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. 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.

  4. Inter-annual Variability of Snowfall in the Lower Peninsula of Michigan, USA

    NASA Astrophysics Data System (ADS)

    Meng, L.

    2016-12-01

    Winter snowfall, particularly lake-effect snowfall, impacts all aspects of Michigan life in the wintertime, from motorsports and tourism to impacting the day-to-day lives of residents. Understanding the inter-annual variability of winter snowfall will provide sound basis for local community safety management and improve weather forecasting. This study attempts to understand the trend in winter snowfall and the influencing factors of winter snowfall variability in the Lower Peninsula of Michigan (LPM) using station snowfall measurements and statistical analysis. Our study demonstrates that snowfall has significantly increased from 1932 to 2015. Correlation analysis suggests that regionally average air temperatures have a strong negative relationship with snowfall in LPM. On average, approximately 27% of inter-annual variability in snowfall can be explained by regionally average air temperatures. ENSO events are also negatively related to snowfall in LPM and can explain 8% of inter-annual variability. North Atlantic Oscillation (NAO) does not have strong influence on snowfall. Composite analysis demonstrates that on annual basis, more winter snowfall occurs during the years with higher maximum ice cover (MIC) than during the years with lower MIC in Lake Michigan. Higher MIC is often associated with lower air temperatures which are negatively related to winter snowfall. This study could provide insight on future snow related climate model improvement and weather forecasting.

  5. 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.

  6. Future projections of total snowfall and heavy snowfall in Japan simulated by large ensemble regional climate simulations.

    NASA Astrophysics Data System (ADS)

    Kawase, H.; Sasaki, H.; Murata, A.; Nosaka, M.; Ito, R.; Dairaku, K.; Sasai, T.; Yamazaki, T.; Sugimoto, S.; Watanabe, S.; Fujita, M.; Kawazoe, S.; Okada, Y.; Ishii, M.; Mizuta, R.; Takayabu, I.

    2017-12-01

    We performed large ensemble climate experiments to investigate future changes in extreme weather events using Meteorological Research Institute-Atmospheric General Circulation Model (MRI-AGCM) with about 60 km grid spacing and Non-Hydrostatic Regional Climate Model with 20 km grid spacing (NHRCM20). The global climate simulations are prescribed by the past and future sea surface temperature (SST). Two future climate simulations are conducted so that the global-mean surface air temperature rise 2 K and 4 K from the pre-industrial period. The non-warming simulations are also conducted by MRI-AGCM and NHRCM20. We focus on the future changes in snowfall in Japan. In winter, the Sea of Japan coast experiences heavy snowfall due to East Asian winter monsoon. The cold and dry air from the continent obtains abundant moisture from the warm Sea of Japan, causing enormous amount of snowfall especially in the mountainous area. The NHRCM20 showed winter total snowfall decreases in the most parts of Japan. In contrast, extremely heavy daily snowfall could increase at mountainous areas in the Central Japan and Northern parts of Japan when strong cold air outbreak occurs and the convergence zone appears over the Sea of Japan. The warmer Sea of Japan in the future climate could supply more moisture than that in the present climate, indicating that the cumulus convections could be enhanced around the convergence zone in the Sea of Japan. However, the horizontal resolution of 20 km is not enough to resolve Japan`s complex topography. Therefore, dynamical downscaling with 5 km grid spacing (NHRCM05) is also conducted using NHRCM20. The NHRCM05 does a better job simulating the regional boundary of snowfall and shows more detailed changes in future snowfall characteristics. The future changes in total and extremely heavy snowfall depend on the regions, elevations, and synoptic conditions around Japan.

  7. Analysis and Comparison of the Temperature and Snowfall Conditions for the Winters of 2014/15 and 2015/16 at Three Ski Resorts in British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Pidwirny, M. J.; Pedersen, S.

    2016-12-01

    accumulations decreased by about 79% for Cypress, 57% for Whistler, and 9% for Big White in 2014/15 when compared to 2012/13. In contrast, the winter of 2015/16 saw snowfall increases of 10% for Cypress, 35% for Whistler, and 97% for Big White relative to 2012/13. Together, the colder temperatures and higher snowfall produced better than expected ski conditions in 2015/16.

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

    NASA Astrophysics Data System (ADS)

    Winkelmann, Ricarda; Levermann, Anders; Martin, Maria A.; Frieler, Katja

    2013-04-01

    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. 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, 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.

  9. 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.

  10. Snow cover and snowfall impact corticosterone and immunoglobulin a levels in a threatened steppe bird.

    PubMed

    Liu, Gang; Hu, Xiaolong; Kessler, Aimee Elizabeth; Gong, Minghao; Wang, Yihua; Li, Huixin; Dong, Yuqiu; Yang, Yuhui; Li, Linhai

    2018-05-15

    Birds use both the corticosterone stress response and immune system to meet physiological challenges during exposure to adverse climatic conditions. To assess the stress level and immune response of the Asian Great Bustard during conditions of severe winter weather, we measured fecal corticosterone (CORT) and Immunoglobulin A (IgA) before and after snowfall in a low snow cover year (2014) and a high snow cover year (2015). A total of 239 fecal samples were gathered from individuals in Tumuji Nature Reserve, located in eastern Inner Mongolia, China. We observed high CORT levels that rose further after snowfall both in high and low snow cover years. IgA levels increased significantly after snowfall in the low snow cover year, but decreased after snowfall in the high snow cover year. These results suggest that overwintering Asian Great Bustards are subjected to climatic stress during severe winter weather, and the hypothalamic-pituitary-adrenal axis and immune system react to this challenge. Extreme levels of stress, such as snowfall in already prolonged and high snow cover conditions may decrease immune function. Supplemental feeding should be considered under severe winter weather conditions for this endangered subspecies. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. 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.

  12. 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

  13. Possible Role of Hadley Circulation Strengthening in Interdecadal Intensification of Snowfalls Over Northeastern China Under Climate Change

    NASA Astrophysics Data System (ADS)

    Zhou, Botao; Wang, Zunya; Shi, Ying

    2017-11-01

    This article revealed that strengthening of winter Hadley circulation in the context of climate change may partially contribute to interdecadal increasing of snowfall intensity over northeastern China in recent decades. This hypothesis is well supported by the process-based linkage between Hadley circulation and atmospheric circulations over the Asian-Pacific region on the interdecadal time scale. The strengthening of winter Hadley circulation corresponds to a weakening of the Siberian high, an eastward shifting of the Aleutian low, a reduction of the East Asian trough, and anomalous southwesterly prevailing over northeastern China. These atmospheric situations weaken the East Asian winter monsoon and lead to an increase of air temperature over northeastern China. Increased local evaporation due to the increase of air temperature, concurrent with more water vapor transported from the Pacific Ocean, can significantly enhance atmospheric water vapor content in the target region. Meanwhile, the ascending of airflows is also strengthened over northeastern China. All of these provide favorable interdecadal backgrounds for the occurrence of intense snowfalls, and thus, snowfall intensity is intensified over northeastern China after the 1980s. Further analysis suggests that the circum-Pacific-like teleconnection pattern may play an important role in connecting Hadley circulation strengthening signal and atmospheric circulation anomalies favoring interdecadal intensification of snowfalls over northeastern China.

  14. Temperature and Snowfall in Western Queen Maud Land Increasing Faster Than Climate Model Projections

    NASA Astrophysics Data System (ADS)

    Medley, B.; McConnell, J. R.; Neumann, T. A.; Reijmer, C. H.; Chellman, N.; Sigl, M.; Kipfstuhl, S.

    2018-02-01

    East Antarctic Ice Sheet (EAIS) mass balance is largely driven by snowfall. Recently, increased snowfall in Queen Maud Land led to years of EAIS mass gain. It is difficult to determine whether these years of enhanced snowfall are anomalous or part of a longer-term trend, reducing our ability to assess the mitigating impact of snowfall on sea level rise. We determine that the recent snowfall increases in western Queen Maud Land (QML) are part of a long-term trend (+5.2 ± 3.7% decade-1) and are unprecedented over the past two millennia. Warming between 1998 and 2016 is significant and rapid (+1.1 ± 0.7°C decade-1). Using these observations, we determine that the current accumulation and temperature increases in QML from an ensemble of global climate simulations are too low, which suggests that projections of the QML contribution to sea level rise are potentially overestimated with a reduced mitigating impact of enhanced snowfall in a warming world.

  15. Temperature and Snowfall in Western Queen Maud Land Increasing Faster than Climate Model Projections

    NASA Technical Reports Server (NTRS)

    Medley, B.; McConnell, J. R.; Neumann, T. A.; Reijmer, C. H.; Chellman, N.; Sigl, M.; Kipfstuhl, S.

    2017-01-01

    East Antarctic Ice Sheet (EAIS) mass balance is largely driven by snowfall. Recently, increased snowfall in Queen Maud Land led to years of EAIS mass gain. It is difficult to determine whether these years of enhanced snowfall are anomalous or part of a longer-term trend, reducing our ability to assess the mitigating impact of snowfall on sea level rise. We determine that the recent snowfall increases in western Queen Maud Land (QML) are part of a long-term trend (+5.2 +/- 3.7% decade(exp -1)) and are unprecedented over the past two millennia. Warming between 1998 and 2016 is significant and rapid (+1.1 +/- 0.7 C decade(exp -1)). Using these observations, we determine that the current accumulation and temperature increases in QML from an ensemble of global climate simulations are too low, which suggests that projections of the QML contribution to sea level rise are potentially overestimated with a reduced mitigating impact of enhanced snowfall in a warming world.

  16. Increases in wintertime PM2.5 sodium and chloride linked to snowfall and road salt application

    NASA Astrophysics Data System (ADS)

    Kolesar, Katheryn R.; Mattson, Claire N.; Peterson, Peter K.; May, Nathaniel W.; Prendergast, Rashad K.; Pratt, Kerri A.

    2018-03-01

    The application of salts and salty brines to roads is common practice during the winter in many urban environments. Road salts can become aerosolized, thereby injecting sodium and chloride particulate matter (PM) into the atmosphere. Here, data from the United States Environmental Protection Agency Chemical Speciation Monitoring Network were used to assess temporal trends of sodium and chloride PM2.5 (PM < 2.5 μm) at 25 locations across the United States to investigate the ubiquity of road salt aerosols. Sodium and chloride PM2.5 concentrations were an average of three times higher in the winter, as compared to the summer, for locations with greater than 25 cm of average annual snowfall. Winter urban chloride PM2.5 concentrations attributed to road salt can even sometimes rival those of coastal sea spray aerosol-influenced sites. In most snow-influenced cities, chloride and sodium PM2.5 concentrations were positively correlated with snowfall; however, this relationship is complicated by differences in state and local winter maintenance practices. This study highlights the ubiquity of road salt aerosols in the United States and their potential impact on wintertime urban air quality, particularly due to the potential for multiphase reactions to liberate chlorine from the particle-phase. Since road salt application is a common practice in wintertime urban environments across the world, it is imperative that road salt application emissions, currently not included in inventories, and its impacts be investigated through measurements and modeling.

  17. Future snowfall in the Alps: projections based on the EURO-CORDEX regional climate models

    NASA Astrophysics Data System (ADS)

    Frei, Prisco; Kotlarski, Sven; Liniger, Mark A.; Schär, Christoph

    2018-01-01

    Twenty-first century snowfall changes over the European Alps are assessed based on high-resolution regional climate model (RCM) data made available through the EURO-CORDEX initiative. Fourteen different combinations of global and regional climate models with a target resolution of 12 km and two different emission scenarios are considered. As raw snowfall amounts are not provided by all RCMs, a newly developed method to separate snowfall from total precipitation based on near-surface temperature conditions and accounting for subgrid-scale topographic variability is employed. The evaluation of the simulated snowfall amounts against an observation-based reference indicates the ability of RCMs to capture the main characteristics of the snowfall seasonal cycle and its elevation dependency but also reveals considerable positive biases especially at high elevations. These biases can partly be removed by the application of a dedicated RCM bias adjustment that separately considers temperature and precipitation biases.

    Snowfall projections reveal a robust signal of decreasing snowfall amounts over most parts of the Alps for both emission scenarios. Domain and multi-model mean decreases in mean September-May snowfall by the end of the century amount to -25 and -45 % for representative concentration pathway (RCP) scenarios RCP4.5 and RCP8.5, respectively. Snowfall in low-lying areas in the Alpine forelands could be reduced by more than -80 %. These decreases are driven by the projected warming and are strongly connected to an important decrease in snowfall frequency and snowfall fraction and are also apparent for heavy snowfall events. In contrast, high-elevation regions could experience slight snowfall increases in midwinter for both emission scenarios despite the general decrease in the snowfall fraction. These increases in mean and heavy snowfall can be explained by a general increase in winter precipitation and by the fact that, with increasing temperatures

  18. 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

  19. Winter is losing its cool

    NASA Astrophysics Data System (ADS)

    Feng, S.

    2017-12-01

    Winter seasons have significant societal impacts across all sectors ranging from direct human health to ecosystems, transportation, and recreation. This study quantifies the severity of winter and its spatial-temporal variations using a newly developed winter severity index and daily temperature, snowfall and snow depth. The winter severity and the number of extreme winter days are decreasing across the global terrestrial areas during 1901-2015 except the southeast United States and isolated regions in the Southern Hemisphere. These changes are dominated by winter warming, while the changes in daily snowfall and snow depth played a secondary role. The simulations of multiple CMIP5 climate models can well capture the spatial and temporal variations of the observed changes in winter severity and extremes during 1951-2005. The models are consistent in projecting a future milder winter under various scenarios. The winter severity is projected to decrease 60-80% in the middle-latitude Northern Hemisphere under the business-as-usual scenario. The winter arrives later, ends earlier and the length of winter season will be notably shorter. The changes in harsh winter in the polar regions are weak, mainly because the warming leads to more snowfall in the high latitudes.

  20. Global snowfall: A combined CloudSat, GPM, and reanalysis perspective.

    NASA Astrophysics Data System (ADS)

    Milani, Lisa; Kulie, Mark S.; Skofronick-Jackson, Gail; Munchak, S. Joseph; Wood, Norman B.; Levizzani, Vincenzo

    2017-04-01

    Quantitative global snowfall estimates derived from multi-year data records will be presented to highlight recent advances in high latitude precipitation retrievals using spaceborne observations. More specifically, the analysis features the 2006-2016 CloudSat Cloud Profiling Radar (CPR) and the 2014-2016 Global Precipitation (GPM) Microwave Imager (GMI) and Dual-frequency Precipitation Radar (DPR) observational datasets and derived products. The ERA-Interim reanalysis dataset is also used to define the meteorological context and an independent combined modeling/observational evaluation dataset. An overview is first provided of CloudSat CPR-derived results that have stimulated significant recent research regarding global snowfall, including seasonal analyses of unique snowfall modes. GMI and DPR global annual snowfall retrievals are then evaluated against the CloudSat estimates to highlight regions where the datasets provide both consistent and diverging snowfall estimates. A hemispheric seasonal analysis for both datasets will also be provided. These comparisons aim at providing a unified global snowfall characterization that leverages the respective instrument's strengths. Attention will also be devoted to regions around the globe that experience unique snowfall modes. For instance, CloudSat has demonstrated an ability to effectively discern snowfall produced by shallow cumuliform cloud structures (e.g., lake/ocean-induced convective snow produced by air/water interactions associated with seasonal cold air outbreaks). The CloudSat snowfall database also reveals prevalent seasonal shallow cumuliform snowfall trends over climate-sensitive regions like the Greenland Ice Sheet. Other regions with unique snowfall modes, such as the US East Coast winter storm track zone that experiences intense snowfall rates directly associated with strong low pressure systems, will also be highlighted to demonstrate GPM's observational effectiveness. Linkages between CloudSat and GPM

  1. 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.

  2. 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

  3. Variation trend of snowfall in the Kamikochi region of the Japanese Alps

    NASA Astrophysics Data System (ADS)

    Suzuki, K.

    2017-12-01

    The Japanese Alps experience exceptionally heavy snowfall, extreme even by global standards, and in spring and summer the melting snow becomes a valuable water resource. The snow effectively acts as a natural dam when it accumulates in watersheds during winter. However, there have been no observations of the amount of snow in high-altitude regions of Japan. Therefore, we cannot discuss the effect of global warming on the change in the amount of snow in these regions based on direct observation data. We were, however, able to obtain climatic and hydrologic data for high-altitude sites in the Japanese Alps, and discuss the variations in these conditions in the Kamikochi region (altitude 1490 m-3190 m) of the Japanese Alps over a 68-year period using these observed data. No long-term trends are observed in the annual mean, maximum, or minimum temperatures at Taisho-ike from 1945 to 2012; the total annual precipitation shows a statistically significant decreasing trend. The annual total snowfall at Taisho-ike from 1969 to 2012 shows a statistically significant increasing trend. The annual total runoff of the Azusa River from 1945 to 2012 shows a statistically significant increasing trend, as does the snowmelt runoff to the river (which occurs from May to July). We can thus conclude that the annual snowfall in the Azusa River catchment has increased in recent years.

  4. 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

  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. An evaluation of the Wyoming Gauge System for snowfall measurement

    USGS Publications Warehouse

    Yang, Daqing; Kane, Douglas L.; Hinzman, Larry D.; Goodison, Barry E.; Metcalfe, John R.; Louie, Paul Y.T.; Leavesley, George H.; Emerson, Douglas G.; Hanson, Clayton 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.

  7. A Linkage of Recent Arctic Summer Sea Ice and Snowfall Variability of Japan

    NASA Astrophysics Data System (ADS)

    Iwamoto, K.; Honda, M.; Ukita, J.

    2014-12-01

    In spite of its mid-latitude location, Japan has a markedly high amount of snowfall, which owes much to the presence of cold air-break from Siberia and thus depends on the strength of the Siberian high and the Aleutian low. With this background this study examines the relationship between interannual variability and spatial patterns of snowfall in Japan with large-scale atmospheric and sea ice variations. The lag regression map of the winter snowfall in Japan on the time series of the Arctic SIE from the preceding summer shows a seesaw pattern in the snowfall, suggesting an Arctic teleconnection to regional weather. From the EOF analyses conducted on the snowfall distribution in Japan, we identify two modes with physical significance. The NH SIC and SLP regressed on PC1 show a sea ice reduction in the Barents and Kara Seas and anomalous strength of the Siberia high as discussed in Honda et al. (2009) and other studies, which support the above notion that the snowfall variability of Japan is influenced by Arctic sea ice conditions. Another mode is related to the AO/NAO and the hemispheric scale double sea-ice seesaw centered over the sub-Arctic region: one between the Labrador and Nordic Seas in the Atlantic and the other between the Okhotsk and Bering Seas from the Pacific as discussed in Ukita et al. (2007). Together, observations point to a significant role of the sea-ice in determining mid-latitude regional climate and weather patterns.

  8. 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.

  9. Characterization of snowfall properties at high-latitude sites through use of a combined Multi-Angle Snow Camera (MASC) and radar approach

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    Estimates of snowfall rate derived from radar reflectivities alone are non-unique, as different combinations of snowfall rates and snowflake microphysical properties can conspire to produce nearly identical radar reflectivity signatures. Such ambiguities can result in retrieval uncertainties on the order of 100-200% for individual events. Here, we use observations of snowflake particle size distribution, fallspeed, and habit from the Multi-Angle Snow Camera (MASC) to constrain estimates of snowfall derived from radar reflectivities. MASC measurements of microphysical properties and uncertainties are introduced into a modified form of the optimal-estimation CloudSat snowfall algorithm (2C-SNOW-PROFILE) via the a priori guess and variance terms. Initial results focus on the MASC and Ka-band Zenith Radar (KaZR) measurements at the ARM NSA Barrow Climate Facility site. Use of MASC fallspeed, MASC PSD, and a CloudSat particle model as base assumptions resulted in retrieved total accumulations with a -17% difference relative to nearby National Weather Service observations averaged over five snow events. Use of different but reasonable combinations of retrieval assumptions resulted in estimated snowfall accumulations with differences ranging from -63% to + 86% for the same storm events. Retrieved snowfall rates were particularly sensitive to assumed fallspeed and habit, suggesting that MASC measurements may provide a path forward in reducing the non-uniqueness of the snowfall retrieval problem. Preliminary results also will be presented for the deployment of the MASC, MicroRain Radar (MRR), and Precipitation Imaging Package (PIP) to Haukeliseter, Norway during winter season 2016-17. These instruments will then be deployed to northern Sweden for winter 2017-18. It is hoped more accurate knowledge of snowfall properties dependent upon location and meteorological conditions will be useful for both weather and climate applications.

  10. 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)

    Koh, D.

    2016-12-01

    The Yeongdong region in Korea has frequent heavy snowfall in winter, which usually results in societal and economic damages such as collapses of the greenhouse and the temporary building due to heavy snowfall weights and traffic accidents due to snow-slippery road condition. Therefore we have conducted an intensive measurement campaign of `Experiment on Snow Storms At Yeongdong (ESSAY)' using radiosonde soundings, several remote sensors and a digital camera with a magnifier for taking a photograph of snowfall crystals in the region. The analysis period is mainly limited to every winter from 2014 to 2016The typical synoptic situation for the heavy snowfall is Low pressure system passing by the far South of the Korean peninsula along with the Siberian High extending to northern Japan, leading to the northeasterly or easterly flows frequently accompanied by the long-lasting snowfall in the Yeongdong region. The snow crystal habits observed in the ESSAY campaign are mainly dendrite, consisting of about 70% of the entire habits, indicative of relatively warmer East Sea effect. Meanwhile, the rimed habits are frequently captured specifically when two-layered clouds are observed. The homogeneous habit such as dendrite is shown in case of shallow clouds with its thickness below 500 m, whereas various habits are captured such as graupel, dendrites, rimed dendrites, etc in the thicker cloud with its thickness greater than 1.5 km. The association of snow crystal habits with temperature and supersaturation in the cloud will be more discussed.

  11. Enhancing our Understanding of Snowfall Modes with Ground-Based Observations

    NASA Astrophysics Data System (ADS)

    Pettersen, C.; Kulie, M.; Petersen, W. A.; Bliven, L. F.; Wood, N.

    2016-12-01

    Snowfall can be broadly categorized into deep and shallow events based on the vertical distribution of the precipitating ice. Remotely sensed data refine these precipitation categories and aid in discerning the underlying macro- and microphysical mechanisms. The unique patterns in the remotely sensed instruments observations can potentially connect distinct modes of snowfall to specific processes. Though satellites can observe and recognize these patterns in snowfall, these measurements are limited - particularly in cases of shallow and light precipitation, as the snow may be too close to the surface or below the detection limits of the instrumentation. By enhancing satellite measurements with ground-based instrumentation, whether with limited-term field campaigns or long-term strategic sites, we can further our understanding and assumptions about different snowfall modes and how they are measured from spaceborne instruments. Presented are three years of data from a ground-based instrument suite consisting of a MicroRain Radar (MRR; optimized for snow events) and a Precipitation Imaging Package (PIP). These instruments are located at the Marquette, Michigan National Weather Service Weather Forecast Office to: a) use coincident meteorological measurements and observations to enhance our understanding of the thermodynamic drivers and b) showcase these instruments in an operational setting to enhance forecasts of shallow snow events. Three winters of MRR and PIP measurements are partitioned, based on meteorological surface observations, into two-dimensional histograms of reflectivity and particle size distribution data. These statistics improve our interpretation of deep versus shallow precipitation. Additionally, these statistical techniques are applied to similar datasets from Global Precipitation Measurement field campaigns for further insight into cloud and precipitation macro- and microphysical processes.

  12. 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

  13. 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.

  14. Improving Satellite-Based Snowfall Estimation: A New Method for Classifying Precipitation Phase and Estimating Snowfall Rate

    NASA Astrophysics Data System (ADS)

    Sims, Elizabeth M.

    In order to study the impact of climate change on the Earth's hydrologic cycle, global information about snowfall is needed. To achieve global measurements of snowfall over both land and ocean, satellites are necessary. While satellites provide the best option for making measurements on a global scale, the task of estimating snowfall rate from these measurements is a complex problem. Satellite-based radar, for example, measures effective radar reflectivity, Ze, which can be converted to snowfall rate, S, via a Ze-S relation. Choosing the appropriate Ze-S relation to apply is a complicated problem, however, because quantities such as particle shape, size distribution, and terminal velocity are often unknown, and these quantities directly affect the Ze-S relation. Additionally, it is important to correctly classify the phase of precipitation. A misclassification can result in order-of-magnitude errors in the estimated precipitation rate. Using global ground-based observations over multiple years, the influence of different geophysical parameters on precipitation phase is investigated, with the goal of obtaining an improved method for determining precipitation phase. The parameters studied are near-surface air temperature, atmospheric moisture, low-level vertical temperature lapse rate, surface skin temperature, surface pressure, and land cover type. To combine the effects of temperature and moisture, wet-bulb temperature, instead of air temperature, is used as a key parameter for separating solid and liquid precipitation. Results show that in addition to wet-bulb temperature, vertical temperature lapse rate also affects the precipitation phase. For example, at a near-surface wet-bulb temperature of 0°C, a lapse rate of 6°C km-1 results in an 86 percent conditional probability of solid precipitation, while a lapse rate of -2°C km-1 results in a 45 percent probability. For near-surface wet-bulb temperatures less than 0°C, skin temperature affects precipitation

  15. 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.

  16. Trends in snowfall versus rainfall in the western United States

    USGS Publications Warehouse

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

    2006-01-01

    The water resources of the western United States depend heavily on snowpack to store part of the wintertime precipitation into the drier summer months. A well-documented shift toward earlier runoff in recent decades has been attributed to 1) more precipitation falling as rain instead of snow and 2) earlier snowmelt. The present study addresses the former, documenting a regional trend toward smaller ratios of winter-total snowfall water equivalent (SFE) to winter-total precipitation (P) during the period 1949-2004. The trends toward reduce d SFE are a response to warming across the region, with the most significant reductions occurring where winter wet-day minimum temperatures, averaged over the study period, were warmer than -5??C. Most SFE reductions were associated with winter wet-day temperature increases between 0?? and +3??C over the study period. Warmings larger than this occurred mainly at sites where the mean temperatures were cool enough that the precipitation form was less susceptible to warming trends. The trends toward reduced SFE/P ratios w ere most pronounced in March regionwide and in January near the West Coast, corresponding, to widespread warming in these months. While mean temperatures in March were sufficiently high to allow the warming, trend to produce SFE/P declines across the study region, mean January temperatures were cooler. with the result that January SFE/P impacts were restricted to the lower elevations near the West Coast. Extending the analysis back to 1920 sho ws that although the trends presented here may be partially attributable to interdecadal climate variability associated with the Pacific decadal oscillation. they also appear to result from still longer-term climate shifts.

  17. The sensitivity of snowfall to weather states over Sweden

    NASA Astrophysics Data System (ADS)

    Norin, Lars; Devasthale, Abhay; L'Ecuyer, Tristan S.

    2017-09-01

    For a high-latitude country like Sweden snowfall is an important contributor to the regional water cycle. Furthermore, snowfall impacts surface properties, affects atmospheric thermodynamics, has implications for traffic and logistics management, disaster preparedness, and also impacts climate through changes in surface albedo and turbulent heat fluxes. For Sweden it has been shown that large-scale atmospheric circulation patterns, or weather states, are important for precipitation variability. Although the link between atmospheric circulation patterns and precipitation has been investigated for rainfall there are no studies focused on the sensitivity of snowfall to weather states over Sweden.In this work we investigate the response of snowfall to eight selected weather states. These weather states consist of four dominant wind directions together with cyclonic and anticyclonic circulation patterns and enhanced positive and negative phases of the North Atlantic Oscillation. The presented analysis is based on multiple data sources, such as ground-based radar measurements, satellite observations, spatially interpolated in situ observations, and reanalysis data. The data from these sources converge to underline the sensitivity of falling snow over Sweden to the different weather states.In this paper we examine both average snowfall intensities and snowfall accumulations associated with the different weather states. It is shown that, even though the heaviest snowfall intensities occur during conditions with winds from the south-west, the largest contribution to snowfall accumulation arrives with winds from the south-east. Large differences in snowfall due to variations in the North Atlantic Oscillation are shown as well as a strong effect of cyclonic and anticyclonic circulation patterns. Satellite observations are used to reveal the vertical structures of snowfall during the different weather states.

  18. Winter temperature conditions (1670-2010) reconstructed from varved sediments, western Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Amann, Benjamin; Lamoureux, Scott F.; Boreux, Maxime P.

    2017-09-01

    Advances in paleoclimatology from the Arctic have provided insights into long-term climate conditions. However, while past annual and summer temperature have received considerable research attention, comparatively little is known about winter paleoclimate. Arctic winter is of special interest as it is the season with the highest sensitivity to climate change, and because it differs substantially from summer and annual measures. Therefore, information about past changes in winter climate is key to improve our knowledge of past forced climate variability and to reduce uncertainty in climate projections. In this context, Arctic lakes with snowmelt-fed catchments are excellent potential winter climate archives. They respond strongly to snowmelt-induced runoff, and indirectly to winter temperature and snowfall conditions. To date, only a few well-calibrated lake sediment records exist, which appear to reflect site-specific responses with differing reconstructions. This limits the possibility to resolve large-scale winter climate change prior the instrumental period. Here, we present a well-calibrated quantitative temperature and snowfall record for the extended winter season (November through March; NDJFM) from Chevalier Bay (Melville Island, NWT, Canadian Arctic) back to CE 1670. The coastal embayment has a large catchment influenced by nival terrestrial processes, which leads to high sedimentation rates and annual sedimentary structures (varves). Using detailed microstratigraphic analysis from two sediment cores and supported by μ-XRF data, we separated the nival sedimentary units (spring snowmelt) from the rainfall units (summer) and identified subaqueous slumps. Statistical correlation analysis between the proxy data and monthly climate variables reveals that the thickness of the nival units can be used to predict winter temperature (r = 0.71, pc < 0.01, 5-yr filter) and snowfall (r = 0.65, pc < 0.01, 5-yr filter) for the western Canadian High Arctic over the last

  19. Vegetation response to the 2016-2017 extreme Sierra Nevada snowfall event using multitemporal terrestrial laser scanning: initial results

    NASA Astrophysics Data System (ADS)

    Greenberg, J. A.; Hou, Z.; Ramirez, C.; Hart, R.; Marchi, N.; Parra, A. S.; Gutierrez, B.; Tompkins, R.; Harpold, A.; Sullivan, B. W.; Weisberg, P.

    2017-12-01

    The Sierra Nevada Mountains experienced record-breaking snowfall during the 2016-2017 winter after a prolonged period of drought. We hypothesized that at lower elevations, the increased snowmelt would result in a significant increase in biomass across vegetation strata, but at higher elevations, the snowpack would result in a diminished growing season, and yield a suppression of growth rates particularly in the understory vegetation. To test these hypotheses, we sampled sites across the Plumas National Forest and Lake Tahoe Basin using a terrestrial laser scanner (TLS) in the early growing season, and then rescanned these sites in the late growing season. Herein, we present initial, early results from this analysis, focusing on the biomass and height changes in trees.

  20. 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

  1. Some mean atmospheric characteristics for snowfall occurrences in southern Brazil

    NASA Astrophysics Data System (ADS)

    Mintegui, Jéssica Melo; Puhales, Franciano Scremin; Boiaski, Nathalie Tissot; Nascimento, Ernani de Lima; Anabor, Vagner

    2018-01-01

    Snowfall is considered a natural disaster in southern Brazil, where a little infrastructure exists up to prevent against the damage it induces, making snowfall forecast a matter of great interest in this region. The present article aims to describe the mean behavior of low, mid, and high atmospheric levels during snowfall occurrences in southern Brazil. Sea-level pressure (SLP), 1000-500 hPa atmospheric thickness, geopotential height at 500 hPa, and wind speed at 200 hPa have been analyzed. One hundred and ninety-six snowfall records from the conventional surface meteorological stations have been selected for the period from 1979 to 2015. The surface synoptic pattern associated with snowfall occurrences has been obtained from ERA-Interim reanalysis data with horizontal spatial resolution of 0.75° × 0.75° and temporal resolution of 12 h. SLP fields show a high-pressure transient system displacement from the Pacific Ocean to northeastern Argentina. In addition, it is possible to relate snowfall with displacement of a low-pressure system on the coast of southern Brazil. Thickness fields indicate shallow cold air mass intrusions one day before snowfall. Such a cold air continues moving towards low latitudes during consecutive snowfall days and it may be responsible for frost events in climatologically warm regions. Finally, mid and high atmospheric levels show an eastward propagating wave amplified by the Andes.

  2. Circulation patterns governing October snowfalls in southern Siberia

    NASA Astrophysics Data System (ADS)

    Bednorz, Ewa; Wibig, Joanna

    2017-04-01

    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.

  3. 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.

  4. Quantifying the effect of riming on snowfall using ground-based observations

    NASA Astrophysics Data System (ADS)

    Moisseev, Dmitri; von Lerber, Annakaisa; Tiira, Jussi

    2017-04-01

    Ground-based observations of ice particle size distribution and ensemble mean density are used to quantify the effect of riming on snowfall. The rime mass fraction is derived from these measurements by following the approach that is used in a single ice-phase category microphysical scheme proposed for the use in numerical weather prediction models. One of the characteristics of the proposed scheme is that the prefactor of a power law relation that links mass and size of ice particles is determined by the rime mass fraction, while the exponent does not change. To derive the rime mass fraction, a mass-dimensional relation representative of unrimed snow is also determined. To check the validity of the proposed retrieval method, the derived rime mass fraction is converted to the effective liquid water path that is compared to microwave radiometer observations. Since dual-polarization radar observations are often used to detect riming, the impact of riming on dual-polarization radar variables is studied for differential reflectivity measurements. It is shown that the relation between rime mass fraction and differential reflectivity is ambiguous, other factors such as change in median volume diameter need also be considered. Given the current interest on sensitivity of precipitation to aerosol pollution, which could inhibit riming, the importance of riming for surface snow accumulation is investigated. It is found that riming is responsible for 5% to 40% of snowfall mass. The study is based on data collected at the University of Helsinki field station in Hyytiälä during U.S. Department of Energy Biogenic Aerosols Effects on Clouds and Climate (BAECC) field campaign and the winter 2014/2015. In total 22 winter storms were analyzed, and detailed analysis of two events is presented to illustrate the study.

  5. 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

  6. Let it snow: how snowfall and injury mechanism affect ski and snowboard injuries in Vail, Colorado, 2011-2012.

    PubMed

    Moore, S Jason; Knerl, Dana

    2013-08-01

    Current research examining the impact of mechanism of injury and daily snowfall amounts on injury severity among skiers and snowboarders is limited. The purpose of this study was to define correlations between injury mechanism and daily snowfall on injury patterns and severity among skiers and snowboarders. This observational study analyzed daily snowfall measurements coupled with trauma admissions during the 2011 and 2012 ski seasons from a Level III trauma center servicing a large North American ski resort. Post hoc adjusted analyses and multivariate modeling was used to determine independent predictors of increased injury severity. Six hundred forty-four trauma admissions were analyzed, with primary research considerations detailing the variances in injury severity resulting from collisions with other skiers or snowboarders and daily total snowfall. Findings demonstrated that collisions were independently associated with increased (1) injury severity (Injury Severity Score [ISS ≥ 16]) (odds ratio [OR], 3.9; 95% confidence interval [CI], 2.0-7.6; p < 0.001), (2) thoracic injury severity (Abbreviated Injury Scale [AIS] score ≥ 3) (OR, 7.5; 95% CI, 3.7-15.0; p < 0.001), and (3) renal injuries (OR, 3.2; 95% CI, 1.2-8.1; p = 0.017) as well as and axial skeleton fractures (OR, 4.5; 95% CI, 2.6-7.7; p < 0.001). In addition, mean ISS was significantly higher in the setting of a collision when compared with a fall (8.6 vs. 5.8; p < 0.001). Findings regarding total snowfall demonstrate a negative correlation between snowfall and injury severity (r = -0.08, p = 0.05); the majority (65.5%) of injuries were sustained when there was 1 inch or less of recent snowfall, and a snowfall total of 2 inches or less was independently associated with increased injury severity (ISS ≥ 16) (OR, 3.1; 95% CI, 1.1-9.1; p = 0.036). Collisions between snowsport enthusiasts and total trace snowfall predict an increase in injury severity among alpine skiers and snowboarders. Findings from

  7. 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).

  8. Climatological assessment of spatiotemporal trends in observational monthly snowfall totals and extremes over the Canadian Great Lakes Basin

    NASA Astrophysics Data System (ADS)

    Baijnath, Janine; Duguay, Claude; Sushama, Laxmi; Huziy, Oleksandr

    2017-04-01

    decrease in ice cover fraction, and an increase in VTGlst-850, which enhances evaporation into the lower PBL. It is suggested that inefficient moisture recycling and increase moisture storage in warmer air masses inhibits the development of HLES. The 99th percentile of snowfall events within the GLB suggests an extreme snowfall value equal to or exceeding 15 cm per day. Spatiotemporal snowfall patterns indicate that mostly lake effect processes and not extratropical cyclones drive the high intensity, frequency, and duration of these extreme events over the GLB. Furthermore, the Canadian snowbelt region of Lake Huron and Lake Superior exhibit different spatiotemporal trends in snowfall extremes but, even within a particular snowbelt region, trends in extreme snowfall are not spatially coherent. It is suggested that geographic location of the lakes, topography, lake bathymetry, and lake orientation can influence local and large scale surface-atmosphere variables.

  9. 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

  10. Intense sea-effect snowfall case on the western coast of Finland

    NASA Astrophysics Data System (ADS)

    Olsson, Taru; Perttula, Tuuli; Jylhä, Kirsti; Luomaranta, Anna

    2017-07-01

    A new national daily snowfall record was measured in Finland on 8 January 2016 when it snowed 73 cm (31 mm as liquid water) in less than a day in Merikarvia on the western coast of Finland. The area of the most intense snowfall was very small, which is common in convective precipitation. In this work we used hourly weather radar images to identify the sea-effect snowfall case and to qualitatively estimate the performance of HARMONIE, a non-hydrostatic convection-permitting weather prediction model, in simulating the spatial and temporal evolution of the snowbands. The model simulation, including data assimilation, was run at 2.5 km horizontal resolution and 65 levels in vertical. HARMONIE was found to capture the overall sea-effect snowfall situation quite well, as both the timing and the location of the most intense snowstorm were properly simulated. Based on our preliminary analysis, the snowband case was triggered by atmospheric instability above the mostly ice-free sea and a low-level convergence zone almost perpendicular to the coastline. The simulated convective available potential energy (CAPE) reached a value of 87 J kg-1 near the site of the observed snowfall record.

  11. Heavy snowfall damage Virginia pine

    Treesearch

    Richard H. Fenton

    1959-01-01

    In the Coastal Plain from Virginia to Pennsylvania, snowstorms heavy enough to damage trees are unusual. Weather Bureau records for the general area show that heavy snowfall - 8 to 25 inches in a single storm - occurs at an average frequency of about once in 7 years.

  12. 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.

  13. A 1DVAR-based snowfall rate retrieval algorithm for passive microwave radiometers

    NASA Astrophysics Data System (ADS)

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

    2017-06-01

    Snowfall rate retrieval from spaceborne passive microwave (PMW) radiometers has gained momentum in recent years. PMW can be so utilized because of its ability to sense in-cloud precipitation. A physically based, overland snowfall rate (SFR) algorithm has been developed using measurements from the Advanced Microwave Sounding Unit-A/Microwave Humidity Sounder sensor pair and the Advanced Technology Microwave Sounder. Currently, these instruments are aboard five polar-orbiting satellites, namely, NOAA-18, NOAA-19, Metop-A, Metop-B, and Suomi-NPP. The SFR algorithm relies on a separate snowfall detection algorithm that is composed of a satellite-based statistical model and a set of numerical weather prediction model-based filters. There are four components in the SFR algorithm itself: cloud properties retrieval, computation of ice particle terminal velocity, ice water content adjustment, and the determination of snowfall rate. The retrieval of cloud properties is the foundation of the algorithm and is accomplished using a one-dimensional variational (1DVAR) model. An existing model is adopted to derive ice particle terminal velocity. Since no measurement of cloud ice distribution is available when SFR is retrieved in near real time, such distribution is implicitly assumed by deriving an empirical function that adjusts retrieved SFR toward radar snowfall estimates. Finally, SFR is determined numerically from a complex integral. The algorithm has been validated against both radar and ground observations of snowfall events from the contiguous United States with satisfactory results. Currently, the SFR product is operationally generated at the National Oceanic and Atmospheric Administration and can be obtained from that organization.

  14. Enhance the accuracy of radar snowfall estimation with Multi new Z-S relationships in MRMS system

    NASA Astrophysics Data System (ADS)

    Qi, Y.

    2017-12-01

    Snow may have negative affects on roadways and human lives, but the result of the melted snow/ice is good for farm, humans, and animals. For example, in the Southwest and West mountainous area of United States, water shortage is a very big concern. However, snowfall in the winter can provide humans, animals and crops an almost unlimited water supply. So, using radar to accurately estimate the snowfall is very important for human life and economic development in the water lacking area. The current study plans to analyze the characteristics of the horizontal and vertical variations of dry/wet snow using dual polarimetric radar observations, relative humidity and in situ snow water equivalent observations from the National Weather Service All Weather Prediction Accumulation Gauges (AWPAG) across the CONUS, and establish the relationships between the reflectivity (Z) and ground snow water equivalent (S). The new Z-S relationships will be evaluated with independent CoCoRaHS (Community Collaborative Rain, Hail & Snow Network) gauge observations and eventually implemented in the Multi-Radar Multi-Sensor system for improved quantitative precipitation estimation for snow. This study will analyze the characteristics of the horizontal and vertical variations of dry/wet snow using dual polarimetric radar observations, relative humidity and in situ snow water equivalent observations from the National Weather Service All Weather Prediction Accumulation Gauges (AWPAG) across the CONUS, and establish the relationships between the reflectivity (Z) and ground snow water equivalent (S). The new Z-S relationships will be used to reduce the error of snowfall estimation in Multi Radar and Multi Sensors (MRMS) system, and tested in MRMS system and evaluated with the COCORaHS observations. Finally, it will be ingested in MRMS sytem, and running in NWS/NCAR operationally

  15. A variational technique to estimate snowfall rate from coincident radar, snowflake, and fall-speed observations

    NASA Astrophysics Data System (ADS)

    Cooper, Steven J.; Wood, Norman B.; L'Ecuyer, Tristan S.

    2017-07-01

    Estimates of snowfall rate as derived from radar reflectivities alone are non-unique. Different combinations of snowflake microphysical properties and particle fall speeds can conspire to produce nearly identical snowfall rates for given radar reflectivity signatures. Such ambiguities can result in retrieval uncertainties on the order of 100-200 % for individual events. Here, we use observations of particle size distribution (PSD), fall speed, and snowflake habit from the Multi-Angle Snowflake Camera (MASC) to constrain estimates of snowfall derived from Ka-band ARM zenith radar (KAZR) measurements at the Atmospheric Radiation Measurement (ARM) North Slope Alaska (NSA) Climate Research Facility site at Barrow. MASC measurements of microphysical properties with uncertainties are introduced into a modified form of the optimal-estimation CloudSat snowfall algorithm (2C-SNOW-PROFILE) via the a priori guess and variance terms. Use of the MASC fall speed, MASC PSD, and CloudSat snow particle model as base assumptions resulted in retrieved total accumulations with a -18 % difference relative to nearby National Weather Service (NWS) observations over five snow events. The average error was 36 % for the individual events. Use of different but reasonable combinations of retrieval assumptions resulted in estimated snowfall accumulations with differences ranging from -64 to +122 % for the same storm events. Retrieved snowfall rates were particularly sensitive to assumed fall speed and habit, suggesting that in situ measurements can help to constrain key snowfall retrieval uncertainties. More accurate knowledge of these properties dependent upon location and meteorological conditions should help refine and improve ground- and space-based radar estimates of snowfall.

  16. A variational technique to estimate snowfall rate from coincident radar, snowflake, and fall-speed observations

    DOE PAGES

    Cooper, Steven J.; Wood, Norman B.; L'Ecuyer, Tristan S.

    2017-07-20

    Estimates of snowfall rate as derived from radar reflectivities alone are non-unique. Different combinations of snowflake microphysical properties and particle fall speeds can conspire to produce nearly identical snowfall rates for given radar reflectivity signatures. Such ambiguities can result in retrieval uncertainties on the order of 100–200% for individual events. Here, we use observations of particle size distribution (PSD), fall speed, and snowflake habit from the Multi-Angle Snowflake Camera (MASC) to constrain estimates of snowfall derived from Ka-band ARM zenith radar (KAZR) measurements at the Atmospheric Radiation Measurement (ARM) North Slope Alaska (NSA) Climate Research Facility site at Barrow. MASCmore » measurements of microphysical properties with uncertainties are introduced into a modified form of the optimal-estimation CloudSat snowfall algorithm (2C-SNOW-PROFILE) via the a priori guess and variance terms. Use of the MASC fall speed, MASC PSD, and CloudSat snow particle model as base assumptions resulted in retrieved total accumulations with a -18% difference relative to nearby National Weather Service (NWS) observations over five snow events. The average error was 36% for the individual events. The use of different but reasonable combinations of retrieval assumptions resulted in estimated snowfall accumulations with differences ranging from -64 to +122% for the same storm events. Retrieved snowfall rates were particularly sensitive to assumed fall speed and habit, suggesting that in situ measurements can help to constrain key snowfall retrieval uncertainties. Furthermore, accurate knowledge of these properties dependent upon location and meteorological conditions should help refine and improve ground- and space-based radar estimates of snowfall.« less

  17. A variational technique to estimate snowfall rate from coincident radar, snowflake, and fall-speed observations

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

    Cooper, Steven J.; Wood, Norman B.; L'Ecuyer, Tristan S.

    Estimates of snowfall rate as derived from radar reflectivities alone are non-unique. Different combinations of snowflake microphysical properties and particle fall speeds can conspire to produce nearly identical snowfall rates for given radar reflectivity signatures. Such ambiguities can result in retrieval uncertainties on the order of 100–200% for individual events. Here, we use observations of particle size distribution (PSD), fall speed, and snowflake habit from the Multi-Angle Snowflake Camera (MASC) to constrain estimates of snowfall derived from Ka-band ARM zenith radar (KAZR) measurements at the Atmospheric Radiation Measurement (ARM) North Slope Alaska (NSA) Climate Research Facility site at Barrow. MASCmore » measurements of microphysical properties with uncertainties are introduced into a modified form of the optimal-estimation CloudSat snowfall algorithm (2C-SNOW-PROFILE) via the a priori guess and variance terms. Use of the MASC fall speed, MASC PSD, and CloudSat snow particle model as base assumptions resulted in retrieved total accumulations with a -18% difference relative to nearby National Weather Service (NWS) observations over five snow events. The average error was 36% for the individual events. The use of different but reasonable combinations of retrieval assumptions resulted in estimated snowfall accumulations with differences ranging from -64 to +122% for the same storm events. Retrieved snowfall rates were particularly sensitive to assumed fall speed and habit, suggesting that in situ measurements can help to constrain key snowfall retrieval uncertainties. Furthermore, accurate knowledge of these properties dependent upon location and meteorological conditions should help refine and improve ground- and space-based radar estimates of snowfall.« less

  18. Arctic Sea Ice, Eurasia Snow, and Extreme Winter Haze in China

    NASA Astrophysics Data System (ADS)

    Zou, Y.; Wang, Y.; Xie, Z.; Zhang, Y.; Koo, J. H.

    2017-12-01

    Eastern China is experiencing more severe haze pollution in winter during recent years. Though the environmental deterioration in this region is usually attributed to the high intensity of anthropogenic emissions and large contributions from secondary aerosol formation, the impact of climate variability is also indispensable given its significant influence on regional weather systems and pollution ventilation. Here we analyzed the air quality related winter meteorological conditions over Eastern China in the last four decades and showed a worsening trend in poor regional air pollutant ventilation. Such variations increased the probability of extreme air pollution events, which is in good agreement with aerosol observations of recent years. We further identified the key circulation pattern that is conducive to the weakening ventilation and investigated the relationship between synoptic circulation changes and multiple climate forcing variables. Both statistical analysis and numerical sensitivity experiments suggested that the poor ventilation condition is linked to boreal cryosphere changes including Arctic sea ice in preceding autumn and Eurasia snowfall in earlier winter. We conducted comprehensive dynamic diagnosis and proposed a physical mechanism to explain the observed and simulated circulation changes. At last, we examined future projections of winter extreme stagnation events based on the CMIP5 projection data.

  19. 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

  20. Ixodes ricinus parasitism of birds increases at higher winter temperatures.

    PubMed

    Furness, Robert W; Furness, Euan N

    2018-06-01

    Increasing winter temperatures are expected to cause seasonal activity of Ixodes ricinus ticks to extend further into the winter. We caught birds during winter months (November to February) at a site in the west of Scotland over a period of 24 years (1993-1994 to 2016-2017) to quantify numbers of attached I. ricinus and to relate these to monthly mean temperature. No adult ticks were found on any of the 21,731 bird captures, but 946 larvae and nymphs were found, with ticks present in all winter months, on 16 different species of bird hosts. All ticks identified to species were I. ricinus. I. ricinus are now active throughout the year in this area providing temperature permits. No I. ricinus were present in seven out of eight months when the mean temperature was below 3.5º C. Numbers of I. ricinus attached to birds increased rapidly with mean monthly temperatures above 7º C. Winter temperatures in Scotland have been above the long-term average in most years in the last two decades, and this is likely to increase risk of tick-borne disease. © 2018 The Society for Vector Ecology.

  1. 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. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Estimating the snowfall limit in alpine and pre-alpine valleys: A local evaluation of operational approaches

    NASA Astrophysics Data System (ADS)

    Fehlmann, Michael; Gascón, Estíbaliz; Rohrer, Mario; Schwarb, Manfred; Stoffel, Markus

    2018-05-01

    The snowfall limit has important implications for different hazardous processes associated with prolonged or heavy precipitation such as flash floods, rain-on-snow events and freezing precipitation. To increase preparedness and to reduce risk in such situations, early warning systems are frequently used to monitor and predict precipitation events at different temporal and spatial scales. However, in alpine and pre-alpine valleys, the estimation of the snowfall limit remains rather challenging. In this study, we characterize uncertainties related to snowfall limit for different lead times based on local measurements of a vertically pointing micro rain radar (MRR) and a disdrometer in the Zulg valley, Switzerland. Regarding the monitoring, we show that the interpolation of surface temperatures tends to overestimate the altitude of the snowfall limit and can thus lead to highly uncertain estimates of liquid precipitation in the catchment. This bias is much smaller in the Integrated Nowcasting through Comprehensive Analysis (INCA) system, which integrates surface station and remotely sensed data as well as outputs of a numerical weather prediction model. To reduce systematic error, we perform a bias correction based on local MRR measurements and thereby demonstrate the added value of such measurements for the estimation of liquid precipitation in the catchment. Regarding the nowcasting, we show that the INCA system provides good estimates up to 6 h ahead and is thus considered promising for operational hydrological applications. Finally, we explore the medium-range forecasting of precipitation type, especially with respect to rain-on-snow events. We show for a selected case study that the probability for a certain precipitation type in an ensemble-based forecast is more persistent than the respective type in the high-resolution forecast (HRES) of the European Centre for Medium Range Weather Forecasts Integrated Forecasting System (ECMWF IFS). In this case study, the

  3. Increasing frequency and duration of Arctic winter warming events

    NASA Astrophysics Data System (ADS)

    Graham, R. M.; Cohen, L.; Petty, A.; Boisvert, L.; Rinke, A.; Hudson, S. R.; Nicolaus, M.; Granskog, M. A.

    2017-12-01

    Record low Arctic sea ice extents were observed during the last three winter seasons (March). During each of these winters, near-surface air temperatures close to 0°C were observed, in situ, over sea ice in the central Arctic. Recent media reports and scientific studies suggest that such winter warming events were unprecedented for the Arctic. Here we use in situ winter (December-March) temperature observations, such as those from Soviet North Pole drifting stations and ocean buoys, to determine how common Arctic winter warming events are. The earliest record we find of a winter warming event was in March 1896, where a temperature of -3.7˚C was observed at 84˚N during the Fram expedition. Observations of winter warming events exist over most of the Arctic Basin. Despite a limited observational network, temperatures exceeding -5°C were measured in situ during more than 30% of winters from 1954 to 2010, by either North Pole drifting stations or ocean buoys. Correlation coefficients between the atmospheric reanalysis, ERA-Interim, and these in-situ temperature records are shown to be on the order of 0.90. This suggests that ERA-Interim is a suitable tool for studying Arctic winter warming events. Using the ERA-Interim record (1979-2016), we show that the North Pole (NP) region typically experiences 10 warming events (T2m > -10°C) per winter, compared with only five in the Pacific Central Arctic (PCA). We find a positive trend in the overall duration of winter warming events for both the NP region (4.25 days/decade) and PCA (1.16 days/decade), due to an increased number of events of longer duration.

  4. 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

  5. Anatomy of a late spring snowfall on sea ice

    NASA Astrophysics Data System (ADS)

    Perovich, Donald; Polashenski, Christopher; Arntsen, Alexandra; Stwertka, Carolyn

    2017-03-01

    Spring melt initiation is a critical process for Arctic sea ice. Melting conditions decrease surface albedo at a time of high insolation, triggering powerful albedo feedback. Weather events during melt initiation, such as new snowfalls, can stop or reverse the albedo decline, however. Here we present field observations of such a snow event and demonstrate its enduring impact through summer. Snow fell 3-6 June 2014 in the Chukchi Sea, halting melt onset. The snow not only raised albedo but also provided a significant negative latent heat flux, averaging -51 W m-2 from 3 to 6 June. The snowfall delayed sustained melt by 11 days, creating cascading impacts on surface energy balance that totaled some 135 MJ/m2 by mid-August. The findings highlight the sensitivity of sea ice conditions on seasonal time scales to melt initiation processes.

  6. Use of coincident radar and radiometer observations from GPM, ATMS, and CloudSat for global spaceborne snowfall observation assessment

    NASA Astrophysics Data System (ADS)

    Panegrossi, Giulia; Casella, Daniele; Sanò, Paolo; Cinzia Marra, Anna; Dietrich, Stefano; Johnson, Benjamin T.; Kulie, Mark S.

    2017-04-01

    Snowfall is the main component of the global precipitation amount at mid and high latitudes, and improvement of global spaceborne snowfall quantitative estimation is one of the main goals of the Global Precipitation Measurement (GPM) mission. Advancements in snowfall detection and retrieval accuracy at mid-high latitudes are expected from both instruments on board the GPM Core Observatory (GPM-CO): the GMI, the most advanced conical precipitation radiometer with respect to both channel assortment and spatial resolution; and the Dual-frequency Precipitation Radar (DPR) (Ka and Ku band). Moreover, snowfall monitoring is now possible by exploiting the high frequency channels (i.e. >100 GHz) available from most of the microwave radiometers in the GPM constellation providing good temporal coverage at mid-high latitudes (hourly or less). Among these, the Advanced Technology Microwave Sounder (ATMS) onboard Suomi-NPP is the most advanced polar-orbiting cross track radiometer with 5 channels in the 183 GHz oxygen absorption band. Finally, CloudSat carries the W-band Cloud Profiling Radar (CPR) that has collected data since its launch in 2006. While CPR was primarily designed as a cloud remote sensing mission, its high-latitude coverage (up to 82° latitude) and high radar sensitivity ( -28 dBZ) make it very suitable for snowfall-related research. In this work a number of global datasets made of coincident observations of snowfall producing clouds from the spaceborne radars DPR and CPR and from the most advanced radiometers available (GMI and ATMS) have been created and analyzed. We will show the results of a study where CPR is used to: 1) assess snowfall detection and estimate capabilities of DPR; 2) analyze snowfall signatures in the high frequency channels of the passive microwave radiometers in relation to fundamental environmental conditions. We have estimated that DPR misses a very large fraction of snowfall precipitation (more than 90% of the events and around 70% of

  7. Arctic sea ice, Eurasia snow, and extreme winter haze in China.

    PubMed

    Zou, Yufei; Wang, Yuhang; Zhang, Yuzhong; Koo, Ja-Ho

    2017-03-01

    The East China Plains (ECP) region experienced the worst haze pollution on record for January in 2013. We show that the unprecedented haze event is due to the extremely poor ventilation conditions, which had not been seen in the preceding three decades. Statistical analysis suggests that the extremely poor ventilation conditions are linked to Arctic sea ice loss in the preceding autumn and extensive boreal snowfall in the earlier winter. We identify the regional circulation mode that leads to extremely poor ventilation over the ECP region. Climate model simulations indicate that boreal cryospheric forcing enhances the regional circulation mode of poor ventilation in the ECP region and provides conducive conditions for extreme haze such as that of 2013. Consequently, extreme haze events in winter will likely occur at a higher frequency in China as a result of the changing boreal cryosphere, posing difficult challenges for winter haze mitigation but providing a strong incentive for greenhouse gas emission reduction.

  8. Arctic sea ice, Eurasia snow, and extreme winter haze in China

    PubMed Central

    Zou, Yufei; Wang, Yuhang; Zhang, Yuzhong; Koo, Ja-Ho

    2017-01-01

    The East China Plains (ECP) region experienced the worst haze pollution on record for January in 2013. We show that the unprecedented haze event is due to the extremely poor ventilation conditions, which had not been seen in the preceding three decades. Statistical analysis suggests that the extremely poor ventilation conditions are linked to Arctic sea ice loss in the preceding autumn and extensive boreal snowfall in the earlier winter. We identify the regional circulation mode that leads to extremely poor ventilation over the ECP region. Climate model simulations indicate that boreal cryospheric forcing enhances the regional circulation mode of poor ventilation in the ECP region and provides conducive conditions for extreme haze such as that of 2013. Consequently, extreme haze events in winter will likely occur at a higher frequency in China as a result of the changing boreal cryosphere, posing difficult challenges for winter haze mitigation but providing a strong incentive for greenhouse gas emission reduction. PMID:28345056

  9. Increase in winter haze over eastern China in recent decades: Roles of variations in meteorological parameters and anthropogenic emissions: INCREASE IN WINTER HAZE IN EASTERN CHINA

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

    Yang, Yang; Liao, Hong; Lou, Sijia

    The increase in winter haze over eastern China in recent decades due to variations in meteorological parameters and anthropogenic emissions was quantified using observed atmospheric visibility from the National Climatic Data Center Global Summary of Day database for 1980–2014 and simulated PM2.5 concentrations for 1985–2005 from the Goddard Earth Observing System (GEOS) chemical transport model (GEOS-Chem). Observed winter haze days averaged over eastern China (105–122.5°E, 20–45°N) increased from 21 d in 1980 to 42 d in 2014, and from 22 to 30 d between 1985 and 2005. The GEOS-Chem model captured the increasing trend of winter PM2.5 concentrations for 1985–2005,more » with concentrations averaged over eastern China increasing from 16.1 μg m -3 in 1985 to 38.4 μg m -3 in 2005. Considering variations in both anthropogenic emissions and meteorological parameters, the model simulated an increase in winter surface-layer PM2.5 concentrations of 10.5 (±6.2) μg m -3 decade -1 over eastern China. The increasing trend was only 1.8 (±1.5) μg m -3 decade -1 when variations in meteorological parameters alone were considered. Among the meteorological parameters, the weakening of winds by -0.09 m s -1 decade -1 over 1985–2005 was found to be the dominant factor leading to the decadal increase in winter aerosol concentrations and haze days over eastern China during recent decades.« less

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Physical activity levels of community-dwelling older adults are influenced by winter weather variables.

    PubMed

    Jones, G R; Brandon, C; Gill, D P

    2017-07-01

    Winter weather conditions may negatively influence participation of older adults in daily physical activity (PA). Assess the influence of winter meteorological variables, day-time peak ambient temperature, windchill, humidity, and snow accumulation on the ground to accelerometer measured PA values in older adults. 50 community-dwelling older adults (77.4±4.7yrs; range 71-89; 12 females) living in Southwestern Ontario (Latitude 42.9°N Longitude 81.2° W) Canada, wore a waist-borne accelerometer during active waking hours (12h) for 7 consecutive days between February and April 2007. Hourly temperature, windchill, humidity, and snowfall accumulation were obtained from meteorological records and time locked to hourly accelerometer PA values. Regression analysis revealed significant relationships between time of day, ambient daytime high temperature and a humidity for participation in PA. Windchill temperature added no additional influence over PA acclamation already influenced by ambient day-time temperature and the observed variability in PA patterns relative to snow accumulation over the study period was too great to warrant its inclusion in the model. Most PA was completed in the morning hours and increased as the winter month's transitioned to spring (February through April). An equation was developed to adjust for winter weather conditions using temperature, humidity and time of day. Accurate PA assessment during the winter months must account for the ambient daytime high temperatures, humidity, and time of day. These older adults were more physically active during the morning hours and became more active as the winter season transitioned to spring. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Ground based remote sensing retrievals and observations of snowfall in the Telemark region of Norway

    NASA Astrophysics Data System (ADS)

    Pettersen, C.; L'Ecuyer, T. S.; Wood, N.; Cooper, S.; Wolff, M. A.; Petersen, W. A.; Bliven, L. F.; Tushaus, S. A.

    2017-12-01

    Snowfall can be broadly categorized into deep and shallow events, based on the vertical extent of the frozen precipitation in the column. The two categories are driven by different thermodynamic and physical mechanisms in the atmosphere and surface. Though satellites can observe and recognize these patterns in snowfall, these measurements are limited - particularly in cases of shallow and light precipitation and over complex terrain. By enhancing satellite measurements with ground-based instrumentation, whether with limited-term field campaigns or long-term strategic sites, we can further our understanding and assumptions about different snowfall modes. We present data collected in a recently deployed ground suite of instruments based in Norway. The Meteorological Institute of Norway has a snow measurement suite in Haukeliseter located in the orographically complex Telemark region. This suite consists of several snow accumulation instruments as well as meteorological data (temperature, dew point, wind speeds and directions). A joint project between University of Wisconsin and University of Utah augmented this suite with a 24 GHz radar MicroRain Radar (MRR), a NASA Particle Imaging Package (PIP), and a Multi-Angle Snowflake Camera (MASC). Preliminary data from this campaign are presented along with coincident overpasses from the GPM satellite. We compare the ground-based and spaceborne remotely sensed estimates of snowfall with snow gauge observations from the Haukeliseter site. Finally, we discuss how particle size distribution and fall velocity observations from the PIP and MASC can be used to improve remotely-sensed snowfall retrievals as a function of environmental conditions at Haukeliseter.

  16. Spatial Analysis of the Effects of the Anomalous Winter of 2014/15 on 157 Ski Resorts Located in Western North America

    NASA Astrophysics Data System (ADS)

    Bahbahani, K. M.; Pidwirny, M. J.

    2017-12-01

    The winter of 2014/2015 was one of the warmest in recent history for many locations in western North America. The cause of this climate irregularity was the development of extremely warm ocean surface waters (The Blob) over much of the eastern North Pacific Ocean. During this winter season, many ski resorts in western Canada and the United States either did not open or were forced to close their ski season early. Here, we examine climate data from 157 ski resorts to develop a picture of where the effected locations were in western North America. Using the climate database software ClimateBC and ClimateNA, high quality downscaled historical data was generated for the winter season (December, January, and February) for the variables mean temperature, snowfall, and rainfall. Values for winter of 2014/15 were statistically compared to the 30-year normal period from 1981-2010. Z-scores were calculated for 2014/15 relative to the selected 30-year normal period. These Z-score values were then mapped using ArcGIS. From the mean winter temperature map, it is apparent that abnormally warm temperatures influenced many ski resorts in California, Nevada, western Oregon, Washington, Arizona, Utah, southern Idaho, and parts of southern British Columbia. The winter snowfall map shows anomalous below normal conditions only at two resorts in south-central British Columbia and a single above normal situation at one site in central Colorado. The winter rainfall map displays that many ski resorts in New Mexico, Arizona, southern Utah, Colorado, Wyoming, Montana, Idaho, western Washington, and southwestern British Columbia experienced exceptional above normal winter season rainfalls. It is highly likely that the next Blob will be forecasted many months in advance of its occurrence. The results of this study have identified which ski resorts could be climatically influenced by such an event. This information may help reduce potential financial losses to ski resorts and their associated

  17. Influence of sub-kilometer precipitation datasets on simulated snowpack and glacier winter balance in alpine terrain.

    NASA Astrophysics Data System (ADS)

    Vionnet, Vincent; Six, Delphine; Auger, Ludovic; Lafaysse, Matthieu; Quéno, Louis; Réveillet, Marion; Dombrowski-Etchevers, Ingrid; Thibert, Emmanuel; Dumont, Marie

    2017-04-01

    Capturing spatial and temporal variabilities of meteorological conditions at fine scale is necessary for modelling snowpack and glacier winter mass balance in alpine terrain. In particular, precipitation amount and phase are strongly influenced by the complex topography. In this study, we assess the impact of three sub-kilometer precipitation datasets (rainfall and snowfall) on distributed simulations of snowpack and glacier winter mass balance with the detailed snowpack model Crocus for winter 2011-2012. The different precipitation datasets at 500-m grid spacing over part of the French Alps (200*200 km2 area) are coming either from (i) the SAFRAN precipitation analysis specially developed for alpine terrain, or from (ii) operational outputs of the atmospheric model AROME at 2.5-km grid spacing downscaled to 500 m with fixed lapse rate or from (iii) a version of the atmospheric model AROME at 500-m grid spacing. Others atmospherics forcings (air temperature and humidity, incoming longwave and shortwave radiation, wind speed) are taken from the AROME simulations at 500-m grid spacing. These atmospheric forcings are firstly compared against a network of automatic weather stations. Results are analysed with respect to station location (valley, mid- and high-altitude). The spatial pattern of seasonal snowfall and its dependency with elevation is then analysed for the different precipitation datasets. Large differences between SAFRAN and the two versions of AROME are found at high-altitude. Finally, results of Crocus snowpack simulations are evaluated against (i) punctual in-situ measurements of snow depth and snow water equivalent, and (ii) maps of snow covered areas retrieved from optical satellite data (MODIS). Measurements of winter accumulation of six glaciers of the French Alps are also used and provide very valuable information on precipitation at high-altitude where the conventional observation network is scarce. This study illustrates the potential and

  18. Observation of snowfall with a low-power FM-CW K-band radar (Micro Rain Radar)

    NASA Astrophysics Data System (ADS)

    Kneifel, Stefan; Maahn, Maximilian; Peters, Gerhard; Simmer, Clemens

    2011-06-01

    Quantifying snowfall intensity especially under arctic conditions is a challenge because wind and snow drift deteriorate estimates obtained from both ground-based gauges and disdrometers. Ground-based remote sensing with active instruments might be a solution because they can measure well above drifting snow and do not suffer from flow distortions by the instrument. Clear disadvantages are, however, the dependency of e.g. radar returns on snow habit which might lead to similar large uncertainties. Moreover, high sensitivity radars are still far too costly to operate in a network and under harsh conditions. In this paper we compare returns from a low-cost, low-power vertically pointing FM-CW radar (Micro Rain Radar, MRR) operating at 24.1 GHz with returns from a 35.5 GHz cloud radar (MIRA36) for dry snowfall during a 6-month observation period at an Alpine station (Environmental Research Station Schneefernerhaus, UFS) at 2,650 m height above sea level. The goal was to quantify the potential and limitations of the MRR in relation to what is achievable by a cloud radar. The operational MRR procedures to derive standard radar variables like effective reflectivity factor ( Z e) or the mean Doppler velocity ( W) had to be modified for snowfall since the MRR was originally designed for rain observations. Since the radar returns from snowfall are weaker than from comparable rainfall, the behavior of the MRR close to its detection threshold has been analyzed and a method is proposed to quantify the noise level of the MRR based on clear sky observations. By converting the resulting MRR- Z e into 35.5 GHz equivalent Z e values, a remaining difference below 1 dBz with slightly higher values close to the noise threshold could be obtained. Due to the much higher sensitivity of MIRA36, the transition of the MRR from the true signal to noise can be observed, which agrees well with the independent clear sky noise estimate. The mean Doppler velocity differences between both radars

  19. Biogeochemical Impact of Snow Cover and Cyclonic Intrusions on the Winter Weddell Sea Ice Pack

    NASA Astrophysics Data System (ADS)

    Tison, J.-L.; Schwegmann, S.; Dieckmann, G.; Rintala, J.-M.; Meyer, H.; Moreau, S.; Vancoppenolle, M.; Nomura, D.; Engberg, S.; Blomster, L. J.; Hendrickx, S.; Uhlig, C.; Luhtanen, A.-M.; de Jong, J.; Janssens, J.; Carnat, G.; Zhou, J.; Delille, B.

    2017-12-01

    Sea ice is a dynamic biogeochemical reactor and a double interface actively interacting with both the atmosphere and the ocean. However, proper understanding of its annual impact on exchanges, and therefore potentially on the climate, notably suffer from the paucity of autumnal and winter data sets. Here we present the results of physical and biogeochemical investigations on winter Antarctic pack ice in the Weddell Sea (R. V. Polarstern AWECS cruise, June-August 2013) which are compared with those from two similar studies conducted in the area in 1986 and 1992. The winter 2013 was characterized by a warm sea ice cover due to the combined effects of deep snow and frequent warm cyclones events penetrating southward from the open Southern Ocean. These conditions were favorable to high ice permeability and cyclic events of brine movements within the sea ice cover (brine tubes), favoring relatively high chlorophyll-a (Chl-a) concentrations. We discuss the timing of this algal activity showing that arguments can be presented in favor of continued activity during the winter due to the specific physical conditions. Large-scale sea ice model simulations also suggest a context of increasingly deep snow, warm ice, and large brine fractions across the three observational years, despite the fact that the model is forced with a snowfall climatology. This lends support to the claim that more severe Antarctic sea ice conditions, characterized by a longer ice season, thicker, and more concentrated ice are sufficient to increase the snow depth and, somehow counterintuitively, to warm the ice.

  20. Using snowflake surface-area-to-volume ratio to model and interpret snowfall triple-frequency radar signatures

    NASA Astrophysics Data System (ADS)

    Gergely, Mathias; Cooper, Steven J.; Garrett, Timothy J.

    2017-10-01

    The snowflake microstructure determines the microwave scattering properties of individual snowflakes and has a strong impact on snowfall radar signatures. In this study, individual snowflakes are represented by collections of randomly distributed ice spheres where the size and number of the constituent ice spheres are specified by the snowflake mass and surface-area-to-volume ratio (SAV) and the bounding volume of each ice sphere collection is given by the snowflake maximum dimension. Radar backscatter cross sections for the ice sphere collections are calculated at X-, Ku-, Ka-, and W-band frequencies and then used to model triple-frequency radar signatures for exponential snowflake size distributions (SSDs). Additionally, snowflake complexity values obtained from high-resolution multi-view snowflake images are used as an indicator of snowflake SAV to derive snowfall triple-frequency radar signatures. The modeled snowfall triple-frequency radar signatures cover a wide range of triple-frequency signatures that were previously determined from radar reflectivity measurements and illustrate characteristic differences related to snow type, quantified through snowflake SAV, and snowflake size. The results show high sensitivity to snowflake SAV and SSD maximum size but are generally less affected by uncertainties in the parameterization of snowflake mass, indicating the importance of snowflake SAV for the interpretation of snowfall triple-frequency radar signatures.

  1. First Day of Winter Obvious on NASA Satellite Image of the U.S. Plains States

    NASA Image and Video Library

    2017-12-08

    Winter arrived officially on Dec. 22 at 12:35 a.m. EST, but the U.S. Plains states received an early and cool welcome on Dec. 19 from heavy snowfall that was seen by a NASA satellite. NASA's Aqua satellite passed overhead on Dec. 21 at 20:05 UTC (3:05 p.m. EST) and the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard NASA's Aqua satellite captured a visible image of snow blanketing the ground through west and central Kansas, eastern and central Colorado, much of New Mexico, northern Texas and the panhandle of Oklahoma. According to CBS News, blizzard conditions were reported in northern New Mexico, the Texas Panhandle, Oklahoma and northwestern Kansas. The Associated Press reported snow drifts as high as 10 feet in southeast Colorado. Six people lost their lives in traffic accidents from this storm. Heavy snow is expected again today, Dec. 22 in New Mexico and Colorado. Snow is also expected to stretch across the plains into the upper Midwest today, according to the National Weather Service. Portions of many states are expecting some snow today, including the four corners states, north Texas, Kansas, southern Nebraska, western Oklahoma, northern Missouri, Iowa, northern Illinois and southern Wisconsin stretching east into northern New England. The first day of the winter season occurs when the sun is farthest south, either Dec. 21 or 22. The day is also known as the winter solstice. By the second day of winter, NASA's Aqua satellite is going to have a lot more snowfall to observe. Image Credit: NASA Goddard MODIS Rapid Response Team Caption: NASA, Rob Gutro NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  2. Influence of projected snow and sea-ice changes on future climate in heavy snowfall region

    NASA Astrophysics Data System (ADS)

    Matsumura, S.; Sato, T.

    2011-12-01

    Snow/ice albedo and cloud feedbacks are critical for climate change projection in cryosphere regions. However, future snow and sea-ice distributions are significantly different in each GCM. Thus, surface albedo in cryosphere regions is one of the causes of the uncertainty for climate change projection. Northern Japan is one of the heaviest snowfall regions in the world. In particular, Hokkaido is bounded on the north by the Okhotsk Sea, where is the southernmost ocean in the Northern Hemisphere that is covered with sea ice during winter. Wintertime climate around Hokkaido is highly sensitive to fluctuations in snow and sea-ice. The purpose of this study is to evaluate the influence of global warming on future climate around Hokkaido, using the Pseudo-Global-Warming method (PGW) by a regional climate model. The boundary conditions of the PGW run were obtained by adding the difference between the future (2090s) and past (1990s) climates simulated by coupled general circulation model (MIROC3.2 medres), which is from the CMIP3 multi-model dataset, into the 6-hourly NCEP reanalysis (R-2) and daily OISST data in the past climate (CTL) run. The PGW experiments show that snow depth significantly decreases over mountainous areas and snow cover mainly decreases over plain areas, contributing to higher surface warming due to the decreased snow albedo. Despite the snow reductions, precipitation mainly increases over the mountainous areas because of enhanced water vapor content. However, precipitation decreases over the Japan Sea and the coastal areas, indicating the weakening of a convergent cloud band, which is formed by convergence between cold northwesteries from the Eurasian continent and anticyclonic circulation over the Okhotsk Sea. These results suggest that Okhotsk sea-ice decline may change the atmospheric circulation and the resulting effect on cloud formation, resulting in changes in winter snow or precipitation. We will also examine another CMIP3 model (MRI-CGCM2

  3. Triple-frequency radar retrievals of snowfall properties from the OLYMPEX field campaign

    NASA Astrophysics Data System (ADS)

    Leinonen, J. S.; Lebsock, M. D.; Sy, O. O.; Tanelli, S.

    2017-12-01

    Retrieval of snowfall properties with radar is subject to significant errors arising from the uncertainties in the size and structure of snowflakes. Recent modeling and theoretical studies have shown that multi-frequency radars can potentially constrain the microphysical properties and thus reduce the uncertainties in the retrieved snow water content. So far, there have only been limited efforts to leverage the theoretical advances in actual snowfall retrievals. In this study, we have implemented an algorithm that retrieves the snowfall properties from triple-frequency radar data using the radar scattering properties from a combination of snowflake scattering databases, which were derived using numerical scattering methods. Snowflake number concentration, characteristic size and density are derived using a combination of optimal estimation and Kalman smoothing; the snow water content and other bulk properties are then derived from these. The retrieval framework is probabilistic and thus naturally provides error estimates for the retrieved quantities. We tested the retrieval algorithm using data from the APR3 airborne radar flown onboard the NASA DC-8 aircraft during the Olympic Mountain Experiment (OLYMPEX) in late 2015. We demonstrated consistent retrieval of snow properties and smooth transition from single- and dual-frequency retrievals to using all three frequencies simultaneously. The error analysis shows that the retrieval accuracy is improved when additional frequencies are introduced. We also compare the findings to in situ measurements of snow properties as well as measurements by polarimetric ground-based radar.

  4. 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.

  5. Large-Scale Antecedent Conditions Associated with 2014-2015 Winter Onset over North America and mid-Winter Storminess Along the North Atlantic Coast

    NASA Astrophysics Data System (ADS)

    Bosart, L. F.; Papin, P. P.; Bentley, A. M.; Benjamin, M.; Winters, A. C.

    2015-12-01

    Winter 2014-2015 was marked by the coldest November weather in 35 years east of the Rockies and record-breaking snowstorms and cold from the eastern Great Lakes to Atlantic Canada in January and February 2015. Record-breaking warmth prevailed across the Intermountain West and Rockies beneath a persistent upper-level ridge. Winter began with a series of arctic air mass surges that culminated in an epic lake-effect snowstorm occurred over western New York before Thanksgiving and was followed by a series of snow and ice storms that disrupted Thanksgiving holiday travel widely. Winter briefly abated in part of December, but returned with a vengeance between mid-January and mid-February 2015 when multiple extreme weather events that featured record-breaking monthly and seasonal snowfalls and record-breaking daily minimum temperatures were observed. This presentation will show how: (1) the recurvature and extratropical transition (ET) of Supertyphoon (STY) Nuri in the western Pacific in early November 2014, and its subsequent explosive reintensification as an extratropical cyclone (EC), disrupted the North Pacific jet stream and downstream Northern Hemisphere (NH) circulation, produced high-latitude ridging and the formation of an omega block over western North America, triggered downstream baroclinic development and the formation of a deep trough over eastern North America, and ushered in winter 2014-2015, (2) the ET/EC of STY Nuri increased subsequent week two predictability over the North Pacific and North America in association with diabatically influenced high-latitude ridge building, and (3) the amplification of the large-scale NH flow pattern beginning in January 2015 resulted in the formation of persistent high-amplitude ridges over northeastern Russia, Alaska, western North America, and the North Atlantic while deep troughs formed over the eastern North Pacific and eastern North America. This persistent amplified flow pattern supported the occurrence of frequent

  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.; 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

  7. 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.

  8. Increased body mass of ducks wintering in California's Central Valley

    USGS Publications Warehouse

    Fleskes, Joseph P.; Yee, Julie L.; Yarris, Gregory S.; Loughman, Daniel L.

    2016-01-01

    Waterfowl managers lack the information needed to fully evaluate the biological effects of their habitat conservation programs. We studied body condition of dabbling ducks shot by hunters at public hunting areas throughout the Central Valley of California during 2006–2008 compared with condition of ducks from 1979 to 1993. These time periods coincide with habitat increases due to Central Valley Joint Venture conservation programs and changing agricultural practices; we modeled to ascertain whether body condition differed among waterfowl during these periods. Three dataset comparisons indicate that dabbling duck body mass was greater in 2006–2008 than earlier years and the increase was greater in the Sacramento Valley and Suisun Marsh than in the San Joaquin Valley, differed among species (mallard [Anas platyrhynchos], northern pintail [Anas acuta], America wigeon [Anas americana], green-winged teal [Anas crecca], and northern shoveler [Anas clypeata]), and was greater in ducks harvested late in the season. Change in body mass also varied by age–sex cohort and month for all 5 species and by September–January rainfall for all except green-winged teal. The random effect of year nested in period, and sometimes interacting with other factors, improved models in many cases. Results indicate that improved habitat conditions in the Central Valley have resulted in increased winter body mass of dabbling ducks, especially those that feed primarily on seeds, and this increase was greater in regions where area of post-harvest flooding of rice and other crops, and wetland area, has increased. Conservation programs that continue to promote post-harvest flooding and other agricultural practices that benefit wintering waterfowl and continue to restore and conserve wetlands would likely help maintain body condition of wintering dabbling ducks in the Central Valley of California.

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

    USGS Publications Warehouse

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

    2014-01-01

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

  10. 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

  11. Anomalous winter-snow-amplified earthquake-induced disaster of the 2015 Langtang avalanche in Nepal

    NASA Astrophysics Data System (ADS)

    Fujita, Koji; Inoue, Hiroshi; Izumi, Takeki; Yamaguchi, Satoru; Sadakane, Ayako; Sunako, Sojiro; Nishimura, Kouichi; Immerzeel, Walter W.; Shea, Joseph M.; Kayastha, Rijan B.; Sawagaki, Takanobu; Breashears, David F.; Yagi, Hiroshi; Sakai, Akiko

    2017-05-01

    Coseismic avalanches and rockfalls, as well as their simultaneous air blast and muddy flow, which were induced by the 2015 Gorkha earthquake in Nepal, destroyed the village of Langtang. In order to reveal volume and structure of the deposit covering the village, as well as sequence of the multiple events, we conducted an intensive in situ observation in October 2015. Multitemporal digital elevation models created from photographs taken by helicopter and unmanned aerial vehicles reveal that the deposit volumes of the primary and succeeding events were 6.81 ± 1.54 × 106 and 0.84 ± 0.92 × 106 m3, respectively. Visual investigations of the deposit and witness statements of villagers suggest that the primary event was an avalanche composed mostly of snow, while the collapsed glacier ice could not be dominant source for the total mass. Succeeding events were multiple rockfalls which may have been triggered by aftershocks. From the initial deposit volume and the area of the upper catchment, we estimate an average snow depth of 1.82 ± 0.46 m in the source area. This is consistent with anomalously large snow depths (1.28-1.52 m) observed at a neighboring glacier (4800-5100 m a.s.l.), which accumulated over the course of four major snowfall events between October 2014 and the earthquake on 25 April 2015. Considering long-term observational data, probability density functions, and elevation gradients of precipitation, we conclude that this anomalous winter snow was an extreme event with a return interval of at least 100 years. The anomalous winter snowfall may have amplified the disastrous effects induced by the 2015 Gorkha earthquake in Nepal.

  12. 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

  13. Decrease in glacier coverage contributes to increased winter baseflow of Arctic rivers

    NASA Astrophysics Data System (ADS)

    Liljedahl, A. K.; Gaedeke, A.; Baraer, M.; Chesnokova, A.; Lebedeva, L.; Makarieva, O.; O'Neel, S.

    2016-12-01

    Rising minimum daily flows in northern Eurasian and North American rivers suggest a growing influence of groundwater in the Arctic hydrological cycle, while the impact of a warmer high-latitude climate system is evident in decreased glacier coverage and increasing permafrost temperatures. Multiple mechanisms have been proposed to explain the increased discharge, which is well documented but relatively poorly understood. Here we assess the long-term (up to 88 yrs) linkages between climate, glaciers and hydrology in Alaska, Canadian and Russian glacierized (from 0.3 to 60% glacier cover) and non-glacierized watersheds (31 to 186 000 km2). We are specifically interested in analyzing trends in late winter discharge from larger watersheds to refine our understanding of the regional aquifer status and annual discharge from smaller headwater basins. Field measurements of differential runoff in Interior Alaska show that glaciated headwater streams can lose significant amounts of water in summer to the underlying aquifer. The aquifer is in turn feeding the larger lowland river system throughout the year. Groundwater storage status in Arctic regions is especially prominent through winter river discharge as it is typically the only source of water to the river system for at least 6 months of the year. Our analyses aim to explore the hypothesis that the documented increase in later winter river discharge of larger watersheds can be explained at least partly, by increased glacier melt in summer as observed by long-term decreases in glacier coverage. If true, a decrease in winter freshwater exports to the Arctic Ocean could potentially follow as glaciers retreat to higher (cooler) elevations. Increased Arctic river baseflow can favor sea ice growth and fish habitats, while negatively impacting local communities in their river ice travel.

  14. How does the ice sheet surface mass balance relate to snowfall? Insights from a ground-based precipitation radar in East Antarctica

    NASA Astrophysics Data System (ADS)

    Souverijns, Niels; Gossart, Alexandra; Gorodetskaya, Irina V.; Lhermitte, Stef; Mangold, Alexander; Laffineur, Quentin; Delcloo, Andy; van Lipzig, Nicole P. M.

    2018-06-01

    Local surface mass balance (SMB) measurements are crucial for understanding changes in the total mass of the Antarctic Ice Sheet, including its contribution to sea level rise. Despite continuous attempts to decipher mechanisms controlling the local and regional SMB, a clear understanding of the separate components is still lacking, while snowfall measurements are almost absent. In this study, the different terms of the SMB are quantified at the Princess Elisabeth (PE) station in Dronning Maud Land, East Antarctica. Furthermore, the relationship between snowfall and accumulation at the surface is investigated. To achieve this, a unique collocated set of ground-based and in situ remote sensing instrumentation (Micro Rain Radar, ceilometer, automatic weather station, among others) was set up and operated for a time period of 37 months. Snowfall originates mainly from moist and warm air advected from lower latitudes associated with cyclone activity. However, snowfall events are not always associated with accumulation. During 38 % of the observed snowfall cases, the freshly fallen snow is ablated by the wind during the course of the event. Generally, snow storms of longer duration and larger spatial extent have a higher chance of resulting in accumulation on a local scale, while shorter events usually result in ablation (on average 17 and 12 h respectively). A large part of the accumulation at the station takes place when preceding snowfall events were occurring in synoptic upstream areas. This fresh snow is easily picked up and transported in shallow drifting snow layers over tens of kilometres, even when wind speeds are relatively low ( < 7 ms-1). Ablation events are mainly related to katabatic winds originating from the Antarctic plateau and the mountain ranges in the south. These dry winds are able to remove snow and lead to a decrease in the local SMB. This work highlights that the local SMB is strongly influenced by synoptic upstream conditions.

  15. Variance of laser-beam intensity fluctuations during snowfall

    NASA Astrophysics Data System (ADS)

    Zhukov, A. F.; Kabanov, M. F.; Tsvyk, R. Sh.

    1985-02-01

    The results of an experimental study of the factors affecting the variance of laser-beam intensity fluctuations during snowfall are analyzed. The investigation covered short (L = 130 m) and long (390, 650, and 1310 m) beam paths, and used narrow diverging and wide collimated beams with Omega = 0.075 and 54, respectively, produced by the same laser. The dimensions of snow particles varied from 0.1 to 3.0 cm. It is shown that a distance l exists, such that when L is much less than l a geometric shadow of a snow particle is formed, whereas for L much greater than l a complex interference pattern can be seen. In both cases, the motion of a particle leads to intensity fluctuations. Furthermore, it was found that the proportionality coefficient for Omega = 54 is near 1 and depends insignificantly on the particle size; for a diverging beam, however, it changes from 0.3 to 0.8 as the maximum particle diameter increases from 0.1 to 3 cm.

  16. Impacts of a Destructive and Well-Observed Cross-Country Winter Storm.

    NASA Astrophysics Data System (ADS)

    Martner, Brooks E.; Rauber, Robert M.; Ramamurthy, Mohan K.; Rasmussen, Roy M.; Prater, Erwin T.

    1992-02-01

    A winter storm that crossed the continental United States in mid-February 1990 produced hazardous weather across a vast area of the nation. A wide range of severe weather was reported, including heavy snowfall; freezing rain and drizzle; thunderstorms with destructive winds, lightning, large hail, and tornadoes; prolonged heavy rain with subsequent flooding; frost damage to citrus orchards; and sustained destructive winds not associated with thunderstorms. Low-end preliminary estimates of impacts included 9 deaths, 27 injuries, and $120 million of property damage. At least 35 states and southeastern Canada were adversely affected. The storm occurred during the field operations of four independent atmospheric research projects that obtained special, detailed observations of it from the Rocky Mountains to the eastern great Lakes.

  17. NASA Sees Major Winter Storm Headed for Eastern U.S.

    NASA Image and Video Library

    2017-12-08

    On Jan. 20 at 2:30 p.m. EST the VIIRS instrument aboard NASA-NOAA's Suomi NPP captured this image of the winter storm moving through the central U.S. Credits: NASA Goddard Rapid Response The low pressure area from the Eastern Pacific Ocean moved into the western U.S. and tracked across the four corners region into Texas where NASA-NOAA's Suomi NPP satellite observed the clouds associated with the storm. The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard Suomi NPP satellite captured the visible image on January 20, 2016 at 19:30 UTC (2:30 p.m. EST) when the storm was over the central U.S. In the image, snow cover is visible in the Rockies and southern Great Lakes states. VIIRS collects visible and infrared imagery and global observations of land, atmosphere, cryosphere and oceans. That low pressure system located over the south central United States on Jan. 21 is expected to track east across the Tennessee Valley and will give way to a deepening coastal low pressure area. The National Weather Service said "This latter feature takes over and becomes a dominant force in setting up heavy snow bands over the Mid-Atlantic and very gusty winds." The storm system is expected to bring an increased risk of severe weather from far southeastern Texas across southern Louisiana/Mississippi, and into the far western Florida Panhandle on Thursday, Jan. 21. That threat for severe weather will move east as the low pressure area continues heading in that direction. The National Weather Service Weather Prediction Center in College Park, Maryland said "A potentially crippling winter storm is anticipated for portions of the mid-Atlantic Friday into early Saturday. Snowfall may approach two feet for some locations, including the Baltimore and Washington, D.C. metro areas. Farther north, there is uncertainty in snowfall for the New York City-to-Boston corridor. Farther south, significant icing is likely for portions of Kentucky and North Carolina." NASA image use

  18. 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

  19. Time-Course of Cause-Specific Hospital Admissions During Snowstorms: An Analysis of Electronic Medical Records From Major Hospitals in Boston, Massachusetts

    PubMed Central

    Bobb, Jennifer F.; Ho, Kalon K. L.; Yeh, Robert W.; Harrington, Lori; Zai, Adrian; Liao, Katherine P.; Dominici, Francesca

    2017-01-01

    Abstract With global climate change, more frequent severe snowstorms are expected; however, evidence regarding their health effects is very limited. We gathered detailed medical records on hospital admissions (n = 433,037 admissions) from the 4 largest hospitals in Boston, Massachusetts, during the winters of 2010–2015. We estimated the percentage increase in hospitalizations for cardiovascular and cold-related diseases, falls, and injuries on the day of and for 6 days after a day with low (0.05–5.0 inches), moderate (5.1–10.0 inches), or high (>10.0 inches) snowfall using distributed lag regression models. We found that cardiovascular disease admissions decreased by 32% on high snowfall days (relative risk (RR) = 0.68, 95% confidence interval (CI): 0.54, 0.85) but increased by 23% 2 days after (RR = 1.23, 95% CI: 1.01, 1.49); cold-related admissions increased by 3.7% on high snowfall days (RR = 3.7, 95% CI: 1.6, 8.6) and remained high for 5 days after; and admissions for falls increased by 18% on average in the 6 days after a moderate snowfall day (RR = 1.18, 95% CI: 1.09, 1.27). We did not find a higher risk of hospitalizations for injuries. To our knowledge, this is the first study in which the time course of hospitalizations during and immediately after snowfall days has been examined. These findings can be translated into interventions that prevent hospitalizations and protect public health during harsh winter conditions. PMID:28137774

  20. 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

  1. Projected Influences of Changes in Weather Severity on Autumn-Winter Distributions of Dabbling Ducks in the Mississippi and Atlantic Flyways during the Twenty-First Century.

    PubMed

    Notaro, Michael; Schummer, Michael; Zhong, Yafang; Vavrus, Stephen; Van Den Elsen, Lena; Coluccy, John; Hoving, Christopher

    2016-01-01

    Projected changes in the relative abundance and timing of autumn-winter migration are assessed for seven dabbling duck species across the Mississippi and Atlantic Flyways for the mid- and late 21st century. Species-specific observed relationships are established between cumulative weather severity in autumn-winter and duck population rate of change. Dynamically downscaled projections of weather severity are developed using a high-resolution regional climate model, interactively coupled to a one-dimensional lake model to represent the Great Lakes and associated lake-effect snowfall. Based on the observed relationships and downscaled climate projections of rising air temperatures and reduced snow cover, delayed autumn-winter migration is expected for all species, with the least delays for the Northern Pintail and the greatest delays for the Mallard. Indeed, the Mallard, the most common and widespread duck in North America, may overwinter in the Great Lakes region by the late 21st century. This highlights the importance of protecting and restoring wetlands across the mid-latitudes of North America, including the Great Lakes Basin, because dabbling ducks are likely to spend more time there, which would impact existing wetlands through increased foraging pressure. Furthermore, inconsistency in the timing and intensity of the traditional autumn-winter migration of dabbling ducks in the Mississippi and Atlantic Flyways could have social and economic consequences to communities to the south, where hunting and birdwatching would be affected.

  2. Vascular injury is associated with increased mortality in winter sports trauma.

    PubMed

    Eun, John C; Bronsert, Michael; Hansen, Kristine; Moulton, Steven L; Jazaeri, Omid; Nehler, Mark; Greenberg, Joshua I

    2015-01-01

    Trauma is the leading cause of injury and death for individuals aged 1-44 years. Up to 8% of the US population participates in winter sports, and although vascular injuries are uncommon in these activities, little is published in this area. We sought to identify the incidence, injury patterns, and outcomes of vascular injuries resulting from winter sports trauma. Patients with winter sports trauma and the subset with vascular injuries were identified by accessing the National Trauma Data Bank querying years 2007-2010. Patients with and without vascular injuries were then compared. Admission variables included transport time, emergency department hypotension (systolic blood pressure < 90), Glasgow Coma Scale ≤ 8, Injury Severity Score ≥ 25, fractures, solid organ injury, and vascular injury. Outcomes were analyzed and associations with vascular injuries were determined. A total of 2,298 patients were identified with winter sports-related trauma and 28 (1.2%) had associated vascular injuries. Overall, the top 3 injuries were head trauma (16.7%), thoracic vertebral fractures (5.5%), and lumbar vertebral fractures (5.1%). The most common associated vascular injures were to the popliteal artery (17.7%), splenic artery (14.7%), and brachial blood vessels (14.7%). In the entire cohort, 1 patient (0.04%) suffered an amputation and 15 patients (0.7%) died. There were no amputations in the vascular injury group. Mortality was 0.6% in patients without a vascular injury compared with 7.1% of those with a vascular injury (P = 0.01). Although vascular injury is an uncommon associated finding in winter sports trauma, it is associated with a significant increase in mortality. These findings highlight the need for rapid identification of traumatic vascular injuries, which predicts worse overall outcomes in this patient population. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. How autumn Eurasian snow anomalies affect east asian winter monsoon: a numerical study

    NASA Astrophysics Data System (ADS)

    Luo, Xiao; Wang, Bin

    2018-03-01

    Previous studies have found that snow Eurasian anomalies in autumn can affect East Asian winter monsoon (EAWM), but the mechanisms remain controversial and not well understood. The possible mechanisms by which Eurasian autumn snow anomalies affect EAWM are investigated by numerical experiments with a coupled general circulation model and its atmospheric general circulation model component. The leading empirical orthogonal function mode of the October-November mean Eurasian snow cover is characterized by a uniform anomaly over a broad region of central Eurasia (40°N-65°N, 60°E-140°E). However, the results from a 150-ensemble mean simulation with snow depth anomaly specified in October and November reveal that the Mongolian Plateau and Vicinity (MPV, 40°-55°N, 80°-120°E) is the key region for autumn snow anomalies to affect EAWM. The excessive snow forcing can significantly enhance EAWM and the snowfall over the northwestern China and along the EAWM front zone stretching from the southeast China to Japan. The physical process involves a snow-monsoon feedback mechanism. The excessive autumn snow anomalies over the MPV region can persist into the following winter, and significantly enhance winter snow anomalies, which increase surface albedo, reduce incoming solar radiation and cool the boundary layer air, leading to an enhanced Mongolian High and a deepened East Asian trough. The latter, in turn, strengthen surface northwesterly winds, cooling East Asia and increasing snow accumulation over the MPV region and the southeastern China. The increased snow covers feedback to EAWM system through changing albedo, extending its influence southeastward. It is also found that the atmosphere-ocean coupling process can amplify the delayed influence of Eurasian snow mass anomaly on EAWM. The autumn surface albedo anomalies, however, do not have a lasting "memory" effect. Only if the albedo anomalies are artificially extended into December and January, will the EAWM be

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

    USGS Publications Warehouse

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

    2014-01-01

    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.

  5. 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. Published by Elsevier B.V.

  6. Classification of Snowfall Events and Their Effect on Canopy Interception Efficiency in a Temperate Montane Forest.

    NASA Astrophysics Data System (ADS)

    Roth, T. R.; Nolin, A. W.

    2015-12-01

    Forest canopies intercept as much as 60% of snowfall in maritime environments, while processes of sublimation and melt can reduce the amount of snow transferred from the canopy to the ground. This research examines canopy interception efficiency (CIE) as a function of forest and event-scale snowfall characteristics. We use a 4-year dataset of continuous meteorological measurements and monthly snow surveys from the Forest Elevation Snow Transect (ForEST) network that has forested and open sites at three elevations spanning the rain-snow transition zone to the upper seasonal snow zone. Over 150 individual storms were classified by forest and storm type characteristics (e.g. forest density, vegetation type, air temperature, snowfall amount, storm duration, wind speed, and storm direction). The between-site comparisons showed that, as expected, CIE was highest for the lower elevation (warmer) sites with higher forest density compared with the higher elevation sites where storm temperatures were colder, trees were smaller and forests were less dense. Within-site comparisons based on storm type show that this classification system can be used to predict CIE.Our results suggest that the coupling of forest type and storm type information can improve estimates of canopy interception. Understanding the effects of temperature and storm type in temperate montane forests is also valuable for future estimates of canopy interception under a warming climate.

  7. 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

  8. Application of Snowfall and Wind Statistics to Snow Transport Modeling for Snowdrift Control in Minnesota.

    NASA Astrophysics Data System (ADS)

    Shulski, Martha D.; Seeley, Mark W.

    2004-11-01

    Models were utilized to determine the snow accumulation season (SAS) and to quantify windblown snow for the purpose of snowdrift control for locations in Minnesota. The models require mean monthly temperature, snowfall, density of snow, and wind frequency distribution statistics. Temperature and precipitation data were obtained from local cooperative observing sites, and wind data came from Automated Surface Observing System (ASOS)/Automated Weather Observing System (AWOS) sites in the region. The temperature-based algorithm used to define the SAS reveals a geographic variability in the starting and ending dates of the season, which is determined by latitude and elevation. Mean seasonal snowfall shows a geographic distribution that is affected by topography and proximity to Lake Superior. Mean snowfall density also exhibits variability, with lower-density snow events displaced to higher-latitude positions. Seasonal wind frequencies show a strong bimodal distribution with peaks from the northwest and southeast vector direction, with an exception for locations in close proximity to the Lake Superior shoreline. In addition, for western and south-central Minnesota there is a considerably higher frequency of wind speeds above the mean snow transport threshold of 7 m s-1. As such, this area is more conducive to higher potential snow transport totals. Snow relocation coefficients in this area are in the range of 0.4 0.9, and, according to the empirical models used in this analysis, this range implies that actual snow transport is 40% 90% of the total potential in south-central and western areas of the state.


  9. Carbon dioxide sources from Alaska driven by increasing early winter respiration from Arctic tundra

    PubMed Central

    Lindaas, Jakob; Benmergui, Joshua; Luus, Kristina A.; Chang, Rachel Y.-W.; Daube, Bruce C.; Euskirchen, Eugénie S.; Karion, Anna; Miller, John B.; Miller, Scot M.; Parazoo, Nicholas C.; Randerson, James T.; Sweeney, Colm; Thoning, Kirk; Veraverbeke, Sander; Miller, Charles E.; Wofsy, Steven C.

    2017-01-01

    High-latitude ecosystems have the capacity to release large amounts of carbon dioxide (CO2) to the atmosphere in response to increasing temperatures, representing a potentially significant positive feedback within the climate system. Here, we combine aircraft and tower observations of atmospheric CO2 with remote sensing data and meteorological products to derive temporally and spatially resolved year-round CO2 fluxes across Alaska during 2012–2014. We find that tundra ecosystems were a net source of CO2 to the atmosphere annually, with especially high rates of respiration during early winter (October through December). Long-term records at Barrow, AK, suggest that CO2 emission rates from North Slope tundra have increased during the October through December period by 73% ± 11% since 1975, and are correlated with rising summer temperatures. Together, these results imply increasing early winter respiration and net annual emission of CO2 in Alaska, in response to climate warming. Our results provide evidence that the decadal-scale increase in the amplitude of the CO2 seasonal cycle may be linked with increasing biogenic emissions in the Arctic, following the growing season. Early winter respiration was not well simulated by the Earth System Models used to forecast future carbon fluxes in recent climate assessments. Therefore, these assessments may underestimate the carbon release from Arctic soils in response to a warming climate. PMID:28484001

  10. Carbon dioxide sources from Alaska driven by increasing early winter respiration from Arctic tundra.

    PubMed

    Commane, Róisín; Lindaas, Jakob; Benmergui, Joshua; Luus, Kristina A; Chang, Rachel Y-W; Daube, Bruce C; Euskirchen, Eugénie S; Henderson, John M; Karion, Anna; Miller, John B; Miller, Scot M; Parazoo, Nicholas C; Randerson, James T; Sweeney, Colm; Tans, Pieter; Thoning, Kirk; Veraverbeke, Sander; Miller, Charles E; Wofsy, Steven C

    2017-05-23

    High-latitude ecosystems have the capacity to release large amounts of carbon dioxide (CO 2 ) to the atmosphere in response to increasing temperatures, representing a potentially significant positive feedback within the climate system. Here, we combine aircraft and tower observations of atmospheric CO 2 with remote sensing data and meteorological products to derive temporally and spatially resolved year-round CO 2 fluxes across Alaska during 2012-2014. We find that tundra ecosystems were a net source of CO 2 to the atmosphere annually, with especially high rates of respiration during early winter (October through December). Long-term records at Barrow, AK, suggest that CO 2 emission rates from North Slope tundra have increased during the October through December period by 73% ± 11% since 1975, and are correlated with rising summer temperatures. Together, these results imply increasing early winter respiration and net annual emission of CO 2 in Alaska, in response to climate warming. Our results provide evidence that the decadal-scale increase in the amplitude of the CO 2 seasonal cycle may be linked with increasing biogenic emissions in the Arctic, following the growing season. Early winter respiration was not well simulated by the Earth System Models used to forecast future carbon fluxes in recent climate assessments. Therefore, these assessments may underestimate the carbon release from Arctic soils in response to a warming climate.

  11. Carbon dioxide sources from Alaska driven by increasing early winter respiration from Arctic tundra

    NASA Astrophysics Data System (ADS)

    Commane, Róisín; Lindaas, Jakob; Benmergui, Joshua; Luus, Kristina A.; Chang, Rachel Y.-W.; Daube, Bruce C.; Euskirchen, Eugénie S.; Henderson, John M.; Karion, Anna; Miller, John B.; Miller, Scot M.; Parazoo, Nicholas C.; Randerson, James T.; Sweeney, Colm; Tans, Pieter; Thoning, Kirk; Veraverbeke, Sander; Miller, Charles E.; Wofsy, Steven C.

    2017-05-01

    High-latitude ecosystems have the capacity to release large amounts of carbon dioxide (CO2) to the atmosphere in response to increasing temperatures, representing a potentially significant positive feedback within the climate system. Here, we combine aircraft and tower observations of atmospheric CO2 with remote sensing data and meteorological products to derive temporally and spatially resolved year-round CO2 fluxes across Alaska during 2012-2014. We find that tundra ecosystems were a net source of CO2 to the atmosphere annually, with especially high rates of respiration during early winter (October through December). Long-term records at Barrow, AK, suggest that CO2 emission rates from North Slope tundra have increased during the October through December period by 73% ± 11% since 1975, and are correlated with rising summer temperatures. Together, these results imply increasing early winter respiration and net annual emission of CO2 in Alaska, in response to climate warming. Our results provide evidence that the decadal-scale increase in the amplitude of the CO2 seasonal cycle may be linked with increasing biogenic emissions in the Arctic, following the growing season. Early winter respiration was not well simulated by the Earth System Models used to forecast future carbon fluxes in recent climate assessments. Therefore, these assessments may underestimate the carbon release from Arctic soils in response to a warming climate.

  12. Relevance of future snowfall level height in the Peruvian Andes for glacier loss in the 21st century under different emission scenarios

    NASA Astrophysics Data System (ADS)

    Schauwecker, Simone; Kronenberg, Marlene; Rohrer, Mario; Huggel, Christian; Endries, Jason; Montoya, Nilton; Neukom, Raphael; Perry, Baker; Salzmann, Nadine; Schwarb, Manfred; Suarez, Wilson

    2017-04-01

    In many regions of Peru, the competition for limited hydrological resources already represents a large risk for conflicts. In this context, and within the circumstances of climate change, there is a great interest in estimating the future loss of Peruvian glaciers. Solid precipitation on glaciers, which affects the shortwave radiation budget via its effects on albedo, in general reduces ablation. For that reason, the height of the upper level of the transition zone between liquid and solid precipitation (snowfall level height) is considered to play a critical role. This snowfall level height is linked to air temperature. The observed and projected warming of the atmosphere is therefore affecting the glaciers amongst others by changing the snowfall level height. Despite the potential significance of these changes for Peruvian glaciers, the relations between snowfall level heights, glacier extents and climate scenarios have been poorly investigated so far. In our study, we first analyse the snowfall level heights over the Peruvian Cordilleras. Second, we investigate the relationship between the present snowfall level heights and current glacier extents. As a third step, we derive projected changes of snowfall level heights from GCMs for the RCP2.6 and 8.5 emission scenarios and use them to roughly estimate the end of XXI century glaciation for the Peruvian Cordilleras. Our results indicate a large difference in future glacier extent between the high-emission (pessimistic) RCP8.5 and the low-emission (optimistic) RCP2.6. If global emissions can be substantially reduced, a significant part of the glaciated area of Peru can be maintained. On the contrary, if mitigation is unsuccessful, most of the glacier mass in Peru will be lost during the 21st century. In both cases, but even more so for the high-emission scenario, adaptation will play a critical role and should focus on improvements in water resource management which is essential on a local to regional scale. Air

  13. Projected Influences of Changes in Weather Severity on Autumn-Winter Distributions of Dabbling Ducks in the Mississippi and Atlantic Flyways during the Twenty-First Century

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

    Notaro, Michael; Schummer, Michael; Zhong, Yafang

    Projected changes in the relative abundance and timing of autumn-winter migration are assessed for seven dabbling duck species across the Mississippi and Atlantic Flyways for the mid- and late 21 st century. Species-specific observed relationships are established between cumulative weather severity in autumn-winter and duck population rate of change. Dynamically downscaled projections of weather severity are developed using a high-resolution regional climate model, interactively coupled to a one-dimensional lake model to represent the Great Lakes and associated lake-effect snowfall. Based on the observed relationships and downscaled climate projections of rising air temperatures and reduced snow cover, delayed autumn-winter migration ismore » expected for all species, with the least delays for the Northern Pintail and the greatest delays for the Mallard. Indeed, the Mallard, the most common and widespread duck in North America, may overwinter in the Great Lakes region by the late 21 st century. This highlights the importance of protecting and restoring wetlands across the mid-latitudes of North America, including the Great Lakes Basin, because dabbling ducks are likely to spend more time there, which would impact existing wetlands through increased foraging pressure. Furthermore, inconsistency in the timing and intensity of the traditional autumn-winter migration of dabbling ducks in the Mississippi and Atlantic Flyways could have social and economic consequences to communities to the south, where hunting and birdwatching would be affected.« less

  14. Projected Influences of Changes in Weather Severity on Autumn-Winter Distributions of Dabbling Ducks in the Mississippi and Atlantic Flyways during the Twenty-First Century

    DOE PAGES

    Notaro, Michael; Schummer, Michael; Zhong, Yafang; ...

    2016-12-13

    Projected changes in the relative abundance and timing of autumn-winter migration are assessed for seven dabbling duck species across the Mississippi and Atlantic Flyways for the mid- and late 21 st century. Species-specific observed relationships are established between cumulative weather severity in autumn-winter and duck population rate of change. Dynamically downscaled projections of weather severity are developed using a high-resolution regional climate model, interactively coupled to a one-dimensional lake model to represent the Great Lakes and associated lake-effect snowfall. Based on the observed relationships and downscaled climate projections of rising air temperatures and reduced snow cover, delayed autumn-winter migration ismore » expected for all species, with the least delays for the Northern Pintail and the greatest delays for the Mallard. Indeed, the Mallard, the most common and widespread duck in North America, may overwinter in the Great Lakes region by the late 21 st century. This highlights the importance of protecting and restoring wetlands across the mid-latitudes of North America, including the Great Lakes Basin, because dabbling ducks are likely to spend more time there, which would impact existing wetlands through increased foraging pressure. Furthermore, inconsistency in the timing and intensity of the traditional autumn-winter migration of dabbling ducks in the Mississippi and Atlantic Flyways could have social and economic consequences to communities to the south, where hunting and birdwatching would be affected.« less

  15. 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

  16. 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.

  17. Winter Insulation By Snow Accumulation in a Subarctic Treeline Ecosystem Increases Summer Carbon Cycling Rates

    NASA Astrophysics Data System (ADS)

    Parker, T.; Subke, J. A.; Wookey, P. A.

    2014-12-01

    The effect of snow accumulation on soil carbon and nutrient cycling is attracting substantial attention from researchers. We know that deeper snow accumulation caused by high stature vegetation increases winter microbial activity and therefore carbon and nitrogen flux rates. However, until now the effect of snow accumulation, by buffering winter soil temperature, on subsequent summer soil processes, has scarcely been considered. We carried out an experiment at an alpine treeline in subarctic Sweden in which soil monoliths, contained within PVC collars, were transplanted between forest (deep winter snow) and tundra heath (shallow winter snow). We measured soil CO2efflux over two growing seasons and quantified soil microbial biomass after the second winter. We showed that respiration rates of transplanted forest soil were significantly reduced compared with control collars (remaining in the forest) as a consequence of colder, but more variable, winter temperatures. We hypothesised that microbial biomass would be reduced in transplanted forests soils but found there was no difference compared to control. We therefore further hypothesised that the similarly sized microbial pool in the control is assembled differently to the transplant. We believe that the warmer winters in forests foster more active consortia of decomposer microbes as a result of different abiotic selection pressures. Using an ecosystem scale experimental approach, we have identified a mechanism that influences summer carbon cycling rates based solely on the amount of snow that accumulates the previous winter. We conclude that modification of snow depth as a consequence of changes in vegetation structure is an important mechanism influencing soil C stocks in ecosystems where snow persists for a major fraction of the year.

  18. Effects of maternal characteristics and climatic variation on birth masses of Alaskan caribou

    USGS Publications Warehouse

    Adams, Layne G.

    2005-01-01

    Understanding factors that influence birth mass of mammals provides insights to nutritional trade-offs made by females to optimize their reproduction, growth, and survival. I evaluated variation in birth mass of caribou (Rangifer tarandus) in central Alaska relative to maternal characteristics (age, body mass, cohort, and nutritional condition as influenced by winter severity) during 11 years with substantial variation in winter snowfall. Snowfall during gestation was the predominant factor explaining variation in birth masses, influencing birth mass inversely and through interactions with maternal age and lactation status. Maternal age effects were noted for females ≤ 5 years old, declining in magnitude with each successive age class. Birth mass as a proportion of autumn maternal mass was inversely related to winter snowfall, even though there was no decrease in masses of adult females in late winter associated with severe winters. I found no evidence of a hypothesized intergenerational effect of lower birth masses for offspring of females born after severe winters. Caribou produce relatively small offspring but provide exceptional lactation support for those that survive. Conservative maternal investment before parturition may represent an optimal reproductive strategy given that caribou experience stochastic variation in winter severity during gestation, uncertainty of environmental conditions surrounding the birth season, and intense predation on neonates.

  19. 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

  20. 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.

  1. Demographic consequences of increased winter births in a large aseasonally breeding mammal (Bos taurus) in response to climate change.

    PubMed

    Burthe, Sarah; Butler, Adam; Searle, Kate R; Hall, Stephen J G; Thackeray, Stephen J; Wanless, Sarah

    2011-11-01

    1. Studies examining changes in the scheduling of breeding in response to climate change have focused on species with well-defined breeding seasons. Species exhibiting year-round breeding have received little attention and the magnitudes of any responses are unknown. 2. We investigated phenological data for an enclosed feral population of cattle (Bos taurus L.) in northern England exhibiting year-round breeding. This population is relatively free of human interference. 3. We assessed whether the timing of births had changed over the last 60 years, in response to increasing winter and spring temperatures, changes in herd density, and a regime of lime fertilisation. 4. Median birth date became earlier by 1·0 days per year. Analyses of the seasonal distribution of calving dates showed that significantly fewer calves were born in summer (decline from 44% of total births to 20%) and significantly more in winter (increase from 12% to 30%) over the study period. The most pronounced changes occurred in winter, with significant increases in both the proportion and number of births. Winter births arise from conceptions in the previous spring, and we considered models that investigated climate and weather variables associated with the winter preceding and the spring of conceptions. 5. The proportion of winter births was higher when the onset of the plant growing season was earlier during the spring of conceptions. This relationship was much weaker during years when the site had been fertilised with lime, suggesting that increased forage biomass was over-riding the impacts of changing plant phenology. When the onset of the growing season was late, winter births increased with female density. 6. Recruitment estimates from a stage-structured state-space population model were significantly negatively correlated with the proportion of births in the preceding winter, suggesting that calves born in winter are less likely to survive than those born in other seasons. 7.

  2. Short-Term Forecasts Using NU-WRF for the Winter Olympics 2018

    NASA Technical Reports Server (NTRS)

    Srikishen, Jayanthi; Case, Jonathan L.; Petersen, Walter A.; Iguchi, Takamichi; Tao, Wei-Kuo; Zavodsky, Bradley T.; Molthan, Andrew

    2017-01-01

    The NASA Unified-Weather Research and Forecasting model (NU-WRF) will be included for testing and evaluation in the forecast demonstration project (FDP) of the International Collaborative Experiment -PyeongChang 2018 Olympic and Paralympic (ICE-POP) Winter Games. An international array of radar and supporting ground based observations together with various forecast and now-cast models will be operational during ICE-POP. In conjunction with personnel from NASA's Goddard Space Flight Center, the NASA Short-term Prediction Research and Transition (SPoRT) Center is developing benchmark simulations for a real-time NU-WRF configuration to run during the FDP. ICE-POP observational datasets will be used to validate model simulations and investigate improved model physics and performance for prediction of snow events during the research phase (RDP) of the project The NU-WRF model simulations will also support NASA Global Precipitation Measurement (GPM) Mission ground-validation physical and direct validation activities in relation to verifying, testing and improving satellite-based snowfall retrieval algorithms over complex terrain.

  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. INFLUENCE OF SNOWFALL ON BLOOD LEAD LEVELS OF FREE-FLYING BALD EAGLES (HALIAEETUS LEUCOCEPHALUS) IN THE UPPER MISSISSIPPI RIVER VALLEY.

    PubMed

    Lindblom, Ronald A; Reichart, Letitia M; Mandernack, Brett A; Solensky, Matthew; Schoenebeck, Casey W; Redig, Patrick T

    2017-10-01

    Lead poisoning of scavenging raptors occurs primarily via consumption of game animal carcasses containing lead, which peaks during fall firearm hunting seasons. We hypothesized that snowfall would mitigate exposure by concealing carcasses. We categorized blood lead level (BLL) for a subsample of Bald Eagles (Haliaeetus leucocephalus) from the Upper Mississippi River Valley and described BLL with respect to age, sex, and snowfall. We captured Bald Eagles overwintering in the Upper Mississippi River Valley (n=55) between December 1999 and January 2002. Individual BLL ranged from nondetectable to 335 μg/dL, with 73% of the samples testing positive for acute exposure to lead. Eagle BLL did not significantly differ between age or sex, but levels were higher immediately following the hunting season, and they were lower when the previous month's snowfall was greater than 11 cm. This study suggests a window of time between the white-tailed deer (Odocoileus virginianus) hunting season and the onset of snow when the population experienced peak exposure to lead. Combining these findings with existing research, we offer a narrative of the annual lead exposure cycle of Upper Mississippi River Valley Bald Eagles. These temporal associations are necessary considerations for accurate collection and interpretation of BLL.

  5. Snowfall retrieval at X, Ka and W bands: consistency of backscattering and microphysical properties using BAECC ground-based measurements

    NASA Astrophysics Data System (ADS)

    Tecla Falconi, Marta; von Lerber, Annakaisa; Ori, Davide; Silvio Marzano, Frank; Moisseev, Dmitri

    2018-05-01

    Radar-based snowfall intensity retrieval is investigated at centimeter and millimeter wavelengths using co-located ground-based multi-frequency radar and video-disdrometer observations. Using data from four snowfall events, recorded during the Biogenic Aerosols Effects on Clouds and Climate (BAECC) campaign in Finland, measurements of liquid-water-equivalent snowfall rate S are correlated to radar equivalent reflectivity factors Ze, measured by the Atmospheric Radiation Measurement (ARM) cloud radars operating at X, Ka and W frequency bands. From these combined observations, power-law Ze-S relationships are derived for all three frequencies considering the influence of riming. Using microwave radiometer observations of liquid water path, the measured precipitation is divided into lightly, moderately and heavily rimed snow. Interestingly lightly rimed snow events show a spectrally distinct signature of Ze-S with respect to moderately or heavily rimed snow cases. In order to understand the connection between snowflake microphysical and multi-frequency backscattering properties, numerical simulations are performed by using the particle size distribution provided by the in situ video disdrometer and retrieved ice particle masses. The latter are carried out by using both the T-matrix method (TMM) applied to soft-spheroid particle models with different aspect ratios and exploiting a pre-computed discrete dipole approximation (DDA) database for rimed aggregates. Based on the presented results, it is concluded that the soft-spheroid approximation can be adopted to explain the observed multi-frequency Ze-S relations if a proper spheroid aspect ratio is selected. The latter may depend on the degree of riming in snowfall. A further analysis of the backscattering simulations reveals that TMM cross sections are higher than the DDA ones for small ice particles, but lower for larger particles. The differences of computed cross sections for larger and smaller particles are

  6. Greater effect of increasing shrub height on winter versus summer soil temperature

    NASA Astrophysics Data System (ADS)

    Paradis, Mélissa; Lévesque, Esther; Boudreau, Stéphane

    2016-08-01

    Shrub expansion is increasingly observed in arctic and subarctic environments. The development of shrub structure may significantly impact the abiotic environment at the local scale. Our objective was to reconstruct the development of the vertical structure of Betula glandulosa Michx. and to evaluate its effects on winter and summer soil temperature and on snow depth. Stratified sampling of the shrub revealed that shrub biomass distribution followed a similar pattern in stands of contrasting heights. Woody biomass was maximal in the lower stratum and relatively stable in the intermediate strata, while the foliar biomass tracked the vertical development of the shrub structure. Dendrochronological analysis revealed that shrub stands are relatively young; most of the dominant stems started their development after 1990. Shrub height was positively associated with both the dominant stem age and its vertical growth rate. Temperature differences among sites were greater during winter (ca 10 °C) than during summer (ca 2 °C), while the sum of freezing degree-days varied from 680 °C to 2125 °C. Shrub height was the most plausible variable explaining snow depth, winter ground level temperature and the sum of freezing degree-days. However, woody biomass in the 30-40 cm strata best explained summer ground level temperature. Our results suggest that the development of a shrub structure will have far-reaching consequences on the abiotic environment of subarctic ecosystems.

  7. Winter Storm Jupiter of January 2017: Meteorological Drivers, Synoptic Evolution, and Climate Change Considerations in Portland, Oregon

    NASA Astrophysics Data System (ADS)

    Dean, S.; Loikith, P. C.

    2017-12-01

    Although the Pacific Northwest has some of the highest wintertime precipitation in the United States, most urban areas receive little in the way of snow. While 37 inches of wintertime rain fall in Portland on average annually, the city only receives four inches of snow on average. Although wintertime extreme snowstorm events are rare in Portland, in the last century they have occurred about once every ten years. On January 10-12th, 2017, winter storm Jupiter brought 11 inches of snow to downtown Portland within a 12-hour period, making it the largest snowstorm for the city in twenty years. The city declared a state of emergency, over 30,000 citizens lost power, and thousands of businesses were forced to shut down. The anomalously cold air and high amounts of snowfall in a short amount of time made the storm different from others in recent years. This study aims to discover the meteorological drivers behind the January 2017 snowstorm in Portland, Oregon. We also aim to understand how this storm compared with other local storms in the past, and assess the likelihood of a similar event occurring in the future. To do this, reanalysis data were used to display the synoptic evolution of the January 2017 storm. We compared this storm with two other extreme snowfall events from December 2008 and January 1980, assessing meteorological similarities and differences between storms. Results show that the 2017 event was associated with a slow moving, strong low-pressure system accompanied by a 500 hPa trough. These large-scale features helped drive slow moving, locally heavy snow bands over the city of Portland. At the same time, an unusually strong Arctic high-pressure system moved into the interior Pacific Northwest allowing for strong cold air advection west through the Cascade Mountain Range and Columbia River Gorge. Temperature trends show warming of 1-2 °C in the Pacific Northwest since the middle of the last century. Because of this, uncertainty associated with

  8. NASA Sees Winter's Northeastern U.S. Snowcover Extend Farther South

    NASA Image and Video Library

    2015-02-17

    A winter storm that moved through the Mid-Atlantic on Feb. 16 and 17, 2015 extended the northeastern U.S. snowcover farther south. Until this storm hit, southern New Jersey and southeastern Pennsylvania appeared snow-free on satellite imagery from the previous week. The overnight storm blanketed the entire states of New Jersey and Pennsylvania, as seen on this Feb. 16 image. The image was taken from the MODIS or Moderate Resolution Imaging Spectroradiometer instrument that flies aboard NASA's Terra satellite. The snow cover from the storm actually extended even farther south than the image. Snowfall also blanketed West Virginia, Kentucky, Maryland, Delaware and Virginia, while freezing rain and icy conditions affected the Carolinas, Tennessee and Georgia. On Feb. 17, 2015, NOAA's National Weather Service noted "The winter storm that brought widespread snow, sleet and freezing rain to parts of the south-central U.S. and Mid-Atlantic will wind down as it moves offshore Tuesday. Lingering snow and freezing rain is possible early Tuesday for parts of the Northeast and mid-Atlantic, with rain across parts of the Southeast." Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  9. 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.

  10. Patterns of prey selection by wolves in Denali National Park, Alaska

    USGS Publications Warehouse

    Mech, L. David; Meier, T.J.; Burch, John W.; Adams, Layne G.; Carbyn, Ludwig N.; Fritts, Steven H.; Seip, Dale R.

    1995-01-01

    The patterns of selection by wolves (Canis lupus) preying on moose (Alces alces), caribou (Rangifer tarandus), and Dall sheep (Ovis dalli) in Denali National Park and Preserve, Alaska were studied from 1986 through early 1992. Wolves and their prey are legally protected or relatively unharvested in most of the area, and wolf numbers doubled during the study. Based on remains of 294 moose, 225 caribou, and 63 sheep, wolves killed calves and old adults disproportionately, and individuals with low marrow fat, jaw necrosis, or arthritis. Seasonal trends in proportions of various species, ages, and sex of kills were found. During the winters following winters of deep snowfalls, wolves greatly increased the proportion of caribou cows and calves taken. We conclude that in a natural system, wolves can survive on vulnerable prey even during moderate weather, and when snowfall exceeds average, they can respond by switching to newly vulnerable prey and greatly increasing their numbers.

  11. Modeling Road Vulnerability to Snow Using Mixed Integer Optimization

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

    Rodriguez, Tony K; Omitaomu, Olufemi A; Ostrowski, James A

    As the number and severity of snowfall events continue to grow, the need to intelligently direct road maintenance during these snowfall events will also grow. In several locations, local governments lack the resources to completely treat all roadways during snow events. Furthermore, some governments utilize only traffic data to determine which roads should be treated. As a result, many schools, businesses, and government offices must be unnecessarily closed, which directly impacts the social, educational, and economic well-being of citizens and institutions. In this work, we propose a mixed integer programming formulation to optimally allocate resources to manage snowfall on roadsmore » using meteorological, geographical, and environmental parameters. Additionally, we evaluate the impacts of an increase in budget for winter road maintenance on snow control resources.« less

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

    USDA-ARS?s Scientific Manuscript database

    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...

  13. Changing Waters: Are Climate-Driven Changes in Discharge Regimes Increasing Eutrophication Risk in the Great Lakes Basin?

    NASA Astrophysics Data System (ADS)

    Van Meter, K. J.; Basu, N. B.

    2017-12-01

    In recent decades, the Great Lakes Basin (GLB) has experienced increasing precipitation, warming temperatures, and earlier spring thaws. During this same period, the region has been plagued by problems of water quality, with Lake Erie, in particular, experiencing a re-emergence of major eutrophication events, including an increased incidence of Harmful Algal Blooms. Although the prevailing paradigm is that eutrophication of inland waters is directly correlated with total phosphorus (P) inputs, recent decades have seen a decrease in the total P being delivered to the lakes from contributing watersheds. This apparent disconnect between inputs and outputs, i.e. decreasing P inputs but increased eutrophication, has led some to speculate that loading of total P is an insufficient metric of eutrophication risk and that increasing ratios of soluble reactive P (SRP) in relation to the total P (TP) entering inland water bodies may be a more important driver of algal growth. We hypothesize that changes in seasonal discharge patterns may be contributing to changes in the forms of P being delivered to the lakes, potentially due to changes in delivery pathways-for example surface pathways are more dominant in spring snowmelt, while shallow subsurface and tile pathways are more dominant during winter freeze-thaw events. To test this hypothesis, we have utilized data from more than 200 gaging stations across the GLB to explore the influences of climate and changing hydrologic patterns on biogeochemical processing and transport within the GLB. More specifically, we have asked the following questions: 1) How are discharge patterns changing across the GLB? 2) Are SRP:TP ratios increasing in subwatersheds of the GLB, and what are the spatial patterns in these changes? 3) Are climate-related changes in seasonality, e.g. earlier snowmelt, decreasing snowfall, longer growing seasons, linked to increased ratios of bioavailable P? Our results suggest that changes in precipitation as well

  14. Effect of canopy removal on snowpack quantity and quality, fraser experimental forest, Colorado

    USGS Publications Warehouse

    Stottlemyer, R.; Troendle, C.A.

    2001-01-01

    Snowpack peak water equivalent (PWE), ion concentration, content, and spatial distribution of ion load data from spring 1987-1996 in a 1 ha clearcut and adjacent forested plots vegetated by mature Picea engelmannii and Abies lasiocarpa in the Fraser experimental forest (FEF), Colorado are presented. Our objectives were: (1) to see if a forest opening might redistribute snowfall, snowpack moisture, and snowpack chemical content, and (2) to examine the importance of canopy interception on snowpack quantity and chemistry. On an average, the canopy intercepted 36% of snowfall. Interception was correlated with snowfall amount, snowpack PWE beneath the canopy, and air temperature. Canopy removal increased snowpack PWE to >90% cumulative snowfall inputs. Snowpack K-, H-, and NH4+ concentrations on the clearcut were lower and NO3- higher than in the snowpack beneath the forested plots. Cu mulative snowfall K+ input was less than in the clearcut snowpack; H+ inputs were greater in snowfall than in the snowpack of any plot; and inorganic N (NO3- and NH4+) inputs from snowfall to the clearcut were greater than to the forested plots. Processes accounting for the differences between snowfall inputs and snowpack ion content were leaching of organic debris in the snowpack, differential elution of the snowpack, and canopy retention. There were significant trends by year in snowpack ion content at PWE without similar trends in snowfall inputs. This finding coupled with snowpack ion elution bring into question the use of snowpack chemistry as an indicator of winter atmospheric inputs in short-term studies. ?? 2001 Elsevier Science B.V.

  15. 2009/2010 Eurasian Cold Winter and Loss of Arctic Sea-ice over Barents/Kara Sea

    NASA Astrophysics Data System (ADS)

    Shim, T.; Kim, B.; Kim, S.

    2012-12-01

    In 2009/2010 winter, a few extreme cold events and heavy snowfall occurred over central North America, north western Europe, and East Asia exerting a severe social and economic impacts. In this study, we performed modeling experiments to examine the role of substantially reduced Arctic sea-ice over Barents/Kara Sea on the 2009/2010 cold winters. Although several previous studies investigated cause of the extreme events and emphasized the large snow-covered area over Siberia in autumn 2009, we note that the area extent of Arctic sea-ice over Barents/Kara sea in autumn 2009 was anomalously low and the possible impact from Arctic for the extreme cold events has not been presented. To investigate the influence from the Arctic, we designed three model runs using Community Atmosphere Model Version 3 (CAM3). Each simulation differs by the prescribed surface boundary conditions: (a) CTRL - climatological seasonal cycle of sea surface temperature (SST) and sea-ice concentration (SIC) are prescribed everywhere, (b) EXP_65N - SST and SIC inside the Arctic circle (north of 65°N) are replaced by 2009/2010 values. Elsewhere, the climatology is used, (c) EXP_BK - Same with (b) except that SIC and SST are fixed only over Barents/Kara Sea where the sea-ice area dropped significantly in 2009/2010 winter. Model results from EXP_65N and EXP_BK commonly showed a large increase of air temperature in the lower troposphere where Arctic sea-ice showed a large reduction. Also, compared with the observation, model successfully captured thickened geopotential height in the Arctic and showed downstream wave propagation toward midlatitude. From the analysis, we reveal that this large dipolar Arctic-midlatitude teleconnection pattern in the upper troposphere easily propagate upward and played a role in the weakening of polar vortex. This is also confirmed in the observation. However, the timing of excitation of upward propagating wave in EXP_65N and EXP_BK were different and thus the timing of

  16. Nutrition for winter sports.

    PubMed

    Meyer, Nanna L; Manore, Melinda M; Helle, Christine

    2011-01-01

    Winter sports are played in cold conditions on ice or snow and often at moderate to high altitude. The most important nutritional challenges for winter sport athletes exposed to environmental extremes include increased energy expenditure, accelerated muscle and liver glycogen utilization, exacerbated fluid loss, and increased iron turnover. Winter sports, however, vary greatly regarding their nutritional requirements due to variable physiological and physique characteristics, energy and substrate demands, and environmental training and competition conditions. What most winter sport athletes have in common is a relatively lean physique and high-intensity training periods, thus they require greater energy and nutrient intakes, along with adequate food and fluid before, during, and after training. Event fuelling is most challenging for cross-country skiers competing in long events, ski jumpers aiming to reduce their body weight, and those winter sport athletes incurring repeated qualification rounds and heats. These athletes need to ensure carbohydrate availability throughout competition. Finally, winter sport athletes may benefit from dietary and sport supplements; however, attention should be paid to safety and efficacy if supplementation is considered.

  17. Effects of Planting of Calluna Vulgaris for Stable Snow Accumulation in Winter

    NASA Astrophysics Data System (ADS)

    Ibuki, R.; Harada, K.

    2017-12-01

    Recent year climate of the winter season is changing and the period of snow accumulation is reduced compared with before. It affects the management of the ski resort. Snowfall had occurred in December 2016, but the snow accumulated after January 2017 at the ski resort located in the Pacific Ocean side of the Northeast region of Japan. This situation is thought to be originated from two reasons, one is snow thawing, another is to be blown away by the strong monsoon wind. We are considering utilizing planting to stabilize snow accumulation. Currently building rock gardens with shrubs, mainly Calluna Vulgaris in the ski resort for attracting customers in the summer. These are difficult to raise in the lowlands of Japan because they are too hot, but because of their good growth in relatively low-temperature highlands, it is rare for local residents to appreciate the value of these. In addition, it is excellent in low temperature resistance, and it will not die even under the snow. We investigated the pressure resistance performance due to snowfall and the appropriateness of growth under the weather conditions of the area. Regarding Calluna Vulgaris, Firefly, the plants were not damaged even under snow more than 1 m. In addition, three years have passed since planting, relatively good growth is shown, and the stock has been growing every year. Based on these results, we plan to stabilize the snow accumulation by carrying out planting of Calluna vulgaris inside the slope. The growth of the Calluna species is gentle and the tree height grows only about 50 cm even if 15 years have passed since planting. Therefore, it is considered that the plant body is hard to put out their head on the snow surface during the ski season. Next season will monitor the snow accumulation around the planting area through the snow season.

  18. Tundra water budget and implications of precipitation underestimation.

    PubMed

    Liljedahl, Anna K; Hinzman, Larry D; Kane, Douglas L; Oechel, Walter C; Tweedie, Craig E; Zona, Donatella

    2017-08-01

    Difficulties in obtaining accurate precipitation measurements have limited meaningful hydrologic assessment for over a century due to performance challenges of conventional snowfall and rainfall gauges in windy environments. Here, we compare snowfall observations and bias adjusted snowfall to end-of-winter snow accumulation measurements on the ground for 16 years (1999-2014) and assess the implication of precipitation underestimation on the water balance for a low-gradient tundra wetland near Utqiagvik (formerly Barrow), Alaska (2007-2009). In agreement with other studies, and not accounting for sublimation, conventional snowfall gauges captured 23-56% of end-of-winter snow accumulation. Once snowfall and rainfall are bias adjusted, long-term annual precipitation estimates more than double (from 123 to 274 mm), highlighting the risk of studies using conventional or unadjusted precipitation that dramatically under-represent water balance components. Applying conventional precipitation information to the water balance analysis produced consistent storage deficits (79 to 152 mm) that were all larger than the largest actual deficit (75 mm), which was observed in the unusually low rainfall summer of 2007. Year-to-year variability in adjusted rainfall (±33 mm) was larger than evapotranspiration (±13 mm). Measured interannual variability in partitioning of snow into runoff (29% in 2008 to 68% in 2009) in years with similar end-of-winter snow accumulation (180 and 164 mm, respectively) highlights the importance of the previous summer's rainfall (25 and 60 mm, respectively) on spring runoff production. Incorrect representation of precipitation can therefore have major implications for Arctic water budget descriptions that in turn can alter estimates of carbon and energy fluxes.

  19. A New Inter-Hemispheric Teleconnection Increases Predictability of Winter Precipitation in Southwestern US

    NASA Astrophysics Data System (ADS)

    Mamalakis, A.; Yu, J. Y.; Randerson, J. T.; AghaKouchak, A.; Foufoula-Georgiou, E.

    2017-12-01

    Early and reliable prediction of seasonal precipitation in the southwestern US (SWUS) remains a challenge with significant implications for the economy, water security and ecosystem management of the region. Traditional drivers of winter precipitation in the SWUS have been linked to the El Niño-Southern Oscillation (ENSO), decadal/multidecadal oscillations of the sea surface temperature in northern Pacific and Atlantic oceans, and persistent high-pressure ridges over the Gulf of Alaska. However, ENSO as well as other climate modes exhibit weak statistical relationships with precipitation and low predictability as lead time increases. Grounded on the hypothesis that still undiscovered relationships between large-scale atmosphere-ocean dynamics and SWUS precipitation might exist, here we followed a diagnostic approach by which instead of restricting ourselves to the established teleconnections, we analyzed systematically the correlation of global sea surface temperature (SST) and geopotential height (GPH) with winter precipitation amounts in all climatic divisions in the SWUS, for 1950-2015. Our results show that late-summer persistent SST and GPH anomalies in the subtropical southwestern Pacific are strongly connected with winter precipitation in most climatic divisions, exhibiting higher correlation values than ENSO, and thus increasing the potential for earlier and more accurate precipitation prediction. Cross validation and 30-year running average analysis starting in 1950 suggest an amplification of the detected teleconnections over the past three to four decades. The latter is most likely a result of the reported expansion of the tropics, which has started after the 1980s, and allows SST or GPH variability at lower latitudes to affect the meridional atmospheric circulation. Our work highlights the need to understand the dynamic nature of the coupled atmosphere-ocean system in a changing climate for improving future predictions of regional precipitation.

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

    Treesearch

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

    2004-01-01

    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...

  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. Impacts of Synoptic Weather Patterns on Snow Albedo at Sites in New England

    NASA Astrophysics Data System (ADS)

    Adolph, A. C.; Albert, M. R.; Lazarcik, J.; Dibb, J. E.; Amante, J.; Price, A. N.

    2015-12-01

    Winter snow in the northeastern United States has changed over the last several decades, resulting in shallower snow packs, fewer days of snow cover and increasing precipitation falling as rain in the winter. In addition to these changes which cause reductions in surface albedo, increasing winter temperatures also lead to more rapid snow grain growth, resulting in decreased snow reflectivity. We present in-situ measurements and analyses to test the sensitivity of seasonal snow albedo to varying weather conditions at sites in New England. In particular, we investigate the impact of temperature on snow albedo through melt and grain growth, the impact of precipitation event frequency on albedo through snow "freshening," and the impact of storm path on snow structure and snow albedo. Over three winter seasons between 2013 and 2015, in-situ snow characterization measurements were made at three non-forested sites across New Hampshire. These near-daily measurements include spectrally resolved albedo, snow optical grain size determined through contact spectroscopy, snow depth, snow density and local meteorological parameters. Combining this information with storm tracks derived from HYSPLIT modeling, we quantify the current sensitivity of northeastern US snow albedo to temperature as well as precipitation type, frequency and path. Our analysis shows that southerly winter storms result in snow with a significantly lower albedo than storms which come from across the continental US or the Atlantic Ocean. Interannual variability in temperature and statewide spatial variability in snowfall rates at our sites show the relative importance of snowfall amount and temperatures in albedo evolution over the course of the winter.

  3. Direct observations of atmosphere - sea ice - ocean interactions during Arctic winter and spring storms

    NASA Astrophysics Data System (ADS)

    Graham, R. M.; Itkin, P.; Granskog, M. A.; Assmy, P.; Cohen, L.; Duarte, P.; Doble, M. J.; Fransson, A.; Fer, I.; Fernandez Mendez, M.; Frey, M. M.; Gerland, S.; Haapala, J. J.; Hudson, S. R.; Liston, G. E.; Merkouriadi, I.; Meyer, A.; Muilwijk, M.; Peterson, A.; Provost, C.; Randelhoff, A.; Rösel, A.; Spreen, G.; Steen, H.; Smedsrud, L. H.; Sundfjord, A.

    2017-12-01

    To study the thinner and younger sea ice that now dominates the Arctic the Norwegian Young Sea ICE expedition (N-ICE2015) was launched in the ice-covered region north of Svalbard, from January to June 2015. During this time, eight local and remote storms affected the region and rare direct observations of the atmosphere, snow, ice and ocean were conducted. Six of these winter storms passed directly over the expedition and resulted in air temperatures rising from below -30oC to near 0oC, followed by abrupt cooling. Substantial snowfall prior to the campaign had already formed a snow pack of approximately 50 cm, to which the February storms contributed an additional 6 cm. The deep snow layer effectively isolated the ice cover and prevented bottom ice growth resulting in low brine fluxes. Peak wind speeds during winter storms exceeded 20 m/s, causing strong snow re-distribution, release of sea salt aerosol and sea ice deformation. The heavy snow load caused widespread negative freeboard; during sea ice deformation events, level ice floes were flooded by sea water, and at least 6-10 cm snow-ice layer was formed. Elevated deformation rates during the most powerful winter storms damaged the ice cover permanently such that the response to wind forcing increased by 60 %. As a result of a remote storm in April deformation processes opened about 4 % of the total area into leads with open water, while a similar amount of ice was deformed into pressure ridges. The strong winds also enhanced ocean mixing and increased ocean heat fluxes three-fold in the pycnocline from 4 to 12 W/m2. Ocean heat fluxes were extremely large (over 300 W/m2) during storms in regions where the warm Atlantic inflow is located close to surface over shallow topography. This resulted in very large (5-25 cm/day) bottom ice melt and in cases flooding due to heavy snow load. Storm events increased the carbon dioxide exchange between the atmosphere and ocean but also affected the pCO2 in surface waters

  4. Satellites see major winter storm marching toward the U.S. East Coast

    NASA Image and Video Library

    2017-12-08

    NASA and NOAA satellites are providing various views of the major winter storm marching toward the U.S. East coast on March 13. The storm is forecast to merge with another system and is expected to bring large snowfall totals from the Mid-Atlantic to New England. NASA's Aqua satellite gathered infrared data from the storm system and the area ahead of the storm for cloud and ground temperatures. NOAA's GOES-East satellite provided visible and infrared imagery that showed the extent and the movement of the system. Forecasters at the National Weather Service's Weather Prediction Center (WPC) noted that the low pressure system crossing the Midwest states and Ohio Valley is expected to merge with another low off the southeast U.S. coast. WPC stated "This will allow for a strong nor'easter to develop near the coast and cause a late-season snowstorm from the central Appalachians to New England, including many of the big cities in the Northeast U.S." Credits: NASA/NOAA GOES Project

  5. Tundra water budget and implications of precipitation underestimation

    PubMed Central

    Hinzman, Larry D.; Kane, Douglas L.; Oechel, Walter C.; Tweedie, Craig E.; Zona, Donatella

    2017-01-01

    Abstract Difficulties in obtaining accurate precipitation measurements have limited meaningful hydrologic assessment for over a century due to performance challenges of conventional snowfall and rainfall gauges in windy environments. Here, we compare snowfall observations and bias adjusted snowfall to end‐of‐winter snow accumulation measurements on the ground for 16 years (1999–2014) and assess the implication of precipitation underestimation on the water balance for a low‐gradient tundra wetland near Utqiagvik (formerly Barrow), Alaska (2007–2009). In agreement with other studies, and not accounting for sublimation, conventional snowfall gauges captured 23–56% of end‐of‐winter snow accumulation. Once snowfall and rainfall are bias adjusted, long‐term annual precipitation estimates more than double (from 123 to 274 mm), highlighting the risk of studies using conventional or unadjusted precipitation that dramatically under‐represent water balance components. Applying conventional precipitation information to the water balance analysis produced consistent storage deficits (79 to 152 mm) that were all larger than the largest actual deficit (75 mm), which was observed in the unusually low rainfall summer of 2007. Year‐to‐year variability in adjusted rainfall (±33 mm) was larger than evapotranspiration (±13 mm). Measured interannual variability in partitioning of snow into runoff (29% in 2008 to 68% in 2009) in years with similar end‐of‐winter snow accumulation (180 and 164 mm, respectively) highlights the importance of the previous summer's rainfall (25 and 60 mm, respectively) on spring runoff production. Incorrect representation of precipitation can therefore have major implications for Arctic water budget descriptions that in turn can alter estimates of carbon and energy fluxes. PMID:29081549

  6. Synoptic characteristics of heavy snowfalls at Busan of Korea caused by polar lows over the East/Japan Sea

    NASA Astrophysics Data System (ADS)

    Choi, Jae-Won; Cha, Yumi; Kim, Hae-Dong

    2018-02-01

    The results of the present study prove that snowfall occurred due to the polar low (PL) in the Korean Peninsula and six cases of snowfall exceeding a snow depth of 2 cm over the past 16 years in Busan, South Korea. A strong northwesterly air current with a cold outbreak at the lower level passed through the Korean Peninsula and penetrated into the East/Japan Sea causing the generation and characteristics of a PL. However, a northeasterly air current due to a synoptic low (SL) in East Japan approached the east coast via the East/Japan Sea, which generated a wind field with mesoscale cyclonic circulation. In the center of this cyclone, a strong positive vorticity region was revealed from the lower level to the upper level. The air temperature in the center of the PL was warmer than the surrounding areas at the lower level. As the PL developed and the air temperature decreased, a rapid tropopause drop followed due to the effect of the cold core along with the cutoff low at the mid-level or the higher level. As a result, the stratification became more unstable. The PL moved into Busan as the cold core at the upper level rapidly moved to the lower latitudes, which formed an unstable region around Busan. The PL decayed because the cutoff low, the cold core, and the positive vorticity region at the upper level quickly moved to the east, thereby causing the stratification to stabilize. Also, because the approach to the Japanese Archipelago caused an increase in surface friction, the original structure could no longer be maintained.

  7. 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.

  8. Dissolved organic matter composition of winter flow in the Yukon River basin: Implications of permafrost thaw and increased groundwater discharge

    USGS Publications Warehouse

    O'Donnell, Jonathan A.; Aiken, George R.; Walvoord, Michelle Ann; Butler, Kenna D.

    2012-01-01

    Groundwater discharge to rivers has increased in recent decades across the circumpolar region and has been attributed to thawing permafrost in arctic and subarctic watersheds. Permafrost-driven changes in groundwater discharge will alter the flux of dissolved organic carbon (DOC) in rivers, yet little is known about the chemical composition and reactivity of dissolved organic matter (DOM) of groundwater in permafrost settings. Here, we characterize DOM composition of winter flow in 60 rivers and streams of the Yukon River basin to evaluate the biogeochemical consequences of enhanced groundwater discharge associated with permafrost thaw. DOC concentration of winter flow averaged 3.9 ± 0.5 mg C L−1, yet was highly variable across basins (ranging from 20 mg C L−1). In comparison to the summer-autumn period, DOM composition of winter flow had lower aromaticity (as indicated by specific ultraviolet absorbance at 254 nm, or SUVA254), lower hydrophobic acid content, and a higher proportion of hydrophilic compounds (HPI). Fluorescence spectroscopy and parallel factor analysis indicated enrichment of protein-like fluorophores in some, but not all, winter flow samples. The ratio of DOC to dissolved organic nitrogen, an indicator of DOM biodegradability, was positively correlated with SUVA254 and negatively correlated with the percentage of protein-like compounds. Using a simple two-pool mixing model, we evaluate possible changes in DOM during the summer-autumn period across a range of conditions reflecting possible increases in groundwater discharge. Across three watersheds, we consistently observed decreases in DOC concentration and SUVA254 and increases in HPI with increasing groundwater discharge. Spatial patterns in DOM composition of winter flow appear to reflect differences in the relative contributions of groundwater from suprapermafrost and subpermafrost aquifers across watersheds. Our findings call for more explicit consideration of DOC loss and stabilization

  9. Similarities and differences between three coexisting spaceborne radars in global rainfall and snowfall estimation

    NASA Astrophysics Data System (ADS)

    Tang, Guoqiang; Wen, Yixin; Gao, Jinyu; Long, Di; Ma, Yingzhao; Wan, Wei; Hong, Yang

    2017-05-01

    Precipitation is one of the most important components in the water and energy cycles. Radars are considered the best available technology for observing the spatial distribution of precipitation either from the ground since the 1980s or from space since 1998. This study, for the first time ever, compares and evaluates the only three existing spaceborne precipitation radars, i.e., the Ku-band precipitation radar (PR), the W-band Cloud Profiling Radar (CPR), and the Ku/Ka-band Dual-frequency Precipitation Radar (DPR). The three radars are matched up globally and intercompared in the only period which they coexist: 2014-2015. In addition, for the first time ever, TRMM PR and GPM DPR are evaluated against hourly rain gauge data in Mainland China. Results show that DPR and PR agree with each other and correlate very well with gauges in Mainland China. However, both show limited performance in the Tibetan Plateau (TP) known as the Earth's third pole. DPR improves light precipitation detectability, when compared with PR, whereas CPR performs best for light precipitation and snowfall. DPR snowfall has the advantage of higher sampling rates than CPR; however, its accuracy needs to be improved further. The future development of spaceborne radars is also discussed in two complementary categories: (1) multifrequency radar instruments on a single platform and (2) constellations of many small cube radar satellites, for improving global precipitation estimation. This comprehensive intercomparison of PR, CPR, and DPR sheds light on spaceborne radar precipitation retrieval and future radar design.

  10. [Freezing resistance and injury indices for different cultivars of winter-spring wheat in Huang-Huai-Hai Plain. I . Comparison of freezing resistance for different cultivars of winter-spring wheat during mid-winter period].

    PubMed

    Mu, Cheng-ying; Yang, Xiao-guang; Yang, Jie; Li, Ke-nan; Zheng, Dong-xiao

    2015-10-01

    The relationships between mortality rate and low temperature for different cultivars of winter-spring wheat during mid-winter period were identified through two-year outdoor potting experiments and indoor manually controlled freezing experiments. We defined the lethally critical temperature and the density of antifreeze capability when the mortality rate reached 10%, 20% and 50% for different cultivars of winter-spring wheat during mid-winter period. The strong-winterness wheat (Yanda 1817 and Jing 411) showed the best freezing resistance and the 50%-lethal temperatures (LT50) of these two cultivars were -21.5 °C and -21.2 °C, respectively. The freezing resistance of winterness wheat and weak-winternes wheat were worse than that of strong-winterness wheat. The LT50 of winterness wheat cultivars Nongda 211 and Nongda 5363 were -21.1 °C and -20.3 °C, while that of weak-winterness wheat cultivars Zheng 366 and Ping' an 8 were -18.5 °C and -18.4 °C , respectively. Springness wheat (Zheng 9023 and Yanzhan 4110) showed the worst freezing resistance, and the LT50 were -15.4 °C and -14.7 °C, respectively. When temperature declined to freezing injury occurred, mortality rate increment for weak-winterness wheat was the highest for each 1 °C decrease. The mortality rates of weak-winterness wheat cultivars Zheng 366 and Ping' an 8 increased by 16.8% and 25.8%, and that of winterness wheat cultivars Nongda 211 and Nongda 5363 increased by 14.7% and 18.9%. The mortality rate of strong-winterness wheat cultivars Yanda 1817 and Jing 411 increased by 15.4% and 13.1%, and that of springiness wheat cultivas Zheng 9023 and Yanzhan 4110 increased by 13.8% and 15.1%. Comparatively, if temperature decreased continuously after the occurrence of freezing injury, the weak-winterness wheat would suffer greater risk.

  11. Operational Lessons Learned in the Korean War

    DTIC Science & Technology

    2011-12-01

    per response, including the time for reviewing instructions, searching existing data sources , gathering and maintaining the data needed, and...marines and soldiers faced sub-zero temperatures and heavy snowfall that blocked mountain passes and clogged main supply routes. Fifty years later...soldiers and airmen serving in Korea experienced another such harsh winter that limited operations because of heavy snowfall and had an impact their

  12. 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.

  13. Variation and BLUPs in a novel source of orchardgrass germplasm with increased winter hardiness

    USDA-ARS?s Scientific Manuscript database

    The production potential of orchardgrass (Dactylis glomerata L.) is limited by winter injury at high latitudes and elevations. Evaluation of orchardgrass families at two Utah (US) locations identified significant genetic variation for two measures of tolerance to winter injury, but not for flowering...

  14. 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.

  15. 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

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

    USDA-ARS?s Scientific Manuscript database

    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...

  17. Prevalence of operator fatigue in winter maintenance operations.

    PubMed

    Camden, Matthew C; Medina-Flintsch, Alejandra; Hickman, Jeffrey S; Bryce, James; Flintsch, Gerardo; Hanowski, Richard J

    2018-02-02

    Similar to commercial motor vehicle drivers, winter maintenance operators are likely to be at an increased risk of becoming fatigued while driving due to long, inconsistent shifts, environmental stressors, and limited opportunities for sleep. Despite this risk, there is little research concerning the prevalence of winter maintenance operator fatigue during winter emergencies. The purpose of this research was to investigate the prevalence, sources, and countermeasures of fatigue in winter maintenance operations. Questionnaires from 1043 winter maintenance operators and 453 managers were received from 29 Clear Road member states. Results confirmed that fatigue was prevalent in winter maintenance operations. Over 70% of the operators and managers believed that fatigue has a moderate to significant impact on winter maintenance operations. Approximately 75% of winter maintenance operators reported to at least sometimes drive while fatigued, and 96% of managers believed their winter maintenance operators drove while fatigued at least some of the time. Furthermore, winter maintenance operators and managers identified fatigue countermeasures and sources of fatigue related to winter maintenance equipment. However, the countermeasures believed to be the most effective at reducing fatigue during winter emergencies (i.e., naps) were underutilized. For example, winter maintenance operators reported to never use naps to eliminate fatigue. These results indicated winter maintenance operations are impacted by operator fatigue. These results support the increased need for research and effective countermeasures targeting winter maintenance operator fatigue. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Reduced irrigation increases the water use efficiency and productivity of winter wheat-summer maize rotation on the North China Plain.

    PubMed

    Wang, Yunqi; Zhang, Yinghua; Zhang, Rui; Li, Jinpeng; Zhang, Meng; Zhou, Shunli; Wang, Zhimin

    2018-03-15

    The groundwater table has fallen sharply over the last 30years on the North China Plain, resulting in a shortage of water for winter wheat irrigation. Reducing irrigation may be an important strategy to maintain agricultural sustainability in the region; however, few studies have evaluated the transition from conventional irrigation management practices to reduced irrigation management practices in the winter wheat-summer maize rotation system. Here, we compare the yield, water consumption, and water use efficiency of winter wheat-summer maize rotation under conventional irrigation and reduced irrigation on the North China Plain from 2012 to 2015. Reducing irrigation decreased the yield but increased the water use efficiency and significantly advanced the harvest date of winter wheat. As a result, the summer maize sowing date advanced significantly, and the flowering date subsequently advanced 2-8days, thus extending the summer maize grain-filling stage. Therefore, the yield and water use efficiency of summer maize were higher under reduced irrigation than conventional irrigation, which compensated for the winter wheat yield loss under reduced irrigation. In addition, under reduced irrigation from 2012 to 2015, the yield and water use efficiency advantage of the winter wheat-summer maize rotation ranged from 0.0 to 9.7% and from 4.1 to 14.7%, respectively, and water consumption and irrigated water decreased by 20-61mm and 150mm, respectively, compared to conventional irrigation. Overall, the reduced irrigation management practice involving no irrigation after sowing winter wheat, and sowing summer maize on June 7 produced the most favorable grain yield with superb water use efficiency in the winter wheat-summer maize rotation. This study indicates that reducing irrigation could be an efficient means to cope with water resource shortages while maintaining crop production sustainability on the North China Plain. Copyright © 2017. Published by Elsevier B.V.

  19. Excess mortality in winter in Finnish intensive care.

    PubMed

    Reinikainen, M; Uusaro, A; Ruokonen, E; Niskanen, M

    2006-07-01

    In the general population, mortality from acute myocardial infarctions, strokes and respiratory causes is increased in winter. The winter climate in Finland is harsh. The aim of this study was to find out whether there are seasonal variations in mortality rates in Finnish intensive care units (ICUs). We analysed data on 31,040 patients treated in 18 Finnish ICUs. We measured severity of illness with acute physiology and chronic health evaluation II (APACHE II) scores and intensity of care with therapeutic intervention scoring system (TISS) scores. We assessed mortality rates in different months and seasons and used logistic regression analysis to test the independent effect of various seasons on hospital mortality. We defined 'winter' as the period from December to February, inclusive. The crude hospital mortality rate was 17.9% in winter and 16.4% in non-winter, P = 0.003. Even after adjustment for case mix, winter season was an independent risk factor for increased hospital mortality (adjusted odds ratio 1.13, 95% confidence interval 1.04-1.22, P = 0.005). In particular, the risk of respiratory failure was increased in winter. Crude hospital mortality was increased during the main holiday season in July. However, the severity of illness-adjusted risk of death was not higher in July than in other months. An increase in the mean daily TISS score was an independent predictor of increased hospital mortality. Severity of illness-adjusted hospital mortality for Finnish ICU patients is higher in winter than in other seasons.

  20. Reproductive performance of female Alaskan caribou

    USGS Publications Warehouse

    Adams, Layne G.; Dale, Bruce W.

    1998-01-01

    We examined the reproductive performance of female caribou (Rangifer tarandus granti) in relation to age, physical condition, and reproductive experience for 9 consecutive years (1987-95) at Denali National Park, Alaska, during a period of wide variation in winter snowfall. Caribou in Denali differed from other cervid populations where reproductive performance has been investigated, because they occur at low densities (≥0.3/km2) and experience high losses of young to predation. Females first gave birth at 2-6 years old; 56% of these females were 3 years old. Average annual natality rates increased from 27% for 2-year-olds to 100% for 7-year-olds, remained high for 7-13-year-olds (98%), and then declined for females ≥14 years old. Females ≥2 years old that failed to reproduce were primarily sexually immature (76%). Reproductive pauses of sexually mature females occurred predominantly in young (3-6 yr old) and old (≥14 yr old) females. Natality increased with body mass for 10-month-old females weighed 6 months prior to the autumn breeding season (P = 0.007), and for females >1 year old and weighed during autumn (late Sep-early Nov; P = 0.003). Natality for 2-, 3-, 4-, and 6-year-olds declined with increasing late-winter snowfall (Feb-May; P ≤ 0.039) during the winter prior to breeding. In most years, a high percentage of sexually mature females reproduced, and lactation status at the time of breeding did not influence productivity the following year. However, following particularly high snowfall during February-September 1992, productivity was reduced in 1993 for cows successfully rearing calves to autumn the previous year. High losses of calves to predators in 1992 may have increased productivity in 1993. Losses of young-of-the-year to predation prior to the annual breeding season can be an important influence on subsequent productivity for ungulate populations where productivity varies with lactation status of females at the time of breeding.

  1. Waterbirds foods in winter-managed ricefields in Mississippi

    USGS Publications Warehouse

    Manley, S.W.; Kaminski, R.M.; Reinecke, K.J.; Gerard, P.D.

    2004-01-01

    Ricefields are important foraging habitats for waterfowl and other waterbirds in primary North American wintering regions. We conducted a large-scale experiment to test effects of post-harvest ricefield treatment, winter water management, and temporal factors on availabilities of rice, moist-soil plant seeds, aquatic invertebrates, and green forage in the Mississippi Alluvial Valley (MAV), Mississippi, USA, fall-winter 1995-1997. Our results revealed that a large decrease in rice grain occurred between harvest and early winter (79-99%), which, if generally true throughout the MAV, would have critical implications on foraging carrying capacity of ricefields for migrating and wintering waterbirds. During the remainder of winter, food resources generally were similar among treatment combinations. An exception was biomass of aquatic invertebrates, which demonstrated potential to increase by late winter in ricefields that remained flooded. We offer revised calculations of foraging carrying capacity for waterfowl in MAV ricefields and recommend continuing research and management designed to increase availability of residual rice and aquatic invertebrates in winter.

  2. 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

  3. Resilience to Changing Snow Depth in a Shrubland Ecosystem.

    NASA Astrophysics Data System (ADS)

    Loik, M. E.

    2008-12-01

    Snowfall is the dominant hydrologic input for high elevations and latitudes of the arid- and semi-arid western United States. Sierra Nevada snowpack provides numerous important services for California, but is vulnerable to anthropogenic forcing of the coupled ocean-atmosphere system. GCM and RCM scenarios envision reduced snowpack and earlier melt under a warmer climate, but how will these changes affect soil and plant water relations and ecosystem processes? And, how resilient will this ecosystem be to short- and long-term forcing of snow depth and melt timing? To address these questions, our experiments utilize large- scale, long-term roadside snow fences to manipulate snow depth and melt timing in eastern California, USA. Interannual snow depth averages 1344 mm with a CV of 48% (April 1, 1928-2008). Snow fences altered snow melt timing by up to 18 days in high-snowfall years, and affected short-term soil moisture pulses less in low- than medium- or high-snowfall years. Sublimation in this arid location accounted for about 2 mol m- 2 of water loss from the snowpack in 2005. Plant water potential increased after the ENSO winter of 2005 and stayed relatively constant for the following three years, even after the low snowfall of winter 2007. Over the long-term, changes in snow depth and melt timing have impacted cover or biomass of Achnatherum thurberianum, Elymus elemoides, and Purshia tridentata. Growth of adult conifers (Pinus jeffreyi and Pi. contorta) was not equally sensitive to snow depth. Thus, complex interactions between snow depth, soil water inputs, physiological processes, and population patterns help drive the resilience of this ecosystem to changes in snow depth and melt timing.

  4. American woodcock winter distribution and fidelity to wintering areas

    USGS Publications Warehouse

    Diefenbach, D.R.; Derleth, E.L.; Vander Haegen, W. Matthew; 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 ares. 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.

  5. Climate change impacts on hillslope runoff on the northern Great Plains, 1962-2013

    NASA Astrophysics Data System (ADS)

    Coles, A. E.; McConkey, B. G.; McDonnell, J. J.

    2017-07-01

    On the Great Plains of North America, water resources are being threatened by climatic shifts. However, a lack of hillslope-scale climate-runoff observations is limiting our ability to understand these impacts. Here, we present a 52-year (1962-2013) dataset (precipitation, temperature, snow cover, soil water content, and runoff) from three 5 ha hillslopes on the seasonally-frozen northern Great Plains. In this region, snowmelt-runoff drives c. 80% of annual runoff and is potentially vulnerable to warming temperatures and changes in precipitation amount and phase. We assessed trends in these climatological and hydrological variables using time series analysis. We found that spring snowmelt-runoff has decreased (on average by 59%) in response to a reduction in winter snowfall (by 18%), but that rainfall-runoff has shown no significant response to a 51% increase in rainfall or shifts to more multi-day rain events. In summer, unfrozen, deep, high-infiltrability soils act as a 'shock absorber' to rainfall, buffering the long-term runoff response to rainfall. Meanwhile, during winter and spring freshet, frozen ground limits soil infiltrability and results in runoff responses that more closely mirror the snowfall and snowmelt trends. These findings are counter to climate-runoff relationships observed at the catchment scale on the northern Great Plains where land drainage alterations dominate. At the hillslope scale, decreasing snowfall, snowmelt-runoff, and spring soil water content is causing agricultural productivity to be increasingly dependent on growing season precipitation, and will likely accentuate the impact of droughts.

  6. Do hospital admission rates increase in colder winters? A decadal analysis from an eastern county in England.

    PubMed

    Patterson, Stephen

    2017-07-05

    The aim of the study was to measure the effect of colder winters compared to warmer winters on hospital admission rates in Suffolk County. The setting of this study was Suffolk County in eastern England. The period of the study was financial years 2003/04-2012/13. The study was an analytic ecological study. Analysis involved calculation of rate ratios of hospital admission rates in colder winters compared to warmer winters, in all persons and the elderly. The main finding of the study was that all rate ratios for hospital admission rates in colder winters compared to warmer winters were significantly raised with effects of 2-5%. Rate ratios for all admissions in persons of all ages and persons aged 65 years and over were, respectively, 1.02 (99% confidence interval (CI): 1.01, 1.03; P < 0.001) and 1.02 (99% CI: 1.01, 1.04; P < 0.001). Rate ratios for emergency admissions in persons of all ages and persons aged 65 years and over were, respectively, 1.05 (99% CI: 1.03, 1.06; P < 0.001) and 1.04 (99% CI: 1.01, 1.06; P < 0.001). In Suffolk County, hospital admission rates are significantly raised in colder winters compared to warmer winters. This evidence may be useful in planning hospital services. © The Author 2017. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  7. 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

  8. Increasing persistent haze in Beijing: potential impacts of weakening East Asian winter monsoons associated with northwestern Pacific sea surface temperature trends

    NASA Astrophysics Data System (ADS)

    Pei, Lin; Yan, Zhongwei; Sun, Zhaobin; Miao, Shiguang; Yao, Yao

    2018-03-01

    Over the past decades, Beijing, the capital city of China, has encountered increasingly frequent persistent haze events (PHE). While the increased pollutant emissions are considered as the most important reason, changes in regional atmospheric circulations associated with large-scale climate warming also play a role. In this study, we find a significant positive trend of PHE in Beijing for the winters from 1980 to 2016 based on updated daily observations. This trend is closely related to an increasing frequency of extreme anomalous southerly episodes in North China, a weakened East Asian trough in the mid-troposphere and a northward shift of the East Asian jet stream in the upper troposphere. These conditions together depict a weakened East Asian winter monsoon (EAWM) system, which is then found to be associated with an anomalous warm, high-pressure system in the middle-lower troposphere over the northwestern Pacific. A practical EAWM index is defined as the seasonal meridional wind anomaly at 850 hPa in winter over North China. Over the period 1900-2016, this EAWM index is positively correlated with the sea surface temperature anomalies over the northwestern Pacific, which indicates a wavy positive trend, with an enhanced positive phase since the mid-1980s. Our results suggest an observation-based mechanism linking the increase in PHE in Beijing with large-scale climatic warming through changes in the typical regional atmospheric circulation.

  9. Investigating Mars South Residual CO2 Cap with a Global Climate Model

    NASA Technical Reports Server (NTRS)

    Kahre, M. A.; Dequaire, J.; Hollingsworth, J. L.; Haberle, R. M.

    2016-01-01

    The CO2 cycle is one of the three controlling climate cycles on Mars. One aspect of the CO2 cycle that is not yet fully understood is the existence of a residual CO2 ice cap that is offset from the south pole. Previous investigations suggest that the atmosphere may control the placement of the south residual cap (e.g., Colaprete et al., 2005). These investigations show that topographically forced stationary eddies in the south during southern hemisphere winter produce colder atmospheric temperatures and increased CO2 snowfall over the hemisphere where the residual cap resides. Since precipitated CO2 ice produces higher surface albedos than directly deposited CO2 ice, it is plausible that CO2 snowfall resulting from the zonally asymmetric atmospheric circulation produces surface ice albedos high enough to maintain a residual cap only in one hemisphere. The goal of the current work is to further evaluate Colaprete et al.'s hypothesis by investigating model-predicted seasonally varying snowfall patterns in the southern polar region and the atmospheric circulation components that control them.

  10. Projecting the future of an alpine ungulate under climate change scenarios.

    PubMed

    White, Kevin S; Gregovich, David P; Levi, Taal

    2018-03-01

    Climate change represents a primary threat to species persistence and biodiversity at a global scale. Cold adapted alpine species are especially sensitive to climate change and can offer key "early warning signs" about deleterious effects of predicted change. Among mountain ungulates, survival, a key determinant of demographic performance, may be influenced by future climate in complex, and possibly opposing ways. Demographic data collected from 447 mountain goats in 10 coastal Alaska, USA, populations over a 37-year time span indicated that survival is highest during low snowfall winters and cool summers. However, general circulation models (GCMs) predict future increase in summer temperature and decline in winter snowfall. To disentangle how these opposing climate-driven effects influence mountain goat populations, we developed an age-structured population model to project mountain goat population trajectories for 10 different GCM/emissions scenarios relevant for coastal Alaska. Projected increases in summer temperature had stronger negative effects on population trajectories than the positive demographic effects of reduced winter snowfall. In 5 of the 10 GCM/representative concentration pathway (RCP) scenarios, the net effect of projected climate change was extinction over a 70-year time window (2015-2085); smaller initial populations were more likely to go extinct faster than larger populations. Using a resource selection modeling approach, we determined that distributional shifts to higher elevation (i.e., "thermoneutral") summer range was unlikely to be a viable behavioral adaptation strategy; due to the conical shape of mountains, summer range was expected to decline by 17%-86% for 7 of the 10 GCM/RCP scenarios. Projected declines of mountain goat populations are driven by climate-linked bottom-up mechanisms and may have wide ranging implications for alpine ecosystems. These analyses elucidate how projected climate change can negatively alter population

  11. Effect assessment of Future Climate Change on Water Resource and Snow Quality in cold snowy regions in Japan

    NASA Astrophysics Data System (ADS)

    Taniguchi, Y.; Nakatsugawa, M.; Kudo, K.

    2017-12-01

    It is predicted that the effects of global warming on everyday life will be clearly seen in cold, snowy regions such as Hokkaido. In relation to climate change, there is the concern that the warmer climate will affect not only water resources, but also local economies, in snowy areas, when air temperature increases and snowfall decreases become more marked in the future. Communities whose economies are greatly dependent on snow as a tourism resource, such as for winter sports and snow events, will lose large numbers of visitors because of the shortened winter season. This study was done as a basic study to provide basic ideas for planning adaptation strategies against climate change based on the local characteristics of a cold, snowy region. By taking dam catchment basins in Hokkaido as the subject areas and by using the climate change prediction data that correspond to IPCCAR5, the local-level influence of future climate change on snowfall and snow quality in relation to water resources and winter sports was quantitatively assessed. The water budget was examined for a dam catchment basin in Hokkaido under the present climate (September 1984 to August 2004) and under the future climate (September 2080 to August 2100) by using rainfall, snowfall and evapotranspiration estimated by the LoHAS heat and water balance analysis model.The examination found that, under the future climate, the net annual precipitation will decrease by up to 200 mm because of decreases in precipitation and in runoff height that will result from increased evapotranspiration. The predicted decrease in annual hydro potential of snowfall was considered to greatly affect the dam reservoir operation during the snowmelt season. The snow quality analysis by SNOWPACK revealed that the future snow would become granular earlier than it does at present. Most skiers' snow preferences, from best to worst, are light dry snow (i.e., fresh snow), lightly compacted snow, compacted snow and, finally, granular

  12. Improved antioxidative protection in winter swimmers.

    PubMed

    Siems, W G; Brenke, R; Sommerburg, O; Grune, T

    1999-04-01

    Adaptation to oxidative stress is an improved ability to resist the damaging effects of reactive oxygen species, resulting from pre-exposure to a lower dose. Changes in uric acid and glutathione levels during ice-bathing suggest that the intensive voluntary short-term cold exposure of winter swimming produces oxidative stress. We investigated whether the repeated oxidative stress in winter swimmers results in improved antioxidative adaptation. We obtained venous blood samples from winter swimmers and determined important components of the antioxidative defense system in the erythrocytes or blood plasma: reduced and oxidized glutathione (GSH and GSSG), and the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (Cat). The control group consisted of healthy people who had never participated in winter swimming. The baseline concentration of GSH and the activities of erythrocytic SOD and Cat, were higher in winter swimmers. We interpret this as an adaptative response to repeated oxidative stress, and postulate it as a new basic molecular mechanism of increased tolerance to environmental stress.

  13. Precipitation chemistry in and ionic loading to an Alpine Basin, Sierra Nevada

    NASA Astrophysics Data System (ADS)

    Williams, Mark W.; Melack, John M.

    1991-07-01

    Wet deposition of solutes to an alpine catchment in the southern Sierra Nevada was measured from October 1984 through March 1988. Rainfall had a volume-weighted pH of 4.9, and snowfall had a volume-weighted pH of 5.3. Acetic and formic acids were important components of all wet deposition, contributing 25-30% of the measured anions in snowfall and, through analysis of charge balance deficits, the same percentage in rainfall. The NO3- to SO42- equivalent ratio for all wet deposition was 1.16. Ammonium concentration was tenfold greater than H+ in rainfall; ammonium nitrate and ammonium sulfate appear to be the principal nitrate and sulfate containing aerosols in wet deposition. Snowmelt runoff (1985 and 1986) or snowpack runoff plus rainfall during the period of snowpack runoff (1987) supplied 90% of the annual solute flux from wet deposition to the catchment. The amount of snow water equivalence (mm m-2) and H+, SO42-, and Cl- (eq m-2) in cumulative snowfall measured on snowboards was similar to the accumulated deposition of these parameters measured in snowpils at midwinter and during maximum snow accumulation periods, while about 20% of the NO3- in snowfall was not stored in the winter snowpack. Dry deposition was therefore not an important contributor of H+, NO3-, and SO42- to the winter snowpack. The source of the ions in snowfall was air masses that originated over the Pacific Ocean, while low Cl- and Na+ relative to NO3- and NH4+ in rainfall indicate that local urban and agricultural areas were the major source of the ions in rainfall.

  14. How to Have a Healthy Winter | Poster

    Cancer.gov

    Without a doubt, winter is here. Between the icy weather and the recent hustle and bustle of the holidays, everyone is at an increased risk of getting sick. With that in mind, Occupational Health Services has a few simple tips for staying healthy this winter.

  15. 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.

  16. Warm winter, thin ice?

    NASA Astrophysics Data System (ADS)

    Stroeve, Julienne C.; Schroder, David; Tsamados, Michel; Feltham, Daniel

    2018-05-01

    Winter 2016/2017 saw record warmth over the Arctic Ocean, leading to the least amount of freezing degree days north of 70° N since at least 1979. The impact of this warmth was evaluated using model simulations from the Los Alamos sea ice model (CICE) and CryoSat-2 thickness estimates from three different data providers. While CICE simulations show a broad region of anomalously thin ice in April 2017 relative to the 2011-2017 mean, analysis of three CryoSat-2 products show more limited regions with thin ice and do not always agree with each other, both in magnitude and direction of thickness anomalies. CICE is further used to diagnose feedback processes driving the observed anomalies, showing 11-13 cm reduced thermodynamic ice growth over the Arctic domain used in this study compared to the 2011-2017 mean, and dynamical contributions of +1 to +4 cm. Finally, CICE model simulations from 1985 to 2017 indicate the negative feedback relationship between ice growth and winter air temperatures may be starting to weaken, showing decreased winter ice growth since 2012, as winter air temperatures have increased and the freeze-up has been further delayed.

  17. How Winter Time Atmospheric Stability Influences PM2.5 Concentration in Different Complex Terrains; Beijing in China vs Fairbanks in Alaska

    NASA Astrophysics Data System (ADS)

    Karandana Gamalathge, T. D.; Green, M.

    2017-12-01

    Consequences of air pollution is known to majority of the global population. Small particles or aerosols play a significant role in global climate change, and increasing the number of people suffer from poor health. Specially during winter seasons, people live in valleys or close to mountains experience hazy conditions and severe health problems. As a result, aerosol related research works have gained more attention over the last couple of decades. We considered PM2.5-particulate matter less than 2.5 µm of aerodynamic diameter, to see how PM2.5 varies with different atmospheric conditions during winter seasons over two different regions of the world. We selected five winter seasons from November to February from 2011 to 2015 both in Beijing and in Fairbanks. Both locations can be considered as complex terrains, as those regions are surrounded by or close to mountains. Using University of Wyoming's sounding data, we calculated a parameter called Heat Deficit (HD). Higher HD is associated with less turbulence, thus high PM2.5 concentration. On the other hand, low HD is associated with high turbulence, thus low PM2.5 concentration. So, we considered HD as a measure of stability in the region of interest. Despite geographical differences, Fairbanks was covered by snow every day over the study period while Beijing had almost no snow cover. Analysis was done in two ways, with and without paying attention to precipitation. HD was also evaluated with different levels of PM2.5, set up to multiples of average PM2.5 concentration. This was done to check whether HD correlates well with a particular range of PM2.5. A day of precipitation for Fairbanks was considered to be when the daily snowfall >1 inch, while for Beijing when any type of daily precipitation >0.1 inch. Precipitation for Beijing was rare and only 9 days were met even with the 0.1 inch criteria while Fairbanks had 61 days of exceeding the 1 inch criteria. Results revealed that precipitation doesn't impact the

  18. 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

  19. Winter Climate Limits Subantarctic Low Forest Growth and Establishment

    PubMed Central

    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

  20. 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

    2016-05-06

    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.

  1. Satellite Sees Remaining Northeast Snowfall, Connecticut Still Recovering

    NASA Image and Video Library

    2017-12-08

    Last weekend's late October snow may have melted in Maryland, Delaware, parts of Pennsylvania and New Jersey, but residents in north central Connecticut are still dealing with the effects of the storm. According to Connecticut Light and Power, 430,868 residents were still without power today, Nov. 3, 2011. For estimated restoration times, visit their website at: www.cl-p.com/stormcenter/estimates/. A late October snowstorm from a Nor'easter blanketed the eastern U.S. from West Virginia to Maine and broke records the weekend before Halloween Monday. NASA's Aqua satellite flew over the region on October 30 after the snow was ending in New England and captured the ghostly blanket of white. When NASA's Aqua satellite passed over the northeastern U.S. on November 2, 2011 at 2:00 p.m. EDT, the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument captured a detailed image of the remaining snowfall. Snow still covers the ground in western and central Connecticut, southeastern New York, western and central Massachusetts, and parts of Vermont, New Hampshire and Maine. Over the Atlantic, cirrocumulus clouds create a diagonal border. The image was created at NASA's Goddard Space Flight Center in Greenbelt, Md. Image Credit: NASA Goddard MODIS Rapid Response Team; Caption: NASA Goddard, Rob Gutro NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  2. 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

  3. 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 Winter...

  4. Winter to winter recurrence of atmospheric circulation anomalies over East Asia and its impact on winter surface air temperature anomalies

    PubMed Central

    2017-01-01

    The persistence of atmospheric circulation anomalies over East Asia shows a winter to winter recurrence (WTWR) phenomenon. Seasonal variations in sea level pressure anomalies and surface wind anomalies display significantly different characteristics between WTWR and non-WTWR years. The WTWR years are characterized by the recurrence of both a strong (weak) anomalous Siberian High and an East Asian winter monsoon over two successive winters without persistence through the intervening summer. However, anomalies during the non-WTWR years have the opposite sign between the current and ensuing winters. The WTWR of circulation anomalies contributes to that of surface air temperature anomalies (SATAs), which is useful information for improving seasonal and interannual climate predictions over East Asia and China. In the positive (negative) WTWR years, SATAs are cooler (warmer) over East Asia in two successive winters, but the signs of the SATAs are opposite in the preceding and subsequent winters during the non-WTWR years. PMID:28178351

  5. Winter to winter recurrence of atmospheric circulation anomalies over East Asia and its impact on winter surface air temperature anomalies.

    PubMed

    Zhao, Xia; Yang, Guang

    2017-01-01

    The persistence of atmospheric circulation anomalies over East Asia shows a winter to winter recurrence (WTWR) phenomenon. Seasonal variations in sea level pressure anomalies and surface wind anomalies display significantly different characteristics between WTWR and non-WTWR years. The WTWR years are characterized by the recurrence of both a strong (weak) anomalous Siberian High and an East Asian winter monsoon over two successive winters without persistence through the intervening summer. However, anomalies during the non-WTWR years have the opposite sign between the current and ensuing winters. The WTWR of circulation anomalies contributes to that of surface air temperature anomalies (SATAs), which is useful information for improving seasonal and interannual climate predictions over East Asia and China. In the positive (negative) WTWR years, SATAs are cooler (warmer) over East Asia in two successive winters, but the signs of the SATAs are opposite in the preceding and subsequent winters during the non-WTWR years.

  6. The role of declining summer sea ice extent in increasing Arctic winter precipitation

    NASA Astrophysics Data System (ADS)

    Hamman, J.; Roberts, A.; Cassano, J. J.; Nijssen, B.

    2016-12-01

    In the past three decades, the Arctic has experienced large declines in summer sea ice cover, permafrost extent, and spring snow cover, and increases in winter precipitation. This study explores the relationship between declining Arctic sea ice extent (IE) and winter precipitation (WP) across the Arctic land masses. The first part of this presentation presents the observed relationship between IE and WP. Using satellite estimates of IE and WP data based on a combination of in-situ observations and global reanalyses, we show that WP is negatively correlated with summer IE and that this relationship is strongest before the year 2000. After 2000, around the time IE minima began to decline most rapidly, the relationship between IE and WP degenerates. This indicates that other processes are driving changes in IE and WP. We hypothesize that positive anomalies in poleward moisture transport have historically driven anomalously low IE and high WP, and that since the significant decline in IE, moisture divergence from the central Arctic has been a larger contributor to WP over land. To better understand the physical mechanisms driving the observed changes in the Arctic climate system and the sensitivity of the Arctic climate system to declining sea ice, we have used the fully-coupled Regional Arctic System Model (RASM) to simulate two distinct sea ice climates. The first climate represents normal IE, while the second includes reduced summer IE. The second portion of this presentation analyzes these two RASM simulations, in conjunction with our observation-based analysis, to understand the coupled relationship between poleward moisture transport, IE, evaporation from the Arctic Ocean, and precipitation. We will present the RASM-simulated Arctic water budget and demonstrate the role of IE in driving WP anomalies. Finally, a spatial correlation analysis identifies characteristic patterns in IE, ocean evaporation, and polar cap convergence that contribute to anomalies in WP.

  7. 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.

  8. The influence of winter swimming on the rheological properties of blood.

    PubMed

    Teległów, Aneta; Dąbrowski, Zbigniew; Marchewka, Anna; Tyka, Aleksander; Krawczyk, Marcin; Głodzik, Jacek; Szyguła, Zbigniew; Mleczko, Edward; Bilski, Jan; Tyka, Anna; Tabarowski, Zbigniew; Czepiel, Jacek; Filar-Mierzwa, Katarzyna

    2014-01-01

    The aim of this study was to analyze the changes in blood rheology resulting from regular winter swimming. The study was carried out on 12 male winter swimmers. Venous blood for morphological, biochemical and rheological analysis was sampled twice from each winter swimmer - at the beginning of the season and after its completion. There were no significant changes detected in the median values of most blood morphological parameters. The only exception pertained to MCHC which was significantly lower after the season. Winter swimming entailed significant decrease in median elongation index values at shear stress levels of 0.30 Pa and 0.58 Pa, and significant increase in median values of this parameter at shear stress levels ≥1.13 Pa. No significant changes were observed in winter swimmers' median values of aggregation indices and plasma viscosity. The median level of glucose was lower post winter swimming in comparison to the pre-seasonal values. In contrast, one season of winter swimming did not influence swimmers' median value of fibrinogen concentration. In summary, this study revealed positive effects of winter swimming on the rheological properties of blood, manifested by an increase in erythrocyte deformability without accompanying changes in erythrocyte aggregation.

  9. Accelerated increase in the Arctic tropospheric warming events surpassing stratospheric warming events during winter: Accelerated Increase in Arctic Warming

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

    Wang, S. -Y. Simon; Lin, Yen-Heng; Lee, Ming-Ying

    In January 2016, a robust reversal of the Arctic Oscillation (AO) took place associated with a rapid tropospheric warming in the Arctic region; this was followed by the occurrence of a classic sudden stratospheric warming in March-April. The succession of these two distinct Arctic warming events provides a stimulating opportunity to examine their characteristics in terms of similarities and differences. Historical cases of these two types of Arctic warming were identified and validated based upon tropical linkages with the Madden-Julian Oscillation and El Niño as well as those documented in previous studies. Our results indicate a recent and accelerated increasemore » in the tropospheric warming type versus a flat trend in stratospheric warming type. Given that tropospheric warming events occur twice as fast than the stratospheric warming type, the noted increase in the former implies further intensification in midlatitude winter weather extremes similar to those experienced in early 2016. Forced simulations with an atmospheric general circulation model suggest that the reduced Arctic sea ice contributes to the observed increase in the tropospheric warming events and associated impact on the anomalously cold Siberia.« less

  10. Climate impacts on bird and plant communities from altered animal-plant interactions

    USGS Publications Warehouse

    Martin, Thomas E.; Maron, John L.

    2012-01-01

    The contribution of climate change to declining populations of organisms remains a question of outstanding concern. Much attention to declining populations has focused on how changing climate drives phenological mismatches between animals and their food. Effects of climate on plant communities may provide an alternative, but particularly powerful, influence on animal populations because plants provide their habitats. Here, we show that abundances of deciduous trees and associated songbirds have declined with decreasing snowfall over 22 years of study in montane Arizona, USA. We experimentally tested the hypothesis that declining snowfall indirectly influences plants and associated birds by allowing greater over-winter herbivory by elk (Cervus canadensis). We excluded elk from one of two paired snowmelt drainages (10 ha per drainage), and replicated this paired experiment across three distant canyons. Over six years, we reversed multi-decade declines in plant and bird populations by experimentally inhibiting heavy winter herbivory associated with declining snowfall. Moreover, predation rates on songbird nests decreased in exclosures, despite higher abundances of nest predators, demonstrating the over-riding importance of habitat quality to avian recruitment. Thus, our results suggest that climate impacts on plant–animal interactions can have forceful ramifying effects on plants, birds, and ecological interactions.

  11. Climate impacts on bird and plant communities from altered animal-plant interactions

    NASA Astrophysics Data System (ADS)

    Martin, Thomas E.; Maron, John L.

    2012-03-01

    The contribution of climate change to declining populations of organisms remains a question of outstanding concern. Much attention to declining populations has focused on how changing climate drives phenological mismatches between animals and their food. Effects of climate on plant communities may provide an alternative, but particularly powerful, influence on animal populations because plants provide their habitats. Here, we show that abundances of deciduous trees and associated songbirds have declined with decreasing snowfall over 22 years of study in montane Arizona, USA. We experimentally tested the hypothesis that declining snowfall indirectly influences plants and associated birds by allowing greater over-winter herbivory by elk (Cervus canadensis). We excluded elk from one of two paired snowmelt drainages (10 ha per drainage), and replicated this paired experiment across three distant canyons. Over six years, we reversed multi-decade declines in plant and bird populations by experimentally inhibiting heavy winter herbivory associated with declining snowfall. Moreover, predation rates on songbird nests decreased in exclosures, despite higher abundances of nest predators, demonstrating the over-riding importance of habitat quality to avian recruitment. Thus, our results suggest that climate impacts on plant-animal interactions can have forceful ramifying effects on plants, birds, and ecological interactions.

  12. Does winter desiccation account for seasonal increases in supercooling capacity of Norway spruce bud primordia?

    PubMed Central

    Koch, Sabrina; Munkler, Caspar; Resnyak, Anna; Buchner, Othmar; Oberhammer, Marian; Neuner, Gilbert

    2018-01-01

    Abstract Bud primordia of Picea abies (L.) H. Karst. remain ice free at subzero temperatures by supercooling. Once ice forms inside the primordium, it is immediately injured. Supercooling capacity increases seasonally from ~−5 °C to as much as −50 °C by currently unknown mechanisms. Among other prerequisites, dehydration of tissues over the winter months has been considered to play a key role in freezing tolerance. In this regard, the water content of bud primordia may be crucial, especially in reference to supercooling. In order to assess the role of dehydration in supercooling capacity, seasonal changes in supercooling capacity and the water potential of bud primordia of Picea abies (L.) H. Karst were measured at two sites that differed by 1298 m in elevation, after artificial frost hardening and dehardening treatments and after controlled bench drying. The extent of supercooling of bud primordia varied from −7 °C in summer to −24.6 °C in winter, a difference of 17.6 –19.3 K. Total actual water potential (Ψtact) of bud primordia was −2 MPa in summer and decreased to a mean of −3.8 MPa in midwinter. The decline involved dehydration, and to a lesser extent, osmoregulation. At decreased Ψtact values (<3.0 MPa), supercooling capacity significantly increased <−19.5 °C, however, the correlation between actual water potential and supercooling capacity was poor. Frost-hardening treatments increased the supercooling capacity of bud primordia (−0.6 K day−1) and lowered Ψtact (−0.2 MPa day−1). Frost-dehardening treatments reduced supercooling capacity (+1.1 K day−1), and at the same time, increased Ψtact (+0.3 MPa day−1). In contrast, artificial drying of bud primordia in the range observed seasonally (−2.0 MPa) had no effect on supercooling capacity. These results suggest that there is no causal relationship between desiccation and the supercooling capacity of bud primordia in P. abies, but rather it involves other compounds within

  13. 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

  14. Surgical risks associated with winter sport tourism.

    PubMed

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

    2015-01-01

    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. 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. 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). Surgical outcomes are not compromised during winter in French mountain areas despite a substantial influx of major emergencies.

  15. Winter Ecology.

    ERIC Educational Resources Information Center

    Birkeland, Karl W.; Halfpenny, James C.

    1987-01-01

    Discusses some of the ecological variables involved with plant and animal survival during the winter months. Addresses the effects of changing climatic conditions on habitats, foot-loading indexes, and the overall concept of adaptation. Provides some simple teaching activities dealing with winter survival. (TW)

  16. “Exploring Effects of Climate Change on Northern Plains American Indian Health”

    PubMed Central

    Redsteer, Margaret Hiza; Eggers, Margaret J.

    2013-01-01

    American Indians have unique vulnerabilities to the impacts of climate change because of the links among ecosystems, cultural practices, and public health, but also as a result of limited resources available to address infrastructure needs. On the Crow Reservation in south-central Montana, a Northern Plains American Indian Reservation, there are community concerns about the consequences of climate change impacts for community health and local ecosystems. Observations made by Tribal Elders about decreasing annual snowfall and milder winter temperatures over the 20th century initiated an investigation of local climate and hydrologic data by the Tribal College. The resulting analysis of meteorological data confirmed the decline in annual snowfall and an increase in frost free days. In addition, the data show a shift in precipitation from winter to early spring and a significant increase in days exceeding 90° F (32° C). Streamflow data show a long-term trend of declining discharge. Elders noted that the changes are affecting fish distribution within local streams and plant species which provide subsistence foods. Concerns about warmer summer temperatures also include heat exposure during outdoor ceremonies that involve days of fasting without food or water. Additional community concerns about the effects of climate change include increasing flood frequency and fire severity, as well as declining water quality. The authors call for local research to understand and document current effects and project future impacts as a basis for planning adaptive strategies. PMID:24265512

  17. Comparison of Selected Morphological, Rheological and Biochemical Parameters of Winter Swimmers' Blood at the End of One Winter Swimming Season and at the Beginning of Another.

    PubMed

    Teległów, Aneta; Marchewka, Jakub; Tabarowski, Zbigniew; Rembiasz, Konrad; Głodzik, Jacek; Scisłowska-Czarnecka, Anna

    2015-01-01

    The aim of the study was to examine potential differences in the morphological, rheological and biochemical blood parameters of winter swimmers who remained physically active during the period between the end of one winter swimming season and the beginning of another. The study included a group of healthy winter swimmers (n = 17, all between 30 and 60 years of age). Six months following the end of winter season, the levels of mean corpuscular hemoglobin concentration and mean corpuscular hemoglobin turned out to be significantly higher, while erythrocyte count and hematocrit level significantly lower than at the baseline. Moreover, the break in winter swimming was reflected by a significant increase in median erythrocyte elongation index at all shear stress levels ≥ 1.13 Pa. The only significant changes in biochemical parameters of the blood pertained to an increase in the concentration of transferrin and to a decrease in the total protein, albumin and beta-1 globulin concentrations. Seasonal effort of winter swimmers between the end of one winter swimming season and the beginning of another has a positive influence on morphological, rheological and biochemical blood parameters.

  18. 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.

  19. 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…

  20. Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) Observations of Polar Winter Conditions in 2009; Comparisons with Years 2002-2008

    DTIC Science & Technology

    2011-02-03

    focused upon the tropospheric forcing, for example the role of blocking systems (large-scale, quasi-stationary, high-pressure systems that may steer...disruptions of the stratosphere may in turn perturb the troposphere and even affect surface weather. In early February 2009, London received heavy snowfall...global measurements from twelve SSW periods, found cooling in the equatorial lower stratosphere and upper troposphere that is associated with increased

  1. Barriers to wheelchair use in the winter.

    PubMed

    Ripat, Jacquie D; Brown, Cara L; Ethans, Karen D

    2015-06-01

    To test the hypothesis that challenges to community participation posed by winter weather are greater for individuals who use scooters, manual and power wheelchairs (wheeled mobility devices [WMDs]) than for the general ambulatory population, and to determine what WMD users identify as the most salient environmental barriers to community participation during the winter. Cross-sectional survey organized around 5 environmental domains: technological, natural, physical, social/attitudinal, and policy. Urban community in Canada. Convenience sample of WMD users or their proxy (N=99). Not applicable. Not applicable. Forty-two percent identified reduced outing frequency in winter months, associated with increased age (χ(3)=6.4, P=.04), lack of access to family/friends for transportation (χ(2)=8.1, P=.04), and primary type of WMD used in the winter (scooter χ(2)=8.8, P=.003). Most reported tires/casters becoming stuck in the snow (95%) or slipping on the ice (91%), difficulty ascending inclines/ramps (92%), and cold hands while using controls or pushing rims (85%); fewer identified frozen wheelchair/scooter batteries, seat cushions/backrests, or electronics. Sidewalks/roads were reported to be problematic by 99%. Eighty percent reported needing additional help in the winter. Limited community access in winter led to a sense of loneliness/isolation, and fear/anxiety related to safety. Respondents identified policies that limited participation during winter. People who use WMDs decrease their community participation in cold weather because of multiple environmental barriers. Clinicians, researchers, and policymakers can take a multidimensional approach to mitigate these barriers in order to enhance community participation by WMD users in winter. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  2. Measurements of sea ice mass redistribution during ice deformation event in Arctic winter

    NASA Astrophysics Data System (ADS)

    Itkin, P.; Spreen, G.; King, J.; Rösel, A.; Skourup, H.; Munk Hvidegaard, S.; Wilkinson, J.; Oikkonen, A.; Granskog, M. A.; Gerland, S.

    2016-12-01

    Sea-ice growth during high winter is governed by ice dynamics. The highest growth rates are found in leads that open under divergent conditions, where exposure to the cold atmosphere promotes thermodynamic growth. Additionally ice thickens dynamically, where convergence causes rafting and ridging. We present a local study of sea-ice growth and mass redistribution between two consecutive airborne measurements, on 19 and 24 April 2015, during the N-ICE2015 expedition in the area north of Svalbard. Between the two overflights an ice deformation event was observed. Airborne laser scanner (ALS) measurements revisited the same sea-ice area of approximately 3x3 km. By identifying the sea surface within the ALS measurements as a reference the sea ice plus snow freeboard was obtained with a spatial resolution of 5 m. By assuming isostatic equilibrium of level floes, the freeboard heights can be converted to ice thickness. The snow depth is estimated from in-situ measurements. Sea ice thickness measurements were made in the same area as the ALS measurements by electromagnetic sounding from a helicopter (HEM), and with a ground-based device (EM31), which allows for cross-validation of the sea-ice thickness estimated from all 3 procedures. Comparison of the ALS snow freeboard distributions between the first and second overflight shows a decrease in the thin ice classes and an increase of the thick ice classes. While there was no observable snowfall and a very low sea-ice growth of older level ice during this period, an autonomous buoy array deployed in the surroundings of the area measured by the ALS shows first divergence followed by convergence associated with shear. To quantify and link the sea ice deformation with the associated sea-ice thickness change and mass redistribution we identify over 100 virtual buoys in the ALS data from both overflights. We triangulate the area between the buoys and calculate the strain rates and freeboard change for each individual triangle

  3. Factors Contributing to Extremely Wet Winters in California

    NASA Astrophysics Data System (ADS)

    Jong, B. T.; Ting, M.; Seager, R.

    2015-12-01

    As California continues to battle the severe drought conditions, it becomes increasingly important to understand the atmospheric and oceanic conditions that may possible break this ongoing drought. Is a strong El Niño, such as the 2015/16 event, enough to break the drought? We examine in this study the possible factors that lead to extremely wet winters (the wettest 15%) in both Northern and Southern CA. The relationships between CA winter precipitation and sea surface temperature conditions in the Pacific, as well as atmospheric circulation are determined by using observational and reanalysis data from 1901 to 2010. One of the key features of the atmospheric circulation is the location of the low pressure anomaly, whether caused by El Niño or other factors. If the anomaly locates right off the US west coast, CA tends to be wet, and vice versa. Furthermore, the duration of the circulation anomaly seems to be crucial. During wet El Niño winters, the peak of the circulation anomaly is in the late winter, whereas, during non-wet El Niño winters, the peak of the anomaly is in the early winter. Thus, an El Niño that can last to late winter is more likely to cause an extremely wet winter in the state. The intensity of El Niño is another critical factor. In the wettest tercile late winter, a strong El Niño can bring about 200% of climatological precipitation to CA, while a weak El Niño can bring only less than 150% of climatology. In combination, only a strong El Niño that can last to late winter may make extremely wet winters very likely in CA. To explore the other factors, composites of circulation anomaly during wet & non-El Niño winters were also analyzed. The results show that a zonally propagating wave train, originating from western North Pacific, contributes to low pressure center and wet winter conditions in the state. Thus, coastal low pressure anomaly is a consistent feature for an extremely wet winters in California, but the origin of forcing can

  4. 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.

  5. Greater mass increases annual survival of Prothonotary Warblers wintering in northeastern Costa Rica

    Treesearch

    Jared D. Wolfe; Matthew D. Johnson; C. John Ralph

    2013-01-01

    Estimates of survival of nearctic-neotropic migrants have broadened our understanding of life-history variation across taxa and latitudes. Despite the importance of assessing migrants' survival through all phases of their life-cycle, data from their tropical winter ranges are few. In this study we used 14 years of data on captured birds to quantify the influence...

  6. Seasonal change in precipitation, snowpack, snowmelt, soil water and streamwater chemistry, northern Michigan

    USGS Publications Warehouse

    Stottlemyer, R.; Toczydlowski, D.

    1999-01-01

    We have studied weekly precipitation, snowpack, snowmelt, soil water and streamwater chemistry throughout winter for over a decade in a small (176 ha) northern Michigan watershed with high snowfall and vegetated by 60 to 80 year-old northern hardwoods. In this paper, we examine physical, chemical, and biological processes responsible for observed seasonal change in streamwater chemistry based upon intensive study during winter 1996-1997. The objective was to define the contributions made to winter and spring streamwater chemical concentration and flux by processes as snowmelt, over-winter forest floor and surface soil mineralization, immobilization, and exchange, and subsurface flowpath. The forest floor and soil were unfrozen beneath the snowpack which permitted most snowmelt to enter. Over-winter soil mineralization and other biological processes maintain shallow subsurface ion and dissolved organic carbon (DOC) reservoirs. Small, but steady, snowmelt throughout winter removed readily mobilized soil NO3- which resulted in high over-winter streamwater concentrations but little flux. Winter soil water levels and flowpaths were generally deep which increased soil water and streamwater base cation (C(B)), HCO3-, and Si concentrations. Spring snowmelt increased soil water levels and removal of ions and DOC from the biologically active forest floor and shallow soils. The snowpack solute content was a minor component in determining streamwater ion concentration or flux during and following peak snowmelt. Exchangeable ions, weakly adsorbed anions, and DOC in the forest floor and surface soils dominated the chemical concentration and flux in soil water and streamwater. Following peak snowmelt, soil microbial immobilization and rapidly increased plant uptake of limiting nutrients removed nearly all available nitrogen from soil water and streamwater. During the growing season high evapotranspiration increased subsurface flowpath depth which in turn removed weathering

  7. Climatic warming increases winter wheat yield but reduces grain nitrogen concentration in east China.

    PubMed

    Tian, Yunlu; Zheng, Chengyan; Chen, Jin; Chen, Changqing; Deng, Aixing; Song, Zhenwei; Zhang, Baoming; Zhang, Weijian

    2014-01-01

    Climatic warming is often predicted to reduce wheat yield and grain quality in China. However, direct evidence is still lacking. We conducted a three-year experiment with a Free Air Temperature Increase (FATI) facility to examine the responses of winter wheat growth and plant N accumulation to a moderate temperature increase of 1.5°C predicted to prevail by 2050 in East China. Three warming treatments (AW: all-day warming; DW: daytime warming; NW: nighttime warming) were applied for an entire growth period. Consistent warming effects on wheat plant were recorded across the experimental years. An increase of ca. 1.5°C in daily, daytime and nighttime mean temperatures shortened the length of pre-anthesis period averagely by 12.7, 8.3 and 10.7 d (P<0.05), respectively, but had no significant impact on the length of the post-anthesis period. Warming did not significantly alter the aboveground biomass production, but the grain yield was 16.3, 18.1 and 19.6% (P<0.05) higher in the AW, DW and NW plots than the non-warmed plot, respectively. Warming also significantly increased plant N uptake and total biomass N accumulation. However, warming significantly reduced grain N concentrations while increased N concentrations in the leaves and stems. Together, our results demonstrate differential impacts of warming on the depositions of grain starch and protein, highlighting the needs to further understand the mechanisms that underlie warming impacts on plant C and N metabolism in wheat.

  8. Accelerated Increase in the Arctic Tropospheric Warming Events Surpassing StratosphericWarming Events During Winter

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

    Wang, Simon; Lin, Yen-Heng; Lee, Ming-Ying

    2017-04-22

    In January 2016, a robust reversal of the Arctic Oscillation (AO) took place associated with a rapid tropospheric warming in the Arctic region; this was followed by the occurrence of a classic sudden stratospheric warming in March-April. The succession of these two distinct Arctic warming events provides a stimulating opportunity to examine their characteristics in terms of similarities and differences. Historical cases of these two types of Arctic warming were identified and validated based upon tropical linkages with the Madden-Julian Oscillation and El Niño as well as those documented in previous studies. Our results indicate a recent and accelerated increasemore » in the tropospheric warming type versus a flat trend in stratospheric warming type. Given that tropospheric warming events occur twice as fast than the stratospheric warming type, the noted increase in the former implies further intensification in midlatitude winter weather extremes similar to those experienced in early 2016. Forced simulations with an atmospheric general circulation model suggest that the reduced Arctic sea ice contributes to the observed increase in the tropospheric warming events and associated impact on the anomalously cold Siberia.« less

  9. 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.

  10. 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. ...

  11. Record-breaking Ozone Loss during Arctic Winter 2010/2011: Comparison with Arctic Winter 1996/1997

    NASA Astrophysics Data System (ADS)

    Godin Beekmann, S.; Kuttipurath, J.; Lefèvre, F.; Santee, M. L.; Froidevaux, L.

    2011-12-01

    Polar processing and chemical ozone loss is analysed during the Arctic winter/spring 2010/2011. The analyses with temperatures and potential vorticity (PV) data show a prolonged vortex from early December through mid-April. The PV maps illustrate strong vortex persistence in the lower stratosphere between 450 and 675 K, showing similar evolution with time. The minimum temperatures extracted from ECMWF data at 40-90°N show values below 195 K for a record period of first week of December through second week of April, indicating the longest period of colder temperatures for 17 years. At 10 hPa, there was a warming of about 10 K at 60°N and 40 K at 90°N around mid-January. The heat flux also showed high values in line with the increase in temperatures, of about 425 m K/s at 60°N at the same pressure level. However, the westerlies were strong (e.g. 35-45 m/s at 60°N) enough to keep the vortex intact until mid-April. Because of the cold temperatures in late winter and early spring, large areas of Polar Stratospheric Clouds (PSC) were found in the 400-600 K isentropic level range. Though the maximum values of PSCs area are smaller compared to other cold winters such as 2005, the extended period of presence of PSCs during this winter was exceptional, especially in late February-mid-March, in agreement with the cold temperatures during the period. Ozone loss analyses with high resolution Mimosa-Chim chemical transport model simulations show that the loss started by early January, and was about 0.5 ppmv in late January. The loss progressed slowly to 1 ppmv by the end of February, and then intensified by early March. The ozone depletion estimated by the passive method finds a maximum value of about 2-2.3 ppmv by the end of March-early April in the 450-550K range inside the vortex, which coincides with the areas of PSCs and high chlorine activation. This is the largest loss ever estimated with this model for any Arctic winter. It is consistent with the unprecedented

  12. Marrow fat deposition and skeletal growth in caribou calves

    USGS Publications Warehouse

    Adams, Layne G.

    2003-01-01

    I evaluated rates of marrow fat deposition and skeletal growth of caribou (Rangifer tarandus granti) calves through 20 days of age at Denali National Park, Alaska, USA. Both were negatively correlated with late winter snowfall, indicating the prolonged effects of maternal undernutrition following severe winters. Using regression analyses, I found that the rates of marrow fat deposition and hindfoot growth during the 20 days following birth declined 46% and 68%, respectively, over the range of winter severity during this study. These measures of development may indicate a broader array of effects of maternal undernutrition, influencing the vulnerability of caribou calves to predation.

  13. Deciphering the contrasting climatic trends between the central Himalaya and Karakoram with 36 years of WRF simulations

    NASA Astrophysics Data System (ADS)

    Norris, Jesse; Carvalho, Leila M. V.; Jones, Charles; Cannon, Forest

    2018-02-01

    Glaciers over the central Himalaya have retreated at particularly rapid rates in recent decades, while glacier mass in the Karakoram appears stable. To address the meteorological factors associated with this contrast, 36 years of Climate Forecast System Reanalyses (CFSR) are dynamically downscaled from 1979 to 2015 with the Weather Research and Forecasting (WRF) model over High Mountain Asia at convection permitting grid spacing (6.7 km). In all seasons, CFSR shows an anti-cyclonic warming trend over the majority of High Mountain Asia, but distinctive differences are observed between the central Himalaya and Karakoram in winter and summer. In winter and summer, the central Himalaya has been under the influence of an anti-cyclonic trend, which in summer the downscaling shows has reduced cloud cover, leading to significant warming and reduced snowfall in recent years. Contrastingly, the Karakoram has been near the boundary between large-scale cyclonic and anti-cyclonic trends and has not experienced significant snowfall or temperature changes in winter or summer, despite significant trends in summer of increasing cloud cover and decreasing shortwave radiation. This downscaling does not identify any trends over glaciers in closer neighboring regions to the Karakoram (e.g., Hindu Kush and the western Himalaya) where glaciers have retreated as over the central Himalaya, indicating that there are other factors driving glacier mass balance that this downscaling is unable to capture. While this study does not fully explain the Karakoram anomaly, the identified trends detail important meteorological contributions to the observed differences between central Himalaya and Karakoram glacier evolution in recent decades.

  14. Impact of warm winters on microbial growth

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    Growth of soil bacteria has an asymmetrical response to higher temperature with a gradual increase with increasing temperatures until an optimum after which a steep decline occurs. In laboratory studies it has been shown that by exposing a soil bacterial community to a temperature above the community's optimum temperature for two months, the bacterial community grows warm-adapted, and the optimum temperature of bacterial growth shifts towards higher temperatures. This result suggests a change in the intrinsic temperature dependence of bacterial growth, as temperature influenced the bacterial growth even though all other factors were kept constant. An intrinsic temperature dependence could be explained by either a change in the bacterial community composition, exchanging less tolerant bacteria towards more tolerant ones, or it could be due to adaptation within the bacteria present. No matter what the shift in temperature tolerance is due to, the shift could have ecosystem scale implications, as winters in northern Europe are getting warmer. To address the question of how microbes and plants are affected by warmer winters, a winter-warming experiment was established in a South Swedish grassland. Results suggest a positive response in microbial growth rate in plots where winter soil temperatures were around 6 °C above ambient. Both bacterial and fungal growth (leucine incorporation, and acetate into ergosterol incorporation, respectively) appeared stimulated, and there are two candidate explanations for these results. Either (i) warming directly influence microbial communities by modulating their temperature adaptation, or (ii) warming indirectly affected the microbial communities via temperature induced changes in bacterial growth conditions. The first explanation is in accordance with what has been shown in laboratory conditions (explained above), where the differences in the intrinsic temperature relationships were examined. To test this explanation the

  15. Winter visitor use planning in Yellowstone and Grand Teton National Parks

    Treesearch

    John A. Sacklin; Kristin L. Legg; M. Sarah Creachbaum; Clifford L. Hawkes; George Helfrich

    2000-01-01

    Winter use in Yellowstone and Grand Teton National Parks increased dramatically in the 1980s and early 1990s. That increase and the emphasis on snowmobiles as the primary mode of transportation brought into focus a host of winter-related issues, including air pollution, unwanted sound, wildlife impacts and the adequacy of agency budgets, staff and infrastructure to...

  16. 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.

  17. Research on spatial distribution of photosynthetic characteristics of Winter Wheat

    NASA Astrophysics Data System (ADS)

    Yan, Q. Q.; Zhou, Q. Y.; Zhang, B. Z.; Han, X.; Han, N. N.; Li, S. M.

    2018-03-01

    In order to explore the spatial distribution of photosynthetic characteristics of winter wheat leaf, the photosynthetic rate on different parts of leaf (leaf base-leaf middle-leaf apex) and that on each canopy (top layer-middle layer-bottom layer) leaf during the whole growth period of winter wheat were measured. The variation of photosynthetic rate with PAR and the spatial distribution of winter wheat leaf during the whole growth periods were analysed. The results showed that the photosynthetic rate of different parts of winter wheat increased with the increase of PAR, which was showed as leaf base>leaf middle>leaf apex. In the same growth period, photosynthetic rate in different parts of the tablet was showed as leaf middle>leaf base>leaf apex. For the different canopy layer of winter wheat, the photosynthetic rate of the top layer leaf was significantly greater than that of the middle layer and lower layer leaf. The photosynthetic rate of the top layer leaf was the largest in the leaf base position. The photosynthetic rate of leaf of the same canopy layer at different growth stages were showed as tasseling stage >grain filling stage > maturation stage.

  18. Characteristics of Lightning Within Electrified Snowfall Events Using Lightning Mapping Arrays

    NASA Astrophysics Data System (ADS)

    Schultz, Christopher J.; Lang, Timothy J.; Bruning, Eric C.; Calhoun, Kristin M.; Harkema, Sebastian; Curtis, Nathan

    2018-02-01

    This study examined 34 lightning flashes within four separate thundersnow events derived from lightning mapping arrays (LMAs) in northern Alabama, central Oklahoma, and Washington DC. The goals were to characterize the in-cloud component of each lightning flash, as well as the correspondence between the LMA observations and lightning data taken from national lightning networks like the National Lightning Detection Network (NLDN). Individual flashes were examined in detail to highlight several observations within the data set. The study results demonstrated that the structures of these flashes were primarily normal polarity. The mean area encompassed by this set of flashes is 375 km2, with a maximum flash extent of 2,300 km2, a minimum of 3 km2, and a median of 128 km2. An average of 2.29 NLDN flashes were recorded per LMA-derived lightning flash. A maximum of 11 NLDN flashes were recorded in association with a single LMA-derived flash on 10 January 2011. Additionally, seven of the 34 flashes in the study contain zero NLDN-identified flashes. Eleven of the 34 flashes initiated from tall human-made objects (e.g., communication towers). In at least six lightning flashes, the NLDN detected a return stroke from the cloud back to the tower and not the initial upward leader. This study also discusses lightning's interaction with the human-built environment and provides an example of lightning within heavy snowfall observed by Geostationary Operational Environmental Satellite-16's Geostationary Lightning Mapper.

  19. Characteristics of Lightning within Electrified Snowfall Events using Lightning Mapping Arrays.

    PubMed

    Schultz, Christopher J; Lang, Timothy J; Bruning, Eric C; Calhoun, Kristin M; Harkema, Sebastian; Curtis, Nathan

    2018-02-27

    This study examined 34 lightning flashes within four separate thundersnow events derived from lightning mapping arrays (LMAs) in northern Alabama, central Oklahoma, and Washington DC. The goals were to characterize the in-cloud component of each lightning flash, as well as the correspondence between the LMA observations and lightning data taken from national lightning networks like the National Lightning Detection Network (NLDN). Individual flashes were examined in detail to highlight several observations within the dataset. The study results demonstrated that the structures of these flashes were primarily normal polarity. The mean area encompassed by this set of flashes is 375 km 2 , with a maximum flash extent of 2300 km 2 , a minimum of 3 km 2 , and a median of 128 km 2 . An average of 2.29 NLDN flashes were recorded per LMA-derived lightning flash. A maximum of 11 NLDN flashes were recorded in association with a single LMA-derived flash on 10 January 2011. Additionally, seven of the 34 flashes in the study contain zero NLDN identified flashes. Eleven of the 34 flashes initiated from tall human-made objects (e.g., communication towers). In at least six lightning flashes, the NLDN detected a return stroke from the cloud back to the tower and not the initial upward leader. This study also discusses lightning's interaction with the human built environment and provides an example of lightning within heavy snowfall observed by GOES-16's Geostationary Lightning Mapper.

  20. 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.

  1. 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.

  2. Finding Snowmageddon: Detecting and quantifying northeastern U.S. snowstorms in a multi-decadal global climate ensemble

    NASA Astrophysics Data System (ADS)

    Zarzycki, C. M.

    2017-12-01

    The northeastern coast of the United States is particularly vulnerable to impacts from extratropical cyclones during winter months, which produce heavy precipitation, high winds, and coastal flooding. These impacts are amplified by the proximity of major population centers to common storm tracks and include risks to health and welfare, massive transportation disruption, lost spending productivity, power outages, and structural damage. Historically, understanding regional snowfall in climate models has generally centered around seasonal mean climatologies even though major impacts typically occur at the scales of hours to days. To quantify discrete snowstorms at the event level, we describe a new objective detection algorithm for gridded data based on the Regional Snowfall Index (RSI) produced by NOAA's National Centers for Environmental Information. The algorithm uses 6-hourly precipitation to collocate storm-integrated snowfall with population density to produce a distribution of snowstorms with societally relevant impacts. The algorithm is tested on the Community Earth System Model (CESM) Large Ensemble Project (LENS) data. Present day distributions of snowfall events is well-replicated within the ensemble. We discuss classification sensitivities to assumptions made in determining precipitation phase and snow water equivalent. We also explore projected reductions in mid-century and end-of-century snowstorms due to changes in snowfall rates and precipitation phase, as well as highlight potential improvements in storm representation from refined horizontal resolution in model simulations.

  3. Mule deer and elk winter diet as an indicator of habitat competition

    Treesearch

    Michael R. Frisina; Carl L. Wambolt; W. Wyatt Fraas; Glen Guenther

    2008-01-01

    Mule deer (Odocoileus hemionus) populations have gradually declined in recent decades, while elk (Cervus elaphus) have often increased throughout their common ranges. The cause is uncertain and a source of debate. Increasing elk numbers on these ungulate winter ranges may be causing competition for resources. We contrast winter...

  4. 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.

  5. Long Term Decline in Eastern US Winter Temperature Extremes.

    NASA Astrophysics Data System (ADS)

    Trenary, L. L.; DelSole, T. M.; Tippett, M. K.; Doty, B.

    2016-12-01

    States along the US eastern seaboard have experienced successively harsh winter conditions in recent years. This has prompted speculation that climate change is leading to more extreme winter conditions. In this study we quantify changes in the observed winter extremes over the period 1950-2015, by examining year-to-year differences in intensity, frequency and likelihood of daily cold temperature extremes in the north, mid, and south Atlantic states along the US east coast. Analyzing station data for these three regions, we find that while the north and mid-Atlantic regions experienced record-breaking cold temperatures in 2015, there is no long-term increase in the intensity of cold extremes anywhere along the eastern seaboard. Likewise, despite the record number of cold days in these two regions during 2014 and 2015, there is no systematic increase in the frequency of cold extremes. To determine whether the observed changes are natural or human-forced, we repeat our analysis using a suite of climate simulations, with and without external forcing. Generally, model simulations suggest that human-induced forcing does not significantly influence the range of daily winter temperature. Combining this result with the fact that the observed winter temperatures are becoming warmer and less variable, we conclude that the recent intensification of eastern US cold extremes is only temporary.

  6. Unexpected winter phytoplankton blooms in the North Atlantic subpolar gyre

    NASA Astrophysics Data System (ADS)

    Lacour, L.; Ardyna, M.; Stec, K. F.; Claustre, H.; Prieur, L.; Poteau, A.; D'Alcala, M. Ribera; Iudicone, D.

    2017-11-01

    In mid- and high-latitude oceans, winter surface cooling and strong winds drive turbulent mixing that carries phytoplankton to depths of several hundred metres, well below the sunlit layer. This downward mixing, in combination with low solar radiation, drastically limits phytoplankton growth during the winter, especially that of the diatoms and other species that are involved in seeding the spring bloom. Here we present observational evidence for widespread winter phytoplankton blooms in a large part of the North Atlantic subpolar gyre from autonomous profiling floats equipped with biogeochemical sensors. These blooms were triggered by intermittent restratification of the mixed layer when mixed-layer eddies led to a horizontal transport of lighter water over denser layers. Combining a bio-optical index with complementary chemotaxonomic and modelling approaches, we show that these restratification events increase phytoplankton residence time in the sunlight zone, resulting in greater light interception and the emergence of winter blooms. Restratification also caused a phytoplankton community shift from pico- and nanophytoplankton to phototrophic diatoms. We conclude that transient winter blooms can maintain active diatom populations throughout the winter months, directly seeding the spring bloom and potentially making a significant contribution to over-winter carbon export.

  7. Chapter 7: Precipitation Change in the United States

    NASA Technical Reports Server (NTRS)

    Easterling, D. R.; Kunkel, K. E.; Arnold, J. R.; Knutson, T.; LeGrande, A. N.; Leung, L. R.; Vose, R. S.; Waliser, D. E.; Wehner, M. F.

    2017-01-01

    Annual precipitation has decreased in much of the West, Southwest, and Southeast and increased in most of the Northern and Southern Plains, Midwest, and Northeast. A national average increase of 4% in annual precipitation since 1901 is mostly a result of large increases in the fall season. Heavy precipitation events in most parts of the United States have increased in both intensity and frequency since 1901. There are important regional differences in trends, with the largest increases occurring in the northeastern United States. In particular, mesoscale convective systems (organized clusters of thunderstorms)-the main mechanism for warm season precipitation in the central part of the United States-have increased in occurrence and precipitation amounts since 1979. The frequency and intensity of heavy precipitation events are projected to continue to increase over the 21st century (high confidence). Mesoscale convective systems in the central United States are expected to continue to increase in number and intensity in the future. There are, however, important regional and seasonal differences in projected changes in total precipitation: the northern United States, including Alaska, is projected to receive more precipitation in the winter and spring, and parts of the southwestern United States are projected to receive less precipitation in the winter and spring. Northern Hemisphere spring snow cover extent, North America maximum snow depth, snow water equivalent in the western United States, and extreme snowfall years in the southern and western United States have all declined, while extreme snowfall years in parts of the northern United States have increased. Projections indicate large declines in snowpack in the western United States and shifts to more precipitation falling as rain than snow in the cold season in many parts of the central and eastern United States.

  8. 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

  9. [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.

  10. Processes regulating watershed chemical export during snowmelt, fraser experimental forest, Colorado

    USGS Publications Warehouse

    Stottlemyer, R.

    2001-01-01

    In the Central Rocky Mountains, snowfall dominates precipitation. Airborne contaminants retained in the snowpack can affect high elevation surface water chemistry during snowmelt. At the Fraser Experimental Forest (FEF), located west of the Continental Divide in Central Colorado, snowmelt dominates the annual hydrograph, and accounts for >95% of annual stream water discharge. During the winters of 1989-1993, we measured precipitation inputs, snowpack water equivalent (SWE) and ion content, and stream water chemistry every 7-10 days along a 3150-3500 m elevation gradient in the subalpine and alpine Lexen Creek watershed. The study objectives were to (1) quantify the distribution of SWE and snowpack chemical content with elevation and aspect, (2) quantify snowmelt rates, temperature of soil, snowpack, and air with elevation and aspect, and (3) use change in upstream-downstream water chemistry during snowmelt to better define alpine and subalpine flowpaths. The SWE increased with elevation (P - 3??C) temperatures throughout winter which resulted in significant snowpack ion loss. By snowpack PWE in mid May, the snowpack had lost almost half the cumulative precipitation H+, NH4+, and SO42- inputs and a third of the NO3- input. Windborne soil particulate inputs late in winter increased snowpack base cation content. Variation in subalpine SWE and snowpack ion content with elevation and aspect, and wind redistribution of snowfall in the alpine resulted in large year-to-year differences in the timing and magnitude of SWE, PWE, and snowpack ion content. The alpine stream water ion concentrations changed little during snowmelt indicating meltwater passed quickly through surface porous soils and was well mixed before entering the stream. Conversely, subalpine stream water chemistry was diluted during snowmelt suggesting much melt water moved to the stream as shallow subsurface lateral flow. Published by Elsevier Science B.V.

  11. Spatial Patterns of Snow Cover in North Carolina: Surface and Satellite Perspectives

    NASA Technical Reports Server (NTRS)

    Fuhrmann, Christopher M.; Hall, Dorothy K.; Perry, L. Baker; Riggs, George A.

    2010-01-01

    Snow mapping is a common practice in regions that receive large amounts of snowfall annually, have seasonally-continuous snow cover, and where snowmelt contributes significantly to the hydrologic cycle. Although higher elevations in the southern Appalachian Mountains average upwards of 100 inches of snow annually, much of the remainder of the Southeast U.S. receives comparatively little snowfall (< 10 inches). Recent snowy winters in the region have provided an opportunity to assess the fine-grained spatial distribution of snow cover and the physical processes that act to limit or improve its detection across the Southeast. In the present work, both in situ and remote sensing data are utilized to assess the spatial distribution of snow cover for a sample of recent snowfall events in North Carolina. Specifically, this work seeks to determine how well ground measurements characterize the fine-grained patterns of snow cover in relation to Moderate- Resolution Imaging Spectroradiometer (MODIS) snow cover products (in this case, the MODIS Fractional Snow Cover product).

  12. Chemical composition of snow in the east-central Sierra Nevada

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

    Brown, J.C.; Skau, C.M.

    1975-01-01

    The chemical quality of snowfall in the east-central Sierra Nevada mountains was measured four times at twenty-six sampling points during the period January to April 1975. Mean concentrations (ppM) and total production (lbs/mi2) of eleven major chemical constituents are reported. These values were related to six sampling site characteristics, using simple correlation techniques, to determine the factors which influence the chemical variability of snowfall over this area. Chemical concentrations in the snow here are, apparently, much lower than for precipitation reported in other parts of the country. Nitrogen and phosphorus concentrations, however, are similar to those found in small, easternmore » Sierra streams. The chemical concentrations in snowfall exhibit little variability between sampling sites. This suggests atmospheric concentrations of these constituents are relatively uniform over the area, with localized human activity having, apparently, little influence. The dominant factor causing variation of winter production values (lbs/mi2) between sites is simply the amount of precipitation.« less

  13. 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)

  14. Increased norovirus activity was associated with a novel norovirus GII.17 variant in Beijing, China during winter 2014-2015.

    PubMed

    Gao, Zhiyong; Liu, Baiwei; Huo, Da; Yan, Hanqiu; Jia, Lei; Du, Yiwei; Qian, Haikun; Yang, Yang; Wang, Xiaoli; Li, Jie; Wang, Quanyi

    2015-12-18

    Norovirus (NoV) is a leading cause of sporadic cases and outbreaks of acute gastroenteritis (AGE). Increased NoV activity was observed in Beijing, China during winter 2014-2015; therefore, we examined the epidemiological patterns and genetic characteristics of NoV in the sporadic cases and outbreaks. The weekly number of infectious diarrhea cases reported by all hospitals in Beijing was analyzed through the China information system for disease control and prevention. Fecal specimens were collected from the outbreaks and outpatients with AGE, and GI and GII NoVs were detected using real time reverse transcription polymerase chain reaction. The partial capsid genes and RNA-dependent RNA polymerase (RdRp) genes of NoV were both amplified and sequenced, and genotyping and phylogenetic analyses were performed. Between December 2014 and March 2015, the number of infectious diarrhea cases in Beijing (10,626 cases) increased by 35.6% over that of the previous year (7835 cases), and the detection rate of NoV (29.8%, 191/640) among outpatients with AGE was significantly higher than in the previous year (12.9%, 79/613) (χ(2) = 53.252, P < 0.001). Between November 2014 and March 2015, 35 outbreaks of AGE were reported in Beijing, and NoVs were detected in 33 outbreaks, all of which belonged to the GII genogroup. NoVs were sequenced and genotyped in 22 outbreaks, among which 20 were caused by a novel GII.17 strain. Among outpatients with AGE, this novel GII.17 strain was first detected in an outpatient in August 2014, and it replaced GII.4 Sydney_2012 as the predominant variant between December 2014 and March 2015. A phylogenetic analysis of the capsid genes and RdRp genes revealed that this novel GII.17 strain was distinct from previously identified GII variants, and it was recently designated as GII.P17_GII.17. This variant was further clustered into two sub-groups, named GII.17_2012 and GII.17_2014. During winter 2014-2015, GII.17_2014 caused the majority of AGE

  15. Long-term nitrogen fertilization increases winter injury in montane red spruce foliage (Picea rubens) foliage

    Treesearch

    T.D. Perkins; G.T. Adams; S.T. Lawson; P.G. Schaberg; S.G. McNulty

    2000-01-01

    Current-year red spruce (Picea rubens Sarg.) foliage is predisposed to winter injury by one or more types of anthropogenic pollutants, particularly acidic deposition. The resultant defoliation, when severe and repeated, leads to dieback and eventual mortality of affected red spruce individuals

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

    USGS Publications Warehouse

    Ward, David H.; Dau, Christian P.; Tibbitts, T. Lee; Sedinger, James S.; Anderson, Betty A.; Hines, James 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.

  17. Comparison of snowpack and winter wet-deposition chemistry in the Rocky Mountains, USA: Implications for winter dry deposition

    USGS Publications Warehouse

    Clow, David W.; Ingersoll, George P.; Mast, M. Alisa; Turk, John T.; Campbell, Donald 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.

  18. Comparison of snowpack and winter wet-deposition chemistry in the Rocky Mountains, USA: implications for winter dry deposition

    NASA Astrophysics Data System (ADS)

    Clow, David W.; Ingersoll, George P.; Mast, M. Alisa; Turk, John T.; Campbell, Donald H.

    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 SO 42- or NO 3- ( p>0.1). Small, but statistically significant differences ( p⩽0.03) were indicated for all other solutes analyzed. Differences were largest for Ca 2+ concentrations, which on average were 2.3 μeq l -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 μeq l -1 and a maximum of 12 μeq l -1 of snowpack acidity at the southernmost sites. The good agreement between snowpack and winter NADP/NTN SO 42- and NO 3- 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 SO 42- and NO 3- across the Rocky Mountain region.

  19. 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.

  20. 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

  1. Snow Bank Detectives

    ERIC Educational Resources Information Center

    Olson, Eric A.; Rule, Audrey C.; Dehm, Janet

    2005-01-01

    In the city where the authors live, located on the shore of Lake Ontario, children have ample opportunity to interact with snow. Water vapor rising from the relatively warm lake surface produces tremendous "lake effect" snowfalls when frigid winter winds blow. Snow piles along roadways after each passing storm, creating impressive snow…

  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.

  3. Daily movements of female mallards wintering in Southwestern Louisiana

    USGS Publications Warehouse

    Link, Paul T.; Afton, Alan D.; Cox, Robert R.; Davis, Bruce 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.

  4. Wintering ecology of adult North American ospreys

    USGS Publications Warehouse

    Washburn, Brian E.; Martell, Mark S.; Bierregaard, Richard O.; 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.

  5. The Role of Thermodynamic Processes in the Evolution of Single and Multi-banding within Winter Storms

    NASA Astrophysics Data System (ADS)

    Ganetis, Sara Anne

    Mesoscale precipitation bands within Northeast U.S. (NEUS) winter storms result in heterogeneous spatial and temporal snowfall. Several studies have provided analysis of snowbands focusing on larger, meso-beta scale bands with lengths (L) > 200 km known as single bands. NEUS winter storms can also exhibit multiple bands with meso-beta scale (L < 200 km) and similar spatial orientation and when ≥ 3 occur are termed multi-bands; however, the genesis and evolution of multi-bands is less well understood. Unlike single bands, there is no multi-bands climatological study. In addition, there has been little detailed thermodynamic analysis of snowbands. This dissertation utilizes radar observations, reanalyses, and high-resolution model simulations to explore the thermodynamic evolution of single and multi-bands. Bands are identified within 20 cool season (October-April) NEUS storms. The 110-case dataset was classified using a combination of automated and manual methods into: single band only (SINGLE), multi-bands only (MULTI), both single and multi-bands (BOTH), and non-banded (NONE). Multi-bands occur with the presence of a single band in 55.4% of times used in this study, without the presence of a single band 18.1% of the time, and precipitation exhibits no banded characteristics 23.8% of the time. Most MULTI events occur in the northeast quadrant of a developing cyclone poleward of weak-midlevel forcing along a warm front, whereas multi-bands associated with BOTH events mostly occur in the northwest quadrant of mature cyclones associated with strong mid-level frontogenesis and conditional symmetric instability. The non-banded precipitation associated with NONE events occur in the eastern quadrants of developing and mature cyclones lacking mid-level forcing to concentrate the precipitation into bands. A high-resolution mesoscale model is used to explore the evolution of single and multi-bands based on two case studies, one of a single band and one of multi-bands. The

  6. 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

  7. A review of regulations and guidelines related to winter manure application

    USDA-ARS?s Scientific Manuscript database

    Application of animal manure to frozen and snow-covered soils can increase the risk of nutrient losses and impairment of water quality in regions with hardy winters. In conjunction with global distributions of animal densities, we reviewed world-wide regulatory and voluntary guidelines on winter man...

  8. 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.

  9. Population ecology of the mallard VIII: Winter distribution patterns and survival rates of winter-banded mallards

    USGS Publications Warehouse

    Nichols, James D.; Hines, James E.

    1987-01-01

    In the present report we address questions about winter distribution patterns and survival rates of North American mallards Anas platyrhynchos. Inferences are based on analyses of banding and recovery data from both winter and preseason banding period. The primary wintering range of the mallard was dividded into 45 minor reference areas and 15 major reference areas which were used to summarize winter banding data. Descriptive tables and figures on the recovery distributions of winter-banded mallards are presented. Using winter recoveries of preseason-banded mallards, we found apparent differences between recovery distribution of young versus adult birds from the same breeding ground reference areas. However, we found no sex-specific differences in winter recovery distribution patterns. Winter recovery distributions of preseason-banded birds also provided evidence that mallards exhibited some degree of year-to-year variation in wintering ground location. The age- and sex-specificity of such variation was tested using winter recoveries of winter-banded birds, and results indicated that subadult (first year) birds were less likely to return to the same wintering grounds the following year than adults. Winter recovery distributions of preseason-banded mallards during 1950-58 differed from distributions in 1966-76. These differences could have resulted from either true distributional shifts or geographic changes in hunting pressure. Survival and recovery rates were estimated from winter banding data. We found no evidence of differences in survival or recovery rates between subadult and adult mallards. Thus, the substantial difference between survival rates of preseason-banded young and adult mallards must result almost entirely from higher mortality of young birds during the approximate period, August-January. Male mallards showed higher survival than females, corroborating inferences based on preseason data. Tests with winter banding and band recovery data indicated

  10. Winter climate change effects on soil C and N cycles in urban grasslands.

    PubMed

    Durán, Jorge; Rodríguez, Alexandra; Morse, Jennifer L; Groffman, Peter M

    2013-09-01

    Despite growing recognition of the role that cities have in global biogeochemical cycles, urban systems are among the least understood of all ecosystems. Urban grasslands are expanding rapidly along with urbanization, which is expected to increase at unprecedented rates in upcoming decades. The large and increasing area of urban grasslands and their impact on water and air quality justify the need for a better understanding of their biogeochemical cycles. There is also great uncertainty about the effect that climate change, especially changes in winter snow cover, will have on nutrient cycles in urban grasslands. We aimed to evaluate how reduced snow accumulation directly affects winter soil frost dynamics, and indirectly greenhouse gas fluxes and the processing of carbon (C) and nitrogen (N) during the subsequent growing season in northern urban grasslands. Both artificial and natural snow reduction increased winter soil frost, affecting winter microbial C and N processing, accelerating C and N cycles and increasing soil : atmosphere greenhouse gas exchange during the subsequent growing season. With lower snow accumulations that are predicted with climate change, we found decreases in N retention in these ecosystems, and increases in N2 O and CO2 flux to the atmosphere, significantly increasing the global warming potential of urban grasslands. Our results suggest that the environmental impacts of these rapidly expanding ecosystems are likely to increase as climate change brings milder winters and more extensive soil frost. © 2013 John Wiley & Sons Ltd.

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

    PubMed

    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.

  12. 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

  13. Winter maintenance performance measure.

    DOT National Transportation Integrated Search

    2016-01-01

    The Winter Performance Index is a method of quantifying winter storm events and the DOTs response to them. : It is a valuable tool for evaluating the States maintenance practices, performing post-storm analysis, training : maintenance personnel...

  14. 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…

  15. Incorporating Yearly Derived Winter Wheat Maps Into Winter Wheat Yield Forecasting Model

    NASA Technical Reports Server (NTRS)

    Skakun, S.; Franch, B.; Roger, J.-C.; Vermote, E.; Becker-Reshef, I.; Justice, C.; Santamaría-Artigas, A.

    2016-01-01

    Wheat is one of the most important cereal crops in the world. Timely and accurate forecast of wheat yield and production at global scale is vital in implementing food security policy. Becker-Reshef et al. (2010) developed a generalized empirical model for forecasting winter wheat production using remote sensing data and official statistics. This model was implemented using static wheat maps. In this paper, we analyze the impact of incorporating yearly wheat masks into the forecasting model. We propose a new approach of producing in season winter wheat maps exploiting satellite data and official statistics on crop area only. Validation on independent data showed that the proposed approach reached 6% to 23% of omission error and 10% to 16% of commission error when mapping winter wheat 2-3 months before harvest. In general, we found a limited impact of using yearly winter wheat masks over a static mask for the study regions.

  16. Winter weather demand considerations.

    DOT National Transportation Integrated Search

    2015-04-01

    Winter weather has varied effects on travel behavior. Using 418 survey responses from the Northern Virginia : commuting area of Washington, D.C. and binary logit models, this study examines travel related changes under : different types of winter wea...

  17. Effects of weather on habitat selection and behavior of mallards wintering in Nebraska

    USGS Publications Warehouse

    Jorde, Dennis 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.

  18. Fertilizer effects on a winter cereal cover crop

    USDA-ARS?s Scientific Manuscript database

    Benefits associated with conservation tillage in the Southeast are improved by using a winter cereal cover crop. In general, cover crop benefits increase as biomass production is increased, but the infertile soils typically require additional N (inorganic or organic). Currently, limited informatio...

  19. 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

  20. 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

  1. Deacclimation may be crucial for winter survival of cereals under warming climate.

    PubMed

    Rapacz, Marcin; Jurczyk, Barbara; Sasal, Monika

    2017-03-01

    Climate warming can change the winter weather patterns. Warmer temperatures during winter result in a lower risk of extreme freezing events. On the other hand the predicted warm gaps during winter will decrease their freezing tolerance. Both contradict effects will affect winter survival but their resultant effect is unclear. In this paper, we demonstrate that climate warming may result in a decrease in winter survival of plants. A field study of winterhardiness of common wheat and triticale was established at 11 locations and repeated during three subsequent winters. The freezing tolerance of the plants was studied after controlled cold acclimation and de-acclimation using both plant survival analysis and chlorophyll fluorescence measurements. Cold deacclimation resistance was shown to be independent from cold acclimation ability. Further, cold deacclimation resistance appeared to be crucial for overwintering when deacclimation conditions occurred in the field. The shortening of uninterrupted cold acclimation may increase cold deacclimation efficiency, which could threaten plant survival during warmer winters. Measurements of chlorophyll fluorescence transient showed some differences triggered by freezing before and after deacclimation. We conclude that cold deacclimation resistance should be considered in the breeding of winter cereals and in future models of winter damage risk. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

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

    PubMed

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

    2017-07-01

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

  3. NATURAL AND ATHROPOGENIC FACTORS AFFECTING GLOBAL AND REGIONAL CLIMATE

    EPA Science Inventory

    New England weather is highly variable for a number of
    reasons. Our regional climate is also quite variable. The
    winters of the past decade are milder than they were in the
    1960s and 1970s but as the ice-out and snowfall data show
    (Figs 2.5 and 2.6), the patterns of c...

  4. NOAA Photo Library - Meet the Photographers/Dr. Michael Van Woert

    Science.gov Websites

    , California. In January 1993 he assumed duties as the program scientist for the NASA TOPEX/POSEIDON altimeter mission and program manager for the Physical Oceanography Program at NASA Headquarters. The only snow and ice he encountered during the two years at NASA was above average winter snowfall on the streets of

  5. The influence of an extensive dust event on snow chemistry in the southern Rocky Mountains

    Treesearch

    Charles Rhoades; Kelly Elder; E. Greene

    2010-01-01

    In mid-February 2006, windstorms in Arizona, Utah, and western Colorado generated a dust cloud that distributed a layer of dust across the surface of the snowpack throughout much of the Colorado Rockies; it remained visible throughout the winter. We compared the chemical composition of snowfall and snowpack collected during and after the dust deposition event with pre-...

  6. Measuring soil frost depth in forest ecosystems with ground penetrating radar

    Treesearch

    John R. Butnor; John L. Campbell; James B. Shanley; Stanley Zarnoch

    2014-01-01

    Soil frost depth in forest ecosystems can be variable and depends largely on early winter air temperatures and the amount and timing of snowfall. A thorough evaluation of ecological responses to seasonally frozen ground is hampered by our inability to adequately characterize the frequency, depth, duration and intensity of soil frost events. We evaluated the use of...

  7. 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. © 2014 John Wiley & Sons Ltd.

  8. 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.

  9. Increasing carbon availability stimulates growth and secondary metabolites via modulation of phytohormones in winter wheat

    PubMed Central

    Reichelt, Michael; Chowdhury, Somak; Hammerbacher, Almuth; Hartmann, Henrik

    2017-01-01

    Abstract Phytohormones play important roles in plant acclimation to changes in environmental conditions. However, their role in whole-plant regulation of growth and secondary metabolite production under increasing atmospheric CO2 concentrations ([CO2]) is uncertain but crucially important for understanding plant responses to abiotic stresses. We grew winter wheat (Triticum aestivum) under three [CO2] (170, 390, and 680 ppm) over 10 weeks, and measured gas exchange, relative growth rate (RGR), soluble sugars, secondary metabolites, and phytohormones including abscisic acid (ABA), auxin (IAA), jasmonic acid (JA), and salicylic acid (SA) at the whole-plant level. Our results show that, at the whole-plant level, RGR positively correlated with IAA but not ABA, and secondary metabolites positively correlated with JA and JA-Ile but not SA. Moreover, soluble sugars positively correlated with IAA and JA but not ABA and SA. We conclude that increasing carbon availability stimulates growth and production of secondary metabolites via up-regulation of auxin and jasmonate levels, probably in response to sugar-mediated signalling. Future low [CO2] studies should address the role of reactive oxygen species (ROS) in leaf ABA and SA biosynthesis, and at the transcriptional level should focus on biosynthetic and, in particular, on responsive genes involved in [CO2]-induced hormonal signalling pathways. PMID:28159987

  10. Daylight and absenteeism--evidence from Norway.

    PubMed

    Markussen, Simen; Røed, Knut

    2015-01-01

    Based on administrative register data from Norway, we examine the impact of hours of daylight on sick-leave absences among workers. Our preferred estimates imply that an additional hour of daylight increases the daily entry rate to absenteeism by 0.5 percent and the corresponding recovery rate by 0.8 percent, ceteris paribus. The overall relationship between absenteeism and daylight hours is negative. Absenteeism is also sensitive to weather conditions. Heavy snowfall raises the incidence of absence during the winter, while warm weather reduces the probability of returning to work during the summer. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. The impact of winter heating on air pollution in China.

    PubMed

    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.

  12. Gullies in Winter Shadow

    NASA Image and Video Library

    2017-03-21

    This is an odd-looking image. It shows gullies during the winter while entirely in the shadow of the crater wall. Illumination comes only from the winter skylight. We acquire such images because gullies on Mars actively form in the winter when there is carbon dioxide frost on the ground, so we image them in the winter, even though not well illuminated, to look for signs of activity. The dark streaks might be signs of current activity, removing the frost, but further analysis is needed. NB: North is down in the cutout, and the terrain slopes towards the bottom of the image. The map is projected here at a scale of 50 centimeters (19.7 inches) per pixel. [The original image scale is 62.3 centimeters (24.5 inches) per pixel (with 2 x 2 binning); objects on the order of 187 centimeters (73.6 inches) across are resolved.] North is up. http://photojournal.jpl.nasa.gov/catalog/PIA21568

  13. Contrasting Response of Carbon Fluxes to Winter Warming across Land Cover Types in Southern NH, USA

    NASA Astrophysics Data System (ADS)

    Sanders-DeMott, R.; Ouimette, A.; Lepine, L. C.; Fogarty, S.; Burakowski, E. A.; Contosta, A.; Ollinger, S. V.; Conte, T.

    2017-12-01

    Natural and managed ecosystems play a key role in climate through regulation of carbon dioxide, as well as their effects on other greenhouse gases, surface heat fluxes, and albedo. In the northeastern United States, winter air temperatures are rising more rapidly than mean annual temperatures and the depth and duration of seasonal snowpack is decreasing. Although winter fluxes of carbon are small relative to the growing season, there is mounting evidence that biological processes in winter contribute significantly to annual ecosystem carbon budgets and that changes in winter conditions could lead to shifting patterns and magnitudes of seasonal carbon uptake. To determine the response of differing land cover types to variation in winter conditions we used eddy covariance to monitor carbon exchange from a co-located mixed temperate forest and a managed grassland in Durham, NH from 2014-2017, which included an anomalous warm winter (air temperatures 3°C warmer than 14-year mean) with low snowpack in 2016. We examined cumulative winter and spring net ecosystem exchange, as well as the sensitivity of ecosystem respiration to air and soil temperatures in the presence and absence of a deep (>15 cm) snowpack. We found that warm winter temperatures and low snow conditions led to relatively large cumulative losses of carbon from the forest in February/March 2016, while the grassland was a moderate net sink for carbon during the same period. When temperatures were above 0°C, mid-day carbon uptake in the grassland was controlled by the presence or absence of snow cover. Our results suggest that forest carbon losses to the atmosphere in deciduous forests may increase during warm, snow-free winter conditions when vegetation is restricted in winter carbon uptake capacity by phenology. However, non-forested vegetation such as perennial grasses have a greater potential to activate photosynthesis in winter and to take up carbon in the "dormant season," perhaps moderating

  14. Modeling large-scale winter recreation terrain selection with implications for recreation management and wildlife

    Treesearch

    Lucretia E. Olson; John R. Squires; Elizabeth K. Roberts; Aubrey D. Miller; Jacob S. Ivan; Mark Hebblewhite

    2017-01-01

    Winter recreation is a rapidly growing activity, and advances in technology make it possible for increasing numbers of people to access remote backcountry terrain. Increased winter recreation may lead to more frequent conflict between recreationists, as well as greater potential disturbance to wildlife. To better understand the environmental characteristics favored by...

  15. Winter CO2 efflux from cold semiarid sagebrush shrublands distributed across the rain-to-snow transition zone

    NASA Astrophysics Data System (ADS)

    Fellows, A.; Flerchinger, G. N.; Lohse, K. A.; Seyfried, M. S.

    2017-12-01

    Predicting winter CO2 efflux across the rain-to-snow transition zone is challenging in the cold semiarid northern Great Basin, USA, complicated by steep environmental gradients and marked heterogeneity in ecosystem properties. We therefore examined winter CO2 efflux over 9 site-years using 4 eddy covariance towers located in the Reynolds Creek Critical Zone Observatory. The sites were sagebrush shrublands located at 1425, 1680, 2098, and 2111 m, and spanned a large part of the rain-to-snow transition zone. We focused on two objectives. First, we quantified winter CO2 efflux at the sites, and considered how these varied with elevation. Second, we used a within-site and cross-site analysis to examine the biological and physical factors that impact winter CO2 efflux. Winter conditions were identified using temperature, snow depth, and CO2 exchange measurements and included 12,922 observations. The duration of winter conditions increased from 90 to 180 days with elevation. Peak snow depth increased from < 30 to > 100 cm with elevation. Cumulative winter CO2 efflux accounted for > 10% of the total annual CO2 efflux, increased with elevation, and was a key component of net ecosystem production at some sites in some years. The importance of winter CO2 efflux was accentuated by the region's long winters and also dry summers that decreased water availability and decomposition during non-winter periods. Preliminary regressions examining air temperature, soil temperature, wind speed, snow depth, and gross carbon uptake indicated some of these factors control the rate of winter CO2 efflux and require consideration, but that additional work is needed to disentangle co-linearity and assess the importance of these factors within and between sites. These findings suggest a consideration of winter CO2 efflux is warranted in cold winter-wet semiarid ecosystems, particularly where winters are long and non-winter CO2 efflux is strongly limited by water availability.

  16. Nowcasting of meteorological risks during the winter season using the "Integrated Meteorological Observation Network in Castilla y León, (Spain)"

    NASA Astrophysics Data System (ADS)

    Guerrero-Higueras, Ángel Manuel; López, Laura; Merino, Andrés; Sánchez, José Luis; Matía, Pedro; Lorente, José Manuel; Hermida, Lucía; Nafría, David; Ortiz de Galisteo, José Pablo; Marcos, José Luis; García-Ortega, Eduardo

    2013-04-01

    The location of Castilla y León within the Iberian Peninsula and its territorial extension make its meteorological risks diverse. The integration of various observation networks, both public and private, in the Observation Network of Castilla y León, allows us to follow the risks in real-time. One of the most frequent risks in the winter season is snow precipitation. In the present paper, we compared WRF numerical model predictions of snowfall for Castilla y León with data from the meteorological observation network and observations from the MSG satellite. Furthermore, frosts were more frequent in the area, to the point that there are parts of the study area with frost during the entire year. Thus, the data from the network allows us to determine the area where frost was registered. Finally, the situations with fog, especially with advective and radiative characteristics, are frequent in the center and south of the plateau, especially in the winter season. Additionally, the Observation Network allows us to know the areas with fog in real-time. The Observation Network is managed using a new platform, developed by Group for Atmospheric Physics, known as MeteoNet, which allows for the prompt extraction of a concrete parameter in a specific location, or, the spatial representation of a parameter determined for the entire study area. Furthermore, the management system developed for the data allows for the total representation of data from the WRF prediction model, with satellite images, observation network, radar data, etc., which is converted into a very useful tool for following risks and validating algorithms in Castilla y León. Acknowledgements The authors would like to thank the Regional Government of Castilla y León for its financial support through the project LE220A11-2.

  17. Hatchling turtles survive freezing during winter hibernation.

    PubMed Central

    Storey, K B; Storey, J M; Brooks, S P; Churchill, T A; Brooks, R J

    1988-01-01

    Hatchlings of the painted turtle (Chrysemys picta marginata) are unique as the only reptile and highest vertebrate life form known to tolerate the natural freezing of extracellular body fluids during winter hibernation. Turtles survived frequent exposures to temperatures as low as -6 degrees C to -8 degrees C in their shallow terrestrial nests over the 1987-1988 winter. Hatchlings collected in April 1988 had a mean supercooling point of -3.28 +/- 0.24 degrees C and survived 24 hr of freezing at -4 degrees C with 53.4% +/- 1.98% of total body water as ice. Recovery appeared complete after 20 hr of thawing at 3 degrees C. However, freezing at -10.9 degrees C, resulting in 67% ice, was lethal. A survey of possible cryoprotectants revealed a 2- to 3-fold increase in glucose content of liver and blood and a 3-fold increase in blood glycerol in response to freezing. Although quantitatively low, these responses by spring turtles strongly indicate that these may be the winter-active cryoprotectants. The total amino acid pool of blood also increased 2.25-fold in freezing-exposed turtles, and taurine accounted for 52% of the increase. Most organs accumulated high concentrations of lactate during freezing, a response to the ischemic state imposed by extracellular freezing. Changes in glycogen phosphorylase activity and levels of glucose 6-phosphate and fructose 2,6-bisphosphate were also consistent with a dependence on anaerobic glycolysis during freezing. Studies of the molecular mechanisms of natural freeze tolerance in these turtles may identify protective strategies that can be used in mammalian organ cryopreservation technology. PMID:3186730

  18. Climatic potential for tourism in the Black Forest, Germany--winter season.

    PubMed

    Endler, Christina; Matzarakis, Andreas

    2011-05-01

    Climate change, whether natural or human-caused, will have an impact on human life, including recreation and tourism among other things. In this study, methods from biometeorology and tourism climatology are used to assess the effect of a changed climate on tourism and recreation in particular. The study area is the Black Forest mountainous region of south-west Germany, which is well known for its tourist and recreational assets. Climate model projections for the 2021-2050 period based on REMO-UBA simulations with a high spatial resolution of 10 km are compared to a 30-year reference period (1971-2000) using the IPCC emission scenarios A1B and B1. The results show that the mean winter air temperature will increase by up to 1.8°C, which is the most pronounced warming compared to the other seasons. The annual precipitation amount will increase marginally by 5% in the A1B scenario and 10% in the B1 scenario. Winter precipitation contributes about 10% (A1B) and 30% (B1) to variations in annual precipitation. Although the results show that winter precipitation will increase slightly, snow days affecting skiing will be reduced on average by approximately 40% due to regional warming. Cold stress will be reduced on average by up to 25%. The result is that the thermal environment will be advanced, and warmer winters are likely to lead to an upward altitudinal shift of ski resorts and winter sport activities, thus displacing land-use currently dedicated to nature conservation.

  19. 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

  20. Marine assemblages respond rapidly to winter climate variability.

    PubMed

    Morley, James W; Batt, Ryan D; Pinsky, Malin L

    2017-07-01

    Even species within the same assemblage have varied responses to climate change, and there is a poor understanding for why some taxa are more sensitive to climate than others. In addition, multiple mechanisms can drive species' responses, and responses may be specific to certain life stages or times of year. To test how marine species respond to climate variability, we analyzed 73 diverse taxa off the southeast US coast in 26 years of scientific trawl survey data and determined how changes in distribution and biomass relate to temperature. We found that winter temperatures were particularly useful for explaining interannual variation in species' distribution and biomass, although the direction and magnitude of the response varied among species from strongly negative, to little response, to strongly positive. Across species, the response to winter temperature varied greatly, with much of this variation being explained by thermal preference. A separate analysis of annual commercial fishery landings revealed that winter temperatures may also impact several important fisheries in the southeast United States. Based on the life stages of the species surveyed, winter temperature appears to act through overwinter mortality of juveniles or as a cue for migration timing. We predict that this assemblage will be responsive to projected increases in temperature and that winter temperature may be broadly important for species relationships with climate on a global scale. © The Authors Global Change Biology Published by John Wiley & Sons Ltd.

  1. Potential Seasonal Predictability for Winter Storms over Europe

    NASA Astrophysics Data System (ADS)

    Wild, Simon; Befort, Daniel J.; Leckebusch, Gregor C.

    2017-04-01

    Reliable seasonal forecasts of strong extra-tropical cyclones and windstorms would have great social and economical benefits, as these events are the most costly natural hazards over Europe. In a previous study we have shown good agreement of spatial climatological distributions of extra-tropical cyclones and wind storms in state-of-the-art multi-member seasonal prediction systems with reanalysis. We also found significant seasonal prediction skill of extra-tropical cyclones and windstorms affecting numerous European countries. We continue this research by investigating the mechanisms and precursor conditions (primarily over the North Atlantic) on a seasonal time scale leading to enhanced extra-tropical cyclone activity and winter storm frequency over Europe. Our results regarding mechanisms show that an increased surface temperature gradient at the western edge of the North Atlantic can be related to enhanced winter storm frequency further downstream causing for example a greater number of storms over the British Isles, as observed in winter 2013-14.The so-called "Horseshoe Index", a SST tripole anomaly pattern over the North Atlantic in the summer months can also cause a higher number of winter storms over Europe in the subsequent winter. We will show results of AMIP-type sensitivity experiments using an AGCM (ECHAM5), supporting this hypothesis. Finally we will analyse whether existing seasonal forecast systems are able to capture these identified mechanisms and precursor conditions affecting the models' seasonal prediction skill.

  2. The importance of agricultural lands for Himalayan birds in winter.

    PubMed

    Elsen, Paul R; Kalyanaraman, Ramnarayan; Ramesh, Krishnamurthy; Wilcove, David S

    2017-04-01

    The impacts of land-use change on biodiversity in the Himalayas are poorly known, notwithstanding widespread deforestation and agricultural intensification in this highly biodiverse region. Although intact primary forests harbor many Himalayan birds during breeding, a large number of bird species use agricultural lands during winter. We assessed how Himalayan bird species richness, abundance, and composition during winter are affected by forest loss stemming from agriculture and grazing. Bird surveys along 12 elevational transects within primary forest, low-intensity agriculture, mixed subsistence agriculture, and intensively grazed pastures in winter revealed that bird species richness and abundance were greatest in low-intensity and mixed agriculture, intermediate in grazed pastures, and lowest in primary forest at both local and landscape scales; over twice as many species and individuals were recorded in low-intensity agriculture than in primary forest. Bird communities in primary forests were distinct from those in all other land-use classes, but only 4 species were unique to primary forests. Low-, medium-, and high-intensity agriculture harbored 32 unique species. Of the species observed in primary forest, 80% had equal or greater abundance in low-intensity agricultural lands, underscoring the value of these lands in retaining diverse community assemblages at high densities in winter. Among disturbed landscapes, bird species richness and abundance declined as land-use intensity increased, especially in high-intensity pastures. Our results suggest that agricultural landscapes are important for most Himalayan bird species in winter. But agricultural intensification-especially increased grazing-will likely result in biodiversity losses. Given that forest reserves alone may inadequately conserve Himalayan birds in winter, comprehensive conservation strategies in the region must go beyond protecting intact primary forests and ensure that low-intensity agricultural

  3. Snow accumulation on Arctic sea ice: is it a matter of how much or when?

    NASA Astrophysics Data System (ADS)

    Webster, M.; Petty, A.; Boisvert, L.; Markus, T.

    2017-12-01

    Snow on sea ice plays an important, yet sometimes opposing role in sea ice mass balance depending on the season. In autumn and winter, snow reduces the heat exchange from the ocean to the atmosphere, reducing sea ice growth. In spring and summer, snow shields sea ice from solar radiation, delaying sea ice surface melt. Changes in snow depth and distribution in any season therefore directly affect the mass balance of Arctic sea ice. In the western Arctic, a decreasing trend in spring snow depth distribution has been observed and attributed to the combined effect of peak snowfall rates in autumn and the coincident delay in sea ice freeze-up. Here, we build on this work and present an in-depth analysis on the relationship between snow accumulation and the timing of sea ice freeze-up across all Arctic regions. A newly developed two-layer snow model is forced with eight reanalysis precipitation products to: (1) identify the seasonal distribution of snowfall accumulation for different regions, (2) highlight which regions are most sensitive to the timing of sea ice freeze-up with regard to snow accumulation, and (3) show, if precipitation were to increase, which regions would be most susceptible to thicker snow covers. We also utilize a comprehensive sensitivity study to better understand the factors most important in controlling winter/spring snow depths, and to explore what could happen to snow depth on sea ice in a warming Arctic climate.

  4. Blowing Snow Sublimation at a High Altitude Alpine Site and Effects on the Surface Boundary Layer

    NASA Astrophysics Data System (ADS)

    Vionnet, V.; Guyomarc'h, G.; Sicart, J. E.; Deliot, Y.; Naaim-Bouvet, F.; Bellot, H.; Merzisen, H.

    2017-12-01

    In alpine terrain, wind-induced snow transport strongly influences the spatial and temporal variability of the snow cover. During their transport, blown snow particles undergo sublimation with an intensity depending on atmospheric conditions (air temperature and humidity). The mass loss due to blowing snow sublimation is a source of uncertainty for the mass balance of the alpine snowpack. Additionally, blowing snow sublimation modifies humidity and temperature in the surface boundary layer. To better quantify these effects in alpine terrain, a dedicated measurement setup has been deployed at the experimental site of Col du Lac Blanc (2720 m a.s.l., French Alps, Cryobs-Clim network) since winter 2015/2016. It consists in three vertical masts measuring the near-surface vertical profiles (0.2-5 m) of wind speed, air temperature and humidity and blowing snow fluxes and size distribution. Observations collected during blowing snow events without concurrent snowfall show only a slight increase in relative humidity (10-20%) and near-surface saturation is never observed. Estimation of blowing snow sublimation rates are then obtained from these measurements. They range between 0 and 5 mmSWE day-1 for blowing snow events without snowfall in agreement with previous studies in different environments (North American prairies, Antarctica). Finally, an estimation of the mass loss due to blowing snow sublimation at our experimental site is proposed for two consecutive winters. Future use of the database collected in this study includes the evaluation of blowing snow models in alpine terrain.

  5. 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

  6. 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

  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.; 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. Drivers of River Water Temperature Space-time Variability in Northeast Greenland

    NASA Astrophysics Data System (ADS)

    Hannah, D. M.; Docherty, C.; Milner, A.

    2015-12-01

    Water temperature plays an important role in stream ecosystem functioning; however, water temperature dynamics in high Arctic environments have received relatively little attention. Given that global climate is predicted to change most at high latitudes, it is vital we broaden our knowledge of space-time variability in Arctic river temperature to understand controlling processes and potential consequences of climate change. To address this gap, our research aims: (1) to characterise seasonal and diel patterns of variability over three summer and two winter seasons with contrasting hydrometeorological conditions, (2) to unravel the key drivers influencing thermal regimes and (3) to place these results in the context of other snow/ glacier-melt dominated environments. Fieldwork was undertaken in July-September 2013, 2014 and 2015 close to the Zackenberg Research Station in Northeast Greenland - an area of continuous permafrost with a mean July air temperature of 6 °C. Five streams were chosen that drain different water source contributions (glacier melt, snow melt, groundwater). Data were collected at 30 minute intervals using micro-dataloggers. Air temperature data were collected within 7km by the Greenland Survey. Weather conditions were highly variable between field campaigns, with 2013 experiencing below average, and 2014 and 2015 above average, snowfall. Summer water temperatures appear to be high in comparison to some Arctic streams in Alaska and in Svalbard. Winter snowfall extent decreases stream water temperature; and water temperature increases with atmospheric exposure time (distance from source) - illustrating the intertwined controls of water and heat fluxes. These Greenland streams are most strongly influenced by snowmelt, but groundwater contributions could increase with a changing climate due to increased active layer thickness, which may result in increased river temperature with implications for aquatic biodiversity and ecosystem functioning.

  9. 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.

  10. 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.

  11. Predictability of ENSO, the QBO, and European winter 2015/16

    NASA Astrophysics Data System (ADS)

    Scaife, A. A.; Ineson, S.; Ruth, C.; Dunstone, N. J.; Fereday, D.; Folland, C. K.; Good, E.; Gordon, M.; Hermanson, L.; Karpechko, A.; Knight, J. R.; MacLachlan, C.; Maidens, A. V.; Peterson, A.; Slingo, J.; Smith, D.; Walker, B.

    2016-12-01

    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.

  12. Impacts of extreme winter warming events on plant physiology in a sub-Arctic heath community.

    PubMed

    Bokhorst, Stef; Bjerke, Jarle W; Davey, Matthew P; Taulavuori, Kari; Taulavuori, Erja; Laine, Kari; Callaghan, Terry V; Phoenix, Gareth K

    2010-10-01

    Insulation provided by snow cover and tolerance of freezing by physiological acclimation allows Arctic plants to survive cold winter temperatures. However, both the protection mechanisms may be lost with winter climate change, especially during extreme winter warming events where loss of snow cover from snow melt results in exposure of plants to warm temperatures and then returning extreme cold in the absence of insulating snow. These events cause considerable damage to Arctic plants, but physiological responses behind such damage remain unknown. Here, we report simulations of extreme winter warming events using infrared heating lamps and soil warming cables in a sub-Arctic heathland. During these events, we measured maximum quantum yield of photosystem II (PSII), photosynthesis, respiration, bud swelling and associated bud carbohydrate changes and lipid peroxidation to identify physiological responses during and after the winter warming events in three dwarf shrub species: Empetrum hermaphroditum, Vaccinium vitis-idaea and Vaccinium myrtillus. Winter warming increased maximum quantum yield of PSII, and photosynthesis was initiated for E. hermaphroditum and V. vitis-idaea. Bud swelling, bud carbohydrate decreases and lipid peroxidation were largest for E. hermaphroditum, whereas V. myrtillus and V. vitis-idaea showed no or less strong responses. Increased physiological activity and bud swelling suggest that sub-Arctic plants can initiate spring-like development in response to a short winter warming event. Lipid peroxidation suggests that plants experience increased winter stress. The observed differences between species in physiological responses are broadly consistent with interspecific differences in damage seen in previous studies, with E. hermaphroditum and V. myrtillus tending to be most sensitive. This suggests that initiation of spring-like development may be a major driver in the damage caused by winter warming events that are predicted to become more

  13. Simulated hydrologic response to climate change during the 21st century in New Hampshire

    USGS Publications Warehouse

    Bjerklie, David M.; Sturtevant, Luke P.

    2018-01-24

    The U.S. Geological Survey, in cooperation with the New Hampshire Department of Environmental Services and the Department of Health and Human Services, has developed a hydrologic model to assess the effects of short- and long-term climate change on hydrology in New Hampshire. This report documents the model and datasets developed by using the model to predict how climate change will affect the hydrologic cycle and provide data that can be used by State and local agencies to identify locations that are vulnerable to the effects of climate change in areas across New Hampshire. Future hydrologic projections were developed from the output of five general circulation models for two future climate scenarios. The scenarios are based on projected future greenhouse gas emissions and estimates of land-use and land-cover change within a projected global economic framework. An evaluation of the possible effect of projected future temperature on modeling of evapotranspiration is summarized to address concerns regarding the implications of the future climate on model parameters that are based on climate variables. The results of the model simulations are hydrologic projections indicating increasing streamflow across the State with large increases in streamflow during winter and early spring and general decreases during late spring and summer. Wide spatial variability in changes to groundwater recharge is projected, with general decreases in the Connecticut River Valley and at high elevations in the northern part of the State and general increases in coastal and lowland areas of the State. In general, total winter snowfall is projected to decrease across the State, but there is a possibility of increasing snow in some locations, particularly during November, February, and March. The simulated future changes in recharge and snowfall vary by watershed across the State. This means that each area of the State could experience very different changes, depending on topography or other

  14. Comparisons of Modeled and Observed Reflectivities and Fall Speeds for Snowfall of Varied Riming Degree During Winter Storms on Long Island, New York

    NASA Technical Reports Server (NTRS)

    Molthan, Andrew L.; Colle, Brian A.; Yuter, Sandra E.; Stark, David

    2016-01-01

    Derived radar reflectivity and fall speed for four Weather Research and Forecasting model bulk microphysical parameterizations (BMPs) run at 1.33 km grid spacing are compared with ground-based, vertically-pointing Ku-band radar, scanning S- band radar, and in situ measurements at Stony Brook, NY. Simulations were partitioned into periods of observed riming degree as determined manually using a stereo microscope and camera during nine winter storms. Simulations were examined to determine whether the selected BMPs captured the effects of varying riming intensities, provided a reasonable match to the vertical structure of radar reflectivity or fall speed, and whether they produced reasonable surface fall speed distributions. Schemes assuming non spherical mass-diameter relationships yielded reflectivity distributions closer to observed values. All four schemes examined in this study provided a better match to the observed, vertical structure of reflectivity during moderate riming than light riming periods. The comparison of observed and simulated snow fall speeds had mixed results. One BMP produced episodes of excessive cloud water at times, resulting in fall speeds that were too large. However, most schemes had frequent periods of little or no cloud water during moderate riming periods and thus underpredicted the snow fall speeds at lower levels. Short, 1-4 hour periods with relatively steady snow conditions were used to compare BMP and observed size and fall speed distributions. These limited data suggest the examined BMPs underpredict fall speeds of cold-type snow habits and underrepresent aggregates larger than 4 mm diameter.

  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. 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.

  17. 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.

  18. Comparison of estimates of snow input to a small alpine watershed

    Treesearch

    R. A. Sommerfeld; R. C. Musselman; G. L. Wooldridge

    1990-01-01

    We have used five methods to estimate the snow water equivalent input to the Glacier Lakes Ecosystem Experiments Site (GLEES) in south-central Wyoming during the winter 1987-1988 and to obtain an estimate of the errors. The methods are: (1) the Martinec and Rango degree-day method; (2) Wooldridge et al. method of determining the average yearly snowfall from tree...

  19. 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…

  20. Body composition and weight dynamics of wintering greater white-fronted geese

    USGS Publications Warehouse

    Ely, Craig R.; Raveling, Dennis G.

    1989-01-01

    Adult greater white-fronted geese (Anser albifrons frontalis) wintering in southern Oregon and California increased or maintained body weight in autumn, lost weight from autumn through winter, and rapidly increased in weight before spring migration in late April. We documented significant annual differences in body weights for both sexes. We related seasonal changes in body weight to changes in lipid levels, which were lowest (12-13% of wet wt in M and F) in mid-March and highest in late April (24% in F). Greater white-fronted geese maintained lipid levels during winter similar to those reported for large subspecies of Canada geese (Branta canadensis), and greater than those reported for small subspecies of Canada geese and other small species of geese. Protein content of carcasses varied significantly in females; i.e., lowest in early October and highest in late October and late April. Differences among species in patterns of weight change and body composition during winter seem to be related to social organization, body size, food type, and foraging behavior. Females left spring staging areas weighing relatively less than most other species of geese and may have benefited from foraging opportunities on the nesting grounds.

  1. Periphyton dynamics in a subalpine mountain stream during winter

    USGS Publications Warehouse

    Gustina, G.W.; Hoffmann, J.P.

    2000-01-01

    We conducted two experiments to determine the activity of and factors which control periphyton during winter in Stevensville Brook, Vermont. The first experiment during winter/spring 1994 examined the effect of a 300 to 450% difference in light and doubling of flow (low and high light, slow and fast flow) on periphyton chlorophyll a (chl a) and ash-free dry mass (AFDM) from stream rocks and artificial substrata. A second experiment was performed to determine whether periphyton was nitrogen or phosphorus limited. In addition, stream water was sampled during fall/winter 1994/95 for nitrate (NO3), ammonia (NH4), soluble reactive phosphorus (SRP), and total phosphorus (TP) to determine the availability of nutrients in Stevensville Brook. Increases of up to 250% for AFDM and 600% for chl a during the first study indicated robust activity throughout the winter despite low temperatures and light. Flow had a negative effect and sampling date was found to have a significant effect on periphyton biomass (chl a and AFDM) while light was found to influence increases in AFDM on clay tiles only. Water analyses showed that SRP was less than 0.001 mg L-1, NH4 and TP were low and often undetectable, and NO3 remained at about 0.20 mg L-1. Results from the nutrient enrichment experiment showed a significant response of chl a to P but not N and no response of AFDM to enrichment with either N or P. In Stevensville Brook during winter, the algal community, as represented by the chl a concentration, is predominantly controlled by phosphorus concentrations and is influenced to a lesser extent by flow; the periphyton community as a whole, represented by AFDM, is controlled mostly by stream flow and light.

  2. Increasing carbon availability stimulates growth and secondary metabolites via modulation of phytohormones in winter wheat.

    PubMed

    Huang, Jianbei; Reichelt, Michael; Chowdhury, Somak; Hammerbacher, Almuth; Hartmann, Henrik

    2017-02-01

    Phytohormones play important roles in plant acclimation to changes in environmental conditions. However, their role in whole-plant regulation of growth and secondary metabolite production under increasing atmospheric CO2 concentrations ([CO2]) is uncertain but crucially important for understanding plant responses to abiotic stresses. We grew winter wheat (Triticum aestivum) under three [CO2] (170, 390, and 680 ppm) over 10 weeks, and measured gas exchange, relative growth rate (RGR), soluble sugars, secondary metabolites, and phytohormones including abscisic acid (ABA), auxin (IAA), jasmonic acid (JA), and salicylic acid (SA) at the whole-plant level. Our results show that, at the whole-plant level, RGR positively correlated with IAA but not ABA, and secondary metabolites positively correlated with JA and JA-Ile but not SA. Moreover, soluble sugars positively correlated with IAA and JA but not ABA and SA. We conclude that increasing carbon availability stimulates growth and production of secondary metabolites via up-regulation of auxin and jasmonate levels, probably in response to sugar-mediated signalling. Future low [CO2] studies should address the role of reactive oxygen species (ROS) in leaf ABA and SA biosynthesis, and at the transcriptional level should focus on biosynthetic and, in particular, on responsive genes involved in [CO2]-induced hormonal signalling pathways. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  3. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  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. Research on best practices for winter weather operations.

    DOT National Transportation Integrated Search

    2012-10-01

    There is a growing need to identify actionable practices relative to winter weather operations. Because of the : potential and inherent hazards during cold weather, it has become increasingly important to ensure that these : practices can be effectiv...

  6. Responses of Plant Community Composition to Long-term Changes in Snow Depth at the Great Basin Desert - Sierra Nevada ecotone.

    NASA Astrophysics Data System (ADS)

    Loik, M. E.

    2015-12-01

    Snowfall is the dominant hydrologic input for many high-elevation ecosystems of the 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. Given the importance of snowfall for future carbon cycling in high elevation ecosystems, how will these changes affect seedling recruitment, plant mortality, and community composition? To address this question, experiments utilize snow fences to manipulate snow depth and melt timing at a desert-montane ecotone in eastern California, USA. Long-term April 1 snow pack depth averages 1344 mm (1928-2015) but is highly variable from year to year. Snow fences increased equilibrium drift snow depth by 100%. Long-term changes in snow depth and melt timing are associated with s shift from shurbs to graminoids where snow depth was increased for >50 years. Changes in snow have impacted growth for only three plant species. Moreover, annual growth ring increments of the conifers Pinus jeffreyi and Pi. contorta were not equally sensitive to snow depth. There were over 8000 seedlings of the shrubs Artemisia tridentata and Purshia tridentata found in 6300 m2 in summer 2009, following about 1400 mm of winter snow and spring rain. The frequency of seedlings of A. tridentata and P. tridentata were much lower on increased-depth plots compared to ambient-depth, and reduced-depth plots. Survival of the first year was lowest for A. tridentata. Survival of seedlings from the 2008 cohort was much higher for P. tridentata than A. tridentata during the 2011-2015 drought. Results indicate complex interactions between snow depth and plant community characteristics, and that responses of plants at this ecotone may not respond similarly to increases vs. decreases in snow depth. These changes portend altered carbon uptake in this region under future snowfall scenarios.

  7. Changes in Biochemical Properties of the Blood in Winter Swimmers.

    PubMed

    Teleglow, Aneta; Marchewka, Jakub; Marchewka, Anna; Kulpa, Jan

    The aim of the study was to investigate the effects of winter swimming on biochemical indicators of the blood. The subjects - winter swimmers - belonged to the Krakow Walrus Club "Kaloryfer" - "The Heater". The study group consisted of 11 men, aged 30-50 years, 'walrusing' throughout the whole season from November to March. Statistically significant changes throughout the 'walrusing' season were observed for the following biochemical parameters: a decrease in sodium (mmol/1), chloride (mmol/1), alpha-2 globulin(g/1), gamma globulin (g/1), IgG (g/1), and an increase in albumin (g/1), indicator A/G, IgA (g/l ), Herpes simplex virus IgM. Seasonal effort of winter swimmers has a positive influence on biochemical blood parameters.

  8. View from Space Shows Winter Storm Sweep Over U.S. East Coast

    NASA Image and Video Library

    2015-03-05

    A winter storm was bringing snow, sleet and freezing rain from lower Mississippi Valley to Northeastern U.S. on Thursday, March 5, 2015. A new NASA animation of NOAA's GOES-East satellite imagery showed the progression of the clouds associated with the storm system that triggered winter storm warnings and winter weather advisories from the southern Plains eastward through the Mid-Atlantic and southern New England coast. The system also triggered flood warnings along and to the west of the central Appalachians. An animation of GOES satellite visible and infrared imagery from March 3 through March 5 showed clouds associated with a cold front push over U.S. East coast. Behind the front, Arctic air is expected to drop low temperatures into the single numbers from Washington, D.C. to Minnesota overnight. Temperatures in the Carolinas and Tennessee are expected to drop to the low 20s. NOAA's National Weather Service Weather Prediction Center (NWS NPC) in College Park, Maryland noted "a strong cold front moving across the eastern U.S. will bring heavy snow from parts of the Ohio Valley to the Northeast today (March 5) with rain, freezing rain and sleet possible from parts of the lower Mississippi Valley across the Southeast to the southern Mid-Atlantic. Snowfall totals of 5 to 10 inches are possible for some areas. Winter Storm Warnings remain in effect from Texas to Nantucket." The animation ends at 17:45 UTC (12:45 p.m. EST). Before the end of the animation, the low pressure center along an arctic frontal boundary was nearly stationary over western North Carolina at 9 a.m. EST on March 5, according to the NWS NPC. NWS radar and surface observations indicated an extended swath of precipitation from near the Texas Gulf Coast through the interior eastern U.S. into southern New England. NPC's storm summary noted at that time "rain was changing to sleet/freezing rain and to all snow along a band within this swath as colder air continues to filter in from the north. Some

  9. Towards better understanding of high-mountain cryosphere changes using GPM data: A Joint Snowfall and Snow-cover Passive Microwave Retrieval Algorithm

    NASA Astrophysics Data System (ADS)

    Ebtehaj, A.; Foufoula-Georgiou, E.

    2016-12-01

    Scientific evidence suggests that the duration and frequency of snowfall and the extent of snow cover are rapidly declining under global warming. Both precipitation and snow cover scatter the upwelling surface microwave emission and decrease the observed high-frequency brightness temperatures. The mixture of these two scattering signals is amongst the largest sources of ambiguities and errors in passive microwave retrievals of both precipitation and snow-cover. The dual frequency radar and the high-frequency radiometer on board the GPM satellite provide a unique opportunity to improve passive retrievals of precipitation and snow-cover physical properties and fill the gaps in our understating of their variability in view of climate change. Recently, a new Bayesian rainfall retrieval algorithm (called ShARP) was developed using modern approximation methods and shown to yield improvements against other algorithms in retrieval of rainfall over radiometrically complex land surfaces. However, ShARP uses a large database of input rainfall and output brightness temperatures, which might be undersampled. Furthermore, it is not capable to discriminate between solid and liquid phase of precipitation and specifically discriminate the background snow-cover emission and its contamination effects on the retrievals. We address these problems by extending it to a new Bayesian land-atmosphere retrieval framework (ShARP-L) that allows joint retrievals of atmospheric constituents and land surface physical properties. Using modern sparse approximation techniques, the database is reduced to atomic microwave signatures in a family of compact class consistent dictionaries. These dictionaries can efficiently represent the entire database and allow us to discriminate between different land-atmosphere states. First the algorithm makes use of the dictionaries to detect the phase of the precipitation and type of the land-cover and then it estimates the physical properties of precipitation and

  10. Climatic potential for tourism in the Black Forest, Germany — winter season

    NASA Astrophysics Data System (ADS)

    Endler, Christina; Matzarakis, Andreas

    2011-05-01

    Climate change, whether natural or human-caused, will have an impact on human life, including recreation and tourism among other things. In this study, methods from biometeorology and tourism climatology are used to assess the effect of a changed climate on tourism and recreation in particular. The study area is the Black Forest mountainous region of south-west Germany, which is well known for its tourist and recreational assets. Climate model projections for the 2021-2050 period based on REMO-UBA simulations with a high spatial resolution of 10 km are compared to a 30-year reference period (1971-2000) using the IPCC emission scenarios A1B and B1. The results show that the mean winter air temperature will increase by up to 1.8°C, which is the most pronounced warming compared to the other seasons. The annual precipitation amount will increase marginally by 5% in the A1B scenario and 10% in the B1 scenario. Winter precipitation contributes about 10% (A1B) and 30% (B1) to variations in annual precipitation. Although the results show that winter precipitation will increase slightly, snow days affecting skiing will be reduced on average by approximately 40% due to regional warming. Cold stress will be reduced on average by up to 25%. The result is that the thermal environment will be advanced, and warmer winters are likely to lead to an upward altitudinal shift of ski resorts and winter sport activities, thus displacing land-use currently dedicated to nature conservation.

  11. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. 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.

  13. 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.

  14. Upper lethal temperatures in three cold-tolerant insects are higher in winter than in summer.

    PubMed

    Vu, Henry M; Duman, John G

    2017-08-01

    Upper lethal temperatures (ULTs) of cold-adapted insect species in winter have not been previously examined. We anticipated that as the lower lethal temperatures (LLTs) decreased (by 20-30°C) with the onset of winter, the ULTs would also decrease accordingly. Consequently, given the recent increases in winter freeze-thaw cycles and warmer winters due to climate change, it became of interest to determine whether ambient temperatures during thaws were approaching ULTs during the cold seasons. However, beetle Dendroides canadensis (Coleoptera: Pyrochroidae) larvae had higher 24 and 48 h ULT 50 (the temperature at which 50% mortality occurred) in winter than in summer. The 24 and 48 h ULT 50 for D. canadensis in winter were 40.9 and 38.7°C, respectively. For D. canadensis in summer, the 24 and 48 h ULT 50 were 36.7 and 36.4°C. During the transition periods of spring and autumn, the 24 h ULT 50 was 37.3 and 38.5°C, respectively. While D. canadensis in winter had a 24 h LT 50 range between LLT and ULT of 64°C, the summer range was only 41°C. Additionally, larvae of the beetle Cucujus clavipes clavipes (Coleoptera: Cucujidae) and the cranefly Tipula trivittata (Diptera: Tipulidae) also had higher ULTs in winter than in summer. This unexpected phenomenon of increased temperature survivorship at both lower and higher temperatures in the winter compared with that in the summer has not been previously documented. With the decreased high temperature tolerance as the season progresses from winter to summer, it was observed that environmental temperatures are closest to upper lethal temperatures in spring. © 2017. Published by The Company of Biologists Ltd.

  15. Winter diarrhoea and rotaviruses in Rhodesia.

    PubMed

    Cruickshank, J G; Zilberg, G

    1976-11-06

    In the winter fewer bacterial pathogens are isolated from patients with gastro-enteritis than in the summer. The incidence of rotavirus infection is, however, at its greatest during the winter months and the virus is rarely found in cases of gastro-enteritis which occur during the warm season. The clinical pattern in winter diarrhoea is characteristically severe and acute but there has been no mortality or cross-infection.

  16. Nutritional composition and in vitro digestibility of grass and legume winter (cover) crops.

    PubMed

    Brown, A N; Ferreira, G; Teets, C L; Thomason, W E; Teutsch, C D

    2018-03-01

    In dairy farming systems, growing winter crops for forage is frequently limited to annual grasses grown in monoculture. The objectives of this study were to determine how cropping grasses alone or in mixtures with legumes affects the yield, nutritional composition, and in vitro digestibility of fresh and ensiled winter crops and the yield, nutritional composition, and in vitro digestibility of the subsequent summer crops. Experimental plots were planted with 15 different winter crops at 3 locations in Virginia. At each site, 4 plots of each treatment were planted in a randomized complete block design. The 15 treatments included 5 winter annual grasses [barley (BA), ryegrass (RG), rye (RY), triticale (TR), and wheat (WT)] in monoculture [i.e., no legumes (NO)] or with 1 of 2 winter annual legumes [crimson clover (CC) and hairy vetch (HV)]. After harvesting the winter crops, corn and forage sorghum were planted within the same plots perpendicular to the winter crop plantings. The nutritional composition and the in vitro digestibility of winter and summer crops were determined for fresh and ensiled samples. Growing grasses in mixtures with CC increased forage dry matter (DM) yield (2.84 Mg/ha), but the yield of mixtures with HV (2.47 Mg/ha) was similar to that of grasses grown in monoculture (2.40 Mg/ha). Growing grasses in mixtures with legumes increased the crude protein concentration of the fresh forage from 13.0% to 15.5% for CC and to 17.3% for HV. For neutral detergent fiber (NDF) concentrations, the interaction between grasses and legumes was significant for both fresh and ensiled forages. Growing BA, RY, and TR in mixtures with legumes decreased NDF concentrations, whereas growing RG and WT with legumes did not affect the NDF concentrations of either the fresh or the ensiled forages. Growing grasses in mixtures with legumes decreased the concentration of sugars of fresh forages relative to grasses grown in monoculture. Primarily, this decrease can be

  17. Changes in trumpeter swan (Cygnus buccinator) activities from winter to spring in the greater Yellowstone area

    Treesearch

    John R. Squires; Stanley H. Anderson

    1997-01-01

    Trumpeter swans (Cygnus buccinator), in the winter, primarily, slept 42% of the time, fed 30%, swam 12%; and preened 7%. Comparisons of swan activities among die periods during the winter indicated they increased feeding throughout the day into night, when they fed at their highest rate. Swans spent more time sleeping as winter temperatures decreased; feeding...

  18. 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

  19. Disturbance to wintering western snowy plovers

    USGS Publications Warehouse

    Lafferty, Kevin 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.

  20. The Modification of Orographic Snow Growth Processes by Cloud Nucleating Aerosols

    NASA Astrophysics Data System (ADS)

    Cotton, W. R.; Saleeby, S.

    2011-12-01

    synoptic flow simply provides the background dynamics and moisture that impinge upon the steep terrain. The addition of cloud nucleating aerosols to this scenario tends to reduce the amount of riming and leads to greater snow vapor growth. Increased vapor growth leads to larger snow crystals but does not necessarily increase their density or fall speed. There is frequently a zone on the periphery of the orographic cloud where water saturation is low and ice saturation remains high. Here the Bergeron process allows for snow to continue growing at the expense of the cloud water. Furthermore, since less cloud water is removed by riming, and droplets are smaller in polluted conditions, there is an increase in cloud water evaporation along the lee slope. This enhanced droplet evaporation in polluted conditions allows for more saturated air to persist to the lee of the ridge. Higher saturation reduces the amount of snow crystal sublimation prior to surface deposition. In very moist winter events, the lee slope evaporation relative to the primary mountain barrier can saturate the air relative to a downstream ridge and aid in further orographic cloud development. The combination of reduced riming, the Bergeron process, and reduced lee-side sublimation leads to the snowfall spillover effect under polluted conditions.

  1. Water resources in the Great Basin

    Treesearch

    Jeanne C. Chambers

    2008-01-01

    The Great Basin Watershed covers 362,600 km (140,110 mi2) and extends from the Sierra Nevada Range in California to the Wasatch Range in Utah, and from southeastern Oregon to southern Nevada (NBC Weather Plus Website). The region is among the driest in the nation and depends largely on winter snowfall and spring runoff for its water supply. Precipitation may be as much...

  2. Post-wildfire summer greening depends on winter snowpack

    NASA Astrophysics Data System (ADS)

    Wilson, A.; Nolin, A. W.

    2017-12-01

    Forested, mountain landscapes in the Pacific Northwest (PNW) are changing at an unprecedented rate, largely due to shifts in the regional climate regime. Documented climatic trends include increasing wildfire frequency and intensity and an increasingly ephemeral snowpack, especially at moderate elevations. One relationship that has yet to be studied thoroughly is the dependence of post-wildfire forest recovery on winter snowpack. This study will correlate winter snowpack with summer greenness in the context of 15 recent severe wildfires across the PNW. Winter snow water equivalent will be estimated using a new Snow Cover Frequency (SCF) metric derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) daily snow cover product. Summer forest greenness will be assessed using the Enhanced Vegetation Index (EVI), also derived from daily MODIS reflectance data. Regression tree analysis will be employed to characterize the relative importance of snowpack, elevation, slope, aspect, soil texture, and summer precipitation to summer greenness. Using findings from the regression tree analysis, the most critical physiographic factors will frame a multivariate time series spanning the 5 years pre-wildfire and 5 years post-wildfire in an effort to illustrate how the snowpack-revegetation relationship persists over time. As northwestern mountainous forests become more vulnerable to wildfire activity, it will be vital to continue deepening our understanding of how snowpack matters to post-wildfire forest recovery.

  3. Winter cover crops influence Amaranthus palmeri establishment

    USDA-ARS?s Scientific Manuscript database

    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...

  4. Record low total ozone during northern winters of 1992 and 1993

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

    Bojkov, R.D.

    1993-07-09

    The authors look at recorded ozone data over the northern hemisphere during the winters of 1992 and 1993. They use data from the World Meteorological Organization data base. During both of these winter, there have been marked decreases in the column ozone levels over North America, Europe, and Siberia, in the latitude belt from 45[degrees]N to 65[degrees]N. During these winters there have been ten times as many days with ozone levels deviated more than 2[sigma] below the 35 year average. They seek explanations for these observations by looking at meterological information. Evidences indicate that there was transport of ozone deficientmore » air masses during these winters. In addition cold air masses with excess ClO show evidence of having transported into the more southern latitudes. The authors conclude there is evidence for both displacement of large air masses, and increased chemical destruction potential, to have contributed to these observed decreases.« less

  5. Molecular cloning and characterization of preproorexin in winter skate (Leucoraja ocellata).

    PubMed

    MacDonald, Erin E; Volkoff, Hélène

    2010-12-01

    A 815 base pairs (bp) cDNA encoding for preproorexin (preproOX) was cloned in winter skate, a cartilaginous fish. Winter skate preproOX is 159 amino acids (aa) long and contains a 34 aa orexin A and 28 aa orexin B. The amino acid sequence of winter skate preproOX is more similar to tetrapod preproOXs (36-40% identity) than teleost preproOXs (23-33% identity). Whereas orexin B appears relatively well conserved among vertebrates, orexin A displays more variability, in particular due to an "insertion sequence" that is present in teleost fish, but not in skate and tetrapods. RT-PCR studies show that preproOX mRNA has a widespread distribution within the brain and is present in several peripheral tissues, including gastrointestinal tract, heart and testes. Fasting induced increases in preproOX expression in the hypothalamus, suggesting that orexin might play a role in the regulation of food intake in winter skate. Copyright © 2010 Elsevier Inc. All rights reserved.

  6. Snowpack chemistry at selected sites in Colorado and New Mexico during winter 1999-2000

    USGS Publications Warehouse

    Ingersoll, George P.

    2000-01-01

    Snowpacks at two high-elevation (> 3,000 m) sampling sites near McPhee and Sanchez Reservoirs in southern Colorado were selected to collect representative samples of atmospheric deposition to the surrounding watersheds during winter 1999-2000. In February 2000, annual snowpacks at two sites were sampled to determine concentrations of nitrate and sulfate; concentrations of the trace elements arsenic, mercury, and selenium; and the sulfur isotope ratios that result from atmospheric deposition to the area. Snowpack chemistry data at the two sites sampled in 1999-2000 are compared to 1993-99 averages at 10 other snow-sampling sites in Colorado and New Mexico that generally are downwind of the Four Corners area of the southwestern United States. Although concentrations of ammonium and nitrate in the 1999-2000 snowpacks were fairly typical compared to averages established at nearby sites in southern Colorado and northern New Mexico, chloride and sulfate concentrations were below the 1993-99 average, while arsenic, mercury, and selenium in snow were much below the 1993-99 average. However, very similar sulfur-isotope ratios (that are not a function of precipitation amounts) deposited in snowpacks at the nearby sites indicate the snowpack chemistries at the new sampling locations near McPhee and Sanchez reservoirs were affected by similar sources of sulfate. Representative samples of coal burned during the 1999-2000 snowfall season at three power plants near Four Corners also were analyzed for sulfur content and trace elements. Results from separate, independent laboratories show similar concentrations and provide an initial baseline that will be used for general comparisons of coal chemistry to snowpack chemistry.

  7. Simulating the influences of various fire regimes on caribou winter habitat

    USGS Publications Warehouse

    Rupp, T. Scott; Olson, Mark; Adams, Layne G.; Dale, Bruce W.; Joly, Kyle; Henkelman, Jonathan; Collins, William B.; Starfield, Anthony M.

    2006-01-01

    Caribou are an integral component of high‐latitude ecosystems and represent a major subsistence food source for many northern people. The availability and quality of winter habitat is critical to sustain these caribou populations. Caribou commonly use older spruce woodlands with adequate terrestrial lichen, a preferred winter forage, in the understory. Changes in climate and fire regime pose a significant threat to the long‐term sustainability of this important winter habitat. Computer simulations performed with a spatially explicit vegetation succession model (ALFRESCO) indicate that changes in the frequency and extent of fire in interior Alaska may substantially impact the abundance and quality of winter habitat for caribou. We modeled four different fire scenarios and tracked the frequency, extent, and spatial distribution of the simulated fires and associated changes to vegetation composition and distribution. Our results suggest that shorter fire frequencies (i.e., less time between recurring fires) on the winter range of the Nelchina caribou herd in eastern interior Alaska will result in large decreases of available winter habitat, relative to that currently available, in both the short and long term. A 30% shortening of the fire frequency resulted in a 3.5‐fold increase in the area burned annually and an associated 41% decrease in the amount of spruce–lichen forest found on the landscape. More importantly, simulations with more frequent fires produced a relatively immature forest age structure, compared to that which currently exists, with few stands older than 100 years. This age structure is at the lower limits of stand age classes preferred by caribou from the Nelchina herd. Projected changes in fire regime due to climate warming and/or additional prescribed burning could substantially alter the winter habitat of caribou in interior Alaska and lead to changes in winter range use and/or population dynamics.

  8. 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

  9. Climate change affects winter chill for temperate fruit and nut trees.

    PubMed

    Luedeling, Eike; Girvetz, Evan H; Semenov, Mikhail A; Brown, Patrick H

    2011-01-01

    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. 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. 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.

  10. A Prognostic Methodology for Precipitation Phase Detection using GPM Microwave Observations —With Focus on Snow Cover

    NASA Astrophysics Data System (ADS)

    Takbiri, Z.; Ebtehaj, A.; Foufoula-Georgiou, E.; Kirstetter, P.

    2017-12-01

    Improving satellite retrieval of precipitation requires increased understanding of its passive microwave signature over different land surfaces. Passive microwave signals over snow-covered surfaces are notoriously difficult to interpret because they record both emission from the land below and absorption/scattering from the liquid/ice crystals. Using data from the Global Precipitation Measurement (GPM) core satellite, we demonstrate that the microwave brightness temperatures of rain and snowfall shifts from a scattering to an emission regime from summer to winter, due to expansion of the less emissive snow cover underneath. We present evidence that the combination of low- (10-19 GHz) and high-frequency (89-166 GHz) channels provides the maximum amount of information for snowfall detection. The study also examines a prognostic nearest neighbor matching method for the detection of precipitation and its phase from passive microwave observations using GPM data. The nearest neighbor uses the weighted Euclidean distance metric to search through an a priori database that is populated with coincident GPM radiometer and radar data as well as ancillary snow cover fraction. The results demonstrate prognostic capabilities of the proposed method in detection of terrestrial snowfall. At the global scale, the average probability of hit and false alarm reaches to 0.80 and remains below 0.10, respectively. Surprisingly, the results show that the snow cover may help to better detect precipitation as the detection rate of terrestrial precipitation is increased from 0.75 (no snow cover) to 0.84 (snow-covered surfaces). For solid precipitation, this increased rate of detection is larger than its liquid counterpart by almost 8%. The main reasons are found to be related to the multi-frequency capabilities of the nearest neighbor matching that can properly isolate the atmospheric signal from the background emission and the fact that the precipitation can exhibit an emission-like (warmer

  11. Aggressiveness Changes in Populations of Didymella pinodes over Winter and Spring Pea Cropping Seasons

    PubMed Central

    Laloi, G.; Montarry, J.; Guibert, M.; Andrivon, D.; Michot, D.

    2016-01-01

    ABSTRACT Ascochyta blight, caused by the necrotrophic ascomycete Didymella pinodes, is responsible for severe losses in winter and spring pea crops. Despite different climatic conditions, epidemics on winter and spring crops are due to a single population of D. pinodes, suggesting gene flow either between the two crops or from reservoir sources during the cropping season. This should lead to similar pathogenicity characteristics in isolates sampled from the two crops. However, these hypotheses have never been formally tested. We therefore sampled a total of 520 D. pinodes strains throughout a growing season from winter and spring pea plots (WP and SP, respectively) and from winter and spring trap plants (TWP and TSP). Amplified fragment length polymorphism (AFLP) markers revealed high genetic diversity within subpopulations, whereas pathogenicity tests showed that mean aggressiveness increases over the course of an epidemic. These results support the idea that alloinoculum contributes to the carryover of epidemics between winter and spring crops and that the most aggressive isolates are selected as an epidemic progresses. IMPORTANCE Ascochyta blight, caused by Didymella pinodes, is responsible for severe losses in pea crops. While previous studies have shown that ascochyta blight epidemics on winter and spring crops are due to a single population of D. pinodes, suggesting that isolates from the two crops present similar pathogenicity characteristics, that hypothesis have never been tested. Genetic analysis of subpopulations sampled throughout a growing season from winter and spring pea plots revealed high genetic diversity within subpopulations, whereas pathogenicity tests showed that mean aggressiveness increases over the course of an epidemic. PMID:27208102

  12. Livable Winter Cities--Leisure Attitudes and Activities.

    ERIC Educational Resources Information Center

    Neal, Larry; Coles, Roger, Ed.

    1989-01-01

    The nine articles included in this feature emphasize how leisure, recreation, health and physical activities make winter cities more livable. Specific topics include techniques for teaching about cold weather safety and cold related injuries, Arctic Winter Games, and results of a study on winter recreation in large North American communities. (IAH)

  13. Interannual variability and predictability over the Arabian Penuinsula Winter monsoon region

    NASA Astrophysics Data System (ADS)

    Adnan Abid, Muhammad; Kucharski, Fred; Almazroui, Mansour; Kang, In-Sik

    2016-04-01

    Interannual winter rainfall variability and its predictability are analysed over the Arabian Peninsula region by using observed and hindcast datasets from the state-of-the-art European Centre for Medium-Range Weather Forecasts (ECMWF) seasonal prediction System 4 for the period 1981-2010. An Arabian winter monsoon index (AWMI) is defined to highlight the Arabian Peninsula as the most representative region for the Northern Hemispheric winter dominating the summer rainfall. The observations show that the rainfall variability is relatively large over the northeast of the Arabian Peninsula. The correlation coefficient between the Nino3.4 index and rainfall in this region is 0.33, suggesting potentially some modest predictability, and indicating that El Nino increases and La Nina decreases the rainfall. Regression analysis shows that upper-level cyclonic circulation anomalies that are forced by El Nino Southern Oscillation (ENSO) are responsible for the winter rainfall anomalies over the Arabian region. The stronger (weaker) mean transient-eddy activity related to the upper-level trough induced by the warm (cold) sea-surface temperatures during El Nino (La Nina) tends to increase (decrease) the rainfall in the region. The model hindcast dataset reproduces the ENSO-rainfall connection. The seasonal mean predictability of the northeast Arabian rainfall index is 0.35. It is shown that the noise variance is larger than the signal over the Arabian Peninsula region, which tends to limit the prediction skill. The potential predictability is generally increased in ENSO years and is, in particular, larger during La Nina compared to El Nino years in the region. Furthermore, central Pacific ENSO events and ENSO events with weak signals in the Indian Ocean tend to increase predictability over the Arabian region.

  14. Development of a model system to identify differences in spring and winter oat.

    PubMed

    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.

  15. Early stage de-etiolation increases the ferulic acid content in winter triticale seedlings under full sunlight conditions.

    PubMed

    Hura, Tomasz; Hura, Katarzyna; Grzesiak, Maciej

    2010-12-02

    In the presented work an attempt has been made to estimate the phenolics content and its implication for the protection of the photosynthetic apparatus in course of a plant's de-etiolation. The experiments were carried out on two genotypes of winter triticale varying in their resistance to drought. The activity of the photosynthetic apparatus was monitored by taking measurements of chlorophyll fluorescence and chlorophyll/carotenoids content. Analyses of the total pool of phenolic compounds and ferulic acid as well as l-phenylalanine ammonia lyase activity were completed. The first illuminations of etiolated seedlings induced a chlorophyll synthesis, which was followed by the increasing activity of the photosynthetic apparatus in both studied genotypes. Piano exhibited a higher values of the maximum quantum efficiency of photosystem II primary photochemistry during de-etiolation than Imperial. These results may just indicate that for Imperial, the delivery of photons to the reaction centres exceeded the capacity of the photosynthetic apparatus to transduce this energy via electron transport. An increase in the content of ferulic acid was more noticeable for Piano and seems to be a consequence of adaptation to the new light conditions. It should be taken into account, that an increase of ferulic acid content during early stage of de-etiolation, may limit the photoinhibition of photosynthesis whenever radiation is excessive for the photosynthetic apparatus. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. 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

  17. Winter distribution of willow flycatcher subspecies

    USGS Publications Warehouse

    Paxton, E.H.; Unitt, P.; Sogge, M.K.; Whitfield, M.; Keim, P.

    2011-01-01

    Documenting how different regions across a species' breeding and nonbreeding range are linked via migratory movements is the first step in understanding how events in one region can influence events in others and is critical to identifying conservation threats throughout a migratory animal's annual cycle. We combined two studies that evaluated migratory connectivity in the Willow Flycatcher (Empidonax traillii), one using mitochondrial DNA sequences from 172 flycatchers sampled throughout their winter range, and another which examined morphological characteristics of 68 museum specimens collected in the winter range. Our results indicate that the four subspecies occupy distinct but overlapping regions of the winter range. Connectivity between specific breeding and winter grounds appears to be moderate to strong, with distributions that suggest migration patterns of both the chain and leap-frog types connecting the breeding and nonbreeding grounds. The Pacific lowlands of Costa Rica appear to be a key winter location for the endangered Southwestern Willow Flycatcher (E. t. extimus), although other countries in Central America may also be important for the subspecies. ?? The Cooper Ornithological Society 2011.

  18. Examining winter visitor use in Yellowstone National Park

    Treesearch

    Mae A. Davenport; Wayne A. Freimund; William T. Borrie; Robert E. Manning; William A. Valliere; Benjamin Wang

    2000-01-01

    This research was designed to assist the managers of Yellowstone National Park (YNP) in their decision making about winter visitation. The focus of this report is on winter use patterns and winter visitor preferences. It is the author’s hope that this information will benefit both the quality of winter experiences and the stewardship of the park resources. This report...

  19. Aircraft Survivability: Protecting and Integrating Air and Space, Winter 2001/2002

    DTIC Science & Technology

    2002-01-01

    1. Transparent Aerogel JT CG /A S Sp on so re d Pr oj ec t Aircraft Survivability • Winter 2001/2002 11 enable computers to become faster by...for rotorcraft. The program was co-funded by JTCG/AS starting in 2001 as part of the tri- service Aerogels for Retrofitted Increase in Aircraft ...site at www.aiaa.org/tc/sur/ index.html. See you there! Aircraft Survivability • Winter 2001/2002 19 Aerogels have other properties that could

  20. Waterfowl density on agricultural fields managed to retain water in winter

    USGS Publications Warehouse

    Twedt, D.J.; Nelms, C.O.

    1999-01-01

    Managed water on private and public land provides habitat for wintering waterfowl in the Mississippi Valley, where flood control projects have reduced the area of natural flooding. We compared waterfowl densities on rice, soybean, and moist-soil fields under cooperative agreements to retain water from 1 November through 28 February in Arkansas and Mississippi and assessed temporal changes in waterfowl density during winter in 1991-1992 and 1992-1993. Fields flooded earlier in Arkansas, but retained water later in Mississippi. Over winter, waterfowl densities decreased in Arkansas and increased in Mississippi. Densities of waterfowl, including mallard (Anas platyrhynchos), the most abundant species observed, were greatest on moist-soil fields. However, soybean fields had the greatest densities of northern shoveler (Spatula clypeata).

  1. Plasticity in body temperature and metabolic capacity sustains winter activity in a small endotherm (Rattus fuscipes).

    PubMed

    Glanville, Elsa J; Seebacher, Frank

    2010-03-01

    Small mammals that remain active throughout the year at a constant body temperature have a much greater energy and food requirement in winter. Lower body temperatures in winter may offset the increased energetic cost of remaining active in the cold, if cellular metabolism is not constrained by a negative thermodynamic effect. We aimed to determine whether variable body temperatures can be advantageous for small endotherms by testing the hypothesis that body temperature fluctuates seasonally in a wild rat (Rattus fuscipes); conferring an energy saving and reducing food requirements during resource restricted winter. Additionally we tested whether changes in body temperature affected tissue specific metabolic capacity. Winter acclimatized rats had significantly lower body temperatures and thicker fur than summer acclimatized rats. Mitochondrial oxygen consumption and the activity of enzymes that control oxidative (citrate synthase, cytochrome c-oxidase) and anaerobic (lactate dehydrogenase) metabolism were elevated in winter and were not negatively affected by the lower body temperature. Energy transfer modeling showed that lower body temperatures in winter combined with increased fur thickness to confer a 25 kJ day(-1) energy saving, with up to 50% owing to reduced body temperature alone. We show that phenotypic plasticity at multiple levels of organization is an important component of the response of a small endotherm to winter. Mitochondrial function compensates for lower winter body temperatures, buffering metabolic heat production capacity. Copyright 2009 Elsevier Inc. All rights reserved.

  2. Winter warming delays dormancy release, advances budburst, alters carbohydrate metabolism and reduces yield in a temperate shrub

    PubMed Central

    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

  3. 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

    2015-03-23

    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

  4. 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.

  5. Seasonal cues induce phenotypic plasticity of Drosophila suzukii to enhance winter survival.

    PubMed

    Shearer, Peter W; West, Jessica D; Walton, Vaughn M; Brown, Preston H; Svetec, Nicolas; Chiu, Joanna C

    2016-03-22

    As global climate change and exponential human population growth intensifies pressure on agricultural systems, the need to effectively manage invasive insect pests is becoming increasingly important to global food security. Drosophila suzukii is an invasive pest that drastically expanded its global range in a very short time since 2008, spreading to most areas in North America and many countries in Europe and South America. Preliminary ecological modeling predicted a more restricted distribution and, for this reason, the invasion of D. suzukii to northern temperate regions is especially unexpected. Investigating D. suzukii phenology and seasonal adaptations can lead to a better understanding of the mechanisms through which insects express phenotypic plasticity, which likely enables invasive species to successfully colonize a wide range of environments. We describe seasonal phenotypic plasticity in field populations of D. suzukii. Specifically, we observed a trend of higher proportions of flies with the winter morph phenotype, characterized by darker pigmentation and longer wing length, as summer progresses to winter. A laboratory-simulated winter photoperiod and temperature (12:12 L:D and 10 °C) were sufficient to induce the winter morph phenotype in D. suzukii. This winter morph is associated with increased survival at 1 °C when compared to the summer morph, thus explaining the ability of D. suzukii to survive cold winters. We then used RNA sequencing to identify gene expression differences underlying seasonal differences in D. suzukii physiology. Winter morph gene expression is consistent with known mechanisms of cold-hardening such as adjustments to ion transport and up-regulation of carbohydrate metabolism. In addition, transcripts involved in oogenesis and DNA replication were down-regulated in the winter morph, providing the first molecular evidence of a reproductive diapause in D. suzukii. To date, D. suzukii cold resistance studies suggest that this

  6. Is parental competitive ability in winter negatively affected by previous springs' family size?

    PubMed

    Fokkema, Rienk W; Ubels, Richard; Tinbergen, Joost M

    2017-03-01

    Reproductive behavior cannot be understood without taking the local level of competition into account. Experimental work in great tits ( Parus major ) showed that (1) a survival cost of reproduction was paid in environments with high levels of competition during the winter period and (2) experimentally manipulated family size negatively affected the ability of parents to compete for preferred breeding boxes in the next spring. The fact that survival was affected in winter suggests that the competitive ability of parents in winter may also be affected by previous reproductive effort. In this study, we aim to investigate whether (1) such carryover effects of family size on the ability of parents to compete for resources in the winter period occurred and (2) this could explain the occurrence of a survival cost of reproduction under increased competition. During two study years, we manipulated the size of in total 168 great tit broods. Next, in winter, we induced competition among the parents by drastically reducing the availability of roosting boxes in their local environment for one week. Contrary to our expectation, we found no negative effect of family size manipulation on the probability of parents to obtain a roosting box. In line with previous work, we did find that a survival cost of reproduction was paid only in plots in which competition for roosting boxes was shortly increased. Our findings thus add to the scarce experimental evidence that survival cost of reproduction are paid under higher levels of local competition but this could not be linked to a reduced competitive ability of parents in winter.

  7. 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.

  8. 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.

  9. Effect of Irrigation to Winter Wheat on the Radiation Use Efficiency and Yield of Summer Maize in a Double Cropping System

    PubMed Central

    Quanqi, Li; Yuhai, Chen; Xunbo, Zhou; Songlie, Yu; Changcheng, Guo

    2012-01-01

    In north China, double cropping of winter wheat and summer maize is a widely adopted agricultural practice, and irrigation is required to obtain a high yield from winter wheat, which results in rapid aquifer depletion. In this experiment conducted in 2001-2002, 2002-2003, and 2004-2005, we studied the effects of irrigation regimes during specific winter wheat growing stage with winter wheat and summer maize double cropping systems; we measured soil moisture before sowing (SMBS), the photosynthetic active radiation (PAR) capture ratio, grain yield, and the radiation use efficiency (RUE) of summer maize. During the winter wheat growing season, irrigation was applied at the jointing, heading, or milking stage, respectively. The results showed that increased amounts of irrigation and irrigation later in the winter wheat growing season improved SMBS for summer maize. The PAR capture ratio significantly (LSD, P < 0.05) increased with increased SMBS, primarily in the 3 spikes leaves. With improved SMBS, both the grain yield and RUE increased in all the treatments. These results indicate that winter wheat should be irrigated in later stages to achieve reasonable grain yield for both crops. PMID:22654613

  10. Aggregated responses of human mobility to severe winter storms: An empirical study.

    PubMed

    Wang, Yan; Wang, Qi; Taylor, John E

    2017-01-01

    Increasing frequency of extreme winter storms has resulted in costly damages and a disruptive impact on the northeastern United States. It is important to understand human mobility patterns during such storms for disaster preparation and relief operations. We investigated the effects of severe winter storms on human mobility during a 2015 blizzard using 2.69 million Twitter geolocations. We found that displacements of different trip distances and radii of gyration of individuals' mobility were perturbed significantly. We further explored the characteristics of perturbed mobility during the storm, and demonstrated that individuals' recurrent mobility does not have a higher degree of similarity with their perturbed mobility, when comparing with its similarity to non-perturbed mobility. These empirical findings on human mobility impacted by severe winter storms have potential long-term implications on emergency response planning and the development of strategies to improve resilience in severe winter storms.

  11. Preceding winter La Niña reduces Indian summer monsoon rainfall

    NASA Astrophysics Data System (ADS)

    Chakraborty, Arindam

    2018-05-01

    Leaving out the strong El Niño Southern Oscillation (ENSO) years, our understanding in the interannual variation of the Indian summer monsoon rainfall (ISMR) stands poor for the rest. This study quantifies the role of ENSO in the preceding winter on ISMR with a particular emphasis on ENSO-neutral summer and La Niña winter. Results show that, unlike the simultaneous ENSO-ISMR relationship, La Niña of previous winter reduces mean rainfall over the country by about 4% even during ENSO neutral summer. Moreover, when ENSO changes phase from La Niña in winter to El Niño in summer, ISMR is anomalously lower than during persisting El Niño years (‑14.5% and ‑5.3%, respectively), increasing the probability of severe drought. This suppression effect of La Niña of the preceding winter on summer monsoon precipitation over India is mostly experienced in its western and southern parts. Principal component analysis of the zonal propagation of surface pressure anomalies from winter to summer along Northern Hemisphere subtropics decomposes interannual variations of seasonally persisting anomalies from zonal propagations. The dominant modes are associated with the seasonal transition of the ENSO phase, and are well correlated with date of onset and seasonal mean rainfall of monsoon over India. These results improve our understanding of the interannual variations of ISMR and could be used for diagnostics of general circulation models.

  12. Preparations for Severe Winter Conditions by Emergency Health Personnel in Turkey.

    PubMed

    Calışkan, Cüneyt; Algan, Aysun; Koçak, Hüseyin; Biçer, Burcu Küçük; Sengelen, Meltem; Cakir, Banu

    2014-04-23

    Emergency and core ambulance personnel work under all environmental conditions, including severe weather condtions. We evaluated emergency medical personnel in Çanakkale, Turkey, for their degree of preparedness. A descriptive study was conducted in Çanakkale, Turkey, within 112 emergency service units and their 17 district stations. Surveys were developed to measure the level of preparedness for serious winter conditions that individual workers made for themselves, their homes, and their cars. Of the 167 survey participants, the mean age was 29.8 ± 7.9 years; 52.7% were women; more than half (54.75%) were emergency medical technicians; and 53.3% were married. Only 10.4% of those who heated their homes with natural gas had carbon monoxide detectors. Scores relating to household and individual preparation for severe winter conditions increased by participants' age (P < .003), being married (P < .000) and working in the city center (P < .021); and for men whose cars were equipped with tow ropes, extra clothing, and snow tires (P < .05). Absenteeism was higher for central-city personnel than district workers because they were less prepared for harsh winter conditions (P = .016). Many of the surveyed emergency health personel demonstrated insufficient preparations for serious winter conditions. To increase the safety and efficiency of emergency medical personnel, educational training programs should be rountinely conducted. (Disaster Med Public Health Preparedness. 2014;0:1-4).

  13. Depletion of rice as food of waterfowl wintering in the Mississippi Alluvial Valley

    USGS Publications Warehouse

    Greer, Danielle M.; Dugger, Bruce D.; Reinecke, Kenneth J.; Petrie, Mark J.

    2009-01-01

    Waterfowl habitat conservation strategies in the Mississippi Alluvial Valley (MAV) and several other wintering areas assume carrying capacity is limited by available food, and increasing food resources is an effective conservation goal. Because existing research on winter food abundance and depletion is insufficient to test this hypothesis, we used harvested rice fields as model foraging habitats to determine if waste rice seed is depleted before spring migration. We sampled rice fields (n = 39 [winter 2000-2001], n = 69 [2001-2002]) to estimate seed mass when waterfowl arrived in late autumn and departed in late winter. We also placed exclosures in subsets of fields in autumn (n = 8 [2000-2001], n = 20 [2001-2002]) and compared seed mass inside and outside exclosures in late winter to estimate rice depletion attributable to waterfowl and other processes. Finally, we used an experiment to determine if the extent of rice depletion differed among fields of varying initial abundance and if the seed mass at which waterfowl ceased foraging or abandoned fields differed from a hypothesized giving-up value of 50 kg/ha. Mean seed mass was greater in late autumn 2000 than 2001 (127.0 vs. 83.9 kg/ha; P = 0.018) but decreased more during winter 2000-2001 than 2001-2002 (91.3 vs. 55.7 kg/ha) and did not differ at the end of winter (35.8 vs. 28.3 kg/ha; P = 0.651). Assuming equal loss to deterioration inside and outside exclosures, we estimated waterfowl consumed 61.3 kg/ha (48.3%) of rice present in late autumn 2000 and 21.1 kg/ha (25.1%) in 2001. When we manipulated late-autumn rice abundance, mean giving-up mass of rice seed was similar among treatments (48.7 kg/ha; P = 0.205) and did not differ from 50 kg/ha (P = 0.726). We integrated results by constructing scenarios in which waterfowl consumed rice at different times in winter, consumption and deterioration were competing risks, and consumption occurred only above 50 kg/ha. Results indicated waterfowl likely consumed

  14. Short-term winter wheat (Triticum aestivum L.) cover crop grazing influence on calf growth, grain yield, and soil properties

    USDA-ARS?s Scientific Manuscript database

    Winter cover cropping has many agronomic benefits and can provide forages base for spring livestock grazing. Winter cover crop grazing has shown immediate economic benefits through increased animal production. Winter wheat pasture grazing is common in beef cow-calf production and stocker operations....

  15. Projecting the impact of climate change on phenology of winter wheat in northern Lithuania

    NASA Astrophysics Data System (ADS)

    Juknys, Romualdas; Velička, Rimantas; Kanapickas, Arvydas; Kriaučiūnienė, Zita; Masilionytė, Laura; Vagusevičienė, Ilona; Pupalienė, Rita; Klepeckas, Martynas; Sujetovienė, Gintarė

    2017-10-01

    Climate warming and a shift in the timing of phenological phases, which lead to changes in the duration of the vegetation period may have an essential impact on the productivity of winter crops. The main purpose of this study is to examine climate change-related long-term (1961-2015) changes in the duration of both initial (pre-winter) and main (post-winter) winter wheat vegetation seasons and to present the projection of future phenological changes until the end of this century. Delay and shortening of pre-winter vegetation period, as well as the advancement and slight extension of the post-winter vegetation period, resulted in the reduction of whole winter wheat vegetation period by more than 1 week over the investigated 55 years. Projected changes in the timing of phenological phases which define limits of a main vegetation period differ essentially from the observed period. According to pessimistic (Representative Concentration Pathways 8.5) scenario, the advancement of winter wheat maturity phase by almost 30 days and the shortening of post-winter vegetation season by 15 days are foreseen for a far (2071-2100) projection. An increase in the available chilling amount is specific not only to the investigated historical period (1960-2015) but also to the projected period according to the climate change scenarios of climate warming for all three projection periods. Consequently, the projected climate warming does not pose a threat of plant vernalization shortage in the investigated geographical latitudes.

  16. 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.

  17. Northern pintail body condition during wet and dry winters in the Sacramento Valley, California

    USGS Publications Warehouse

    Miller, M.R.

    1986-01-01

    Body weights and carcass composition of male and female adult northern pintails (Anas acuta) were investigated in the Sacramento Valley, California, from August to March 1979-82. Pintails were lightweight, lean, and had reduced breast, leg, and heart muscles during August-September. Ducks steadily gained weight after arrival; and body, carcass (body wt minus feathers and gastrointestinal content), fat protein, and muscle weights peaked in October-November. Fat-free dry weight remained high but variable the rest of the winter, whereas body and carcass weight and fat content declined to lows in December or January, then increased again in February or March. Gizzard weights declined from early fall to March. Males were always heavier than females, but females were fatter (percentage) than males during mid-winter. Mid-winter body weight, carcass fat, and protein content were significantly (P < 0.01) lower in the dry winter of 1980-81 than in 2 wet winters (1979-80 and 1981-82). Changes in pintail body weight and composition during winter are probably adaptations to mild climate, predictable food supplies, and requirements for pair formation and molt.

  18. Aggressiveness Changes in Populations of Didymella pinodes over Winter and Spring Pea Cropping Seasons.

    PubMed

    Laloi, G; Montarry, J; Guibert, M; Andrivon, D; Michot, D; Le May, C

    2016-07-15

    Ascochyta blight, caused by the necrotrophic ascomycete Didymella pinodes, is responsible for severe losses in winter and spring pea crops. Despite different climatic conditions, epidemics on winter and spring crops are due to a single population of D. pinodes, suggesting gene flow either between the two crops or from reservoir sources during the cropping season. This should lead to similar pathogenicity characteristics in isolates sampled from the two crops. However, these hypotheses have never been formally tested. We therefore sampled a total of 520 D. pinodes strains throughout a growing season from winter and spring pea plots (WP and SP, respectively) and from winter and spring trap plants (TWP and TSP). Amplified fragment length polymorphism (AFLP) markers revealed high genetic diversity within subpopulations, whereas pathogenicity tests showed that mean aggressiveness increases over the course of an epidemic. These results support the idea that alloinoculum contributes to the carryover of epidemics between winter and spring crops and that the most aggressive isolates are selected as an epidemic progresses. Ascochyta blight, caused by Didymella pinodes, is responsible for severe losses in pea crops. While previous studies have shown that ascochyta blight epidemics on winter and spring crops are due to a single population of D. pinodes, suggesting that isolates from the two crops present similar pathogenicity characteristics, that hypothesis have never been tested. Genetic analysis of subpopulations sampled throughout a growing season from winter and spring pea plots revealed high genetic diversity within subpopulations, whereas pathogenicity tests showed that mean aggressiveness increases over the course of an epidemic. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  19. A Winter's View of a Gullied Crater

    NASA Image and Video Library

    2017-04-18

    This image from NASA's Mars Reconnaissance Orbiter (MRO) shows the location with the most impressive known gully activity in Mars' northern hemisphere. Gullies are active in the winter due to carbon dioxide frost, but northern winters are shorter and warmer than southern winters, so there is less frost and less gully activity.. https://photojournal.jpl.nasa.gov/catalog/PIA21593

  20. Predictable climate dynamics of abnormal East Asian winter monsoon: once-in-a-century snowstorms in 2007/2008 winter

    NASA Astrophysics Data System (ADS)

    Wu, Zhiwei; Li, Jianping; Jiang, Zhihong; He, Jinhai

    2011-10-01

    In 2008 (January-February), East Asia (EA) experiences the most severe and long-persisting snowstorm in the past 100 years. Results in this study show that 2007/2008 winter is dominant by the third principal mode of the East Asian winter monsoon (EAWM) which explains 8.7% of the total surface air temperature variance over EA. Significantly distinguished from the first two leading modes, the third mode positive phase features an increased surface pressure over the northwestern EA, an enhanced central Siberian high (CSH), a strengthened and northwestward extended western Pacific subtropical high (WPSH) and anomalously strong moisture transport from western Pacific, Arabian Sea and Bay of Bengal to EA. It also exhibits an intimate linkage with the sea surface temperature anomalies (SSTAs) in the Arctic Ocean areas adjacent to northern Eurasian continent, central North Pacific and northeastern Pacific. Such SSTAs emerge in prior autumn and persist through ensuing winter, signifying precursory conditions for the anomalous third EAWM mode. Numerical experiments with a simple general circulation model demonstrate that the Arctic SSTAs excite geo-potential height anomalies over northern Eurasian continent and impacts on the CSH, while the extra-tropical Pacific SSTAs deform the WPSH. Co-effects of them play crucial roles on origins of the third EAWM mode. Based on these results, an empirical model is established to predict the third mode of the EAWM. Hindcast is performed for the 1957-2008 period, which shows a quite realistic prediction skill in general and good prediction ability in the extreme phase of the third mode of the EAWM such as 2007/2008 winter. Since all these predictors can be readily monitored in real time, this empirical model provides a real time forecast tool and may facilitate the seasonal prediction of high-impact weather associated with the abnormal EAWM.

  1. 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. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Different adaptations of Chinese winter-over expeditioners during prolonged Antarctic and sub-Antarctic residence.

    PubMed

    Chen, Nan; Wu, Quan; Li, Hao; Zhang, Tao; Xu, Chengli

    2016-05-01

    Prolonged residence in Antarctica is characterized by exposure to isolated, confined, and extreme (ICE) environment. Winter-over expeditioners at research stations often exhibit a complex of psychophysiological symptoms, which varied by stations and sociocultural backgrounds. To understand the different patterns of psychophysiological responses provoked by environmental stress, we conducted a longitudinal assessment of mood and endocrine function in two groups of Chinese expeditioners who were deployed to sub-Antarctic (Great Wall Station, 62°S, N = 12) and Antarctic (Zhongshan Station, 66°S, N = 16) from December 2003 to 2005. Measures of mood, thyroid function, the levels of plasma catecholamine, and circulating interleukins were obtained at departure from China, mid-winter (Antarctica), end of winter (Antarctica), and return to China, respectively. The Zhongshan Station crew experienced significant increases in fatigue, anger, tension, confusion, and decrease in free thyroxine (FT4), norepinephrine (NE), and epinephrine (E) during the winter, increase in thyrotropin (TSH) and total triiodothyronine (TT3) when returning, whereas their counterparts at Great Wall Station only experienced increased TT3 after deployment. Moreover, compared with the Great Wall Station crew, the Zhongshan Station crew exhibited greater increase in anger, greater decrease in FT4, total thyroxine (TT4), NE and E over the winter, and greater increase in TSH when returning. Chinese expeditioners who lived and worked at the Antarctic station and the sub-Antarctic station for over a year showed different change patterns in mood and endocrine hormones. Negative mood and endocrine dysfunction were positively associated with the severity of environment. The study is a supplement to scientific knowledge on psychophysiological variation under ICE environment, which has certain applied value for the development of preventive countermeasures or interventions.

  3. Different adaptations of Chinese winter-over expeditioners during prolonged Antarctic and sub-Antarctic residence

    NASA Astrophysics Data System (ADS)

    Chen, Nan; Wu, Quan; Li, Hao; Zhang, Tao; Xu, Chengli

    2016-05-01

    Prolonged residence in Antarctica is characterized by exposure to isolated, confined, and extreme (ICE) environment. Winter-over expeditioners at research stations often exhibit a complex of psychophysiological symptoms, which varied by stations and sociocultural backgrounds. To understand the different patterns of psychophysiological responses provoked by environmental stress, we conducted a longitudinal assessment of mood and endocrine function in two groups of Chinese expeditioners who were deployed to sub-Antarctic (Great Wall Station, 62°S, N = 12) and Antarctic (Zhongshan Station, 66°S, N = 16) from December 2003 to 2005. Measures of mood, thyroid function, the levels of plasma catecholamine, and circulating interleukins were obtained at departure from China, mid-winter (Antarctica), end of winter (Antarctica), and return to China, respectively. The Zhongshan Station crew experienced significant increases in fatigue, anger, tension, confusion, and decrease in free thyroxine (FT4), norepinephrine (NE), and epinephrine (E) during the winter, increase in thyrotropin (TSH) and total triiodothyronine (TT3) when returning, whereas their counterparts at Great Wall Station only experienced increased TT3 after deployment. Moreover, compared with the Great Wall Station crew, the Zhongshan Station crew exhibited greater increase in anger, greater decrease in FT4, total thyroxine (TT4), NE and E over the winter, and greater increase in TSH when returning. Chinese expeditioners who lived and worked at the Antarctic station and the sub-Antarctic station for over a year showed different change patterns in mood and endocrine hormones. Negative mood and endocrine dysfunction were positively associated with the severity of environment. The study is a supplement to scientific knowledge on psychophysiological variation under ICE environment, which has certain applied value for the development of preventive countermeasures or interventions.

  4. 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.

  5. 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.

  6. Global climate change and reindeer: effects of winter weather on the autumn weight and growth of calves.

    PubMed

    Weladji, Robert B; Holand, Øystein

    2003-07-01

    Reindeer/caribou (Rangifer tarandus), which constitute a biological resource of vital importance for the physical and cultural survival of Arctic residents, and inhabit extremely seasonal environments, have received little attention in the global change debate. We investigated how body weight and growth rate of reindeer calves were affected by large-scale climatic variability [measured by the North Atlantic Oscillation (NAO) winter index] and density in one population in central Norway. Body weights of calves in summer and early winter, as well as their growth rate (summer to early winter), were significantly influenced by density and the NAO index when cohorts were in utero. Males were heavier and had higher absolute growth than females, but there was no evidence that preweaning condition of male and female calves were influenced differently by the NAO winter index. Increasing NAO index had a negative effect on calves' body weight and growth rate. Increasing density significantly reduced body weight and growth rate of calves, and accentuated the effect of the NAO winter index. Winters with a higher NAO index are thus severe for reindeer calves in this area and their effects are associated with nutritional stress experienced by the dams during pregnancy or immediately after calving. Moreover, increased density may enhance intra-specific competition and limits food available at the individual level within cohorts. We conclude that if the current pattern of global warming continues, with greater change occurring in northern latitudes and during winter as is predicted, reduced body weight of reindeer calves may be a consequence in areas where winters with a high NAO index are severe. This will likely have an effect on the livelihood of many northern indigenous peoples, both economically and culturally.

  7. 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.

  8. The Unusual Southern Hemisphere Stratosphere Winter of 2002

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.

    2003-01-01

    The southern hemisphere stratospheric winter of 2002 was the most unusual winter yet observed in the southern hemisphere climate record. Temperatures near the edge of the Antarctic polar vortex were considerably warmer than normal over the entire course of the winter. The polar night jet was considerably weaker than normal, and was displaced more poleward than has been observed in previous winters. These record high temperatures and weak jet resulted from a series of wave events that took place over the course of the winter. The first large event occurred on 15 May, and the final warming occurred on 25 October. The propagation of these wave events from the troposphere is diagnosed from time series of Eliassen-Palm flux vectors. The wave events tended to occur irregularly over the course of the winter, and pre-conditioned the polar night jet for the extremely large wave event of 22 September. This large wave event resulted in the first ever observed major stratospheric warming in the southern hemisphere. This wave event split the Antarctic ozone hole. The combined effect of the wave events of the 2002 winter resulted in the smallest ozone hole observed since 1988.

  9. Sage-grouse habitat selection during winter in Alberta

    USGS Publications Warehouse

    Carpenter, Jennifer L.; Aldridge, Cameron L.; Boyce, Mark S.

    2010-01-01

    Greater sage-grouse (Centrocercus urophasianus) are dependent on sagebrush (Artemisia spp.) for food and shelter during winter, yet few studies have assessed winter habitat selection, particularly at scales applicable to conservation planning. Small changes to availability of winter habitats have caused drastic reductions in some sage-grouse populations. We modeled winter habitat selection by sage-grouse in Alberta, Canada, by using a resource selection function. Our purpose was to 1) generate a robust winter habitat-selection model for Alberta sage-grouse; 2) spatially depict habitat suitability in a Geographic Information System to identify areas with a high probability of selection and thus, conservation importance; and 3) assess the relative influence of human development, including oil and gas wells, in landscape models of winter habitat selection. Terrain and vegetation characteristics, sagebrush cover, anthropogenic landscape features, and energy development were important in top Akaike's Information Criterionselected models. During winter, sage-grouse selected dense sagebrush cover and homogenous less rugged areas, and avoided energy development and 2-track truck trails. Sage-grouse avoidance of energy development highlights the need for comprehensive management strategies that maintain suitable habitats across all seasons. ?? 2010 The Wildlife Society.

  10. 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

  11. Patterns of leaf morphology and leaf N content in relation to winter temperatures in three evergreen tree species

    NASA Astrophysics Data System (ADS)

    Mediavilla, Sonia; Gallardo-López, Victoria; González-Zurdo, Patricia; Escudero, Alfonso

    2012-09-01

    The competitive equilibrium between deciduous and perennial species in a new scenario of climate change may depend closely on the productivity of leaves along the different seasons of the year and on the morphological and chemical adaptations required for leaf survival during the different seasons. The aim of the present work was to analyze such adaptations in the leaves of three evergreen species ( Quercus ilex, Q. suber and Pinus pinaster) and their responses to between-site differences in the intensity of winter harshness. We explore the hypothesis that the harshness of winter would contribute to enhancing the leaf traits that allow them to persist under conditions of stress. The results revealed that as winter harshness increases a decrease in leaf size occurs in all three species, together with an increase in the content of nitrogen per unit leaf area and a greater leaf mass per unit area, which seems to be achieved only through increased thickness, with no associated changes in density. P. pinaster was the species with the most intense response to the harshening of winter conditions, undergoing a more marked thickening of its needles than the two Quercus species. Our findings thus suggest that lower winter temperatures involve an increase in the cost of leaf production of evergreen species, which must be taken into account in the estimation of the final cost and benefit balance of evergreens. Such cost increases would be more pronounced for those species that, like P. pinaster, show a stronger response to the winter cold.

  12. 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%.

  13. Variability and Change in Seasonal Water Storage in the Major Arctic Draining Eurasian River Systems

    NASA Astrophysics Data System (ADS)

    Serreze, M. C.; Barrett, A. P.

    2015-12-01

    Variability and change in seasonal water storage in the major Arctic-draining watersheds of Eurasia (Ob. Yenisei and Lena) are assessed in several ways using a combination of storage estimates from the NASA GRACE satellite system, gauged runoff and output from the NASA MERRA atmospheric reanalysis. The study is motivated by the pronounced environmental changes observed in the northern high latitudes and recognition of the climatic importance of changes in hydrology both within and beyond the region. Monthly storage changes based on GRACE gravimetric measurements (2002-2015) and from a water balance approach for the same period calculating storage changes as a residual using gauged runoff along with aerologically-determined net precipitation (atmospheric vapor flux convergence minus the time change in atmospheric precipitable water) from MERRA are generally in good agreement. Agreement is also good for calculations in which aerologically-determined net precipitation is replaced with the MERRA forecasts of precipitation and evapotranspiration. On average, the storage in each of the three watersheds examined (the Ob, Yenisei and Lena) peaks in March and is at a minimum in September. However, this seasonal cycle, primarily driven by snowpack storage through autumn and winter, and snowmelt through spring and summer, varies considerably from year to year in amplitude, phase and between the three watersheds in response to variability in precipitation, evapotranspiration, and near surface air temperature. As assessed over the longer period 1979-2015 covered by MERRA, there is evidence that in response to rising air temperatures influencing precipitation phase and snow storage, peak storage has shifted to earlier in the winter. While recent work provides evidence for a link between increased autumn snowfall over Eurasia and reduced autumn sea ice extent that provides for a moisture source, the effect of increased snowfall is not clearly apparent in water storage.

  14. The relationship of blue crab abundance to winter mortality of Whooping Cranes

    USGS Publications Warehouse

    Pugesek, Bruce H.; Baldwin, Michael J.; Stehn, Thomas

    2013-01-01

    We sampled blue crab (Callinectes sapidus) numbers in marshes on the Aransas National Wildlife Refuge, Texas from 1998-2006, while simultaneously censusing the wintering population of Whooping Cranes (Grus americana) on the refuge and surrounding habitats. This was done to determine whether mortality of wintering Whooping Cranes was related to the availability of this food source. Yearly variation in crab numbers was high, ranging from a low of 0.1 crabs to a high of 3.4 crabs per 100-m transect section. Significant non-linear increases in both juvenile and adult mortality in relation to decreasing crab abundance was observed. Results suggest that some threshold of crab abundance exists in which Whooping Cranes have higher survival on their wintering grounds.

  15. What Is a Mild Winter? Regional Differences in Within-Species Responses to Climate Change.

    PubMed

    Vetter, Sebastian G; Ruf, Thomas; Bieber, Claudia; Arnold, Walter

    2015-01-01

    Climate change is known to affect ecosystems globally, but our knowledge of its impact on large and widespread mammals, and possibly population-specific responses is still sparse. We investigated large-scale and long-term effects of climate change on local population dynamics using the wild boar (Sus scrofa L.) as a model species. Our results show that population increases across Europe are strongly associated with increasingly mild winters, yet with region-specific threshold temperatures for the onset of exponential growth. Additionally, we found that abundant availability of critical food resources, e.g. beech nuts, can outweigh the negative effects of cold winters on population growth of wild boar. Availability of beech nuts is highly variable and highest in years of beech mast which increased in frequency since 1980, according to our data. We conclude that climate change drives population growth of wild boar directly by relaxing the negative effect of cold winters on survival and reproduction, and indirectly by increasing food availability. However, region-specific responses need to be considered in order to fully understand a species' demographic response to climate change.

  16. 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

  17. Lake Stability and Winter-Spring Transitions: Decoupled Ice Duration and Winter Stratification

    NASA Astrophysics Data System (ADS)

    Daly, J.; Dana, S.; Neal, B.

    2016-12-01

    Ice-out is an important historical record demonstrating the impact of warmer air temperatures on lake ice. To better understand regional differences in ice-out trends, to characterize the thermal dynamics of smaller mountain lakes, and to develop baseline data for Maine's high elevations landscapes, sub-hourly water temperatures have been collected in over a dozen of Maine's mountain lakes since 2010. Both surface water and hypolimnion temperature data are recorded year-round, facilitating the determination of ice-in, ice-out, and the duration of winter stratification. The multi-year record from sites across as 250 km transect allows us to compare spatial variability related to lake morphometry and location with inter-annual variability related to local weather. All of the study lakes are large enough to stratify during the summer and mix extensively during the fall. Most years, our data show that the onset of winter stratification is nearly synchronous across the study area and is associated with cold air temperatures. Winter stratification can begin days to weeks before ice-in; the timing of ice-in shows more variability, with both elevation and basin aspect influencing the timing. Ice-out shows both the anticipated spatial and interannual variability; some years there is strong coherence between locations while other years show high variability, possibly a function of differences in snowpack. Ice-out is not always immediately followed by the end of winter stratification, there is sometimes a lag of days to weeks before the lakes mix. If the warm temperatures that lead to ice-out are followed by calm days without significant wind, the surface of some lakes begins to warm quickly maintaining the density difference and prolonging winter stratification. The longer the lag time, the stronger the density difference becomes which may also result in a very brief period of mixing in the spring prior to set-up of summer stratification. This year's El Niño event resulted

  18. 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, innertubing...

  19. 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.

  20. 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…

  1. Responses of High-Elevation Cold Desert Shrubs to a Wet Winter After California's Historic Drought of 2012 - 2015.

    NASA Astrophysics Data System (ADS)

    Loik, M. E.

    2016-12-01

    California experienced an historic drought between 2011 and late 2015, which caused lasting impacts on plant survival and productivity, community patterns, and ecosystem processes. The winter of 2015-2016 was relatively wet by comparison, with over twice the annual snowfall and total precipitation (479 mm) as during the drought years. This study compared soil water content, water potential, photosynthetic processes, and Net Primary Productivity (NPP) for the widespread, co-dominant shrubs Artemisia tridentata (Asteraceae) and Purshia tridentata (Rosaceae) at the ecotone with Sierra Nevada conifer forest in eastern California (2315 m). Measurements were made in June and July 2014, 2015, and 2016, during the seasonal peak of new leaf, stem, and flower production. Soil water content was twice as high in early summer 2016 compared to 2014 and 2015. Mid-morning stem water potential averaged -1.80 MPa in 2014 and increased to -1.20 MPa in 2016 for A. tridentata; water potential for P. tridentata increased from -2.20 MPa to -1.30 MPa over the same period. Stomatal conductance to water vapor (gs) averaged 0.285 mol m-2 s-1 during the drought and increased almost 3-fold by 2016 for A. tridentata. By contrast, gs for P. tridentata increased by 1.6-fold from dry to wet years. Mean photosynthetic CO2 assimilation (A) was 32 μmol m-2 s-1 in the wet year 2016 for A. tridentata, which was almost twice that during the drought. The change in A was much smaller from wet to dry years for P. tridentata. The A vs. gs response wasmore sensitive to drought for A. tridentata than for P. tridentata. For both species, stomata closed around 11:30 h local time during the drought, but stayed open for the entire daytime during June and July of 2016. NPP was about two-fold greater in 2016 than in 2015 for A. tridentata, but only about 15% greater for P. tridentata over the same time. Results indicate that A. tridentata is capable of appreciable upregulation of photosynthesis and productivity in

  2. Use of mini-refuges by female northern pintails wintering in southwestern Louisiana

    USGS Publications Warehouse

    Cox, Robert R.; Afton, Alan D.

    1998-01-01

    The Gulf Coast Joint Venture of the North American Waterfowl Management Plan began contracting private agricultural lands (hereafter mini-refuges) in 1988 to expand existing sanctuaries for northern pintails (Anas acuta) in southwestern Louisiana. Previous research suggested that mini-refuges may prove more attractive to pintails than permanent, open-water pools (pools) on refuges because mini-refuges provide sanctuary and food during the day, whereas pools generally provide only sanctuary (Rave and Cordes 1993). We used radiotelemetry to compare diel use of mini-refuges and pools (Lacassine Pool and Amoco Pool) by female pintails in southwestern Louisiana during winters of 1991-1992 and 1992-1993. We examined variation in use of these areas in relation to female age (immature or adult), time period (prehunting season, first hunting season, time between split hunting seasons, second hunting season, and posthunting season), and winter (1991-1992 and 1992-1993). Diurnal use of min-refuges and pools differed among time periods, but differences were not consistent between winters. Mini-refuges accounted for <2% of diurnal use by pintails in 7 of 10 time-period and winter comparisons. Diurnal use of mini-refuges was lower than that of Lacassine Pool in 8 of 10 time-period and winter comparisons. Diurnal use of mini-refuges was lower than tha of Amoco pool during first hunting season in 1992-1993, but use of these areas did not differ within other time periods and winters. Nocturnal use of mini-refuges and pools did not differ in relation to female age, time period, winter, or individual bird. Nocturnal use of mini-refuges did not differ from that of Lacassine Pool. In contrast to predictions and findings by Rave and Cordes (1993), we found that: (1) female pintails did not use mini-refuges more than pools, and (2) female pintails used mini-refuges at night. We believe that use of mini-refuges by pintails could be increased if mini-refuges were (1) located in areas of

  3. Chapter 7: Migration and winter ecology

    Treesearch

    Deborah M. Finch; Jeffrey F. Kelly; Jean-Luc E. Cartron

    2000-01-01

    The willow flycatcher (Empidonax traillii) is a Neotropical migrant that breeds in North America, but winters in Central and northern South America. Little specific information is known about migration and wintering ecology of the southwestern willow flycatcher (E. t. extimus) (Yong and Finch 1997). Our report applies principally...

  4. Registration of USDA-UTWH-102 winter hardy orchardgrass germplasm

    USDA-ARS?s Scientific Manuscript database

    The USDA-ARS announces the release of USDA-UTWG-102 orchardgrass (Dactylis glomerata L.) (Reg. No., PI) germplasm. USDA-UTWH-102 possesses increased winter hardiness and provides utility to applied orchardgrass breeding and genetic programs. USDA-UTWH-102 is a 24 clone synthetic derived from orchard...

  5. Past and future hydro-climatic change and the 2015 drought in the interior of western Canada

    NASA Astrophysics Data System (ADS)

    DeBeer, C. M.; Wheater, H. S.; Pomeroy, J. W.; Stewart, R. E.; Szeto, K.; Brimelow, J.; Chun, K. P.; Masud, M. B.; Bonsal, B. R.

    2015-12-01

    The interior of western Canada has experienced rapid and severe hydro-climatic change in recent decades. This is projected to continue in future. Since 1950, mean annual air temperature has increased by 2 °C (4 °C increase in winter daily means) with associated changes in cryospheric regime. Changes in precipitation have varied regionally; in the Prairies there has been a decrease in winter precipitation, shift from snowfall to rainfall, and increased clustering of summer rainfall events into multiple day storms. Regionally, river discharge indicates an earlier spring freshet and increased incidence of rain-on-snow peak flow events, but otherwise mixed responses due to multiple process interactions. In winter/spring 2015, persistent anomalous ridging conditions developed over western North America causing widespread drought. This produced abnormally warm and dry conditions over the Rocky Mountain headwaters of the Mackenzie and Saskatchewan Rivers, resulting in low spring snowpacks that melted earlier than normal and were followed by an atypical lack of spring rainfall. By summer 2015, most of western Canada was subject to extreme drought conditions leading to record dry soil moisture conditions in parts of the Prairies during a key crop growth time, streamflows that were greatly diminished, and extensive wildfires across the Boreal Forest. The importance of the warmer winter to this drought and the contextual trend for increasing winter warmth provide new insight into the impact of climate warming on droughts in cold regions. This talk will discuss efforts by the Changing Cold Regions Network (CCRN; www.ccrnetwork.ca) to understand and diagnose the 2015 drought, its potential linkages with the concurrent California drought and other continental events, and its relevance in the context of historical and predicted future climate change.

  6. Home advantage in the Winter Paralympic Games 1976-2014.

    PubMed

    Wilson, Darryl; Ramchandani, Girish

    2017-01-01

    There is a limited amount of home advantage research concerned with winter sports. There is also a distinct lack of studies that investigate home advantage in the context of para sport events. This paper addresses this gap in the knowledge by examining home advantage in the Winter Paralympic Games. Using a standardised measure of success, we compared the performances of host nations at home with their own performances away from home between 1976 and 2014. Both country level and individual sport level analysis is conducted for this time period. Comparisons are also drawn with the Winter Olympic Games since 1992, the point from which both the Winter Olympic Games and the Winter Paralympic Games have been hosted by the same nations and in the same years. Clear evidence of a home advantage effect in the Winter Paralympic Games was found at country level. When examining individual sports, only alpine skiing and cross country skiing returned a significant home advantage effect. When comparing home advantage in the Winter Paralympic Games with the Winter Olympic Games for the last seven host nations (1992-2014), we found that home advantage was generally more pronounced (although not a statistically significant difference) in the case of the former. The causes of home advantage in the Winter Paralympic Games are unclear and should be investigated further.

  7. Tree-Ring Dating of Extreme Lake Levels at the Subarctic?Boreal Interface

    NASA Astrophysics Data System (ADS)

    Bégin, Yves

    2001-03-01

    The dates of extreme water levels of two large lakes in northern Quebec have been recorded over the last century by ice scars on shoreline trees and sequences of reaction wood in shore trees tilted by wave erosion. Ice-scar chronologies indicate high water levels in spring, whereas tree-tilting by waves is caused by summer high waters. A major increase in both the amplitude and frequency of ice floods occurred in the 1930s. No such change was indicated by the tree-tilting chronologies, but wave erosion occurred in exceptionally rainy years. According to the modern record, spring lake-level rise is due to increased snowfalls since the 1930s. However, the absence of erosional marks in a large number of years since 1930 suggests a high frequency of low-water-level years resulting from dry conditions. Intercalary years with very large numbers of marked trees (e.g., 1935) indicate that the interannual range of summer lake levels has increased since the 1930s. Increased lake-flood frequency is postulated to be related to a slower expansion of arctic anticyclones, favoring the passage of cyclonic air masses over the area and resulting in abundant snowfall in early winter. Conditions in summer are due to the rate of weakening of the anticyclones controlling the position of the arctic front in summer. This position influences the path of the cyclonic air masses, which control summer precipitation and, consequently, summer lake levels in the area.

  8. Hibernation in an antarctic fish: on ice for winter.

    PubMed

    Campbell, Hamish A; Fraser, Keiron P P; Bishop, Charles M; Peck, Lloyd S; Egginton, Stuart

    2008-03-05

    Active metabolic suppression in anticipation of winter conditions has been demonstrated in species of mammals, birds, reptiles and amphibians, but not fish. This is because the reduction in metabolic rate in fish is directly proportional to the decrease in water temperature and they appear to be incapable of further suppressing their metabolic rate independently of temperature. However, the Antarctic fish (Notothenia coriiceps) is unusual because it undergoes winter metabolic suppression irrespective of water temperature. We assessed the seasonal ecological strategy by monitoring swimming activity, growth, feeding and heart rate (f(H)) in N. coriiceps as they free-ranged within sub-zero waters. The metabolic rate of wild fish was extrapolated from f(H )recordings, from oxygen consumption calibrations established in the laboratory prior to fish release. Throughout the summer months N. coriiceps spent a considerable proportion of its time foraging, resulting in a growth rate (G(w)) of 0.18 +/- 0.2% day(-1). In contrast, during winter much of the time was spent sedentary within a refuge and fish showed a net loss in G(w) (-0.05 +/- 0.05% day(-1)). Whilst inactive during winter, N. coriiceps displayed a very low f(H), reduced sensory and motor capabilities, and standard metabolic rate was one third lower than in summer. In a similar manner to other hibernating species, dormancy was interrupted with periodic arousals. These arousals, which lasted a few hours, occurred every 4-12 days. During arousal activity, f(H) and metabolism increased to summer levels. This endogenous suppression and activation of metabolic processes, independent of body temperature, demonstrates that N. coriiceps were effectively 'putting themselves on ice' during winter months until food resources improved. This study demonstrates that at least some fish species can enter a dormant state similar to hibernation that is not temperature driven and presumably provides seasonal energetic benefits.

  9. Winter precipitation change in South China in recent decades

    NASA Astrophysics Data System (ADS)

    Cai, Jingning

    2013-04-01

    Precipitation change is one of important climate researches in China, but winter precipitation variation in South China has not been studied so frequently. In China, it is rainy when hot; so summer precipitation is usually one focus in research, esp. in South China. However, winter precipitation and its change influence people profoundly in South China, also. The most recent example is what happened over South China in winter 2008. In this winter, millions of people suffered from the unusual cold and snowy winter. It led to huge loss in economy and traffic as well. Roads closed and railway stations were jammed and crowded with people; many planes were grounded for heavy snow and bad weather. Transmission lines faulted in the mountains. The ommunication signals were affected. Everyday food supply including vegetables and meats had to be delayed or interrupted. In some city even water supply was interrupted. And garbage in the city was piled up. Just in this winter the snow depth and coverage area in many places in South China broke or equaled the historical records. In fact, it isn't the only one unusual winter precipitation event in South China. Since 1950s, several freezing and snowy winters struck the South in China. In this research, winter precipitation change in recent years in South China has been discussed based on the precipitation observations. The associated large scale atmospheric circulation change is also analyzed. It is found that snowy winter in South China hardly comes in most periods of 2000s, but in recent decades this heavy snow in winter has appeared several times as observations shows. This phenomenon could be related to the large scale atmospheric circulation change.

  10. Distribution and diurnal behavior of Steller's Eiders wintering on the Alaska Peninsula

    USGS Publications Warehouse

    Laubhan, M.K.; Metzner, K.A.

    1999-01-01

    We studied the distribution and activities of adult Steller's Eiders (Polysticta stelleri) during winter and spring on a deep-water embayment and a shallow lagoon along the Alaska Peninsula from September 1980 to May 1981. During the remigial molt, eiders were observed on Izembek Lagoon but not on Cold Bay. Following the flightless period, Izembek Lagoon continued to support 63-100% of eiders encountered during surveys. As ice cover on Izembek Lagoon increased, the number of birds decreased on Izembek Lagoon but increased on Cold Bay, suggesting that some eiders disperse to nearshore, deep-water habitats in close proximity to Izembek Lagoon during severe weather. Diurnal activity budgets indicated that the amount of time resting or engaged in aggression and alert activities was similar among locations, seasons, tidal stages, and sexes. In contrast, time spent foraging differed among seasons and locations but did not differ among tidal stages or sexes. Although time spent foraging was similar during winter and spring on Izembek Lagoon, eiders on Cold Bay foraged more during winter compared to spring. Synchronous diving was the dominant foraging strategy.

  11. East Asia winter climate changes under RCP scenarios in terms of East Asian winter monsoon indices

    NASA Astrophysics Data System (ADS)

    Ahn, J. B.; Hong, J. Y.

    2016-12-01

    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 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°C to 5°C under RCP4.5 and from 3°C 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 that the interannual variability of the indices will be maintained with intensity similar to that of the present. AcknowledgmentsThis work was carried out with the support of

  12. Warmed Winter Water Temperatures Alter Reproduction in Two Fish Species

    NASA Astrophysics Data System (ADS)

    Firkus, Tyler; Rahel, Frank J.; Bergman, Harold L.; Cherrington, Brian D.

    2018-02-01

    We examined the spawning success of Fathead Minnows ( Pimephales promelas) and Johnny Darters ( Etheostoma nigrum) exposed to elevated winter water temperatures typical of streams characterized by anthropogenic thermal inputs. When Fathead Minnows were exposed to temperature treatments of 12, 16, or 20 °C during the winter, spawning occurred at 16 and 20 °C but not 12 °C. Eggs were deposited over 9 weeks before winter spawning ceased. Fathead Minnows from the three winter temperature treatments were then exposed to a simulated spring transition. Spawning occurred at all three temperature treatments during the spring, but fish from the 16° and 20 °C treatment had delayed egg production indicating a latent effect of warm winter temperatures on spring spawning. mRNA analysis of the egg yolk protein vitellogenin showed elevated expression in female Fathead Minnows at 16 and 20 °C during winter spawning that decreased after winter spawning ceased, whereas Fathead Minnows at 12 °C maintained comparatively low expression during winter. Johnny Darters were exposed to 4 °C to represent winter temperatures in the absence of thermal inputs, and 12, 16, and 20 °C to represent varying degrees of winter thermal pollution. Johnny Darters spawned during winter at 12, 16, and 20 °C but not at 4 °C. Johnny Darters at 4 °C subsequently spawned following a simulated spring period while those at 12, 16, and 20 °C did not. Our results indicate elevated winter water temperatures common in effluent-dominated streams can promote out-of-season spawning and that vitellogenin expression is a useful indicator of spawning readiness for fish exposed to elevated winter temperatures.

  13. Impacts of winter NPO on subsequent winter ENSO: sensitivity to the definition of NPO index

    NASA Astrophysics Data System (ADS)

    Chen, Shangfeng; Wu, Renguang

    2018-01-01

    This study investigates the linkage between boreal winter North Pacific Oscillation (NPO) and subsequent winter El Niño-Southern Oscillation (ENSO) based on seven different NPO indices. Results show that the influence of winter NPO on the subsequent winter El Niño is sensitive to how the NPO is defined. A significant NPO-El Niño connection is obtained when the NPO-related anomalous cyclone over the subtropical North Pacific extends to near-equatorial regions. The anomalous cyclone induces warm sea surface temperature (SST) anomalies through modulating surface heat fluxes. These warm SST anomalies are able to maintain into the following spring and summer through an air-sea coupled process and in turn induce significant westerly wind anomalies over the tropical western Pacific. In contrast, the NPO-El Niño relationship is unclear when the NPO-related anomalous cyclone over the subtropical North Pacific is confined to off-equatorial regions and cannot induce significant warm SST anomalies over the subtropical North Pacific. The present study suggests that definitions of NPO should be taken into account when using NPO to predict ENSO. In particular, we recommend defining the NPO index based on the empirical orthogonal function technique over appropriate region that does not extend too far north.

  14. Diet and gut morphology of male mallards during winter in North Dakota

    USGS Publications Warehouse

    Olsen, R.E.; Cox, R.R.; Afton, A.D.; Ankney, C.D.

    2011-01-01

    A free-ranging Mallard (Anas platyrhynchos) population was investigated during winter (December-January 1996-1999) below the Garrison Dam, North Dakota, USA, to relate diet to gut morphology variation in males. Four explanatory variables (fish consumption, male age, winter, and body size) were evaluated as to whether they influenced five response variables associated with gut characteristics of Mallards. Response variables were lower gastro-intestinal tract mass (LGIT), dry liver mass, dry gizzard mass, small intestine length, and ceca length. Diets of Mallards were comprised primarily of Rainbow Smelt (Osmerus mordax) and concomitantly variation in gizzard mass was small. LGIT mass of juveniles was larger than that of adults, greater for those that consumed fish, and greater during the coldest and snowiest winter. Liver mass and small intestine length of Mallards that consumed fish were greater than those that did not. Mallards may maintain lengthy intestines to increase digestive efficiency. Gut size variation was not entirely attributable to dietary composition but also influenced by body size and environmental conditions such that over-winter survival is maximized.

  15. Anaerobic digestion of spring and winter wheat: Comparison of net energy yields.

    PubMed

    Rincón, Bárbara; Heaven, Sonia; Salter, Andrew M; Banks, Charles J

    2016-10-14

    Anaerobic digestion of wheat was investigated under batch conditions. The article compares the potential net energy yield between a winter wheat (sown in the autumn) and a spring wheat (sown in the spring) grown in the same year and harvested at the same growth stage in the same farm. The spring wheat had a slightly higher biochemical methane potential and required lower energy inputs in cultivation, but produced a lower dry biomass yield per hectare, which resulted in winter wheat providing the best overall net energy yield. The difference was small; both varieties gave a good net energy yield. Spring sowing may also offer the opportunity for growing an additional over-winter catch crop for spring harvest, thus increasing the overall biomass yield per hectare, with both crops being potential digester feedstocks.

  16. Numerical simulation of a winter hailstorm event over Delhi, India on 17 January 2013

    NASA Astrophysics Data System (ADS)

    Chevuturi, A.; Dimri, A. P.; Gunturu, U. B.

    2014-09-01

    This study analyzes the cause of rare occurrence of winter hailstorm over New Delhi/NCR (National Capital Region), India. The absence of increased surface temperature or low level of moisture incursion during winter cannot generate the deep convection required for sustaining a hailstorm. Consequently, NCR shows very few cases of hailstorms in the months of December-January-February, making the winter hail formation a question of interest. For this study, recent winter hailstorm event on 17 January 2013 (16:00-18:00 UTC) occurring over NCR is investigated. The storm is simulated using Weather Research and Forecasting (WRF) model with Goddard Cumulus Ensemble (GCE) microphysics scheme with two different options, hail or graupel. The aim of the study is to understand and describe the cause of hailstorm event during over NCR with comparative analysis of the two options of GCE microphysics. On evaluating the model simulations, it is observed that hail option shows similar precipitation intensity with TRMM observation than the graupel option and is able to simulate hail precipitation. Using the model simulated output with hail option; detailed investigation on understanding the dynamics of hailstorm is performed. The analysis based on numerical simulation suggests that the deep instability in the atmospheric column led to the formation of hailstones as the cloud formation reached upto the glaciated zone promoting ice nucleation. In winters, such instability conditions rarely form due to low level available potential energy and moisture incursion along with upper level baroclinic instability due to the presence of WD. Such rare positioning is found to be lowering the tropopause with increased temperature gradient, leading to winter hailstorm formation.

  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. 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.

  19. Winter and early spring CO2 efflux from tundra communities of northern Alaska

    USGS Publications Warehouse

    Fahnestock, J.T.; Jones, M.H.; Brooks, P.D.; Walker, D.A.; Welker, J.M.

    1998-01-01

    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. Copyright 1998 by the American Geophysical Union.

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

    PubMed

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

    2015-06-01

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

  1. Evaluation of aerial transects for counting winter mallards

    USGS Publications Warehouse

    Reinecke, K.J.; Brown, M.W.; Nassar, J.R.

    1992-01-01

    Winter waterfowl surveys rarely use sampling methods, and little is known about the precision and biases of their population estimates. Consequently, we developed aerial transect surveys (n=5) in 4 strata comprising 16 substrata in the lower Mississippi Alluvial Valley during winters 1987-88 through 1989-90 to estimate mallard (Anas platyrhynchos) population indices and determine regional patterns of habitat use. Mallard population indices ranged from 1,147,628 (SE=192,341) in December 1988 to 1,790,708 (SE=179,406) in January 1988. Coefficients of variation (CV's) for early winter surveys averaged 0.15 and those for late winter surveys averaged 0.10. During early winter, 59-69% of mallards were on wetlands with water regimes managed for waterfowl; whereas in late winter, 52-79% used wetlands with unmanaged water regimes. Late winter was wet during 1987-88 and 1988-89, and most mallards (62-68%) were on naturally flooded croplands. Use of forested wetlands (3-11%) and moist-soil habitats (3-29%) varied among surveys but was not correlated with water conditions. The number of mallards using naturally flooded croplands (e.g., >1,100,000 in Jan 1988) illustrated the extent of habitat use on private lands. We recommend transect surveys (e.g., 5-yr intervals) for evaluating responses of mallard populations to management programs and as a sampling framework for integrating regional waterfowl research and management data.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  3. Warmed Winter Water Temperatures Alter Reproduction in Two Fish Species.

    PubMed

    Firkus, Tyler; Rahel, Frank J; Bergman, Harold L; Cherrington, Brian D

    2018-02-01

    We examined the spawning success of Fathead Minnows (Pimephales promelas) and Johnny Darters (Etheostoma nigrum) exposed to elevated winter water temperatures typical of streams characterized by anthropogenic thermal inputs. When Fathead Minnows were exposed to temperature treatments of 12, 16, or 20 °C during the winter, spawning occurred at 16 and 20 °C but not 12 °C. Eggs were deposited over 9 weeks before winter spawning ceased. Fathead Minnows from the three winter temperature treatments were then exposed to a simulated spring transition. Spawning occurred at all three temperature treatments during the spring, but fish from the 16° and 20 °C treatment had delayed egg production indicating a latent effect of warm winter temperatures on spring spawning. mRNA analysis of the egg yolk protein vitellogenin showed elevated expression in female Fathead Minnows at 16 and 20 °C during winter spawning that decreased after winter spawning ceased, whereas Fathead Minnows at 12 °C maintained comparatively low expression during winter. Johnny Darters were exposed to 4 °C to represent winter temperatures in the absence of thermal inputs, and 12, 16, and 20 °C to represent varying degrees of winter thermal pollution. Johnny Darters spawned during winter at 12, 16, and 20 °C but not at 4 °C. Johnny Darters at 4 °C subsequently spawned following a simulated spring period while those at 12, 16, and 20 °C did not. Our results indicate elevated winter water temperatures common in effluent-dominated streams can promote out-of-season spawning and that vitellogenin expression is a useful indicator of spawning readiness for fish exposed to elevated winter temperatures.

  4. Physiological processes during winter dormancy and their ecological significance

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

    Havranek, W.M.; Tranquillini, W.

    1995-07-01

    Lengthy and severe winters require that trees in the forests of boreal and mountain zones undergo winter dormancy. Physiologically, a high resistance to subfreezing temperatures and concomitant dehydration are necessary. To accomplish this dormancy, both physiological and structural changes are needed at the cellular level that require induction by endogenous and photoperiodic control early in autumn. Endogenous rhythmicity promotes cold hardening in early autumn and the persistence of hardiness throughout the winter. Numerous physiological functions are maintained at a reduced level, or become completely inhibited during true winter dormancy. Winter hardiness also includes the capability to minimize water loss effectivelymore » when water uptake is severely impeded or impossible. Anatomical features such as tracheids act to minimize xylem embolism during frequent freeze-thaw cycles, and {open_quotes}crown{close_quotes} tissues enable buds to stay in a dehydrated and, thus, more resistant state during winter. Both these structural features are adaptations that contribute to the dominance of conifers in cold climates. Interestingly, deciduous tree species rather than evergreen conifers dominate in the most severe winter climates, although it is not clear whether limitations during winter, during the summer growth period, or during both are most limiting to conifer tree ecology. Additional work that evaluates the importance of winter and summer growth restriction, and their interaction, is needed before a comprehensive understanding of conifer tree ecophysiology will be possible.« less

  5. Winter rye as a bioenergy feedstock: impact of crop maturity on composition, biological solubilization and potential revenue

    DOE PAGES

    Shao, Xiongjun; DiMarco, Kay; Richard, Tom L.; ...

    2015-02-27

    We report that winter annual crops such as winter rye (Secale cereale L) can produce biomass feedstock on seasonally fallow land that continues to provide high-value food and feed from summer annuals such as corn and soybeans. As energy double crops, winter grasses are likely to be harvested while still immature and thus structurally different from the fully senesced plant material typically used for biofuels. This study investigates the dynamic trends in biomass yield, composition, and biological solubilization over the course of a spring harvest season. The water soluble fraction decreased with increasing maturity while total carbohydrate content stayed roughlymore » constant at about 65%. The protein mass fraction decreased with increasing maturity, but was counterbalanced by increasing harvest yield resulting in similar total protein across harvest dates. Winter rye was ground and autoclaved then fermented at 15 g/L total solids by either (1) Clostridium thermocellum or (2) simultaneous saccharification and cofermentation (SSCF) using commercial cellulases (CTec2 and HTec2) and a xylose-fermenting Saccharomyces cerevisiae strain. Solubilization of total carbohydrate dropped significantly as winter rye matured for both C. thermocellum (from approximately 80% to approximately 50%) and SSCF (from approximately 60% to approximately 30%). C. thermocellum achieved total solubilization 33% higher than that of SSCF for the earliest harvest date and 50% higher for the latest harvest date. Potential revenue from protein and bioethanol was stable over a range of different harvest dates, with most of the revenue due to ethanol. In a crop rotation with soybean, recovery of the soluble protein from winter rye could increase per hectare protein production by 20 to 35%. Double-cropping winter rye can produce significant biomass for biofuel production and feed protein as coproduct without competing with the main summer crop. During a 24-day harvest window, the total

  6. Winter rye as a bioenergy feedstock: impact of crop maturity on composition, biological solubilization and potential revenue

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

    Shao, Xiongjun; DiMarco, Kay; Richard, Tom L.

    We report that winter annual crops such as winter rye (Secale cereale L) can produce biomass feedstock on seasonally fallow land that continues to provide high-value food and feed from summer annuals such as corn and soybeans. As energy double crops, winter grasses are likely to be harvested while still immature and thus structurally different from the fully senesced plant material typically used for biofuels. This study investigates the dynamic trends in biomass yield, composition, and biological solubilization over the course of a spring harvest season. The water soluble fraction decreased with increasing maturity while total carbohydrate content stayed roughlymore » constant at about 65%. The protein mass fraction decreased with increasing maturity, but was counterbalanced by increasing harvest yield resulting in similar total protein across harvest dates. Winter rye was ground and autoclaved then fermented at 15 g/L total solids by either (1) Clostridium thermocellum or (2) simultaneous saccharification and cofermentation (SSCF) using commercial cellulases (CTec2 and HTec2) and a xylose-fermenting Saccharomyces cerevisiae strain. Solubilization of total carbohydrate dropped significantly as winter rye matured for both C. thermocellum (from approximately 80% to approximately 50%) and SSCF (from approximately 60% to approximately 30%). C. thermocellum achieved total solubilization 33% higher than that of SSCF for the earliest harvest date and 50% higher for the latest harvest date. Potential revenue from protein and bioethanol was stable over a range of different harvest dates, with most of the revenue due to ethanol. In a crop rotation with soybean, recovery of the soluble protein from winter rye could increase per hectare protein production by 20 to 35%. Double-cropping winter rye can produce significant biomass for biofuel production and feed protein as coproduct without competing with the main summer crop. During a 24-day harvest window, the total

  7. 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,…

  8. 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…

  9. The response of a Kansas winter bird community to weather, photoperiod, and year

    USGS Publications Warehouse

    Stapanian, M.A.; Smith, C.C.; Finck, E.J.

    1999-01-01

    We conducted a bird census along the same route nearly each week for 14 winters (194 censuses), and compared the mean number of species per station and the total number of species recorded on the census with the length of photoperiod and weather variables. We found significant differences among winters for both indicators of species richness. This result is consistent with previous studies in which abundance of food was measured in the same general area. Both indicators of species richness were negatively associated with the number of days after 1 November. This result is consistent with the hypothesis that wintering species dependent on nonrenewed food resources lose individuals to mortality or emigration. Further, there was a positive relationship between photoperiod and both indicators of species richness. This result is consistent with the hypothesis that the detection of individuals in the early morning hours increases with the amount of daylight they have available for foraging and social behaviors. Wind speed and temperature had negative and positive relationships, respectively, to species richness. The number of species per station was greatest on days when the ground was covered with dew and least on days when snow depth was more than 15 cm. When the 'winters' were divided into four 30-day 'quarters', most of the 61 species were recorded with equal frequency in each quarter. Eight species were detected less frequently at the end of winter than in the beginning. Four species exhibited the reverse pattern. Two species were recorded more frequently at the beginning and at the end of the winter than during the middle. Temperature, wind, photoperiod, successive winter day, year, and species-specific evolutionary history all affect winter bird species richness.

  10. 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…

  11. Characteristics of foraging sites and protein status in wintering muskoxen: insights from isotopes of nitrogen

    USGS Publications Warehouse

    Gustine, David D.; Barboza, Perry S.; Lawler, James P.; Arthur, Stephen M.; Shults, Brad S.; Persons, Kate; Adams, Layne 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, β± 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

  12. Climate Response to Negative Greenhouse Gas Radiative Forcing in Polar Winter

    NASA Astrophysics Data System (ADS)

    Flanner, M. G.; Huang, X.; Chen, X.; Krinner, G.

    2018-02-01

    Greenhouse gas (GHG) additions to Earth's atmosphere initially reduce global outgoing longwave radiation, thereby warming the planet. In select environments with temperature inversions, however, increased GHG concentrations can actually increase local outgoing longwave radiation. Negative top of atmosphere and effective radiative forcing (ERF) from this situation give the impression that local surface temperatures could cool in response to GHG increases. Here we consider an extreme scenario in which GHG concentrations are increased only within the warmest layers of winter near-surface inversions of the Arctic and Antarctic. We find, using a fully coupled Earth system model, that the underlying surface warms despite the GHG addition exerting negative ERF and cooling the troposphere in the vicinity of the GHG increase. This unique radiative forcing and thermal response is facilitated by the high stability of the polar winter atmosphere, which inhibit thermal mixing and amplify the impact of surface radiative forcing on surface temperature. These findings also suggest that strategies to exploit negative ERF via injections of short-lived GHGs into inversion layers would likely be unsuccessful in cooling the planetary surface.

  13. 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…

  14. Latitudinal-Related Variation in Wintering Population Trends of Greylag Geese (Anser Anser) along the Atlantic Flyway: A Response to Climate Change?

    PubMed

    Ramo, Cristina; Amat, Juan A; Nilsson, Leif; Schricke, Vincent; Rodríguez-Alonso, Mariano; Gómez-Crespo, Enrique; Jubete, Fernando; Navedo, Juan G; Masero, José A; Palacios, Jesús; Boos, Mathieu; Green, Andy J

    2015-01-01

    The unusually high quality of census data for large waterbirds in Europe facilitates the study of how population change varies across a broad geographical range and relates to global change. The wintering population of the greylag goose Anser anser in the Atlantic flyway spanning between Sweden and Spain has increased from 120 000 to 610 000 individuals over the past three decades, and expanded its wintering range northwards. Although population sizes recorded in January have increased in all seven countries in the wintering range, we found a pronounced northwards latitudinal effect in which the rate of increase is higher at greater latitudes, causing a constant shift in the centre of gravity for the spatial distribution of wintering geese. Local winter temperatures have a strong influence on goose numbers but in a manner that is also dependent on latitude, with the partial effect of temperature (while controlling for the increasing population trend between years) being negative at the south end and positive at the north end of the flyway. Contrary to assumptions in the literature, the expansion of crops exploited by greylag geese has made little contribution to the increases in population size. Only in one case (expansion of winter cereals in Denmark) did we find evidence of an effect of changing land use. The expanding and shifting greylag population is likely to have increasing impacts on habitats in northern Europe during the course of this century.

  15. 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.

  16. Survival of northern pintails banded during winter in North America, 1950-88

    USGS Publications Warehouse

    Hestbeck, J.B.

    1993-01-01

    From 1950 through 1988, the continental breeding population of northern pintails (Anas acuta) varied from 2.0 million to 9.9 million. Because pintails have high fidelity to certain wintering grounds along coasts and large bodies of water, management on these wintering areas may increase population size if changes in winter survival rate are related to changes in population size. I used band-recovery data to estimate survival rates for winter-banded pintails and to test for sex-specific, temporal, and geographic variation in survival rates. Survival rate estimates varied between 0.632 and 0.806 for males, and 0.421 and 0.769 for females. Males had higher (P lt 0.0001) average annual survival rates than females. Limited geographic variation occurred in estimates of average annual survival rates for males, and no variation occurred for females. Males had lower average annual survival rates in the Imperial Valley than in central California (P = 0.007) or in the Gulf Coast (P = 0.092). Little annual variation was found within time periods. However, longer-term variation was found in survival rate estimates for males and females. Males had higher (P = 0.054) average annual survival rates in the Pacific Flyway during 1959-61, a period of drought, breeding-population decline, and restrictive hunting regulations, than during 1950-58, a period with a higher breeding population and liberal regulations. The increase in wintering population size in the Pacific Flyway during the 1970's was associated with a higher average annual survival rate for females in the Pacific Flyway than during the 1950's. Results from the Pacific Flyway suggested that an interaction may exist between population size and the effect of harvest regulations on survival of males. Changes in harvest regulations appeared to have a greater effect at lower population levels.

  17. 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.

  18. Winter in Northern Europe (WINE). The project Winter in Northern Europe (MAP/WINE): Introduction and outlook

    NASA Technical Reports Server (NTRS)

    Vonzahn, U.

    1989-01-01

    The project Winter in Northern Europe (WINE) of the international Middle Atmosphere Program (MAP) comprised a multinational study of the structure, dynamics and composition of the middle atmosphere in winter at high latitudes. Coordinated field measurements were performed during the winter 1983 to 1984 by a large number of ground-based, air-borne, rocket-borne and satellite-borne instruments. Many of the individual experiments were performed in the European sector of the high latitude and polar atmosphere. Studies of the stratosphere, were, in addition, expanded to hemispheric scales by the use of data obtained from remotely sensing satellites. Beyond its direct scientific results, which are reviewed, MAP/WINE has stimulated quite a number of follow-on experiments and projects which address the aeronomy of the middle atmosphere at high and polar latitudes.

  19. Winter chilling speeds spring development of temperate butterflies.

    PubMed

    Stålhandske, Sandra; Gotthard, Karl; Leimar, Olof

    2017-07-01

    Understanding and predicting phenology has become more important with ongoing climate change and has brought about great research efforts in the recent decades. The majority of studies examining spring phenology of insects have focussed on the effects of spring temperatures alone. Here we use citizen-collected observation data to show that winter cold duration, in addition to spring temperature, can affect the spring emergence of butterflies. Using spatial mixed models, we disentangle the effects of climate variables and reveal impacts of both spring and winter conditions for five butterfly species that overwinter as pupae across the UK, with data from 1976 to 2013 and one butterfly species in Sweden, with data from 2001 to 2013. Warmer springs lead to earlier emergence in all species and milder winters lead to statistically significant delays in three of the five investigated species. We also find that the delaying effect of winter warmth has become more pronounced in the last decade, during which time winter durations have become shorter. For one of the studied species, Anthocharis cardamines (orange tip butterfly), we also make use of parameters determined from previous experiments on pupal development to model the spring phenology. Using daily temperatures in the UK and Sweden, we show that recent variation in spring temperature corresponds to 10-15 day changes in emergence time over UK and Sweden, whereas variation in winter duration corresponds to 20 days variation in the south of the UK versus only 3 days in the south of Sweden. In summary, we show that short winters delay phenology. The effect is most prominent in areas with particularly mild winters, emphasising the importance of winter for the response of ectothermic animals to climate change. With climate change, these effects may become even stronger and apply also at higher latitudes. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

  20. Calcium addition at the Hubbard Brook Experimental Forest reduced winter injury to red spruce in a high-injury year

    Treesearch

    Gary J. Hawley; Paul G. Schaberg; Christopher Eagar; Catherine H. Borer

    2006-01-01

    Laboratory experiments have verified that acid-deposition-induced calcium (Ca) leaching reduces the foliar cold tolerance of red spruce (Picea rubens Sarg.) current-year foliage, increasing the risk of winter injury and crown deterioration. However, to date no studies have shown that ambient losses in soil Ca have resulted in increased winter injury...

  1. Reproduction of Meloidogyne incognita on Winter Cover Crops Used in Cotton Production

    PubMed Central

    Timper, Patricia; Davis, Richard F.; Tillman, P. Glynn

    2006-01-01

    Substantial reproduction of Meloidogyne incognita on winter cover crops may lead to damaging populations in a subsequent cotton (Gossypium hirsutum) crop. The amount of population increase during the winter depends on soil temperature and the host status of the cover crop. Our objectives were to quantify M. incognita race 3 reproduction on rye (Secale cereale) and several leguminous cover crops and to determine if these cover crops increase population densities of M. incognita and subsequent damage to cotton. The cover crops tested were ‘Bigbee’ berseem clover (Trifolium alexandrinum), ‘Paradana’ balansa clover (T. balansae), ‘AU Sunrise’ and ‘Dixie’ crimson clover (T. incarnatum), ‘Cherokee’ red clover (T. pratense), common and ‘AU Early Cover’ hairy vetch (Vicia villosa), ‘Cahaba White’ vetch (V. sativa), and ‘Wrens Abruzzi’ rye. In the greenhouse tests, egg production was greatest on berseem clover, Dixie crimson clover, AU Early Cover hairy vetch, and common hairy vetch; intermediate on Balansa clover and AU Sunrise crimson clover; and least on rye, Cahaba White vetch, and Cherokee red clover. In both 2002 and 2003 field tests, enough heat units were accumulated between 1 January and 20 May for the nematode to complete two generations. Both AU Early Cover and common hairy vetch led to greater root galling than fallow in the subsequent cotton crop; they also supported high reproduction of M. incognita in the greenhouse. Rye and Cahaba White vetch did not increase root galling on cotton and were relatively poor hosts for M. incognita. Only those legumes that increased populations of M. incognita reduced cotton yield. In the southern US, M. incognita can complete one to two generations on a susceptible winter cover crop, so cover crops that support high nematode reproduction may lead to damage and yield losses in the following cotton crop. Planting rye or Meloidogyne-resistant legumes as winter cover crops will lower the risk of

  2. Reproduction of Meloidogyne incognita on Winter Cover Crops Used in Cotton Production.

    PubMed

    Timper, Patricia; Davis, Richard F; Tillman, P Glynn

    2006-03-01

    Substantial reproduction of Meloidogyne incognita on winter cover crops may lead to damaging populations in a subsequent cotton (Gossypium hirsutum) crop. The amount of population increase during the winter depends on soil temperature and the host status of the cover crop. Our objectives were to quantify M. incognita race 3 reproduction on rye (Secale cereale) and several leguminous cover crops and to determine if these cover crops increase population densities of M. incognita and subsequent damage to cotton. The cover crops tested were 'Bigbee' berseem clover (Trifolium alexandrinum), 'Paradana' balansa clover (T. balansae), 'AU Sunrise' and 'Dixie' crimson clover (T. incarnatum), 'Cherokee' red clover (T. pratense), common and 'AU Early Cover' hairy vetch (Vicia villosa), 'Cahaba White' vetch (V. sativa), and 'Wrens Abruzzi' rye. In the greenhouse tests, egg production was greatest on berseem clover, Dixie crimson clover, AU Early Cover hairy vetch, and common hairy vetch; intermediate on Balansa clover and AU Sunrise crimson clover; and least on rye, Cahaba White vetch, and Cherokee red clover. In both 2002 and 2003 field tests, enough heat units were accumulated between 1 January and 20 May for the nematode to complete two generations. Both AU Early Cover and common hairy vetch led to greater root galling than fallow in the subsequent cotton crop; they also supported high reproduction of M. incognita in the greenhouse. Rye and Cahaba White vetch did not increase root galling on cotton and were relatively poor hosts for M. incognita. Only those legumes that increased populations of M. incognita reduced cotton yield. In the southern US, M. incognita can complete one to two generations on a susceptible winter cover crop, so cover crops that support high nematode reproduction may lead to damage and yield losses in the following cotton crop. Planting rye or Meloidogyne-resistant legumes as winter cover crops will lower the risk of increased nematode populations

  3. Rainfall as a trigger for stratification and winter phytoplankton growth in temperate shelf seas

    NASA Astrophysics Data System (ADS)

    Jardine, Jenny; Palmer, Matthew; Mahaffey, Claire; Holt, Jason; Mellor, Adam; Wakelin, Sarah

    2017-04-01

    We present new data from ocean gliders to investigate physical controls on stratification and phytoplankton dynamics, collected in the Celtic Sea between November 2014 and August 2015 as part of the UK Shelf Sea Biogeochemistry programme. This presentation focuses on the winter period (Jan-March) when the diurnal heating cycle results in regular but weak near surface stratification followed by night-time convection. Despite low light conditions, this daily cycle often promotes a daytime increase in observed chlorophyll fluorescence, indicative of phytoplankton growth. This daily cycle is occasionally interrupted when buoyancy inputs are sufficient to outcompete night-time convection and result in short-term periods of sustained winter stratification, typically lasting 2-3 days. Sustained stratification often coincides with periods of heavy rainfall, suggesting freshwater input from precipitation may play a role on these events by producing a subtle yet significant freshening of the surface layer of the order of 0.005 PSU. Comparing rainfall estimates with observed salinity changes confirms rainfall to often be the initiator of these winter stratification periods. As winter winds subside and solar heating increases towards spring, the water column becomes more susceptible to periods of halo-stratification, such that heavy rainfall during the winter-spring transition is likely to promote sustained stratification. The timing and extent of a heavy rainfall event in March 2015 does suggest it may be the critical trigger for shelf-wide stratification that eventually instigates the spring bloom. We propose that the timing of these downpours relative to the daily heating cycle can be a triggering mechanism for both short term and seasonal stratification in shelf seas, and so play a critical role in winter and early spring phytoplankton growth and the shelf sea carbon cycle. We further test the importance of this process using historical data, and results from the NEMO-AMM7

  4. Sochi, Russia Winter Olympic Sites Mountain Cluster

    NASA Image and Video Library

    2014-02-05

    The 2014 Winter Olympic ski runs may be rated double black diamond, but theyre not quite as steep as they appear in this image acquired by NASA Terra spacecraft, of the skiing and snowboarding sites for the Sochi Winter Olympic Games.

  5. Link between the Barents Oscillation and recent boreal winter cooling over the Asian midlatitudes

    NASA Astrophysics Data System (ADS)

    Shu, Qi; Qiao, Fangli; Song, Zhenya; Song, Yajuan

    2018-01-01

    The link between boreal winter cooling over the midlatitudes of Asia and the Barents Oscillation (BO) since the late 1980s is discussed in this study, based on five datasets. Results indicate that there is a large-scale boreal winter cooling during 1990-2015 over the Asian midlatitudes, and that it is a part of the decadal oscillations of long-term surface air temperature (SAT) anomalies. The SAT anomalies over the Asian midlatitudes are significantly correlated with the BO in boreal winter. When the BO is in its positive phase, anomalously high sea level pressure over the Barents region, with a clockwise wind anomaly, causes cold air from the high latitudes to move over the midlatitudes of Asia, resulting in anomalous cold conditions in that region. Therefore, the recent increasing trend of the BO has contributed to recent winter cooling over the Asian midlatitudes.

  6. Sex-specific differences in winter distribution patterns of canvasbacks

    USGS Publications Warehouse

    Nichols, J.D.; Haramis, G.M.

    1980-01-01

    Winter band recovery distributions of North American Canvasbacks (Aythya valisineria) suggested that males and females exhibit comparable degrees of fidelity to general wintering areas. Of birds banded during the winter, the proportion of males was found to be higher in northern than in southern areas. Winter band recovery distributions of birds banded in particular areas during the summer were found to differ significantly between sexes, with females being recovered farther south. Factors that may have affected the evolution of sex-specific wintering distributions include: (1) possible reproductive benefits derived by males who winter in the north and thus reach northerly breeding areas early; (2) sexual dimorphism in body size, which may render the smaller females especially susceptible to periods of inclement weather and food shortages; and (3) interactions between sexes in which males may control food supply when food is scarce. Two lines of evidence from field data on Canvasbacks in the Chesapeake Bay suggest the existence of competition between males and females. First, Canvasbacks trapped during winter in smaller bodies of water tended to have higher proportions of females and weigh less than birds trapped in large open bodies of water. Second, analysis of aerial photographs of wintering rafts of Canvasbacks showed patterns of intersexual segregation, with females being found more frequently on peripheral areas of rafts.

  7. [Effects of different winter cover crops on soil organic carbon in a double cropping rice paddy field.

    PubMed

    Tang, Hai Ming; Cheng, Kai Kai; Xiao, Xiao Ping; Tang, Wen Guang; Wang, Ke; Li, Chao; Zhang, Fan; Sun, Yu Tao

    2017-02-01

    In a double cropping rice field experiment, effects of five winter cover crops on the total organic carbon (TOC), active organic carbon (AOC), carbon pool management index (CPMI) and organic carbon storage were studied in three soil layers (0-5, 5-10 and 10-20 cm).Winter cover crops of ryegrass (Ry), Chinese milk vetch (Mv), potato (Po), and rape (Ra) between two rice crops were compared with fallow as control (CK). The results showed that the TOC and AOC contents under Ry, Mv, Po and Ra treatments were higher than those of CK in all three la-yers. Meanwhile, the TOC and AOC contents in Po treatment were higher than those of other treatments. Compared with CK, the AOC, activity index (AI), carbon pool index (CPI) and CPMI in the soil were improved through the recycling of winter cover crops straw. The AOC, AI, CPI and CPMI in the studied layers increased in order of Po>Mv>Ry>Ra>CK. The results indicated that the recycling of winter cover crops straw promoted the storage of SOC in the 0-20 cm soil profile as compared with CK. The strongest effect of the winter cover crops on the SOC storage occurred in Mv treatment, followed by Mv and Po treatments, and the SOC storage increased with the increasing soil depth.

  8. The Influence of Snowmobile Trails on Coyote Movements during Winter in High-Elevation Landscapes

    PubMed Central

    Gese, Eric M.; Dowd, Jennifer L. B.; Aubry, Lise M.

    2013-01-01

    Competition between sympatric carnivores has long been of interest to ecologists. Increased understanding of these interactions can be useful for conservation planning. Increased snowmobile traffic on public lands and in habitats used by Canada lynx (Lynx canadensis) remains controversial due to the concern of coyote (Canis latrans) use of snowmobile trails and potential competition with lynx. Determining the variables influencing coyote use of snowmobile trails has been a priority for managers attempting to conserve lynx and their critical habitat. During 2 winters in northwest Wyoming, we backtracked coyotes for 265 km to determine how varying snow characteristics influenced coyote movements; 278 km of random backtracking was conducted simultaneously for comparison. Despite deep snow (>1 m deep), radio-collared coyotes persisted at high elevations (>2,500 m) year-round. All coyotes used snowmobile trails for some portion of their travel. Coyotes used snowmobile trails for 35% of their travel distance (random: 13%) for a mean distance of 149 m (random: 59 m). Coyote use of snowmobile trails increased as snow depth and penetrability off trails increased. Essentially, snow characteristics were most influential on how much time coyotes spent on snowmobile trails. In the early months of winter, snow depth was low, yet the snow column remained dry and the coyotes traveled off trails. As winter progressed and snow depth increased and snow penetrability increased, coyotes spent more travel distance on snowmobile trails. As spring approached, the snow depth remained high but penetrability decreased, hence coyotes traveled less on snowmobile trails because the snow column off trail was more supportive. Additionally, coyotes traveled closer to snowmobile trails than randomly expected and selected shallower snow when traveling off trails. Coyotes also preferred using snowmobile trails to access ungulate kills. Snow compaction from winter recreation influenced coyote

  9. The influence of snowmobile trails on coyote movements during winter in high-elevation landscapes.

    PubMed

    Gese, Eric M; Dowd, Jennifer L B; Aubry, Lise M

    2013-01-01

    Competition between sympatric carnivores has long been of interest to ecologists. Increased understanding of these interactions can be useful for conservation planning. Increased snowmobile traffic on public lands and in habitats used by Canada lynx (Lynx canadensis) remains controversial due to the concern of coyote (Canis latrans) use of snowmobile trails and potential competition with lynx. Determining the variables influencing coyote use of snowmobile trails has been a priority for managers attempting to conserve lynx and their critical habitat. During 2 winters in northwest Wyoming, we backtracked coyotes for 265 km to determine how varying snow characteristics influenced coyote movements; 278 km of random backtracking was conducted simultaneously for comparison. Despite deep snow (>1 m deep), radio-collared coyotes persisted at high elevations (>2,500 m) year-round. All coyotes used snowmobile trails for some portion of their travel. Coyotes used snowmobile trails for 35% of their travel distance (random: 13%) for a mean distance of 149 m (random: 59 m). Coyote use of snowmobile trails increased as snow depth and penetrability off trails increased. Essentially, snow characteristics were most influential on how much time coyotes spent on snowmobile trails. In the early months of winter, snow depth was low, yet the snow column remained dry and the coyotes traveled off trails. As winter progressed and snow depth increased and snow penetrability increased, coyotes spent more travel distance on snowmobile trails. As spring approached, the snow depth remained high but penetrability decreased, hence coyotes traveled less on snowmobile trails because the snow column off trail was more supportive. Additionally, coyotes traveled closer to snowmobile trails than randomly expected and selected shallower snow when traveling off trails. Coyotes also preferred using snowmobile trails to access ungulate kills. Snow compaction from winter recreation influenced coyote

  10. Spatial and temporal variation in daily temperature indices in summer and winter seasons over India (1969-2012)

    NASA Astrophysics Data System (ADS)

    Kumar, Naresh; Jaswal, A. K.; Mohapatra, M.; Kore, P. A.

    2017-08-01

    Spatial and temporal variations in summer and winter extreme temperature indices are studied by using daily maximum and minimum temperatures data from 227 surface meteorological stations well distributed over India for the period 1969-2012. For this purpose, time series for six extreme temperature indices namely, hot days (HD), very hot days (VHD), extremely hot days (EHD), cold nights (CN), very cold nights (VCN), and extremely cold nights (ECN) are calculated for all the stations. In addition, time series for mean extreme temperature indices of summer and winter seasons are also analyzed. Study reveals high variability in spatial distribution of threshold temperatures of extreme temperature indices over the country. In general, increasing trends are observed in summer hot days indices and decreasing trends in winter cold night indices over most parts of the country. The results obtained in this study indicate warming in summer maximum and winter minimum temperatures over India. Averaged over India, trends in summer hot days indices HD, VHD, and EHD are significantly increasing (+1.0, +0.64, and +0.32 days/decade, respectively) and winter cold night indices CN, VCN, and ECN are significantly decreasing (-0.93, -0.47, and -0.15 days/decade, respectively). Also, it is observed that the impact of extreme temperature is higher along the west coast for summer and east coast for winter.

  11. Does the recent warming hiatus exist over northern Asia for winter wind chill temperature?

    NASA Astrophysics Data System (ADS)

    Ma, Ying

    2017-04-01

    Wind chill temperature (WCT) describes the joint effect of wind velocity and air temperature on exposed body skin and could support policy makers in designing plans to reduce the risks of notably cold and windy weather. This study examined winter WCT over northern Asia during 1973-2013 by analyzing in situ station data. The winter WCT warming rate over the Tibetan Plateau slowed during 1999-2013 (-0.04 °C/decade) compared with that during 1973-1998 (0.67 °C/decade). The winter WCT warming hiatus has also been observed in the remainder of Northern Asia with trends of 1.11 °C/decade during 1973-1998 but -1.02 °C/decade during 1999-2013, except for the Far East of Russia (FE), where the winter WCT has continued to heat up during both the earlier period of 1973-1998 (0.54 °C/decade) and the recent period of 1999-2013 (0.75 °C/decade). The results indicate that the influence of temperature on winter WCT is greater than that of wind speed over northern Asia. Atmospheric circulation changes associated with air temperature and wind speed were analyzed to identify the causes for the warming hiatus of winter WCT over northern Asia. The distributions of sea level pressure and 500 hPa height anomalies during 1999-2013 transported cold air from the high latitudes to middle latitudes, resulting in low air temperature over Northern Asia except for the Far East of Russia. Over the Tibetan Plateau, the increase in wind speed offset the increase in air temperature during 1999-2013. For the Far East, the southerly wind from the Western Pacific drove the temperature up during the 1999-2013 period via warm advection.

  12. A Phenology-based Method For Identifying the Planting Fraction of Winter Wheat Using Moderate-resolution Satellite Data

    NASA Astrophysics Data System (ADS)

    Dong, J.; Liu, W.; Han, W.; Lei, T.; Xia, J.; Yuan, W.

    2017-12-01

    Winter wheat is a staple food crop for most of the world's population, and the area and spatial distribution of winter wheat are key elements in estimating crop production and ensuring food security. However, winter wheat planting areas contain substantial spatial heterogeneity with mixed pixels for coarse- and moderate-resolution satellite data, leading to significant errors in crop acreage estimation. This study has developed a phenology-based approach using moderate-resolution satellite data to estimate sub-pixel planting fractions of winter wheat. Based on unmanned aerial vehicle (UAV) observations, the unique characteristics of winter wheat with high vegetation index values at the heading stage (May) and low values at the harvest stage (June) were investigated. The differences in vegetation index between heading and harvest stages increased with the planting fraction of winter wheat, and therefore the planting fractions were estimated by comparing the NDVI differences of a given pixel with those of predetermined pure winter wheat and non-winter wheat pixels. This approach was evaluated using aerial images and agricultural statistical data in an intensive agricultural region, Shandong Province in North China. The method explained 60% and 85% of the spatial variation in county- and municipal-level statistical data, respectively. More importantly, the predetermined pure winter wheat and non-winter wheat pixels can be automatically identified using MODIS data according to their NDVI differences, which strengthens the potential to use this method at regional and global scales without any field observations as references.

  13. Calcium intake in winter pregnancy attenuates impact of vitamin D inadequacy on urine NTX, a marker of bone resorption.

    PubMed

    O'Brien, Eileen C; Kilbane, Mark T; McKenna, Malachi J; Segurado, Ricardo; Geraghty, Aisling A; McAuliffe, Fionnuala M

    2018-04-01

    Pregnancy is characterised by increased bone turnover, but high bone turnover with resorption exceeding formation may lead to negative maternal bone remodelling. Recent studies are conflicting regarding the effect of calcium on skeletal health in pregnancy. The aim of this study was to examine the seasonal effect of serum 25-hydroxyvitamin D (25OHD) and dietary calcium on a marker of bone resorption. This was prospective study of 205 pregnant women [two cohorts; early pregnancy at 13 weeks (n = 96), and late pregnancy at 28 weeks (n = 109)]. Serum 25OHD and urine cross-linked N-telopeptides of type I collagen (uNTX) were measured at both time points. Intakes of vitamin D and calcium were recorded using 3-day food diaries at each trimester. Compared to summer pregnancies, winter pregnancies had significantly lower 25OHD and significantly higher uNTX. Higher calcium intakes were negatively correlated with uNTX in winter, but not summer. In late pregnancy, compared to those reporting calcium intakes ≥1000 mg/day, intakes of <1000 mg/day were associated with a greater increase in uNTX in winter pregnancies than in summer (41.8 vs. 0.9%). Increasing calcium intake in winter by 200 mg/day predicted a 13.3% reduction in late pregnancy uNTX. In late pregnancy, during winter months when 25OHD is inadequate, intakes of dietary calcium <1000 mg/day were associated with significantly increased bone resorption (uNTX). Additional dietary calcium is associated with reduced bone resorption in late pregnancy, with greater effect observed in winter. Further research regarding optimal dietary calcium and 25OHD in pregnancy is required, particularly for women gestating through winter.

  14. The seasonal cycle of the Lazarev Sea macrozooplankton community and a potential shift to top-down trophic control in winter

    NASA Astrophysics Data System (ADS)

    Hunt, B. P. V.; Pakhomov, E. A.; Siegel, V.; Strass, V.; Cisewski, B.; Bathmann, U.

    2011-07-01

    Between 2004 and 2008, during the German Southern Ocean GLOBEC programme, four large scale bio-oceanographic surveys were conducted in the Lazarev Sea for the Lazarev Sea Krill Survey (LAKRIS). These surveys were completed in Autumn (April-May) 2004, Summer (December-January) 2005/06, Winter (July-August) 2006, and Summer (December-January) 2007/08. On each occasion macrozooplankton communities were sampled by RMT-8 in the upper 200 m of the water column. Chlorophyll a biomass averaged ˜1.5 mg m -3 (max=8.2 mg m -3) in Summer 05/06, 0.88 mg m -3 (max=2.77 mg m -3) in Summer 07/08, 0.24 mg m -3 (max=0.73 mg m -3) in Autumn 04, and 0.042 mg m -3 (max=0.1 mg m -3) in Winter 06. Macrozooplankton densities did not differ significantly between seasons and were 53, 68, 59, and 48 ind. 1000 m -3 in Summer 05/06, Summer 07/08, Autumn, and Winter, respectively. Total macrozooplankton biomass, however, increased significantly from summer (0.88 and 0.97 g dry weight 1000 m -3 in Summer 05/06 and Summer 07/08, respectively) to Autumn 04 (2.66 g dry weight 1000 m -3) and Winter 06 levels (1.75 g dry weight 1000 m -3). This biomass increase was due to both an increased occurrence of Euphausia superba and fish and a shift to a larger size structure in the latter group. Siphonophores (predominantly Diphyes antarctica), chaetognaths (predominantly Eukrohnia hamata and Sagitta gazellae) and euphausiids (predominantly Thysanoessa macrura and E. superba) contributed >80% to total densities in all four surveys. However, a strong and distinctive change in assemblage structure was observed between seasons. Key amongst these was a shift within the euphausiids from a dominance of T. macrura in summer to that of E. superba in autumn and winter; a winter decrease in E. hamata; an autumn and winter decrease in Tomopteris sp.; and a winter increase in the abundance of the grazers Clio pyramidata sulcata and Ihlea racovitzai, hyperiids, and the myctophid fish Electrona antarctica. Carnivorous

  15. Winter survival of microbial contaminants in soil: an in situ verification.

    PubMed

    Bucci, Antonio; Allocca, Vincenzo; Naclerio, Gino; Capobianco, Giovanni; Divino, Fabio; Fiorillo, Francesco; Celico, Fulvio

    2015-01-01

    The aim of the research was to evaluate, at site scale, the influence of freezing and freeze/thaw cycles on the survival of faecal coliforms and faecal enterococci in soil, in a climate change perspective. Before the winter period and during grazing, viable cells of faecal coliforms and faecal enterococci were detected only in the first 10 cm below ground, while, after the winter period and before the new seasonal grazing, a lower number of viable cells of both faecal indicators was detected only in some of the investigated soil profiles, and within the first 5 cm. Taking into consideration the results of specific investigations, we hypothesise that the non-uniform spatial distribution of grass roots within the studied soil can play an important role in influencing this phenomenon, while several abiotic factors do not play any significant role. Taking into account the local trend in the increase of air temperature, a different distribution of microbial pollution over time is expected in spring waters, in future climate scenarios. The progressive increase in air temperature will cause a progressive decrease in freeze/thaw cycles at higher altitudes, minimising cold shocks on microbial cells, and causing spring water pollution also during winter. Copyright © 2014. Published by Elsevier B.V.

  16. Slow acidification of the winter mixed layer in the subarctic western North Pacific

    NASA Astrophysics Data System (ADS)

    Wakita, Masahide; Nagano, Akira; Fujiki, Tetsuichi; Watanabe, Shuichi

    2017-08-01

    We used carbon dioxide (CO2) system data collected during 1999-2015 to investigate ocean acidification at time series sites in the western subarctic region of the North Pacific Ocean. The annual mean pH at station K2 decreased at a rate of 0.0025 ± 0.0010 year-1 mostly in response to oceanic uptake of anthropogenic CO2. The Revelle factor increased rapidly (0.046 ± 0.022 year-1), an indication that the buffering capacity of this region of the ocean has declined faster than at other time series sites. In the western subarctic region, the pH during the winter decline at a slower rate of 0.0008 ± 0.0004 year-1. This was attributed to a reduced rate of increase of dissolved inorganic carbon (DIC) and an increase of total alkalinity (TA). The reduction of DIC increase was caused by the decline of surface water density associated with the pycnocline depression and the reduction of vertical diffusion flux from the upper pycnocline. These physical changes were probably caused by northward shrinkage of the western subarctic gyre and global warming. Meanwhile, the contribution of the density decline to the TA increase is canceled out by that of the reduced vertical diffusive flux. We speculated that the winter TA increase is caused mainly by the accumulation of TA due to the weakened calcification by organisms during the winter.

  17. Changes in the status of harvested rice fields in the Sacramento Valley, California: Implications for wintering waterfowl.

    USGS Publications Warehouse

    Miller, Michael R.; Garr, Jay D.; Coates, Peter S.

    2010-01-01

    Harvested rice fields provide critical foraging habitat for wintering waterfowl in North America, but their value depends upon post-harvest treatments. We visited harvested ricefields in the Sacramento Valley, California, during the winters of 2007 and 2008 (recent period) and recorded their observed status as harvested (standing or mechanically modified stubble), burned, plowed, or flooded. We compared these data with those from identical studies conducted during the 1980s (early period). We documented substantial changes in field status between periods. First, the area of flooded rice increased 4-5-fold, from about 15% to >40% of fields, because of a 3-4-fold increase in the percentage of fields flooded coupled with a 37-41% increase in the area of rice produced. Concurrently, the area of plowed fields increased from 35% of fields, burned fields declined from about 40% to 1%, and fields categorized as harvested declined from 22-54% to <15%. The increased flooding has likely increased access to food resources for wintering waterfowl, but this benefit may not be available to some goose species, and may be at least partially countered by the increase of plowed fields, especially those left dry, and the decrease of fields left as harvested.We encourage waterfowl managers to implement a rice field status survey in the Sacramento Valley and other North American rice growing regions as appropriate to support long-term monitoring programs and wetland habitat conservation planning for wintering waterfowl.

  18. Winter in Antarctica: dark, cold, windy, and .... wet?? Measurements and modeling of extensive wintertime surface melt

    NASA Astrophysics Data System (ADS)

    Kuipers Munneke, P.; Luckman, A. J.; Bevan, S. L.; Gilbert, E.; Smeets, P.; van den Broeke, M. R.; Wang, W.; Zender, C. S.; Ashmore, D. W.; Hubbard, B. P.; Orr, A.; King, J.

    2017-12-01

    We know that increased surface melt, driven by atmospheric warming, contributed to the collapse of ice shelves as observed in the Antarctic Peninsula. This has induced grounded-ice acceleration and increased ice discharge. You may associate this surface melt with the austral summer season, with plenty of solar radiation driving the melt. In contrast, winter in Antarctica evokes images of darkness, snow, and cold. However, we will make you rethink this picture by presenting observations of frequent snow surface melt in winter, from a weather station located in a previously unsurveyed area of the Larsen C Ice Shelf. Peak intensities of this wintertime melt even exceed summertime values, and thermal satellite images show that large ponds of meltwater are formed at the surface in the pitch-dark Antarctic winter. Obviously, we wanted to find out what could drive these strong melt events if it's not the sun. It turns out that these multi-day melt events occur when warm and dry föhn winds descend from the Antarctic Peninsula mountains. Simulations with a high-resolution weather model confirm that these winds generate turbulent fluxes of sensible heat, leading to melt fluxes in excess of 200 W m-2. In 2015 and 2016, about 23% of the annual melt was produced in winter. We use satellite radar to show that winter melt occurs on many more places in the Antarctic Peninsula. It happens every year, although in some years the melting is much more widespread than in others. We think that wintertime melt matters as its refreezing warms the snow and increases snow density. In this way, winter melt preconditions the ice shelf for more extensive surface drainage, potentially leading to meltwater-driven instability.

  19. Evaluation and economic value of winter weather forecasts

    NASA Astrophysics Data System (ADS)

    Snyder, Derrick W.

    State and local highway agencies spend millions of dollars each year to deploy winter operation teams to plow snow and de-ice roadways. Accurate and timely weather forecast information is critical for effective decision making. Students from Purdue University partnered with the Indiana Department of Transportation to create an experimental winter weather forecast service for the 2012-2013 winter season in Indiana to assist in achieving these goals. One forecast product, an hourly timeline of winter weather hazards produced daily, was evaluated for quality and economic value. Verification of the forecasts was performed with data from the Rapid Refresh numerical weather model. Two objective verification criteria were developed to evaluate the performance of the timeline forecasts. Using both criteria, the timeline forecasts had issues with reliability and discrimination, systematically over-forecasting the amount of winter weather that was observed while also missing significant winter weather events. Despite these quality issues, the forecasts still showed significant, but varied, economic value compared to climatology. Economic value of the forecasts was estimated to be 29.5 million or 4.1 million, depending on the verification criteria used. Limitations of this valuation system are discussed and a framework is developed for more thorough studies in the future.

  20. Estimating flow rates to optimize winter habitat for centrarchid fish in Mississippi River (USA) backwaters

    USGS Publications Warehouse

    Johnson, Barry L.; Knights, Brent C.; Barko, John W.; Gaugush, Robert F.; Soballe, David M.; James, William F.

    1998-01-01

    The backwaters of large rivers provide winter refuge for many riverine fish, but they often exhibit low dissolved oxygen levels due to high biological oxygen demand and low flows. Introducing water from the main channel can increase oxygen levels in backwaters, but can also increase current velocity and reduce temperature during winter, which may reduce habitat suitability for fish. In 1993, culverts were installed to introduce flow to the Finger Lakes, a system of six backwater lakes on the Mississippi River, about 160 km downstream from Minneapolis, Minnesota. The goal was to improve habitat for bluegills and black crappies during winter by providing dissolved oxygen concentrations >3 mg/L, current velocities <1 cm/s, and temperatures >1°C. To achieve these conditions, we used data on lake volume and oxygen demand to estimate the minimum flow required to maintain 3 mg/L of dissolved oxygen in each lake. Estimated flows ranged from 0.02 to 0.14 m3/s among lakes. Data gathered in winter 1994 after the culverts were opened, indicated that the estimated flows met habitat goals, but that thermal stratification and lake morphometry can reduce the volume of optimal habitat created.

  1. Influence of Honey Bee Genotype and Wintering Method on Wintering Performance of Varroa destructor (Parasitiformes: Varroidae)-Infected Honey Bee (Hymenoptera: Apidae) Colonies in a Northern Climate.

    PubMed

    Bahreini, Rassol; Currie, Robert W

    2015-08-01

    The objective of this study was to assess the effectiveness of a cooperative breeding program designed to enhance winter survival of honey bees (Apis mellifera L.) when exposed to high levels of varroa (Varroa destructor Anderson and Trueman) in outdoor-wintered and indoor-wintered colonies. Half of the colonies from selected and unselected stocks were randomly assigned to be treated with late autumn oxalic acid treatment or to be left untreated. Colonies were then randomly assigned to be wintered either indoors (n = 37) or outdoors (n = 40). Late autumn treatment with oxalic acid did not improve wintering performance. However, genotype of bees affected colony survival and the proportion of commercially viable colonies in spring, as indicated by greater rates of colony survival and commercially viable colonies for selected stock (43% survived and 33% were viable) in comparison to unselected stock (19% survived and 9% were viable) across all treatment groups. Indoor wintering improved spring bee population score, proportion of colonies surviving, and proportion of commercially viable colonies relative to outdoor wintering (73% of selected stock and 41% of unselected stock survived during indoor wintering). Selected stock showed better "tolerance" to varroa as the selected stock also maintained higher bee populations relative to unselected stock. However, there was no evidence of "resistance" in selected colonies (reduced mite densities). Collectively, this experiment showed that breeding can improve tolerance to varroa and this can help minimize colony loss through winter and improve colony wintering performance. Overall, colony wintering success of both genotypes of bees was better when colonies were wintered indoors than when colonies were wintered outdoors. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Drought and Winter Drying (Pest Alert)

    Treesearch

    USDA Forest Service

    Drought and winter drying have periodically caused major damage to trees. Drought reduces the amount of water available in the soil. In the case of winter drying, the water may be in the soil, but freezing of the soil makes the water unavailable to the tree. In both cases, more water is lost through transpiration than is available to the plant. Symptoms of drought and...

  3. 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.

  4. Exploring new alleles for frost tolerance in winter rye.

    PubMed

    Erath, Wiltrud; Bauer, Eva; Fowler, D Brian; Gordillo, Andres; Korzun, Viktor; Ponomareva, Mira; Schmidt, Malthe; Schmiedchen, Brigitta; Wilde, Peer; Schön, Chris-Carolin

    2017-10-01

    Rye genetic resources provide a valuable source of new alleles for the improvement of frost tolerance in rye breeding programs. Frost tolerance is a must-have trait for winter cereal production in northern and continental cropping areas. Genetic resources should harbor promising alleles for the improvement of frost tolerance of winter rye elite lines. For frost tolerance breeding, the identification of quantitative trait loci (QTL) and the choice of optimum genome-based selection methods are essential. We identified genomic regions involved in frost tolerance of winter rye by QTL mapping in a biparental population derived from a highly frost tolerant selection from the Canadian cultivar Puma and the European elite line Lo157. Lines per se and their testcrosses were phenotyped in a controlled freeze test and in multi-location field trials in Russia and Canada. Three QTL on chromosomes 4R, 5R, and 7R were consistently detected across environments. The QTL on 5R is congruent with the genomic region harboring the Frost resistance locus 2 (Fr-2) in Triticeae. The Puma allele at the Fr-R2 locus was found to significantly increase frost tolerance. A comparison of predictive ability obtained from the QTL-based model with different whole-genome prediction models revealed that besides a few large, also small QTL effects contribute to the genomic variance of frost tolerance in rye. Genomic prediction models assigning a high weight to the Fr-R2 locus allow increasing the selection intensity for frost tolerance by genome-based pre-selection of promising candidates.

  5. Winter photosynthesis of red spruce from three Vermont seed sources

    Treesearch

    P.G. Schaberg; R.C. Wilkinson; J.B. Shane; J.R. Donnelly; P.F. Cali

    1995-01-01

    We evaluated winter (January through March) carbon assimilation of red spruce (Picea rubens Sarg.) from three Vermont seed sources grown in a common garden in northwestern Vermont. Although CO2 exchange rates were generally low, net photosynthetic rates increased during two prolonged thaws. Significant correlations between CO...

  6. Subseasonal Reversal of East Asian Surface Temperature Variability in Winter 2014/15

    NASA Astrophysics Data System (ADS)

    Xu, Xinping; Li, Fei; He, Shengping; Wang, Huijun

    2018-06-01

    Although there has been a considerable amount of research conducted on the East Asian winter-mean climate, subseasonal surface air temperature (SAT) variability reversals in the early and late winter remain poorly understood. In this study, we focused on the recent winter of 2014/15, in which warmer anomalies dominated in January and February but colder conditions prevailed in December. Moreover, Arctic sea-ice cover (ASIC) in September-October 2014 was lower than normal, and warmer sea surface temperature (SST) anomalies occurred in the Niño4 region in winter, together with a positive Pacific Decadal Oscillation (PDO|+) phase. Using observational data and CMIP5 historical simulations, we investigated the PDO|+ phase modulation upon the winter warm Niño4 phase (autumn ASIC reduction) influence on the subseasonal SAT variability of East Asian winter. The results show that, under a PDO|+ phase modulation, warm Niño4 SST anomalies are associated with a subseasonal delay of tropical surface heating and subsequent Hadley cell and Ferrel cell intensification in January-February, linking the tropical and midlatitude regions. Consistently, the East Asian jet stream (EAJS) is significantly decelerated in January-February and hence promotes the warm anomalies over East Asia. Under the PDO|+ phase, the decrease in ASIC is related to cold SST anomalies in the western North Pacific, which increase the meridional temperature gradient and generate an accelerated and westward-shifted EAJS in December. The westward extension of the EAJS is responsible for the eastward-propagating Rossby waves triggered by declining ASIC and thereby favors the connection between ASIC and cold conditions over East Asia.

  7. Is the OJIP Test a Reliable Indicator of Winter Hardiness and Freezing Tolerance of Common Wheat and Triticale under Variable Winter Environments?

    PubMed Central

    Rapacz, Marcin; Sasal, Monika; Kalaji, Hazem M.; Kościelniak, Janusz

    2015-01-01

    OJIP analysis, which explores changes in photosystem II (PSII) photochemical performance, has been used as a measure of plant susceptibility to stress. However, in the case of freezing tolerance and winter hardiness, which are highly environmentally variable, the use of this method can give ambiguous results depending on the species as well as the sampling year and time. To clarify this issue, we performed chlorophyll fluorescence measurements over three subsequent winters (2010/11, 2011/12 and 2012/13) on 220 accessions of common winter wheat and 139 accessions of winter triticale. After freezing, leaves were collected from cold-acclimated plants in the laboratory and field-grown plants. Observations of field survival in seven locations across Poland and measurements of freezing tolerance of the studied plants were also recorded. Our results confirm that the OJIP test is a reliable indicator of winter hardiness and freezing tolerance of common wheat and triticale under unstable winter environments. Regardless of species, the testing conditions giving the most reliable results were identical, and the reliability of the test could be easily checked by analysis of some relationships between OJIP-test parameters. We also found that triticale is more winter hardy and freezing tolerant than wheat. In addition, the two species were characterized by different patterns of photosynthetic apparatus acclimation to cold. PMID:26230839

  8. Combined use of Landsat-8 and Sentinel-2A images for winter crop mapping and winter wheat yield assessment at regional scale.

    PubMed

    Skakun, Sergii; Vermote, Eric; Roger, Jean-Claude; Franch, Belen

    2017-01-01

    Timely and accurate information on crop yield is critical to many applications within agriculture monitoring. Thanks to its coverage and temporal resolution, coarse spatial resolution satellite imagery has always been a source of valuable information for yield forecasting and assessment at national and regional scales. With availability of free images acquired by Landsat-8 and Sentinel-2 remote sensing satellites, it becomes possible to enable temporal resolution of an image every 3-5 days, and therefore, to develop next generation agriculture products at higher spatial resolution (30 m). This paper explores the combined use of Landsat-8 and Sentinel-2A for winter crop mapping and winter wheat assessment at regional scale. For the former, we adapt a previously developed approach for Moderate Resolution Imaging Spectroradiometer (MODIS) at 250 m resolution that allows automatic mapping of winter crops taking into account knowledge on crop calendar and without ground truth data. For the latter, we use a generalized winter wheat yield model that is based on NDVI-peak estimation and MODIS data, and further downscaled to be applicable at 30 m resolution. We show that integration of Landsat-8 and Sentinel-2A has a positive impact both for winter crop mapping and winter wheat yield assessment. In particular, the error of winter wheat yield estimates can be reduced up to 1.8 times comparing to the single satellite usage.

  9. Is the OJIP Test a Reliable Indicator of Winter Hardiness and Freezing Tolerance of Common Wheat and Triticale under Variable Winter Environments?

    PubMed

    Rapacz, Marcin; Sasal, Monika; Kalaji, Hazem M; Kościelniak, Janusz

    2015-01-01

    OJIP analysis, which explores changes in photosystem II (PSII) photochemical performance, has been used as a measure of plant susceptibility to stress. However, in the case of freezing tolerance and winter hardiness, which are highly environmentally variable, the use of this method can give ambiguous results depending on the species as well as the sampling year and time. To clarify this issue, we performed chlorophyll fluorescence measurements over three subsequent winters (2010/11, 2011/12 and 2012/13) on 220 accessions of common winter wheat and 139 accessions of winter triticale. After freezing, leaves were collected from cold-acclimated plants in the laboratory and field-grown plants. Observations of field survival in seven locations across Poland and measurements of freezing tolerance of the studied plants were also recorded. Our results confirm that the OJIP test is a reliable indicator of winter hardiness and freezing tolerance of common wheat and triticale under unstable winter environments. Regardless of species, the testing conditions giving the most reliable results were identical, and the reliability of the test could be easily checked by analysis of some relationships between OJIP-test parameters. We also found that triticale is more winter hardy and freezing tolerant than wheat. In addition, the two species were characterized by different patterns of photosynthetic apparatus acclimation to cold.

  10. Pre-wintering conditions and post-winter performance in a solitary bee

    USDA-ARS?s Scientific Manuscript database

    Notwithstanding lowered metabolism, and because diapausing insects have no access to food, diapause has an energetic cost that may affect post-diapause performance. Previous studies on the solitary bee Osmia lignaria have shown that prolonged pre-wintering periods (the time during which individuals ...

  11. Downstream movement of fall Chinook salmon juveniles in the lower Snake River reservoirs during winter and early spring

    USGS Publications Warehouse

    Tiffan, Kenneth F.; Kock, Tobias J.; Connor, William P.; Mullins, Frank; Steinhorst, R. Kirk

    2012-01-01

    We conducted a 3-year radiotelemetry study in the lower Snake River to (1) determine whether juvenile fall Chinook salmon Oncorhynchus tshawytscha pass dams during winter, when bypass systems and structures designed to prevent mortality are not operated; (2) determine whether downstream movement rate varies annually, seasonally, and from reservoir to reservoir; and (3) identify some of the factors that contribute to annual, seasonal, and spatial variation in downstream movement rate. Fall Chinook salmon juveniles moved downstream up to 169 km and at a sufficiently fast rate (7.5 km/d) such that large percentages (up to 93%) of the fish passed one or more dams during the winter. Mean downstream movement rate varied annually (9.2–11.3 km/d), increased from winter (7.5 km/d) to spring (16.4 km/d), and increased (from 6.9 to 16.8 km/d) as fish moved downstream from reservoir to reservoir. Fish condition factor at tagging explained some of the annual variation in downstream movement rate, whereas water particle velocity and temperature explained portions of the seasonal variation. An increase in migrational disposition as fish moved downstream helped to explain the spatial variation. The potential cost of winter movement might be reduced survival due to turbine passage at a time when the bypass systems and spillway passage structures are not operated. Efforts to understand and increase passage survival of winter migrants in large impoundments might help to rehabilitate some imperiled anadromous salmonid populations.

  12. Mixing and ageing in the polar lower stratosphere in winter 2015-2016

    NASA Astrophysics Data System (ADS)

    Krause, Jens; Hoor, Peter; Engel, Andreas; Plöger, Felix; Grooß, Jens-Uwe; Bönisch, Harald; Keber, Timo; Sinnhuber, Björn-Martin; Woiwode, Wolfgang; Oelhaf, Hermann

    2018-05-01

    We present data from winter 2015-2016, which were measured during the POLSTRACC (The Polar Stratosphere in a Changing Climate) aircraft campaign between December 2015 and March 2016 in the Arctic upper troposphere and lower stratosphere (UTLS). The focus of this work is on the role of transport and mixing between aged and potentially chemically processed air masses from the stratosphere which have midlatitude and low-latitude air mass fractions with small transit times originating at the tropical lower stratosphere. By combining measurements of CO, N2O and SF6 we estimate the evolution of the relative contributions of transport and mixing to the UTLS composition over the course of the winter. We find an increasing influence of aged stratospheric air partly from the vortex as indicated by decreasing N2O and SF6 values over the course of the winter in the extratropical lower and lowermost stratosphere between Θ = 360 K and Θ = 410 K over the North Atlantic and the European Arctic. Surprisingly we also found a mean increase in CO of (3.00 ± 1.64) ppbV from January to March relative to N2O in the lower stratosphere. We show that this increase in CO is consistent with an increased mixing of tropospheric air as part of the fast transport mechanism in the lower stratosphere surf zone. The analysed air masses were partly affected by air masses which originated at the tropical tropopause and were quasi-horizontally mixed into higher latitudes. This increase in the tropospheric air fraction partly compensates for ageing of the UTLS due to the diabatic descent of air masses from the vortex by horizontally mixed, tropospheric-influenced air masses. This is consistent with simulated age spectra from the Chemical Lagrangian Model of the Stratosphere (CLaMS), which show a respective fractional increase in tropospheric air with transit times under 6 months and a simultaneous increase in aged air from upper stratospheric and vortex regions with transit times longer than 2 years

  13. Heavy snow loads in Finnish forests respond regionally asymmetrically to projected climate change

    DOE PAGES

    Lehtonen, Ilari; Kamarainen, Matti; Gregow, Hilppa; ...

    2016-10-17

    This study examined the impacts of projected climate change on heavy snow loads on Finnish forests, where snow-induced forest damage occurs frequently. For snow-load calculations, we used daily data from five global climate models under representative concentration pathway (RCP) scenarios RCP4.5 and RCP8.5, statistically downscaled onto a high-resolution grid using a quantile-mapping method. Our results suggest that projected climate warming results in regionally asymmetric response on heavy snow loads in Finnish forests. In eastern and northern Finland, the annual maximum snow loads on tree crowns were projected to increase during the present century, as opposed to southern and western parts ofmore » the country. The change was rather similar both for heavy rime loads and wet snow loads, as well as for frozen snow loads. Only the heaviest dry snow loads were projected to decrease over almost the whole of Finland. Our results are aligned with previous snowfall projections, typically indicating increasing heavy snowfalls over the areas with mean temperature below -8 °C. In spite of some uncertainties related to our results, we conclude that the risk for snow-induced forest damage is likely to increase in the future in the eastern and northern parts of Finland, i.e. in the areas experiencing the coldest winters in the country. In conclusion, the increase is partly due to the increase in wet snow hazards but also due to more favourable conditions for rime accumulation in a future climate that is more humid but still cold enough.« less

  14. Heavy snow loads in Finnish forests respond regionally asymmetrically to projected climate change

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

    Lehtonen, Ilari; Kamarainen, Matti; Gregow, Hilppa

    This study examined the impacts of projected climate change on heavy snow loads on Finnish forests, where snow-induced forest damage occurs frequently. For snow-load calculations, we used daily data from five global climate models under representative concentration pathway (RCP) scenarios RCP4.5 and RCP8.5, statistically downscaled onto a high-resolution grid using a quantile-mapping method. Our results suggest that projected climate warming results in regionally asymmetric response on heavy snow loads in Finnish forests. In eastern and northern Finland, the annual maximum snow loads on tree crowns were projected to increase during the present century, as opposed to southern and western parts ofmore » the country. The change was rather similar both for heavy rime loads and wet snow loads, as well as for frozen snow loads. Only the heaviest dry snow loads were projected to decrease over almost the whole of Finland. Our results are aligned with previous snowfall projections, typically indicating increasing heavy snowfalls over the areas with mean temperature below -8 °C. In spite of some uncertainties related to our results, we conclude that the risk for snow-induced forest damage is likely to increase in the future in the eastern and northern parts of Finland, i.e. in the areas experiencing the coldest winters in the country. In conclusion, the increase is partly due to the increase in wet snow hazards but also due to more favourable conditions for rime accumulation in a future climate that is more humid but still cold enough.« less

  15. Comparison of camel tear proteins between summer and winter

    PubMed Central

    Chen, Ziyan; Shamsi, Farrukh A.; Li, Kaijun; Huang, Qiang; Al-Rajhi, Ali A.; Chaudhry, Imtiaz A.

    2011-01-01

    Purpose Proteins in the tear fluid have positive effects on maintaining the integrity and stabilization of the tear film, which is affected by several environmental factors. The aim of this study is to investigate seasonal variation of protein patterns in camel tears collected during the summer and winter season. Methods Tears from both eyes of 50 clinically normal camels (Camelus dromedarius) were collected in the summer (June – July) and in the winter (December – January) respectively. Pooled tear protein samples from two seasons were separated by SDS–PAGE and two-dimensional electrophoresis (2-DE). Protein spots of differential expression in two season gels were excised and subjected to in-gel digestion and identification by matrix assisted laser desorption/ionization-time of flight/time of flight-mass spectrum (MALDI-TOF/TOF-MS) analysis. Two differentially expressed proteins, lactoferrin (LF) and vitelline membrane outer layer protein 1 homolog (VMO1 homolog), were validated by western blotting. Results Thirteen well resolved bands were detected in SDS–PAGE gels of both summer and winter camel tears. By band densitometry, significantly higher intensities of band 6, 7, 11, and lower intensity of band 13 were observed in the summer group compared to the winter group. In 2-DE profiles of camel tears, four protein spots were found expressed differentially in two seasons. Further protein identification by MALDI-TOF/TOF-MS and confirmation by western blotting indicated that there was a significant decrease in LF (p=0.002) and an increase in VMO1 homolog (p=0.042) in tears in the summer compared to the winter. Conclusions The seasonal variation of camel tear fluids has been found in the composition of proteins, including LF and VMO1 homolog. This result will expand our knowledge of physiologic characteristics of tear fluids and establish a foundation for the mechanistic studies and clinical practices on ocular surface disorders. PMID:21293736

  16. Impact of winter roads on boreal peatland carbon exchange.

    PubMed

    Strack, Maria; Softa, Divya; Bird, Melanie; Xu, Bin

    2018-01-01

    Across Canada's boreal forest, linear disturbances, including cutlines such as seismic lines and roads, crisscross the landscape to facilitate resource exploration and extraction; many of these linear disturbances cross peatland ecosystems. Changes in tree canopy cover and the compression of the peat by heavy equipment alter local thermal, hydrological, and ecological conditions, likely changing carbon exchange on the disturbance, and possibly in the adjacent peatland. We measured bulk density, water table, soil temperature, plant cover, and CO 2 and CH 4 flux along triplicate transects crossing a winter road through a wooded fen near Peace River, Alberta, Canada. Sample plots were located 1, 5, and 10 m from the road on both sides with an additional three plots on the road. Productivity of the overstory trees, when present, was also determined. The winter road had higher bulk density, shallower water table, higher graminoid cover, and thawed earlier than the adjacent peatland. Tree productivity and CO 2 flux varied between the plots, and there was no clear pattern in relation to distance from the road. The plots on the winter road acted as a greater CO 2 sink and greater CH 4 source compared to the adjacent peatland with plots on the winter road emitting on average (standard error) 479 (138) compared to 41 (10) mg CH 4  m -2  day -1 in the adjacent peatland. Considering both gases, global warming potential increased from 70 to 250 g CO 2 e m -2  year -1 in the undisturbed area to 2100 g CO 2 e m -2  year -1 on the winter road. Although carbon fluxes on any given cutline through peatland will vary depending on level of compaction, line width and vegetation community shifts, the large number of linear disturbances in Canada's boreal forest and slow recovery on peatland ecosites suggest they could represent an important anthropogenic greenhouse gas source. © 2017 John Wiley & Sons Ltd.

  17. Cold truths: how winter drives responses of terrestrial organisms to climate change.

    PubMed

    Williams, Caroline M; Henry, Hugh A L; Sinclair, Brent J

    2015-02-01

    Winter is a key driver of individual performance, community composition, and ecological interactions in terrestrial habitats. Although climate change research tends to focus on performance in the growing season, climate change is also modifying winter conditions rapidly. Changes to winter temperatures, the variability of winter conditions, and winter snow cover can interact to induce cold injury, alter energy and water balance, advance or retard phenology, and modify community interactions. Species vary in their susceptibility to these winter drivers, hampering efforts to predict biological responses to climate change. Existing frameworks for predicting the impacts of climate change do not incorporate the complexity of organismal responses to winter. Here, we synthesise organismal responses to winter climate change, and use this synthesis to build a framework to predict exposure and sensitivity to negative impacts. This framework can be used to estimate the vulnerability of species to winter climate change. We describe the importance of relationships between winter conditions and performance during the growing season in determining fitness, and demonstrate how summer and winter processes are linked. Incorporating winter into current models will require concerted effort from theoreticians and empiricists, and the expansion of current growing-season studies to incorporate winter. © 2014 The Authors. Biological Reviews © 2014 Cambridge Philosophical Society.

  18. Increasing aeolian dust deposition to snowpacks in the Rocky Mountains inferred from snowpack, wet deposition, and aerosol chemistry

    USGS Publications Warehouse

    Clow, David W.; Williams, Mark W.; Schuster, Paul F.

    2016-01-01

    Mountain snowpacks are a vital natural resource for ∼1.5 billion people in the northern Hemisphere, helping to meet human and ecological demand for water in excess of that provided by summer rain. Springtime warming and aeolian dust deposition accelerate snowmelt, increasing the risk of water shortages during late summer, when demand is greatest. While climate networks provide data that can be used to evaluate the effect of warming on snowpack resources, there are no established regional networks for monitoring aeolian dust deposition to snow. In this study, we test the hypothesis that chemistry of snow, wet deposition, and aerosols can be used as a surrogate for dust deposition to snow. We then analyze spatial patterns and temporal trends in inferred springtime dust deposition to snow across the Rocky Mountains, USA, for 1993–2014. Geochemical evidence, including strong correlations (r2 ≥ 0.94) between Ca2+, alkalinity, and dust concentrations in snow deposited during dust events, indicate that carbonate minerals in dust impart a strong chemical signature that can be used to track dust deposition to snow. Spatial patterns in chemistry of snow, wet deposition, and aerosols indicate that dust deposition increases from north to south in the Rocky Mountains, and temporal trends indicate that winter/spring dust deposition increased by 81% in the southern Rockies during 1993–2014. Using a multivariate modeling approach, we determined that increases in dust deposition and decreases in springtime snowfall combined to accelerate snowmelt timing in the southern Rockies by approximately 7–18 days between 1993 and 2014. Previous studies have shown that aeolian dust emissions may have doubled globally during the 20th century, possibly due to drought and land-use change. Climate projections for increased aridity in the southwestern U.S., northern Africa, and other mid-latitude regions of the northern Hemisphere suggest that aeolian dust emissions may continue to

  19. Photosynthetic capacity of red spruce during winter

    Treesearch

    P.G. Schaberg; J.B. Shane; P.F. Cali; J.R. Donnelly; G.R. Strimbeck

    1998-01-01

    We measured the photosynthetic capacity (Pmax) of plantation-grown red spruce (Picea rubens Sarg.) during two winter seasons (1993-94 and 1994-95) and monitored field photosynthesis of these trees during one winter (1993-94). We also measured Pmax for mature montane trees from January through May 1995....

  20. 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.

  1. Conserving and managing the subnivium.

    PubMed

    Zuckerberg, Benjamin; Pauli, Jonathan N

    2018-02-08

    In regions where snowfall historically has been a defining seasonal characteristic of the landscape, warming winters have reduced the depth, duration, and extent of snowpack. However, most management and conservation has focused on how aboveground wildlife will be affected by altered snow conditions, even though the majority of species that persist through the winter do so under the snowpack in a thermally stable refugium: the subnivium. Shortened winters, forest management practices, and winter recreation can alter subnivium conditions by increasing snow compaction and compromising thermal stability at the soil-snow interface. To help slow the loss of the subnivium in the face of rapidly changing winter conditions, we suggest managers adopt regional conservation plans for identifying threatened snow-covered environments; measure and predict the effects land cover and habitat management has on local subnivium conditions; and control the timing and distribution of activities that disturb and compact snow cover (e.g., silvicultural practices, snow recreation, and road and trail maintenance). As a case study, we developed a spatially explicit model of subnivium presence in a working landscape of the Chequamegon National Forest, Wisconsin. We identified landscapes where winter recreation and management practices could threaten potentially important areas for subnivium persistence. Similar modeling approaches could inform management decisions related to subnivium conservation. Current climate projections predict that snow seasons will change rapidly in many regions, and as result, we advocate for the immediate recognition, conservation, and management of the subnivium and its dependent species. © 2018 Society for Conservation Biology.

  2. 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

  3. Soil aggregates and their associated carbon and nitrogen content in winter annual pastures using different tillage management options

    USDA-ARS?s Scientific Manuscript database

    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...

  4. Glucose Content and In Vitro Bioaccessibility in Sweet Potato and Winter Squash Varieties during Storage

    PubMed Central

    Zaccari, Fernanda; Cabrera, María Cristina; Saadoun, Ali

    2017-01-01

    Glucose content and in vitro bioaccessibility were determined in raw and cooked pulp of Arapey, Cuabé, and Beauregard sweet potato varieties, as well as Maravilla del Mercado and Atlas winter squash, after zero, two, four, and six months of storage (14 °C, 80% relative humidity (RH)). The total glucose content in 100 g of raw pulp was, for Arapey, 17.7 g; Beauregard, 13.2 g; Cuabé, 12.6 g; Atlas, 4.0 g; and in Maravilla del Mercado, 4.1 g. These contents were reduced by cooking process and storage time, 1.1 to 1.5 times, respectively, depending on the sweet potato variety. In winter squash varieties, the total glucose content was not modified by cooking, while the storage increased glucose content 2.8 times in the second month. After in vitro digestion, the glucose content released was 7.0 times higher in sweet potato (6.4 g) than in winter squash (0.91 g) varieties. Glucose released by in vitro digestion for sweet potato stored for six months did not change, but in winter squashes, stored Atlas released glucose content increased 1.6 times. In conclusion, in sweet potato and winter squash, the glucose content and the released glucose during digestive simulation depends on the variety and the storage time. These factors strongly affect the supply of glucose for human nutrition and should be taken into account for adjusting a diet according to consumer needs. PMID:28665302

  5. Glucose Content and In Vitro Bioaccessibility in Sweet Potato and Winter Squash Varieties during Storage.

    PubMed

    Zaccari, Fernanda; Cabrera, María Cristina; Saadoun, Ali

    2017-06-30

    Glucose content and in vitro bioaccessibility were determined in raw and cooked pulp of Arapey, Cuabé, and Beauregard sweet potato varieties, as well as Maravilla del Mercado and Atlas winter squash, after zero, two, four, and six months of storage (14 °C, 80% relative humidity (RH)). The total glucose content in 100 g of raw pulp was, for Arapey, 17.7 g; Beauregard, 13.2 g; Cuabé, 12.6 g; Atlas, 4.0 g; and in Maravilla del Mercado, 4.1 g. These contents were reduced by cooking process and storage time, 1.1 to 1.5 times, respectively, depending on the sweet potato variety. In winter squash varieties, the total glucose content was not modified by cooking, while the storage increased glucose content 2.8 times in the second month. After in vitro digestion, the glucose content released was 7.0 times higher in sweet potato (6.4 g) than in winter squash (0.91 g) varieties. Glucose released by in vitro digestion for sweet potato stored for six months did not change, but in winter squashes, stored Atlas released glucose content increased 1.6 times. In conclusion, in sweet potato and winter squash, the glucose content and the released glucose during digestive simulation depends on the variety and the storage time. These factors strongly affect the supply of glucose for human nutrition and should be taken into account for adjusting a diet according to consumer needs.

  6. [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.

  7. Mixotrophy in Heterocapsa rotundata: A Mechanism for Dominating the Winter Phytoplankton Community

    NASA Astrophysics Data System (ADS)

    Millette, N.; Pierson, J. J.; Aceves, A.; Stoecker, D.

    2016-02-01

    Heterocapsa rotundata is a dinoflagellate that forms large winter blooms in estuaries and coastal ecosystems. Past research has focused on the mechanisms necessary for these winter blooms to form but it is unknown why H. rotundata consistently forms these blooms. H. rotundata is a known mixotroph, and we conducted grazing experiments with a non-axenic culture of H. rotundata containing bacteria to test what environmental conditions increase H. rotundata's community grazing rate. We used microspheres to confirm that H. rotundata was grazing. We measured the change of bacterial abundance in control (without grazers) and experimental groups over 24 hours to estimate H. rotundata's community grazing rate on bacteria at different irradiance levels and ammonium concentrations. There was a significant interaction between the effect of ammonium concentration and irradiance levels. As irradiance levels decreased, the effect of ammonium concentrations on H. rotundata grazing rates became less pronounced. At lower irradiance levels H. rotundata grazing rates remained high, regardless of the ammonium concentration. Overall, changes in irradiance levels had a larger impact on H. rotundata grazing rates than changes in ammonium concentration. The findings will be discussed in light of ongoing lab and field research. The winter season is known for limiting light levels that most likely have a negative impact on phytoplankton growth rates. Heterocapsa rotundata has adapted to low light levels by increasing grazing on bacteria to consume enough carbon to maintain growth. Heterocapsa rotundata's response to low light levels is likely the mechanism that provides the competitive advantage to form winter blooms under the right conditions over other phytoplankton species.

  8. Combined use of Landsat-8 and Sentinel-2A images for winter crop mapping and winter wheat yield assessment at regional scale

    PubMed Central

    Skakun, Sergii; Vermote, Eric; Roger, Jean-Claude; Franch, Belen

    2018-01-01

    Timely and accurate information on crop yield is critical to many applications within agriculture monitoring. Thanks to its coverage and temporal resolution, coarse spatial resolution satellite imagery has always been a source of valuable information for yield forecasting and assessment at national and regional scales. With availability of free images acquired by Landsat-8 and Sentinel-2 remote sensing satellites, it becomes possible to enable temporal resolution of an image every 3–5 days, and therefore, to develop next generation agriculture products at higher spatial resolution (30 m). This paper explores the combined use of Landsat-8 and Sentinel-2A for winter crop mapping and winter wheat assessment at regional scale. For the former, we adapt a previously developed approach for Moderate Resolution Imaging Spectroradiometer (MODIS) at 250 m resolution that allows automatic mapping of winter crops taking into account knowledge on crop calendar and without ground truth data. For the latter, we use a generalized winter wheat yield model that is based on NDVI-peak estimation and MODIS data, and further downscaled to be applicable at 30 m resolution. We show that integration of Landsat-8 and Sentinel-2A has a positive impact both for winter crop mapping and winter wheat yield assessment. In particular, the error of winter wheat yield estimates can be reduced up to 1.8 times comparing to the single satellite usage. PMID:29888751

  9. Combined Use of Landsat-8 and Sentinel-2A Images for Winter Crop Mapping and Winter Wheat Yield Assessment at Regional Scale

    NASA Technical Reports Server (NTRS)

    Skakun, Sergii; Vermote, Eric; Roger, Jean-Claude; Franch, Belen

    2017-01-01

    Timely and accurate information on crop yield and production is critical to many applications within agriculture monitoring. Thanks to its coverage and temporal resolution, coarse spatial resolution satellite imagery has always been a source of valuable information for yield forecasting and assessment at national and regional scales. With availability of free images acquired by Landsat-8 and Sentinel-2 remote sensing satellites, it becomes possible to provide temporal resolution of an image every 3-5 days, and therefore, to develop next generation agriculture products at higher spatial resolution (10-30 m). This paper explores the combined use of Landsat-8 and Sentinel-2A for winter crop mapping and winter wheat yield assessment at regional scale. For the former, we adapt a previously developed approach for the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument at 250 m resolution that allows automatic mapping of winter crops taking into account a priori knowledge on crop calendar. For the latter, we use a generalized winter wheat yield forecasting model that is based on estimation of the peak Normalized Difference Vegetation Index (NDVI) from MODIS image time-series, and further downscaled to be applicable at 30 m resolution. We show that integration of Landsat-8 and Sentinel-2A improves both winter crop mapping and winter wheat yield assessment. In particular, the error of winter wheat yield estimates can be reduced up to 1.8 times compared to using a single satellite.

  10. Economic Evaluation of Advanced Winter Highway Maintenance Strategies

    DOT National Transportation Integrated Search

    1998-01-01

    Highway agencies face demands to maintain or improve the existing winter roadway level of service. This paper examines the potential benefits of applying advanced winter highway maintenance strategies. The Vermont Agency of Transportation conducted "...

  11. Comparison of winter wheat yield sensitivity to climate variables under irrigated and rain-fed conditions

    NASA Astrophysics Data System (ADS)

    Xiao, Dengpan; Shen, Yanjun; Zhang, He; Moiwo, Juana P.; Qi, Yongqing; Wang, Rende; Pei, Hongwei; Zhang, Yucui; Shen, Huitao

    2016-09-01

    Crop simulation models provide alternative, less time-consuming, and cost-effective means of determining the sensitivity of crop yield to climate change. In this study, two dynamic mechanistic models, CERES (Crop Environment Resource Synthesis) and APSIM (Agricultural Production Systems Simulator), were used to simulate the yield of wheat ( Triticum aestivum L.) under well irrigated (CFG) and rain-fed (YY) conditions in relation to different climate variables in the North China Plain (NCP). The study tested winter wheat yield sensitivity to different levels of temperature, radiation, precipitation, and atmospheric carbon dioxide (CO2) concentration under CFG and YY conditions at Luancheng Agro-ecosystem Experimental Stations in the NCP. The results from the CERES and APSIM wheat crop models were largely consistent and suggested that changes in climate variables influenced wheat grain yield in the NCP. There was also significant variation in the sensitivity of winter wheat yield to climate variables under different water (CFG and YY) conditions. While a temperature increase of 2°C was the threshold beyond which temperature negatively influenced wheat yield under CFG, a temperature rise exceeding 1°C decreased winter wheat grain yield under YY. A decrease in solar radiation decreased wheat grain yield under both CFG and YY conditions. Although the sensitivity of winter wheat yield to precipitation was small under the CFG, yield decreased significantly with decreasing precipitation under the rainfed YY treatment. The results also suggest that wheat yield under CFG linearly increased by ≈3.5% per 60 ppm (parts per million) increase in CO2 concentration from 380 to 560 ppm, and yield under YY increased linearly by ≈7.0% for the same increase in CO2 concentration.

  12. Coupled Effects of Climatic and Socio-economic Factors on Winter Cropping in India

    NASA Astrophysics Data System (ADS)

    Jain, M.; Mondal, P.; Galford, G. L.; DeFries, R. S.

    2015-12-01

    India is predicted to be one of the most vulnerable regions in terms of agricultural sensitivity to future climate changes. Approximately 69% of India's population is rural, and over 55% of the working population relies on agriculture for sustenance and livelihoods. Indian smallholder farmers who own less than 2 ha of farmland represent 78% of the total Indian farmers and produce 41% of the country's food crops. These smallholder farmers are among some of the most vulnerable communities to climatic and economic changes due to limited access to technology, infrastructure, markets, and institutional or financial support in the case of adverse climatic events. Baseline information on agricultural sensitivity to climate variability will provide useful information for regional-level, and eventually state- and national-level, strategies and policies that promote adaption to climate variability. We use a decade of remote sensing analysis of cropping patterns and climatic factors along with census data for irrigation and demographic factors to understand winter cropping trajectories across agro-ecological zones in India. Findings from multiple agro-ecological zones indicate that there are three primary trajectories in winter cropping in India - increasing, fluctuating, and decreasing. In the Central Indian Highlands, for example, the most dominant trend is that of fluctuating cropped area, ranging between ~37,300 km2 in 2010 and ~21,100 km2 in 2013, which is associated with village-level access to irrigation and local labor dynamics. Clay soil type and increasing irrigation coverage were associated with intensification. Yet, suitable soil type and access to irrigation do not reduce vulnerability to high daytime temperatures that is negatively associated with winter crop cover. With pronounced winter warming projected in the coming decades, effective adaptation by smallholder farmers would require additional strategies, such as access to fine-scale temperature forecasts

  13. Observations of the Winter Thermal Structure of Lake Superior

    NASA Astrophysics Data System (ADS)

    Titze, Daniel James

    Moored thermistor strings that span the water column have been deployed at up to seven locations throughout Lake Superior from 2005 through present, producing a unique year-round record of the thermal structure of a large lake. This extensive temperature record reveals significant interannual and spatial variability in Lake Superior's winter heat content, thermocline depth, and phenology. Of particular mention is a stark contrast in thermal structure between the cold, icy winter of 2009 and the much warmer winter of 2012, during which especially strong and weak negative stratification was observed, respectively. Significant interannual and spatial variability was also observed in Lake Superior ice cover, as shown through data extracted from Ice Mapping System satellite imagery (NOAA/NESDIS 2004). When water column heat content was estimated from temperature data and analyzed in concert with lake ice-cover data, it was found that ice cover can inhibit heat flux between the lake and the atmosphere, and that spatial variability in ice cover can translate into spatial variability in end-of-winter heat content. Such variability in end-of-winter heat content is found to be preserved through the spring warming season, and is strongly correlated with variability in the timing of the onset of summer stratification, with regions that have warmer end-of-winter water columns stratifying earlier than regions with colder end-of-winter water-columns.

  14. 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.

  15. Important fossil source contribution to brown carbon in Beijing during winter

    NASA Astrophysics Data System (ADS)

    Yan, Caiqing; Zheng, Mei; Bosch, Carme; Andersson, August; Desyaterik, Yury; Sullivan, Amy P.; Collett, Jeffrey L.; Zhao, Bin; Wang, Shuxiao; He, Kebin; Gustafsson, Örjan

    2017-03-01

    Organic aerosol (OA) constitutes a substantial fraction of fine particles and affects both human health and climate. It is becoming clear that OA absorbs light substantially (hence termed Brown Carbon, BrC), adding uncertainties to global aerosol radiative forcing estimations. The few current radiative-transfer and chemical-transport models that include BrC primarily consider sources from biogenic and biomass combustion. However, radiocarbon fingerprinting here clearly indicates that light-absorbing organic carbon in winter Beijing, the capital of China, is mainly due to fossil sources, which contribute the largest part to organic carbon (OC, 67 ± 3%) and its sub-constituents (water-soluble OC, WSOC: 54 ± 4%, and water-insoluble OC, WIOC: 73 ± 3%). The dual-isotope (Δ14C/δ13C) signatures, organic molecular tracers and Beijing-tailored emission inventory identify that this fossil source is primarily from coal combustion activities in winter, especially from the residential sector. Source testing on Chinese residential coal combustion provides direct evidence that intensive coal combustion could contribute to increased light-absorptivity of ambient BrC in Beijing winter. Coal combustion is an important source to BrC in regions such as northern China, especially during the winter season. Future modeling of OA radiative forcing should consider the importance of both biomass and fossil sources.

  16. Important fossil source contribution to brown carbon in Beijing during winter

    PubMed Central

    Yan, Caiqing; Zheng, Mei; Bosch, Carme; Andersson, August; Desyaterik, Yury; Sullivan, Amy P.; Collett, Jeffrey L.; Zhao, Bin; Wang, Shuxiao; He, Kebin; Gustafsson, Örjan

    2017-01-01

    Organic aerosol (OA) constitutes a substantial fraction of fine particles and affects both human health and climate. It is becoming clear that OA absorbs light substantially (hence termed Brown Carbon, BrC), adding uncertainties to global aerosol radiative forcing estimations. The few current radiative-transfer and chemical-transport models that include BrC primarily consider sources from biogenic and biomass combustion. However, radiocarbon fingerprinting here clearly indicates that light-absorbing organic carbon in winter Beijing, the capital of China, is mainly due to fossil sources, which contribute the largest part to organic carbon (OC, 67 ± 3%) and its sub-constituents (water-soluble OC, WSOC: 54 ± 4%, and water-insoluble OC, WIOC: 73 ± 3%). The dual-isotope (Δ14C/δ13C) signatures, organic molecular tracers and Beijing-tailored emission inventory identify that this fossil source is primarily from coal combustion activities in winter, especially from the residential sector. Source testing on Chinese residential coal combustion provides direct evidence that intensive coal combustion could contribute to increased light-absorptivity of ambient BrC in Beijing winter. Coal combustion is an important source to BrC in regions such as northern China, especially during the winter season. Future modeling of OA radiative forcing should consider the importance of both biomass and fossil sources. PMID:28266611

  17. 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

  18. Hygiene at winter bird feeders in a southwestern Ontario city.

    PubMed Central

    Prescott, J F; Hunter, D B; Campbell, G D

    2000-01-01

    To further understand the source of the epidemic of salmonellosis in some species of birds using bird feeders in southern Ontario in the winter of 1997-1998, 124 bird feeder stations were examined for their state of hygiene and for Salmonella on 5 occasions during the winter of 1999 in a city of 100,000 people in southwestern Ontario. No Salmonella were isolated from feed contaminated with feces recovered from the feeders. Squirrel-proof feeders were significantly less contaminated with feces than were other feeder types (hopper, platform, silo), which did not differ significantly in their hygiene scores. Contamination of squirrel-proof feeders increased significantly through the course of the study, but other feeder types showed no significant change. Hygiene was poorer if feeders were maintained equally by both male and female household members, particularly as they grew older, but no age or gender effect was observed if only one person was largely responsible for maintaining the feeders. We concluded that winter bird feeder stations in a southern Ontario city were not contaminated with Salmonella but that bird feeder stations could be designed better to reduce fecal contamination of feed. PMID:10992987

  19. Ecological impacts of winter water level drawdowns on lake littoral zones: A review

    USGS Publications Warehouse

    Roy, Allison

    2017-01-01

    Freshwater littoral zones harbor diverse ecological communities and serve numerous ecosystem functions that are controlled, in part, by natural water level fluctuations. However, human alteration of lake hydrologic regimes beyond natural fluctuations threaten littoral zone ecological integrity. One type of hydrologic alteration in lakes is winter water level drawdowns, which are frequently employed for hydropower, flood control, and macrophyte control, among other purposes. Here, we synthesize the abiotic and biotic responses to annual and novel winter water level drawdowns in littoral zones of lakes and reservoirs. The dewatering, freezing, and increased erosion of exposed lakebeds drive changes in the littoral zone. Shoreline-specific physicochemical conditions such as littoral slope and shoreline exposure further induce modifications. Loss of fine sediment decreases nutrient availability over time, but desiccation may promote a temporary nutrient pulse upon re-inundation. Annual winter drawdowns can decrease taxonomic richness of macrophytes and benthic invertebrates and shift assemblage composition to favor taxa with r-selected life history strategies and with functional traits resistant to direct and indirect drawdown effects. Fish assemblages, though less directly affected by winter drawdowns (except where there is critically low dissolved oxygen), experience negative effects via indirect pathways like decreased food resources and spawning habitat. We identify eight general research gaps to guide future research that could improve our understanding about the complex effects of winter drawdowns on littoral zone ecology.

  20. Wintering bald eagle trends in northern Arizona, 1975-2000

    Treesearch

    Teryl G. Grubb

    2003-01-01

    Between 1975 and 2000, 4,525 sightings of wintering bald eagles (Haliaeetus leucocephalus) were recorded at Mormon Lake in northern Arizona. Numbers of wintering eagles fluctuated little in the 20 years from 1975 through 1994 (5.5 ± 3.0 mean sightings per day). However, during the winters of 1995 through 1997 local record highs of 59 to 118 eagles...

  1. [Effects of irrigation using dairy effluent on grain yield, phosphorus utilization and distribu- tion in soil profile in winter wheat-summer maize rotation system].

    PubMed

    Du, Hui-ying; Feng, Jie; Guo, Hai-gang; Wang, Feng; Zhang, Ke-qiang

    2015-08-01

    Field experiments of winter wheat-summer maize rotation were conducted in North China Plain irrigation area to explore the effects of wheat season irrigation with dairy effluent on grain yield, phosphorus uptake, accumulative phosphorus usage efficiency and phosphorus accumulation in soil. The results showed that the irrigation with dairy effluent significantly improved the yields of winter wheat and summer maize. With the increasing of P2O5 carried by dairy effluent into soil, winter wheat yield increased at first and then decreased. When the P2O5 increased 137 kg · hm(-2), winter wheat yield increased to the maximum (7646.4 kg · hm(-2)) and the phosphorus utilization rate was the highest (24.8%). But excessive phosphorus decreased the winter wheat yield and phosphorus utilization efficiency. Summer maize yield and phosphorus uptake increased with the increase of P2O5 carried by dairy effluent. The summer maize yield increased by 2222.4-2628.6 kg · hm(-2) and the phosphorus uptake increased by 13.9-21.1 kg · hm(-2) in contrast to the control (CK). Under conventional phosphorus fertilization at 88 kg · hm(-2), and the summer maize yield increased by 2235.0 kg · hm(-2) compared with CK. As the time of irrigation with dairy effluent increasing, the grain yield increased more significantly. The cumulative phosphorus utilization in this rotation system increased year by year. After six seasons of crop harvest, the cumulative phosphorus utilization rate increased into 40.0%-47.7%. Under the experimental condition, two times of irrigation with the dairy effluents in the winter wheat-summer maize rotation system was the best operating mode.

  2. Snow Based Winter Tourism and Kinds of Adaptations to Climate Change

    NASA Astrophysics Data System (ADS)

    Breiling, M.

    2009-04-01

    Austria is the most intensive winter tourism country in the world with some 4% contribution in the national GNP. Snow based winter tourism became the lead economy of mountain areas, covering two thirds of the country and is by far economically more important than agriculture and forestry. While natural snow was the precondition for the establishment of winter tourism, artificial snow is nowadays the precondition to maintain winter tourism in the current economic intensity. Skiing originally low tech, is developing increasingly into high tech. While skiing was comparatively cheap in previous days due to natural snow, skiing is getting more expensive and exclusive for a higher income class due to the relative high production costs. Measures to adapt to a warmer climate can be divided into three principle types: physical adaptation, technical adaptation - where artificial snow production plays a major role - and social adaptation. It will be discussed under which conditions each adaptation type seems feasible in dependence of the level of warming. In particular physical and technical adaptations are related to major investments. Practically every ski resort has to decide about what is an appropriate, economically cost efficient level of adaptation. Adapting too much reduces profits. Adapting too little does not bring enough income. The optimal level is often not clear. In many cases public subsidies help to collect funds for adaptation and to keep skiing profitable. The possibility to adapt on local, regional or on national scales will depend on the degree of warming, the future price of artificial snow production and the public means foreseen to support the winter tourism industry.

  3. 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

  4. Economic Evaluation of Advanced Winter Highway Maintenance Strategies

    DOT National Transportation Integrated Search

    1988-01-01

    Highway agencies face demands to maintain or improve the existing winter roadway level of service. The benefits of advanced winter highway maintenance strategies now become more attractive. This paper examines the potential benefits of applying advan...

  5. Downtown People Mover (DPM) Winterization Test Demonstration : Westinghouse

    DOT National Transportation Integrated Search

    1982-01-01

    The Westinghouse Downtown People Mover (DPM) Winterization Test Demonstration (WTD) Final Report covers the 1978-79 and 1979-80 winter periods. Tests were performed at the Westinghouse Transportation Division (WTD) test track located in Pittsburgh, P...

  6. Economic evaluation of advanced winter highway maintenance strategies

    DOT National Transportation Integrated Search

    1998-08-19

    Highway agencies face demands to maintain or improve the existing winter roadway level of service. The benefits of advanced winter highway maintenance strategies now become more attractive. This paper examines the potential benefits of applying advan...

  7. Numerical simulation of a rare winter hailstorm event over Delhi, India on 17 January 2013

    NASA Astrophysics Data System (ADS)

    Chevuturi, A.; Dimri, A. P.; Gunturu, U. B.

    2014-12-01

    This study analyzes the cause of the rare occurrence of a winter hailstorm over New Delhi/NCR (National Capital Region), India. The absence of increased surface temperature or low level of moisture incursion during winter cannot generate the deep convection required for sustaining a hailstorm. Consequently, NCR shows very few cases of hailstorms in the months of December-January-February, making the winter hail formation a question of interest. For this study, a recent winter hailstorm event on 17 January 2013 (16:00-18:00 UTC) occurring over NCR is investigated. The storm is simulated using the Weather Research and Forecasting (WRF) model with the Goddard Cumulus Ensemble (GCE) microphysics scheme with two different options: hail and graupel. The aim of the study is to understand and describe the cause of hailstorm event during over NCR with a comparative analysis of the two options of GCE microphysics. Upon evaluating the model simulations, it is observed that the hail option shows a more similar precipitation intensity with the Tropical Rainfall Measuring Mission (TRMM) observation than the graupel option does, and it is able to simulate hail precipitation. Using the model-simulated output with the hail option; detailed investigation on understanding the dynamics of hailstorm is performed. The analysis based on a numerical simulation suggests that the deep instability in the atmospheric column led to the formation of hailstones as the cloud formation reached up to the glaciated zone promoting ice nucleation. In winters, such instability conditions rarely form due to low level available potential energy and moisture incursion along with upper level baroclinic instability due to the presence of a western disturbance (WD). Such rare positioning is found to be lowering the tropopause with increased temperature gradient, leading to winter hailstorm formation.

  8. Frequent arousals from winter torpor in Rafinesque's big-eared bat (Corynorhinus rafinesquii).

    PubMed

    Johnson, Joseph S; Lacki, Michael J; Thomas, Steven C; Grider, John F

    2012-01-01

    Extensive use of torpor is a common winter survival strategy among bats; however, data comparing various torpor behaviors among species are scarce. Winter torpor behaviors are likely to vary among species with different physiologies and species inhabiting different regional climates. Understanding these differences may be important in identifying differing susceptibilities of species to white-nose syndrome (WNS) in North America. We fitted 24 Rafinesque's big-eared bats (Corynorhinus rafinesquii) with temperature-sensitive radio-transmitters, and monitored 128 PIT-tagged big-eared bats, during the winter months of 2010 to 2012. We tested the hypothesis that Rafinesque's big-eared bats use torpor less often than values reported for other North American cave-hibernators. Additionally, we tested the hypothesis that Rafinesque's big-eared bats arouse on winter nights more suitable for nocturnal foraging. Radio-tagged bats used short (2.4 d ± 0.3 (SE)), shallow (13.9°C ± 0.6) torpor bouts and switched roosts every 4.1 d ± 0.6. Probability of arousal from torpor increased linearly with ambient temperature at sunset (P<0.0001), and 83% (n=86) of arousals occurred within 1 hr of sunset. Activity of PIT-tagged bats at an artificial maternity/hibernaculum roost between November and March was positively correlated with ambient temperature at sunset (P<0.0001), with males more active at the roost than females. These data show Rafinesque's big-eared bat is a shallow hibernator and is relatively active during winter. We hypothesize that winter activity patterns provide Corynorhinus species with an ecological and physiological defense against the fungus causing WNS, and that these bats may be better suited to withstand fungal infection than other cave-hibernating bat species in eastern North America.

  9. NASA Sees Winter Storm Slamming Eastern United States

    NASA Image and Video Library

    2017-12-08

    NASA satellite imagery captured the size of the massive winter storm that continued to pummel the U.S. East Coast early on January 23, 2016. This visible image of the major winter storm was taken from NOAA's GOES-East satellite on Saturday, January 23, 2016 at 1437 UTC (9:37 a.m. EST) as the Baltimore/Washington corridor was under a blizzard warning. Read more: go.nasa.gov/1RFv70u Credits: NASA/NOAA GOES Project NASA Sees Winter Storm Slamming Eastern United States

  10. 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…

  11. Experimental research on the poly-aluminum chloride for treating the Pi River water in winter and summer

    NASA Astrophysics Data System (ADS)

    Jia, Rusheng; Bai, Yulin; Yang, Jie

    2018-02-01

    In the beaker experiments that the disposal of low turbidity water, we observed the influence of some factors, such as the dosage of poly-aluminum chloride coagulant, the pH value of raw water, in disposing the high natural organic matters of low turbidity water in winter and summer. we discussed the removal of residual aluminum and UV254 in summer. The experimental results show that when the turbidity is less than 10 NTU, the optimum dosage are 14.4 mg.L-1 and 8.2 mg.L-1 respectively in winter and summer. No matter in winter or summer, the effect of pH value on coagulation treatment is very significant, the best pH value is about 8.1. In summer, with the increase of dosage of poly-aluminum chloride, residual aluminum increased slowly after decrease, turbidity and UV254 after precipitation is similar removal trend. Finally, according to the current market price of poly-aluminum chloride economic analysis, daily differences in pharmaceutical costs about 1600 yuan in summer and winter in the second water plant in Lu’an.

  12. Metabolic response to lipid infusion in fasting winter-acclimatized king penguin chicks (Aptenodytes patagonicus).

    PubMed

    Teulier, Loïc; Tornos, Jérémy; Rouanet, Jean-Louis; Rey, Benjamin; Roussel, Damien

    2013-05-01

    During the cold austral winter, king penguin chicks are infrequently fed by their parents and thus experience severe nutritional deprivation under harsh environmental conditions. These energetic constraints lead to a range of energy sparing mechanisms balanced by the maintenance of efficient thermogenic processes. The present work investigated whether the high thermogenic capacities exhibited by winter-acclimatized king penguin chicks could be related to an increase in lipid substrate supply and oxidation in skeletal muscle, the main site of thermogenesis in birds. To test this hypothesis, we examined i) the effect of an experimental rise in plasma triglyceride on the whole metabolic rate in winter-acclimatized (WA) and de-acclimatized king penguin chicks kept at thermoneutrality (TN), and ii) investigated the fuel preference of muscle mitochondria. In vivo, a perfusion of a lipid emulsion induced a small 10% increase of metabolic rate in WA chicks but not in TN group. In vitro, the oxidation rate of muscle mitochondria respiring on lipid-derived substrate was +40% higher in WA chicks than in TN, while no differences were found between groups when mitochondria oxidized carbohydrate-derived substrate or succinate. Despite an enhanced fuel selection towards lipid oxidation in skeletal muscle, a rise of circulating lipids per se was not sufficient to fully unravel the thermogenic capacity of winter-acclimatized king penguin chicks. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Is it possible that a gravity increase of 20 μGal yr-1 in southern Tibet comes from a wide-range density increase?

    NASA Astrophysics Data System (ADS)

    Yi, Shuang; Wang, Qiuyu; Sun, Wenke

    2016-02-01

    With absolute gravimetric observations from 2010 to 2013 in the southern Tibet, Chen et al. (2016) reported a gravity increase of up to 20 μGal/yr and concluded that it is possible if there was a density increase in a disk range of 580 km in diameter. Here we used observations from the gravity satellites Gravity Recovery and Climate Experiment (GRACE) over 12 years to evaluate whether the model was practical, because a mass accumulation in such a large spatial range is well within the detectability ability of GRACE. The gravity trend based on their model is orders of magnitude larger than the GRACE observation, thus negating its conclusions. We then evaluated contributions from seasonal variation, lakes, glaciers, rivers, precipitation, and snowfall and concluded that these factors cannot cause such a large gravity signal. Finally, we discussed some possible explanations for the gravity increase of 40 μGal in two years.

  14. PMP-1 Report: the Fourth Winter of PMP-1, 1981 - 1982: a Winter with Several Interesting Features

    NASA Technical Reports Server (NTRS)

    Labitzke, K.

    1982-01-01

    A synoptic description is given for the fourth winter of pre-MAP project 1 (PMP-1), 1981/82. The main characteristics of this winter are a Canadian warming in the beginning of December, a very strong minor warming in January, and an early final warming in mid-March. The eddy momentum budget, calculated from the daily height and temperature charts, is discussed in terms of the divergence of the Eliassen-Palm-vector.

  15. Effects of imidacloprid and clothianidin seed treatments on wheat aphids and their natural enemies on winter wheat.

    PubMed

    Zhang, Peng; Zhang, Xuefeng; Zhao, Yunhe; Wei, Yan; Mu, Wei; Liu, Feng

    2016-06-01

    Wheat aphid (Hemiptera: Aphididae) is one of the major pests of winter wheat and has posed a significant threat to winter wheat production in China. Although neonicotinoid insecticidal seed treatments have been suggested to be a control method, the season-long efficacy on pests and the impact on their natural enemies are still uncertain. Experiments were conducted to determine the efficacy of imidacloprid and clothianidin on the control of aphids, the number of their natural enemies and the emergence rate and yield of wheat during 2011-2014. Imidacloprid and clothianidin seed treatments had no effect on the emergence rate of winter wheat and could prevent yield losses and wheat aphid infestations throughout the winter wheat growing season. Furthermore, their active ingredients were detected in winter wheat leaves up to 200 days after sowing. Imidacloprid and clothianidin seed treatments had no adverse effects on ladybirds, hoverflies or parasitoids, and instead increased the spider-aphid ratios. Wheat seeds treated with imidacloprid and clothianidin were effective against wheat aphids throughout the winter wheat growing season and reduced the yield loss under field conditions. Imidacloprid and clothianidin seed treatments may be an important component of the integrated management of wheat aphids on winter wheat. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  16. Modelling seasonal effects of temperature and precipitation on honey bee winter mortality in a temperate climate.

    PubMed

    Switanek, Matthew; Crailsheim, Karl; Truhetz, Heimo; Brodschneider, Robert

    2017-02-01

    Insect pollinators are essential to global food production. For this reason, it is alarming that honey bee (Apis mellifera) populations across the world have recently seen increased rates of mortality. These changes in colony mortality are often ascribed to one or more factors including parasites, diseases, pesticides, nutrition, habitat dynamics, weather and/or climate. However, the effect of climate on colony mortality has never been demonstrated. Therefore, in this study, we focus on longer-term weather conditions and/or climate's influence on honey bee winter mortality rates across Austria. Statistical correlations between monthly climate variables and winter mortality rates were investigated. Our results indicate that warmer and drier weather conditions in the preceding year were accompanied by increased winter mortality. We subsequently built a statistical model to predict colony mortality using temperature and precipitation data as predictors. Our model reduces the mean absolute error between predicted and observed colony mortalities by 9% and is statistically significant at the 99.9% confidence level. This is the first study to show clear evidence of a link between climate variability and honey bee winter mortality. Copyright © 2016 British Geological Survey, NERC. Published by Elsevier B.V. All rights reserved.

  17. 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

  18. Ecological correlates of variable organ sizes and fat loads in the most northerly-wintering shorebirds

    USGS Publications Warehouse

    Ruthrauff, Daniel R.; Dekinga, Anne; Gill, Robert E.; Summers, R.W.; Piersma, Theunis

    2013-01-01

    Shorebirds at northern latitudes during the nonbreeding season typically carry relatively large lipid stores and exhibit an up-regulation of lean tissues associated with digestion and thermogenesis. Intraspecific variation in these tissues across sites primarily reflects differences in environmental conditions. Rock (Calidris ptilocnemis (Coues, 1873)) and Purple (Calidris maritima (Brünnich, 1764)) sandpipers are closely related species having the most northerly nonbreeding distributions among shorebirds, living at latitudes up to 61°N in Cook Inlet, Alaska, and up to 71°N in northern Norway, respectively. Cook Inlet is the coldest known site used by nonbreeding shorebirds, and the region’s mudflats annually experience extensive coverage of foraging sites by sea and shore-fast ice. Accordingly, Rock Sandpipers increase their fat stores to nearly 20% of body mass during winter. In contrast, Purple Sandpipers exploit predictably ice-free rocky intertidal foraging sites and maintain low (<6.5%) fat stores. Rock Sandpipers increase the mass of lean tissues from fall to winter, including contour feathers, stomach, and liver components. They also have greater lean pectoralis and supracoracoideus muscle and liver and kidney tissues compared with Purple Sandpipers in winter. This demonstrates a combined emphasis on digestive processes and thermogenesis, whereas Purple Sandpipers primarily augment organs associated with digestive processes. The high winter fat loads and increased lean tissues of Rock Sandpipers in Cook Inlet reflect the region’s persistent cold and abundant but sporadically unavailable food resources.

  19. Individual and colony-specific wintering areas of Pacific northern fulmars (Fulmarus glacialis)

    USGS Publications Warehouse

    Hatch, Shyla A.; Gill, V.A.; Mulcahy, D.M.

    2010-01-01

    Seabird mortality associated with longline fishing in the eastern Bering Sea occurs mainly from September to May, with northern fulmars (Fulmarus glacialis) comprising the majority (60%) of the bycatch. Along the west coast of North America, winter dieoffs of fulmars may be increasing in frequency and magnitude, the most severe on record being a wreck that peaked in October-November 2003. We deployed satellite transmitters on fulmars from the four main Alaska colonies and tracked individuals for up to 2 years. Fulmars from Hall Island (northern Bering Sea) moved to Russian coastal waters after breeding, while Pribilof Island fulmars (southeastern Bering Sea) remained relatively sedentary yearround. Birds from Chagulak Island (eastern Aleutians) preferred passes between the Aleutian Islands in winter or foraged widely over deep waters of the central Bering Sea and North Pacific. Fulmars from the Semidi Islands (western Gulf of Alaska) migrated directly to waters of the California Current. Individuals from St. George Island (Pribilofs) and Chagulak were consistent in the places that they visited in two successive winters. The Pribilof Islands population is most affected by winter longlining for groundfish, whereas the Semidi Islands colony sustains most of the natural mortality that occurs off Washington, Oregon, and California.

  20. A risk analysis of winter navigation in Finnish sea areas.

    PubMed

    Valdez Banda, Osiris A; Goerlandt, Floris; Montewka, Jakub; Kujala, Pentti

    2015-06-01

    Winter navigation is a complex but common operation in north-European sea areas. In Finnish waters, the smooth flow of maritime traffic and safety of vessel navigation during the winter period are managed through the Finnish-Swedish winter navigation system (FSWNS). This article focuses on accident risks in winter navigation operations, beginning with a brief outline of the FSWNS. The study analyses a hazard identification model of winter navigation and reviews accident data extracted from four winter periods. These are adopted as a basis for visualizing the risks in winter navigation operations. The results reveal that experts consider ship independent navigation in ice conditions the most complex navigational operation, which is confirmed by accident data analysis showing that the operation constitutes the type of navigation with the highest number of accidents reported. The severity of the accidents during winter navigation is mainly categorized as less serious. Collision is the most typical accident in ice navigation and general cargo the type of vessel most frequently involved in these accidents. Consolidated ice, ice ridges and ice thickness between 15 and 40cm represent the most common ice conditions in which accidents occur. Thus, the analysis presented in this article establishes the key elements for identifying the operation types which would benefit most from further safety engineering and safety or risk management development. Copyright © 2015 Elsevier Ltd. All rights reserved.