] did not stimulate photosynthesis, biomass, or yield. Canopy <span class="hlt">warming</span> caused a large shift in aboveground allocation by stimulating <span class="hlt">season</span>-long vegetative biomass and decreasing reproductive biomass accumulation at both CO2 concentrations, resulting in decreased harvest index. <span class="hlt">Warming</span> caused a reduction in photosynthesis due to down-regulation of photosynthetic biochemical parameters and the decrease in the electron transport rate. The reduction in seed yield with <span class="hlt">warming</span> was driven by reduced photosynthetic capacity and by a shift in aboveground carbon allocation away from reproduction. This field study portends that future <span class="hlt">warming</span> will reduce yield in maize, and this will not be mitigated by higher atmospheric [CO2 ] unless appropriate adaptation traits can be introduced</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ncifrederick.cancer.gov/about/theposter/content/fire-safety-during-holiday-season','NCI'); return false;" href="https://ncifrederick.cancer.gov/about/theposter/content/fire-safety-during-holiday-season"><span>Fire Safety During the Holiday <span class="hlt">Season</span> | Poster</span></a></p> <p><a target="_blank" href="http://www.cancer.gov">Cancer.gov</a></p> <p></p> <p></p> <p>Winter is here, and that means holiday decorations, a <span class="hlt">warm</span> hearth, and (hopefully) plenty of homecooked meals. Unfortunately, winter also brings numerous fire hazards both at work and around the house. This year, as you shop, decorate, and celebrate, keep these safety tips in mind to ensure a safe and enjoyable holiday <span class="hlt">season</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21330268','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21330268"><span><span class="hlt">Seasonality</span> in sales of nicotine replacement therapies: patterns and implications for tobacco control.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chandra, Siddharth; Gitchell, Joseph G; Shiffman, Saul</p> <p>2011-05-01</p> <p>Over the counter, nicotine replacement therapies (NRTs) are the most widely used smoking cessation treatment. This study sheds light on the <span class="hlt">seasonality</span> of sales of NRT. A <span class="hlt">seasonal</span> adjustment algorithm was applied to data on the sales of NRT products for 50 metro markets in the United States to test for and characterize <span class="hlt">seasonality</span> in NRT sales. Granger's test was applied to the data to test whether changes in NRT sales systematically predicted changes in cigarette sales 1 <span class="hlt">month</span> later. The results show (a) that sales of NRT products are <span class="hlt">seasonal</span>, (b) that the <span class="hlt">seasonality</span> pattern is the opposite of the <span class="hlt">seasonality</span> pattern for cigarette sales, (c) that <span class="hlt">seasonally</span> higher NRT sales in a given <span class="hlt">month</span> tend to be followed by <span class="hlt">seasonally</span> lower cigarette sales in the following <span class="hlt">month</span>, and (d) that <span class="hlt">seasonally</span> high <span class="hlt">months</span> for NRT sales (January to March) correspond to <span class="hlt">seasonally</span> low <span class="hlt">months</span> for cigarette sales. NRT sales show a strong <span class="hlt">seasonality</span> pattern that is the opposite of the <span class="hlt">seasonality</span> pattern for cigarette sales. These patterns are indicative of <span class="hlt">seasonal</span> variations in quitting behavior.</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" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140012052','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140012052"><span>An Assessment of the Skill of GEOS-5 <span class="hlt">Seasonal</span> Forecasts</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ham, Yoo-Geun; Schubert, Siegfried D.; Rienecker, Michele M.</p> <p>2013-01-01</p> <p>The <span class="hlt">seasonal</span> forecast skill of the NASA Global Modeling and Assimilation Office coupled global climate model (CGCM) is evaluated based on an ensemble of 9-<span class="hlt">month</span> lead forecasts for the period 1993 to 2010. The results from the current version (V2) of the CGCM consisting of the GEOS-5 AGM coupled to the MOM4 ocean model are compared with those from an earlier version (V1) in which the AGCM (the NSIPP model) was coupled to the Poseidon Ocean Model. It was found that the correlation skill of the Sea Surface Temperature (SST) forecasts is generally better in V2, especially over the sub-tropical and tropical central and eastern Pacific, Atlantic, and Indian Ocean. Furthermore, the improvement in skill in V2 mainly comes from better forecasts of the developing phase of ENSO from boreal spring to summer. The skill of ENSO forecasts initiated during the boreal winter <span class="hlt">season</span>, however, shows no improvement in terms of correlation skill, and is in fact slightly worse in terms of root mean square error (RMSE). The degradation of skill is found to be due to an excessive ENSO amplitude. For V1, the ENSO amplitude is too strong in forecasts starting in boreal spring and summer, which causes large RMSE in the forecast. For V2, the ENSO amplitude is slightly stronger than that in observations and V1 for forecasts starting in boreal winter <span class="hlt">season</span>. An analysis of the terms in the SST tendency equation, shows that this is mainly due to an excessive zonal advective feedback. In addition, V2 forecasts that are initiated during boreal winter <span class="hlt">season</span>, exhibit a slower phase transition of El Nino, which is consistent with larger amplitude of ENSO after the ENSO peak <span class="hlt">season</span>. It is found that this is due to weak discharge of equatorial <span class="hlt">Warm</span> Water Volume (WWV). In both observations and V1, the discharge of equatorial WWV leads the equatorial geostrophic easterly current so as to damp the El Nino starting in January. This process is delayed by about 2 <span class="hlt">months</span> in V2 due to the slower phase</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1912077R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1912077R"><span>Aquifer Thermal Energy Storage for <span class="hlt">Seasonal</span> Thermal Energy Balance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rostampour, Vahab; Bloemendal, Martin; Keviczky, Tamas</p> <p>2017-04-01</p> <p>Aquifer Thermal Energy Storage (ATES) systems allow storing large quantities of thermal energy in subsurface aquifers enabling significant energy savings and greenhouse gas reductions. This is achieved by injection and extraction of water into and from saturated underground aquifers, simultaneously. An ATES system consists of two wells and operates in a <span class="hlt">seasonal</span> mode. One well is used for the storage of cold water, the other one for the storage of heat. In <span class="hlt">warm</span> <span class="hlt">seasons</span>, cold water is extracted from the cold well to provide cooling to a building. The temperature of the extracted cold water increases as it passes through the building climate control systems and then gets simultaneously, injected back into the <span class="hlt">warm</span> well. This procedure is reversed during cold <span class="hlt">seasons</span> where the flow direction is reversed such that the warmer water is extracted from the <span class="hlt">warm</span> well to provide heating to a building. From the perspective of building climate comfort systems, an ATES system is considered as a <span class="hlt">seasonal</span> storage system that can be a heat source or sink, or as a storage for thermal energy. This leads to an interesting and challenging optimal control problem of the building climate comfort system that can be used to develop a <span class="hlt">seasonal</span>-based energy management strategy. In [1] we develop a control-oriented model to predict thermal energy balance in a building climate control system integrated with ATES. Such a model however cannot cope with off-nominal but realistic situations such as when the wells are completely depleted, or the start-up phase of newly installed wells, etc., leading to direct usage of aquifer ambient temperature. Building upon our previous work in [1], we here extend the mathematical model for ATES system to handle the above mentioned more realistic situations. Using our improved models, one can more precisely predict system behavior and apply optimal control strategies to manage the building climate comfort along with energy savings and greenhouse gas reductions</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.B33E0671J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.B33E0671J"><span>Leaf Respiratory Acclimation: Magnitude of Acclimation to the Long-term <span class="hlt">Warming</span> in Tallgrass Prairie</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jung, C. G.; Peng, F.; Luo, Y.</p> <p>2016-12-01</p> <p>Plant respiration has a positive response with temperature; hence, the plant under warmer climate makes plant releases more CO2. However, plant leaf can acclimate to the warmer climate so that plant leaf respiratory acclimation contributes less positive feedback between climate <span class="hlt">warming</span> and ecosystem CO2 release. In order to examine the feedback between ecosystem and evolution of carbon dioxide due to global <span class="hlt">warming</span>, we conducted the experiment of <span class="hlt">warming</span> and clipping as mimicking grazing effect in a tall grass prairie in central Oklahoma, US since November 1999. The <span class="hlt">warming</span> plot's air and soil temperature show 1.1 °C and 2.3 °C higher than ambient, respectively. Since our experiment has been over 16 years, the plot's species compositions and plant richness have changed so far. Most species composition events occurred at the clipping plot; therefore, we selected the plants within unclipped plots to see whether plants that exposed long-term <span class="hlt">warming</span>, play a role of thermal acclimation and how those major plant species across experimental site possess difference magnitude of acclimation. We have investigated five species, one legume, one forb, and three of C4 grass: Illinois bundle (Desmanthus illinoensis, C3), stiff goldenrod (Solidago rigida, C3), King Ranch bluestem (Bothriochloa ischaemum, C4), Indian grass (Sorghastrum nutans, C4), and Little bluestem (Schizachyrium scoparium, C4). Data has collected from May as the first <span class="hlt">month</span> of growing <span class="hlt">season</span> in our field site in 2016. In our results, measurements in +2 °C <span class="hlt">warming</span> show strong acclimation across the species (185% ±41% s.e.m. among species). The strongest acclimation occurred by stiff goldenrod (309%). The lowest acclimation rate is 51% in Illinois bundle, as well as the partial acclimation. The other three C4 grass species have 188% acclimation rate (±37% s.e.m. among species). Whether different plant species have a different capability of acclimation or respond through different way as shown various</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B34B..01N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B34B..01N"><span>Controls of Methane Dynamics and Emissions in an Arctic <span class="hlt">Warming</span> Experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nielsen, C. S.; Elberling, B.; Michelsen, A.; Strobel, B. W.; Wulff, K.; Banyasz, I.</p> <p>2015-12-01</p> <p>Climatic changes have resulted in increasing air temperatures across the Arctic. This may increase anaerobic decomposition of soil organic matter to methane (CH4) in wetlands and increase plant growth and thereby production of substrate. Little is known about how <span class="hlt">seasonal</span> variations in dissolved CH4 in soil water, substrate availability, and the effect of <span class="hlt">warming</span> affect arctic wetland dynamics of CH4 production and emission. In 2013 we established two experiments in a fen at Disko Island, W Greenland; one with year round <span class="hlt">warming</span> by open-top chambers and removal of shrubs, and one with removal of the aerenchymatous sedge Carex aquatilis ssp. stans. Throughout the growing <span class="hlt">season</span> 2014 we measured how the treatments affected CH4 emissions, dissolved CH4 in the soil water, and substrate availability. Ecosystem CH4 emissions peaked at August 5th 2014 (7.5 μmol m-2 h-1) without coinciding with time of highest concentrations of dissolved CH4 or acetate indicating a decoupling between production and emission of CH4. The peak in dissolved CH4 concentration, at ten cm depth (1368 ppm, September 18th 2014), followed the peak in concentration of acetate in the same depth (0.30 ppm, August 30th 2014) highlighting the importance of this substance as a substrate for methanogenesis. C. aquatilis ssp. stans accounted for 60% and 77% of the ecosystem CH4 emissions in areas of the fen with water table above and below soil surface showing the importance of the presence of this species to serve as a pipe for CH4 emission which is bypassing the upper soil zone and potential methane oxidation. Throughout the <span class="hlt">season</span>, <span class="hlt">warming</span> increased the air temperature at soil surface by on average 0.89°C and occasionally <span class="hlt">warming</span> and shrub removal increased soil temperature in 2 and 5 cm depth, but there was no effect of the treatments on the CH4 emissions indicating that this wetland is quite resilient towards future climate change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70179335','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70179335"><span><span class="hlt">Warming</span> and provenance limit tree recruitment across and beyond the elevation range of subalpine forest</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kueppers, Lara M.; Conlisk, Erin; Castanha, Cristina; Moyes, Andrew B.; Germino, Matthew; de Valpine, Perry; Torn, Margaret S.; Mitton, Jeffry B.</p> <p>2017-01-01</p> <p>Climate niche models project that subalpine forest ranges will extend upslope with climate <span class="hlt">warming</span>. These projections assume that the climate suitable for adult trees will be adequate for forest regeneration, ignoring climate requirements for seedling recruitment, a potential demographic bottleneck. Moreover, local genetic adaptation is expected to facilitate range expansion, with tree populations at the upper forest edge providing the seed best adapted to the alpine. Here, we test these expectations using a novel combination of common gardens, seeded with two widely distributed subalpine conifers, and climate manipulations replicated at three elevations. Infrared heaters raised temperatures in heated plots, but raised temperatures more in the forest than at or above treeline because strong winds at high elevation reduced heating efficiency. Watering increased <span class="hlt">season</span>-average soil moisture similarly across sites. Contrary to expectations, <span class="hlt">warming</span> reduced Engelmann spruce recruitment at and above treeline, as well as in the forest. <span class="hlt">Warming</span> reduced limber pine first-year recruitment in the forest, but had no net effect on fourth-year recruitment at any site. Watering during the snow-free <span class="hlt">season</span> alleviated some negative effects of <span class="hlt">warming</span>, indicating that <span class="hlt">warming</span> exacerbated water limitations. Contrary to expectations of local adaptation, low-elevation seeds of both species initially recruited more strongly than high-elevation seeds across the elevation gradient, although the low-provenance advantage diminished by the fourth year for Engelmann spruce, likely due to small sample sizes. High- and low-elevation provenances responded similarly to <span class="hlt">warming</span> across sites for Engelmann spruce, but differently for limber pine. In the context of increasing tree mortality, lower recruitment at all elevations with <span class="hlt">warming</span>, combined with lower quality, high-provenance seed being most available for colonizing the alpine, portends range contraction for Engelmann spruce. The lower</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26566809','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26566809"><span>Temperature effects on seaweed-sustaining top-down control vary with <span class="hlt">season</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Werner, Franziska J; Graiff, Angelika; Matthiessen, Birte</p> <p>2016-03-01</p> <p>Rising seawater temperature and CO2 concentrations (ocean acidification) represent two of the most influential factors impacting marine ecosystems in the face of global climate change. In ecological climate change research, full-factorial experiments performed across <span class="hlt">seasons</span> in multispecies, cross-trophic-level settings are essential as they permit a more realistic estimation of direct and indirect effects as well as the relative importance of the effects of both major environmental stressors on ecosystems. In benthic mesocosm experiments, we tested the responses of coastal Baltic Sea Fucus vesiculosus communities to elevated seawater temperature and CO2 concentrations across four <span class="hlt">seasons</span> of one year. While increasing [CO2] levels had only minor effects, <span class="hlt">warming</span> had strong and persistent effects on grazers, and the resulting effects on the Fucus community were found to be <span class="hlt">season</span> dependent. In late summer, a temperature-driven collapse of grazers caused a cascading effect from the consumers to the foundation species, resulting in overgrowth of Fucus thalli by epiphytes. In fall/winter (outside the growing <span class="hlt">season</span> of epiphytes), intensified grazing under <span class="hlt">warming</span> resulted in a significant reduction in Fucus biomass. Thus, we were able to confirm the prediction that future increases in water temperatures will influence marine food-web processes by altering top-down control, but we were also able to show that specific consequences for food-web structure depend on the <span class="hlt">season</span>. Since F. vesiculosus is the dominant habitat-forming brown algal system in the Baltic Sea, its potential decline under global <span class="hlt">warming</span> implies a loss of key functions and services such as provision of nutrient storage, substrate, food, shelter, and nursery grounds for a diverse community of marine invertebrates and fish in Baltic Sea coastal waters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26147223','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26147223"><span>Effects of <span class="hlt">Warming</span> on CO2 Fluxes in an Alpine Meadow Ecosystem on the Central Qinghai-Tibetan Plateau.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ganjurjav, Hasbagan; Gao, Qingzhu; Zhang, Weina; Liang, Yan; Li, Yawei; Cao, Xujuan; Wan, Yunfan; Li, Yue; Danjiu, Luobu</p> <p>2015-01-01</p> <p>To analyze CO2 fluxes under conditions of climate change in an alpine meadow on the central Qinghai-Tibetan Plateau, we simulated the effect of <span class="hlt">warming</span> using open top chambers (OTCs) from 2012 to 2014. The OTCs increased soil temperature by 1.62°C (P < 0.05), but decreased soil moisture (1.38%, P < 0.05) during the experiments. The response of ecosystem CO2 fluxes to <span class="hlt">warming</span> was variable, and dependent on the year. Under conditions of <span class="hlt">warming</span>, mean gross ecosystem productivity (GEP) during the growing <span class="hlt">season</span> increased significantly in 2012 and 2014 (P < 0.05); however, ecosystem respiration (ER) increased substantially only in 2012 (P < 0.05). The net ecosystem CO2 exchange (NEE) increased marginally in 2012 (P = 0.056), did not change in 2013(P > 0.05), and increased significantly in 2014 (P = 0.034) under conditions of <span class="hlt">warming</span>. The GEP was more sensitive to climate variations than was the ER, resulting in a large increase in net carbon uptake under <span class="hlt">warming</span> in the alpine meadow. Under <span class="hlt">warming</span>, the 3-year averages of GEP, ER, and NEE increased by 19.6%, 15.1%, and 21.1%, respectively. The <span class="hlt">seasonal</span> dynamic patterns of GEP and NEE, but not ER, were significantly impacted by <span class="hlt">warming</span>. Aboveground biomass, particularly the graminoid biomass increased significantly under conditions of <span class="hlt">warming</span>. Soil moisture, soil temperature, and aboveground biomass were the main factors that affected the variation of the ecosystem CO2 fluxes. The effect of <span class="hlt">warming</span> on inter- and intra-annual patterns of ecosystem CO2 fluxes and the mechanism of different sensitivities in GEP and ER to <span class="hlt">warming</span>, require further researched.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4492951','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4492951"><span>Effects of <span class="hlt">Warming</span> on CO2 Fluxes in an Alpine Meadow Ecosystem on the Central Qinghai–Tibetan Plateau</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ganjurjav, Hasbagan; Gao, Qingzhu; Zhang, Weina; Liang, Yan; Li, Yawei; Cao, Xujuan; Wan, Yunfan; Li, Yue; Danjiu, Luobu</p> <p>2015-01-01</p> <p>To analyze CO2 fluxes under conditions of climate change in an alpine meadow on the central Qinghai–Tibetan Plateau, we simulated the effect of <span class="hlt">warming</span> using open top chambers (OTCs) from 2012 to 2014. The OTCs increased soil temperature by 1.62°C (P < 0.05), but decreased soil moisture (1.38%, P < 0.05) during the experiments. The response of ecosystem CO2 fluxes to <span class="hlt">warming</span> was variable, and dependent on the year. Under conditions of <span class="hlt">warming</span>, mean gross ecosystem productivity (GEP) during the growing <span class="hlt">season</span> increased significantly in 2012 and 2014 (P < 0.05); however, ecosystem respiration (ER) increased substantially only in 2012 (P < 0.05). The net ecosystem CO2 exchange (NEE) increased marginally in 2012 (P = 0.056), did not change in 2013(P > 0.05), and increased significantly in 2014 (P = 0.034) under conditions of <span class="hlt">warming</span>. The GEP was more sensitive to climate variations than was the ER, resulting in a large increase in net carbon uptake under <span class="hlt">warming</span> in the alpine meadow. Under <span class="hlt">warming</span>, the 3-year averages of GEP, ER, and NEE increased by 19.6%, 15.1%, and 21.1%, respectively. The <span class="hlt">seasonal</span> dynamic patterns of GEP and NEE, but not ER, were significantly impacted by <span class="hlt">warming</span>. Aboveground biomass, particularly the graminoid biomass increased significantly under conditions of <span class="hlt">warming</span>. Soil moisture, soil temperature, and aboveground biomass were the main factors that affected the variation of the ecosystem CO2 fluxes. The effect of <span class="hlt">warming</span> on inter- and intra-annual patterns of ecosystem CO2 fluxes and the mechanism of different sensitivities in GEP and ER to <span class="hlt">warming</span>, require further researched. PMID:26147223</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1912675S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1912675S"><span><span class="hlt">Monthly</span> streamflow forecasting in the Rhine basin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schick, Simon; Rössler, Ole; Weingartner, Rolf</p> <p>2017-04-01</p> <p>Forecasting <span class="hlt">seasonal</span> streamflow of the Rhine river is of societal relevance as the Rhine is an important water way and water resource in Western Europe. The present study investigates the predictability of <span class="hlt">monthly</span> mean streamflow at lead times of zero, one, and two <span class="hlt">months</span> with the focus on potential benefits by the integration of <span class="hlt">seasonal</span> climate predictions. Specifically, we use <span class="hlt">seasonal</span> predictions of precipitation and surface air temperature released by the European Centre for Medium-Range Weather Forecasts (ECMWF) for a regression analysis. In order to disentangle forecast uncertainty, the 'Reverse Ensemble Streamflow Prediction' framework is adapted here to the context of regression: By using appropriate subsets of predictors the regression model is constrained to either the initial conditions, the meteorological forcing, or both. An operational application is mimicked by equipping the model with the <span class="hlt">seasonal</span> climate predictions provided by ECMWF. Finally, to mitigate the spatial aggregation of the meteorological fields the model is also applied at the subcatchment scale, and the resulting predictions are combined afterwards. The hindcast experiment is carried out for the period 1982-2011 in cross validation mode at two gauging stations, namely the Rhine at Lobith and Basel. The results show that <span class="hlt">monthly</span> forecasts are skillful with respect to climatology only at zero lead time. In addition, at zero lead time the integration of <span class="hlt">seasonal</span> climate predictions decreases the mean absolute error by 5 to 10 percentage compared to forecasts which are solely based on initial conditions. This reduction most likely is induced by the <span class="hlt">seasonal</span> prediction of precipitation and not air temperature. The study is completed by bench marking the regression model with runoff simulations from ECMWFs <span class="hlt">seasonal</span> forecast system. By simply using basin averages followed by a linear bias correction, these runoff simulations translate well to <span class="hlt">monthly</span> streamflow. Though the regression model</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3818597','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3818597"><span>Distribution, <span class="hlt">seasonal</span> variation & dengue transmission prediction in Sisaket, Thailand</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wongkoon, S.; Jaroensutasinee, M.; Jaroensutasinee, K.</p> <p>2013-01-01</p> <p>Background & objectives: Environmental factors including weather variables may play a significant role in the transmission of dengue. This study investigated the effect of <span class="hlt">seasonal</span> variation on the abundance of Aedes aegypti and Ae. albopictus larvae and explored the impact of weather variability on dengue transmission in Sisaket, Thailand. Methods: The <span class="hlt">monthly</span> mosquito larval surveys were carried out in urban and rural areas in Sisaket, Thailand from January to December 2010. Data on <span class="hlt">monthly</span>-reported cases of dengue fever over the period 2004-2010 were obtained from the Ministry of Public Health. Weather data over the same period were obtained from the Thai Meteorological Department. Chi-square test was used to find the differences relating to <span class="hlt">seasonal</span> variability, areas of study, and mosquito species factors using entomological survey data. Time series Poisson regression analysis was performed using data on <span class="hlt">monthly</span> weather variables and dengue cases. Results: There were more Ae. aegypti larvae per household than Ae. albopictus larvae in the winter and rainy <span class="hlt">seasons</span>. More Aedes larvae per household were found in the rainy <span class="hlt">season</span> than in the winter and summer <span class="hlt">seasons</span>. Relative humidity at a lag of one <span class="hlt">month</span> and rainy days in the current <span class="hlt">month</span> were significant predictors of dengue incidence in Sisaket. Interpretation & conclusions: Increased rain during the current <span class="hlt">month</span> and less humidity during the previous <span class="hlt">month</span> might trigger a higher incidence of dengue epidemic in Sisaket. The present findings suggest that the dengue incidence corresponds with the number of Aedes larvae. The <span class="hlt">seasonal</span> patterns of dengue outbreaks coincide with the rainy <span class="hlt">season</span>. PMID:24135179</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.B44D..06G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.B44D..06G"><span>Effects of experimental <span class="hlt">warming</span> and elevated CO2 on surface methane and CO­2 fluxes from a boreal black spruce peatland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gill, A. L.; Finzi, A.; Hsieh, I. F.; Giasson, M. A.</p> <p>2016-12-01</p> <p>High latitude peatlands represent a major terrestrial carbon store sensitive to climate change, as well as a globally significant methane source. While elevated atmospheric carbon dioxide concentrations and <span class="hlt">warming</span> temperatures may increase peat respiration and C losses to the atmosphere, reductions in peatland water tables associated with increased growing <span class="hlt">season</span> evapotranspiration may alter the nature of trace gas emission and increase peat C losses as CO2 relative to methane (CH4). As CH4 is a greenhouse gas with twenty times the <span class="hlt">warming</span> potential of CO2, it is critical to understand how surface fluxes of CO2 and CH4 will be influenced by factors associated with global climate change. We used automated soil respiration chambers to assess the influence of elevated atmospheric CO2 and whole ecosystem <span class="hlt">warming</span> on peatland CH4 and CO2 fluxes at the SPRUCE (Spruce and Peatland Responses Under Climatic and Environmental Change) Experiment in northern Minnesota. Here we report soil iCO2 and iCH4 flux responses to the first year of belowground <span class="hlt">warming</span> and the first <span class="hlt">season</span> of whole ecosystem <span class="hlt">warming</span> and elevated CO2 treatments. We find that peat methane fluxes are more sensitive to <span class="hlt">warming</span> treatments than peat CO2 fluxes, particularly in hollow peat microforms. Surface CO2:CH4 flux ratios decreased across <span class="hlt">warming</span> treatments, suggesting that the temperature sensitivity of methane production overshadows the effect of peat drying and surface aeration in the short term. δ13C of the emitted methane was more depleted in the early and late growing <span class="hlt">season</span>, indicating a transition from hydrogenotrophic to acetoclastic methanogenesis during periods of high photosynthetic input. The measurement record demonstrates that belowground <span class="hlt">warming</span> has measureable impacts on the nature of peat greenhouse gas emission within one year of treatment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19141198','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19141198"><span>[The innovation of <span class="hlt">warm</span> disease theory in the Ming Dynasty before Wen yi lun On Pestilence].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Zhi-bin</p> <p>2008-10-01</p> <p>Some doctors of the Ming dynasty raised subversive doubts against the traditional viewpoints of "exogenous cold disease is <span class="hlt">warm</span>-heat" before the emergence of Wen yi lun (On Pestilence), holding that <span class="hlt">warm</span>-heat disease "is contracted in different <span class="hlt">seasons</span> instead of being transformed from cold to <span class="hlt">warm</span> and/or heat". The conception of the separation of <span class="hlt">warm</span>-heat disease and exogenous cold disease had changed from obscure to clear. As the idea became clear, the recognition on the new affection of <span class="hlt">warm</span>, heat, summer-heat, pestilent pathogen was formed, and the idea that the pathogens of summer-heat and <span class="hlt">warm</span> entered the human body through the mouth and nostrils was put forward. The six-channel syndrome differentiation of <span class="hlt">warm</span> disease and the five sweat-resolving methods in pestilence raised by the doctors of this period are the aspects of the differential diagnosis of syndrome and treatment in <span class="hlt">warm</span> diseases, and deserve to be paid attention to.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28292961','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28292961"><span>Modeling <span class="hlt">month-season</span> of birth as a risk factor in mouse models of chronic disease: from multiple sclerosis to autoimmune encephalomyelitis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Reynolds, Jacob D; Case, Laure K; Krementsov, Dimitry N; Raza, Abbas; Bartiss, Rose; Teuscher, Cory</p> <p>2017-06-01</p> <p><span class="hlt">Month-season</span> of birth (M-SOB) is a risk factor in multiple chronic diseases, including multiple sclerosis (MS), where the lowest and greatest risk of developing MS coincide with the lowest and highest birth rates, respectively. To determine whether M-SOB effects in such chronic diseases as MS can be experimentally modeled, we examined the effect of M-SOB on susceptibility of C57BL/6J mice to experimental autoimmune encephalomyelitis (EAE). As in MS, mice that were born during the M-SOB with the lowest birth rate were less susceptible to EAE than mice born during the M-SOB with the highest birth rate. We also show that the M-SOB effect on EAE susceptibility is associated with differential production of multiple cytokines/chemokines by neuroantigen-specific T cells that are known to play a role in EAE pathogenesis. Taken together, these results support the existence of an M-SOB effect that may reflect <span class="hlt">seasonally</span> dependent developmental differences in adaptive immune responses to self-antigens independent of external stimuli, including exposure to sunlight and vitamin D. Moreover, our documentation of an M-SOB effect on EAE susceptibility in mice allows for modeling and detailed analysis of mechanisms that underlie the M-SOB effect in not only MS but in numerous other diseases in which M-SOB impacts susceptibility.-Reynolds, J. D., Case, L. K., Krementsov, D. N., Raza, A., Bartiss, R., Teuscher, C. Modeling <span class="hlt">month-season</span> of birth as a risk factor in mouse models of chronic disease: from multiple sclerosis to autoimmune encephalomyelitis. © FASEB.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15229669','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15229669"><span>[Treatment of patients with neuromuscular disease in a <span class="hlt">warm</span> climate].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dahl, Arve; Skjeldal, Ola H; Simensen, Andreas; Dalen, Håkon E; Bråthen, Tone; Ahlvin, Petra; Svendsby, Ellen Kathrine; Sveinall, Anne; Fredriksen, Per Morten</p> <p>2004-07-01</p> <p>Several patient groups request treatment in a <span class="hlt">warm</span> climate, in spite of the fact that the effects of such treatment are undocumented. 47 children and 40 adults with neuromuscular diseases were recruited, stratified according to sex, use or non-use of electric wheelchair, primary myopathy or hereditary neuropathy, and randomised into two adult and two children groups. The patients were treated in a rehabilitation centre, either on Lanzarote or in Norway. All patients were monitored with physical tests and questionnaires at the start of the study, at the end of the treatment period, after three <span class="hlt">months</span> (all groups) and after six <span class="hlt">months</span> (adults only). No significant differences in effect between the groups were found. In the <span class="hlt">warm</span> climate, the adult patient group showed a statistically significant improvement regarding pain, quality of life, depression, and results of physical tests at the end of treatment. After three <span class="hlt">months</span>, the improvement in physical tests was still present. Among adult patients treated in Norway, improvement in physical tests was statistically significant after three <span class="hlt">months</span>, but not at the end of the treatment period. This study did not show a statistically significant difference between patients with various neuromuscular diseases treated in a <span class="hlt">warm</span> climate compared to similar patients treated in Norway.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013NatCC...3..563D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013NatCC...3..563D"><span>Reductions in labour capacity from heat stress under climate <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dunne, John P.; Stouffer, Ronald J.; John, Jasmin G.</p> <p>2013-06-01</p> <p>A fundamental aspect of greenhouse-gas-induced <span class="hlt">warming</span> is a global-scale increase in absolute humidity. Under continued <span class="hlt">warming</span>, this response has been shown to pose increasingly severe limitations on human activity in tropical and mid-latitudes during peak <span class="hlt">months</span> of heat stress. One heat-stress metric with broad occupational health applications is wet-bulb globe temperature. We combine wet-bulb globe temperatures from global climate historical reanalysis and Earth System Model (ESM2M) projections with industrial and military guidelines for an acclimated individual's occupational capacity to safely perform sustained labour under environmental heat stress (labour capacity)--here defined as a global population-weighted metric temporally fixed at the 2010 distribution. We estimate that environmental heat stress has reduced labour capacity to 90% in peak <span class="hlt">months</span> over the past few decades. ESM2M projects labour capacity reduction to 80% in peak <span class="hlt">months</span> by 2050. Under the highest scenario considered (Representative Concentration Pathway 8.5), ESM2M projects labour capacity reduction to less than 40% by 2200 in peak <span class="hlt">months</span>, with most tropical and mid-latitudes experiencing extreme climatological heat stress. Uncertainties and caveats associated with these projections include climate sensitivity, climate <span class="hlt">warming</span> patterns, CO2 emissions, future population distributions, and technological and societal change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013HESSD..10.8365T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013HESSD..10.8365T"><span>Coupled prediction of flood response and debris flow initiation during <span class="hlt">warm</span> and cold <span class="hlt">season</span> events in the Southern Appalachians, USA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tao, J.; Barros, A. P.</p> <p>2013-07-01</p> <p>Debris flows associated with rainstorms are a frequent and devastating hazard in the Southern Appalachians in the United States. Whereas <span class="hlt">warm</span> <span class="hlt">season</span> events are clearly associated with heavy rainfall intensity, the same cannot be said for the cold <span class="hlt">season</span> events. Instead, there is a relationship between large (cumulative) rainfall events independently of <span class="hlt">season</span>, and thus hydrometeorological regime, and debris flows. This suggests that the dynamics of subsurface hydrologic processes play an important role as a trigger mechanism, specifically through soil moisture redistribution by interflow. The first objective of this study is to investigate this hypothesis. The second objective is to assess the physical basis for a regional coupled flood prediction and debris flow warning system. For this purpose, uncalibrated model simulations of well-documented debris flows in headwater catchments of the Southern Appalachians using a 3-D surface-groundwater hydrologic model coupled with slope stability models are examined in detail. Specifically, we focus on two vulnerable headwater catchments that experience frequent debris flows, the Big Creek and the Jonathan Creek in the Upper Pigeon River Basin, North Carolina, and three distinct weather systems: an extremely heavy summertime convective storm in 2011; a persistent winter storm lasting several days; and a severe winter storm in 2009. These events were selected due to the optimal availability of rainfall observations, availability of detailed field surveys of the landslides shortly after they occurred, which can be used to evaluate model predictions, and because they are representative of events that cause major economic losses in the region. The model results substantiate that interflow is a useful prognostic of conditions necessary for the initiation of slope instability, and should therefore be considered explicitly in landslide hazard assessments. Moreover, the relationships between slope stability and interflow are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMED51C0816I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMED51C0816I"><span>Global <span class="hlt">warming</span> /climate change: Involving students using local example.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Isiorho, S. A.</p> <p>2016-12-01</p> <p>The current political climate has made it apparent that the general public does not believe in global <span class="hlt">warming</span>. Also, there appears to be some confusion between global <span class="hlt">warming</span> and climate change; global <span class="hlt">warming</span> is one aspect of climate change. Most scientists believe there is climate change and global <span class="hlt">warming</span>, although, there is still doubt among students on global <span class="hlt">warming</span>. Some upper level undergraduate students are required to conduct water level/temperature measurements as part of their course grade. In addition to students having their individual projects, the various classes also utilize a well field within a wetland on campus to conduct group projects. Twelve wells in the well field on campus are used regularly by students to measure the depth of groundwater, the temperature of the waters and other basic water chemistry parameters like pH, conductivity and total dissolved solid (TDS) as part of the class group project. The data collected by each class is added to data from previous classes. Students work together as a group to interpret the data. More than 100 students have participated in this venture for more than 10 years of the four upper level courses: hydrogeology, environmental and urban geology, environmental conservation and wetlands. The temperature trend shows the <span class="hlt">seasonal</span> variation as one would expect, but it also shows an upward trend (<span class="hlt">warming</span>). These data demonstrate a change in climate and <span class="hlt">warming</span>. Thus, the students participated in data collection, learn to write report and present their result to their peers in the classrooms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMPP43D..02F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMPP43D..02F"><span>Last interglacial temperature <span class="hlt">seasonality</span> reconstructed from tropical Atlantic corals</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Felis, T.; Brocas, W.; Obert, J. C.; Gierz, P.; Lohmann, G.; Scholz, D.; Kölling, M.; Pfeiffer, M.; Scheffers, S. R.</p> <p>2016-12-01</p> <p>Reconstructions of last interglacial ( 127-117 ka) climate offer insights into the natural response and variability of the climate system during a period partially analogous to future climate change scenarios. However, the <span class="hlt">seasonal</span> temperature changes of the tropical ocean are not well known for the last interglacial period. Here we present well preserved fossil corals (Diploria strigosa) recovered from the southern Caribbean island of Bonaire. These corals have been precisely dated by the 230Th/U-method to between 130 and 118 ka ago. Annual banding of the coral skeleton enabled construction of time windows of <span class="hlt">monthly</span> resolved Sr/Ca temperature proxy records. Our eight coral records of up to 37 years in length cover a total of 105 years within the last interglacial period. From these coral records, sea surface temperature (SST) <span class="hlt">seasonality</span> in the tropical North Atlantic Ocean is reconstructed. We detect similar to modern SST <span class="hlt">seasonality</span> of 2.9 °C during the early (130 ka) and the late last interglacial (120 - 118 ka). However, within the mid-last interglacial, a significantly higher than modern SST <span class="hlt">seasonality</span> of 4.9 °C (at 126 ka) and 4.1 °C (at 124 ka) is observed. These findings are supported by climate model simulations (COSMOS) and are consistent with the evolving amplitude of orbitally induced changes in <span class="hlt">seasonality</span> of insolation throughout the last interglacial, irrespective of wider climatic instabilities that characterised this period, e.g. at 118 ka ago. The climate model simulations suggest that the SST <span class="hlt">seasonality</span> changes documented in our last interglacial coral Sr/Ca records are representative of larger regions within the tropical North Atlantic. These simulations also suggest that the reconstructed SST <span class="hlt">seasonality</span> increase during the mid-last interglacial is caused primarily by summer <span class="hlt">warming</span>. Furthermore, a 124 ka old coral documents evidence of decadal SST variability in the tropical North Atlantic during the last interglacial, akin to that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3832027','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3832027"><span>Microclimate moderates plant responses to macroclimate <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>De Frenne, Pieter; Rodríguez-Sánchez, Francisco; Coomes, David Anthony; Baeten, Lander; Verstraeten, Gorik; Vellend, Mark; Bernhardt-Römermann, Markus; Brown, Carissa D.; Brunet, Jörg; Cornelis, Johnny; Decocq, Guillaume M.; Dierschke, Hartmut; Eriksson, Ove; Gilliam, Frank S.; Hédl, Radim; Heinken, Thilo; Hermy, Martin; Hommel, Patrick; Jenkins, Michael A.; Kelly, Daniel L.; Kirby, Keith J.; Mitchell, Fraser J. G.; Naaf, Tobias; Newman, Miles; Peterken, George; Petřík, Petr; Schultz, Jan; Sonnier, Grégory; Van Calster, Hans; Waller, Donald M.; Walther, Gian-Reto; White, Peter S.; Woods, Kerry D.; Wulf, Monika; Graae, Bente Jessen; Verheyen, Kris</p> <p>2013-01-01</p> <p>Recent global <span class="hlt">warming</span> is acting across marine, freshwater, and terrestrial ecosystems to favor species adapted to warmer conditions and/or reduce the abundance of cold-adapted organisms (i.e., “thermophilization” of communities). Lack of community responses to increased temperature, however, has also been reported for several taxa and regions, suggesting that “climatic lags” may be frequent. Here we show that microclimatic effects brought about by forest canopy closure can buffer biotic responses to macroclimate <span class="hlt">warming</span>, thus explaining an apparent climatic lag. Using data from 1,409 vegetation plots in European and North American temperate forests, each surveyed at least twice over an interval of 12–67 y, we document significant thermophilization of ground-layer plant communities. These changes reflect concurrent declines in species adapted to cooler conditions and increases in species adapted to warmer conditions. However, thermophilization, particularly the increase of <span class="hlt">warm</span>-adapted species, is attenuated in forests whose canopies have become denser, probably reflecting cooler growing-<span class="hlt">season</span> ground temperatures via increased shading. As standing stocks of trees have increased in many temperate forests in recent decades, local microclimatic effects may commonly be moderating the impacts of macroclimate <span class="hlt">warming</span> on forest understories. Conversely, increases in harvesting woody biomass—e.g., for bioenergy—may open forest canopies and accelerate thermophilization of temperate forest biodiversity. PMID:24167287</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018HESS...22.2057A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018HESS...22.2057A"><span>Skilful <span class="hlt">seasonal</span> forecasts of streamflow over Europe?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arnal, Louise; Cloke, Hannah L.; Stephens, Elisabeth; Wetterhall, Fredrik; Prudhomme, Christel; Neumann, Jessica; Krzeminski, Blazej; Pappenberger, Florian</p> <p>2018-04-01</p> <p>This paper considers whether there is any added value in using <span class="hlt">seasonal</span> climate forecasts instead of historical meteorological observations for forecasting streamflow on <span class="hlt">seasonal</span> timescales over Europe. A Europe-wide analysis of the skill of the newly operational EFAS (European Flood Awareness System) <span class="hlt">seasonal</span> streamflow forecasts (produced by forcing the Lisflood model with the ECMWF System 4 <span class="hlt">seasonal</span> climate forecasts), benchmarked against the ensemble streamflow prediction (ESP) forecasting approach (produced by forcing the Lisflood model with historical meteorological observations), is undertaken. The results suggest that, on average, the System 4 <span class="hlt">seasonal</span> climate forecasts improve the streamflow predictability over historical meteorological observations for the first <span class="hlt">month</span> of lead time only (in terms of hindcast accuracy, sharpness and overall performance). However, the predictability varies in space and time and is greater in winter and autumn. Parts of Europe additionally exhibit a longer predictability, up to 7 <span class="hlt">months</span> of lead time, for certain <span class="hlt">months</span> within a <span class="hlt">season</span>. In terms of hindcast reliability, the EFAS <span class="hlt">seasonal</span> streamflow hindcasts are on average less skilful than the ESP for all lead times. The results also highlight the potential usefulness of the EFAS <span class="hlt">seasonal</span> streamflow forecasts for decision-making (measured in terms of the hindcast discrimination for the lower and upper terciles of the simulated streamflow). Although the ESP is the most potentially useful forecasting approach in Europe, the EFAS <span class="hlt">seasonal</span> streamflow forecasts appear more potentially useful than the ESP in some regions and for certain <span class="hlt">seasons</span>, especially in winter for almost 40 % of Europe. Patterns in the EFAS <span class="hlt">seasonal</span> streamflow hindcast skill are however not mirrored in the System 4 <span class="hlt">seasonal</span> climate hindcasts, hinting at the need for a better understanding of the link between hydrological and meteorological variables on <span class="hlt">seasonal</span> timescales, with the aim of improving climate</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" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4169446','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4169446"><span>Effects of <span class="hlt">Warming</span> on Chlorophyll Degradation and Carbohydrate Accumulation of Alpine Herbaceous Species during Plant Senescence on the Tibetan Plateau</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Shi, Changguang; Sun, Geng; Zhang, Hongxuan; Xiao, Bingxue; Ze, Bai; Zhang, Nannan; Wu, Ning</p> <p>2014-01-01</p> <p>Plant senescence is a critical life history process accompanied by chlorophyll degradation and has large implications for nutrient resorption and carbohydrate storage. Although photoperiod governs much of <span class="hlt">seasonal</span> leaf senescence in many plant species, temperature has also been shown to modulate this process. Therefore, we hypothesized that climate <span class="hlt">warming</span> would significantly impact the length of the plant growing <span class="hlt">season</span> and ultimate productivity. To test this assumption, we measured the effects of simulated autumn climate <span class="hlt">warming</span> paradigms on four native herbaceous species that represent distinct life forms of alpine meadow plants on the Tibetan Plateau. Conditions were simulated in open-top chambers (OTCs) and the effects on the degradation of chlorophyll, nitrogen (N) concentration in leaves and culms, total non-structural carbohydrate (TNC) in roots, growth and phenology were assessed during one year following treatment. The results showed that climate <span class="hlt">warming</span> in autumn changed the senescence process only for perennials by slowing chlorophyll degradation at the beginning of senescence and accelerating it in the following phases. <span class="hlt">Warming</span> also increased root TNC storage as a result of higher N concentrations retained in leaves; however, this effect was species dependent and did not alter the growing and flowering phenology in the following <span class="hlt">seasons</span>. Our results indicated that autumn <span class="hlt">warming</span> increases carbohydrate accumulation, not only by enhancing activities of photosynthetic enzymes (a mechanism proposed in previous studies), but also by affecting chlorophyll degradation and preferential allocation of resources to different plant compartments. The different responses to <span class="hlt">warming</span> can be explained by inherently different growth and phenology patterns observed among the studied species. The results implied that <span class="hlt">warming</span> leads to changes in the competitive balance among life forms, an effect that can subsequently shift vegetation distribution and species composition</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4278364','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4278364"><span>Maternal <span class="hlt">Warm</span> Responsiveness and Negativity Following Traumatic Brain Injury in Young Children</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fairbanks, Joy M.; Brown, Tanya M.; Cassedy, Amy; Taylor, H. Gerry; Yeates, Keith O.; Wade, Shari L.</p> <p>2014-01-01</p> <p>Purpose/Objective To understand how traumatic brain injury (TBI) affects maternal <span class="hlt">warm</span> responsiveness and negativity over the first 12 <span class="hlt">months</span> following injury. Method/Design We used a concurrent cohort research design to examine dyadic interactions in young children with a TBI (n = 78) and a comparison group of young children with orthopedic injuries (OI; n = 112) and their families during the initial weeks following injury (i.e., baseline) and at two follow-up periods (approximately 6 and 12 <span class="hlt">months</span> later). Trained raters coded videotaped interactions during a free play and structured teaching task for maternal <span class="hlt">warm</span> responsiveness and negativity. Results Mothers in the complicated mild/moderate TBI group, but not those in the severe TBI group, exhibited significantly lower levels of maternal <span class="hlt">warm</span> responsiveness than mothers in the OI group. However, these differences were observed only at baseline during free play and only at baseline and 6 <span class="hlt">months</span> postinjury during the structured teaching task, suggesting diminishing adverse effects of complicated mild/moderate TBI on parenting over time postinjury. Analysis failed to reveal group differences in maternal negativity at any of the assessments. Across groups, lower socioeconomic status (SES) was associated with lower levels of <span class="hlt">warm</span> responsiveness and higher levels of negativity. Conclusions/Implications These findings, though preliminary, indicate possible alterations in mother–child interactions in the <span class="hlt">months</span> following a TBI. PMID:23978080</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020080866','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020080866"><span>On the Regulation of the Pacific <span class="hlt">Warm</span> Pool Temperature</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chou, Ming-Dah; Chou, Sue-Hsien; Chan, Pui-King; Lau, William K. M. (Technical Monitor)</p> <p>2002-01-01</p> <p>In the tropical western Pacific, regions of the highest sea surface temperature (SST) and the largest cloud cover are found to have the largest surface heating, primarily due to the weak evaporative cooling associated with weak winds. This situation is in variance with the suggestions that the temperature in the Pacific <span class="hlt">warm</span> pool is regulated either by the reduced solar heating due to an enhanced cloudiness or by the enhanced evaporative cooling due to an elevated SST. It is clear that an enhanced surface heating in an enhanced convection region is not sustainable and must be interrupted by variations in large-scale atmospheric circulation. As the deep convective regions shift away from regions of high SST due primarily to <span class="hlt">seasonal</span> variation and secondarily to interannual variation of the large-scale atmospheric and oceanic circulation, both trade wind and evaporative cooling in the high SST region increase, leading to a reduction in SST. We conclude that the evaporative cooling associated with the <span class="hlt">seasonal</span> and interannual variations of trade winds in the primary factor that prevent the <span class="hlt">warm</span> pool SST from increasing to a value much higher than what is observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018GPC...162..136B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018GPC...162..136B"><span><span class="hlt">Seasonal</span> and elevational contrasts in temperature trends in Central Chile between 1979 and 2015</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burger, F.; Brock, B.; Montecinos, A.</p> <p>2018-03-01</p> <p>We analyze trends in temperature from 18 temperature stations and one upper air sounding site at 30°-35° S in central Chile between 1979-2015, to explore geographical and <span class="hlt">season</span> temperature trends and their controls, using regional ocean-atmosphere indices. Significant <span class="hlt">warming</span> trends are widespread at inland stations, while trends are non-significant or negative at coastal sites, as found in previous studies. However, ubiquitous <span class="hlt">warming</span> across the region in the past 8 years, suggests the recent period of coastal cooling has ended. Significant <span class="hlt">warming</span> trends are largely restricted to austral spring, summer and autumn <span class="hlt">seasons</span>, with very few significant positive or negative trends in winter identified. Autumn <span class="hlt">warming</span> is notably strong in the Andes, which, together with significant <span class="hlt">warming</span> in spring, could help to explain the negative mass balance of snow and glaciers in the region. A strong Pacific maritime influence on regional temperature trends is inferred through correlation with the Interdecadal Pacific Oscillation (IPO) index and coastal sea surface temperature, but the strength of this influence rapidly diminishes inland, and the majority of valley, and all Andes, sites are independent of the IPO index. Instead, valley and Andes sites, and mid-troposphere temperature in the coastal radiosonde profile, show correlation with the autumn Antarctic Oscillation which, in its current positive phase, promotes subsidence and <span class="hlt">warming</span> at the latitude of central Chile.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatGe...9..669K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatGe...9..669K"><span>The tropical Pacific as a key pacemaker of the variable rates of global <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kosaka, Yu; Xie, Shang-Ping</p> <p>2016-09-01</p> <p>Global mean surface temperature change over the past 120 years resembles a rising staircase: the overall <span class="hlt">warming</span> trend was interrupted by the mid-twentieth-century big hiatus and the <span class="hlt">warming</span> slowdown since about 1998. The Interdecadal Pacific Oscillation has been implicated in modulations of global mean surface temperatures, but which part of the mode drives the variability in <span class="hlt">warming</span> rates is unclear. Here we present a successful simulation of the global <span class="hlt">warming</span> staircase since 1900 with a global ocean-atmosphere coupled model where tropical Pacific sea surface temperatures are forced to follow the observed evolution. Without prescribed tropical Pacific variability, the same model, on average, produces a continual <span class="hlt">warming</span> trend that accelerates after the 1960s. We identify four events where the tropical Pacific decadal cooling markedly slowed down the <span class="hlt">warming</span> trend. Matching the observed spatial and <span class="hlt">seasonal</span> fingerprints we identify the tropical Pacific as a key pacemaker of the <span class="hlt">warming</span> staircase, with radiative forcing driving the overall <span class="hlt">warming</span> trend. Specifically, tropical Pacific variability amplifies the first <span class="hlt">warming</span> epoch of the 1910s-1940s and determines the timing when the big hiatus starts and ends. Our method of removing internal variability from the observed record can be used for real-time monitoring of anthropogenic <span class="hlt">warming</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018E%26ES..107a2028G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018E%26ES..107a2028G"><span>Water runoff vs modern climatic <span class="hlt">warming</span> in mountainous cryolithic zone in North-East Russia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Glotov, V. E.; Glotova, L. P.</p> <p>2018-01-01</p> <p>The article presents the results of studying the effects of current climatic <span class="hlt">warming</span> for both surface and subsurface water runoffs in North-East Russia, where the Main Watershed of the Earth separates it into the Arctic and Pacific continental slopes. The process of climatic <span class="hlt">warming</span> is testified by continuous weather records during 80-100 years and longer periods. Over the Arctic slope and in the northern areas of the Pacific slope, climatic <span class="hlt">warming</span> results in a decline in a total runoff of rivers whereas the ground-water recharge becomes greater in winter low-level conditions. In the southern Pacific slope and in the Sea of Okhotsk basin, the effect of climatic <span class="hlt">warming</span> is an overall increase in total runoff including its subsurface constituents. We believe these peculiar characters of river runoff there to be related to the cryolithic zone environments. Over the Arctic slope and the northern Pacific slope, where cryolithic zone is continuous, the total runoff has its subsurface constituent as basically resulting from discharge of ground waters hosted in <span class="hlt">seasonally</span> thawing rocks. Warmer climatic conditions favor growth of vegetation that needs more water for the processes of evapotranspiration and evaporation from rocky surfaces in summer <span class="hlt">seasons</span>. In the Sea of Okhotsk basin, where the cryolithic zone is discontinuous, not only ground waters in <span class="hlt">seasonally</span> thawing layers, but also continuous taliks and subpermafrost waters participate in processes of river recharges. As a result, a greater biological productivity of vegetation cover does not have any effect on ground-water supply and river recharge processes. If a steady climate <span class="hlt">warming</span> is provided, a continuous cryolithic zone can presumably degrade into a discontinuous and then into an island-type permafrost layer. Under such a scenario, there will be a general increase in the total runoff and its subsurface constituent. From geoecological viewpoints, a greater runoff will have quite positive effects, whereas some</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060035752&hterms=Global+warming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DGlobal%2Bwarming','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060035752&hterms=Global+warming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DGlobal%2Bwarming"><span>Optimal Detection of Global <span class="hlt">Warming</span> using Temperature Profiles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Leroy, Stephen S.</p> <p>1997-01-01</p> <p>Optimal fingerprinting is applied to estimate the amount of time it would take to detect <span class="hlt">warming</span> by increased concentrations of carbon dioxide in <span class="hlt">monthly</span> averages of temperature profiles over the Indian Ocean.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27836844','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27836844"><span><span class="hlt">Season</span>-Specific Occurrence of Potentially Pathogenic Vibrio spp. on the Southern Coast of South Korea.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Di, Doris Y W; Lee, Anna; Jang, Jeonghwan; Han, Dukki; Hur, Hor-Gil</p> <p>2017-02-01</p> <p>Vibrio species are widely distributed in <span class="hlt">warm</span> estuarine and coastal environments, and they can infect humans through the consumption of raw and mishandled contaminated seafood. In this study, we aimed to isolate and observe the distribution of enteropathogenic Vibrio spp. from environments of the southern coast of South Korea over a <span class="hlt">season</span> cycle. A total of 10,983 isolates of Vibrio spp. were obtained from tidal water and mud samples over a 1-year period from five sampling sites along the southwest coast of South Korea. We found that Vibrio alginolyticus (n = 6,262) and Vibrio parahaemolyticus (n = 1,757) were ubiquitous in both tidal water and mud year round, whereas Vibrio cholerae (n = 24) and Vibrio vulnificus (n = 130) were <span class="hlt">seasonally</span> specific to summer. While all V. cholerae isolates were nontoxigenic (non-O1 and non-O139), more than 88% of V. vulnificus isolates possessed the virulence factor elastolytic protease (encoded by vvp). Interestingly, V. parahaemolyticus, which was omnipresent in all <span class="hlt">seasons</span>, contained the virulence factors thermostable direct hemolysin (encoded by tdh) and thermostable direct hemolysin-related hemolysin (encoded by trh) in larger amounts in June (29 trh-positive strains) and September (14 tdh-, 36 trh-, and 12 tdh- and trh-positive strains) than in December (4 trh-positive strains) and February (3 tdh-positive strains), and virulence factors were absent from isolates detected in April. To understand why virulence factors were detected only in the <span class="hlt">warm</span> <span class="hlt">season</span> and were absent in the cold <span class="hlt">season</span> although the locations are static, long-term monitoring and particularly <span class="hlt">seasonal</span> study are necessary. The presence of enteropathogenic Vibrio species (Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus), which cause acute diarrheal infection, septicemia, and wound infections upon ingestion through food and water, is usually associated with temperature. The World Health Organization (WHO) has estimated that there are 1.4 to 4</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5244290','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5244290"><span><span class="hlt">Season</span>-Specific Occurrence of Potentially Pathogenic Vibrio spp. on the Southern Coast of South Korea</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Di, Doris Y. W.; Lee, Anna; Jang, Jeonghwan; Han, Dukki</p> <p>2016-01-01</p> <p>ABSTRACT Vibrio species are widely distributed in <span class="hlt">warm</span> estuarine and coastal environments, and they can infect humans through the consumption of raw and mishandled contaminated seafood. In this study, we aimed to isolate and observe the distribution of enteropathogenic Vibrio spp. from environments of the southern coast of South Korea over a <span class="hlt">season</span> cycle. A total of 10,983 isolates of Vibrio spp. were obtained from tidal water and mud samples over a 1-year period from five sampling sites along the southwest coast of South Korea. We found that Vibrio alginolyticus (n = 6,262) and Vibrio parahaemolyticus (n = 1,757) were ubiquitous in both tidal water and mud year round, whereas Vibrio cholerae (n = 24) and Vibrio vulnificus (n = 130) were <span class="hlt">seasonally</span> specific to summer. While all V. cholerae isolates were nontoxigenic (non-O1 and non-O139), more than 88% of V. vulnificus isolates possessed the virulence factor elastolytic protease (encoded by vvp). Interestingly, V. parahaemolyticus, which was omnipresent in all <span class="hlt">seasons</span>, contained the virulence factors thermostable direct hemolysin (encoded by tdh) and thermostable direct hemolysin-related hemolysin (encoded by trh) in larger amounts in June (29 trh-positive strains) and September (14 tdh-, 36 trh-, and 12 tdh- and trh-positive strains) than in December (4 trh-positive strains) and February (3 tdh-positive strains), and virulence factors were absent from isolates detected in April. To understand why virulence factors were detected only in the <span class="hlt">warm</span> <span class="hlt">season</span> and were absent in the cold <span class="hlt">season</span> although the locations are static, long-term monitoring and particularly <span class="hlt">seasonal</span> study are necessary. IMPORTANCE The presence of enteropathogenic Vibrio species (Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus), which cause acute diarrheal infection, septicemia, and wound infections upon ingestion through food and water, is usually associated with temperature. The World Health Organization (WHO) has estimated that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4820648','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4820648"><span>Soil <span class="hlt">warming</span> increased whole-tree water use of Pinus cembra at the treeline in the Central Tyrolean Alps</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wieser, Gerhard; Grams, Thorsten E.E.; Matysssek, Rainer; Oberhuber, Walter; Gruber, Andreas</p> <p>2016-01-01</p> <p>The study quantified the effect of soil <span class="hlt">warming</span> on sap flow density (Qs) of Pinus cembra at treeline in the Central Tyrolean Alps. To enhance soil temperature we installed a transparent roof construction above the forest floor around six trees. Six other trees served as controls in the absence of any manipulation. Roofing enhanced growing <span class="hlt">season</span> mean soil temperature by 1.6, 1.3, and 1.0 °C at 5, 10, and 20 cm soil depth, respectively, while soil water availability was not affected. Sap flow density (using Granier-type thermal dissipation probes) and environmental parameters were monitored throughout three growing <span class="hlt">seasons</span>. During the first year of treatment, no <span class="hlt">warming</span> effect was detected on Qs. However, soil <span class="hlt">warming</span> caused Qs to increase significantly by 11 and 19% above levels in control trees during the second and third year, respectively. This effect appeared to result from <span class="hlt">warming</span>-induced root production, a reduction in viscosity and perhaps an increase also in root hydraulic conductivity. Hardly affected were leaf-level net CO2 uptake rate and conductance for water vapor, so that water-use efficiency stayed unchanged as confirmed by needle δ13C analysis. We conclude that tree water loss will increase with soil <span class="hlt">warming</span>, which may alter the water balance within the treeline ecotone of the Central Austrian Alps in a future <span class="hlt">warming</span> environment. PMID:25737326</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoRL..44..892L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoRL..44..892L"><span>Lake <span class="hlt">seasonality</span> across the Tibetan Plateau and their varying relationship with regional mass changes and local hydrology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lei, Yanbin; Yao, Tandong; Yang, Kun; Sheng, Yongwei; Kleinherenbrink, Marcel; Yi, Shuang; Bird, Broxton W.; Zhang, Xiaowen; Zhu, La; Zhang, Guoqing</p> <p>2017-01-01</p> <p>The recent growth and deepening of inland lakes in the Tibetan Plateau (TP) may be a salient indicator of the consequences of climate change. The <span class="hlt">seasonal</span> dynamics of these lakes is poorly understood despite this being potentially crucial for disentangling contributions from glacier melt and precipitation, which are all sensitive to climate, to lake water budget. Using in situ observations, satellite altimetry and gravimetry data, we identified two patterns of lake level <span class="hlt">seasonality</span>. In the central, northern, and northeastern TP, lake levels are characterized by considerable increases during <span class="hlt">warm</span> <span class="hlt">seasons</span> and decreases during cold <span class="hlt">seasons</span>, which is consistent with regional mass changes related to monsoon precipitation and evaporation. In the northwestern TP, however, lake levels exhibit dramatic increases during both <span class="hlt">warm</span> and cold <span class="hlt">seasons</span>, which deviate from regional mass changes. This appears to be more connected with high spring snowfall and large summer glacier melt. The variable lake level response to different drivers indicates heterogeneous sensitivity to climate change between the northwestern TP and other regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27023422','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27023422"><span>Complex regional pain syndrome: evidence for <span class="hlt">warm</span> and cold subtypes in a large prospective clinical sample.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bruehl, Stephen; Maihöfner, Christian; Stanton-Hicks, Michael; Perez, Roberto S G M; Vatine, Jean-Jacques; Brunner, Florian; Birklein, Frank; Schlereth, Tanja; Mackey, Sean; Mailis-Gagnon, Angela; Livshitz, Anatoly; Harden, R Norman</p> <p>2016-08-01</p> <p>Limited research suggests that there may be <span class="hlt">Warm</span> complex regional pain syndrome (CRPS) and Cold CRPS subtypes, with inflammatory mechanisms contributing most strongly to the former. This study for the first time used an unbiased statistical pattern recognition technique to evaluate whether distinct <span class="hlt">Warm</span> vs Cold CRPS subtypes can be discerned in the clinical population. An international, multisite study was conducted using standardized procedures to evaluate signs and symptoms in 152 patients with clinical CRPS at baseline, with 3-<span class="hlt">month</span> follow-up evaluations in 112 of these patients. Two-step cluster analysis using automated cluster selection identified a 2-cluster solution as optimal. Results revealed a <span class="hlt">Warm</span> CRPS patient cluster characterized by a <span class="hlt">warm</span>, red, edematous, and sweaty extremity and a Cold CRPS patient cluster characterized by a cold, blue, and less edematous extremity. Median pain duration was significantly (P < 0.001) shorter in the <span class="hlt">Warm</span> CRPS (4.7 <span class="hlt">months</span>) than in the Cold CRPS subtype (20 <span class="hlt">months</span>), with pain intensity comparable. A derived total inflammatory score was significantly (P < 0.001) elevated in the <span class="hlt">Warm</span> CRPS group (compared with Cold CRPS) at baseline but diminished significantly (P < 0.001) over the follow-up period, whereas this score did not diminish in the Cold CRPS group (time × subtype interaction: P < 0.001). Results support the existence of a <span class="hlt">Warm</span> CRPS subtype common in patients with acute (<6 <span class="hlt">months</span>) CRPS and a relatively distinct Cold CRPS subtype most common in chronic CRPS. The pattern of clinical features suggests that inflammatory mechanisms contribute most prominently to the <span class="hlt">Warm</span> CRPS subtype but that these mechanisms diminish substantially during the first year postinjury.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28675635','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28675635"><span>Deep peat <span class="hlt">warming</span> increases surface methane and carbon dioxide emissions in a black spruce-dominated ombrotrophic bog.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gill, Allison L; Giasson, Marc-André; Yu, Rieka; Finzi, Adrien C</p> <p>2017-12-01</p> <p>Boreal peatlands contain approximately 500 Pg carbon (C) in the soil, emit globally significant quantities of methane (CH 4 ), and are highly sensitive to climate change. <span class="hlt">Warming</span> associated with global climate change is likely to increase the rate of the temperature-sensitive processes that decompose stored organic carbon and release carbon dioxide (CO 2 ) and CH 4 . Variation in the temperature sensitivity of CO 2 and CH 4 production and increased peat aerobicity due to enhanced growing-<span class="hlt">season</span> evapotranspiration may alter the nature of peatland trace gas emission. As CH 4 is a powerful greenhouse gas with 34 times the <span class="hlt">warming</span> potential of CO 2 , it is critical to understand how factors associated with global change will influence surface CO 2 and CH 4 fluxes. Here, we leverage the Spruce and Peatland Responses Under Changing Environments (SPRUCE) climate change manipulation experiment to understand the impact of a 0-9°C gradient in deep belowground <span class="hlt">warming</span> ("Deep Peat Heat", DPH) on peat surface CO 2 and CH 4 fluxes. We find that DPH treatments increased both CO 2 and CH 4 emission. Methane production was more sensitive to <span class="hlt">warming</span> than CO 2 production, decreasing the C-CO 2 :C-CH 4 of the respired carbon. Methane production is dominated by hydrogenotrophic methanogenesis but deep peat <span class="hlt">warming</span> increased the δ 13 C of CH 4 suggesting an increasing contribution of acetoclastic methanogenesis to total CH 4 production with <span class="hlt">warming</span>. Although the total quantity of C emitted from the SPRUCE Bog as CH 4 is <2%, CH 4 represents >50% of <span class="hlt">seasonal</span> C emissions in the highest-<span class="hlt">warming</span> treatments when adjusted for CO 2 equivalents on a 100-year timescale. These results suggest that <span class="hlt">warming</span> in boreal regions may increase CH 4 emissions from peatlands and result in a positive feedback to ongoing <span class="hlt">warming</span>. © 2017 John Wiley & Sons Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18409426','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18409426"><span>Phenological sequences reveal aggregate life history response to climatic <span class="hlt">warming</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Post, Eric S; Pedersen, Christian; Wilmers, Christopher C; Forchhammer, Mads C</p> <p>2008-02-01</p> <p>Climatic <span class="hlt">warming</span> is associated with organisms breeding earlier in the <span class="hlt">season</span> than is typical for their species. In some species, however, response to <span class="hlt">warming</span> is more complex than a simple advance in the timing of all life history events preceding reproduction. Disparities in the extent to which different components of the reproductive phenology of organisms vary with climatic <span class="hlt">warming</span> indicate that not all life history events are equally responsive to environmental variation. Here, we propose that our understanding of phenological response to climate change can be improved by considering entire sequences of events comprising the aggregate life histories of organisms preceding reproduction. We present results of a two-year <span class="hlt">warming</span> experiment conducted on 33 individuals of three plant species inhabiting a low-arctic site. Analysis of phenological sequences of three key events for each species revealed how the aggregate life histories preceding reproduction responded to <span class="hlt">warming</span>, and which individual events exerted the greatest influence on aggregate life history variation. For alpine chickweed (Cerastium alpinum), <span class="hlt">warming</span> elicited a shortening of the duration of the emergence stage by 2.5 days on average, but the aggregate life history did not differ between <span class="hlt">warmed</span> and ambient plots. For gray willow (Salix glauca), however, all phenological events monitored occurred earlier on <span class="hlt">warmed</span> than on ambient plots, and <span class="hlt">warming</span> reduced the aggregate life history of this species by 22 days on average. Similarly, in dwarf birch (Betula nana), <span class="hlt">warming</span> advanced flower bud set, blooming, and fruit set and reduced the aggregate life history by 27 days on average. Our approach provides important insight into life history responses of many organisms to climate change and other forms of environmental variation. Such insight may be compromised by considering changes in individual phenological events in isolation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23945416','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23945416"><span><span class="hlt">Seasonal</span> variation in the nutritional status of children aged 6 to 60 <span class="hlt">months</span> in a resettlement village in West Timor.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Miller, Jacqueline; Ritchie, Brett; Tran, Cuong; Beggs, Sean; Lada, Christina Olly; Whetter, Kathryn; Cobiac, Lynne</p> <p>2013-01-01</p> <p>Childhood malnutrition remains a public health issue in Indonesia with a national prevalence of wasting of 13% and stunting of 36%. In rural areas nutritional status depends on local agriculture and may fluctuate in relation to harvest time. The aim of this study was to characterise <span class="hlt">seasonal</span> variations in nutritional status in two resettlement villages in the Oesao district, Nusa Tenggara Timur. A cross sectional study was conducted in a convenience sample of children after the wet <span class="hlt">season</span> (March). Children aged 6 to 60 <span class="hlt">months</span> were assessed for nutritional status using anthropometric and biochemical measures. A subset of these children was re-assessed for anthropometry after the dry <span class="hlt">season</span> (November). Weight-for-height z scores improved significantly from mean±SD of -1.7± 0.9 in March to -1.3±0.9 in November (p<0.001). There was no significant change in height between <span class="hlt">seasons</span>. Prevalence of wasting, (weight-for-height z score <-2), was 42% in March and 19% in November (p<0.001). However, stunting rates increased significantly from 42% in March to 45% in November (p<0.001). Thirty six per cent of children were anaemic (Hb level <11 mg/100 mL), 68% were vitamin A deficient (plasma vitamin A level <0.8 μmol/L) and 50% were zinc deficient (plasma zinc <9.94 μmol/L). All children except one were positive for intestinal parasites. These data indicate <span class="hlt">seasonal</span> changes in anthropometry with inconsistent effects depending on the anthropometric index measured. Wasting and stunting were higher than the national average, alongside high rates of anaemia, zinc and vitamin A deficiencies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130001678','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130001678"><span>Preliminary Results of a U.S. Deep South <span class="hlt">Warm</span> <span class="hlt">Season</span> Deep Convective Initiation Modeling Experiment using NASA SPoRT Initialization Datasets for Operational National Weather Service Local Model Runs</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Medlin, Jeffrey M.; Wood, Lance; Zavodsky, Brad; Case, Jon; Molthan, Andrew</p> <p>2012-01-01</p> <p>The initiation of deep convection during the <span class="hlt">warm</span> <span class="hlt">season</span> is a forecast challenge in the relative high instability and low wind shear environment of the U.S. Deep South. Despite improved knowledge of the character of well known mesoscale features such as local sea-, bay- and land-breezes, observations show the evolution of these features fall well short in fully describing the location of first initiates. A joint collaborative modeling effort among the NWS offices in Mobile, AL, and Houston, TX, and NASA s Short-term Prediction Research and Transition (SPoRT) Center was undertaken during the 2012 <span class="hlt">warm</span> <span class="hlt">season</span> to examine the impact of certain NASA produced products on the Weather Research and Forecasting Environmental Modeling System. The NASA products were: a 4-km Land Information System data, a 1-km sea surface temperature analysis, and a 4-km greenness vegetation fraction analysis. Similar domains were established over the southeast Texas and Alabama coastlines, each with a 9 km outer grid spacing and a 3 km inner nest spacing. The model was run at each NWS office once per day out to 24 hours from 0600 UTC, using the NCEP Global Forecast System for initial and boundary conditions. Control runs without the NASA products were made at the NASA SPoRT Center. The NCAR Model Evaluation Tools verification package was used to evaluate both the forecast timing and location of the first initiates, with a focus on the impacts of the NASA products on the model forecasts. Select case studies will be presented to highlight the influence of the products.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.public.iastate.edu/~kmoloney/Instructor/Papers/2010/Yurkonis2010s.pdf','USGSPUBS'); return false;" href="http://www.public.iastate.edu/~kmoloney/Instructor/Papers/2010/Yurkonis2010s.pdf"><span>Seeding method influences <span class="hlt">warm-season</span> grass abundance and distribution but not local diversity in grassland restoration</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Yurkonis, Kathryn A.; Wilsey, Brian J.; Moloney, Kirk A.; Drobney, Pauline; Larson, Diane L.</p> <p>2010-01-01</p> <p>Ecological theory predicts that the arrangement of seedlings in newly restored communities may influence future species diversity and composition. We test the prediction that smaller distances between neighboring seeds in drill seeded grassland plantings would result in lower species diversity, greater weed abundance, and larger conspecific patch sizes than otherwise similar broadcast seeded plantings. A diverse grassland seed mix was either drill seeded, which places seeds in equally spaced rows, or broadcast seeded, which spreads seeds across the ground surface, into 24 plots in each of three sites in 2005. In summer 2007, we measured species abundance in a 1 m2 quadrat in each plot and mapped common species within the quadrat by recording the most abundant species in each of 64 cells. Quadrat-scale diversity and weed abundance were similar between drilled and broadcast plots, suggesting that processes that limited establishment and controlled invasion were not affected by such fine-scale seed distribution. However, native <span class="hlt">warm-season</span> (C4) grasses were more abundant and occurred in less compact patches in drilled plots. This difference in C4 grass abundance and distribution may result from increased germination or vegetative propagation of C4 grasses in drilled plots. Our findings suggest that local plant density may control fine-scale heterogeneity and species composition in restored grasslands, processes that need to be further investigated to determine whether seed distributions can be manipulated to increase diversity in restored grasslands.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70037688','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70037688"><span>Seeding Method Influences <span class="hlt">Warm-Season</span> Grass Abundance and Distribution but not Local Diversity in Grassland Restoration</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Yurkonis, K.A.; Wilsey, B.J.; Moloney, K.A.; Drobney, P.; Larson, D.L.</p> <p>2010-01-01</p> <p>Ecological theory predicts that the arrangement of seedlings in newly restored communities may influence future species diversity and composition. We test the prediction that smaller distances between neighboring seeds in drill seeded grassland plantings would result in lower species diversity, greater weed abundance, and larger conspecific patch sizes than otherwise similar broadcast seeded plantings. A diverse grassland seed mix was either drill seeded, which places seeds in equally spaced rows, or broadcast seeded, which spreads seeds across the ground surface, into 24 plots in each of three sites in 2005. In summer 2007, we measured species abundance in a 1 m2 quadrat in each plot and mapped common species within the quadrat by recording the most abundant species in each of 64 cells. Quadrat-scale diversity and weed abundance were similar between drilled and broadcast plots, suggesting that processes that limited establishment and controlled invasion were not affected by such fine-scale seed distribution. However, native <span class="hlt">warm-season</span> (C4) grasses were more abundant and occurred in less compact patches in drilled plots. This difference in C4 grass abundance and distribution may result from increased germination or vegetative propagation of C4 grasses in drilled plots. Our findings suggest that local plant density may control fine-scale heterogeneity and species composition in restored grasslands, processes that need to be further investigated to determine whether seed distributions can be manipulated to increase diversity in restored grasslands. ?? 2010 Society for Ecological Restoration International.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://link.springer.com/article/10.1007/s00442-015-3232-7','USGSPUBS'); return false;" href="http://link.springer.com/article/10.1007/s00442-015-3232-7"><span>Climatic controls of aboveground net primary production in semi-arid grasslands along a latitudinal gradient portend low sensitivity to <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Mowll, Whitney; Blumenthal, Dana M.; Cherwin, Karie; Smith, Anine; Symstad, Amy J.; Vermeire, Lance; Collins, Scott L.; Smith, Melinda D.; Knapp, Alan K.</p> <p>2015-01-01</p> <p>Although climate models forecast warmer temperatures with a high degree of certainty, precipitation is the primary driver of aboveground net primary production (ANPP) in most grasslands. Conversely, variations in temperature seldom are related to patterns of ANPP. Thus forecasting responses to <span class="hlt">warming</span> is a challenge, and raises the question: how sensitive will grassland ANPP be to <span class="hlt">warming</span>? We evaluated climate and multi-year ANPP data (67 years) from eight western US grasslands arrayed along mean annual temperature (MAT; ~7-14 °C) and mean annual precipitation (MAP; ~250-500 mm) gradients. Weused regression and analysis of covariance to assess relationships between ANPP and temperature, as well as precipitation (annual and growing <span class="hlt">season</span>) to evaluate temperature sensitivity of ANPP. We also related ANPP to the standardized precipitation evaporation index (SPEI), which combines precipitation and evapotranspiration to better represent moisture available for plant growth. Regression models indicated that variation in growing <span class="hlt">season</span> temperature was negatively related to total and graminoid ANPP, but precipitation was a stronger predictor than temperature. Growing <span class="hlt">season</span> temperature was also a significant parameter in more complex models, but again precipitation was consistently a stronger predictor of ANPP. Surprisingly, neither annual nor growing <span class="hlt">season</span> SPEI were as strongly related to ANPP as precipitation. We conclude that forecasted <span class="hlt">warming</span> likely will affect ANPP in these grasslands, but that predicting temperature effects from natural climatic gradients is difficult. This is because, unlike precipitation, <span class="hlt">warming</span> effects can be positive or negative and moderated by shifts in the C3/C4 ratios of plant communities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26616043','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26616043"><span><span class="hlt">Seasonality</span> of absolute humidity explains <span class="hlt">seasonality</span> of influenza-like illness in Vietnam.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Thai, Pham Quang; Choisy, Marc; Duong, Tran Nhu; Thiem, Vu Dinh; Yen, Nguyen Thu; Hien, Nguyen Tran; Weiss, Daniel J; Boni, Maciej F; Horby, Peter</p> <p>2015-12-01</p> <p>Experimental and ecological studies have shown the role of climatic factors in driving the epidemiology of influenza. In particular, low absolute humidity (AH) has been shown to increase influenza virus transmissibility and has been identified to explain the onset of epidemics in temperate regions. Here, we aim to study the potential climatic drivers of influenza-like illness (ILI) epidemiology in Vietnam, a tropical country characterized by a high diversity of climates. We specifically focus on quantifying and explaining the <span class="hlt">seasonality</span> of ILI. We used 18 years (1993-2010) of <span class="hlt">monthly</span> ILI notifications aggregated by province (52) and <span class="hlt">monthly</span> climatic variables (minimum, mean, maximum temperatures, absolute and relative humidities, rainfall and hours of sunshine) from 67 weather stations across Vietnam. <span class="hlt">Seasonalities</span> were quantified from global wavelet spectra, using the value of the power at the period of 1 year as a measure of the intensity of <span class="hlt">seasonality</span>. The 7 climatic time series were characterized by 534 summary statistics which were entered into a regression tree to identify factors associated with the <span class="hlt">seasonality</span> of AH. Results were extrapolated to the global scale using simulated climatic times series from the NCEP/NCAR project. The intensity of ILI <span class="hlt">seasonality</span> in Vietnam is best explained by the intensity of AH <span class="hlt">seasonality</span>. We find that ILI <span class="hlt">seasonality</span> is weak in provinces experiencing weak <span class="hlt">seasonal</span> fluctuations in AH (annual power <17.6), whereas ILI <span class="hlt">seasonality</span> is strongest in provinces with pronounced AH <span class="hlt">seasonality</span> (power >17.6). In Vietnam, AH and ILI are positively correlated. Our results identify a role for AH in driving the epidemiology of ILI in a tropical setting. However, in contrast to temperate regions, high rather than low AH is associated with increased ILI activity. Fluctuation in AH may be the climate factor that underlies and unifies the <span class="hlt">seasonality</span> of ILI in both temperate and tropical regions. Alternatively, the mechanism of action of</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" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29801654','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29801654"><span><span class="hlt">Seasonal</span> variation in the thermal biology of a terrestrial toad, Rhinella icterica (Bufonidae), from the Brazilian Atlantic Forest.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Anderson, Rodolfo César de Oliveira; Bovo, Rafael Parelli; Andrade, Denis Vieira</p> <p>2018-05-01</p> <p>As ectotherms, amphibians may exhibit changes in their thermal biology associated with spatial and temporal environmental contingencies. However, our knowledge on how amphibian´s thermal biology responds to <span class="hlt">seasonal</span> changes in the environment is restricted to a few species, mostly from temperate regions, in a marked contrast with the high species diversity found in the Neotropics. We investigated whether or not the <span class="hlt">seasonal</span> variation in climatic parameters from a high-montane ombrophilous forest in the Brazilian Atlantic Forest could lead to concurrent adjustments in the thermal biology of the terrestrial toad Rhinella icterica. We measured active body temperature (T b ) in the field, and preferred body temperature (T pref ) and thermal tolerance (critical thermal minimum, CT min , and maximum, CT max ) in the laboratory, for toads collected at two distinct <span class="hlt">seasons</span>: <span class="hlt">warm</span>/wet and cold/dry. We also measured operative environmental temperatures (T e ) using agar toad models coupled with dataloggers distributed in different microhabitats in the field to estimate accuracy (d b ) and effectiveness (E) of thermoregulation of the toads for both <span class="hlt">seasons</span>. Toads had higher T pref in the <span class="hlt">warm</span>/wet <span class="hlt">season</span> compared to the cold/dry <span class="hlt">season</span>, even though no <span class="hlt">seasonal</span> change occurred in field T b 's. In the <span class="hlt">warm</span>/wet <span class="hlt">season</span>, toads decreased the accuracy of thermoregulation and avoided thermally favorable microhabitats, while in the cold/dry <span class="hlt">season</span> they increased the accuracy of thermoregulation and exhibited high degree of thermoconformity. This result may encompass thermoregulatory adjustments to <span class="hlt">seasonal</span> changes in T e 's, but may also reflect <span class="hlt">seasonal</span> differences in compromises between T b regulation and other ecologically relevant activities (reproduction, foraging). Toads did not exhibit changes in CT min or CT max , which indicates a low risk of exposure to extreme temperatures in this particular habitat, at both <span class="hlt">seasons</span>, possibly combined with a low flexibility of this trait</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018GeoRL..45.3285N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018GeoRL..45.3285N"><span>Global Changes in Drought Conditions Under Different Levels of <span class="hlt">Warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Naumann, G.; Alfieri, L.; Wyser, K.; Mentaschi, L.; Betts, R. A.; Carrao, H.; Spinoni, J.; Vogt, J.; Feyen, L.</p> <p>2018-04-01</p> <p>Higher evaporative demands and more frequent and persistent dry spells associated with rising temperatures suggest that drought conditions could worsen in many regions of the world. In this study, we assess how drought conditions may develop across the globe for 1.5, 2, and 3°C <span class="hlt">warming</span> compared to preindustrial temperatures. Results show that two thirds of global population will experience a progressive increase in drought conditions with <span class="hlt">warming</span>. For drying areas, drought durations are projected to rise at rapidly increasing rates with <span class="hlt">warming</span>, averaged globally from 2.0 <span class="hlt">month</span>/°C below 1.5°C to 4.2 <span class="hlt">month</span>/°C when approaching 3°C. Drought magnitudes could double for 30% of global landmass under stringent mitigation. If contemporary <span class="hlt">warming</span> rates continue, water supply-demand deficits could become fivefold in size for most of Africa, Australia, southern Europe, southern and central states of the United States, Central America, the Caribbean, north-west China, and parts of Southern America. In approximately 20% of the global land surface, drought magnitude will halve with <span class="hlt">warming</span> of 1.5°C and higher levels, mainly most land areas north of latitude 55°N, but also parts of South America and Eastern and South-eastern Asia. A progressive and significant increase in frequency of droughts is projected with <span class="hlt">warming</span> in the Mediterranean basin, most of Africa, West and Southern Asia, Central America, and Oceania, where droughts are projected to happen 5 to 10 times more frequent even under ambitious mitigation targets and current 100-year events could occur every two to five years under 3°C of <span class="hlt">warming</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21295829','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21295829"><span>Effect of <span class="hlt">season</span>, <span class="hlt">month</span> of parturition and lactation on estrus behavior and ovarian activity in Barki x Rahmani crossbred ewes under subtropical conditions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hashem, N M; El-Zarkouny, S Z; Taha, T A; Abo-Elezz, Z R</p> <p>2011-04-15</p> <p>The correlations between some meteorological parameters and fertility data were evaluated in Barki x Rahmani crossbred ewes using the records of five consecutive years (2003-2007). Additionally, estrus detection and ultrasonic evaluation were applied on eighteen mature dry ewes during breeding and non-breeding <span class="hlt">seasons</span>. The effect of lactation was evaluated by monitoring estrus behavior in ninety four lactating ewes from 40 to 120 d after parturition. Moreover, ultrasonography was used to identify ovarian activity in six cyclic and six acyclic non-lactating ewes. Results revealed that relative estrus occurrence and fertile mating were positively correlated (P <0.05) with high temperature and long photoperiod (conditions of summer <span class="hlt">season</span>), and were negatively correlated (P < 0.01) with rainfall (condition of winter <span class="hlt">season</span>). During breeding <span class="hlt">season</span>, estrus rate, serum progesterone concentration, and diameter of largest follicle were significantly (P < 0.05) higher than those observed during the non-breeding <span class="hlt">season</span>. Furthermore, <span class="hlt">month</span> of parturition had a significant effect (P < 0.05) on estrus rate of lactating ewes where ewes that lambed in August, September, and October recorded higher estrus rate than those lambed in November and December. However, the lactational strength did not exert any deleterious effect on the reproductive performance of lactating ewes. In conclusion, in Egypt under subtropical conditions, Barki x Rahmani crossbred ewes exerted optimum estrus behavior and fertile mating during summer <span class="hlt">season</span>. The reduction in estrus activity during lactation was due to the <span class="hlt">seasonal</span> effect rather than lactational stress. Copyright © 2011 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29410739','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29410739"><span>Retrospectively reported <span class="hlt">month-to-month</span> variation in sleeping problems of people naturally exposed to high-amplitude annual variation in daylength and/or temperature.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Putilov, Arcady A</p> <p>2017-01-01</p> <p>Compared to literature on <span class="hlt">seasonal</span> variation in mood and well-being, reports on <span class="hlt">seasonality</span> of trouble sleeping are scarce and contradictive. To extend geography of such reports on example of people naturally exposed to high-amplitude annual variation in daylength and/or temperature. Participants were the residents of Turkmenia, West Siberia, South and North Yakutia, Chukotka, and Alaska. Health and sleep-wake adaptabilities, <span class="hlt">month-to-month</span> variation in sleeping problems, well-being and behaviors were self-assessed. More than a half of 2398 respondents acknowledged <span class="hlt">seasonality</span> of sleeping problems. Four of the assessed sleeping problems demonstrated three different patterns of <span class="hlt">seasonal</span> variation. Rate of the problems significantly increased in winter <span class="hlt">months</span> with long nights and cold days (daytime sleepiness and difficulties falling and staying asleep) as well as in summer <span class="hlt">months</span> with either long days (premature awakening and difficulties falling and staying asleep) or hot nights and days (all 4 sleeping problems). Individual differences between respondents in pattern and level of <span class="hlt">seasonality</span> of sleeping problems were significantly associated with differences in several other domains of individual variation, such as gender, age, ethnicity, physical health, morning-evening preference, sleep quality, and adaptability of the sleep-wake cycle. These results have practical relevance to understanding of the roles playing by natural environmental factors in <span class="hlt">seasonality</span> of sleeping problems as well as to research on prevalence of sleep disorders and methods of their prevention and treatment in regions with large <span class="hlt">seasonal</span> differences in temperature and daylength.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.H43E0547L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.H43E0547L"><span>Processes Controlling Baseflow and Climatic <span class="hlt">Warming</span> Effects in Merced River, Sierra Nevada, California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, F.; Conklin, M. H.; Shaw, G.; Bales, R. C.; Conrad, M. E.; Rice, R.</p> <p>2006-12-01</p> <p>Sources of streamflow in Merced River were determined using stable isotopes and chemical tracers in order to improve our understanding of hydrologic controls on streamflow and their relationship with climatic <span class="hlt">warming</span> in the region. Samples were collected from streamflow, groundwater, and natural springs from 2003 to 2006. Both stable isotopes and specific conductivity in streamflow showed a strong <span class="hlt">seasonality</span>, with lower values from April to July during the snowmelt <span class="hlt">season</span>, higher values from August to October during dry <span class="hlt">season</span>, and intermediate values from November to March during winter rainfall and snowfall. Two components controlling baseflow (streamflow from August to October) in the Upper Merced River were identified: shallow subsurface runoff from snowmelt infiltration and groundwater from fractured bedrock. Conductivity in baseflow increased rapidly with discharge, following a power law (R2 > 0.96, p < 0.05), and peaked in October, indicating that the contribution of shallow subsurface runoff to baseflow was significant but decreased rapidly from August to October. Baseflow appears to be very sensitive to the snowmelt timing and regime. From 1976 to 2005, during a period of increasing temperature in the region, streamflow tended to decrease significantly during October (p < 0.05) and increase during March (p < 0.05). However, total annual precipitation did not change significantly, indicating that the shift in baseflow discharge is a result of the early onset of snowmelt due to climatic <span class="hlt">warming</span>. If climatic <span class="hlt">warming</span> continues in the region, baseflow in the Sierra Nevada may continue decreasing and water supply may suffer increased stress during the late summer, high water-demand period.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4807827','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4807827"><span>Opposing Patterns of <span class="hlt">Seasonal</span> Change in Functional and Phylogenetic Diversity of Tadpole Assemblages</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Strauß, Axel; Guilhaumon, François; Randrianiaina, Roger Daniel; Wollenberg Valero, Katharina C.; Vences, Miguel; Glos, Julian</p> <p>2016-01-01</p> <p>Assemblages that are exposed to recurring temporal environmental changes can show changes in their ecological properties. These can be expressed by differences in diversity and assembly rules. Both can be identified using two measures of diversity: functional (FD) and phylogenetic diversity (PD). Frog communities are understudied in this regard, especially during the tadpole life stage. We utilised tadpole assemblages from Madagascan rainforest streams to test predictions of <span class="hlt">seasonal</span> changes on diversity and assemblage composition and on diversity measures. From the <span class="hlt">warm</span>-wet to the cool-dry <span class="hlt">season</span>, species richness (SR) of tadpole assemblages decreased. Also FD and PD decreased, but FD less and PD more than expected by chance. During the dry <span class="hlt">season</span>, tadpole assemblages were characterised by functional redundancy (among assemblages—with increasing SR), high FD (compared to a null model), and low PD (phylogenetic clustering; compared to a null model). Although mutually contradictory at first glance, these results indicate competition as tadpole community assembly driving force. This is true during the limiting cool-dry <span class="hlt">season</span> but not during the more suitable <span class="hlt">warm</span>-wet <span class="hlt">season</span>. We thereby show that assembly rules can strongly depend on <span class="hlt">season</span>, that comparing FD and PD can reveal such forces, that FD and PD are not interchangeable, and that conclusions on assembly rules based on FD alone are critical. PMID:27014867</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ghr.nlm.nih.gov/condition/seasonal-affective-disorder','NIH-MEDLINEPLUS'); return false;" href="https://ghr.nlm.nih.gov/condition/seasonal-affective-disorder"><span>Genetics Home Reference: <span class="hlt">seasonal</span> affective disorder</span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... <span class="hlt">seasonal</span> affective disorder are complex. A shortage of sunlight contributes to the development of the disorder in the fall and winter <span class="hlt">months</span>, and too much sunlight is associated with <span class="hlt">seasonal</span> affective disorder in the ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26236957','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26236957"><span>Maternal history of parentification and <span class="hlt">warm</span> responsiveness: The mediating role of knowledge of infant development.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nuttall, Amy K; Valentino, Kristin; Wang, Lijuan; Lefever, Jennifer Burke; Borkowski, John G</p> <p>2015-12-01</p> <p>Maternal history of parentification in the family of origin poses subsequent risk to parenting quality during the transition to parenthood. The present study builds on prior work by evaluating whether the association between maternal parentification history and <span class="hlt">warm</span> responsiveness is mediated by maternal knowledge of infant development in first time mothers. Using data from a prospective longitudinal study on the transition to motherhood, maternal knowledge of infant development and observational codings of <span class="hlt">warm</span> responsiveness were examined across the first 18 <span class="hlt">months</span> of parenthood for 374 mothers who also provided retrospective reports of their childhood parentification experiences. Results indicated that maternal retrospective reports of higher engagement in parentified roles in family of origin were associated with poorer knowledge of infant development across the first 18 <span class="hlt">months</span> of parenthood and, in turn, less <span class="hlt">warm</span> responsiveness with 18-<span class="hlt">month</span>-old children. However, maternal parentification history did not significantly influence changes in maternal <span class="hlt">warm</span> responsiveness across the transition to parenthood. These findings suggest that preventive interventions targeting maternal knowledge of infant development as early as the prenatal period may be useful for preventing poor <span class="hlt">warm</span> responsiveness. (c) 2015 APA, all rights reserved).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018IJBm...62..387J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018IJBm...62..387J"><span>Outdoor thermal comfort in public space in <span class="hlt">warm</span>-humid Guayaquil, Ecuador</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Johansson, Erik; Yahia, Moohammed Wasim; Arroyo, Ivette; Bengs, Christer</p> <p>2018-03-01</p> <p>The thermal environment outdoors affects human comfort and health. Mental and physical performance is reduced at high levels of air temperature being a problem especially in tropical climates. This paper deals with human comfort in the <span class="hlt">warm</span>-humid city of Guayaquil, Ecuador. The main aim was to examine the influence of urban micrometeorological conditions on people's subjective thermal perception and to compare it with two thermal comfort indices: the physiologically equivalent temperature (PET) and the standard effective temperature (SET*). The outdoor thermal comfort was assessed through micrometeorological measurements of air temperature, humidity, mean radiant temperature and wind speed together with a questionnaire survey consisting of 544 interviews conducted in five public places of the city during both the dry and rainy <span class="hlt">seasons</span>. The neutral and preferred values as well as the upper comfort limits of PET and SET* were determined. For both indices, the neutral values and upper thermal comfort limits were lower during the rainy <span class="hlt">season</span>, whereas the preferred values were higher during the rainy <span class="hlt">season</span>. Regardless of <span class="hlt">season</span>, the neutral values of PET and SET* are above the theoretical neutral value of each index. The results show that local people accept thermal conditions which are above acceptable comfort limits in temperate climates and that the subjective thermal perception varies within a wide range. It is clear, however, that the majority of the people in Guayaquil experience the outdoor thermal environment during daytime as too <span class="hlt">warm</span>, and therefore, it is important to promote an urban design which creates shade and ventilation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28283758','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28283758"><span>Outdoor thermal comfort in public space in <span class="hlt">warm</span>-humid Guayaquil, Ecuador.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Johansson, Erik; Yahia, Moohammed Wasim; Arroyo, Ivette; Bengs, Christer</p> <p>2018-03-01</p> <p>The thermal environment outdoors affects human comfort and health. Mental and physical performance is reduced at high levels of air temperature being a problem especially in tropical climates. This paper deals with human comfort in the <span class="hlt">warm</span>-humid city of Guayaquil, Ecuador. The main aim was to examine the influence of urban micrometeorological conditions on people's subjective thermal perception and to compare it with two thermal comfort indices: the physiologically equivalent temperature (PET) and the standard effective temperature (SET*). The outdoor thermal comfort was assessed through micrometeorological measurements of air temperature, humidity, mean radiant temperature and wind speed together with a questionnaire survey consisting of 544 interviews conducted in five public places of the city during both the dry and rainy <span class="hlt">seasons</span>. The neutral and preferred values as well as the upper comfort limits of PET and SET* were determined. For both indices, the neutral values and upper thermal comfort limits were lower during the rainy <span class="hlt">season</span>, whereas the preferred values were higher during the rainy <span class="hlt">season</span>. Regardless of <span class="hlt">season</span>, the neutral values of PET and SET* are above the theoretical neutral value of each index. The results show that local people accept thermal conditions which are above acceptable comfort limits in temperate climates and that the subjective thermal perception varies within a wide range. It is clear, however, that the majority of the people in Guayaquil experience the outdoor thermal environment during daytime as too <span class="hlt">warm</span>, and therefore, it is important to promote an urban design which creates shade and ventilation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016HESS...20.4359S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016HESS...20.4359S"><span>Regionalization of <span class="hlt">monthly</span> rainfall erosivity patternsin Switzerland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schmidt, Simon; Alewell, Christine; Panagos, Panos; Meusburger, Katrin</p> <p>2016-10-01</p> <p><p class="p">One major controlling factor of water erosion is rainfall erosivity, which is quantified as the product of total storm energy and a maximum 30 min intensity (I30). Rainfall erosivity is often expressed as R-factor in soil erosion risk models like the Universal Soil Loss Equation (USLE) and its revised version (RUSLE). As rainfall erosivity is closely correlated with rainfall amount and intensity, the rainfall erosivity of Switzerland can be expected to have a regional characteristic and <span class="hlt">seasonal</span> dynamic throughout the year. This intra-annual variability was mapped by a <span class="hlt">monthly</span> modeling approach to assess simultaneously spatial and <span class="hlt">monthly</span> patterns of rainfall erosivity. So far only national <span class="hlt">seasonal</span> means and regional annual means exist for Switzerland. We used a network of 87 precipitation gauging stations with a 10 min temporal resolution to calculate long-term <span class="hlt">monthly</span> mean R-factors. Stepwise generalized linear regression (GLM) and leave-one-out cross-validation (LOOCV) were used to select spatial covariates which explain the spatial and temporal patterns of the R-factor for each <span class="hlt">month</span> across Switzerland. The <span class="hlt">monthly</span> R-factor is mapped by summarizing the predicted R-factor of the regression equation and the corresponding residues of the regression, which are interpolated by ordinary kriging (regression-kriging). As spatial covariates, a variety of precipitation indicator data has been included such as snow depths, a combination product of hourly precipitation measurements and radar observations (CombiPrecip), daily Alpine precipitation (EURO4M-APGD), and <span class="hlt">monthly</span> precipitation sums (RhiresM). Topographic parameters (elevation, slope) were also significant explanatory variables for single <span class="hlt">months</span>. The comparison of the 12 <span class="hlt">monthly</span> rainfall erosivity maps showed a distinct <span class="hlt">seasonality</span> with the highest rainfall erosivity in summer (June, July, and August) influenced by intense rainfall events. Winter <span class="hlt">months</span> have the lowest rainfall erosivity. A proportion</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.B33H..07X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.B33H..07X"><span>Effects of <span class="hlt">seasonal</span> snow and climatic controls on spring and autumn phenology in Alpine forest regions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xie, J.; Kneubühler, M.; Garonna, I.; Jong, R. D.; Schaepman, M. E.</p> <p>2017-12-01</p> <p><span class="hlt">Seasonal</span> accumulation and melt of snow in mountainous regions varies with meteorological factors and affects forest phenology in various ways. However, our knowledge about the relationship between <span class="hlt">seasonal</span> snow and forest phenology - and particularly its topographical variation - is still limited and needs further investigation. We tested the relationship between a number of snow, meteorological and land surface phenology metrics (satellite-derived and gridded) in the forested regions of the Swiss Alps for the period of 2003-2014. Satellite-derived start of <span class="hlt">season</span> and end of <span class="hlt">season</span> metrics (SOS and EOS, respectively), in combination with snow accumulation (SA), snow cover melt date (SCMD), <span class="hlt">monthly</span> maximum, mean and minimum temperature, <span class="hlt">monthly</span> mean relative sunshine duration and precipitation were considered in our analysis. We calculated Spearman's rank correlation of interannual differences (Δ) of SOS and EOS with snow and meteorological metrics and examined the variation of these correlations with elevation (from 200 up to 2400 meter above sea level (m a.s.l.)). We found SOS to have a significant (p < 0.05) positive correlation with both SCMD (mean R=0.71, over 34.2% of all pixels) and SA (mean R=0.62, over 19.0% of all pixels). On the other hand, SOS showed a significant negative correlation with spring temperature and relative sunshine duration. EOS showed significant positive correlation with autumn temperature (mean R=0.70, over 30.4% of all pixels). Moreover, we found the forest phenology of the northern and eastern Swiss Alps to be more sensitive to <span class="hlt">seasonal</span> snow but less sensitive to meteorological factors than in the southern and western Swiss Alps. The areas which are sensitive to <span class="hlt">seasonal</span> snow and meteorological factors are more pronounced at higher elevations. We conclude that the effect of snow melt on spring phenology is of equal magnitude as spring temperature and relative sunshine duration. Autumn forest phenology is mainly influenced by autumn</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28662123','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28662123"><span>Effects of different re-<span class="hlt">warm</span> up activities in football players' performance.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Abade, Eduardo; Sampaio, Jaime; Gonçalves, Bruno; Baptista, Jorge; Alves, Alberto; Viana, João</p> <p>2017-01-01</p> <p><span class="hlt">Warm</span> up routines are commonly used to optimize football performance and prevent injuries. Yet, official pre-match protocols may require players to passively rest for approximately 10 to 15 minutes between the <span class="hlt">warm</span> up and the beginning of the match. Therefore, the aim of this study was to explore the effect of different re-<span class="hlt">warm</span> up activities on the physical performance of football players. Twenty-Two Portuguese elite under-19 football players participated in the study conducted during the competitive <span class="hlt">season</span>. Different re-<span class="hlt">warm</span> up protocols were performed 6 minutes after the same standardized <span class="hlt">warm</span> up in 4 consecutive days in a crossover controlled approach: without, eccentric, plyometric and repeated changes of direction. Vertical jump and Sprint performances were tested immediately after <span class="hlt">warm</span> up and 12 minutes after <span class="hlt">warm</span> up. Results showed that repeated changes of direction and plyometrics presented beneficial effects to jump and sprint. Different practical implications may be taken from the eccentric protocol since a vertical jump impairment was observed, suggesting a possibly harmful effect. The absence of re-<span class="hlt">warm</span> up activities may be detrimental to players' physical performance. However, the inclusion of re-<span class="hlt">warm</span> up prior to match is a complex issue, since the manipulation of volume, intensity and recovery may positively or negatively affect the subsequent performance. In fact, this exploratory study shows that eccentric exercise may be harmful for physical performance when performed prior a football match. However, plyometric and repeated changes of direction exercises seem to be simple, quick and efficient activities to attenuate losses in vertical jump and sprint capacity after <span class="hlt">warm</span> up. Coaches should aim to develop individual optimal exercise modes in order to optimize physical performance after re <span class="hlt">warm</span> activities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25736981','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25736981"><span>Temperature alone does not explain phenological variation of diverse temperate plants under experimental <span class="hlt">warming</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Marchin, Renée M; Salk, Carl F; Hoffmann, William A; Dunn, Robert R</p> <p>2015-08-01</p> <p>Anthropogenic climate change has altered temperate forest phenology, but how these trends will play out in the future is controversial. We measured the effect of experimental <span class="hlt">warming</span> of 0.6-5.0 °C on the phenology of a diverse suite of 11 plant species in the deciduous forest understory (Duke Forest, North Carolina, USA) in a relatively <span class="hlt">warm</span> year (2011) and a colder year (2013). Our primary goal was to dissect how temperature affects timing of spring budburst, flowering, and autumn leaf coloring for functional groups with different growth habits, phenological niches, and xylem anatomy. <span class="hlt">Warming</span> advanced budburst of six deciduous woody species by 5-15 days and delayed leaf coloring by 18-21 days, resulting in an extension of the growing <span class="hlt">season</span> by as much as 20-29 days. Spring temperature accumulation was strongly correlated with budburst date, but temperature alone cannot explain the diverse budburst responses observed among plant functional types. Ring-porous trees showed a consistent temperature response pattern across years, suggesting these species are sensitive to photoperiod. Conversely, diffuse-porous species responded differently between years, suggesting winter chilling may be more important in regulating budburst. Budburst of the ring-porous Quercus alba responded nonlinearly to <span class="hlt">warming</span>, suggesting evolutionary constraints may limit changes in phenology, and therefore productivity, in the future. <span class="hlt">Warming</span> caused a divergence in flowering times among species in the forest community, resulting in a longer flowering <span class="hlt">season</span> by 10-16 days. Temperature was a good predictor of flowering for only four of the seven species studied here. Observations of interannual temperature variability overpredicted flowering responses in spring-blooming species, relative to our <span class="hlt">warming</span> experiment, and did not consistently predict even the direction of flowering shifts. Experiments that push temperatures beyond historic variation are indispensable for improving predictions of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...48.3247F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...48.3247F"><span>Evaluating Arctic <span class="hlt">warming</span> mechanisms in CMIP5 models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Franzke, Christian L. E.; Lee, Sukyoung; Feldstein, Steven B.</p> <p>2017-05-01</p> <p>Arctic <span class="hlt">warming</span> is one of the most striking signals of global <span class="hlt">warming</span>. The Arctic is one of the fastest <span class="hlt">warming</span> regions on Earth and constitutes, thus, a good test bed to evaluate the ability of climate models to reproduce the physics and dynamics involved in Arctic <span class="hlt">warming</span>. Different physical and dynamical mechanisms have been proposed to explain Arctic amplification. These mechanisms include the surface albedo feedback and poleward sensible and latent heat transport processes. During the winter <span class="hlt">season</span> when Arctic amplification is most pronounced, the first mechanism relies on an enhancement in upward surface heat flux, while the second mechanism does not. In these mechanisms, it has been proposed that downward infrared radiation (IR) plays a role to a varying degree. Here, we show that the current generation of CMIP5 climate models all reproduce Arctic <span class="hlt">warming</span> and there are high pattern correlations—typically greater than 0.9—between the surface air temperature (SAT) trend and the downward IR trend. However, we find that there are two groups of CMIP5 models: one with small pattern correlations between the Arctic SAT trend and the surface vertical heat flux trend (Group 1), and the other with large correlations (Group 2) between the same two variables. The Group 1 models exhibit higher pattern correlations between Arctic SAT and 500 hPa geopotential height trends, than do the Group 2 models. These findings suggest that Arctic <span class="hlt">warming</span> in Group 1 models is more closely related to changes in the large-scale atmospheric circulation, whereas in Group 2, the albedo feedback effect plays a more important role. Interestingly, while Group 1 models have a <span class="hlt">warm</span> or weak bias in their Arctic SAT, Group 2 models show large cold biases. This stark difference in model bias leads us to hypothesize that for a given model, the dominant Arctic <span class="hlt">warming</span> mechanism and trend may be dependent on the bias of the model mean state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1248412-ecosystem-warming-increases-sap-flow-rates-northern-red-oak-trees','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1248412-ecosystem-warming-increases-sap-flow-rates-northern-red-oak-trees"><span>Ecosystem <span class="hlt">warming</span> increases sap flow rates of northern red oak trees</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Juice, Stephanie M.; Templer, Pamela H.; Phillips, Nathan G.; ...</p> <p>2016-03-17</p> <p>Over the next century, air temperature increases up to 5°C are projected for the northeastern United States. As evapotranspiration strongly influences water loss from terrestrial ecosystems, the ecophysiological response of trees to <span class="hlt">warming</span> will have important consequences for forest water budgets. We measured growing <span class="hlt">season</span> sap flow rates in mature northern red oak ( Quercus rubra L.) trees in a combined air (up to 5.5°C above ambient) and soil (up to 1.85°C above ambient at 6-cm depth) <span class="hlt">warming</span> experiment at Harvard Forest, Massachusetts, United States. Through principal components analysis, we found air and soil temperatures explained the largest amount ofmore » variance in environmental variables associated with rates of sap flow, with relative humidity, photosynthetically active radiation and vapor pressure deficit having significant, but smaller, effects. On average, each 1°C increase in temperature increased sap flow rates by approximately 1100 kg H 2O m -2 sapwood area day-1 throughout the growing <span class="hlt">season</span> and by 1200 kg H 2O m -2 sapwood area day -1 during the early growing <span class="hlt">season</span>. Reductions in the number of cold winter days correlated positively with increased sap flow during the early growing <span class="hlt">season</span> (a decrease in 100 heating-degree days was associated with a sapflow increase in approximately 5 kg H 2O m -2 sapwood area day -1). Soil moisture declined with increased treatment temperatures, and each soil moisture percentage decrease resulted in a decrease in sap flow of approximately 360 kg H2O m -22 sapwood area day -1. At night, soil moisture correlated positively with sap flow. Finally, these results demonstrate that warmer air and soil temperatures in winter and throughout the growing <span class="hlt">season</span> lead to increased sap flow rates, which could affect forest water budgets throughout the year.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1248412-ecosystem-warming-increases-sap-flow-rates-northern-red-oak-trees','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1248412-ecosystem-warming-increases-sap-flow-rates-northern-red-oak-trees"><span>Ecosystem <span class="hlt">warming</span> increases sap flow rates of northern red oak trees</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Juice, Stephanie M.; Templer, Pamela H.; Phillips, Nathan G.</p> <p></p> <p>Over the next century, air temperature increases up to 5°C are projected for the northeastern United States. As evapotranspiration strongly influences water loss from terrestrial ecosystems, the ecophysiological response of trees to <span class="hlt">warming</span> will have important consequences for forest water budgets. We measured growing <span class="hlt">season</span> sap flow rates in mature northern red oak ( Quercus rubra L.) trees in a combined air (up to 5.5°C above ambient) and soil (up to 1.85°C above ambient at 6-cm depth) <span class="hlt">warming</span> experiment at Harvard Forest, Massachusetts, United States. Through principal components analysis, we found air and soil temperatures explained the largest amount ofmore » variance in environmental variables associated with rates of sap flow, with relative humidity, photosynthetically active radiation and vapor pressure deficit having significant, but smaller, effects. On average, each 1°C increase in temperature increased sap flow rates by approximately 1100 kg H 2O m -2 sapwood area day-1 throughout the growing <span class="hlt">season</span> and by 1200 kg H 2O m -2 sapwood area day -1 during the early growing <span class="hlt">season</span>. Reductions in the number of cold winter days correlated positively with increased sap flow during the early growing <span class="hlt">season</span> (a decrease in 100 heating-degree days was associated with a sapflow increase in approximately 5 kg H 2O m -2 sapwood area day -1). Soil moisture declined with increased treatment temperatures, and each soil moisture percentage decrease resulted in a decrease in sap flow of approximately 360 kg H2O m -22 sapwood area day -1. At night, soil moisture correlated positively with sap flow. Finally, these results demonstrate that warmer air and soil temperatures in winter and throughout the growing <span class="hlt">season</span> lead to increased sap flow rates, which could affect forest water budgets throughout the year.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRG..123..509J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRG..123..509J"><span><span class="hlt">Seasonal</span> and Spatial Changes in Trichodesmium Associated With Physicochemical Properties in East China Sea and Southern Yellow Sea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jiang, Zhibing; Li, Hongliang; Zhai, Hongchang; Zhou, Feng; Chen, Quanzhen; Chen, Jianfang; Zhang, Dongsheng; Yan, Xiaojun</p> <p>2018-02-01</p> <p>Trichodesmium is broadly distributed and occasionally blooms in the East China Sea (ECS) and southern Yellow Sea, where it contributes to local N and C budgets. However, its population structure, spatiotemporal distribution, controlling factors, and N2 fixation remain poorly documented. Here we provide high spatial resolution data sets of Trichodesmium during the four <span class="hlt">seasons</span> of 2011-2012 using water- and net-collected methods. The net-collected method captures colonial trichomes of Trichodesmium effectively but results in an underestimation of free trichomes. Colonies are rarely observed and occur only on the ECS shelf, which are easily missed in water-collected samples. Depth-integrated densities of Trichodesmium were found to be significantly higher in <span class="hlt">warm</span> <span class="hlt">seasons</span> than in cold <span class="hlt">seasons</span>. Maximum densities in the water column were generally found at depths of 10-50 m. Trichodesmium thrives on the oligotrophic, <span class="hlt">warm</span>, offshore ECS shelf (controlled by the Kuroshio and Taiwan <span class="hlt">Warm</span> Current), but restrains in the cold southern Yellow Sea and the eutrophic, inshore ECS. <span class="hlt">Seasonal</span> and spatial variations in Trichodesmium are closely correlated with physicochemical properties (mainly temperature and P), which are primarily controlled by circulation alteration and water mass movement. The N2 fixation rates of Trichodesmium in the ECS in summer and autumn (>20°C) are roughly estimated at 17.1 and 41.7 μmol N m-2 d-1 under nonbloom conditions, which potentially contribute to 81% and 57% of biological N2 fixation, respectively. Compared with historical data since the 1970s, Trichodesmium densities have increased considerably in all <span class="hlt">seasons</span>, and the distribution boundary has shifted northward under regional <span class="hlt">warming</span> and hydrological changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B31K..01Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B31K..01Z"><span>Metagenomics-Enabled Understanding of Soil Microbial Feedbacks to Climate <span class="hlt">Warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, J.; Wu, L.; Zhili, H.; Kostas, K.; Luo, Y.; Schuur, E. A. G.; Cole, J. R.; Tiedje, J. M.</p> <p>2014-12-01</p> <p>Understanding the response of biological communities to climate <span class="hlt">warming</span> is a central issue in ecology and global change biology, but it is poorly understood microbial communities. To advance system-level predictive understanding of the feedbacks of belowground microbial communities to multiple climate change factors and their impacts on soil carbon (C) and nitrogen (N) cycling processes, we have used integrated metagenomic technologies (e.g., target gene and shotgun metagenome sequencing, GeoChip, and isotope) to analyze soil microbial communities from experimental <span class="hlt">warming</span> sites in Alaska (AK) and Oklahoma (OK), and long-term laboratory incubation. Rapid feedbacks of microbial communities to <span class="hlt">warming</span> were observed in the AK site. Consistent with the changes in soil temperature, moisture and ecosystem respiration, microbial functional community structure was shifted after only 1.5-year <span class="hlt">warming</span>, indicating rapid responses and high sensitivity of this permafrost ecosystem to climate <span class="hlt">warming</span>. Also, <span class="hlt">warming</span> stimulated not only functional genes involved in aerobic respiration of both labile and recalcitrant C, contributing to an observed 24% increase in 2010 growing <span class="hlt">season</span> and 56% increase of decomposition of a standard substrate, but also functional genes for anaerobic processes (e.g., denitrification, sulfate reduction, methanogenesis). Further comparisons by shotgun sequencing showed significant differences of microbial community structure between AK and OK sites. The OK site was enriched in genes annotated for cellulose degradation, CO2 production, denitrification, sporulation, heat shock response, and cellular surface structures (e.g., trans-membrane transporters for glucosides), while the AK <span class="hlt">warmed</span> plots were enriched in metabolic pathways related to labile C decomposition. Together, our results demonstrate the vulnerability of permafrost ecosystem C to climate <span class="hlt">warming</span> and the importance of microbial feedbacks in mediating such vulnerability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AcGeo..58.1115K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AcGeo..58.1115K"><span><span class="hlt">Seasonal</span> temperature extremes in Potsdam</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kundzewicz, Zbigniew; Huang, Shaochun</p> <p>2010-12-01</p> <p>The awareness of global <span class="hlt">warming</span> is well established and results from the observations made on thousands of stations. This paper complements the large-scale results by examining a long time-series of high-quality temperature data from the Secular Meteorological Station in Potsdam, where observation records over the last 117 years, i.e., from January 1893 are available. Tendencies of change in <span class="hlt">seasonal</span> temperature-related climate extremes are demonstrated. "Cold" extremes have become less frequent and less severe than in the past, while "<span class="hlt">warm</span>" extremes have become more frequent and more severe. Moreover, the interval of the occurrence of frost has been decreasing, while the interval of the occurrence of hot days has been increasing. However, many changes are not statistically significant, since the variability of temperature indices at the Potsdam station has been very strong.</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" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMPP33B1661W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMPP33B1661W"><span>Paleoclimate of the Neoglacial and Roman <span class="hlt">Warm</span> Period Reconstructed from Oxygen Isotope Ratios of Limpet Shells (Patella vulgata), Northwest Scotland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, T.; Surge, D. M.; Mithen, S.</p> <p>2010-12-01</p> <p> study area, which averages 7.40±0.35°C for coldest <span class="hlt">month</span> and 14.12±0.54°C for warmest <span class="hlt">month</span>. Our reconstructed temperatures from the Neoglacial limpets showed slightly (0-1°C) colder winters, similar or warmer (1-1.8°C) summers compared to present SST record. One shell captured a year without a summer likely resulting from an eruption of the Katla volcanic system in Iceland. The reconstructed temperatures from the Roman <span class="hlt">Warm</span> Period limpets showed colder winters (up to 2°C) and similar summers compared with present SST record. Our findings represent the first insights of SST variability at <span class="hlt">seasonal</span> time scales for these two climate episodes in northwest Scotland.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AtmEn.180..234R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AtmEn.180..234R"><span>Trends in airborne pollen and pollen-<span class="hlt">season</span>-related features of anemophilous species in Jaen (south Spain): A 23-year perspective</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ruiz-Valenzuela, Luis; Aguilera, Fátima</p> <p>2018-05-01</p> <p>Over the last few decades, global <span class="hlt">warming</span> is prompting phenological changes in numerous plant species across Europe, and a trend towards rising airborne pollen concentrations has been detected. This study, focused on the most frequent pollen types from arboreal and herbaceous species in the airborne spectrum of Jaen (southern Spain), revealed significant changes in airborne pollen intensity and duration of the pollen <span class="hlt">season</span> over the 23-year study period. Here Cupressaceae, Olea, Pinus, Platanus, Quercus as arboreal taxa and Plantago as herbaceous taxa were the most important with notable changes of at least three pollen <span class="hlt">season</span> characteristics. Airborne pollen trends from arboreal taxa with high to very high allergenic potential are rising in line with the local temperature increasing trend, and their pollen <span class="hlt">seasons</span> tend to end later and last longer. However, both the pollen concentrations and the duration of the pollen <span class="hlt">season</span> of some herbaceous taxa are declining. The climate conditions projected for south Europe under different greenhouse emissions scenarios could continue to prompt greater pollen release and longer pollen <span class="hlt">season</span> in tree species, especially those that flowering in winter and early spring, but these <span class="hlt">warming</span> trends might be adverse for the local development of some herbaceous species and favorable for others sharing the same ecological niche. If similar <span class="hlt">warming</span> trends accompany long-term climate change, greater exposure times to <span class="hlt">seasonal</span> allergens may occur with subsequent effects on health.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27976819','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27976819"><span><span class="hlt">Warming</span> and provenance limit tree recruitment across and beyond the elevation range of subalpine forest.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kueppers, Lara M; Conlisk, Erin; Castanha, Cristina; Moyes, Andrew B; Germino, Matthew J; de Valpine, Perry; Torn, Margaret S; Mitton, Jeffry B</p> <p>2017-06-01</p> <p>Climate niche models project that subalpine forest ranges will extend upslope with climate <span class="hlt">warming</span>. These projections assume that the climate suitable for adult trees will be adequate for forest regeneration, ignoring climate requirements for seedling recruitment, a potential demographic bottleneck. Moreover, local genetic adaptation is expected to facilitate range expansion, with tree populations at the upper forest edge providing the seed best adapted to the alpine. Here, we test these expectations using a novel combination of common gardens, seeded with two widely distributed subalpine conifers, and climate manipulations replicated at three elevations. Infrared heaters raised temperatures in heated plots, but raised temperatures more in the forest than at or above treeline because strong winds at high elevation reduced heating efficiency. Watering increased <span class="hlt">season</span>-average soil moisture similarly across sites. Contrary to expectations, <span class="hlt">warming</span> reduced Engelmann spruce recruitment at and above treeline, as well as in the forest. <span class="hlt">Warming</span> reduced limber pine first-year recruitment in the forest, but had no net effect on fourth-year recruitment at any site. Watering during the snow-free <span class="hlt">season</span> alleviated some negative effects of <span class="hlt">warming</span>, indicating that <span class="hlt">warming</span> exacerbated water limitations. Contrary to expectations of local adaptation, low-elevation seeds of both species initially recruited more strongly than high-elevation seeds across the elevation gradient, although the low-provenance advantage diminished by the fourth year for Engelmann spruce, likely due to small sample sizes. High- and low-elevation provenances responded similarly to <span class="hlt">warming</span> across sites for Engelmann spruce, but differently for limber pine. In the context of increasing tree mortality, lower recruitment at all elevations with <span class="hlt">warming</span>, combined with lower quality, high-provenance seed being most available for colonizing the alpine, portends range contraction for Engelmann spruce. The lower</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1439219-warming-provenance-limit-tree-recruitment-across-beyond-elevation-range-subalpine-forest','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1439219-warming-provenance-limit-tree-recruitment-across-beyond-elevation-range-subalpine-forest"><span><span class="hlt">Warming</span> and provenance limit tree recruitment across and beyond the elevation range of subalpine forest</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Kueppers, Lara M.; Conlisk, Erin; Castanha, Cristina; ...</p> <p>2016-12-15</p> <p>Climate niche models project that subalpine forest ranges will extend upslope with climate <span class="hlt">warming</span>. These projections assume that the climate suitable for adult trees will be adequate for forest regeneration, ignoring climate requirements for seedling recruitment, a potential demographic bottleneck. Moreover, local genetic adaptation is expected to facilitate range expansion, with tree populations at the upper forest edge providing the seed best adapted to the alpine. Here, we test these expectations using a novel combination of common gardens, seeded with two widely distributed subalpine conifers, and climate manipulations replicated at three elevations. Infrared heaters raised temperatures in heated plots, butmore » raised temperatures more in the forest than at or above treeline because strong winds at high elevation reduced heating efficiency. Watering increased <span class="hlt">season</span>-average soil moisture similarly across sites. Contrary to expectations, <span class="hlt">warming</span> reduced Engelmann spruce recruitment at and above treeline, as well as in the forest. <span class="hlt">Warming</span> reduced limber pine first-year recruitment in the forest, but had no net effect on fourth-year recruitment at any site. Watering during the snow-free <span class="hlt">season</span> alleviated some negative effects of <span class="hlt">warming</span>, indicating that <span class="hlt">warming</span> exacerbated water limitations. Contrary to expectations of local adaptation, low-elevation seeds of both species initially recruited more strongly than high-elevation seeds across the elevation gradient, although the low-provenance advantage diminished by the fourth year for Engelmann spruce, likely due to small sample sizes. High- and low-elevation provenances responded similarly to <span class="hlt">warming</span> across sites for Engelmann spruce, but differently for limber pine. In the context of increasing tree mortality, lower recruitment at all elevations with <span class="hlt">warming</span>, combined with lower quality, high-provenance seed being most available for colonizing the alpine, portends range contraction for Engelmann spruce. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1439219','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1439219"><span><span class="hlt">Warming</span> and provenance limit tree recruitment across and beyond the elevation range of subalpine forest</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Kueppers, Lara M.; Conlisk, Erin; Castanha, Cristina</p> <p></p> <p>Climate niche models project that subalpine forest ranges will extend upslope with climate <span class="hlt">warming</span>. These projections assume that the climate suitable for adult trees will be adequate for forest regeneration, ignoring climate requirements for seedling recruitment, a potential demographic bottleneck. Moreover, local genetic adaptation is expected to facilitate range expansion, with tree populations at the upper forest edge providing the seed best adapted to the alpine. Here, we test these expectations using a novel combination of common gardens, seeded with two widely distributed subalpine conifers, and climate manipulations replicated at three elevations. Infrared heaters raised temperatures in heated plots, butmore » raised temperatures more in the forest than at or above treeline because strong winds at high elevation reduced heating efficiency. Watering increased <span class="hlt">season</span>-average soil moisture similarly across sites. Contrary to expectations, <span class="hlt">warming</span> reduced Engelmann spruce recruitment at and above treeline, as well as in the forest. <span class="hlt">Warming</span> reduced limber pine first-year recruitment in the forest, but had no net effect on fourth-year recruitment at any site. Watering during the snow-free <span class="hlt">season</span> alleviated some negative effects of <span class="hlt">warming</span>, indicating that <span class="hlt">warming</span> exacerbated water limitations. Contrary to expectations of local adaptation, low-elevation seeds of both species initially recruited more strongly than high-elevation seeds across the elevation gradient, although the low-provenance advantage diminished by the fourth year for Engelmann spruce, likely due to small sample sizes. High- and low-elevation provenances responded similarly to <span class="hlt">warming</span> across sites for Engelmann spruce, but differently for limber pine. In the context of increasing tree mortality, lower recruitment at all elevations with <span class="hlt">warming</span>, combined with lower quality, high-provenance seed being most available for colonizing the alpine, portends range contraction for Engelmann spruce. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010073054&hterms=warm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dwarm','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010073054&hterms=warm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dwarm"><span>Assimilation of GOES Land Surface Data Within a Rapid Update Cycle Format: Impact on MM5 <span class="hlt">Warm</span> <span class="hlt">Season</span> QPF</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lapenta, William M.; Suggs, Ron; Jedlovec, Gary; McNider, Richard T.; Dembek, Scott; Arnold, James E. (Technical Monitor)</p> <p>2001-01-01</p> <p> temperatures for all cycles on each day. The LRUC will be used during the 2001 summer <span class="hlt">months</span> to identify the impact of the assimilation on <span class="hlt">warm</span> <span class="hlt">season</span> QPF Results will be presented at the meeting.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70043248','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70043248"><span>Exceptional <span class="hlt">warming</span> in the Western Pacific-Indian Ocean <span class="hlt">warm</span> pool has contributed to more frequent droughts in eastern Africa</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Funk, Christopher C.; Peterson, Thomas C.; Stott, Peter A.; Herring, Stephanie</p> <p>2012-01-01</p> <p>In 2011, East Africa faced a tragic food crisis that led to famine conditions in parts of Somalia and severe food shortages in parts of Ethiopia and Somalia. While many nonclimatic factors contributed to this crisis (high global food prices, political instability, and chronic poverty, among others) failed rains in both the boreal winter of 2010/11 and the boreal spring of 2011 played a critical role. The back-to-back failures of these rains, which were linked to the dominant La Niña climate and <span class="hlt">warm</span> SSTs in the central and southeastern Indian Ocean, were particularly problematic since they followed poor rainfall during the spring and summer of 2008 and 2009. In fact, in parts of East Africa, in recent years, there has been a substantial increase in the number of below-normal rainy <span class="hlt">seasons</span>, which may be related to the <span class="hlt">warming</span> of the western Pacific and Indian Oceans (for more details, see Funk et al. 2008; Williams and Funk 2011; Williams et al. 2011; Lyon and DeWitt 2012). The basic argument of this work is that recent <span class="hlt">warming</span> in the Indian–Pacific <span class="hlt">warm</span> pool (IPWP) enhances the export of geopotential height energy from the <span class="hlt">warm</span> pool, which tends to produce subsidence across eastern Africa and reduce onshore moisture transports. The general pattern of this disruption has been supported by canonical correlation analyzes and numerical experiments with the Community Atmosphere Model (Funk et al. 2008), diagnostic evaluations of reanalysis data (Williams and Funk 2011; Williams et al. 2011), and SST-driven experiments with ECHAM4.5, ECHAM5, and the Community Climate Model version 3 (CCM3.6) (Lyon and DeWitt 2012).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ClDy...44.3281P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ClDy...44.3281P"><span>Analysis of rainfall <span class="hlt">seasonality</span> from observations and climate models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pascale, Salvatore; Lucarini, Valerio; Feng, Xue; Porporato, Amilcare; Hasson, Shabeh ul</p> <p>2015-06-01</p> <p>Two new indicators of rainfall <span class="hlt">seasonality</span> based on information entropy, the relative entropy (RE) and the dimensionless <span class="hlt">seasonality</span> index (DSI), together with the mean annual rainfall, are evaluated on a global scale for recently updated precipitation gridded datasets and for historical simulations from coupled atmosphere-ocean general circulation models. The RE provides a measure of the number of wet <span class="hlt">months</span> and, for precipitation regimes featuring a distinct wet and dry <span class="hlt">season</span>, it is directly related to the duration of the wet <span class="hlt">season</span>. The DSI combines the rainfall intensity with its degree of <span class="hlt">seasonality</span> and it is an indicator of the extent of the global monsoon region. We show that the RE and the DSI are fairly independent of the time resolution of the precipitation data, thereby allowing objective metrics for model intercomparison and ranking. Regions with different precipitation regimes are classified and characterized in terms of RE and DSI. Comparison of different land observational datasets reveals substantial difference in their local representation of <span class="hlt">seasonality</span>. It is shown that two-dimensional maps of RE provide an easy way to compare rainfall <span class="hlt">seasonality</span> from various datasets and to determine areas of interest. Models participating to the Coupled Model Intercomparison Project platform, Phase 5, consistently overestimate the RE over tropical Latin America and underestimate it in West Africa, western Mexico and East Asia. It is demonstrated that positive RE biases in a general circulation model are associated with excessively peaked <span class="hlt">monthly</span> precipitation fractions, too large during the wet <span class="hlt">months</span> and too small in the <span class="hlt">months</span> preceding and following the wet <span class="hlt">season</span>; negative biases are instead due, in most cases, to an excess of rainfall during the premonsoonal <span class="hlt">months</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP51C1074S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP51C1074S"><span><span class="hlt">Seasonally</span>-resolved trace element concentrations in stalagmites from a shallow cave in New Mexico</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sekhon, N.; Banner, J.; Miller, N. R.; Carlson, P. E.; Breecker, D.</p> <p>2017-12-01</p> <p>High-resolution (sub-annual/<span class="hlt">seasonal</span>) paleoclimate records extending beyond the instrumental period are required to test climate models and better understand how climate <span class="hlt">warming</span>/cooling and wetting/drying are manifested <span class="hlt">seasonally</span>. This is particularly the case for areas such as the southwest United States where precipitation and temperature <span class="hlt">seasonality</span> dictate the regional climate. Study of a 20thcentury stalagmite (Carlson et al., in prep) documented (1) <span class="hlt">seasonal</span> variation in trace element compositions of a stalagmite from a shallow, well-ventilated cave and (2) demonstrated the <span class="hlt">seasonal</span> variation in stalagmite Mg to be in agreement with predicted temperature-dependent fractionation between water and calcite. The <span class="hlt">seasonal</span> nature of variability was constrained by monitoring the cave on a <span class="hlt">monthly</span> basis (Casteel and Banner, 2015; Carlson et al., in prep). Here we expand on using stalagmites from shallow, well-ventilated caves as archives of <span class="hlt">seasonally</span>-resolved climate recorders by studying trace element variations in two coeval modern stalagmites (SBFC-1 and SBFC-2) cored from Sitting Bull Falls, southern New Mexico. <span class="hlt">Seasonal</span> cycles will be confirmed by analyzing Mg, Ba, and Sr in in-situ calcite precipitated on artificial substrates as available (July, Sept., and Nov. 2017). The chronology is constrained by semi-automated peak counting and 14C bomb-peak. In addition, principal component analyses of trace element data identify two primary underlying modes of trace element variability for soil-derived elements (Cu, Zn, and Fe) and bedrock-derived elements (Mg, Sr, and Ba). We hypothesize that the soil-derived elements are transported by <span class="hlt">seasonal</span> infiltration of organic colloids and the bedrock-derived elements are ­­controlled by variability in cave air temperature, drip water, and calcite growth rate. The two modes of variability will be calibrated against instrumental data over the 20th century. When complete, these new <span class="hlt">seasonally</span> resolved proxy records will</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1324273-impacts-manaus-pollution-plume-microphysical-properties-amazonian-warm-phase-clouds-wet-season','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1324273-impacts-manaus-pollution-plume-microphysical-properties-amazonian-warm-phase-clouds-wet-season"><span>Impacts of the Manaus pollution plume on the microphysical properties of Amazonian <span class="hlt">warm</span>-phase clouds in the wet <span class="hlt">season</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Cecchini, Micael A.; Machado, Luiz A. T.; Comstock, Jennifer M.; ...</p> <p>2016-06-09</p> <p>The remote atmosphere over the Amazon can be similar to oceanic regions in terms of aerosol conditions and cloud type formations. This is especially true during the wet <span class="hlt">season</span>. The main aerosol-related disturbances over the Amazon have both natural sources, such as dust transport from Africa, and anthropogenic sources, such as biomass burning or urban pollution. The present work considers the impacts of the latter on the microphysical properties of <span class="hlt">warm</span>-phase clouds by analyzing observations of the interactions between the Manaus pollution plume and its surroundings, as part of the GoAmazon2014/5 Experiment. The analyzed period corresponds to the wet seasonmore » (specifically from February to March 2014 and corresponding to the first Intensive Operating Period (IOP1) of GoAmazon2014/5). The droplet size distributions reported are in the range 1 µm ≤ D ≤ 50 µm in order to capture the processes leading up to the precipitation formation. The wet <span class="hlt">season</span> largely presents a clean background atmosphere characterized by frequent rain showers. As such, the contrast between background clouds and those affected by the Manaus pollution can be observed and detailed. The focus is on the characteristics of the initial microphysical properties in cumulus clouds predominantly at their early stages. The pollution-affected clouds are found to have smaller effective diameters and higher droplet number concentrations. The differences range from 10 to 40 % for the effective diameter and are as high as 1000% for droplet concentration for the same vertical levels. The growth rates of droplets with altitude are slower for pollution-affected clouds (2.90 compared to 5.59 µm km –1), as explained by the absence of bigger droplets at the onset of cloud development. Clouds under background conditions have higher concentrations of larger droplets (> 20 µm) near the cloud base, which would contribute significantly to the growth rates through the collision–coalescence process. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1324273','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1324273"><span>Impacts of the Manaus pollution plume on the microphysical properties of Amazonian <span class="hlt">warm</span>-phase clouds in the wet <span class="hlt">season</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Cecchini, Micael A.; Machado, Luiz A. T.; Comstock, Jennifer M.</p> <p></p> <p>The remote atmosphere over the Amazon can be similar to oceanic regions in terms of aerosol conditions and cloud type formations. This is especially true during the wet <span class="hlt">season</span>. The main aerosol-related disturbances over the Amazon have both natural sources, such as dust transport from Africa, and anthropogenic sources, such as biomass burning or urban pollution. The present work considers the impacts of the latter on the microphysical properties of <span class="hlt">warm</span>-phase clouds by analyzing observations of the interactions between the Manaus pollution plume and its surroundings, as part of the GoAmazon2014/5 Experiment. The analyzed period corresponds to the wet seasonmore » (specifically from February to March 2014 and corresponding to the first Intensive Operating Period (IOP1) of GoAmazon2014/5). The droplet size distributions reported are in the range 1 µm ≤ D ≤ 50 µm in order to capture the processes leading up to the precipitation formation. The wet <span class="hlt">season</span> largely presents a clean background atmosphere characterized by frequent rain showers. As such, the contrast between background clouds and those affected by the Manaus pollution can be observed and detailed. The focus is on the characteristics of the initial microphysical properties in cumulus clouds predominantly at their early stages. The pollution-affected clouds are found to have smaller effective diameters and higher droplet number concentrations. The differences range from 10 to 40 % for the effective diameter and are as high as 1000% for droplet concentration for the same vertical levels. The growth rates of droplets with altitude are slower for pollution-affected clouds (2.90 compared to 5.59 µm km –1), as explained by the absence of bigger droplets at the onset of cloud development. Clouds under background conditions have higher concentrations of larger droplets (> 20 µm) near the cloud base, which would contribute significantly to the growth rates through the collision–coalescence process. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JMS....79..134R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JMS....79..134R"><span>Identification, characteristics and <span class="hlt">seasonal</span> evolution of surface thermal fronts in the Argentinean Continental Shelf</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rivas, Andrés L.; Pisoni, Juan Pablo</p> <p>2010-01-01</p> <p>The location and <span class="hlt">seasonal</span> variability of surface thermal fronts along the Argentinean Continental Shelf (38-55°S) were studied using 18 years (1985-2002) of sea surface temperature (SST) satellite data. <span class="hlt">Monthly</span> SST gradients were calculated and a threshold was used to identify frontal pixels. Frontal areas were classified into 4 zones according to their <span class="hlt">seasonal</span> evolution and the main forcings leading to the front's formation were identified for each group. The shelf break front was easily detected due to the large number of frontal pixels in the region and its high mean gradient values. This front showed a marked annual cycle and relatively constant position associated to the bottom slope; it tended to be located where the core of the Malvinas current is closest to the shelf. Tidal fronts also showed a strong annual cycle, being detected in three well-defined regions during spring and summer. Along the coasts of Tierra del Fuego and Santa Cruz, the combination of strong tidal mixing and low-salinity coastal plumes led to semi-annual <span class="hlt">seasonal</span> cycles of frontal intensity and persistence that showed a relative maximum in winter. A similar behavior (semi-annual) was found at the coast off the Buenos Aires Province. There, the coastal dilution and the bathymetric gradient generated near-coastal fronts that changed direction <span class="hlt">seasonally</span>. In the northern mid-shelf, a front linked to the intrusion of <span class="hlt">warm</span> waters formed in the San Matías Gulf was identified during the winter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27862242','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27862242"><span><span class="hlt">Seasonal</span> mortality in zoo ruminants.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Carisch, Lea; Müller, Dennis W H; Hatt, Jean-Michel; Bingaman Lackey, Laurie; Rensch, E Eberhard; Clauss, Marcus; Zerbe, Philipp</p> <p>2017-01-01</p> <p>While <span class="hlt">seasonality</span> has often been investigated with respect to reproduction, <span class="hlt">seasonality</span> of mortality has received less attention. We investigated whether a <span class="hlt">seasonal</span> signal of mortality exists in wild ruminants kept in zoos, using data from 60,591 individuals of 88 species. We quantified the mortality in the 3 consecutive <span class="hlt">months</span> with the highest above-baseline mortality (3 MM). 3 MM was not related to relative life expectancy of species, indicating that <span class="hlt">seasonal</span> mortality does not necessarily impact husbandry success. Although 3 MM was mainly observed in autumn/winter <span class="hlt">months</span>, there was no evidence for an expected negative relationship with the latitude of the species' natural habitat and no positive relationship between 3 MM and the mean temperature in that habitat, indicating no evidence for species from lower latitudes/warmer climates being more susceptible to <span class="hlt">seasonal</span> mortality under zoo conditions. 3 MM was related to reproductive biology, with <span class="hlt">seasonally</span> reproducing species also displaying more <span class="hlt">seasonal</span> mortality. This pattern differed between groups: In cervids, the onset of <span class="hlt">seasonal</span> mortality appeared linked to the onset of rut in both sexes. This was less evident in bovids, where in a number of species (especially caprids), the onset of female <span class="hlt">seasonal</span> mortality was linked to the lambing period. While showing that the origin of a species from warmer climate zones does not constrain husbandry success in ruminants in terms of an increased <span class="hlt">seasonal</span> mortality, the results suggest that husbandry measures aimed at protecting females from rutting males are important, especially in cervids. Zoo Biol. 36:74-86, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatSR...516738C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatSR...516738C"><span>Climatic <span class="hlt">warming</span> and the future of bison as grazers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Craine, Joseph M.; Towne, E. Gene; Miller, Mary; Fierer, Noah</p> <p>2015-11-01</p> <p>Climatic <span class="hlt">warming</span> is likely to exacerbate nutritional stress and reduce weight gain in large mammalian herbivores by reducing plant nutritional quality. Yet accurate predictions of the effects of climatic <span class="hlt">warming</span> on herbivores are limited by a poor understanding of how herbivore diet varies along climate gradients. We utilized DNA metabarcoding to reconstruct <span class="hlt">seasonal</span> variation in the diet of North American bison (Bison bison) in two grasslands that differ in mean annual temperature by 6 °C. Here, we show that associated with greater nutritional stress in warmer climates, bison consistently consumed fewer graminoids and more shrubs and forbs, i.e. eudicots. Bison in the warmer grassland consumed a lower proportion of C3 grass, but not a greater proportion of C4 grass. Instead, bison diet in the warmer grassland had a greater proportion of N2-fixing eudicots, regularly comprising >60% of their protein intake in spring and fall. Although bison have been considered strict grazers, as climatic <span class="hlt">warming</span> reduces grass protein concentrations, bison may have to attempt to compensate by grazing less and browsing more. Promotion of high-protein, palatable eudicots or increasing the protein concentrations of grasses will be critical to minimizing <span class="hlt">warming</span>-imposed nutritional stress for bison and perhaps other large mammalian herbivores.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29103077','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29103077"><span>Dispersion of atmospheric air pollution in summer and winter <span class="hlt">season</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cichowicz, Robert; Wielgosiński, Grzegorz; Fetter, Wojciech</p> <p>2017-11-04</p> <p><span class="hlt">Seasonal</span> variation of air pollution is associated with variety of <span class="hlt">seasons</span> and specificity of particular <span class="hlt">months</span> which form the so-called summer and winter <span class="hlt">season</span> also known as the "heating" <span class="hlt">season</span>. The occurrence of higher values of air pollution in different <span class="hlt">months</span> of a year is associated with the type of climate, and accordingly with different atmospheric conditions in particular <span class="hlt">months</span>, changing state of weather on a given day, and anthropogenic activity. The appearance of these conditions results in different levels of air pollution characteristic for a given period. The study uses data collected during a seven-year period (2009-2015) in the automatic measuring station of immissions located in Eastern Wielkopolska. The analysis concerns the average and maximum values of air pollution (i.e., particulate matter PM10, sulfur dioxide, nitrogen dioxide, carbon monoxide, and ozone) from the perspective of their occurrence in particular <span class="hlt">seasons</span> and <span class="hlt">months</span> or in relation to meteorological actors such as temperature, humidity, and wind speed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120010334','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120010334"><span>Observational Analysis of Cloud and Precipitation in Midlatitude Cyclones: Northern Versus Southern Hemisphere <span class="hlt">Warm</span> Fronts</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Naud, Catherine M.; Posselt, Derek J.; van den Heever, Susan C.</p> <p>2012-01-01</p> <p>Extratropical cyclones are responsible for most of the precipitation and wind damage in the midlatitudes during the cold <span class="hlt">season</span>, but there are still uncertainties on how they will change in a <span class="hlt">warming</span> climate. An ubiquitous problem amongst General Circulation Models (GCMs) is a lack of cloudiness over the southern oceans that may be in part caused by a lack of clouds in cyclones. We analyze CloudSat, CALIPSO and AMSR-E observations for 3 austral and boreal cold <span class="hlt">seasons</span> and composite cloud frequency of occurrence and precipitation at the <span class="hlt">warm</span> fronts for northern and southern hemisphere oceanic cyclones. We find that cloud frequency of occurrence and precipitation rate are similar in the early stage of the cyclone life cycle in both northern and southern hemispheres. As cyclones evolve and reach their mature stage, cloudiness and precipitation at the <span class="hlt">warm</span> front increase in the northern hemisphere but decrease in the southern hemisphere. This is partly caused by lower amounts of precipitable water being available to southern hemisphere cyclones, and smaller increases in wind speed as the cyclones evolve. Southern hemisphere cloud occurrence at the <span class="hlt">warm</span> front is found to be more sensitive to the amount of moisture in the <span class="hlt">warm</span> sector than to wind speeds. This suggests that cloudiness in southern hemisphere storms may be more susceptible to changes in atmospheric water vapor content, and thus to changes in surface temperature than their northern hemisphere counterparts. These differences between northern and southern hemisphere cyclones are statistically robust, indicating A-Train-based analyses as useful tools for evaluation of GCMs in the next IPCC report.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27145698','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27145698"><span>Plant phenological synchrony increases under rapid within-spring <span class="hlt">warming</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Cong; Tang, Yanhong; Chen, Jin</p> <p>2016-05-05</p> <p>Phenological synchrony influences many ecological processes. Recent climate change has altered the synchrony of phenology, but little is known about the underlying mechanisms. Here using in situ phenological records from Europe, we found that the standard deviation (SD, as a measure of synchrony) of first leafing day (FLD) and the SD of first flowering day (FFD) among local plants were significantly smaller in the years and/or in the regions with a more rapid within-spring <span class="hlt">warming</span> speed (WWS, the linear slope of the daily mean temperature against the days during spring, in (o)C/day) with correlation coefficients of -0.75 and -0.48 for FLD and -0.55 and -0.23 for FFD. We further found that the SDs of temperature sensitivity of local plants were smaller under the rapid WWS conditions with correlation coefficients of -0.46 and -0.33 for FLD and FFD respectively. This study provides the first evidence that the within-<span class="hlt">season</span> rate of change of the temperature but not the magnitude determines plant phenological synchrony. It implies that temporally, the asymmetric <span class="hlt">seasonal</span> climatic <span class="hlt">warming</span> may decrease the synchrony via increasing WWS, especially in arctic regions; spatially, plants in coastal and low latitude areas with low WWS would have more diverse spring phenological traits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25543547','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25543547"><span>The influence of <span class="hlt">season</span> and living environment on children's urinary 1-hydroxypyrene levels in Ulaanbaatar, Mongolia.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Yi-Ting; Huang, Yu-Kai; Luvsan, Munkh-Erdene; Gombojav, Enkhjargal; Ochir, Chimedsuren; Bulgan, Jargal; Chan, Chang-Chuan</p> <p>2015-02-01</p> <p>Heating indoor living environments elevates air pollution in Ulaanbaatar, Mongolia. This study was conducted to investigate the influence of <span class="hlt">season</span> and living environment on children's urinary 1-hydroxypyrene (1-OHP) levels in Ulaanbaatar, Mongolia. Our study subjects were 320 children aged 11-15 years living in gers, brick houses and apartments, in ger and non-ger areas of Ulaanbaatar. Spot urine samples and questionnaires were collected three times from each subject in three <span class="hlt">seasons</span>, September (<span class="hlt">warm</span>) and December (cold) in 2011 and March (moderate) in 2012. Urinary 1-OHP was analyzed by high-performance liquid chromatography with fluorescent detection (HPLC/FLD). Generalized estimating equation (GEE) models were applied to estimate the <span class="hlt">seasonal</span> and residential effects on 1-OHP levels, adjusting for demographic and environmental factors. Children's urinary 1-OHP levels showed significant <span class="hlt">seasonal</span> differences with 0.30 ± 0.57 μmol/mol creatinine in cold <span class="hlt">season</span>, 0.14 ± 0.12 μmol/mol creatinine in moderate <span class="hlt">season</span>, and 0.14 ± 0.21 μmol/mol creatinine in <span class="hlt">warm</span> <span class="hlt">season</span>. After controlling confounding factors, the GEE model showed that <span class="hlt">season</span>, living area, and housing type had significant influence on children's urinary 1-OHP levels. Urinary 1-OHP levels in the cold and moderate <span class="hlt">seasons</span> were, respectively 2.13 and 1.37 times higher than the <span class="hlt">warm</span> <span class="hlt">season</span>. Urinary 1-OHP levels for children living in ger areas were 1.27 times higher than those living in non-ger areas. Children who lived in gers or brick houses had 1.58 and 1.34 times higher 1-OHP levels, respectively, compared with those living in apartments. Children's urinary 1-OHP levels were associated with either estimated NO2 or SO2 concentrations at their home addresses in Ulaanbaatar. Mongolian children's urinary 1-OHP levels were significantly elevated during the cold <span class="hlt">season</span>, and for those living in ger areas, gers, or brick houses in Ulaanbaatar. Children's urinary 1-OHP levels were associated PAH co</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoRL..4410654L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoRL..4410654L"><span>Revisiting the Cause of the 1989-2009 Arctic Surface <span class="hlt">Warming</span> Using the Surface Energy Budget: Downward Infrared Radiation Dominates the Surface Fluxes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Sukyoung; Gong, Tingting; Feldstein, Steven B.; Screen, James A.; Simmonds, Ian</p> <p>2017-10-01</p> <p>The Arctic has been <span class="hlt">warming</span> faster than elsewhere, especially during the cold <span class="hlt">season</span>. According to the leading theory, ice-albedo feedback <span class="hlt">warms</span> the Arctic Ocean during the summer, and the heat gained by the ocean is released during the winter, causing the cold-<span class="hlt">season</span> <span class="hlt">warming</span>. Screen and Simmonds (2010; SS10) concluded that the theory is correct by comparing trend patterns in surface air temperature (SAT), surface turbulence heat flux (HF), and net surface infrared radiation (IR). However, in this comparison, downward IR is more appropriate to use. By analyzing the same data used in SS10 using the surface energy budget, it is shown here that over most of the Arctic the skin temperature trend, which closely resembles the SAT trend, is largely accounted for by the downward IR, not the HF, trend.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014HESS...18..367T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014HESS...18..367T"><span>Coupled prediction of flood response and debris flow initiation during <span class="hlt">warm</span>- and cold-<span class="hlt">season</span> events in the Southern Appalachians, USA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tao, J.; Barros, A. P.</p> <p>2014-01-01</p> <p>Debris flows associated with rainstorms are a frequent and devastating hazard in the Southern Appalachians in the United States. Whereas <span class="hlt">warm-season</span> events are clearly associated with heavy rainfall intensity, the same cannot be said for the cold-<span class="hlt">season</span> events. Instead, there is a relationship between large (cumulative) rainfall events independently of <span class="hlt">season</span>, and thus hydrometeorological regime, and debris flows. This suggests that the dynamics of subsurface hydrologic processes play an important role as a trigger mechanism, specifically through soil moisture redistribution by interflow. We further hypothesize that the transient mass fluxes associated with the temporal-spatial dynamics of interflow govern the timing of shallow landslide initiation, and subsequent debris flow mobilization. The first objective of this study is to investigate this relationship. The second objective is to assess the physical basis for a regional coupled flood prediction and debris flow warning system. For this purpose, uncalibrated model simulations of well-documented debris flows in headwater catchments of the Southern Appalachians using a 3-D surface-groundwater hydrologic model coupled with slope stability models are examined in detail. Specifically, we focus on two vulnerable headwater catchments that experience frequent debris flows, the Big Creek and the Jonathan Creek in the Upper Pigeon River Basin, North Carolina, and three distinct weather systems: an extremely heavy summertime convective storm in 2011; a persistent winter storm lasting several days; and a severe winter storm in 2009. These events were selected due to the optimal availability of rainfall observations; availability of detailed field surveys of the landslides shortly after they occurred, which can be used to evaluate model predictions; and because they are representative of events that cause major economic losses in the region. The model results substantiate that interflow is a useful prognostic of conditions</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" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.B33H..03P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.B33H..03P"><span>Photoperiod- and <span class="hlt">Warming</span>-driven Phenological Changes and Carbon and Nutrient Cycling. Remote Sensing Assessment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Penuelas, J.; Fu, Y.; Estiarte, M.; Gamon, J. A.; Filella, I.; Verger, A.; Jannssens, I.</p> <p>2017-12-01</p> <p>Ongoing spring <span class="hlt">warming</span> allows the growing <span class="hlt">season</span> to begin earlier in northern ecosystems, thus enhancing their carbon uptake. We will present data on atmospheric CO2 concentration measurements to show that this spring advancement of annual carbon intake in response to <span class="hlt">warming</span> is decreasing. Reduced chilling during dormancy and the interactions between temperature and photoperiod in driving leaf-out may play a role. We will show that short photoperiod (in <span class="hlt">warm</span> springs when leaf-out is early) significantly increases the heat requirement for leaf-out whereas long photoperiod (in cold springs when leaf-out is late) reduces the heat requirement for leaf-out. These two contrasting photoperiod effects illustrate a complicated temperature response of leaf-out phenology. We will also discuss how photoperiod exerts a strict control on leaf senescence at latitudes where winters are severe and temperature gains importance in the regulation as winters become less severe. On average, climatic <span class="hlt">warming</span> will delay and drought will advance leaf senescence, but at varying degrees depending on the species. <span class="hlt">Warming</span> and drought thus have opposite effects on the phenology of leaf senescence, and the impact of climate change will therefore depend on the relative importance of each factor in specific regions. We will then discuss the ecological effects of these phenological changes focusing, as an example, on the impacts of changes on the phenology of leaf senescence on carbon uptake and nutrient cycling. Finally, we will present recent advances on remote sensing monitoring of both the phenological changes and their ecological impacts. We will focus on advances derived from a close correspondence between <span class="hlt">seasonally</span> changing foliar pigment levels, expressed as chlorophyll/carotenoid ratios, and evergreen photosynthetic activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4226490','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4226490"><span>Large Impacts of Climatic <span class="hlt">Warming</span> on Growth of Boreal Forests since 1960</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kauppi, Pekka E.; Posch, Maximilian; Pirinen, Pentti</p> <p>2014-01-01</p> <p>Boreal forests are sensitive to climatic <span class="hlt">warming</span>, because low temperatures hold back ecosystem processes, such as the mobilization of nitrogen in soils. A greening of the boreal landscape has been observed using remote sensing, and the <span class="hlt">seasonal</span> amplitude of CO2 in the northern hemisphere has increased, indicating <span class="hlt">warming</span> effects on ecosystem productivity. However, field observations on responses of ecosystem productivity have been lacking on a large sub-biome scale. Here we report a significant increase in the annual growth of boreal forests in Finland in response to climatic <span class="hlt">warming</span>, especially since 1990. This finding is obtained by linking meteorological records and forest inventory data on an area between 60° and 70° northern latitude. An additional increase in growth has occurred in response to changes in other drivers, such as forest management, nitrogen deposition and/or CO2 concentration. A similar <span class="hlt">warming</span> impact can be expected in the entire boreal zone, where <span class="hlt">warming</span> takes place. Given the large size of the boreal biome – more than ten million km2– important climate feedbacks are at stake, such as the future carbon balance, transpiration and albedo. PMID:25383552</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25383552','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25383552"><span>Large impacts of climatic <span class="hlt">warming</span> on growth of boreal forests since 1960.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kauppi, Pekka E; Posch, Maximilian; Pirinen, Pentti</p> <p>2014-01-01</p> <p>Boreal forests are sensitive to climatic <span class="hlt">warming</span>, because low temperatures hold back ecosystem processes, such as the mobilization of nitrogen in soils. A greening of the boreal landscape has been observed using remote sensing, and the <span class="hlt">seasonal</span> amplitude of CO2 in the northern hemisphere has increased, indicating <span class="hlt">warming</span> effects on ecosystem productivity. However, field observations on responses of ecosystem productivity have been lacking on a large sub-biome scale. Here we report a significant increase in the annual growth of boreal forests in Finland in response to climatic <span class="hlt">warming</span>, especially since 1990. This finding is obtained by linking meteorological records and forest inventory data on an area between 60° and 70° northern latitude. An additional increase in growth has occurred in response to changes in other drivers, such as forest management, nitrogen deposition and/or CO2 concentration. A similar <span class="hlt">warming</span> impact can be expected in the entire boreal zone, where <span class="hlt">warming</span> takes place. Given the large size of the boreal biome - more than ten million km2- important climate feedbacks are at stake, such as the future carbon balance, transpiration and albedo.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC43J..07G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC43J..07G"><span>Increasing frequency and duration of Arctic winter <span class="hlt">warming</span> events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Graham, R. M.; Cohen, L.; Petty, A.; Boisvert, L.; Rinke, A.; Hudson, S. R.; Nicolaus, M.; Granskog, M. A.</p> <p>2017-12-01</p> <p>Record low Arctic sea ice extents were observed during the last three winter <span class="hlt">seasons</span> (March). During each of these winters, near-surface air temperatures close to 0°C were observed, in situ, over sea ice in the central Arctic. Recent media reports and scientific studies suggest that such winter <span class="hlt">warming</span> events were unprecedented for the Arctic. Here we use in situ winter (December-March) temperature observations, such as those from Soviet North Pole drifting stations and ocean buoys, to determine how common Arctic winter <span class="hlt">warming</span> events are. The earliest record we find of a winter <span class="hlt">warming</span> event was in March 1896, where a temperature of -3.7˚C was observed at 84˚N during the Fram expedition. Observations of winter <span class="hlt">warming</span> events exist over most of the Arctic Basin. Despite a limited observational network, temperatures exceeding -5°C were measured in situ during more than 30% of winters from 1954 to 2010, by either North Pole drifting stations or ocean buoys. Correlation coefficients between the atmospheric reanalysis, ERA-Interim, and these in-situ temperature records are shown to be on the order of 0.90. This suggests that ERA-Interim is a suitable tool for studying Arctic winter <span class="hlt">warming</span> events. Using the ERA-Interim record (1979-2016), we show that the North Pole (NP) region typically experiences 10 <span class="hlt">warming</span> events (T2m > -10°C) per winter, compared with only five in the Pacific Central Arctic (PCA). We find a positive trend in the overall duration of winter <span class="hlt">warming</span> events for both the NP region (4.25 days/decade) and PCA (1.16 days/decade), due to an increased number of events of longer duration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4946780','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4946780"><span>Effects of <span class="hlt">Seasonal</span> Weather on Breeding Phenology and Reproductive Success of Alpine Ptarmigan in Colorado</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wann, Gregory T.; Aldridge, Cameron L.; Braun, Clait E.</p> <p>2016-01-01</p> <p>Animal populations occurring at high elevations are often assumed to be in peril of extinctions or local extirpations due to elevational-dispersal limitations and thermoregulatory constraints as habitats change and <span class="hlt">warm</span>. However, long-term monitoring of high-elevation populations is uncommon relative to those occurring at lower elevations, and evidence supporting this assumption is limited. We analyzed 45 years of reproductive data for two Colorado populations of white-tailed ptarmigan (Lagopus leucura), an alpine-endemic species with restricted distribution in western North America. <span class="hlt">Seasonal</span> temperatures measured by the number of growing degree days <span class="hlt">warmed</span> significantly at our study sites for pre-nesting, nesting, and brood-rearing <span class="hlt">seasonal</span> periods (mean advance of 8 growing degree days per decade), and both populations advanced their reproductive phenology over the study period based on median hatch dates (median advance of 3.7 and 1.9 days per decade for the northern and southern sites, respectively). Reproductive performance measured by the number of chicks per hen declined significantly at one study site but not the other, and differences between sites may have been due to habitat degradation at one study area. Annual variability in chicks per hen was large at both sites but only weakly related to <span class="hlt">seasonal</span> weather. An index of precipitation and temperature during the brood-rearing period was the best predictor for reproductive success with <span class="hlt">warm</span> and dry conditions relating positively to number of chicks per hen. Our results provide evidence for two alpine ptarmigan populations that are remarkably invariant to fluctuations in <span class="hlt">seasonal</span> weather with respect to reproductive success as measured by number of chicks per hen in the breeding population. These results are surprising given the general perception of alpine animal populations as being highly sensitive to <span class="hlt">warming</span> temperatures. PMID:27420478</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27420478','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27420478"><span>Effects of <span class="hlt">Seasonal</span> Weather on Breeding Phenology and Reproductive Success of Alpine Ptarmigan in Colorado.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wann, Gregory T; Aldridge, Cameron L; Braun, Clait E</p> <p>2016-01-01</p> <p>Animal populations occurring at high elevations are often assumed to be in peril of extinctions or local extirpations due to elevational-dispersal limitations and thermoregulatory constraints as habitats change and <span class="hlt">warm</span>. However, long-term monitoring of high-elevation populations is uncommon relative to those occurring at lower elevations, and evidence supporting this assumption is limited. We analyzed 45 years of reproductive data for two Colorado populations of white-tailed ptarmigan (Lagopus leucura), an alpine-endemic species with restricted distribution in western North America. <span class="hlt">Seasonal</span> temperatures measured by the number of growing degree days <span class="hlt">warmed</span> significantly at our study sites for pre-nesting, nesting, and brood-rearing <span class="hlt">seasonal</span> periods (mean advance of 8 growing degree days per decade), and both populations advanced their reproductive phenology over the study period based on median hatch dates (median advance of 3.7 and 1.9 days per decade for the northern and southern sites, respectively). Reproductive performance measured by the number of chicks per hen declined significantly at one study site but not the other, and differences between sites may have been due to habitat degradation at one study area. Annual variability in chicks per hen was large at both sites but only weakly related to <span class="hlt">seasonal</span> weather. An index of precipitation and temperature during the brood-rearing period was the best predictor for reproductive success with <span class="hlt">warm</span> and dry conditions relating positively to number of chicks per hen. Our results provide evidence for two alpine ptarmigan populations that are remarkably invariant to fluctuations in <span class="hlt">seasonal</span> weather with respect to reproductive success as measured by number of chicks per hen in the breeding population. These results are surprising given the general perception of alpine animal populations as being highly sensitive to <span class="hlt">warming</span> temperatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70191680','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70191680"><span>Effects of <span class="hlt">seasonal</span> weather on breeding phenology and reproductive success of alpine ptarmigan in Colorado</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wann, Greg; Aldridge, Cameron L.; Braun, Clait E.</p> <p>2016-01-01</p> <p>Animal populations occurring at high elevations are often assumed to be in peril of extinctions or local extirpations due to elevational-dispersal limitations and thermoregulatory constraints as habitats change and <span class="hlt">warm</span>. However, long-term monitoring of high-elevation populations is uncommon relative to those occurring at lower elevations, and evidence supporting this assumption is limited. We analyzed 45 years of reproductive data for two Colorado populations of white-tailed ptarmigan (Lagopus leucura), an alpine-endemic species with restricted distribution in western North America. <span class="hlt">Seasonal</span> temperatures measured by the number of growing degree days <span class="hlt">warmed</span> significantly at our study sites for pre-nesting, nesting, and brood-rearing <span class="hlt">seasonal</span> periods (mean advance of 8 growing degree days per decade), and both populations advanced their reproductive phenology over the study period based on median hatch dates (median advance of 3.7 and 1.9 days per decade for the northern and southern sites, respectively). Reproductive performance measured by the number of chicks per hen declined significantly at one study site but not the other, and differences between sites may have been due to habitat degradation at one study area. Annual variability in chicks per hen was large at both sites but only weakly related to <span class="hlt">seasonal</span> weather. An index of precipitation and temperature during the brood-rearing period was the best predictor for reproductive success with <span class="hlt">warm</span> and dry conditions relating positively to number of chicks per hen. Our results provide evidence for two alpine ptarmigan populations that are remarkably invariant to fluctuations in <span class="hlt">seasonal</span> weather with respect to reproductive success as measured by number of chicks per hen in the breeding population. These results are surprising given the general perception of alpine animal populations as being highly sensitive to <span class="hlt">warming</span> temperatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4778439','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4778439"><span>Ocean acidification exerts negative effects during <span class="hlt">warming</span> conditions in a developing Antarctic fish</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Flynn, Erin E; Bjelde, Brittany E; Miller, Nathan A</p> <p>2015-01-01</p> <p>Abstract Anthropogenic CO2 is rapidly causing oceans to become warmer and more acidic, challenging marine ectotherms to respond to simultaneous changes in their environment. While recent work has highlighted that marine fishes, particularly during early development, can be vulnerable to ocean acidification, we lack an understanding of how life-history strategies, ecosystems and concurrent ocean <span class="hlt">warming</span> interplay with interspecific susceptibility. To address the effects of multiple ocean changes on cold-adapted, slowly developing fishes, we investigated the interactive effects of elevated partial pressure of carbon dioxide (pCO2) and temperature on the embryonic physiology of an Antarctic dragonfish (Gymnodraco acuticeps), with protracted embryogenesis (∼10 <span class="hlt">months</span>). Using an integrative, experimental approach, our research examined the impacts of near-future <span class="hlt">warming</span> [−1 (ambient) and 2°C (+3°C)] and ocean acidification [420 (ambient), 650 (moderate) and 1000 μatm pCO2 (high)] on survival, development and metabolic processes over the course of 3 weeks in early development. In the presence of increased pCO2 alone, embryonic mortality did not increase, with greatest overall survival at the highest pCO2. Furthermore, embryos were significantly more likely to be at a later developmental stage at high pCO2 by 3 weeks relative to ambient pCO2. However, in combined <span class="hlt">warming</span> and ocean acidification scenarios, dragonfish embryos experienced a dose-dependent, synergistic decrease in survival and developed more slowly. We also found significant interactions between temperature, pCO2 and time in aerobic enzyme activity (citrate synthase). Increased temperature alone increased whole-organism metabolic rate (O2 consumption) and developmental rate and slightly decreased osmolality at the cost of increased mortality. Our findings suggest that developing dragonfish are more sensitive to ocean <span class="hlt">warming</span> and may experience negative physiological effects of ocean</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27293718','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27293718"><span>Ocean acidification exerts negative effects during <span class="hlt">warming</span> conditions in a developing Antarctic fish.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Flynn, Erin E; Bjelde, Brittany E; Miller, Nathan A; Todgham, Anne E</p> <p>2015-01-01</p> <p>Anthropogenic CO2 is rapidly causing oceans to become warmer and more acidic, challenging marine ectotherms to respond to simultaneous changes in their environment. While recent work has highlighted that marine fishes, particularly during early development, can be vulnerable to ocean acidification, we lack an understanding of how life-history strategies, ecosystems and concurrent ocean <span class="hlt">warming</span> interplay with interspecific susceptibility. To address the effects of multiple ocean changes on cold-adapted, slowly developing fishes, we investigated the interactive effects of elevated partial pressure of carbon dioxide (pCO2) and temperature on the embryonic physiology of an Antarctic dragonfish (Gymnodraco acuticeps), with protracted embryogenesis (∼10 <span class="hlt">months</span>). Using an integrative, experimental approach, our research examined the impacts of near-future <span class="hlt">warming</span> [-1 (ambient) and 2°C (+3°C)] and ocean acidification [420 (ambient), 650 (moderate) and 1000 μatm pCO2 (high)] on survival, development and metabolic processes over the course of 3 weeks in early development. In the presence of increased pCO2 alone, embryonic mortality did not increase, with greatest overall survival at the highest pCO2. Furthermore, embryos were significantly more likely to be at a later developmental stage at high pCO2 by 3 weeks relative to ambient pCO2. However, in combined <span class="hlt">warming</span> and ocean acidification scenarios, dragonfish embryos experienced a dose-dependent, synergistic decrease in survival and developed more slowly. We also found significant interactions between temperature, pCO2 and time in aerobic enzyme activity (citrate synthase). Increased temperature alone increased whole-organism metabolic rate (O2 consumption) and developmental rate and slightly decreased osmolality at the cost of increased mortality. Our findings suggest that developing dragonfish are more sensitive to ocean <span class="hlt">warming</span> and may experience negative physiological effects of ocean acidification only in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020034756','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020034756"><span>Enhanced Climatic <span class="hlt">Warming</span> in the Tibetan Plateau Due to Double CO2: A Model Study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chen, Baode; Chao, Winston C.; Liu, Xiao-Dong; Lau, William K. M. (Technical Monitor)</p> <p>2001-01-01</p> <p>The NCAR (National Center for Atmospheric Research) regional climate model (RegCM2) with time-dependent lateral meteorological fields provided by a 130-year transient increasing CO2 simulation of the NCAR Climate System Model (CSM) has been used to investigate the mechanism of enhanced ground temperature <span class="hlt">warming</span> over the TP (Tibetan Plateau). From our model results, a remarkable tendency of <span class="hlt">warming</span> increasing with elevation is found for the winter <span class="hlt">season</span>, and elevation dependency of <span class="hlt">warming</span> is not clearly recognized in the summer <span class="hlt">season</span>. This simulated feature of elevation dependency of ground temperature is consistent with observations. Based on an analysis of surface energy budget, the short wave solar radiation absorbed at the surface plus downward long wave flux reaching the surface shows a strong elevation dependency, and is mostly responsible for enhanced surface <span class="hlt">warming</span> over the TP. At lower elevations, the precipitation forced by topography is enhanced due to an increase in water vapor supply resulted from a <span class="hlt">warming</span> in the atmosphere induced by doubling CO2. This precipitation enhancement must be associated with an increase in clouds, which results in a decline in solar flux reaching surface. At higher elevations, large snow depletion is detected in the 2xCO2run. It leads to a decrease in albedo, therefore more solar flux is absorbed at the surface. On the other hand, much more uniform increase in downward long wave flux reaching the surface is found. The combination of these effects (i.e. decrease in solar flux at lower elevations, increase in solar flux at higher elevation and more uniform increase in downward long wave flux) results in elevation dependency of enhanced ground temperature <span class="hlt">warming</span> over the TP.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018E%26ES..121e2028F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018E%26ES..121e2028F"><span>The comparative analysis of pre-flood <span class="hlt">season</span> precipitation and water vapor transportation over guangdong before and after “Hiatus”</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fan, Lingli</p> <p>2018-02-01</p> <p>Relation between pre-flood <span class="hlt">season</span> precipitation and water vapor transport in Guangdong was analysed by using the <span class="hlt">monthly</span> observed precipitation data, reanalysis data of ERA, NCEP/NCAR, and OAFlux during 1979-2015, and the differences between before/after global <span class="hlt">warming</span> “hiatus” were studied. Results showed that, after “hiatus”, during the pre-flood <span class="hlt">season</span>, skin-temperature, evaporation, and the absolute humidity over the ocean near to Southern China was decreasing, and over land was increasing. So, the water cycle over the ocean had slowed down and over land had speed up. The absolute humidity difference between the ocean and the land was reduced. However, at the same time, the total wind speed in Southern China had decreased. So, the water vapor transport from the ocean to the land had reduced. The Eastern Guangdong had an anomalous convergence of meridional water vapor transport, led to increased precipitation; but in Western Guangdong, there was no meridional water vapor transport, so precipitation had a decrease.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ClDy...45.1673V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ClDy...45.1673V"><span>Projected changes in Malawi's growing <span class="hlt">season</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vizy, Edward K.; Cook, Kerry H.; Chimphamba, James; McCusker, Brent</p> <p>2015-09-01</p> <p>Regional climate model projections at 30-km resolution are used to predict future mid-century and late-century growing <span class="hlt">season</span> changes over Malawi due to global <span class="hlt">warming</span> under the Representative Concentration Pathway 8.5 business-as-usual emissions forcing scenario. Three different methods for estimating growing <span class="hlt">season</span> characteristics are applied and evaluated. All three methods yield reasonable growing <span class="hlt">season</span> length, onset, and demise date estimates over Malawi given the wide range of uncertainty of the observations. The projections indicate the likelihood for a shorter growing <span class="hlt">season</span> in the future over Malawi south of 13.5°S. At mid-century the growing <span class="hlt">season</span> length is predicted to be 20-40 % (20-55 days) shorter over the southernmost districts and 5-20 % (5-30 days) shorter over the central districts. By late-century the length is predicted to be 25-55 % (20-70 days) shorter with significant differences extending into northern Malawi. The shorter growing <span class="hlt">season</span> is primarily associated with an earlier demise date, as no significant change in the onset date is predicted. Analysis of the regional circulation and horizontal moisture flux transport indicates that the earlier demise is associated with an intensification of the thermal low over the Kalahari Desert to the south and west of Malawi and an expansion of the mid-tropospheric Kalahari anticyclone over southern Africa. The stronger thermal low/anticyclone enhances the moisture flux divergence over Malawi suppressing the convective activity at the end of the wet <span class="hlt">season</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70190161','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70190161"><span>Effects of experimentally reduced snowpack and passive <span class="hlt">warming</span> on montane meadow plant phenology and floral resources</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sherwood, J.A.; Debinski, D.M.; Caragea, P.C.; Germino, Matthew</p> <p>2017-01-01</p> <p>Climate change can have a broad range of effects on ecosystems and organisms, and early responses may include shifts in vegetation phenology and productivity that may not coincide with the energetics and forage timing of higher trophic levels. We evaluated phenology, annual height growth, and foliar frost responses of forbs to a factorial experiment of snow removal (SR) and <span class="hlt">warming</span> in a high-elevation meadow over two years in the Rocky Mountains, United States. Species included arrowleaf balsamroot (Balsamorhiza sagittata, early-<span class="hlt">season</span> emergence and flowering) and buckwheat (Eriogonum umbellatum, semi-woody and late-<span class="hlt">season</span> flowering), key forbs for pollinator and nectar-using animal communities that are widely distributed and locally abundant in western North America. Snow removal exerted stronger effects than did <span class="hlt">warming</span>, and advanced phenology differently for each species. Specifically, SR advanced green-up by a few days for B. sagittata to >2 wk in E. umbellatum, and led to 5- to 11-d advances in flowering of B. sagittata in one year and advances in bud break in 3 of 4 species/yr combinations. Snow removal increased height of E. umbellatum appreciably (~5 cm added to ~22.8 cm in control), but led to substantial increases in frost damage to flowers of B. sagittata. Whereas <span class="hlt">warming</span> had no effects on E. umbellatum, it increased heights of B. sagittata by >6 cm (compared to 30.7 cm in control plots) and moreover led to appreciable reductions in frost damage to flowers. These data suggest that timing of snowmelt, which is highly variable from year to year but is advancing in recent decades, has a greater impact on these critical phenological, growth, and floral survival traits and floral/nectar resources than <span class="hlt">warming</span> per se, although <span class="hlt">warming</span> mitigated early effects of SR on frost kill of flowers. Given the short growing <span class="hlt">season</span> of these species, the shifts could cause uncoupling in nectar availability and timing of foraging.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4878477','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4878477"><span>Predicting the evolutionary dynamics of <span class="hlt">seasonal</span> adaptation to novel climates in Arabidopsis thaliana</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fournier-Level, Alexandre; Perry, Emily O.; Wang, Jonathan A.; Braun, Peter T.; Migneault, Andrew; Cooper, Martha D.; Metcalf, C. Jessica E.; Schmitt, Johanna</p> <p>2016-01-01</p> <p>Predicting whether and how populations will adapt to rapid climate change is a critical goal for evolutionary biology. To examine the genetic basis of fitness and predict adaptive evolution in novel climates with <span class="hlt">seasonal</span> variation, we grew a diverse panel of the annual plant Arabidopsis thaliana (multiparent advanced generation intercross lines) in controlled conditions simulating four climates: a present-day reference climate, an increased-temperature climate, a winter-<span class="hlt">warming</span> only climate, and a poleward-migration climate with increased photoperiod amplitude. In each climate, four successive <span class="hlt">seasonal</span> cohorts experienced dynamic daily temperature and photoperiod variation over a year. We measured 12 traits and developed a genomic prediction model for fitness evolution in each <span class="hlt">seasonal</span> environment. This model was used to simulate evolutionary trajectories of the base population over 50 y in each climate, as well as 100-y scenarios of gradual climate change following adaptation to a reference climate. Patterns of plastic and evolutionary fitness response varied across <span class="hlt">seasons</span> and climates. The increased-temperature climate promoted genetic divergence of subpopulations across <span class="hlt">seasons</span>, whereas in the winter-<span class="hlt">warming</span> and poleward-migration climates, <span class="hlt">seasonal</span> genetic differentiation was reduced. In silico “resurrection experiments” showed limited evolutionary rescue compared with the plastic response of fitness to <span class="hlt">seasonal</span> climate change. The genetic basis of adaptation and, consequently, the dynamics of evolutionary change differed qualitatively among scenarios. Populations with fewer founding genotypes and populations with genetic diversity reduced by prior selection adapted less well to novel conditions, demonstrating that adaptation to rapid climate change requires the maintenance of sufficient standing variation. PMID:27140640</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27140640','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27140640"><span>Predicting the evolutionary dynamics of <span class="hlt">seasonal</span> adaptation to novel climates in Arabidopsis thaliana.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fournier-Level, Alexandre; Perry, Emily O; Wang, Jonathan A; Braun, Peter T; Migneault, Andrew; Cooper, Martha D; Metcalf, C Jessica E; Schmitt, Johanna</p> <p>2016-05-17</p> <p>Predicting whether and how populations will adapt to rapid climate change is a critical goal for evolutionary biology. To examine the genetic basis of fitness and predict adaptive evolution in novel climates with <span class="hlt">seasonal</span> variation, we grew a diverse panel of the annual plant Arabidopsis thaliana (multiparent advanced generation intercross lines) in controlled conditions simulating four climates: a present-day reference climate, an increased-temperature climate, a winter-<span class="hlt">warming</span> only climate, and a poleward-migration climate with increased photoperiod amplitude. In each climate, four successive <span class="hlt">seasonal</span> cohorts experienced dynamic daily temperature and photoperiod variation over a year. We measured 12 traits and developed a genomic prediction model for fitness evolution in each <span class="hlt">seasonal</span> environment. This model was used to simulate evolutionary trajectories of the base population over 50 y in each climate, as well as 100-y scenarios of gradual climate change following adaptation to a reference climate. Patterns of plastic and evolutionary fitness response varied across <span class="hlt">seasons</span> and climates. The increased-temperature climate promoted genetic divergence of subpopulations across <span class="hlt">seasons</span>, whereas in the winter-<span class="hlt">warming</span> and poleward-migration climates, <span class="hlt">seasonal</span> genetic differentiation was reduced. In silico "resurrection experiments" showed limited evolutionary rescue compared with the plastic response of fitness to <span class="hlt">seasonal</span> climate change. The genetic basis of adaptation and, consequently, the dynamics of evolutionary change differed qualitatively among scenarios. Populations with fewer founding genotypes and populations with genetic diversity reduced by prior selection adapted less well to novel conditions, demonstrating that adaptation to rapid climate change requires the maintenance of sufficient standing variation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3780896','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3780896"><span>Sea surface height evidence for long-term <span class="hlt">warming</span> effects of tropical cyclones on the ocean</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mei, Wei; Primeau, François; McWilliams, James C.; Pasquero, Claudia</p> <p>2013-01-01</p> <p>Tropical cyclones have been hypothesized to influence climate by pumping heat into the ocean, but a direct measure of this <span class="hlt">warming</span> effect is still lacking. We quantified cyclone-induced ocean <span class="hlt">warming</span> by directly monitoring the thermal expansion of water in the wake of cyclones, using satellite-based sea surface height data that provide a unique way of tracking the changes in ocean heat content on <span class="hlt">seasonal</span> and longer timescales. We find that the long-term effect of cyclones is to <span class="hlt">warm</span> the ocean at a rate of 0.32 ± 0.15 PW between 1993 and 2009, i.e., ∼23 times more efficiently per unit area than the background equatorial <span class="hlt">warming</span>, making cyclones potentially important modulators of the climate by affecting heat transport in the ocean–atmosphere system. Furthermore, our analysis reveals that the rate of <span class="hlt">warming</span> increases with cyclone intensity. This, together with a predicted shift in the distribution of cyclones toward higher intensities as climate <span class="hlt">warms</span>, suggests the ocean will get even warmer, possibly leading to a positive feedback. PMID:23922393</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23922393','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23922393"><span>Sea surface height evidence for long-term <span class="hlt">warming</span> effects of tropical cyclones on the ocean.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mei, Wei; Primeau, François; McWilliams, James C; Pasquero, Claudia</p> <p>2013-09-17</p> <p>Tropical cyclones have been hypothesized to influence climate by pumping heat into the ocean, but a direct measure of this <span class="hlt">warming</span> effect is still lacking. We quantified cyclone-induced ocean <span class="hlt">warming</span> by directly monitoring the thermal expansion of water in the wake of cyclones, using satellite-based sea surface height data that provide a unique way of tracking the changes in ocean heat content on <span class="hlt">seasonal</span> and longer timescales. We find that the long-term effect of cyclones is to <span class="hlt">warm</span> the ocean at a rate of 0.32 ± 0.15 PW between 1993 and 2009, i.e., ∼23 times more efficiently per unit area than the background equatorial <span class="hlt">warming</span>, making cyclones potentially important modulators of the climate by affecting heat transport in the ocean-atmosphere system. Furthermore, our analysis reveals that the rate of <span class="hlt">warming</span> increases with cyclone intensity. This, together with a predicted shift in the distribution of cyclones toward higher intensities as climate <span class="hlt">warms</span>, suggests the ocean will get even warmer, possibly leading to a positive feedback.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H12A..01B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H12A..01B"><span>Conditional <span class="hlt">Monthly</span> Weather Resampling Procedure for Operational <span class="hlt">Seasonal</span> Water Resources Forecasting</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beckers, J.; Weerts, A.; Tijdeman, E.; Welles, E.; McManamon, A.</p> <p>2013-12-01</p> <p>To provide reliable and accurate <span class="hlt">seasonal</span> streamflow forecasts for water resources management several operational hydrologic agencies and hydropower companies around the world use the Extended Streamflow Prediction (ESP) procedure. The ESP in its original implementation does not accommodate for any additional information that the forecaster may have about expected deviations from climatology in the near future. Several attempts have been conducted to improve the skill of the ESP forecast, especially for areas which are affected by teleconnetions (e,g. ENSO, PDO) via selection (Hamlet and Lettenmaier, 1999) or weighting schemes (Werner et al., 2004; Wood and Lettenmaier, 2006; Najafi et al., 2012). A disadvantage of such schemes is that they lead to a reduction of the signal to noise ratio of the probabilistic forecast. To overcome this, we propose a resampling method conditional on climate indices to generate meteorological time series to be used in the ESP. The method can be used to generate a large number of meteorological ensemble members in order to improve the statistical properties of the ensemble. The effectiveness of the method was demonstrated in a real-time operational hydrologic <span class="hlt">seasonal</span> forecasts system for the Columbia River basin operated by the Bonneville Power Administration. The forecast skill of the k-nn resampler was tested against the original ESP for three basins at the long-range <span class="hlt">seasonal</span> time scale. The BSS and CRPSS were used to compare the results to those of the original ESP method. Positive forecast skill scores were found for the resampler method conditioned on different indices for the prediction of spring peak flows in the Dworshak and Hungry Horse basin. For the Libby Dam basin however, no improvement of skill was found. The proposed resampling method is a promising practical approach that can add skill to ESP forecasts at the <span class="hlt">seasonal</span> time scale. Further improvement is possible by fine tuning the method and selecting the most</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017CliPa..13.1037C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017CliPa..13.1037C"><span>Atmospheric circulation and hydroclimate impacts of alternative <span class="hlt">warming</span> scenarios for the Eocene</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carlson, Henrik; Caballero, Rodrigo</p> <p>2017-08-01</p> <p>Recent work in modelling the <span class="hlt">warm</span> climates of the early Eocene shows that it is possible to obtain a reasonable global match between model surface temperature and proxy reconstructions, but only by using extremely high atmospheric CO2 concentrations or more modest CO2 levels complemented by a reduction in global cloud albedo. Understanding the mix of radiative forcing that gave rise to Eocene warmth has important implications for constraining Earth's climate sensitivity, but progress in this direction is hampered by the lack of direct proxy constraints on cloud properties. Here, we explore the potential for distinguishing among different radiative forcing scenarios via their impact on regional climate changes. We do this by comparing climate model simulations of two end-member scenarios: one in which the climate is <span class="hlt">warmed</span> entirely by CO2 (which we refer to as the greenhouse gas (GHG) scenario) and another in which it is <span class="hlt">warmed</span> entirely by reduced cloud albedo (which we refer to as the <q>low CO2-thin clouds</q> or LCTC scenario) . The two simulations have an almost identical global-mean surface temperature and equator-to-pole temperature difference, but the LCTC scenario has ˜ 11 % greater global-mean precipitation than the GHG scenario. The LCTC scenario also has cooler midlatitude continents and warmer oceans than the GHG scenario and a tropical climate which is significantly more El Niño-like. Extremely high <span class="hlt">warm-season</span> temperatures in the subtropics are mitigated in the LCTC scenario, while cool-<span class="hlt">season</span> temperatures are lower at all latitudes. These changes appear large enough to motivate further, more detailed study using other climate models and a more realistic set of modelling assumptions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1392226','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1392226"><span>A zero-power <span class="hlt">warming</span> chamber for investigating plant responses to rising temperature</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Lewin, Keith F.; McMahon, Andrew M.; Ely, Kim S.</p> <p></p> <p>Advances in understanding and model representation of plant and ecosystem responses to rising temperature have typically required temperature manipulation of research plots, particularly when considering <span class="hlt">warming</span> scenarios that exceed current climate envelopes. In remote or logistically challenging locations, passive <span class="hlt">warming</span> using solar radiation is often the only viable approach for temperature manipulation. But, current passive <span class="hlt">warming</span> approaches are only able to elevate the mean daily air temperature by ~1.5 °C. Motivated by our need to understand temperature acclimation in the Arctic, where <span class="hlt">warming</span> has been markedly greater than the global average and where future <span class="hlt">warming</span> is projected to be ~2–3more » °C by the middle of the century; we have developed an alternative approach to passive <span class="hlt">warming</span>. Our zero-power <span class="hlt">warming</span> (ZPW) chamber requires no electrical power for fully autonomous operation. It uses a novel system of internal and external heat exchangers that allow differential actuation of pistons in coupled cylinders to control chamber venting. This enables the ZPW chamber venting to respond to the difference between the external and internal air temperatures, thereby increasing the potential for <span class="hlt">warming</span> and eliminating the risk of overheating. During the thaw <span class="hlt">season</span> on the coastal tundra of northern Alaska our ZPW chamber was able to elevate the mean daily air temperature 2.6 °C above ambient, double the <span class="hlt">warming</span> achieved by an adjacent passively <span class="hlt">warmed</span> control chamber that lacked our hydraulic system. We describe the construction, evaluation and performance of our ZPW chamber and discuss the impact of potential artefacts associated with the design and its operation on the Arctic tundra. Our approach is highly flexible and tunable, enabling customization for use in many different environments where significantly greater temperature manipulation than that possible with existing passive <span class="hlt">warming</span> approaches is desired.« 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. Their policies may differ from this site.</div> </div><!-- container --> <footer><a id="backToTop" href="#top"> </a><nav><a id="backToTop" href="#top"> </a><ul class="links"><a id="backToTop" href="#top"> </a><li><a id="backToTop" href="#top"></a><a href="/sitemap.html">Site Map</a></li> <li><a href="/members/index.html">Members Only</a></li> <li><a href="/website-policies.html">Website Policies</a></li> <li><a href="https://doe.responsibledisclosure.com/hc/en-us" target="_blank">Vulnerability Disclosure Program</a></li> <li><a href="/contact.html">Contact Us</a></li> </ul> <div class="small">Science.gov is maintained by the U.S. Department of Energy's <a href="https://www.osti.gov/" target="_blank">Office of Scientific and Technical Information</a>, in partnership with <a href="https://www.cendi.gov/" target="_blank">CENDI</a>.</div> </nav> </footer> <script type="text/javascript"><!-- // var lastDiv = ""; function showDiv(divName) { // hide last div if (lastDiv) { document.getElementById(lastDiv).className = "hiddenDiv"; } //if value of the box is not nothing and an object with that name exists, then change the class if (divName && document.getElementById(divName)) { document.getElementById(divName).className = "visibleDiv"; lastDiv = divName; } } //--> </script> <script> /** * Function that tracks a click on an outbound link in Google Analytics. * This function takes a valid URL string as an argument, and uses that URL string * as the event label. */ var trackOutboundLink = function(url,collectionCode) { try { h = window.open(url); setTimeout(function() { ga('send', 'event', 'topic-page-click-through', collectionCode, url); }, 1000); } catch(err){} }; </script> <!-- Google Analytics --> <script> (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o), m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) })(window,document,'script','//www.google-analytics.com/analytics.js','ga'); ga('create', 'UA-1122789-34', 'auto'); ga('send', 'pageview'); </script> <!-- End Google Analytics --> <script> showDiv('page_1') </script> </body> </html>