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Sample records for increased winter snowfall

  1. A major increase in winter snowfall during the middle Holocene on western Greenland caused by reduced sea ice in Baffin Bay and the Labrador Sea

    NASA Astrophysics Data System (ADS)

    Thomas, Elizabeth K.; Briner, Jason P.; Ryan-Henry, John J.; Huang, Yongsong

    2016-05-01

    Precipitation is predicted to increase in the Arctic as temperature increases and sea ice retreats. Yet the mechanisms controlling precipitation in the Arctic are poorly understood and quantified only by the short, sparse instrumental record. We use hydrogen isotope ratios (δ2H) of lipid biomarkers in lake sediments from western Greenland to reconstruct precipitation seasonality and summer temperature during the past 8 kyr. Aquatic biomarker δ2H was 100‰ more negative from 6 to 4 ka than during the early and late Holocene, which we interpret to reflect increased winter snowfall. The middle Holocene also had high summer air temperature, decreased early winter sea ice in Baffin Bay and the Labrador Sea, and a strong, warm West Greenland Current. These results corroborate model predictions of winter snowfall increases caused by sea ice retreat and furthermore suggest that warm currents advecting more heat into the polar seas may enhance Arctic evaporation and snowfall.

  2. Impact of increasing temperature on snowfall in Switzerland

    NASA Astrophysics Data System (ADS)

    Serquet, G.; Marty, C.; Rebetez, M.

    2012-04-01

    The exact impact of changing temperatures on snow amounts is extremely important for mountainous regions, not only for hydrological aspects but also for winter tourism and the leisure industry in winter ski resorts. However, the impact of increasing temperatures on snowfall amounts is difficult to measure because of the large natural variability of precipitation. In addition, the impact of increasing temperatures varies, depending on region and altitude. Moreover, the impact of the observed increasing trend in temperature on snowfall and snow cover has usually been investigated on a seasonal basis only. On a monthly basis, the relationship between this increase in temperature and snowfall is still largely unknown. Of particular concern are the autumn and spring months and variations with altitude. In order to isolate the impact of changing temperatures on snowfall from the impact of changes in the frequency and intensity of total precipitation, we analyzed the proportion of snowfall days compared to precipitation days for each month from November to April in Switzerland. Our analyses concern 52 meteorological stations located between 200 and 2700 m asl over a 48 year time span. Our results show clear decreasing trends in snowfall days relative to precipitation days for all months (November to April) during the study period 1961-2008. Moreover, the present conditions in December, January and February correspond to those measured in the 1960's in November and March. During the whole snow season, the snowfall ratios have been transferred in elevation by at least 300 m from 1961 to 2008. This means that with an expected temperature increase during the coming decades at least similar to the temperature rise of recent decades, we can assume an additional similar altitudinal transfer of the snowfall days relative to precipitation days ratios. The current situation in November and March could thus become the future situation in December, January and February. During the

  3. Dust Activity during Winter Time in East Asia and Snowfall Obervations and Simulations in Taiwan

    NASA Astrophysics Data System (ADS)

    Tsai, L.

    2013-12-01

    Taiwan has relatively frequent snowfall in mountain during winter among regions of the same latitude. The phenomenon is contributed by Taiwan's unique topography - high and steep mountains, and geographical location - sitting on the route the continental polar air mass travels from its birthplace to the ocean, contribute to this phenomenon. Snow occurence, in addition to the freezing-point temperature, when two requirements are met: sufficient vapor and the condensation nuclei in the air. This study pursues the causes of the snowfall activity in Taiwan, the relations between the East Asian dust aerosol and the snowfall activity in Taiwan, and the impacts the climate changes have on the snowfall activity in Taiwan. In this study, Yushan snowfall activity from 1995~2011 and related atmosphere circulations were examined using SYNOP data, NCEP/DOE reanalysis atmospheric data, the observations of the Central Weather Bureau's Yushan Weather Station and the Taiwan Air Quality Monitoring Network of the Environment Protect Administration, Executive Yuan. To provide a quantitative measure of snowfall events and dust activity, a snowfall activity index (SAI) and the DAI Index by Yu et al. (2010) were defined. The time series of yearly SAI and DAI show that East Asian dust storm activity and Taiwan snowfall marked interannual variations during 1995 ~ 2011. For active years such as 2008, 2010, and 2011, SAI was hundreds of times larger than that for inactive years such as 1996, 1999 and 2003; and DAI in active years such as 2001 and 2002 was several tens of times larger than that in inactive years such as 1997 and 2003. In active years when the EAT (East Asian Trough) was shifted eastward, the strength of WPH (West Pacific High) increased in the south and an anticyclone thus occurred. This anticyclone introduced anomalous southwesterly flows along the southeastern coast of mainland China and over Taiwan, resulting in a wetter-than-normal atmosphere in support of snowfall

  4. Winter Snowfall Turns an Emerald White

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Ireland's climate is normally mild due to the nearby Gulf Stream, but the waning days of 2000 saw the Emerald Isle's green fields swathed in an uncommon blanket of white. The contrast between summer and winter is apparent in this pair of images of southwestern Ireland acquired by MISR's vertical-viewing (nadir) camera on August 23, 2000 (left) and December 29, 2000 (right). The corresponding Terra orbit numbers are 3628 and 5492, respectively.

    The year 2000 brought record-breaking weather to the British Isles. England and Wales experienced the wettest spring and autumn months since 1766. Despite being one of the warmest years in recent history, a cold snap arrived between Christmas and New Year's Day. According to the UK Meteorological Office, the 18 centimeters (7 inches) of snow recorded at Aldergrove, Northern Ireland, on December 27-28 was the deepest daily fall since 1930.

    Prominent geographical features visible in the MISR images include Galway Bay near the top left. Further south, the mouth of the River Shannon, the largest river in the British Isles, meets the Atlantic Ocean. In the lower portions of the images are the counties of Limerick, Kerry and Cork.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology

  5. 21st century projections of snowfall and winter severity across central-eastern North America

    NASA Astrophysics Data System (ADS)

    Notaro, M.; Lorenz, D. J.; Hoving, C.; Schummer, M.

    2014-12-01

    Statistically downscaled climate projections from nine global climate models (GCMs) are used to force a snow accumulation and ablation model (SNOW-17) across the central-eastern North American Landscape Conservation Cooperatives (LCCs) to develop high-resolution projections of snowfall, snow depth, and winter severity index (WSI) by the mid- and late 21st century. Here, we use projections of a cumulative WSI (CWSI) known to influence autumn-winter waterfowl migration to demonstrate the utility of SNOW-17 results. The application of statistically downscaled climate data and a snow model leads to a better representation of lake processes in the Great Lakes Basin, topographic effects in the Appalachian Mountains, and spatial patterns of climatological snowfall, compared to the original GCMs. Annual mean snowfall is simulated to decline across the region, particularly in early winter (December-January), leading to a delay in the mean onset of the snow season. Due to a warming-induced acceleration of snowmelt, the percentage loss in snow depth exceeds that of snowfall. Across the Plains and Prairie Potholes LCC and Upper Midwest and Great Lakes LCC, daily snowfall events are projected to become less common, but more intense. The greatest reductions in the number of days per year with a present snowpack are expected close to the historical position of the -5°C isotherm in DJFM, around 44°N. The CWSI is projected to decline substantially during December-January, leading to increased likelihood of delays in timing and intensity of autumn-winter waterfowl migrations.

  6. Increased future ice discharge from Antarctica owing to higher snowfall.

    PubMed

    Winkelmann, R; Levermann, A; Martin, M A; Frieler, K

    2012-12-13

    Anthropogenic climate change is likely to cause continuing global sea level rise, but some processes within the Earth system may mitigate the magnitude of the projected effect. Regional and global climate models simulate enhanced snowfall over Antarctica, which would provide a direct offset of the future contribution to global sea level rise from cryospheric mass loss and ocean expansion. Uncertainties exist in modelled snowfall, but even larger uncertainties exist in the potential changes of dynamic ice discharge from Antarctica and thus in the ultimate fate of the precipitation-deposited ice mass. Here we show that snowfall and discharge are not independent, but that future ice discharge will increase by up to three times as a result of additional snowfall under global warming. Our results, based on an ice-sheet model forced by climate simulations through to the end of 2500 (ref. 8), show that the enhanced discharge effect exceeds the effect of surface warming as well as that of basal ice-shelf melting, and is due to the difference in surface elevation change caused by snowfall on grounded versus floating ice. Although different underlying forcings drive ice loss from basal melting versus increased snowfall, similar ice dynamical processes are nonetheless at work in both; therefore results are relatively independent of the specific representation of the transition zone. In an ensemble of simulations designed to capture ice-physics uncertainty, the additional dynamic ice loss along the coastline compensates between 30 and 65 per cent of the ice gain due to enhanced snowfall over the entire continent. This results in a dynamic ice loss of up to 1.25 metres in the year 2500 for the strongest warming scenario. The reported effect thus strongly counters a potential negative contribution to global sea level by the Antarctic Ice Sheet. PMID:23235878

  7. Winter snowfall and summer photosynthesis for the Great Basin Desert shrubs Artemisia tridentata and Purshia tridentata.

    NASA Astrophysics Data System (ADS)

    Loik, M. E.; Griffith, A. B.; Alpert, H.; Concilio, A. L.; Martinson, S. J.

    2011-12-01

    Snowfall provides the majority of soil water recharge in many western high-elevation North American ecosystems, but climate change may alter the magnitude and timing of snowfall and snow melt events thereby affecting ecosystem processes. Experiments were conducted to test hypotheses about multi-scale linkages of antecedent snow depth variation with soil water content and physiological performance of deeply-rooted shrubs in the western Great Basin Desert. Snow depth was manipulated using eight 50-year old snow fences near Mammoth Lakes, California, USA. Water potential and photosynthetic gas exchange were measured annually in early summer (1 - 2 mo following snowmelt), between 2004 and 2008 for Artemisia tridentata (Asteraceae) and Purshia tridentata (Rosaceae) on plots with increased ("+ snow"), decreased ("- snow") and ambient snow depth. Seasonal patterns were measured from May - September 2005, and four to five months after snowmelt in wet and dry years. Snow depth on +snow plots was about twice that of ambient-depth plots in most years. Depth was about 20% lower on -snow plots. Soil water content in May on +snow plots was roughly double that on ambient and 220% of that on -snow plots. Water potential patterns varied across daily, seasonal, and annual scales, but only on a few occasions was there a significant snow-depth effect. Stomatal conductance (gs) and CO2 assimilation (A) increased for several months after snowmelt in 2005, but there were only a few times when there was a snow depth effect. Photosynthetic gas exchange reflected inter-annual snow depth, but the magnitude of the variation was lower. There was a threshold response of A to October 1 - June 1 cumulative precipitation. For A. tridentata, A differed as a function of Snow Water Equivalents (SWE) across five years of measurements. Results suggest that plant water relations for these two deeply-rooted shrub species are resilient to variation in winter snow depth and subsequent spring soil water

  8. Reduced winter snowfall damages the structure and function of wintergreen ferns.

    PubMed

    Tessier, Jack T

    2014-05-20

    • Premise of the study: The full impact of climate change on ecosystems and the humans that depend on them is uncertain. Anthropogenic climate change is resulting in winters with less snow than is historically typical. This deficit may have an impact on wintergreen ferns whose fronds lie prostrate under the snowpack and are thereby protected from frost.• Methods: Frost damage and ecophysiological traits were quantified for three species of wintergreen fern (Dryopteris intermedia, Dryopteris marginalis, and Polystichum acrostichoides) near Delhi, NY following the winters of 2012 (which had very little snowfall) and 2013 (which had typical snowfall).• Key results: Dryopteris intermedia was the most common species and had the highest percentage of frost-damaged fronds and the highest percentage of its cover damaged in 2012. Frost damage was significantly less in 2013 for all species. Polystichum acrostichoides had the highest vernal photosynthetic rate in undamaged fronds, and all three species had a negative net photosynthetic rate in frost-damaged fronds. The wintergreen fern community lost 36.69 ± 2.80% of its productive surface area to frost damage in 2012. Dryopteris intermedia had the thinnest leaves and this trait may have made it the most susceptible to frost damage.• Conclusions: These results demonstrate that repeated winters of little snow may have a significant impact on the structure and functioning of the wintergreen fern community, and species will respond to a reduced snowpack on an individual basis. PMID:24844709

  9. Riming in winter alpine snowfall during CLACE 2014: polarimetric radar and in-situ observations

    NASA Astrophysics Data System (ADS)

    Grazioli, J.; Lloyd, G.; Panziera, L.; Connolly, P. J.; Henneberger, J.; Berne, A.

    2015-07-01

    This study investigates the microphysics of winter alpine snowfall occurring in mixed-phase clouds in an inner-Alpine valley during January and February 2014. The available observations include high resolution polarimetric radar and in-situ measurements of the ice-phase and liquid-phase components of clouds and precipitation. Radar-based hydrometeor classification suggests that riming is a dominant factor leading to an efficient growth of the precipitating mass and to a large snow accumulation on the ground. The time steps during which rimed precipitation is dominant are analysed in terms of temporal evolution and vertical structure. In most cases, riming is the result of a turbulent phase, of limited duration, during which supercooled liquid water (SLW) is available. When this turbulent layer is stable in time and continuously provides SLW, riming can be sustained for many hours without SLW depletion, thus generating large accumulations of snow. The microphysical interpretation as well as the meteorological situation associated with one event with those characteristics are detailed in the manuscript. The vertical structure of polarimetric radar observations during intense rimed precipitation shows a peculiar maximum of specific differential phase shift Kdp, associated with large number concentrations and/or heavy riming of anisotropic crystals. Below this Kdp peak there is usually an enhancement in ZH, proportional to the Kdp enhancement and interpreted as aggregation of ice crystals.

  10. Projected changes in snowfall extremes and interannual variability of snowfall in the western United States

    NASA Astrophysics Data System (ADS)

    Lute, A. C.; Abatzoglou, J. T.; Hegewisch, K. C.

    2015-02-01

    Projected warming will have significant impacts on snowfall accumulation and melt, with implications for water availability and management in snow-dominated regions. Changes in snowfall extremes are confounded by projected increases in precipitation extremes. Downscaled climate projections from 20 global climate models were bias-corrected to montane Snowpack Telemetry stations across the western United States to assess mid-21st century changes in the mean and variability of annual snowfall water equivalent (SFE) and extreme snowfall events, defined by the 90th percentile of cumulative 3 day SFE amounts. Declines in annual SFE and number of snowfall days were projected for all stations. Changes in the magnitude of snowfall event quantiles were sensitive to historical winter temperature. At climatologically cooler locations, such as in the Rocky Mountains, changes in the magnitude of snowfall events mirrored changes in the distribution of precipitation events, with increases in extremes and less change in more moderate events. By contrast, declines in snowfall event magnitudes were found for all quantiles in warmer locations. Common to both warmer and colder sites was a relative increase in the magnitude of snowfall extremes compared to annual SFE and a larger fraction of annual SFE from snowfall extremes. The coefficient of variation of annual SFE increased up to 80% in warmer montane regions due to projected declines in snowfall days and the increased contribution of snowfall extremes to annual SFE. In addition to declines in mean annual SFE, more frequent low-snowfall years and less frequent high-snowfall years were projected for every station.

  11. Twentieth century increase in snowfall in coastal West Antarctica

    NASA Astrophysics Data System (ADS)

    Thomas, E. R.; Hosking, J. S.; Tuckwell, R. R.; Warren, R. A.; Ludlow, E. C.

    2015-11-01

    The Amundsen Sea sector of the West Antarctic ice sheet has been losing mass in recent decades; however, long records of snow accumulation are needed to place the recent changes in context. Here we present 300 year records of snow accumulation from two ice cores drilled in Ellsworth Land, West Antarctica. The records show a dramatic increase in snow accumulation during the twentieth century, linked to a deepening of the Amundsen Sea Low (ASL), tropical sea surface temperatures, and large-scale atmospheric circulation. The observed increase in snow accumulation and interannual variability during the late twentieth century is unprecedented in the context of the past 300 years and evidence that the recent deepening of the ASL is part of a longer trend.

  12. CO_2 Snowfalls and Baroclinic Waves in the Northern Winter Polar Atmosphere of Mars

    NASA Astrophysics Data System (ADS)

    Kuroda, T.; Medvedev, A. S.; Kasaba, Y.; Hartogh, P.

    2013-09-01

    CO2 snow forms in the high-latitude atmosphere of Mars in regular patches coinciding with passages of baroclinic planetary waves (periodic oscillations of temperature and other meteorological fields). Our simulations using a Mars general circulation model (MGCM) show that about a half of the snow cover on the northern polar cap is created by such snowfalls. This discovery would allow to forecast snow storms in future robotic and manned missions to Mars [1].

  13. Simulated CO2 Snowfalls and Baroclinic Waves in the Northern Winter Polar Atmosphere on Mars: Feasibility of Forecasts

    NASA Astrophysics Data System (ADS)

    Kuroda, T.; Medvedev, A. S.; Kasaba, Y.; Hartogh, P.

    2013-12-01

    The seasonal CO2 polar cap is formed from ice particles that have fallen from the atmosphere as well as those condensed directly on the surface. The possible occurrence of CO2 snowfall in the winter polar regions have been observed, and previous simulation studies have indicated that the longitudinal irregularities of CO2 ice clouds in the northern polar region seemed to be linked to local weather phenomena. Transient planetary waves are the prominent dynamical feature during northern winters in the martian atmosphere, and this study focuses on revealing the mechanism of how the dynamical influence of transient planetary waves affects the occurrences of CO2 ice clouds, snowfalls and formations of seasonal CO2 polar cap in high latitudes during northern winters. The DRAMATIC (Dynamics, RAdiation, MAterial Transport and their mutual InteraCtions) MGCM, which is used for this study, is based on a Japanese terrestrial model (CCSR/NIES/FRCGC MIROC) with a spectral solver for the three-dimensional primitive equations. In this simulation the horizontal resolution is set at about 5.6° × 5.6° (~333 km at equator), the vertical grid consists of 69 σ-levels with the top of the model at about 100 km. Realistic topography, albedo, thermal inertia and roughness data for the Mars surface are included. Radiative effects of CO2 gas (considering only LTE) and dust, in solar and infrared wavelengths, are taken into account. We have implemented a simple scheme representing the formation and transport of CO2 ice clouds into our MGCM, and investigated snowfall in high latitudes during northern winters. The MGCM simulations showed that the CO2 ice clouds are formed at altitudes of up to ~40 km in the northern polar region (northward of 70° N) during winter, which is consistent with the observations (MRO-MCS and MGS-MOLA). In addition, we found that the occurrence of the CO2 ice clouds correlated to a large degree with the cold phases of transient planetary waves. In the altitudes

  14. Organic Characteristics of High Sierra Nevada Snowfall during the Winter of 2014

    NASA Astrophysics Data System (ADS)

    Antweiler, R.; Andrews, E. D.; Aiken, G.; Butler, K. D.

    2015-12-01

    During the winter of 2014 snow samples were collected from Tuolumne Meadows in Yosemite National Park (elevation 2600 m) for the determination of the organic constituents. Samples were collected from the middle of the snowpack during January - April (referred to as "snowpack" samples), from three depths in a cross-sectional pit dug in mid April ("snow pit" samples) and from fresh snow collected during two snowstorms ("snowstorm" samples). Samples were frozen immediately after collection in sealed glass containers and thawed just prior to analysis. The DOC concentration of snowpack samples varied from 0.9 - 1.7 mg C/L; the DOC of snowstorm samples had much lower values (0.3 - 0.4 mg C/L). DOC concentrations of snow taken from the top third of the snow pit in mid-April was much higher (6.6 mg C/L), but this sample had large amounts of "debris"; the snow samples from the middle and bottom of the snow pit had concentrations similar to the snowpack samples. Snows were fractionated into hydrophobic, transphilic and hydrophilic acid fractions (HPOA, TPIA and HPIA, respectively); HPOA comprised between 30 and 44% of the total, TPIA ranged from 8-16% and HPIA ranged from 19-28%. Samples collected from the snow pit at the end of the winter always had lower percentages of TPIA and HPIA than those taken from the snowpack during the winter. All snow samples were also analyzed for low molecular weight organic acids (LMWOA) via ion chromatography, and all samples contained trace amounts of formate, acetate and oxalate, with acetate generally being predominant. A few of the samples showed evidence of trace amounts of propionate and butyrate, but no other organic acids could be positively identified. If it is assumed that the LMWOA fraction consisted of the three anions above (acetate, formate and oxalate), then the percentage of the HPIA which was LMWOA ranged from 5-15% with uniformly higher percentages occurring in the snowpack samples than in the snow pit samples taken at the

  15. Spatial and Temporal Trends of Snowfall in Central New York - A Lake Effect Dominated Region

    NASA Astrophysics Data System (ADS)

    Hartnett, Justin Joseph

    Central New York is located in one of the snowiest regions in the United States, with the city of Syracuse, New York the snowiest metropolis in the nation. Snowfall in the region generally begins in mid-November and lasts until late-March. Snow accumulation occurs from a multitude of conditions: frontal systems, mid-latitude cyclones, Nor'easters, and most notably lake-effect storms. Lake effect snowfall (LES) is a difficult parameter to forecast due to the isolated and highly variable nature of the storm. Consequently, studies have attempted to determine changes in snowfall for lake-effect dominated regions. Annual snowfall patterns are of particular concern as seasonal snowfall totals are vital for water resources, winter businesses, agriculture, government and state agencies, and much more. Through the use of snowfall, temperature, precipitation, and location data from the National Weather Service's Cooperative Observer Program (COOP), spatial and temporal changes in snowfall for Central New York were determined. In order to determine climatic changes in snowfall, statistical analyses were performed (i.e. least squares estimation, correlations, principal component analyses, etc.) and spatial maps analyzed. Once snowfall trends were determined, factors influencing the trends were examined. Long-term snowfall trends for CNY were positive for original stations (˜0.46 +/- 0.20 in. yr -1) and homogenously filtered stations (0.23 +/- 0.20 in. yr -1). However, snowfall trends for shorter time-increments within the long-term period were not consistent, as positive, negative, and neutral trends were calculated. Regional differences in snowfall trends were observed for CNY as typical lake-effect areas (northern counties, the Tug Hill Plateau and the Southern Hills) experienced larger snowfall trends than areas less dominated by LES. Typical lake-effect months (December - February) experienced the greatest snowfall trend in CNY compared to other winter months. The

  16. Comparisons of Snowfall Measurements in Complex Terrain Made During the 2010 Winter Olympics in Vancouver

    NASA Astrophysics Data System (ADS)

    Boudala, Faisal S.; Isaac, George A.; Rasmussen, Roy; Cober, Stewart G.; Scott, Bill

    2014-01-01

    Solid precipitation (SP) intensity () using four automatic gauges, Pluvio, PARSIVEL (PArticle, SIze and VELocity), FD12P and POSS, and radar reflectivity factor () using the POSS and PARSIVEL were measured at a naturally sheltered station (VOA) located at high level (1,640 m) on the Whistler Mountain in British Colombia, Canada. The R s and other standard meteorological parameters were collected from March 2009, and from November 2009, to February 2010. The wind speed (ws) measured during this period ranged from 0 to 4.5 ms-1, with a mean value of 0.5 ms-1. The temperature varied from 4 to -17 °C. The SP amount reported by the PARSIVEL was higher than that reported by the Pluvio by more than a factor of 2, while the FD12P and POSS measured relatively smaller amounts, but much closer to that reported by the Pluvio and manual measurements. The dependence of R s from the PARSIVEL on wind speed was examined, but no significant dependence was found. The PARSIVEL's precipitation retrieval algorithm was modified and tested using three different snow density size relationships ( ρ s- D) reported in literature. It was found that after modification of the algorithm, the derived R s amounts using the raw data agreed reasonably well with the Pluvio. Statistical analysis shows that more than 95 % of data measured by POSS appears to correlates well with the reflectivity factors determined using the three ρ s- D relationships. The automated Pluvio accumulation and manually determined daily SP amount (SPm) measured during five winter months were compared. The mean ratio (MR) and the mean difference (MD), and the correlation coefficient ( r) calculated using the data collected using the two methods, were found to be 0.96, 0.4 and 0.6 respectively, indicating respectable agreement between these two methods, with only the Pluvio underestimating the amount by about 4 %.

  17. Contrasting effects of warming and increased snowfall on Arctic tundra plant phenology over the past two decades.

    PubMed

    Bjorkman, Anne D; Elmendorf, Sarah C; Beamish, Alison L; Vellend, Mark; Henry, Gregory H R

    2015-12-01

    Recent changes in climate have led to significant shifts in phenology, with many studies demonstrating advanced phenology in response to warming temperatures. The rate of temperature change is especially high in the Arctic, but this is also where we have relatively little data on phenological changes and the processes driving these changes. In order to understand how Arctic plant species are likely to respond to future changes in climate, we monitored flowering phenology in response to both experimental and ambient warming for four widespread species in two habitat types over 21 years. We additionally used long-term environmental records to disentangle the effects of temperature increase and changes in snowmelt date on phenological patterns. While flowering occurred earlier in response to experimental warming, plants in unmanipulated plots showed no change or a delay in flowering over the 21-year period, despite more than 1 °C of ambient warming during that time. This counterintuitive result was likely due to significantly delayed snowmelt over the study period (0.05-0.2 days/yr) due to increased winter snowfall. The timing of snowmelt was a strong driver of flowering phenology for all species - especially for early-flowering species - while spring temperature was significantly related to flowering time only for later-flowering species. Despite significantly delayed flowering phenology, the timing of seed maturation showed no significant change over time, suggesting that warmer temperatures may promote more rapid seed development. The results of this study highlight the importance of understanding the specific environmental cues that drive species' phenological responses as well as the complex interactions between temperature and precipitation when forecasting phenology over the coming decades. As demonstrated here, the effects of altered snowmelt patterns can counter the effects of warmer temperatures, even to the point of generating phenological responses

  18. Orographic enhancement of snowfall.

    PubMed

    Dore, A J; Choularton, T W; Fowler, D; Crossley, A

    1992-01-01

    Field studies have been conducted at a hill site in Scotland to measure the variation with altitude of wet deposition by snowfall. The results showed that, due to wind drift effects, snowflakes were captured very inefficiently by snow collectors. It was therefore not possible to measure an increase in precipitation with altitude. The average concentrations of principal ions dissolved in the snow water were calculated over a two-month period. The results showed that the concentrations increased by factors of between 1.4 and 1.9 with an altitude rise of 400 m. A model of the orographic enhancement of snowfall by the seeder-feeder effect showed that the orographic enhancements of precipitation and pollutant deposition were significantly greater for snowfall than for rainfall. The wind drift of snow crystals and the evaporation of precipitation in dry valley air were important in determining the patterns of deposition. PMID:15092031

  19. Weather Forecasts on Mars: CO2 Snowfalls Related to the Baroclinic Waves in the Northern Winter Polar Atmosphere

    NASA Astrophysics Data System (ADS)

    Kuroda, T.; Medvedev, A. S.; Kasaba, Y.; Hartogh, P.

    2014-07-01

    Our simulations showed that CO2 snow forms in the northen winter high-latitude atmosphere of Mars in regular patches coinciding with passages of baroclinic planetary waves. This discovery would allow to forecast snow storms for future missions.

  20. Twenty-first century changes in snowfall climate in Northern Europe in ENSEMBLES regional climate models

    NASA Astrophysics Data System (ADS)

    Räisänen, Jouni

    2016-01-01

    Changes in snowfall in northern Europe (55-71°N, 5-35°E) are analysed from 12 regional model simulations of twenty-first century climate under the Special Report on Emissions Scenarios A1B scenario. As an ensemble mean, the models suggest a decrease in the winter total snowfall in nearly all of northern Europe. In the middle of the winter, however, snowfall generally increases in the coldest areas. The borderline between increasing and decreasing snowfall broadly coincides with the -11 °C isotherm in baseline (1980-2010) monthly mean temperature, although with variation between models and grid boxes. High extremes of daily snowfall remain nearly unchanged, except for decreases in the mildest areas, where snowfall as a whole becomes much less common. A smaller fraction of the snow in the simulated late twenty-first century climate falls on severely cold days and a larger fraction on days with near-zero temperatures. Not only do days with low temperatures become less common, but they also typically have more positive anomalies of sea level pressure and less snowfall for the same temperature than in the present-day climate.

  1. ATMS Snowfall Rate Product and Its Applications

    NASA Astrophysics Data System (ADS)

    Meng, H.; Kongoli, C.; Dong, J.; Wang, N. Y.; Ferraro, R. R.; Zavodsky, B.; Banghua Yan, B.

    2015-12-01

    A snowfall rate (SFR) algorithm has been developed for the Advanced Technology Microwave Sounder (ATMS) aboard S-NPP and future JPSS satellites. The product is based on the NOAA/NESDIS operational Microwave Humidity Sounder (MHS) SFR but with several key advancements. The algorithm has benefited from continuous development to improve accuracy and snowfall detection efficiency. The enhancements also expand the applicable temperature range for the algorithm and allow significantly more snowfall to be detected than the operational SFR. Another major improvement is the drastically reduced product latency by using Direct Broadcast (DB) data. The new developments have also been implemented in the MHS SFR to ensure product consistency across satellites. Currently, there are five satellites that carry either ATMS or MHS: S-NPP, NOAA-18/-19 and Metop-A/-B. The combined satellites deliver up to ten SFR estimates a day at any location over land in mid-latitudes. The product provides much needed winter precipitation estimates for applications such as weather forecasting and hydrology. Both ATMS and MHS SFR serve as input to a global precipitation analysis product, the NOAA/NCEP CMORPH-Snow. SFR is the sole satellite-based snowfall estimates in the blended product. In addition, ATMS and MHS SFR was assessed at several NWS Weather Forecast Offices (WFOs) and NESDIS/Satellite Analysis Branch (SAB) for its operational values in winter 2015. This is a joint effort among NASA/SPoRT, NOAA/NESDIS, University of Maryland/CICS, and the WFOs. The feedback from the assessment indicated that SFR provides useful information for snowfall forecast. It is especially valuable for areas with poor radar coverage and ground observations. The feedback also identified some limitations of the product such as inadequate detection of shallow snowfall. The algorithm developers will continue to improve product quality as well as developing SFR for new microwave sensors and over ocean in a project

  2. The annual cycle of snowfall at Summit, Greenland

    NASA Astrophysics Data System (ADS)

    Castellani, Benjamin Brian

    The mass balance of interior Greenland is much less understood than the oft-studied melting coastal regions due to a dearth of observations. The ICECAPS project, which launched in the summer of 2010 at Summit, Greenland, offers a unique, ground-based opportunity to study precipitation in central Greenland where the mass balance is marginally positive. Combing the perspectives from a Precipitation Occurrence Sensor System (POSS), a Millimeter- wavelength Cloud Radar (MMCR), and an accumulation field, the annual cycle of precipitation at Summit is examined. The annual average snowfall measured by the POSS (MMCR) is 83.3 mm (88.8 mm) of liquid equivalent, with the seasonal cycle defined by a large peak in summer and a smaller one in late winter. Accumulation showed a similar seasonal pattern, though with damped variability and a one or two month time lag. Daily snowfall increases by a factor of 3 from June through October compared to the rest of the year, while accumulation only increases 18% during the same timeframe. This reduced variability is explained by the seasonally-varying nature of latent heat flux, compaction, and wind contributions. The ICECAPS remote sensors and the accumulation field measurements do not completely agree as far as total annual liquid equivalent. The deposition of snow by wind, among other factors, is suggested as a possible contributor to the discrepancy. To further examine the seasonal cycle, snowfall measurements by the POSS were linked to other local meteorological parameters, including wind direction, liquid water path (LWP), 2-m temperature, and precipitable water vapor (PWV). Snowfall rarely occurs and is typically very light if the wind does not have a southerly component, except in the summertime, for which moderate snowfall often coincides with all wind directions. Snowfall rate and occurrence are higher when PWV exceeds the current month's mean PWV. The wind direction and moisture dependence are consistent with snowfall being

  3. Snowfall Rate Retrieval Using Passive Microwave Measurements and Its Applications in Weather Forecast and Hydrology

    NASA Technical Reports Server (NTRS)

    Meng, Huan; Ferraro, Ralph; Kongoli, Cezar; Yan, Banghua; Zavodsky, Bradley; Zhao, Limin; Dong, Jun; Wang, Nai-Yu

    2015-01-01

    (AMSU), Microwave Humidity Sounder (MHS) and Advance Technology Microwave Sounder (ATMS). ATMS is the follow-on sensor to AMSU and MHS. Currently, an AMSU and MHS based land snowfall rate (SFR) product is running operationally at NOAA/NESDIS. Based on the AMSU/MHS SFR, an ATMS SFR algorithm has also been developed. The algorithm performs retrieval in three steps: snowfall detection, retrieval of cloud properties, and estimation of snow particle terminal velocity and snowfall rate. The snowfall detection component utilizes principal component analysis and a logistic regression model. It employs a combination of temperature and water vapor sounding channels to detect the scattering signal from falling snow and derives the probability of snowfall. Cloud properties are retrieved using an inversion method with an iteration algorithm and a two-stream radiative transfer model. A method adopted to calculate snow particle terminal velocity. Finally, snowfall rate is computed by numerically solving a complex integral. The SFR products are being used mainly in two communities: hydrology and weather forecast. Global blended precipitation products traditionally do not include snowfall derived from satellites because such products were not available operationally in the past. The ATMS and AMSU/MHS SFR now provide the winter precipitation information for these blended precipitation products. Weather forecasters mainly rely on radar and station observations for snowfall forecast. The SFR products can fill in gaps where no conventional snowfall data are available to forecasters. The products can also be used to confirm radar and gauge snowfall data and increase forecasters' confidence in their prediction.

  4. Trends of Future Heavy Snowfall and Accumulated Freezing Indexes in Japanese Snowy Cold Region

    NASA Astrophysics Data System (ADS)

    Harada, Y.; Matsuzawa, M.

    2015-12-01

    To achieve sufficient, effective winter road maintenance, it is important that long-term snow and ice hazard mitigation plans be examined and formulated by taking into consideration the influence of climate change. In this study, we have developed a method of predicting more accurately the indexes of heavy snowfall events that occur over short periods of time and future projections of winter temperatures based on the relationship of observed data to the climate model predicted values. The indexes for heavy snowfall were the maximum 24-hour snowfall and the frequency of 10-cm or more snowfall within a maximum 6-hour period. Indexes for cold weather were the accumulated freezing index in winter and the number of days of freeze-thaw days. Subsequently, we have applied this methodology for Japanese snowy cold regions, in order to clarify the trends for near future and century-end future period changes. The results indicate that current measures to mitigate the effects of extremely heavy snowfall in inland areas of Hokkaido may require enhancement of operational procedures. In addition, the possibility of pavement and concrete damage in the colder regions is expected to increase due to the increment in the number of freeze-thaw days. Based upon the results of this study, we will identify the road management issues associated with climate change using the recent trends and predictions for the near future and century-end future climate periods.

  5. Contrasting responses of mean and extreme snowfall to climate change.

    PubMed

    O'Gorman, Paul A

    2014-08-28

    Snowfall is an important element of the climate system, and one that is expected to change in a warming climate. Both mean snowfall and the intensity distribution of snowfall are important, with heavy snowfall events having particularly large economic and human impacts. Simulations with climate models indicate that annual mean snowfall declines with warming in most regions but increases in regions with very low surface temperatures. The response of heavy snowfall events to a changing climate, however, is unclear. Here I show that in simulations with climate models under a scenario of high emissions of greenhouse gases, by the late twenty-first century there are smaller fractional changes in the intensities of daily snowfall extremes than in mean snowfall over many Northern Hemisphere land regions. For example, for monthly climatological temperatures just below freezing and surface elevations below 1,000 metres, the 99.99th percentile of daily snowfall decreases by 8% in the multimodel median, compared to a 65% reduction in mean snowfall. Both mean and extreme snowfall must decrease for a sufficiently large warming, but the climatological temperature above which snowfall extremes decrease with warming in the simulations is as high as -9 °C, compared to -14 °C for mean snowfall. These results are supported by a physically based theory that is consistent with the observed rain-snow transition. According to the theory, snowfall extremes occur near an optimal temperature that is insensitive to climate warming, and this results in smaller fractional changes for higher percentiles of daily snowfall. The simulated changes in snowfall that I find would influence surface snow and its hazards; these changes also suggest that it may be difficult to detect a regional climate-change signal in snowfall extremes. PMID:25164753

  6. Sunspots and Snowfall

    ERIC Educational Resources Information Center

    Starr, Richard R.

    1978-01-01

    Examination of the snowfall and total precipitation data for Rochester, New York, suggests a correlation with sunspot activity. Data from other locations tend to support the thesis, but the ability to predict yearly snowfall or total precipitation amounts from sunspot activity has yet to be developed. (Author/CP)

  7. Anchorage Receives Record Snowfall

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The forecast called for flurries, but the snow accumulated on the ground in Anchorage, Alaska, at the rate of 2 inches per hour (5 cm per hour) for much of Saturday, March 16, 2002. By the time the winter storm passed on Sunday afternoon, Anchorage had received 28.6 inches (72.6 cm) of snow, surpassing by far the previous record of 15.6 inches (39.6 cm) set on December 29, 1955. Flights were canceled and schools were closed as a result of the storm. This true-color image of Alaska was acquired by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), flying aboard the OrbView-2 satellite, on March 18. It appears another large, low-pressure system is heading toward the Anchorage region, which could bring substantially more snowfall. The low-pressure system can be identified by the characteristic spiral pattern of clouds located off Alaska's southwestern coast in this scene.

  8. Variations in northern hemisphere snowfall: An analysis of historical trends and the projected response to anthropogenic forcing in the twenty-first century

    NASA Astrophysics Data System (ADS)

    Krasting, John P.

    Snowfall is an important feature of the Earth's climate system that has the ability to influence both the natural world and human activity. This dissertation examines past and future changes in snowfall related to increasing concentrations of anthropogenic greenhouse gases. Snowfall observations for North America, derived snowfall products for the Northern Hemisphere, and simulations performed with 13 coupled atmosphere-ocean global climate models are analyzed. The analysis of the spatial pattern of simulated annual trends on a grid point basis from 1951 to 1999 indicates that a transition zone exists above 60° N latitude across the Northern Hemisphere that separates negative trends in annual snowfall in the mid-latitudes and positive trends at higher latitudes. Regional analysis of observed annual snowfall indicates that statistically significant trends are found in western North America, Japan, and southern Russia. A majority of the observed historical trends in annual snowfall elsewhere in the Northern Hemisphere, however, are not statistically significant and this result is consistent with model simulations. Projections of future snowfall indicate the presence of a similar transition zone between negative and positive snowfall trends that corresponds with the area between the -10 to -15°C isotherms of the multi-model mean temperature of the late twentieth century in each of the fall, winter, and spring seasons. Redistributions of snowfall throughout the entire snow season are likely -- even in locations where there is little change in annual snowfall. Changes in the fraction of precipitation falling as snow contribute to decreases in snowfall across most Northern Hemisphere regions, while changes in precipitation typically contribute to increases in snowfall. Snowfall events less than or equal to 5 cm are found to decrease in the future across most of the Northern Hemisphere, while snowfall events greater than or equal to 20 cm increase in some locations

  9. Incidence of plague associated with increased winter-spring precipitation in New Mexico.

    PubMed

    Parmenter, R R; Yadav, E P; Parmenter, C A; Ettestad, P; Gage, K L

    1999-11-01

    Plague occurs episodically in many parts of the world, and some outbreaks appear to be related to increased abundance of rodents and other mammals that serve as hosts for vector fleas. Climate dynamics may influence the abundance of both fleas and mammals, thereby having an indirect effect on human plague incidence. An understanding of the relationship between climate and plague could be useful in predicting periods of increased risk of plague transmission. In this study, we used correlation analyses of 215 human cases of plague in relation to precipitation records from 1948 to 1996 in areas of New Mexico with history of human plague cases (38 cities, towns, and villages). We conducted analyses using 3 spatial scales: global (El Niño-Southern Oscillation Indices [SOI]); regional (pooled state-wide precipitation averages); and local (precipitation data from weather stations near plague case sites). We found that human plague cases in New Mexico occurred more frequently following winter-spring periods (October to May) with above-average precipitation (mean plague years = 113% of normal rain/ snowfall), resulting in 60% more cases of plague in humans following wet versus dry winter-spring periods. However, we obtained significant results at local level only; regional state-wide precipitation averages and SOI values exhibited no significant correlations to incidence of human plague cases. These results are consistent with our hypothesis of a trophic cascade in which increased winter-spring precipitation enhances small mammal food resource productivity (plants and insects), leading to an increase in the abundance of plague hosts. In addition, moister climate conditions may act to promote flea survival and reproduction, also enhancing plague transmission. Finally, the result that the number of human plague cases in New Mexico was positively associated with higher than normal winter-spring precipitation at a local scale can be used by physicians and public health

  10. Snowfall Retrivals Using a Video Disdrometer

    NASA Astrophysics Data System (ADS)

    Newman, A. J.; Kucera, P. A.

    2004-12-01

    A video disdrometer has been recently developed at NASA/Wallops Flight Facility in an effort to improve surface precipitation measurements. One of the goals of the upcoming Global Precipitation Measurement (GPM) mission is to provide improved satellite-based measurements of snowfall in mid-latitudes. Also, with the planned dual-polarization upgrade of US National Weather Service weather radars, there is potential for significant improvements in radar-based estimates of snowfall. The video disdrometer, referred to as the Rain Imaging System (RIS), was deployed in Eastern North Dakota during the 2003-2004 winter season to measure size distributions, precipitation rate, and density estimates of snowfall. The RIS uses CCD grayscale video camera with a zoom lens to observe hydrometers in a sample volume located 2 meters from end of the lens and approximately 1.5 meters away from an independent light source. The design of the RIS may eliminate sampling errors from wind flow around the instrument. The RIS operated almost continuously in the adverse conditions often observed in the Northern Plains. Preliminary analysis of an extended winter snowstorm has shown encouraging results. The RIS was able to provide crystal habit information, variability of particle size distributions for the lifecycle of the storm, snowfall rates, and estimates of snow density. Comparisons with coincident snow core samples and measurements from the nearby NWS Forecast Office indicate the RIS provides reasonable snowfall measurements. WSR-88D radar observations over the RIS were used to generate a snowfall-reflectivity relationship from the storm. These results along with several other cases will be shown during the presentation.

  11. Sensitivity studies of the effect of increased aerosol concentrations and snow crystal shape on the snowfall rate in the Arctic

    NASA Astrophysics Data System (ADS)

    Lohmann, U.; Zhang, J.; Pi, J.

    2003-06-01

    The mesoscale model GESIMA is used to simulate microphysical properties of Arctic clouds and their effect on radiation. Different case studies during the FIRE ACE/SHEBA project show that GESIMA is able to simulate the cloud boundaries, ice and liquid water content, and effective radii in good agreement with observations. For two different aerosol scenarios, the simulation results show that the anthropogenic aerosol can alter microphysical properties of Arctic clouds, and consequently modify surface precipitation. [2000] proposed that anthropogenically induced decreases in cloud droplet size inhibit the riming process. On the contrary, we find that the accretion of snow crystals with cloud droplets is increased in the polluted cloud owing to its higher cloud droplet number concentration. Instead, the autoconversion rate of cloud droplets and accretion of drizzle by snow decreases caused by the shutdown of the collision-coalescence process in the polluted cloud. The amount of precipitation reaching the surface as snow depends crucially on the crystal shape. If aggregates are assumed, then a tenfold increase in aerosol concentration leads to an increase in accumulated snow by 40% after 7 hours of simulation whereas the snow amount decreases by 30% when planar crystals are assumed because of the larger accretion efficiency of snow crystals with cloud droplets in case of aggregates.

  12. Unusually cold and dry winters increase mortality in Australia.

    PubMed

    Huang, Cunrui; Chu, Cordia; Wang, Xiaoming; Barnett, Adrian G

    2015-01-01

    Seasonal patterns in mortality have been recognised for decades, with a marked excess of deaths in winter, yet our understanding of the causes of this phenomenon is not yet complete. Research has shown that low and high temperatures are associated with increased mortality independently of season; however, the impact of unseasonal weather on mortality has been less studied. In this study, we aimed to determine if unseasonal patterns in weather were associated with unseasonal patterns in mortality. We obtained daily temperature, humidity and mortality data from 1988 to 2009 for five major Australian cities with a range of climates. We split the seasonal patterns in temperature, humidity and mortality into their stationary and non-stationary parts. A stationary seasonal pattern is consistent from year-to-year, and a non-stationary pattern varies from year-to-year. We used Poisson regression to investigate associations between unseasonal weather and an unusual number of deaths. We found that deaths rates in Australia were 20-30% higher in winter than summer. The seasonal pattern of mortality was non-stationary, with much larger peaks in some winters. Winters that were colder or drier than a typical winter had significantly increased death risks in most cities. Conversely summers that were warmer or more humid than average showed no increase in death risks. Better understanding the occurrence and cause of seasonal variations in mortality will help with disease prevention and save lives. PMID:25460613

  13. Natural Variability during Snowfall: Observations of Snowflake Microstructure and Calculations of Corresponding Snowfall Scattering Properties

    NASA Astrophysics Data System (ADS)

    Gergely, M.; Garrett, T. J.

    2015-12-01

    Significant progress has been achieved in approximating snowflakes and ice-cloud particles by increasingly more realistic and detailed shape models and in calculating associated scattering properties crucial to snowfall remote sensing. The applied approximations of the snowflake microstructure applied for the scattering calculations, however, are still based on few available field measurement data, often integrated over many individual snow storms, and only include several microstructural properties that cannot fully capture the natural variability during snowfall, e.g. different degrees of riming or aggregate snowflakes formed from more than one distinct ice crystal habit. In this study, (i) the natural variability of key microstructural properties during snowfall is quantified for individual snow storms based on high-resolution multi-view snowflake imaging data collected with the Multi-Angle Snowflake Camera (MASC) at Alta ski area (Alta, UT), and (ii) the corresponding variability in snowflake scattering properties is calculated. In addition to snowflake size, orientation and aspect ratio, 'particle complexity' (specifying snowflake perimeter and brightness variations in the MASC snowflake images) is included in the presented approach, yielding a quantitative and objective measure of characteristic snowflake microstructure, including crystal habit and degree of riming, important for realistically modelling snowfall scattering properties. The aim is to present an analysis of the impact of the observed natural microstructural variability on the derived snowflake scattering properties and ultimately on the snowfall radar reflectivity integrated over the obtained variability of snowflake microstructure and scattering properties.

  14. NPP ATMS Snowfall Rate Product

    NASA Technical Reports Server (NTRS)

    Meng, Huan; Ferraro, Ralph; Kongoli, Cezar; Wang, Nai-Yu; Dong, Jun; Zavodsky, Bradley; Yan, Banghua

    2015-01-01

    Passive microwave measurements at certain high frequencies are sensitive to the scattering effect of snow particles and can be utilized to retrieve snowfall properties. Some of the microwave sensors with snowfall sensitive channels are Advanced Microwave Sounding Unit (AMSU), Microwave Humidity Sounder (MHS) and Advance Technology Microwave Sounder (ATMS). ATMS is the follow-on sensor to AMSU and MHS. Currently, an AMSU and MHS based land snowfall rate (SFR) product is running operationally at NOAA/NESDIS. Based on the AMSU/MHS SFR, an ATMS SFR algorithm has been developed recently. The algorithm performs retrieval in three steps: snowfall detection, retrieval of cloud properties, and estimation of snow particle terminal velocity and snowfall rate. The snowfall detection component utilizes principal component analysis and a logistic regression model. The model employs a combination of temperature and water vapor sounding channels to detect the scattering signal from falling snow and derive the probability of snowfall (Kongoli et al., 2015). In addition, a set of NWP model based filters is also employed to improve the accuracy of snowfall detection. Cloud properties are retrieved using an inversion method with an iteration algorithm and a two-stream radiative transfer model (Yan et al., 2008). A method developed by Heymsfield and Westbrook (2010) is adopted to calculate snow particle terminal velocity. Finally, snowfall rate is computed by numerically solving a complex integral. NCEP CMORPH analysis has shown that integration of ATMS SFR has improved the performance of CMORPH-Snow. The ATMS SFR product is also being assessed at several NWS Weather Forecast Offices for its usefulness in weather forecast.

  15. Decreased winter severity increases viability of a montane frog population.

    PubMed

    McCaffery, Rebecca M; Maxell, Bryce A

    2010-05-11

    Many proximate causes of global amphibian declines have been well documented, but the role that climate change has played and will play in this crisis remains ambiguous for many species. Breeding phenology and disease outbreaks have been associated with warming temperatures, but, to date, few studies have evaluated effects of climate change on individual vital rates and subsequent population dynamics of amphibians. We evaluated relationships among local climate variables, annual survival and fecundity, and population growth rates from a 9-year demographic study of Columbia spotted frogs (Rana luteiventris) in the Bitterroot Mountains of Montana. We documented an increase in survival and breeding probability as severity of winter decreased. Therefore, a warming climate with less severe winters is likely to promote population viability in this montane frog population. More generally, amphibians and other ectotherms inhabiting alpine or boreal habitats at or near their thermal ecological limits may benefit from the milder winters provided by a warming climate as long as suitable habitats remain intact. A more thorough understanding of how climate change is expected to benefit or harm amphibian populations at different latitudes and elevations is essential for determining the best strategies to conserve viable populations and allow for gene flow and shifts in geographic range. PMID:20421473

  16. Decreased winter severity increases viability of a montane frog population

    PubMed Central

    McCaffery, Rebecca M.; Maxell, Bryce A.

    2010-01-01

    Many proximate causes of global amphibian declines have been well documented, but the role that climate change has played and will play in this crisis remains ambiguous for many species. Breeding phenology and disease outbreaks have been associated with warming temperatures, but, to date, few studies have evaluated effects of climate change on individual vital rates and subsequent population dynamics of amphibians. We evaluated relationships among local climate variables, annual survival and fecundity, and population growth rates from a 9-year demographic study of Columbia spotted frogs (Rana luteiventris) in the Bitterroot Mountains of Montana. We documented an increase in survival and breeding probability as severity of winter decreased. Therefore, a warming climate with less severe winters is likely to promote population viability in this montane frog population. More generally, amphibians and other ectotherms inhabiting alpine or boreal habitats at or near their thermal ecological limits may benefit from the milder winters provided by a warming climate as long as suitable habitats remain intact. A more thorough understanding of how climate change is expected to benefit or harm amphibian populations at different latitudes and elevations is essential for determining the best strategies to conserve viable populations and allow for gene flow and shifts in geographic range. PMID:20421473

  17. Future snowfall in western and central Europe projected with a high-resolution regional climate model ensemble

    NASA Astrophysics Data System (ADS)

    Vries, Hylke; Lenderink, Geert; Meijgaard, Erik

    2014-06-01

    Snowfall frequency and intensity are influenced strongly by climate change. Here we separate the basic frequency change resulting from a gradually warming climate, from the intensity changes, by focusing on snowfall on days where the mean temperature is below freezing (Hellmann days). Using an ensemble of simulations, obtained with the high-resolution regional climate model KNMI-RACMO2 driven by the EC-EARTH global climate model and RCP4.5 and RCP8.5 forcing scenarios, we show that in addition to the strong decrease in the number of Hellmann days, also a substantial reduction in the mean Hellmann-day snowfall can be expected over large parts of western and central Europe. Moreover, seasonal snowfall extremes display trends that are comparable or even larger. Projected intensity reductions are locally as large as -30% per degree warming, thus being in sharp contrast to mean winter precipitation, which increases in most future climate scenarios. Exceptions are the high Alps and parts of Scandinavia, which may see an increase of up to +10% per degree warming.

  18. A snowfall detection algorithm over land utilizing high-frequency passive microwave measurements—Application to ATMS

    NASA Astrophysics Data System (ADS)

    Kongoli, Cezar; Meng, Huan; Dong, Jun; Ferraro, Ralph

    2015-03-01

    This paper presents a snowfall detection algorithm over land from high-frequency passive microwave measurements. The algorithm computes the probability of snowfall using logistic regression and the principal components of the seven high-frequency brightness temperature measurements at Atmospheric Technology Microwave Sounder (ATMS) channel frequencies 89 GHz and above. The oxygen absorption channel 6 (53.6 GHz) is utilized as temperature proxy to define the snowfall retrieval domain. Ground truth surface meteorological data including snowfall occurrence were collected over Conterminous U.S. and Alaska during two winter seasons in 2012-2013 and 2013-2014. Statistical analysis of the in situ data matched with ATMS measurements showed that in relatively warmer weather, snowfall tends to be associated with lower high-frequency brightness temperatures than no snowfall, and the brightness temperatures are negatively correlated with measured snowfall rate. In colder weather conditions, however, snowfall tends to occur at higher microwave brightness temperatures than no-snowfall, and the brightness temperatures are positively correlated with snowfall rate. The brightness temperature decrease and the negative correlations with snowfall rate in warmer weather are attributed to the scattering effect. It is hypothesized that the scattering effect is insignificant in colder weather due to the predominance of lighter snowfall and emission. Based on these results, a two-step algorithm is developed that optimizes snowfall detection over these two distinct temperature regimes. Evaluation of the algorithm shows skill in capturing snowfall in variable weather conditions as well as the remaining challenges in the retrieval of lighter and colder snowfall.

  19. Perennial Forage Kochia for Increased Production of Winter Grazed Pastures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grazing forage kochia (Kochia prostrata) during fall/winter has improved livestock health and reduced winter feeding costs. The objectives of this study were to compare forage production/quality and livestock performance of traditional winter pastures versus pastures with forage kochia. Two kochia...

  20. Artificial lighting during winter increases milk yield in dairy ewes.

    PubMed

    Morrissey, A D; Cameron, A W N; Tilbrook, A J

    2008-11-01

    In Australia, the supply of sheep milk is reduced during the winter. Housing dairy animals under lights during winter is a simple technique to increase milk yield; however, it is difficult to predict the magnitude of this increase in dairy ewes, because there are few corroborating data. We studied 220 East Friesian crossbred ewes (50 primiparous and 170 multiparous ewes, respectively) that lambed in April to May 2007 (late autumn, southern hemisphere) and were weaned from their lambs within 24 h of parturition and milked exclusively by machine. These ewes were ranked according to their milk production, and ewes producing > or =1,000 mL/d of milk were allocated to 1 of 2 groups. One group of ewes was kept indoors under a long-day photoperiod (16 h of light), whereas the other group was kept indoors under a naturally declining day length. Ewes were maintained under these conditions for 8 wk. Milk yield was measured twice weekly, and ewe weight and condition were measured at weekly intervals. From a subset of ewes (n = 20 per group), milk samples were collected twice weekly at the morning milking to measure milk lipid, protein, and lactose, and blood samples were collected once a week to measure plasma prolactin concentrations. Mean daily milk yield was analyzed as a percentage of preexperimental milk yield because the milk yield of ewes housed under the long photoperiod was lower than that of ewes under a declining day length when the treatments began. Thus, the ewes under a long photoperiod yielded 91.7% of their starting yield by wk 8 of treatment, whereas ewes under a declining day length yielded 76.25% of their initial value (LSD = 5.1), and this divergence in milk yield was apparent by wk 2 of treatment. Mean plasma prolactin levels were greater in ewes housed under the long-day photoperiod (n = 20) compared with control ewes (n = 20) at wk 6 (168 +/- 27 vs. 72 +/- 19 ng/mL, respectively), wk 7 (125 +/- 28 vs. 37 +/- 7 ng/mL, respectively), and wk 8 of the

  1. An evaluation of the Wyoming gauge system for snowfall measurement

    USGS Publications Warehouse

    Yang, D.; Kane, D.L.; Hinzman, L.D.; Goodison, B.E.; Metcalfe, J.R.; Louie, P.Y.T.; Leavesley, G.H.; Emerson, D.G.; Hanson, C.L.

    2000-01-01

    The Wyoming snow fence (shield) has been widely used with precipitation gauges for snowfall measurement at more than 25 locations in Alaska since the late 1970s. This gauge's measurements have been taken as the reference for correcting wind-induced gauge undercatch of snowfall in Alaska. Recently, this fence (shield) was tested in the World Meteorological Organization Solid Precipitation Measurement Intercomparison Project at four locations in the United States of America and Canada for six winter seasons. At the Intercomparison sites an octagonal vertical Double Fence with a Russian Tretyakov gauge or a Universal Belfort recording gauge was installed and used as the Intercomparison Reference (DFIR) to provide true snowfall amounts for this intercomparison experiment. The intercomparison data collected were compiled at the four sites that represent a variety of climate, terrain, and exposure. On the basis of these data sets the performance of the Wyoming gauge system for snowfall observations was carefully evaluated against the DFIR and snow cover data. The results show that (1) the mean snow catch efficiency of the Wyoming gauge compared with the DFIR is about 80-90%, (2) there exists a close linear relation between the measurements of the two gauge systems and this relation may serve as a transfer function to adjust the Wyoming gauge records to obtain an estimate of the true snowfall amount, (3) catch efficiency of the Wyoming gauge does not change with wind speed and temperature, and (4) Wyoming gauge measurements are generally compatible to the snowpack water equivalent at selected locations in northern Alaska. These results are important to our effort of determining true snowfall amounts in the high latitudes, and they are also useful for regional hydrologic and climatic analyses.

  2. Analysing long-term changes of extreme snow depth and snowfall with a time-dependent GEV model

    NASA Astrophysics Data System (ADS)

    Marty, C.; Blanchet, J.; Grob, S.

    2010-09-01

    The mountain snow cover is an important source of water and a requirement for winter tourism in Alpine countries. However, large amounts of snow can lead to destructive avalanches, floods, traffic interruption or sometimes even collapse of buildings. We use snow depth and snowfall data of 20 stations (between 200 and 1800 m asl) collected during the last 80 winters (1930/31 to 2009/2010) to highlight temporal trends of annual maximum snow depth and extreme snowfall events. The generalized extreme value (GEV) distribution with time as a covariate is used to study the changes in magnitude and frequency of such events. We analyse how current and future return periods are affected by these changes. We also investigate the spatial spreading and altitudinal dependence of these trends. Our analysis demonstrates that the temporal trends of extreme snow depth and snowfall events do not show the typical climate change signal as for example the mean snow depth. Less than half of all stations show a decreasing trend with time and not even the highest stations show an increase. This implies that for more than half of the stations the return periods of extreme snow events did not change in the last 80 years despite the observed warming.

  3. Deeper winter snow reduces ecosystem C losses but increases the global warming potential of Arctic tussock tundra over the growing season.

    NASA Astrophysics Data System (ADS)

    Blanc-Betes, E.; Welker, J. M.; Gomez-Casanovas, N.; Gonzalez-Meler, M. A.

    2015-12-01

    Arctic winter precipitation is projected to increase globally over the next decades, spatial variability encompassing areas with increases and decreases in winter snow. Changes in winter precipitation strongly affect C dynamics in Arctic systems and may lead to major positive climate forcing feedbacks. However, impacts of predicted changes in snowfall and accumulation on the rate and form of C fluxes (CO2 and CH4) and associated forcing feedbacks from Arctic tundra remain uncertain. We investigated how changes in winter precipitation affect net ecosystem CO2 and CH4 fluxes and budgets of moist acidic tundra in an 18-yrs snow fence experiment over a complete growing season at Toolik Lake, AK. Arctic tundra under ambient winter precipitation (CTL) was a net source of CO2 and CH4, yielding net C losses over the growing season. Reduced snow (-15-30% snow depth; RS) switched the system to a net CO2 sink mostly by limiting SOC decomposition within colder soils. Snow additions progressively reduced net ecosystem CO2 losses compared to CTL, switching the system into a weaker net CO2 source with medium additions (+20-45% snow depth; MS) and into a small net CO2 sink with high additions (+70-100% snow depth; HS). Increasingly wetter soils with snow additions constrained the temperature sensitivity of aerobic decomposition and favored the anaerobic metabolism, buffering ecosystem CO2 losses despite substantial soil warming. Accordingly, Arctic tundra switched from a sustained CH4 sink at RS site to an increasingly stronger CH4 source with snow additions. Accounting for both CO2 and CH4, the RS site became a net C sink over the growing season, overall reducing the global warming potential (CO2 equiv.; GWP) of the system relative to CTL. Snow additions progressively reduced net C losses at the MS site compared to CTL and the system transitioned into a net C sink at HS plots, partly due to the slower metabolism of anaerobic decomposition. However, given the greater radiative

  4. Spatiotemporal Trends in Lake Effect and Continental Snowfall in the Laurentian Great Lakes, 1951-1980.

    NASA Astrophysics Data System (ADS)

    Norton, D. C.; Bolsenga, S. J.

    1993-10-01

    A new raster-based monthly snowfall climatology was derived from 1951-1980 snowfall station data for the Laurentian Great Lakes. An automated methodology was used to obtain higher spatial resolution than previously obtained. The increase in resolution was attained by using all available monthly snowfall data from over 1230 stations per year combined with a monthly lime step to produce high-resolution grids. These monthly grids were combined to produce snow-year grids. Multiyear average grids were created and compared. This technique minimizes traditional problems associated with missing data and variable length station records.The three 10-year average distribution maps presented here indicate a period of increasing snowfall. Windowing of the 30 seasonal grids revealed that increasing snowfall was attributable to an increase in lake effect snowfall and not to continental snowfall. The Great Lakes drainage basin was evaluated for trends within and between monthly and seasonal average snowfall through windowing of all 240 monthly grids. The graphical and statistical evaluation of these trends indicates a strong natural variation in the region's snowfall and reveals an increasing trend during the study period.

  5. Improving Radar Snowfall Measurements Using a Video Disdrometer

    NASA Astrophysics Data System (ADS)

    Newman, A. J.; Kucera, P. A.

    2005-05-01

    A video disdrometer has been recently developed at NASA/Wallops Flight Facility in an effort to improve surface precipitation measurements. The recent upgrade of the UND C-band weather radar to dual-polarimetric capabilities along with the development of the UND Glacial Ridge intensive atmospheric observation site has presented a valuable opportunity to attempt to improve radar estimates of snowfall. The video disdrometer, referred to as the Rain Imaging System (RIS), has been deployed at the Glacial Ridge site for most of the 2004-2005 winter season to measure size distributions, precipitation rate, and density estimates of snowfall. The RIS uses CCD grayscale video camera with a zoom lens to observe hydrometers in a sample volume located 2 meters from end of the lens and approximately 1.5 meters away from an independent light source. The design of the RIS may eliminate sampling errors from wind flow around the instrument. The RIS has proven its ability to operate continuously in the adverse conditions often observed in the Northern Plains. The RIS is able to provide crystal habit information, variability of particle size distributions for the lifecycle of the storm, snowfall rates, and estimates of snow density. This information, in conjunction with hand measurements of density and crystal habit, will be used to build a database for comparisons with polarimetric data from the UND radar. This database will serve as the basis for improving snowfall estimates using polarimetric radar observations. Preliminary results from several case studies will be presented.

  6. The North Atlantic Oscillation: Impact on Snowfall Conditions in the Northeastern U.S

    NASA Astrophysics Data System (ADS)

    Budikova, D.; Widen, H.; Coleman, J. S.

    2013-12-01

    The North Atlantic Oscillation (NAO) is one of the main components of atmospheric circulation variability within the middle and high latitudes of the Northern Hemisphere, particularly impacting winter weather patterns in northeastern United States. Previous research has indicated greater snowfall totals and higher frequency of snowfall days in the Northeast during a NAO negative phase due to repeated polar outbreaks; yet, the NAO positive phase has also been associated with extreme snowfall events in this region. This study examines the relationship between the NAO and winter (December - February) snowfall totals in northeastern U.S. between 1961 and 2010. Two case studies of recent winter events with differing NAO phases were evaluated to provide insight on how both NAO phases can produce significant snowfall in portions of the Northeast. The analysis revealed an inverse relationship between the NAO phase and seasonal snowfall, with positive (negative) NAO index years associated with lower (higher) average snowfall and snowfall days. Significantly greater snowfall during the NAO negative phase was mainly located along the East Coast as well as the interior southern half of the study region. A composite analysis of various tropospheric variables (e.g., 500-hPa heights) showed NAO negative years produced greater snowfall due to more extreme weather conditions affecting the Northeast, such as below normal sea level pressure, a deepened mid-tropospheric trough and weaker upper-level westerlies that permitted more frequent polar outbreaks. The intrusion of cold polar air into the interior U.S. generates more extreme temperature gradients and produces snowfall farther south than the NAO positive phase. In addition, the eastward displacement of the storms in the NAO negative phase along with the available moisture from the Atlantic Ocean creates more snowfall along the East Coast. These results correspond to the spatial distribution of snowfall that occurred during the

  7. Climatological characterization of wind and snowfall in Minnesota and assessing the impacts of living snow fences

    NASA Astrophysics Data System (ADS)

    Shulski, Martha Elizabeth Durr

    Blowing and drifting snow on roadways is a common occurrence in Minnesota due to the topographic, vegetative, and winter climate characteristics of this area. Through proper road design and the use of snow fences this problem can be alleviated, however snowfall and wind climatological information must first be analyzed. Archived climatological records for locations in Minnesota were recently compiled. Snowfall time series data show a statistically significant increase of 28cm in the annual total since 1890. The increase is shown to occur for November--December while February and March show a decrease. This increase is largely due to an increase in the frequency of snow events less than 10cm. Wind data from federal observing sites in Minnesota show a correlation to landscape variability, with a high frequency of higher wind speeds in western and southern Minnesota. A snow relocation factor needed to quantify seasonal snow transport was calculated and shows a strong dependence on the wind speed distribution. A case study of the 2000--01 winter season allowed for examination of snow storage and agricultural implications of three living snow fence designs in southern Minnesota (two 8-row strips of corn, twin-row honeysuckle, single-row honeysuckle/red cedar). For a winter with high seasonal snowfall and spring rainfall, results of snow storage and modeled seasonal snow transport show good agreement for the two corn row strips. However, snow storage totaled approximately 50% of the modeled snow transport for the honeysuckle fence designs, which appeared to reach storage capacity prior to the end of the snow season. A key factor is the absence of a bottom gap, which promotes leeward displacement of the downwind drift and prevents snow deposition on the fence. Soil temperature and frost depth data show a moderation in temperatures and a decrease in freezing depth with an increase in associated snowpack depth. Post-season soil moisture shows no significant variability with

  8. Compatibility of Canadian Snowfall and Snow Cover Data

    NASA Astrophysics Data System (ADS)

    Goodison, B. E.

    1981-08-01

    The accuracy and compatibility of Canadian snowfall and snow survey data were investigated in the Cold Creek research basin in southern Ontario. Problems in obtaining compatible point measurements of snowfall precipitation from gauge and ruler measurements are discussed. However, it is shown that correction of gauge measurements (MSC Nipher, Universal, Fischer and Porter) of snowfall water equivalent for catch variations caused by environmental factors, notably wind speed, results in compatible storm or seasonal totals. Accurate statistics of basin snow cover were determined from snow courses specifically sited in relation to basin land use. At the time of peak accumulation, which might occur at any time during the winter, there was a statistically significant difference in snow cover between land use categories. Mean basin snow cover was calculated by weighting the snow survey measurements in proportion to basin land use. The need to consider the effect of changing land use on snow course measurements is demonstrated. Results show that as an alternative to direct snow survey measurements, accumulated precipitation may be used to estimate snow cover up to peak accumulation. Net snow cover determined from accumulated corrected gauge data less short-term melt losses and snow evaporation was within the confidence limits of the basin mean snow cover measured during the winter. Compatible results are only achieved when precipitation measurements are corrected for gauge catch variations and snow survey data are representative of basin land use.

  9. Temperature and snowfall trigger alpine vegetation green-up on the world's roof.

    PubMed

    Chen, Xiaoqiu; An, Shuai; Inouye, David W; Schwartz, Mark D

    2015-10-01

    Rapid temperature increase and its impacts on alpine ecosystems in the Qinghai-Tibetan Plateau, the world's highest and largest plateau, are a matter of global concern. Satellite observations have revealed distinctly different trend changes and contradicting temperature responses of vegetation green-up dates, leading to broad debate about the Plateau's spring phenology and its climatic attribution. Large uncertainties in remote-sensing estimates of phenology significantly limit efforts to predict the impacts of climate change on vegetation growth and carbon balance in the Qinghai-Tibetan Plateau, which are further exacerbated by a lack of detailed ground observation calibration. Here, we revealed the spatiotemporal variations and climate drivers of ground-based herbaceous plant green-up dates using 72 green-up datasets for 22 herbaceous plant species at 23 phenological stations, and corresponding daily mean air temperature and daily precipitation data from 19 climate stations across eastern and southern parts of the Qinghai-Tibetan Plateau from 1981 to 2011. Results show that neither the continuously advancing trend from 1982 to 2011, nor a turning point in the mid to late 1990s as reported by remote-sensing studies can be verified by most of the green-up time series, and no robust evidence for a warmer winter-induced later green-up dates can be detected. Thus, chilling requirements may not be an important driver influencing green-up responses to spring warming. Moreover, temperature-only control of green-up dates appears mainly at stations with relatively scarce preseason snowfall and lower elevation, while coupled temperature and precipitation controls of green-up dates occur mostly at stations with relatively abundant preseason snowfall and higher elevation. The diversified interactions between snowfall and temperature during late winter to early spring likely determine the spatiotemporal variations of green-up dates. Therefore, prediction of vegetation growth

  10. Synoptic climatological study on the decrease in heavy snowfall days in Hokuriku District of Central Japan after the latter half of 1980s

    NASA Astrophysics Data System (ADS)

    Kato, Kuranoshin; Kan, Yuusuke

    2010-05-01

    Many reports point out that the total snowfall amount in winter in the Japan Sea side of the Japan Islands, such as Hokuriku District, decreased considerably after the latter half of 1980s, in coincidence with the Global Warming together with the interdecadal variation. As for around December, this seems to be partly because more precipitation in the winter monsoon situation is brought as rainfall (not as snowfall), due to the warmer temperature than before. On the other hand, contribution of the daily heavy snowfall events there would be also important for mid-winter when the air temperature is the lowest in a year. Thus the present study examined the contribution of the heavy snowfall events to the difference of the total snowfall amount before and after the middle of 1980s, based on the daily data at several operational surface observation stations of JMA in the Hokuriku District for 1971 - 2001. Then the related daily atmospheric fields were analyzed climatologically with use of the NCEP/NCAR re-analysis data with every 2.5 degrees latitude/longitude interval. In the former half of the analysis period, the larger total snowfall amount in January in the Hokuriku District, such as at Takada, was greatly contributed to by the heavy snowfall events with more than 30 cm/day (referred to as "heavy snowfall day", hereafter). The decrease in the total amount in the latter half of that period was due to that in the contribution of "heavy snowfall days". Furthermore, the "heavy snowfall days" tended to appear in the persistent snowfall episodes (including also the days with 10 cm/day), before around 1986. In short, the decrease in the total snowfall in the latter half period there seems to be reflected by the weakening of persistency of heavy snowfall episodes. As shown by Akiyama (1981a and b) in detail, there are several different synoptic situations in the winter monsoon situation for bringing heavy snowfall there (the "mountain snow type" and the "plateau snow type

  11. MANAGEMENT TOOLS TO INCREASE THE EFFICIENCY OF WINTER WHEAT-STOCKER ENTERPRISES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over 23 million acres of winter wheat are planted in the southern Great Plains each year, and serves as the major feed resource used by regional stocker cattle enterprises. To increase the efficiency and productivity of winter wheat stocker enterprises, two constraints must be removed. First, length...

  12. Summer Snowfall Impact on Greenland Ice Sheet SMB

    NASA Astrophysics Data System (ADS)

    Noel, B.; Van De Berg, W. J.; van Meijgaard, E.; van den Broeke, M. R.

    2014-12-01

    Recently, the regional climate model RACMO2 has been updated to the version 2.3. The main physics update consists of an enhanced rainfall to snowfall conversion rate, favouring solid over liquid precipitation at higher temperatures, especially in summer. In the updated RACMO2.3 simulation, SMB anomalies are generated through a feedback mechanism involving increased summer snowfall, surface albedo rise as well as cloud cover reduction, resulting in a subsequent decrease of snowmelt and runoff. When compared against K-transect measurements in western Greenland, these updates improve the modelled surface energy balance and surface mass balance relative to the previous RACMO2 version. In addition, the heavier summer snowfall improves the simulated surface albedo in comparison with stations measurements. In recent years, the surface albedo close to the equilibrium line declined notably in summer due to a prolonged bare ice exposure and a decreasing ice albedo. RACMO2.3 results reveal that this rapid reduction in bare ice albedo is not exclusively driven by surface processes related to melt. A major summer snowfall reduction also plays a role in extending the period of bare ice exposure, in turn lowering surface albedo.

  13. Climate Change Impact on Snowfall, Evapotransportation and Streamflow in a Temperate, Wet Watershed

    NASA Astrophysics Data System (ADS)

    al Aamery, N. M. H.; Fox, J.; Snyder, M. A.

    2015-12-01

    Climate change is expected to significantly impact hydrological processes and streamflow at a regional scale, and the motivation of this research is to gain a better understanding of these processes in temperate, wet regions. While numerous studies have recently focused on projected reductions in snowfall and the impact on streamflow in dry and mountainous regions, much less research has investigated hydrologic processes and streamflow in temperate, wet regions which are expected to receive increases in precipitation during the winter season. We use dynamically and statistically downscaled climate projections and perform hydrological simulations using the Soil Water Assessment Tool (SWAT) for central Kentucky, USA. The study region is chosen because it is located in a region that receives a mixture of rain, snow and ice in wintertime, and thus the region is expected to be particularly sensitive to future changes in precipitation and temperature. The SWAT model was first evaluated in a hindcast analyses for the South Elkhorn Watershed and then driven for future conditions by using downscaled temperature and precipitation data from three different projects including the North American Regional Climate Change Assessment Program, Coupled Model Intercomparison Project Phase 5, and Coupled Model Intercomparison Project Phase 3. The average ensemble climate change results indicates an increase in the average annual of daily temperature by 2.6oC for the period 2046 to 2065 as compared to the period 1981 to 2000, and predicts an increase in the annual precipitation by 8%, with the majority of the increase coming in winter (14% in winter and 2% in summer). SWAT suggests a significant stream flow impact due to climate change including an increase in the average annual stream flow by as much as 26%; attributed to the fact that the climate projections predict more precipitation in winter which increases the snowfall and changes the surface albedo. Hence, the evapotranspiration

  14. Polarization Lidar Liquid Cloud Detection Algorithm for Winter Mountain Storms

    NASA Technical Reports Server (NTRS)

    Sassen, Kenneth; Zhao, Hongjie

    1992-01-01

    We have collected an extensive polarization lidar dataset from elevated sites in the Tushar Mountains of Utah in support of winter storm cloud seeding research and experiments. Our truck-mounted ruby lidar collected zenith, dual-polarization lidar data through a roof window equipped with a wiper system to prevent snowfall accumulation. Lidar returns were collected at a rate of one shot every 1 to 5 min during declared storm periods over the 1985 and 1987 mid-Jan. to mid-Mar. Field seasons. The mid-barrier remote sensor field site was located at 2.57 km MSL. Of chief interest to weather modification efforts are the heights of supercooled liquid water (SLW) clouds, which must be known to assess their 'seedability' (i.e., temperature and height suitability for artificially increasing snowfall). We are currently re-examining out entire dataset to determine the climatological properties of SLW clouds in winter storms using an autonomous computer algorithm.

  15. Redistribution of Snowfall across a Mountain Range by Artificial Seeding: A Case Study.

    PubMed

    Hobbs, P V; Radke, L F

    1973-09-14

    Clouds over the western slopes of the Cascade Mountains were artificially seeded to reduce the riming and fall speeds of snow crystals and to divert snowfall across the crest. Aircraft observations showed that the clouds were glaciated by the seeding. The crystal habits and the degrees of riming of snow crystals reaching the target area were modified. Snowfall rates decreased at the crest and simultaneously increased 20 kilometers east of the crest. PMID:17731264

  16. Variations of ice nuclei concentration induced by rain and snowfall within a local forested site in Japan

    NASA Astrophysics Data System (ADS)

    Hara, Kazutaka; Maki, Teruya; Kobayashi, Fumihisa; Kakikawa, Makiko; Wada, Masashi; Matsuki, Atsushi

    2016-02-01

    Biological ice nuclei (IN) such as certain species of bacteria and fungi are believed to have impacts on ice nucleation in mixed-phase clouds at temperatures warmer than -15 °C. Recent studies have indicated that rain is closely related to increases of biological IN in the near-surface atmosphere. However, variations of IN concentrations during rain and snowfall have not been compared. In the present study, field measurements of atmospheric IN were carried out under fine, cloudy, rain and snow at a local forested site in Japan. IN concentrations at -7 °C in spring were dramatically increased by rain, and concentrations associated with rain (0.86-2.2 m-3) were greater than 2.6 times higher than the mean concentration during fine weather (0.33 m-3). In winter, concentrations associated with rain (1.6 to >5.7 m-3) were also higher than those under cloudy sky (1.1 m-3), but increases were not observed during snowfall (0.21-0.4 m-3). Detectable IN concentrations associated with rain considerably decreased after heat treatment at 90 °C, indicating that IN increased during rain were likely biological substances such as heat-sensitive ice nucleation active proteins. Consequently, different types of precipitation may have varying effects on IN concentration associated with biological substances.

  17. Cold temperature increases winter fruit removal rate of a bird-dispersed shrub.

    SciTech Connect

    Charles Kwit; Douglas J. Levey; Cathryn H. Greenberg; Scott F. Pearson; John P. McCarty; Sarah Sargent

    2004-01-10

    Kwit, C., D. J. Levey; C. H. Greenberg, S. F. Pearson, J.P. McCarty, and S. Sargent. Cold temperature increases winter fruit removal rate of a bird-dispersed shrub. Oecologia. 139:30-34. Abstract: We tested the hypothesis that winter removal rates of fruits of wax myrtle, Myrica cerifera, are higher in colder winters. Over a 9-year period, we monitored M. cerifera fruit crops in 13 0.1-ha study plots in South Carolina, U.S.A. Peak ripeness occurred in November, whereas peak removal occurred in the coldest months, December and January. Mean time to fruit removal within study plots was positively correlated with mean winter temperatures, thereby supporting our hypothesis. This result, combined with the generally low availability of winter arthropods, suggests that fruit abundance may play a role in determining winter survivorship and distribution of permanent resident and short-distance migrant birds. From the plant's perspective, it demonstrates inter-annual variation in the temporal component of seed dispersal, with possible consequences for post-dispersal seed and seedling ecology.

  18. Circulation patterns governing October snowfalls in southern Siberia

    NASA Astrophysics Data System (ADS)

    Bednorz, Ewa; Wibig, Joanna

    2015-12-01

    This study is focused on early fall season in southern Siberia (50-60 N) and is purposed as a contribution to the discussion on the climatic relevance of October Eurasian snow cover. Analysis is based on the daily snow depth data from 43 stations from years 1980-2012, available in the database of All-Russian Research Institute of Hydrometeorological Information—World Data Centre. The snow cover season in southern Siberia starts in early autumn and the number of days with snowfall varies from less than 5 days in the southernmost zone along the parallel 50 N to more than 25 days in the northeastern part of the analyzed area. October snowfall in southern Siberia is associated with occurrence of negative anomalies of sea level pressure (SLP), usually spreading right over the place of recorded intense snowfall or extending eastward from it. Negative anomalies of air temperature at the 850 hPa geopotential level (T850) occurring with increased cyclonic activity are also observed. Negative T850 anomalies are located west or northwest of the SLP depressions. Counterclockwise circulation around low-pressure systems transports cold Arctic air from the north or even colder Siberian polar air from the east, to the west, and northwest parts of cyclones, and induces negative anomalies of temperature. The pattern of T850 anomalies during heavy snowfalls in the eastern part of the southern Siberia is shifted counterclockwise in regard to SLP anomalies: the strongest negative T850 anomalies are located west or northwest of the SLP depressions.

  19. Multiyear Evidence from Ground-based Observations and Modeling of the Impact of Dust on Snowfall in the Sierra Nevada

    NASA Astrophysics Data System (ADS)

    Creamean, J.; Ault, A. P.; Collins, D. B.; Cahill, J. F.; Fitzgerald, E.; White, A. B.; Neiman, P. J.; Wick, G. A.; Fan, J.; Leung, L.; Ralph, F. M.; Prather, K. A.

    2011-12-01

    Aerosols that have the ability to act as ice nuclei (IN) can impact cloud formation and alter the type, amount, and location of precipitation. IN such as dust and biological aerosols can lead to early initiation of the ice phase that enhances riming and thus precipitation. Depending on temperature conditions, this can lead to increased snowfall at the surface. Potential snowfall enhancement in mountainous regions such as California's Sierra Nevada has large implications on regional water supply, which in turn can affect agricultural and ecosystem productivity, the amount of renewable energy from hydropower, and many other water uses. However, the magnitude of the effect of IN on precipitation intensity, form, and patterns during intense winter storms in the Sierra Nevada is poorly understood. During three consecutive winters (2009-2011) of the CalWater field campaign, the chemical composition of precipitation residues were measured at Sugar Pine Dam, a remote rural site in the Sierra Nevada. Some precipitation events occurred during storms that were characterized by atmospheric river (AR) conditions, which are ideal for generating copious amounts of orographic precipitation. Large fractions of dust and biological aerosols were measured as residues in precipitation samples collected during storms with increased snowfall and lower surface temperatures. In most cases, higher fractions of dust were measured in samples during stronger ARs, while higher fractions of biological or water-insoluble organic residues were measured during weaker ARs throughout all three winters. During the winter storms of CalWater, we observed an increase over time in the fraction of dust and biological residues combined, from 20% in 2009 to 82% in 2011 of the total residues in all precipitation samples, in addition to a decrease in average surface temperature (from 4.8 to 2.3 °C), an increase in the total amount of precipitation (from 253 to 374 mm), and an increase in the frequency of

  20. An assessment of the changing nature of the winter hydroclimate in eastern North America and its impacts on risk management

    NASA Astrophysics Data System (ADS)

    Moore, Kent

    2016-04-01

    The winter hydroclimate of eastern North America is characterized by a complex and spatially varying combination of snow and rain. Much of this complexity stems from the presence of Great Lakes that are a source of heat and moisture during the winter months. Lake effect snowfall can result in heavy snowfall in highly localized regions downstream of the lakes. In addition the average mean winter temperature in the region is close to freezing and so there is enhanced sensitivity as to the phase of the precipitation. The region has warmed by 1-2.5 oC during the winter over the past 30 years and so there is concern that the character of the winter hydroclimate may be changing. Here we use reanalysis fields as well as the results of AMIP model runs, with horizontal resolutions ranging from 100 km to 16 km, to investigate the changes that have occurred in the winter hydroclimate of the region. It is shown that a horizontal resolution below ~40 km is needed to resolve the observed spatial gradients in snowfall and rainfall in the region. Over the past 30 years, the mean and 95th percentile snowfall rates in the southern part of the region have decreased by as much as 20% with an increase of a similar magnitude in both these parameters in its northwest. There has also been an increase in the mean and 95th percentile rainfall rates across much the region that exceeds 100% in the vicinity of Lake Superior, the largest and most northern of the Great Lakes. These changes are attributed to the warming that the region has experienced and are expected to continue into the future. They have and will continue to impact a number of societal functions including winter road maintenance as well as influencing the management of property risks such as flooding.

  1. Polarimetric radar and in situ observations of riming and snowfall microphysics during CLACE 2014

    NASA Astrophysics Data System (ADS)

    Grazioli, J.; Lloyd, G.; Panziera, L.; Hoyle, C. R.; Connolly, P. J.; Henneberger, J.; Berne, A.

    2015-12-01

    This study investigates the microphysics of winter alpine snowfall occurring in mixed-phase clouds in an inner-Alpine valley during January and February 2014. The available observations include high-resolution polarimetric radar and in situ measurements of the ice-phase and liquid-phase components of clouds and precipitation. Radar-based hydrometeor classification suggests that riming is an important factor to favor an efficient growth of the precipitating mass and correlates with snow accumulation rates at ground level. The time steps during which rimed precipitation is dominant are analyzed in terms of temporal evolution and vertical structure. Snowfall identified as rimed often appears after a short time period during which the atmospheric conditions favor wind gusts and updrafts and supercooled liquid water (SLW) is available. When a turbulent atmospheric layer persists for several hours and ensures continuous SLW generation, riming can be sustained longer and large accumulations of snow at ground level can be generated. The microphysical interpretation and the meteorological situation associated with one such event are detailed in the paper. The vertical structure of polarimetric radar observations during intense snowfall classified as rimed shows a peculiar maximum of specific differential phase shift Kdp, associated with large number concentrations and riming of anisotropic crystals. Below this Kdp peak there is usually an enhancement in radar reflectivity ZH, proportional to the Kdp enhancement and interpreted as aggregation of ice crystals. These signatures seem to be recurring during intense snowfall.

  2. Impacts of air-sea exchange coefficients on snowfall events over the Korean Peninsula

    NASA Astrophysics Data System (ADS)

    Kang, Jung-Yoon; Kwon, Young Cheol

    2016-08-01

    Snowfall over the Korean Peninsula is mainly associated with air mass transformation by the fluxes across the air-sea interface during cold-air outbreaks over the warm Yellow Sea. The heat and momentum exchange coefficients in the surface flux parameterization are key parameters of flux calculations across the air-sea interface. This study investigates the effects of the air-sea exchange coefficients on the simulations of snowfall events over the Korean Peninsula using the Weather Research and Forecasting (WRF) model. Two snowfall cases are selected for this study. One is a heavy snowfall event that took place on January 4, 2010, and the other is a light snowfall event that occurred on December 23-24, 2011. Several sensitivity tests are carried out with increased and decreased heat and momentum exchange coefficients. The domain-averaged precipitation is increased (decreased) with increased (decreased) heat exchange coefficient because the increased (decreased) surface heat flux leads to more (less) moist conditions in the low level of the atmosphere. On the other hand, the domain-averaged precipitation is decreased (increased) with increased (decreased) momentum exchange coefficient because the increased (decreased) momentum coefficient causes reduction (increase) of wind speed and heat flux. The variation of precipitation in the heat exchange coefficient experiments is much larger than that in the momentum exchange coefficient experiments because the change of heat flux has a more direct impact on moisture flux and snowfall amount, while the change of momentum flux has a rather indirect impact via wind speed changes. The low-pressure system is intensified and moves toward North when the heat exchange coefficient is increased because warming and moistening of the lower atmosphere contributes to destabilize the air mass, resulting in the change of precipitation pattern over the Korean Peninsula in the heat exchange coefficient experiments.

  3. Snowfall and avalanche synchronization: beyond observational statistics

    NASA Astrophysics Data System (ADS)

    Crouzy, Benoît; Forclaz, Romain; Sovilla, Betty; Corripio, Javier; Perona, Paolo

    2015-04-01

    We present a methodology for quantifying the synchronization between snowfall and avalanches in relation to slope and terrain properties at the detachment zone. Focusing on a particular field situation (SLF study site, Vallée de la Sionne, Valais, Switzerland), we present a dataset consisting of 549 avalanche events and use a stochastic framework (Perona et al., Proceedings of the Royal Society A, 2012) for capturing the avalanche statistics with a minimal number of ingredients. Over the observation period (7 years), meteorological data was collected and pictures of the slope were taken every 30 minutes. For the avalanche events, slope, aspect, coordinates and altitude of the detachment zone are available from georeferenced images, and the timing of the events can be obtained from selecting the images before and after avalanche events. All model parameters can directly be computed from meteorological data (snow depth evolution), except for one parameter: the state-dependent avalanche release rate, which aggregates the influence of slope and terrain properties. From the timing distribution of the precipitation events and of the avalanche events, we calibrate the model and fix the value of the missing parameter by maximizing the likelihood of the field observations, conditional to the value of the model parameter. We carefully discuss confidence intervals for our parameter estimation. The calibrated model allows us to obtain statistical properties of the avalanches in our study site, beyond observational statistics. We compute the synchronization between snowfall and avalanches for low and high slopes, which in turn allows us to derive the return period of avalanche events (dependent and independent on the release depth). We obtain the critical event magnitude above which the return period of avalanche events with release depth h* is shorter than the return period of snowfall with equal deposited snow depth h*. Finally, using the concept of information entropy, we

  4. Snowfall Rate Retrieval using NPP ATMS Passive Microwave Measurements

    NASA Technical Reports Server (NTRS)

    Meng, Huan; Ferraro, Ralph; Kongoli, Cezar; Wang, Nai-Yu; Dong, Jun; Zavodsky, Bradley; Yan, Banghua; Zhao, Limin

    2014-01-01

    Passive microwave measurements at certain high frequencies are sensitive to the scattering effect of snow particles and can be utilized to retrieve snowfall properties. Some of the microwave sensors with snowfall sensitive channels are Advanced Microwave Sounding Unit (AMSU), Microwave Humidity Sounder (MHS) and Advance Technology Microwave Sounder (ATMS). ATMS is the follow-on sensor to AMSU and MHS. Currently, an AMSU and MHS based land snowfall rate (SFR) product is running operationally at NOAA/NESDIS. Based on the AMSU/MHS SFR, an ATMS SFR algorithm has been developed recently. The algorithm performs retrieval in three steps: snowfall detection, retrieval of cloud properties, and estimation of snow particle terminal velocity and snowfall rate. The snowfall detection component utilizes principal component analysis and a logistic regression model. The model employs a combination of temperature and water vapor sounding channels to detect the scattering signal from falling snow and derive the probability of snowfall (Kongoli et al., 2014). In addition, a set of NWP model based filters is also employed to improve the accuracy of snowfall detection. Cloud properties are retrieved using an inversion method with an iteration algorithm and a two-stream radiative transfer model (Yan et al., 2008). A method developed by Heymsfield and Westbrook (2010) is adopted to calculate snow particle terminal velocity. Finally, snowfall rate is computed by numerically solving a complex integral. The ATMS SFR product is validated against radar and gauge snowfall data and shows that the ATMS algorithm outperforms the AMSU/MHS SFR.

  5. CHARACTERISTICS OF ACIDITY AND MAJOR ION CONCENTRATION OF SNOWFALL, SNOWPACK AND SNOWMELT WATER IN THE TEMPERATE SNOW AREA

    NASA Astrophysics Data System (ADS)

    Asaoka, Yoshihiro; Takeuchi, Yukari

    This paper describes the acidity and main ion concentration of snowfall, snowpack and snowmelt water in the temperate snow area. In order to understand the variation of snow water quality and its relationship among snow, snowpack and snowmelt, snow monitoring and chemical measurement were conducted from December 2008 to March 2009 at Tohkamachi experiment site. As a result, the both of snowfall and snowmelt were high acidity and their average were around 4.6 and 5.0, individually. However, high frequencies of rainfall and snowmelt occurrence during winter decrease the high acidity of snowpack and snowmelt water since they prevent the chemical matter from depositing in the snowpack layer. Moreover, it is suspected that the soil component from Eurasia continent contained in the snow particle also decrease the high acidity of snowfall and snowpack.

  6. Analysis of a snowfall event produced by mountains waves in Guadarrama Mountains (Spain)

    NASA Astrophysics Data System (ADS)

    Gascón, Estíbaliz; Sánchez, José Luis; Fernández-González, Sergio; Merino, Andrés; López, Laura; García-Ortega, Eduardo

    2014-05-01

    Heavy snowfall events are fairly uncommon precipitation processes in the Iberian Peninsula. When large amounts of snow accumulate in large cities with populations that are unaccustomed to or unprepared for heavy snow, these events have a major impact on their daily activities. On 16 January 2013, an extreme snowstorm occurred in Guadarrama Mountains (Madrid, Spain) during an experimental winter campaign as a part of the TECOAGUA Project. Strong northwesterly winds, high precipitation and temperatures close to 0°C were detected throughout the whole day. During this episode, it was possible to continuously take measurements of different variables involved in the development of the convection using a multichannel microwave radiometer (MMWR). The significant increase in the cloud thickness observed vertically by the MMWR and registered precipitation of 43 mm in 24 hours at the station of Navacerrada (Madrid) led us to consider that we were facing an episode of strong winter convection. Images from the Meteosat Second Generation (MSG) satellite suggested that the main source of the convection was the formation of mountain waves on the south face of the Guadarrama Mountains. The event was simulated in high resolution using the WRF mesoscale model, an analysis of which is based on the observational simulations and data. Finally, the continuous measurements obtained with the MMWR allowed us to monitor the vertical situation above the Guadarrama Mountains with temporal resolution of 2 minutes. This instrument has a clear advantage in monitoring short-term episodes of this kind in comparison to radiosondes, which usually produce data at 0000 and 1200 UTC. Acknowledgements This study was supported by the following grants: GRANIMETRO (CGL2010-15930); MICROMETEO (IPT-310000-2010-22). The authors would like to thank the Regional Government of Castile-León for its financial support through the project LE220A11-2.

  7. Characteristics of easterly-induced snowfall in Yeongdong and its relationship to air-sea temperature difference

    NASA Astrophysics Data System (ADS)

    Nam, Hyoung-Gu; Kim, Byung-Gon; Han, Sang-Ok; Lee, Chulkyu; Lee, Seoung-Soo

    2014-08-01

    Characteristics of snowfall episodes have been investigated for the past ten years in order to study its association with lowlevel stability and air-sea temperature difference over the East Sea. In general, the selected snowfall episodes have similar synoptic setting such as the Siberian High extended to northern Japan along with the Low passing by the southern Korean Peninsula, eventually resulting in the easterly flow in the Yeongdong region. Especially in the heavy snowfall episodes, convective unstable layers have been identified over the East sea due to relatively warm sea surface temperature (SST) about 8˜10°C and specifically cold pool around 1˜2 km above the surface level (ASL), which can be derived from Regional Data Assimilation and Prediction System (RDAPS), but that have not been clearly exhibited in the weak snowfall episodes. The basic mechanism to initiate snowfall around Yeongdong seems to be similar to that of lake-effect snowstorms around Great Lakes in the United States (Kristovich et al., 2003). Difference of equivalent potential temperature ( θ e ) between 850 hPa and surface as well as difference between air and sea temperatures altogether gradually began to increase in the pre-snowfall period and reached their maximum values in the course of the period, whose air (850 hPa) — sea temperature difference and snowfall intensity in case of the heavy snowfall episodes are almost larger than 20°C and 6 tims greater than the weak snowfall episodes, respectively. Interestingly, snowfall appeared to begin in case of an air-sea temperature difference exceeding over 15°C. The current analysis is overall consistent with the previous finding (Lee et al., 2012) that an instabilityinduced moisture supply to the lower atmosphere from the East sea, being cooled and saturated in the lower layer, so to speak, East Sea-Effect Snowfall (SES), would make a low-level ice cloud which eventually moves inland by the easterly flow. In addition, a longlasting

  8. Increasing late winter-early spring fire activity in Northern Spain: climate change or human footprint?

    NASA Astrophysics Data System (ADS)

    Carracedo Martín, Virginia; García Codron, Juan Carlos; Rasilla Álvarez, Domingo

    2016-04-01

    Most of the fire activity across Spain concentrates during the summer months, but a secondary peak appears also during late winter and early spring (February and March). This peak represents a tiny fraction of the burned surface but in northern Spain becomes the main fire season, representing up to 60 % of the total burned surface. Moreover, the impact of this "unseasonal" fire regime is becoming more relevant; an analysis of the temporal evolution of the burned surface since 2005 shows that the suppression efforts of summer forest fires have apparently succeeded, while the opposite has occurred with late winter-early spring forest fires. For example, during March 2012 more than 22,000 ha were burned in the Spanish provinces of Asturias and Cantabria, while about 14,000 suffers the effects of fires in Northern Portugal. Anthropogenic factor (mostly linked to an extensive cattle farming in the mountains) are the main cause of such fire activity, but atmospheric factors also play a relevant role in the spread of this fires. Consequently, the main aim of this poster is to explore if the recent evolution of forest fires in the study area are consequence of an aggravation of the atmospheric conditions driving to more fire risk conditions, or other factor could also explain the increase in fire activity. Burned surface data obtained from official statistics since 1971 were compared with atmospheric data at two temporal scales: daily fire risk values calculated from synoptic records and long term drought indices (SPI and SPEI). The results show a long term increase in both daily fire risk and drought conditions, but this trend can be related to the background warming of the area, rather to an increase in the frequency and magnitude of the extreme fire weather events. Thus, we consider that the regional atmospheric evolution cannot explain by itself the recent increase in late winter-early spring fire activity. Additional anthropogenic factors, such as recent changes in

  9. Altered snowfall and soil disturbance influence the early life stage transitions and recruitment of a native and invasive grass in a cold desert.

    PubMed

    Gornish, Elise S; Aanderud, Zachary T; Sheley, Roger L; Rinella, Mathew J; Svejcar, Tony; Englund, Suzanne D; James, Jeremy J

    2015-02-01

    Climate change effects on plants are expected to be primarily mediated through early life stage transitions. Snowfall variability, in particular, may have profound impacts on seedling recruitment, structuring plant populations and communities, especially in mid-latitude systems. These water-limited and frequently invaded environments experience tremendous variation in snowfall, and species in these systems must contend with harsh winter conditions and frequent disturbance. In this study, we examined the mechanisms driving the effects of snowpack depth and soil disturbance on the germination, emergence, and establishment of the native Pseudoroegnaria spicata and the invasive Bromus tectorum, two grass species that are widely distributed across the cold deserts of North America. The absence of snow in winter exposed seeds to an increased frequency and intensity of freeze-thaw cycles and greater fungal pathogen infection. A shallower snowpack promoted the formation of a frozen surface crust, reducing the emergence of both species (more so for P. spicata). Conversely, a deeper snowpack recharged the soil and improved seedling establishment of both species by creating higher and more stable levels of soil moisture availability following spring thaw. Across several snow treatments, experimental disturbance served to decrease the cumulative survival of both species. Furthermore, we observed that, regardless of snowpack treatment, most seed mortality (70-80%) occurred between seed germination and seedling emergence (November-March), suggesting that other wintertime factors or just winter conditions in general limited survival. Our results suggest that snowpack variation and legacy effects of the snowpack influence emergence and establishment but might not facilitate invasion of cold deserts. PMID:25539620

  10. Riming in alpine snowfall during CLACE 2014: Polarimetric radar and in situ observations

    NASA Astrophysics Data System (ADS)

    Grazioli, Jacopo; Berne, Alexis

    2016-04-01

    Riming occurs when ice crystals or snowflakes encounter supercooled liquid water (SLW) droplets during their fall to the surface within a mixed-phase cloud. It is an efficient mechanism to convert cloud liquid droplets to precipitating ice particles, frequently seen in snowfall in the mid-latitude regions. This study investigates the microphysics of winter alpine snowfall occurring in mixed-phase clouds in an inner-Alpine valley during January and February 2014. The available observations include high-resolution polarimetric radar and in situ measurements of the ice-phase and liquid-phase components of clouds and precipitation. Radar-based hydrometeor classification suggests that riming is an important factor to favour an efficient growth of the precipitating mass and correlates with snow accumulation rates at ground level. The time steps during which rimed precipitation is dominant are analyzed in terms of temporal evolution and vertical structure. Snowfall identified as rimed often appears after a short time period during which the atmospheric conditions favour wind gusts and updrafts and supercooled liquid water (SLW) is available. When a turbulent atmospheric layer persists for several hours and ensures continuous SLW generation, riming can be sustained longer and large accumulations of snow at ground level can be generated. The microphysical interpretation and the meteorological situation associated with one such event are detailed in the presentation.

  11. Linking snowfall and snow accumulation to generate spatial maps of SWE and snow depth

    NASA Astrophysics Data System (ADS)

    Broxton, Patrick D.; Dawson, Nicholas; Zeng, Xubin

    2016-06-01

    It is critically important but challenging to estimate the amount of snow on the ground over large areas due to its strong spatial variability. Point snow data are used to generate or improve (i.e., blend with) gridded estimates of snow water equivalent (SWE) by using various forms of interpolation; however, the interpolation methodologies often overlook the physical mechanisms for the snow being there in the first place. Using data from the Snow Telemetry and Cooperative Observer networks in the western United States, we show that four methods for the spatial interpolation of peak of winter snow water equivalent (SWE) and snow depth based on distance and elevation can result in large errors. These errors are reduced substantially by our new method, i.e., the spatial interpolation of these quantities normalized by accumulated snowfall from the current or previous water years. Our method results in significant improvement in SWE estimates over interpolation techniques that do not consider snowfall, regardless of the number of stations used for the interpolation. Furthermore, it can be used along with gridded precipitation and temperature data to produce daily maps of SWE over the western United States that are comparable to existing estimates (which are based on the assimilation of much more data). Our results also show that not honoring the constraint between SWE and snowfall when blending in situ data with gridded data can lead to the development and propagation of unrealistic errors.

  12. Decadal increase of organic compounds in winter and spring atmospheric aerosols in East Asia

    NASA Astrophysics Data System (ADS)

    Kundu, S.; Kawamura, K.; Kobayashi, M.; Tachibana, E.; Lee, M.; Jung, J.

    2014-12-01

    A rapid economic growth in China and other East Asian countries may have changed molecular level organic composition of atmospheric aerosols in East Asia. Molecular level composition is required to better evaluate the roles of organic aersols on climate, air quality and public health. Diacids and oxoacids account for a significant fraction of atmospheric organic matter and their secondary sources are more important than their primary sources. Atmospheric aerosol samples (n = 698) were collected during 2001-2008 at Gosan site in Jeju Island, South Korea. They were analyzed for saturated (C2-C10), unsaturated aliphatic (C4-C5), multifunctional (C3-C7) and aromatic (C8) diacids and oxoacids (C2-C9). According to monthly average concentration, oxalic acid (C2) is the most abundant followed by malonic acid (C3) and succinic acid (C4) in the homologous series of saturated diacids (C2-C10) whereas glyoxylic acid (ωC2) is most abundant in the homologous series of oxoacids (C2-C9). The monthly median, 25th percentile and 75th percentile concentrations of saturated and multifunctional diacids and oxoacids showed the highest in spring (March-May). In contrast, those concentrations for unsaturated aliphatic and aromatic diacids were observed the highest in winter (December-February). The monthly median and percentile (25th and 75th) concentrations of all diacids and oxoacids showed the second peak in the autumn (September-November) while those concentrations were recorded lowest in summer (June-August). A steady increment or decrement was not found in the monthly median and percentile (25th and 75th) concentrations of diacids and oxoacids in any month. However, the curve fitting of those concentrations over the study period shows an incremental trend for major diacids and oxoacids in winter and spring. For example, the monthly median, 25th percentile and 75th percentile concentrations of all major diacids and oxoacids increased up to 3 times from 2001 to 2008 in winter and

  13. Summer-Winter Hemispheric Asymmetry of Sudden Increase in Ionospheric Total Electron Content

    NASA Astrophysics Data System (ADS)

    Tsugawa, T.; Zhang, S.; Coster, A.; Otsuka, Y.; Sato, J.; Saito, A.; Zhang, Y.; Paxton, L.

    2006-12-01

    Sudden increases in total electron content (SITEC) induced by intense solar flares and their relation to O/N2 density ratio were statistically studied using data of GPS networks, TIMED/GUVI, and NRLMSISE-00 model. SITEC is one of sudden ionospheric disturbances induced by solar flares, which emit extreme ultraviolet and X rays in short time interval. The recently developed imaging technique using TEC data from GPS receiver networks has been applied to study SITEC and have clarified some of global-scale characteristics of SITEC phenomena [e.g., Afraimovich et al., 2001; Zhang and Xiao, 2003, 2005]. However, seasonal, local-time, and solar-cycle dependencies of SITEC have been still in dispute. In this study, we investigated 91 SITEC events associated with solar flares larger than M5 X-ray class during January 2000 and May 2005 global TEC data from SOPAC GPS networks. The global TEC maps revealed that the SITEC value basically depends on the cosine of solar zenith angle (SZA). However, we found that there were significant residuals (delta) from the linear fitting to the SZA for almost all the flare events. The value of delta is statistically larger in the winter hemisphere than in the summer hemisphere. The strength of summer-winter hemispheric asymmetry becomes weaker as the solar cycle declines toward its minimum. On the other hand, there is not a clear statistical difference in delta between the morning and evening sectors. Some similarity of summer-winter asymmetry is also seen in the dayside distribution of the O/N2 density ratio from both the NRLMSISE-00 model and the TIMED/GUVI observation. The latitudinal gradient of GUVI O/N2 at the solstice becomes smaller to follow the increasing solar activity in the same way as that of the residual SITEC delta. These results indicate that the SITEC phenomena induced by intense solar flares depend on not only the SZA, but also the O/N2 density ratio.

  14. [Distribution of PGEs contents and its factors in snowfall and snow cover over the arid region in Changji City].

    PubMed

    Liu, Yu-Yan; Liu, Hao-Feng; Zhang, Lan

    2013-02-01

    This paper was to select a small-medium sized City, Changji city, over the arid region, study the distribution of platinum group metals(PGEs) contents and influencing factors in snowfall and snow cover. Samples were analysed by ICP-MS. The results revealed that the annual contents of Rh, Pd and Pt in snowfall were on the average value of 0.43 ng.L-1 ranging from not detected to 2.24 ng.L-1 , 60.07 ng.L-1 ranging from 46.66 to 84.25 ng.L-1 and 4.54 ng.L-1 ranging from 3.02 ng.L-1 to 6.38 ng.L-1 respectively. The difference of PGEs levels was found in different occurrences of snowfall, tended to increase before snowfall due to the longer arid days. PGEs contents maybe influenced by the amount of snowfall, the less snowfall, the higher PGEs contents reflected. The annual levels of Rh, Pd and Pt in snow cover were in the range of 2.50-18.80 ng.L-1 (av. 6.65 ng.L-1), 46.83-199.20 ng.L-1 (av. 83.45 ng.L-1) ,4. 27-13.78 ng.L-1 (av. 8.17 ng.L-1) respectively. PGEs content in snow cover were far higher than that of snowfall, PGEs in snowfall were only obtained from atmospheric PGEs rinsed by single time of snowfall, while PGEs were not only from the accumulation of PGEs in frequent times of snowfall and the snow cover under the long time exposure, but also continuously accepted the PGEs from atmospheric dry deposition. PGEs content of snow cover in all sampling sites were demonstrated as follows: traffic area > residential-culture-education district > square of park > suburban farmland. the input way of PGEs in snow cover was found a remarkable difference with the amount of input within different function areas, which was the main reason caused that PGEs content of snow cover in each function area varied and had a certain regularity. PMID:23668114

  15. Cultivar Mixture Cropping Increased Water Use Efficiency in Winter Wheat under Limited Irrigation Conditions

    PubMed Central

    Wang, Yunqi; Zhang, Yinghua; Ji, Wei; Yu, Peng; Wang, Bin; Li, Jinpeng; Han, Meikun; Xu, Xuexin; Wang, Zhimin

    2016-01-01

    The effects of cultivar mixture cropping on yield, biomass, and water use efficiency (WUE) in winter wheat (Triticum aestivum L.) were investigated under non-irrigation (W0, no irrigation during growth stage), one time irrigation (W1, irrigation applied at stem elongation) and two times irrigation (W2, irrigation applied at stem elongation and anthesis) conditions. Nearly 90% of cultivar mixture cropping treatments experienced an increase in grain yield as compared with the mean of the pure stands under W0, those for W1 and W2 were 80% and 85%, respectively. Over 75% of cultivar mixture cropping treatments got greater biomass than the mean of the pure stands under the three irrigation conditions. Cultivar mixture cropping cost more water than pure stands under W0 and W1, whereas the water consumption under W2 decreased by 5.9%–6.8% as compared with pure stands. Approximately 90% of cultivar mixtures showed an increase of 5.4%–34.5% in WUE as compared with the mean of the pure stands, and about 75% of cultivar mixtures had 0.8%–28.5% higher WUE than the better pure stands under W0. Similarly, there were a majority of mixture cropping treatments with higher WUE than the mean and the better one of the pure stands under W1 and W2. On the whole, proper cultivar mixture cropping could increase yield and WUE, and a higher increase in WUE occurred under limited irrigation condition. PMID:27362563

  16. Increased winter soil temperature variability enhances nitrogen cycling and soil biotic activity in temperate heathland and grassland mesocosms

    NASA Astrophysics Data System (ADS)

    Schuerings, J.; Jentsch, A.; Hammerl, V.; Lenz, K.; Henry, H. A. L.; Malyshev, A. V.; Kreyling, J.

    2014-12-01

    Winter air temperatures are projected to increase in the temperate zone, whereas snow cover is projected to decrease, leading to increased soil temperature variability, and potentially to changes in nutrient cycling. Here, we experimentally evaluated the effects of increased winter soil temperature variability on selected aspects of the N-cycle in mesocosms containing different plant community compositions. The experiment was replicated at two sites, a colder mountainous upland site with high snow accumulation and a warmer and drier lowland site. Increased soil temperature variability enhanced soil biotic activity for both sites during winter, as indicated by 35% higher nitrogen (N) availability in the soil solution, 40% higher belowground decomposition and a 25% increase in the potential activity of the enzyme cellobiohydrolase. The mobilization of N differed between sites, and the 15N signal in leaves was reduced by 31% in response to winter warming pulses, but only at the cold site, with significant reductions occurring for three of four tested plant species at this site. Furthermore, there was a trend of increased N leaching in response to the recurrent winter warming pulses. Overall, projected winter climate change in the temperate zone, with less snow and more variable soil temperatures, appears important for shifts in ecosystem functioning (i.e. nutrient cycling). While the effects of warming pulses on plant N mobilization did not differ among sites, reduced plant 15N incorporation at the colder temperate site suggests that frost damage may reduce plant N uptake in a warmer world, with important implications for nitrogen cycling and nitrogen losses from ecosystems.

  17. Effect of reduced winter precipitation and increased temperature on watershed solute flux, 1988-2002, Northern Michigan

    USGS Publications Warehouse

    Stottlemyer, R.; Toczydlowski, D.

    2006-01-01

    Since 1987 we have studied weekly change in winter (December-April) precipitation, snowpack, snowmelt, soil water, and stream water solute flux in a small (176-ha) Northern Michigan watershed vegetated by 65-85 year-old northern hardwoods. Our primary study objective was to quantify the effect of change in winter temperature and precipitation on watershed hydrology and solute flux. During the study winter runoff was correlated with precipitation, and forest soils beneath the snowpack remained unfrozen. Winter air temperature and soil temperature beneath the snowpack increased while precipitation and snowmelt declined. Atmospheric inputs declined for H+, NO 3- , NH 4+ , dissolved inorganic nitrogen (DIN), and SO 42- . Replicated plot-level results, which could not be directly extrapolated to the watershed scale, showed 90% of atmospheric DIN input was retained in surface shallow (<15 cm deep) soils while SO 42- flux increased 70% and dissolved organic carbon (DOC) 30-fold. Most stream water base cation (C B), HCO 3- , and Cl- concentrations declined with increased stream water discharge, K+, NO 3- , and SO 42- remained unchanged, and DOC and dissolved organic nitrogen (DON) increased. Winter stream water solute outputs declined or were unchanged with time except for NO 3- and DOC which increased. DOC and DIN outputs were correlated with the percentage of winter runoff and stream discharge that occurred when subsurface flow at the plot-level was shallow (<25 cm beneath Oi). Study results suggest that the percentage of annual runoff occurring as shallow lateral subsurface flow may be a major factor regulating solute outputs and concentrations in snowmelt-dominated ecosystems. ?? Springer 2006.

  18. Snowfall-driven growth in East Antarctic ice sheet mitigates recent sea-level rise.

    PubMed

    Davis, Curt H; Li, Yonghong; McConnell, Joseph R; Frey, Markus M; Hanna, Edward

    2005-06-24

    Satellite radar altimetry measurements indicate that the East Antarctic ice-sheet interior north of 81.6 degrees S increased in mass by 45 +/- 7 billion metric tons per year from 1992 to 2003. Comparisons with contemporaneous meteorological model snowfall estimates suggest that the gain in mass was associated with increased precipitation. A gain of this magnitude is enough to slow sea-level rise by 0.12 +/- 0.02 millimeters per year. PMID:15905362

  19. Elevated streamflows increase dam passage by juvenile coho salmon during winter: Implications of climate change in the Pacific Northwest

    USGS Publications Warehouse

    Kock, Tobias J.; Liedtke, Theresa L.; Rondorf, Dennis W.; Serl, John D.; Kohn, Mike; Bumbaco, Karin A.

    2012-01-01

    A 4-year evaluation was conducted to determine the proportion of juvenile coho salmon Oncorhynchus kisutch passing Cowlitz Falls Dam, on the Cowlitz River, Washington, during winter. River and reservoir populations of coho salmon parr were monitored using radiotelemetry to determine if streamflow increases resulted in increased downstream movement and dam passage. This was of interest because fish that pass downstream of Cowlitz Falls Dam become landlocked in Riffe Lake and are lost to the anadromous population. Higher proportions of reservoir-released fish (0.391-0.480) passed Cowlitz Falls Dam than did river-released fish (0.037-0.119). Event-time analyses demonstrated that streamflow increases were important predictors of dam passage rates during the study. The estimated effect of increasing streamflows on the risk of dam passage varied annually and ranged from 9% to 75% for every 28.3 m3/s increase in streamflow. These results have current management implications because they demonstrate the significance of dam passage by juvenile coho salmon during winter months when juvenile fish collection facilities are typically not operating. The results also have future management implications because climate change predictions suggest that peak streamflow timing for many watersheds in the Pacific Northwest will shift from late spring and early summer to winter. Increased occurrence of intense winter flood events is also expected. Our results demonstrate that juvenile coho salmon respond readily to streamflow increases and initiate downstream movements during winter months, which could result in increased passage at dams during these periods if climate change predictions are realized in the coming decades.

  20. Ensemble Predictions of Future Snowfall Scenarios in the Karakorum and Hindu-Kush Mountains Using Downscaled GCM Data

    NASA Astrophysics Data System (ADS)

    Mosier, T. M.; Hill, D. F.; Sharp, K. V.

    2014-12-01

    Climate change is affecting the seasonality and mass of snow, and impacting the water resources of hundreds of millions of people who depend on streamflow originating in High Asia. Global climate model (GCM) outputs are the primary forcing data used to investigate future projections of changes in snow and glacier processes; however, these processes occur at a much finer spatial scale than the resolution of current GCMs. To facilitate studying the cryosphere in High Asia, we developed a software package to downscale monthly GCM data to 30-arcseconds for any global land area. Using this downscaling package, we produce an ensemble of downscaled GCM data from 2020-2100, corresponding to representative concentration pathways (RCPs) 4.5 and 8.5. We then use these data to model changes to snowfall in the Karakorum and Hindu Kush (KHK) region, which is located in High Asia. The ensemble mean of these data predict that total annual snowfall in 2095 will decrease by 22% under RCP 4.5 and 46% under RCP 8.5, relative to 1950-2000 climatological values. For both scenarios, the changes in snowfall are dependent on elevation, with the maximum decreases in snowfall occurring at approximately 2,300 m. While total snowfall decreases, an interesting feature of snowfall change for the RCP 8.5 scenario is that the ensemble mean projection shows an increase in snowfall for elevations between 3,000- 5,000 m relative to historic values. These fine-scale spatial, temporal, and elevation-dependent patterns of changes in projected snowfall significantly affect the energy balance of the snowpack, in turn affecting timing of melt and discharge. Therefore, our work can be coupled with a glacio-hydrological model to assess effects of these snowfall patterns on other processes or compared to existing model results to assess treatment of snow processes in the existing model. Our method is designed to downscale climate data for any global land area, allowing for the production of these fine

  1. Growth of the inner core by snowfall

    NASA Astrophysics Data System (ADS)

    Lasbleis, M.; Labrosse, S.; Hernlund, J. W.

    2012-12-01

    In past decades, seismic studies of the Earth's core have tremendously improved our knowledge of its structure. The solid inner core presents heterogeneity at all scales, including both regional and hemispherical variations in degree and possibly orientation of elastic anisotropy, small-scale scattering, and potential indications of internal layering. Seismic observations also reveal subtle changes in seismic velocity gradient at the bottom of the liquid outer core that has been interpreted as a stratified layer, depleted in light alloying elements. Gubbins et al. (GJI, 2008) proposed that such a layer could be at the liquidus throughout, however, the details of the process that gives rise to such a scenario and its dynamical evolution with time have not been elucidated. Here we propose a model of slurry (snowfall) inside the F-layer. We have formulated a binary alloy model for the nucleation, settling and chemical reaction of snow with surrounding fluid in which cooling and crystallization is driven at the top of a compositionally stratified F-layer. Our model reveals a simple dynamical feedback that could drive the system toward a state such that the entire stratified region is maintained at the liquidus. We find that diffusion is the dominant transport phenomenon inside the layer, between the freely convecting outer core and the inner core, for both temperature and composition. Owing to variations in heat flow with time imposed by mantle convection, the equilibrium between the geotherm and liquidus in the F-layer would be perturbed, and we derive time scales for enhanced melting or freezing of snow to return the layer to equilibrium.

  2. Measuring winter precipitation in a mountain catchment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measuring winter precipitation (principally snowfall) in a mountain catchment is difficult. The magnitude of gauge under catch is affected by variable density during deposition, wind speed and direction, and site conditions such as vegetation and topography. Though numerous studies have been condu...

  3. Maize Debris Increases Barley Yellow Dwarf Virus Severity in North Carolina Winter Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the eastern U.S., wheat is often planted with minimal or no tillage into maize residues. We conducted a field experiment in the North Carolina Piedmont to compare the effects of three maize residue treatments (unchopped, chopped, and removed) on Fusarium head blight (FHB) in two winter wheat cul...

  4. Characteristics of Heavy Snowfall and Snow Crystal Habits in the ESSAY (Experiment on Snow Storms At Yeongdong) Campaign in Korea

    NASA Astrophysics Data System (ADS)

    Seong, D. K.; Seok, S. W.; Eun, S. H.; Kim, B. G.; Reum, K. A.; Lee, K. M.; Jeon, H. R.; Byoung Choel, C.; Park, Y. S.

    2015-12-01

    Characteristics of heavy snowfall and snow crystal habits have been investigated in the campaign of Experiment on Snow Storms At Yeongdong (ESSAY) using radiosonde soundings, Global Navigation Satellite System (GNSS), and a digital camera with a magnifier for taking a photograph of snowfall crystals. The analysis period is mainly both winters of 2014 and 2015. The synoptic situations are similar to those of the previous studies such as the Low pressure system passing by the far South of the Korean peninsula along with the Siberian High extending to northern Japan, which eventually results in the northeasterly or easterly flows and the long-lasting snowfall episodes in the Yeongdong region. The snow crystal habits observed in the ESSAY campaign were mainly dendrite, consisting of 70% of the entire habits. The rimed habits were frequently captured when two-layered clouds were observed, probably through the process of freezing of super-cooled droplets on the ice particles. The homogeneous habit such as dendrite was shown in case of shallow clouds with its thickness of below 500 m whereas various habits were captured such as graupel, dendrites, rimed dendrites, aggregates of dendrites, plates, rimed plates, etc in the thick cloud with its thickness greater than 1.5 km. The dendrites appeared to be dominant in the condition of cloud top temperature specifically ranging -12~-16℃. Interestingly temporal evolutions of snow crystal habits were consistently shown for several snowfall events such as changes from rimed particles to dendrites(or aggregated dendrites). The association of snow crystal habits with temperature and super-saturation in the cloud will be in detail examined. However, better understandings of characteristics of snow crystal habits would contribute to preventing breakdown accidents such as a greenhouse destruction and collapse of a temporary building due to heavy snowfall, and traffic accidents due to snow-slippery road condition, providing a higher

  5. Iron-Superoxide Dismutase Expression in Transgenic Alfalfa Increases Winter Survival without a Detectable Increase in Photosynthetic Oxidative Stress Tolerance1

    PubMed Central

    McKersie, Bryan D.; Murnaghan, Julia; Jones, Kim S.; Bowley, Stephen R.

    2000-01-01

    To determine whether overexpression of Fe-superoxide (SOD) dismutase would increase superoxide-scavenging capacity and thereby improve the winter survival of transgenic alfalfa (Medicago sativa L.) plants, two genotypes were transformed with the vector pEXSOD10, which contains a cDNA for Arabidopsis Fe-SOD with a chloroplast transit peptide and cauliflower mosaic virus 35S promoter. A novel Fe-SOD was detected by native PAGE in both greenhouse- and field-grown transgenic plants, but activity varied among independent transgenic plants. The increased Fe-SOD activity was associated with increased winter survival over 2 years in field trials, but not with oxidative stress tolerance as measured by resistance of leaves to methyl viologen, a superoxide generator. Total shoot dry matter production over 2 harvest years was not associated with Fe-SOD activity. There was no detectable difference in the pattern of primary freezing injury, as shown by vital staining, nor was there additional accumulation of carbohydrates in field-acclimated roots of the transgenic alfalfa plants. We did not detect any difference in growth of one transgenic plant with high Fe-SOD activity compared with a non-transgenic control. Therefore, the improvement in winter survival did not appear to be a consequence of improved oxidative stress tolerance associated with photosynthesis, nor was it a consequence of a change in primary freezing injury. We suggest that Fe-SOD overexpression reduced secondary injury symptoms and thereby enhanced recovery from stresses experienced during winter. PMID:10759538

  6. Characteristics of Lightning within Electrified Snowfall Events using Total Lightning Measurements

    NASA Astrophysics Data System (ADS)

    Schultz, C. J.; Bruning, E. C.; Lang, T. J.; Kuhlman, K. M.

    2015-12-01

    Lightning within heavy snowfall indicates the presence of heavy snowfall rates. Most studies within the literature examine this phenomenon using ground based networks that are primarily designed for identifying cloud to ground flashes. Thus, very little study of the three dimensional structure of the lightning flashes within heavy snowfall has been accomplished. Herein, total lightning mapping arrays, interferometers and ground based networks like the National Lightning Detection Network (NLDN) are utilized to document the characteristics of these flashes, including flash size, polarity, flash initiation location and inferred charge structure. A total of six events are examined, resulting in a total of approximately 80 flashes. Both individual case studies and overall population statistics will be used to characterize flashes within this winter environment. Many of these flashes are found to initiate from tall objects like television and radio communication towers, and come to ground in multiple locations along their path, resulting in one LMA derived flash containing multiple NLDN identified flashes. Cloud-to-ground flashes of both polarities are noted within the 80 flash sample. In one case, 3 separate flashes which resulted in ground flashes of both polarities were observed coming out of the same overall charge structure. This structure exhibited a highly sloped nature in the LMA data from east to west, and both +IC and -IC components of flashes were observed by the NLDN in the same region where the flashes initiated. A decrease in flash size is noted with time in at least three of these events due to weaker updraft (compared to their summertime thunderstorm counter parts) and smaller available of supercooled liquid water as inferred through trends in radar observations. These limiting factors are hypothesized to result in slower charging rates, and smaller flash sizes with time. Several flashes also exhibit sloped structures that match reflectivity

  7. The Potential of Five Winter-grown Crops to Reduce Root-knot Nematode Damage and Increase Yield of Tomato

    PubMed Central

    López-Pérez, Jose Antonio; Roubtsova, Tatiana; de Cara García, Miguel

    2010-01-01

    Broccoli (Brassica oleracea), carrot (Daucus carota), marigold (Tagetes patula), nematode-resistant tomato (Solanum lycopersicum), and strawberry (Fragaria ananassa) were grown for three years during the winter in a root-knot nematode (Meloidogyne incognita) infested field in Southern California. Each year in the spring, the tops of all crops were shredded and incorporated in the soil. Amendment with poultry litter was included as a sub-treatment. The soil was then covered with clear plastic for six weeks and M. incognita-susceptible tomato was grown during the summer season. Plastic tarping raised the average soil temperature at 13 cm depth by 7°C.The different winter-grown crops or the poultry litter did not affect M. incognita soil population levels. However, root galling on summer tomato was reduced by 36%, and tomato yields increased by 19% after incorporating broccoli compared to the fallow control. This crop also produced the highest amount of biomass of the five winter-grown crops. Over the three-year trial period, poultry litter increased tomato yields, but did not affect root galling caused by M. incognita. We conclude that cultivation followed by soil incorporation of broccoli reduced M. incognita damage to tomato. This effect is possibly due to delaying or preventing a portion of the nematodes to reach the host roots. We also observed that M. incognita populations did not increase under a host crop during the cool season when soil temperatures remained low (< 18°C). PMID:22736848

  8. Snowfall Measurements at a Boreal Forest Site in Saskatchewan/Canada: Contribution to WMO Solid Precipitation Intercomparison Experiment (SPICE)

    NASA Astrophysics Data System (ADS)

    Yang, D.

    2015-12-01

    Snowfall is important to cold region climate and hydrology including Canada. Large uncertainties and biases exist in gauge-measured precipitation datasets and products. These uncertainties affect important decision-making, water resources assessments, climate change analyses, and calibrations of remote sensing algorithms and land surface models. Efforts have been made at both the national and international levels to quantity the errors/biases in precipitation measurements, such as the WMO Solid Precipitation Intercomparison Experiment (WMO-SPICE). As part of Canada's contribution to the WMO SPICE project, a test site has been set up in the southern Canadian Boreal forest to compare the DFIR and bush gauge and test other instruments. Snowfall and meteorological data have been collected over the past 2 winters. This presentation will summarize the results of recent data analyses, evaluate the performance of various gauges for snowfall observations in the northern regions, and discuss future perspectives regarding cold/mountain region precipitation research. The methods and results of this research will improve precipitation measurements and data quality over the cold and mountain regions, directly supporting the WMO SPICE and the MOUNTerrain projects.

  9. Total Ozone Mapping Spectrometer (TOMS) observations of increases in Asian aerosol in winter from 1979 to 2000

    SciTech Connect

    Massie, Steven T.; Torres, O.; Smith, Steven J.

    2004-12-01

    Emission inventories indicate that the largest increases in SO{sub 2} emissions have occurred in Asia during the last 20 years. By inference, largest increases in aerosol, produced primarily by the conversion of SO{sub 2} to sulfate, should have occurred in Asia during the same time period. Decadal changes in regional aerosol optical depths are calculated by analyzing Total Ozone Mapping Spectrometer (TOMS) vertical aerosol optical depths (converted to 550 nm) from 1979 to 2000 on a 1{sup o} by 1{sup o} global grid. The anthropogenic component of the TOMS aerosol record is maximized by examining the seasonal cycles of desert dust and Boreal fire smoke, and identifying the months of the year for which the desert dust and Boreal fire smoke are least conspicuous. Gobi and Taklimakan desert dust in Asia is prevalent in the TOMS record during spring, and eastern Siberian smoke from Boreal forest fires is prevalent during summer. Aerosol trends are calculated on a regional basis during winter (November-February) to maximize the anthropogenic component of the aerosol record. Large increases in aerosol optical depths between 1979 and 2000 are present over the China coastal plain and the Ganges river basin in India. Aerosol increased by 17% per decade during winter over the China coastal plain, while SO{sub 2} emissions over the same geographical region increased by 33% per decade.

  10. The impact of a windshield in a tipping bucket rain gauge on the reduction of losses in precipitation measurements during snowfall events

    NASA Astrophysics Data System (ADS)

    Buisan, Samuel T.; Collado, Jose Luis; Alastrue, Javier

    2016-04-01

    The amount of snow available controls the ecology and hydrological response of mountainous areas and cold regions and affects economic activities including winter tourism, hydropower generation, floods and water supply. An accurate measurement of snowfall accumulation amount is critical and source of error for a better evaluation and verification of numerical weather forecast, hydrological and climate models. It is well known that the undercatch of solid precipitation resulting from wind-induced updrafts at the gauge orifice is the main factor affecting the quality and accuracy of the amount of snowfall precipitation. This effect can be reduced by the use of different windshields. Overall, Tipping Bucket Rain Gauges (TPBRG) provide a large percentage of the precipitation amount measurements, in all climate regimes, estimated at about 80% of the total of observations by automatic instruments. In the frame of the WMO-SPICE project, we compared at the Formigal-Sarrios station (Spanish Pyrenees, 1800 m a.s.l.) the measured precipitation in two heated TPBRGs, one of them protected with a single alter windshield in order to reduce the wind bias. Results were contrasted with measured precipitation using the SPICE reference gauge (Pluvio2 OTT) in a Double Fence Intercomparison Reference (DFIR). Results reported that shielded reduces undercatch up to 40% when wind speed exceeds 6 m/s. The differences when compared with the reference gauge reached values higher than 70%. The inaccuracy of these measurements showed a significant impact in nowcasting operations and climatology in Spain, especially during some heavy snowfall episodes. Also, hydrological models showed a better agreement with the observed rivers flow when including the precipitation not accounted during these snowfall events. The conclusions of this experiment will be used to take decisions on the suitability of the installation of windshields in stations characterized by a large quantity of snowfalls during the

  11. CO2 Emission Increases with Damage Severity in Moso Bamboo Forests Following a Winter Storm in Southern China

    NASA Astrophysics Data System (ADS)

    Liu, Sheng; Xu, Hangmei; Ding, Jiuming; Chen, Han Y. H.; Wang, Jiashe; Xu, Zikun; Ruan, Honghua; Chen, Yuwei

    2016-07-01

    Despite the prevalence of disturbances in forests, the effects of disturbances on soil carbon processes are not fully understood. We examined the influences of a winter storm on soil respiration and labile soil organic carbon (SOC) of a Moso Bamboo (Phyllostachys heterocycle) plantation in the Wuyi Mountains in Southern China from May 2008 to May 2009. We sampled stands that were damaged at heavy, moderate, and light levels, which yielded aboveground biomass inputs to the soil at 22.12 ± 0.73 (mean ± 1 s.e.m.), 10.40 ± 1.09, and 5.95 ± 0.73 Mg per hectare, respectively. We found that soil respiration rate and annual cumulative CO2 emissions were significantly higher in heavily damaged sites than moderately and lightly damaged sites. Soil temperature was the most important environmental factor affecting soil respiration rate across all studied stands. However, soil respiration sensitivity to temperature (Q10) decreased in heavily damaged sites. Microbial biomass carbon and its proportion to total SOC increased with damage intensity. Soil respiration rate was positively correlated to microbial biomass carbon and soil moisture. Our results indicated that the increase of soil respiration following canopy disturbance from winter storm resulted from increased microbial biomass carbon, soil moisture, and temperature.

  12. CO2 Emission Increases with Damage Severity in Moso Bamboo Forests Following a Winter Storm in Southern China.

    PubMed

    Liu, Sheng; Xu, Hangmei; Ding, Jiuming; Chen, Han Y H; Wang, Jiashe; Xu, Zikun; Ruan, Honghua; Chen, Yuwei

    2016-01-01

    Despite the prevalence of disturbances in forests, the effects of disturbances on soil carbon processes are not fully understood. We examined the influences of a winter storm on soil respiration and labile soil organic carbon (SOC) of a Moso Bamboo (Phyllostachys heterocycle) plantation in the Wuyi Mountains in Southern China from May 2008 to May 2009. We sampled stands that were damaged at heavy, moderate, and light levels, which yielded aboveground biomass inputs to the soil at 22.12 ± 0.73 (mean ± 1 s.e.m.), 10.40 ± 1.09, and 5.95 ± 0.73 Mg per hectare, respectively. We found that soil respiration rate and annual cumulative CO2 emissions were significantly higher in heavily damaged sites than moderately and lightly damaged sites. Soil temperature was the most important environmental factor affecting soil respiration rate across all studied stands. However, soil respiration sensitivity to temperature (Q10) decreased in heavily damaged sites. Microbial biomass carbon and its proportion to total SOC increased with damage intensity. Soil respiration rate was positively correlated to microbial biomass carbon and soil moisture. Our results indicated that the increase of soil respiration following canopy disturbance from winter storm resulted from increased microbial biomass carbon, soil moisture, and temperature. PMID:27468803

  13. CO2 Emission Increases with Damage Severity in Moso Bamboo Forests Following a Winter Storm in Southern China

    PubMed Central

    Liu, Sheng; Xu, Hangmei; Ding, Jiuming; Chen, Han Y. H.; Wang, Jiashe; Xu, Zikun; Ruan, Honghua; Chen, Yuwei

    2016-01-01

    Despite the prevalence of disturbances in forests, the effects of disturbances on soil carbon processes are not fully understood. We examined the influences of a winter storm on soil respiration and labile soil organic carbon (SOC) of a Moso Bamboo (Phyllostachys heterocycle) plantation in the Wuyi Mountains in Southern China from May 2008 to May 2009. We sampled stands that were damaged at heavy, moderate, and light levels, which yielded aboveground biomass inputs to the soil at 22.12 ± 0.73 (mean ± 1 s.e.m.), 10.40 ± 1.09, and 5.95 ± 0.73 Mg per hectare, respectively. We found that soil respiration rate and annual cumulative CO2 emissions were significantly higher in heavily damaged sites than moderately and lightly damaged sites. Soil temperature was the most important environmental factor affecting soil respiration rate across all studied stands. However, soil respiration sensitivity to temperature (Q10) decreased in heavily damaged sites. Microbial biomass carbon and its proportion to total SOC increased with damage intensity. Soil respiration rate was positively correlated to microbial biomass carbon and soil moisture. Our results indicated that the increase of soil respiration following canopy disturbance from winter storm resulted from increased microbial biomass carbon, soil moisture, and temperature. PMID:27468803

  14. Social perceptions versus meteorological observations of snow and winter along the Front Range

    NASA Astrophysics Data System (ADS)

    Milligan, William James, IV

    This research aims to increase understanding of Front Range residents' perceptions of snow, winter and hydrologic events. This study also investigates how an individual's characteristics may shape perceptions of winter weather and climate. A survey was administered to determine if perceptions of previous winters align with observed meteorological data. The survey also investigated how individual characteristics influence perceptions of snow and winter weather. The survey was conducted primarily along the Front Range area of the state of Colorado in the United States of America. This is a highly populated semi-arid region that acts as an interface between the agricultural plains to the east that extend to the Mississippi River and the Rocky Mountains to the west. The climate is continental, and while many people recreate in the snowy areas of the mountains, most live where annual snowfall amounts are low. Precipitation, temperature, and wind speed datasets from selected weather stations were analyzed to determine correct survey responses. Survey analysis revealed that perceptions of previous winters do not necessarily align with observed meteorological data. The mean percentage of correct responses to all survey questions was 36.8%. Further analysis revealed that some individual characteristics (e.g. winter recreation, source of winter weather information) did influence correct responses to survey questions.

  15. Long-term continuous monitoring of mercury in the Russian arctic: winter increase of atmospheric mercury depletion events

    NASA Astrophysics Data System (ADS)

    Pankratov, Fidel; Mahura, Alexander; Popov, Valentin; Katz, Oleg

    2014-05-01

    Among pollutants mercury is a major environmental concern due to its ecological hazard. The mercury can reside in the atmosphere for a long time high, and it is a reason of its global propagation in the Northern Hemisphere and elevated mercury concentrations are reported in the Arctic environment. First time, in 1995, the effect of atmospheric mercury depletion in the troposphere was found at the Canadian station Alert. This phenomenon (called the Atmospheric Mercury Depletion Event - AMDE) is observed during April-June, when the Polar sunrise starts till the end of the snowmelt. The same effect was reported for other polar stations situated to the north of 60° N. Long-term continuous monitoring of gaseous elemental mercury in the surface air at the polar station Amderma (69,720N; 61,620E) using the analyzer Tekran 2537A has been conducted from Jun 2001 to date. Individual measurements were collected every thirty minutes. It has been shown, that during eleven years of observations the AMDEs were observed every year, from the end of March till early June. For the winter period (Dec-Feb) these events of the atmospheric mercury depletion were registered from 2010 to 2013, which had not been observed before. A large number of hours during the day, when the concentration of mercury was recorded at level of below 1 ng/m3, was registered during Dec-Feb. The sun declination above the horizon is negative, and solar activity is still not enough to trigger the photochemical reactions. The these last 3 years confirmed a tendency to displacement of AMDEs to the winter season, which leads to an additional factor entry of mercury in various biological objects, due to the additional deposition of various forms of mercury on the snowpack. At the same time, especially during the winter seasons, there is a substantial increase (up to 8 times) of AMDEs, compared with the previous years. In particular, in winter 2013 the maximum number of AMDs reached 31 cases. The explanation can be

  16. How maize monoculture and increasing winter rainfall have brought the hibernating European hamster to the verge of extinction

    NASA Astrophysics Data System (ADS)

    Tissier, Mathilde L.; Handrich, Yves; Robin, Jean-Patrice; Weitten, Mathieu; Pevet, Paul; Kourkgy, Charlotte; Habold, Caroline

    2016-05-01

    Over the last decades, climate change and agricultural intensification have been identified as two major phenomena negatively affecting biodiversity. However, little is known about their effects on the life-history traits of hibernating species living in agro-ecosystems. The European hamster (Cricetus cricetus), once a common rodent on agricultural land, is now on the verge of extinction in France. Despite the implemented measures for its protection, populations are still in sharp decline but the reasons for it remain unclear. To investigate how environmental change has affected this hibernating rodent, we used a data set based on 1468 recordings of hamster body mass at emergence from hibernation from 1937 to 2014. We reveal the adverse effects of increasing winter rainfall and maize monoculture intensification on the body mass of wild hamsters. Given the links that exist between body mass, reproductive success and population dynamics in mammals, these results are of particular importance to understand the decline of this species. In view of the rates of maize monoculture intensification and the predicted increase in winter rainfall, it is of the utmost importance to improve land management in Western Europe to avoid the extinction of this species.

  17. How maize monoculture and increasing winter rainfall have brought the hibernating European hamster to the verge of extinction

    PubMed Central

    Tissier, Mathilde L.; Handrich, Yves; Robin, Jean-Patrice; Weitten, Mathieu; Pevet, Paul; Kourkgy, Charlotte; Habold, Caroline

    2016-01-01

    Over the last decades, climate change and agricultural intensification have been identified as two major phenomena negatively affecting biodiversity. However, little is known about their effects on the life-history traits of hibernating species living in agro-ecosystems. The European hamster (Cricetus cricetus), once a common rodent on agricultural land, is now on the verge of extinction in France. Despite the implemented measures for its protection, populations are still in sharp decline but the reasons for it remain unclear. To investigate how environmental change has affected this hibernating rodent, we used a data set based on 1468 recordings of hamster body mass at emergence from hibernation from 1937 to 2014. We reveal the adverse effects of increasing winter rainfall and maize monoculture intensification on the body mass of wild hamsters. Given the links that exist between body mass, reproductive success and population dynamics in mammals, these results are of particular importance to understand the decline of this species. In view of the rates of maize monoculture intensification and the predicted increase in winter rainfall, it is of the utmost importance to improve land management in Western Europe to avoid the extinction of this species. PMID:27150008

  18. How maize monoculture and increasing winter rainfall have brought the hibernating European hamster to the verge of extinction.

    PubMed

    Tissier, Mathilde L; Handrich, Yves; Robin, Jean-Patrice; Weitten, Mathieu; Pevet, Paul; Kourkgy, Charlotte; Habold, Caroline

    2016-01-01

    Over the last decades, climate change and agricultural intensification have been identified as two major phenomena negatively affecting biodiversity. However, little is known about their effects on the life-history traits of hibernating species living in agro-ecosystems. The European hamster (Cricetus cricetus), once a common rodent on agricultural land, is now on the verge of extinction in France. Despite the implemented measures for its protection, populations are still in sharp decline but the reasons for it remain unclear. To investigate how environmental change has affected this hibernating rodent, we used a data set based on 1468 recordings of hamster body mass at emergence from hibernation from 1937 to 2014. We reveal the adverse effects of increasing winter rainfall and maize monoculture intensification on the body mass of wild hamsters. Given the links that exist between body mass, reproductive success and population dynamics in mammals, these results are of particular importance to understand the decline of this species. In view of the rates of maize monoculture intensification and the predicted increase in winter rainfall, it is of the utmost importance to improve land management in Western Europe to avoid the extinction of this species. PMID:27150008

  19. Estimation and Mapping of the Winter-Time Increase of the Water Ice Amount in the Martian Surface Soil Based on the TES TI Seasonal Variations Analysis

    NASA Astrophysics Data System (ADS)

    Kuzmin, R. O.; Zabalueva, E. V.; Christensen, P. R.

    2008-03-01

    In the work we presents the preliminary results of new method for estimation and global mapping of the winter-time increase of the water ice in the martian surface soil based on the TES TI data analysis.

  20. Numerical simulations of snowfall events: Sensitivity analysis of physical parameterizations

    NASA Astrophysics Data System (ADS)

    Fernández-González, S.; Valero, F.; Sánchez, J. L.; Gascón, E.; López, L.; García-Ortega, E.; Merino, A.

    2015-10-01

    Accurate estimation of snowfall episodes several hours or even days in advance is essential to minimize risks to transport and other human activities. Every year, these episodes cause severe traffic problems on the northwestern Iberian Peninsula. In order to analyze the influence of different parameterization schemes, 15 snowfall days were analyzed with the Weather Research and Forecasting (WRF) model, defining three nested domains with resolutions of 27, 9, and 3 km. We implemented four microphysical parameterizations (WRF Single-Moment 6-class scheme, Goddard, Thompson, and Morrison) and two planetary boundary layer schemes (Yonsei University and Mellor-Yamada-Janjic), yielding eight distinct combinations. To validate model estimates, a network of 97 precipitation gauges was used, together with dichotomous data of snowfall presence/absence from snowplow requests to the emergency service of Spain and observatories of the Spanish Meteorological Agency. The results indicate that the most accurate setting of WRF for the study area was that using the Thompson microphysical parameterization and Mellor-Yamada-Janjic scheme, although the Thompson and Yonsei University combination had greater accuracy in determining the temporal distribution of precipitation over 1 day. Combining the eight deterministic members in an ensemble average improved results considerably. Further, the root mean square difference decreased markedly using a multiple linear regression as postprocessing. In addition, our method was able to provide mean ensemble precipitation and maximum expected precipitation,which can be very useful in the management of water resources. Finally, we developed an application that allows determination of the risk of snowfall above a certain threshold.

  1. Ternary forecast of heavy snowfall in the Honam area, Korea

    NASA Astrophysics Data System (ADS)

    Sohn, Keon Tae; Lee, Jeong Hyeong; Cho, Young Seuk

    2009-03-01

    The objective of this study is to improve the statistical modeling for the ternary forecast of heavy snowfall in the Honam area in Korea. The ternary forecast of heavy snowfall consists of one of three values, 0 for less than 50 mm, 1 for an advisory (50-150 mm), and 2 for a warning (more than 150 mm). For our study, the observed daily snow amounts and the numerical model outputs for 45 synoptic factors at 17 stations in the Honam area during 5 years (2001 to 2005) are used as observations and potential predictors respectively. For statistical modeling and validation, the data set is divided into training data and validation data by cluster analysis. A multi-grade logistic regression model and neural networks are separately applied to generate the probabilities of three categories based on the model output statistic (MOS) method. Two models are estimated by the training data and tested by the validation data. Based on the estimated probabilities, three thresholds are chosen to generate ternary forecasts. The results are summarized in 3×3 contingency tables and the results of the three-grade logistic regression model are compared to those of the neural networks model. According to the model training and model validation results, the estimated three-grade logistic regression model is recommended as a ternary forecast model for heavy snowfall in the Honam area.

  2. Snowfall Characterization by Field Observation and Atmospheric Sounding

    NASA Astrophysics Data System (ADS)

    Francisco, Dianna M.

    The snowfall rate is related to microphysical and dynamical processes in weather systems and is further specified by choice of measurement time, related to the statistics of individual falling ice crystals. A snowflake is definable as a single ice crystal having long range order in the crystal lattice or as a polycrystalline having a multitude of individual single crystals, frozen together as graupel or held together though interlocking shapes as an aggregate snowflake. Snowflakes are collected on a black cloth, next to a scale, and photographed using a macro magnification. Snowflakes captured at the surface are characterized by their appearance from the habit, shape, size, symmetry, thickness, concentration, and fall of the individual ice crystals and of aggregates. Individual ice crystals are identified, counted, and related to the snowfall rate for a calculation of ice crystal number flux. The snowfall rate is characterized as a concentration and an inferred flux of individual nucleation events, to be related to possible direct nucleation and secondary ice formation (such as rime splintering) aloft. Identifying the number of ice crystals requires a degree of persistence and skill, is not readily automated, and is capable of providing key information on the growth history of ice crystals, not obtainable by other means. Surface data is collected through a surface weather station within one mile of the Observation Site. Atmospheric soundings produced by the National Weather Service, less than two miles distance from the Observation Site, aids in the approximation of the ice crystal's life history.

  3. Storage conditions affecting increase in falling number of soft red winter wheat grain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Falling number (FN) of wheat grain, a measure of preharvest sprouting, tends to increase during storage; however, grain and storage conditions that impact FN changes are poorly understood. Wheat grain samples of varying FN from several cultivars were obtained by malting, by incubating wheat stalks,...

  4. Evaluating the Performance of Single and Double Moment Microphysics Schemes During a Synoptic-Scale Snowfall Event

    NASA Technical Reports Server (NTRS)

    Molthan, Andrew L.

    2011-01-01

    Increases in computing resources have allowed for the utilization of high-resolution weather forecast models capable of resolving cloud microphysical and precipitation processes among varying numbers of hydrometeor categories. Several microphysics schemes are currently available within the Weather Research and Forecasting (WRF) model, ranging from single-moment predictions of precipitation content to double-moment predictions that include a prediction of particle number concentrations. Each scheme incorporates several assumptions related to the size distribution, shape, and fall speed relationships of ice crystals in order to simulate cold-cloud processes and resulting precipitation. Field campaign data offer a means of evaluating the assumptions present within each scheme. The Canadian CloudSat/CALIPSO Validation Project (C3VP) represented collaboration among the CloudSat, CALIPSO, and NASA Global Precipitation Measurement mission communities, to observe cold season precipitation processes relevant to forecast model evaluation and the eventual development of satellite retrievals of cloud properties and precipitation rates. During the C3VP campaign, widespread snowfall occurred on 22 January 2007, sampled by aircraft and surface instrumentation that provided particle size distributions, ice water content, and fall speed estimations along with traditional surface measurements of temperature and precipitation. In this study, four single-moment and two double-moment microphysics schemes were utilized to generate hypothetical WRF forecasts of the event, with C3VP data used in evaluation of their varying assumptions. Schemes that incorporate flexibility in size distribution parameters and density assumptions are shown to be preferable to fixed constants, and that a double-moment representation of the snow category may be beneficial when representing the effects of aggregation. These results may guide forecast centers in optimal configurations of their forecast models

  5. Hemispheric and Interannual Comparisons of Polar Winter CO2 Clouds on Mars

    NASA Astrophysics Data System (ADS)

    Hayne, P. O.; Kleinboehl, A.; Heavens, N. G.; Paige, D. A.; Schofield, J. T.; Kass, D. M.; Shirley, J. H.; McCleese, D. J.

    2013-12-01

    Polar carbon dioxide snow clouds contribute substantial material to the seasonal caps of Mars, in addition to direct surface frost formation. Snow clouds also affect the polar heat budget through two primary mechanisms: 1) snow particles decrease polar infrared emissivity during winter, and 2) fine-grained snow deposits increase solar albedo during summer. These effects can strongly alter the seasonal cap mass budget, and possibly explain the existence of the perennial CO2 deposits near the Martian south pole. Mapping the distribution and quantifying the abundance of CO2 snowfall therefore has important implications for the study of Mars' present-day climate. The phenomenon of condensing martian air is of course also interesting in its own right, from an atmospheric science perspective. We used data primarily from the Mars Climate Sounder (MCS) onboard the Mars Reconnaissance Orbiter to investigate the occurrence and properties (optical depth, particle size, altitude) of CO2 clouds in the winter polar regions. MCS retrieved temperature and aerosol opacity profiles now span four Mars years (MY28-MY31), allowing direct inter-annual comparisons for selected locations and seasons. Examples of observed inter-annual variability include decreased snowfall likely due to disruption of the northern polar vortex during the global dust storm of MY28. We also observe very distinct patterns of condensation in the northern and southern hemispheres, with cloud activity being much more intense in the northern hemisphere, but confined to higher latitudes, than in the south. Northern polar winter cloud activity is also distinctly bimodal in time, whereas southern winter cloud activity is evenly distributed over the winter season. In this presentation, we will present a summary of these observations and explore possible explanations for the variability in polar cloud phenomena.

  6. Do CMIP5 models project increase or decrease in Pacific winter cyclone activity under global warming?

    NASA Astrophysics Data System (ADS)

    Chang, E. K.

    2013-12-01

    During the cool season, extratropical cyclones are responsible for much of the high impact weather, including high winds, heavy snow, coastal storm surge, and extreme precipitation events. Thus how cylone activity may change under global warming is of great concern to climate scientists and policy makers alike. With the availability of climate model simulations from multiple modeling centers under Phase 5 of the Coupled Model Intercomparison Project (CMIP5), several recent studies have examined how cyclone activity is projected to change under global warming. While the results of these studies generally agree that the total cyclone frequency is projected to decrease in the Northern Hemisphere, they disagree on how the frequency of deep cyclones may change. One study suggests that the frequency of deep cyclones will increase in the Pacific, while another study concludes that it will decrease significantly throughout the Northern Hemisphere, including over the North Pacific. This study seeks to assess why these two seemingly contradictory conclusions have been made based on CMIP5 data. A single tracking algorithm has been used to derive cyclone statistics from a multiple-model ensemble of 23 CMIP5 simulations based on two different definitions of what cyclones are. One definition treats cyclones as the minima in total sea level pressure (PSL), while the other definition considers cyclones as minima in PSL perturbations -- deviations of PSL from a large scale, low frequency background flow. Results of this study show that when cyclones are defined based on total PSL, the frequency of deep cyclones over the Pacific is projected to increase, while if cyclones are defined as perturbations, the frequency of deep cyclones is projected to decrease. The difference between these two results can be shown to be mainly due to a projected significant deepening of the Aleutian low under global warming. When the CMIP5 projected mean pressure change is added to historical PSL data

  7. Simulations of historical and future trends in snowfall and groundwater recharge for basins draining to Long Island Sound

    USGS Publications Warehouse

    Bjerklie, David M.; Viger, Roland; Trombley, Thomas J.

    2011-01-01

    A regional watershed model was developed for watersheds contributing to Long Island Sound, including the Connecticut River basin. The study region covers approximately 40 900 km2, extending from a moderate coastal climate zone in the south to a mountainous northern New England climate zone dominated by snowmelt in the north. The input data indicate that precipitation and temperature have been increasing for the last 46 years (1961– 2006) across the region. Minimum temperature has increased more than maximum temperature over the same period (1961–2006). The model simulation indicates that there was an upward trend in groundwater recharge across most of the modeled region. However, trends in increasing precipitation and groundwater recharge are not significant at the 0.05 level if the drought of 1961–67 is removed from the time series. The trend in simulated snowfall is not significant across much of the region, although there is a significant downward trend in southeast Connecticut and in central Massachusetts. To simulate future trends, two input datasets, one assuming high carbon emissions and one assuming low carbon emissions, were developed from GCM forecasts. Under both of the carbon emission scenarios, simulations indicate that historical trends will continue, with increases in groundwater recharge over much of the region and substantial snowfall decreases across Massachusetts, Connecticut, southern Vermont, and southern New Hampshire. The increases in groundwater recharge and decreases in snowfall are most pronounced for the high emission scenario.

  8. Physiological traits contributed to the recent increase in yield potential of winter wheat from Henan Province, China.

    PubMed

    Zhou, Bangwei; Sanz-Sáez, Álvaro; Elazab, Abdelhalim; Shen, Tianmin; Sánchez-Bragado, Rut; Bort, Jordi; Serret, Maria Dolors; Araus, José Luis

    2014-05-01

    This experiment aims to test the traits responsible for the increase in yield potential of winter wheat released in Henan Province, China. Seven established cultivars released in the last 20 years and three advanced lines were assayed. The results showed that grain yield was positively correlated with harvest index (HI), kernel number per square meter, and aboveground biomass. In addition, the HI and aboveground biomass showed an increasing trend with the year of release. Therefore, we can conclude that bread wheat breeding advances during recent decades in Henan Province, China, have been achieved through an increase in HI, kernel number per square meter, and aboveground biomass. A higher δ(13)C seems also to be involved in these advances, which suggests a progressive improvement in constitutive water use efficiency not associated with a trend towards lower stomatal conductance in the most recent genotypes. However, genetic advance does not appear related to changes in photosynthesis rates on area basis when measured in the flag leaf or the spike, but only to a higher, whole-spike photosynthesis. Results also indirectly support the concept that under potential yield conditions, the spike contributed more than the flag leaf to kernel formation. PMID:24373600

  9. Universal multifractal analysis of high-resolution snowfall data

    NASA Astrophysics Data System (ADS)

    Raupach, Timothy; Gires, Auguste; Tchiguirinskaia, Ioulia; Schertzer, Daniel; Berne, Alexis

    2016-04-01

    Universal multifractal analysis offers useful insights into the scaling properties of precipitation data. While much work has been done on the scaling properties of rainfall fields, less is known about the scaling properties of solid precipitation such as snowfall, especially at high resolution. We present results of a universal multifractal (UM) analysis of high-resolution solid precipitation data. The data were recorded using a 2D-video-disdrometer (2DVD) situated in the Swiss Alps. Analysis was performed on a one-hour period of snowfall, during which time the mean wind speed was zero, temperatures were low, and no hail was detected. The 2DVD recorded information on individual particles, from which we calculated snow mass. Three "cuts" of the spatio-temporal snowfall process were analysed using the UM framework. First, high-resolution timeseries of precipitation intensity at 100 ms temporal resolution were analysed. These results show two scaling regimes with a transition area between them. Second, we analysed reconstructed vertical columns of particle concentration and snow mass, assuming no horizontal wind and constant vertical velocity (equal to the one recorded on the ground). Strong scaling was observed in the particle concentration fields, with the influence of large (and therefore rare) snowflakes degrading the quality of the scaling observed for higher moments of the particle distribution. There was a clear difference between the measured fields and fields in which the vertical distribution of particles was made homogeneous, indicating that the measured snowfall fields contained non-homogeneous fields. Scaling behaviour was observed down to vertical scales of about 0.5 m, which is similar to published results using rain data. Finally, we used the UM framework to investigate the scaling properties of 2D maps of snow accumulation over a subset of the instrument collection area of 5.12 x 5.12 cm^2. As expected from the vertical column analysis, given that

  10. Increased yield stability of field-grown winter barley (Hordeum vulgare L.) varietal mixtures through ecological processes

    PubMed Central

    Creissen, Henry E.; Jorgensen, Tove H.; Brown, James K.M.

    2016-01-01

    Crop variety mixtures have the potential to increase yield stability in highly variable and unpredictable environments, yet knowledge of the specific mechanisms underlying enhanced yield stability has been limited. Ecological processes in genetically diverse crops were investigated by conducting field trials with winter barley varieties (Hordeum vulgare), grown as monocultures or as three-way mixtures in fungicide treated and untreated plots at three sites. Mixtures achieved yields comparable to the best performing monocultures whilst enhancing yield stability despite being subject to multiple predicted and unpredicted abiotic and biotic stresses including brown rust (Puccinia hordei) and lodging. There was compensation through competitive release because the most competitive variety overyielded in mixtures thereby compensating for less competitive varieties. Facilitation was also identified as an important ecological process within mixtures by reducing lodging. This study indicates that crop varietal mixtures have the capacity to stabilise productivity even when environmental conditions and stresses are not predicted in advance. Varietal mixtures provide a means of increasing crop genetic diversity without the need for extensive breeding efforts. They may confer enhanced resilience to environmental stresses and thus be a desirable component of future cropping systems for sustainable arable farming. PMID:27375312

  11. Intercomparison of snowfall estimates derived from the CloudSat Cloud Profiling Radar and the ground based weather radar network over Sweden

    NASA Astrophysics Data System (ADS)

    Norin, L.; Devasthale, A.; L'Ecuyer, T. S.; Wood, N. B.; Smalley, M.

    2015-08-01

    To be able to estimate snowfall accurately is important for both weather and climate applications. Ground-based weather radars and space-based satellite sensors are often used as viable alternatives to rain-gauges to estimate precipitation in this context. The Cloud Profiling Radar (CPR) onboard CloudSat is especially proving to be a useful tool to map snowfall globally, in part due to its high sensitivity to light precipitation and ability to provide near-global vertical structure. The importance of having snowfall estimates from CloudSat/CPR further increases in the high latitude regions as other ground-based observations become sparse and passive satellite sensors suffer from inherent limitations. Here we intercompared snowfall estimates from two observing systems, CloudSat and Swerad, the Swedish national weather radar network. Swerad offers one of the best calibrated data sets of precipitation amount at very high latitudes that are anchored to rain-gauges and that can be exploited to evaluate usefulness of CloudSat/CPR snowfall estimates in the polar regions. In total 7.2×105 matchups of CloudSat and Swerad over Sweden were inter-compared covering all but summer months (October to May) from 2008 to 2010. The intercomparison shows encouraging agreement between these two observing systems despite their different sensitivities and user applications. The best agreement is observed when CloudSat passes close to a Swerad station (46-82 km), when the observational conditions for both systems are comparable. Larger disagreements outside this range suggest that both platforms have difficulty with shallow snow but for different reasons. The correlation between Swerad and CloudSat degrades with increasing distance from the nearest Swerad station as Swerad's sensitivity decreases as a function of distance and Swerad also tends to overshoots low level precipitating systems further away from the station, leading to underestimation of snowfall rate and occasionally missing

  12. Intercomparison of snowfall estimates derived from the CloudSat Cloud Profiling Radar and the ground-based weather radar network over Sweden

    NASA Astrophysics Data System (ADS)

    Norin, L.; Devasthale, A.; L'Ecuyer, T. S.; Wood, N. B.; Smalley, M.

    2015-12-01

    Accurate snowfall estimates are important for both weather and climate applications. Ground-based weather radars and space-based satellite sensors are often used as viable alternatives to rain gauges to estimate precipitation in this context. In particular, the Cloud Profiling Radar (CPR) on board CloudSat is proving to be a useful tool to map snowfall globally, in part due to its high sensitivity to light precipitation and its ability to provide near-global vertical structure. CloudSat snowfall estimates play a particularly important role in the high-latitude regions as other ground-based observations become sparse and passive satellite sensors suffer from inherent limitations. In this paper, snowfall estimates from two observing systems - Swerad, the Swedish national weather radar network, and CloudSat - are compared. Swerad offers a well-calibrated data set of precipitation rates with high spatial and temporal resolution, at very high latitudes. The measurements are anchored to rain gauges and provide valuable insights into the usefulness of CloudSat CPR's snowfall estimates in the polar regions. In total, 7.2 × 105 matchups of CloudSat and Swerad observations from 2008 through 2010 were intercompared, covering all but the summer months (June to September). The intercomparison shows encouraging agreement between the two observing systems despite their different sensitivities and user applications. The best agreement is observed when CloudSat passes close to a Swerad station (46-82 km), where the observational conditions for both systems are comparable. Larger disagreements outside this range suggest that both platforms have difficulty with shallow snow but for different reasons. The correlation between Swerad and CloudSat degrades with increasing distance from the nearest Swerad station, as Swerad's sensitivity decreases as a function of distance. Swerad also tends to overshoot low-level precipitating systems further away from the station, leading to an

  13. Sensitivity of an energy balance climate model with predicted snowfall rates

    NASA Technical Reports Server (NTRS)

    Bowman, K. P.

    1985-01-01

    A snowfall parameterization and a polar-ice-sheet model are developed and applied to the two-level zonally averaged seasonal energy-balance climate model of Held and Suarez (1979), and sensitivity experiments involving changes in insolation are performed both with and without ice sheets. The results are presented in tables and graphs, and the hydrological-cycle response to insolation changes is found to be similar to that predicted by global-circulation models employing prescribed precipitation levels, with a somewhat higher sensitivity in the snow line. The area covered by ice sheets in the ice-sheet models is shown to be greater than that covered by permanent snow in the models without ice sheets, an effect attributed to lower surface temperatures over the ice. It is inferred that an increase in the solar constant can cause increased high-latitude precipitation but not an ice age.

  14. The social impact of the snowfall of 8 March 2010 in Catalonia

    NASA Astrophysics Data System (ADS)

    Amaro, J.; Llasat, M. C.; Aran, M.

    2010-09-01

    The snowfall of 8 March 2010 affected almost all Catalonia, but especially the northeast where snow thickness was between 20 and 30 cm, locally with higher values up to 60 cm. Strong winds followed the event, exceeding 90 km/h in some places. As a result, infrastructures and public services, also private properties were damaged. Thousands of people were left stranded by the circulatory collapse, suspensions of railway service and by falling branches or trees on road infrastructures blocking accesses to residential areas. The regional government approved funds of 21.4 millions of Euros to mitigate the damage caused by this event, mainly invested in forest cleanup operations and in repairing road damage. The social impact of this event has been so high that 210 news have been published in a newspaper until 23 April, 190 of them during the month of March. From the study of the characteristics of this episode it can be stated that in the coast and pre-costal area, temperature at the same moment of precipitation was between 0ºC and 2ºC and humidity was high. In these zones, the type of precipitation was wet snow. It has to be considered that the combination of wet snow and wind can be a risk because of the ice-weight accumulated on objects (trees, electricity pylons...). As a consequence important damage happened in power network with significant collateral effects and more than 450,000 customers were affected by a power outage during some days. In this study we will compare the consequences of this event with others by means of information published in press. As a result, some set of consequences that are repeated regardless of the magnitude of the phenomenon will be identified. Finally, this event is also an example of the incision of social networks. This snowfall has been classified by mass media as the first "snowfall 2.0": 81600 entrances in Google, 132 Facebook groups and 750 videos made by amateurs in internet. From this study, we will present some reflexions

  15. Exogenous Cytokinins Increase Grain Yield of Winter Wheat Cultivars by Improving Stay-Green Characteristics under Heat Stress

    PubMed Central

    Shi, Yuhua; Cui, Zhengyong; Luo, Yongli; Zheng, Mengjing; Chen, Jin; Li, Yanxia; Yin, Yanping; Wang, Zhenlin

    2016-01-01

    Stay-green, a key trait of wheat, can not only increase the yield of wheat but also its resistance to heat stress during active photosynthesis. Cytokinins are the most potent general coordinator between the stay-green trait and senescence. The objectives of the present study were to identify and assess the effects of cytokinins on the photosynthetic organ and heat resistance in wheat. Two winter wheat cultivars, Wennong 6 (a stay-green cultivar) and Jimai 20 (a control cultivar), were subjected to heat stress treatment from 1 to 5 days after anthesis (DAA). The two cultivars were sprayed daily with 10 mg L-1 of 6-benzylaminopurine (6-BA) between 1 and 3 DAA under ambient and elevated temperature conditions. We found that the heat stress significantly decreased the number of kernels per spike and the grain yield (P < 0.05). Heat stress also decreased the zeatin riboside (ZR) content, but increased the gibberellin (GA3), indole-3-acetic acid (IAA), and abscisic acid (ABA) contents at 3 to 15 DAA. Application of 6-BA significantly (P < 0.05) increased the grain-filling rate, endosperm cell division rate, endosperm cell number, and 1,000-grain weight under heated condition. 6-BA application increased ZR and IAA contents at 3 to 28 DAA, but decreased GA3 and ABA contents. The contents of ZR, ABA, and IAA in kernels were positively and significantly correlated with the grain-filling rate (P < 0.05), whereas GA3 was counter-productive at 3 to 15 DAA. These results suggest that the decrease in grain yield under heat stress was due to a lower ZR content and a higher GA3 content compared to that at elevated temperature during the early development of the kernels, which resulted in less kernel number and lower grain-filling rate. The results also provide essential information for further utilization of the cytokinin substances in the cultivation of heat-resistant wheat. PMID:27203573

  16. Future trends of snowfall days in northern Spain from ENSEMBLES regional climate projections

    NASA Astrophysics Data System (ADS)

    Pons, M. R.; Herrera, S.; Gutiérrez, J. M.

    2015-08-01

    In a previous study Pons et al. (Clim Res 54(3):197-207, 2010. doi: 10.3354/cr01117g) reported a significant decreasing trend of snowfall occurrence in the Northern Iberian Peninsula since the mid 70s. The study was based on observations of annual snowfall frequency (measured as the annual number of snowfall days NSD) from a network of 33 stations ranging from 60 to 1350 m. In the present work we analyze the skill of Regional Climate Models (RCMs) to reproduce this trend for the period 1961-2000 (using both reanalysis- and historical GCM-driven boundary conditions) and the trend and the associated uncertainty of the regional future projections obtained under the A1B scenario for the first half of the twenty-first century. In particular, we consider the regional simulation dataset from the EU-funded ENSEMBLES project, consisting of thirteen state-of-the-art RCMs run at 25 km resolution over Europe. While ERA40 severely underestimates both the mean NSD and its observed trend (-2.2 days/decade), the corresponding RCM simulations driven by the reanalysis appropriately capture the interannual variability and trends of the observed NSD (trends ranging from -3.4 to -0.7, -2.1 days/decade for the ensemble mean). The results driven by the GCM historical runs are quite variable, with trends ranging from -8.5 to 0.2 days/decade (-1.5 days/decade for the ensemble mean), and the greatest uncertainty by far being associated with the particular GCM used. Finally, the trends for the future 2011-2050 A1B runs are more consistent and significant, ranging in this case from -3.7 to -0.5 days/decade (-2.0 days/decade for the ensemble mean), indicating a future significant decreasing trend. These trends are mainly determined by the increasing temperatures, as indicated by the interannual correlation between temperature and NSD (-0.63 in the observations), which is preserved in both ERA40- and GCM-driven simulations.

  17. Future trends of snowfall days in northern Spain from ENSEMBLES regional climate projections

    NASA Astrophysics Data System (ADS)

    Pons, M. R.; Herrera, S.; Gutiérrez, J. M.

    2016-06-01

    In a previous study Pons et al. (Clim Res 54(3):197-207, 2010. doi: 10.3354/cr01117g) reported a significant decreasing trend of snowfall occurrence in the Northern Iberian Peninsula since the mid 70s. The study was based on observations of annual snowfall frequency (measured as the annual number of snowfall days NSD) from a network of 33 stations ranging from 60 to 1350 m. In the present work we analyze the skill of Regional Climate Models (RCMs) to reproduce this trend for the period 1961-2000 (using both reanalysis- and historical GCM-driven boundary conditions) and the trend and the associated uncertainty of the regional future projections obtained under the A1B scenario for the first half of the twenty-first century. In particular, we consider the regional simulation dataset from the EU-funded ENSEMBLES project, consisting of thirteen state-of-the-art RCMs run at 25 km resolution over Europe. While ERA40 severely underestimates both the mean NSD and its observed trend (-2.2 days/decade), the corresponding RCM simulations driven by the reanalysis appropriately capture the interannual variability and trends of the observed NSD (trends ranging from -3.4 to -0.7, -2.1 days/decade for the ensemble mean). The results driven by the GCM historical runs are quite variable, with trends ranging from -8.5 to 0.2 days/decade (-1.5 days/decade for the ensemble mean), and the greatest uncertainty by far being associated with the particular GCM used. Finally, the trends for the future 2011-2050 A1B runs are more consistent and significant, ranging in this case from -3.7 to -0.5 days/decade (-2.0 days/decade for the ensemble mean), indicating a future significant decreasing trend. These trends are mainly determined by the increasing temperatures, as indicated by the interannual correlation between temperature and NSD (-0.63 in the observations), which is preserved in both ERA40- and GCM-driven simulations.

  18. Exploring Alternative Parameterizations for Snowfall with Validation from Satellite and Terrestrial Radars

    NASA Technical Reports Server (NTRS)

    Molthan, Andrew L.; Petersen, Walter A.; Case, Jonathan L.; Dembek, Scott R.

    2009-01-01

    Increases in computational resources have allowed operational forecast centers to pursue experimental, high resolution simulations that resolve the microphysical characteristics of clouds and precipitation. These experiments are motivated by a desire to improve the representation of weather and climate, but will also benefit current and future satellite campaigns, which often use forecast model output to guide the retrieval process. The combination of reliable cloud microphysics and radar reflectivity may constrain radiative transfer models used in satellite simulators during future missions, including EarthCARE and the NASA Global Precipitation Measurement. Aircraft, surface and radar data from the Canadian CloudSat/CALIPSO Validation Project are used to check the validity of size distribution and density characteristics for snowfall simulated by the NASA Goddard six-class, single moment bulk water microphysics scheme, currently available within the Weather Research and Forecast (WRF) Model. Widespread snowfall developed across the region on January 22, 2007, forced by the passing of a mid latitude cyclone, and was observed by the dual-polarimetric, C-band radar King City, Ontario, as well as the NASA 94 GHz CloudSat Cloud Profiling Radar. Combined, these data sets provide key metrics for validating model output: estimates of size distribution parameters fit to the inverse-exponential equations prescribed within the model, bulk density and crystal habit characteristics sampled by the aircraft, and representation of size characteristics as inferred by the radar reflectivity at C- and W-band. Specified constants for distribution intercept and density differ significantly from observations throughout much of the cloud depth. Alternate parameterizations are explored, using column-integrated values of vapor excess to avoid problems encountered with temperature-based parameterizations in an environment where inversions and isothermal layers are present. Simulation of

  19. Exploring Alternate Parameterizations for Snowfall with Validation from Satellite and Terrestrial Radars

    NASA Technical Reports Server (NTRS)

    Molthan, Andrew L.; Petersen, Walter A.; Case, Jonathan L.; Dembek, Scott R.; Jedlovec, Gary J.

    2009-01-01

    Increases in computational resources have allowed operational forecast centers to pursue experimental, high resolution simulations that resolve the microphysical characteristics of clouds and precipitation. These experiments are motivated by a desire to improve the representation of weather and climate, but will also benefit current and future satellite campaigns, which often use forecast model output to guide the retrieval process. Aircraft, surface and radar data from the Canadian CloudSat/CALIPSO Validation Project are used to check the validity of size distribution and density characteristics for snowfall simulated by the NASA Goddard six-class, single-moment bulk water microphysics scheme, currently available within the Weather Research and Forecast (WRF) Model. Widespread snowfall developed across the region on January 22, 2007, forced by the passing of a midlatitude cyclone, and was observed by the dual-polarimetric, C-band radar King City, Ontario, as well as the NASA 94 GHz CloudSat Cloud Profiling Radar. Combined, these data sets provide key metrics for validating model output: estimates of size distribution parameters fit to the inverse-exponential equations prescribed within the model, bulk density and crystal habit characteristics sampled by the aircraft, and representation of size characteristics as inferred by the radar reflectivity at C- and W-band. Specified constants for distribution intercept and density differ significantly from observations throughout much of the cloud depth. Alternate parameterizations are explored, using column-integrated values of vapor excess to avoid problems encountered with temperature-based parameterizations in an environment where inversions and isothermal layers are present. Simulation of CloudSat reflectivity is performed by adopting the discrete-dipole parameterizations and databases provided in literature, and demonstrate an improved capability in simulating radar reflectivity at W-band versus Mie scattering

  20. Snowfall in the Northwest Iberian Peninsula: Synoptic Circulation Patterns and Their Influence on Snow Day Trends

    PubMed Central

    Merino, Andrés; Fernández, Sergio; Hermida, Lucía; López, Laura; Sánchez, José Luis; García-Ortega, Eduardo; Gascón, Estíbaliz

    2014-01-01

    In recent decades, a decrease in snowfall attributed to the effects of global warming (among other causes) has become evident. However, it is reasonable to investigate meteorological causes for such decrease, by analyzing changes in synoptic scale patterns. On the Iberian Peninsula, the Castilla y León region in the northwest consists of a central plateau surrounded by mountain ranges. This creates snowfalls that are considered both an important water resource and a transportation risk. In this work, we develop a classification of synoptic situations that produced important snowfalls at observation stations in the major cities of Castilla y León from 1960 to 2011. We used principal component analysis (PCA) and cluster techniques to define four synoptic patterns conducive to snowfall in the region. Once we confirmed homogeneity of the series and serial correlation of the snowfallday records at the stations from 1960 to 2011, we carried out a Mann-Kendall test. The results show a negative trend at most stations, so there are a decreased number of snowfall days. Finally, variations in these meteorological variables were related to changes in the frequencies of snow events belonging to each synoptic pattern favorable for snowfall production at the observatory locations. PMID:25152912

  1. Modeling changes in extreme snowfall events in the Central Rocky Mountains Region with the Fully-Coupled WRF-Hydro Modeling System

    NASA Astrophysics Data System (ADS)

    gochis, David; rasmussen, Roy; Yu, Wei; Ikeda, Kyoko

    2014-05-01

    Modeling of extreme weather events often require very finely resolved treatment of atmospheric circulation structures in order to produce and localize large magnitudes of moisture fluxes that result in extreme precipitation. This is particularly true for cool season orographic precipitation processes where the representation of landform can significantly influence vertical velocity profiles and cloud moisture entrainment rates. In this work we report on recent progress in high resolution regional climate modeling of the Colorado Headwaters region using an updated version of the Weather Research and Forecasting (WRF) model and a hydrological extension package called WRF-Hydro. Previous work has shown that the WRF-Hydro modeling system forced by high resolution WRF model output can produce credible depictions of winter orographic precipitation and resultant monthly and annual river flows. Here we present results from a detailed study of an extreme springtime snowfall event that occurred along the Colorado Front Range in March of 2003. First an analysis of the simulated streamflows resulting from the melt out of that event are presented followed by an analysis of projected streamflows from the event where the atmospheric forcing in the WRF model is perturbed using the Psuedo-Global-Warming (PGW) perturbation methodology. Results from the impact of warming on total precipitation, snow-rain partitioning and surface hydrological fluxes (evapotranspiration and runoff) will be discussed in the context of how potential changes in temperature impact the amount of precipitation, the phase of precipitation (rain vs. snow) and the timing and amplitude of streamflow responses. It is shown that under the assumptions of the PGW method, intense precipitation rates increase during the event and, more importantly, that more precipitation falls as rain versus snow which significantly amplifies the runoff response from one where runoff is produced gradually to where runoff is more

  2. Sorting out non-sorted circles: Effects of winter climate change on the Collembola community of cryoturbated subarctic tundra

    NASA Astrophysics Data System (ADS)

    Krab, Eveline; Monteux, Sylvain; Becher, Marina; Blume-Werry, Gesche; Keuper, Frida; Klaminder, Jonatan; Kobayashi, Makoto; Lundin, Erik J.; Milbau, Ann; Roennefarth, Jonas; Teuber, Laurenz Michael; Weedon, James; Dorrepaal, Ellen

    2015-04-01

    Non-sorted circles (NSC) are a common type of cryoturbated (frost-disturbed) soil in the arctic and store large amounts of soil organic carbon (SOC) by the burial of organic matter. They appear as sparsely vegetated areas surrounded by denser tundra vegetation, creating patterned ground. Snowfall in the arctic is expected to increase, which will modify freezing intensity and freeze-thaw cycles in soils, thereby impacting on SOC dynamics. Vegetation, soil fauna and microorganisms, important drivers of carbon turnover, may benefit directly from the altered winter conditions and the resulting reduction in cryoturbation, but may also impact each other through trophic cascading. We investigated how Collembola, important decomposer soil fauna in high latitude ecosystems, are affected by increased winter insulation and vegetation cover. We subjected NSC in North-Swedish subarctic alpine tundra to two years of increased thermal insulation (snow fences or fiber cloth) in winter and spring, increasing soil temperatures and strongly reducing freeze-thaw frequency. From these NSC we sampled the Collembola community in: (i) the non-vegetated center, (ii) sparsely vegetated parts in the center and (iii) the vegetated domain surrounding NSC. To link changes in Collembola density and community composition to SOC dynamics, we included measurements of decomposer activity, dissolved organic carbon (DOC) and total extractable nitrogen (TN). We observed differences in Collembola density, community composition and soil fauna activity between the sampling points in the NSC. Specifically Collembola diversity increased with the presence of vegetation and density was higher in the vegetated outer domains. Increased winter insulation did not affect diversity but seemed to negatively affect density and decomposer activity in the vegetated outer domains. Interestingly, SOM distribution over NSC changed with snow addition (also to a lesser extent with fleece insulation) towards less SOM in the

  3. Winters fuels report

    SciTech Connect

    1995-10-27

    The outlook for distillate fuel oil this winter is for increased demand and a return to normal inventory patterns, assuming a resumption of normal, cooler weather than last winter. With industrial production expected to grow slightly from last winter`s pace, overall consumption is projected to increase 3 percent from last winter, to 3.4 million barrels per day during the heating season (October 1, 1995-March 31, 1996). Much of the supply win come from stock drawdowns and refinery production. Estimates for the winter are from the Energy Information Administration`s (EIA) 4th Quarter 1995 Short-Tenn Energy Outlook (STEO) Mid-World Oil Price Case forecast. Inventories in place on September 30, 1995, of 132 million barrels were 9 percent below the unusually high year-earlier level. Inventories of high-sulfur distillate fuel oil, the principal type used for heating, were 13 percent lower than a year earlier. Supply problems are not anticipated because refinery production and the ready availability of imports should be adequate to meet demand. Residential heating off prices are expected to be somewhat higher than last winter`s, as the effects of lower crude oil prices are offset by lower distillate inventories. Heating oil is forecast to average $0.92 per gallon, the highest price since the winter of 1992-93. Diesel fuel (including tax) is predicted to be slightly higher than last year at $1.13 per gallon. This article focuses on the winter assessment for distillate fuel oil, how well last year`s STEO winter outlook compared to actual events, and expectations for the coming winter. Additional analyses include regional low-sulfur and high-sulfur distillate supply, demand, and prices, and recent trends in distillate fuel oil inventories.

  4. Northern-Hemisphere snow cover patterns and formation conditions in winter 2007 and 2012

    NASA Astrophysics Data System (ADS)

    Cui, Hongyan; Qiao, Fangli; Shu, Qi; Yu, Long

    2016-06-01

    The Arctic sea ice minimum records appeared in the Septembers of 2007 and 2012, followed by high snow cover areas in the Northern Hemisphere winters. The snow cover distributions show different spatial patterns in these two years: increased snow cover in Central Asia and Central North America in 2007, while increased snow cover in East Asia and northwestern Europe in 2012. The high snow cover anomaly shifted to higher latitudes in winter of 2012 compared to 2007. It is noticed that the snow cover had positive anomaly in 2007 and 2012 with the following conditions: the negative geopotential height and the related cyclonic wind anomaly were favorable for upwelling, and, with the above conditions, the low troposphere and surface air temperature anomaly and water vapor anomaly were favorable for the formation and maintenance of snowfalls. The negative geopotential height, cyclonic wind and low air temperature conditions were satisfied in different locations in 2007 and 2012, resulting in different spatial snow cover patterns. The cross section of lower air temperature move to higher latitudes in winter of 2012 compared to 2007.

  5. Estrus, ovulation, and serum progesterone, estradiol, and LH concentrations in mares after an increased photoperiod during winter.

    PubMed

    Oxender, W D; Noden, P A; Hafs, H D

    1977-02-01

    On December 11, 1974, 15 seasonally anestrous mares were assigned at random to 1 of 3 experimental groups: outdoor-control, indoor-control, or indoor light-treated (a 16-hour photo-period). This experiment was terminated on April 21, 1975. The five mares in the indoor light-treated group ovulated 59.0+/-6.9 days later, which was 74 days earlier (P less than 0.01) than 2 of the 5 outdoor-controls (the other 3 ovulated after April 21 during a subsequent experiment) and 50 days earlier (P less than 0.05) than the indoor-controls. Durations of the 1st estrus for the 3 groups of mares were 13.3+/-3.6, 8.4+/-2.0, and 6.0+/-1.0 days for the indoor light-treated, indoor-control, and outdoor-control groups, respectively. The indoor light-treated mares averaged 4.2 estrous cycles before April 21, the indoor-control mares averaged 1.4 estrous cycles, and 2 of 5 outdoor-control mares ovulated 1 time during the experiment. The peripheral blood luteinizing hormone (LH), estradiol, and progesterone concentrations were minimal during winter anestrous. The hormone changes normally associated with estrous cycle activity in mares--maximal estradiol and luteinizing hormone concentrations near ovulation and maximal progesterone concentration during diestrus--were observed in all mares beginning at the 1st estrus. Hair loss was observed earlier in the light-treated mares, than in either of the other groups. In conclusion, a 16-hour photo-period initiated in early December for anestrous brood mares caused endocrinologically normal estrous cycles to begin within 2 months. This may allow breeding and foaling considerably earlier than normally expected. PMID:557304

  6. Evaluation of Ground Radar Snowfall Products Using SNOTEL Measurements over Mountainous Regions in Western United States

    NASA Astrophysics Data System (ADS)

    Wen, Y.; Kirstetter, P.; Gourley, J. J.; Hong, Y.; Behrangi, A.

    2015-12-01

    Snow contributes to regional and global water budgets and is of critical importance to our society. Snow can also cause potentially hazardous weather, and rapidly-melting snowpack may cause flooding. For large-scale weather monitoring, snowfall observations from ground radar have become highly desirable. However, verification and refinement of these retrievals requires ground-validation datasets. This study conducts a comprehensive evaluation of NOAA/NSSL Multi-Radar/ Multi-Sensor (MRMS) snowfall products using the Snow Telemetry (SNOTEL) hourly and daily precipitation and Snow Water Equivalent (SWE) datasets. The statistical analysis reveals that the MRMS snowfall estimation has bias compared to SNOTEL in-situ measurements. The bias between MRMS and SNOTEL is studied by considering environmental variables, radar beam sampling characteristics (blockage, beam height and width) and snow density. We expect a step forward towards establishing a robust surface-based snowfall reference database in West Mountainous Region, which can be shared with the satellite snowfall and snowpack community.

  7. An uncertainty model for snowfall rate retrievals from the GPM DPR

    NASA Astrophysics Data System (ADS)

    Nesbitt, S. W.; Reed, K. A.

    2015-12-01

    In this presentation, a simple version of the operational GPM DPR retrieval algorithm will be used to explore uncertainties in snowfall rate retrievals using single-frequency and dual-frequency retrieval methods. This model will be used to quantify uncertainties in retrieval of the profile of snowfall rate within the column as well as at the surface below clutter ranges. The DPR uncertainty model will use data from GPM-GV field campaigns including C3VP (Canadian CloudSat/CALIPSO Validation Programme, conducted in 2007 near Barrie, Ontario, Canada) and GCPEx (Global Precipitation Measurement mission Cold Season Precipitation Experiment, conducted in 2012 near Barrie, Ontario, Canada) to gather a priori microphysical assumptions from surface disdrometer and aircraft data. These assumptions will be used to explore the impact of varying a priori assumptions on measured dual frequency radar profiles observed in snowfall from the ground, aircraft, and spaceborne radars to ascertain sensitivities and key parameters which cause the snowfall rate retrievals to vary in the profile and at the surface. The variability in snowfall parameters the near surface bins within spaceborne radar measurements will also be examined, and suggestions for the treatment of these bins in algorithms will be addressed.

  8. Regional shifts in snowfall, melt in the intermountain west

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-01-01

    The freshwater supplies of the American West rely, for the most part, on snow. The Colorado River, the Rio Grande, and other rivers in the intermountain west—bounded by the Sierra Nevada and Cascade mountains to the west and the Rockies to the east—are the main sources of water for one of the driest parts of the continent, and their flows are predominantly fed by the springtime melt of snow accumulated over the winter. With winter mean temperatures rising in some places by as much as 2.5°C in the past 2 decades, some scientists are concerned that the current hydrological regime of the region could be overthrown, with snow giving way to rain as the dominant form of precipitation. Decreasing snow accumulation and earlier snowmelt onset have been observed in Colorado. Whether these trends extend to the larger intermountain west region, however, is unknown.

  9. Winter Weeds.

    ERIC Educational Resources Information Center

    Lindberg, Lois

    1981-01-01

    Try to learn all you can about a plant in the winter. As the season changes, you can see what the dried seed pod is like in bloom. You are a convert if you notice a spectacular show of summer wildflowers and wonder what sort of winter weed will result. (Author/CM)

  10. Total Lightning Observations within Electrified Snowfall using Polarimetric Radar, LMA, and NLDN Measurements

    NASA Technical Reports Server (NTRS)

    Schultz, Christopher J.; Carey, Lawerence D.; Brunning, Eric C.; Blakeslee, Richard

    2013-01-01

    Four electrified snowfall cases are examined using total lightning measurements from lightning mapping arrays (LMAs), and the National Lightning Detection Network (NLDN) from Huntsville, AL and Washington D.C. In each of these events, electrical activity was in conjunction with heavy snowfall rates, sometimes exceeding 5-8 cm hr-1. A combination of LMA, and NLDN data also indicate that many of these flashes initiated from tall communications towers and traveled over large horizontal distances. During events near Huntsville, AL, the Advanced Radar for Meteorological and Operational Research (ARMOR) C-band polarimetric radar was collecting range height indicators (RHIs) through regions of heavy snowfall. The combination of ARMOR polarimetric radar and VHF LMA observations suggested contiguous layer changes in height between sloping aggregate-dominated layers and horizontally-oriented crystals. These layers may have provided ideal conditions for the development of extensive regions of charge and resultant horizontal propagation of the lightning flashes over large distances.

  11. Nuclear Winter.

    ERIC Educational Resources Information Center

    Ehrlich, Anne

    1984-01-01

    "Nuclear Winter" was recently coined to describe the climatic and biological effects of a nuclear war. These effects are discussed based on models, simulations, scenarios, and projections. Effects on human populations are also considered. (JN)

  12. Effect of storm trajectories on snowfall chemistry in Rocky Mountain National Park, Colorado

    USGS Publications Warehouse

    Ingersoll, G.P.; Tonnessen, K.A.; Campbell, D.H.; Glass, B.R.; Torizzo, A.O.

    2001-01-01

    Snowfall samples from snowstorms lasting 1 to 4 days were collected near the Bear Lake snow telemetry (SnoTel) site in Rocky Mountain National Park, Colorado (ROMO), during the 1998-99 snowfall season to determine if storms moving in from different directions affect the chemistry of precipitation in the park. Storm pathways to Bear Lake during snowfall events were estimated using the HYSPLIT4 backward-trajectory model developed by the National Oceanic and Atmospheric Administration. Deposition of acidic ions of nitrate and sulfate in snowfall during the study varied substantially (two- to threefold) depending on storm trajectory because air masses traversing the park originated from different surrounding areas, including some having large sources of emissions of nitrate and sulfate. Concentrations of nitrate and sulfate in samples were lowest when storms reached ROMO from north and east of the park and were elevated when air masses traveled from the west where a number of power plants are located. Concentrations were highest in storms reaching ROMO from the south, a region with urban areas including Metropolitan Denver.

  13. Relationship between the trajectory of mid-latitude cyclones in the eastern Pacific Ocean and the isotopic composition of snowfall in the Sierra Nevada, California

    NASA Astrophysics Data System (ADS)

    Vasquez, K. T.; Sickman, J. O.; Lucero, D. M.; Heard, A. M.

    2014-12-01

    Climate change has caused a change in the Sierra Nevada snowpack and the timing of its snowmelt, threatening a valuable water resource that provides for 25 million people and 5 million hectares of irrigated land. Understanding past and future variations in the snowpack is crucial in order to plan future water management. Of particular importance would be an archive of the variability of past snowfall, which can be recorded through the isotopic records found in local paleoproxies (e.g., diatoms). We propose to quantify the relationship between sources of atmospheric moisture in the Sierra Nevada and the isotopic composition of its snowpack to uncover whether isotopic variations recorded in paloearchives are a result of the isotopic composition of the precipitation, thereby showing whether these archives could serve as a reliable source of atmospheric moisture. Preliminary analysis conducted from December 2012 to March 2013 at Sequoia National Park resulted in statistically significant correlations between the isotopic composition of the winter snowfall and storm track trajectories. It was observed that storms originating from more northern latitudes had predominantly lighter isotopes (more negative δ 2H and δ18O) and sub-tropical/tropical Pacific storms showed more positive δ 2H and δ18O. This pattern reflects the isotopic gradient of the Pacific Ocean and can prove useful when interpreting the climatic significance of the δ2H and δ18O values in analyzed proxies. While our initial investigation was promising, the winter of 2012 -2013 was abnormally dry compared to long-term averages. Before directing our investigation to known paleoproxies, we aim to determine if the correlation between storm tracks and isotopic composition of precipitation holds in years with average and above average precipitation through analysis of archived samples from calendar years 2007 - 2011 from Giant Forest in Sequoia National Park (southern sierra) and Manzanita Lake in Lassen

  14. Integrating multiple temporal scales of snowfall, soil, and plant processes at the Great Basin Desert - Sierra Nevada ecotone

    NASA Astrophysics Data System (ADS)

    Loik, M. E.

    2012-12-01

    Snowfall is the dominant hydrologic input for high elevations and latitudes of the arid- and semi-arid western United States. Many climate models envision changes in California's Sierra Nevada snow pack characteristics, which would severely impact the storage and release of water for one of the world's largest economies. Climate change threatens the sustainability of this water supply through altered snowfall timing, reduced snowpack depth, changes in snow water equivalents, earlier snowmelt, and highly-uncertain but plausible scenarios of rain-on-snow events. Climate model scenarios envision reduced snow pack and earlier melt under a warmer climate, but how will these changes affect soil and plant water relations and ecosystem processes, such as carbon storage? To address this question, experiments utilize large-scale, long-term snow fences to manipulate snow depth and melt timing at a desert-montane ecotone in eastern California, USA. A combination of instantaneous gas exchange and water potential measurements, plant community surveys, annual ring growth increments, in situ instrumentation, and long-term snow course data were used to couple physical and biological processes at daily, monthly, annual, and decadal scales. At this site, long-term April 1 snow pack depth averages 1344 mm (1928-2011) with a CV of 48%. Snow fences increased equilibrium drift snow depth by 200%. Soil moisture pulses were shorter in duration and lower in magnitude in low- than medium- or high-snowfall years. Evapotranspiration (ET) in this arid location accounted for about 37 mol m-2 d-1 of water loss from the snow pack between January 1 and May 1; sublimation was 10% of ET for the same period. Despite considerable interannual variation in snow depth and total precipitation, plant water potential stayed relatively constant over eight consecutive years, but photosynthesis was highly variable. Over the long-term, changes in snow depth and melt timing have impacted growth of only three

  15. Why does Rhinopithecus bieti prefer the highest elevation range in winter? A test of the sunshine hypothesis.

    PubMed

    Quan, Rui-Chang; Ren, Guopeng; Behm, Jocelyn E; Wang, Lin; Huang, Yong; Long, Yongcheng; Zhu, Jianguo

    2011-01-01

    Environmental factors that affect spatiotemporal distribution patterns of animals usually include resource availability, temperature, and the risk of predation. However, they do not explain the counterintuitive preference of high elevation range in winter by the black-and-white snub-nosed monkey (Rhinopithecus bieti). We asked whether variation of sunshine along with elevations is the key driving force. To test this hypothesis, we conducted field surveys to demonstrate that there was a statistically significant pattern of high elevation use during winter. We then asked whether this pattern can be explained by certain environmental factors, namely temperature, sunshine duration and solar radiation. Finally, we concluded with a possible ecological mechanism for this pattern. In this study, we employed GIS technology to quantify solar radiation and sunshine duration across the monkey's range. Our results showed that: 1) R. bieti used the high altitude range between 4100-4400 m in winter although the yearly home range spanned from 3500-4500 m; 2) both solar radiation and sunshine duration increased with elevation while temperature decreased with elevation; 3) within the winter range, the use of range was significantly correlated with solar radiation and sunshine duration; 4) monkeys moved to the areas with high solar radiation and duration following a snowfall, where the snow melts faster and food is exposed earlier. We concluded that sunshine was the main factor that influences selection of high elevation habitat for R. bieti in winter. Since some other endotherms in the area exhibit similar winter distributional patterns, we developed a sunshine hypothesis to explain this phenomenon. In addition, our work also represented a new method of integrating GIS models into traditional field ecology research to study spatiotemporal distribution pattern of wildlife. We suggest that further theoretical and empirical studies are necessary for better understanding of sunshine

  16. Why Does Rhinopithecus bieti Prefer the Highest Elevation Range in Winter? A Test of the Sunshine Hypothesis

    PubMed Central

    Behm, Jocelyn E.; Wang, Lin; Huang, Yong; Long, Yongcheng; Zhu, Jianguo

    2011-01-01

    Environmental factors that affect spatiotemporal distribution patterns of animals usually include resource availability, temperature, and the risk of predation. However, they do not explain the counterintuitive preference of high elevation range in winter by the black-and-white snub-nosed monkey (Rhinopithecus bieti). We asked whether variation of sunshine along with elevations is the key driving force. To test this hypothesis, we conducted field surveys to demonstrate that there was a statistically significant pattern of high elevation use during winter. We then asked whether this pattern can be explained by certain environmental factors, namely temperature, sunshine duration and solar radiation. Finally, we concluded with a possible ecological mechanism for this pattern. In this study, we employed GIS technology to quantify solar radiation and sunshine duration across the monkey's range. Our results showed that: 1) R. bieti used the high altitude range between 4100–4400 m in winter although the yearly home range spanned from 3500–4500 m; 2) both solar radiation and sunshine duration increased with elevation while temperature decreased with elevation; 3) within the winter range, the use of range was significantly correlated with solar radiation and sunshine duration; 4) monkeys moved to the areas with high solar radiation and duration following a snowfall, where the snow melts faster and food is exposed earlier. We concluded that sunshine was the main factor that influences selection of high elevation habitat for R. bieti in winter. Since some other endotherms in the area exhibit similar winter distributional patterns, we developed a sunshine hypothesis to explain this phenomenon. In addition, our work also represented a new method of integrating GIS models into traditional field ecology research to study spatiotemporal distribution pattern of wildlife. We suggest that further theoretical and empirical studies are necessary for better understanding of sunshine

  17. Investigating the impact of spaceborne radar blind zone on surface snowfall statistics in polar regions

    NASA Astrophysics Data System (ADS)

    Maahn, Maximilian; Burgard, Clara; Crewell, Susanne; Gorodetskaya, Irina; Kneifel, Stefan; Lhermitte, Stef; Van Tricht, Kristof; van Lipzig, Nicole

    2016-04-01

    Currently, global statistics of snowfall are only available from the CloudSat satellite launched in 2006. However, measurements of CloudSat can be only obtained at an altitude of at least 1200 m above ground, because measurements below are contaminated by ground clutter. As a consequence, global estimates of snowfall at the surface have to be estimated from observations at 1200 m above ground. In the presented study, it is investigated how this blind zone impacts snowfall statistics obtained from CloudSat observations in polar regions. For this, 12-months datasets containing observations of a vertically pointing 24 GHz Micro Rain Radar (MRR) are analyzed for three sites: the Belgian Princess Elisabeth station in East-Antarctica, and for Ny-Ålesund as well as Longyearbyen in Svalbard, Norway. Statistical comparison of CloudSat and MRR observations shows that MRRs are suited to study snowfall when reflectivity exceeds -5 dBz. To study the vertical variability of snowfall, MRR radar reflectivity profiles are analyzed with respect to changes in frequency distribution, the number of observed snow events and total precipitation. Results show that the blind zone leads to reflectivity being underestimated by up to 1 dB, the number of events being altered by ±5% and the precipitation amount being underestimated by 9 to 11 percentage points. In order to account for future satellite missions which feature a smaller blind-zone, also the impact of a reduced blind zone of 600 m is analyzed. Even though reducing the blind zone to 600 m leads to better representation of mean reflectivity, it does not improve the bias in event numbers and total precipitation amount.

  18. Winter Games.

    ERIC Educational Resources Information Center

    Tarbuth, Lawson, Comp.

    Educators may find activities for indoor and outdoor winter programs in the games of the traditional Eskimo. These games are dominated by few-step operations and low level structural organization. For the most part they are quickly organized, begun, terminated, and ready to be recommenced. All types of games can be found, including quiet ones,…

  19. Winter Workshop.

    ERIC Educational Resources Information Center

    Council of Outdoor Educators of Quebec, Montreal.

    Materials on 11 topics presented at a winter workshop for Quebec outdoor educators have been compiled into this booklet. Action story, instant replay, shoe factory, sound and action, and find an object to fit the description are described and recommended as group dynamic activities. Directions for five games (Superlative Selection; Data…

  20. Winter Wonderlands

    ERIC Educational Resources Information Center

    Coy, Mary

    2011-01-01

    Listening to people complain about the hardships of winter and the dreariness of the nearly constant gray sky prompted the author to help her sixth graders recognize and appreciate the beauty that surrounds them for nearly five months of the year in western New York. The author opines that if students could see things more artistically, the winter…

  1. Crop water productivity under increasing irrigation capacities in Romania. A spatially-explicit assessment of winter wheat and maize cropping systems in the southern lowlands of the country

    NASA Astrophysics Data System (ADS)

    Dogaru, Diana

    2016-04-01

    Improved water use efficiency in agriculture is a key issue in terms of sustainable management and consumption of water resources in the context of peoples' increasing food demands and preferences, economic growth and agricultural adaptation options to climate variability and change. Crop Water Productivity (CWP), defined as the ratio of yield (or value of harvested crop) to actual evapotranspiration or as the ratio of yield (or value of harvested crop) to volume of supplied irrigation water (Molden et al., 1998), is a useful indicator in the evaluation of water use efficiency and ultimately of cropland management, particularly in the case of regions affected by or prone to drought and where irrigation application is essential for achieving expected productions. The present study investigates the productivity of water in winter wheat and maize cropping systems in the Romanian Plain (49 594 sq. km), an important agricultural region in the southern part of the country which is increasingly affected by drought and dry spells (Sandu and Mateescu, 2014). The scope of the analysis is to assess the gains and losses in CWP for the two crops, by considering increased irrigated cropland and improved fertilization, these being the most common measures potentially and already implemented by the farmers. In order to capture the effects of such measures on agricultural water use, the GIS-based EPIC crop-growth model (GEPIC) (Williams et al., 1989; Liu, 2009) was employed to simulate yields, seasonal evapotranspiration from crops and volume of irrigation water in the Romanian Plain for the 2002 - 2013 interval with focus on 2007 and 2010, two representative years for dry and wet periods, respectively. The GEPIC model operates on a daily time step, while the geospatial input datasets for this analysis (e.g. climate data, soil classes and soil parameters, land use) were harmonized at 1km resolution grid cell. The sources of the spatial data are mainly the national profile agencies

  2. A Physical Model to Determine Snowfall over Land by Microwave Radiometry

    NASA Technical Reports Server (NTRS)

    Skofronick-Jackson, G.; Kim, M.-J.; Weinman, J. A.; Chang, D.-E.

    2003-01-01

    Because microwave brightness temperatures emitted by snow covered surfaces are highly variable, snowfall above such surfaces is difficult to observe using window channels that occur at low frequencies (v less than 100 GHz). Furthermore, at frequencies v less than or equal to 37 GHz, sensitivity to liquid hydrometeors is dominant. These problems are mitigated at high frequencies (v greater than 100 GHz) where water vapor screens the surface emission and sensitivity to frozen hydrometeors is significant. However the scattering effect of snowfall in the atmosphere at those higher frequencies is also impacted by water vapor in the upper atmosphere. This work describes the methodology and results of physically-based retrievals of snow falling over land surfaces. The theory of scattering by randomly oriented dry snow particles at high microwave frequencies appears to be better described by regarding snow as a concatenation of equivalent ice spheres rather than as a sphere with the effective dielectric constant of an air-ice mixture. An equivalent sphere snow scattering model was validated against high frequency attenuation measurements. Satellite-based high frequency observations from an Advanced Microwave Sounding Unit (AMSU-B) instrument during the March 5-6, 2001 New England blizzard were used to retrieve snowfall over land. Vertical distributions of snow, temperature and relative humidity profiles were derived from the Pennsylvania State University-National Center for Atmospheric Research (PSU-NCAR) fifth-generation Mesoscale Model (MM5). Those data were applied and modified in a radiative transfer model that derived brightness temperatures consistent with the AMSU-B observations. The retrieved snowfall distribution was validated with radar reflectivity measurements obtained from the National Oceanic and Atmospheric Administration (NOAA) National Weather Service (NWS) ground-based radar network.

  3. Rapid heat-flowing surveying of geothermal areas, utilizing individual snowfalls as calorimeters

    USGS Publications Warehouse

    White, Donald E.

    1969-01-01

    Local differences in rate of heat transfer in vapor and by conduction through the ground in hot spring areas are difficult and time-consuming to measure quantitatively. Individual heavy snowfalls provide a rapid low-cost means of measuring total heat flow from such ground. After a favorable snowfall (heavy, brief duration, little wind, air temperature near 0°C), contacts between snow-covered and snow-free ground are mapped on a suitable base. Each mapped contact, as time elapses after a specific snowfall, is a heat-flow contour representing a decreasing rate of flow. Calibration of each mapped contact or snow line is made possible by the fact that snow remains on insulated surfaces (such as the boardwalks of Yellowstone's thermal areas) long after it has melted on adjacent warm ground. Heat-flow contours mapped to date range from 450 to 5500 μcal/cm2 sec, or 300 to 3700 times the world average of conductive heat flow. The very high rates of heat flow (2000 to > 10,000 μcal/cm2 sec) are probably too high, and the lower heat flows determinable by the method (2 sec) may be too low. Values indicated by the method are, however, probably within a factor of 2 of the total conductive and convective heat flow. Thermal anomalies from infrared imagery are similar in shape to heat-flow contours of a test area near Old Faithful geyser. Snowfall calorimetry provides a rapid means for evaluating the imagery and computer-derived products of the infrared data in terms of heat flow.

  4. Correcting basin-scale snowfall in a mountainous basin using a distributed snowmelt model and remote-sensing data

    NASA Astrophysics Data System (ADS)

    Shrestha, M.; Wang, L.; Koike, T.; Tsutsui, H.; Xue, Y.; Hirabayashi, Y.

    2014-02-01

    Adequate estimation of the spatial distribution of snowfall is critical in hydrologic modelling. However, this is a well-known problem in estimating basin-scale snowfall, especially in mountainous basins with data scarcity. This study focuses on correction and estimation of this spatial distribution, which considers topographic effects within the basin. A method is proposed that optimises an altitude-based snowfall correction factor (Cfsnow). This is done through multi-objective calibration of a spatially distributed, multilayer energy and water balance-based snowmelt model (WEB-DHM-S) with observed discharge and remotely sensed snow cover data from the Moderate Resolution Imaging Spectroradiometer (MODIS). The Shuffled Complex Evolution-University of Arizona (SCE-UA) automatic search algorithm is used to obtain the optimal value of Cfsnow for minimum cumulative error in discharge and snow cover simulations. Discharge error is quantified by Nash-Sutcliffe efficiency and relative volume deviation, and snow cover error was estimated by pixel-by-pixel analysis. The study region is the heavily snow-fed Yagisawa Basin of the Upper Tone River in northeast Japan. First, the system was applied to one snow season (2002-2003), obtaining an optimised Cfsnow of 0.0007 m-1. For validation purposes, the optimised Cfsnow was implemented to correct snowfall in 2004, 2002 and 2001. Overall, the system was effective, implying improvements in correlation of simulated versus observed discharge and snow cover. The 4 yr mean of basin-average snowfall for the corrected spatial snowfall distribution was 1160 mm (780 mm before correction). Execution of sensitivity runs against other model input and parameters indicated that Cfsnow could be affected by uncertainty in shortwave radiation and setting of the threshold air temperature parameter. Our approach is suitable to correct snowfall and estimate its distribution in poorly gauged basins, where elevation dependence of snowfall amount is

  5. Correcting basin-scale snowfall in a mountainous basin using a distributed snowmelt model and remote sensing data

    NASA Astrophysics Data System (ADS)

    Shrestha, M.; Wang, L.; Koike, T.; Tsutsui, H.; Xue, Y.; Hirabayashi, Y.

    2013-09-01

    Adequate estimation of the spatial distribution of snowfall is critical in hydrologic modeling. However, this is a well-known problem in estimating basin-scale snowfall, especially in mountainous basins with data scarcity. This study focuses on correction and estimation of this spatial distribution, which considers topographic effects within the basin. A method is proposed that optimizes an altitude-based snowfall correction factor (Cfsnow). This is done through multi-objective calibration of a spatially distributed, multilayer energy and water balance-based snowmelt model (WEB-DHM-S) with observed discharge and remotely sensed snow cover data from the Moderate Resolution Imaging Spectroradiometer (MODIS). The Shuffled Complex Evolution - University of Arizona automatic search algorithm is used to obtain the optimal value of Cfsnow for minimum cumulative error in discharge and snow cover simulations. Discharge error is quantified by Nash-Sutcliffe efficiency and relative volume deviation, and snow cover error was estimated by pixel-by-pixel analysis. The study region is the heavily snow-fed Yagisawa Basin of the Upper Tone River in northeast Japan. First, the system was applied to one snow season (2002-2003), obtaining an optimized Cfsnow of 0.0007 m-1. For validation purposes, the optimized Cfsnow was implemented to correct snowfall in 2004, 2002 and 2001. Overall, the system was effective, implying improvements in correlation of simulated vs. observed discharge and snow cover. The 4 yr mean of basin-average snowfall for the corrected spatial snowfall distribution was 1160 mm (780 mm before correction). Execution of sensitivity runs against other model input and parameters indicated that Cfsnow could be affected by uncertainty in shortwave radiation and setting of the threshold air temperature parameter. Our approach is suitable to correct snowfall and estimate its distribution in poorly-gauged basins, where elevation dependence of snowfall amount is strong.

  6. Relationship between the trajectory of mid-latitude cyclones in the eastern Pacific Ocean and the isotopic composition of snowfall in the Sierra Nevada, California

    NASA Astrophysics Data System (ADS)

    Vasquez, K. T.; Sickman, J. O.; Heard, A.; Lucero, D.

    2013-12-01

    Diatoms, preserved in lake sediments, provide a potential archive of snowfall variability in the Sierra Nevada through their sensitivity to changes in water chemistry (a proxy for runoff volume) and by recording the isotopic composition of snow-melt (potentially a proxy for sources of atmospheric moisture). In the Sierra Nevada, we hypothesize that the oxygen isotopic composition of diatom silica is principally controlled by snow and that the isotopic composition of snow varies as a function of the tracks of mid-latitude cyclonic storms in the eastern Pacific Ocean. Snow samples from discrete storms were collected from December 2012 to March 2013 at 2042 meters a.s.l. in Sequoia National Park. The δ18O and δ2H values of the snow samples were measured using a temperature-conversion elemental analyzer coupled to a Delta V isotope ratio mass spectrometer. The isotopic measurements were then coupled to 3, 5 and 7-day air mass back trajectories using the NOAA HYSPLIT model. The measured δ18O values ranged from -17.6 to -7.8 per mil and the δ2H ranged from -119.8 to -73.3 per mil. Both δ18O and δ2H were inversely related to the latitude of the storm origin (R^2 values of 0.67 and 0.57, respectively). Winter storms from the Gulf of Alaska were the most isotopically depleted while storms originating in the subtropical/tropical Pacific were the most isotopically enriched, reflecting the overall latitudinal pattern of ocean-water isotope composition in the Pacific Ocean. Our results suggest that the isotopic composition of Sierra Nevada snowfall is influenced by storm track trajectory and this relationship could be useful in interpreting the climatic significance of δ18O of diatom silica preserved in lake cores.

  7. A Physical Model to Estimate Snowfall over Land using AMSU-B Observations

    NASA Technical Reports Server (NTRS)

    Kim, Min-Jeong; Weinman, J. A.; Olson, W. S.; Chang, D.-E.; Skofronick-Jackson, G.; Wang, J. R.

    2008-01-01

    In this study, we present an improved physical model to retrieve snowfall rate over land using brightness temperature observations from the National Oceanic and Atmospheric Administration's (NOAA) Advanced Microwave Sounder Unit-B (AMSU-B) at 89 GHz, 150 GHz, 183.3 +/- 1 GHz, 183.3 +/- 3 GHz, and 183.3 +/- 7 GHz. The retrieval model is applied to the New England blizzard of March 5, 2001 which deposited about 75 cm of snow over much of Vermont, New Hampshire, and northern New York. In this improved physical model, prior retrieval assumptions about snowflake shape, particle size distributions, environmental conditions, and optimization methodology have been updated. Here, single scattering parameters for snow particles are calculated with the Discrete-Dipole Approximation (DDA) method instead of assuming spherical shapes. Five different snow particle models (hexagonal columns, hexagonal plates, and three different kinds of aggregates) are considered. Snow particle size distributions are assumed to vary with air temperature and to follow aircraft measurements described by previous studies. Brightness temperatures at AMSU-B frequencies for the New England blizzard are calculated using these DDA calculated single scattering parameters and particle size distributions. The vertical profiles of pressure, temperature, relative humidity and hydrometeors are provided by MM5 model simulations. These profiles are treated as the a priori data base in the Bayesian retrieval algorithm. In algorithm applications to the blizzard data, calculated brightness temperatures associated with selected database profiles agree with AMSU-B observations to within about +/- 5 K at all five frequencies. Retrieved snowfall rates compare favorably with the near-concurrent National Weather Service (NWS) radar reflectivity measurements. The relationships between the NWS radar measured reflectivities Z(sub e) and retrieved snowfall rate R for a given snow particle model are derived by a histogram

  8. Deuterium content of snow as an index to winter climate in the Sierra Nevada area

    USGS Publications Warehouse

    Friedman, I.; Smith, G.I.

    1972-01-01

    The winter of 1968-69 produced two to three times the amount of precipitation in the Sierra Nevada area, California and Nevada, as the winter of 1969-70. The deuterium content in snow cores collected at the end of each winter at the same sites, which represents the total snowfall of each interval, shows a depletion in 1968-69 of approximately 20 per mil. The higher snowfall in 1968-69 and the depletion of deuterium can be explained by an uncommonly strong westward flow of cold air over and down the western slopes of the Sierras, which interacted with an eastward flow of moist Pacific air that overrode and mixed with the cold air; this resulted in precipitation that occurred in greater than normal amounts and at a lower than normal temperature. Pluvial periods of the Pleistocene may have had the same shift in air-mass trajectory as the wet 1968-69 year. Snow cores collected in the normal 1970-71 winter have deuterium concentrations that resemble those of the normal 1969-70 winter. Small and nonsystematic differences in samples from these two normal winters are due to variations in climatic character as well as to factors inherent in the sampling sites.

  9. Synoptic variability of extreme snowfall in the St. Elias Mountains, Yukon, Canada

    NASA Astrophysics Data System (ADS)

    Andin, Caroline; Zdanowicz, Christian; Copland, Luke

    2015-04-01

    Glaciers in the Wrangell and St. Elias Mountains (Alaska and Yukon) are presently experiencing some of the highest regional wastage rates worldwide. While the effect of regional temperatures on glacier melt rates in this region has been investigated, comparatively little is known about how synoptic climate variations, for example in the position and strength of the Aleutian Low, modulate snow accumulation on these glaciers. Such information is needed to accurately forecast future wastage rates, glacier-water resource availability, and contributions to sea-level rise. Starting in 2000, automated weather stations (AWS) were established in the central St-Elias Mountains (Yukon) at altitudes ranging from 1190 to 5400 m asl, to collect climatological data in support of glaciological research. These data are the longest continuous year-round observations of surface climate ever obtained from this vast glaciated region. Here we present an analysis of snowfall events in the icefields of the St-Elias Mountains based on a decade-long series of AWS observations of snow accumulation. Specifically, we investigated the synoptic patterns and air mass trajectories associated with the largest snowfall events (> 25 cm/12 hours) that occurred between 2002 and 2012. Nearly 80% of these events occurred during the cold season (October-March), and in 74 % of cases the precipitating air masses originated from the North Pacific south of 50°N. Zonal air mass advection over Alaska, or from the Bering Sea or the Arctic Ocean, was comparatively rare (20%). Somewhat counter-intuitively, dominant surface winds in the St. Elias Mountains during high snowfall events were predominantly easterly, probably due to boundary-layer frictional drag and topographic funneling effects. Composite maps of sea-level pressure and 700 mb winds reveal that intense snowfall events between 2002 and 2012 were associated with synoptic situations characterized by a split, eastwardly-shifted or longitudinally

  10. Can anthropogenic aerosol concentrations effect the snowfall rate?

    NASA Astrophysics Data System (ADS)

    Lohmann, U.; Zhang, J.; Pi, J.

    2003-04-01

    The mesoscale model GESIMA is used to simulate microphysical properties of Arctic clouds and their effect on radiation. Different case studies during the FIRE.ACE/SHEBA project show that GESIMA is able to simulate the cloud boundaries, ice and liquid water content and effective radii in good agreement with observations. For two different aerosol scenarios, the simulation results show that the anthropogenic aerosol can alter microphysical properties of Arctic clouds, and consequently modify surface precipitation. Borys et al. (2000) proposed that anthropogenically-induced decreases in cloud droplet size inhibit the riming process. On the contrary, we find that the accretion of snow crystals with cloud droplets is increased in the polluted cloud due to its higher cloud droplet number concentration. Instead the autoconversion rate of cloud droplets and accretion of drizzle by snow decreases caused by the shut-down of the collision-coalescence process in the polluted cloud. The amount of precipitation reaching the surface as snow depends crucially on the crystal shape. If aggregates are assumed, then a 10-fold increase in aerosol concentration leads to an increase in accumulated snow by 40% after 7 hours of simulation whereas the snow amount decreases by 30% when planar crystals are assumed because of the larger accretion efficiency of snow crystals with cloud droplets in case of aggregates. We will also perform climate model simulations to estimate the importance of this effect globally.

  11. Titan's Emergence from Winter

    NASA Technical Reports Server (NTRS)

    Flasar, F. Michael; Achterberg, Richard; Jennings, Donald; Schinder, Paul

    2011-01-01

    We summarize the changes in Titans thermal structure derived from Cassini CIRS and radio-occultation data during the transition from winter to early spring. Titan's surface, and middle atmosphere show noticeable seasonal change, whereas that in most of the troposphere is mated. This can be understood in terms of the relatively small radiative relaxation time in the middle atmosphere and much larger time scale in the troposphere. The surface exhibits seasonal change because the heat capacity in an annual skin depth is much smaller than that in the lowest scale height of the troposphere. Surface temperatures rise 1 K at raid and high latitudes in the winter northern hemisphere and cool in the southern hemisphere. Changes in in the middle atmosphere are more complicated. Temperatures in the middle stratosphere (approximately 1 mbar) increase by a few kelvin at mid northern latitudes, but those at high latitudes first increase as that region moves out of winter shadow, and then decrease. This probably results from the combined effect of increased solar heating as the suit moves higher in the sky and the decreased adiabatic warming as the sinking motions associated with the cross-equatorial meridional cell weaken. Consistent with this interpretation, the warm temperatures observed higher up at the winter polar stratopause cool significantly.

  12. Crop water productivity under increasing irrigation capacities in Romania. A spatially-explicit assessment of winter wheat and maize cropping systems in the southern lowlands of the country

    NASA Astrophysics Data System (ADS)

    Dogaru, Diana

    2016-04-01

    Improved water use efficiency in agriculture is a key issue in terms of sustainable management and consumption of water resources in the context of peoples' increasing food demands and preferences, economic growth and agricultural adaptation options to climate variability and change. Crop Water Productivity (CWP), defined as the ratio of yield (or value of harvested crop) to actual evapotranspiration or as the ratio of yield (or value of harvested crop) to volume of supplied irrigation water (Molden et al., 1998), is a useful indicator in the evaluation of water use efficiency and ultimately of cropland management, particularly in the case of regions affected by or prone to drought and where irrigation application is essential for achieving expected productions. The present study investigates the productivity of water in winter wheat and maize cropping systems in the Romanian Plain (49 594 sq. km), an important agricultural region in the southern part of the country which is increasingly affected by drought and dry spells (Sandu and Mateescu, 2014). The scope of the analysis is to assess the gains and losses in CWP for the two crops, by considering increased irrigated cropland and improved fertilization, these being the most common measures potentially and already implemented by the farmers. In order to capture the effects of such measures on agricultural water use, the GIS-based EPIC crop-growth model (GEPIC) (Williams et al., 1989; Liu, 2009) was employed to simulate yields, seasonal evapotranspiration from crops and volume of irrigation water in the Romanian Plain for the 2002 - 2013 interval with focus on 2007 and 2010, two representative years for dry and wet periods, respectively. The GEPIC model operates on a daily time step, while the geospatial input datasets for this analysis (e.g. climate data, soil classes and soil parameters, land use) were harmonized at 1km resolution grid cell. The sources of the spatial data are mainly the national profile agencies

  13. Snow and glaciers in the tropics: the importance of snowfall level and snow line altitude in the Peruvian Cordilleras

    NASA Astrophysics Data System (ADS)

    Schauwecker, Simone; Rohrer, Mario; Huggel, Christian; Salzmann, Nadine; Montoya, Nilton; Endries, Jason; Perry, Baker

    2016-04-01

    The snow line altitude, defined as the line separating snow from ice or firn surfaces, is among the most important parameters in the glacier mass and energy balance of tropical glaciers, since it determines net shortwave radiation via surface albedo. Therefore, hydroglaciological models require estimations of the melting layer during precipitation events, as well as parameterisations of the transient snow line. Typically, the height of the melting layer is implemented by simple air temperature extrapolation techniques, using data from nearby meteorological stations and constant lapse rates. Nonetheless, in the Peruvian mountain ranges, stations at the height of glacier tongues (>5000 m asl.) are scarce and the extrapolation techniques must use data from distant and much lower elevated stations, which need prior careful validation. Thus, reliable snowfall level and snow line altitude estimates from multiple data sets are necessary. Here, we assemble and analyse data from multiple sources (remote sensing, in-situ station data, reanalysis data) in order to assess their applicability in estimating both, the melting layer and snow line altitude. We especially focus on the potential of radar bright band data from TRMM and CloudSat satellite data for its use as a proxy for the snow/rain transition height. As expected for tropical regions, the seasonal and regional variability in the snow line altitude is comparatively low. During the course of the dry season, Landsat satellite as well as webcam images show that the transient snow line is generally increasing, interrupted by light snowfall or graupel events with low precipitation amounts and fast decay rates. We show limitations and possibilities of different data sources as well as their applicability to validate temperature extrapolation methods. Further on, we analyse the implications of the relatively low variability in seasonal snow line altitude on local glacier mass balance gradients. We show that the snow line

  14. Future increases in Arctic precipitation linked to local evaporation and sea-ice retreat.

    PubMed

    Bintanja, R; Selten, F M

    2014-05-22

    Precipitation changes projected for the end of the twenty-first century show an increase of more than 50 per cent in the Arctic regions. This marked increase, which is among the highest globally, has previously been attributed primarily to enhanced poleward moisture transport from lower latitudes. Here we use state-of-the-art global climate models to show that the projected increases in Arctic precipitation over the twenty-first century, which peak in late autumn and winter, are instead due mainly to strongly intensified local surface evaporation (maximum in winter), and only to a lesser degree due to enhanced moisture inflow from lower latitudes (maximum in late summer and autumn). Moreover, we show that the enhanced surface evaporation results mainly from retreating winter sea ice, signalling an amplified Arctic hydrological cycle. This demonstrates that increases in Arctic precipitation are firmly linked to Arctic warming and sea-ice decline. As a result, the Arctic mean precipitation sensitivity (4.5 per cent increase per degree of temperature warming) is much larger than the global value (1.6 to 1.9 per cent per kelvin). The associated seasonally varying increase in Arctic precipitation is likely to increase river discharge and snowfall over ice sheets (thereby affecting global sea level), and could even affect global climate through freshening of the Arctic Ocean and subsequent modulations of the Atlantic meridional overturning circulation. PMID:24805239

  15. Effects of Snowfall on the Thickness and Stability of Mars' Seasonal Ice Caps

    NASA Astrophysics Data System (ADS)

    Hayne, P. O.; Paige, D. A.; Aharonson, O.; Schofield, J. T.; Kass, D. M.; Kleinboehl, A.; Heavens, N. G.; Shirley, J. H.; McCleese, D. J.

    2012-12-01

    Seasonal exchange of carbon dioxide between the Martian atmosphere and ice caps is responsible for cyclical variations of ~30% in global atmospheric pressure, as well as for the growth and retreat of the seasonal ice caps. Energy balance and general circulation models have had limited success in reproducing the important aspects of this cycle, largely due to uncertainties in the radiative properties (albedo and emissivity) of the ice caps. Evidence from remote sensing by several different orbital investigations suggests that snowfall consisting primarily of solid CO2 contributes substantial material to the growing seasonal caps, strongly affecting their radiative properties. However, the mass of material deposited as snow, its spatial and temporal variation, and its effect on the energy budget, have all remained uncertain. Using data from the Mars Climate Sounder (MCS), we have quantified and mapped snow cloud formation and surface accumulation based on opacity profiles and calculated infrared cooling rates. We then compared the derived snowfall distribution to seasonal cap thicknesses derived from Mars Orbiter Laser Altimeter (MOLA) "crossover" data. Large variations in the occurrence, thickness, and timing of snow clouds are observed, with the most extensive and persistent clouds observed over the south polar residual cap (SPRC). We find a strong correlation between clouds, "cold spots" (regions of suppressed thermal emission), and seasonal cap thickness. Furthermore, some of these regions of high snow cloud activity also exhibit high solar albedo in the spring and summer. Together, these results suggest that granular deposits of CO2 snow: 1) are thicker (probably due to lower density) on average than "slab ice" formed by direct vapor deposition; 2) reduce energy loss by thermal emission during the polar night; and 3) reduce energy gain by reflecting solar radiation during spring and summer. As the snowiest place on Mars, the SPRC exhibits all of these properties

  16. Do we have to correct winter precipitation for nowcast applications?

    NASA Astrophysics Data System (ADS)

    Helfricht, Kay; Koch, Roland; Olefs, Marc

    2016-04-01

    In mountain regions like the Alps, a significant fraction of the annual precipitation falls as snow. There is an increasing demand for high-quality analysis, nowcast and short-range forecasts of snowfall. Operational services, such as traffic maintenance, real-time flood-warning systems of hydrological services and avalanche warning products, but also hydropower companies and ski resorts need reliable information on precipitation, snow depth and the corresponding snow water equivalent. However, producing accurate precipitation maps in complex terrain using only remote sensing techniques and uncorrected rain gauge data is a difficult task. In cold and windy conditions, conventional rain gauge measurements are prone to large errors when snow passes the rain gauge and sublimation occurs at heated devices. Empirical correction formulas are given by the WMO to compensate the potential undercatch (Goodison, 2008). The project pluSnow aims to combine snow depth measurements and precipitation data to minimize the error of gauge undercatch on the basis of snow depth data from 63 automatic weather stations (TAWES), operated by the Austrian Central Institute for Meteorology and Geodynamics (ZAMG). These TAWES are equipped with SHM30 laser sensors to measure snow depth with high accuracy and temporal resolution of 0.01 m and 10 minutes, respectively. The pluSnow project will contribute to existing research efforts around the globe which focus on improving the precision of solid precipitation measurements. Here we present a first study based on the original TAWES data between 2006 and 2015. The fraction of solid precipitation to total winter precipitation between November and April (NDJFMA) and the potential undercatch of measured precipitation following Goodison (2008) for all TAWES sorted by altitude are analysed. Examples of the TAWES data in the original high temporal resolution of 10 min are given. The two main parameters used for the correction of precipitation

  17. Multisensor Observation and Simulation of Snowfall During the 2003 Wakasa Bay Field Experiment

    NASA Technical Reports Server (NTRS)

    Johnson, Benjamin T.; Petty, Grant W.; Skofronick-Jackson, Gail; Wang, James W.

    2005-01-01

    This research seeks to assess and improve the accuracy of microphysical assumptions used in satellite passive microwave radiative transfer models and retrieval algorithms by exploiting complementary observations from satellite radiometers, such as TRMM/AMSR-E/GPM, and coincident aircraft instruments, such as the next generation precipitation radar (PR-2). We focus in particular on aircraft data obtained during the Wakasa Bay field experiment, Japan 2003, pertaining to surface snowfall events. The observations of vertical profiles of reflectivity and Doppler-derived fall speeds are used in conjunction with the radiometric measurements to identify 1-D profiles of precipitation particle types, sizes, and concentrations that are consistent with the observations.

  18. Evaluation of the updated regional climate model RACMO2.3: summer snowfall impact on the Greenland Ice Sheet

    NASA Astrophysics Data System (ADS)

    Noël, B.; van de Berg, W. J.; van Meijgaard, E.; Kuipers Munneke, P.; van de Wal, R. S. W.; van den Broeke, M. R.

    2015-09-01

    We discuss Greenland Ice Sheet (GrIS) surface mass balance (SMB) differences between the updated polar version of the RACMO climate model (RACMO2.3) and the previous version (RACMO2.1). Among other revisions, the updated model includes an adjusted rainfall-to-snowfall conversion that produces exclusively snowfall under freezing conditions; this especially favours snowfall in summer. Summer snowfall in the ablation zone of the GrIS has a pronounced effect on melt rates, affecting modelled GrIS SMB in two ways. By covering relatively dark ice with highly reflective fresh snow, these summer snowfalls have the potential to locally reduce melt rates in the ablation zone of the GrIS through the snow-albedo-melt feedback. At larger scales, SMB changes are driven by differences in orographic precipitation following a shift in large-scale circulation, in combination with enhanced moisture to precipitation conversion for warm to moderately cold conditions. A detailed comparison of model output with observations from automatic weather stations, ice cores and ablation stakes shows that the model update generally improves the simulated SMB-elevation gradient as well as the representation of the surface energy balance, although significant biases remain.

  19. Accounting for anthropic energy flux of traffic in winter urban road surface temperature simulations with the TEB model

    NASA Astrophysics Data System (ADS)

    Khalifa, A.; Marchetti, M.; Bouilloud, L.; Martin, E.; Bues, M.; Chancibaut, K.

    2016-02-01

    Snowfall forecasts help winter maintenance of road networks, ensure better coordination between services, cost control, and a reduction in environmental impacts caused by an inappropriate use of de-icers. In order to determine the possible accumulation of snow on pavements, forecasting the road surface temperature (RST) is mandatory. Weather outstations are used along these networks to identify changes in pavement status, and to make forecasts by analyzing the data they provide. Physical numerical models provide such forecasts, and require an accurate description of the infrastructure along with meteorological parameters. The objective of this study was to build a reliable urban RST forecast with a detailed integration of traffic in the Town Energy Balance (TEB) numerical model for winter maintenance. The study first consisted in generating a physical and consistent description of traffic in the model with two approaches to evaluate traffic incidence on RST. Experiments were then conducted to measure the effect of traffic on RST increase with respect to non-circulated areas. These field data were then used for comparison with the forecast provided by this traffic-implemented TEB version.

  20. Accounting for anthropic energy flux of traffic in winter urban road surface temperature simulations with TEB model

    NASA Astrophysics Data System (ADS)

    Khalifa, A.; Marchetti, M.; Bouilloud, L.; Martin, E.; Bues, M.; Chancibaut, K.

    2015-06-01

    A forecast of the snowfall helps winter coordination operating services, reducing the cost of the maintenance actions, and the environmental impacts caused by an inappropriate use of de-icing. In order to determine the possible accumulation of snow on pavement, the forecast of the road surface temperature (RST) is mandatory. Physical numerical models provide such forecast, and do need an accurate description of the infrastructure along with meteorological parameters. The objective of this study was to build a reliable urban RST forecast with a detailed integration of traffic in the Town Energy Balance (TEB) numerical model for winter maintenance. The study first consisted in generating a physical and consistent description of traffic in the model with all the energy interactions, with two approaches to evaluate the traffic incidence on RST. Experiments were then conducted to measure the traffic effect on RST increase with respect to non circulated areas. These field data were then used for comparison with forecast provided by this traffic-implemented TEB version.

  1. Winter range arrival and departure of white-tailed deer in northeastern Minnesota

    USGS Publications Warehouse

    Nelson, M.E.

    1995-01-01

    I analyzed 364 spring and 239 fall migrations by 194 white-tailed deer (Odocoileus virginianus) from 1975 to 1993 in northeastern Minnesota to determine the proximate cause of arrivals on and departures from winter ranges. The first autumn temperatures below -7?C initiated fall migrations for 14% (95% confidence interval (CI) = 0-30) of female deer prior to snowfall in three autumns, but only 2% remained on winter ranges. During 14 autumns, the first temperatures below -7?C coincidental with snowfalls elicited migration in 45% (95% CI = 34-57) of females, and 91 % remained on winter ranges. Arrival dates failed to correlate with independent variables of temperature and snow depth, precluding predictive modeling of arrival on winter ranges. During 13 years, a mean of 80% of females permanently arrived on winter ranges by 31 December. Mean departure dates from winter ranges varied annually (19 March - 4 May) and between winter ranges (14 days) and according to snow depth (15-cm differences). Only 15 - 41 % of deer departed when snow depths were> 30 cm but 80% had done so by the time of lO-cm depths. Mean weekly snow depths in March (18-85 cm) and mean temperature in April (0.3 -8.1 ?c) explained most of the variation in mean departure dates from two winter ranges (Ely, R2 = 0.87, P < 0.0005, n = 19 springs; Isabella, R2 = 0.85, P = 0.0001, n = 12 springs). Mean differences between observed mean departure dates and mean departure dates predicted from equations ranged from 3 days (predictions within the study area) to 8 days (predictions for winter ranges 100-440 km distant).

  2. How does the spaceborne radar blind zone affect derived surface snowfall statistics in polar regions?

    NASA Astrophysics Data System (ADS)

    Maahn, Maximilian; Burgard, Clara; Crewell, Susanne; Gorodetskaya, Irina V.; Kneifel, Stefan; Lhermitte, Stef; Van Tricht, Kristof; Lipzig, Nicole P. M.

    2014-12-01

    Global statistics of snowfall are currently only available from the CloudSat satellite. But CloudSat cannot provide observations of clouds and precipitation within the so-called blind zone, which is caused by ground-clutter contamination of the CloudSat radar and covers the last 1200 m above land/ice surface. In this study, the impact of the blind zone of CloudSat on derived snowfall statistics in polar regions is investigated by analyzing three 12 month data sets recorded by ground-based Micro Rain Radar (MRR) at the Belgian Princess Elisabeth station in East Antarctica and at Ny-Ålesund and Longyearbyen in Svalbard, Norway. MRR radar reflectivity profiles are investigated in respect to vertical variability in the frequency distribution, changes in the number of observed snow events, and impacts on total precipitation. Results show that the blind zone leads to reflectivity being underestimated by up to 1 dB, the number of events being altered by ±5% and the precipitation amount being underestimated by 9 to 11 percentage points. Besides investigating a blind zone of 1200 m, the impacts of a reduced blind zone of 600 m are also analyzed. This analysis will help in assessing future missions with a smaller blind zone. The reduced blind zone leads to improved representation of mean reflectivity but does not improve the bias in event numbers and precipitation amount.

  3. Highway deicing salt dynamic runoff to surface water and subsequent infiltration to groundwater during severe UK winters.

    PubMed

    Rivett, Michael O; Cuthbert, Mark O; Gamble, Richard; Connon, Lucy E; Pearson, Andrew; Shepley, Martin G; Davis, John

    2016-09-15

    Dynamic impact to the water environment of deicing salt application at a major highway (motorway) interchange in the UK is quantitatively evaluated for two recent severe UK winters. The contaminant transport pathway studied allowed controls on dynamic highway runoff and storm-sewer discharge to a receiving stream and its subsequent leakage to an underlying sandstone aquifer, including possible contribution to long-term chloride increases in supply wells, to be evaluated. Logged stream electrical-conductivity (EC) to estimate chloride concentrations, stream flow, climate and motorway salt application data were used to assess salt fate. Stream loading was responsive to salt applications and climate variability influencing salt release. Chloride (via EC) was predicted to exceed the stream Environmental Quality Standard (250mg/l) for 33% and 18% of the two winters. Maximum stream concentrations (3500mg/l, 15% sea water salinity) were ascribed to salt-induced melting and drainage of highway snowfall without dilution from, still frozen, catchment water. Salt persistance on the highway under dry-cold conditions was inferred from stream observations of delayed salt removal. Streambed and stream-loss data demonstrated chloride infiltration could occur to the underlying aquifer with mild and severe winter stream leakage estimated to account for 21 to 54% respectively of the 70t of increased chloride (over baseline) annually abstracted by supply wells. Deicing salt infiltration lateral to the highway alongside other urban/natural sources were inferred to contribute the shortfall. Challenges in quantifying chloride mass/fluxes (flow gauge accuracy at high flows, salt loading from other roads, weaker chloride-EC correlation at low concentrations), may be largely overcome by modest investment in enhanced data acquisition or minor approach modification. The increased understanding of deicing salt dynamic loading to the water environment obtained is relevant to improved

  4. Monitoring a convective winter episode of the Iberian Peninsula using a multichannel microwave radiometer

    NASA Astrophysics Data System (ADS)

    Gascón, E.; Sánchez, J. L.; Fernández-González, S.; Hermida, L.; López, L.; García-Ortega, E.; Merino, A.

    2015-02-01

    On 4 March 2011, a heavy snowfall episode affected the central Iberian Peninsula. Under the TECOAGUA Project (aimed at the study of winter cloud masses that produce snow in the Guadarrama Mountains near Madrid), measurements using a ground-based multichannel microwave radiometer (MMWR) with vertical range 10 km recorded this episode of winter convection embedded within stratiform precipitation. In contrast to radiosondes, data retrieval from the MMWR has a clear advantage for identifying hazardous weather phenomena of short duration, such as winter convective episodes. From these continuous measurements, we analyzed the behavior of variables such as temperature, surface pressure, relative humidity, liquid water content, liquid water path, water vapor content, and integrated water vapor throughout the day. The continuous measurements also permitted construction of skew-T log-P profiles every 15 min during the convective episode, indicating vertical evolution of an event with an appearance similar to a "zipper" in which temperature and dew point temperature profiles are "closed" from the surface to 400 hPa and "reopen" at the end of the event. Finally, we selected six indices of stability most suitable for the study of winter convection, namely, the Showalter index, low-topped convection index, most unstable lifted index, most unstable convective available potential energy (MUCAPE), convective inhibition, and MUCAPE level of free convection. Each of these indices has been evaluated for their capacity to warn of meteorological conditions leading to a convective heavy snowfall event.

  5. Worrying about weird winters

    PubMed Central

    Sinclair, Brent

    2014-01-01

    Winter is a key determinant of biological processes in temperate, alpine, and polar environments. Winters are changing, yet we currently lack the knowledge to adequately predict the impacts of climate change on winter biology, or to link winter conditions to the growing-season performance of most organisms.

  6. Use of Multiple-Angle Snow Camera (MASC) Observations as a Constraint on Radar-Based Retrievals of Snowfall Rate

    NASA Astrophysics Data System (ADS)

    Cooper, S.; Garrett, T. J.; Wood, N.; L'Ecuyer, T. S.

    2015-12-01

    We use a combination of Ka-band Zenith Radar (KaZR) and Multiple-Angle Snow Camera (MASC) observations at the ARM North Slope Alaska Climate Facility Site at Barrow to quantify snowfall. The optimal-estimation framework is used to combine information from the KaZR and MASC into a common retrieval scheme, where retrieved estimates of snowfall are compared to observations at a nearby NWS measurement site for evaluation. Modified from the operational CloudSat algorithm, the retrieval scheme returns estimates of the vertical profile of exponential PSD slope parameter with a constant number density. These values, in turn, can be used to calculate surface snowrate (liquid equivalent) given knowledge of snowflake microphysical properties and fallspeeds. We exploit scattering models for a variety of ice crystal shapes including aggregates developed specifically from observations of snowfall properties at high-latitudes, as well as more pristine crystal shapes involving sector plates, bullet rosettes, and hexagonal columns. As expected, initial retrievals suggest large differences (300% for some events) in estimated snowfall accumulations given the use of the different ice crystal assumptions. The complex problem of how we can more quantitatively link MASC snowflake images to specific radar scattering properties is an ongoing line of research. Here, however, we do quantify the use of MASC observations of fallspeed and PSD parameters as constraint on our optimal-estimation retrieval approach. In terms of fallspeed, we find differences in estimated snowfall of nearly 50% arising from the use of MASC observed fallspeeds relative to those derived from traditional fallspeed parameterizations. In terms of snowflake PSD, we find differences of nearly 25% arising from the use of MASC observed slope parameters relative to those derived from field campaign observations of high-altitude snow events. Of course, these different sources of error conspire to make the estimate of snowfall

  7. Introducing winter canola to the winter wheat-fallow region of the Pacific Northwest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Growers in the low-rainfall, winter wheat-fallow region of the Pacific Northwest are in need of an alternative crop to diversify their markets, manage pests, and increase wheat yields. Winter canola may be a viable crop option for growers in the region. However, agronomic research for winter canol...

  8. River chloride trends in snow-affected urban watersheds: increasing concentrations outpace urban growth rate and are common among all seasons.

    PubMed

    Corsi, Steven R; De Cicco, Laura A; Lutz, Michelle A; Hirsch, Robert M

    2015-03-01

    Chloride concentrations in northern U.S. included in this study have increased substantially over time with average concentrations approximately doubling from 1990 to 2011, outpacing the rate of urbanization in the northern U.S. Historical data were examined for 30 monitoring sites on 19 streams that had chloride concentration and flow records of 18 to 49 years. Chloride concentrations in most studied streams increased in all seasons (13 of 19 in all seasons; 16 of 19 during winter); maximum concentrations occurred during winter. Increasing concentrations during non-deicing periods suggest that chloride was stored in hydrologic reservoirs, such as the shallow groundwater system, during the winter and slowly released in baseflow throughout the year. Streamflow dependency was also observed with chloride concentrations increasing as streamflow decreased, a result of dilution during rainfall- and snowmelt-induced high-flow periods. The influence of chloride on aquatic life increased with time; 29% of sites studied exceeded the concentration for the USEPA chronic water quality criteria of 230 mg/L by an average of more than 100 individual days per year during 2006-2011. The rapid rate of chloride concentration increase in these streams is likely due to a combination of possible increased road salt application rates, increased baseline concentrations, and greater snowfall in the Midwestern U.S. during the latter portion of the study period. PMID:25514764

  9. Effects of volcanic eruption and global warming on snowfall patterns in the Pacific Northwest: Survey of climate data from 36 stations

    SciTech Connect

    Chatelain, E.E.

    1996-09-01

    Patterns in short term annual snowfall totals and long term glacial mass-balance of glaciers in the Pacific Northwest are affected by episodic global volcanic eruptions and the cyclic appearances of the El Nino oceanic current. A comprehensive analysis of climatic data such as snowfall, snow depth, maximum and minimum temperatures, and total precipitation was undertaken for 18 stations in Oregon and Washington between 1948-1995, and for snow-water data from 18 other stations from 1980-1995. These data were also compared to demonstrate regional variations within a given year. Snowfall maxima and Temperature minima recorded in this period closely followed major volcanic events, whereas Snowfall minima and Temperature maxima recorded in the same period coincided with periodic El Nino patterns. Snowfall totals in El Nino years were uniformly sparse region wide, whereas snowfall patterns in other years displayed some regional variation. Of special interest is the cross-correlation of snow-water and snowfall depth/totals data for the period 1980-1995, which records the patterns before and after the eruptions of Mt. Pinatubo (1991-92).

  10. Lessons from the unusual impacts of an abnormal winter in the USA

    NASA Astrophysics Data System (ADS)

    Changnon, Stanley A.; Changnon, David

    2005-09-01

    Economic impacts from the near record warm and snow-free winter of 2001 2 in the United States were assessed to ascertain their dimensions and relevance to issues like climate prediction and climate change. Unusual impacts resulted and embraced numerous sectors (heating/energy use, construction, tourism, insurance, government, and retail sales). Many outcomes were gains/benefits totalling 19.6 billion, with losses of 8.2 billion. Some economists identified the sizable positive impacts as a factor in the nation's recovery from an on-going recession stemming from the terrorist attacks on 11 September 2001. Understanding the impacts of such a winter reveals how climate predictions of such conditions could have great utility in minimising the losses and maximising the gains. The results also have relevance to the global warming issue since most climate models project future average winter temperature and snowfall conditions in the United States to be similar to those experienced in 2001 2.

  11. Winter Weather Emergencies

    MedlinePlus

    Severe winter weather can lead to health and safety challenges. You may have to cope with Cold related health problems, including ... there are no guarantees of safety during winter weather emergencies, you can take actions to protect yourself. ...

  12. The Impacts of Changes in Snowfall on Soil Greenhouse Gas Emissions Using an Automated Chamber System

    NASA Astrophysics Data System (ADS)

    Ruan, L.; Kahmark, K.; Robertson, G.

    2012-12-01

    Snow cover has decreased in many regions of the northern hemisphere and is projected to decrease further in most. The reduced snow cover may enhance soil freezing and increase the depth of frost. The frequency of freeze-thaw cycles is likely to increase due to the reduction of snowpack thickness. Freeze and thaw cycles can strongly affect soil C and N dynamics. The pulses of N2O and CO2 emissions from soil after thawing have been reported in various studies. However, most studies were based on the controlled laboratory conditions or low resolution static chamber methods in situ. Near-continuous automated chambers provide the temporal resolution needed for capturing short-lived pulses of greenhouse gases after intermittent melting events. We investigated the winter and spring response of soil greenhouse gas emissions (CO2, CH4 and N2O) to changes of snow depth using an automated chamber system. This study was established in 2010 at the Kellogg Biological Station (KBS) in southwest Michigan. The plot was no till rotational (corn-soybean-wheat) cropland, most recently in corn. The experiment was a completely randomized design (CRD) with three levels of snow depth: ambient, double, and no snow. Each level had four replicates. Twelve automated chambers were randomly assigned to treatments and greenhouse gas fluxes measured 4 times per day in each plot. There were more freeze-thaw cycles in the no snow treatment than in the ambient and double snow treatments. Soil temperature at 5 cm depth was more variable in the no snow treatment than in the ambient and double snow treatments. CH4 fluxes were uniformly low with no significant difference across three treatments. CO2 showed expected seasonal changes with the highest emission in spring and lowest emissions through the winter. N2O peaks were higher in spring due to freeze thaw effects and cumulative N2O fluxes were substantially higher in the no snow treatment than in the ambient and double snow treatments.

  13. Snowfall measurements using a combination of high spectral resolution lidar and radar observations

    NASA Astrophysics Data System (ADS)

    Eloranta, E.

    2009-04-01

    Aerodynamic flow around gauges and the horizontal transport of windblown snow along the surface produce errors in snowfall measurements. Comparisons between various snow gauges with and without wind shields show as much as as a factor of two difference between measurements(Yang et al., 1999). These problems are particularly significant in the high Arctic where snowfall amount are very low and blowing snow is frequent. This paper describes a lidar-radar based technique to measure the downward flux of snow at an altitude of ~100m. When particles are small compared to the wavelength, radar reflectivity is proportional to the number of snowflakes times the square of the mass of the average snowflake. For particles large compared to the wavelength, the lidar extinction cross section is equal to two times the number of snowflakes times the projected average area of the snowflakes. Donovan and Lammeren(2001) show that the ratio of radar to lidar cross sections can be used to define an effective-diameter-prime, which is proportional to the fourth root of the average mass-squared over the average projected area of the snowflakes. If one assumes a crystal shape this can be converted into an effective-diameter which is the average mass over the average area of the flakes. Multiplying the lidar measured projected area times the effective-diameter yields the mass of the particles. The product of this mass and the radar measured vertical velocity then provides the vertical flux of water. In past work we have tested this measurement approach with data acquired in the high Arctic at Eureka, Canada(80 N,90W). Measurements from the University of Wisconsin High Spectral Resolution Lidar and the NOAA 35 GHz cloud radar were used to compute the time-integrated flux of water at 100 m above the surface. This result was compared with Nipper gauge measurements of snowfall acquired as part of the Eureka weather station record. Best agreement was achieved when the crystals where assumed to

  14. Model and observational analysis of the Northeast's regional winter climate and its relationship to the PNA pattern

    NASA Astrophysics Data System (ADS)

    Notaro, Michael

    A study was performed of the winter climate in the Northeast United States and its relationship to the large-scale circulation. Temperature, radiation, precipitation, and circulation features of the La Nina winter of 1998--1999 were analyzed through observations, NCEP-NCAR Reanalysis, and model simulations by SUNYA regional climate model (RCM). The relationship between the Pacific North American (PNA) pattern and regional winter climate of the Northeast was also investigated. Ten Decembers during the 1980s and 1990s were simulated, five with the most positive and five with the most negative PNA index. RCM reproduced the key climate features of the Northeast during the winter of 1998--1999. The model's circulation closely agreed with the reanalysis, particularly in the mid- and upper-troposphere, and with surface wind observations. Spatial and temporal patterns of temperature and precipitation agreed well with observations, despite a cold bias in the boundary layer (2--3°C) and dry bias in precipitation. The use of six-hourly, rather than twelve-hourly, reanalysis boundary conditions improved the diurnal cycle and increased the success at capturing fast-moving systems, such as fronts, and reproducing hourly weather variations. The relationship of the PNA pattern, and other teleconnection patterns, to the Northeast winter climate was investigated. Positive PNA pattern was associated with a stronger, southeastward shifted jet and colder, drier conditions in the Northeast, while mild surface southerlies were more frequent with negative PNA pattern. In the positive PNA simulations, there was a large air-water thermal gradient over the Great Lakes, enhancing evaporation and fluxes of sensible and latent heat. Precipitation and clouds during positive PNA pattern were less abundant across the domain, although lake-effect maxima were well defined. The PDO (Pacific Decadal Oscillation), PNA, and ENSO (El Nino/Southern Oscillation) teleconnections significantly influenced

  15. Comparing Aircraft Observations of Snowfall to Forecasts Using Single or Two Moment Bulk Water Microphysics Schemes

    NASA Technical Reports Server (NTRS)

    Molthan, Andrew L.

    2010-01-01

    High resolution weather forecast models with explicit prediction of hydrometeor type, size distribution, and fall speed may be useful in the development of precipitation retrievals, by providing representative characteristics of frozen hydrometeors. Several single or double-moment microphysics schemes are currently available within the Weather Research and Forecasting (WRF) model, allowing for the prediction of up to three ice species. Each scheme incorporates different assumptions regarding the characteristics of their ice classes, particularly in terms of size distribution, density, and fall speed. In addition to the prediction of hydrometeor content, these schemes must accurately represent the vertical profile of water vapor to account for possible attenuation, along with the size distribution, density, and shape characteristics of ice crystals that are relevant to microwave scattering. An evaluation of a particular scheme requires the availability of field campaign measurements. The Canadian CloudSat/CALIPSO Validation Project (C3VP) obtained measurements of ice crystal shapes, size distributions, fall speeds, and precipitation during several intensive observation periods. In this study, C3VP observations obtained during the 22 January 2007 synoptic-scale snowfall event are compared against WRF model output, based upon forecasts using four single-moment and two double-moment schemes available as of version 3.1. Schemes are compared against aircraft observations by examining differences in size distribution, density, and content. In addition to direct measurements from aircraft probes, simulated precipitation can also be converted to equivalent, remotely sensed characteristics through the use of the NASA Goddard Satellite Data Simulator Unit. Outputs from high resolution forecasts are compared against radar and satellite observations emphasizing differences in assumed crystal shape and size distribution characteristics.

  16. Comparing Physics Scheme Performance for a Lake Effect Snowfall Event in Northern Lower Michigan

    NASA Technical Reports Server (NTRS)

    Molthan, Andrew; Arnott, Justin M.

    2012-01-01

    High resolution forecast models, such as those used to predict severe convective storms, can also be applied to predictions of lake effect snowfall. A high resolution WRF model forecast model is provided to support operations at NWS WFO Gaylord, Michigan, using a 12 ]km and 4 ]km nested configuration. This is comparable to the simulations performed by other NWS WFOs adjacent to the Great Lakes, including offices in the NWS Eastern Region who participate in regional ensemble efforts. Ensemble efforts require diversity in initial conditions and physics configurations to emulate the plausible range of events in order to ascertain the likelihood of different forecast scenarios. In addition to providing probabilistic guidance, individual members can be evaluated to determine whether they appear to be biased in some way, or to better understand how certain physics configurations may impact the resulting forecast. On January 20 ]21, 2011, a lake effect snow event occurred in Northern Lower Michigan, with cooperative observing and CoCoRaHS stations reporting new snow accumulations between 2 and 8 inches and liquid equivalents of 0.1 ]0.25 h. The event of January 21, 2011 was particularly well observed, with numerous surface reports available. It was also well represented by the WRF configuration operated at NWS Gaylord. Given that the default configuration produced a reasonable prediction, it is used here to evaluate the impacts of other physics configurations on the resulting prediction of the primary lake effect band and resulting QPF. Emphasis here is on differences in planetary boundary layer and cloud microphysics parameterizations, given their likely role in determining the evolution of shallow convection and precipitation processes. Results from an ensemble of seven microphysics schemes and three planetary boundary layer schemes are presented to demonstrate variability in forecast evolution, with results used in an attempt to improve the forecasts in the 2011 ]2012

  17. Land Surface and Atmosphere Impacts on Spaceborne Passive Microwave Observations for Snowfall Estimation

    NASA Astrophysics Data System (ADS)

    Kraatz, S. G.; Zahraei, A.; Mahani, S. E.; Khanbilvardi, R.

    2013-12-01

    Accurate global estimates of precipitation rate will lead to a better understanding of atmospheric circulation and to improve climatology, weather forecasting and climate change studies. Sensitivity of microwave (MW) range of electromagnetic spectra to ice particles and snowflakes might lead us to use satellite-based MW brightness temperature (BT) to study snowfall. However, MW-BT significantly varies in regards to atmosphere and ground conditions (e.g. land coverage). This study will address how remotely sensed MW-BT measurements are affected by ground surface (snow covered vs. no-snow) and atmospheric conditions (hydrometeors vs. clear sky). The study area is located in the Northeastern United States. Multi MW frequencies from the Advanced Microwave Sounding Unit (AMSU), the NOAA-CREST in-situ snow measurement unit - CREST-SAFE (Snow Analysis and Field Experiment), ISCCP (International Satellite Cloud Climatology project), etc, will be used to show the interrelationship between satellite and ground-based retrieved MW observations. A statistical model has been developed to classify different ground and atmosphere scenarios, and derive relationships among different MW frequencies from satellite and in-situ measurements given ground and atmospheric conditions. We concluded that 89, 150, and 183×7 GHz bands are less affected by atmosphere humidity and can be used to measure ground surface and hydrometeors (e.g. ice particles) impacts. While satellite-based 89 GHz has shown a robust relationship with ground conditions, 68% correlation between satellite and ground observations; 150 and 183×7 GHz are 57% and 46% correlated with hydrometeors. Satellite-based 183×1 GHz has the weakest correlation with ground and atmosphere conditions.

  18. Winter leaf reddening in 'evergreen' species.

    PubMed

    Hughes, Nicole M

    2011-05-01

    Leaf reddening during autumn in senescing, deciduous tree species has received widespread attention from the public and in the scientific literature, whereas leaf reddening in evergreen species during winter remains largely ignored. Winter reddening can be observed in evergreen herbs, shrubs, vines and trees in Mediterranean, temperate, alpine, and arctic regions, and can persist for several months before dissipating with springtime warming. Yet, little is known about the functional significance of this colour change, or why it occurs in some species but not others. Here, the biochemistry, physiology and ecology associated with winter leaf reddening are reviewed, with special focus on its possible adaptive function. Photoprotection is currently the favoured hypothesis for winter reddening, but alternative explanations have scarcely been explored. Intraspecific reddening generally increases with sunlight incidence, and may also accompany photosynthetic inferiority in photosynthetically 'weak' (e.g. low-nitrogen) individuals. Red leaves tend to show symptoms of shade acclimation relative to green, consistent with a photoprotective function. However, winter-red and winter-green species often cohabitate the same high-light environments, and exhibit similar photosynthetic capacities. The factors dictating interspecific winter leaf colouration therefore remain unclear. Additional outstanding questions and future directions are also highlighted, and possible alternative functions of winter reddening discussed. PMID:21375534

  19. Total Lightning Observations within Electrified Snowfall using Polarimetric Radar LMA, and NWN Measurements

    NASA Technical Reports Server (NTRS)

    Schultz, Christopher J.; Bruning, Eric C.; Carey, Lawrence D.; Blakeslee, Richard J.

    2013-01-01

    Tall structures play and important role in development of winter time lightning flashes.To what extent still needs to be assessed. Tower initiated flashes typically occur as banded structures pass near/overhead. Hi resolution RHI s from polarimetric radar show that the lightning has a tendency to propagate through layered structures within these snowstorms.

  20. Winter temperature variations over the middle and lower reaches of the Yangtze River since 1736 AD

    NASA Astrophysics Data System (ADS)

    Hao, Z.-X.; Zheng, J.-Y.; Ge, Q.-S.; Wang, W.-C.

    2012-06-01

    We present statistically reconstructed mean annual winter (December-February) temperatures from the middle and lower reaches of the Yangtze River (24° N-34° N, 108° E-123° E within mainland China) extending back to 1736. The reconstructions are based on information regarding snowfall days from historical documents of the Yu-Xue-Fen-Cun archive recorded during the Qing Dynasty (1644-1911). This information is calibrated with regional winter temperature series spanning the period from 1951 to 2007. The gap from 1912 to 1950 is filled using early instrumental observations. With the reference period of 1951-2007, the 18th century was 0.76 °C colder, and the 19th century was 1.18 °C colder. However, since the 20th century, the climate has been in a warming phase, particularly in the last 30 yr, and the mean temperature from 1981 to 2007 was 0.25 °C higher than that of the reference period of 1951-2007, representing the highest temperatures of the past 300 yr. Uncertainty existed for the period prior to 1900, and possible causes of this uncertainty, such as physical processes involved in the interaction between temperature and snowfall days and changing of observers, are discussed herein.

  1. Winter Art Education Project

    ERIC Educational Resources Information Center

    Jokela, Timo

    2007-01-01

    The purpose of this article is to describe how the Department of Art Education at the University of Lapland in Finland has developed winter art as a method of environmental and community-based art education. I will focus on the Snow Show Winter Art Education Project, a training project funded by the European Union and the State Provincial Office…

  2. Evaluation of DFIR and Bush Gauge Snowfall Measurements at Boreal Forest Sites in Saskatchewan/Canada and Valdai/Russia

    NASA Astrophysics Data System (ADS)

    Yang, D.; Smith, C.

    2013-12-01

    Snowfall is important to cold region climate and hydrology including Canada. Large uncertainties and biases exist in gauge-measured precipitation datasets and products. These uncertainties affect important decision-making, water resources assessments, climate change analyses, and calibrations of remote sensing algorithms and land surface models. Efforts have been made at both the national and international levels to quantity the errors/biases in precipitation measurements, such as the WMO Solid Precipitation Intercomparison Experiment (WMO-SPICE). Both the DFIR (double fence intercomparison reference) and the bush shielded gauge have been used in the past as a reference measurement for solid precipitation and they both have been selected as the references for the current SPICE project. Previous analyses of the DFIR vs. the bush (manual Tretyakov) gauge data collected at the Valdai station in Russia suggest DFIR undercatch of snowfall by up to 10% for high wind conditions. A regression relationship between the 2 systems was derived and used for the last WMO gauge intercomparison. Given the importance of the DFIR as the reference for the WMO SPICE project, it is necessary to re-examine and update the DFIR and bush gauge relationship. As part of Canada's contribution to the WMO SPICE project, a test site has been set up by EC/ASTD/WSDT in the southern Canadian Boreal forest to compare the DFIR and bush gauges. This site, called the Caribou Creek, has been installed within a modified young Jack Pine forest stand - north of Prince Albert in Saskatchewan. This study compiles and analyzes recent DFIR and bush gauge data from both the Valdai and Caribou Creek sites. This presentation summarizes the results of data analyses, and evaluates the performance of both references for snowfall observations in the northern regions. The methods and results of this research will directly support the WMO SPICE project and contribute to cold region hydrology and climate change research.

  3. Ground Based In-situ Measurements of Snowfall with a 2D-Video Distrometer on Mt. Zugspitze, Germany

    NASA Astrophysics Data System (ADS)

    Bernauer, F.; Schwinzerl, M.; Huerkamp, K.; Tschiersch, J.

    2014-12-01

    Measuring micro physical properties of snowfall is a challenging task that is essential in many areas of research. Some examples are wet deposition of atmospheric pollution, electromagnetic wave propagation during snowfall, avalanche and glacier research. In recent years the 2D-video-disdrometer (2DVD, Joanneum Research) has been established for ground based in-situ rain measurements. The 2DVD is an optical device that delivers shape, size and velocity information derived from a front and a side view taken from each hydrometeor falling through the sensitive area. In case of snowfall the user has to be aware of certain diffculties that are addressed in this contribution.For our study we installed the 2DVD at the Environmental Research Station Schneefernerhaus (UFS) on Mt. Zugspitze, Germany (2650m a.s.l.). We analyzed a data set consisting of 150 days with snowfall and 70 man made observations including a classification according to the World Meteorologic Organization code 4677. We compared measured micro physical parameters with man made observations of shape, degree of riming and humidity of single hydrometeors and correlated the precipitation rate and total water equivalent from the 2DVD with measurements of a weighing precipitation sensor (in cooperation with the Institute for Geophysics and Meteorology, University Cologne).We show that the implementation of a matching algorithm that finds appropriate pairs of pictures is essential for reliable measurement results. Without the improved matching algorithm the data sets contain about 80% of hydrometeors with extreme geometries and velocities. Applying the new matching algorithm 2DVD measurements and man made observations fit in most of the cases of calm winds. Simply summing up hydrometeor volumes derived from the measured apparent diameters leads to an overestimation of water equivalent by a factor of 10. The measurement of water equivalent is improved significantly with the use of a size-density relation for

  4. Winter and Summer Views of the Salt Lake Region

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Magnificent views of the region surrounding Salt Lake City, Utah are captured in these winter and summer images from the Multi-angle Imaging SpectroRadiometer's vertical-viewing (nadir) camera. Salt Lake City, situated near the southeastern shore of the Great Salt Lake, is host to the 2002 Winter Olympic Games, which open Friday, February 8. Venues for five of the scheduled events are at city (indoor) locations, and five in mountain (outdoor) facilities. All ten can be found within the area contained in these images. Some of the outdoor events take place at Ogden, situated north of Salt Lake City and at Park City, located to the east. Salt Lake City is surrounded by mountains including the Wasatch Range to the east, and the temperature difference between the Great Salt Lake and the overlying atmosphere enhances the moisture content of winter storms. These factors, in combination with natural cloud seeding by salt crystals from the lake, are believed to result in greater snowfall in neighboring areas compared to more distant locales. In addition to the obvious difference in snow cover between the winter and summer views, water color changes in parts of the Great Salt Lake are apparent in these images. The distinctly different coloration between the northern and southern arms of the Great Salt Lake is the result of a rock-filled causeway built in 1953 to support a permanent railroad. The causeway has resulted in decreased circulation between the two arms and higher salinity on the northern side. The southern part of the lake includes the large Antelope Island, and at full resolution a bridge connecting it to the mainland can be discerned. These images are natural color views acquired on February 8, 2001 and June 16, 2001, respectively. Each image represents an area of about 220 kilometers x 285 kilometers. Image courtesy NASA/GSFC/LaRC/JPL, MISR Team.

  5. Declining Sea Ice Extent Links Early Winter Climate to Changing Arctic Lakes

    NASA Astrophysics Data System (ADS)

    Alexeev, V. A.; Arp, C. D.; Jones, B. M.; Cai, L.

    2015-12-01

    Lakes on the Alaskan North Slope regulate surface energy balance and interactions with permafrost as well as providing important habitat. Winter lake ice regimes (floating-ice or bedfast-ice conditions) determine whether lakes develop and maintain taliks and can support overwintering fish habitat. Lake ice thickness is a key variable determining whether a lake has a bedfast or floating-ice regime. Recent observations suggest a trend towards more lakes with floating-ice conditions due to thinner ice growth, but the broader scale associated climate conditions driving these regime shift are less certain. This study finds that the changing arctic summer/fall sea ice conditions might be affecting lake ice thickness on the North Slope. Late ocean freeze-up near the Alaskan coast leads to warmer weather and more snowfall in the early winter. Warmer early winters and thicker snowpack result in thinner lake ice the following winter thus potentially developing more ice-floating lakes before the start of the summer. Experiments with a regional atmospheric model WRF for two years with very different sea ice conditions indicate that the extent of open water next to the North Slope is a crucial factor for developing thicker snowpack, also warmer air temperature in early winter.

  6. The Winter Is Past.

    ERIC Educational Resources Information Center

    Busch, Phyllis S.

    1985-01-01

    Teacher, writer, and naturalist Phyllis S. Busch takes the reader on an early evening woodland walk in March, describing the many changes in plants and animals that are perceptible by sight, smell, and sound as nature awakens from winter. (NEC)

  7. Winter Weather Checklists

    MedlinePlus

    ... Planning Information on Specific Types of Emergencies Winter Weather Checklists Language: English Español (Spanish) Recommend on Facebook ... emergency instructions National Oceanic and Atmospheric Administration (NOAA) weather radio receiver for listening to National Weather Service ...

  8. Weak precipitation, warm winters and springs impact glaciers of south slopes of Mt. Everest (central Himalaya) in the last 2 decades (1994-2013)

    NASA Astrophysics Data System (ADS)

    Salerno, F.; Guyennon, N.; Thakuri, S.; Viviano, G.; Romano, E.; Vuillermoz, E.; Cristofanelli, P.; Stocchi, P.; Agrillo, G.; Ma, Y.; Tartari, G.

    2015-06-01

    Studies on recent climate trends from the Himalayan range are limited, and even completely absent at high elevation (> 5000 m a.s.l.). This study specifically explores the southern slopes of Mt. Everest, analyzing the time series of temperature and precipitation reconstructed from seven stations located between 2660 and 5600 m a.s.l. during 1994-2013, complemented with the data from all existing ground weather stations located on both sides of the mountain range (Koshi Basin) over the same period. Overall we find that the main and most significant increase in temperature is concentrated outside of the monsoon period. Above 5000 m a.s.l. the increasing trend in the time series of minimum temperature (+0.072 °C yr-1) is much stronger than of maximum temperature (+0.009 °C yr-1), while the mean temperature increased by +0.044 °C yr-1. Moreover, we note a substantial liquid precipitation weakening (-9.3 mm yr-1) during the monsoon season. The annual rate of decrease in precipitation at higher elevations is similar to the one at lower elevations on the southern side of the Koshi Basin, but the drier conditions of this remote environment make the fractional loss much more consistent (-47% during the monsoon period). Our results challenge the assumptions on whether temperature or precipitation is the main driver of recent glacier mass changes in the region. The main implications are the following: (1) the negative mass balances of glaciers observed in this region can be more ascribed to a decrease in accumulation (snowfall) than to an increase in surface melting; (2) the melting has only been favoured during winter and spring months and close to the glaciers terminus; (3) a decrease in the probability of snowfall (-10%) has made a significant impact only at glacier ablation zone, but the magnitude of this decrease is distinctly lower than the observed decrease in precipitation; (4) the decrease in accumulation could have caused the observed decrease in glacier flow

  9. American woodcock winter distribution and fidelity to wintering areas

    USGS Publications Warehouse

    Diefenbach, D.R.; Derleth, E.L.; Vander Haegen, W.M.; Nichols, J.D.; Hines, J.E.

    1990-01-01

    We examined winter distribution and fidelity to wintering areas for the American Woodcock (Scolopax minor), which exhibits reversed, sexual size dimorphism. Band-recovery data revealed no difference in winter distributions of different age/sex classes for woodcock from the same breeding areas. Similarly, band recoveries from woodcock banded on wintering grounds revealed no difference in fidelity to wintering sites. Males may winter north of a latitude that is optimal for survival based on physiological considerations, but they gain a reproductive advantage if they are among the first to arrive on the breeding grounds. This may explain our results, which indicate males and females have similar distribution patterns during winter.

  10. Winter QPF Sensitivities to Snow Parameterizations and Comparisons to NASA CloudSat Observations

    NASA Technical Reports Server (NTRS)

    Molthan, Andrew; Haynes, John M.; Jedlovec, Gary J.; Lapenta, William M.

    2009-01-01

    Steady increases in computing power have allowed for numerical weather prediction models to be initialized and run at high spatial resolution, permitting a transition from larger scale parameterizations of the effects of clouds and precipitation to the simulation of specific microphysical processes and hydrometeor size distributions. Although still relatively coarse in comparison to true cloud resolving models, these high resolution forecasts (on the order of 4 km or less) have demonstrated value in the prediction of severe storm mode and evolution and are being explored for use in winter weather events . Several single-moment bulk water microphysics schemes are available within the latest release of the Weather Research and Forecast (WRF) model suite, including the NASA Goddard Cumulus Ensemble, which incorporate some assumptions in the size distribution of a small number of hydrometeor classes in order to predict their evolution, advection and precipitation within the forecast domain. Although many of these schemes produce similar forecasts of events on the synoptic scale, there are often significant details regarding precipitation and cloud cover, as well as the distribution of water mass among the constituent hydrometeor classes. Unfortunately, validating data for cloud resolving model simulations are sparse. Field campaigns require in-cloud measurements of hydrometeors from aircraft in coordination with extensive and coincident ground based measurements. Radar remote sensing is utilized to detect the spatial coverage and structure of precipitation. Here, two radar systems characterize the structure of winter precipitation for comparison to equivalent features within a forecast model: a 3 GHz, Weather Surveillance Radar-1988 Doppler (WSR-88D) based in Omaha, Nebraska, and the 94 GHz NASA CloudSat Cloud Profiling Radar, a spaceborne instrument and member of the afternoon or "A-Train" of polar orbiting satellites tasked with cataloguing global cloud

  11. A coupled atmosphere-river flow simulation in California during the 1994-1995 winter

    SciTech Connect

    Kim, J.; Miller, N.L.

    1995-09-28

    Calculation of river flow is important for managing reservoirs and flood forecasting. In the western United States, a complex terrain which is characterized by steep slopes and narrow valleys often cause a substantial rise of river levels in a short period during heavy precipitation events. Since flood control is one of the major tasks of reservoir operation, inaccurate predictions of precipitation and river flow may cause flooding or waste of water resources. Accurate calculations of river flow need accurate liquid water input to the river system at scales of individual watersheds. Precipitation and snowmelt are the most important natural source of water for a river. Reservoir operations significantly affect river flow in the western United States. Factors such as instantaneous soil water content, vegetation cover, terrain slope and ground water table structure are also crucial for river flow calculation. There are two types of precipitation: rain and snowfall. River flow quickly responds to rainfall while snowfall does not directly affect river flow until it melts afterwards. Therefore, these two types of precipitation must be separately provided to the river flow model for correct calculation of river flows. A large portion of snowfall is accumulated at high terrain during winter months in the western United States. Accumulation of snow causes the river flow to respond to instantaneous precipitation with a certain amount of time lag. During warm springs, large amounts of snowmelt can even cause local flooding. Hence, accurate estimation of snowmelt is another important step for calculating river flows. River flows are affected many different atmospheric and land surface processes. Therefore, a well-designed numerical modeling system which includes atmospheric-surface-hydrologic processes and is coupled to large-scale atmospheric data is an important tool for predicting and diagnosing local river flows and water resources.

  12. Synoptic climatological study on precipitation in the Hokuriku District of Central Japan associated with the cold air outbreak in early winter (With Comparison to that in midwinter for the 1983/1984 winter)

    NASA Astrophysics Data System (ADS)

    Kato, Kuranoshin; Nishimura, Nanako; Haga, Yuichi

    2014-05-01

    In midwinter, heavy snowfall events are often brought in the Japan Sea side of the Japan Islands by the organized convective snowfall systems in the cold air outbreak situations. However, although the air temperature around the Japan Islands is still rather higher from November to early December ("early winter"), the "wintertime pressure pattern" often appears due to the considerable development of the Siberian high already in that season. Since the seasonal cycle in East Asia shows great variety with many rapid seasonal transitions influenced by the Asian monsoon system, detailed comparison of the daily precipitation climatology and the relating atmospheric processes in the cold air outbreak situations between early winter and midwinter would give us an interesting information for comprehending the overall aspects of such seasonal cycle there. Thus the present study firstly examined the daily precipitation climatology mainly at Takada, as an example for Hokuriku District, during the early to mid- winter of 1970/71 to 2009/10. Then the detailed analyses were made for the 1983/1984 winter (one of the coldest winters during that period) based on the operational meteorological data by JMA, including the ocean buoy data in the southern part of the Japan Sea for evaluating the sensible and the latent heat fluxes from the sea (referred to as SH and LH, respectively). The total precipitation at Takada in early winter was as large as in midwinter, although it was brought mainly not as snow but as rain. Such large climatological value was mainly reflected by the precipitation in the "wintertime pressure pattern" with large contribution of the days with more than 30 mm/day. Interestingly, mean daily precipitation in the "wintertime pressure pattern" in early winter was greater than in midwinter. It is noted that such features were generally found even in the latter half of the analysis period when the warmer winter years appeared more frequently than in the former half

  13. Simulation of Annual Snowfall over Colorado using a High Resolution Mesoscale Model and some Impacts of Climate Change using the Pseudo Climate Simulation Method

    NASA Astrophysics Data System (ADS)

    Rasmussen, R.; Grubisic, V.

    2010-09-01

    Snowpack is the most important water resource in the Western United States, and widely regarded as the most vulnerable. It is thus critical to provide water managers the most accurate estimate of how that resource will evolve as the climate changes, including its societal impact. The headwaters region of Colorado that includes, among others, the Colorado, Platte, Rio Grande and Arkansas Rivers, is one of the key source regions for water in the Southwest as ~85% of the streamflow for the Colorado River comes from snowmelt in this region. This region is a particularly difficult area for global climate models to properly handle, with inconsistent snowpack trends in this region from different models despite consistent predictions of temperature increases in this region from all climate models from both the 3rd and 4th IPCC reports (2001, 2007). Observations over the past 50 years in the upper Colorado River basin also reflect the same increasing temperature trend but show no identifiable trends in snowpack (Edwards and Redmond, 2005, Colorado and California Water Users Conference publication). A recent analysis of the 2007 IPCC 4th Assessment global models by Hoerling and Eischeid (2006,Southwest Hydrology) indicates that the combination of increased temperature and weak to no trends in snowfall will produce unprecedented drought conditions over the next 50 years in the Southwest due to a strong increase in evapotranspiration associated with the increased temperature. While the above predictions based on global models indicate dire consequences for the Southwest, it should also be noted that the AR4 indicates that global models typically perform poorly in mountainous regions due to the poor depiction of terrain as well as significant uncertainty in detailed hydrometeorological processes (i.e. cloud/precipitation microphysics, embedded convection and cloud-scale circulations, snowpack and snow ablation, and runoff generation in complex terrain) that currently limit

  14. Altered snowfall and soil disturbance influence the early life stage transitions and recruitment of a native and invasive grass in a cold desert

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Climate change effects on plants are expected to be primarily mediated through early life stage transitions. Snowfall variability, in particular, may have profound impacts on seedling recruitment; structuring plant populations and communities, especially in mid-latitude systems. These water-limi...

  15. Winter depression and diabetes.

    PubMed

    Ernst, Christine R

    2012-12-01

    Depression is a common and often harmful disorder, which is frequently associated with the winter season. Research has shown a link between type 2 diabetes mellitus and depression. Furthermore, diabetics with depression have a higher rate of adverse outcomes. Little has been published regarding the seasonality of depression in diabetics. The case report described in this article concerns a 65-year-old woman with type 2 diabetes and a history of winter depression. Current evidence-based management options are reviewed. PMID:23089656

  16. High Resolution Simulation of Annual Snowfall and Snowpack over Colorado and some Impacts of Climate Change using the Pseudo Climate Simulation Method

    NASA Astrophysics Data System (ADS)

    Rasmussen, R.; Ikeda, K.; Liu, C.; Gochis, D.; Chen, F.; Tewari, M.; Dudhia, J.; Thompson, G.; Barlage, M. J.; Miller, K.; Yates, D.; Grubisic, V.; Arsenault, K.

    2009-12-01

    Snowpack is the most important water resource in the Western United States, and widely regarded as the most vulnerable. It is thus critical to provide water managers the most accurate estimate of how that resource will evolve as the climate changes, including its societal impact. The headwaters region of Colorado that includes, among others, the Colorado, Platte, Rio Grande and Arkansas Rivers, is one of the key source regions for water in the Southwest as ~85% of the streamflow for the Colorado River comes from snowmelt in this region. This region is a particularly difficult area for global climate models to properly handle, with inconsistent snowpack trends in this region from different models despite consistent predictions of temperature increases in this region from all climate models from both the 3rd and 4th IPCC reports (2001, 2007). A recent analysis of the 2007 IPCC 4th Assessment global models by Hoerling and Eischeid (2006,Southwest Hydrology) indicates that the combination of increased temperature and weak to no trends in snowfall will produce unprecedented drought conditions over the next 50 years in the Southwest due to a strong increase in evapotranspiration associated with the increased temperature. While the above predictions based on global models indicate dire consequences for the Southwest, it should also be noted that the AR4 indicates that global models typically perform poorly in mountainous regions due to the poor depiction of terrain as well as significant uncertainty in detailed hydrometeorological processes (i.e. cloud/precipitation microphysics, embedded convection and cloud-scale circulations, snowpack and snow ablation, and runoff generation in complex terrain) that currently limit model simulation skill. Colorado’s headwaters region is dominated by high altitude snow melt, so climate assessments in this region using global models are particularly uncertain. It is therefore critical to examine climate impacts in this region using

  17. Winter Refuge for Aedes aegypti and Ae. albopictus Mosquitoes in Hanoi during Winter

    PubMed Central

    Tsunoda, Takashi; Cuong, Tran Chi; Dong, Tran Duc; Yen, Nguyen Thi; Le, Nguyen Hoang; Phong, Tran Vu; Minakawa, Noboru

    2014-01-01

    Dengue occurs throughout the year in Hanoi, Vietnam, despite winter low temperatures <10°C. During July 2010 to March 2012, we surveyed monthly for Aedes larvae and pupae in 120 houses in 8 Hanoi districts. Aedes albopictus preferred discarded containers in summer and pupal density drastically decreased in winter. Aedes aegypti preferred concrete tanks and this preference increased in winter. Even in winter, the lowest water temperature found in concrete tanks was >14°C, exceeding the developmental zero point of Ae. aegypti. Although jars, drums and concrete tanks were the dominant containers previously (1994–97) in Hanoi, currently the percentage of residences with concrete tanks was still high while jars and drums were quite low. Our study showed that concrete tanks with broken lids allowing mosquitoes access were important winter refuge for Ae. aegypti. We also indicate a concern about concrete tanks serving as foci for Ae. aegypti to expand their distribution in cooler regions. PMID:24752230

  18. Variability in winter climate and winter extremes reduces population growth of an alpine butterfly.

    PubMed

    Roland, Jens; Matter, Stephen F

    2013-01-01

    We examined the long-term, 15-year pattern of population change in a network of 21 Rocky Mountain populations of Parnassius smintheus butterflies in response to climatic variation. We found that winter values of the broadscale climate variable, the Pacific Decadal Oscillation (PDO) index, were a strong predictor of annual population growth, much more so than were endogenous biotic factors related to population density. The relationship between PDO and population growth was nonlinear. Populations declined in years with extreme winter PDO values, when there were either extremely warm or extremely cold sea surface temperatures in the eastern Pacific relative to that in the western Pacific. Results suggest that more variable winters, and more frequent extremely cold or warm winters, will result in more frequent decline of these populations, a pattern exacerbated by the trend for increasingly variable winters seen over the past century. PMID:23600253

  19. A New Standard Installation Method of the Offline Seismic Observation Station in Heavy Snowfall Area of Tohoku Region

    NASA Astrophysics Data System (ADS)

    Hirahara, S.; Nakayama, T.; Hori, S.; Sato, T.; Chiba, Y.; Okada, T.; Matsuzawa, T.

    2015-12-01

    Soon after the 2011 Tohoku earthquake, seismic activity of Tohoku region, NE Japan is induced in the inland area of Akita prefecture and the border area between Fukushima and Yamagata prefectures. We plan to install a total of 80 offline seismic observation stations in these areas for studying the effect of megathrust earthquake on the activities of inland earthquakes. In our project, maintenance will be held twice-a-year for 4 years from 2015 by using 2.0Hz short-period 3-component seismometer, KVS-300 and ultra-low-power data logger, EDR-X7000 (DC12V 0.08W power supply). We installed seismometer on the rock surface or the slope of the natural ground at the possible sites confirmed with low noise level to obtain distinct seismic waveform data. We report an improvement in installation method of the offline seismic observation station in the heavy snowfall area of Tohoku region based on the retrieved data. In the conventional method, seismometer was installed in the hand-dug hole of a slope in case it is not waterproof. Data logger and battery were installed in the box container on the ground surface, and then, GPS antenna was installed on the pole fixed by stepladder. There are risks of the inclination of seismometer and the damage of equipment in heavy snowfall area. In the new method, seismometer is installed in the robust concrete box on the buried basement consists of precast concrete mass to keep its horizontality. Data logger, battery, and GPS antenna are installed on a high place by using a single pole with anchor bolt and a pole mount cabinet to enhance their safety. As a result, total costs of installation are kept down because most of the equipment is reusable. Furthermore, an environmental burden of waste products is reduced.

  20. Teaching Ecology in Winter.

    ERIC Educational Resources Information Center

    Clearing: Nature and Learning in the Pacific Northwest, 1984

    1984-01-01

    Presents ideas for teaching ecology in the winter. Suggested topic areas or units include snow insulation and density, snowflakes and snow crystals, goldenrod galls, bird behavior, survival techniques, bacteriology and decomposition, trees and keying, biomass and productivity, pollution, and soil organisms. A sample student activity sheet is…

  1. The News. Winter 2007

    ERIC Educational Resources Information Center

    Giles, Ray, Ed.

    2007-01-01

    This Winter 2007 quarterly newsletter from the Community College League of California includes: (1) Incumbents: Some Win, Some Lose in November Trustee Elections; (2) Voters Approve $2 Billion in Bonds; (3) Photos from the "Together We Can" conference; (4) Report, Media Criticize Transfer, Completion Rates and Colleges; (5) District Leader…

  2. Winter Playscape Dreaming

    ERIC Educational Resources Information Center

    Keeler, Rusty

    2006-01-01

    Winter, like all seasons, adds a new sense of mystery and discovery to the world of young children. It is the time when they can study snowflakes, find icicles, or observe the birds that share their yards. This article presents ideas and suggestions on how to plan a playscape. A playscape is a man-made seasonal playground for young children. It…

  3. Trends in snowfall versus rainfall in the Western United States--Revisited

    NASA Astrophysics Data System (ADS)

    Dettinger, M. D.; Knowles, N.; Cayan, D. R.

    2015-12-01

    Knowles et al. (J. Climate, 2006) documented long-term (1949-2004) trends in precipitation form, with a smaller fraction of precipitation falling, in recent decades, on days with reported snow compared to days when no snow was reported (and when precipitation was presumably rain). This precipitation-amount-corrected trend was found at three-quarters of 261 cooperative weather stations across the region. The trends correlated with corresponding trends towards warmer winter air temperatures at the weather stations involved. An update of those analyses through the more recent period indicates that the overall swing towards less precipitation fraction occurring on snowy days has continued through the intervening years, with 21st Century rain/snow fractions remaining significantly higher than historical norms at most stations. The same data have also been used to develop site-specific statistical relations between precipitation form (snowy-day precipitation vs purely rainy day) and air temperatures by logistical regressions at over 200 stations across the West, to determine whether the general temperature trends mentioned above have, in fact, been large enough to explain the trending precipitation forms. That is, were the warming trends detected across the West large enough to actually raise temperatures above the local snow-rain thresholds at most stations? The regression relations show that the temperature at which half of the wet days have been snowy historically varies, from station to station, across a range from -2ºC to +4ºC. Thus at some stations winter storm temperatures would have to rise above about -2ºC to markedly impact precipitation forms, while at other stations, temperature had to rise above +4ºC. Nonetheless, observed temperature trends since 1950 have been sufficient to explain the observed regional precipitation-form trends. The fitted precipitation form-temperature relations also provide a basis for estimating precipitation forms in hydrological

  4. Lessons learned from the snow emergency management of winter season 2008-2009 in Piemonte

    NASA Astrophysics Data System (ADS)

    Bovo, Dr.; Pelosini, Dr.; Cordola, Dr.

    2009-09-01

    The winter season 2008-2009 has been characterized by heavy snowfalls over the whole Piemonte, in the Western Alps region. The snowfalls have been exceptional because of their earliness, persistence and intensity. The impact on the regional environment and territory has been relevant, also from the economical point of view, as well as the effort of the people involved in the forecasting, prevention and fighting actions. The environmental induced effects have been shown until late spring. The main critical situations have been arisen from the snowfalls earliness in season, the several snow precipitation events over the plains, the big amount of snow accumulation on the ground, as well as the anomaly with respect to the last 30 years climatic trend of snow conditions in Piemonte. The damage costs to the public property caused by the snowfalls have been estimated by the Regione Piemonte to be 470 million euros, giving evidence of the real emergency dimension of the event, never occurred during the last 20 years. The technical support from the Regional Agency for Environmental Protection of Regione Piemonte (Arpa Piemonte) to the emergency management allowed to analyse and highlight the direct and induced effects of the heavy snowfalls, outlining risk scenarios characterized by different space and time scales. The risk scenarios deployment provided a prompt recommendation list, both for the emergency management and for the natural phenomena evolution surveillance planning to assure the people and property safety. The risk scenarios related to the snow emergency are different according to the geographical and anthropic territory aspects. In the mountains, several natural avalanche releases, characterized frequently by a large size, may affect villages, but they may also interrupt the main and secondary roads both down in the valleys and small villages road access, requiring a long time for the complete and safe snow removal and road re-opening. The avalanches often

  5. Titan's Winter Polar Vortex

    NASA Technical Reports Server (NTRS)

    Flasar, F.M.; Achterberg, R.K.; Schinder, P.J.

    2008-01-01

    Titan's atmosphere has provided an interesting study in contrasts and similarities with Earth's. While both have N$_2$ as the dominant constituent and comparable surface pressures $\\sim1$ bar, Titan's next most abundant molecule is CH$_4$, not O$_2$, and the dissociative breakup of CH$_4$ and N$_2$ by sunlight and electron impact leads to a suite of hydrocarbons and nitriles, and ultimately the photochemical smog that enshrouds the moon. In addition, with a 15.95-day period, Titan is a slow rotator compared to Earth. While the mean zonal terrestrial winds are geostrophic, Titan's are mostly cyclostrophic, whipping around the moon in as little as 1 day. Despite the different dynamical regime, Titan's winter stratosphere exhibits several characteristics that should be familiar to terrestrial meteorologists. The cold winter pole near the 1 -mbar level is circumscribed by strong winds (up to 190 m/s) that act as a barrier to mixing with airmasses at lower latitudes. There is evidence of enhancement of several organic species over the winter pole, indicating subsidence. The adiabatic heating associated with this subsidence gives rise to a warm anomaly at the 0.01-mbar level, raising the stratopause two scale heights above its location at equatorial latitudes. Condensate ices have been detected in Titan's lower stratosphere within the winter polar vortex from infrared spectra. Although not always unambiguously identified, their spatial distribution exhibits a sharp gradient, decreasing precipitously across the vortex away from the winter pole. The interesting question of whether there is important heterogeneous chemistry occurring within the polar vortex, analogous to that occurring in the terrestrial polar stratospheric clouds in the ozone holes, has not been addressed. The breakup of Titan's winter polar vortex has not yet been observed. On Earth, the polar vortex is nonlinearly disrupted by interaction with large-amplitude planetary waves. Large-scale waves have not

  6. Deciduous Plant Twigs in Winter

    ERIC Educational Resources Information Center

    Clark, Eloise

    1977-01-01

    Describing, via illustration and narrative, the winter twigs found in the U.S., this article presents a sophisticated discussion of: beech, white ash, aspen, sycamore, red oak, butternut, and other winter twigs. (JC)

  7. Winter Cardiovascular Diseases Phenomenon

    PubMed Central

    Fares, Auda

    2013-01-01

    This paper review seasonal patterns across twelve cardiovascular diseases: Deep venous thrombosis, pulmonary embolism, aortic dissection and rupture, stroke, intracerebral hemorrhage, hypertension, heart failure, angina pectoris, myocardial infarction, sudden cardiac death, venricular arrythmia and atrial fibrillation, and discuss a possible cause of the occurrence of these diseases. There is a clear seasonal trend of cardiovascular diseases, with the highest incidence occurring during the colder winter months, which have been described in many countries. This phenomenon likely contributes to the numbers of deaths occurring in winter. The implications of this finding are important for testing the relative importance of the proposed mechanisms. Understanding the influence of season and other factors is essential when seeking to implement effective public health measures. PMID:23724401

  8. Winter Wilderness Travel and Camping.

    ERIC Educational Resources Information Center

    Gilchrest, Norman

    Knowledge and skill are needed for safe and enjoyable travel and camping in the wilderness in winter. The beauty of snow and ice, reduced human use, and higher tolerance of animals toward humans make the wilderness attractive during winter. The uniqueness of winter travel presents several challenges that are not present in other seasons. Safety is…

  9. Patterns and controls of winter carbon dioxide emissions and microbial biomass C and N, in two arctic ecosystem types under varying snow regimes

    NASA Astrophysics Data System (ADS)

    Larsen, K. S.

    2003-04-01

    In a manipulative study, snow fences were put up in sub arctic birch forest and dry heath areas near Abisko, Northern Sweden, increasing the natural snow-cover by 5-35 cm. In early March, CO2 fluxes were 77% and 157% higher in the snow-fenced areas (birch and heath, respectively) and in the snowmelt period from April to May there was a tendency to higher effluxes of CO2 in patches with increased snow-cover. This indicates that small increases in winter snowfall have the potential to increase the CO2 loss substantially from these ecosystems during the off-season. CO2 fluxes integrated over 22 days in April-May at the heath site constituted 8% of growing season net primary production at a nearby heath site, showing that a substantial part of annual CO2 loss may take place during the early spring. In a second study, measurements of CO2 emissions from birch and heath ecosystems situated across a natural snow-cover gradient were performed. The results of this study corroborates with the findings in the snow fence study, showing consistently higher fluxes from sites with higher snow depths. The microbial biomass N and P were determined in both studies and were consistently high in the sub nivean soils compared to summer estimates, indicating that microbes provide a significant buffer limiting the export of mineral nutrients in the snowmelt period. A significant decrease in microbial biomass was observed as plots became snow free at the heath site. Although such decreases have been suggested to be caused by freeze-thaw cycles, this cannot fully explain the observation in this study. The first spring thaw and the transition from constant, sub-zero temperatures and a constant water regime to more variable conditions, and possibly increased grazing by nematodes and protozoans, may also play and important role controlling the microbial population during and after snowmelt.

  10. Features of air masses associated with the deposition of Pseudomonas syringae and Botrytis cinerea by rain and snowfall

    PubMed Central

    Monteil, Caroline L; Bardin, Marc; Morris, Cindy E

    2014-01-01

    Clarifying the role of precipitation in microbial dissemination is essential for elucidating the processes involved in disease emergence and spread. The ecology of Pseudomonas syringae and its presence throughout the water cycle makes it an excellent model to address this issue. In this study, 90 samples of freshly fallen rain and snow collected from 2005–2011 in France were analyzed for microbiological composition. The conditions favorable for dissemination of P. syringae by this precipitation were investigated by (i) estimating the physical properties and backward trajectories of the air masses associated with each precipitation event and by (ii) characterizing precipitation chemistry, and genetic and phenotypic structures of populations. A parallel study with the fungus Botrytis cinerea was also performed for comparison. Results showed that (i) the relationship of P. syringae to precipitation as a dissemination vector is not the same for snowfall and rainfall, whereas it is the same for B. cinerea and (ii) the occurrence of P. syringae in precipitation can be linked to electrical conductivity and pH of water, the trajectory of the air mass associated with the precipitation and certain physical conditions of the air mass (i.e. temperature, solar radiation exposure, distance traveled), whereas these predictions are different for B. cinerea. These results are pertinent to understanding microbial survival, emission sources and atmospheric processes and how they influence microbial dissemination. PMID:24722630

  11. Winter and Summer Views of the Salt Lake Region

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Magnificent views of the region surrounding Salt Lake City, Utah are captured in these winter and summer images from the Multi-angle Imaging SpectroRadiometer's vertical-viewing (nadir) camera. Salt Lake City, situated near the southeastern shore of the Great Salt Lake, is host to the 2002 Winter Olympic Games, which open Friday, February 8. Venues for five of the scheduled events are at city (indoor) locations, and five in mountain (outdoor) facilities. All ten can be found within the area contained in these images. Some of the outdoor events take place at Ogden, situated north of Salt Lake City and at Park City, located to the east.

    Salt Lake City is surrounded by mountains including the Wasatch Range to the east, and the temperature difference between the Great Salt Lake and the overlying atmosphere enhances the moisture content of winter storms. These factors, in combination with natural cloud seeding by salt crystals from the lake, are believed to result in greater snowfall in neighboring areas compared to more distant locales.

    In addition to the obvious difference in snow cover between the winter and summer views, water color changes in parts of the Great Salt Lake are apparent in these images. The distinctly different coloration between the northern and southern arms of the Great Salt Lake is the result of a rock-filled causeway built in 1953 to support a permanent railroad. The causeway has resulted in decreased circulation between the two arms and higher salinity on the northern side. The southern part of the lake includes the large Antelope Island, and at full resolution a bridge connecting it to the mainland can be discerned.

    These images are natural color views acquired on February 8, 2001 and June 16, 2001, during Terra orbits 6093 and 7957, respectively. Each image represents an area of about 220 kilometers x 285 kilometers.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth

  12. The History of Winter: A Professional Development "Teacher as Scientist" Experiential Learning Field Experience.

    NASA Astrophysics Data System (ADS)

    Gabrys, R. E.

    2007-12-01

    ) Program, the Global Snowflake Network (GSN) launched in the winter of 2006 engages an international audience including both formal and informal education groups. The goal is to provide an interactive online data resource in science and education for the characterization of snowfall and related weather systems. The Global Snowflake Network has been accepted as an education outreach proposal for the International Polar Year. Collaborations with other agencies and universities also with IPY-accepted proposals are now underway. HOW and the GSN are endorsed by the NASA Goddard Education Office and many of the Goddard Snow and Ice Team scientists. Together these programs offer a unique, sustainable, and proven outreach for the Cryosphere research program. Snowflakes are like frozen data points, their shape is a record of atmospheric conditions at the time of their formation. The shapes of snowflakes vary over the winter season, with the source of a weather system and over the course of a given snowfall. The objective of the Global Snowflake Network (GSN) is to create a global ground team of teachers, students, families, and researchers worldwide to identify snowflake types during the progress of snowfalls. The result is a unique and scientifically valid resource useful to meteorology and scientific modeling of Earth's Hydrosphere. The Global Snowflake Network (GSN), simultaneously a science program and an education program is presented as a simple, scientifically valid project that has the potential to spread the IPY message and produce a lasting resource to further scientific understanding of Earth's hydrology through the study of snow.

  13. Winter Frost and Fog

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This somewhat oblique blue wide angle Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the 174 km (108 mi) diameter crater, Terby, and its vicinity in December 2004. Located north of Hellas, this region can be covered with seasonal frost and ground-hugging fog, even in the afternoon, despite being north of 30oS. The subtle, wavy pattern is a manifestation of fog.

    Location near: 28oS, 286oW Illumination from: upper left Season: Southern Winter

  14. Variation In Winter Hardiness Among Safflower Accessions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fall planted safflower (Carthamus tinctorius L.) would provide management alternatives in crop rotations and potentially increase yield. Our objective was to relate several fall growth factors to winter survival in a diverse set of 11 safflower accessions grown at Central Ferry and Pullman WA, USA....

  15. Winter wheat yield response to available water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dryland winter wheat yields in eastern Colorado can vary greatly from year to year and are primarily limited by available water supplies. Yields increase linearly with water use at an average rate of 4.7 bu/a per inch of water used after the first 5 inches of water use. An Excel-based spreadsheet ca...

  16. The Winter Olympics--On Ice.

    ERIC Educational Resources Information Center

    Hoover, Barbara G.

    1998-01-01

    Describes several science activities designed around the upcoming Winter Olympics ice skating events which demonstrate the scientific principles behind the sport. Students learn that increasing the pressure on ice will lead to the ice melting, the principle involved in the spinning swing, and the technology of skates and skating outfits. (PVD)

  17. Spirit's Winter Work Site

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Annotated Version

    This portion of an image acquired by the Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment camera shows the Spirit rover's winter campaign site. Spirit was parked on a slope tilted 11 degrees to the north to maximize sunlight during the southern winter season. 'Tyrone' is an area where the rover's wheels disturbed light-toned soils. Remote sensing and in-situ analyses found the light-toned soil at Tyrone to be sulfate rich and hydrated. The original picture is catalogued as PSP_001513_1655_red and was taken on Sept. 29, 2006.

    NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace and Technology Corp., Boulder, Colo.

  18. Impacts of a changing winter precipitation regime on the Great Snowforest of British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Knudsvig, H.; Dery, S. J.; Coxson, D.

    2012-12-01

    Rising air temperatures have profoundly impacted British Columbia (BC) mountain ecosystems, including its Interior Wetbelt. This region supports the sole Interior Temperate Rainforest (ITR), or perhaps more appropriately "snowforest", of North America. This snowforest encompasses about 30,500 km2 and contains Western redcedar (Thuja plicata) and western hemlock (Tsuga heteropylla) in excess of 1500 years old. This region is projected to be one of the more vulnerable biogeoclimatic zones in BC due to forest operations and climate change. Loss of snow as a storage medium has the potential to negatively affect the forest. A decrease in snow water equivalent (SWE) has the potential to decrease soil moisture values; impacts of decreased water availability in this region have the possibility to affect soil moisture storage, vegetative species composition, flora and fauna interdependence, and pathogen outbreaks. Given the projected climate change in high latitude and altitude areas, this project analyzes the contemporary and potential future climate of BC's Interior Wetbelt and explores the possible environmental and ecohydrological impacts of climate change on the snowforest. Models project an increase in air temperature and precipitation but a decrease in snowfall in this region. Analyses of the snow depth, SWE, and temperature from the Upper Fraser River Basin automated snow pillow sites of the BC River Forecast Centre (RFC) were conducted; snow depth, SWE, and temperature were also measured at the field site via automated weather stations and bi-monthly snow surveys. Surveys recorded depth and SWE after observed peak accumulation and continued until snowpack was depleted in 80% of the field site. To determine the influence of precipitation on the soil moisture levels in the ITR, soil moisture and water table levels were measured for the 2011-12 water year in addition to meteorological conditions; snow, spring water, and near surface ground water samples were collected

  19. Yield and yield components of winter-type safflower

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Safflower (Carthamus tinctorius L.) is a minor yet widely grown oil seed crop adapted to semi-arid regions. The nascent development of winter adapted safflower, allowing fall planting,could substantially increase seed production over spring planting. In this study four winter type safflower accessi...

  20. Measuring Transpiration to Regulate Winter Irrigation Rates

    SciTech Connect

    Samuelson, Lisa

    2006-11-08

    Periodic transpiration (monthly sums) in a young loblolly pine plantation between ages 3 and 6 was measured using thermal dissipation probes. Fertilization and fertilization with irrigation were better than irrigation alone in increasing transpiration of young loblolly pines during winter months, apparently because of increased leaf area in fertilized trees. Irrigation alone did not significantly increase transpiration compared with the non-fertilized and non-irrigated control plots.

  1. The Influence of El Niño and La Niña on Winter Climate Conditions at 138 Ski Resorts in Western North America

    NASA Astrophysics Data System (ADS)

    Pidwirny, M. J.; Mei Turney, A.

    2014-12-01

    This research examines the effect El Niño and La Niña have on the climate conditions of 138 ski resorts in western North America. Using ClimateWNA, monthly values for snowfall and degree days < 0°C (a measure of winter season coldness) were generated for the mid-slope elevation of the resorts for the primary ski season months of December, January, February, and March. From this data, composite values were computed by summing the four months analyzed for each of the two variables, with the December value coming from the previous year. Regression analysis was used to see if a relationship exists between the two climate variables and a summed composite of the monthly Southern Oscillation Index (SOI) for the same four months. Correlation coefficients were determined by regressing the observations for the time period 1935 to 2012. The correlation coefficients were then mapped using ARCGIS to display possible spatial patterns across the study area. Different map symbols were used to identify whether the correlation coefficient was positive or negative, and whether it fell within four levels of statistical significance: P ≥ 0.01, P < 0.01, P < 0.001, and P < 0.0001. Correlation coefficients with probability values equal to P ≥ 0.01 were considered not significant on the map. For the variable degree days < 0°C, resorts located in British Columbia, Alberta, Washington, and coastal south Oregon generally had warmer than usual winters during El Niño events and colder winters when SOI values suggested the occurrence of La Niña. A single resort, Ski Apache in New Mexico showed the opposite trend. Snowfall was found to be higher during La Niña events and lower with El Niño events for a number of resorts above 42° N latitude. Further, the strength of these correlations generally decreased with distance from the coast. Resorts in New Mexico and Arizona generally had more snowfall with El Niño and less snowfall with La Niña.

  2. Winter 1994 Weather and Ice Conditions for the Laurentian Great Lakes.

    NASA Astrophysics Data System (ADS)

    Assel, Raymond A.; Janowiak, John E.; Young, Sharolyn; Boyce, Daron

    1996-01-01

    The Laurentian Great Lakes developed their most extensive ice cover in over a decade during winter 1994 [December-February 1993/94 (DJF 94)]. Extensive midlake ice formation started the second half of January, about 2 weeks earlier than normal. Seasonal maximal ice extent occurred in early February, again about 2 weeks earlier than normal. Winter 1994 maximum (normal) ice coverages on the Great Lakes are Lake Superior 96% (75%), Lake Michigan 78% (45%), Lake Huron 95% (68%), Lake Erie 97% (90%), and Lake Ontario 67% (24%). Relative to the prior 31 winters (1963-93), the extent of seasonal maximal ice cover for winter 1994 for the Great Lakes taken as a unit is exceeded by only one other winter (1979); however, other winters for individual Great Lakes had similar maximal ice covers.Anomalously strong anticyclonic circulation over the central North Pacific (extending to the North Pole) and an abnormally strong polar vortex centered over northern Hudson Bay combined to produce a circulation pattern that brought frequent air masses of Arctic and polar origin to the eastern third of North America. New records were set for minimum temperatures on 19 January 1994 at many locations in the Great Lakes region. A winter severity index consisting of the average November-February air temperatures averaged over four sites on the perimeter of the Great Lakes (Duluth, Minnesota; Sault Ste. Marie, Michigan; Detroit, Michigan; and Buffalo, New York) indicates that winter 1994 was the 21st coldest since 1779. The unseasonably cold air temperatures produced much-above-normal ice cover over the Great Lakes and created problems for lake shipping. Numerous fatalities and injuries were attributed to the winter weather, which included several ice and snow storms. The much-below-normal air temperatures resulted in enhanced lake-effect snowfall along downwind lake shores, particularly during early to midwinter, prior to extensive ice formation in deeper lake areas. The low air temperatures

  3. The Excess Winter Deaths Measure

    PubMed Central

    Gasparrini, Antonio

    2016-01-01

    Background: Excess winter deaths, the ratio between average daily deaths in December–March versus other months, is a measure commonly used by public health practitioners and analysts to assess health burdens associated with wintertime weather. We seek to demonstrate that this measure is fundamentally biased and can lead to misleading conclusions about health impacts associated with current and future winter climate. Methods: Time series regression analysis of 779,372 deaths from natural causes in London over 15 years (1 August 1997–31 July 2012),collapsed by day of death and linked to daily temperature values. The outcome measures were the excess winter deaths index, and daily and annual deaths attributable specifically to cold. Results: Most of the excess winter deaths are driven by cold: The excess winter deaths index decreased from 1.19 to 1.07 after excluding deaths attributable to low temperatures. Over 40% of cold-attributable deaths occurred outside of the December–March period, leading to bias in the excess winter deaths measure. Although there was no relationship between winter severity and annual excess winter deaths, there was a clear correlation with annual cold-attributable deaths. Conclusions: Excess winter deaths is not an appropriate indicator of cold-related health impacts, and its use should be discontinued. We advocate alternative measures. The findings we present bring into doubt previous claims that cold-related deaths in the UK will not reduce in future as a result of climate change. PMID:26986872

  4. Winter fuels report

    SciTech Connect

    Not Available

    1990-11-29

    The Winter Fuels Report is intended to provide concise, timely information to the industry, the press, policymakers, consumers, analysts, and state and local governments on the following topics: distillate fuel oil net production, imports and stocks for all PADD's and product supplied on a US level; propane net product supplied on a US level; propane net production, imports and stocks for Petroleum Administration for Defense Districts (PADD) I, II, and III; natural gas supply and disposition and underground storage for the United States and consumption for all PADD's; residential and wholesale pricing data for propane and heating oil for those states participating in the joint Energy Information Administration (EIA)/State Heating Oil and Propane Program; crude oil and petroleum price comparisons for the United States and selected cities; and US total heating degree-days by city. 27 figs, 12 tabs.

  5. Winter weather scorecard

    NASA Astrophysics Data System (ADS)

    Last fall's 3-month winter weather prediction by National Weather Service (NWS) forecasters was not terrific, but it was not too far off the mark, either. A comparison of the predicted temperatures and precipitation (Eos, December 25, 1984, p. 1241) to the observed conditions (see Figures 1 and 2) during the months of December, January, and February shows that the forecasters were generally correct where they were most confident in their predictions.According to Donald Gilman, chief of the Predictions Branch at NWS's National Climate Analysis Center, the overall temperature forecast was probably better than that for precipitation. “The temperature forecast was pretty good in the West,” said Gilman. “East of the Mississippi, however, was a mixed picture.”

  6. Spirit Scans Winter Haven

    NASA Technical Reports Server (NTRS)

    2006-01-01

    At least three different kinds of rocks await scientific analysis at the place where NASA's Mars Exploration Rover Spirit will likely spend several months of Martian winter. They are visible in this picture, which the panoramic camera on Spirit acquired during the rover's 809th sol, or Martian day, of exploring Mars (April 12, 2006). Paper-thin layers of light-toned, jagged-edged rocks protrude horizontally from beneath small sand drifts; a light gray rock with smooth, rounded edges sits atop the sand drifts; and several dark gray to black, angular rocks with vesicles (small holes) typical of hardened lava lie scattered across the sand.

    This view is an approximately true-color rendering that combines images taken through the panoramic camera's 753-nanometer, 535-nanometer, and 432-nanometer filters.

  7. Winter Survival: A Consumer's Guide to Winter Preparedness.

    ERIC Educational Resources Information Center

    Department of Energy, Washington, DC.

    This booklet discusses a variety of topics to help consumers prepare for winter. Tips for the home include: winterizing the home, dealing with a loss of heat or power failure, and what you need to have on hand. Another section gives driving tips and what to do in a storm. Health factors include suggestions for keeping warm, signs and treatment for…

  8. Do High-elevation Lakes Record Variations in Snowfall and Atmospheric Rivers in the Sierra Nevada of California?

    NASA Astrophysics Data System (ADS)

    Ashford, J.; Sickman, J. O.; Lucero, D. M.

    2014-12-01

    Understanding the underlying causes of interannual variation in snowfall and extreme hydrologic events in the Sierra Nevada is hampered by short instrumental records and the difficulties in reconstructing climate using a traditional paleo-record such as tree-rings. New paleo proxies are needed to provide a record of snowpack water content and extreme precipitation events over millennial timescales which can be used to test hypotheses regarding teleconnections between Pacific climate variability and water supply and flood risk in California. In October 2013 we collected sediment cores from Pear Lake (z = 27 m), an alpine lake in Sequoia National Park. The cores were split and characterized by P-wave velocity, magnetic susceptibility and density scanning. Radiocarbon dates indicate that the Pear Lake cores contain a 13.5K yr record of lake sediment. In contrast to other Sierra Nevada lakes previously cored by our group, high-resolution scanning revealed alternating light-dark bands (~1 mm to 5 mm thick) for most of the Pear Lake core length. This pattern was interrupted at intervals by homogenous clasts (up to 75 mm thick) ranging in grain size from sand to gravel up to 1 cm diameter. We hypothesize that the light-dark banding results from the breakdown of persistent hypolimnetic anoxia during spring snowmelt and autumn overturn. We speculate that the thicknesses of the dark bands are controlled by the duration of anoxia which in turn is controlled by the volume and duration of snowmelt. The sand to gravel sized clasts are most likely associated with extreme precipitation events resulting from atmospheric rivers intersecting the southern Sierra Nevada. We hypothesize that centimeter-sized clasts are deposited in large avalanches and that the sands are deposited in large rain events outside of the snow-cover period.

  9. Winter climate limits subantarctic low forest growth and establishment.

    PubMed

    Harsch, Melanie A; McGlone, Matt S; Wilmshurst, Janet M

    2014-01-01

    Campbell Island, an isolated island 600 km south of New Zealand mainland (52 °S, 169 °E) is oceanic (Conrad Index of Continentality  =  -5) with small differences between mean summer and winter temperatures. Previous work established the unexpected result that a mean annual climate warming of c. 0.6 °C since the 1940's has not led to upward movement of the forest limit. Here we explore the relative importance of summer and winter climatic conditions on growth and age-class structure of the treeline forming species, Dracophyllum longifolium and Dracophyllum scoparium over the second half of the 20th century. The relationship between climate and growth and establishment were evaluated using standard dendroecological methods and local climate data from a meteorological station on the island. Growth and establishment were correlated against climate variables and further evaluated within hierarchical regression models to take into account the effect of plot level variables. Winter climatic conditions exerted a greater effect on growth and establishment than summer climatic conditions. Establishment is maximized under warm (mean winter temperatures >7 °C), dry winters (total winter precipitation <400 mm). Growth, on the other hand, is adversely affected by wide winter temperature ranges and increased rainfall. The contrasting effect of winter warmth on growth and establishment suggests that winter temperature affects growth and establishment through differing mechanisms. We propose that milder winters enhance survival of seedlings and, therefore, recruitment, but increases metabolic stress on established plants, resulting in lower growth rates. Future winter warming may therefore have complex effects on plant growth and establishment globally. PMID:24691026

  10. Duration of prepupal summer dormancy regulates synchronization of adult diapause with winter temperatures in bees of the genus Osmia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Osmia (Osmia) bees are strictly univoltine and winter as diapausing adults. In these species, the timing of adult eclosion with the onset of wintering conditions is critical, because adults exposed to long pre-wintering periods show increased lipid loss and winter mortality. Populations from warm ar...

  11. Phenological and ecological consequences of changes in winter snowpack in the Colorado Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Inouye, D. W.; McKinney, A. M.

    2012-12-01

    The date the snowpack disappears in spring is an important seasonal event at high altitudes because it determines the beginning of the growing season, which in turn influences the phenology of plant growth and flowering, and thus the availability of these resources for animal consumers. At our study site at 2,900m in the Colorado Rocky Mountains, the Rocky Mountain Biological Laboratory, snowmelt now averages two weeks earlier than in 1975. Earlier snowmelt results from a combination of lower snowfall (38 cm less since 1975), dust storms (increasing in frequency, which reduces the snowpack albedo), and warmer spring temperatures (April minimum temperature has increased 3.1°C since 1973; 2012 April mean temperature was 3.4°C above the 38-year mean). There is also a trend of increasing annual precipitation falling as rain instead of snow. We have monitored flowering phenology and abundance for about 100 species of plants in permanent plots since 1973, and use this record to look at how the change in timing of snowmelt has affected flowering. There is significant variation among years in flowering phenology (e.g., about six weeks difference between 2011 and 2012), with a mid-season decline in flowering abundance becoming apparent as the growing season starts earlier. The date of the last hard frost has not been changing in concert with the earlier growing season, with the consequence that many species now have flower buds developed that are then damaged or killed by frost. In 2012, snowmelt date was 23 April, and frost events on 27 May (-11.7°C) and 11 June (-5.6°C) did significant damage to vegetation of some species and to flower buds of many species. For example, flower abundance of the aspen sunflower Helianthella quinquenervis was 0.002% of 2011's flowering. In the absence of seed production, the demography of some plant species is likely being affected. Some animal species are also being affected by the changes in length and temperature of winter. New

  12. Origin of the F-Layer by ``Snowfall'' in the Earth's Core

    NASA Astrophysics Data System (ADS)

    Hernlund, J. W.; Li, J.; Armentrout, M. M.; Buono, A. S.; Chen, B.; Durand, S.; Gaeman, J.; Pigott, J. S.; Waszek, L.; Zheng, Z.

    2010-12-01

    Recent seismological observations of phases reflecting (PKiKP), diffracting (PKPdiff), or going through the inner core (PKIKP) called for modification of PREM at the top of the Inner Core Boundary (ICB). Both the AK135 and PREM2 models proposed a flattened P-wave velocity gradient relative to PREM in the ~200 km region above the ICB, often referred to as the F-layer. This reduced velocity gradient implies density stratification, which may reflect a gradient in the light element concentration decreasing from the top of the F-layer to the ICB. Here we propose a mechanism to generate a chemical stratification in the F-layer through crystallization of solid iron “snow” at the top of the F-layer, which then precipitates, partially dissolves, and eventually accumulates at the ICB to produce the F-layer and contribute to the growth of the inner core. The formation of iron “snow” in the outer core (OC) requires that the core geotherm intercepts the FeX liquidus, where X is an alloying light element, to create a region of stability for solid iron at the base of the OC. This study examines two potential scenarios in which iron “snowfall” might occur in the F-layer. The first scenario involves the FeX liquidus gradient decreasing or even changing sign such that a region of solid stability is created at the top of the F-layer. This behavior is observed in the Fe-S binary system at lower pressures and has been proposed to cause “snowing” in the interiors of Mercury and Ganymede. In the second case, the outer core temperature may increase relative to the FeX liquidus near the ICB due to viscomagnetic heating. Results based on mineral physics calculations of an iron-sulfur binary system show that an F-layer composition ranging from 7.2 wt% S at the top of the F-layer to 5.7 wt% S at the ICB is sufficient to explain the Vp structure of the F-layer in AK135. In these calculations, the density and bulk modulus as a function of depth were determined using the 3rd

  13. Ocean-Atmosphere Environments of Antarctic-Region Cold-Air Mesocyclones: Evaluation of Reanalyses for Contrasting Adjacent 10-Day Periods ("Macro-Weather") in Winter.

    NASA Astrophysics Data System (ADS)

    Carleton, A. M.; Auger, J.; Birkel, S. D.; Maasch, K. A.; Mayewski, P. A.; Claud, C.

    2015-12-01

    Mesoscale cyclones in cold-air outbreaks (mesocyclones) feature in the weather and climate of the Antarctic (e.g., Ross Sea) and sub-antarctic (Drake Passage). They adversely impact field operations, and influence snowfall, the ice-sheet mass balance, and sea-air energy fluxes. Although individual mesocyclones are poorly represented on reanalyses, these datasets robustly depict the upper-ocean and troposphere environments in which multiple mesocyclones typically form. A spatial metric of mesocyclone activity—the Meso-Cyclogenesis Potential (MCP)—used ERA-40 anomaly fields of: sea surface temperature (SST) minus marine air temperature (MAT), near-surface winds, 500 hPa air temperature, and the sea-ice edge location. MCP maps composited by teleconnection phases for 1979-2001, broadly correspond to short-period satellite "climatologies" of mesocyclones. Here, we assess 3 reanalysis datasets (CFSR, ERA-I and MERRA) for their reliably to depict MCP patterns on weekly to sub-monthly periods marked by strong regional shifts in mesocyclone activity (frequencies, track densities) occurring during a La Niña winter: June 21-30, 1999 (SE Indian Ocean) and September 1-10, 1999 (Ross Sea sector). All reanalyses depict the marked variations in upper ocean and atmosphere variables between adjacent 10-day periods. Slight differences may owe to model resolution or internal components (land surface, coupled ocean models), and/or how the observations are assimilated. For June 21-30, positive SST-MAT, southerly winds, proximity to the ice edge, and negative T500, accompany increased meso-cyclogenesis. However, for September 1-10, surface forcing does not explain frequent comma cloud "polar lows" north-east of the Ross Sea. Inclusion of the upper-level diffluence (e.g., from Z300 field) in the MCP metric, better depicts the observed mesocyclone activity. MCP patterns on these "macro-weather" time scales appear relatively insensitive to the choice of reanalysis.

  14. Winter fuels report

    SciTech Connect

    Not Available

    1990-10-04

    The Winter Fuels Report is intended to provide concise, timely information to the industry, the press, policymakers, consumers, analysts, and state and local governments on the following topics: distillate fuel oil net production, imports and stocks for all PADD's and product supplied on a US level; propane net production, imports and stocks for Petroleum Administration for Defense Districts (PADD) I, II, and III; natural gas supply and disposition, underground storage, and consumption for all PADD's; residential and wholesale pricing data for propane and heating oil for those states participating in the joint Energy Information Administration (EIA)/State Heating Oil and Propane Program; crude oil price comparisons for the United States and selected cities; and US total heating degree-days by city. This report will be published weekly by the EIA starting the first week in October 1990 and will continue until the first week in April 1991. The data will also be available electronically after 5:00 p.m. on Thursday during the heating season through the EIA Electronic Publication System (EPUB). 12 tabs.

  15. Surgical Risks Associated with Winter Sport Tourism

    PubMed Central

    Sanchez, Stéphane; Payet, Cécile; Lifante, Jean-Christophe; Polazzi, Stéphanie; Chollet, François; Carty, Matthew J; Duclos, Antoine

    2015-01-01

    Background Mass tourism during winter in mountain areas may cause significant clustering of body injuries leading to increasing emergency admissions at hospital. We aimed at assessing if surgical safety and efficiency was maintained in this particular context. Methods We selected all emergency admissions of open surgery performed in French hospitals between 2010 and 2012. After identifying mountain areas with increasing volume of surgical stays during winter, we considered seasonal variations in surgical outcomes using a difference-in-differences study design. We computed multilevel regressions to evaluate whether significant increase in emergency cases had an effect on surgical mortality, complications and length of stay. Clustering effect of patients within hospitals was integrated in analysis and surgical outcomes were adjusted for both patient and hospital characteristics. Results A total of 381 hospitals had 559,052 inpatient stays related to emergency open surgery over 3 years. Compared to other geographical areas, a significant peak of activity was noted during winter in mountainous hospitals (Alps, Pyrenees, Vosges), ranging 6-77% volume increase. Peak was mainly explained by tourists’ influx (+124.5%, 4,351/3,496) and increased need for orthopaedic procedures (+36.8%, 4,731/12,873). After controlling for potential confounders, patients did not experience increased risk for postoperative death (ratio of OR 1.01, 95%CI 0.89-1.14, p = 0.891), thromboembolism (0.95, 0.77-1.17, p = 0.621) or sepsis (0.98, 0.85-1.12, p = 0.748). Length of stay was unaltered (1.00, 0.99-1.02, p = 0.716). Conclusion Surgical outcomes are not compromised during winter in French mountain areas despite a substantial influx of major emergencies. PMID:25970625

  16. The effects of phenotypic plasticity on photosynthetic performance in winter rye, winter wheat and Brassica napus.

    PubMed

    Dahal, Keshav; Kane, Khalil; Gadapati, Winona; Webb, Elizabeth; Savitch, Leonid V; Singh, Jasbir; Sharma, Pooja; Sarhan, Fathey; Longstaffe, Fred J; Grodzinski, Bernard; Hüner, Norman P A

    2012-02-01

    The contributions of phenotypic plasticity to photosynthetic performance in winter (cv Musketeer, cv Norstar) and spring (cv SR4A, cv Katepwa) rye (Secale cereale) and wheat (Triticum aestivum) cultivars grown at either 20°C [non-acclimated (NA)] or 5°C [cold acclimated (CA)] were assessed. The 22-40% increase in light-saturated rates of CO₂ assimilation in CA vs NA winter cereals were accounted for by phenotypic plasticity as indicated by the dwarf phenotype and increased specific leaf weight. However, phenotypic plasticity could not account for (1) the differential temperature sensitivity of CO₂ assimilation and photosynthetic electron transport, (2) the increased efficiency and light-saturated rates of photosynthetic electron transport or (3) the decreased light sensitivity of excitation pressure and non-photochemical quenching between NA and NA winter cultivars. Cold acclimation decreased photosynthetic performance of spring relative to winter cultivars. However, the differences in photosynthetic performances between CA winter and spring cultivars were dependent upon the basis on which photosynthetic performance was expressed. Overexpression of BNCBF17 in Brassica napus generally decreased the low temperature sensitivity (Q₁₀) of CO₂ assimilation and photosynthetic electron transport even though the latter had not been exposed to low temperature. Photosynthetic performance in wild type compared to the BNCBF17-overexpressing transgenic B. napus indicated that CBFs/DREBs regulate not only freezing tolerance but also govern plant architecture, leaf anatomy and photosynthetic performance. The apparent positive and negative effects of cold acclimation on photosynthetic performance are discussed in terms of the apparent costs and benefits of phenotypic plasticity, winter survival and reproductive fitness. PMID:21883254

  17. Greater understanding is need of whether warmer and shorter winters associated with climate change could reduce winter mortality

    NASA Astrophysics Data System (ADS)

    Ebi, Kristie L.

    2015-11-01

    In temperate regions, mortality is higher during winter than summer seasons. Assuming this seasonality is associated with ambient temperature, assessments often conclude that climate change will likely reduce winter mortality. However, there has been limited evaluation of the extent to which cold temperatures are actually the proximal cause of winter mortality in temperate regions. Kinney et al (2015 Environ Res. Lett. 10 064016) analyzed multi-decadal data from 39 cities in the US and France and concluded that cold temperatures are not a primary driver of most winter excess mortality. These analyses suggest that increases in heat-related mortality with climate change will unlikely be balanced by reductions in winter mortality, reinforcing the importance of health systems continuing to ensure adequate health protection against cold temperatures even as temperatures warm.

  18. Late Holocene Winter Temperatures in the Eastern Mediterranean and Their Relation to Cultural Changes: The Kocain Cave Record

    NASA Astrophysics Data System (ADS)

    Mert Gokturk, Ozan; Fleitmann, Dominik; Badertscher, Seraina; Cheng, Hai; Edwards, R. Lawrence; Tuysuz, Okan

    2015-04-01

    Based on the δ13C profile of a stalagmite from the Kocain Cave in southern Turkey, we present a new proxy record of winter temperatures for the Eastern Mediterranean covering the last ~5500 years. In this region precisely-dated and highly-resolved paleoclimate records for the cold season are almost non-existent. The comparison of the most recent part of the Kocain record with meteorological observations reveals that stalagmite δ13C values correlate on decadal scale with the amount of snowfall above the cave, which correlates well with average winter temperatures. More negative δ13C values indicate higher drip rates in the cave due to more efficient infiltration during snowmelt above Kocain Cave, during colder winters. Cold periods in the rest of the record coincide with widespread glacier advances, especially with the ones in the Alps during the Bronze Age - Iron Age transition (from ~1000 BC on) and the late Little Ice Age (~1600 to 1850 AD). This further supports the interpretation of δ13C as a temperature proxy. Although winters during the Medieval Climate Anomaly were not continuously warm in the Eastern Mediterranean, winter warmth in the modern era was matched or exceeded several times in the last ~5700 years, especially during the time of Minoan civilization in Crete (~2700 to 1200 BC). Moreover, we provide evidence for the important role of winter cold and drought in the events leading to the unrest in the 16th century Anatolia during the Ottoman rule. Kocain Cave record brings insights into several climatically-induced historical changes in the Eastern Mediterranean, and has the potential to be a key record in a region with a long and vibrant history.

  19. Nutritional condition of Pacific Black Brant wintering at the extremes of their range

    USGS Publications Warehouse

    Mason, D.D.; Barboza, P.S.; Ward, D.H.

    2006-01-01

    Endogenous stores of energy allow birds to survive periods of severe weather and food shortage during winter. We documented changes in lipid, protein, moisture, and ash in body tissues of adult female Pacific Black Brant (Branta bernicla nigricans) and modeled the energetic costs of wintering. Birds were collected at the extremes of their winter range, in Alaska and Baja California, Mexico. Body lipids decreased over winter for birds in Alaska but increased for those in Baja California. Conversely, body protein increased over winter for Brant in Alaska and remained stable for birds in Baja California. Lipid stores likely fuel migration for Brant wintering in Baja California and ensure winter survival for those in Alaska. Increases in body protein may support earlier reproduction for Brant in Alaska. Predicted energy demands were similar between sites during late winter but avenues of expenditure were different. Birds in Baja California spent more energy on lipid synthesis while those in Alaska incurred higher thermoregulatory costs. Estimated daily intake rates of eelgrass were similar between sites in early winter; however, feeding time was more constrained in Alaska because of high tides and short photoperiods. Despite differences in energetic costs and foraging time, Brant wintering at both sites appeared to be in good condition. We suggest that wintering in Alaska may be more advantageous than long-distance migration if winter survival is similar between sites and constraints on foraging time do not impair body condition. ?? The Cooper Ornithological Society 2006.

  20. Winter thunderstorms in central Europe in the past and the present

    NASA Astrophysics Data System (ADS)

    Munzar, Jan; Franc, Marek

    Thunderstorms in the territories of the Czech Republic and neighbouring countries are almost exclusively the only phenomena occurring in the warm season. In the cold half of the year, from October to March, an average incidence of thunderstorms is only 2%, with the least occurrence being recorded in January. Yet, winter thunderstorms are dangerous particularly for air traffic because during them, the cloud base is rapidly falling down and visibility is suddenly worsening due to heavy snowfall. Notwithstanding these facts, the issue of their occurrence in the central European space has been paid little attention so far. Long years of study into historical weather extremes in the territory of the Czech Republic revealed over 10 chronicle entries on the occurrence of winter thunderstorms in the period between November and February from the 16th to the beginning of the 20th centuries. The irregular phenomenon was even devoted three occasional prints in central Europe in the second half of the 16th century, two of which were issued in Germany. Fires caused by winter thunderstorms were no sporadic cases. The occurrence of thunderstorms in winter was apparently associated with the passage of pronounced cold fronts. This can be documented on cases from the end of December 1555 when heavy thunderstorms and consequent fires were recorded within a short period of time in Holland, Germany and in Czech lands. It is assumed that the situation in 1627 was similar when a winter thunderstorm was recorded in Prague and in Holešov, southeastern Moravia on 28 December. In February 1581, a thunderstorm in Prague became one of three unusual events publicized by the local occasional newspaper. The beginning of modern studies into winter thunderstorms dates back to the 1960s with the use of lightning flash counters and later also with the use of systems for large-scale lightning flash detection and localization. However, more comprehensive meteorological and climatological assessments of

  1. Winter Weather Frequently Asked Questions

    MedlinePlus

    ... Planning Information on Specific Types of Emergencies Winter Weather Frequently Asked Questions Language: English Español (Spanish) Recommend ... I do if I get stranded in cold weather? Tie a brightly colored cloth to the antenna ...

  2. The Challenge of Winter Backpacking.

    ERIC Educational Resources Information Center

    Cavanaugh, Michael; Mapes, Alan

    1981-01-01

    Tips and techniques for safe and enjoyable winter backpacking are offered. Topics covered include cross county skis, snowshoes, clothing, footwear, shelter, sleeping bags, food, hypothermia prevention, as well as general rules and requirements. (CO)

  3. Interview with Wallace D. Winters.

    PubMed

    Winters, Wallace D

    2002-01-01

    Wallace Winters exemplifies the model of the basic scientist/clinical toxicologist. His extensive research interests have led to a better understanding of central nervous system excitation and depression, and have included pioneering studies on the neuropharmacology of gammahydroxy butyrate that date back to the 1960s. Dr. Winters was born in New York, NY on June 20, 1929. He received his undergraduate degree at George Washington University, his Ph.D. in Pharmacology/Toxicology at the University of Wisconsin, and his M.D. at the Medical College of Wisconsin. From 1959 to 1962 Dr. Winters pursued postdoctoral studies at the Brain Research Institute at University of California, Los Angeles where he remained on the faculty rising to full Professor. In 1971, Dr. Winters relocated to University of California at Davis where he served as a Professor of Pharmacology/Toxicology for the next 20 years. During this time, Dr. Winters founded the University of California Davis Poison Control Center in Sacramento in 1977 and served as its first medical director until 1983. From 1979 to 1984 he served on the American Academy of Clinical Toxicology Board of Trustees. After retiring from University of California, Davis, Dr. Winters worked as a Medical Officer for the U.S. Food and Drug Administration from 1991 to 1997, and continues to serve as a consultant and medical expert in clinical pharmacology and toxicology. PMID:12126180

  4. Heading for Next Winter Haven

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Approaching its 47th month of a Mars surface mission originally planned to last three months, NASA's Spirit rover was also approaching the northern edge of a low plateau called 'Home Plate.' The rover's operators selected an area with north-facing slope there as a destination where Spirit would have its best chance of surviving low-solar-energy conditions of oncoming Martian winter.

    The yellow line on this map of the Home Plate area indicates Spirit's route from early February 2006, entering the mapped area from the north (top), to late November 2007, on the western edge of the bright-toned Home Plate plateau. The map covers an area about 160 meters (525 feet) across from west to east. Labels indicate the area intended for Spirit to spend many months spanning the rover's third Martian winter, the site where it spent about seven months (April to November 2006) spanning its second winter, and the site where it lost use of the drive motor for one of its six wheels.

    A north-facing slope helps Spirit maximizes electric output from its solar panels during winter months because Spirit is in the southern hemisphere of Mars, so the sun appears only in the northern sky during winter. For the third winter, which will reach its minimum solar-energy days in early June 2008, Spirit faces the challenge of having more dust on its solar panels than it had during its second winter.

    The base image for this map is a portion of a color image taken on Jan. 9, 2007, by the High Resolution Imaging Science Experiment camera on NASA's Mars Reconnaissance Orbiter.

  5. [Ecological benefits of planting winter rapeseed in western China].

    PubMed

    Wang, Xue-fang; Sun, Wan-cang; Li, Fang; Kang, Yan-li; Pu, Yuan-yuan; Liu, Hong-xia; Zeng, Chao-wu; Fan, Chong-xiu

    2009-03-01

    To evaluate the ecological benefits of popularizing winter rapeseed planting in western China, a wind tunnel simulation test was conducted with four kinds of farmland surface, i.e., winter rapeseed, winter wheat, wheat stubble, and bare field just after spring sowing, collected from west Gansu in April. The results showed that winter rapeseed surface had a roughness of 4.08 cm and a threshold wind velocity as high as 14 m x s(-1), being more effective in blown sand control than the other three surfaces. Under the same experimental conditions, the wind erosion modulus and sand transportation rate of winter rapeseed surface were only 4.1% and 485% of those of the bare field just after spring sowing, and the losses of soil organic matter, alkali-hydrolyzed N, available P and K, catalase, urease, alkaline phosphatase, invertase, and microbes of winter rapeseed surface due to wind erosion were only 1.4%, 5.1%, 1.6%, 2.7%, 9.7%, 3.6%, 6.3%, 6.7% and 1.5% of those of the bare field, respectively. It was suggested that popularizing winter rapeseed planting in west China could control wind erosion, retain soil water and nutrients, increase multicropping index, and improve economic benefits of farmland. In addition, it could benefit the regional desertification control and ecological environment improvement. PMID:19637605

  6. Two years with extreme and little snowfall: effects on energy partitioning and surface energy exchange in a high-Arctic tundra ecosystem

    NASA Astrophysics Data System (ADS)

    Stiegler, Christian; Lund, Magnus; Røjle Christensen, Torben; Mastepanov, Mikhail; Lindroth, Anders

    2016-07-01

    Snow cover is one of the key factors controlling Arctic ecosystem functioning and productivity. In this study we assess the impact of strong variability in snow accumulation during 2 subsequent years (2013-2014) on the land-atmosphere interactions and surface energy exchange in two high-Arctic tundra ecosystems (wet fen and dry heath) in Zackenberg, Northeast Greenland. We observed that record-low snow cover during the winter 2012/2013 resulted in a strong response of the heath ecosystem towards low evaporative capacity and substantial surface heat loss by sensible heat fluxes (H) during the subsequent snowmelt period and growing season. Above-average snow accumulation during the winter 2013/2014 promoted summertime ground heat fluxes (G) and latent heat fluxes (LE) at the cost of H. At the fen ecosystem a more muted response of LE, H and G was observed in response to the variability in snow accumulation. Overall, the differences in flux partitioning and in the length of the snowmelt periods and growing seasons during the 2 years had a strong impact on the total accumulation of the surface energy balance components. We suggest that in a changing climate with higher temperature and more precipitation the surface energy balance of this high-Arctic tundra ecosystem may experience a further increase in the variability of energy accumulation, partitioning and redistribution.

  7. Disturbance to wintering western snowy plovers

    USGS Publications Warehouse

    Lafferty, K.D.

    2001-01-01

    In order to better understand the nature of disturbances to wintering snowy plovers, I observed snowy plovers and activities that might disturb them at a beach near Devereux Slough in Santa Barbara, California, USA. Disturbance (activity that caused plovers to move or fly) to wintering populations of threatened western snowy plovers was 16 times higher at a public beach than at protected beaches. Wintering plovers reacted to disturbance at half the distance (???40 m) as has been reported for breeding snowy plovers (???80 m). Humans, dogs, crows and other birds were the main sources of disturbance on the public beach, and each snowy plover was disturbed, on average, once every 27 weekend min and once every 43 weekday min. Dogs off leash were a disproportionate source of disturbance. Plovers were more likely to fly from dogs, horses and crows than from humans and other shorebirds. Plovers were less abundant near trail heads. Over short time scales, plovers did not acclimate to or successfully find refuge from disturbance. Feeding rates declined with increased human activity. I used data from these observations to parameterize a model that predicted rates of disturbance given various management actions. The model found that prohibiting dogs and a 30 m buffer zone surrounding a 400 m stretch of beach provided the most protection for plovers for the least amount of impact to beach recreation.

  8. Nuclear winter attracts additional scrutiny

    SciTech Connect

    Smith, R.J.

    1984-07-06

    Prodded by the Natural Resources Defense Council, Congress has asked the Pentagon to provide what amounts to an environmental impact statement on the potential for nuclear weapons explosions to create enough soot and dust to cause a nuclear winter. The request has implications for arms control and civil defense as well as for weapons procurement and deployment. Little attention was given to the atmospheric and climatic effects of nuclear war until the nuclear winter concept was introduced in October of 1983. Only the Navy and the DOE took steps to follow up until pressure was put on Congress and the Pentagon for further study. Pentagon criticism of the nuclear winter presentation argues that the scenario assumptions that cities will be targeted and that a conflict will involve 5000-6500 megatons are incorrect.

  9. Temporal trends of perfluoroalkyl substances (PFAS) in eggs of coastal and offshore birds: Increasing PFAS levels associated with offshore bird species breeding on the Pacific coast of Canada and wintering near Asia.

    PubMed

    Miller, Aroha; Elliott, John E; Elliott, Kyle H; Lee, Sandi; Cyr, Francois

    2015-08-01

    Perfluoroalkyl substances (PFAS) such as perfluoroalkyl carboxylates (PFCAs) and perfluoroalkyl sulfonates (PFSAs) have become virtually ubiquitous throughout the environment, and, based on laboratory studies, have known toxicological consequences. Various national and international voluntary phase-outs and restrictions on these compounds have been implemented over the last 10 to 15 years. In the present study, we examine trends (1990/1991-2010/2011) in aquatic birds (ancient murrelet, Synthliboramphus antiquus [2009 only]; Leach's storm-petrels, Oceanodroma leucorhoa; rhinoceros auklets, Cerorhinca monocerata; double-crested cormorants, Phalacrocorax auritus; and great blue herons, Ardea herodias). The PFCA, PFSA, and stable isotope (δ(15) N and δ(13) C) data collected from these species from the Pacific coast of Canada, ranging over 20 to 30 years, were used to investigate temporal changes in PFAS coupled to dietary changes. Perfluorooctane sulfonic acid (PFOS), the dominant PFSA compound in all 4 species, increased and subsequently decreased in auklet and cormorant eggs in line with the manufacturing phase-out of PFOS and perfluorooctanoic acid (PFOA), but concentrations continuously increased in petrel eggs and remained largely unchanged in heron eggs. Dominant PFCA compounds varied between the offshore and coastal species, with increases seen in the offshore species and little or variable changes seen in the coastal species. Little temporal change was seen in stable isotope values, indicating that diet alone is not driving observed PFAS concentrations. PMID:25989421

  10. Winter Outdoor Education Activities: Snowshoes and Exploring the Winter Environment.

    ERIC Educational Resources Information Center

    Matthews, Bruce E.; And Others

    Designed as a resource base upon which elementary school educators can build outdoor learning experiences, this resource packet contains a basic, multidisciplinary snowshoeing lesson plan, pre- and post-trip suggestions, and suggestions for further winter outdoor study on snowshoes. Specifically, there are narratives and illustrations addressed at…

  11. Winter Storm Zones on Mars

    NASA Technical Reports Server (NTRS)

    Hollingsworth, J. L.; Haberle, R. M.; Barnes, J. R.; Bridger, A. F. C.; Cuzzi, Jeffrey N. (Technical Monitor)

    1995-01-01

    Preferred regions of weather activity in Mars' winter middle latitudes-so called 'storm zones' are found in a general circulation model of Mars' atmospheric circulation. During northern winter, these storm zones occur in middle latitudes in the major planitia (low-relief regions) of the western and eastern hemisphere. In contrast, the highlands of the eastern hemisphere are mostly quiescent. Compared to Earth's storm zones where diabatic heating associated with land-sea thermal contrasts is crucial, orography on Mars is fundamental to the regionalization of weather activity. Future spacecraft missions aimed at assessing Mars' climate and its variability need to include such regions in observation strategies.

  12. Late Holocene expansion of Siberian dwarf pine (Pinus pumila) in Kamchatka in response to increased snow cover as inferred from lacustrine oxygen-isotope records

    NASA Astrophysics Data System (ADS)

    Hammarlund, Dan; Klimaschewski, Andrea; St. Amour, Natalie A.; Andrén, Elinor; Self, Angela E.; Solovieva, Nadia; Andreev, Andrei A.; Barnekow, Lena; Edwards, Thomas W. D.

    2015-11-01

    Holocene records of cellulose-inferred lake-water δ18O were produced from two lake-sediment sequences obtained in central and northern Kamchatka, Russian Far East. The sediment records share similar fluctuations in δ18O during the interval of ca. 5000-800 cal yr BP that correspond (inversely) with changes in K+ content of the GISP2 ice-core record from Greenland, a proxy for the relative strength of the Siberian High, suggesting control by climate-related variability in δ18O of regional precipitation. The dramatic expansion of Siberian dwarf pine (Pinus pumila) in northern and central Kamchatka between ca. 5000 and 4000 cal yr BP, as inferred from pollen records from the same and neighbouring sites, appears to have occurred at a time of progressively declining δ18O of precipitation. This development is interpreted as reflecting a regional cooling trend accompanied by increasing winter snowfall related to gradual intensification of the Siberian High from ca. 5000 to ca. 3000 cal yr BP. A thicker and more long-lasting snow cover can be assumed to have favoured P. pumila by providing a competitive advantage over other boreal and subalpine tree and shrub species in the region during the later part of the Holocene. These results, which are the first of their kind from Kamchatka, provide novel insight into the Holocene vegetational and climatic development in easternmost Asia, as well as long-term atmospheric circulation dynamics in Beringia.

  13. Studless Winter Tires

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Goodyear Tire and Rubber Company developed a material for Johnson Space Center used as parachute shrouds to soft land the Vikings through the tenuous Martian atmosphere and has been adapted to new radial tire five times stronger than steel. Fiber has a chain-like molecular structure that gives it incredible strength in proportion to its weight. Material is expected to increase tread life by 10,000 miles.

  14. Distribution patterns during winter and fidelity to wintering areas of American black ducks

    USGS Publications Warehouse

    Diefenbach, D.R.; Nichols, J.D.; Hines, J.E.

    1988-01-01

    The distribution patterns during winter of American black ducks were compared among age-sex classes using band recivery data. In addition, fidelity to wintering areas was compared between sexes and between coastal and inland wintering sites.

  15. Descriptions of two new and one newly recorded enchytraeid species (Clitellata, Enchytraeidae) from the Ozegahara Mire, a heavy snowfall highmoor in Central Japan.

    PubMed

    Torii, Takaaki

    2015-01-01

    Three species of semi-aquatic freshwater Enchytraeidae of the genera Mesenchytraeus Eisen, 1878, Chamaedrilus Friend, 1913 and Globulidrilus Christensen & Dózsa-Farkas, 2012 are described from stream, wet soil or snow habitats in the Ozegahara Mire, an extensive high moor in heavy snowfall area in central Japan. Among Mesenchytraeus speies, Mesenchytraeus nivalis sp. nov. is distinguished by not having enlarged chaetae and spermathecal diverticula, vas deferens with atrial glands 3 or 4 in number and club-shaped, spermathecal ental duct short, with sperm bundles in the sperm sack. Chamaedrilus ozensis sp. nov. closely resembles C. floridae, but the length of the sperm funnel and character of the coelomocytes are different. Globulidrilus helgei Christensen & Dózsa-Farkas, 2012 is recorded for the first time from Japan. PMID:26623738

  16. Reducing winter injury in blackberries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated the combination of primocane training and cane positioning techniques using a rotatable cross-arm (RCA) trellis system and covering plants in winter to protect buds and canes from freezing temperatures in ‘Apache’, ‘Boysenberry’, ‘Siskiyou’, and ‘Triple Crown’ blackberry. After tying p...

  17. Confounded winter and spring phenoclimatology on large herbivore ranges

    USGS Publications Warehouse

    Christianson, David; Klaver, Robert W.; Middleton, Arthur; Kauffman, Matthew

    2013-01-01

    Annual variation in winter severity and growing season vegetation dynamics appear to influence the demography of temperate herbivores but parsing winter from spring effects requires independent metrics of environmental conditions specific to each season. We tested for independence in annual variation amongst four common metrics used to describe winter severity and early growing season vegetation dynamics across the entire spatial distribution of elk (Cervus elaphus) in Wyoming from 1989 to 2006. Winter conditions and early growing season dynamics were correlated in a specific way. Winters with snow cover that ended early tended to be followed by early, but slow, rises in the normalized difference vegetation index (NDVI), while long winters with extended periods of snow cover were often followed by late and rapid rises in NDVI. Across the 35 elk ranges, 0.4–86.8 % of the variation in the rate of increase in NDVI’s in spring was explained by the date snow cover disappeared from SNOTEL stations. Because phenoclimatological metrics are correlated across seasons and shifting due to climate change, identifying environmental constraints on herbivore fitness, particularly migratory species, is more difficult than previously recognized.

  18. Wintering ecology of adult North American ospreys

    USGS Publications Warehouse

    Washburn, Brian E.; Martell, Mark S.; Bierregaard, Richard O., Jr.; Henny, Charles J.; Dorr, Brian S.; Olexa, Thomas J.

    2014-01-01

    North American Ospreys (Pandion haliaetus) typically migrate long distances to their wintering grounds in the tropics. Beyond the general distribution of their wintering range (i.e., the Caribbean, South America, and Central America), very little is known about the wintering ecology of these birds. We used satellite telemetry to determine the duration of wintering period, to examine the characteristics of wintering areas used by Ospreys, and to quantify space use and activity patterns of wintering Ospreys. Adult Ospreys migrated to wintering sites and exhibited high wintering site fidelity among years. Overall, Ospreys wintered on river systems (50.6%) more than on lakes (19.0%), and use of coastal areas was (30.4%) intermediate. Ospreys remained on their wintering grounds for an average of 154 d for males and 167 d for females. Locations of wintering Ospreys obtained via GPS-capable satellite telemetry suggest these birds move infrequently and their movements are very localized (i.e., 2 and 1.4 km2, respectively. Overall, our findings suggest wintering adult North American Ospreys are very sedentary, demonstrating a pattern of limited daily movements and high fidelity to a few select locations (presumably roosts). We suggest this wintering strategy might be effective for reducing the risk of mortality and maximizing energy conservation.

  19. Winter movement dynamics of Black Brant

    USGS Publications Warehouse

    Lindberg, Mark S.; Ward, David H.; Tibbitts, T. Lee; Roser, John

    2007-01-01

    Although North American geese are managed based on their breeding distributions, the dynamics of those breeding populations may be affected by events that occur during the winter. Birth rates of capital breeding geese may be influenced by wintering conditions, mortality may be influenced by timing of migration and wintering distribution, and immigration and emigration among breeding populations may depend on winter movement and timing of pair formation. We examined factors affecting movements of black brant (Branta bernicla nigricans) among their primary wintering sites in Mexico and southern California, USA, (Mar 1998-Mar 2000) using capture-recapture models. Although brant exhibited high probability (>0.85) of monthly and annual fidelity to the wintering sites we sampled, we observed movements among all wintering sites. Movement probabilities both within and among winters were negatively related to distance between sites. We observed a higher probability both of southward movement between winters (Mar to Dec) and northward movement between months within winters. Between-winter movements were probably most strongly affected by spatial and temporal variation in habitat quality as we saw movement patterns consistent with contrasting environmental conditions (e.g., La Niña and El Niño southern oscillation cycles). Month-to-month movements were related to migration patterns and may also have been affected by differences in habitat conditions among sites. Patterns of winter movements indicate that a network of wintering sites may be necessary for effective conservation of brant.

  20. Weak precipitation, warm winters and springs impact glaciers of south slopes of Mt. Everest (central Himalaya) in the last two decades (1994-2013)

    NASA Astrophysics Data System (ADS)

    Salerno, F.; Guyennon, N.; Thakuri, S.; Viviano, G.; Romano, E.; Vuillermoz, E.; Cristofanelli, P.; Stocchi, P.; Agrillo, G.; Ma, Y.; Tartari, G.

    2014-12-01

    Studies on recent climate trends from the Himalayan range are limited, and even completely absent at high elevation. This contribution specifically explores the southern slopes of Mt. Everest (central Himalaya), analyzing the minimum, maximum, and mean temperature and precipitation time series reconstructed from seven stations located between 2660 and 5600m a.s.l. over the last twenty years (1994-2013). We complete this analysis with data from all the existing ground weather stations located on both sides of the mountain range (Koshi Basin) over the same period. Overall we observe that the main and more significant increase in temperature is concentrated outside of the monsoon period. At higher elevations minimum temperature (0.072 ± 0.011 °C a-1, p < 0.001) increased far more than maximum temperature (0.009 ± 0.012 °C a-1, p > 0.1), while mean temperature increased by 0.044 ± 0.008 °C a-1, p < 0.05. Moreover, we note a substantial precipitation weakening (9.3 ± 1.8mm a-1, p < 0.01 during the monsoon season). The annual rate of decrease at higher elevation is similar to the one at lower altitudes on the southern side of the Koshi Basin, but here the drier conditions of this remote environment make the fractional loss much more consistent (47% during the monsoon period). This study contributes to change the perspective on which climatic driver (temperature vs. precipitation) led mainly the glacier responses in the last twenty years. The main implications are the following: (1) the negative mass balances of glaciers observed in this region can be more ascribed to less accumulation due to weaker precipitation than to an increase of melting processes. (2) The melting processes have only been favored during winter and spring months and close to the glaciers terminus. (3) A decreasing of the probability of snowfall has significantly interested only the glaciers ablation zones (10%, p < 0.05), but the magnitude of this phenomenon is decidedly lower than the

  1. A comparison of winter mercury accumulation at forested and no-canopy sites measured with different snow sampling techniques

    USGS Publications Warehouse

    Nelson, S.J.; Johnson, K.B.; Weathers, K.C.; Loftin, C.S.; Fernandez, I.J.; Kahl, J.S.; Krabbenhoft, D.P.

    2008-01-01

    Atmospheric mercury (Hg) is delivered to ecosystems via rain, snow, cloud/fog, and dry deposition. The importance of snow, especially snow that has passed through the forest canopy (throughfall), in delivering Hg to terrestrial ecosystems has received little attention in the literature. The snowpack is a dynamic system that links atmospheric deposition and ecosystem cycling through deposition and emission of deposited Hg. To examine the magnitude of Hg delivery via snowfall, and to illuminate processes affecting Hg flux to catchments during winter (cold season), Hg in snow in no-canopy areas and under forest canopies measured with four collection methods were compared: (1) Hg in wet precipitation as measured by the Mercury Deposition Network (MDN) for the site in Acadia National Park, Maine, USA, (2) event throughfall (collected after snowfall cessation for accumulations of >8 cm), (3) season-long throughfall collected using the same apparatus for event sampling but deployed for the entire cold season, and (4) snowpack sampling. Estimates (mean ?? SE) of Hg deposition using these methods during the 91-day cold season in 2004-2005 at conifer sites showed that season-long throughfall Hg flux (1.80 ??g/m2) < snowpack Hg (2.38 ?? 0.68 ??g/m2) < event throughfall flux (5.63 ?? 0.38 ??g/m2). Mercury deposition at the MDN site (0.91 ??g/m2) was similar to that measured at other no-canopy sites in the area using the other methods, but was 3.4 times less than was measured under conifer canopies using the event sampling regime. This indicates that snow accumulated under the forest canopy received Hg from the overstory or exhibited less re-emission of Hg deposited in snow relative to open areas. The soil surface of field-scale plots were sprayed with a natural rain water sample that contained an Hg tracer (202Hg) just prior to the first snowfall to explore whether some snowpack Hg might be explained from soil emissions. The appearance of the 202Hg tracer in the snowpack (0

  2. GOES Satellite Movie of 2014 Winter Storms

    NASA Video Gallery

    This new animation of NOAA's GOES-East satellite imagery shows the movement of winter storms from January 1 to March 24 making for a snowier-than-normal winter along the U.S. East coast and Midwest...

  3. Modeling Winter Cereal Grain Canopies for Legume Intercrop Establishment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As energy demands continue to increase and wheat (Triticum aestivum L.) prices remain high, more North Central U.S. corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] producers may convert some production acres to wheat. Including a winter cereal grain in the rotation increases the opportunity ...

  4. Increasing biomass of winter wheat using sorghum biochars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fertility of highly weathered Ultisols in the southeastern Coastal Plain region of United States is low. In this region, intensive crop production depletes soil nutrients and reduces soil organic carbon (C). Application of crop residues in agricultural systems is an important factor in the contr...

  5. Winter cover crops influence Amaranthus palmeri establishment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Winter cover crops were evaluated for their effect on Palmer amaranth (PA) suppression in cotton production. Cover crops examined included rye and four winter legumes: narrow-leaf lupine, crimson clover, Austrian winter pea, and cahaba vetch. Each legume was evaluated alone and in a mixture with rye...

  6. Time-variability of Polar Winter Snow Clouds on Mars

    NASA Astrophysics Data System (ADS)

    Hayne, P. O.; Kass, D. M.; Kleinboehl, A.; Schofield, J. T.; McCleese, D. J.

    2015-12-01

    Carbon dioxide snow clouds are known to occur in the polar regions on Mars during the long polar night. Earlier studies have shown that a substantial fraction (up to ~20%) of the seasonal ice caps of Mars can be deposited as CO2 snowfall. The presence of optically thick clouds can also strongly influence the polar energy balance, by scattering thermal radiation emitted by the surface and lower atmosphere. Furthermore, snow deposition is likely to affect the surface morphology and subsequent evolution of the seasonal caps. Therefore, both the spatial distribution and time variability of polar snow clouds are important for understanding their influence on the Martian CO2cycle and climate. However, previous investigations have suffered from relatively coarse time resolution (typically days), coarse or incomplete spatial coverage, or both. Here we report results of a dedicated campaign by the Mars Climate Sounder (MCS) onboard the Mars Reconnaissance Orbiter, to observe polar CO2 clouds with an unprecedented time-resolution within the same spatial region. By scanning the MCS field of view, we acquired observations directly over the north pole for every ~2hr orbit over the course of several days. This was repeated during two separate periods in northern winter. The 2 hr sampling frequency enables the detailed study of cloud evolution. These observations were also compared to a cloud-free, control region just off the pole, which was sampled in the same way. Results from this experiment show that the north polar CO2 clouds are dynamic, and appear to follow a consistent pattern: Beginning with a relatively clear atmosphere, the cloud rapidly grows to ~25 - 30 km altitude in < 2 hr. Then, the altitude of the cloud tops diminishes slowly, reaching near the surface after ~6 - 10 hr. We interpret this slow decay as the precipitation of snow particles, which constrains their size to be ~10 - 100 μm. Also pervasive in this season are water ice clouds, which may provide

  7. Strong Costs and Benefits of Winter Acclimatization in Drosophila melanogaster

    PubMed Central

    Schou, Mads Fristrup; Loeschcke, Volker; Kristensen, Torsten Nygaard

    2015-01-01

    Studies on thermal acclimation in insects are often performed on animals acclimated in the laboratory under conditions that are not ecologically relevant. Costs and benefits of acclimation responses under such conditions may not reflect costs and benefits in natural populations subjected to daily and seasonal temperature fluctuations. Here we estimated costs and benefits in thermal tolerance limits in relation to winter acclimatization of Drosophila melanogaster. We sampled flies from a natural habitat during winter in Denmark (field flies) and compared heat and cold tolerance of these to that of flies collected from the same natural population, but acclimated to 25 °C or 13 °C in the laboratory (laboratory flies). We further obtained thermal performance curves for egg-to-adult viability of field and laboratory (25 °C) flies, to estimate possible cross-generational effects of acclimation. We found much higher cold tolerance and a lowered heat tolerance in field flies compared to laboratory flies reared at 25 °C. Flies reared in the laboratory at 13 °C exhibited the same thermal cost-benefit relations as the winter acclimatized flies. We also found a cost of winter acclimatization in terms of decreased egg-to-adult viability at high temperatures of eggs laid by winter acclimatized flies. Based on our findings we suggest that winter acclimatization in nature can induce strong benefits in terms of increased cold tolerance. These benefits can be reproduced in the laboratory under ecologically relevant rearing and testing conditions, and should be incorporated in species distribution modelling. Winter acclimatization also leads to decreased heat tolerance. This may create a mismatch between acclimation responses and the thermal environment, e.g. if temperatures suddenly increase during spring, under current and expected more variable future climatic conditions. PMID:26075607

  8. 77 FR 7000 - Fisheries of the Northeastern United States; Northeast Multispecies Fishery; Gulf of Maine Winter...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-10

    ...NMFS issues this final emergency rule under the Magnuson- Stevens Fishery Conservation and Management Act (Magnuson-Stevens Act). This action implements new stock status determination criteria for Gulf of Maine (GOM) winter flounder and associated increases in GOM winter flounder catch limits based on the most recent and best available scientific information. This action increases fishing year......

  9. Winter temperature variations over middle and lower reaches of the Yangtze River during the past three centuries

    NASA Astrophysics Data System (ADS)

    Hao, Z.-X.; Zheng, J.-Y.; Ge, Q.-S.; Wang, W.-C.

    2012-01-01

    We present statistically reconstructed annual winter (December-February) mean temperature in the Middle and Lower Reaches of the Yangtze River (24-34° N, east of 108° E) back to 1736. The reconstructions are based on information from snowfall days from Yu-Xue-Fen-Cun archive (one of historical documents proxies) in Qing Dynasty (1644-1911). Those information are calibrated with regional winter temperature series spanning the period 1951 to 2007 period. The gap from 1912 to 1950 is filled using early instrumental observation. With respect to the 1951-2007 climatology, the 18th century was 0.6 °C colder, and the 19th century was 1.0 °C colder. But since the 20th century, climate entered into the warming phase, particular in the last 30 yr, the mean temperature from 1981 to 2007 is 0.25 °C higher than that of climatology, a highest level of the past 300 yr. The uncertainty is existed for the period prior of 1900, and possible causes have been discussed here.

  10. The Impact of Winter Heating on Air Pollution in China

    PubMed Central

    Xiao, Qingyang; Ma, Zongwei; Li, Shenshen; Liu, Yang

    2015-01-01

    Fossil-fuel combustion related winter heating has become a major air quality and public health concern in northern China recently. We analyzed the impact of winter heating on aerosol loadings over China using the MODIS-Aqua Collection 6 aerosol product from 2004–2012. Absolute humidity (AH) and planetary boundary layer height (PBL) -adjusted aerosol optical depth (AOD*) was constructed to reflect ground-level PM2.5 concentrations. GIS analysis, standard statistical tests, and statistical modeling indicate that winter heating is an important factor causing increased PM2.5 levels in more than three-quarters of central and eastern China. The heating season AOD* was more than five times higher as the non-heating season AOD*, and the increase in AOD* in the heating areas was greater than in the non-heating areas. Finally, central heating tend to contribute less to air pollution relative to other means of household heating. PMID:25629878

  11. Physiological responses of Yellowstone bison to winter nutritional deprivation

    USGS Publications Warehouse

    DelGiudice, Glenn D.; Singer, Francis J.; Seal, Ulysses S.; Bowser, Gillian

    1994-01-01

    Because nutrition is critically related to other aspects of bison (Bison bison) ecology, and the winter ranges inhabited by bison in Yellowstone National Park (YNP) are ecologically diverse, it was important to determine if nutritional deprivation differences occurred among winter ranges. We used chemistry profiles of urine suspended in snow to compare nutritional deprivation of bison from January to April 1988 on 4 sampling areas of 3 winter ranges in YNP. Declining (P < 0.001) trends of urinary potassium: creatinine ratios in bison on all 4 sampling areas indicated progressive nutritional deprivation through late March. Concurrent increases (P ≤ 0.001) in mean urea nitrogen: creatinine ratios from late February through late march in 3 of 4 areas suggested that increased net catabolism was occurring. Diminished creatinine ratios of sodium and phosphorus reflected low dietary intake of these minerals throughout winter. Mean values and trends of urinary characteristics indicated nutritional deprivation varied among 3 winter ranges in YNP. Continued physiological monitoring of nutritional deprivation, along with detailed examination of other aspects of the bison's ecology, will provide greater insight into the role of ungulate nutrition in the dynamics of such a complex system and improve management.

  12. Chemical characteristics of haze during summer and winter in Guangzhou

    NASA Astrophysics Data System (ADS)

    Tan, Ji-Hua; Duan, Jing-Chun; Chen, Duo-Hong; Wang, Xin-Hua; Guo, Song-Jun; Bi, Xin-Hui; Sheng, Guo-Ying; He, Ke-Bin; Fu, Jia-Mo

    2009-10-01

    Airborne particles were collected with a 10-stage MOUDI and a PM 10 sampler in Guangzhou, China, during both haze and normal days in the summer of 2002 and 2003, and winter 2002. The characteristics of PAHs, organic carbon, elemental carbon and water-soluble inorganic ions were studied under four periods (summer normal, summer haze, winter normal and winter haze). In this study, secondary pollutants (OC, SO 42-, NO 3- and NH 4+) were the major chemical components and appeared to show a remarkably rapid increase from normal to haze days. The particle mass size distributions were bimodal and dominated by fine particles in haze days. A significantly higher OC/EC ratio was found in haze days (3.2-4.7) compared to normal days (1.8-2.8), indicating secondary organic aerosol formation might be significant during haze days. Correlation analysis between visibility and chemical species showed that the major scattering species were TC (total carbon) and sulfate in normal days and nitrate and TC in haze days, respectively. Simultaneously, correlation analysis between visibility and meteorological factors demonstrated that visibility increased with both temperature and wind speed, while it decreased with relative humidity. Furthermore, the relatively higher value of IcdP/(BghiP + IcdP) and the low value of Cmax, CPI, and BghiP/BeP in winter haze could be due to the growth of motor vehicle usage and energy consumption in winter.

  13. Change in abundance of pacific brant wintering in alaska: evidence of a climate warming effect?

    USGS Publications Warehouse

    Ward, D.H.; Dau, C.P.; Lee, T.; Sedinger, J.S.; Anderson, B.A.; Hines, J.E.

    2009-01-01

    Winter distribution of Pacific Flyway brant (Branta bernicla nigricans) has shifted northward from lowtemperate areas to sub-Arctic areas over the last 42 years. We assessed the winter abundance and distribution of brant in Alaska to evaluate whether climate warming may be contributing to positive trends in the most northern of the wintering populations. Mean surface air temperatures during winter at the end of the Alaska Peninsula increased about 1??C between 1963 and 2004, resulting in a 23% reduction in freezing degree days and a 34% decline in the number of days when ice cover prevents birds from accessing food resources. Trends in the wintering population fluctuated with states of the Pacific Decadal Oscillation, increasing during positive (warm) phases and decreasing during negative (cold) phases, and this correlation provides support for the hypothesis that growth in the wintering population of brant in Alaska is linked to climate warming. The size of the wintering population was negatively correlated with the number of days of strong northwesterly winds in November, which suggests that the occurrence of tailwinds favorable for migration before the onset of winter was a key factor in whether brant migrated from Alaska or remained there during winter. Winter distribution of brant on the Alaska Peninsula was highly variable and influenced by ice cover, particularly at the heavily used Izembek Lagoon. Observations of previously marked brant indicated that the Alaska wintering population was composed primarily of birds originating from Arctic breeding colonies that appear to be growing. Numbers of brant in Alaska during winter will likely increase as temperatures rise and ice cover decreases at high latitudes in response to climate warming. ?? The Arctic Institute of North America.

  14. Scenario-based risk analysis of winter snowstorms in the German lowlands

    NASA Astrophysics Data System (ADS)

    von Wulffen, Anja

    2014-05-01

    The northern German lowlands are not especially known for a high frequency of snowfall events. Nevertheless under certain synoptic conditions Lake-Effect-like phenomena caused by the proximity especially of the Baltic Sea can lead to significantly reinforced snowfall intensities that are often accompanied by rather high wind speeds. This makes for infrequent but potentially disastrous snowstorms in a region less accustomed to snow impacts. One possible consequence of an infrastructure failure cascade resulting from severe and longer-lasting snowstorms is a regional disruption of the food supply chain. In the context of "just-in-time"-logistics and the accompanying decrease of storage capabilities, this poses a significant threat to the population's food security. Within the project NeuENV ("New strategies to ensure sufficient food supply in case of crisis in Germany") a snowstorm in the German lowlands involving widespread disruptions of the transportation infrastructure as well as power failures is therefore used as one model for future food supply chain disruptions. In order to obtain a reliable evaluation of the supply chain and crisis management resilience, a detailed snowstorm scenario is being developed. For this purpose, a database of impact reports of past snowstorm events is assembled and analysed to obtain a comprehensive overview of potential infrastructure impairments and failures. Examples of events analysed in this context include the winter 1978/79 with its disastrous snow drifts that commonly attained heights of 3m to 5m leading to a transportation infrastructure collapse across a wide area, the wet snow event in November 2005 in the Münsterland region that caused power failures for up to 250.000 homes, and more recent snowstorms such as Daisy in January 2010. A catalogue of thresholds for relevant parameters indicating when significant failures can be expected is then compiled through a comparison of impact reports with the detailed meteorological

  15. Effects of Wintering Environment and Parasite–Pathogen Interactions on Honey Bee Colony Loss in North Temperate Regions

    PubMed Central

    Currie, Robert W.

    2016-01-01

    Extreme winter losses of honey bee colonies are a major threat to beekeeping but the combinations of factors underlying colony loss remain debatable. We monitored colonies in two environments (colonies wintered indoors or outdoors) and characterized the effects of two parasitic mites, seven viruses, and Nosema on honey bee colony mortality and population loss over winter. Samples were collected from two locations within hives in fall, mid-winter and spring of 2009/2010. Although fall parasite and pathogen loads were similar in outdoor and indoor-wintered colonies, the outdoor-wintered colonies had greater relative reductions in bee population score over winter. Seasonal patterns in deformed wing virus (DWV), black queen cell virus (BQCV), and Nosema level also differed with the wintering environment. DWV and Nosema levels decreased over winter for indoor-wintered colonies but BQCV did not. Both BQCV and Nosema concentration increased over winter in outdoor-wintered colonies. The mean abundance of Varroa decreased and concentration of Sacbrood virus (SBV), Kashmir bee virus (KBV), and Chronic bee paralysis virus (CBPV) increased over winter but seasonal patterns were not affected by wintering method. For most viruses, either entrance or brood area samples were reasonable predictors of colony virus load but there were significant season*sample location interactions for Nosema and BQCV, indicating that care must be taken when selecting samples from a single location. For Nosema spp., the fall entrance samples were better predictors of future infestation levels than were fall brood area samples. For indoor-wintered colonies, Israeli acute paralysis virus IAPV concentration was negatively correlated with spring population size. For outdoor-wintered hives, spring Varroa abundance and DWV concentration were positively correlated with bee loss and negatively correlated with spring population size. Multivariate analyses for fall collected samples indicated higher DWV was

  16. Effects of Wintering Environment and Parasite-Pathogen Interactions on Honey Bee Colony Loss in North Temperate Regions.

    PubMed

    Desai, Suresh D; Currie, Robert W

    2016-01-01

    Extreme winter losses of honey bee colonies are a major threat to beekeeping but the combinations of factors underlying colony loss remain debatable. We monitored colonies in two environments (colonies wintered indoors or outdoors) and characterized the effects of two parasitic mites, seven viruses, and Nosema on honey bee colony mortality and population loss over winter. Samples were collected from two locations within hives in fall, mid-winter and spring of 2009/2010. Although fall parasite and pathogen loads were similar in outdoor and indoor-wintered colonies, the outdoor-wintered colonies had greater relative reductions in bee population score over winter. Seasonal patterns in deformed wing virus (DWV), black queen cell virus (BQCV), and Nosema level also differed with the wintering environment. DWV and Nosema levels decreased over winter for indoor-wintered colonies but BQCV did not. Both BQCV and Nosema concentration increased over winter in outdoor-wintered colonies. The mean abundance of Varroa decreased and concentration of Sacbrood virus (SBV), Kashmir bee virus (KBV), and Chronic bee paralysis virus (CBPV) increased over winter but seasonal patterns were not affected by wintering method. For most viruses, either entrance or brood area samples were reasonable predictors of colony virus load but there were significant season*sample location interactions for Nosema and BQCV, indicating that care must be taken when selecting samples from a single location. For Nosema spp., the fall entrance samples were better predictors of future infestation levels than were fall brood area samples. For indoor-wintered colonies, Israeli acute paralysis virus IAPV concentration was negatively correlated with spring population size. For outdoor-wintered hives, spring Varroa abundance and DWV concentration were positively correlated with bee loss and negatively correlated with spring population size. Multivariate analyses for fall collected samples indicated higher DWV was

  17. Winter fog is decreasing in the fruit growing region of the Central Valley of California

    NASA Astrophysics Data System (ADS)

    Baldocchi, Dennis; Waller, Eric

    2014-05-01

    The Central Valley of California is home to a variety of fruit and nut trees. These trees account for 95% of the U.S. production, but they need a sufficient amount of winter chill to achieve rest and quiescence for the next season's buds and flowers. In prior work, we reported that the accumulation of winter chill is declining in the Central Valley. We hypothesize that a reduction in winter fog is cooccurring and is contributing to the reduction in winter chill. We examined a 33 year record of satellite remote sensing to develop a fog climatology for the Central Valley. We find that the number of winter fog events, integrated spatially, decreased 46%, on average, over 32 winters, with much year to year variability. Less fog means warmer air and an increase in the energy balance on buds, which amplifies their warming, reducing their chill accumulation more.

  18. Communicating Certainty About Nuclear Winter

    NASA Astrophysics Data System (ADS)

    Robock, A.

    2013-12-01

    I have been spending much of my time in the past several years trying to warn the world about the continuing danger of nuclear weapons, and that the solution is a rapid reduction in the nuclear arsenal. I feel that a scientist who discovers dangers to society has an ethical duty to issue a warning, even if the danger is so scary that it is hard for people to deal with. The debate about nuclear winter in the 1980s helped to end the nuclear arms race, but the planet still has enough nuclear weapons, even after reductions planned for 2017 under the New START treaty, to produce nuclear winter, with temperatures plunging below freezing in the summer in major agricultural regions, threatening the food supply for most of the planet. New research by myself, Brian Toon, Mike Mills, and colleagues over the past six years has found that a nuclear war between any two countries, such as India and Pakistan, using 50 atom bombs each of the size dropped on Hiroshima could produce climate change unprecedented in recorded human history, and a world food crisis because of the agricultural effects. This is much less than 1% of the current global arsenal. Communicating certainty - what we know for sure - has been much more effective than communicating uncertainty. The limited success I have had has come from persistence and serendipity. The first step was to do the science. We have published peer-reviewed articles in major journals, including Science, Nature, Proceedings of the National Academy of Sciences, Journal of Geophysical Research, Atmospheric Chemistry and Physics, Physics Today, and Climatic Change. But policymakers do not read these journals. Through fairly convoluted circumstances, which will be described in this talk, we were able to get papers published in Scientific American and the Bulletin of Atomic Scientists. I have also published several encyclopedia articles on the subject. As a Lead Author of Chapter 8 (Radiative Forcing) of the recently published Fifth Assessment

  19. Winter climate changes over East Asian region under RCP scenarios using East Asian winter monsoon indices

    NASA Astrophysics Data System (ADS)

    Hong, Ja-Young; Ahn, Joong-Bae; Jhun, Jong-Ghap

    2016-03-01

    The changes in the winter climatology and variability of the East Asian winter monsoon (EAWM) for the late 21st century (2070-2099) under the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios are projected in terms of EAWM indices (EAWMIs). Firstly, the capability of the climate models participating in the Coupled Model Intercomparison Project phase 5 (CMIP5) in simulating the boreal winter climatology and the interannual variability of the EAWM for the late 20th century (1971-2000) is examined. Nine of twenty-three climate models are selected based on the pattern correlations with observation and a multi-model ensemble is applied to the nine model data. Three of twelve EAWMIs that show the most significant temporal correlations between the observation and CMIP5 surface air temperatures are utilized. The ensemble CMIP5 is capable of reproducing the overall features of the EAWM in spite of some biases in the region. The negative correlations between the EAWMIs and boreal winter temperature are well reproduced and 3-5 years of the major interannual variation observed in this region are also well simulated according to power spectral analyses of the simulated indices. The fields regressed onto the indices that resemble the composite strong winter monsoon pattern are simulated more or less weakly in CMIP5 compared to the observation. However, the regressed fields of sea level pressure, surface air temperature, 500-hPa geopotential height, and 300-hPa zonal wind are well established with pattern correlations above 0.83 between CMIP5 and observation data. The differences between RCPs and Historical indicate strong warming, which increases with latitude, ranging from 1 to 5 °C under RCP4.5 and from 3 to 7 °C under RCP8.5 in the East Asian region. The anomalous southerly winds generally become stronger, implying weaker EAWMs in both scenarios. These features are also identified with fields regressed onto the indices in RCPs. The future projections reveal

  20. Seasonal Forecasts for Northern Hemisphere Winter 2015/16

    NASA Astrophysics Data System (ADS)

    Ineson, Sarah; Scaife, Adam; Comer, Ruth; Dunstone, Nick; Fereday, David; Folland, Chris; Gordon, Margaret; Karpechko, Alexey; Knight, Jeff; MacLachlan, Craig; Smith, Doug; Walker, Brent

    2016-04-01

    The northern winter of 2015/16 gave rise to the strongest El Niño event since 1997/8. Central and eastern Pacific sea surface temperature anomalies exceeded three degrees and closely resembled the strong El Niño in winter of 1982/3. A second feature of this winter was a strong westerly phase of the Quasi-Biennial Oscillation and very strong winds in the stratospheric polar night jet. At the surface, intense extratropical circulation anomalies occurred in both the North Pacific and North Atlantic that were consistent with known teleconnections to the observed phases of ENSO and the QBO. The North Atlantic Oscillation was very positive in the early winter period (Nov-Dec) and was more blocked in the late winter. Initialised climate predictions were able to capture these signals at seasonal lead times. This case study adds to the evidence that north Atlantic circulation exhibits predictability on seasonal timescales, and in this case we show that even aspects of the detailed pattern and sub-seasonal evolution were predicted, providing warning of increased risk of extreme events such as the intense rainfall which caused extreme flooding in the UK in December.

  1. Daily movements of female mallards wintering in Southwestern Louisiana

    USGS Publications Warehouse

    Link, P.T.; Afton, A.D.; Cox, R.R., Jr.; Davis, B.E.

    2011-01-01

    Understanding daily movements of waterfowl is crucial to management of winter habitats, especially along the Gulf Coast where hunting pressure is high. Radio-telemetry was used to investigate movements of female Mallards (Anas platyrchychos) wintering in southwestern Louisiana. Movement distances were analyzed from 2,455 paired locations (diurnal and nocturnal) of 126 Mallards during winters 2004-2005 and 2005-2006 to assess effects of winter, female age, areas closed (Lacassine National Wildlife Refuge [LAC], Cameron Prairie National Wildlife Refuge [CAM], Amoco Pool [AMOCO] or open to hunting [OPEN]), and habitat type, including all interactions. Movement distances from the various land management categories were not consistent by age, date, or by winter. Flight distances from LAC increased with date, whereas those from CAM and OPEN did not vary significantly by date. Female Mallards moved short distances between diurnal and nocturnal sites (ranging from 3.1 to 15.0 km by land management category), suggesting that they are able to meet their daily energy requirements within a smaller area than Northern Pintails (Anas acuta, hereafter Pintails), and thus minimize transit energy costs.

  2. Winter fuels report. Week ending, October 21, 1994

    SciTech Connect

    Zitomer, M.; Griffith, A.; Zyren, J.

    1994-10-01

    Demand for distillate fuel oil is expected to show a slight decline this winter (October 1, 1994-March 31, 1995) from last, according to the Energy Information Administration`s (EIA) 4th Quarter 1994 Short-Term Energy Outlook (STEO) Mid-World Oil Price Case forecast. EIA projects winter demand to decline one percent to 3.3 million barrels per day, assuming normal weather conditions. The effects of expected moderate growth in the economy and industrial production will likely be offset by much warmer temperatures than those a year ago. EIA projects prices for both residential heating oil and diesel fuel to be moderately higher than prices last winter. Increases are likely, primarily because crude oil prices are expected to be higher than they were a year earlier (Table FE5).

  3. Winter Lake Breezes near the Great Salt Lake

    NASA Astrophysics Data System (ADS)

    Crosman, Erik T.; Horel, John D.

    2016-05-01

    Case studies of lake breezes during wintertime cold air pools in Utah's Salt Lake Valley are examined. While summer breezes originating from the Great Salt Lake are typically deeper, of longer duration, and have higher wind speeds than winter breezes, the rate of inland penetration and cross-frontal temperature differences can be higher during the winter. The characteristics of winter breezes and the forcing mechanisms controlling them (e.g., snow cover, background flow, vertical stability profile, clouds, lake temperature, lake sheltering, and drainage pooling) are more complex and variable than those evident in summer. During the afternoon in the Salt Lake Valley, these lake breezes can lead to elevated pollution levels due to the transport of fine particle pollutants from over the Great Salt Lake, decreased vertical mixing depth, and increased vertical stability.

  4. Evapotranspiration of deficit irrigated sorghum and winter wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Deficit irrigation commonly is used in regions with reduced or limited irrigation capacity to increase water use efficiency (WUE). This research measured winter wheat (Triticum aestivum L.) and sorghum (Sorghum bicolor L. Moench) water use (ET) and yields so WUE could be determined. Two precision ...

  5. Registration of 'NE01481' hard red winter wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'NE01481' (Reg. No. PI 659689) hard red winter wheat (Triticum aestivum L.) was developed cooperatively by the Nebraska Agricultural Experiment Station and the USDA-ARS and released in April, 2010. Nebraska wheat growers, in addition to superior agronomic performance, would like to have increased r...

  6. Small Grain Winter Cover Crops for Corn and Soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Winter cover crops are plants that cover the soil between harvest and planting of summer annual grain crops. While doing this, cover crops perform important environmental functions that include reducing soil erosion, accumulating nutrients, and increasing soil carbon. This educational module provide...

  7. Winter cover crops impact on corn production in semiarid regions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cover crops have been proposed as a technique to increase soil health. This study examined the impact of winter brassica cover crop cocktails grown after wheat (Triticum aestivum) on corn yields; corn yield losses due to water and N stress; soil bacteria to fungi ratios; mycorrhizal markers; and ge...

  8. KPI Graduate Executive Summary Report, Summer 2000-Winter 2001.

    ERIC Educational Resources Information Center

    Sheridan Coll. (Ontario).

    Summarizes findings from the Key Performance Indicator Satisfaction Survey administered by Sheridan College in the summer 2000, fall 2000, and winter 2001 terms. This survey was administered in compliance with the Ontario government's efforts to increase the accountability of the Colleges of Applied Arts and Technology through the measurement of…

  9. Tillage Requirments for integrating winter-annual grazing in peanut production: Plant water status and productivity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of crop rotation systems involving winter-annual grazing can help peanut (Arachis hypogaea L.) producers increase profitability, although winter-annual grazing could result in excessive soil compaction, which can severely limit yields. We conducted a 3-yr field study on a Dothan loamy sand i...

  10. Carbon dynamics and changing winter conditions: a review of current understanding and future research directions

    NASA Astrophysics Data System (ADS)

    Haei, M.; Laudon, H.

    2015-09-01

    Despite the important role of winters for northern ecosystems, it remains the least understood of all the seasons. Here, we summarize existing empirical studies on winter climate and carbon dynamics and highlight some important future research directions. The existing studies include field-scale snow-cover manipulation experiments representing extreme soil climate conditions, laboratory soil incubations studying the influential factors, and time-series of climate and carbon data showing long-term natural variations and existing trends. Most of the field and laboratory experiments indicate an increased soil organic carbon loss due to soil frost. Long-term data demonstrate temporal changes in winter CO2 efflux and its important contribution to the annual fluxes. A number of research priorities to improve our understanding of winter conditions include (i) ecosystem processes in the fall-winter and winter-spring shoulder seasons, (ii) extreme events, (iii) partitioning into organic- and inorganic carbon, (iv) carry-over effects of winter and growing season on each other, (v) long-term cumulative impacts, and (vi) improved winter process modelling. These areas of research would enable an improved understanding of the role of the snow covered period for carbon cycling, and provide a basis for more realistic models that include winter processes.

  11. Winter warming from large volcanic eruptions

    NASA Technical Reports Server (NTRS)

    Robock, Alan; Mao, Jianping

    1992-01-01

    An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows warming over Eurasia and North America and cooling over the Middle East which are significant at the 95-percent level. This pattern is found in the first winter after tropical eruptions, in the first or second winter after midlatitude eruptions, and in the second winter after high latitude eruptions. The effects are independent of the hemisphere of the volcanoes. An enhanced zonal wind driven by heating of the tropical stratosphere by the volcanic aerosols is responsible for the regions of warming, while the cooling is caused by blocking of incoming sunlight.

  12. Winter warming from large volcanic eruptions

    SciTech Connect

    Robock, A.; Mao, J.

    1992-01-01

    An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows warming over Eurasia and North America and cooling over the Middle East which are significant at the 95 percent level. This pattern is found in the first winter after tropical eruptions, in the first or second winter after midlatitude eruptions, and in the second winter after high latitude eruptions. The effects are independent of the hemisphere of the volcanoes. An enhanced zonal wind driven by heating of the tropical stratosphere by the volcanic aerosols is responsible for the regions of warming, while the cooling is caused by blocking of incoming sunlight.

  13. Increased snow facilitates plant invasion in mixedgrass prairie.

    PubMed

    Blumenthlal, D; Chimner, R A; Welker, J M; Morgan, J A

    2008-07-01

    Although global change is known to influence plant invasion, little is known about interactions between altered precipitation and invasion. In the North American mixedgrass prairie, invasive species are often abundant in wet and nitrogen (N)-rich areas, suggesting that predicted changes in precipitation and N deposition could exacerbate invasion. Here, this possibility was tested by seeding six invasive species into experimental plots of mixedgrass prairie treated with a factorial combination of increased snow, summer irrigation, and N addition. Without added snow, seeded invasive species were rarely observed. Snow addition increased average above-ground biomass of Centaurea diffusa from 0.026 to 66 g m(-2), of Gypsophila paniculata from 0.1 to 7.3 g m(-2), and of Linaria dalmatica from 5 to 101 g m(-2). Given added snow, summer irrigation increased the density of G. paniculata, and N addition increased the density and biomass of L. dalmatica. Plant density responses mirrored those of plant biomass, indicating that increases in biomass resulted, in part, from increases in recruitment. In contrast to seeded invasive species, resident species did not respond to snow addition. These results suggest that increases in snowfall or variability of snowfall may exacerbate forb invasion in the mixedgrass prairie. PMID:19086291

  14. Forest tree seedlings may suffer from predicted future winters

    NASA Astrophysics Data System (ADS)

    Domisch, Timo; Repo, Tapani; Martz, Françoise; Rautio, Pasi

    2016-04-01

    Future climate scenarios predict increased precipitation and air temperatures, particularly at high latitudes, and especially so during winter, spring and autumn. However, soil temperatures are more difficult to predict, since they depend strongly on the insulating snow cover. Warm periods during winter can lead to thaw-freeze cycles and flooding, which again can result in the formation of ice layers, affecting soil properties, soil gas concentrations and the survival of tree seedlings. We conducted two laboratory experiments of 20 weeks duration each, simulating winter, spring and early summer, and imposed Scots pine (Pinus sylvestris L.) or downy birch (Betula pubescens Ehrh.) seedlings to four different winter scenarios: (1) ambient snow cover, (2) compressed snow and ice encasement, (3) frozen flood and (4) no snow. We estimated the stress that the seedlings experienced by means of gas exchange, chlorophyll fluorescence and determining above- and belowground biomass and carbohydrate contents, as well as measuring soil oxygen and carbon dioxide concentrations. The seedlings in the snow and compressed snow treatments survived until the end of the experiments, although only those covered with an ambient snow cover showed normal height growth and typical carbohydrate contents. The seedlings in the other treatments showed symptoms of dieback already during early spring and had almost completely died at the end of the experiment. Our results suggest the crucial significance of the protective snow cover, and that a missing soil cover or soil hypoxia and anoxia during winter can be lethal for seedlings, and that respiratory losses and winter desiccation of aboveground organs can further lead to the death of tree seedlings.

  15. Controls on winter ecosystem respiration at mid- and high-latitudes

    NASA Astrophysics Data System (ADS)

    Wang, T.; Ciais, P.; Piao, S.; Ottle, C.; Brender, P.; Maignan, F.; Arain, A.; Gianelle, D.; Gu, L.; Lafleur, P.; Laurila, T.; Margolis, H.; Montagnani, L.; Moors, E.; Nobuko, S.; Vesala, T.; Wohlfahrt, G.; Reichstein, M.; Migliavacca, M.; Ammann, C.; Aubinet, M.; Barr, A.; Bernacchi, C.; Bernhofer, C.; Black, T.; Davis, K.; Dellwik, E.; Dragoni, D.; Don, A.; Flanagan, L.; Foken, T.; Granier, A.; Hadley, J.; Hirata, R.; Hollinger, D.; Kato, T.; Kutsch, W.; Marek, M.; Matamala, R.; Matteucci, G.; Meyers, T.; Monson, R.; Munger, J.; Oechel, W.; Paw U, K. T.; Rebmann, C.; Tuba, Z.; Valentini, R.; Varlagin, A.; Verma, S.

    2010-09-01

    Winter CO2 fluxes represent an important component of the annual carbon budget in northern ecosystems. Understanding winter respiration processes and their responses to climate change is also central to our ability to assess terrestrial carbon cycle and climate feedbacks in the future. The factors influencing the spatial and temporal pattern of winter respiration (RECO) of northern ecosystems are poorly understood. For this reason, we analyzed eddy covariance flux data sets from 57 ecosystem sites ranging from ~35° N to ~70° N. Deciduous forests carry the highest winter RECO ratios (9.7-10.5 g C m-2 d-1), when winter is defined as the period during which air temperature remained below 0 °C. By contrast, wetland ecosystems had the lowest winter RECO (2.1-2.3 g C m-2 d-1). Evergreen needle-leaved forests, grasslands and croplands were characterized by intermediate winter RECO values of 7.4-7.9 g C m-2 d-1, 5.8-6.0 g C m-2 d-1, and 5.2-5.3 g C m-2 d-1, respectively. Cross site analysis showed that winter air or soil temperature, and the seasonal amplitude of the leaf area index inferred from satellite observation, which is a proxy for the amount of litter available for RECO in the subsequent winter, are the two main factors determining spatial pattern of daily mean winter RECO. Together, these two factors can explain 71% (Tair, ΔLAI) or 69% (Tsoil, ΔLAI) of the spatial variance of winter RECO across the 57 sites. The spatial temperature sensitivity of daily winter RECO was determined empirically by fitting an Arrhenius relationship to the data. The activation energy parameter of this relationship was found to decrease at increasing soil temperature at a rate of 83.1 KJ ° C-1 (r = -0.32, p < 0.05), which implies a possible dampening of the increase in winter RECO due to global warming. The interannual variability of winter RECO is better explained by soil temperature than by air temperature, likely due to the insulating effects of snow cover. The increase in

  16. Xanthophyll cycle pigment and antioxidant profiles of winter-red (anthocyanic) and winter-green (acyanic) angiosperm evergreen species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaves of many angiosperm evergreen species turn red during winter, corresponding with synthesis of anthocyanin pigments. The function of winter color change, and why it occurs in some species and not others, is not yet understood. We hypothesized that anthocyanins play a compensatory photoprotect...

  17. Abrupt Decline in the Arctic Winter Sea Ice Cover

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino C.

    2007-01-01

    Maximum ice extents in the Arctic in 2005 and 2006 have been observed to be significantly lower (by about 6%) than the average of those of previous years starting in 1979. Since the winter maxima had been relatively stable with the trend being only about -1.5% per decade (compared to about -10% per decade for the perennial ice area), this is a significant development since signals from greenhouse warming are expected to be most prominent in winter. Negative ice anomalies are shown to be dominant in 2005 and 2006 especially in the Arctic basin and correlated with winds and surface temperature anomalies during the same period. Progressively increasing winter temperatures in the central Arctic starting in 1997 is observed with significantly higher rates of increase in 2005 and 2006. The Atlantic Oscillation (AO) indices correlate weakly with the sea ice and surface temperature anomaly data but may explain the recent shift in the perennial ice cover towards the western region. Results suggest that the trend in winter ice is finally in the process of catching up with that of the summer ice cover.

  18. 33 CFR 100.109 - Winter Harbor Lobster Boat Race, Winter Harbor, ME.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Winter Harbor Lobster Boat Race, Winter Harbor, ME. 100.109 Section 100.109 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF... Lobster Boat Race, Winter Harbor, ME. (a) Regulated area. The regulated area includes all waters of...

  19. Effect of cold wave on winter visibility over eastern China

    NASA Astrophysics Data System (ADS)

    Qu, Wenjun; Wang, Jun; Zhang, Xiaoye; Yang, Zhifeng; Gao, Shanhong

    2015-03-01

    Considerable concern has been raised on the severe wintertime haze episodes over eastern China (ECN) where visibility (Vis) decline in winter is identified from 1973 to 2012 (-0.68 km per 10 years or -26% in 40 years). Based upon the analysis of daily Vis and weather records, cold wave (CW) originating from high latitudes is found to increase Vis by 2.7 km on average because of its relatively stronger wind and drier, cleaner air mass compared with the typical, stable midlatitude air over ECN in winter. However, the lessening frequency of CW occurrence and cold air activity in recent years and the accompanied decrease of surface wind speed (-0.15 m/s per 10 years or -18% in the 40 years) may have amplified the effect of increased anthropogenic emissions on Vis and consequently resulted in more substantial Vis decline. A comparison of Vis trends on the "normal wind" days and on all days in winter implies that the emission increase has contributed to about 79% of the declining Vis trend, while the meteorology change contributed 21%. Furthermore, the diurnal cycle of the boundary layer height is found to have weakened or in some cases disappeared in the winters with less CW, which probably contributed to the long-lasting characteristic of the wintertime low Vis events in this region. Hence, the effect of climate change, such as the decrease of CW occurrence, should be accounted as part of the interpretation for the steady decrease of winter Vis over ECN in the past four decades.

  20. Shifting covariability of North American summer monsoon precipitation with antecedent winter precipitation

    USGS Publications Warehouse

    McCabe, G.J.; Clark, M.P.

    2006-01-01

    Previous research has suggested that a general inverse relation exists between winter precipitation in the southwestern United states (US) and summer monsoon precipitation. In addition, it has been suggested that this inverse relation between winter precipitation and the magnitude of the southwestern US monsoon breaks down under certain climatic conditions that override the regional winter/monsoon precipitation relations. Results from this new study indicate that the winter/monsoon precipitation relations do not break down, but rather shift location through time. The strength of winter/monsoon precipitation relations, as indexed by 20-year moving correlations between winter precipitation and monsoon precipitation, decreased in Arizona after about 1970, but increased in New Mexico. The changes in these correlations appear to be related to an eastward shift in the location of monsoon precipitation in the southwestern US. This eastward shift in monsoon precipitation and the changes in correlations with winter precipitation also appear to be related to an eastward shift in July/August atmospheric circulation over the southwestern US that resulted in increased monsoon precipitation in New Mexico. Results also indicate that decreases in sea-surface temperatures (SSTs) in the central North Pacific Ocean also may be associated with th changes in correlations between winter and monsoon precipitation. Copyright ?? 2006 Royal Meteorological Society.

  1. The Winter Environment. Environmental Education Curriculum.

    ERIC Educational Resources Information Center

    Topeka Public Schools, KS.

    Winter seems to hold more mysteries than any other season. It changes the behavior of wildlife and also brings about drastic changes in plant life. This unit, designed around the following two ideas: (1) to develop an appreciation and understanding of the winter season and (2) to understand how plants and wildlife are affected by the winter…

  2. Stem rust resistance in 'Jagger' winter wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    "Jagger" has been utilized widely as a parent to develop hard red winter wheat varieties throughout the U.S. southern Great Plains. Jagger has resistance to stem rust pathogen race TTTTF, which is virulent to many winter wheat cultivars, yet the genetic basis of this resistance remains unknown. Mark...

  3. Nuclear Winter: Scientists in the Political Arena

    NASA Astrophysics Data System (ADS)

    Badash, Lawrence

    2001-03-01

    The nuclear winter phenomenon is used to illustrate the many paths by which scientific advice reaches decision makers in the United States government. Because the Reagan administration was hostile to the strategic policy that the scientific discovery seemed to demand, the leading proponent of nuclear winter, Carl Sagan, used his formidable talent for popularization to reach a larger audience.

  4. Does cold winter weather produce depressive symptoms?

    NASA Astrophysics Data System (ADS)

    Garvey, Michael J.; Goodes, Mike; Furlong, Candy; Tollefson, Gary D.

    1988-06-01

    To examine whether harsh winter weather is associated with depressive symptoms, 45 healthy subjects from Minnesota were compared to 42 subjects from California near the end of the winter season. No differences in the prevalence of depressive symptoms were found between the two groups.

  5. 36 CFR 1002.19 - Winter activities.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Winter activities. 1002.19 Section 1002.19 Parks, Forests, and Public Property PRESIDIO TRUST RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 1002.19 Winter activities. (a) Skiing, snowshoeing, ice skating, sledding,...

  6. 36 CFR 2.19 - Winter activities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Winter activities. 2.19 Section 2.19 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.19 Winter activities. (a) Skiing, snowshoeing,...

  7. 36 CFR 1002.19 - Winter activities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Winter activities. 1002.19 Section 1002.19 Parks, Forests, and Public Property PRESIDIO TRUST RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 1002.19 Winter activities. (a) Skiing, snowshoeing, ice skating, sledding,...

  8. Animals in Winter. Young Discovery Library Series.

    ERIC Educational Resources Information Center

    de Sairigne, Catherine

    This book is written for children 5 through 10. Part of a series designed to develop their curiosity, fascinate them and educate them, this volume introduces the habits of a variety of animals during the winter. Topics include: (1) surviving during winter, including concepts such as migration, hibernation, and skin color change; (2) changing…

  9. Short winters threaten temperate fish populations

    PubMed Central

    Farmer, Troy M.; Marschall, Elizabeth A.; Dabrowski, Konrad; Ludsin, Stuart A.

    2015-01-01

    Although climate warming is expected to benefit temperate ectotherms by lengthening the summer growing season, declines in reproductive success following short, warm winters may counter such positive effects. Here we present long-term (1973–2010) field patterns for Lake Erie yellow perch, Perca flavescens, which show that failed annual recruitment events followed short, warm winters. Subsequent laboratory experimentation and field investigations revealed how reduced reproductive success following short, warm winters underlie these observed field patterns. Following short winters, females spawn at warmer temperatures and produce smaller eggs that both hatch at lower rates and produce smaller larvae than females exposed to long winters. Our research suggests that continued climate warming can lead to unanticipated, negative effects on temperate fish populations. PMID:26173734

  10. Short winters threaten temperate fish populations

    NASA Astrophysics Data System (ADS)

    Farmer, Troy M.; Marschall, Elizabeth A.; Dabrowski, Konrad; Ludsin, Stuart A.

    2015-07-01

    Although climate warming is expected to benefit temperate ectotherms by lengthening the summer growing season, declines in reproductive success following short, warm winters may counter such positive effects. Here we present long-term (1973-2010) field patterns for Lake Erie yellow perch, Perca flavescens, which show that failed annual recruitment events followed short, warm winters. Subsequent laboratory experimentation and field investigations revealed how reduced reproductive success following short, warm winters underlie these observed field patterns. Following short winters, females spawn at warmer temperatures and produce smaller eggs that both hatch at lower rates and produce smaller larvae than females exposed to long winters. Our research suggests that continued climate warming can lead to unanticipated, negative effects on temperate fish populations.

  11. Mass dynamics of wintering Pacific Black Brant: Body, adipose tissue, organ, and muscle masses vary with location

    USGS Publications Warehouse

    Mason, D.D.; Barboza, P.S.; Ward, D.H.

    2007-01-01

    We compared body size and mass of the whole body, organs, adipose tissue, and muscles of adult Pacific Black Brant (Branta bernicla nigricans (Lawrence, 1846)) collected concurrently in Alaska and Baja California during the fall, winter, and spring of 2002-2003. Head and tarsal lengths of males were similar between sites and slightly larger for females in Alaska than in Baja California. Brant appear to operate under similar physiological bounds, but patterns of nutrient allocation differ between sites. Birds wintering in Alaska lost similar amounts of adipose tissue during early winter as birds in Baja California gained during late winter before migration. Masses of the body, adipose tissue, and flight muscles during mid-winter were similar between sites. Seasonal adipose tissue deposition may, therefore, equally favor winter residency or long-distance migration. Gonad and liver masses increased in late winter for birds in Alaska but not for those in Baja California, suggesting birds wintering in Baja may delay reproductive development in favor of allocating reserves needed for migration. Phenotypic flexibility allows Brant to use widely divergent wintering sites. The wintering location of Brant likely depends more upon changes in environmental conditions and food availability, than upon physiological differences between the two wintering populations. ?? 2007 NRC.

  12. A Pan-arctic Survey about the Meaning of Winter Respiration in Northern High Latitudes

    NASA Astrophysics Data System (ADS)

    Selbmann, A. K.; Natali, S.

    2015-12-01

    The arctic is warming at twice the rate of the rest of the planet, with the greatest warming occurring during the winter months. Despite the cold temperatures during the winter, microbial activity continues and leads to a release of soil carbon during a criticial period when plant uptake has ceased. Due to the warming climate, huge pools of carbon stored in permafrost soils are expected to be released to the atmosphere. To identify the annual carbon balance of arctic ecosystems and potential impacts caused by a rise in temperatures, understanding the magnitude of winter respiration is essential. In order to refine current and future estimates of carbon loss from permafrost ecosystems, we conducted a pan-arctic synthesis of winter respiration from northern high latitude regions. We examined differences in cumulative winter respiration among permafrost zones, biomes, ecosystem types, and effects of measurement method on winter respiration estimates. We also examined effect of air temperature and precipitation (Worldclim database) on rates of winter respiration. The database contained 169 measurement points from 46 study sites located throughout the permafrost zones. We found that 21.6 % of annual respiration is happening during non-growing season, which can shift ecosystems from annual sinks during the growing season to net sources of carbon on an annual basis. Across studies, the average carbon loss during the winter was 66 g CO2-C. There was a strong relationship between mean annual air temperature and winter respiration, and lower respiration in continuous compared to discontinuous permafrost zones and northern areas without permafrost. The present results clarify the contribution of winter respiration to annual carbon balance and show the sensitivity of carbon release to rising temperatures in northern high latitudes. These results suggest that permafrost degradation and increased temperature will lead to a higher release of carbon from the Arctic in wintertime

  13. Winter Precipitation in Southeast China: Interdecadal and Interannual variability

    NASA Astrophysics Data System (ADS)

    Zhang, ling; Zhu, xiuhua; Fraedrich, Klaus; Zhi, xiefei

    2013-04-01

    Interdecadal variability of observed winter (DJF) precipitation in Southeast China (1961 to 2010) is characterized by the first EOF of the three-monthly Standardized Precipitation Index (SPI) subjected to a 9-year running mean, while the differences from the original describe the interannual fluctuations. For both time scales the dominating spatial modes represent similar features involving the East Asian Winter Monsoon (EAWM) and the Arctic Oscillation (AO). Dynamic composite analysis (based on NCEP/NCAR and ERA-40 reanalyses) reveals the following results: (i) Interdecadal SPI-variations show a nonlinear trend from a dryer state in the 1970s via an increase during the 1980s towards stabilization on wetter conditions commencing with the 1990s. The associated large-scale circulation features are derived from composites of the wetter (1988-2002) and dryer (1962-1976) period. Increasing wetness in Southeast China is attributed to a weakened East Asian Winter Monsoon (EAWM) which, due to weaker northerlies along the east coast of China, favors northward transport of warm and humid air from tropical oceans to South China. After the 1980s the reduced EAWM, in turn, is related to low-level warming over high-latitude Eurasia due to stronger Arctic Oscillation (AO) by warmer zonal temperature advection. This demonstrates the role of AO in determining the nonlinear trend observed in winter precipitation over South China. (ii) Interannual variability of winter precipitation in Southeast China is related to EAWM modulated by the East Asian Trough (EAT); a weaker (stronger) EAT than normal will weaken (strengthen) EAWM, leading to abundant (less) precipitation in Southeast China.

  14. Shifting mirrors: adaptive changes in retinal reflections to winter darkness in Arctic reindeer

    PubMed Central

    Stokkan, Karl-Arne; Folkow, Lars; Dukes, Juliet; Neveu, Magella; Hogg, Chris; Siefken, Sandra; Dakin, Steven C.; Jeffery, Glen

    2013-01-01

    Arctic reindeer experience extreme changes in environmental light from continuous summer daylight to continuous winter darkness. Here, we show that they may have a unique mechanism to cope with winter darkness by changing the wavelength reflection from their tapetum lucidum (TL). In summer, it is golden with most light reflected back directly through the retina, whereas in winter it is deep blue with less light reflected out of the eye. The blue reflection in winter is associated with significantly increased retinal sensitivity compared with summer animals. The wavelength of reflection depends on TL collagen spacing, with reduced spacing resulting in shorter wavelengths, which we confirmed in summer and winter animals. Winter animals have significantly increased intra-ocular pressure, probably produced by permanent pupil dilation blocking ocular drainage. This may explain the collagen compression. The resulting shift to a blue reflection may scatter light through photoreceptors rather than directly reflecting it, resulting in elevated retinal sensitivity via increased photon capture. This is, to our knowledge, the first description of a retinal structural adaptation to seasonal changes in environmental light. Increased sensitivity occurs at the cost of reduced acuity, but may be an important adaptation in reindeer to detect moving predators in the dark Arctic winter. PMID:24174115

  15. a Climatology of Extreme Minimum Winter Temperatures in Ohio

    NASA Astrophysics Data System (ADS)

    Edgell, Dennis Joe

    The Extreme Minimum Winter Temperature (EMWT) is the coldest temperature recorded each winter at a given weather station. This variable is a measure of winter temperature stress. Extreme cold influences the geographic distribution of plants, and is a prime control for the production of some valuable fruit crops grown in Ohio. EMWT values are often used to map plant hardiness zones, however the magnitude of EMWT and the date that it occurs has varied widely from year to year. Climatic variables rarely remain constant over time, and the plant hardiness zones could shift significantly if the climate changes and there is a trend towards warmer EMWTs. Plants that have their present geographic ranges limited by cold winter temperatures could increase their spatial extent. Furthermore, EMWT has impacts on human health and has applications for architecture. EMWTs at eighty-nine weather stations in Ohio were analyzed. Summary statistics and return period intervals for critical EMWTs are tabulated and mapped. Return period maps may be more useful for environmental planning than plant hardiness zone maps based on average EMWT, especially in a variable climate. Graphical methods, curve fitting and a probability model for the mean were utilized to examine the long term trend. The EMWT has not warmed during the known climatic record of this variable in Ohio. This study demonstrates the need for more applied climatological studies based on the observed climate record, not obscured by the assumptions of the global warming paradigm.

  16. Antifreeze Proteins in Winter Rye Leaves Form Oligomeric Complexes1

    PubMed Central

    Yu, Xiao-Ming; Griffith, Marilyn

    1999-01-01

    Antifreeze proteins (AFPs) similar to three pathogenesis-related proteins, a glucanase-like protein (GLP), a chitinase-like protein (CLP), and a thaumatin-like protein (TLP), accumulate during cold acclimation in winter rye (Secale cereale) leaves, where they are thought to modify the growth of intercellular ice during freezing. The objective of this study was to characterize the rye AFPs in their native forms, and our results show that these proteins form oligomeric complexes in vivo. Nine proteins were separated by native-polyacrylamide gel electrophoresis from apoplastic extracts of cold-acclimated winter rye leaves. Seven of these proteins exhibited multiple polypeptides when denatured and separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. After isolation of the individual proteins, six were shown by immunoblotting to contain various combinations of GLP, CLP, and TLP in addition to other unidentified proteins. Antisera produced against individual cold-induced winter rye GLP, CLP, and TLP all dramatically inhibited glucanase activity in apoplastic extracts from cold-acclimated winter rye leaves, and each antiserum precipitated all three proteins. These results indicate that each of the polypeptides may be exposed on the surface of the protein complexes. By forming oligomeric complexes, AFPs may form larger surfaces to interact with ice, or they may simply increase the mass of the protein bound to ice. In either case, the complexes of AFPs may inhibit ice growth and recrystallization more effectively than the individual polypeptides. PMID:10198095

  17. Changes in winter warming events in the Nordic Arctic Region

    NASA Astrophysics Data System (ADS)

    Vikhamar-Schuler, Dagrun; Isaksen, Ketil; Haugen, Jan Erik; Bjerke, Jarle Werner; Tømmervik, Hans

    2015-04-01

    In recent years winter warming events are frequently reported from Arctic areas. Extraordinarily warm weather episodes, occasionally combined with intense rainfall, cause severe ecological disturbance and great challenges for Arctic infrastructure. For example, the formation of ground ice due to winter rain or melting prevents reindeer from grazing, leads to vegetation browning, and impacts soil temperatures. The infrastructure may be affected by avalanches and floods resulting from intense snowmelt. The aim of our analysis is to study changes in warm spells during winter in the Nordic Arctic Region, here defined as the regions in Norway, Sweden and Finland north of the Arctic circle (66.5°N), including the Arctic islands Svalbard and Jan Mayen. Within this study area we have selected the longest available high quality observation series with daily temperature and precipitation. For studying future climate we use available regionally downscaled scenarios. We analyse three time periods: 1) the past 50-100 years, 2) the present (last 15 years, 2000-2014) and 3) the future (next 50-100 years). We define an extended winter season (October-April) and further divide it into three subseasons: 1) Early winter (October and November), 2) Mid-winter (December, January and February) and 3) Late-winter (March and April). We identify warm spells using two different classification criteria: a) days with temperature above 0°C (the melting temperature); and b) days with temperature in excess of the 90th percentile of the 1985-2014 temperature for each subseason. Both wet and dry warm spells are analysed. We compare the results for the mainland stations (maritime and inland stations) with the Arctic islands. All stations have very high frequency of warm weather events in the period 1930-1940s and for the last 15 years (2000-2014). For the most recent period the largest increase in number of warm spells are observed at the northernmost stations. We also find a continuation of this

  18. Scorecard on winter weather forecast

    NASA Astrophysics Data System (ADS)

    Richman, Barbara T.

    A comparison of the observed temperatures and precipitation for this past winter (maps on left) with predicted temperatures and precipitation (maps on right) shows that the National Weather Service (NWS) temperature prediction was below par, but that the NWS precipitation forecast was ‘quite good,’ according to Don L. Gilman, chief of the NWS long-range forecast branch. The predictions, issued November 29, 1982 (Eos, December 14, 1982, p. 1211), covered December, January, and February.NWS long-range forecasters had thought that frigid Arctic air would swoop far south to bring below-normal temperatures to the western United States. Instead, an east Pacific trough, which may have been the strongest since 1900, brought a strong influx of air from the west, according to Gilman. The intense, low-pressure anomaly in the east Pacific, with the strong westerly winds, teamed with heavy rains south and southwest of Hawaii and warm equatorial Pacific waters to bring warm, wet air to the western United States. The results (see maps): Throughout most of the country, observed temperatures were above normal (A) or normal (N), while observed precipitation was heavy (H) o r normal (no code). Below-normal temperatures (B) occurred only in a portion of the southcentral U.S. and the Florida Keys. Light precipitation (L) fell over two patches in the northern plains, in the Appalachian region, and along the Maine coast.

  19. A Link Between Reduced Arctic Sea Ice and Cold Winter Extremes over Northern Continents

    NASA Astrophysics Data System (ADS)

    Semenov, V. A.; Petoukhov, V.

    2009-04-01

    The recent overall Northern Hemisphere warming was accompanied by several severe northern continental winters, in particular extremely cold winter 2005/2006 in Europe and northern Asia. Here we show that these cold extremes might be favored by anomalous sea ice reduction in the Barents and Kara Seas in the Eastern Arctic. Atmospheric general circulation model simulations demonstrate that strong anti-cyclonic circulation over the Polar Ocean and easterly advection over northern continents may arise as a response to anomalous atmospheric heating. This brings about a continental-scale winter cooling reaching 1.5˚C, with more than three times increased probability of cold winter extremes. Our results imply that several recent harsh winters do not conflict the global warming picture but rather supplement it, being in agreement with the large-scale atmospheric circulation response to Arctic sea ice reduction.

  20. Sleep in fall/winter seasonal affective disorder: effects of light and changing seasons.

    PubMed

    Anderson, J L; Rosen, L N; Mendelson, W B; Jacobsen, F M; Skwerer, R G; Joseph-Vanderpool, J R; Duncan, C C; Wehr, T A; Rosenthal, N E

    1994-05-01

    Disturbances of sleep are a hallmark of seasonal affective disorders (SAD), as they are of other mood disorders. Fall/winter SAD patients most often report hypersomnia. Among responses of 293 SAD patients on a symptom questionnaire, complaints of winter hypersomnia (80%) greatly exceeded insomnia (10%), hypersomnia plus insomnia (5%), or no sleep difficulty (5%). Increased sleep length in fall/winter is not unique to SAD. Among 1571 individuals across four latitudes surveyed at random from the general population, winter sleep increases of < or = 2 hr/day relative to summer were reported by nearly half. However, hypersomnia had a low correlation (r = 0.29) with the total number of other SAD symptoms that were reported in this sample. Ten SAD patients kept daily sleep logs across 1 yr that showed increases in fall and winter (sleeping most in October; least in May) whose maximum averaged 2.7 hr per day more weekend sleep than in spring and summer. These winter increases might have been somewhat attenuated since most received light therapy during part of the winter. Nocturnal EEG recordings of depressed SAD patients in winter showed decreased sleep efficiency, decreased delta sleep percentage, and increased REM density (but normal REM latency) in comparison with recordings: (1) from themselves in summer; (2) from themselves after > or = 9 days of light therapy; or (3) from age- and gender-matched healthy controls. Thus, the extent of fall/winter oversleeping recorded by our SAD patients did not differ dramatically from that reported by the general population, but sleep complaints of our SAD patients have been accompanied by features of sleep architecture that are different from healthy controls and are reversed by summer or by bright-light therapy. PMID:8064650

  1. Density- and Size-Dependent Winter Mortality and Growth of Late Chaoborus flavicans Larvae

    PubMed Central

    Schröder, Arne

    2013-01-01

    Winter processes such as overwinter survival and growth of individuals can have wide-ranging consequences for population dynamics and communities within and across seasons. In freshwater organisms winter processes have been mainly studied in fish despite that invertebrates also have substantial impacts on lake and pond food webs. One of the major invertebrate consumers in lake and ponds is the planktonic larvae of the dipteran insect Chaoborus spec. However, while much is known about Chaoborus feeding ecology, behaviour and structuring role in food webs, its winter ecology and how it affects its populations are poorly understood. Here size- and density-dependent winter mortality and body growth of late Chaoborus flavicans larvae were quantified over naturally occurring size and density ranges in autumn and under natural winter conditions using two field enclosure experiments. Winter mortality increased with autumn density but decreased with autumn body size while winter growth rates decreased with autumn density and body sizes. There was also a density- and size-independent background mortality component. The proportion of pupae found in spring decreased strongly and exponentially with autumn density. These results may explain the commonly observed univoltine life cycle and multi-annual density fluctuations in northern Chaoborus populations. They further demonstrate the relevance of winter processes and conditions for freshwater invertebrates and ecosystems. PMID:24124517

  2. Incidence of mass movement processes after an historical episode of heavy snowfall in the Asturian Massif (Northern Spain)

    NASA Astrophysics Data System (ADS)

    Garcia-Hernandez, Cristina; Ruiz-Fernández, Jesús; Gallinar, David

    2015-04-01

    as landslides, 5 as rockfalls, 4 as mixed typology of rockfalls with a big amount of mud, and 2 as debris flow. One person died as a consecuence of a rockfall. Thirty out of thirty six events anthropic intervention is proved. It acted as a prior conditioning where the previous topography has been modified (in 29 cases), either as a direct triggering mechanism at least in one landslide episode. The sequence analysis of the events shows that their number and frequency increases with episodes of snow melting during the snowstorm breaks, announcing the highest instabilities on 10th and 11th of March, coinciding with a rainfall peak. However the connection with the rainfall episode seems weak compared with the one than can be settled with the rise of temperatures and the resulting melting intensification. It caused the progressive water saturation of surface formations, that reached a maximum during the second break, triggering 20 events during the 11th of March 1888.

  3. Assessing winter cover crop nutrient uptake efficiency using a water quality simulation model

    NASA Astrophysics Data System (ADS)

    Yeo, I.-Y.; Lee, S.; Sadeghi, A. M.; Beeson, P. C.; Hively, W. D.; McCarty, G. W.; Lang, M. W.

    2013-11-01

    Winter cover crops are an effective conservation management practice with potential to improve water quality. Throughout the Chesapeake Bay Watershed (CBW), which is located in the Mid-Atlantic US, winter cover crop use has been emphasized and federal and state cost-share programs are available to farmers to subsidize the cost of winter cover crop establishment. The objective of this study was to assess the long-term effect of planting winter cover crops at the watershed scale and to identify critical source areas of high nitrate export. A physically-based watershed simulation model, Soil and Water Assessment Tool (SWAT), was calibrated and validated using water quality monitoring data and satellite-based estimates of winter cover crop species performance to simulate hydrological processes and nutrient cycling over the period of 1991-2000. Multiple scenarios were developed to obtain baseline information on nitrate loading without winter cover crops planted and to investigate how nitrate loading could change with different winter cover crop planting scenarios, including different species, planting times, and implementation areas. The results indicate that winter cover crops had a negligible impact on water budget, but significantly reduced nitrate leaching to groundwater and delivery to the waterways. Without winter cover crops, annual nitrate loading was approximately 14 kg ha-1, but it decreased to 4.6-10.1 kg ha-1 with winter cover crops resulting in a reduction rate of 27-67% at the watershed scale. Rye was most effective, with a potential to reduce nitrate leaching by up to 93% with early planting at the field scale. Early planting of winter cover crops (~30 days of additional growing days) was crucial, as it lowered nitrate export by an additional ~2 kg ha-1 when compared to late planting scenarios. The effectiveness of cover cropping increased with increasing extent of winter cover crop implementation. Agricultural fields with well-drained soils and those

  4. Assessing winter cover crop nutrient uptake efficiency using a water quality simulation model

    USGS Publications Warehouse

    Yeo, In-Young; Lee, Sangchui; Sadeghi, Ali M.; Beeson, Peter C.; Hively, W. Dean; McCarty, Greg W.; Lang, Megan W.

    2013-01-01

    Winter cover crops are an effective conservation management practice with potential to improve water quality. Throughout the Chesapeake Bay Watershed (CBW), which is located in the Mid-Atlantic US, winter cover crop use has been emphasized and federal and state cost-share programs are available to farmers to subsidize the cost of winter cover crop establishment. The objective of this study was to assess the long-term effect of planting winter cover crops at the watershed scale and to identify critical source areas of high nitrate export. A physically-based watershed simulation model, Soil and Water Assessment Tool (SWAT), was calibrated and validated using water quality monitoring data and satellite-based estimates of winter cover crop species performance to simulate hydrological processes and nutrient cycling over the period of 1991–2000. Multiple scenarios were developed to obtain baseline information on nitrate loading without winter cover crops planted and to investigate how nitrate loading could change with different winter cover crop planting scenarios, including different species, planting times, and implementation areas. The results indicate that winter cover crops had a negligible impact on water budget, but significantly reduced nitrate leaching to groundwater and delivery to the waterways. Without winter cover crops, annual nitrate loading was approximately 14 kg ha−1, but it decreased to 4.6–10.1 kg ha−1 with winter cover crops resulting in a reduction rate of 27–67% at the watershed scale. Rye was most effective, with a potential to reduce nitrate leaching by up to 93% with early planting at the field scale. Early planting of winter cover crops (~30 days of additional growing days) was crucial, as it lowered nitrate export by an additional ~2 kg ha−1 when compared to late planting scenarios. The effectiveness of cover cropping increased with increasing extent of winter cover crop implementation. Agricultural fields with well-drained soils

  5. Climate warming will not decrease winter mortality

    NASA Astrophysics Data System (ADS)

    Staddon, Philip L.; Montgomery, Hugh E.; Depledge, Michael H.

    2014-03-01

    It is widely assumed by policymakers and health professionals that the harmful health impacts of anthropogenic climate change will be partially offset by a decline in excess winter deaths (EWDs) in temperate countries, as winters warm. Recent UK government reports state that winter warming will decrease EWDs. Over the past few decades, however, the UK and other temperate countries have simultaneously experienced better housing, improved health care, higher incomes and greater awareness of the risks of cold. The link between winter temperatures and EWDs may therefore no longer be as strong as before. Here we report on the key drivers that underlie year-to-year variations in EWDs. We found that the association of year-to-year variation in EWDs with the number of cold days in winter ( <5 °C), evident until the mid 1970s, has disappeared, leaving only the incidence of influenza-like illnesses to explain any of the year-to-year variation in EWDs in the past decade. Although EWDs evidently do exist, winter cold severity no longer predicts the numbers affected. We conclude that no evidence exists that EWDs in England and Wales will fall if winters warm with climate change. These findings have important implications for climate change health adaptation policies.

  6. Climate change in our backyards: the reshuffling of North America's winter bird communities.

    PubMed

    Princé, Karine; Zuckerberg, Benjamin

    2015-02-01

    Much of the recent changes in North American climate have occurred during the winter months, and as result, overwintering birds represent important sentinels of anthropogenic climate change. While there is mounting evidence that bird populations are responding to a warming climate (e.g., poleward shifts) questions remain as to whether these species-specific responses are resulting in community-wide changes. Here, we test the hypothesis that a changing winter climate should favor the formation of winter bird communities dominated by warm-adapted species. To do this, we quantified changes in community composition using a functional index--the Community Temperature Index (CTI)--which measures the balance between low- and high-temperature dwelling species in a community. Using data from Project FeederWatch, an international citizen science program, we quantified spatiotemporal changes in winter bird communities (n = 38 bird species) across eastern North America and tested the influence of changes in winter minimum temperature over a 22-year period. We implemented a jackknife analysis to identify those species most influential in driving changes at the community level and the population dynamics (e.g., extinction or colonization) responsible for these community changes. Since 1990, we found that the winter bird community structure has changed with communities increasingly composed of warm-adapted species. This reshuffling of winter bird communities was strongest in southerly latitudes and driven primarily by local increases in abundance and regional patterns of colonization by southerly birds. CTI tracked patterns of changing winter temperature at different temporal scales ranging from 1 to 35 years. We conclude that a shifting winter climate has provided an opportunity for smaller, southerly distributed species to colonize new regions and promote the formation of unique winter bird assemblages throughout eastern North America. PMID:25322929

  7. Winter feeding, growth and condition of brown trout Salmo trutta in a groundwater-dominated stream

    USGS Publications Warehouse

    French, William E.; Vondracek, Bruce C.; Ferrington, Leonard C., Jr.; Finlay, Jacques C.; Dieterman, Douglas J.

    2014-01-01

    Winter can be a stressful period for stream-dwelling salmonid populations, often resulting in reduced growth and survival. Stream water temperatures have been identified as a primary mechanism driving reductions in fitness during winter. However, groundwater inputs can moderate water temperature and may reduce winter severity. Additionally, seasonal reductions in prey availability may contribute to decreased growth and survival, although few studies have examined food webs supporting salmonids under winter conditions. This study employed diet, stable isotope, and mark-recapture techniques to examine winter (November through March) feeding, growth, and condition of brown troutSalmo trutta in a groundwater-dominated stream (Badger Creek, Minnesota, USA). Growth was greater for fish ≤ 150 mm (mean = 4.1 mg g−1 day−1) than for those 151–276 mm (mean = 1.0 mg g−1 day−1) during the winter season. Overall condition from early winter to late winter did not vary for fish ≤150 mm (mean relative weight (Wr) = 89.5) and increased for those 151–276 mm (mean Wr = 85.8 early and 89.4 late). Although composition varied both temporally and by individual, brown trout diets were dominated by aquatic invertebrates, primarily Amphipods, Dipterans, and Trichopterans. Stable isotope analysis supported the observations of the dominant prey taxa in stomach contents and indicated the winter food web was supported by a combination of allochthonous inputs and aquatic macrophytes. Brown trout in Badger Creek likely benefited from the thermal regime and increased prey abundance present in this groundwater-dominated stream during winter.

  8. Winter ecology of the Arunachal macaque Macaca munzala in Pangchen Valley, western Arunachal Pradesh, northeastern India.

    PubMed

    Mendiratta, Uttara; Kumar, Ajith; Mishra, Charudutt; Sinha, Anindya

    2009-11-01

    The newly described Arunachal macaque Macaca munzala occurs largely in sub-tropical to temperate environments at elevations of c. 1,800-3,000 m in Arunachal Pradesh, northeastern India. We studied its over-wintering strategy by comparing the diet, ranging, and behavior of a troop of 24 individuals during winter and spring (December 2005 to May 2006) through instantaneous scan sampling (3,002 records, 448 scans, 112 hr of observation). We also monitored the phenology of food plants. The macaques spent more time (41-66%) feeding in the winter than in spring (33-51%), whereas time spent moving and resting was greater in spring. The diet composed largely of plants, with animal matter being eaten rarely. The number of plant species in the diet increased from 18 to 25 whereas food types rose from 18 to 36 from winter to spring, respectively. Although only two species formed 75% of the winter diet, seven species comprised this proportion in spring. Availability of fruits and young leaves increased in spring; the troop moved more and utilized a larger part of its range during this time. Seasonal changes in behavior could be explained by the scarcity of food and the costs of thermoregulation in winter. Our study suggests that the Arunachal macaque inhabits a highly seasonal environment and has an over-wintering strategy that includes subsisting on a high-fiber diet by increasing the time spent feeding, and minimizing energy expenditure by reducing the time spent moving. PMID:19655365

  9. The influence of tropical forcing on extreme winter precipitation in the western Himalaya

    NASA Astrophysics Data System (ADS)

    Cannon, Forest; Carvalho, Leila M. V.; Jones, Charles; Hoell, Andrew; Norris, Jesse; Kiladis, George N.; Tahir, Adnan A.

    2016-04-01

    Within the Karakoram and western Himalaya (KH), snowfall from winter westerly disturbances (WD) maintains the region's snowpack and glaciers, which melt seasonally to sustain water resources for downstream populations. WD activity and subsequent precipitation are influenced by global atmospheric variability and tropical-extratropical interactions. On interannual time-scales, El Niño related changes in tropical diabatic heating induce a Rossby wave response over southwest Asia that is linked with enhanced dynamical forcing of WD and available moisture. Consequently, extreme orographic precipitation events are more frequent during El Niño than La Niña or neutral conditions. A similar spatial pattern of tropical diabatic heating is produced by the MJO at intraseasonal scales. In comparison to El Niño, the Rossby wave response to MJO activity is less spatially uniform over southwest Asia and varies on shorter time-scales. This study finds that the MJO's relationship with WD and KH precipitation is more complex than that of ENSO. Phases of the MJO propagation cycle that favor the dynamical enhancement of WD simultaneously suppress available moisture over southwest Asia, and vice versa. As a result, extreme precipitation events in the KH occur with similar frequency in most phases of the MJO, however, there is a transition in the relative importance of dynamical forcing and moisture in WD to orographic precipitation in the KH as the MJO evolves. These findings give insight into the dynamics and predictability of extreme precipitation events in the KH through their relationship with global atmospheric variability, and are an important consideration in evaluating Asia's water resources.

  10. Nutrient content of some winter grouse foods

    USGS Publications Warehouse

    Treichler, R.R.; Stow, R.W.; Nelson, A.L.

    1946-01-01

    Seventeen preferred grouse foods were collected during the late winter and analyzed for nutrient content. The results include moisture, crude protein, ether extract, crude fiber, nitrogenfree extract, ash, calcium, phosphorus, and gross energy content expressed both on moisture free and fresh bases.....The preferred winter foods of grouse are characterized by a high content of dry substance and of nitrogen-free extract......On the basis of nutrient content, the foods examined are well qualified as sources of energy and other essential nutrients required for maintenance of grouse during the winter season.

  11. Explaining unusual winter lightning in Japan

    NASA Astrophysics Data System (ADS)

    Shindo, Takatoshi; Ishii, Masaru; Williams, Earle

    2011-11-01

    Third International Symposium on Winter Lightning; Sapporo, Japan, 15-16 June 2011 Japan's meteorological setting in winter is unusual: It is an island in a relatively warm sea frequently overswept by colder air from Siberia. This sets up appreciable atmospheric instability in the fringe of the land adjacent to the Sea of Japan. Heavy snowstorms overlap the edge of the island and produce extraordinarily energetic lightning flashes that initiate from points on the ground (known as ground-to-cloud (GC) strokes) and wreak havoc on power lines and, more recently, wind turbines. These troublesome and costly conditions set the stage for the third in a series of conferences on winter lightning.

  12. The oceanography of winter leads

    NASA Astrophysics Data System (ADS)

    Morison, J. H.; McPhee, M. G.; Curtin, T. B.; Paulson, C. A.

    1992-07-01

    Leads in pack ice have long been considered important to the thermodynamics of the polar regions. A winter lead affects the ocean around it because it is a density source. As the surface freezes, salt is rejected and forms more dense water which sinks under the lead. This sets up a circulation with freshwater flowing in from the sides near the surface and dense water flowing away from the lead at the base of the mixed layer. If the mixed layer is fully turbulent, this pattern may not occur; rather, the salt rejected at the surface may simply mix into the surface boundary layer. In either event the instability produced at the surface of leads is the primary source of unstable buoyancy flux and, as such, exerts a strong influence on the mixed layer. Here as many as possible of the disparate and almost anecdotal observations of lead oceanography are assembled and combined with theoretical arguments to predict the form and scale of oceanographic disturbances caused by winter leads. The experimental data suggest the velocity disturbances associated with lead convection are about 1-5 cm s-1. These appear as jets near the surface and the base of the mixed layer when ice velocities across the lead are less than about 5 cm s-1. The salinity disturbances are about 0.01 to 0.05 psu. Scaling arguments suggest that the geostrophic currents set up by the lead density disturbances are also of the order of 1-5 cm s-1. The disturbances are most obvious when freezing is rapid and ice velocity is low because the salinity and velocity disturbances in the upper ocean are not smeared out by turbulence. In this vein, lead convection may be characterized at one extreme as free convection in which the density disturbance forces the circulation. At the other extreme, lead convection may be characterized as forced convection in which the density disturbance is mixed rapidly by boundary layer turbulence. The lead number Lo, which is the ratio of the pressure term to the turbulence term in the

  13. An analysis of US propane markets, winter 1996-1997

    SciTech Connect

    1997-06-01

    In late summer 1996, in response to relatively low inventory levels and tight world oil markets, prices for crude oil, natural gas, and products derived from both began to increase rapidly ahead of the winter heating season. Various government and private sector forecasts indicated the potential for supply shortfalls and sharp price increases, especially in the event of unusually severe winter weather. Following a rapid runup in gasoline prices in the spring of 1996, public concerns were mounting about a possibly similar situation in heating fuels, with potentially more serious consequences. In response to these concerns, the Energy Information Administration (EIA) participated in numerous briefings and meetings with Executive Branch officials, Congressional committee members and staff, State Energy Offices, and consumers. EIA instituted a coordinated series of actions to closely monitor the situation and inform the public. This study constitutes one of those actions: an examination of propane supply, demand, and price developments and trends.

  14. The History of Winter and the Global Snowflake Network, Engaging Teachers and Students in Science Field Research in Snow and Ice

    NASA Astrophysics Data System (ADS)

    Bender, K. J.; Wasilewski, P. J.; Gabrys, R. E.

    2006-05-01

    A weeklong Professional development/"Teacher as scientist" Cryosphere science training camp held annually in February in Lake Placid, NY, the History of Winter program (HOW) has been serving teachers in the NASA Goddard Space Flight Center service area since 2000. Currently, HOW participants include university faculty interested in enhancing their pre-service science education programs, in-service teachers and pre-service education students. HOW utilizes a stratified professional development approach to science content mastery and delivery while involving participants in scientific field research. Each year program components and resources are added to HOW to provide continued, sustainable interest in the program and to support participants as they continue their HOW experience. An offshoot of the HOW Program, the Global Snowflake Network (GSN) launched in the winter of 2006 engages an international audience including both formal and informal education groups. The goal is to provide an interactive online data resource in science and education for the characterization of snowfall and related weather systems. The Global Snowflake Network has been accepted as an education outreach proposal for the International Polar Year. Collaborations with other agencies and universities also with IPY-accepted proposals are now underway. HOW and the GSN are endorsed by the NASA Goddard Education Office and many of the Goddard Snow and Ice scientists. Together these programs offer a unique, sustainable, and proven outreach for the Cryosphere research program.

  15. Modulation of Dynamic Heating in the Winter Extratropics Associated with the Cross-Equatorial Hadley Circulation.

    NASA Astrophysics Data System (ADS)

    Hou, Arthur Y.; Molod, Andrea

    1995-08-01

    The hypothesis that the cross-equatorial Hadley circulation can modulate the poleward heat transport in the winter extratropics is investigated using the Goddard Earth Observing System (GEOS-1) GCM for 10 northern winter initial conditions. Three-month forecasts are compared with parallel runs from the same initial conditions but with a slightly perturbed radiative forcing in the Tropics. Analysis of the zonal-mean climates shows that, on timescales longer than a month, a persistent intensification in the winter Hadley circulation is positively correlated with increased dynamic cooling in the winter midlatitudes and warming at the high latitudes through-out the troposphere, signaling an increased beat transport toward the winter pole.While the heating anomaly can undergo significant transient fluctuations in the winter extratropics, the variance of the time-averaged dynamic heating anomaly is dominated by contributions from low zonal wavenumbers (particularly wavenumbers 1 and 2), with minor contributions from wavenumbers 4 and higher, suggesting that the low-frequency planetary-scale waves are the primary vehicle for the increased poleward heat transport, with the synoptic-scale waves assuming a secondary role along the storm tracks.These results support the earlier idealized GCM study by Hou showing that a stronger winter Hadley circulation induced by a latitudinal shift in tropical convection can lead to enhanced upper-level tropical easterlies and a slightly stronger subtropical winter jet attended by increased poleward heat transport in the winter extratropics. Specific examples were also found in which the zonally averaged response is dominated by regional changes (notably over the North Pacific), indicating these relations may hold locally, as suggested by Bjerknes.The implication of this work is that the low-frequency variability in the Hadley circulation associated with persistent tropical rainfall anomalies may play an important role in global climate by

  16. Selenium accumulation in sea ducks wintering at Lake Ontario.

    PubMed

    Schummer, Michael L; Badzinski, Shannon S; Petrie, Scott A; Chen, Yu-Wei; Belzile, Nelson

    2010-04-01

    Numbers of wintering sea ducks, including buffleheads (Bucephala albeola; BUFF), common goldeneyes (Bucephala clangula; COGO), and long-tailed ducks (Clangula hyemalis; LTDU), increased substantially at Lake Ontario after Dreissenid mussels (Dreissena bugensis and D. polymorpha) colonized the Great Lakes. Invertebrates, including Dreissenid mussels, are major diving duck prey items that can transfer some trace elements, such as selenium (Se) to higher trophic levels. Se can be problematic for waterfowl and it often has been detected at elevated levels in organisms using the Great Lakes. There are, however, few data on hepatic Se concentrations in sea ducks, particularly during the winter at Lake Ontario. In this study, we evaluated interspecific differences and temporal trends in hepatic Se concentrations among BUFF (n = 77), COGO (n = 77), and LTDU (n = 79) wintering at Lake Ontario. All three species accumulated Se throughout winter, but COGO did so at a higher rate than did BUFF and LTDU. Overall, Se concentrations were higher in LTDU [mean = 22.7; 95% CI = 20.8-24.8 microg/g dry weight (dw)] than in BUFF ([mean = 12.3; 95% CI = 11.6-13.1 microg/g dw) and COGO ([mean = 12.0; 95% CI = 10.7-3.5 microg/g dw) throughout the winter. Se concentrations were deemed elevated (>33 microg/g dw) in 0%, 5%, and 19% of BUFF, COGO, and LTDU, respectively. Presently there are no data on Se toxicity end points for these species, so it is unclear how acquiring concentrations of these magnitudes affect their short- and long-term health or reproduction. PMID:19653029

  17. Herbivory on shoalgrass by wintering redheads in Texas

    USGS Publications Warehouse

    Mitchell, C.A.; Custer, T.W.; Zwank, P.J.

    1994-01-01

    An estimated 80% of redheads (Aythya americana) winter on the Laguna Madre of south Texas and Mexico and feed almost exclusively on shoalgrass (Halodule wrightii) rhizomes. Shoalgrass abundance has decreased by 60% over the past 30 years, and because the effects of shoalgrass loss on wintering redheads are unknown, we initiated a study to define habitat selection criteria and document the effect of wintering redheads on shoalgrass in the lower Laguna Madre, Texas. Redheads consumed an average of 75% of shoalgrass rhizome biomass at collection sites each winter. When rhizome biomass was grazed to a mean biomass of ltoreq 0.18 g dry mass/core (approximately 10 g dry mass/ml), shoalgrass did not recover to its previous level the following growing season. Thirty-three percent of the sites (10) were grazed below 0.18 g dry mass/core during both years of the study, while 64% (19) were grazed below 0.18 g during 1 or the other of the 2 winters. Ramet number was positively correlated (P lt 0.001, r-2 = 0.54) with rhizome biomass; however, this relationship was influenced by grazing intensity. Heavy grazing reduced the amount of rhizome attached to each ramet compared with ungrazed ramets. Grazing had no effect on root biomass (P = 0.388), rhizome moisture content (P = 0.553), or soil magnesium, phosphorous, and potassium (P = 0.102, 0.499, 0.162, respectively). Redhead presence increased (P = 0.042) soil nitrogen levels. Foraging areas selected by redheads within the lower Laguna Madre had lower (P = 0.026) salinities (24 ppt) than areas not selected (35 ppt). Redheads did not select foraging areas in relation to crude protein levels in rhizomes. Shoalgrass habitat in the Laguna Madre should be protected from further losses and enhanced where possible.

  18. How to Find Insects Weathering the Winter.

    ERIC Educational Resources Information Center

    Brody, Jane

    1979-01-01

    Discusses how and where to find insects and other invertebrates in winter, as well as how to collect samples in order to watch those animals reappear in spring. Includes crickets, honey bees, mosquitoes, house flies, and butterflies and moths. (MA)

  19. Physical characteristics of Eurasian winter temperature variability

    NASA Astrophysics Data System (ADS)

    Kim, Kwang-Yul; Son, Seok-Woo

    2016-04-01

    Despite the on-going global warming, recent winters in Eurasian mid-latitudes were much colder than average. In an attempt to better understand the physical characteristics for cold Eurasian winters, major sources of variability in surface air temperature (SAT) are investigated based on cyclostationary EOF analysis. The two leading modes of SAT variability represent the effect of Arctic amplification (AA) and the Arctic oscillation (AO), respectively. These two modes are distinct in terms of the physical characteristics, including surface energy fluxes and tropospheric circulations, and result in significantly different winter SAT patterns over the Eurasian continent. The AA-related SAT anomalies are dipolar with warm Arctic, centered at the Barents–Kara Seas, and cold East Asia. In contrast, the negative AO-related SAT anomalies are characterized by widespread cold anomalies in Northern Eurasia. Relative importance of the AA and the negative AO contributions to cold Eurasian winters is sensitive to the region of interest.

  20. Winter effects on hydraulic conductivity of compacted clay

    SciTech Connect

    Benson, C.H.; Abichou, T.H.; Bosscher, P.J. . Dept. of Civil and Environmental Engineering); Olson, M.A. )

    1995-01-01

    A field test was conducted to determine if freeze-thaw cycles cause increases in hydraulic conductivity in the field, as has been observed in laboratory tests. A test pad of compacted clay was instrumented for monitoring temperatures and climatic conditions and partially insulated. The measurements indicated that up to 10 cycles of freeze-thaw occurred in the uninsulated portion of the test pad whereas no freezing occurred in the insulated portion. Hydraulic-conductivity tests were conducted before and after winter to determine if changes in hydraulic conductivity occurred as a result of winter exposure. In situ hydraulic-conductivity tests showed that the overall hydraulic conductivity was similar in the insulated and uninsulated portions of the test pad before and after winter. No change in overall hydraulic conductivity occurred in the uninsulated region because the depth of frost penetration was only 30% of the thickness of the test pad. However, tests on block specimens collected from near-surface soil that underwent freezing and thawing increased in hydraulic conductivity by a factor of 50--300. Similar increases in hydraulic conductivity were measured using laboratory freeze-thaw tests.

  1. Development of a Model System to Identify Differences in Spring and Winter Oat

    PubMed Central

    Chawade, Aakash; Lindén, Pernilla; Bräutigam, Marcus; Jonsson, Rickard; Jonsson, Anders; Moritz, Thomas; Olsson, Olof

    2012-01-01

    Our long-term goal is to develop a Swedish winter oat (Avena sativa). To identify molecular differences that correlate with winter hardiness, a winter oat model comprising of both non-hardy spring lines and winter hardy lines is needed. To achieve this, we selected 294 oat breeding lines, originating from various Russian, German, and American winter oat breeding programs and tested them in the field in south- and western Sweden. By assaying for winter survival and agricultural properties during four consecutive seasons, we identified 14 breeding lines of different origins that not only survived the winter but also were agronomically better than the rest. Laboratory tests including electrolytic leakage, controlled crown freezing assay, expression analysis of the AsVrn1 gene and monitoring of flowering time suggested that the American lines had the highest freezing tolerance, although the German lines performed better in the field. Finally, six lines constituting the two most freezing tolerant lines, two intermediate lines and two spring cultivars were chosen to build a winter oat model system. Metabolic profiling of non-acclimated and cold acclimated leaf tissue samples isolated from the six selected lines revealed differential expression patterns of 245 metabolites including several sugars, amino acids, organic acids and 181 hitherto unknown metabolites. The expression patterns of 107 metabolites showed significant interactions with either a cultivar or a time-point. Further identification, characterisation and validation of these metabolites will lead to an increased understanding of the cold acclimation process in oats. Furthermore, by using the winter oat model system, differential sequencing of crown mRNA populations would lead to identification of various biomarkers to facilitate winter oat breeding. PMID:22253782

  2. Drivers of Asian winter monsoon evolution since the Last Glacial Maximum (Invited)

    NASA Astrophysics Data System (ADS)

    Morrill, C.; Li, Y.

    2013-12-01

    The Asian winter monsoon is a major center of activity for global winter climate. Its extensive latitudinal reach, in particular, allows it to act as a bridge between extratropical and tropical climate. New loess and ocean sediment records describe how the winter monsoon has evolved over the last 21 ka, with strong phases during the Last Glacial Maximum (LGM) and Early Holocene, and weakening though the Middle and Late Holocene. Abrupt cold events, such as Heinrich event 1 or the 8.2 ka event, were periods of even more intense winter monsoon circulation. Reasons for this evolution have been proposed, but not yet tested using physically-consistent models of the coupled climate system. The causes are likely multiple, since the winter monsoon was strong during both the Early Holocene and the LGM, though the possible drivers (i.e., orbital forcing, greenhouse gas concentration, and ice sheet extent) were quite different between those two time periods. We test these ideas with a series of equilibrium, sensitivity, and transient simulations using the Community Climate System, version 3, coupled climate model. At LGM, the presence of the Laurentide Ice Sheet was primarily responsible for the stronger winter monsoon circulation. Reduced greenhouse gas concentrations at LGM made only a minor contribution. During the Early Holocene, on the other hand, lower winter insolation than today enhanced the land-ocean temperature contrast and strengthened the monsoon circulation. The remnant Laurentide ice sheet of the Early Holocene did not contribute to the stronger winter monsoon. Expansion of Northern Hemisphere sea ice during abrupt cold events increased the latitudinal temperature gradient and intensified winter winds throughout much of the mid-latitudes. Changes in the mechanisms driving winter monsoon behavior through time can also explain the observed covariance with the tropical summer monsoon.

  3. Near cessation of Eighteen Degree Water renewal in the western North Atlantic in the warm winter of 2011-2012

    NASA Astrophysics Data System (ADS)

    Billheimer, Sam; Talley, Lynne D.

    2013-12-01

    The winter of 2011-2012 was a particularly weak season for the renewal of "Eighteen Degree Water" (EDW), the Subtropical Mode Water of the western North Atlantic, as demonstrated by Argo and repeat hydrography. Weak, late winter buoyancy forcing produced shallower than usual winter mixed layers throughout the subtropical gyre, failing to thoroughly ventilate the underlying mode water, and can likely be attributed to the coinciding high, positive phase of the North Atlantic Oscillation (NAO). The only region where EDW was renewed was in the far northeastern Sargasso Sea where it is understood that the Gulf Stream plays a central role in formation; no EDW formed over the large regions of the gyre where deep winter mixed layers driven by surface buoyancy loss normally create EDW. The present investigation evaluates 2011-2012 winter buoyancy content anomalies, surface buoyancy fluxes, and advection of buoyancy via the Gulf Stream and compares them with the previous seven winters that exhibited more vigorous EDW formation. The weak 2011-2012 formation did not result from increased Gulf Stream heat advection, and was also not driven by preconditioning as the buoyancy content of the region prior to the onset of winter forcing was not unusually high. Rather, the weak formation resulted from climatologically weak surface cooling late in winter. The winter of 2007-2008 also experienced particularly weak EDW formation under similar conditions, including a high NAO and weak late winter surface cooling.

  4. Improving winter leaf area index estimation in coniferous forests and its significance in estimating the land surface albedo

    NASA Astrophysics Data System (ADS)

    Wang, Rong; Chen, Jing M.; Pavlic, Goran; Arain, Altaf

    2016-09-01

    Winter leaf area index (LAI) of evergreen coniferous forests exerts strong control on the interception of snow, snowmelt and energy balance. Simulation of winter LAI and associated winter processes in land surface models is challenging. Retrieving winter LAI from remote sensing data is difficult due to cloud contamination, poor illumination, lower solar elevation and higher radiation reflection by snow background. Underestimated winter LAI in evergreen coniferous forests is one of the major issues limiting the application of current remote sensing LAI products. It has not been fully addressed in past studies in the literature. In this study, we used needle lifespan to correct winter LAI in a remote sensing product developed by the University of Toronto. For the validation purpose, the corrected winter LAI was then used to calculate land surface albedo at five FLUXNET coniferous forests in Canada. The RMSE and bias values for estimated albedo were 0.05 and 0.011, respectively, for all sites. The albedo map over coniferous forests across Canada produced with corrected winter LAI showed much better agreement with the GLASS (Global LAnd Surface Satellites) albedo product than the one produced with uncorrected winter LAI. The results revealed that the corrected winter LAI yielded much greater accuracy in simulating land surface albedo, making the new LAI product an improvement over the original one. Our study will help to increase the usability of remote sensing LAI products in land surface energy budget modeling.

  5. Key areas for wintering North American herons

    USGS Publications Warehouse

    Mikuska, T.; Kushlan, J.A.; Hartley, S.

    1998-01-01

    Nearly all North American heron populations are migratory, but details of where they winter are little known. Locations where North American herons winter were identified using banding recovery data. North American herons winter from Canada through northern South America but especially in eastern North America south of New York, Florida, California, Louisiana, Texas, Mexico and Cuba, these areas accounting for 63% of winter recoveries. We identified regions where recoveries for various species clustered as "key areas." These forty-three areas constitute a network of areas that hold sites that likely are important to wintering North American herons. Within each area, we identify specific sites that are potentially important to wintering herons. The relative importance of each area and site within the network must be evaluated by further on the ground inventory. Because of biases inherent in the available data, these hypothesized key areas are indicative rather than exhaustive. As a first cut, this network of areas can serve to inform further inventory activities and can provide an initial basis to begin planning for the year-round conservation of North American heron populations.

  6. Breeding sites and winter site fidelity of Piping Plovers wintering in The Bahamas, a previously unknown major wintering area

    USGS Publications Warehouse

    Gratto-Trevor, Cheri; Haig, Susan M.; Miller, Mark P.; Mullins, Thomas D.; Maddock, Sidney; Roche, Erin A.; Moore, Predensa

    2016-01-01

    Most of the known wintering areas of Piping Plovers (Charadrius melodus) are along the Atlantic and Gulf coasts of the United States and into Mexico, and in the Caribbean. However, 1066 threatened/endangered Piping Plovers were recently found wintering in The Bahamas, an area not previously known to be important for the species. Although representing about 27% of the birds counted during the 2011 International Piping Plover Winter Census, the location of their breeding site(s) was unknown. Thus, our objectives were to determine the location(s) of their breeding site(s) using molecular markers and by tracking banded individuals, identify spring and fall staging sites, and examine site fidelity and survival. We captured and color-banded 57 birds in January and February 2010 in The Bahamas. Blood samples were also collected for genetic evaluation of the likely subspecies wintering in The Bahamas. Band re-sightings and DNA analysis revealed that at least 95% of the Piping Plovers wintering in The Bahamas originated on the Atlantic coast of the United States and Canada. Re-sightings of birds banded in The Bahamas spanned the breeding distribution of the species along the Atlantic coast from Newfoundland to North Carolina. Site fidelity to breeding and wintering sites was high (88–100%). Spring and fall staging sites were located along the Atlantic coast of the United States, with marked birds concentrating in the Carolinas. Our estimate of true survival for the marked birds was 0.71 (95% CI: 0.61–0.80). Our results indicate that more than one third of the Piping Plover population that breeds along the Atlantic coast winters in The Bahamas. By determining the importance of The Bahamas to the Atlantic subspecies of Piping Plovers, future conservation efforts for these populations can be better focused on where they are most needed.

  7. Evidence of a change in water chemistry in Canada's subarctic associated with enhanced winter streamflow

    NASA Astrophysics Data System (ADS)

    Spence, C.; Kokelj, S. V.; Kokelj, S. A.; McCluskie, M.; Hedstrom, N.

    2015-01-01

    winter streamflow is a characteristic of a nival/pluvial regime that has emerged in parts of the subarctic Canadian Shield because of increasingly common late summer rains. This phenomenon is part of a widespread trend toward higher winter streamflow in watersheds across the circumpolar north. There may be implications for biogeochemical systems as streamflow regimes undergo these types of changes associated with climate warming. Streamflow and geochemical fluxes were observed over 2 years with different winter flow conditions in a subarctic Canadian Shield catchment. Results show that higher wintertime loads of carbon and solutes associated with enhanced winter streamflow were in association with an expansion of contributing areas to run off over what would have existed during typical winter recession. Furthermore, the wet fall conditions that lead to enhanced winter streamflow require water tables close to the topographic surface in highly conductive organic soil layers, which is a similar to the condition during the spring melt. Fall rainfall-runoff leaves an ample volume of water in the lakes that are ubiquitous in this landscape. This water maintains winter streamflow during a time when it traditionally would have ceased. A slowing of biological activity under lake ice increases net mineralization and nitrification rates. This convergence of nitrogen cycling and winter streamflow produced a disproportionate flux of inorganic nitrogen from the study catchment. A conceptual model of how enhanced winter streamflow changes water chemistry in a lake-dominated shield landscape is proposed and may be used as a benchmark to guide hypotheses of process interactions, change in other landscapes, or across scales.

  8. Thermodynamic modelling predicts energetic bottleneck for seabirds wintering in the northwest Atlantic.

    PubMed

    Fort, Jérôme; Porter, Warren P; Grémillet, David

    2009-08-01

    Studying the energetics of marine top predators such as seabirds is essential to understand processes underlying adult winter survival and its impact on population dynamics. Winter survival is believed to be the single most important life-history trait in long-lived species but its determinants are largely unknown. Seabirds are inaccessible during this season, so conventional metabolic studies are extremely challenging and new approaches are needed. This paper describes and uses a state-of-the-art mechanistic model, Niche Mapper, to predict energy expenditure and food requirements of the two main seabird species wintering in the northwest Atlantic. We found that energy demand increased throughout the winter phase in both species. Across this period, mean estimated daily energy requirements were 1306 kJ day(-1) for Brünnich's guillemots (Uria lomvia) and 430 kJ day(-1) for little auks (Alle alle) wintering off Greenland and Newfoundland. Mean estimated daily food requirements were 547 g wet food day(-1) for Brünnich's guillemots, and 289 g wet food day(-1) for little auks. For both species and both wintering sites, our model predicts a sharp increase in energy expenditure between November and December, primarily driven by climatic factors such as air temperature and wind speed. These findings strongly suggest the existence of an energetic bottleneck for North Atlantic seabirds towards the end of the year, a challenging energetic phase which might explain recurrent events of winter mass-mortality, so called 'seabird winter wrecks'. Our study therefore emphasizes the relevance of thermodynamics/biophysical modelling for investigating the energy balance of wintering marine top predators and its interplay with survival and population dynamics in the context of global change. PMID:19617442

  9. Changing number of Canada geese wintering in different regions of the Atlantic Flyway

    USGS Publications Warehouse

    Hestbeck, J.B.

    1998-01-01

    During the past 40 years, profound changes have occurred in the number of Canada geese (Branta canadensis) wintering in different regions of the Atlantic Flyway. To explain the declining number of wintering geese in the Chesapeake and Carolina regions and the increasing number in the mid-Atlantic region from 1984 to 1989, I tested several hypotheses concerning regional differences in production, survival, and movement. The observation of migratory geese neckbanded in northern Quebec and throughout the winter grounds, and the lack of a regional difference in the proportion of young in the harvest, indicated that regional differences in production on the breeding grounds was unlikely to explain the observed changes in mid-winter number. Average annual survival rates were highest for geese in the Chesapeake and lowest for geese in the mid-Atlantic indicating that differential survival between regions did not cause the large changes in mid-winter numbers between regions. Geese were more likely to move to, and remain in, the Chesapeake than any other region. Estimated movement patterns did not match observed changes in mid-winter counts. Consequently, the observed changes in number of wintering geese from 1984 to 1989 could not be explained by my analyses of differential production, survival, or movement. The survival and movement analyses, however, were based largely on data from migratory, northern breeding geese. In the aerial Midwinter Waterfowl Survey, migratory, northern-breeding geese cannot be distinguished from local, southern-breeding geese. The changes in mid-winter numbers may result from declining numbers of migratory, northern-breeding geese wintering in the Chesapeake and Carolinas and increasing numbers of local, southem-breeding geese remaining in the mid-Atlantic.

  10. Do wintering Harlequin Ducks forage nocturnally at high latitudes?

    USGS Publications Warehouse

    Rizzolo, D.J.; Esler, Daniel; Roby, D.D.; Jarvis, R.L.

    2005-01-01

    We monitored radio-tagged Harlequin Ducks (Histrionicus histrionicus) to determine whether nocturnal feeding was part of their foraging strategy during winter in south-central Alaska. Despite attributes of our study site (low ambient temperatures, harsh weather, short day length) and study species (small body size, high daytime foraging rates) that would be expected to favor nocturnal foraging, we found no evidence of nocturnal dive-feeding. Signals from eight radio-tagged Harlequin Ducks never exhibited signal loss due to diving during a total of 780 minutes of nocturnal monitoring. In contrast, the same eight birds exhibited signal loss during 62 ± 7% (SE) of 5-minute diurnal monitoring periods (total of 365 minutes of monitoring). Our results suggest that Harlequin Ducks in south-central Alaska face a stringent time constraint on daytime foraging during midwinter. Harlequin Ducks wintering at high latitudes, therefore, may be particularly sensitive to factors that increase foraging requirements or decrease foraging efficiency.

  11. Summer melt regulates winter glacier flow speeds throughout Alaska

    NASA Astrophysics Data System (ADS)

    Burgess, Evan W.; Larsen, Christopher F.; Forster, Richard R.

    2013-12-01

    how climate change will affect glacier and ice sheet flow speeds remains a large hurdle toward accurate sea level rise forecasting. Increases in surface melt rates are known to accelerate glacier flow in summer, whereas in winter, flow speeds are believed to be relatively invariant. Here we show that wintertime flow speeds on nearly all major glaciers throughout Alaska are not only variable but are inversely related to melt from preceding summers. For each additional meter of summertime melt, we observe an 11% decrease in wintertime velocity on glaciers of all sizes, geometries, climates, and bed types. This dynamic occurs because interannual differences in summertime melt affect how much water is retained in the subglacial system during winter. The ubiquity of the dynamic indicates it occurs globally on glaciers and ice sheets not frozen to their beds and thus constitutes a new mechanism affecting sea level rise projections.

  12. Red spruce decline---Winter injury and air pollutants

    SciTech Connect

    Roberts, T.M. )

    1989-10-01

    There has been a widespread decline in growth of red spruce (Picea rubens Sarg.) since 1960 in the eastern United States. There is evidence that this decline is at least partly attributable to age- and density-related growth patterns, particularly at lower elevations. Mortality has been severe at high elevation sites where similar episodes have occasionally occurred in the last 100 years. At these sites, periods of low growth preceding 1960 were related to periods with warm late summers and cold early winters. Since 1960, this relationship no longer holds, although there is an association with unusual deviations from mean temperatures. There are field reports that one of the main causes of reduced growth and mortality is apical dieback induced by severe winter conditions. Preliminary observations suggest that high elevation red spruce may not be sufficiently hardened to tolerate low autumn temperatures. However, appearance of injury in the spring, association of injury with wind exposure and correlation of provenance susceptibility with cuticular transpiration rates, including the importance of desiccation injury. Sensitivity to both types of winter injury may be increased by air pollutants (particularly ozone and less probably, acid mist or excess nitrogen deposition). Nutrient deficiency (particularly magnesium and to a lesser extent potassium) may also increase cold sensitivity. The nature and extent of these interactions are being actively researched for red spruce. 48 refs.

  13. Relations between winter 700-mb height anomalies and mass balance of South Cascade Glacier, Washington

    SciTech Connect

    McCabe, G.J.; Fountain, A.G.

    1995-12-31

    The yearly net mass balance of South Cascade Glacier, Washington, decreased during the mid-1970`s. Results show that the decrease is primarily caused by a significant decrease in the winter mass balance. The decrease in winter mass balance is caused, in part, by changes in winter mean atmospheric circulation that began during the mid-1970`s. Since the mid-1970`s, there has been an increase in winter mean atmospheric pressure over western Canada and the northern western contiguous US and a decrease in winter mean atmospheric pressure in the eastern North Pacific Ocean centered near the Aleutian islands. These changes in atmospheric circulation indicate a decrease in the movement of storms and moisture from the Pacific Ocean into the western contiguous US. In addition, the increase in atmospheric pressure over western Canada and the northern western contiguous US indicates an increase in subsidence, which results in a warming and drying of the air that further reduces precipitation and also increases the ratio of rain to snow during the cold season. These factors contribute to below-average winter mass balances.

  14. The effect of winter drought on evaporation from a high-elevation wetland

    NASA Astrophysics Data System (ADS)

    Blanken, Peter D.

    2014-07-01

    The surface energy balance of a high-elevation groundwater-fed wetland (High Creek Fen) in central Colorado was measured from 9 June 2000 through 18 January 2005. In agreement with observations and predictions for decreased winter snow cover in the region, the low snow cover in 2001-2002 allowed for an examination of the impact of winter drought on the wetland. During years with an average snowpack, summer evaporation far exceeded precipitation. Despite near-normal summer precipitation following a winter drought, the summertime surface energy balance was affected with decreased latent heat fluxes and increased sensible heat fluxes. The leaf area index and the fraction of photosynthetic radiation absorbed were reduced following the winter drought. A shift in the primary controls on evaporation occurred as the surface's response to vapor pressure deficits and soil moisture increased following the winter drought. The earlier snowmelt coupled with earlier increase in soil temperature and moisture following winter drought did not increase evaporation, since vegetation was not yet developed, and evaporation from soil water was low during the early spring period.

  15. Winter Survival of Individual Honey Bees and Honey Bee Colonies Depends on Level of Varroa destructor Infestation

    PubMed Central

    van Dooremalen, Coby; Gerritsen, Lonne; Cornelissen, Bram; van der Steen, Jozef J. M.; van Langevelde, Frank; Blacquière, Tjeerd

    2012-01-01

    Background Recent elevated winter loss of honey bee colonies is a major concern. The presence of the mite Varroa destructor in colonies places an important pressure on bee health. V. destructor shortens the lifespan of individual bees, while long lifespan during winter is a primary requirement to survive until the next spring. We investigated in two subsequent years the effects of different levels of V. destructor infestation during the transition from short-lived summer bees to long-lived winter bees on the lifespan of individual bees and the survival of bee colonies during winter. Colonies treated earlier in the season to reduce V. destructor infestation during the development of winter bees were expected to have longer bee lifespan and higher colony survival after winter. Methodology/Principal Findings Mite infestation was reduced using acaricide treatments during different months (July, August, September, or not treated). We found that the number of capped brood cells decreased drastically between August and November, while at the same time, the lifespan of the bees (marked cohorts) increased indicating the transition to winter bees. Low V. destructor infestation levels before and during the transition to winter bees resulted in an increase in lifespan of bees and higher colony survival compared to colonies that were not treated and that had higher infestation levels. A variety of stress-related factors could have contributed to the variation in longevity and winter survival that we found between years. Conclusions/Significance This study contributes to theory about the multiple causes for the recent elevated colony losses in honey bees. Our study shows the correlation between long lifespan of winter bees and colony loss in spring. Moreover, we show that colonies treated earlier in the season had reduced V. destructor infestation during the development of winter bees resulting in longer bee lifespan and higher colony survival after winter. PMID:22558421

  16. Charred Forests Increase Snow Albedo Decay: Watershed-Scale Implications of the Postfire Snow Albedo Effect

    NASA Astrophysics Data System (ADS)

    Gleason, K. E.; Nolin, A. W.

    2014-12-01

    Recent work shows that after a high severity forest fire, approximately 60% more solar radiation reaches the snow surface due to the reduction in canopy density. Also, significant amounts of black carbon (BC) particles and larger burned woody debris (BWD) are shed from standing charred trees, which concentrate on the snowpack, darken its surface, and reduce snow albedo by 50% during ablation. The postfire forest environment drives a substantial increase in net shortwave radiation at the snowpack surface, driving earlier and more rapid melt, however hydrologic models do not explicitly incorporate forest fire disturbance effects to snowpack dynamics. In this study we characterized, parameterized, and validated the postfire snow albedo effect: how the deposition and concentration of charred forest debris decreases snow albedo, increases snow albedo decay rates, and drives an earlier date of snow disappearance. For three study sites in the Oregon High Cascade Mountains, a 2-yr old burned forest, a 10-yr burned forest, and a nearby unburned forest, we used a suite of empirical data to characterize the magnitude and duration of the postfire effect to snow albedo decay. For WY 2012, WY2013, and WY2014 we conducted spectral albedo measurements, snow surface sampling, in-situ snow and meteorological monitoring, and snow energy balance modeling. From these data we developed a new parameterization which represents the postfire effect to snow albedo decay as a function of days-since-snowfall. We validated our parameterization using a physically-based, spatially-distributed snow accumulation and melt model, in-situ snow monitoring, net snowpack radiation, and remote sensing data. We modeled snow dynamics across the extent of all burned area in the headwaters of the McKenzie River Basin and validated the watershed-scale implications of the postfire snow albedo effect using in-situ micrometeorological and remote sensing data. This research quantified the watershed scale postfire

  17. Winter and early spring CO2 efflux from tundra communities of northern Alaska

    NASA Astrophysics Data System (ADS)

    Fahnestock, J. T.; Jones, M. H.; Brooks, P. D.; Walker, D. A.; Welker, J. M.

    1998-11-01

    Carbon dioxide concentrations through snow were measured in different arctic tundra communities on the North Slope of Alaska during winter and early spring of 1996. Subnivean CO2 concentrations were always higher than atmospheric CO2. A steady state diffusion model was used to generate conservative estimates of CO2 flux to the atmosphere. The magnitude of CO2 efflux differed with tundra community type, and rates of carbon release increased from March to May. Winter CO2 efflux was highest in riparian and snow bed communities and lowest in dry heath, upland tussock, and wet sedge communities. Snow generally accrues earlier in winter and is deeper in riparian and snow bed communities compared with other tundra communities, which are typically windswept and do not accumulate much snow during the winter. These results support the hypothesis that early and deep snow accumulation may insulate microbial populations from very cold temperatures, allowing sites with earlier snow cover to sustain higher levels of activity throughout winter compared to communities that have later developing snow cover. Extrapolating our estimates of CO2 efflux to the entire snow-covered season indicates that total carbon flux during winter in the Arctic is 13-109 kg CO2-C ha-1, depending on the vegetation community type. Wintertime CO2 flux is a potentially important, yet largely overlooked, part of the annual carbon cycle of tundra, and carbon release during winter should be accounted for in estimates of annual carbon balance in arctic ecosystems.

  18. A metagenomic assessment of winter and summer bacterioplankton from Antarctica Peninsula coastal surface waters

    PubMed Central

    Grzymski, Joseph J; Riesenfeld, Christian S; Williams, Timothy J; Dussaq, Alex M; Ducklow, Hugh; Erickson, Matthew; Cavicchioli, Ricardo; Murray, Alison E

    2012-01-01

    Antarctic surface oceans are well-studied during summer when irradiance levels are high, sea ice is melting and primary productivity is at a maximum. Coincident with this timing, the bacterioplankton respond with significant increases in secondary productivity. Little is known about bacterioplankton in winter when darkness and sea-ice cover inhibit photoautotrophic primary production. We report here an environmental genomic and small subunit ribosomal RNA (SSU rRNA) analysis of winter and summer Antarctic Peninsula coastal seawater bacterioplankton. Intense inter-seasonal differences were reflected through shifts in community composition and functional capacities encoded in winter and summer environmental genomes with significantly higher phylogenetic and functional diversity in winter. In general, inferred metabolisms of summer bacterioplankton were characterized by chemoheterotrophy, photoheterotrophy and aerobic anoxygenic photosynthesis while the winter community included the capacity for bacterial and archaeal chemolithoautotrophy. Chemolithoautotrophic pathways were dominant in winter and were similar to those recently reported in global ‘dark ocean' mesopelagic waters. If chemolithoautotrophy is widespread in the Southern Ocean in winter, this process may be a previously unaccounted carbon sink and may help account for the unexplained anomalies in surface inorganic nitrogen content. PMID:22534611

  19. Changes in the structure of the rhizosphere complex of actinomycetes in the ontogenesis of winter rye

    NASA Astrophysics Data System (ADS)

    Shirokikh, I. G.; Merzaeva, O. V.; Zenova, G. M.

    2006-06-01

    Changes in the taxonomic structure of actinomycetes in the rhizosphere of winter rye ( Secale cereale L.) growing on acid soddy-podzolic soil were studied. During the first stages of ontogenesis of winter rye, the rhizosphere complex of mycelial prokaryotes was characterized by a relatively level generic structure (with respect to the indices of abundance and frequency of particular genera), low values of the species diversity, and low domination frequency of the species from the Streptomyces genus. The numbers and species diversity of the streptomycetes increased during the further growth of the winter rye, so that streptomycetes became a dominant group in the complex of the rhizosphere actinomycetes. According to the two-way ANOVA, the population density of the Micromonospora and the Streptosporangium genera in the rhizosphere was mainly dictated by the winter rye variety, whereas the population density of the streptomycetes depended on the particular stage of the winter rye development. The differences between the actinomycetal complexes characteristic of different varieties of winter rye at the early stages of its development was leveled by the end of the winter rye growth.

  20. Temperature characteristics of winter roost-sites for birds and mammals: tree cavities and anthropogenic alternatives

    NASA Astrophysics Data System (ADS)

    Grüebler, Martin U.; Widmer, Silv; Korner-Nievergelt, Fränzi; Naef-Daenzer, Beat

    2014-07-01

    The microclimate of potential roost-sites is likely to be a crucial determinant in the optimal roost-site selection of endotherms, in particular during the winter season of temperate zones. Available roost-sites for birds and mammals in European high trunk orchards are mainly tree cavities, wood stacks and artificial nest boxes. However, little is known about the microclimatic patterns inside cavities and thermal advantages of using these winter roost-sites. Here, we simultaneously investigate the thermal patterns of winter roost-sites in relation to winter ambient temperature and their insulation capacity. While tree cavities and wood stacks strongly buffered the daily cycle of temperature changes, nest boxes showed low buffering capacity. The buffering effect of tree cavities was stronger at extreme ambient temperatures compared to temperatures around zero. Heat sources inside roosts amplified Δ T (i.e., the difference between inside and outside temperatures), particularly in the closed roosts of nest boxes and tree cavities, and less in the open wood stacks with stronger circulation of air. Positive Δ T due to the installation of a heat source increased in cold ambient temperatures. These results suggest that orchard habitats in winter show a spatiotemporal mosaic of sites providing different thermal benefits varying over time and in relation to ambient temperatures. At cold temperatures tree cavities provide significantly higher thermal benefits than nest boxes or wood stacks. Thus, in winter ecology of hole-using endotherms, the availability of tree cavities may be an important characteristic of winter habitat quality.

  1. Variability of Winter Air Temperature in Mid-Latitude Europe

    NASA Technical Reports Server (NTRS)

    Otterman, J.; Ardizzone, J.; Atlas, R.; Bungato, D.; Cierniewski, J.; Jusem, J. C.; Przybylak, R.; Schubert, S.; Starr, D.; Walczewski, J.

    2002-01-01

    The aim of this paper is to report extreme winter/early-spring air temperature (hereinafter temperature) anomalies in mid-latitude Europe, and to discuss the underlying forcing to these interannual fluctuations. Warm advection from the North Atlantic in late winter controls the surface-air temperature, as indicated by the substantial correlation between the speed of the surface southwesterlies over the eastern North Atlantic (quantified by a specific Index Ina) and the 2-meter level air temperatures (hereinafter Ts) over Europe, 45-60 deg N, in winter. In mid-March and subsequently, the correlation drops drastically (quite often it is negative). This change in the relationship between Ts and Ina marks a transition in the control of the surface-air temperature: absorption of insolation replaces the warm advection as the dominant control. This forcing by maritime-air advection in winter was demonstrated in a previous publication, and is re-examined here in conjunction with extreme fluctuations of temperatures in Europe. We analyze here the interannual variability at its extreme by comparing warm-winter/early-spring of 1989/90 with the opposite scenario in 1995/96. For these two December-to-March periods the differences in the monthly mean temperature in Warsaw and Torun, Poland, range above 10 C. Short-term (shorter than a month) fluctuations of the temperature are likewise very strong. We conduct pentad-by-pentad analysis of the surface-maximum air temperature (hereinafter Tmax), in a selected location, examining the dependence on Ina. The increased cloudiness and higher amounts of total precipitable water, corollary effects to the warm low-level advection. in the 1989/90 winter, enhance the positive temperature anomalies. The analysis of the ocean surface winds is based on the Special Sensor Microwave/Imager (SSM/I) dataset; ascent rates, and over land wind data are from the European Centre for Medium-Range Weather Forecasts (ECMWF); maps of 2-m temperature, cloud

  2. Dissolved oxygen in the Tualatin River, Oregon, during winter flow conditions, 1991 and 1992

    USGS Publications Warehouse

    Kelly, V.J.

    1996-01-01

    Throughout the winter period, November through April, wastewater treatment plants in the Tualatin River Basin discharge from 10,000 to 15,000 pounds per day of biochemical oxygen demand to the river. These loads often increase substantially during storms when streamflow is high. During the early winter season, when streamflow is frequently less than the average winter flow, the treatment plants discharge about 2,000 pounds per day of ammonia. This study focused on the capacity of the Tualatin River to assimilat oxygen-demanding loads under winter streamflow conditions during the 1992 water year, with an emphasis on peak-flow conditions in the river, and winter-base-flow conditions during November 1992. Concentrations of dissolved oxygen throughout the main stem of the river during the winter remained generally high relative to the State standard for Oregon of 6 milligrams per liter. The most important factors controlling oxygen consumption during winter-low-flow conditions were carbonaceous biochemical oxygen demand and input of oxygen-depleted waters from tributaries. During peak-flow conditions, reduced travel time and increased dilution associated with the increased streamflow minimized the effect of increased oxygen-demanding loads. During the base-flow period in November 1992, concentrations of dissolved oxygen were consistently below 6 milligrams per liter. A hydrodynamic water-quality model was used to identify the processes depleting dissolved oxygen, including sediment oxygen demand, nitrification, and carbonaceous biochemical oxygen demand. Sediment oxygen demand was the most significant factor; nitrification was also important. Hypothetical scenarios were posed to evaluate the effect of different wastewater treatment plant loads during winter-base-flow conditions. Streamflow and temperature were significant factors governing concentrations of dissolved oxygen in the main-stem river.

  3. Large stratospheric sudden warming in Antarctic late winter and shallow ozone hole in 1988

    SciTech Connect

    Kanzawa, Hiroshi; Kawaguchi, Sadao )

    1990-01-01

    There occurred a large stratospheric sudden warming in the southern hemisphere in late winter of 1988 which competes in suddenness and size with major mid-winter warmings in the northern hemisphere. Associated with the dynamical phenomenon of the sudden warming, total ozone increased over the eastern hemispheric part of Antarctica. The sudden warming as well as other warmings which followed it made the 1988 Antarctic ozone hole shallow in depth and small in area.

  4. Prairie Winter Play Patterns: (b) Winter and Play. Research Project 10.

    ERIC Educational Resources Information Center

    Thomsen, Charles H.; Borowiecka, Alexandra

    This guidebook provides an empirically-based set of planning and design guidelines for the construction of winter play facilities for Canadian youth residing in locations where outdoor play in winter is curtailed for approximately 4 months of the year. Information used in developing the guidelines was derived from field observations, a literature…

  5. Soil aggregates and their associated carbon and nitrogen content in winter annual pastures using different tillage management options

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Traditionally, winter annual pastures are established on grazing areas that are steeply sloping and not regarded as suitable for row-crop production. Using conventional (CT) tillage methods to prepare these fragile lands for winter annual pastures leads to increased erosion and rapid soil degradatio...

  6. Key areas for wintering North American herons

    USGS Publications Warehouse

    Mikuska, T.; Kushlan, J.A.; Hartley, S.

    1998-01-01

    Nearly all North American heron populations are migratory, but details of where they winter are little known. Locations where North American herons winter were identified using banding recovery data. North American herons winter from Canada through northern South America but especially in eastern North America south of New York, Florida, California, Louisiana, Texas, Mexico and Cuba, these areas accounting for 63% of winter recoveries. We identified regions where recoveries for various species clustered as 'key areas.' These forty-three areas constitute a network of areas that hold sites that likely are important to wintering herons. The relative importance of each area and site within the network must be evaluated by further on the ground inventory. Because of biases inherent in the available data, these hypothesized key areas are indicative rather than exhaustive. As a first cut, this network of areas can serve to inform further inventory activities and can provide an initial basis to begin planning for the year-round conservation of North American heron populations.

  7. Comparison of snowpack and winter wet-deposition chemistry in the Rocky Mountains, USA: Implications for winter dry deposition

    USGS Publications Warehouse

    Clow, D.W.; Ingersoll, G.P.; Mast, M.A.; Turk, J.T.; Campbell, D.H.

    2002-01-01

    Depth-integrated snowpack chemistry was measured just prior to maximum snowpack depth during the winters of 1992-1999 at 12 sites co-located with National Atmospheric Deposition Program/National Trend Network (NADP/NTN) sites in the central and southern Rocky Mountains, USA. Winter volume-weighted mean wet-deposition concentrations were calculated for the NADP/NTN sites, and the data were compared to snowpack concentrations using the paired t-test and the Wilcoxon signed-rank test. No statistically significant differences were indicated in concentrations of SO42- or NO3- (p>0.1). Small, but statistically significant differences (p???0.03) were indicated for all other solutes analyzed. Differences were largest for Ca2+ concentrations, which on average were 2.3??eql-1 (43%) higher in the snowpack than in winter NADP/NTN samples. Eolian carbonate dust appeared to influence snowpack chemistry through both wet and dry deposition, and the effect increased from north to south. Dry deposition of eolian carbonates was estimated to have neutralized an average of 6.9??eql-1 and a maximum of 12??eql-1 of snowpack acidity at the southernmost sites. The good agreement between snowpack and winter NADP/NTN SO42- and NO3- concentrations indicates that for those solutes the two data sets can be combined to increase data density in high-elevation areas, where few NADP/NTN sites exist. This combination of data sets will allow for better estimates of atmospheric deposition of SO42- and NO3- across the Rocky Mountain region.

  8. Ecosystem Greenhouse Gas Fluxes Respond Directly to Weather Not Climate: A Case Study on the Relationship of Global Atmospheric Circulation, Foehn Frequency, and Winter Weather to Northern Alps Regional Grassland Phenology and Carbon Cycling

    NASA Astrophysics Data System (ADS)

    Desai, A. R.; Wohlfahrt, G.; Zeeman, M. J.; Katata, G.; Mauder, M.; Schmid, H. P. E.

    2014-12-01

    The impact of climate change on regional ecosystem structure and biogeochemical cycling has two important aspects that require better elaboration to improve projections of these effects. The first is that ecosystems don't respond directly to climate, but indirectly via frequency and occurrence of weather systems, which are driven by climatic shifts in global circulation and radiative processes. The second is that many responses of ecosystems to these weather patterns and extremes are lagged in time. Here, we examine these aspects for northern Alpine grasslands. Long-term eddy covariance flux tower and phenology observations in Austria and Germany and biophysical models reveal a strong influence of winter air temperature, snowfall, and snowmelt frequency on winter grass mortality and spring grassland carbon uptake. Further, the mode of climate variability that drives winter air temperature and snow depth patterns is primarily the frequency of strong regional southerly Foehn flow that promotes warm, dry conditions in winter. Finally, we demonstrate that much of the interannual variance in Foehn frequency and southerly flow is driven by statistics and climatic trends of 500 hPa pressure patterns in Greenland, part of the Arctic Oscillation. However, a few years, including the unusually warm and dry winter of 2013-2014 appear to have secondary, possibly local thermotopographic circulation factors that promoted its weather conditions regionally, which also included primarily cool and wet conditions in northern Europe and the southern Alps. These findings demonstrate that the regional response of ecosystems to climate change is modulated by how large-scale circulation patterns influence local meteorology and topographic flows both during and outside the growing season and provides a framework for future assessment and climate model improvements of linkages of climate change, weather patterns, and ecosystem responses.

  9. Experimental Winter Coccidiosis in Sheltered and Unsheltered Calves

    PubMed Central

    Niilo, L.

    1970-01-01

    Hereford calves, seven months old, were inoculated orally with sporulated oocysts of Eimeria bovis and E. zurnii and housed in a heated building together with uninoculated animals. Duplicate groups of similarly treated animals were left unsheltered in cold winter weather. Clinical coccidiosis developed in most of the inoculated calves, sheltered and unsheltered. There was no marked difference in the severity of the infections. The sheltered uninoculated contact animals remained clinically unaffected, but mild coccidiosis developed in the unsheltered controls. The results suggest that cold may increase the host's susceptibility to clinical coccidiosis, but may not increase the severity of the signs once the clinical infection is established. PMID:4245999

  10. Impact of the winter North Atlantic Oscillation (NAO) on the Western Pacific (WP) pattern in the following winter through Arctic sea ice and ENSO

    NASA Astrophysics Data System (ADS)

    Tachibana, Yoshihiro; Oshika, Miki; Nakamura, Tetsu

    2015-04-01

    This study tested the hypothesis that Asian weather and climate in a given winter can be predicted 1 year in advance. On the basis of a 51-year statistical analysis of reanalysis data, we propose for the first time that the positive phase of the Western Pacific (WP) pattern in the winter is linked to the negative phase of the North Atlantic Oscillation (NAO) in the previous winter, and vice versa. We show that there are two possible mechanisms responsible for this interannual remote linkage. One is an Arctic mechanism. Extensive Arctic sea ice in the summer after a negative NAO acts as a bridge to the positive phase of the WP in the next winter. The negative (positive) phase of the winter NAO changes oceanic currents in the North Atlantic and weakens (strengthens) oceanic heat transport into the Arctic. This weakened (strengthened) heat transport also slows down (speeds up) the reduction of sea ice in the spring. A condition of more (less) ice than normal then persists until the season of ice freezing in autumn. In winter, all of the Arctic Ocean is covered by sea ice, regardless of the autumn ice area. Less (more) ice production during the freezing season reduces (increases) the heat released from the ocean to the atmosphere in the Arctic. An anomalously small (large) heat flux excites stationary Rossby wave propagation, which induces warm (cold) advection to Japan. The other mechanism involves the tropics. An El Niño occurrence after a negative winter NAO acts as another bridge to the positive phase of the WP in the following winter. The timescale of the Arctic route is nearly decadal, whereas that of the tropical route is about 3-5 years. The tropical mechanism indicates that the NAO remotely excites an El Niño in the second half of the following year. A process perhaps responsible for the El Niño occurrence was investigated statistically. A negative NAO in the winter increases Eurasian snow cover. This anomalous snow cover then intensifies the cold air

  11. [Paediatric emergencies; example of the management of winter epidemics].

    PubMed

    Mercier, Jean-Christophe; Bellettre, Xavier; Lejay, Émilie; Desmarest, Marie; Titomanlio, Luigi

    2015-01-01

    Every year, epidemics of viral bronchiolitis and gastroenteritis occur with a significant increase in the number of visits (by a factor 1.8) and hospitalisations that can over-exceed bed capacity leading to transfer sick children to other hospitals. This kind of hospital 'crisis' is not limited to paediatrics, big cities or western nations. It is a worldwide worrying problem. Because our hospital sits in the Northern districts of Paris where a large community of m.ncants lives in poverty, our number of visits is high (mean 250 per day), and winter epidemics further jeopardise the difficult equilibrium achieved between quality management and waiting times. Thus, we have taken various initiatives in terms of organisation of the paediatric emergency department and other wards, including a "fast track" clinic, the opening of beds dedicated to winter epidemics, the institution of a "bed manager" in order to more easily find a bed, and a larger use of home hospitalisations. Furthermore, we created a specific committee which may decide on various indicators of tension whether it is necessary to cancel programmed hospitalisations or surgery.in order to resolve the emergency crisis. This kind of organisation can serve as a model for other hospitals facing winter epidemics crises. PMID:25842428

  12. Winter survival of Eurasian woodcock Scolopax rusticola in central Italy

    USGS Publications Warehouse

    Aradis, A.; Miller, M.W.; Landucci, G.; Ruda, P.; Taddei, S.; Spina, F.

    2008-01-01

    The Eurasian woodcock Scolopax rusticola is a popular game bird in much of Europe. However, little is known about its population dynamics. We estimated winter survival of woodcock in a protected area with no hunting in central Italy. We radio-tagged 68 woodcocks with battery-powered radio-transmitters during 2001-2005. Woodcocks were captured in fields at night from November through February and fitted with radios. Birds were classified on capture as juveniles or adults using plumage characteristics. Woodcocks were relocated daily through March of each year or until they died, disappeared from the study area, or until their radio failed. We constructed a set of eight competing models of daily survival for the period 1 December - 28 February. Estimates of survival were obtained using the program SURVIV and Akaike's Information Criteria. The best model suggested daily survival was a constant 0.9985 (95% CI = 0.9972-0.9998), corresponding to a survival rate of 0.88 (SE = 0.05) for the 90-day winter study period. Our estimate of juvenile survival is higher than previously reported, and may reflect the protected status of the study area. Our estimates of winter survival may be helpful in managing harvested woodcock populations as well as in conserving populations in an increasingly urbanised environment. ?? Wildlife Biology (2008).

  13. Timing of eclosion affects diapause development, fat body consumption and longevity in Osmia lignaria, a univoltine, adult-wintering solitary bee.

    PubMed

    Bosch, Jordi; Sgolastra, Fabio; Kemp, William P

    2010-12-01

    Most insects from temperate areas enter diapause ahead of winter. Species diapausing in a feeding stage and accumulating metabolic reserves during permissive pre-wintering conditions are expected to enter diapause shortly before the onset of winter. In contrast, species diapausing in a non-feeding stage are expected to lower their metabolism as soon as possible to avoid excessive consumption of metabolic reserves. The solitary bee Osmia lignaria winters as a non-feeding adult within its cocoon, but previous studies show important weight losses and increased winter mortality in populations pre-wintered for extended periods. We measured respiration rates to assess diapause initiation and maintenance during pre-wintering, and tested whether timing of adult eclosion affected fitness by measuring fat body depletion, winter mortality and post-winter longevity. We worked with different cohorts of a population reared under natural conditions, and manipulated pre-wintering duration in a population reared under artificial conditions. In agreement with our expectation, O. lignaria lower their metabolic rates within a few days of adult eclosion, but nonetheless suffer strong weight loss during pre-wintering. Early developing individuals suffer greater weight loss and fat body depletion, and have short post-winter longevity. Although, we found no differences in winter mortality among treatments, our results indicate that increased mortality may occur in years with late winter arrivals. We discuss fundamental ecophysiological differences between adult and prepupal diapause within the Megachilidae, and hypothesize that species wintering as adults will be more negatively affected by a situation of extended summers under a scenario of global warming. PMID:20816851

  14. Summer Hot Snaps and Winter Conditions: Modelling White Syndrome Outbreaks on Great Barrier Reef Corals

    PubMed Central

    Heron, Scott F.; Willis, Bette L.; Skirving, William J.; Eakin, C. Mark; Page, Cathie A.; Miller, Ian R.

    2010-01-01

    Coral reefs are under increasing pressure in a changing climate, one such threat being more frequent and destructive outbreaks of coral diseases. Thermal stress from rising temperatures has been implicated as a causal factor in disease outbreaks observed on the Great Barrier Reef, Australia, and elsewhere in the world. Here, we examine seasonal effects of satellite-derived temperature on the abundance of coral diseases known as white syndromes on the Great Barrier Reef, considering both warm stress during summer and deviations from mean temperatures during the preceding winter. We found a high correlation (r2 = 0.953) between summer warm thermal anomalies (Hot Snap) and disease abundance during outbreak events. Inclusion of thermal conditions during the preceding winter revealed that a significant reduction in disease outbreaks occurred following especially cold winters (Cold Snap), potentially related to a reduction in pathogen loading. Furthermore, mild winters (i.e., neither excessively cool nor warm) frequently preceded disease outbreaks. In contrast, disease outbreaks did not typically occur following warm winters, potentially because of increased disease resistance of the coral host. Understanding the balance between the effects of warm and cold winters on disease outbreak will be important in a warming climate. Combining the influence of winter and summer thermal effects resulted in an algorithm that yields both a Seasonal Outlook of disease risk at the conclusion of winter and near real-time monitoring of Outbreak Risk during summer. This satellite-derived system can provide coral reef managers with an assessment of risk three-to-six months in advance of the summer season that can then be refined using near-real-time summer observations. This system can enhance the capacity of managers to prepare for and respond to possible disease outbreaks and focus research efforts to increase understanding of environmental impacts on coral disease in this era of

  15. Dynamic interactions of snow and plants in the boreal forest, winter 2011-2012 revealed by time-lapse photography and LiDAR

    NASA Astrophysics Data System (ADS)

    Filhol, S. V.; Sturm, M.

    2012-12-01

    The winter blanket of snow in the boreal forest is anything but still. In winter 2011-2012 we followed the evolution of a snowpack on a boreal forest plot (0.5 ha) from first snowfall to the beginning of the melt in springtime. We used multiple methods such as time-lapse ground-based LiDAR (Light Detection and Ranging), time-lapse photography, imagery from a suspended cableway, snow-depth sensors, and frequent manual snow-pits. The experimental site is located near Fairbanks, Alaska, a typical boreal forest underlain by permafrost with sparse black spruce, larch, willow, and dwarf birch. We observed snowpack properties to be greatly affected by the vegetation substrate. Interactions between snow and plants are mainly dependent on falling snow properties (rate, wetness), plant heights and stiffness, plant canopy structure (leaves, number of branches, density), succession of weather events (wind before or after snow, thaw events) and pre-existing snow depth. Time-lapse imagery shows interception of snow by trees and shrubs controlled by air-temperature and wind events. LiDAR and snow pit measurements show one class of flexible shrubs (i.e. dwarf birch) bending under load, while a second class (willows) were far stiffer and resisted bending. Where dwarf birch branches were dense, it prevented snow from reaching the ground, leaving a significant air space under the snowpack. This vertical air gap can be as high as 10% of the total snow depth by the end of winter. Improving our understanding of the dynamic relationships between plants and snow is a fundamental key for studying boreal snow physics and snow ecology.

  16. Winter energetics of female Indiana bats Myotis sodalis.

    PubMed

    Day, Katie M; Tomasi, Thomas E

    2014-01-01

    Understanding physiological limits and environmental optima is critical to developing protection strategies for endangered and threatened species. One theory to explain the decline in endangered Indiana bat Myotis sodalis populations involves increasing cave temperatures in winter hibernacula. Altered cave temperatures can raise metabolism and cause more arousals in torpid bats, both of which use more fat reserves. In addition, fluctuations in cave temperatures may cause additional arousals. Our objectives were to quantify the effect of temperature and fluctuations thereof on torpid metabolism and arousal frequency in this species. Female Indiana bats (n=36) were collected from caves just before hibernation, maintained in an environmental chamber that simulated hibernacula conditions, and had skin temperature recorded every 30 min throughout the winter. One environmental chamber containing bats (n=12) was sequentially set at 8°, 6°, and 4°C over the winter. The second chamber containing bats (n=12) experienced the same mean temperatures, but temperature fluctuated ±2°C on a regular basis. Torpor bouts were longest at 4°C and were not affected by temperature fluctuations. However, the temperature fluctuations appeared to cause longer arousals. Other bats (n=12) were individually placed in metabolic chambers to calculate oxygen consumption during torpor and during arousals. Torpid metabolism was affected by temperature; at 9°C, it was higher than at 7° or 5°C. Metabolism during arousals was not different among temperature treatments, but rates were almost 200 times higher than torpid metabolic rates. We calculated a winter energy budget and, from the energetic perspective, determined an optimum hibernation temperature (3°-6°C) for female Indiana bats. These findings suggest that hibernacula that provide these conditions deserve extra protection, although other factors in addition to energetics may play a role in temperature preferences. PMID:24457921

  17. Nuclear winter: the continuing debate. Student essay

    SciTech Connect

    Nida, A.V.

    1987-03-23

    This essay examines the debate over the climatic consequences of global nuclear war as related in the so-called Nuclear Winter hypothesis. This review examines the major components of the theory and traces development of the scientific knowledge leading to a second phase of the controversy two years after the first hypothesis. The conclusions of the essay are that the original nuclear winter findings have been altered by later scientific study and, therefore, the political conclusions drawn by Carl Sagan in 1983 can no longer be supported by theory or facts. Continued use of the Crutzen-Birks (Ambio, 1982) and TTAPS (Science, December 1983) studies worst-case evidence from NCAR (Foreign Affairs, Summer 86) represents selective science. Arguing for strategic policy changes based on nuclear winter risks constitutes anti-nuclear rhetoric and not scientific reasoning.

  18. [Treatment of winter diseases in summer].

    PubMed

    Gao, Zhi-Ping

    2014-04-01

    To explore the connotation and essence of treatment of winter diseases in summer with analysis and deduction. Treating winter diseases in summer is the concrete embodiment and application of taking advantage of "recuperating yang in spring and summer". Winter diseases are formed by compound factors with deficiency of yangqi as the prerequisite and yin as well as cold as the predominant pathogens. Its pathological characteristic rests with stagnation in meri-dians and collaterals. Aiming at curing chronic diseases, reinforcing yangqi and removing stagnation in meridians and collaterals, treatment in summer is a treating strategy focused on proper opportunity of treatment, which is expected to yield twice the result with half the effort. To select the suitable indications is taken as the core of this treating strategy. And at the same time, blind expansion without careful consideration is not suggested. PMID:24946652

  19. BOREAS HYD-5 Winter Surface Flux Data

    NASA Technical Reports Server (NTRS)

    Harding, Richard; Hall, Forrest G. (Editor); Huemmrich, Karl Fred (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The BOREAS HYD-5 team collected tower flux, surface meteorological, and surface temperature data on a frozen lake (Namekus Lake) and in a mature jack pine forest in the Beartrap Creek watershed. Both sites were located in the BOREAS SSA. The objective of this study was to characterize the winter energy and water vapor fluxes, as well as related properties (such as snow density, depth, temperature, and melt) for forested and nonforested areas of the boreal forest. Data were collected on Namekus Lake in the winters of 1994 and 1996, and at Beartrap Creek in the winter of 1994 only. The data are available in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884) or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  20. Risk management model of winter navigation operations.

    PubMed

    Valdez Banda, Osiris A; Goerlandt, Floris; Kuzmin, Vladimir; Kujala, Pentti; Montewka, Jakub

    2016-07-15

    The wintertime maritime traffic operations in the Gulf of Finland are managed through the Finnish-Swedish Winter Navigation System. This establishes the requirements and limitations for the vessels navigating when ice covers this area. During winter navigation in the Gulf of Finland, the largest risk stems from accidental ship collisions which may also trigger oil spills. In this article, a model for managing the risk of winter navigation operations is presented. The model analyses the probability of oil spills derived from collisions involving oil tanker vessels and other vessel types. The model structure is based on the steps provided in the Formal Safety Assessment (FSA) by the International Maritime Organization (IMO) and adapted into a Bayesian Network model. The results indicate that ship independent navigation and convoys are the operations with higher probability of oil spills. Minor spills are most probable, while major oil spills found very unlikely but possible. PMID:27207023

  1. Evaluations on the potential productivity of winter wheat based on agro-ecological zone in the world

    NASA Astrophysics Data System (ADS)

    Wang, H.; Li, Q.; Du, X.; Zhao, L.; Lu, Y.; Li, D.; Liu, J.

    2015-04-01

    Wheat is the most widely grown crop globally and an essential source of calories in human diets. Maintaining and increasing global wheat production is therefore strongly linked to food security. In this paper, the evaluation model of winter wheat potential productivity was proposed based on agro-ecological zone and the historical winter wheat yield data in recent 30 years (1983-2011) obtained from FAO. And the potential productions of winter wheat in the world were investigated. The results showed that the realistic potential productivity of winter wheat in Western Europe was highest and it was more than 7500 kg/hm2. The realistic potential productivity of winter wheat in North China Plain were also higher, which was about 6000 kg/hm2. However, the realistic potential productivity of winter wheat in the United States which is the main winter wheat producing country were not high, only about 3000 kg/hm2. In addition to these regions which were the main winter wheat producing areas, the realistic potential productivity in other regions of the world were very low and mainly less than 1500 kg/hm2, like in southwest region of Russia. The gaps between potential productivity and realistic productivity of winter wheat in Kazakhstan and India were biggest, and the percentages of the gap in realistic productivity of winter wheat in Kazakhstan and India were more than 40%. In Russia, the gap between potential productivity and realistic productivity of winter wheat was lowest and the percentage of the gap in realistic productivity of winter wheat in Russia was only 10%.

  2. Links between solar wind variations, the global electric circuit, and winter cyclone vorticity, and possibly to cold winters in Europe

    NASA Astrophysics Data System (ADS)

    Tinsley, B. A.

    2011-12-01

    There are a number of inputs to the atmosphere and the climate system that are modulated by solar activity that have their only common feature the modulation of the ionosphere-earth current density (Jz) in the global electric circuit, and to which it has now been shown there are small atmospheric responses in winter storm vorticity, surface pressure, and cloud cover. Similar responses are found to internal atmospheric inputs that modulate Jz. An inductive mechanism for initial storm electrification is described that responds to Jz and provides space charge for aerosol particles and droplets throughout the updraft region. The charge on droplets and aerosol particles, by the process of charge modulation of aerosol scavenging (CMAS), increases condensation nuclei concentrations and shifts their distributions to smaller average sizes. This produces smaller and more numerous droplets, and as shown by Rosenfeld et al (2008), delays initial precipitation and increases ice production and the vigor of the storm updraft. For baroclinic storms the additional latent heat release and updraft velocity increases storm vorticity. The result depends on both aerosol characteristics and the Jz variation. The cumulative effect of winter storm intensification, for example in the Icelandic Low cyclogenesis region, responding to Jz changes, is to increase blocking in the Atlantic Ocean. Such blocking reduces the flow of relatively warm moist ocean air onto Europe, while increasing the incidence of outbreaks of cold, dry, Arctic air. The possibility is examined that increases in cosmic ray flux and in Jz, at times of decadal and longer minima in solar activity, contributes to the changes in atmospheric circulation and the resulting unusually severe winters in the UK and Europe such as have occurred during extended solar minima in the late 17th century and early 21st century.

  3. Responses of the photosynthetic apparatus to winter conditions in broadleaved evergreen trees growing in warm temperate regions of Japan.

    PubMed

    Tanaka, Chizuru; Nakano, Takashi; Yamazaki, Jun-Ya; Maruta, Emiko

    2015-01-01

    Photosynthetic characteristics of two broadleaved evergreen trees, Quercus myrsinaefolia and Machilus thunbergii, were compared in autumn and winter. The irradiance was similar in both seasons, but the air temperature was lower in winter. Under the winter conditions, net photosynthesis under natural sunlight (Anet) in both species dropped to 4 μmol CO2 m(-2) s(-1), and the quantum yield of photosystem II (PSII) photochemistry in dark-adapted leaves (Fv/Fm) also dropped to 0.60. In both species the maximum carboxylation rates of Rubisco (V(cmax)) decreased, and the amount of Rubisco increased in winter. A decline in chlorophyll (Chl) concentration and an increase in the Chl a/b ratio in winter resulted in a reduction in the size of the light-harvesting antennae. From measurements of Chl a fluorescence parameters, both the relative fraction and the energy flux rates of thermal dissipation through other non-photochemical processes were markedly elevated in winter. The results indicate that the photosynthetic apparatus in broadleaved evergreen species in warm temperate regions responds to winter through regulatory mechanisms involving the downregulation of light-harvesting and photosynthesis coupled with increased photoprotective thermal energy dissipation to minimize photodamage in winter. These mechanisms aid a quick restart of photosynthesis without the development of new leaves in the following spring. PMID:25500451

  4. Implanting radio transmitters in wintering canvasbacks

    USGS Publications Warehouse

    Olsen, G.H.; Dein, F.J.; Haramis, G.M.; Jorde, D.G.

    1992-01-01

    To conduct telemetry studies of wintering canvasbacks (Aythya valisineria) on Chesapeake Bay, we needed to devise a suitable method of radio transmitter attachment. We describe an aseptic, intra-abdominal surgical technique, using the inhalation anesthetic isoflurane, to implant 20-g radio transmitters in free-ranging canvasbacks. We evaluated the technique over 3 winters (1987-89), when an annual average of 83 female canvasbacks received implant surgery during a 9-day period in mid-December. Of 253 ducks, 248 (98%) were implanted successfully, and 200 (80.6%) completed the 70-day study until early March. No mortality or abnormal behavior from surgery was identified post-release.

  5. Nuclear winter: The evidence and the risks

    SciTech Connect

    Greene, O.

    1985-01-01

    Global concern over nuclear extinction, centered on the holocaust itself, now has turned to the more terrifying consequences of a post-war nuclear winter: ''the long-term effects - destruction of the environment, spread of epidemic diseases, contamination by radioactivity, and ... collapse of agriculture-(that) would spread famine and death to every country.'' Nuclear Winter, the latest in a series of studies by a number of different groups is clinical, analytical, systematic, and detailed. Two physicists and biologist analyze the effects on the climate, plants, animals, and living systems; the human costs; the policy implications.

  6. Field Investigations of Winter Transmission of Eastern Equine Encephalitis Virus in Florida

    PubMed Central

    Bingham, Andrea M.; Burkett-Cadena, Nathan D.; Hassan, Hassan K.; McClure, Christopher J. W.; Unnasch, Thomas R.

    2014-01-01

    Studies investigating winter transmission of Eastern equine encephalitis virus (EEEV) were conducted in Hillsborough County, Florida. The virus was detected in Culiseta melanura and Anopheles quadrimaculatus in February 2012 and 2013, respectively. During the winter months, herons were the most important avian hosts for all mosquito species encountered. In collections carried out in the summer of 2011, blood meals taken from herons were still common, but less frequently encountered than in winter, with an increased frequency of mammalian- and reptile-derived meals observed in the summer. Four wading bird species (Black-crowned Night Heron [Nycticorax nycticorax], Yellow-crowned Night Heron [Nyctanassa violacea], Anhinga [Anhinga anhinga], and Great Blue Heron [Ardea herodias]) were most frequently fed upon by Cs. melanura and Culex erraticus, suggesting that these species may participate in maintaining EEEV during the winter in Florida. PMID:25070997

  7. Field investigations of winter transmission of eastern equine encephalitis virus in Florida.

    PubMed

    Bingham, Andrea M; Burkett-Cadena, Nathan D; Hassan, Hassan K; McClure, Christopher J W; Unnasch, Thomas R

    2014-10-01

    Studies investigating winter transmission of Eastern equine encephalitis virus (EEEV) were conducted in Hillsborough County, Florida. The virus was detected in Culiseta melanura and Anopheles quadrimaculatus in February 2012 and 2013, respectively. During the winter months, herons were the most important avian hosts for all mosquito species encountered. In collections carried out in the summer of 2011, blood meals taken from herons were still common, but less frequently encountered than in winter, with an increased frequency of mammalian- and reptile-derived meals observed in the summer. Four wading bird species (Black-crowned Night Heron [Nycticorax nycticorax], Yellow-crowned Night Heron [Nyctanassa violacea], Anhinga [Anhinga anhinga], and Great Blue Heron [Ardea herodias]) were most frequently fed upon by Cs. melanura and Culex erraticus, suggesting that these species may participate in maintaining EEEV during the winter in Florida. PMID:25070997

  8. [Population trends and behavioral observations of wintering common cranes (Grus grus) in Yancheng Nature Reserve].

    PubMed

    Li, Zhong-Qiu; Wang, Zhi; Ge, Chen

    2013-10-01

    To understand the population status and behavioural features of wintering common cranes in the Yancheng Nature Reserve, two transects were established and population trends were monitored every month over five recent winters from 2008 to 2013. Wintering behaviours were also observed in order to explore the possible effects of family size and age on time budgets. Results indicated that the populations were stable with a range of 303 to 707 individuals. Negative effects of coastal developments were not found on the wintering population of common cranes, which might be related to their diets and preference for artificial wetland habitats. We found a significant effect of age on time budgets, with juveniles spending more time feeding and less time alerting, which might be related to the needs of body development and skill learning. Family size did not affect the time budgets of the cranes, which indicated that adults did not increase vigilance investment even when raising a larger family. PMID:24115655

  9. Lesser scaup winter foraging and nutrient reserve acquisition in east-central Florida

    USGS Publications Warehouse

    Herring, G.; Collazo, J.A.

    2006-01-01

    Lesser scaup (Aythya affinis) populations have been declining since the late 1970s. One of the explanations to account for this decline, the spring-condition hypothesis (SCH), is based on the premise that scaup are limited by their ability to acquire or maintain nutrient reserves during migration to the breeding grounds, leading to an impairment of their reproductive potential. Available evidence suggests that endogenous reserves required for reproduction are obtained at a later stage of migration or after arrival at the breeding grounds, not wintering sites. However, only one study has addressed body-condition levels on a southern wintering site in the last decade, with results limited to the wintering grounds on the Mississippi Flyway. We documented foraging behavior, nutrient levels, and body mass of lesser scaup in east-central Florida, USA, where 62% of the Atlantic Flyway population overwinters, during the winters of 2002 and 2003. Diurnal foraging did not increase seasonally. Nocturnal foraging increased seasonally by 76% or 43 minutes per night in females and by 478% or 1.9 hours per night in males. Measures of body condition did not change seasonally during 2002 for either sex. Between early and later winter in 2003 corrected body mass (CBM) and lipid reserves of male scaup increased 77 g and 39 g, respectively. Our results suggest that lesser scaup maintain or may slightly improve their physiological condition in east-central Florida during winter. Lower body mass and differences in nutrient levels in east-central Florida, compared to a wintering site in Louisiana, likely stem from geographic variation and lower thermal requirements associated with the warmer Florida environment. Lesser scaup depart Florida with sufficient reserves to initiate spring migration, but they maximize nutrient reserves used during reproduction elsewhere during migration or on the breeding grounds. These results suggest that maintaining the ecological integrity of this wintering

  10. Natural and augmented snowfall growth processes and their interactions with the natural and modified aerosol. Final report, 1 March 1989-30 AprIL 1990

    SciTech Connect

    Warburton, J.

    1991-07-01

    The second annual report describes the activities performed under seven separate tasks. These are the same tasks as outlined in the original proposal for the three-year program of research. These tasks dealt with the development of a trace chemical method of assessing the effects of seeding in a snow producing environment and the use of the stable isotopes of water for assessing the regions of ice-phase water capture in the cloud systems from which precipitation fell in the study regions. They also dealt with the theoretical aspects of these trace chemical programs of study and with the roles which trace impurities can play in affecting the growth characteristics of ice particles in supercooled clouds and of the shapes and number fluxes of ice crystals which occur under both natural and artificially seeded conditions. These tasks also included studies of the supercooled liquid water and ice contents of winter storms over the central Sierra Nevada, both spatially and temporally through the use of ground-based remote sensing radar and microwave radiometers. Some work was also conducted on the further development of new aircraft instrumentation for measuring atmospheric motions and the microphysical composition of winter orographic clouds.

  11. Interdecadal and Interannual Variability of Winter Precipitation in Southeast China

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Fraedrich, K.; Zhu, X.; Sielmann, F.

    2013-12-01

    Interdecadal variability of observed winter (DJF) precipitation in Southeast China (1961 to 2010) is characterized by the first EOF of the three-monthly Standardized Precipitation Index (SPI) subjected to a 9-year running mean, while the differences from the original describe the interannual fluctuations. For interdecadal time scales the dominating spatial modes represent monopole features over Southeast China involving the Arctic Oscillation (AO) and the sea surface temperature (SST) anomalies over western Pacific. Dynamic composite analysis (based on NCEP/NCAR and ERA-40 reanalyzes) reveals the following results: (i) Interdecadal SPI-variations show a trend from a dryer state in the 1970s via an increase during the 1980s towards stabilization of wetter conditions commencing with the 1990s. (ii) In mid-to-high latitudes the weakened southward flow of polar airmasses induces low-level warming over Eurasia due to stronger Arctic Oscillation (AO) by warmer zonal temperature advection. This indicates that the precipitation increase in Southeast is attributed circulation anomalies over mid-to-high latitudes which are related to AO. (iii) The abnormal moisture flux along the southwestern boundary of the abnormal anticyclone over south Japan (and its anomalous south-easterlies) is modulated by the sea surface temperature (SST) anomalies over Western Pacific; a positive (negative) SST anomaly will strengthen (weaken) the warm and moist air flow, leading to abundant (less) precipitation in Southeast China. This demonstrates the collaborative effect of AO and SST anomalies in determining the nonlinear trend observed in winter precipitation over Southeast China. For interannual time scales the dominating spatial pattern also represents monopole patterns. Composite analysis (with resampling test) of the associated circulation anomalies reveals the following results: (i) The wet (dry) winter is a result of the strengthened (weakened) northward warm moist air over east coast of

  12. Winter weather versus group thermoregulation: what determines survival in hibernating mammals?

    PubMed

    Patil, V P; Morrison, S F; Karels, T J; Hik, D S

    2013-09-01

    For socially hibernating mammals, the effectiveness of huddling as a means of energy conservation should increase with group size. However, group size has only been linked to increased survival in a few hibernating species, and the relative importance of social structure versus winter conditions during hibernation remains uncertain. We studied the influence of winter weather conditions, social group composition, age-structure, and other environmental factors and individual attributes on the overwinter survival of hoary marmots (Marmota caligata) in the Yukon Territory, Canada. Juvenile hoary marmot survival was negatively correlated with the mean winter (November to May) Pacific Decadal Oscillation (PDO) index. Survival in older age-classes was negatively correlated with PDO lagged by 1 year. Social group size and structure were weakly correlated with survival in comparison to PDO. The relationship between winter PDO and survival was most likely due to the importance of snowpack as insulation during hibernation. The apparent response of hoary marmots to changing winter conditions contrasted sharply with those of other marmot species and other mammalian alpine herbivores. In conclusion, the severity of winter weather may constrain the effectiveness of group thermoregulation in socially hibernating mammals. PMID:23456241

  13. Warmer winters modulate life history and energy storage but do not affect sensitivity to a widespread pesticide in an aquatic insect.

    PubMed

    Arambourou, Hélène; Stoks, Robby

    2015-10-01

    Despite the increased attention for the effects of pesticides under global warming no studies tested how winter warming affects subsequent sensitivity to pesticides. Winter warming is expected to cause delayed negative effects when it increases metabolic rates and thereby depletes energy reserves. Using a common-garden experiment, we investigated the combined effect of a 4 °C increase in winter temperature and subsequent exposure to chlorpyrifos in the aquatic larvae of replicated low- and high-latitude European populations of the damselfly Ischnura elegans. The warmer winter (8 °C) resulted in a higher winter survival and higher growth rates compared to the cold winter (4 °C) commonly experienced by European high-latitude populations. Low-latitude populations were better at coping with the warmer winter, indicating thermal adaptation to the local winter temperatures. Subsequent chlorpyrifos exposure at 20 °C induced strong negative effects on survival, growth rate, lipid content and acetylcholinesterase activity while phenoloxidase activity increased. These pesticide effects were not affected by winter warming. Our results suggest that for species where winter warming has positive effects on life history, no delayed effects on the sensitivity to subsequent pesticide exposure should be expected. PMID:26261878

  14. Climate Change Impacts on Winter and Spring Runoff and Recharge in Wisconsin

    NASA Astrophysics Data System (ADS)

    Murdock, E. A.; Potter, K. W.

    2011-12-01

    Our research seeks to quantify the impacts of warming winter temperatures and increased winter precipitation on water resources in Wisconsin. We are currently working to calibrate a Precipitation-Runoff Modeling System (PRMS) model of the Black Earth Creek Watershed, and will be using a newly-created frost module to examine the impacts of warming winter temperatures on winter and spring infiltration. As a class 1 trout stream, Black Earth Creek is of particular interest as a sensitive and economically important natural resource. Research carried out over 2010 utilized a one-dimensional soil model (Simultaneous Heat and Water, or SHAW) that simulates heat and water fluxes as well as frost processes. This model was driven by climate data obtained from a set of statistically-downscaled and de-biased General Circulation Model (GCM) data for historic and projected future for the years 2046-2065 and 2081-2100 under the SRES A1B emissions scenario. This research suggested that warming temperatures and reduced snow cover, along with a projected increase in winter precipitation, would lead to decreased soil frost formation and a commensurate increase in winter and spring infiltration and recharge. The one-dimensional structure of the model, however, made it difficult to calibrate at the landscape scale, as it is fundamentally unable to replicate the complex spatial processes that are critically important to hydrologic response. We hope that the PRMS model, driven with the same modeled climatic data, will be able to confirm the results of our SHAW modeling; namely that winter and spring recharge will increase significantly in a warming climate. Such an increase in recharge could have profound impacts on Wisconsin fisheries, agriculture, and development.

  15. Distribution of alewives in southeastern Lake Ontario in autumn and winter: a clue to winter mortalities

    USGS Publications Warehouse

    Bergstedt, Roger A.; O'Gorman, Robert

    1989-01-01

    Alewives Alosa pseudoharengus in the Great Lakes are thought to avoid extreme cold in winter by moving to deep water where the temperature is usually highest because of inverse thermal stratification. Information collected in Lake Ontario during autumn and winter 1981–1984 with an echo sounder and bottom and midwater trawls indicated that many alewives remained at depths above 110 m, regardless of water temperature. Alewives in the Great Lakes that did not descend to greater depths would be exposed to potentially lethal temperatures during cold winters.inters.

  16. Winter Secrets: An Instant Lesson Plan.

    ERIC Educational Resources Information Center

    Collyer, Cam

    1997-01-01

    Outdoor lesson plan aims to stimulate student interest in animals' adaptations to winter and the various signs and clues to animal behavior. Includes questions for class discussion, tips for guiding the hike, and instructions for two games that illustrate the predator-prey relationship. Notes curriculum connections to the East York (Ontario) Board…

  17. 43 CFR 423.37 - Winter activities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ....37 Winter activities. (a) You must not tow persons on skis, sleds, or other sliding devices with a motor vehicle or snowmobile, except that you may tow sleds designed to be towed behind snowmobiles if joined to the towing snowmobile with a rigid hitching mechanism, and you may tow disabled snowmobiles...

  18. Winter in Northern Europe (WINE) Project

    NASA Technical Reports Server (NTRS)

    Vonzahn, U.

    1982-01-01

    The scientific aims, work plan, and organization of the Middle Atmosphere Program winter in northern Europe (MAP/WINE) are described. Proposed contributions to the MAP/WINE program from various countries are enumerated. Specific atmospheric parameters to be examined are listed along with the corresponding measurement technique.

  19. Mate loss in winter and mallard reproduction

    USGS Publications Warehouse

    Lercel, B.A.; Kaminski, R.M.; Cox, R.R., Jr.

    1999-01-01

    Mallards (Anas platyrhynchos) frequently pair during winter, and duck hunting seasons have been extended until the end of January in several southern states in the Mississippi Flyway. Therefore, we simulated dissolution of pair bonds from natural or hunting mortality by removing mates of wild-strain, captive, yearling female mallards in late January 1996 and early February 1997 to test if mate loss in winter would affect subsequent pair formation and reproductive performance. Most (97%) widowed females paired again. Nesting and incubation frequencies, nest-initiation date, days between first and second nests, and egg mass did not differ (P > 0.126) between widowed and control (i.e., no mate loss experienced) females in 1996 and 1997. In 1997, widowed females laid 1.91 fewer eggs in first nests (P = 0.014) and 3.75 fewer viable eggs in second nests (P = 0.056). Computer simulations with a mallard productivity model (incorporating default parameters [i.e., average environmental conditions]) indicated that the observed decreased clutch size of first nests, fewer viable eggs in second nests, and these factors combined had potential to decrease recruitment rates of yearling female mallards 9%, 12%, and 20%. Our results indicate that winter mate loss could reduce reproductive performance by yearling female mallards in some years. We suggest caution regarding extending duck hunting seasons in winter without concurrent evaluations of harvest and demographics of mallard and other duck populations.

  20. Music Activities for Lemonade in Winter

    ERIC Educational Resources Information Center

    Cardany, Audrey Berger

    2014-01-01

    "Lemonade in Winter: A Book About Two Kids Counting Money" is a children's book about math; however, when sharing it in the music classroom, street cries and clapping games emerge. Jenkins' and Karas' book provides a springboard to lessons addressing several music elements, including form, tempo, and rhythm, as well as…

  1. The Colgate University Winter Wilderness Survival Program.

    ERIC Educational Resources Information Center

    Haskell, Peter C.; Milner, Robert

    In January 1976, Colgate University offered its first Winter Wilderness Survival Program in conjunction with the North American Wilderness Survival School (NAWSS). This post-program evaluation summarizes background of the three-week program, with attention to the leadership, program aims, how the course was publicized, and how it developed month…

  2. Registration of 'Eve' winter hulless barley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Eve’ (Reg. No. CV- PI 659067 ), a six-row winter hulless barley (Hordeum vulgare L.) developed and tested as VA01H-68 by the Virginia Agricultural Experiment Station was released in May 2007. Eve was derived from the cross SC860974 / VA94-42-13. Eve is widely adapted and provides producers with ...

  3. IMPACT OF OZONE ON WINTER WHEAT YIELD

    EPA Science Inventory

    Wheat is one of the more important agricultural crops in the USA, and the major production areas may be subjected to potentially damaging concentrations of ozone (O3). Since no information was available regarding the O3 sensitivity of winter wheat cultivars grown in the Midwest, ...

  4. Registration of ‘Atlantic’ winter barley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Atlantic’ (Reg. No. CV-354, PI 665041), a six-row, hulled winter barley (Hordeum vulgare L.) tested as VA06B-19 by the Virginia Agricultural Experiment Station, was released in March 2011. Atlantic was derived from the cross VA97B-176/VA92-44-279 using a modified bulk-breeding method. It was evalua...

  5. Winter Video Series Coming in January | Poster

    Cancer.gov

    The Scientific Library’s annual Summer Video Series was so successful that it will be offering a new Winter Video Series beginning in January. For this inaugural event, the staff is showing the eight-part series from National Geographic titled “American Genius.” 

  6. Drag coefficients for winter Antarctic pack ice

    NASA Technical Reports Server (NTRS)

    Wamser, Christian; Martinson, Douglas G.

    1993-01-01

    Air-ice and ice-water drag coefficients referenced to 10-m-height winds for winter Antarctic pack ice based on measurements made from R/V Polarstern during the Winter Weddell Sea Project, 1986 (WWSP-86), and from R/V Akademik Fedorov during the Winter Weddell Gyre Study, 1989 (WWGS-89), are presented. The optimal values of the air-ice drag coefficients, made from turbulent flux measurements, are (1.79 +/- 0.06) x 10 exp -3 for WWSP-86 and (1.45 +/- 0.09) x 10 exp -3 for WWGS-89. A single ice-water drag coefficient for both WWSP-86 and WWGS-89, estimated from periods of ice drift throught to represent free-drift conditions, is (1.13 +/- 0.26) x 10 exp -3, and the ice-water turning angle is 18 +/- 18 deg. It is suggested that for a typical Antarctic winter pack ice cover, the ice cover reduces the momentum flux from the atmosphere to the ocean by about 33 percent.

  7. Hulless winter barley for ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hulless barley is viable feedstock alternative to corn for ethanol production in areas where small grains are produced. The first barley-based ethanol plant in the US is currently under construction by Osage BioEnergy LLC in Hopewell, VA. New hulless winter barley varieties developed by Virginia T...

  8. Appalachia's Winter Secret: Downhill on the Mountains.

    ERIC Educational Resources Information Center

    Johnson, Randy

    1991-01-01

    Describes ski-industry and winter-tourism growth in Appalachia. Sketches ski-resort developments in Maryland, Pennsylvania, North Carolina, and West Virginia. Describes economic threats to industry, its economic impact on Appalachian states and region, resorts' general qualities, and ski industry's promotional efforts. (TES)

  9. Nuclear winter - Physics and physical mechanisms

    NASA Technical Reports Server (NTRS)

    Turco, R. P.; Toon, O. B.; Pollack, J. B.; Ackerman, T. P.; Sagan, C.

    1991-01-01

    The basic physics of the environmental perturbations caused by multiple nuclear detonations is explored, summarizing current knowledge of the possible physical, chemical, and biological impacts of nuclear war. Emphasis is given to the impact of the bomb-generated smoke (soot) particles. General classes of models that have been used to simulate nuclear winter are examined, using specific models as examples.

  10. Registration of Anton Hard White Winter Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Anton’ (Reg. No. CV PI 651043) hard white winter wheat (Triticum aestivum L.) was developed by the USDA-ARS and the Nebraska Agricultural Experiment Station and released in December, 2007. "Anton" was selected from the cross WA691213-27/N86L177//‘Platte’. Anton primarily was released for its lo...

  11. Registration of 'Dan' winter hulless barley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dan’ (Reg. No. CV- , PI 659066) six-rowed winter hulless barley (Hordeum vulgare L.) was developed and released by the Virginia Agricultural Experiment Station in March 2009. Dan was derived from the cross VA96-41-17 / SC872143. It was released for production in the eastern United States, as a poten...

  12. Impact of change in winter strategy of one parasitoid species on the diversity and function of a guild of parasitoids.

    PubMed

    Andrade, Thiago Oliveira; Krespi, Liliane; Bonnardot, Valérie; van Baaren, Joan; Outreman, Yannick

    2016-03-01

    The rise of temperatures may enable species to increase their activities during winter periods and to occupy new areas. In winter, resource density is low for most species and an increased number of active consumers during this season may produce heightened competitive pressure. In Western France, the aphid parasitoid species Aphidius avenae Haliday has been known to adopt a winter diapausing strategy adjacent to newly sown cereal crops, until recent reports of active winter populations in cereal crops. We investigate how the addition of this species to the winter guild of parasitoids may change the structure of the aphid-parasitoid food web and the host-exploitation strategies of previously occurring parasitoids. We showed that in winter, Aphidius avenae was mostly associated with two aphid species, Sitobion avenae Fabricius and Metopolophium dirhodum Walker, while the generalist species Aphidius rhopalosiphi was restricted to the aphid species Rhopalosiphum padi L. in the presence of Aphidius avenae. Due to this new competition, winter food webs present a higher degree of compartmentalization and lower proportional similarity index values than spring ones. Parasitoid and aphid abundances responded significantly to changes in daily high temperatures, suggesting that the host-parasitoid community structure can be partly predicted by climate. This study demonstrates how a change in the winter strategy of one species of a guild can modify complex interspecific relationships in host-parasitoid systems. PMID:26558625

  13. Nuclear Winter: Implications for civil defense

    SciTech Connect

    Chester, C.V.; Perry, A.M.; Hobbs, B.F.

    1988-05-01

    ''Nuclear Winter'' is the term given to the cooling hypothesized to occur in the Northern Hemisphere following a nuclear war as the result of the injection of smoke from burning cities into the atmosphere. The voluminous literature on this subject produced since the paper was published in 1983 by Turco, Toon, Ackerman, Pollack, and Sagen (TTAPS) has been reviewed. Three-dimensional global circulation models have resulted in reduced estimates of cooling---15 to 25/degree/C for a summer war and a few degrees for a winter war. More serious may be the possibility of suppression of convective precipitation by the altered temperature profiles in the atmosphere. However, very large uncertainties remain in input parameters, the models, and the results of calculations. We believe the state of knowledge about nuclear winter is sufficiently developed to conclude: Neither cold nor drought is likely to be a direct threat to human survival for populations with the wherewithal to survive normal January temperatures. The principal threat from nuclear winter is to food production, and this could present problems to third parties who are without food reserves. Loss of a crop year is neither a new nor an unexpected threat from nuclear war to the United States and the Soviet Union. Both have at least a year's food reserve at all times. Both face formidable organizational problems in distributing their reserves in a war-damaged environment. The consequences of nuclear winter could be expected to fall more heavily on the Soviet Union than the United States due to its higher latitude and less productive agriculture. This may be especially true if disturbances of rainfall amounts and distribution persist for more than a year.

  14. Nuclear Winter: The implications for civil defense

    SciTech Connect

    Chester, C.V.; Perry, A.M.; Hobbs, B.F.

    1987-01-01

    ''Nuclear Winter'' is the term given to hypothesized cooling in the northern hemisphere following a nuclear war due to injection of smoke from burning cities into the atmosphere. The voluminous literature on this subject produced since the original paper in 1983 by Turco, Toon, Ackerman, Pollack, and Sagen (TTAPS) has been reviewed. The widespread use of 3-dimensional global circulation models have resulted in reduced estimates of cooling; 15 to 25/sup 0/C for a summer war and a few degrees for a winter war. More serious may be the possibility of suppression of convective precipitation by the altered temperature profiles in the atmosphere. However, very large uncertainties remain in input parameters, the models, and the results of calculations. We believe the state of knowledge about nuclear winter is sufficiently developed to conclude: Neither cold nor drought are likely to be direct threats to human survival for populations with the wherewithal to survive normal January temperatures; The principal threat from nuclear winter is to food production, and could present problems to third parties without food reserves; and Loss of a crop year is neither a new nor unexpected threat from nuclear war to the US and the Soviet Union. Both have at least a year's food reserve at all times. Both face formidable organizational problems in distributing their reserves in a war-damaged environment. The consequences of nuclear winter could be expected to fall more heavily on the Soviet Union than the US due to its higher latitude and less productive agriculture. This may be especially true if disturbances of rainfall amounts and distribution persist for more than a year. 6 refs.

  15. The long winter model of Martian biology - A speculation.

    NASA Technical Reports Server (NTRS)

    Sagan, C.

    1971-01-01

    A temporal microenvironment model is proposed for Martian biology that is based on an estimated mean thickness of nearly 1 km of frost in the Martian north polar cap summer remnant. If vaporized, this frost could yield not only 1 kg per sq cm of atmosphere, but also higher global temperatures through the greenhouse effect and a greatly increased likelihood of liquid water. Vaporization of such cap remnants may occur twice each equinoctial precession, and Martian organisms may now be in cryptobiotic repose awaiting the end of the long precessional winter. The Viking biology experiments might test this hypothesis.

  16. [Effects of ozone stress upon winter wheat photosynthesis, lipid peroxidation and antioxidant systems].

    PubMed

    Zheng, You-fei; Hu, Cheng-da; Wu, Rong-jun; Liu, Rui-na; Zhao, Ze; Zhang, Jin-en

    2010-07-01

    Stress effects of surface increased ozone concentration on winter wheat photosynthesis, lipid peroxidation and antioxidant systems in varied growth stages (jointing stage, booting stage, blooming stage and grain filling stage) were studied, the winter wheat was exposed to open top chambers (OTCs) in an open field conditions to three levels ozone concentrations (CK, 100 nmol x mol(-1), 150 nmol x mol(-1)). The results revealed that within 150 nmol x mol(-1) ozone concentration, as the ozone concentration and time increased,total chlorophyll content,chlorophyll a and b contents of winter wheat leaves were general declined,but compared to CK, the total chlorophyll and chlorophyll a content of T1 treatment groups were a little higher at booting and blooming stage; the conductance of stomatal was affected, the activation of unit leaf area decreased, intercellular CO2 concentration and stomatal limitation value showed a fluctuation change tendency. At the same time, a self-protective mechanism of winter wheat were launched. Concrete expression of SOD activity first increased rapidly and then gradually decreased, the activity of POD showed a decrease firstly and then rapidly increased. From the jointing stage to the blooming stage and from the grain filling stage one to grain filling stage two, the activity of CAT rapidly increased first and then comparatively decreased, but the content of MDA kept steadily rising. The carotenoid content increased first and then decreased, heat dissipation of unit leaf area increased. These results indicate that antioxidant enzymes can not completely eliminate excessive reactive oxygen species in vivo of winter wheat, then lead to accumulation of reactive oxygen species, further exacerbate the lipid peroxidation, that result in the increase of membrane permeability, degradation of chlorophyll, reduction of net photosynthetic rate, imposing on the winter wheat leaves senescence process. PMID:20825039

  17. The role of atmospheric planetary-scale waves in the D region winter anomaly

    NASA Astrophysics Data System (ADS)

    Muraoka, Y.; Petzoldt, K.; Labitzke, K.

    1986-01-01

    Characteristics of the D region winter anomaly are examined, by using ionospheric data along a meridian chain of stations near Japan. The data were obtained by means of long-distance VLF radio wave propagation and HF radio wave vertical sounding. Interesting features are the equatorward extension of the anomaly and the variability of its duration. These features are further discussed in comparison with radiance data measured by pressure modulator radiometer channel 3000 (maximum weight near 80-km altitude in the mesosphere) on board Nimbus 6 during two winters, 1975/1976 and 1976/1977. Meteorological conditions during these winters were quite different, a major stratospheric sudden warming taking place during the latter winter but not during the former winter. The key result of this study is that the occurrence of the winter anomaly is basically associated with the amplification of a planetary-scale wave with zonal wave number 1 in the mesosphere. At the same time we find that the local appearance of the anomaly near Japan is controlled by the movement and latitudinal structure of the excited wave 1. It is further indicated that the increase in mesospheric local temperature is not always associated with the occurrence of the anomaly, suggesting that another dynamical effect of planetary-scale waves is important for the occurrence of the anomaly.

  18. Reproductive arrest and stress resistance in winter-acclimated Drosophila suzukii.

    PubMed

    Toxopeus, Jantina; Jakobs, Ruth; Ferguson, Laura V; Gariepy, Tara D; Sinclair, Brent J

    2016-06-01

    Overwintering insects must survive the multiple-stress environment of winter, which includes low temperatures, reduced food and water availability, and cold-active pathogens. Many insects overwinter in diapause, a developmental arrest associated with high stress tolerance. Drosophila suzukii (Diptera: Drosophilidae), spotted wing drosophila, is an invasive agricultural pest worldwide. Its ability to overwinter and therefore establish in temperate regions could have severe implications for fruit crop industries. We demonstrate here that laboratory populations of Canadian D. suzukii larvae reared under short-day, low temperature, conditions develop into dark 'winter morph' adults similar to those reported globally from field captures, and observed by us in southern Ontario, Canada. These winter-acclimated adults have delayed reproductive maturity, enhanced cold tolerance, and can remain active at low temperatures, although they do not have the increased desiccation tolerance or survival of fungal pathogen challenges that might be expected from a more heavily melanised cuticle. Winter-acclimated female D. suzukii have underdeveloped ovaries and altered transcript levels of several genes associated with reproduction and stress. While superficially indicative of reproductive diapause, the delayed reproductive maturity of winter-acclimated D. suzukii appears to be temperature-dependent, not regulated by photoperiod, and is thus unlikely to be 'true' diapause. The traits of this 'winter morph', however, likely facilitate overwintering in southern Canada, and have probably contributed to the global success of this fly as an invasive species. PMID:27039032

  19. Does Day Length Affect Winter Bird Distribution? Testing the Role of an Elusive Variable

    PubMed Central

    Carrascal, Luis M.; Santos, Tomás; Tellería, José L.

    2012-01-01

    Differences in day length may act as a critical factor in bird biology by introducing time constraints in energy acquisition during winter. Thus, differences in day length might operate as a main determinant of bird abundance along latitudinal gradients. This work examines the influence of day length on the abundance of wintering crested tits (Lophophanes cristatus) in 26 localities of Spanish juniper (Juniperus thurifera) dwarf woodlands (average height of 5 m) located along a latitudinal gradient in the Spanish highlands, while controlling for the influence of food availability, minimum night temperature, habitat structure and landscape characteristics. Top regression models in the AIC framework explained 56% of variance in bird numbers. All models incorporated day length as the variable with the highest magnitude effect. Food availability also played an important role, although only the crop of ripe juniper fruits, but not arthropods, positively affected crested tit abundance. Differences in vegetation structure across localities had also a strong positive effect (average tree height and juniper tree density). Geographical variation in night temperature had no influence on crested tit distribution, despite the low winter temperatures reached in these dwarf forests. This paper demonstrates for the first time that winter bird abundance increases with day length after controlling for the effect of other environmental variables. Winter average difference in day length was only 10.5 minutes per day along the 1°47′ latitudinal interval (190 km) included in this study. This amount of time, which reaches 13.5 h accumulated throughout the winter season, appears to be large enough to affect the long-term energy budget of small passerines during winter and to shape the distribution of winter bird abundance under restrictive environmental conditions. PMID:22393442

  20. Climate Change Affects Winter Chill for Temperate Fruit and Nut Trees

    PubMed Central

    Luedeling, Eike; Girvetz, Evan H.; Semenov, Mikhail A.; Brown, Patrick H.

    2011-01-01

    Background Temperate fruit and nut trees require adequate winter chill to produce economically viable yields. Global warming has the potential to reduce available winter chill and greatly impact crop yields. Methodology/Principal Findings We estimated winter chill for two past (1975 and 2000) and 18 future scenarios (mid and end 21st century; 3 Global Climate Models [GCMs]; 3 greenhouse gas emissions [GHG] scenarios). For 4,293 weather stations around the world and GCM projections, Safe Winter Chill (SWC), the amount of winter chill that is exceeded in 90% of all years, was estimated for all scenarios using the “Dynamic Model” and interpolated globally. We found that SWC ranged between 0 and about 170 Chill Portions (CP) for all climate scenarios, but that the global distribution varied across scenarios. Warm regions are likely to experience severe reductions in available winter chill, potentially threatening production there. In contrast, SWC in most temperate growing regions is likely to remain relatively unchanged, and cold regions may even see an increase in SWC. Climate change impacts on SWC differed quantitatively among GCMs and GHG scenarios, with the highest GHG leading to losses up to 40 CP in warm regions, compared to 20 CP for the lowest GHG. Conclusions/Significance The extent of projected changes in winter chill in many major growing regions of fruits and nuts indicates that growers of these commodities will likely experience problems in the future. Mitigation of climate change through reductions in greenhouse gas emissions can help reduce the impacts, however, adaption to changes will have to occur. To better prepare for likely impacts of climate change, efforts should be undertaken to breed tree cultivars for lower chilling requirements, to develop tools to cope with insufficient winter chill, and to better understand the temperature responses of tree crops. PMID:21629649

  1. Winter Ecology of the Western Burrowing Owl (Athene cunicularia hypugaea) in Southern Texas 1999-2004

    USGS Publications Warehouse

    Woodin, Marc C.; Skoruppa, Mary K.; Hickman, Graham C.

    2007-01-01

    This study examines the winter ecology of the western burrowing owl (Athene cunicularia hypugaea) in five Texas counties surrounding Corpus Christi, in southern Texas. There is a substantial gap in information on the owl's life cycle during migration and non-breeding winter months; almost all previous research on western burrowing owls has been conducted during the breeding season. The western burrowing owl currently is federally threatened in Mexico, federally endangered in Canada, and in the United States is considered a National Bird of Conservation Concern by the U.S. Fish and Wildlife Service. Topics investigated included status, effectiveness of public outreach, roost sites and use of culverts and artificial burrows, roost site fidelity, diet, contaminant burdens, body mass, and ectoparasites. Early ornithological reports and a museum egg set revealed that burrowing owls once bred in southern Texas and were common in winter; however, since the 1950's they have been reported in relatively low numbers and only during winter. In this study, public outreach increased western burrowing owl detections by 68 percent. Owls selected winter roost sites with small-diameter openings, including culverts less than or equal to 16 centimeters and artificial burrows of 15 centimeters, probably because the small diameters deterred mammalian predators. Owls showed strong roost site fidelity; 15 banded birds stayed at the same roost sites within a winter, and 8 returned to the same site the following winter. The winter diet was over 90 percent insects, with crickets the primary prey. Analyses of invertebrate prey and regurgitated pellets showed that residues of all but 3 of 28 carbamate and organophosphate pesticides were detected at least once, but all were below known lethal concentrations. Mean body mass of western burrowing owls was 168 grams and was highest in midwinter. Feather lice were detected in low numbers on a few owls, but no fleas or other ectoparasites were found.

  2. Sustainability of winter tourism in a changing climate over Kashmir Himalaya.

    PubMed

    Dar, Reyaz Ahmad; Rashid, Irfan; Romshoo, Shakil Ahmad; Marazi, Asif

    2014-04-01

    Mountain areas are sensitive to climate change. Implications of climate change can be seen in less snow, receding glaciers, increasing temperatures, and decreasing precipitation. Climate change is also a severe threat to snow-related winter sports such as skiing, snowboarding, and cross-country skiing. The change in climate will put further pressure on the sensitive environment of high mountains. Therefore, in this study, an attempt has been made to know the impact of climate change on the snow precipitation, water resources, and winter tourism in the two famous tourist resorts of the Kashmir Valley. Our findings show that winters are getting prolonged with little snow falls on account of climate change. The average minimum and maximum temperatures are showing statistically significant increasing trends for winter months. The precipitation is showing decreasing trends in both the regions. A considerable area in these regions remains under the snow and glacier cover throughout the year especially during the winter and spring seasons. However, time series analysis of LandSat MODIS images using Normalized Difference Snow Index shows a decreasing trend in snow cover in both the regions from past few years. Similarly, the stream discharge, comprising predominantly of snow- and glacier-melt, is showing a statistically significant declining trend despite the melting of these glaciers. The predicted futuristic trends of temperature from Predicting Regional Climates for Impact Studies regional climate model are showing an increase which may enhance snow-melting in the near future posing a serious threat to the sustainability of winter tourism in the region. Hence, it becomes essential to monitor the changes in temperature and snow cover depletion in these basins in order to evaluate their effect on the winter tourism and water resources in the region. PMID:24318957

  3. Projecting Future Change in Growing Degree Days of Winter Wheat

    NASA Astrophysics Data System (ADS)

    Ruiz Castillo, N.; Gaitan Ospina, C. F.; Mcpherson, R. A.

    2015-12-01

    Southwest Oklahoma is one of the most productive regions in the Great Plains where winter wheat is produced. To assess the effect of climate change on the growing degree days (GDD) available for winter wheat production, we selected from the CMIP5 archive, two of the best performing Global Climate Models (GCMs) for the region (MIROC5 and CCSM4) to project the future change in GDD under the Representative Concentration Pathway (RCP) 8.5 —a "business as usual" future trajectory for greenhouse gas concentrations. Two quantile mapping downscaling methods were applied to both GCMs to obtain local scale projections. The downscaled outputs were applied to a GDD formula to show the GDD changes between the historical period (1961-2004) and the future period (2006-2098) in terms of mean differences. The results show that at the end of the 2098 growing season, the increase in GDD is expected to be between -2.0 and 6. Depending on the GCM used, Southwest Oklahoma is expected to see an increase in future GDD under the CCSM4 GCM and a mix of increase, no change and decrease under the MIROC5 GCM.

  4. Pinatubo eruption winter climate effects: Model versus observations

    NASA Technical Reports Server (NTRS)

    Graf, HANS-F.; Kirchner, Ingo; Schult, Ingrid; Robock, Alan

    1992-01-01

    Large volcanic eruptions, in addition to the well-known effect of producing global cooling for a year or two, have been observed to produce shorter-term responses in the climate system involving non-linear dynamical processes. In this paper, we use the ECHAM2 general circulation model forced with stratospheric aerosols to test some of these ideas. Run in a perpetual-January mode, with tropical stratospheric heating from the volcanic aerosols typical of the 1982 El Chichon eruption or the 1991 Pinatubo eruption, we find a dynamical response with an increased polar night jet in the Northern Hemisphere (NH) and stronger zonal winds which extended down into the troposphere. The Azores High shifts northward with increased tropospheric westerlies at 60N and increased easterlies at 30N. Surface temperatures are higher both in northern Eurasia and North America, in agreement with observations for the NH winters or 1982-83 and 1991-92 as well as the winters following the other 10 largest volcanic eruptions since 1883.

  5. Field Demonstration of Automated Demand Response for Both Winter and Summer Events in Large Buildings in the Pacific Northwest

    SciTech Connect

    Piette, Mary Ann; Kiliccote, Sila; Dudley, Junqiao H.

    2011-11-11

    There are growing strains on the electric grid as cooling peaks grow and equipment ages. Increased penetration of renewables on the grid is also straining electricity supply systems and the need for flexible demand is growing. This paper summarizes results of a series of field test of automated demand response systems in large buildings in the Pacific Northwest. The objective of the research was two fold. One objective was to evaluate the use demand response automation technologies. A second objective was to evaluate control strategies that could change the electric load shape in both winter and summer conditions. Winter conditions focused on cold winter mornings, a time when the electric grid is often stressed. The summer test evaluated DR strategies in the afternoon. We found that we could automate both winter and summer control strategies with the open automated demand response communication standard. The buildings were able to provide significant demand response in both winter and summer events.

  6. Seeding date affects fall growth of winter canola (Brassica napus L. ‘Baldur’) and its performance as a winter cover crop in central Iowa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In recent years, interest has increased in finding non-grass cover crop species that could be planted after soybean (Glycine max (L) Merr.) and before corn (Zea mays L.) in Iowa crop rotations. In this study, we investigate the use of winter canola (Brassica napus L.) as an alternative cover crop fo...

  7. Seeding date affects fall growth of winter canola (1 Brassica napus L. ‘Baldur’) and its performance as a winter cover crop in central Iowa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In recent years, interest has increased in finding non-grass cover crop species that could be planted after soybean (Glycine max (L) Merr.) and before corn (Zea mays L.) in Iowa crop rotations. In this study, we investigate the use of winter canola (Brassica napus L.) as an alternative cover crop fo...

  8. Measurement of evapotranspiration in a winter wheat field

    NASA Astrophysics Data System (ADS)

    Zhang, Yongqiang; Liu, Changming; Shen, Yanjun; Kondoh, A.; Tang, Changyuan; Tanaka, T.; Shimada, J.

    2002-10-01

    Daily evapotranspiration from a winter wheat field on the North China Plain measured by large-scale weighing lysimeter was linearly related to that measured by the Bowen ratio energy balance (BREB) technique. Soil evaporation averaged about 23·6% of evapotranspiration from the post-winter dormancy revival stage to the grain ripening stage in 1999. On clear days during winter dormancy, about half of the net radiation flux Rn was used to warm soil. During the revival stage, conductive heat flux G also used most of the incoming Rn, but the ratio of latent heat flux E to Rn increased. During the stem-extension stage, E was about 50% of Rn; thereafter, E/Rincreased continually, but

  9. Attribution of UK Winter Floods to Anthropogenic Forcing

    NASA Astrophysics Data System (ADS)

    Schaller, N.; Alison, K.; Sparrow, S. N.; Otto, F. E. L.; Massey, N.; Vautard, R.; Yiou, P.; van Oldenborgh, G. J.; van Haren, R.; Lamb, R.; Huntingford, C.; Crooks, S.; Legg, T.; Weisheimer, A.; Bowery, A.; Miller, J.; Jones, R.; Stott, P.; Allen, M. R.

    2014-12-01

    Many regions of southern UK experienced severe flooding during the 2013/2014 winter. Simultaneously, large areas in the USA and Canada were struck by prolonged cold weather. At the time, the media and public asked whether the general rainy conditions over northern Europe and the cold weather over North America were caused by climate change. Providing an answer to this question is not trivial, but recent studies show that probabilistic event attribution is feasible. Using the citizen science project weather@home, we ran over 40'000 perturbed initial condition simulations of the 2013/2014 winter. These simulations fall into two categories: one set aims at simulating the world with climate change using observed sea surface temperatures while the second set is run with sea surface temperatures corresponding to a world that might have been without climate change. The relevant modelled variables are then downscaled by a hydrological model to obtain river flows. First results show that anthropogenic climate change led to a small but significant increase in the fractional attributable risk for 30-days peak flows for the river Thames. A single number can summarize the final result from probabilistic attribution studies indicating, for example, an increase, decrease or no change to the risk of the event occurring. However, communicating this to the public, media and other scientists remains challenging. The assumptions made in the chain of models used need to be explained. In addition, extreme events, like the UK floods of the 2013/2014 winter, are usually caused by a range of factors. While heavy precipitation events can be caused by dynamic and/or thermodynamic processes, floods occur only partly as a response to heavy precipitation. Depending on the catchment, they can be largely due to soil properties and conditions of the previous months. Probabilistic attribution studies are multidisciplinary and therefore all aspects need to be communicated properly.

  10. Is winter worse for stressed fish? The consequences of exogenous cortisol manipulation on over-winter survival and condition of juvenile largemouth bass.

    PubMed

    Binder, Thomas R; O'Connor, Constance M; McConnachie, Sarah H; Wilson, Samantha M; Nannini, Michael A; Wahl, David H; Cooke, Steven J

    2015-09-01

    Over-winter mortality is an important selective force for warm-water fish (e.g., centrarchids) that live in temperate habitats. Inherent challenges faced by fish during winter may be compounded by additional stressors that activate the hypothalamic-pituitary-interrenal axis, either before or during winter, leading to negative sub-lethal impacts on fish health and condition, and possibly reducing chance of survival. We used experimental cortisol manipulation to test the hypothesis that juvenile largemouth bass (Micropterus salmoides) exposed to semi-chronic elevation in cortisol prior to winter would experience higher levels of over-winter mortality, physiological alterations and impaired immune status relative to control and sham-treated bass. Over-winter survival in experimental ponds was high, averaging 83%, and did not differ among treatment groups. Over the study period, bass exhibited an average increase in mass of 19.4%, as well as a slight increase in Fulton's condition factor, but neither measure differed among groups. Hepatosomatic index in cortisol-treated bass was 23% lower than in control fish, suggesting lower energy status, but white muscle lipid content was similar across all groups. Lastly, there was no difference in spleen somatic index or parasite load among treatment groups, indicating no long-term immune impairment related to our cortisol manipulation. The current study adds to a growing body of literature on glucocorticoid manipulations where field-based findings are not consistent with laboratory-based conceptual understanding of multiple stressors. This suggests that field conditions may provide fish with opportunities to mitigate negative effects of some stressors. PMID:26006297

  11. Effects of winter atmospheric circulation on temporal and spatial variability in annual streamflow in the western United States

    USGS Publications Warehouse

    McCabe, G.J., Jr.

    1996-01-01

    Winter mean 700-hectoPascal (hPa) height anomalies, representing the average atmospheric circulation during the snow season, are compared with annual streamflow measured at 140 streamgauges in the western United States. Correlation and anomaly pattern analyses are used to identify relationships between winter mean atmospheric circulation and temporal and spatial variability in annual streamflow. Results indicate that variability in winter mean 700-Hpa height anomalies accounts for a statistically significant portion of the temporal variability in annual streamflow in the western United States. In general, above-average annual streamflow is associated with negative winter mean 700-Hpa height anomalies over the eastern North Pacific Ocean and/or the western United States. The anomalies produce an anomalous flow of moist air from the eastern North Pacific Ocean into the western United States that increases winter precipitation and snowpack accumulations, and subsequently streamflow. Winter mean 700-hPa height anomalies also account for statistically significant differences in spatial distributions of annual streamflow. As part of this study, winter mean atmospheric circulation patterns for the 40 years analysed were classified into five winter mean 700-hPa height anomaly patterns. These patterns are related to statistically significant and physically meaningful differences in spatial distributions of annual streamflow.

  12. Winter climate change and coastal wetland foundation species: salt marshes vs. mangrove forests in the southeastern United States.

    PubMed

    Osland, Michael J; Enwright, Nicholas; Day, Richard H; Doyle, Thomas W

    2013-05-01

    We live in an era of unprecedented ecological change in which ecologists and natural resource managers are increasingly challenged to anticipate and prepare for the ecological effects of future global change. In this study, we investigated the potential effect of winter climate change upon salt marsh and mangrove forest foundation species in the southeastern United States. Our research addresses the following three questions: (1) What is the relationship between winter climate and the presence and abundance of mangrove forests relative to salt marshes; (2) How vulnerable are salt marshes to winter climate change-induced mangrove forest range expansion; and (3) What is the potential future distribution and relative abundance of mangrove forests under alternative winter climate change scenarios? We developed simple winter climate-based models to predict mangrove forest distribution and relative abundance using observed winter temperature data (1970-2000) and mangrove forest and salt marsh habitat data. Our results identify winter climate thresholds for salt marsh-mangrove forest interactions and highlight coastal areas in the southeastern United States (e.g., Texas, Louisiana, and parts of Florida) where relatively small changes in the intensity and frequency of extreme winter events could cause relatively dramatic landscape-scale ecosystem structural and functional change in the form of poleward mangrove forest migration and salt marsh displacement. The ecological implications of these marsh-to-mangrove forest conversions are poorly understood, but would likely include changes for associated fish and wildlife populations and for the supply of some ecosystem goods and services. PMID:23504931

  13. Winter climate change and coastal wetland foundation species: salt marshes vs. mangrove forests in the southeastern United States

    USGS Publications Warehouse

    Osland, Michael J.; Day, Richard H.; Doyle, Thomas W.; Enwright, Nicholas

    2013-01-01

    We live in an era of unprecedented ecological change in which ecologists and natural resource managers are increasingly challenged to anticipate and prepare for the ecological effects of future global change. In this study, we investigated the potential effect of winter climate change upon salt marsh and mangrove forest foundation species in the southeastern United States. Our research addresses the following three questions: (1) What is the relationship between winter climate and the presence and abundance of mangrove forests relative to salt marshes; (2) How vulnerable are salt marshes to winter climate change-induced mangrove forest range expansion; and (3) What is the potential future distribution and relative abundance of mangrove forests under alternative winter climate change scenarios? We developed simple winter climate-based models to predict mangrove forest distribution and relative abundance using observed winter temperature data (1970–2000) and mangrove forest and salt marsh habitat data. Our results identify winter climate thresholds for salt marsh–mangrove forest interactions and highlight coastal areas in the southeastern United States (e.g., Texas, Louisiana, and parts of Florida) where relatively small changes in the intensity and frequency of extreme winter events could cause relatively dramatic landscape-scale ecosystem structural and functional change in the form of poleward mangrove forest migration and salt marsh displacement. The ecological implications of these marsh-to-mangrove forest conversions are poorly understood, but would likely include changes for associated fish and wildlife populations and for the supply of some ecosystem goods and services.

  14. Postharvest tillage reduces Downy Brome infestations in winter wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Pacific Northwest, downy brome continues to infest winter wheat producing regions especially in low-rainfall areas where the winter wheat-summer fallow rotation is the dominate production system. In Washington, a study was conducted for 2 years at each of two locations in the winter wheat -su...

  15. Latitudinal variation in population structure of wintering Pacific Black Brant

    USGS Publications Warehouse

    Schamber, J.L.; Sedinger, J.S.; Ward, D.H.; Hagmeier, K.R.

    2007-01-01

    Latitudinal variation in population structure during the winter has been reported in many migratory birds, but has been documented in few species of waterfowl. Variation in environmental and social conditions at wintering sites can potentially influence the population dynamics of differential migrants. We examined latitudinal variation in sex and age classes of wintering Pacific Black Brant (Branta bernicla nigricans). Brant are distributed along a wide latitudinal gradient from Alaska to Mexico during the winter. Accordingly, migration distances for brant using different wintering locations are highly variable and winter settlement patterns are likely associated with a spatially variable food resource. We used resightings of brant banded in southwestern Alaska to examine sex and age ratios of birds wintering at Boundary Bay in British Columbia, and at San Quintin Bay, Ojo de Liebre Lagoon, and San Ignacio Lagoon in Baja California from 1998 to 2000. Sex ratios were similar among wintering locations for adults and were consistent with the mating strategy of geese. The distribution of juveniles varied among wintering areas, with greater proportions of juveniles observed at northern (San Quintin Bay and Ojo de Liebre Lagoon) than at southern (San Ignacio Lagoon) locations in Baja California. We suggest that age-related variation in the winter distribution of Pacific Black Brant is mediated by variation in productivity among individuals at different wintering locations and by social interactions among wintering family groups.

  16. 33 CFR 401.92 - Wintering and laying-up.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Wintering and laying-up. 401.92... OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations General § 401.92 Wintering and laying-up. No vessel shall winter within the Seaway or lay-up within the Seaway during the navigation...

  17. 33 CFR 401.92 - Wintering and lying-up.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Wintering and lying-up. 401.92... OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations General § 401.92 Wintering and lying-up. No vessel shall winter within the Seaway or lie-up within the Seaway during the navigation...

  18. 33 CFR 401.92 - Wintering and laying-up.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Wintering and laying-up. 401.92... OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations General § 401.92 Wintering and laying-up. No vessel shall winter within the Seaway or lay-up within the Seaway during the navigation...

  19. 33 CFR 401.92 - Wintering and lying-up.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Wintering and lying-up. 401.92... OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations General § 401.92 Wintering and lying-up. No vessel shall winter within the Seaway or lie-up within the Seaway during the navigation...

  20. 33 CFR 401.92 - Wintering and lying-up.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Wintering and lying-up. 401.92... OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations General § 401.92 Wintering and lying-up. No vessel shall winter within the Seaway or lie-up within the Seaway during the navigation...

  1. Sources and contributions of wood smoke during winter in London

    NASA Astrophysics Data System (ADS)

    Crilley, Leigh; Bloss, William; Yin, Jianxin; Beddows, David; Harrison, Roy; Zotter, Peter; Prevot, Andre; Green, David

    2014-05-01

    Determining the contribution of wood smoke in large urban centres such as London is becoming increasingly important with the changing nature of domestic heating partly due to the installation of biomass burning heaters to meet renewable energy targets imposed by the EU and also a rise in so-called recreational burning for aesthetic reasons (Fuller et al., 2013). Recent work in large urban centres (London, Paris and Berlin) has demonstrated an increase in the contribution of wood smoke to ambient particles during winter that can at times exceed traffic emissions. In Europe, biomass burning has been identified as a major cause of exceedances of European air quality limits during winter (Fuller et al., 2013). In light of the changing nature of emissions in urban areas there is a need for on-going measurements to assess the impact of biomass burning in cities like London. Therefore we aimed to determine quantitatively the contribution of biomass burning in London and surrounding rural areas. We also aimed to determine whether local emissions or regional sources were the main source of biomass burning in London. Sources of wood smoke during winter in London were investigated at an urban background site (North Kensington) and two surrounding rural sites (Harwell and Detling) by analysing selected wood smoke chemical tracers. Concentrations of levoglucosan, elemental carbon (EC), organic carbon (OC) and K+ were generally well correlated, indicating a similar source of these species at the three sites. Based on the conversion factor for levoglucosan, mean wood smoke mass at Detling, North Kensington and Harwell was 0.78, 0.87 and 1.0 µg m-3, respectively. At all the sites, biomass burning was found to be a source of OC and EC, with the largest source of OC and EC found to be secondary organic aerosols and traffic emissions, respectively. Peaks in levoglucosan concentrations at the sites were observed to coincide with low ambient temperature, suggesting domestic heating as

  2. Characteristics of foraging sites and protein status in wintering muskoxen: Insights from isotopes of nitrogen

    USGS Publications Warehouse

    Gustine, D.D.; Barboza, P.S.; Lawler, J.P.; Arthur, S.M.; Shults, B.S.; Persons, K.; Adams, L.G.

    2011-01-01

    Identifying links between nutritional condition of individuals and population trajectories greatly enhances our understanding of the ecology, conservation, and management of wildlife. For northern ungulates, the potential impacts of a changing climate to populations are predicted to be nutritionally mediated through an increase in the severity and variance in winter conditions. Foraging conditions and the availability of body protein as a store for reproduction in late winter may constrain productivity in northern ungulates, yet the link between characteristics of wintering habitats and protein status has not been established for a wild ungulate. We used a non-invasive proxy of protein status derived from isotopes of N in excreta to evaluate the influence of winter habitats on the protein status of muskoxen in three populations in Alaska (2005-2008). Multiple regression and an information-theoretic approach were used to compare models that evaluated the influence of population, year, and characteristics of foraging sites (components of diet and physiography) on protein status for groups of muskoxen. The observed variance in protein status among groups of muskoxen across populations and years was partially explained (45%) by local foraging conditions that affected forage availability. Protein status improved for groups of muskoxen as the amount of graminoids in the diet increased (-0.430 ?? 0.31, ???? 95% CI) and elevation of foraging sites decreased (0.824 ?? 0.67). Resources available for reproduction in muskoxen are highly dependent upon demographic, environmental, and physiographic constraints that affect forage availability in winter. Due to their very sedentary nature in winter, muskoxen are highly susceptible to localized foraging conditions; therefore, the spatial variance in resource availability may exert a strong effect on productivity. Consequently, there is a clear need to account for climate-topography effects in winter at multiple scales when

  3. Winter protein requirements of bobwhite quail

    USGS Publications Warehouse

    Nestler, R.B.; Bailey, W.W.; Llewellyn, L.M.; Rensberger, M.J.

    1944-01-01

    Three experiments involving 714 bobwhite quail were conducted at the Patuxent Research Refuge, Bowie, Maryland, during the winters of 1939-1941 to determine the protein requirement of quail maintained throug'h the winter.....Considering survival, live weights, feed consumption, and subsequent reproduction by the birds, the-9 to 13 per cent levels of crude dietary protein gave as good results as higher levels eggs, which in all cases was over 90 per and in some respects were better.....On the basis of these studies, it is recommended that the winter maintenance diet for bobwhite quail contain . about 11 to 12 per cent of crude protein. The following diet (parts by weight) conforms to these specifications and should be satisfactory:...Ground yellow corn 85.6....Dehvdrated alfalfa leaf meal 5 .O.....Soybean oil meal 7.0.....Special steamed bonemeal 1.2....Salt (or Salt Mixture II,see text) 1.0...Vitamin A and D feeding oil, fortified 0.2.

  4. An NOy Algorithm for Arctic Winter 2000

    NASA Technical Reports Server (NTRS)

    Loewenstein, M.; Jost, H.; Greenblatt, J. B.; Podolske, J. R.; Gao, R. S.; Popp, P. J.; Toon, G. C.; Webster, C. R.; Herman, R. L.; Hurst, D. F.; Hipskind, R. Stephen (Technical Monitor)

    2000-01-01

    NOy, total reactive nitrogen, and the long-lived tracer N2O, nitrous oxide, were measured by both in situ and remote sensing instruments during the Arctic winter 1999-2000 SAGE III Ozone Loss and Validation Experiment (SOLVE). The correlation function NOy:N2O observed before the winter Arctic vortex forms, which is known as NOy(sup), is an important reference relationship for conditions in the evolving vortex. NOy(sup) can, with suitable care, be used to quantify vortex denitrification by sedimentation of polar stratospheric cloud particles when NOy data is taken throughout the winter. Observed NOy values less than the reference value can be interpreted in terms of semi-permanent removal of active nitrogen by condensation and sedimentation processes. In this paper we present a segmented function representing NOy(sup) applicable over the full range of altitudes sampled during SOLVE. We also assess the range of application of this function and some of its limitations.

  5. Dehydration in the Winter Arctic Tropopause Region

    NASA Technical Reports Server (NTRS)

    Pfister, Leonhard; Jensen, Eric; Podolske, James; Selkirk, Henry; Anderson, Bruce; Avery, Melody; Diskin. Glenn

    2004-01-01

    Recent work has shown that limited amounts of tropospheric air can penetrate as much as 1 km into the middleworld stratosphere during the arctic winter. This, coupled with temperatures that are cold enough to produce saturation mixing ratios of less than 5 ppmv at the tropopause, results in stratospheric cloud formation and upper tropospheric dehydration. Even though these "cold outbreaks" occupy only a small portion of the area in the arctic (1-2%), their importance is magnified by an order of magnitude because of the air flow through them. This is reinforced by evidence of progressive drying through the winter measured during SOLVE-1. The significance of this process lies in its effect on the upper tropospheric water content of the middle and high latitude tropopause region, which plays an important role in regulating the earth's radiative balance. There appears to be significant year-to-year variability in the incidence of the cold outbreaks. This work has two parts. First, we describe case studies of dehydration taken from the SOLVE and SOLVE2 aircraft sampling missions during the Arctic winters of 2000 and 2003 respectively. Trajectory based microphysical modeling is employed to examine the sensitivity of the dehydration to microphysical parameters and the nature of sub-grid scale temperature fluctuations. We then examine the year-to-year variations in potential dehydration using a trajectory climatology.

  6. Impact of future warming on winter chilling in Australia.

    PubMed

    Darbyshire, Rebecca; Webb, Leanne; Goodwin, Ian; Barlow, E W R

    2013-05-01

    Increases in temperature as a result of anthropogenically generated greenhouse gas (GHG) emissions are likely to impact key aspects of horticultural production. The potential effect of higher temperatures on fruit and nut trees' ability to break winter dormancy, which requires exposure to winter chilling temperatures, was considered. Three chill models (the 0-7.2°C, Modified Utah, and Dynamic models) were used to investigate changes in chill accumulation at 13 sites across Australia according to localised temperature change related to 1, 2 and 3°C increases in global average temperatures. This methodology avoids reliance on outcomes of future GHG emission pathways, which vary and are likely to change. Regional impacts and rates of decline in chilling differ among the chill models, with the 0-7.2°C model indicating the greatest reduction and the Dynamic model the slowest rate of decline. Elevated and high latitude eastern Australian sites were the least affected while the three more maritime, less elevated Western Australian locations were shown to bear the greatest impact from future warming. PMID:22674019

  7. Changes in hematological profiles during winter field operations

    SciTech Connect

    Lopez, A.; Reed, L.; D'Alesandro, M. )

    1991-03-11

    The authors have previously shown that there are changes in hematological profiles during experimental cold acclimation. They now report on hematological changes in 9 military volunteers during a 12 week winter field operation and show results similar to those observed during experimental cold acclimation. Blood was collected before and after completion of winter field operations and analyzed in a paired fashion. Hematocrit (HCT) and erythrocyte counts (RBC) were decreased; mean corpuscular hemoglobin concentration (MCHC) and plasma volume (PV), which was calculated from hemoglobin (Hb) concentration and HCT, were increased. In addition, the reticulocyte count was increased from 1.37 {plus minus} 0.10% to 2.62 {plus minus} 0.24% after completion of field operations. There was a statistically significant inverse correlation between HCT and reticulocyte count, indicating the need for an enhanced rate of red cell production. Hemoglobin concentration, leukocyte count, and mean corpuscular volume were unchanged. The RBC population, to remain at steady state during periods of chronic cold exposure, shows alterations in the number of circulating cells, Hb concentration per cell and possibly cell turnover.

  8. Assessing solar energy and water use efficiencies in winter wheat

    NASA Technical Reports Server (NTRS)

    Asrar, G.; Hipps, L. E.; Kanemasu, E. T.

    1982-01-01

    The water use and solar energy conversion efficiencies of two cultivars of winter wheat (Triticum aestivum L., vars, Centurk and Newton) planted at three densities, were examined during a growing season. Water use, based on soil moisture depletion, was the lowest under the light, and the highest under the heavy planting densities of both cultivars. Water use efficiency of medium and heavy planting densities were greater than the light planting densities in both cultivars. The canopy radiation extinction coefficients of both cultivars increased with increases in planting density. Efficiency of operation interception of photosynthetically active radiation by both cultivars improved from the time of jointing until anthesis, and then decreased during senescence. The efficiency of the conversion of intercepted radiation to dry matter (biochemical efficiency) decreased throughout the growing season both cultivars. The interception, biochemical, and photosynthetic efficiencies improved as planting density increased.

  9. Effects of winter road grooming on bison in YNP

    USGS Publications Warehouse

    Bjornlie, Daniel D; Garrott, R.A.

    2001-01-01

    The effects of winter recreation—specifically snowmobiling—on wildlife in Yellowstone National Park (YNP) have become high-profile management issues. The road grooming needed to support oversnow travel in YNP is also being examined for its effects on bison (Bison bison) ecology. Data were collected from November 1997 through May 1998 and from December 1998 through May 1999 on the effects of road grooming on bison in Madison–Gibbon–Firehole (MGF) area of YNP Peak bison numbers occurred during late March—early April and were strongly correlated with the snow water equivalent measurements in the Hayden Valley area (1997–1998: r* = 0.62, p:0.001: 1998–1999: r2 = 0.64, P-0.001). Data from an infrared trail monitor on the Mary Mountain trail between the Hayden and Firehole valleys suggest that this trail is the sole corridor for major bison distributional shifts between these locations. Of the 28,293 observations of individual bison made during the study, 8% were traveling and 69% were foraging. These percentages were nearly identical during the period of winter road grooming (7% and 68%, respectively). During this period, 77% of bison foraging activity and 12% of bison traveling activity involved displacing snow. Most travel took place off roads (P<0.001), Bison utilized geothermal features, a network of trails they established, and river and stream banks for travel. Bison road use was negatively correlated with road grooming, with peak use in April and lowest use during the road-grooming period. Bison in the MGF area of YNF neither seek out nor avoid groomed roads. The minimal use of roads compared to off-road areas, the short distances traveled on the roads, the decreased use of roads during the over snow vehicle (OSV) season, and the increased costs of negative interactions with OSVs suggest that grooming roads during winter does not have a major influence on bison ecology.

  10. Forage kochia (Kochia Prostrata) increases nutritional value, carrying capacity, and livestock performance on semiarid rangelands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Extending the grazing season into the fall and winter increases the sustainability of livestock production by reducing winter feed costs. However, without exception, stockpiled range grasses do not meet nutritional requirements for ruminant livestock. This study compared fall/winter grazing of tra...

  11. Recurring Cold Winters over the Gulf Stream and Implications for Northern Hemisphere Ocean Circulation

    NASA Astrophysics Data System (ADS)

    Strey, S. T.

    2015-12-01

    As polar amplification of climate warming continues, the potential for increased blocking patterns in the Northern Hemisphere jet stream in conjunction with Arctic climate change exists. During such blocking events the Gulf Stream may be exposed to repeated Cold Air Outbreak (CAO) events, especially during winter. Hypothesizing, based upon basic physical and thermodynamic properties of seawater, one would expect increased CAO events to lead alteration of key characteristics of the Gulf Stream. As the Gulf Stream is a well-known participant in the Atlantic meridional overturning circulation (AMOC), and the Gulf Stream feeds the North Atlantic Current into the Arctic Ocean, interesting consequences to alterations of this local system into the large-scale general climate circulation are expected. This study uses CESM's POP to examine 30 years of CAO intensive winters alongside 30 years of repeated winter warm events to quantify potential subsequent changes in the AMOC and North Atlantic Arctic Ocean inflow.

  12. Migration and wintering areas of glaucous-winged Gulls from south-central Alaska

    USGS Publications Warehouse

    Hatch, Shyla A.; Gill, V.A.; Mulcahy, D.M.

    2011-01-01

    We used satellite telemetry to investigate the migration patterns and wintering areas of Glaucouswinged Gulls (Larus glaucescens) from Middleton Island, Alaska, where this species' population increased tenfold from the 1970s to the 1990s. Fall migration spanned 11 weeks, including numerous stopovers en route, apparently for feeding. Spring migration from wintering sites to Middleton Island was shorter (4 weeks) and more direct. One juvenile spent several months in southern Prince William Sound. An adult spent several months near Craig, southeast Alaska, while three others overwintered in southern British Columbia. For all four wintering adults use of refuse-disposal sites was evident or strongly suggested. Commensalism with humans may have contributed to the increase on Middleton, but a strong case can also be made for a competing explanation-regional recruitment of gulls to high-quality nesting habitat in Alaska created after the earthquake of 1964. An analysis of band returns reveals broad overlap in the wintering grounds of gulls from different Alaska colonies and of gulls banded on the west coast from British Columbia to California. The seasonal movement of many gulls from Alaska is decidedly migratory, whereas gulls from British Columbia, Washington, and Oregon disperse locally in winter. ?? The Cooper Ornithological Society 2011.

  13. Migration And wintering areas Of Glaucous-winged Gulls From south-central Alaska

    USGS Publications Warehouse

    Hatch, Scott A.; Gill, V.A.; Mulcahy, Daniel M.

    2011-01-01

    We used satellite telemetry to investigate the migration patterns and wintering areas of Glaucous-winged Gulls (Larus glaucescens) from Middleton Island, Alaska, where this species' population increased tenfold from the 1970s to the 1990s. Fall migration spanned 11 weeks, including numerous stopovers en route, apparently for feeding. Spring migration from wintering sites to Middleton Island was shorter (4 weeks) and more direct. One juvenile spent several months in southern Prince William Sound. An adult spent several months near Craig, southeast Alaska, while three others overwintered in southern British Columbia. For all four wintering adults use of refuse-disposal sites was evident or strongly suggested. Commensalism with humans may have contributed to the increase on Middleton, but a strong case can also be made for a competing explanation-regional recruitment of gulls to high-quality nesting habitat in Alaska created after the earthquake of 1964. An analysis of band returns reveals broad overlap in the wintering grounds of gulls from different Alaska colonies and of gulls banded on the west coast from British Columbia to California. The seasonal movement of many gulls from Alaska is decidedly migratory, whereas gulls from British Columbia, Washington, and Oregon disperse locally in winter.

  14. Effects of weather on habitat selection and behavior of mallards wintering in Nebraska

    USGS Publications Warehouse

    Jorde, D.G.; Krapu, G.L.; Crawford, R.D.; Hay, M.A.

    1984-01-01

    Sex and age ratios, habitat selection, spatial characteristics, and time budgets of Mallards (Anas platyrhynchos) wintering on the Platte River in south central Nebraska were studied from mid-December to early April 1978-1980. The proportion of females and subadults in the population increased substantially from a cold to a mild winter. Radio-tagged Mallards shifted from riverine to canal roost sites during the coldest periods of the winter, seemingly because of more favorable microclimatic conditions there. Subadults ranged over larger areas during winter than did adults. Activity patterns varied with weather conditions, time of day, and habitat type. During cold periods, energetically costly activities such as aggression and courtship decreased at roost sites and the intensity of foraging activities in fields increased. Mallards were more active at riverine than canal sites during both years. High energy requirements and intense competition for scarce food appear to be primary factors limiting the northernmost distribution of Mallards in winter and causing their skewed sex and age ratios.

  15. Condition of Euphausia crystallorophias off East Antarctica in winter in comparison to other seasons

    NASA Astrophysics Data System (ADS)

    Nicol, S.; Virtue, P.; King, R.; Davenport, S. R.; McGaffin, A. F.; Nichols, P.

    2004-08-01

    Antarctic coastal krill ( Euphausia crystallorophias) were collected in Austral winter (July/August) 1999 in the Mertz Glacier polynya off the coast of East Antarctica and were compared to krill collected off East Antarctica during summer in 1996 and 2001 and spring 1999. A range of experiments and measurements were conducted to assess their relative condition in winter and summer. Krill collected in winter had pale yellow-green digestive glands, indicating some recent feeding activity. The size of the digestive glands was small relative to those of krill caught in summer. This indicates that feeding had been occurring at low levels during the collection period. Growth rates, measured using the instantaneous growth rate methodology, were close to zero in winter (range -5% to 7% per moult). This was an indication that some food had been available during the period of the moult cycle. Growth rates in spring ranged from -0.5% to +8.7% per moult and from 4% to 12% per moult in the summer. The mean length of the winter moult cycle (68 days) was considerably greater than the measured intermoult period in summer and spring (24-33 days). Lipid levels were low in winter, less than 5% of body weight, compared to summer levels of ˜15% (dry weight). Winter krill were richer in wax esters and poorer in polar lipids than specimens collected in summer. Krill in winter were lacking in C16 PUFA that are markers of the phytoplankton diet common in summer krill. Krill caught in the winter had significantly higher levels of 20:1 and 22:1 fatty acids (2.3%) and alcohols (8.1%) than krill sampled in summer (0.2%, 0%), indicating a shift to a carnivorous diet. Results from this study suggest that E. crystallorophias respond to low food abundance during the winter through metabolic and physiological processes. These processes were reflected in a decrease in growth rate and a significant increase in the intermoult period. The process of lipid utilisation and switching to a carnivorous

  16. Association of wintering raptors with Conservation Reserve Enhancement Program grasslands in Pennsylvania

    USGS Publications Warehouse

    Wilson, A.; Brittingham, M.; Grove, G.

    2010-01-01

    Conservation grasslands can provide valuable habitat resource for breeding songbirds, but their value for wintering raptors has received little attention. We hypothesized that increased availability of grassland habitat through the Conservation Reserve Enhancement Program (CREP) has resulted in an increase or redistribution in numbers of four species of raptors in Pennsylvania since 2001. We tested this by analyzing winter raptor counts from volunteer surveys, conducted from 2001 to 2008, for Red-tailed Hawks (Buteo jamaicensis), Rough-legged Hawks (Buteo lagopus), Northern Harriers (Circus cyaneus), and American Kestrels (Falco sparverius). During that period, numbers of wintering Northern Harriers increased by more than 20% per year. Log-linear Poisson regression models show that all four species increased in the region of Pennsylvania that had the most and longest-established conservation grasslands. At the county scale (N= 67), Bayesian spatial models showed that spatial and temporal population trends of all four species were positively correlated with the amount of conservation grassland. This relationship was particularly strong for Northern Harriers, with numbers predicted to increase by 35.7% per year for each additional 1% of farmland enrolled in CREP. Our results suggest that conservation grasslands are likely the primary cause of the increase in numbers of wintering Northern Harriers in Pennsylvania since 2001. ?? 2010 The Authors. Journal of Field Ornithology ?? 2010 Association of Field Ornithologists.

  17. El Niño-Southern Oscillation Impacts on Winter Vegetable Production in Florida*.

    NASA Astrophysics Data System (ADS)

    Hansen, James W.; Jones, James W.; Kiker, Clyde F.; Hodges, Alan W.

    1999-01-01

    Florida's mild winters allow the state to play a vital role in supplying fresh vegetables for U.S. consumers. Producers also benefit from premium prices when low temperatures prevent production in most of the country. This study characterizes the influence of the El Niño-Southern Oscillation (ENSO) on the Florida vegetable industry using statistical analysis of the response of historical crop (yield, prices, production, and value) and weather variables (freeze hazard, temperatures, rainfall, and solar radiation) to ENSO phase and its interaction with location and time of year. Annual mean yields showed little evidence of response to ENSO phase and its interaction with location. ENSO phase and season interacted to influence quarterly yields, prices, production, and value. Yields (tomato, bell pepper, sweet corn, and snap bean) were lower and prices (bell pepper and snap bean) were higher in El Niño than in neutral or La Niña winters. Production and value of tomatoes were higher in La Niña winters. The yield response can be explained by increased rainfall, reduced daily maximum temperatures, and reduced solar radiation in El Niño winters. Yield and production of winter vegetables appeared to be less responsive to ENSO phase after 1980; for tomato and bell pepper, this may be due to improvements in production technology that mitigate problems associated with excess rainfall. Winter yield and price responses to El Niño events have important implications for both producers and consumers of winter vegetables, and suggest opportunities for further research.

  18. Tillage Management and Seasonal Effects on Denitrifier Community Abundance, Gene Expression and Structure over Winter.

    PubMed

    Tatti, Enrico; Goyer, Claudia; Burton, David L; Wertz, Sophie; Zebarth, Bernie J; Chantigny, Martin; Filion, Martin

    2015-10-01

    Tillage effects on denitrifier communities and nitrous oxide (N2O) emissions were mainly studied during the growing season. There is limited information for the non-growing season, especially in northern countries where winter has prolonged periods with sub-zero temperatures. The abundance and structure of the denitrifier community, denitrification gene expression and N2O emissions in fields under long-term tillage regimes [no-tillage (NT) vs conventional tillage (CT)] were assessed during two consecutive winters. NT exerted a positive effect on nirK and nosZ denitrifier abundance in both winters compared to CT. Moreover, the two contrasting managements had an opposite influence on nirK and nirS RNA/DNA ratios. Tillage management resulted in different denitrifier community structures during both winters. Seasonal changes were observed in the abundance and the structure of denitrifiers. Interestingly, the RNA/DNA ratios were greater in the coldest months for nirK, nirS and nosZ. N2O emissions were not influenced by management but changed over time with two orders of magnitude increase in the coldest month of both winters. In winter of 2009-2010, emissions were mainly as N2O, whereas in 2010-2011, when soil temperatures were milder due to persistent snow cover, most emissions were as dinitrogen. Results indicated that tillage management during the growing season induced differences in denitrifier community structure that persisted during winter. However, management did not affect the active cold-adapted community structure. PMID:25851442

  19. Combined effect of the Arctic Oscillation and the Western Pacific pattern on East Asia winter temperature

    NASA Astrophysics Data System (ADS)

    Park, Hye-Jin; Ahn, Joong-Bae

    2016-05-01

    The combined effect of the Arctic Oscillation (AO) and Western Pacific (WP) teleconnection pattern on the temperature variation during the winter in the northern hemisphere and East Asia over the last 56 years (1958/1959-2013/2014) was investigated using NCEP/NCAR reanalysis data. The study results revealed that the effect of the AO on winter temperature in East Asia could be changed depending on the phase of the WP pattern in the North Pacific. The negative relationship between the temperature of East Asia (25-45°N, 110-145°E) and the AO increased when the AO and WP were in-phase with each other. Hence, when winter negative (positive) AO was accompanied by negative (positive) WP, negative (positive) temperature anomalies were dominant across the entire East Asia region. Conversely, when the AO and WP were out-of-phase, the winter temperature anomaly in East Asia did not show distinct changes. Furthermore, from the perspective of stationary planetary waves, the zonal wavenumber-2 patterns of sea level pressure and geopotential height at 500 hPa related to the East Asian winter monsoon (EAWM) circulation strengthened when the AO and WP were in-phase but were not significant for the out-of-phase condition. An index considering the effect of both AO and WP on East Asia winter temperature was proposed. The correlation between the index and the East Asia winter temperature was statistically significant at the 99 % confidence level. The index was correlated with synoptic characteristics of the EAWM, including the Siberian High, East Asian trough, East Asian jet stream and surface air temperature.

  20. Foraging behavior of redheads (Aythya americana) wintering in Texas and Louisiana

    USGS Publications Warehouse

    Woodin, M.C.; Michot, T.C.

    2006-01-01

    Redheads, Aythya americana, concentrate in large numbers annually in traditional wintering areas along the western and northern rim of the Gulf of Mexico. Two of these areas are the Laguna Madre of Texas and Chandeleur Sound of Louisiana. We collected data on 54,340 activities from 103 redhead flocks in Texas and 51,650 activities from 57 redhead flocks in Louisiana. Males and females fed similarly, differing neither in levels of feeding (percent of all birds in flock that were feeding) (p>0.90) nor in percentages of birds feeding by diving, tipping, dipping, or gleaning from the surface (p>0.10). The foraging level of redheads in the upper Laguna Madre region was relatively constant throughout two winters. Foraging of redheads in early winter in Louisiana was significantly greater than redhead foraging in the upper Laguna Madre, but by late winter, foraging by redheads in Louisiana had declined to the same level as that shown by redheads foraging in the upper Laguna Madre. The overall foraging level of redheads from Chandeleur Sound was greater (41%) than that of redheads in the upper Laguna Madre (26%), yet it was quite similar to the 46% foraging level reported for redheads from the lower Laguna Madre. Redheads in the upper Laguna Madre region of Texas fed more by diving than did those in the Chandeleur Sound and the lower Laguna Madre. Diving increased in frequency in late winter. Greater reliance by redheads on diving in January and February indicates that the birds altered their foraging to feed in deeper water, suggesting that the large concentrations of redheads staging at this time for spring migration may have displaced some birds to alternative foraging sites. Our results imply that the most likely period for food resources to become limiting for wintering redheads is when they are staging in late winter. ?? Springer 2006.

  1. Improved seasonal prediction of winter NAO through ensemble sub-sampling.

    NASA Astrophysics Data System (ADS)

    Dobrynin, Mikhail; Domeisen, Daniela I. V.; Müller, Wolfgang A.; Bell, Louisa; Brune, Sebastian; Bunzel, Felix; Fröhlich, Kristina; Pohlmann, Holger; Baehr, Johanna

    2016-04-01

    Over the North Atlantic, the North Atlantic Oscillation (NAO index represented as the difference in sea level pressure between the Azores islands and Iceland) is a major mode of winter climate variability. The seasonal and shorter term variability of the NAO has widespread impacts on changes in temperature and precipitation, marine ecosystems and storm track location. Results of the seasonal prediction system based on the mixed resolution CMIP5 version of the Max Planck Institute for Meteorology Earth System Model (MPI-ESM-MR) will be presented. In our 30-member ensemble re-forecast over the period from 1982 to 2014 the correlation between the ensemble mean and ERA-Interim winter NAO index is 0.52. Moreover, based on the knowledge that the NAO index is connected with dynamical variability of the Earth system over a large geographical region through teleconnections, we investigate the impact of autumn state of the Earth system on the subsequent winter NAO. We show that the predictive skill for the winter NAO can be significantly enhanced through ensemble sub-sampling considering the physical mechanisms behind the longer term predictive potential of the autumn state and the subsequent winter NAO. By retaining only the ensemble members that show a physically coherent evolution between the the initial autumn state and the subsequent winter NAO state, the correlation coefficient between the forecasted and reanalysed winter NAO index significantly increases from the ensemble-mean to the sub-sampled ensemble-mean from 0.52 to 0.85. For the selection of the ensemble members, only observations from the initial state are taken into account, hence the presented approach is applicable in current operational (seasonal) prediction systems.

  2. The contribution of litter derived carbon to winter respiration in an alpine tundra ecosystem

    NASA Astrophysics Data System (ADS)

    Wipf, S.; Siegwolf, R.; Esperschuetz, J.; Hagedorn, F.

    2009-04-01

    Although soil respiration rates from snow-covered ecosystems are relatively low, they add up to a substantial fraction of the annual CO2 efflux over the whole winter, which lasts for more than half of the year in the Alpine. It is still unclear, however, which carbon sources are respired preferentially in winter. In a new experiment at the Stillberg tree line research site near Davos, Switzerland, we added 13C-labelled litter (Leucanthemopsis alpina L.) to an alpine tundra ecosystem and measured its contribution to the CO2 efflux at different soil temperatures over winter. The litter was placed either at the soil surface or at 5 cm depth, and soil temperature was decreased by manually reducing snow depth to half of of that of the control plots. Soil respiration was measured by means of a chamber system, and gas samples were analysed for their isotopic composition. Preliminary results indicate that soil respiration in early winter was about half compared to that measured in late fall. Lower soil temperatures under a shallow snow cover further decreased respiration by 40%. Litter addition increased respiration rates by 10 to 30%. At the beginning of the winter season, a higher respiration rate was found for the plots where litter was applied at the surface than at 5 cm soil depth. This effect, however, decreased with the progression of the winter as later measurements have shown. The isotopic composition of the respired CO2 suggests that carbon from the additional litter contributed about 5 to 15% to the total CO2 efflux, and that this fraction was higher in plots with lower soil temperatures. Our results show considerable and non negligible amounts of C-loss in winter. By exploring the effect of the snow cover and soil temperatures on the decomposition of fresh plant litter, this experiment will give a more detailed insight into the environmental controls of soil respiration processes and the sources of respiratory CO2 release in Alpine ecosystems.

  3. CHEOPS III: An ozone research campaign in the arctic winter stratosphere 1989/90

    SciTech Connect

    Pommereau, J.P. ); Schmidt, U. )

    1991-04-01

    CHEOPS ( = CHemistry of Ozone in the Polar Stratosphere) is a research project that began in 1987 as an initiative to join efforts of scientists from Germany and France combining their resources and capacities to conduct field experiments in the winter Arctic stratosphere. On February 5, two experiments, a cryogenic whole air sampler and an active chemical ionization mass spectrometer, were launched with a large scientific balloon from the ESA/SSC Rocket Base ESRANGE near Kiruna in Northern Sweden (68{degree} N, 20{degree} E). The scientific objective was to look for a possible latitudinal difference in the vertical distributions of various minor constituents in the lower and middle stratosphere during winter. The International Ozone Trends Panel reported a systematic decrease in total ozone by about 6% in the Arctic winter stratosphere over the period 1969-86. This finding motivated several European research groups to continue the CHEOPS program by regular field campaigns organized in the Arctic region. During the CHEOPS II campaign conducted in winter 1987/88 four payloads were launched in cooperation with the balloon launching team of the French Centre National d'Etudes Spatiales (CNES). On the basis of the tests and improvements of the instrumentation achieved during the previous winter campaign, CHEOPS III was planned for winter 1989/90 as a more ambitious field experiment. In addition to balloon-borne and ground-based observations, the program included an increased number of regular ozone sonde launches at various Scandinavian stations. The primary objective was to investigate the composition of the lower Arctic stratosphere during winter until early February, when temperatures were lowest and episodes of perturbed chemistry during PSC events were most likely to occur.

  4. First records of winter sea ice concentration in the southwest Pacific sector of the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Ferry, Alexander J.; Crosta, Xavier; Quilty, Patrick G.; Fink, David; Howard, William; Armand, Leanne K.

    2015-11-01

    We use a Generalized Additive Model (GAM) to provide the first winter sea ice concentration record from two cores located within the southwest Pacific sector of the Southern Ocean. To compliment the application of GAM, a time series analysis on satellite records of sea ice concentration data was used to extend the standard 13.25 year time series used for paleoceanography. After comparing GAM sea ice estimates with previously published paleo sea ice data we then focus on a new paleo winter sea ice record for marine sediment core E27-23 (59°37.1'S, 155°14.3'E), allowing us to provide a more comprehensive view of winter sea ice dynamics for the southwest Pacific Ocean. The paleo winter sea ice concentration estimates provide the first suggestion that winter sea ice within the southwestern Pacific might have expanded during the Antarctic Cold Reversal. Throughout the Holocene, core E27-23 documents millennial scale variability in paleo winter sea ice coverage within the southwest Pacific. Holocene winter sea ice expansion may have resulted from the Laurentide Ice Sheet deglaciation, increased intensity of the westerly winds, as well as a northern migration of the Subtropical and/or Sub-Antarctic Fronts. Brief consideration is given to the development of a paleo summer sea ice proxy. We conclude that there is no evidence that summer sea ice ever existed at core sites SO136-111 and E27-23 over the last 220 and 52,000 years, respectively.

  5. Climate and smoke: an appraisal of nuclear winter.

    PubMed

    Turco, R P; Toon, O B; Ackerman, T P; Pollack, J B; Sagan, C

    1990-01-12

    The latest understanding of nuclear winter is reviewed. Considerable progress has been made in quantifying the production and injection of soot by large-scale fires, the regional and global atmospheric dispersion of the soot, and the resulting physical, environmental, and climatic perturbations. New information has been obtained from laboratory studies, field experiments, and numerical modeling on a variety of scales (plume, mesoscale, and global). For the most likely soot injections from a full-scale nuclear exchange, three-dimensional climate simulations yield midsummer land temperature decreases that average 10 degrees to 20 degrees C in northern mid-latitudes, with local cooling as large as 35 degrees C, and subfreezing summer temperatures in some regions. Anomalous atmospheric circulations caused by solar heating of soot is found to stabilize the upper atmosphere against overturning, thus increasing the soot lifetime, and to accelerate interhemispheric transport, leading to persistent effects in the Southern Hemisphere. Serious new environmental problems associated with soot injection have been identified, including disruption of monsoon precipitation and severe depletion of the stratospheric ozone layer in the Northern Hemisphere. The basic physics of nuclear winter has been reaffirmed through several authoritative international technical assessments and numerous individual scientific investigations. Remaining areas of uncertainty and research priorities are discussed in view of the latest findings. PMID:11538069

  6. Winter Eurasian Climate Variability: Role of Cyclone and Anticyclone Activity

    NASA Astrophysics Data System (ADS)

    Lu, C.; Zhang, X.; Guan, Z.

    2012-12-01

    This study investigates variability of extratropical Eurasian cyclone and anticyclone activity by using a modified automated cyclone and anticyclone identification and tracking algorithm. The cyclone and anticyclone activities are quantified by their regionally integrated intensity (CI and ACI) during 1978/79-2011/2012 winter seasons. We found that the time evolutions of the CI and ACI exhibit a general negative correlation of -0.7 between them at a significant level of 99.99%. This anticyclone (cyclone) variability contributes to the substantially large-scale sea level pressure variability over extratropical Eurasian continent, and explains the interannual fluctuation of surface air temperature over mid latitude Eurasia as well as the adjacent continents. The ACI swings from one phase to another, also producing large changes in snow cover extend, snow equivalent water as well as frequency of extreme cold events over the Eurasian continent. The strengthening of anticyclone intensity is preceded by retreated of the October sea-ice extent over Barents-Kara Sea, which associates tightly with an increasing stability at lower troposphere around the Ural Mountains and induces strengthening Eurasian anticyclones activity in the subsequent winter.

  7. Summer melt regulates winter glacier flow speeds throughout Alaska (Invited)

    NASA Astrophysics Data System (ADS)

    Burgess, E. W.; Forster, R. R.; Larsen, C. F.

    2013-12-01

    Projecting the long-term response of glacier and ice sheet flow to climate change remains the single largest hurdle towards accurate sea level rise forecasting. Increases in surface melt rates are known to accelerate glacier flow in spring and summer1-4 whereas in winter, flow speeds have been found to be relatively invariant5. Here we find that wintertime flow velocities on nearly all major glaciers throughout Alaska are not only variable but are inversely correlated with summertime positive degree days (PDDs). The response is slight--an 11% decrease in wintertime velocity per additional meter of summertime melt. The mechanism is likely due to inter-annual differences in summertime meltwater production, which affect the efficiency of sub-glacial drainage systems to evacuate water from the glacier bed in fall. Consequent inter-annual variation in the amount of bed separation come winter leads to the observed differences in flow speed. We find this mechanism to be ubiquitous in Alaska and thus is likely a global phenomenon. If the dynamic evolves over the long-term, it represents a new mechanism affecting sea level rise contributions.

  8. Processes Controlling Water Vapor in the Winter Arctic Tropopause Region

    NASA Technical Reports Server (NTRS)

    Pfister, Leonhard; Selkirk, Henry B.; Jensen, Eric J.; Padolske, James; Sachse, Glen; Avery, Melody; Schoeberl, Mark R.; Mahoney, Michael J.; Richard, Erik

    2002-01-01

    This work describes transport and thermodynamic processes that control water vapor near the tropopause during the SAGE III-Ozone Loss and Validation Experiment (SOLVE), held during the Arctic 1999/2000 winter season. Aircraft-based water vapor, carbon monoxide, and ozone measurements were analyzed so as to establish how deeply tropospheric air mixes into the Arctic lowermost stratosphere and what the implications are for cloud formation and water vapor removal in this region of the atmosphere. There are three major findings. First, troposphere-to-stratosphere exchange extends into the Arctic stratosphere to about 13 km. Penetration is to similar levels throughout the winter, however, because ozone increases with altitude most rapidly in the early spring, tropospheric air mixes with the highest values of ozone in that season. The effect of this upward mixing is to elevate water vapor mixing ratios significantly above their prevailing stratospheric values of above 5ppmv. Second, the potential for cloud formation in the stratosphere is highest during early spring, with about 20% of the parcels which have ozone values of 300-350 ppbv experiencing ice saturation in a given 10 day period. Third, during early spring, temperatures at the troposphere are cold enough so that 5-10% of parcels experience relative humidities above 100%, even if the water content is as low as 5 ppmv. The implication is that during this period, dynamical processes near the Arctic tropopause can dehydrate air and keep the Arctic tropopause region very dry during early spring.

  9. Processes Controlling Water Vapor in the Winter Arctic Tropopause Region

    NASA Technical Reports Server (NTRS)

    Pfister, Leonhard; Selkirk, Henry B.; Jensen, Eric J.; Podolske, James; Sachse, Glen; Avery, Melody; Schoeberl, Mark R.; Hipskino, R. Stephen (Technical Monitor)

    2001-01-01

    This work describes transport and thermodynamic processes that control water vapor near the tropopause during the SAGE Ozone Loss and Validation Experiment (SOLVE), held during the Arctic 1999-2000 winter season. Aircraft based water vapor, carbon monoxide, and ozone measurements are analyzed so as to establish how deeply tropospheric air mixes into the arctic lower-most stratosphere, and what the implications are for cloud formation and water vapor removal in this region of the atmosphere. There are three major findings. First, troposphere-to- stratosphere exchange extends into the arctic stratosphere to about 13 km. Penetration is to similar levels throughout the winter, however, because ozone increases idly in the early spring, tropospheric air mixes with the highest values of ozone in that season. The effect of this upward mixing is to elevate water vapor mixing ratios significantly above their prevailing stratospheric values of about 5 ppmv. Second, the potential for cloud formation in the stratosphere is highest during early spring, with about 20\\% of the parcels which have ozone values of 300-350ppbv experiencing ice saturation in a given 10 day period. Third, during early Spring temperatures at the tropopause are cold enough so that 5-10\\% of parcels experience relative humidities above 100\\%, even if the water content is as low as 5 ppmv. The implication is that during, this period the arctic tropopause can play an important role in maintaining a very dry upper troposphere during early Spring.

  10. Transport of nitrogen oxides through the winter mesopause in HAMMONIA

    NASA Astrophysics Data System (ADS)

    Meraner, Katharina; Schmidt, Hauke

    2016-03-01

    We analyze the importance of individual transport processes for the winter polar downward transport of nitrogen oxides (NOx) from the thermosphere to the mesosphere. The downward transport of NOx produced by energetic particle precipitation induces chemical alterations in the middle atmosphere and influences ozone chemistry. However, it remains unclear how much each transport process contributes to the downward transport. We use simulations of the atmospheric general circulation and chemistry model HAMMONIA (Hamburg Model of Neutral and Ionized Atmosphere) for the extended winter 2008/2009 with a passive tracer. The model enables us to separate the contributions of advection, eddy and molecular diffusion on the total transport by switching off processes. The results show that molecular diffusion and resolved vertical mixing due to advection effectively transport NOx to the mesosphere. While the impact of molecular diffusion on the transport rapidly decreases below 0.001 hPa, the impact of advection increases. Around the central date of the sudden stratospheric warming in January 2009, advection is strongly enhanced in the thermosphere and mesosphere and the downward transport through the mesopause region is almost entirely driven by advection. Eddy diffusion has limited impact on the transport in the upper mesosphere and negligible impact on the transport in the thermosphere. If eddy diffusion is enhanced as suggested by observations, it can potentially have a larger impact on transport through the mesopause than was previously assumed.

  11. Effects of drought on winter wheat yield in north China during 2012-2100

    NASA Astrophysics Data System (ADS)

    Song, Yanling; Zhao, Yanxia

    2012-08-01

    Winter wheat is one of China's most important staple food crops, and its production is strongly influenced by weather, especially droughts. As a result, the impact of drought on the production of winter wheat is associated with the food security of China. Simulations of future climate for scenarios A2 and A1B provided by GFDL-CM2, MPI_ECHAM5, MRI_CGCM2, NCAR_CCSM3, and UKMO_HADCM3 during 2001-2100 are used to project the influence of drought on winter wheat yields in North China. Winter wheat yields are simulated using the crop model WOFOST (WOrld FOod STudies). Future changes in temperature and precipitation are analyzed. Temperature is projected to increase by 3.9-5.5°C for scenario A2 and by 2.9-5.1°C for scenario A1B, with fairly large interannual variability. Mean precipitation during the growing season is projected to increase by 16.7 and 8.6 mm (10 yr)-1, with spring precipitation increasing by 9.3 and 4.8 mm (10 yr)-1 from 2012-2100 for scenarios A2 and A1B, respectively. For the next 10-30 years (2012-2040), neither the growing season precipitation nor the spring precipitation over North China is projected to increase by either scenario. Assuming constant winter wheat varieties and agricultural practices, the influence of drought induced by short rain on winter wheat yields in North China is simulated using the WOFOST crop model. The drought index is projected to decrease by 9.7% according to scenario A2 and by 10.3% according to scenario A1B during 2012-2100. This indicates that the drought influence on winter wheat yields may be relieved over that period by projected increases in rain and temperature as well as changes in the growth stage of winter wheat. However, drought may be more severe in the near future, as indicated by the results for the next 10-30 years.

  12. Long-term variability in Northern Hemisphere snow cover and associations with warmer winters

    USGS Publications Warehouse

    McCabe, G.J.; Wolock, D.M.

    2010-01-01

    A monthly snow accumulation and melt model is used with gridded monthly temperature and precipitation data for the Northern Hemisphere to generate time series of March snow-covered area (SCA) for the period 1905 through 2002. The time series of estimated SCA for March is verified by comparison with previously published time series of SCA for the Northern Hemisphere. The time series of estimated Northern Hemisphere March SCA shows a substantial decrease since about 1970, and this decrease corresponds to an increase in mean winter Northern Hemisphere temperature. The increase in winter temperature has caused a decrease in the fraction of precipitation that occurs as snow and an increase in snowmelt for some parts of the Northern Hemisphere, particularly the mid-latitudes, thus reducing snow packs and March SCA. In addition, the increase in winter temperature and the decreases in SCA appear to be associated with a contraction of the circumpolar vortex and a poleward movement of storm tracks, resulting in decreased precipitation (and snow) in the low- to mid-latitudes and an increase in precipitation (and snow) in high latitudes. If Northern Hemisphere winter temperatures continue to warm as they have since the 1970s, then March SCA will likely continue to decrease. ?? 2009 Springer Science+Business Media B.V.

  13. Long-term variability in Northern Hemisphere snow cover and associations with warmer winters

    USGS Publications Warehouse

    McCabe, Gregory J.; Wolock, David M.

    2010-01-01

    A monthly snow accumulation and melt model is used with gridded monthly temperature and precipitation data for the Northern Hemisphere to generate time series of March snow-covered area (SCA) for the period 1905 through 2002. The time series of estimated SCA for March is verified by comparison with previously published time series of SCA for the Northern Hemisphere. The time series of estimated Northern Hemisphere March SCA shows a substantial decrease since about 1970, and this decrease corresponds to an increase in mean winter Northern Hemisphere temperature. The increase in winter temperature has caused a decrease in the fraction of precipitation that occurs as snow and an increase in snowmelt for some parts of the Northern Hemisphere, particularly the mid-latitudes, thus reducing snow packs and March SCA. In addition, the increase in winter temperature and the decreases in SCA appear to be associated with a contraction of the circumpolar vortex and a poleward movement of storm tracks, resulting in decreased precipitation (and snow) in the low- to mid-latitudes and an increase in precipitation (and snow) in high latitudes. If Northern Hemisphere winter temperatures continue to warm as they have since the 1970s, then March SCA will likely continue to decrease.

  14. Assessing winter cover crop nutrient uptake efficiency using a water quality simulation model

    NASA Astrophysics Data System (ADS)

    Yeo, I.-Y.; Lee, S.; Sadeghi, A. M.; Beeson, P. C.; Hively, W. D.; McCarty, G. W.; Lang, M. W.

    2014-12-01

    Winter cover crops are an effective conservation management practice with potential to improve water quality. Throughout the Chesapeake Bay watershed (CBW), which is located in the mid-Atlantic US, winter cover crop use has been emphasized, and federal and state cost-share programs are available to farmers to subsidize the cost of cover crop establishment. The objective of this study was to assess the long-term effect of planting winter cover crops to improve water quality at the watershed scale (~ 50 km2) and to identify critical source areas of high nitrate export. A physically based watershed simulation model, Soil and Water Assessment Tool (SWAT), was calibrated and validated using water quality monitoring data to simulate hydrological processes and agricultural nutrient cycling over the period of 1990-2000. To accurately simulate winter cover crop biomass in relation to growing conditions, a new approach was developed to further calibrate plant growth parameters that control the leaf area development curve using multitemporal satellite-based measurements of species-specific winter cover crop performance. Multiple SWAT scenarios were developed to obtain baseline information on nitrate loading without winter cover crops and to investigate how nitrate loading could change under different winter cover crop planting scenarios, including different species, planting dates, and implementation areas. The simulation results indicate that winter cover crops have a negligible impact on the water budget but significantly reduce nitrate leaching to groundwater and delivery to the waterways. Without winter cover crops, annual nitrate loading from agricultural lands was approximately 14 kg ha-1, but decreased to 4.6-10.1 kg ha-1 with cover crops resulting in a reduction rate of 27-67% at the watershed scale. Rye was the most effective species, with a potential to reduce nitrate leaching by up to 93% with early planting at the field scale. Early planting of cover crops (~ 30

  15. Winter warming delays dormancy release, advances budburst, alters carbohydrate metabolism and reduces yield in a temperate shrub.

    PubMed

    Pagter, Majken; Andersen, Uffe Brandt; Andersen, Lillie

    2015-01-01

    Global climate models predict an increase in the mean surface air temperature, with a disproportionate increase during winter. Since temperature is a major driver of phenological events in temperate woody perennials, warming is likely to induce changes in a range of these events. We investigated the impact of slightly elevated temperatures (+0.76 °C in the air, +1.35 °C in the soil) during the non-growing season (October-April) on freezing tolerance, carbohydrate metabolism, dormancy release, spring phenology and reproductive output in two blackcurrant (Ribes nigrum) cultivars to understand how winter warming modifies phenological traits in a woody perennial known to have a large chilling requirement and to be sensitive to spring frost. Warming delayed dormancy release more in the cultivar 'Narve Viking' than in the cultivar 'Titania', but advanced budburst and flowering predominantly in 'Titania'. Since 'Narve Viking' has a higher chilling requirement than 'Titania', this indicates that, in high-chilling-requiring genotypes, dormancy responses may temper the effect of warming on spring phenology. Winter warming significantly reduced fruit yield the following summer in both cultivars, corroborating the hypothesis that a decline in winter chill may decrease reproductive effort in blackcurrant. Elevated winter temperatures tended to decrease stem freezing tolerance during cold acclimation and deacclimation, but it did not increase the risk of freeze-induced damage mid-winter. Plants at elevated temperature showed decreased levels of sucrose in stems of both cultivars and flower buds of 'Narve Viking', which, in buds, was associated with increased concentrations of glucose and fructose. Hence, winter warming influences carbohydrate metabolism, but it remains to be elucidated whether decreased sucrose levels account for any changes in freezing tolerance. Our results demonstrate that even a slight increase in winter temperature may alter phenological traits in

  16. Winter warming as an important co-driver for Betula nana growth in western Greenland during the past century

    PubMed Central

    Hollesen, Jørgen; Buchwal, Agata; Rachlewicz, Grzegorz; Hansen, Birger U; Hansen, Marc O; Stecher, Ole; Elberling, Bo

    2015-01-01

    Growing season conditions are widely recognized as the main driver for tundra shrub radial growth, but the effects of winter warming and snow remain an open question. Here, we present a more than 100 years long Betula nana ring-width chronology from Disko Island in western Greenland that demonstrates a highly significant and positive growth response to both summer and winter air temperatures during the past century. The importance of winter temperatures for Betula nana growth is especially pronounced during the periods from 1910–1930 to 1990–2011 that were dominated by significant winter warming. To explain the strong winter importance on growth, we assessed the importance of different environmental factors using site-specific measurements from 1991 to 2011 of soil temperatures, sea ice coverage, precipitation and snow depths. The results show a strong positive growth response to the amount of thawing and growing degree-days as well as to winter and spring soil temperatures. In addition to these direct effects, a strong negative growth response to sea ice extent was identified, indicating a possible link between local sea ice conditions, local climate variations and Betula nana growth rates. Data also reveal a clear shift within the last 20 years from a period with thick snow depths (1991–1996) and a positive effect on Betula nana radial growth, to a period (1997–2011) with generally very shallow snow depths and no significant growth response towards snow. During this period, winter and spring soil temperatures have increased significantly suggesting that the most recent increase in Betula nana radial growth is primarily triggered by warmer winter and spring air temperatures causing earlier snowmelt that allows the soils to drain and warm quicker. The presented results may help to explain the recently observed ‘greening of the Arctic’ which may further accelerate in future years due to both direct and indirect effects of winter warming. PMID:25788025

  17. Habitat Suitability Index Models: Lesser Scaup (Wintering)

    USGS Publications Warehouse

    Mulholland, Rosemarie

    1985-01-01

    A review and synthesis of existing information were used to develop a model for evaluating wintering habitat quality for the lesser scaup (Aythya affinis). The model is scaled to produce an index of habitat suitability between 0.0 (unsuitable habitat) to 1.0 (optimal habitat) for Southern Atlantic and Gulf of Mexico coastal areas of the continental United States. Habitat suitability indices are designed for use with the Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service Guidelines for model application and techniques for measuring model variables are provided.

  18. Winter Mesospheric Thermal Structure over Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Qiao, Shuai; Pan, Weilin; Lü, Daren

    2016-06-01

    A mobile Rayleigh temperature lidar was deployed in Golmud (36.25°N 94.54°E), Qinghai in China for making measurements of mesosphere temperature from 55 up to 90 km. The mesospheric thermal structure was obtained during the winter seasons of Year 2013 and Year 2014. At the altitude of 57~79 km, lidar temperatures were much colder than the MSIS-00 model predictions. However, in the lower mesosphere region, lidar measurements were in reasonable agreement compared with the TIMED-SABER satellite data.

  19. Drifting invertebrates, stomach contents, and body conditions of juvenile rainbow trout from fall through winter in a Wyoming tailwater

    USGS Publications Warehouse

    Simpkins, D.G.; Hubert, W.A.

    2000-01-01

    We investigated the availability of drifting invertebrates and the stomach contents and body conditions of stocked (hatchery) and naturally spawned (wild) juvenile (20-25 cm total length) rainbow trout from fall through winter in the Big Horn River downstream from Boysen Dam in Wyoming. When the density and biomass of drifting invertebrates declined with water temperature during the fall, stomach contents and body conditions substantially decreased among both wild and stocked fish. During the coldest portion of the winter, the density of small drifting invertebrates increased as did the body conditions of both wild and hatchery trout. We suggest that the perceived increase in body conditions during late winter was due to survival of fish with higher body conditions and not growth of fish from fall to late winter.

  20. Winter effect on soil microorganisms under different tillage and phosphorus management practices in eastern Canada.

    PubMed

    Shi, Yichao; Lalande, Roger; Hamel, Chantal; Ziadi, Noura

    2015-05-01

    Determining how soil microorganisms respond to crop management systems during winter could further our understanding of soil phosphorus (P) transformations. This study assessed the effects of tillage (moldboard plowing or no-till) and P fertilization (0, 17.5, or 35 kg P·ha(-1)) on soil microbial biomass, enzymatic activity, and microbial community structure in winter, in a long-term (18 years) corn (Zea mays L.) and soybean (Glycine max L.) rotation established in 1992 in the province of Quebec, Canada. Soil samples were collected at 2 depths (0-10 and 10-20 cm) in February 2010 and 2011 after the soybean and the corn growing seasons, respectively. Winter conditions increased the amounts of soil microbial biomasses but reduced the overall enzymatic activity of the soil, as compared with fall levels after corn. P fertilization had a quadratic effect on the amounts of total, bacterial, arbuscular mycorrhizal fungi phospholipid fatty acid markers after corn but not after soybean. The soil microbial community following the soybean and the corn crops in winter had a different structure. These findings suggest that winter conditions and crop-year could be important factors affecting the characteristics of the soil microbial community under different tillage and mineral P fertilization. PMID:25776569