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1

Impact of declining Arctic sea ice on winter snowfall Jiping Liua,b,1  

E-print Network

Impact of declining Arctic sea ice on winter snowfall Jiping Liua,b,1 , Judith A. Currya , Huijun in recent dec- ades, anomalously large snowfall in recent winters has affected large parts of North America, supporting increased heavy snowfall in Europe during early winter and the northeastern and midwestern United

2

Impact of declining Arctic sea ice on winter snowfall  

PubMed Central

While the Arctic region has been warming strongly in recent decades, anomalously large snowfall in recent winters has affected large parts of North America, Europe, and east Asia. Here we demonstrate that the decrease in autumn Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation that have some resemblance to the negative phase of the winter Arctic oscillation. However, the atmospheric circulation change linked to the reduction of sea ice shows much broader meridional meanders in midlatitudes and clearly different interannual variability than the classical Arctic oscillation. This circulation change results in more frequent episodes of blocking patterns that lead to increased cold surges over large parts of northern continents. Moreover, the increase in atmospheric water vapor content in the Arctic region during late autumn and winter driven locally by the reduction of sea ice provides enhanced moisture sources, supporting increased heavy snowfall in Europe during early winter and the northeastern and midwestern United States during winter. We conclude that the recent decline of Arctic sea ice has played a critical role in recent cold and snowy winters. PMID:22371563

Liu, Jiping; Curry, Judith A.; Wang, Huijun; Song, Mirong; Horton, Radley M.

2012-01-01

3

Impact of declining Arctic sea ice on winter snowfall.  

PubMed

While the Arctic region has been warming strongly in recent decades, anomalously large snowfall in recent winters has affected large parts of North America, Europe, and east Asia. Here we demonstrate that the decrease in autumn Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation that have some resemblance to the negative phase of the winter Arctic oscillation. However, the atmospheric circulation change linked to the reduction of sea ice shows much broader meridional meanders in midlatitudes and clearly different interannual variability than the classical Arctic oscillation. This circulation change results in more frequent episodes of blocking patterns that lead to increased cold surges over large parts of northern continents. Moreover, the increase in atmospheric water vapor content in the Arctic region during late autumn and winter driven locally by the reduction of sea ice provides enhanced moisture sources, supporting increased heavy snowfall in Europe during early winter and the northeastern and midwestern United States during winter. We conclude that the recent decline of Arctic sea ice has played a critical role in recent cold and snowy winters. PMID:22371563

Liu, Jiping; Curry, Judith A; Wang, Huijun; Song, Mirong; Horton, Radley M

2012-03-13

4

Winter Snowfall Turns an Emerald White  

NASA Technical Reports Server (NTRS)

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

2001-01-01

5

Synoptic associations of winter climate and snowfall variability in New England, USA, 1950-1992  

Microsoft Academic Search

Seasonal snowfall in New England has exhibited wide variations over the last few decades, the underlying causes of which have not been identified previously. In this paper, compositing and statistical analyses examine how interactions among the large-scale atmospheric circulation, cyclonic activity and storm track preferences, and western Atlantic sea-surface temperatures contribute to winter climate variability and exceptional winter snowfall totals

Suzanne Hartley; Michael J. Keables

1998-01-01

6

3.2.3 Snowfall Accumulation Estimates The IBM for forecasting winter season precipitation does not independently provide a  

E-print Network

106 3.2.3 Snowfall Accumulation Estimates The IBM for forecasting winter season precipitation does not independently provide a prediction of snowfall accumulation. In order to make a quantitative snowfall estimate and fails to accurately predict the snowfall accumulation in many situations. Furthermore, GM was designed

Martin, Jonathan E.

7

Comparison of weather station snowfall with winter snow accumulation in high arctic basins  

Microsoft Academic Search

Most water balance studies in the High Arctic indicate that the weather stations underestimate annual precipitation, but the magnitude of such error is unknown. Based on up to seven years of field measurements, this study provides a comparison of snowfall at weather stations with the winter snow accumulation in their nearby drainage basins.Snowfall is the major form of precipitation in

Richard Heron; Peter Steer

1983-01-01

8

Some reports of snowfall from fog during the UK winter of 2008/09  

E-print Network

Snowfall during anticyclonic, non-frontal, and foggy conditions is surprising. Because it is often not forecast, it can present a hazard to transport and modify the surface albedo. In this report, we present some observations of snowfall during conditions of freezing fog in the UK during the winter of 2008/09.

Wood, Curtis R

2009-01-01

9

Increasing Great Lake-Effect Snowfall during the Twentieth Century: A Regional Response to Global Warming?.  

NASA Astrophysics Data System (ADS)

The influence of the Laurentian Great Lakes on the climate of surrounding regions is significant, especially in leeward settings where lake-effect snowfall occurs. Heavy lake-effect snow represents a potential natural hazard and plays important roles in winter recreational activities, agriculture, and regional hydrology. Changes in lake-effect snowfall may represent a regional-scale manifestation of hemispheric-scale climate change, such as that associated with global warming. This study examines records of snowfall from several lake-effect and non-lake-effect sites throughout most of the twentieth century in order to 1) determine whether differences in snowfall trends exist between these settings and 2) offer possible linkages between lake-effect snow trends and records of air temperature, water temperature, and ice cover. A new, historic record of oxygen isotope [?18O(CaCO3)] data from the sediments of three eastern Finger Lakes in central New York is presented as a means of independently assessing changes in Great Lakes lake-effect snowfall. Results reveal a statistically significant increasing trend in snowfall for the lake-effect sites, whereas no trend is observed in the non-lake-effect settings. The Finger Lake oxygen isotope record reflects this increase in lake-effect snow through a statistically significant trend toward lower ?18O(CaCO3) values. Records of air temperature, water temperature, and lake ice suggest that the observed lake-effect snow increase during the twentieth century may be the result of warmer Great Lakes surface waters and decreased ice cover, both of which are consistent with the historic upward trend in Northern Hemispheric temperature due to global warming. Given projected increases in future global temperature, areas downwind of the Great Lakes may experience increased lake-effect snowfall for the foreseeable future.

Burnett, Adam W.; Kirby, Matthew E.; Mullins, Henry T.; Patterson, William P.

2003-11-01

10

Synoptic Mechanisms Associated with Snowfall Increases to the Lee of Lakes Erie and Ontario  

NASA Astrophysics Data System (ADS)

Snowfall is a cyrospheric variable that impacts nearly every sector of society. Because of its societal importance, snowfall is a logical variable to be used as an indicator of potential global environmental change. This study investigates the mechanisms responsible for large observed snowfall increases across the eastern Great Lakes region of the USA. Results indicate that mean snowfall amounts across sections of western New York and north-western Pennsylvania have increased by up to 100 cm over the 60-year period encompassing the snowfall seasons 1930-1931 through to 1989-1990. A synoptic climatological approach is utilized to identify consistent synoptic-scale atmospheric patterns responsible for snowfall across the region. Nine synoptic types are identified as producing significan t snowfall in the study area; five with synoptic characteristics indicative of lake-effect snowfall and four evidencing characteristics of snowfall associated with cyclonic influence.An examination of the seasonal frequency of the nine synoptic types indicates a substantial increase in the frequency of the five lake-effect synoptic types and a long-term decrease in the numbers of cyclone synoptic types over the period 1950-1951 through to 1981-1982. Information concerning trends in the frequency and the intensity of each of the nine snowfall-producing synoptic types was combined to produce a modelled snowfall change due to frequency and intensity variations over the period. Trends in the frequency and intensity of the synoptic patterns associated with lake- effect snowfall explain the majority of the observed snowfall increase across the region. Variations in the synoptic types associated with cyclonically induced snowfall are shown to be unimportant to snowfall changes across the eastern Great Lakes area. Possible reasons for increases in the frequency and the intensity of the lake-effect synoptic types are discussed.

Leathers, Daniel J.; Ellis, Andrew W.

1996-10-01

11

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

12

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

PubMed

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

Tessier, Jack T

2014-05-20

13

Lunch Brie ng The winter of 2009-2010 broke snowfall accumulation and extreme cold records in cities and rural communities  

E-print Network

­ Lunch Brie ng ­ The winter of 2009-2010 broke snowfall accumulation and extreme cold records.S. is not the only nation experiencing harsh winters. Europe saw unprecedented snowfalls and record cold temperatures Geophysical Union (AGU), and the Weather Coalition. These sponsoring groups share in common a dedication

14

The Estimation of Snowfall Rate Using Visibility  

Microsoft Academic Search

The relationship between liquid equivalent snowfall rate and visibility is investigated using data collected at the National Center for Atmospheric Research Marshall Snowfall Test Site during two winter field seasons and using theoretical relationships. The observational data include simultaneous liquid equivalent snowfall rate, crystal types, and both automated and manual visibility measurements. Theoretical relationships between liquid equivalent snowfall rate and

Roy M. Rasmussen; Jothiram Vivekanandan; Jeffrey Cole; Barry Myers; Charles Masters

1999-01-01

15

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

NASA Astrophysics Data System (ADS)

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 influence of teleconnections on seasonal snowfall in CNY was not pronounced; however, there was a slight significant (5%) correlation (< 0.35) with the Atlantic Multidecadal Oscillation. It was not clear if changes in air temperature or changes in precipitation were the cause of variations in snowfall trends. It was also inconclusive if the elevation or distance from Lake Ontario resulted in increased snowfall trends. Results from this study will aid in seasonal snowfall forecasts in CNY, which can be used to predict future snowfall. Even though the study area is regionally specific, the methods may be applied to other lake effect dominated areas to determine temporal and spatial variations in snowfall. This study will enhance climatologists and operational forecasters' awareness and understanding of snowfall, especially lake effect snowfall in CNY.

Hartnett, Justin Joseph

16

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

17

STATISTICAL GUIDANCE METHODS FOR PREDICTING SNOWFALL ACCUMULATION IN THE NORTHEAST UNITED STATES.  

E-print Network

??Accurate forecasting of snowfall accumulation has widespread economic and safety consequences. Owing to the complex characteristics and dynamics inherent in winter weather systems, snowfall accumulation… (more)

McCandless, Tyler

2010-01-01

18

Role of extreme snowfall events in interannual variability of snowfall accumulation in the western United States  

NASA Astrophysics Data System (ADS)

resources in the western United States are contingent on interannual variations in snowpack. Interannual snowpack variability has been attributed to large-scale climate patterns including the El Niño-Southern Oscillation (ENSO), however, the contribution of snowfall frequency and extreme snowfall events to this variability are less well quantified. Long-term records from Snowpack Telemetry and Cooperative Observer Program stations in the 11 western states were used to investigate these relationships by considering the number of snowfall days and snowfall water equivalent (SFE) of extreme snowfall events. The top decile of snowfall events contributed 20-38% of annual SFE, depending on the region. An average of 65% and 69% of the interannual variability in annual SFE was explained by snowfall days and SFE of top decile snowfall events, respectively, with extreme events being a more significant predictor at most stations. The latitudinal dipole in SFE during ENSO phases results from changes in snowfall frequency and extreme events. In the Pacific Northwest, above normal SFE during La Niña winters was a product of both larger contributions from extremes and more snowfall days, while below normal SFE during El Niño winters was primarily associated with a substantial reduction in extremes. Conversely, annual SFE during ENSO phases in the mountains of Arizona was more closely linked to fluctuations in snowfall days than extremes. Results indicate the importance of extreme snowfall events in shaping interannual variability in water resources and suggest that improved predictive ability may inform better water resource management now and in the coming decades.

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

2014-04-01

19

The influence of snowfall, temperature and social relationships on sleeping clusters of Japanese monkeys during winter in Shiga Heights.  

PubMed

We studied Japanese monkeys (Macaca fuscata) of the Shiga A(1) troop at their sleeping sites in Shiga Heights, Japan, for 41 nights during 3 winters. Monkeys chose their sleeping sites in Japanese cedars and in deciduous broad-leaved forests on non-snowing nights and in Japanese cedar forests on snowing nights. We counted 399 sleeping clusters in which 2 or more monkeys remained in physical contact through the night and 43 solitary sleeping monkeys, though monkeys did not maintain physical contact with others in the daytime. We found 397 clusters on tree branches and 2 clusters on rocks. The mean size of huddling clusters was 3.06+/-1.22 SD. The cluster size (3.17+/-1.26 SD) at lower ambient temperatures between -7 and -4 degrees C was larger than that at higher temperatures between -2 and 4 degrees C (cluster size 2.88+/-1.13 SD). Most clusters were composed of kin. Females kept close to related females in the daytime and huddled with them at night. The highest-ranking male mainly huddled with his kin and his familiar females. Other males kept farther apart from each other in the daytime, probably to avoid social conflicts. Through cold winter nights, however, such males reduced inter-individual distances and huddled with other males. Japanese monkeys appear to recognize three types of inter-individual distances: an intimate distance less than 1 m, a personal distance of 1-3 m and a social distance of 3-20 m; they change their inter-individual distances according to social and ecological circumstances. PMID:16897193

Wada, Kazuo; Tokida, Eishi; Ogawa, Hideshi

2007-04-01

20

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)

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, such as northern Quebec. A signal-to-noise analysis reveals that the projected changes in snowfall are likely to become apparent during the twenty-first century for most locations in the Northern Hemisphere.

Krasting, John P.

21

Sensitivity of soil respiration and microbial communities to altered snowfall Zachary T. Aanderud a,1  

E-print Network

Sensitivity of soil respiration and microbial communities to altered snowfall Zachary T. Aanderud a snow-covered ecosystems Seed banks Sub-zero conditions Winter CO2 ux a b s t r a c t Winter respiration in winter soil respiration may be in uenced by the effects of snowfall on microbial communities

Fierer, Noah

22

Impacts of ENSO on Snowfall Frequencies in the United States  

Microsoft Academic Search

Changes in the frequency of occurrence of snowfall during El Nino-Southern Oscillation (ENSO) events are presented for the continental United States. This study is motivated by the need to improve winter climate forecasts for government agencies (i.e., U.S. Department of Transportation and Department of Energy) and winter entertainment facilities and the need for climatological studies. Daily snowfall data from 442

Jillien M. Patten; Shawn R. Smith

2003-01-01

23

Sunspots and Snowfall  

ERIC Educational Resources Information Center

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

Starr, Richard R.

1978-01-01

24

Increased vagal tone during winter in subsyndromal seasonal affective disorder  

Microsoft Academic Search

Background: Seasonal affective disorder (SAD) is characterized by recurrent winter depression with summer remissions and\\/or hypomania. Further symptoms include hypersomnia, increased appetite, weight gain, fatigue, and social withdrawal, which may indicate autonomic changes during winter.Methods: Measurements of respiratory sinus arrhythmia, heart rate (HR), and skin conductance level (SCL) were taken from 32 participants in subsyndromal SAD and control groups (eight

Margaret L Austen; George V Wilson

2001-01-01

25

Atlantic influence on spring snowfall over the Alps in the past 150 years  

NASA Astrophysics Data System (ADS)

Global warming is believed to be responsible for the reduction of snow amount and duration over the Alps. In fact, a rapid shortening of the snowy season has been measured and perceived by ecosystems and society in the past 30 years, despite the large year-to-year variability. This trend is projected to continue during the 21st century in the climate change scenarios with increasing greenhouse gas concentrations. Superimposed on the long-term trend, however, there is a low-frequency variability of snowfall associated with multi-decadal changes in the large-scale circulation. The amplitude of this natural low-frequency variation might be relatively large, determining rapid and substantial changes of snowfall, as recently observed. This is already known for winter snowfall over the Alps in connection with the recent tendency toward the positive phase of the North Atlantic Oscillation. In this study, we show that the low-frequency variability of Alpine spring snowfall in the past 150 years is affected by the Atlantic Multi-decadal Oscillation (AMO), which is a natural periodic fluctuation of Northern Atlantic sea surface temperature. Therefore, the recently observed spring snowfall reduction might be, at least in part, explained by the shift toward a positive AMO phase that happened in the 1990s.

Zampieri, Matteo; Scoccimarro, Enrico; Gualdi, Silvio

2013-09-01

26

Snowfall Retrivals Using a Video Disdrometer  

NASA Astrophysics Data System (ADS)

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.

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

2004-12-01

27

Quantitative Estimates of the Effect of Lake Michigan on Snowfall  

Microsoft Academic Search

A climatological study of snowfall in the snowbelts of Michigan shows that decade-average amounts varied by a factor of 2 during the period from 1909\\/10 through 1980\\/81.The effect of Lake Michigan on total winter snowfall along its shores has been estimated. A long-term average effect of +10% is found for the Wisconsin shore south of Sheboygan, and an average of

Roscoe R. Braham Jr.; Maureen J. Dungey

1984-01-01

28

Unusually cold and dry winters increase mortality in Australia.  

PubMed

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

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

2015-01-01

29

A Snowfall Impact Scale Derived from Northeast Storm Snowfall Distributions  

Microsoft Academic Search

A Northeast snowfall impact scale (NESIS) is presented to convey a measure of the impact of heavy snowfall in the Northeast urban corridor, a region that extends from southern Virginia to New England. The scale is derived from a synoptic climatology of 30 major snowstorms in the Northeast urban corridor and applied to the snowfall distribution of 70 snowstorms east

Paul J. Kocin; Louis W. Uccellini

2004-01-01

30

Radar reflectivity in snowfall  

Microsoft Academic Search

Backscattering properties of dry snowflakes at different microwave frequencies are examined. It is shown that the Rayleigh approximation does not often provide the necessary accuracy for snowflake reflectivity calculations for radar wavelengths used in meteorology; however, another simple approximation, the Rayleigh-Gans approximation, can be safely used for such calculations. Reflectivity-snowfall rate relationships are derived for different snow densities and different

S. Y. Matrosov

1992-01-01

31

A Comparison of Great Lakes Winter Severity and Ice Cover Winter 1990 vs. the Historical Record  

E-print Network

snowfall and ice formation. Winter temperature severity is evaluated in terms of magnitude and date a descriptive.ana1ysis of this winter, early tiwinter monthly air temperature and snowfall, resultsc) during the past 93 years. KLOMEEW =-0 50 la, 150 200 Figure 1. Locatior.map of snowfall stations

32

Snowfall observations from natural-draft cooling tower plumes  

Microsoft Academic Search

During the winter of 1975-1976, snowfall from the plumes of large natural-draft cooling towers of power plants has been observed. Snow accumulations up to 2.5 centimeters have been found on the ground at extended distances from the cooling towers, and visibility has been restricted to less than 1600 meters in the tower plume near ground level.

M. L. Kramer; D. E. Seymour; M. E. Smith; R. W. Reeves; T. T. Frankenberg

1976-01-01

33

Response of Rates and Sources of Ecosystem CO2 Efflux to Increasing Levels of Winter Snow Depth in the High Arctic of Northwest Greenland  

NASA Astrophysics Data System (ADS)

Arctic soils contain vast amounts of organic carbon (C) that range in age from modern to ancient. These soil C pools may be especially vulnerable to changes in conditions; especially increases in winter snowfall, as deeper snow will insulate soils in winter, and add moisture in summer. While, snowfall is increasing in many parts of the Arctic, how increases in winter precipitation affect C cycling in the High Arctic is largely unknown. In this project, we used a long-term snowpack manipulation to develop a better understanding of current and future soil C cycling under conditions of deep winter snow pack and the associated feedbacks to future atmospheric CO2 levels. We examined the effects of three levels of winter snowpack (ambient (0.25 m), ×2, ×4) on the timing, magnitude and sources of ecosystem CO2 efflux and soil microclimate in prostrate dwarf-shrub tundra on patterned ground in the High Arctic of NW Greenland. From June to August 2010 and 2011 we monitored ecosystem CO2 efflux and soil CO2 concentrations (LI-COR 800 & 840) together with soil temperature and moisture daily and the radiocarbon (14C) content of CO2 monthly. The 14C content of CO2 can be used to infer the dominant source of CO2 (plant vs. microbially-respired) as well as the age of microbially-respired CO2. Initial results indicate that during the 2010 sampling period (Jun 28 - Aug 16), daily CO2 emissions from vegetated areas were higher under ×4 ambient snowpack relative to ambient snowpack (84.9 vs. 53.1 mmol m-2 d-1), but lower under ×2 ambient snowpack (56.7 mmol m-2 d-1). CO2 emissions from bare areas increased with snowpack depth from ambient (8.6 mmol m-2 d-1) to ×2 ambient snowpack (16.5 mmol m-2 d-1) to x4 ambient snowpack (18.9 mmol m-2 d-1). Midsummer ecosystem CO2 emissions were dominated by modern C; additional 14C measurements are in progress. Our findings indicate that increases in snowpack may stimulate C loss from this high arctic ecosystem - probably facilitated by higher soil moisture - providing positive feedback to rising atmospheric CO2 levels.

Thomas, J. S.; Lupascu, M.; Xu, X.; Maseyk, K. S.; Welker, J. M.; Czimczik, C. I.

2011-12-01

34

Artificial lighting during winter increases milk yield in dairy ewes.  

PubMed

In Australia, the supply of sheep milk is reduced during the winter. Housing dairy animals under lights during winter is a simple technique to increase milk yield; however, it is difficult to predict the magnitude of this increase in dairy ewes, because there are few corroborating data. We studied 220 East Friesian crossbred ewes (50 primiparous and 170 multiparous ewes, respectively) that lambed in April to May 2007 (late autumn, southern hemisphere) and were weaned from their lambs within 24 h of parturition and milked exclusively by machine. These ewes were ranked according to their milk production, and ewes producing > or =1,000 mL/d of milk were allocated to 1 of 2 groups. One group of ewes was kept indoors under a long-day photoperiod (16 h of light), whereas the other group was kept indoors under a naturally declining day length. Ewes were maintained under these conditions for 8 wk. Milk yield was measured twice weekly, and ewe weight and condition were measured at weekly intervals. From a subset of ewes (n = 20 per group), milk samples were collected twice weekly at the morning milking to measure milk lipid, protein, and lactose, and blood samples were collected once a week to measure plasma prolactin concentrations. Mean daily milk yield was analyzed as a percentage of preexperimental milk yield because the milk yield of ewes housed under the long photoperiod was lower than that of ewes under a declining day length when the treatments began. Thus, the ewes under a long photoperiod yielded 91.7% of their starting yield by wk 8 of treatment, whereas ewes under a declining day length yielded 76.25% of their initial value (LSD = 5.1), and this divergence in milk yield was apparent by wk 2 of treatment. Mean plasma prolactin levels were greater in ewes housed under the long-day photoperiod (n = 20) compared with control ewes (n = 20) at wk 6 (168 +/- 27 vs. 72 +/- 19 ng/mL, respectively), wk 7 (125 +/- 28 vs. 37 +/- 7 ng/mL, respectively), and wk 8 of the experiment (132 +/- 35 vs. 31 +/- 7 ng/mL, respectively). The composition of the milk was similar between the groups at each time point, and milk from these ewes (n = 20 per group) contained, on average, 6.1 +/- 0.05% lipid, 4.8 +/- 0.02% protein, and 5.4 +/- 0.01% lactose (n = 309 samples). We concluded that ewes increase milk production in response to being housed under a long-day photoperiod during winter. PMID:18946128

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

2008-11-01

35

Winter methane dynamics in a temperate peatland  

NASA Astrophysics Data System (ADS)

Methane (CH4) dynamics in pore water, snow pore air, and surface emissions were investigated in a temperate poor fen in New Hampshire over several winters. Total snowfall and average air temperatures during winter months (defined as December, January, and February) were climatologic indicators of significant flux rates from this midlatitude poor fen. Average winter emissions, for the five winters ending in 1994-1995, were 20, 39, 53, 56, and 26 mg m-2 d-1, amounting to 2.0, 5.2, 6.6, 9.2, and 2.0% of the total annual fluxes, respectively. Totaling emissions over 5 years that represent low to average snowfall, winter accounted for 4.3% of emissions to the atmosphere. Winter flux rates were near 55 mg m-2 d-1 for years with average snowfall, and 25 mg m-2 d-1 for years with low snowfall. Concentrations of CH4 sampled in pore water immediately beneath the ice were highly variable (0 to 1.1 mM). The concentration magnitude and standard deviation increased toward the fen center and correlated with spatial variation in hydrology, peat texture, and peat depth. CH4 stores increased in the near-surface pore water as the ice cover formed. Seasonal CH4 buildup in deeper peat began near the end of the growing season, probably due to changing transport mechanisms and temperature effects on solubility. Stored CH4 in the 25- to 75-cm peat layer decreased by 2.7 g m-2 between January and June 1995.

Melloh, Rae A.; Crill, Patrick M.

1996-06-01

36

Measuring Snowfall with Solar Panels  

USGS Multimedia Gallery

Using the device pictured here, government scientists are measuring snowfall in remote areas with a bucket, a small windmill, and the sun -- all the while saving money, energy, and ultimately helping to save lives. ...

37

Trends in snowfall versus rainfall in the western United States  

USGS Publications Warehouse

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.

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

2006-01-01

38

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

NASA Astrophysics Data System (ADS)

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

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

1993-10-01

39

A Snowfall Impact Scale Derived from Northeast Storm Snowfall Distributions.  

NASA Astrophysics Data System (ADS)

A Northeast snowfall impact scale (NESIS) is presented to convey a measure of the impact of heavy snowfall in the Northeast urban corridor, a region that extends from southern Virginia to New England. The scale is derived from a synoptic climatology of 30 major snowstorms in the Northeast urban corridor and applied to the snowfall distribution of 70 snowstorms east of the Rocky Mountains. NESIS is similar in concept to other meteorological scales that are designed to simplify complex phenomena into an easily understood range of values. The Fujita scale for tornadoes and the Saffir Simpson scale for hurricanes measure the potential for destruction to property and loss of life by wind-related damage (and storm surge for Saffir Simpson) through use of a categorical ranking (0 or 1 5).

Kocin, Paul J.; Uccellini, Louis W.

2004-02-01

40

An evaluation of the Wyoming gauge system for snowfall measurement  

USGS Publications Warehouse

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.

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

2000-01-01

41

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

NASA Astrophysics Data System (ADS)

The North Atlantic Oscillation (NAO) is one of the main components of atmospheric circulation variability within the middle and high latitudes of the Northern Hemisphere, particularly impacting winter weather patterns in northeastern United States. Previous research has indicated greater snowfall totals and higher frequency of snowfall days in the Northeast during a NAO negative phase due to repeated polar outbreaks; yet, the NAO positive phase has also been associated with extreme snowfall events in this region. This study examines the relationship between the NAO and winter (December - February) snowfall totals in northeastern U.S. between 1961 and 2010. Two case studies of recent winter events with differing NAO phases were evaluated to provide insight on how both NAO phases can produce significant snowfall in portions of the Northeast. The analysis revealed an inverse relationship between the NAO phase and seasonal snowfall, with positive (negative) NAO index years associated with lower (higher) average snowfall and snowfall days. Significantly greater snowfall during the NAO negative phase was mainly located along the East Coast as well as the interior southern half of the study region. A composite analysis of various tropospheric variables (e.g., 500-hPa heights) showed NAO negative years produced greater snowfall due to more extreme weather conditions affecting the Northeast, such as below normal sea level pressure, a deepened mid-tropospheric trough and weaker upper-level westerlies that permitted more frequent polar outbreaks. The intrusion of cold polar air into the interior U.S. generates more extreme temperature gradients and produces snowfall farther south than the NAO positive phase. In addition, the eastward displacement of the storms in the NAO negative phase along with the available moisture from the Atlantic Ocean creates more snowfall along the East Coast. These results correspond to the spatial distribution of snowfall that occurred during the February 2010 winter storms that produced significant snowfall throughout most of the Northeast, particularly around the mid-Atlantic. On the other hand, stations indicating no relationship between NAO and snowfall were mainly located in western and central New York, northern Vermont, and Maine. These regions of the Northeast correspond to those that receive snowfall in either NAO phase, as exhibited in the case studies, due to the effects of nearby lakes and higher terrain related to the storm tracks through these areas. Winter storms track over this northern region (of the Northeast) regardless of NAO phase whereas snowfall in the mid-Atlantic states is more dependent on a strong southerly track (i.e. Cape Hatteras/Nor'easter low) associated with the NAO negative phase. Since western New York and northwestern Pennsylvania border Lake Ontario and Lake Erie, the stations in these regions commonly receive lake-effect snow as a result of great fetch due to the west-east orientation of both lakes. Stations in central and northern New York receive lake-effect snow as additional lift is generated when the moist air reaches the Allegheny Plateau and the Adirondack Mountains.

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

2013-12-01

42

A Climatology of Mean Monthly Snowfall for the Conterminous United States: Temporal and Spatial Patterns.  

NASA Astrophysics Data System (ADS)

Mean monthly snowfall data for 216 stations across the conterminous United States were analyzed to produce a climatology that identifies statistical, spatial and intraseasonal aspects. Geographic variations in the length of the snowfall season are characterized using two statistics: the number of months of snow and the Snow Concentration Index (SCI).The annual distribution of mean monthly snowfall is also examined using harmonic analysis. Snowfall across the conterminous United States generally peaks in February; earlier snowfall maxima are found in the Great Lakes area and in the Pacific Northwest, whereas late February or March maxima occur in the western High Plains. Stations with relatively high amounts of variance explained by the second harmonic indicate 1) areas with a short snowfall season such as the southeastern United States, or 2) areas with a long snowfall season that have a tendency toward a bimodal distribution.A climatology of the changing monthly patterns of snowfall is identified through the mapping of station deviations from a national composite. This procedure produces contiguous regions that can be related to seasonal changes in the extent and positioning of the circumpolar vortex. The maps reveal that positive snowfall deviations predominate 1) in autumn in the northern and western Great Plains and the Rocky Mountains (with a full-latitude trough over the central United States and associated upslope precipitation); 2) in early winter in the Great Lakes (associated with lake-effect storms); 3) in late winter over the southern and western states (with a fully expanded circumpolar vortex); and 4) in spring in the western states (linked to seasonal changes in preferred locations of cyclogenesis and associated storm tracks).

Harrington, John A., Jr.; Cerveny, Randall S.; Dewey, Kenneth F.

1987-08-01

43

EXPERIENCES SHOWING HOW INCREASED WINTER FLOW THROUGH INLAND LAKES INFLUENCES ICE CONDITIONS  

Microsoft Academic Search

In Norway, most water power projects cause increased winter flow in the rivers and through the lakes. This paper deals with some aspects of the changes in temperature distribution in, and ice conditions on the lakes, when subject to increased winter flow. The main factors which affect ice conditions in lakes, are the temperature and rate of the inflowing water.

RANDI PYTTE ASVALL; SYVER ROEN

1974-01-01

44

Improving Radar Snowfall Measurements Using a Video Disdrometer  

NASA Astrophysics Data System (ADS)

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.

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

2005-05-01

45

Flaking Out: Snowfall, Disruptions of Instructional Time,  

E-print Network

Flaking Out: Snowfall, Disruptions of Instructional Time, and Student Achievement Joshua Goodman is correlated with within-student variation in performance by subject (Lavy, 2010). · Snowfall in Maryland to student achievement. · I'll use variation in snowfall across time and space as an exogenous source

Liu, X. Shirley

46

4, 515534, 2008 Snowfall response to  

E-print Network

CPD 4, 515­534, 2008 Snowfall response to obliquity forcing S.-Y. Lee and C. J. Poulsen Title Page­534, 2008 Snowfall response to obliquity forcing S.-Y. Lee and C. J. Poulsen Title Page Abstract circulation model to quantify changes in continental snowfall associated with mean-annual and seasonal

Paris-Sud XI, Université de

47

Snowfall, snowpack, and meltwater chemistry  

Technology Transfer Automated Retrieval System (TEKTRAN)

Biogeochemical cycling of nutrients and pollutants in the environment is significantly affected by the occurrence of snowfall and snowpacks. Snowpacks can be viewed as reservoirs of chemicals that, unlike substances dissolved in rainfall, can be largely stored for significant periods of time during...

48

Extreme snowfall events in the western United States: Variability, change, and implications for water resource management  

NASA Astrophysics Data System (ADS)

In the western United States, seasonal snow accumulation largely determines water resource availability. Natural climate variability and anthropogenic climate change present challenges to water managers who must distribute a highly allocated water supply to satisfy many competing objectives. Extreme snowfall events are found to contribute 20-38% of annual snowfall water equivalent (SFE) and shape nearly 70% of interannual variability in annual SFE on average. By midcentury, increasing temperatures are projected to decrease the size of extreme snowfall events and the portion of annual SFE contributed by these events. Projected increases in the interannual variability of extreme snowfall events are expected to enhance interannual variability in annual SFE, resulting in less and more variable snowfall in the future. We present a SFE analysis tool that utilizes the strong relationships between annual SFE and extreme events to provide probabilistic guidance for seasonal SFE forecasts.

Lute, Abigail C.

49

Modeling Backscatter Properties of Snowfall at Millimeter Wavelengths  

Microsoft Academic Search

ABSTRACT Ground-based,vertically pointing and airborne\\/spaceborne nadir-pointing millimeter-wavelength radars are being increasingly used worldwide. Though such radars are primarily designed for cloud remote sensing, they can also be used for precipitation measurements including snowfall estimates. In this study, modeling of snowfall radar properties is performed,for the common,frequencies of millimeter-wavelength radars such as those used by the U.S. Department,of Energy’s Atmospheric,Radiation Measurement,Program

Sergey Y. Matrosov

2007-01-01

50

Ecosystem CO2 production during winter in a Swedish subarctic region: the relative importance of climate and vegetation type  

Microsoft Academic Search

General circulation models consistently predict that regional warming will be most rapid in the Arctic, that this warming will be predominantly in the winter season, and that it will often be accompanied by increasing snowfall. Paradoxically, despite the strong cold season emphasis in these predictions, we know relatively little about the plot and landscape-level controls on tundra biogeochemical cycling in

PAUL G ROGAN; S VEN J ONASSON

2006-01-01

51

When Elk are Excluded, Aspen Growth Dramatically Increases  

USGS Multimedia Gallery

Climate change in the form of reduced snowfall in mountains  is causing powerful and cascading shifts in montane plant and bird communities through the increased ability of elk to stay at high elevations over winter and consume plants. Here, you can see an example of the difference in aspe...

52

A nested modeling study of elevation-dependent climate change signals in California induced by increased atmospheric CO2  

SciTech Connect

Dynamically downscaled climate change signals due to increased atmospheric CO2 are investigated for three California basins. The downscaled signals show strong elevation dependence, mainly due to elevated freezing levels in the increased CO2 climate. Below 2.5 km, rainfall increases by over 150% while snowfall decreases by 20-40% in the winter. Above 2.5 km, rainfall and snowfall both increase in the winter, as the freezing levels appear mostly below this level. Winter snowmelt increases in all elevations due to warmer temperatures in the increased CO2 climate. Reduced snowfall and enhanced snowmelt during the winter decreases snowmelt-driven spring runoff below the 2.5 km level, where the peak snowmelt occurs one month earlier in the increased CO2 climate. Above 2.5km, increased winter snowfall maintains snowmelt-driven runoff through most of the warm season. The altered hydrologic characteristics in the increased CO2 climate affect the diurnal temperature variation mainly via snow-albedo-soil moisture feedback.

Kim, Jinwon

2001-06-04

53

REGIONAL SNOWFALL PATTERNS IN THE HIGH, ARID ANDES MATHIAS VUILLE and CASPAR AMMANN  

E-print Network

/AVHRR satellite data. The results show that snowfall during winter (May­September) is a quite regular phenomenon zones in the past would have left tracks in different paleoarchives (paleosols, moraines, lacustrine, areas above 4000 m in dark gray, Pacific ocean, lakes and salars (salt pans) in black). [182] #12

Massachusetts at Amherst, University of

54

An indoor public space for a winter city  

E-print Network

Winter is a marginalized season in North American design. Even though most cities in the northern United States and Canada have winter conditions-snowfall, ice, freezing temperatures, and long nights-for substantial portions ...

Crane, Justin Fuller

2005-01-01

55

Production System Techniques to Increase Nitrogen Use Efficiency in Winter Wheat  

Microsoft Academic Search

Most current research on winter wheat (Triticum aestivum L.) focuses on increasing yields of either grain or plant biomass. Increased production costs and environmental awareness will promote the development of methods to increase the efficiency of applied nutrients. Nitrogen (N) is often the most limiting nutrient for cereal grain production and represents one of the highest input costs in agricultural

W. E. Thomason; W. R. Raun; G. V. Johnson; K. W. Freeman; K. J. Wynn; R. W. Mullen

2002-01-01

56

Synoptic Weather Patterns Leading to Snowfall in the Northeastern United States and the Resulting Spatial Distribution of Snowfall Amounts  

NASA Astrophysics Data System (ADS)

Frozen precipitation results in hazardous conditions in the densely populated northeastern United States, yet little attention has been given to the important relationship between synoptic weather patterns and snowfall amounts. Recent increases in total seasonal snowfall amounts in some parts of the region have been attributed to increases in the frequency and/or intensity of certain weather patterns. Direct accounts of synoptic weather patterns are rarely recorded in conjunction with standard meteorological observations, and, as such, they must be diagnosed after the fact. Given the difficulty in isolating consistent synoptic weather patterns from standard meteorological datasets, to date there has been no quantitative study on the amount of snow that falls from each of the distinct synoptic systems that affect the region (nor' easters, lake-effect storms, overrunning events, etc.). This study isolates distinct synoptic types using four-times daily synoptic weather data, principal components analysis and clustering analysis for several cities in the region stretching from Maine to southwestern Virginia. The results of this synoptic typing are specific to the city for which the analysis was performed, and are not necessarily directly comparable to neighboring cities. The algorithm used to delineate synoptic types does, however, take into consideration the temporal progression of synoptic weather patterns over each city and isolates days that are transitional from one synoptic pattern to another. The calendar of daily synoptic types generated in this study is joined to a relatively high resolution, gridded snowfall dataset to isolate areas where a given synoptic pattern is responsible for a given percentage of snowfall. The final product is a series of monthly and seasonal maps of snowfall distributions resulting from each of the individual synoptic patterns.

Karmosky, C. C.

2006-05-01

57

Microwave signatures of snowfall using a combined modeling and multi-instrument observational approach  

NASA Astrophysics Data System (ADS)

Microwave snowfall retrievals have received increased attention in recent years due to the upcoming launch of the joint NASA/JAXA Global Precipitation Measurement (GPM) mission. GPM's core satellite will feature a dual-frequency Ku/Ka-band radar and multi-frequency passive microwave radiometer that will provide the first combined active/passive microwave observations of snowfall at higher latitudes. This study initially explores a GPM proxy observational dataset comprised of coincident CloudSat, AMSR-E, and higher frequency MHS microwave observations associated with frozen precipitation to illustrate the microwave scattering signature of different snowfall events. Multi-frequency microwave signatures of deeper, synoptic snowfall events will be compared to shallow, convective lake-effect snow events to illustrate the complexity of using scattering signatures for snowfall retrievals. Additionally, recent modeling work has highlighted potentially unique triple-frequency radar signatures of snowfall using non-spherical aggregate snowflake models. These modeling results will constrain the snowflake scattering properties, while the observational dataset will be used to assess multi-frequency microwave simulations using aggregate snowflake models. Particular attention will be focused on snowfall events with low columnar cloud liquid water contents to better isolate the scattering effects of frozen hydrometeors.

Kulie, M.; Hiley, M.; Bennartz, R.

2011-12-01

58

Toward estimating snowfall from space: Microphysical constraints from intensive in situ surface observations  

NASA Astrophysics Data System (ADS)

Representations of microphysical properties are necessary to the development of remote sensing algorithms for space-based observations of snowfall: to create radiative scattering and fallspeed models, to act as explicit a priori constraints, or to validate remote sensing results, for example. These representations, capturing properties such as mass, area, and shape that affect both microwave scattering and snowfall rate, would, ideally, be physically consistent and provide information about the uncertainties and environmental variability of these properties. Toward that end, a microphysical properties retrieval was developed for application to intensive, surface-based in situ observations of snowfall. The optimal estimation retrieval utilizes nearly-colocated observations of radar reflectivity, snowfall rate, size distribution and fallspeed, and produces estimates of the microphysical state. The state is represented by power law expressions giving particle mass and horizontally projected area as functions of particle size. The retrieval has been applied to four snowfall events from NH winter 2006-2007 which were observed during the Canadian CloudSat/CALIPSO Validation Project. The events consisted of both lake effect and synoptic snowfall. The retrieval was operated at moderately high time resolution in an attempt to capture the temporal variations in the microphysical properties. A rigorous assessment of measurement and forward model uncertainties was performed, and these uncertainties propagate into the retrieved states via the optimal estimation algorithm. Although significant uncertainties remain in the retrieved states, some microphysical differences between events are discernible. The retrievals additionally provide information about the multidimensional probability distribution of the state variables. Such information will likely be useful for constraining and for evaluating the uncertainty characteristics of space-based remote sensing algorithms for snowfall.

Wood, N. B.; L'Ecuyer, T. S.; Heymsfield, A.; Stephens, G. L.

2010-12-01

59

Improving Snowfall Forecasting by Diagnosing Snow Density  

Microsoft Academic Search

Current prediction of snowfall amounts is accomplished either by using empirical techniques or by using a standard modification of liquid equivalent precipitation such as the 10-to-1 rule. This rule, which supposes that the depth of the snowfall is 10 times the liquid equivalent (a snow ratio of 10:1, reflecting an assumed snow density of 100 kg m23), is a particularly

Paul J. Roebber; Sara L. Bruening; David M. Schultz; John V. Cortinas

2003-01-01

60

Experimental Studies on Amount of Snowfall by Crystal Growth in an Artificial Snowfall Device  

NASA Astrophysics Data System (ADS)

A series of experiments was conducted to estimate the amount of snowfall of dendrite-type crystals produced by an artificial snowfall device that uses the rotary ventilation mesh filter method. An expression is proposed in this paper for the amount of the snowfall. The amount of snowfall (Gs) can be expressed as Gs = ?s Vai ?W , where ?W is effective water content in the crystal growth, Vai is air mass flow and ?s is snowfall efficiency. The effective water content in the crystal growth (?W) is defined as the difference between the specific cloud water content and ice saturation vapor density. The rotary ventilation mesh filter method used in this work had a snowfall efficiency of about 90%. Even for a large amount of cloud water content, we observed only a very few super-cooled cloud droplets on snow crystals. Therefore, we can deduce that the cloud water content should contribute to crystal growth directly. We report here measurements of snowfall as a function of several input parameters and verify the validity of the proposed relationship.

Seki, Mitsuo; Umezawa, Kouichi; Abe, Osamu

61

Long-term changes in annual maximum snow depth and snowfall in Switzerland based on extreme value statistics  

Microsoft Academic Search

Mountain snow cover is an important source of water and essential for winter tourism in Alpine countries. However, large amounts\\u000a of snow can lead to destructive avalanches, floods, traffic interruptions or even the collapse of buildings. We use annual\\u000a maximum snow depth and snowfall data from 25 stations (between 200 and 2,500 m) collected during the last 80 winters (1930\\/31\\u000a to

Christoph Marty; Juliette Blanchet

2012-01-01

62

Variability and trends of total precipitation and snowfall over the United States and Canada  

SciTech Connect

The biases and large-scale inhomogeneities in the time series of measured precipitation and snowfall over the United States and Canada are discussed and analyzed. The spatial statistical characteristics of monthly and annual snowfall and total precipitation are investigated and parameterized. After adjustments and selection of the best' network, reliable first guess' estimates of North American snowfall and precipitation are obtained. Century-long time series of unbiased annual precipitation over the regions to the south of 55[degrees]N and 40-year time series of unbiased area-averaged annual precipitation and snowfall for all of North America are developed. The analysis of their trends shows the following. (1) During the last 100 years, annual precipitation has increased in southern Canada (south of 55[degrees]N) by 13% and in the contiguous United States by 4%; however, the main domain of this century-scale precipitation increase is eastern Canada and adjacent to it northern regions of the United States. (2) Up to a 20% increase has occurred in annual snowfall and rainfall during the last four decades in Canada north of 55[degrees]N. The relationships between century-long precipitation time series over North America with Northern Hemisphere surface air temperature and the South Oscillation index (SOI) are investigated. It is shown that ENSO (negative anomaly of SOI) is usually accompanied by an increase of precipitation whenever it affects the United States (especially in the southwestern region of the country).

Groisman, P.Y. (State Hydrological Institute, St. Petersburg (Russian Federation)); Easterling, D.R. (Global Climate Laboratory, Asheville, NC (United States))

1994-01-01

63

Sensitivity of Lake-Enhanced Snowfall to Lake Ice Cover in the Great Lakes Region  

NASA Astrophysics Data System (ADS)

The Great Lakes exert a significant influence on the regional climate of northern United States and southern Canada, including enhancement of cold-season precipitation on and downwind of the leeward shores. Lake-enhanced snowfall occurs when air that is significantly colder than the lake's surface temperature travels over the lake. Enhanced surface sensible and latent heat fluxes relative to the surrounding land surface result in moistening and destabilization of the atmosphere and subsequent development of low-level convection. In the Great Lakes region, lake-enhanced snow occurs during late fall through early winter, with decreasing numbers of events in the late winter due to the formation of widespread lake ice. Lake ice reduces both sensible and latent heat fluxes from the surface, thereby increasing atmospheric stability and reducing lake induced convection. The degree to which ice coverage may change in future climate scenarios is largely unknown, but it is clear that any change to the fraction and duration of lake ice coverage will have an effect on lake-atmosphere interaction and the development and intensity of lake-enhanced precipitation. This study uses the NCAR Weather, Research, and Forecasting (WRF) model to examine how changes in Great Lakes fractional ice coverage affect the presence, intensity, and quantity of lake-enhanced precipitation. Sensitivity studies are used to evaluate the evolution and change in intensity of lake-enhanced snowfall in the Great Lakes region for scenarios that include (1) lake ice cover obtained from analysis fields (control simulation), (2) ice-free lakes, and (3) 100% ice coverage. Distinct lake-effect snow bands were observed in both the control and ice-free simulations, with placement of these bands further to the south and propagating further inland in the ice-free case. Melted precipitation totals increased on the order of 10 mm for ice-free lakes along the southern edges of Lake Superior, Lake Erie, and the eastern coast of Lake Ontario, while complete ice coverage extinguished nearly all lake-effect snow bands.

Wright, D. M.; Posselt, D. J.; Steiner, A. L.

2011-12-01

64

Snowfall: Hardware Stream Analysis Made Easy Jens Teubner Louis Woods  

E-print Network

Snowfall: Hardware Stream Analysis Made Easy Jens Teubner Louis Woods ETH Zurich, Systems Group agile hardware generation for changing application demands. In this demonstration, we showcase Snowfall.g., lex/flex), Snowfall can be used to decode incoming data streams in hardware, react to low

Teubner, Jens

65

Digital Investigation of Great Lakes Regional Snowfall, 1951-1980  

E-print Network

/,, ABSTRACT Digital Investigation of Great Lakes Regional Snowfall, 1951-1980 D.C. NORTON u Laboratory 2205 Commonwealth Boulevard Ann Arbor, Michigan 48105-1593, U.S.A. A snowfall database season grids of 198,000 cells for the 1951 - 1980 period. Using these grids, multiple seasonal snowfalls

66

Insignificant Change in Antarctic Snowfall Since the International Geophysical Year  

Microsoft Academic Search

Antarctic snowfall exhibits substantial variability over a range of time scales, with consequent impacts on global sea level and the mass balance of the ice sheets. To assess how snowfall has affected the thickness of the ice sheets in Antarctica and to provide an extended perspective, we derived a 50-year time series of snowfall accumulation over the continent by combining

Andrew J. Monaghan; David H. Bromwich; Ryan L. Fogt; Sheng-Hung Wang; Paul A. Mayewski; Daniel A. Dixon; Alexey Ekaykin; Massimo Frezzotti; Ian Goodwin; Elisabeth Isaksson; Susan D. Kaspari; Vin I. Morgan; Hans Oerter; Tas D. Van Ommen; Cornelius J. Van der Veen; Jiahong Wen

2006-01-01

67

A Record Ohio Snowfall during 9-14 November 1996.  

NASA Astrophysics Data System (ADS)

A 6-day lake effect snow event produced a reported 68.9 in. (175.0 cm) of snowfall in Hambden Township, Geauga County, Ohio, during 9-14 November 1996. This exceeded the previous Ohio single-storm snowfall record of 42 in. The purpose of this research is to describe the meteorological situation that caused the record snowfall, document the site of the record snow and the methods of the measurement, describe the societal impacts of the storm, and assess the validity of the record. A persistent deep trough in the midtroposphere provided cold advection across Lake Erie into northeast Ohio. This combined with a very unstable lower atmosphere to allow deep, moist convection and a prolonged period of heavy snowfall. The observer and site were selected in 1994 for a federal study of lake effect snowfalls and the observer was a snow spotter for the National Weather Service office in Cleveland in November 1996. A review of snowfall data from the event indicates the reported snowfall is consistent with respect to snow depths, nearby reported snowfall, the synoptic situation, and societal impacts of the snow. The authors suggest the 68.9 in. of snowfall should be accepted as a new state record single-storm snowfall. In addition, the 76.7 in. (195 cm) of snowfall recorded at this site in November 1996 is a new monthly snowfall record for Ohio.

Schmidlin, Thomas W.; Kosarik, James

1999-06-01

68

Database of snowfall for analyzing vertical structure of cloud  

Microsoft Academic Search

This paper introduces a system based on a relational database containing data from a wide range of different instruments for analyzing precipitation and vertical cloud structure during snowfall. Temporal resolution of less than one minute allows distinguishing between different phases of a snowfall event. We have designed a database for snowfall measurement and populated it with data from one large

A. Teras; K. Muramoto; H. Aoyama; M. Tamura; T. Koike; H. Fujii; T. Pfaff

2003-01-01

69

Lake-Effect Snowfall over Lake Michigan.  

NASA Astrophysics Data System (ADS)

Aircraft measurements of snow particle size spectra from 36 flights on 26 snowy days are used to estimate snow precipitation rates over Lake Michigan. Results show that average rates during 14 wind-parallel-type lake-effect storms increased from the upwind shore to about midlake and then were essentially uniform (1.5 2 mm day1, liquid water equivalent) to the downwind shore. Snow from midlake bands and shoreline bands maximized over the lake. The position of the maximum during these types of lake-effect storms depends on meteorological conditions. In any given case it may be near either shore or anywhere between them. This study combines 12 cases of midlake and shoreline bands. The resulting cross-lake snow profile shows a broad maximum reaching over 4 mm day1 near midlake. The single sample maximum snow precipitation rate encountered in this study was 77.7 mm day1. The average cross-lake profile from combining 26 cases of lake-effect storms shows that snowfall into the lake is considerably greater than one would expect from a linear interpolation between values measured along either shore.An attempt is made to estimate the average increase in snow over lake Michigan resulting from combined lake-effect and large-scale cyclonic storms. The result is interesting but not considered very reliable because it depends upon the relative frequencies of different types of lake-effect storms as well as overtake snow rates from large-scale cyclonic storms; neither is well known.

Braham, Roscoe R., Jr.; Dungey, Maureen J.

1995-05-01

70

Detecting snowfall over land by satellite high-frequency microwave observations: The lack of scattering signature and a statistical approach  

NASA Astrophysics Data System (ADS)

has been long believed that the dominant microwave signature of snowfall over land is the brightness temperature decrease caused by ice scattering. However, our analysis of multiyear satellite data revealed that on most of occasions, brightness temperatures are rather higher under snowfall than nonsnowfall conditions, likely due to the emission by cloud liquid water. This brightness temperature increase masks the scattering signature and complicates the snowfall detection problem. In this study, we propose a statistical method for snowfall detection, which is developed by using CloudSat radar to train high-frequency passive microwave observations. To capture the major variations of the brightness temperatures and reduce the dimensionality of independent variables, the detection algorithm is designed to use the information contained in the first three principal components resulted from Empirical Orthogonal Function (EOF) analysis, which capture ~99% of the total variances of brightness temperatures. Given a multichannel microwave observation, the algorithm first transforms the brightness temperature vector into EOF space and then retrieves a probability of snowfall by using the CloudSat radar-trained look-up table. Validation has been carried out by case studies and averaged horizontal snowfall fraction maps. The result indicated that the algorithm has clear skills in identifying snowfall areas even over mountainous regions.

Liu, Guosheng; Seo, Eun-Kyoung

2013-02-01

71

Real-Time Snowfall Noise Elimination  

Microsoft Academic Search

We propose a new method that removes snowfall noise from successive images recorded by a TV camera. This method utilizes the size and velocity of a moving object. The intensity of a pixel changes when an object passes over the pixel. Snow particles pass a pixel very quickly due to their small size. Therefore, after holding the odd number of

Hiroyuki Hase; Kazunaga Miyake; Masaaki Yoneda

1999-01-01

72

Effects of Snowfall on Drifting Snow and Wind Structure Near a Surface  

NASA Astrophysics Data System (ADS)

Wind-tunnel and numerical experiments were performed to investigate the effects of snowfall on the wind profile and the development of drifting snow. Wind profiles and mass-flux profiles of drifting snow were measured with and without artificial snowfall over a snow surface within the tunnel. Wind and shear-stress profiles and the impact speeds of the snowflakes during snowfall were also investigated numerically. During snowfall, snowflakes transfer part of their horizontal momentum to the air, which increases the stress close to the snow surface; however, the resultant modifications of the wind profiles are small. Because snowflakes have large momentum, the decomposed snow crystals that result from their collision with a surface can form a saltation layer, even over a hard snow surface where entrainment of the grains from the surface does not occur. Additionally, during snowfall, the threshold friction velocity can be lower than the impact threshold because snowflake fragmentation facilitates snow drifting. The broken crystals contribute to the increase in the number of drifting snow grains, even below the impact threshold.

Nemoto, Masaki; Sato, Takeshi; Kosugi, Kenji; Mochizuki, Shigeto

2014-09-01

73

Tuned perfect prognostication forecasts of mesoscale snowfall for southern Ontario  

NASA Astrophysics Data System (ADS)

A procedure for producing site-specific 1- and 2-day categorical forecasts of 24-hour accumulated snowfall by statistical forecast methods has been developed and tested for a small area of Ontario adjacent to southern Georgian Bay. A perfect prognosis ("perfect prog," or PP) method was used, with predictors designed to handle lake-effect and nonlake-effect snowfall. Predictors were selected from a basic set of potential predictors by a stepwise multiple discriminant analysis (MDA) procedure done in three stages, where the third stage involved adding functions of predictors already selected in the first two stages to the basic predictor set. The third stage appears to enhance the discriminating power of the original predictor set because the number of "hits" of snowfall forecasts made with independent data was significantly increased and the distribution of forecasts was brought closer to the observed distribution. A two-step, rule-based tuning procedure was applied to the PP-MDA forecasts to help compensate for errors that arise when the PP-MDA statistical equations are used with numerical weather prediction model data, and for errors that arise from the conservative nature of MDA forecasts. A rule-based nonparametric statistical classification procedure (CART) was used in the first step. When the rules for tuning forecasts were tested with independent data, CART was found to increase the skill of the tuned forecasts, particularly in the common categories (1,2), and to improve the reliability of category 1 forecasts at a majority of the stations. However, CART was unable to find rules for infrequent and rare snow categories. Step B of the tuning procedure, a semicomputerized manual search for additional rules not seen by CART, was undertaken in an attempt to "do something" about this problem. When tested with independent data, overall improvement was found in the skill of forecasts tuned by two-step procedure, but it was too small to make an appreciable difference. Several suggestions are made in regard to exploring methods that should result in significantly improved skill of snowfall forecasts for southern Ontario by statistical forecast methods.

Burrows, William R.

1990-02-01

74

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

PubMed

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

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

2015-02-01

75

Snowfall in the Himalayas: an uncertain future from a little-known past  

NASA Astrophysics Data System (ADS)

Snow and ice provide large amounts of meltwater to the Indus, Ganges and Brahmaputra rivers. This study combines present-day observations and reanalysis data with climate model projections to estimate the amount of snow falling over the basins today and in the last decades of the 21st century. Estimates of present-day snowfall based on a combination of temperature and precipitation from reanalysis data and observations, vary by factors of 2-4. The spread is large, not just between the reanalysis and the observations, but also between the different observational data sets. With the strongest anthropogenic forcing scenario (RCP 8.5), the climate models project reductions in annual snowfall by 30-50% in the Indus Basin, 50-60% in the Ganges Basin and 50-70% in the Brahmaputra Basin, by 2071-2100. The reduction is due to increasing temperatures, as the mean of the models show constant or increasing precipitation throughout the year in most of the region. With the strongest anthropogenic forcing scenario, the mean elevation where rain changes to snow - the rain/snow line - creeps upward by 400-900 m, in most of the region by 700-900 m. The largest relative change in snowfall is seen in the upper, westernmost sub-basins of the Brahmaputra. With the strongest forcing scenario, most of this region will have temperatures above freezing, especially in the summer. The projected reduction in annual snowfall is 65-75%. In the upper Indus, the effect of a warmer climate on snowfall is less extreme, as most of the terrain is high enough to have temperatures sufficiently far below freezing today. A 20-40% reduction in annual snowfall is projected.

Viste, E.; Sorteberg, A.

2015-01-01

76

Increase of organochlorines and MFO activity in water birds wintering in an Italian lagoon  

Microsoft Academic Search

The Black-necked grebe (Podiceps nigricollis) is a migratory and dispersive birds species. Its breeding areas are located in central and eastern Europe; its wintering quarters are in western Europe, around the Mediterranean, Adriatic, Black and Caspian Seas. Recently Focardi et al. (1984) have reported that specimens of Black-necked grebes accumulate polychlorinated biphenyls and mercury in their tissues during their wintering

C. Fossi; C. Leonzio; S. Focardi

1986-01-01

77

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

78

Synoptic reasons for heavy snowfalls in the Polish German lowlands  

NASA Astrophysics Data System (ADS)

Daily circulation patterns responsible for heavy snowfalls in the Polish German lowlands were analysed. Composite maps of sea level pressure (SLP) and 500 hPa geopotential height means and anomalies were constructed for the days with an increase in snow cover depth by ?5 cm. Contour maps show negative anomalies of SLP and 500 hPa level over central Europe, indicating a low pressure system. Strong positive anomalies of SLP appear over Scandinavia and the northern Atlantic with the centre of positive anomalies located over Iceland. Weaker negative anomalies are observed in the Azores region. This confirms the strong negative correlation between snow cover appearance and the North Atlantic Oscillation index in Europe. The days with heavy snowfalls were clustered using the Ward’s method. Three types of circulation patterns were distinguished, each of them characterised by a low pressure system over central Europe. Type 3 represents the northern position of the low with its centre over the Baltic Sea, Type 2 shows the southern position of the low with its centre over the Adriatic and the Ionic Sea and Type 1 represents the low location between the two previous patterns with a wide meridional trough over the Atlantic.

Bednorz, E.

2008-05-01

79

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

80

Climatic Warming Increases Winter Wheat Yield but Reduces Grain Nitrogen Concentration in East China  

PubMed Central

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. PMID:24736557

Deng, Aixing; Song, Zhenwei; Zhang, Baoming; Zhang, Weijian

2014-01-01

81

Lessons learnt from the snow emergency management of winter season 2008-2009 in Piemonte  

Microsoft Academic Search

The winter season 2008-2009 has been characterized by heavy snowfalls over the western Alps. The snowfalls have been exceptional because of their earliness, persistence, intensity and territorial spread. 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

R. Pelosini; S. Bovo; M. Cordola

2011-01-01

82

Ubiquity of biological ice nucleators in snowfall.  

PubMed

Despite the integral role of ice nucleators (IN) in atmospheric processes leading to precipitation, their sources and distributions have not been well established. We examined IN in snowfall from mid- and high-latitude locations and found that the most active were biological in origin. Of the IN larger than 0.2 micrometer that were active at temperatures warmer than -7 degrees C, 69 to 100% were biological, and a substantial fraction were bacteria. Our results indicate that the biosphere is a source of highly active IN and suggest that these biological particles may affect the precipitation cycle and/or their own precipitation during atmospheric transport. PMID:18309078

Christner, Brent C; Morris, Cindy E; Foreman, Christine M; Cai, Rongman; Sands, David C

2008-02-29

83

Development of a snowfall retrieval algorithm at high microwave frequencies  

Microsoft Academic Search

A snowfall retrieval algorithm based on Bayes' theorem is developed using high-frequency microwave satellite data. In this algorithm, observational data from both airborne and surface-based radars are used to construct an a priori database of snowfall profiles. These profiles are then used as input to a forward radiative transfer model to obtain brightness temperatures at high microwave frequencies. In the

Yoo-Jeong Noh; Guosheng Liu; Eun-Kyoung Seo; James R. Wang; Kazumasa Aonashi

2006-01-01

84

An evaluation of the Wyoming Gauge System for snowfall measurement  

Microsoft Academic Search

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

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

2000-01-01

85

Future Changes in Northern Hemisphere Snowfall JOHN P. KRASTING  

E-print Network

Future Changes in Northern Hemisphere Snowfall JOHN P. KRASTING Department of Environmental Science 29 November 2012, in final form 16 April 2013) ABSTRACT Using simulations performed with 18 coupled), projections of the Northern Hemisphere snowfall under the representative concentration pathway (RCP4

Broccoli, Anthony J.

86

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

NASA Astrophysics Data System (ADS)

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 <1 to >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 pathways associated with changing subsurface hydrology in watersheds underlain by thawing permafrost.

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

2012-12-01

87

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

PubMed

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

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

2013-02-01

88

Increase of organochlorines and MFO activity in water birds wintering in an Italian lagoon  

SciTech Connect

The Black-necked grebe (Podiceps nigricollis) is a migratory and dispersive birds species. Its breeding areas are located in central and eastern Europe; its wintering quarters are in western Europe, around the Mediterranean, Adriatic, Black and Caspian Seas. Recently Focardi et al. (1984) have reported that specimens of Black-necked grebes accumulate polychlorinated biphenyls and mercury in their tissues during their wintering in the Northern Adriatic lagoon of Marano. Residues of some chlorinated hydrocarbons and the levels of the mixed function oxidases (one of the most efficient hepatic detoxication systems) have been evaluated in specimens of Black-necked grebes collected in the lagoon of Marano during the wintering period (October and December 1984; April 1985) and are the subject of this report.

Fossi, C.; Leonzio, C.; Focardi, S.

1986-10-01

89

Can supplemental food increase winter survival of a threatened cottontail rabbit?  

Microsoft Academic Search

Populations of New England cottontails (Sylvilagus transitionalis) have declined substantially in recent decades in response to habitat loss and fragmentation. Among some remnant populations, cottontails occupy small patches of thicket habitat where they experience high mortality rates as a consequence of limited food during winter. This limitation causes rabbits to forage away from cover where they are exposed to predators.

T. Weidman; J. A. Litvaitis

2011-01-01

90

Measuring winter precipitation in a mountain catchment  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

91

Snowfall-Driven Growth in East Antarctic Ice Sheet Mitigates Recent Sea-Level Rise  

Microsoft Academic Search

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

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

2005-01-01

92

Recent variations of snow cover and snowfall in North America and their relation to precipitation and temperature variations  

SciTech Connect

Contemporary large-scale changes in solid and total precipitation and satellite-derived snow cover were examined over the North American continent. Annual snow cover extent over the last 19 years decreased up to 6 [times] 10[sup 5] km[sub 2] relative to a 0.93[degrees]C (0.33[degrees]C) increase in North American (Northern Hemisphere) temperature. A strong correlation exists between snow cover and temperature where up to 78% of the variance in regional snow cover and snowfall is explained by the anomalies of monthly mean maximum temperature. Over the last two decades the decrease in snow cover during winter (December-March) has largely occurred through reduced frequency of snow cover in areas that typically have a high probability of snow on the ground with little change in the frequency of snow cover in other areas. Similar characteristics were observed during spring (April-May) in areas with high snow cover probability except for an expansion of the snow-free regions. Anomalies in these two seasons dominate the interannual variability (nearly three-fourths of the variance) of snow cover. 48 refs., 15 figs., 10 tabs.

Karl, T.R.; Groisman, P.Ya.; Knight, R.W.; Heim, R.R. Jr. (National Climatic Data Center, Asheville, NC (United States))

1993-07-01

93

Winter peaks of methylmercury in deposition to a remote Scottish mountain lake.  

PubMed

Depositional records of methylmercury (MeHg) are rare, especially for remote and mountainous areas. Our data from Lochnagar, a mountain lake in Scotland, covering a 7-year period from 2001-2008, show an unusual seasonal pattern in that elevated MeHg concentrations occur each winter while concentrations each summer fall below the limit of detection. To our knowledge this is the first time this seasonal pattern has been reported. Peak concentrations at the site in October 2006 (1.2 ng L(-1)) are amongst the highest reported depositional values in the literature. As the soils and lakes in the region are frozen or snow covered for much of each winter, we consider possible sources of this winter deposited MeHg to be either aqueous phase methylation in the atmosphere or marine evasion. However, the factor driving this seasonal pattern is likely to be scavenging by snow, as elevated concentrations in deposition coincide with periods of snowfall at the site. If this mechanism is correct, then predicted impacts of climate change, which will reduce annual snowfall at the site by between 50% and 100% by 2080, will effectively eliminate this input source. However, other climate-influenced inputs of mercury, such as remobilisation from catchment soils, are likely to increase and negate any benefit. PMID:23123118

Rose, Neil L; Munthe, John; McCartney, Alistair

2013-01-01

94

Improved frost tolerance and winter hardiness in proline overaccumulating winter wheat mutants obtained by in vitro-selection is associated with increased carbohydrate, soluble protein and abscisic acid (ABA) levels  

Microsoft Academic Search

In previous studies in vitro-selection of proline overaccumulating lines of winter wheat (Triticum sativum L. cv. Jo 3063) with increased frost tolerance was reported. These traits were found to be genetically stable. In the present\\u000a study the improvement of frost tolerance (winter hardiness) under field conditions is confirmed for F7 progenies of the mutants. Moreover, the mutants accumulated higher levels

Karl Dörffling; Helga Dörffling; Edgar Luck

2009-01-01

95

Snowfall induced severe pile-ups in southern Finland on 17 March 2005  

NASA Astrophysics Data System (ADS)

Weather has a great impact on road traffic and several studies have shown that accident risk increases especially during wintry weather conditions. Heavy snowfall, rain or sleet on an icy road surface and formation of hoar frost can make the driving conditions hazardous. Poor visibility, caused by snowfall or dense fog can increase the accident risk significantly and severe pile-ups on highways are possible. The risk for accidents increases, when many drivers can't adjust their speed to the worsening driving conditions even though the hazard is visible. This study presents a severe pile-up case that occurred in southern Finland near Helsinki city on Thursday 17 March 2005. Before this occasion, cold and clear weather prevailed for many days and the driving conditions were mostly fair. On 17 March a low pressure was approaching southern Finland from west. Light snowfall reached the Helsinki metropolitan area early in the morning and it was followed by a band of dense snowfall. During the rush hours, just before 0800 h, pile-ups occurred on four separate highways near Helsinki city almost at the same time (within about ten minutes). In total, almost 300 cars were crashed, 3 persons died and more than 60 persons got injured. The occurrence of dense snowfall during the rush hours had a great impact on driving conditions. The drivers heading towards Helsinki from north or northeast drove at first in clear, dry conditions, with only local light snowfall. But the sudden worsening of weather (and visibility) was a surprise for many although warnings for poor driving conditions were issued the previous evening on radio and TV. In addition to this, automatic vehicle speed measurements showed that the mean speed that morning was only a few km/h lower than on a normal day. When studying the weather situation, it appeared that near the surface there was a thin layer of cold air (2 m temperature being -5…-8 degrees) and warmer air above it. In this kind of situation super cooled water can exist in the lower troposphere, and this was also supported by dual-polarization radar observations. This fact might have had a positive impact on the slipperiness of the roads, although freezing drizzle was mainly observed only just after the passage of the dense snowfall and occurrence of the crashes. Due to low surface temperature, preventative anti-icing with salting could not be carried out early that morning (except for the western part of the area). So the snow got packed on the road surface by traffic, causing slippery conditions. In a case like this, real-time warning methods and changing speed limits could be the main way to prevent massive accidents. Dense observation network consisting of road weather observations (including visibility) and radar data should be utilized in the real-time warnings. Dense snowfall is a substantial risk for traffic on highways and severe pile-ups have occurred lately for example in Czech Republic and Austria (during March 2008).

Juga, I.; Hippi, M.

2009-09-01

96

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

NASA Astrophysics Data System (ADS)

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.

Milligan, William James, IV

97

Heat shock induces production of reactive oxygen species and increases inner mitochondrial membrane potential in winter wheat cells.  

PubMed

Heat shock leads to oxidative stress. Excessive ROS (reactive oxygen species) accumulation could be responsible for expression of genes of heat-shock proteins or for cell death. It is known that in isolated mammalian mitochondria high protonic potential on the inner membrane actuates the production of ROS. Changes in viability, ROS content, and mitochondrial membrane potential value have been studied in winter wheat (Triticum aestivum L.) cultured cells under heat treatment. Elevation of temperature to 37-50°C was found to induce elevated ROS generation and increased mitochondrial membrane potential, but it did not affect viability immediately after treatment. More severe heat exposure (55-60°C) was not accompanied by mitochondrial potential elevation and increased ROS production, but it led to instant cell death. A positive correlation between mitochondrial potential and ROS production was observed. Depolarization of the mitochondrial membrane by the protonophore CCCP inhibited ROS generation under the heating conditions. These data suggest that temperature elevation leads to mitochondrial membrane hyperpolarization in winter wheat cultured cells, which in turn causes the increased ROS production. PMID:25540005

Fedyaeva, A V; Stepanov, A V; Lyubushkina, I V; Pobezhimova, T P; Rikhvanov, E G

2014-11-01

98

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

99

Coupled Model Simulation of Snowfall Events Over the Black Hills  

NASA Technical Reports Server (NTRS)

Although many long-term simulations of snow accumulation and oblation have been made using stand-alone land surface models and surface models coupled with GCMs, less research has focused on short-term event simulations. Actually, accurate event simulations of snow-related processes are the basis for successful long-term simulation. Three advantages of event simulations of snowfall and snow melting are availability of: (1) intensive observation data from field experiments for validation; (2) more physically-realistic precipitation schemes for use in atmospheric models to simulate snowfall; and (3) a more detailed analysis of the snow melting processes. In addition to the complexities of snow related processes themselves, terrain-induced effects on snowfall/snow melting make simulations of snow events more difficult. Climatological observations indicate that terrain features such as the Black Hills of South Dakota and Wyoming can exert important effects on snow accumulation and snow oblation processes. One of the primary effects is that the orography causes forced uplift of airflow and causes atmospheric waves to form both upwind and downwind of it. Airflow often splits around the obstacle, converging on the lee side. This convergence may lead to precipitation enhancement. It also provides an elevated heat and moisture source that enhances atmospheric instability. During the period of April 5-May 5, 1999, the Upper Missouri River Basin Pilot Project (UMRBPP) made intensive observations on precipitation events occurring in the Black Hills. Two moderate snowfall events were captured during the period. The resulting high temporal and spatial resolution data provides opportunities to investigate terrain effects on snowfall amount, distribution, and melting. Successful simulation of snowfall amount, distribution, and evolution using atmospheric models is important to subsequent modeling of snow melting using snow sub-models in land surface schemes. In this paper, a coupled model system, consisting of an atmosphere model (ARPS) and a land-surface model (revised NCAR LSM), is used to simulate one of these UMRBPP cases.

Wang, Jianzhong; Hjelmfelt, M. R.; Capehart, W. J.

2000-01-01

100

INCIDENCE OF PLAGUE ASSOCIATED WITH INCREASED WINTER-SPRING PRECIPITATION IN NEW MEXICO  

Microsoft Academic Search

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

ROBERT R. PARMENTER; EKTA PRATAP YADAV; CHERYL A. PARMENTER; PAUL ETTESTAD; KENNETH L. GAGE

101

Spatialtemporal features of intense snowfall events in China and their possible change  

E-print Network

Spatialtemporal features of intense snowfall events in China and their possible change Jianqi Sun,1 snowfall event (ISE) in China are investigated over the period of 1962­2000. The results indicate. Wang, W. Yuan, and H. Chen (2010), Spatialtemporal features of intense snowfall events in China

102

A physical model to estimate snowfall over land using AMSU-B observations  

E-print Network

A physical model to estimate snowfall over land using AMSU-B observations Min-Jeong Kim,1,2 J. A a physical model to retrieve snowfall rate over land using brightness temperature observations from NOAA at all five frequencies. Retrieved snowfall rates compare favorably with the near-concurrent National

Houze Jr., Robert A.

103

Climate change projection of snowfall in the Colorado River Basin using dynamical downscaling  

E-print Network

Climate change projection of snowfall in the Colorado River Basin using dynamical downscaling] Recent observations show a decrease in the fraction of precipitation falling as snowfall in the western the simulated spatiotemporal variability of snowfall in the historical period when compared to observations

Castro, Christopher L.

104

Spaceborne Passive Microwave Measurement of Snowfall over Land Min-Jeong Kim  

E-print Network

Spaceborne Passive Microwave Measurement of Snowfall over Land Min-Jeong Kim Department, 156-720, Korea Abstracts A physically based retrieval algorithm was developed to estimate snowfall snowfall distribution was validated with radar reflectivity measurements obtained from the operational NWS

Houze Jr., Robert A.

105

NOTES AND CORRESPONDENCE Improving Snowfall Forecasting by Accounting for the Climatological Variability of  

E-print Network

NOTES AND CORRESPONDENCE Improving Snowfall Forecasting by Accounting for the Climatological received 30 August 2004, in final form 26 May 2005) ABSTRACT Accurately forecasting snowfall is a challenge ratio is the ratio of snowfall to liquid equivalent and is inversely proportional to the snow density

Schultz, David

106

Water Vapor Transport Paths and Accumulation during Widespread Snowfall Events in Northeastern China  

E-print Network

Water Vapor Transport Paths and Accumulation during Widespread Snowfall Events in Northeastern transport (WVT) and its role in supplying moisture for widespread snowfall (WS) events in northeastern China November through March, widespread snowfall (WS) is one of the most important synoptic phenomena, impacting

107

Lidar-Radar Measurements of Snowfall Edwin W. Eloranta--Univ. Of Wisconsin  

E-print Network

Lidar-Radar Measurements of Snowfall Edwin W. Eloranta--Univ. Of Wisconsin Aerodynamic flow around gauges and the horizontal transport of windblown snow along the surface produce errors in snowfall in the high Arctic where snowfall amount are very low and blowing snow is frequent. This paper describes

Eloranta, Edwin W.

108

SATELLITE PERSPECTIVES ON THE SPATIAL EXTENT OF NEW SNOWFALL IN THE SOUTHERN APPALACHIAN MOUNTAINS  

E-print Network

SATELLITE PERSPECTIVES ON THE SPATIAL EXTENT OF NEW SNOWFALL IN THE SOUTHERN APPALACHIAN MOUNTAINS and Planning #12;SATELLITE PERSPECTIVES ON THE SPATIAL EXTENT OF NEW SNOWFALL IN THE SOUTHERN APPALACHIAN ON THE SPATIAL EXTENT OF NEW SNOWFALL IN THE SOUTHERN APPALACHIAN MOUNTAINS. (May 2013) Johnathan W. Sugg B

109

SNOWFALL EVENT CHARACTERISTICS FROM A HIGH-ELEVATION SITE IN THE SOUTHERN APPALACHIAN MOUNTAINS  

E-print Network

SNOWFALL EVENT CHARACTERISTICS FROM A HIGH-ELEVATION SITE IN THE SOUTHERN APPALACHIAN MOUNTAINS of Geography and Planning #12; SNOWFALL EVENT CHARACTERISTICS FROM A HIGH-ELEVATION SITE IN THE SOUTHERN SNOWFALL EVENT CHARACTERISTICS FROM A HIGH-ELEVATION SITE IN THE SOUTHERN APPALACHIAN MOUNTAINS Daniel T

110

Computational Procedures for the 1981-2010 Normals: Precipitation, Snowfall, and Preliminary Documentation  

E-print Network

Computational Procedures for the 1981-2010 Normals: Precipitation, Snowfall, and Snow Depth include a suite of descriptive statistics based on precipitation, snowfall, and snow depth measurements of precipitation and snowfall serve as basic descriptors of a location's climate. Daily relative frequencies

111

Variability and trends of total precipitation and snowfall over the United States and Canada  

Microsoft Academic Search

The biases and large-scale inhomogeneities in the time series of measured precipitation and snowfall over the United States and Canada are discussed and analyzed. The spatial statistical characteristics of monthly and annual snowfall and total precipitation are investigated and parameterized. After adjustments and selection of the best' network, reliable first guess' estimates of North American snowfall and precipitation are obtained.

Pavel Ya Groisman; David R. Easterling

1994-01-01

112

Determination of maritime snowfall from radar and microwave radiometer measurements  

NASA Technical Reports Server (NTRS)

This study examines the effect of snowfall on high frequency microwave radiances measured from above the atmosphere by airborne radiometers. Attention is given to the analysis of a maritime snow storm so that snow accumulation on the surface would not introduce ambiguities into the analysis of the upwelling radiances.

Weinman, James A.; Hakkarinen, Ida M.

1990-01-01

113

On the evolution of the snow surface during snowfall  

Microsoft Academic Search

The deposition and attachment mechanism of settling snow crystals during snowfall dictates the very initial structure of ice within a natural snowpack. In this letter we apply ballistic deposition as a simple model to study the structural evolution of the growing surface of a snowpack during its formation. The roughness of the snow surface is predicted from the behaviour of

H. Löwe; L. Egli; S. Bartlett; M. Guala; C. Manes

2007-01-01

114

Characterization of snowfall via field observations and nearby atmospheric soundings  

NASA Astrophysics Data System (ADS)

Snowfall is characterized through precipitation rate and depth of water after melting in a standard cylindrical gauge. The rates of snowfall are related to microphysical and dynamical processes in weather systems and are further specified by choice of measurement time, a minimum related to the statistics of individual falling particles. Origins of snowflakes at the surface and their growth aloft are inferred from the individual size, shape, concentration and fall of individual particles and of aggregates. Data collected enhances understanding of mixed-phase cloud dynamics. An ice particle is definable as a single crystal, having long range order in the crystal lattice or as polycrystal particles having a multitude of individual single crystals held together though interlocking shapes as a snowflake. Identifying the number of individual ice crystals requires a degree of persistence and skill, is not readily automated, and is capable of providing key information on the origin and growth history of particles, not obtainable by other means. Composite snowflakes are collected on a black cloth, with a scale, and photographed. Individual ice crystals are identified, counted, and related to the snowfall rate leading to a calculation of the individual ice crystal number flux. The snowfall rate is characterized as a concentration and an inferred flux of individual nucleation events to be related to possible direct nucleation and secondary ice formation aloft; accumulation rate thru hotplate measurements. Atmospheric soundings produced by the NWS Reno station, about two miles from the observation site, aides in the nucleation event approximations.

Francisco, D.; Hallett, J. N.

2011-12-01

115

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

NASA Astrophysics Data System (ADS)

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

Chang, E. K.

2013-12-01

116

Increase in body size is correlated to warmer winters in a passerine bird as inferred from time series data  

PubMed Central

Climate change is expected to affect natural populations in many ways. One way of getting an understanding of the effects of a changing climate is to analyze time series of natural populations. Therefore, we analyzed time series of 25 and 20 years, respectively, in two populations of the citril finch (Carduelis citrinella) to understand the background of a dramatic increase in wing length in this species over this period, ranging between 1.3 and 2.9 phenotypic standard deviations. We found that the increase in wing length is closely correlated to warmer winters and in one case to rain in relation to temperature in the summer. In order to understand the process of change, we implemented seven simulation models, ranging from two nonadaptive models (drift and sampling), and five adaptive models with selection and/or phenotypic plasticity involved and tested these models against the time series of males and females from the two population separately. The nonadaptive models were rejected in each case, but the results were mixed when it comes to the adaptive models. The difference in fit of the models was sometimes not significant indicating that the models were not different enough. In conclusion, the dramatic change in mean wing length can best be explained as an adaptive response to a changing climate. PMID:25628864

Björklund, Mats; Borras, Antoni; Cabrera, Josep; Senar, Juan Carlos

2015-01-01

117

Using a Snow Drift Model to simulate Aeolian Drift and Snowfall on the Summit of1 Mauna Kea, Hawaii 2  

E-print Network

Revised Using a Snow Drift Model to simulate Aeolian Drift and Snowfall on the Summit of1Model, a spatially16 distributed snow-evolution model, is used to construct snowfall and bug-fall17 of snowfall and bug fall, presented in this study. For the snowfall maps,25 only weather data from days

Businger, Steven

118

Are the Two Most Recent Harsh Northern Hemisphere Winters Manifestation of Anthropogenic Global Warming in the Arctic?  

NASA Astrophysics Data System (ADS)

The global climate models predict that temperatures will warm the greatest in winter due to a positive feedback of increased greenhouse gases (GHGs) and a diminished and darker cryosphere. However, headlines on the two most recent years have been less about the extreme warmth and more about the severity of winter weather and record snowfalls. What dynamic forcings could contribute to reversing the radiative warming forced by both increased GHGs and decreased planetary albedo resultant of a shrinking cryopshere? Furthermore, current consensus on global climate change predicts warming trends over the NH continents during boreal winter. However, recent trends in Northern Hemisphere (NH) seasonal surface temperatures diverge from these projections. For the last two decades, NH landmasses have experienced significant warming trends for all seasons except winter, when large-scale cooling trends exist instead. The surface temperature trend pattern is most closely associated with the negative polarity of the Northern Annular Mode (NAM), which has been linked with leading stratospheric circulation anomalies. These circulation anomalies are, in turn, linked with increasing Eurasian snow cover in the fall; an observed increasing trend in Eurasian snow cover, in part forced by a warming Arctic is the most likely boundary condition for partially forcing winter hemispheric trends over the past two decades that has heretofore been identified. We will also compare the trend analysis with the NAM to trend analysis with varying sea surface temperatures associated with El Nino/Southern Oscillation, the Pacific Decadal Oscillation, the Atlantic Multidecadal Oscillation, solar variability and diminishing Arctic sea ice.

Cohen, J. L.; Furtado, J. C.; Barlow, M. A.; Alexeev, V. A.; Cherry, J. E.

2011-12-01

119

Nutrition for winter sports  

Microsoft Academic Search

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

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

2011-01-01

120

A Winter's Tale  

NSDL National Science Digital Library

This resource explores winter weather and frozen precipitation. The page on precipitation points out that snow and rain are both water and explains how the different forms of frozen precipitation (snow, sleet, freezing rain) occur. There is a page on cirrus clouds that explains their characterstics and how they may affect climate by reflecting solar radiation or reducing outgoing infrared energy from Earth. The Jet Stream page explains the characteristics of these high-speed rivers of air, including what causes them and their effect on weather and climate. There is also a feature on the esthetic wonders of frozen water, including halos produced by ice crystals in the air, sparkling of snowflakes, why fresh snow squeaks when stepped on, and why it is silent during a snowfall. A bibliography is also provided.

121

Evaluation of trends in derived snowfall and rainfall across Eurasia and linkages with discharge to the Arctic Ocean  

Microsoft Academic Search

To more fully understand the role of precipitation in observed increases in freshwater discharge to the Arctic Ocean, data from a new archive of bias-adjusted precipitation records for the former USSR (TD9813), along with the CRU and Willmott-Matsuura data sets, were examined for the period 1936-1999. Across the six largest Eurasian river basins, snowfall derived from TD9813 exhibits a strongly

M. A. Rawlins; C. J. Willmott; A. Shiklomanov; E. Linder; S. Frolking; R. B. Lammers; C. J. Vörösmarty

2006-01-01

122

Effect of sea surface temperature errors on snowfall1 in WRF: a case study of a heavy snowfall event in2  

E-print Network

32 simulations were run for the Yellow Sea during December 2012, when a severe33 snowfall occurred. The changes in surface air temperature over39 the Yellow Sea were positively correlated with a warm (or cold surface temperature, Snowfall, WRF, Yellow Sea, OSTIA49 #12;3 1. Introduction50 Sea surface temperature

Park, Rokjin

123

Observation of snowfall over land by microwave radiometry from space  

Microsoft Academic Search

High frequency (?>100 GHz) observations from AMSU-B during the March 5-6, 2001 New England blizzard are used to investigate the detection of snowfall over land. The AMSU-B data are compared to NEXRAD reflectivities. The radiative effects of a snow model are compared with observations. Low altitude water vapor is shown to obscure emission from the underlying ground at high frequencies,

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

2002-01-01

124

Effect of summer snowfall on glacier mass balance  

Microsoft Academic Search

It has been postulated that heavy summer snowfalls have a large impact\\u000aon the mass balance of mid-latitude glaciers, because they simultaneously add mass to the\\u000aglacier and reduce the amount of absorbed solar radiation. An automatic weather station\\u000a(AWS) on the snout of Morteratschgletscher, Switzerland, registered a large summer\\u000asnowfall event on 10-11 July 2000. Sonic rangers recorded about

Johannes Oerlemans

2004-01-01

125

Chemical composition of fresh snowfalls at Palmer Station, Antarctica  

Microsoft Academic Search

A first time investigation was performed to establish a chemical baseline for snowfall at Palmer Station Antarctica (64°46?S, 64°05?W) since there was no such record. A chemical baseline for snow could be use to validate climate change studies based on ice core analyses. The snow samples contained (from high to low mass concentration) total organic carbon, chloride, inorganic carbon, sodium,

T. P. DeFelice

1998-01-01

126

Snowfall Characterization by Field Observation and Atmospheric Sounding  

NASA Astrophysics Data System (ADS)

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

Francisco, Dianna M.

127

Ternary forecast of heavy snowfall in the Honam area, Korea  

NASA Astrophysics Data System (ADS)

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

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

2009-03-01

128

Measurement and simulation of the effect of snowfall on free-space optical propagation.  

PubMed

We measured the time variation of a received laser signal level during snowfall over a distance of 72 m. The signal level dropped sharply for up to 10 ms when a snowflake crossed the laser beam. The probability distribution of the variation due to snowfall was calculated by assuming it to be the linear superposition of the light diffracted by snowflakes. The measured distributions could be reproduced by assuming reasonable snowflake size distributions. Furthermore, the probability distributions due to snowfall over a 1 km distance were calculated, and the expected bit errors during snowfall and the transmitted beam sizes were evaluated. PMID:19122713

Akiba, Makoto; Ogawa, Kayo; Wakamori, Kazuhiko; Kodate, Kashiko; Ito, Shigeo

2008-11-01

129

Lake-Effect Snowfall over Lake Michigan  

Microsoft Academic Search

Aircraft measurements of snow particle size spectra from 36 flights on 26 snowy days are used to estimate snow precipitation rates over Lake Michigan. Results show that average rates during 14 wind-parallel-type lake-effect storms increased from the upwind shore to about midlake and then were essentially uniform (1.5 2 mm day1, liquid water equivalent) to the downwind shore. Snow from

Roscoe R. Braham Jr.; Maureen J. Dungey

1995-01-01

130

Winter Storm  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. Does increased humidity usually increase of decrease your chances for rain? 4. What happens when there is ...

Sarah

2009-09-28

131

Clover cover crops under-sown in winter wheat increase yield of subsequent spring barley—Effect of N dose and companion grass  

Microsoft Academic Search

Four two-year field trials, arranged in randomised split-plots, were carried out in southern Sweden with the aim of determining whether reduced N fertiliser dose in winter wheat production with spring under-sown clover cover crops, with or without perennial ryegrass in the seed mixture, would increase the clover biomass and hence the benefits of the cover crops in terms of the

Göran Bergkvist; Maria Stenberg; Johanna Wetterlind; Birgitta Båth; Sara Elfstrand

2011-01-01

132

Lawn Winterization  

NSDL National Science Digital Library

Contrary to what many people think, Fall is the time of year when your turf needs attention. The following three steps need to be completed before the first snowfall: Apply Fertilizer Lower Mower Height Drain Secondary Water System Fall fertilization is best because the lawn has passed through the stressful summer months and needs to rebuild itself. Fall Lawn Care Guide ...

Miss Melrose

2006-10-13

133

Damage and compensatory effects of winter drought on winter wheat  

Microsoft Academic Search

Field experiments were carried out to investigate the damage and compensatory effects of winter drought on winter wheat. The results of the study show that, after winter drought, the growth and development of winter wheat, display obviously dual effects of damage and compensatory. The productive tiller percentage increases while spike number per hectare reduces. Plant height does not change significantly,

Xiu-Shan Tan; Bao-Xing Ye; Jian-Jie Bi

2011-01-01

134

Sensitivity of an energy balance climate model with predicted snowfall rates  

NASA Technical Reports Server (NTRS)

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

Bowman, K. P.

1985-01-01

135

Rapid increase deposition of Anthropogenic Aerosols in Southeast Tibetan Glacier  

NASA Astrophysics Data System (ADS)

Since the so-called Asian Brown Cloud (ABC) occurred during dry season was coined by the international program of Indian Ocean Experiment (INDOEX) in 1999, it has received special attention due to its high loading of anthropogenic aerosols which may have important climatic and environmental effects, especially on accelerating glacier retreat in Himalayas. Yet little is known about its concentrations in the Himalayan snow. Measurements of elemental carbon (EC), water insoluble organic carbon (WIOC) and water soluble ions in a very high resolution snow/firn core from Southeastern Tibetan Plateau indicate that anthropogenic aerosols concentrations increased rapidly in the last 8-year, such as EC, WIOC and SO42- concentrations in the core were 5.3, 56.6 and 4.1 ng g-1 in 1998, but rapid increased to 15.8, 135.6 and 161.2 ng g-1 in 2005, respectively. EC concentrations and EC/WIOC ratios show large seasonal variations, in non-monsoon precipitation are more than double of that in monsoon snowfall. Since the snow cover extends to a larger area in winter and spring on the Tibetan Plateau, the high EC concentration in this seasonal snowfall will induce an advanced snow melting and an enhanced radiation forcing in spring through absorbing more radiation and change the seasonal water supply for South and East Asia. So the increasing trend of EC concentration in snowfall may cause an enhancing impact on Tibetan glacier retreat, snow and permafrost melting, and alter ulteriorly the atmospheric circulation over half the planet via the pivotal role of the aerial Tibetan Plateau.

Wang, M.; Xu, B.; Cao, J.

2008-12-01

136

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

Microsoft Academic Search

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

Peter V. Hobbs; L. F. Radke

1973-01-01

137

Atmospheric circulation patterns related to heavy snowfall days in Andorra, Pyrenees  

Microsoft Academic Search

Heavy snowfalls over mountain regions are often a direct cause of avalanches. Specific synoptic-scale atmospheric situations are responsible for these kinds of extreme snowfall event, and this is indeed the case for Andorra, a small country located in the Pyrenees, between France and Spain. Based on days with an intensity of at least 30 cm of snow in a 24

Pere Esteban; Philip D. Jones; Javier Martín-Vide; Montse Mases

2005-01-01

138

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

NASA Astrophysics Data System (ADS)

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 that could be useful to improve the snow emergency plan in Catalonia, released in 2004, and mitigating the effects of future snow storms. A campaign focused on motivate population in order to increase more social commitment in these events, seems to be necessary to prevent avoidable risks. Information campaigns and some educational tasks have to be carried out to make warnings and forecasts reports clearer to citizens and to increase population sensitivity in emergency situations.

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

2010-09-01

139

Chemical composition of fresh snowfalls at Palmer Station, Antarctica  

NASA Astrophysics Data System (ADS)

A first time investigation was performed to establish a chemical baseline for snowfall at Palmer Station Antarctica (64°46'S, 64°05'W) since there was no such record. A chemical baseline for snow could be use to validate climate change studies based on ice core analyses. The snow samples contained (from high to low mass concentration) total organic carbon, chloride, inorganic carbon, sodium, sulfate, magnesium, calcium, potassium, fluoride, ammonium, and nitrate, excluding hydrogen and hydroxide. The pH of these samples ranged between 4.0-6.2. The relatively low nitrate and relatively high sulfate concentrations found in our samples are consistent with the results of other studies for this region of Antarctica. The ions and pH do not appear to favor a particular wind direction during this period. The total deposition of sulfate and flouride via snowfall between 10 January and 10 February is conservatively estimated to be 4.78 and 1.3 kg km -2, respectively.

DeFelice, T. P.

140

Mesoscale Frequencies and Seasonal Snowfalls for Different Types of Lake Michigan Snow Storms.  

NASA Astrophysics Data System (ADS)

Members of the Cloud Physics Laboratory, University of Chicago, have identified three different mesoscale organization patterns of lake-effect snow storms over Lake Michigan: multiple wind-parallel bands, single midlake bands, and single shoreline bands. For the 70 snowfall seasons ending with 1980/81, Braham and Dungey estimated that lake-effect snows contributed 8% of the total snowfall along the west shore of the lake, and 39% along the east shore.In the present study daily GOES satellite images and daily snowfall records are used to find the seasonal snowfall in four geographical area from each type of lake-effect storm and from nonlake-effect storms, for the snowfall seasons 1978/79 and 1979/80. Over the two seasons, 176 snowfall days were identified. Of these, 52% were nonlake-effect and 48% were lake-effect days. Of the 84 lake-effect days, 51% had wind-parallel bands, 22% had midlake bands, 2% had shoreline bands, and 25% had undetermined lake-effect cloud types. Along the west shore of the lake, lake-effect snows contributed 29% of the total snowfall, primarily from midlake bands. Along the east shore, lake-effect storms contributed 50% of the total snowfall. About half of the lake-effect contribution on the east shore was from wind-parallel bands, with most of the remainder from midlake bands and undetermined convective types. Although individual shoreline bands may yield locally heavy snowfalls, their contribution in 1978/79 and 1979/80 was very small, probably due to their low frequency of occurrence and the localized nature of their snowfall.

Kelly, Robert D.

1986-03-01

141

6A.7 Regional Snowfall Impact Scale Michael F. Squires*, Jay H. Lawrimore, and Richard R. Heim Jr.  

E-print Network

6A.7 Regional Snowfall Impact Scale Michael F. Squires*, Jay H. Lawrimore, and Richard R. Heim Jr Renaissance Computing Institute, Asheville, NC 1. INTRODUCTION This paper describes a new regional snowfall Data Center. The Regional Snowfall Impact Scale (ReSIS) is based on the spatial extent of the storm

142

GEOPHYSICAL RESEARCH LETTERS, VOL. ???, XXXX, DOI:10.1029/, Future snowfall in western and central Europe projected with a  

E-print Network

GEOPHYSICAL RESEARCH LETTERS, VOL. ???, XXXX, DOI:10.1029/, Future snowfall in western and central and Erik van Meijgaard2 Snowfall frequency and intensity are influenced strongly by climate change. Here we, by focusing on snowfall on days where the mean temperature is below freezing (Hellmann days). Using

de Vries, Hylke

143

Snowfall Retrievals Using Millimeter-Wavelength Cloud Radars SERGEY Y. MATROSOV, MATTHEW D. SHUPE, AND IRINA V. DJALALOVA  

E-print Network

Snowfall Retrievals Using Millimeter-Wavelength Cloud Radars SERGEY Y. MATROSOV, MATTHEW D. SHUPE primarily for cloud studies can be also used effectively for snowfall retrievals. Radar reflectivity­liquid equivalent snowfall rate (Ze­S) rela- tions specifically tuned for Ka- and W-band radar frequencies

Shupe, Matthew

144

NOAA's 1981-2010 U.S. Climate Normals:2 Monthly Precipitation, Snowfall, and Snow Depth3  

E-print Network

1 1 NOAA's 1981-2010 U.S. Climate Normals:2 Monthly Precipitation, Snowfall, and Snow Depth3 4 Imke a suite of descriptive statistics based on precipitation, snowfall, and snow depth34 measurements and less total43 annual snowfall across much of the contiguous United States; wetter conditions over44 much

145

IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 42, NO. 5, MAY 2004 1047 A Physical Model to Determine Snowfall  

E-print Network

to Determine Snowfall Over Land by Microwave Radiometry Gail M. Skofronick-Jackson, Senior Member, IEEE, Min to frozen hydrometeors is signifi- cant. However, the scattering effect of snowfall in the atmosphere blizzard were used to retrieve snowfall over land. Vertical distributions of snow, temperature

Houze Jr., Robert A.

146

Development of the Pan-Arctic Snowfall Reconstruction: New Land-Based Solid Precipitation Estimates for 194099  

E-print Network

Development of the Pan-Arctic Snowfall Reconstruction: New Land-Based Solid Precipitation Estimates) ABSTRACT A new product, the Pan-Arctic Snowfall Reconstruction (PASR), is developed to address the problem employed for estimating pan-arctic snowfall. The NASA Interannual-to-Seasonal Prediction Project Catch

Dery, Stephen

147

Winter Wonderland  

NSDL National Science Digital Library

This data tip from Bridge, the Ocean Sciences Education Teacher Resource Center archive, includes a variety of educational sites to visit, and a data exercise on snowfall patterns using local data or historical data for Salt Lake City, Utah. Learners can also discover some of the water chemistry behind snow. The activity introduces the meteogram, a time cross-section of data for a specific surface reporting station. The data plotted include temperatures, winds, pressure, clouds and present weather.

148

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

NASA Technical Reports Server (NTRS)

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 assumptions.

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

2009-01-01

149

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

NASA Technical Reports Server (NTRS)

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 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 assumptions.

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

2009-01-01

150

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)

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 rapidly translated into streamflow values that approach significant flooding risks.

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

2014-05-01

151

Winters fuels report  

SciTech Connect

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

NONE

1995-10-27

152

THE INFLUENCE ON EMERGENCY VEHICLE CAUSED BY THE GUERRILLA HEAVY SNOWFALL AND CONSIDERATION ABOUT MEASURES  

NASA Astrophysics Data System (ADS)

In Nanao City, Ishikawa, it was a sudden snowfall (the following, "guerrilla heavy snowfall") in a short time in January, 2009, and a traffic jam occurred in the various places in city. Therefore, the snow removing was late, and the emergency transportation was late, too. So, Ishikawa Prefecture performed the review of the snow removing system with this guerrilla heavy snowfall as a lesson in the next year. As a result, in January, 2011, similar guerrilla heavy snowfall was generated, but the traffic jam in the city didn't occur that much, and the big hindrance didn't produce the delay of the emergency transportation either. Therefore, in this study, I analyzed the snowfall situation of the year before and after the snow removing system improvement, the traffic jam situation and snow removing dispatch data and compared the difference quantitatively. In addition, after guerrilla heavy snowfall, the study meeting the study meeting was held by prefecture, country, city, town and association of construction industry, and they built the area snow removing cooperation system, so I carried out an interview investigation about the real enforcement situation and progress.

Takahashi, Masanori; Takayama, Jun-Ichi; Nakayama, Shoichiro

153

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

PubMed Central

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

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

2014-01-01

154

Anomalous snowfall caused by natural-draft cooling towers  

SciTech Connect

Scattered reports of significant amounts of snow anomalously produced by cooling-tower plumes suggest that this process may be of importance. This conclusion is supported by study of high-resolution satellite images. Tabulation of a number of aerial observations of plumes at subfreezing temperatures indicates that a plume is likely to produce measurable snow if its temperature is colder than -13/sup 0/C and the saturation deficit of the ambient air is less than 0.5 g m/sup -3/. These factors are important because they affect the rates of nucleation and growth of ice particles. The rate of mixing between plume and ambient air is also important because it affects the rate of evaporation within the plume, which in turn determines the length of time available for snow particles to grow large enough to fall out. These empirically derived criteria were tested using a numerical model of cloud microphysics that simulates the most important processes of transfer of water substance between vapor, liquid, and ice, including nucleation and development of particle-size spectra. Dynamic processes were specified, not modeled. Among the many quantities computed is the flux density of snow at the base of the plume. From this, together with average fallspeed and horizontal wind speed, one can compute the amount and pattern of snowfall at the ground.

Koenig, L.R.

1980-05-01

155

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

PubMed

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 influence on wildlife range use. PMID:21915329

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

2011-01-01

156

High Frequency Microwave-based Snowfall Rate Estimation using an Artificial Neural Network Approach  

NASA Astrophysics Data System (ADS)

There are regions in the world with significant dependency on the melted water from accumulated snow to strive against freshwater resources scarcity. In the U.S, there are several states including California and Arizona where melting snow plays an important role to manage growing unmet freshwater demand. Nevertheless, an accurate estimate of snowfall is always a major challenge for water resources management communities. Arguably, ground-based gauges and radar have been utilized to measure snowfall. Considering the sparse network or lack of spatial coverage of ground-based instruments, it is required to deploy satellite-based technologies without existing ground-based sensors limitations and errors. Sensitivity of high frequency microwave (MW) range of electromagnetic to ice particles and snowflakes lead us to use satellite-based MW brightness temperature (BT) to estimate snowfall rate. To meet the main objective of this study that is using satellite-retrieved microwave signals to improve capability of snowfall rate estimation from space, we are developing a multi-frequency algorithm based on an artificial neural network (ANN) system. The developed algorithm will estimate snowfall rate using microwave frequencies from the Advanced Microwave Sounding Unit (AMSU)-B. The preliminary results show that any combination of MW channels including high frequency band of 183±7 GHz is more related to snowfall amount than the ones without this channel. These results also reveal the promising performance of the ANN-based models in the estimation of snowfall in higher latitude and mountainous regions with average correlation coefficient of 0.55 for independent validation cases.

Zahraei, A.; Hernandez, C.; Mahani, S. E.; Khanbilvardi, R.

2012-12-01

157

The Value of Snowfall to Skiers and Boarders  

Microsoft Academic Search

An interesting winter sport phenomenon inrecent years has been the growth ofsnowboarding. Snowboarding has outpaced skiingat many resorts and has become the snow ridingactivity of choice for many young people. Thisstudy develops an empirical demand model forwinter sport trips amongst college studentsfrom both camps and estimates economic welfareassociated with the two different activities. The results show that both trip demand

Jeffrey Englin; Klaus Moeltner

2004-01-01

158

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

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

159

Snow climate baseline conditions and trends in Croatia relevant to winter tourism  

NASA Astrophysics Data System (ADS)

The presence of snow along a portion of the Croatian highlands has enabled the development of winter tourism that is primarily oriented toward snow-related activities. Snow is more abundant and stays on the ground longer in the mountainous district of Gorski kotar (south eastern edge of the Alps) and on Mount Velebit (Dinaric Alps), which have elevations of up to 1,600 m and are close to the Adriatic coast than over the inland hilly region of north western Croatia where the summits are not more than approximately 1,000 m high. Basic information about the snow conditions at these locations was gathered for this study, including the annual cycle and probabilities for various snow parameters at different altitudes. As requested by the Croatian Ski Association, the relation between the air temperature and the relative humidity was investigated to determine the feasibility of artificial snowmaking. The snow parameters are highly correlated to air temperature, surface air pressure and precipitation, with certain differences occurring as a result of the altitude. Since the beginning of the second half of the twentieth century, winter warming and a significant increase in the mean air pressure (more anticyclonic situations) have been detected at all sites. Winter precipitation totals decreased at medium altitudes and increased at the summit of Mount Velebit, but these trends were not significant. The frequency of precipitation days and of snowfall decreased whereas an increasing fraction of the precipitation days at high altitudes involved solid precipitation. In contrast, a decreasing fraction of the precipitation days at medium altitudes involved solid precipitation, probably because of the different warming intensities at different altitudes. The mean daily snow depth and the duration of snow cover both slightly decreased at medium altitudes whereas the snow cover duration slightly increased at the mountainous summit of Mount Velebit.

Gaji?-?apka, M.

2011-08-01

160

Winter Festival.  

ERIC Educational Resources Information Center

This is one of a series of elementary readers written in Cantonese and English and designed to familiarize children with the traditional major Chinese festivals celebrated by the Chinese in America. This booklet describes the occasion for the Winter Festival (the beginning of winter) and follows a Chinese-American family in its preparation for and…

Lew, Gordon

161

Winter Wonderlands  

ERIC Educational Resources Information Center

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

Coy, Mary

2011-01-01

162

Summer C Fixation of Salix arctic is Altered by Prior Winter Snow Regimes: Photosynthetic Responses to Long-Term Snow Increases in the High Arctic of NW Greenland  

NASA Astrophysics Data System (ADS)

Climate models and snow measurements on Greenland show increased precipitation in addition to warming in the High Arctic. Because polar semi-deserts may be water limited, additional snow and snow melt water, may alleviate mid-summer drought and promote additional carbon fixation. We investigated the long-term (10 years of experimental snow increases) consequences of additional winter snow as it effects subsequent summer gas exchange of Salix arctica in a polar semi-desert tundra ecosystem in NW Greenland (76.6N, 68.6W). In 2011, measurements of gas exchange physiology were conducted along a transect from high to ambient snow accumulation in mid-July. In 2012, gas exchange was measured in high and ambient snow zones between late June and early August. In 2012, the seasonal patterns of ?18O of xylem water and soil water between 5 and 20 cm below the soil surface was measured to determine if snow accumulation influences the water sources and depth of water used by S. arctica. In 2011, photosynthesis in the deep snow zones was lower than in the ambient snow zone; similar results were observed for leaf N content. Carbon isotope composition (?13C) of S. arctica leaves did not differ between deep and ambient snow zones suggesting a similar season-long relationship between photosynthesis and stomatal conductance in both locations. In 2012, there was a trend towards higher photosynthesis at the height of the growing season in the deep snow zones. Light response curves in 2012 suggest higher maximum photosynthesis in the deep snow zones compared to the ambient zones. Regardless of prior winter snow accumulation, S. arctica appears to derive nearly all its xylem water from the top 5 cm of the soil. There is little evidence that differences in photosynthetic physiology result directly from increased soil moisture associated with high snow, rather the effect appears more complex. Much of the increased snow accumulation will run-off of these systems when the soils are still frozen in the spring. Rather, deeper snow may be changing the soil and plant N cycle and altering the availability of N to plants possibly through the delayed onset of the growing season in high snow zones compared to regions with ambient snow accumulation. Finally, we note that weather differed considerably between 2011 and 2012. In 2011, a typical summer dry period was observed such that soils dried considerably. During 2012, repeated precipitation events from mid-June to late July maintained high soil moisture content. It appears that additional snow accumulation effects on High Arctic plant C fixation may be complex and involve a combined effect on both soil water, soil and plant N dynamics, and the relative effects may be predicated by the quantity and timing of precipitation during the growing season.

Leffler, A.; Welker, J. M.; Sullivan, P. F.; Maseyk, K. S.

2012-12-01

163

MEASURING SNOWFALLS by Lowell L. Koontz http://members.cox.net/wxr/koontz.htm 1 of 4 1/4/06 11:01 AM  

E-print Network

MEASURING SNOWFALLS by Lowell L. Koontz http://members.cox.net/wxr/koontz.htm 1 of 4 1/4/06 11:01 AM MEASURING SNOWFALLS By Lowell L. Koontz Member, ACON - VA/NC/SC One of nature's phenomenon erratic or imprecise. The snowfall may be a new record for the area but can you be confident in your

Pasternack, Gregory B.

164

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

NASA Astrophysics Data System (ADS)

Snowfall is the dominant hydrologic input for high elevations and latitudes of the arid- and semi-arid western United States. Many climate models envision changes in California's Sierra Nevada snow pack characteristics, which would severely impact the storage and release of water for one of the world's largest economies. Climate change threatens the sustainability of this water supply through altered snowfall timing, reduced snowpack depth, changes in snow water equivalents, earlier snowmelt, and highly-uncertain but plausible scenarios of rain-on-snow events. Climate model scenarios envision reduced snow pack and earlier melt under a warmer climate, but how will these changes affect soil and plant water relations and ecosystem processes, such as carbon storage? To address this question, experiments utilize large-scale, long-term snow fences to manipulate snow depth and melt timing at a desert-montane ecotone in eastern California, USA. A combination of instantaneous gas exchange and water potential measurements, plant community surveys, annual ring growth increments, in situ instrumentation, and long-term snow course data were used to couple physical and biological processes at daily, monthly, annual, and decadal scales. At this site, long-term April 1 snow pack depth averages 1344 mm (1928-2011) with a CV of 48%. Snow fences increased equilibrium drift snow depth by 200%. Soil moisture pulses were shorter in duration and lower in magnitude in low- than medium- or high-snowfall years. Evapotranspiration (ET) in this arid location accounted for about 37 mol m-2 d-1 of water loss from the snow pack between January 1 and May 1; sublimation was 10% of ET for the same period. Despite considerable interannual variation in snow depth and total precipitation, plant water potential stayed relatively constant over eight consecutive years, but photosynthesis was highly variable. Over the long-term, changes in snow depth and melt timing have impacted growth of only three plant species. Moreover, annual growth ring increments of the conifers Pinus jeffreyi and Pi. contorta were not equally sensitive to snow depth. Results indicate complex interactions between snow depth, soil water, and plant characteristics at multiple temporal scales, which help drive the resilience of plant processes to large interannual variations in snow depth as well as manipulated snow depth. This resilience suggests that this ecotone may be stable in the face of anticipated changes in snow depth.

Loik, M. E.

2012-12-01

165

Strong Fluctuation Theory for Scattering, Attenuation, and Transmission of Microwaves through Snowfall  

Microsoft Academic Search

The strong fluctuation theory is applied to the study of the atmospheric snowfall which is modeled as a layer of random discretescatterers edium. As functions of size distribution, fractional volume, and radius of scatterers, we illustrate the relationship between the reflectivity factor and precipitation rate, the attenuation of the centimeter and millimeter waves, and the line-of-sight transmission of coherent and

Ya-Qiu Jin; Jin Au Kong

1985-01-01

166

A new snowfall detection algorithm over land using measurements from the Advanced Microwave Sounding Unit (AMSU)  

Microsoft Academic Search

This study introduces a new snowfall detection algorithm over land using AMSU measurements. The algorithm utilizes a combination of channels in the microwave window, water vapor and oxygen absorption regions. The new algorithm is combined with the current NOAA operational AMSU rain rate product for falling snow and rain areal extent retrievals over the U.S. These retrievals are compared with

Cezar Kongoli; Paul Pellegrino; Ralph R. Ferraro; Norman C. Grody; Huan Meng

2003-01-01

167

Range errors in global positioning system during ice cloud and snowfall periods  

Microsoft Academic Search

Results from a global positioning system (GPS) measurement campaign conducted during March 1989 on a baseline of 13.1415 km length show a relatively large discrepancy in the adjusted baseline height component during ice cloud and snowfall periods. These experimental observations have stimulated the development of a propagation-prediction model to investigate the performance of GPS carrier beat phase measurements during ice

J. M. Tranquilla; H. M. Al-Rizzo

1994-01-01

168

SeaWiFS: Snowfall in the mid-Atlantic States  

NASA Technical Reports Server (NTRS)

Snowfall from the January 3, 2002 storm in the mid-Atlantic states is clearly evident in this SeaWiFS image collected on January 4, 2002. The snow covered area stretches from central eastern Alabama to southern Delaware. Credit: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

2002-01-01

169

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

USGS Publications Warehouse

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

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

2001-01-01

170

Nuclear Winter.  

ERIC Educational Resources Information Center

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

Ehrlich, Anne

1984-01-01

171

Winter Weather  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Weather affects our everyday lives. Some days it's sunny and some days its not. The years weather is split up into seasons. 1. What are the four seasons? 2. What kind of weather do you see in the summer? 3. What kind of weather is unique to winter? 4. ...

Mrs. Bellows

2009-09-28

172

Measuring Snowfall at Summit, Greenland Using a Bistatic X-Band Radar  

NASA Astrophysics Data System (ADS)

With the current warming trend of the Earth's climate, the Greenland Ice Sheet (GIS) has been melting on its fringes and experiencing mass loss. However, the mass balance of the GIS as a whole is not well understood due to a deficiency of knowledge of the interior. Central to understanding this mass balance is precipitation, of which non-satellite derived observations over the central GIS are sparse. Here a conditional snowfall retrieval for the ground-based Precipitation Occurrence Sensor System (POSS), which is part of the Integrated Characterization of Energy, Clouds, Atmospheric state and Precipitation at Summit (ICECAPS) project in Greenland, is described. The conditional restraints for the POSS retrieval are based on qualitative ice particle habit information derived from relating periodic on-site ice crystal images to ranges of cloud base temperature derived from instantaneous lidar and interpolated radiosonde measurements. The snowfall from this habit-dependent retrieval is compared to various fixed-habit retrievals for the POSS, as well as other coinciding snowfall measurements taken at Summit by a vertical-pointing Ka-band cloud radar. Providing a broader perspective, this radar-based precipitation data is analyzed alongside weekly measurements from an accumulation forest, that includes a 10x10 grid of bamboo stakes that are used to measure the height change in the snow surface. In addition to snowfall, surface height changes include contributions from deposition, sublimation, melting, drifting, and compaction that must be accounted for. Using these three perspectives on snowfall, the annual cycle of precipitation at Summit, Greenland over the past three years is examined.

Castellani, B.; Shupe, M.

2013-12-01

173

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

USGS Publications Warehouse

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.

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

2014-01-01

174

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

PubMed

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 49years. 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 230mg/L by an average of more than 100 individual days per year during 2006-2011. The rapid rate of chloride concentration increase in these streams is likely due to a combination of possible increased road salt application rates, increased baseline concentrations, and greater snowfall in the Midwestern U.S. during the latter portion of the study period. PMID:25514764

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

2015-03-01

175

Single-dose cholecalciferol suppresses the winter increase in parathyroid hormone concentrations in healthy older men and women: a randomized triaI?3  

Microsoft Academic Search

A randomized double-blind controlled trial of a single oral dose of 2.5 mg(100 000 IU) cholecalciferol (vitamin D3) was conducted in the winter in 189 healthy free-living men and women aged 63-76 y. The mean baseline serum concentra- tion for 25-hydroxyvitamin D was 34.5 nmolfL and for parathy- roid hormone 3.18 pmolIL. After 5 wk, mean serum 25-hydroxy- vitamin D

Kay-Tee Khaw; Robert Scragg; Sean Murphy

176

Winter Workshop.  

ERIC Educational Resources Information Center

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…

Council of Outdoor Educators of Quebec, Montreal.

177

Winter Math  

NSDL National Science Digital Library

This article by Wendy Petti presents ideas and math activities for students to explore snowflakes and winter by making estimates, by counting and by measuring. Data collection, displays and analysis ideas are also included. A list of online resources with their links provides more wintry ideas for the classroom.

Petti, Wendy

2009-01-13

178

Winter Depression  

NSDL National Science Digital Library

A U.K. psychologist has developed a complex mathematical formula using seven variables to predict winter's emotional low point. The good news is the worst day of the year was last week; nonetheless, seasonal depression remains a problem for many. The first link (1) is to an article about the equation worked out by Dr. Cliff Arnall, who specializes in seasonal disorders at the University of Cardiff, Wales. The second link is to a WebMD page (2) about winter depression, often referred to as Seasonal Affective Disorder (SAD). The next link (3) is to a recent news story about the results of a five-year study that found, rather than antidepressant drug therapy or air ionizers, light box therapy is the best remedy for the seasonal condition. The fourth link is to a set of Frequently Asked Questions (4) about SAD offered by Columbia Presbyterian Medical Center in New York City. The fifth link, to the Winter Depression Research Group at the University of Tromso in Norway(5), explains why Norway is a natural SAD research laboratory. The next link is to a international portal site (6) maintained by medical professionals and researchers in the field of light therapy and biological rhythms. The final webpage(7), from Psychology Today, compares the symptoms of winter depression with summer depression.

179

Winter Hydrographer  

USGS Multimedia Gallery

Robert Bradley, a hydrologic technician with the Massachusetts USGS Office, headed to Maine to experience a winter ice measurement trip with Laura Flight, a hydrologic technician from the Maine USGS Office. Robert, originally from Florida, went to Aroostook County with Laura and got smacked in the f...

180

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

181

Strong fluctuation theory for scattering, attenuation, and transmission of microwaves through snowfall  

NASA Technical Reports Server (NTRS)

The strong fluctuation theory is applied to the study of the atmospheric snowfall which is modeled as a layer of random discrete-scatterers medium. As functions of size distribution, fractional volume, and radius of scatterers, the relationship is illustrated between the reflectivity factor and precipitation rate, the attenuation of the centimeter and millimeter waves, and the line-of-sight transmission of coherent and incoherent wave components. The theoretical results are shown to match favorably with experimental data.

Jin, Y.-Q.; Kong, J. A.

1985-01-01

182

A Physical Model to Determine Snowfall over Land by Microwave Radiometry  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

183

Characterization of video disdrometer uncertainties and impacts on estimates of snowfall rate and radar reflectivity  

NASA Astrophysics Data System (ADS)

Estimates of snow microphysical properties obtained by analyzing collections of individual particles are often limited to short timescales and coarse time resolution. Retrievals using disdrometer observations coincident with bulk measurements such as radar reflectivity and snowfall amounts may overcome these limitations; however, retrieval techniques using such observations require uncertainty estimates not only for the bulk measurements themselves, but also for the simulated measurements modeled from the disdrometer observations. Disdrometer uncertainties arise due to sampling and analytic errors and to the discrete, potentially truncated form of the reported size distributions. Imaging disdrometers such as the Snowflake Video Imager and 2-D Video Disdrometer provide remarkably detailed representations of snow particles, but view limited projections of their three-dimensional shapes. Particle sizes determined by such instruments underestimate the true dimensions of the particles in a way that depends, in the mean, on particle shape, also contributing to uncertainties. An uncertainty model that accounts for these uncertainties is developed and used to establish their contributions to simulated radar reflectivity and snowfall rate. Viewing geometry effects are characterized by a parameter, ϕ, that relates disdrometer-observed particle size to the true maximum dimension of the particle. Values and uncertainties for ϕ are estimated using idealized ellipsoidal snow particles. The model is applied to observations from seven snow events from the Canadian CloudSat/CALIPSO Validation Project (C3VP), a mid-latitude cold-season cloud and precipitation field experiment. Typical total uncertainties are 4 dB for reflectivity and 40-60% for snowfall rate, are highly correlated, and are substantial compared to expected uncertainties for radar and precipitation gauge observations. The dominant sources of errors are viewing geometry effects and the discrete, truncated form of the size distributions. While modeled Ze-S relationships are strongly affected by assumptions about snow particle mass properties, such relationships are only modestly sensitive to ϕ owing to partially compensating effects on both the reflectivity and snowfall rate.

Wood, N. B.; L'Ecuyer, T. S.; Bliven, F. L.; Stephens, G. L.

2013-12-01

184

Characterization of disdrometer uncertainties and impacts on estimates of snowfall rate and radar reflectivity  

NASA Astrophysics Data System (ADS)

Estimates of snow microphysical properties obtained by analyzing collections of individual particles are often limited to short time scales and coarse time resolution. Retrievals using disdrometer observations coincident with bulk measurements such as radar reflectivity and snowfall amounts may overcome these limitations; however, retrieval techniques using such observations require uncertainty estimates not only for the bulk measurements themselves, but also for the simulated measurements modeled from the disdrometer observations. Disdrometer uncertainties arise due to sampling and analytic errors and to the discrete, potentially truncated form of the reported size distributions. Imaging disdrometers such as the Snowflake Video Imager and 2-D Video Disdrometer provide remarkably detailed representations of snow particles, but view limited projections of their three-dimensional shapes. Particle sizes determined by such instruments underestimate the true dimensions of the particles in a way that depends, in the mean, on particle shape, also contributing to uncertainties. An uncertainty model that accounts for these uncertainties is developed and used to establish their contributions to simulated radar reflectivity and snowfall rate. Viewing geometry effects are characterized by a parameter, ?, that relates disdrometer-observed particle size to the true maximum dimension of the particle. Values and uncertainties for ? are estimated using idealized ellipsoidal snow particles. The model is applied to observations from seven snow events from the Canadian CloudSat CALIPSO Validation Project (C3VP), a mid-latitude cold season cloud and precipitation field experiment. Typical total uncertainties are 4 dBZ for reflectivity and 40-60% for snowfall rate, are highly correlated, and are substantial compared to expected observational uncertainties. The dominant sources of errors are viewing geometry effects and the discrete, truncated form of the size distributions. While modeled Ze-S relationships are strongly affected by assumptions about snow particle mass properties, such relationships are only modestly sensitive to ? owing to partially compensating effects on both the reflectivity and snowfall rate.

Wood, N. B.; L'Ecuyer, T. S.; Bliven, F. L.; Stephens, G. L.

2013-07-01

185

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

NASA Technical Reports Server (NTRS)

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 matching technique. All of these Z(sub e)-R relationships fall in the range of previously established Z(sub e)-R relationships for snowfall. This suggests that the current physical model developed in this study can reliably estimate the snowfall rate over land using the AMSU-B measured brightness temperatures.

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

2008-01-01

186

Winter Storm  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? ...

Smith, Miss

2010-09-27

187

Winter Storm  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the ...

Schilling, Ashley

2010-05-26

188

Winter Storms  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

Sappa, Mr.

2010-05-26

189

Winter snow  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. 1. What do you already know about the weather? 2. How does the weather effect you daily? Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What ...

Peterson, Lori

2009-09-28

190

Observed changes in extreme winter events in Europe with implication for transport system  

NASA Astrophysics Data System (ADS)

Extreme weather events, such as heavy rain and snow events, storms, strong winds, low visibility, hail and extreme temperatures can have negative impact on transport sector, causing severe damages and large economic losses. Weather and climate extremes have been changed over the last few decades and are likely to continue to change in the future due to the projected climate change. Consequences of changes may be both negative and positive for transportation. Extreme winter conditions have implications for the mobility and safety of operations, leading to significant transport disruptions, increased accident risk and costs of damage. In the present study we provide a comprehensive climatology of extreme winter weather events over the European continent relevant to the transport system with primary focus on recent decades (1971-2000). Individual phenomena, such as heavy snowfall, freezing temperatures, strong winds and wind gust and also their combinations, blizzard, freezing rain are considered. The estimation of the recent and past severe events is based on the observed data available from the meteorological services, from the E-OBS dataset and the ERA40 re-analysis dataset. The analysis of the relevant hazardous weather phenomena takes into account the ranking and impact threshold values defined from the viewpoint of different transport modes, such as road, rail, aviation, waterways and light, and infrastructure. A range of statistical methods are applied to define the features of these extremes, such as their probability, changes in the spatial extension, intensity and temporal duration. In order to assess the changes in regional extremes and their effects, a European regionalization regarding similar impacts on transport network is performed. The results of extreme weather and climate events classification are also shown through a set of geographical maps.

Vajda, A.; Tuomenvirta, H.

2010-09-01

191

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

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

192

Range Statistics and Suppressing Snowflakes Detects for Laser Range Finders in Snowfall  

Microsoft Academic Search

\\u000a This paper presents statistics on registrations from laser range finders in snowfall. The sensors are standard laser range\\u000a finders in robotics, the LMS200 and the URG-04LX. Three different working cases were identified for the pulsed laser range\\u000a finder.\\u000a \\u000a \\u000a 1) Normal operation with background objects present within the range of the sensor.\\u000a \\u000a \\u000a 2) Close range objects where ranges to objects are

Sven Rönnbäck; Åke Wernersson

193

Increases in platelet and red cell counts, blood viscosity, and arterial pressure during mild surface cooling: factors in mortality from coronary and cerebral thrombosis in winter  

Microsoft Academic Search

Six hours of mild surface cooling in moving air at 24 degrees C with little fall in core temperature (0.4 degree C) increased the packed cell volume by 7% and increased the platelet count and usually the mean platelet volume to produce a 15% increase in the fraction of plasma volume occupied by platelets. Little of these increases occurred in

W R Keatinge; S R Coleshaw; F Cotter; M Mattock; M Murphy; R Chelliah

1984-01-01

194

Characteristics of Snowfall over the Eastern Half of the United States and Relationships with Principal Modes of Low-Frequency Atmospheric Variability  

Microsoft Academic Search

Monthly data from 206 stations for the period 1947-93 are used to examine characteristics of snowfall over the eastern half of the United States and relationships with precipitation and the maximum temperature on precipitation days. Linkages between snowfall and modes of low-frequency circulation variability are diagnosed through composite analyses, based on results from a rotated Principal Component Analysis (PCA) of

Mark C. Serreze; Martyn P. Clark; David L. McGinnis; David A. Robinson

1998-01-01

195

Remote Measurements of Snowfalls in Wakasa Bay, Japan with Airborne Millimeter- wave Imaging Radiometer and Cloud Radar  

NASA Technical Reports Server (NTRS)

In this paper we explore the application of combined millimeter-wave radar and radiometry to remotely measure snowfall. During January-February of 2003, a field campaign was conducted with the NASA P-3 aircraft in Wakasa Bay, Japan for the validation of the AMSRE microwave radiometer on board the Aqua satellite. Among the suite of instruments-on board the P-3 aircraft were the Millimeter-wave Imaging Radiometer (MIR) from the NASA Goddard Space Flight Center and the 94 GHz Airborne Cloud Radar (ACR) which is co-owned and operated by NASA Jet Propulsion Laboratory/University of Massachusetts. MIR is a total power, across-track scanning radiometer that measures radiation at the frequencies of 89, 150, 183.3 +/- 1, 183.3 +/- 3, 183.3 +/-7, 220, and 340 GHz. The MIR has flown many successful missions since its completion in May 1992. ACR is a newer instrument and flew only a few times prior to the Wakasa Bay deployment. These two instruments which are particularly well suited for the detection of snowfall functioned normally during flights over snowfall and excellent data sets were acquired. On January 14, 28, and 29 flights were conducted over snowfall events. The MIR and ACR detected strong signals during periods of snowfall over ocean and land. Results from the analysis of these concurrent data sets show that (1) the scattering of millimeter-wave radiation as detected by the MIR is strongly correlated with ACR radar reflectivity profiles, and (2) the scattering is highly frequency-dependent, the higher the frequency the stronger the scattering. Additionally, the more transparent channels of the MIR (e.g., 89, 150, and 220 GHz) are found to display ambiguous signatures of snowfall because of their exposure to surface features. Thus, the snowfall detection and retrievals of snowfall parameters, such as the ice water path (IWP) and median mass diameter (D(me)) are best conducted at the more opaque channels near 183.3 GHz and 340 GHz. Retrievals of IWP and D(me) using the MIR measurements at 183.3 and 340 GHZ are currently in progress, and the results will be compared with those derived from the ACR reflectivity profiles. Implication from this comparison will be discussed.

Wang, J. R.; Austin, R.; Liu, G. S.; Racette, P. E.

2004-01-01

196

Numerical diagnosis of a heavy snowfall event in the center of the Iberian Peninsula  

NASA Astrophysics Data System (ADS)

On 4 March 2011, an exceptionally heavy snowfall event affected the Madrid region on the central Iberian Peninsula. At altitudes of 1200 m, snowfall reached a record of 34 cm in 24 h and produced considerable damage and disruption to electricity distribution and transport systems. Maximum intensity precipitation was identified between 1600 and 1800 UTC. Associated precipitation was particularly intense in the Guadarrama Mountains (at the center of the Peninsula, near Madrid). Analysis of Meteosat Second Generation (MSG) satellite images revealed a dark area, generated by a stratospheric intrusion originating in the Atlantic and reaching the Iberian Peninsula. We studied synoptic conditions and mesoscale factors involved in the event, using the Weather Research and Forecasting (WRF) model. This permitted analysis of the evolution of the dry intrusion caused by a tropopause fold, its movement, and frontogenesis-related mechanisms during its crossing of the Guadarrama Mountains. The blocking of a wet warm mass at altitude owing to a descent of the tropopause but mainly at low levels because of orographic effects, helped concentrate moisture and generate potential instability (PI). This was subsequently released in deep convection, owing to the formation of frontogenesis.

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

2015-02-01

197

Can we estimate precipitation rate during snowfall using a scanning terrestrial LiDAR?  

NASA Astrophysics Data System (ADS)

Accurate snowfall measurements in windy areas have proven difficult. To examine a new approach, we have installed an automatic scanning terrestrial LiDAR at Mammoth Mountain, CA. With this LiDAR, we have demonstrated effective snow depth mapping over a small study area of several hundred m2. The LiDAR also produces dense point clouds by detecting falling and blowing hydrometeors during storms. Daily counts of airborne detections from the LiDAR show excellent agreement with automated and manual snow water equivalent measurements, suggesting that LiDAR observations have the potential to directly estimate precipitation rate. Thus, we suggest LiDAR scanners offer advantages over precipitation radars, which could lead to more accurate precipitation rate estimates. For instance, uncertainties in mass-diameter and mass-fall speed relationships used in precipitation radar, combined with low reflectivity of snow in the microwave spectrum, produce errors of up to 3X in snowfall rates measured by radar. Since snow has more backscatter in the near-infrared wavelengths used by LiDAR compared to the wavelengths used by radar, and the LiDAR detects individual hydrometeors, our approach has more potential for directly estimating precipitation rate. A key uncertainty is hydrometeor mass. At our study site, we have also installed a Multi Angle Snowflake Camera (MASC) to measure size, fallspeed, and mass of individual hydrometeors. By combining simultaneous MASC and LiDAR measurements, we can estimate precipitation density and rate.

LeWinter, A. L.; Bair, E. H.; Davis, R. E.; Finnegan, D. C.; Gutmann, E. D.; Dozier, J.

2012-12-01

198

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

199

Microwave Remote Sensing of Lake-Induced Snowfall: Observation, Modeling, and Cloud Microphysical Implications  

NASA Astrophysics Data System (ADS)

Combined passive and active microwave remote sensing instruments are utilized to study lake-induced snowfall at mid- to high-latitudes. Our research efforts will concentrate on the Baltic Sea region of northern Europe due to the availability of ground-based radar data that complement passive microwave data obtained from satellites. Observations using the Advanced Microwave Scanning Radiometer -" Earth Observing System (AMSR-E) indicate that banded, mesoscale lake effect snowfall structures can be resolved with current passive microwave platforms. When confined to over-water observations, emission from supercooled cloud liquid water in the lower atmosphere produces an elevated brightness temperature signature, as well as noticeable depolarization effects, in various AMSR-E frequencies. In addition to successfully identifying these snow events using satellite data, we will also study whether lake-induced snow produces a consistently measurable microwave scattering signature due to frozen hydrometeors within the snowbands. Using radiative transfer modeling that is built upon a physically-based framework, we will assess cloud microphysical features that affect the proper detection and modeling of lake effect snow, as well as discuss the correction of biases that arise using our modeling methodology.

Kulie, M. S.; Bennartz, R.

2006-05-01

200

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

NASA Astrophysics Data System (ADS)

Recent seismological observations of phases reflecting (PKiKP), diffracting (PKPdiff), or going through the inner core (PKIKP) called for modification of PREM at the top of the Inner Core Boundary (ICB). Both the AK135 and PREM2 models proposed a flattened P-wave velocity gradient relative to PREM in the ~200 km region above the ICB, often referred to as the F-layer. This reduced velocity gradient implies density stratification, which may reflect a gradient in the light element concentration decreasing from the top of the F-layer to the ICB. Here we propose a mechanism to generate a chemical stratification in the F-layer through crystallization of solid iron “snow” at the top of the F-layer, which then precipitates, partially dissolves, and eventually accumulates at the ICB to produce the F-layer and contribute to the growth of the inner core. The formation of iron “snow” in the outer core (OC) requires that the core geotherm intercepts the FeX liquidus, where X is an alloying light element, to create a region of stability for solid iron at the base of the OC. This study examines two potential scenarios in which iron “snowfall” might occur in the F-layer. The first scenario involves the FeX liquidus gradient decreasing or even changing sign such that a region of solid stability is created at the top of the F-layer. This behavior is observed in the Fe-S binary system at lower pressures and has been proposed to cause “snowing” in the interiors of Mercury and Ganymede. In the second case, the outer core temperature may increase relative to the FeX liquidus near the ICB due to viscomagnetic heating. Results based on mineral physics calculations of an iron-sulfur binary system show that an F-layer composition ranging from 7.2 wt% S at the top of the F-layer to 5.7 wt% S at the ICB is sufficient to explain the Vp structure of the F-layer in AK135. In these calculations, the density and bulk modulus as a function of depth were determined using the 3rd order Birch-Murnaghan equation of state. Temperature was accounted for using the Mie-Grüneisen-Debye equation of state. Published experimental values for Fe-FeS solid and liquid end-members were used and those of intermediate compositions were determined using ideal solution theory. The crystal fraction was assumed to be small enough to allow approximation of a pure liquid composition in the F-layer. Comparison of our F-layer model to PREM results in a better fit to the observed travel time data. Comparison of normal mode eigenfrequencies from the two models shows subtle differences; therefore normal modes have been determined to be insensitive to the small-scale structure of the relatively thin F-layer

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

2010-12-01

201

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

NASA Astrophysics Data System (ADS)

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

Changnon, Stanley A.; Changnon, David

2005-09-01

202

Winter Cover Crop and Subsurface Hydrology  

Microsoft Academic Search

Winter cover crop increases infiltration of rainfall, reduces runoff which eventually increases the soil water content of the root zone. On the other hand, it depletes soil moisture through evapotranspiration. However, little information is available on the potential influence of winter cover crop on soil water storage. The change of soil water storage is investigated in a field experiment with

M. Islam; W. W. Wallender; S. Wicks; R. Howitt; J. P. Mitchell

2002-01-01

203

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

NASA Astrophysics Data System (ADS)

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

Notaro, Michael

204

Characteristics of large snowfall events in the montane western United States as examined using snowpack telemetry (SNOTEL) data  

Microsoft Academic Search

Daily snow water equivalent records from the snowpack telemetry archive are used to assess spatiotemporal characteristics of large snowfall events over the montane western United States. The largest mean annual (leading) events are found in the Pacific Northwest and Sierra Nevada. The mean leading event lasting up to 72 hours typically accounts for 10-23% of the water equivalent of annual

Mark C. Serreze; Martyn P. Clark; Allan Frei

2001-01-01

205

Ross River virus infection surveillance in the Greater Perth Metropolitan area--has there been an increase in cases in the winter months?  

PubMed

An increase in off-season (June to September) Ross River virus (RRV) notifications from the greater Perth metropolitan area was observed from 2006 to 2009. We investigated the increase to determine whether it is likely to have reflected a true increase in off-season cases. A single positive RRV IgM test result is sufficient for RRV notification but where follow-up testing was performed, the positive predictive value of an IgM test where IgG was negative was very low in the off-season and also in the season when using the only commercially available test kit. The increase in off-season notifications was not associated with an increase in off-season testing. Some Perth laboratories use more stringent notification criteria than the nationally agreed RRV case definition, and the geographical distribution of samples tested varies between laboratories. Our findings make a strong case to change the nationally agreed case definition for RRV to not accept a single IgM positive test result as laboratory definitive evidence where the IgG is negative. Our study also identified a range of challenges in interpreting changes in seasonal patterns and geographical distribution of RRV. Any such observed changes should be investigated through further data analysis and/or mosquito trapping and testing in order to assess validity. PMID:25222206

Selvey, Linda A; Donnelly, Jenny A; Lindsay, Michael D; PottumarthyBoddu, Sudha; D'Abrera, Victoria C; Smith, David W

2014-06-01

206

Radar observation of snowfall from a natural-draft cooling tower plume  

SciTech Connect

One of the potential atmospheric effects of energy dissipation at large power parks is the mesoscale modification of the precipitation field. Meteorological conditions favorable for such an influence mainly correspond to naturally precipitating atmospheres and make the identification of the anthropogenic components difficult. In this paper, millimetric Doppler radar data are used in order to analyze the three-dimensional structure of snowfalls associated, in a perturbed environment, with a natural-draft cooling tower park. The plumes observed spread out in the atmospheric boundary layer with spread angles of 15/sup 0/--30/sup 0/ over a distance of more than 20 km. Their main characteristics compare favorably with Koenig's numerical simulation results.

Sauvageot, H.

1987-11-01

207

Observed snowfall and river discharge trend and low-frequency variability over Alps  

NASA Astrophysics Data System (ADS)

We present a twofold analysis of long-term trend and variability of different factors affecting the hydrological cycle over the Alps in spring. The study is based on datasets derived from observations for the last 150 years. In one case we focus on snowfall flux, which we found shifting between two different regimes in concert with the Atlantic Multidecadal Oscillation. This teleconnection is explained by a mixture of changes in circulation and by local climatic feedbacks. Moreover, we analyzed the timing of the river discharge peaks relative to the main Alpine rivers, finding similar features of low frequency variability, and a common anticipation tendency of more than two weeks per century, probably explained by a change of seasonality of total precipitation.

Zampieri, Matteo; Scoccimarro, Enrico; Gualdi, Silvio

2014-05-01

208

Evidence of nonspheroidal behavior in millimeter-wavelength radar observations of snowfall  

NASA Astrophysics Data System (ADS)

Recent modeling results have indicated that, in general, idealized homogeneous spheroidal models of ice crystals and snowflakes cannot consistently describe radar backscattering from snowfall when the radar wavelengths are on the order of the snowflake size. In this paper, we provide empirical evidence supporting this prediction by analyzing collocated airborne radar measurements at 13.4 GHz, 35.6 GHz and 94 GHz. The analysis is performed by applying a recently developed method making use of two simultaneously measured dual-frequency ratios, allowing one to distinguish between the multifrequency backscattering behavior of detailed aggregate snow models and that of homogeneous spheroids. We demonstrate that in some naturally occurring cases, detailed snowflake models, which account for their complex structure, are required to describe backscattering by these particles in a manner that is consistent over multiple wavelengths. This implies that the spheroidal approximation is not always adequate as a snowflake shape model in radar retrievals at this wavelength range.

Leinonen, J.; Kneifel, S.; Moisseev, D.; Tyynelä, J.; Tanelli, S.; Nousiainen, T.

2012-09-01

209

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

SciTech Connect

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

Chatelain, E.E. [Valdosta State Univ., GA (United States)

1996-09-01

210

Nutrition Frontiers - Winter 2010  

Cancer.gov

Nutrition Frontiers - Winter 2010 Winter 2010 Volume 1, Issue 1 Dear Colleague, Welcome to the first issue of Nutrition Frontiers, a quarterly newsletter from the Nutritional Science Research Group (NSRG), Division of Cancer Prevention, NCI. In this

211

A physical model to estimate snowfall over land using microwave measurements  

NASA Astrophysics Data System (ADS)

Falling snow is an important component of global precipitation in extratropical regions. This study describes the methodology and results of physically based retrievals of snow falling over land surfaces. Because microwave emitted by snow-covered surfaces are highly variable, precipitating snow above such surfaces is difficult to observe using window channels that occur at low frequencies (nu < 100 GHz). Furthermore, at frequencies nu < 37 GHz, sensitivity to liquid hydrometeors is dominant. These problems are mitigated at high frequencies (nu > 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 and supercooled water in the upper atmosphere. The Discrete Dipole Approximation (DDA) method was employed to generate the single scattering parameters for nonspherical snow crystals. Comparisons show that neither equivalent spheres nor dielectric mixing theories could account for all measurements. Therefore, this study builds a look up table of the DDA calculated single scattering parameters and employs it in calculations directly. Comparisons show that DDA results calculated in this study were compatible with radar and radiometer measurements for the limited number of examples. The retrieval algorithm relied on a multi-parameter cloud model to generate the vertical structure of a snow cloud, including snow water content, snow particle effective diameter, supercooled water, and water vapor. A MM5 cloud simulation was used to provide useful statistics for generating those cloud characteristics. The snow cloud profiles and surface emissivities were then used in radiative transfer calculations that were optimized against AMSU-B observations at 89, 150, and 183.3 +/- 7, +/- 3, and +/- 1 GHz. Four variables used to adjust the snow water content, relative humidity, cloud liquid water content, and surface emissivity were sufficient to estimate snowfall rates consistent with NWS radar reflectivity measurements during the New England blizzard on March 5, 2001 and to yield a Ze-M relationship that was consistent with others reported in the literature.

Kim, Min-Jeong

212

Winter precipitation mesoscale variability and its impact on SO{sub 2} deposition characteristics  

SciTech Connect

Wet deposition of the atmospheric pollutants in the middle-latitudes is known to occur mainly in the frontal precipitation zones. Since the latter are spatially and temporally inhomogeneous, the spot-like patterns of the pollutant fallouts are common. Thus, knowledge of frontal precipitation mesoscale structure is important for a correct description of the acid deposition patterns. This paper is based on digital radar observations of winter-time frontal precipitation features in 30 frontal zones in the Central European Russia. The observed features were mainly bands and cells. Quantitative characteristics of mesoscale snow intensity variability are given. The major contribution into precipitation amounts are made by intensities of 0.1-0.2 mm/h and 0.5-1.0 mm/h. Other precipitation intensities are less frequent and effective. The relative contributions of different snowfall intensities into total amount of snowfall depend on the type of front and related cyclone trajectory. Based on known theoretical and empirical relations, the data on precipitation variability have been used to assess the spatial inhomogeneity of SO{sub 2} scavenging coefficients and wet deposition rates for typical winter-time frontal situations and SO{sub 2} concentration in the Central European Russia.

Bezukova, N.A.; Postnov, A.A.; Khalili, M.F. [Dolgoprudny, Moscow (Russian Federation)

1996-12-31

213

Rainfall and Snowfall Observations by the Airborne Dual-frequency Precipitation Radar during the Wakasa Bay Experiment  

NASA Technical Reports Server (NTRS)

Radar data obtained through the NASA/JPL Airborne Precipitation Radar APR-2 during the Wakasa Bay Experiment in January/February 2003 were processed to obtain calibrated reflectivity measurements, rainfall/snowfall velocity measurements, classification of the surface type and detection of the boundaries of the melting layer of precipitation. In this paper the processing approach is described together with an overview of the resulting data quality and known issues.

Tanelli, Simone; Im, Eastwood; Durden, Stephen L.; Meagher, Jonathan P.

2004-01-01

214

Selection through predation, snowfall and microclimate on nest-site preferences in the Water Pipit Anthus spinoletta  

Microsoft Academic Search

Nest-site characteristics can have a strong impact on reproductive success in birds. Nest sites should simultaneously protect from predators, offer shelter and provide a favourable micro- climate. We studied the relationship between three agents of natural selection (predators (i.e. Adders and birds\\/mammals), snowfall and microclimate), nest-site characteristics and reproductive success to determine whether these influenced preference for specific nest-site characteristics

Claudia M. Rauter; Heinz-Ulrich Reyer; Kurt Bollmann

2002-01-01

215

Air Parcel Trajectories and Snowfall Related to Five Deep Drilling Locations in Antarctica Based on the ERA15 Dataset  

Microsoft Academic Search

Five-day backward air parcel trajectories are used to define potential moisture sources of snow falling at five Antarctic deep drilling locations: Byrd, DML05, Dome C, Dome F, and Vostok. The trajectory calculations are based on European Centre for Medium-Range Weather Forecasts reanalysis data, ERA-15 (1979-93). Based on model precipitation, a distinction is made between cases with and without snowfall at

C. H. Reijmer; M. R. van den Broeke; M. P. Scheele

2002-01-01

216

[Chemical characteristics and insoluble particulates' surface morphology of a snowfall process in the southeastern suburb of Urumqi].  

PubMed

In order to understand the composition and potential pollution of metal elements in precipitation in the southeastern suburb of Urumqi on February 21 to 23, 2012, soluble elements were determined by inductively coupled plasma mass spectrometry (ICP-MS); in addition, energy spectrum and morphological analysis were made for insoluble particulates. The results showed that the content of toxic heavy metals in snowfall was a little high; and the enrichment factors of Se, As and Cd were 124.65, 57.69 and 36.70, respectively, showing a typical coal pollution characteristic. The back trajectory cluster analysis suggested that the coal fly ash of snowfall mainly induced by air masses originated from the coal-fire power plant in the Southwestern sampling site. Morphology analyses conducted under an scan electron microscope demonstrated fly ash coming from coal burning process and irregular mineral are in the majority of insoluble particulates in snowfall, soot aggregates were compact, when the soot was wetted (the hygroscopic behaviour), and the morphology changed further. Insoluble particulates of the southeastern suburb of Urumqi were coal fly ash and insoluble soil minerals. PMID:24946568

Lu, Hui; Wei, Wen-Shou; Cui, Cai-Xia; He, Qing; Wang, Yao

2014-04-01

217

The role of snowfall in forming the seasonal ice caps of Mars: Models and constraints from the Mars Climate Sounder  

NASA Astrophysics Data System (ADS)

Wintertime observations of the martian polar regions by orbiting spacecraft have provided evidence for carbon dioxide clouds, which measurably alter the polar energy budget and the annual CO2 cycle. However, it has remained unclear whether snowfall contributes a substantial quantity to the accumulating seasonal ice caps. We develop models to constrain precipitation rates based on observations of south polar CO2 clouds by the Mars Climate Sounder (MCS), and show that snowfall contributes between 3% and 20% by mass to the seasonal deposits at latitudes 70-90°S. The lower bound on this estimate depends on a minimum effective cloud particle size of ?50 ?m, derived by comparing the short lifetimes (less than a few hours) of some clouds with calculated sedimentation velocities. Separate constraints from infrared spectra measured by MCS suggest CO2 cloud particles in the size range 10-100 ?m. Snow particles are not likely to re-sublime before reaching the surface, because the lower atmosphere in this region remains near saturation with respect to CO2. Based on cooling rate calculations, snowfall originating below 4 km altitude likely contributes a comparable or greater amount to the seasonal deposits than the rest of the atmosphere. Due to the positive feedback between cloud particle number density and radiative cooling, CO2 snow clouds should propagate until they become limited by the availability of condensation nuclei or CO2 gas. Over the south polar residual cap, where cloud activity is greatest, atmospheric radiative cooling rates are high enough to offset heat advected into the polar regions and maintain consistent snowfall. At latitudes of 60-80°S the lower atmosphere tends to be slightly sub-saturated and rapid cooling by mechanical lift driven by orography or convergent flow may be required to initiate a snowstorm, consistent with the more sporadic clouds observed by MCS in this region, and their correlation with topographic features. Snowfall and accumulation at the surface are found to be inevitable consequences of the polar energy budget, unless advection redistributes heat from lower latitudes in much greater quantities than expected.

Hayne, Paul O.; Paige, David A.; Heavens, Nicholas G.

2014-03-01

218

Winter and Summer Views of the Salt Lake Region  

NASA Technical Reports Server (NTRS)

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

2002-01-01

219

Variation in weight of migratory Dippers Cinclus cinclus in their Finnish winter quarters  

Microsoft Academic Search

Weight variation in the Dipper was studied during 9 winters in southwest Finland, where the species is a winter visitor. Males were heavier than females and adults heavier than first-year birds, while weight was independently correlated with wing length. Weights increased during the day, varied during the course of each winter, and differed between winters. The extra fat deposits apparently

E. Lehikoinen; J. Hakala

1988-01-01

220

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

NASA Astrophysics Data System (ADS)

In midwinter, heavy snowfall events are often brought in the Japan Sea side of the Japan Islands by the organized convective snowfall systems in the cold air outbreak situations. However, although the air temperature around the Japan Islands is still rather higher from November to early December ("early winter"), the "wintertime pressure pattern" often appears due to the considerable development of the Siberian high already in that season. Since the seasonal cycle in East Asia shows great variety with many rapid seasonal transitions influenced by the Asian monsoon system, detailed comparison of the daily precipitation climatology and the relating atmospheric processes in the cold air outbreak situations between early winter and midwinter would give us an interesting information for comprehending the overall aspects of such seasonal cycle there. Thus the present study firstly examined the daily precipitation climatology mainly at Takada, as an example for Hokuriku District, during the early to mid- winter of 1970/71 to 2009/10. Then the detailed analyses were made for the 1983/1984 winter (one of the coldest winters during that period) based on the operational meteorological data by JMA, including the ocean buoy data in the southern part of the Japan Sea for evaluating the sensible and the latent heat fluxes from the sea (referred to as SH and LH, respectively). The total precipitation at Takada in early winter was as large as in midwinter, although it was brought mainly not as snow but as rain. Such large climatological value was mainly reflected by the precipitation in the "wintertime pressure pattern" with large contribution of the days with more than 30 mm/day. Interestingly, mean daily precipitation in the "wintertime pressure pattern" in early winter was greater than in midwinter. It is noted that such features were generally found even in the latter half of the analysis period when the warmer winter years appeared more frequently than in the former half. According to the case study for 1983/84 winter, although the "wintertime pressure pattern" appeared rather frequently already from early November, each event of that pattern tended to persist only a several days. In addition, the organization of the shallow convective clouds in the cold air outbreak situation as often found in midwinter was not clearly observed. However, strong cold air advection in early winter as in midwinter over the warm underlying sea, at least in the mature stage of each "wintertime pressure situation", seems to enable the extremely huge amount of LH and the equivalently intense SH to that in midwinter, resulting in the large daily precipitation there through the enhancement of the air mass transformation process over the Japan Sea.

Kato, Kuranoshin; Nishimura, Nanako; Haga, Yuichi

2014-05-01

221

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

NASA Technical Reports Server (NTRS)

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

Molthan, Andrew L.

2010-01-01

222

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

NASA Technical Reports Server (NTRS)

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 characteristics. Each system provides a unique perspective. The WSR-88D operates in a surveillance mode, sampling cloud volumes of Rayleigh scatterers where reflectivity is proportional to the sixth moment of the size distribution of equivalent spheres. The CloudSat radar provides enhanced sensitivity to smaller cloud ice crystals aloft, as well as consistent vertical profiles along each orbit. However, CloudSat reflectivity signatures are complicated somewhat by resonant Mie scattering effects and significant attenuation in the presence of cloud or rain water. Here, both radar systems are applied to a case of light to moderate snowfall within the warm frontal zone of a cold season, synoptic scale storm. Radars allow for an evaluation of the accuracy of a single-moment scheme in replicating precipitation structures, based on the bulk statistical properties of precipitation as suggested by reflectivity signatures.

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

2009-01-01

223

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

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

224

Winter Weather Introduction  

E-print Network

Winter Weather Management #12;Introduction · Campus Facilities Staff · Other Campus Organizations #12;Purpose · Organize and coordinate the campus response to winter weather events to maintain campus for use by 7 AM. · Response will be modified depending upon forecast and current weather conditions. #12

Taylor, Jerry

225

Winter 2014 Economics 471  

E-print Network

Winter 2014 Economics 471: Public Finance Government Finance -- Syllabus Winter 2014 1 US Treasury intervention in the market. After covering basic prin- ciples of public finance, we will focus on the taxing Textbook: Public Finance and Public Policy (4th Edition) by Jonathan Gruber. Available at the bookstore

Carter, John

226

Winter and Specialty Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

The two main commercial types of wheat are durum (Triticum durum L., 2n=4x= 28) and common (T. aestivum L, 2n=6x=42.) wheat, the latter being the more widely grown. Wheat has three growth habits, namely winter (wheats grown over the winter months that require vernalization and can withstand prolong...

227

Winter Olympic Sports  

NSDL National Science Digital Library

Exploring Winter Olympic Sports Let's take a look at some of the different winter olympic sports Alpine Skiing Biathalon Bobsleigh Cross country Curling Figure Skating Freestyle skiing Ice Hockey Luge Nordic Combined Short track speed skating Skeleton Ski Jumping Snowboard Speed Skating ...

Keller, Mrs.

2010-01-23

228

Winter Art Education Project  

ERIC Educational Resources Information Center

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…

Jokela, Timo

2007-01-01

229

Winter Math Activities  

NSDL National Science Digital Library

This webpage of winter math activities includes seasonal activities for patterns, graphing, symmetry, estimations, and glyphs. Other resources on this page include literature connections, links to more winter resources, and pictures of student work. Activities are centered on penguins, snowflakes, snowman, and gingerbread.

Kawas, Terry

2013-01-01

230

Attribution of Autumn/Winter 2000 flood risk in England to anthropogenic climate change: A catchment-based study  

NASA Astrophysics Data System (ADS)

SummaryAlthough no single weather-related event can be directly attributed to climate change, new techniques make it possible to estimate how much the chance of an event has been altered by anthropogenic emissions. This paper looks at the floods that occurred in England in Autumn/Winter 2000, by using large ensembles of 1-year climate model simulations representing April 2000-March 2001. These represent an industrial climate and four estimates of an hypothetical non-industrial climate (without historical greenhouse gas emissions), and are used to drive hydrological models for eight catchments in England. The simulated flows are used to assess the impact of historical emissions on the chance of occurrence of extreme floods in each catchment, through calculation of the fraction of attributable risk ( FAR). Combining results for the four non-industrial climates, positive median values of FAR indicate that, for all but one catchment, emissions are likely to have led to an increased chance of flooding in the October-December period. Definitive conclusions are difficult however, as there are wide bands of uncertainty in FAR, with distributions generally spanning no attributable difference in risk ( FAR = 0). One catchment shows a decreased flood chance (negative median FAR), due to its high permeability, but an analysis of the effect of antecedent conditions shows that a longer period of climate data than 1 year is probably required to obtain more representative values of FAR for such catchments. The inclusion of snowfall/snowmelt is also shown to be important for floods over the October-March period, as the reduced likelihood of snowmelt-induced floods in the warmer temperatures of the industrial climate moderates the increased flood chance due to other sources of flooding.

Kay, A. L.; Crooks, S. M.; Pall, P.; Stone, D. A.

2011-08-01

231

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

NASA Astrophysics Data System (ADS)

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.

Yang, D.; Smith, C.

2013-12-01

232

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

SciTech Connect

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

Kim, J.; Miller, N.L.

1995-09-28

233

Carbon dioxide snow clouds on Mars: South polar winter observations by the Mars Climate Sounder  

NASA Astrophysics Data System (ADS)

We present south polar winter infrared observations from the Mars Climate Sounder (MCS) and test three hypotheses concerning the origins of “cold spots”: regions of anomalously low infrared brightness temperatures, which could be due to enrichment in non-condensable gases, low-emissivity surface frost, or optically thick CO2 clouds. Clouds and surface frosts have been historically difficult to distinguish, but the unique limb sounding capability of MCS reveals extensive tropospheric CO2 clouds over the cold spots. We find that both clouds and surface deposits play a significant role in lowering the infrared emissivity of the seasonal ice cap, and the granular surface deposits are likely emplaced by snowfall. Surface temperatures indicate the polar winter atmosphere is enriched by a factor ˜5-7 in non-condensable gases relative to the annual average, consistent with earlier gamma ray spectrometer observations, but not enough to account for the low brightness temperatures. A large ˜500-km diameter cloud with visible optical depth ˜0.1-1.0 persists throughout winter over the south polar residual cap (SPRC). At latitudes 70-80°S, clouds and low emission regions are smaller and shorter-lived, probably corresponding to large-grained “channel 1” clouds observed by the Mars Orbiter Laser Altimeter. Snowfall over the SPRC imparts the lowest emissivity in the south polar region, which paradoxically tends to reduce net accumulation of seasonal CO2 by backscattering infrared radiation. This could be compensated by the observed anomalously high summertime albedo of the SPRC, which may be related to small grains preserved in a rapidly formed snow deposit.

Hayne, Paul O.; Paige, David A.; Schofield, John T.; Kass, David M.; Kleinböhl, Armin; Heavens, Nicholas G.; McCleese, Daniel J.

2012-08-01

234

Winter refuge for Aedes aegypti and Ae. albopictus mosquitoes in Hanoi during Winter.  

PubMed

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

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

2014-01-01

235

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

PubMed Central

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

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

2014-01-01

236

Mountaintop and radar measurements of anthropogenic aerosol effects on snow growth and snowfall rate  

Microsoft Academic Search

A field campaign designed to investigate the second indirect aerosol effect (reduction of precipitation by anthropogenic aerosols which produce more numerous and smaller cloud droplets) was conducted during winter in the northern Rocky Mountains of Colorado. Combining remote sensing and in-situ mountain-top measurements it was possible to show higher concentrations of anthropogenic aerosols (?1 ?g m?3) altered the microphysics of

Randolph D. Borys; Douglas H. Lowenthal; Stephen A. Cohn; William O. J. Brown

2003-01-01

237

Important role for ocean warming and increased ice-shelf melt in Antarctic sea-ice expansion  

NASA Astrophysics Data System (ADS)

Changes in sea ice significantly modulate climate change because of its high reflective and strong insulating nature. In contrast to Arctic sea ice, sea ice surrounding Antarctica has expanded, with record extent in 2010. This ice expansion has previously been attributed to dynamical atmospheric changes that induce atmospheric cooling. Here we show that accelerated basal melting of Antarctic ice shelves is likely to have contributed significantly to sea-ice expansion. Specifically, we present observations indicating that melt water from Antarctica's ice shelves accumulates in a cool and fresh surface layer that shields the surface ocean from the warmer deeper waters that are melting the ice shelves. Simulating these processes in a coupled climate model we find that cool and fresh surface water from ice-shelf melt indeed leads to expanding sea ice in austral autumn and winter. This powerful negative feedback counteracts Southern Hemispheric atmospheric warming. Although changes in atmospheric dynamics most likely govern regional sea-ice trends, our analyses indicate that the overall sea-ice trend is dominated by increased ice-shelf melt. We suggest that cool sea surface temperatures around Antarctica could offset projected snowfall increases in Antarctica, with implications for estimates of future sea-level rise.

Bintanja, R.; Oldenborgh, G. V.; Drijhout, S.; Wouters, B.; Katsman, C. A.

2013-12-01

238

American woodcock winter distribution and fidelity to wintering areas  

USGS Publications Warehouse

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

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

1990-01-01

239

Winter 2007 Practicing Medicine  

E-print Network

of tennessee HealtH science center Medicine Magazine Winter 2007 CommunicationsTeam Writing,Editing Sh New Faces News Bites News · UTHSC Receives NIH Funding · UTMG to Grow under Dr. Schwab · Working

Cui, Yan

240

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

NASA Astrophysics Data System (ADS)

Snowpack is the most important water resource in the Western United States, and widely regarded as the most vulnerable. It is thus critical to provide water managers the most accurate estimate of how that resource will evolve as the climate changes, including its societal impact. The headwaters region of Colorado that includes, among others, the Colorado, Platte, Rio Grande and Arkansas Rivers, is one of the key source regions for water in the Southwest as ~85% of the streamflow for the Colorado River comes from snowmelt in this region. This region is a particularly difficult area for global climate models to properly handle, with inconsistent snowpack trends in this region from different models despite consistent predictions of temperature increases in this region from all climate models from both the 3rd and 4th IPCC reports (2001, 2007). Observations over the past 50 years in the upper Colorado River basin also reflect the same increasing temperature trend but show no identifiable trends in snowpack (Edwards and Redmond, 2005, Colorado and California Water Users Conference publication). A recent analysis of the 2007 IPCC 4th Assessment global models by Hoerling and Eischeid (2006,Southwest Hydrology) indicates that the combination of increased temperature and weak to no trends in snowfall will produce unprecedented drought conditions over the next 50 years in the Southwest due to a strong increase in evapotranspiration associated with the increased temperature. While the above predictions based on global models indicate dire consequences for the Southwest, it should also be noted that the AR4 indicates that global models typically perform poorly in mountainous regions due to the poor depiction of terrain as well as significant uncertainty in detailed hydrometeorological processes (i.e. cloud/precipitation microphysics, embedded convection and cloud-scale circulations, snowpack and snow ablation, and runoff generation in complex terrain) that currently limit model simulation skill. Colorado's headwaters region is dominated by high altitude snow melt, so climate assessments in this region using global models are particularly uncertain. However, simple increases in model resolution without clearer understanding and representation of hydroclimatic processes controlling water resources will not be sufficient for improving model performance. It is therefore critical to examine climate impacts in this region using detailed coupled atmosphere-hydrology models in order to more realistically simulate precipitation, sublimation, and runoff processes, as well as their impact on managed water systems. This paper will present results of annual snowfall, snow/rain fraction, and snowpack over Colorado based on high resolution simulations of the Weather Research and Forecast (WRF) model running at 2 km horizontal resolution using the North American Regional Reanalysis (NARR) as initial and lateral boundary conditions. Four retrospective years will be shown. Results from four Pseudo Climate simulations (Hara et al. 2008) using the four retrospective runs as the baseline will also be presented. These simulations will be forced by the mean monthly climate signal difference between current (1995 - 2004) and 2045-2055 mean conditions. The NCAR CCSM3 A1B AR4 climate runs with 6 hourly output will be used for the current and future climate model forcings.

Rasmussen, R.; Grubisic, V.

2010-09-01

241

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

NASA Astrophysics Data System (ADS)

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 cause the service breakdowns and damage the infrastructures in the built-up areas and the forest heritage. Critical situations due to the snow loading and the snow removal necessity involve all the mountain people directly. Over the plain and the hill country, where the new snow density is generally high giving rise to effects related to its load capacity, to the isolation of little residential and rural settlements, several damages on the secondary road system due to the tree and tree branch falls comes up , together with many public services interruptions (electric power and telephone), warehouse and barn collapses, determining a widespread critical situation. The urban and commuting traffic during the snow emergency enhances the difficulties related to the road management and traffic control over the whole road system in the plains, even with little snow accumulation on the ground. Critical situations may also arise from road frost and intense freezing spells. The operational implementation of the technical rules for the snow emergency management, tested the first time during the event in a dynamic way, pointed out its drawbacks and potentiality, highlighting the "emergency preparedness" importance at different institutional levels, with the population and stakeholder involvement. Some measures have to be especially underlined: the coordination of the snow monitoring over the territory performed by the local operators (avalanche activity and linked damages reporting) and the steps taken locally; the improvement of the tools for the snow pack evaluation to drive the avalanche artificial triggering off, in case of snow mass hazard assessment, and their regional coordination. Moreover it is important to define the standard, acknowledged and accepted prevention actions suited to minimize the heavy snowfall effects, with particular attention to the viableness,to the school systemopening/closing and to the preventive information care in order to avoid the missing perception of the risk. Special attention must be paid to the hydrogeological risk condition ass

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

2009-09-01

242

High-Latitude Martian Impact Paleolakes: The Possible Contribution of Snowfall and Ancient Glaciers in the Lacustrine Activity Associated to Argyre and Hellas  

NASA Technical Reports Server (NTRS)

Hellas and Argyre show impact crater paleolakes, which morphologies could have been associated to glacial and sub-glacial processes, implying the existence of snowfall and ancient glaciers. Some of them show as well a hydrothermal contribution related to the presence of volcanic centers. Additional information is contained in original extended abstract.

Cabrol, N. A.; Grin, E. A.

2000-01-01

243

The effect of orography and sea surface temperature on the heavy snowfall for the eastern region of Korea : A case study with high resolution WRF simulation  

NASA Astrophysics Data System (ADS)

An analysis of the heavy snowfall that occurred on 11-14 February 2011 in the Yeongdong region along the eastern coast of Korea is presented. Relevant characteristics based on observation and model simulations are discussed with a focus on the times of maximum snowfall in Gangneung (GN) and Daegwallyong (DG). This event was considered part of the typical snowfall pattern that frequently occurs in the Yeongdong region due to the prevailing northeasterly flow. The control simulation using the high resolution Weather Research and Forecasting (WRF) model (1km X 1km) showed reasonable performance in capturing the spatial distribution and temporal evolution of precipitation. The area of precipitation maxima appeared to propagate from the plain coastal region further into the inland mountainous region, in relation to the location of convergence zone. In addition, two sensitivity experiments, EXP1 with a smoothed topography and EXP2 with a warmer sea surface temperature (SST), were performed to investigate the effect of topography and SST on the formation of heavy snowfall. EXP1 tended to modify the precipitation distribution, while EXP2 tended to produce more precipitation over the ocean. Acknowledgements This work was supported by a grant (code No. 3100-3136-442) funded by the National Institute of Meteorological Research (NIMR), the Korea Meteorological Administration (KMA)

Jung, S.-H.; Im, E.-S.; In, S.-R.; Han, S.-O.

2012-04-01

244

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

245

A 750-yr record of autumn snowfall and temperature variability and winter storminess recorded in the varved sediments of Bear Lake, Devon Island, Arctic Canada  

Microsoft Academic Search

The varve record from High Arctic, proglacial Bear Lake reveals a regionally coherent hydroclimatic signal as well as complexities due to changing hydroclimatic and limnologic conditions. Varve formation is strongly dependent on underflows that exhibit variability in strength during the past 750 yr. Periods with reduced underflow sedimentation and accumulation rates fail to produce varves in the distal part of

Scott F. Lamoureux; Robert Gilbert

2004-01-01

246

Jet streak circulations associated with a moderate snowfall event as diagnosed from NGM model output. [Nested Grid Model  

NASA Technical Reports Server (NTRS)

The existence, evolution, and interaction of vertical circulations associated with upper-level jet streaks during a moderate snowfall event are diagnosed using a nested grid model (NGM). The event itself is overviewed, and the diagnosis of transverse circulations utilizing NGM output is discussed. Focus is placed on the identification of the horizontal and vertical components of the circulation, the temporal evolution of the circulation, and the comparison of the circulation from successive model forecasts. A preliminary analysis of the model data indicates that the horizontal and vertical branches of the circulations can be diagnosed from the model output, and the horizontal and vertical components of the circulations may be identified and followed during an individual forecast cycle.

Kocin, Paul J.; Uccellini, Louis W.; Skillman, William C.; Grumm, Richard H.

1989-01-01

247

Winter Storm (weather)  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. First think about these questions: 1. What is your favorite aspect of winter weather? 2. How does the weather effect your everyday life? Form groups of THREE. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper... 1. In general, when are winds formed? 2. When winds are blowing, how can you ...

Miller, Aubree

2009-09-28

248

The Fabled Maine Winter  

NSDL National Science Digital Library

No study of Maine weather would be complete without analysis of the year of 1816 - the year with no summer in an area from western Pennsylvania and New York, up through Quebec and across to Maine and the Canadian maritimes. In this five-unit lesson, students will investigate the causes and effects of the Fabled Maine Winter by exploring a variety of data sources. They will locate, graph, and analyze meteorological and climatological data for Portland, Maine, for more recent years to try to find one that most closely resembles the fabled Maine winter of 1816.

249

Winter depression and diabetes.  

PubMed

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

Ernst, Christine R

2012-12-01

250

Winter Biological Processes Could Help Convert Arctic Tundra to Shrubland  

Microsoft Academic Search

In arctic Alaska, air temperatures have warmed 0.5 degrees Celsius (?C) per decade for the past 30 years, with most of the warming coming in winter. Over the same period, shrub abundance has increased, perhaps a harbinger of a conversion of tundra to shrubland. Evidence suggests that winter biological processes are contributing to this conversion through a positive feedback that

MATTHEW STURM; JOSH SCHIMEL; GARY MICHAELSON; JEFFREY M. WELKER; STEVEN F. OBERBAUER; GLEN E. LISTON; JACE FAHNESTOCK; VLADIMIR E. ROMANOVSKY

2005-01-01

251

WINTERING OF LESSER GOLDEN-PLOVERS IN EASTERN NORTH AMERICA  

Microsoft Academic Search

Although said to winter entirely in southern South America, Lesser Golden- Plovers (Pluvialis dominica dominica) have been recorded in eastern North America in small numbers throughout the winter. A literature search indicates that records are regular through December, most of them probably of late fall migrants, and again increase in late February, probably of early spring migrants. There are at

DENNIS R. PAULSON; DAVID S. LEE

252

Winter streamflow variability, Yukon Territory, Canada  

NASA Astrophysics Data System (ADS)

Knowledge of winter streamflow regimes is required in northern catchments to evaluate water supply and to assess the vulnerability of aquatic habitat. The objective of this study was to explore the nature and causes of winter streamflow variability in northern rivers through examination of a limited number of case studies involving intensive field measurements, as well as a synoptic analysis of winter streamflow measurements archived by Water Survey of Canada for rivers in Yukon Territory, Canada. Evidence was found for an abrupt decrease in discharge at freeze-up in one of the case studies and for 10 of the 25 stations in the synoptic analysis that had measurements within 30 days of freeze-up (an additional 12 stations had no measurements within 30 days of freeze-up). However, given the paucity of measurements in the early winter, the magnitude, duration and frequency of these events cannot be specified. The case studies indicate that, even where a coherent depression does not occur, discharge can fluctuate around a smooth recession trend for about the first 30 days after the onset of ice effects, probably as a result of transient storage and release of water behind ice jams. A storage-depletion model that represents streamflow as outflow from two parallel linear reservoirs provided a reasonable fit to most of the observed measurements (excluding those in the first 30 days following freeze-up), with model fit deteriorating with increasing latitude and decreasing catchment size. The effect of latitude could relate to abstraction of flow by ice production, which would cause deviations from a storage-depletion trend. Northern catchments also tended to have steeper late-winter recessions, which could reflect a lack of extensive, deep aquifers to maintain late-winter discharge. The tendency to poorer model fit in smaller catchments could reflect a problem with data reliability, since it is more difficult to find good winter gauging sections in smaller streams. Some evidence for temperature-related discharge fluctuations was found in both the case studies and synoptic analyses. However, the magnitude of these effects appears to be about +/-10 to 15%, at most, and not to be consistent between winters. Further advances in understanding winter streamflow variability will require frequent measurements on a range of streams over a number of winters.

Moore, R. D.; Hamilton, A. S.; Scibek, J.

2002-03-01

253

ANNUAL WINTER SCHOOLANNUAL WINTER SCHOOL Petersburg Nuclear Physics Institute  

E-print Network

ANNUAL WINTER SCHOOLANNUAL WINTER SCHOOL Petersburg Nuclear Physics Institute National Research February ­ 1 March, 2014 Petersburg Nuclear Physics Institute (PNPI) conducts the XLVIII Annual Winter Physics · Theoretical Physics School · School on Nuclear Reactor Physics · Accelerator Physics School

Titov, Anatoly

254

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

NASA Astrophysics Data System (ADS)

Each year since 2000, the NASA Goddard History of Winter (HOW) program has allowed teachers to develop an understanding of the consequences of one segment of the orbit of the tilted Earth in its path around the sun. Scientists from NASA, CRREL, and Michigan Tech, supported by the Whiteface Observatory, and the science program at Northwood School in Lake Placid, New York, use the weather and the stratigraphy in the ice and snow, consequences of the weather changes, as "teachers" in a team study of the winter record. Snow in the air and on the ground, ice, its crystal structure and axial orientation, and the ecosystem consequences of snow and ice constitute the weeklong content package. Teacher Professional Development Standards A, B, C, and D were the guiding principles in developing HOW with a content structure formulated as protocols to serve as inserts into lesson plans and inquiry guides. The concept of HOW within NASA is to provide understanding of the WHY? and WHAT? of satellite remote sensing. The content is appropriate ground validation in that techniques presented in protocols are identical to those used by professionals who study snow pits, evaluate features in snow metamorphism, and study thin sections of ice cores drilled in ice caps and glaciers. The HOW Teacher as scientist (TAS) model is a flexible model. HOW enables teachers who are required to use inquiry-based facilitation in the classroom to experience inquiry themselves. Teachers with little science content background as well as those with Science degrees have participated in HOW working alongside of the science team. Accommodations are made through differentiation of instruction so that each group leaves with a mastery of the content that is appropriate for the transition to presentation in the classroom. Each year builds on the previous year ensuring a time series record of the history of winter-by itself a learning experience. An offshoot of the NASA Goddard Center History of Winter (HOW) Program, the Global Snowflake Network (GSN) launched in the winter of 2006 engages an international audience including both formal and informal education groups. The goal is to provide an interactive online data resource in science and education for the characterization of snowfall and related weather systems. The Global Snowflake Network has been accepted as an education outreach proposal for the International Polar Year. Collaborations with other agencies and universities also with IPY-accepted proposals are now underway. HOW and the GSN are endorsed by the NASA Goddard Education Office and many of the Goddard Snow and Ice 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.

Gabrys, R. E.

2007-12-01

255

Deciduous Plant Twigs in Winter  

ERIC Educational Resources Information Center

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

Clark, Eloise

1977-01-01

256

winter 2015 Health Informatics  

E-print Network

Health informatics sept. 24 142MHi216 $1,200 interoperability and Health information exchange sept. 24fall 2014/ winter 2015 Health Informatics Health Information Exchange Healthcare Analytics COntin: Health Informatics, Health Information Exchange and Healthcare Analytics. These programs are geared

California at Davis, University of

257

Winter Playscape Dreaming  

ERIC Educational Resources Information Center

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

Keeler, Rusty

2006-01-01

258

Teaching Ecology in Winter.  

ERIC Educational Resources Information Center

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

Clearing: Nature and Learning in the Pacific Northwest, 1984

1984-01-01

259

Announcement Cryptography { Winter 2001  

E-print Network

Announcement Cryptography { Winter 2001 A course in Cryptography is scheduled to be o#11;ered) and a computing course (AM 2120 or CS 2710 or CS 2602). Suggested Text: \\Cryptography { Theory and Practice, but doing so #12;rst requires a discussion of the discrete logarithm problem). 5. Public-Key Cryptography

deYoung, Brad

260

Mammals in Winter.  

ERIC Educational Resources Information Center

Mammals that tolerate the winter cold and stay active all year exploit the harsh northern climate to their advantage. By simple experiments and observation you can better understand their adaptations which include furry bodies, snowshoe feet, extra blubber, light coloration, and strategically distributed food caches. (JHZ)

Wapner, Suzanne

1985-01-01

261

WINTER 2014 Sustainability and  

E-print Network

WINTER 2014 Sustainability and Renewable Energy in Costa Rica January 4 - 14 Dr. James Hoffmann, Program Director Lecturer Sustainability Studies Program E-511 Melville Library Stony Brook, NY 11794 sustainability and renewable energy. Students will spend 11 days in Costa Rica to participate in site visits

Stephens, Graeme L.

262

GRAND RIVER Winter 2014  

E-print Network

GRAND RIVER POST SECONDARY BOARD NEWSLETTER Winter 2014 Issue 55 P.O. Box 339 Ohsweken ON, N0A 1M0-mail: info@grpseo.org Website: www.grpseo.org Grand River Post Secondary Board Members Brenda Davis (Chair TO TOMORROW Onkwehon:we with Grand River Territory lineage are empowered through higher education within

Thompson, Michael

263

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

NASA Astrophysics Data System (ADS)

Rising air temperatures have profoundly impacted British Columbia (BC) mountain ecosystems, including its Interior Wetbelt. This region supports the sole Interior Temperate Rainforest (ITR), or perhaps more appropriately "snowforest", of North America. This snowforest encompasses about 30,500 km2 and contains Western redcedar (Thuja plicata) and western hemlock (Tsuga heteropylla) in excess of 1500 years old. This region is projected to be one of the more vulnerable biogeoclimatic zones in BC due to forest operations and climate change. Loss of snow as a storage medium has the potential to negatively affect the forest. A decrease in snow water equivalent (SWE) has the potential to decrease soil moisture values; impacts of decreased water availability in this region have the possibility to affect soil moisture storage, vegetative species composition, flora and fauna interdependence, and pathogen outbreaks. Given the projected climate change in high latitude and altitude areas, this project analyzes the contemporary and potential future climate of BC's Interior Wetbelt and explores the possible environmental and ecohydrological impacts of climate change on the snowforest. Models project an increase in air temperature and precipitation but a decrease in snowfall in this region. Analyses of the snow depth, SWE, and temperature from the Upper Fraser River Basin automated snow pillow sites of the BC River Forecast Centre (RFC) were conducted; snow depth, SWE, and temperature were also measured at the field site via automated weather stations and bi-monthly snow surveys. Surveys recorded depth and SWE after observed peak accumulation and continued until snowpack was depleted in 80% of the field site. To determine the influence of precipitation on the soil moisture levels in the ITR, soil moisture and water table levels were measured for the 2011-12 water year in addition to meteorological conditions; snow, spring water, and near surface ground water samples were collected and analyzed for the environmental isotopes of deuterium and oxygen-18. Analysis of the RFC's snow pillow data shows April 1 snow depth has been highly variable in the last 25 years with an overall decline in depth and SWE values. Soil moisture values at the study site were consistent through the year but showed a peak during spring melt and a decline during August, the driest month of summer in this region. Isotopic analysis on the water samples is on-going. The Upper Fraser River Basin experienced an above-normal to record snowpack the winter of 2011-12, thus observed values may not be indicative of the overall trend for this area. Trends in this interconnected ecosystem can assist in determining impacts of climate change to northern climates.

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

2012-12-01

264

Measuring Transpiration to Regulate Winter Irrigation Rates  

SciTech Connect

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

Samuelson, Lisa [Auburn University] [Auburn University

2006-11-08

265

Winter Wilderness Travel and Camping.  

ERIC Educational Resources Information Center

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…

Gilchrest, Norman

266

Lightning Protection against Winter Lightning  

Microsoft Academic Search

Winter lightning, which occurs along the Sea of Japan coast, often damages transmission lines and distribution lines with the conventional lightning protection. These lines in mountainous areas suffer extensive damage from winter lightning. It is very important to investigate the features of lightning outages in detail to improve the lightning protection measures against winter lightning, therefore observations of lightning strokes

Hitoshi Sugimoto

2007-01-01

267

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

NASA Astrophysics Data System (ADS)

The Laurentian Great Lakes developed their most extensive ice cover in over a decade during winter 1994 [December-February 1993/94 (DJF 94)]. Extensive midlake ice formation started the second half of January, about 2 weeks earlier than normal. Seasonal maximal ice extent occurred in early February, again about 2 weeks earlier than normal. Winter 1994 maximum (normal) ice coverages on the Great Lakes are Lake Superior 96% (75%), Lake Michigan 78% (45%), Lake Huron 95% (68%), Lake Erie 97% (90%), and Lake Ontario 67% (24%). Relative to the prior 31 winters (1963-93), the extent of seasonal maximal ice cover for winter 1994 for the Great Lakes taken as a unit is exceeded by only one other winter (1979); however, other winters for individual Great Lakes had similar maximal ice covers.Anomalously strong anticyclonic circulation over the central North Pacific (extending to the North Pole) and an abnormally strong polar vortex centered over northern Hudson Bay combined to produce a circulation pattern that brought frequent air masses of Arctic and polar origin to the eastern third of North America. New records were set for minimum temperatures on 19 January 1994 at many locations in the Great Lakes region. A winter severity index consisting of the average November-February air temperatures averaged over four sites on the perimeter of the Great Lakes (Duluth, Minnesota; Sault Ste. Marie, Michigan; Detroit, Michigan; and Buffalo, New York) indicates that winter 1994 was the 21st coldest since 1779. The unseasonably cold air temperatures produced much-above-normal ice cover over the Great Lakes and created problems for lake shipping. Numerous fatalities and injuries were attributed to the winter weather, which included several ice and snow storms. The much-below-normal air temperatures resulted in enhanced lake-effect snowfall along downwind lake shores, particularly during early to midwinter, prior to extensive ice formation in deeper lake areas. The low air temperatures were also responsible for record 1-day electrical usage and multimillion dollar costs associated with snow removal, U.S. and Canadian Coast Guard operational assistance to ships beset in ice, damage to ships by ice, damage to public and private property by river ice jams and associated flooding, frozen underground water pipes, and damage to fruit trees.

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

1996-01-01

268

Wintering site interchange amongst Greenland White-fronted Geese Anser albifrons flavirostris captured at Wexford Slobs, Ireland  

Microsoft Academic Search

The maximum count of Greenland White-fronted Geese wintering at Wexford, south-east Ireland (where over a third of the population winters) increased from 7910 in 1984\\/85 to 9530 in 1989\\/90. Although the population tends to be highly site-loyal on the wintering grounds, 14% of 700 marked geese seen in two consecutive winters changed site. Counts elsewhere in the wintering range and

S. M. Warren; A. J. Walsh; O. J. Merne; H. J. Wilson; A. D. Fox

1992-01-01

269

Social Media Plan #WinterPrep  

E-print Network

! #winter http://www.nssl.noaa.gov/education/svrwx101/winter/types/ Ice Jams Facebook Ice jams can occur downstream. http://www.floodsafety.noaa.gov/hazards.shtml Twitter Ice jams in rivers about winter safety by using #WinterPrep in your tweets! Winter Safety Winter Precipitation Ice

270

Titan's Winter Polar Vortex  

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

271

Snow line analysis in the Romanian Carpathians under the influence of winter warming  

NASA Astrophysics Data System (ADS)

The Romanian Carpathians are subject to winter warming as statistically proved by station measurements over a 47 year period (1961-2007). Herein, the snow season is considered to last from the 1st of November to the 30th of April, when snowpack usually reaches the highest stability and thickness. This paper investigates the signals of winter temperature and precipitation change at 17 mountain station located above 1,000 m, as being considered the main triggering factors of large fluctuations in snow amount and duration in these mountains. Fewer snowfalls were recorded all over the Romanian Carpathians after the mid 80s and over large mountain areas (including the alpine ones) the frequency of positive temperature extremes became higher (e.g. winter heat waves). Late Fall snowfalls and snowpack onsets (mainly in mid elevation areas, located below 1,700 m) and particularly the shifts towards early Spring snowmelts (at all the sites) were statistically proved to explain the decline of snow cover duration across the Carpathians. However, the sensitivity of snow cover duration to recent winter warming is still blurred in the high elevation areas (above 2,000 m). The trends in winter climate variability observed in the Romanian Carpathians beyond 1,000 m altitude are fairly comparable to those estimated in other European mountain ranges from observational data (e.g. the Swiss Alps, the French Alps and the Tatra Mts.). In relation to the climate change signals derived from observational data provided by low density mountain meteorological network (of about 3.3 stations per km2 in the areas above 1,000 m), the paper analysis the spatial probability and evolution trends of snow line in each winter season across the Romanian Carpathians, based on Landsat satellite data (MSS, TM and ETM+), with sufficiently high spatial (30 to 60 m) and temporal resolutions (850 images), over the 1973-2011 period. The Landsat coverage was considered suitable enough to enable an objective statistical assessment of snow line and snow cover change across the Carpathians, providing results obtained for the first time in the national specialist literature on this topic. The satellite images were bulk processed for calibration to radiance and reflectance and the Normalized Difference Standardized Index (NDSI) and Land Surface Temperature (LST) have been extracted (the latter, only for TM and ETM+) and validated with ground meteorological measurements. All NDSIs and LSTs were merged into distinct monthly images covering the entire mountain range for each 38 winters in the study period. A quantitative analysis of snow line elevation change in relation to the variability of freezing level has been conducted. The snow line change across the Romanian Carpathians derived from satellite imagery has been used as a proxy for local response of the Carpathian climate to the warming process also observed in other mountain regions of Europe. The winter warming observed in the last decades caused an upward shift of the snow line and freezing level, associated to a shrinking of snow cover area all over the Carpathians, particularly after 2000. The paper's findings explain partially the difficulties that winter tourism industry in Romania has been facing in the last years due to the lack of snow or poor snow coverage, particularly in the low elevation ski domains located below the snow reliability line

Micu, Dana; Cosmin Sandric, Ionut

2013-04-01

272

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

NASA Astrophysics Data System (ADS)

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 species of mammals, birds, and insects have begun to reproduce and overwinter at our field site in the past decade, and hibernators have changed the phenology of emergence from hibernation. Marmots now put on much more fat before entering hibernation. Interactions among species such as pollination and seed predation have also been affected by the changes in snowpack and phenology. For example, although both migratory hummingbirds and their floral resources are changing phenology, they are not changing at the same rate, leading to mismatches in their historical synchrony; hummingbirds now arrive well after their earliest food plant has begun to flower. A similar loss of synchrony appears to be affecting bumble bees as they emerge from overwintering underground, and one of their earliest nectar sources. Seed predator flies and moths, and their parasitoids, are probably being affected by the absence of seeds from species sensitive to frost. Thus many aspects of high-altitude ecological communities are being affected by the ongoing changes in depth of winter snowpack and the timing of its melting.

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

2012-12-01

273

Desiccation-tolerance of Fagus crenata blume seeds from localities of different snowfall regime in central Japan  

Microsoft Academic Search

In beech (Fagus crenata Blume) forests on the Pacific Ocean side in Central Japan, snowpack depth is little and xeric conditions may prevail in winter,\\u000a in contrast to heavy snow in beech forests on the Japan Sea side. The effects of such conditions during winter on the viability\\u000a of beech seeds were studied at a beech forest on the Pacific

Emiko Maruta; Tomohiko Kamitani; Midori Okabe; Yuji Ide

1997-01-01

274

Winter Storm Warning  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

2009-09-28

275

Winter weather activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Weather Maker Simulator Use the weather simulation above to answer the following questions in complete sentences on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there is high ...

Frankovic, Whitney

2009-09-28

276

Storm Winter Activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

KateOlsen58

2009-09-28

277

Winter Storm Activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

Barbieri, Mikel

2012-02-13

278

Winter Storm Activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

Ferraratechclassroom

2012-02-06

279

Al's Winter Storm Activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

Al

2010-02-22

280

Winter Storm Activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

Butcher, Kirsten

2008-09-26

281

Winter Storm Activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? What is a better indicator of moisture in the air? 4. What happens when there is low ...

Xuan

2010-02-22

282

NHS healthcare workers prepare for winter's double whammy.  

PubMed

As temperatures drop, pressure on the NHS rises. So winter, with its increased levels of sickness and higher numbers of emergency admissions particularly of frail older people, is always a challenge. PMID:25315539

2014-10-21

283

ENCS 307: ENVIRONMENTAL ASSESSMENT PRINCIPLES AND METHODS SECOND (WINTER) TERM  

E-print Network

-1- ENCS 307: ENVIRONMENTAL ASSESSMENT PRINCIPLES AND METHODS SECOND (WINTER) TERM Instructor Dr. Grading Assignments 50% Exams 50% Course Description Environmental assessments are becoming more common as increasing regulatory requirements are developed. Information collected for environmental assessments must

Erbilgin, Nadir

284

Fall/ Winter 2003 In this issue  

E-print Network

pastor in Quebec City re- corded in his diary entry for June 8th: "Bleak, cold, very uncommon weather." There are contem- porary references to snow drifts up to the axles of carriages in Quebec City. The snowstorm for significant snowfall in post-1951 modern weather records at Quebec City is May 6. The late snowstorm occurred

Hamilton, Kevin

285

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

PubMed

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

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

2014-11-01

286

Impact of warm winters on microbial growth  

NASA Astrophysics Data System (ADS)

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 temperature relationships of the bacterial community from winter-warmed plots and plots with ambient soil temperatures were compared. No change in optimum temperature for growth could be detected, indicating that the microbial community has not been warm-adapted. This fits with what was seen also in the laboratory experiment where no changes in temperature response occurred when exposing bacteria to temperatures below 10 °C within two months. The increase in activity measured during winter should thereby be due to changes in environmental factors, which will be further investigated. One big difference between heated and control plots was that heated plots were snow free during the entire winter, while control plots were covered by a 10 cm snow cover. The plant community composition and flowering time also differed in the warmed and ambient plot.

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

2014-05-01

287

Winter Frost and Fog  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

288

Big6 Winter Production  

NSDL National Science Digital Library

Goals: a. Students will be able to identify the four seasons. b. Students will be able to identify three animals (bear, goose, moose) and know their lifestyle patterns in congruence with the four seasons, especially Winter months. c. Students will develop an understanding of their environment. 2nd Grade Standard III: Students will develop an understanding of their environment Objective 2: Observe and describe weather Goal C: Describe how weather affects people and weather Lesson Objectives: a. Identify the seasons and represent each with pictures and songs. b. Observe and describe typical weather for each of ...

Cook, Mrs.

2010-11-05

289

winter storm activity  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. It provides an interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

Prested, Miss

2010-05-26

290

Ensemble Applications in Winter  

NSDL National Science Digital Library

This lesson provides an introduction to ensemble forecast systems using an operational case study of the Blizzard of 2013 in Southern Ontario. The module uses models available to forecasters in the Meteorological Service of Canada, including Canadian and U.S. global and regional ensembles. After briefly discussing the rationale for ensemble forecasting, the module presents small lessons on probabilistic ensemble products useful in winter weather forecasting, immediately followed by forecast applications to a southern Ontario case. The learner makes forecasts for the Ontario Storm Prediction Center area and, in the short range, for the Toronto metropolitan area. An additional section applies a probabilistic aviation product to forecasts for Toronto Pearson International Airport.

COMET

2014-04-22

291

Winter thunderstorms in central Europe in the past and the present  

NASA Astrophysics Data System (ADS)

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

Munzar, Jan; Franc, Marek

292

Enroll now: winter.edm.vt.edu Winter 2015 Calendar  

E-print Network

& Literatures Spanish Course Descriptions: Winter 2015 SPAN 2774: Minority Languages Examination of language policies and practices with regard to minority languages across the Spanish-speaking context, histories of minority languages in Spanish- speaking areas

Buehrer, R. Michael

293

Increased snow facilitates plant invasion in mixedgrass prairie.  

PubMed

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

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

2008-07-01

294

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

NASA Astrophysics Data System (ADS)

Studies on recent climate trends from the Himalayan range are limited, and even completely absent at high elevation. This contribution specifically explores the southern slopes of Mt. Everest (central Himalaya), analyzing the minimum, maximum, and mean temperature and precipitation time series reconstructed from seven stations located between 2660 and 5600m a.s.l. over the last twenty years (1994-2013). We complete this analysis with data from all the existing ground weather stations located on both sides of the mountain range (Koshi Basin) over the same period. Overall we observe that the main and more significant increase in temperature is concentrated outside of the monsoon period. At higher elevations minimum temperature (0.072 ± 0.011 °C a-1, p < 0.001) increased far more than maximum temperature (0.009 ± 0.012 °C a-1, p > 0.1), while mean temperature increased by 0.044 ± 0.008 °C a-1, p < 0.05. Moreover, we note a substantial precipitation weakening (9.3 ± 1.8mm a-1, p < 0.01 during the monsoon season). The annual rate of decrease at higher elevation is similar to the one at lower altitudes on the southern side of the Koshi Basin, but here the drier conditions of this remote environment make the fractional loss much more consistent (47% during the monsoon period). This study contributes to change the perspective on which climatic driver (temperature vs. precipitation) led mainly the glacier responses in the last twenty years. The main implications are the following: (1) the negative mass balances of glaciers observed in this region can be more ascribed to less accumulation due to weaker precipitation than to an increase of melting processes. (2) The melting processes have only been favored during winter and spring months and close to the glaciers terminus. (3) A decreasing of the probability of snowfall has significantly interested only the glaciers ablation zones (10%, p < 0.05), but the magnitude of this phenomenon is decidedly lower than the observed decrease of precipitation. (4) The lesser accumulation could be the cause behind the observed lower glacier flow velocity and the current stagnation condition of tongues, which in turn could have trigged melting processes under the debris glacier coverage, leading to the formation of numerous supraglacial and proglacial lakes that have characterized the region in the last decades. Without demonstrating the causes that could have led to the climate change pattern observed at high elevation, we conclude by listing the recent literature on hypotheses that accord with our observations.

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

2014-12-01

295

Dissolved organic matter composition of winter flow in the Yukon River basin: Implications of permafrost thaw  

E-print Network

Territories (Canada) highlight a long-term increase in winter streamflow, 1 U.S. Geological Survey, BoulderDissolved organic matter composition of winter flow in the Yukon River basin: Implications; published 17 November 2012. [1] Groundwater discharge to rivers has increased in recent decades across

Ickert-Bond, Steffi

296

Winter fuels report  

SciTech Connect

The Winter Fuels Report is intended to provide concise, timely information to the industry, the press, policymakers, consumers, analysts, and State and local governments on the following topics: Distillate fuel oil net production, imports and stocks on a US level and for all Petroleum Administration for Defense Districts (PADD) and product supplied on a US level; propane net production, imports and stocks on a US level and for PADD`s I, II, and III; natural gas supply and disposition and underground storage for the US and consumption for all PADD`s; as well as selected National average prices; residential and wholesale pricing data for heating oil and propane for those States participating in the joint Energy Information Administration (EIA)/State Heating Oil and Propane Program; crude oil and petroleum price comparisons for the US and selected cities; and a 6-10 Day, 30-Day, and 90-Day outlook for temperature and precipitation and US total heating degree-days by city.

Not Available

1994-10-01

297

Winter fuels report  

SciTech Connect

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

Not Available

1990-10-04

298

The Challenge of Winter Backpacking.  

ERIC Educational Resources Information Center

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

Cavanaugh, Michael; Mapes, Alan

1981-01-01

299

PHYSICS 122 LABORATORY (Winter, 2014)  

E-print Network

- 1 - PHYSICS 122 LABORATORY (Winter, 2014) COURSE GOALS 1. Learn how Chiang 235 Physics chiang@physics.ucdavis.edu 402-7113 Tony Tyson 514 Physics tyson@physics.ucdavis.edu 752-3830 TEACHING ASSISTANTS: Joe Mitchell 512

Yoo, S. J. Ben

300

PHYSICS 122 LABORATORY (Winter, 2015)  

E-print Network

- 1 - PHYSICS 122 LABORATORY (Winter, 2015) COURSE GOALS 1. Learn how Tyson 514 Physics tyson@physics.ucdavis.edu 752-3830 Xiangdong Zhu 235 Physics zhu@physics.ucdavis.edu 402-7113 TEACHING ASSISTANTS: Andrew Bradshaw 518

Yoo, S. J. Ben

301

Snowfall in Southern Appalachia  

NASA Technical Reports Server (NTRS)

The snowstorm which swept across the eastern United States on December 4 and 5 also brought the season's first snow to parts of the south and southern Appalachia. The extent of snow cover over central Kentucky, eastern Tennessee, western North Carolina and Virginia are apparent in this view from the Multi-angle Imaging SpectroRadiometer (MISR). This natural-color image was captured by MISR's downward-looking (nadir) camera on December 7, 2002.

The Appalachians are bounded by the Blue Ridge mountain belt along the east and the Appalachian Plateau along the west. Valleys and ridges between the higher elevation areas retain the green and reddish-brown hues of autumn, and many rivers and lakes appear blue and unfrozen. The highest peak in the eastern United States, Mount Mitchell, is found in North Carolina's western tip, near the Great Smoky Mountains (the dark-colored range at lower right).

The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. This data product was generated from a portion of the imagery acquired during Terra orbit 15805. The image covers an area of 347 kilometers x 279 kilometers, and utilizes data from blocks 60 to 62 within World Reference System-2 path 19.

2002-01-01

302

Movements of wintering Dunlin Calidris alpina and changing habitat availability in an agricultural wetland landscape  

USGS Publications Warehouse

Few studies have assessed how the dynamics of wetland bird movements relate to changing resource availability, particularly at more than one spatial scale. Within western Oregon's Williamette Valley, we examined winter resident Dunlin Calidris alpina movements in relation to a decrease in availability of preferred shorebird foraging habitat from early to late winter of 1999-2000. By tracking movements of 15 (early winter) and 12 (late winter) radiomarked individuals, we calculated home ranges and characterized presence/absence of a preference for shorebird foraging habitat during each winter period. Between periods, we compared: (1) percentage of shorebird habitat in home ranges to its availability in the landscape (regional preference), (2) percentage of radio locations in shorebird habitat to its availability within home ranges (local preference) and (3) relative use of roost sites. Concurrent with a 75% decrease in available shorebird habitat from early to late winter, average home range sizes increased by a factor of 3.8. At a regional scale, home ranges in early winter included a significantly greater percentage of shorebird foraging habitat than was available in the wider landscape. However, by late winter, the percent of shorebird habitat in home ranges did not match availability in the landscape. At the local scale, for both winter periods Dunlin were located in shorebird foraging habitat more often than expected given availability of habitat within home ranges [Correction added after online pub-lication 23 May 2008: sentence amended]. An increase in the number of roosts used from early to late winter implies possible reliance on additional sites in late winter for foraging opportunities. Results suggest that wet, unvegetated habitat is sought by Dunlin throughout winter, but individuals could not select home ranges in late winter that fully compensated for seasonal loss of habitat. ?? 2008 The Authors.

Taft, O.W.; Sanzenbacher, P.M.; Haig, S.M.

2008-01-01

303

Confounded winter and spring phenoclimatology on large herbivore ranges  

USGS Publications Warehouse

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.

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

2013-01-01

304

Modeling Winter Cereal Grain Canopies for Legume Intercrop Establishment  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

305

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

USGS Publications Warehouse

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

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

1988-01-01

306

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

USGS Publications Warehouse

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.

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

2009-01-01

307

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

USGS Publications Warehouse

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 (0-64% of the total Hg mass in the snowpack) suggests that movement of Hg from the soil into the snowpack is possible. However, as with any tracer study the 202Hg tracer may not precisely represent the reactivity and mobility of natural Hg in soils. ?? 2007 Elsevier Ltd. All rights reserved.

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

2008-01-01

308

Winter speed-up of quiescent surge-type glaciers in Yukon, Canada  

NASA Astrophysics Data System (ADS)

Glacier surge is known to often initiate in winter, but the mechanisms remain unclear in light of the summer speed-up at normal glaciers. We examined spatial-temporal changes in the ice velocity of surge-type glaciers near the border of Alaska and Yukon, and found significant upstream accelerations from fall to winter, regardless of surging episodes. Moreover, whereas the summer speed-up was observed downstream, the winter speed-up propagated from upstream to downglacier. Given the absence of upstream surface meltwater input in winter, we speculate the presence of water storages near the base that do not directly connect to the surface but can promote basal sliding through increased water pressure as winter approaches. Our findings have implications for modeling of glacial hydrology in winter time, and its link to glacier dynamics and subglacial erosion.

Abe, T.; Furuya, M.

2014-05-01

309

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

NASA Astrophysics Data System (ADS)

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.

Baldocchi, Dennis; Waller, Eric

2014-05-01

310

The Impact of Winter Heating on Air Pollution in China  

PubMed Central

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

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

2015-01-01

311

The impact of winter heating on air pollution in china.  

PubMed

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

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

2015-01-01

312

The Dallas winter visibility study  

SciTech Connect

For some years, a highly visible cloud of polluted air could be seen over the city during winter season stagnation conditions. A historical study of visual range data collected from local airports conducted by the Texas Air Control Board showed a decreasing trend in the number of good visibility days per year over the past 35 years and, that the average visibility has decreased by 50 percent since 1940. Specific data describing the haze composition or source contributions to the winter pollution haze were limited. The purpose of this study, was to determine the composition of the visible haze, and from that information, determine the relative contribution of the various air pollution sources in the Dallas area to winter visibility impairment. Two existing air quality monitoring stations were augmented with additional instrumentation for this study. 18 figs., 18 tabs.

Einfeld, W.; Dattner, S.; Zimmermann, K.

1988-09-01

313

Physiological responses of Yellowstone bison to winter nutritional deprivation  

USGS Publications Warehouse

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.

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

1994-01-01

314

Winter climate change: a critical factor for temperate vegetation performance.  

PubMed

Winter ecological processes are important drivers of vegetation and ecosystem functioning in temperate ecosystems. There, winter conditions are subject to rapid climate change. The potential loss of a longer-lasting snow cover with implications to other plant-related climate parameters and overwintering strategies make the temperate zone particularly vulnerable to winter climate change. A formalized literature search in the ISI Web of Science shows that plant related research on the effects of winter climate change is generally underrepresented. Temperate regions in particular are rarely studied in this respect, although the few existing studies imply strong effects of winter climate change on species ranges, species compositions, phenology, or frost injury. The generally positive effect of warming on plant survival and production may be counteracted by effects such as an increased frost injury of roots and shoots, an increased insect pest risk, or a disrupted synchrony between plants and pollinators. Based on the literature study, gaps in current knowledge are discussed. Understanding the relative effects of interacting climate parameters, as well as a stronger consideration of shortterm events and variability of climatic conditions is urgent. With respect to plant response, it would be particularly worthwhile to account for hidden players such as pathogens, pollinators, herbivores, or fungal partners in mycorrhization. PMID:20715613

Kreyling, Juergen

2010-07-01

315

Writing TAFS for Winter Weather  

NSDL National Science Digital Library

"Writing TAFs for Winter Weather" is the fourth unit in the Distance Learning Aviation Course 2 (DLAC2) series on producing TAFs that meet the needs of the aviation community. In addition to providing information about tools for diagnosing winter weather and its related impacts, the module extends the Practically Perfect TAF (PPTAF) process to address an airportâs operational thresholds. By understanding the thresholds at airports for which they produce TAFs, forecasters will be better able to produce a PPTAF. The unit also examines how to communicate effectively the logic and uncertainty using the aviation forecast discussion (AvnFD) and addresses maintaining an effective TAF weather watch and updating the TAF proactively.

Comet

2009-09-22

316

Evidence for continued transmission of parasitic nematodes in reindeer during the Arctic winter  

Microsoft Academic Search

Living in the high Arctic, the Svalbard reindeer (Rangifer tarandus platyrhynchus) and its trichostrongyle nematodes experience a long cold winter from October to late May\\/early June. Over this period, transmission would be expected to be low. However, in culled reindeer the abundance of infection increased from autumn to late winter, providing evidence for continued transmission within this period. To our

O Halvorsen; A Stien; J Irvine; R Langvatn; S Albon

1999-01-01

317

The likely impact of sea level rise on waders (Charadrii) wintering on estuaries  

Microsoft Academic Search

Global climate change may affect the internationally important populations of waders (Charadrii) throughout their annual ranges and in a variety of ways. Within Britain, those waders that winter on estuaries are likely to be affected in two principal manners: increasingly mild winter weather already appears to have affected the distributions of the waders within Britain and rising sea level threatens

Graham E. Austin; Mark M. Rehfisch

2003-01-01

318

Winter Cereal Cover Crop Removal Strategy Affects Spring Soil Nitrate Levels  

Microsoft Academic Search

The use of winter cereal cover crops in no-till row crop systems has increased in the North Central Corn Belt. Timing of the cover crop removal can be managed to improve nitrogen availability for subsequently grown crops. Growers utilizing cover crop systems have several alternatives regarding the removal strategy for the winter cereal cover crop prior to seeding rotational corn

M. R. Jewett; K. D. Thelen

2007-01-01

319

Microbial Biomass and Activities in Soil Aggregates Affected by Winter Cover Crops  

Microsoft Academic Search

vegetable cropping systems (Burket et al., 1997); how- ever, it is unclear whether legumes or nonlegumes are Winter cover crops may increase soil organic matter (SOM) and the most suitable for this task. Leguminous winter cover improve soil structure in intensively managed summer vegetable crop- ping systems. Our study examined the influence of three cover crop crops have the potential

I. C. Mendes; A. K. Bandick; R. P. Dick; P. J. Bottomley

1999-01-01

320

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

ERIC Educational Resources Information Center

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

Matthews, Bruce E.; And Others

321

Natural snowfall reveals large-scale flow structures in the wake of a 2.5-MW wind turbine.  

PubMed

To improve power production and structural reliability of wind turbines, there is a pressing need to understand how turbines interact with the atmospheric boundary layer. However, experimental techniques capable of quantifying or even qualitatively visualizing the large-scale turbulent flow structures around full-scale turbines do not exist today. Here we use snowflakes from a winter snowstorm as flow tracers to obtain velocity fields downwind of a 2.5-MW wind turbine in a sampling area of ~36 × 36?m(2). The spatial and temporal resolutions of the measurements are sufficiently high to quantify the evolution of blade-generated coherent motions, such as the tip and trailing sheet vortices, identify their instability mechanisms and correlate them with turbine operation, control and performance. Our experiment provides an unprecedented in situ characterization of flow structures around utility-scale turbines, and yields significant insights into the Reynolds number similarity issues presented in wind energy applications. PMID:24960397

Hong, Jiarong; Toloui, Mostafa; Chamorro, Leonardo P; Guala, Michele; Howard, Kevin; Riley, Sean; Tucker, James; Sotiropoulos, Fotis

2014-01-01

322

Keep Dogs and Cats Safe During Winter  

MedlinePLUS

... this page, please enable JavaScript. Keep Dogs and Cats Safe During Winter Veterinarian offers tips for helping ... News) -- Winter can be tough on dogs and cats, but there are a number of safe and ...

323

ROV Survey of Winter Quarters Bay  

NSF Publications Database

Title : ROV Survey of Winter Quarters Bay Type : Antarctic EAM NSF Org: OD / OPP Date : January 24 ... Vehicle (ROV) Survey of Winter Quarters Bay) To: File S.7 (Environment) On December 13, 1990, the ...

324

Defending the Axioms Winter 2009  

E-print Network

Defending the Axioms Winter 2009 This course is concerned with the question of how set theoretic axioms are properly defended, of what counts as a good reason to regard a given statement methodological matters -- which axioms and on what grounds? -- and metaphysical/epistemological matters -- what

Barrett, Jeffrey A.

325

Learners in Action, Winter 2006  

ERIC Educational Resources Information Center

This Winter 2006 issue of "Learners in Action" contains the following articles: (1) Premiers Honour Adult Learners; (2) Learning Difficulties?; (3) Awards; (4) Hats off to Jacques Demers!; (5) What Do You Think?; (6) Meet the Current Learners Advisory Network; and (7) "Learning Edge" is No Ordinary Magazine!.

Movement for Canadian Literacy, 2006

2006-01-01

326

Anthropolog Fall 2009/Winter 2010  

E-print Network

page 1 Anthropolog Fall 2009/Winter 2010 Newsletter of The Department of Anthropology National was marked by awards given to several of our colleagues. The Department of Anthropology was recognized.After two years of forensic examination and exhaustive genealogical research, the team, with the assistance

Mathis, Wayne N.

327

UNIVERSITY LIBRARY Winter Quarter 2014  

E-print Network

University Library Town Hall 14 #12;Program Management · Program management not limited to library managersUC DAVIS UNIVERSITY LIBRARY TOWN HALL Winter Quarter 2014 March 4, 2014 UC Davis University Library, including the Q&A portion, from the Library's web site http://lib.ucdavis.edu/dept/admin/plan/ March 4, 2014

Ferrara, Katherine W.

328

Winter Storms For More Information  

E-print Network

-related brochures. You can find more information on flash flooding in the Floods... The Awesome Power brochure site http://www.nws.noaa.gov/om/water/ahps/ pdfs/Floodsbrochure_02_06.pdf. To find additional materials of these threats. · A major winter storm can last for several days and be accompanied by high winds, freezing rain

329

Quantitative Methods II Winter 2012  

E-print Network

1 of 3 Quantitative Methods II Winter 2012 Meets: Thursdays 9am ­ 11:50am Professor: Jonathan.northwestern.edu This course is intended to be a continuation of the quantitative methods sequence that began with Quantitative assumptions are violated. We will then discuss various methods researchers use to overcome these obstacles

Bustamante, Fabián E.

330

2013 Winter Cardinal Softball School  

E-print Network

2013 Winter Cardinal Softball School @ Wesleyan University An opportunity to work on your fastpitch, please complete the form below and mail with check payable to "Cardinal Softball School" by January 7th to: Cardinal Softball School Jen Lane, Director Freeman Athletic Center 161 Cross Street Middletown

Royer, Dana

331

An assessment of the potential and impacts of winter water banking in the Sokh aquifer, Central Asia  

Microsoft Academic Search

The dynamics of artificial recharge of winter surface flows coupled with increased summer groundwater use for irrigation in\\u000a the Sokh aquifer (Central Asia) have been investigated. Water release patterns from the giant Toktogul reservoir have changed,\\u000a as priority is now given to hydropower generation in winter in Kyrgyzstan. Winter flows have increased and summer releases\\u000a have declined, but the Syr

Inna Gracheva; Akmal Karimov; Hugh Turral; F. Miryusupov

2009-01-01

332

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

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Winter Harbor Lobster Boat Race, Winter Harbor, ME. 100.109 Section...100.109 Winter Harbor Lobster Boat Race, Winter Harbor, ME. (a) Regulated...commander may delay, modify, or cancel the race as conditions or circumstances...

2010-07-01

333

MSU University News Winter pea and lentil offer growers a way to diversify winter  

E-print Network

MSU University News Winter pea and lentil offer growers a way to diversify winter wheat systems August 13, 2003 Ag researchers are studying winter peas and lentils to see whether they offer enough yield advantage over spring peas and lentils that they would make a better rotation choice for winter

Maxwell, Bruce D.

334

Clinical Scenario 1 Is Associated With Winter Onset of Acute Heart Failure.  

PubMed

Background:Several reports have evaluated the association between seasonal variation and acute heart failure (AHF) onset. Cold weather may induce AHF, but the clinical characteristics of patients susceptible to AHF during winter have not been established. Clinical Scenario (CS) is used in the early clinical management of AHF, so we investigated the relationship between CS classification and winter onset of AHF in Japan.Methods?and?Results:We enrolled 582 patients hospitalized for AHF and compared the frequency of AHF among the 4 seasons in each CS group to clarify the clinical characteristics of the winter onset group. Significant increase of AHF during winter was seen in CS1 (systolic blood pressure [SBP] (>140 mmHg) (P=0.01) but not in CS2 (SBP ?100 and ?140 mmHg) or CS3 (SBP <100 mmHg). CS1 patients were divided into winter and other season admission groups. In multivariate analysis, only lack of loop diuretic use was associated with winter admission of CS1 patients (odds ratio 0.562, 95% confidence interval: 0.256-0.798, P=0.006).Conclusions:Winter predominance of AHF was seen only in CS1, and lack of loop diuretic use was a risk factor for winter onset. Future studies are necessary to confirm whether loop diuretics are useful in preventing AHF with CS1 in winter. PMID:25421314

Hirai, Masayuki; Kato, Masahiko; Kinugasa, Yoshiharu; Sugihara, Shinobu; Yanagihara, Kiyotaka; Yamada, Kensaku; Watanabe, Tomomi; Yamamoto, Kazuhiro

2014-11-21

335

Water use in a winter camelina – soybean double crop system  

Technology Transfer Automated Retrieval System (TEKTRAN)

Double-cropping winter camelina (Camelina sativa) followed by soybean (Glycine max) may increase land-use efficiency by producing food and biofuel in a single season and is a viable cropping system for the northern Corn Belt. However, regional success of double-cropping, especially under dryland con...

336

Small Grain Winter Cover Crops for Corn and Soybean  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

337

Energetic determinants of abundance in winter landbird communities  

Microsoft Academic Search

There is increasing evidence that individual energetics constrain macroecological patterns. Here we model total abundance within winter landbird communities as a function of (1) energy supply, as measured by ecosystem net primary productivity, and (2) energy use of individuals, as influenced by body mass and ambient temperature. Using data from the North American Christmas Bird Count, we find that total

Timothy D. Meehan; Walter Jetz; James H. Brown

2004-01-01

338

Winter peak of respiratory syncytial virus in Islamabad.  

PubMed

A study was carried out on 391 cases of bronchiolitis and pneumonia from different paediatric units in Rawalpindi/Islamabad, Pakistan. A clear winter spike of respiratory syncytial virus (RSV) was noted. It was found that there was a substantial increase of 30-50% in the positivity of RSV from December to February. PMID:15712541

Tariq, Waheed-Uz-Zaman; Waqar, Talal; Ali, Salman; Ghani, Eijaz

2005-01-01

339

EVAPOTRANSPIRATION OF DEFICIT IRRIGATED SORGHUM AND WINTER WHEAT  

Microsoft Academic Search

Deficit irrigation commonly is used in regions with reduced or limited irrigation capacity to increase water use efficiency (WUE). This research measured winter wheat (Triticum aestivum L.) and sorghum (Sorghum bicolor L. Moench) water use (ET) and yields so WUE could be determined. Two precision weighing lysimeters were used to accurately measure the crop ET from fully irrigated (FULL) fields

T. A. Howell; J. A. Tolk; S. R. Evett; K. S. Copeland; D. A. Dusek

340

Varietal Trials Results Wheat, Hard Red Winter  

E-print Network

Varietal Trials Results Wheat, Hard Red Winter 47 Winter wheat varieties were compared in trial plots at Crookston, Lamberton, Roseau and St. Paul. Wheat varieties were grown in replicated plots. These winter wheat trials are not designed for crop (species) compar- isons because the various crops are grown

Thomas, David D.

341

Leadership in American Indian Communities: Winter Lessons  

ERIC Educational Resources Information Center

Winter lessons, or stories told in the winter, were one of the ways in which tribal elders instructed and directed young men and women in the proper ways to assume leadership responsibilities. Winter lessons stressed the appropriate relationship between the leader and the community. The intent was to remember the power and purpose of that…

Metoyer, Cheryl A.

2010-01-01

342

Daily movements of female mallards wintering in Southwestern Louisiana  

USGS Publications Warehouse

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.

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

2011-01-01

343

Winter fuels report. Week ending, October 21, 1994  

SciTech Connect

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

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

1994-10-01

344

Night eating syndrome and winter seasonal affective disorder.  

PubMed

Night eating syndrome (NES) and winter seasonal affective disorder (SAD) share some features such as snacking for high-carbohydrate/high-fat food with increased weight, emotional distress, circadian disturbances, good response to serotoninergic antidepressants (SSRIs) and bright-light therapy. This study assessed the prevalence and socio-demographical and clinical correlates of the NES in a sample of 62 consecutive depressed outpatients with winter seasonal features (DSM-IV criteria). Depression was assessed with the 29 item-HDRS and Sigh-SAD version and with the 7-item depression subscale of the Hospital Anxiety and Depression scale. The prevalence of NES was low (4.8%). Patients suffering from NES were significantly older with a greater duration of the illness. NES was not related to depression and to Body Mass Index. NES and winter SAD are not overlapping disorders. PMID:16632073

Friedman, Serge; Even, Christian; Thuile, Jacques; Rouillon, Frédéric; Guelfi, Julien-Daniel

2006-07-01

345

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

PubMed

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. PMID:24577381

Teleg?ów, Aneta; D?browski, Zbigniew; Marchewka, Anna; Tyka, Aleksander; Krawczyk, Marcin; G?odzik, Jacek; Szygu?a, Zbigniew; Mleczko, Edward; Bilski, Jan; Tyka, Anna; Tabarowski, Zbigniew; Czepiel, Jacek; Filar-Mierzwa, Katarzyna

2014-01-01

346

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

USGS Publications Warehouse

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.

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

2006-01-01

347

Winter 2009 The Rural Partnership  

E-print Network

TEr 2009 CommunicationsTeam Writing,Editing BRADANDERSON andDesign ShEilAChAmpliN REBECCAENNiS KEll,(901)448-5558orTDD(901) 448-7382orlogontoourWebsiteatwww.utmem.edu. #12; Winter0093 CONTENTS NEWS BITES MEMPHIS for Dr. Wall CAMPUS PROGRESS · HEI Receives Final Touches · Le Builders Assist with Le Bonheur NEWS · Dr

Cui, Yan

348

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

PubMed

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

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

2013-12-22

349

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

PubMed Central

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

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

2013-01-01

350

Effect of canopy removal on snowpack quantity and quality, Fraser experimental forest, Colorado  

NASA Astrophysics Data System (ADS)

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 NH 4+ concentrations on the clearcut were lower and NO 3- higher than in the snowpack beneath the forested plots. Cumulative 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 (NO 3- and NH 4+) 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.

Stottlemyer, R.; Troendle, C. A.

2001-05-01

351

Winter Survival of Pratylenchus scribneri  

PubMed Central

Population densities of Pratylenchus scribneri in a Plainfield loamy sand soil were sampled from 1 October to 1 May for 4 years. From May to October of each year, the site was planted to Russet Burbank potato and Wis 4763 corn. Percentages of change in population densities of nematodes were computed on the basis of number of nematodes present on 1 October. The decline of P. scribneri between growing seasons was nonlinear, with most mortality occurring in the autumn before the soil froze. Winter survival, defined as the percentage of change in population densities from 1 October to 1 May the following year, ranged from 50 to 136% for nematodes in corn plots and from 15 to 86% for nematodes in potato plots. There was no difference in survival of nematodes of different life stages or among root and soil habitats. Winter survival of nematodes was density-dependent in 3 of 4 years in corn plots and in 1 of 4 years in potato plots. Although predators were present, their abundance was not correlated with the winter survival of nematodes. Cumulative and average snow cover was correlated with the survival of nematodes associated with corn but not with potato. No relationships between other climatic factors and survivorship were detected. PMID:19283113

MacGuidwin, A. E.; Forge, T. A.

1991-01-01

352

Effect of water on yield of winter wheat at different growth phases  

NASA Astrophysics Data System (ADS)

The characteristic of climate in North China is short of precipitation in winter and spring. Insufficient supply of water is a major factor affecting yield of winter wheat. The variation of yield caused by irrigation or drought at different stages is not alike. The relationship between them can be represented with water-yield reaction coefficient. Based on the experiment conducted in 2001 through 2004, yield of winter wheat has a marked positive correlation with precipitation at different stages after winter. The water-yield reaction coefficients increase with crop development, especially in turning green stage. The maximum occurs at head sprouting stage. Then it decreases slightly at milking stage. In order to raise water use efficiency of winter wheat, it is necessary to practice irrigation at elongating and head sprouting stages first and milking stage next.

Liu, Ronghua; Shen, Shuanghe; Zhu, Zixi; Fang, Wensong; Wang, Youhe; Xu, Pengpeng; Shi, Likui

2006-08-01

353

Winter Biological Processes Could Help Convert Arctic Tundra to Shrubland  

NSDL National Science Digital Library

This peer-reviewed article from BioScience investigates the change from tundra to shrubland in the arctic. In arctic Alaska, air temperatures have warmed 0.5 degrees Celsius (C) per decade for the past 30 years, with most of the warming coming in winter. Over the same period, shrub abundance has increased, perhaps a harbinger of a conversion of tundra to shrubland. Evidence suggests that winter biological processes are contributing to this conversion through a positive feedback that involves the snow-holding capacity of shrubs, the insulating properties of snow, a soil layer that has a high water content because it overlies nearly impermeable permafrost, and hardy microbes that can maintain metabolic activity at temperatures of −6C or lower. Increasing shrub abundance leads to deeper snow, which promotes higher winter soil temperatures, greater microbial activity, and more plant-available nitrogen. High levels of soil nitrogen favor shrub growth the following summer. With climate models predicting continued warming, large areas of tundra could become converted to shrubland, with winter processes like those described here possibly playing a critical role.

MATTHEW STURM, JOSH SCHIMEL, GARY MICHAELSON, JEFFREY M. WELKER, STEVEN F. OBERBAUER, GLEN E. LISTON, JACE FAHNESTOCK, and VLADIMIR E. ROMANOVSKY (;)

2005-01-01

354

Monitoring the global-scale winter anomaly of total electron contents using GPS data  

NASA Astrophysics Data System (ADS)

The winter anomaly phenomenon of Total Electron Contents (TEC) at latitudes 15°-60°N and 15°S-60°S is presented using GPS carrier-phase data obtained from GPS stations during 2002. The correlation between the [O/N2] ratio estimated using the NRLMSISE-00 atmospheric model and the TEC winter anomaly is also investigated. The numerical results show that the TEC winter anomaly in different regions of the world tends to be dominated by different factors. In North America, the TEC winter anomaly is strongly affected by the magnetospheric processes in high latitudes and the [O/N2] ratio. In the Euro-Africa and Russia-Asia regions, the TEC winter anomaly depends mainly on the [O/N2] ratio at the latitude band of 30°-60°N, and the extent of the TEC winter anomaly gradually decreases from 60°N to 30°N. The extent of the TEC winter anomaly increases at the latitude band of 15°-30°N due to the influence of the meridional neutral wind and the seasonal changes of the subsolar point. However, the TEC winter anomaly was not observed in southern hemisphere in 2002. The TEC equinoctial asymmetries in the northern and southern hemisphere are also presented using GPS TEC values collected in March and September 2002.

Huo, X. L.; Yuan, Y. B.; Ou, J. K.; Zhang, K. F.; Bailey, G. J.

2009-08-01

355

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

PubMed Central

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

Schröder, Arne

2013-01-01

356

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

PubMed

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

Princé, Karine; Zuckerberg, Benjamin

2015-02-01

357

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

PubMed

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

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

2009-11-01

358

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

NASA Astrophysics Data System (ADS)

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 that were more frequently used to grow corn had a higher potential for nitrate leaching and export to the waterways. This study supports the effective implement of winter cover crop programs, in part by helping to target critical pollution source areas for winter cover crop implementation.

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

2013-11-01

359

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

USGS Publications Warehouse

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 that were more frequently used to grow corn had a higher potential for nitrate leaching and export to the waterways. This study supports the effective implement of winter cover crop programs, in part by helping to target critical pollution source areas for winter cover crop implementation.

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

2013-01-01

360

Comparison of generalist predators in winter-flooded and conventionally managed rice paddies and identification of their limiting factors.  

PubMed

Winter-flooding of rice paddies without the application of agricultural chemicals is attracting attention as a new agricultural method for enhancing the habitat conditions of wintering waterfowl in rice paddy ecosystems throughout Japan and east Asia. Conditions in these paddies are expected to result in restoration of not only the winter habitats of waterfowl but also those of other taxonomic groups during the rice growing season. In this study, we tested whether the diversity of summer spiders--ubiquitous predators in rice paddies--was higher in the winter-flooded paddies than in the conventional ones by conducting field measurements in 31 winter-flooded and 7 conventional paddies. Limiting factors of spiders in the winter-flooded paddies were then examined. Results revealed that both the density and species richness of spiders were significantly higher in the winter-flooded paddies than in the conventional ones both before and after the insecticide application against pecky rice bug Stenotus rubrovittatus (Matsumura)(Hemiptera: Miridae) to conventional paddies. In addition, spider density and species richness in the winter-flooded paddies correlated with the availability of two prey groups--chironomids and other nematocera. These findings suggest that in the winter-flooded paddies the diversity of generalist predators is higher than in the conventional ones during the rice-growing season and that the combination of management at both the landscape and field level is likely more effective for increasing spider abundance in winter-flooded paddies. PMID:25140294

Takada, Mayura B; Takagi, Shun; Iwabuchi, Shigeki; Mineta, Takuya; Washitani, Izumi

2014-01-01

361

Effects of climate on mid-winter ice jams  

NASA Astrophysics Data System (ADS)

The breakup of ice in Canadian rivers and the ensuing ice jams have a multitude of socio-economic impacts. Equally important, but not as well understood, is the strong relationship between the breakup event and the aquatic ecosystem in terms of both habitat and life cycle. Because breakup processes are highly sensitive to weather conditions, there is concern over the potential effects of changing climatic patterns on the ice-jam regime and thus on the stream ecology and local economy. Though breakup commonly occurs in the spring, it is occasionally triggered by mid-winter thaws, which are typical of the more temperate regions of Canada. Mid-winter jams can be more destructive than spring ones and may also have repercussions on the spring event. Current knowledge suggests that small perturbations in winter temperature can produce major changes in the incidence of breakup and ice jams, by altering snowstorms into rainfall events. This expectation is confirmed by a hydroclimatic analysis of field observations and historical data on the upper reach of the Saint John River, which forms the boundary between New Brunswick, Canada and Maine, USA. A slight warming in the past 80 years has been accompanied by a considerable increase in the occurrence of mild winter days, thus contributing to increasing rainfall amounts. This results in augmented flows during the winter, which are lately becoming capable of effecting breakup of the river-ice cover. Implications for future trends in the ice regime of the Saint John River and of other Canadian rivers are discussed.

Beltaos, Spyros

2002-03-01

362

Wintering Steer Calves at the Spur Station.  

E-print Network

trials, in most instances, were based on 3 or more years of work. Roughages used in wintering steer calves weighing 325 to 400 pounds were wheat pasture, natire grass, sorghum silage, bundle feeds and stalk fields. Protein supplements were fed... with sorghum sil- age and chopped bundles in the drylot,, and on native grass and stalk fields. Calves wintered on wheat pasture in 10 of the 14 years made the second highest average winter gain, third highest summer gain and the highest total winter...

Jones, J. H.; Fisher, C. E.; Marion, P. T.

1956-01-01

363

Winter warming from large volcanic eruptions  

SciTech Connect

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.

Robock, A.; Mao, J.

1992-01-01

364

Mercury in breeding and wintering Nelson's Sparrows (Ammodramus nelsoni).  

PubMed

The objective of this study was to increase our understanding of Hg exposure in birds with obligate ties to coastal salt marsh and inland wetland systems. Many species filling such niches are of conservation concern because of reduced size and quality of vital habitats. We used Nelson's Sparrow (Ammodramus nelsoni) as an indicator of regional mercury (Hg) availability in its breeding and wintering salt marsh and wetland habitats. Blood, breast feathers and the first primary feather were sampled from Nelson's Sparrows wintering in North Carolina coastal salt marshes and breeding in wetland systems in North Dakota (A. n. nelsoni) and Ontario, Canada (A. n. alterus). Wintering Nelson's Sparrow breast feathers contained 3.0 times as much Hg as birds breeding in North Dakota and 2.4 times as much Hg as those breeding in Ontario. Breeding Nelson's Sparrows in North Dakota exhibited blood Hg levels 4.9 times as high as those from birds breeding along James Bay and 7.6 times as high as those wintering in North Carolina. These results provide significant insight on the timing of molt in this species as well as how Hg exposure varies regionally and seasonally for these birds. Further, our results provide a better understanding of how and where Hg exposure may be a threat to Nelson's Sparrows and other birds with obligate ties to aquatic systems. PMID:21082242

Winder, V L; Emslie, S D

2011-01-01

365

Impacts of winter storms on air-sea gas exchange  

NASA Astrophysics Data System (ADS)

The objective of this study is to investigate air-sea gas exchange during winter storms, using field measurements from Ocean Station Papa in the Northeast Pacific (50°N, 145°W). We show that increasing gas transfer rates are coincident with increasing winds and deepening depth of bubble penetration, and that this process depends on sea state. Wave-breaking is shown to be an important factor in the gas transfer velocity during the peaks of the storms, increasing the flux rates by up to 20%. Gas transfer rates and concentrations can exhibit asymmetry, reflecting a sudden increase with the onset of a storm, and gradual recovery stages.

Zhang, Weiqing; Perrie, Will; Vagle, Svein

2006-07-01

366

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

PubMed Central

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

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

2012-01-01

367

Vol. 4, No. 1 Winter 200506Vol. 4, No. 1 Winter 200506 Informatics  

E-print Network

Vol. 4, No. 1 · Winter 2005­06Vol. 4, No. 1 · Winter 2005­06 LEAD Informatics Researchers Take the in Hurricane Prediction LEAD Informatics Researchers Take the in Hurricane Prediction #12;Vol. 4, No. 1 WINTER with the School of Informatics, and is mailed to all alumni of the School of Informatics. For information about

Zhou, Yaoqi

368

The Influence of Habitat Features on Selection and Use of a Winter Refuge by Manatees (Trichechus manatus latirostris) in Charlotte Harbor, Florida.  

E-print Network

??Investigating alternate winter refuges for Florida manatees is increasingly important as sustained warm-water discharges from industrial and some natural sites becomes more uncertain. This study… (more)

Barton, Sheri L.

2006-01-01

369

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

NASA Astrophysics Data System (ADS)

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

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

2006-05-01

370

TRUE WINTER RANGE OF THE VEERY (CATHARUS FUSCESCENS): LESSONS FOR DETERMINING WINTER RANGES OF SPECIES THAT WINTER IN THE TROPICS  

Microsoft Academic Search

Most recent references describe the winter range of the Veery (Catharus fus- cescens) as including an extensive area from northern Colombia, Venezuela, and Guyana south to south-central Brazil. Analysis of seasonal distribution of specimen records in South America, however, shows that 91 of 105 specimens were taken during spring and fall, not winter; the remaining 14, taken from 2 December

J. V. Remsen Jr.

2001-01-01

371

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

372

Effects of waterlogging and drought on winter wheat and winter barley grown on a clay and a sandy loam soil  

Microsoft Academic Search

The effects of winter waterlogging and a subsequent drought on the growth of winter barley and winter wheat have been examined. We used lysimeters containing soil monoliths with facilities to control the water table and a mobile shelter to control rainfall. Winter wheat was grown on a clay and on a sandy loam, but winter barley only on the clay

R. Q. Cannell; R. K. Belford; K. Gales; R. J. Thomson; C. P. WEB-S-TE-P

1984-01-01

373

An analysis of US propane markets, winter 1996-1997  

SciTech Connect

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

NONE

1997-06-01

374

HISTORICAL CHANGES IN THE ABUNDANCE AND DISTRIBUTION OF THE AMERICAN AVOCET AT THE NORTHERN LIMIT OF ITS WINTER RANGE  

Microsoft Academic Search

Humboldt Bay, California, is the northern limit of the winter distribution of the American Avocet (Recurvirostra americana) on the Pacific coast. After the first record in 1935, avocets were uncommon (17 observations) until the early 1960s, when a wintering population of <100 birds became established in North (Arcata) Bay. Numbers increased to approximately 1000 by the early 1990s but have

MARK A. COLWELL; TAMAR DANUFSKY; RYAN L. MATHIS

2001-01-01

375

Cadmium in Soil and Winter Wheat Grain in Southern Sweden: I. Factors Influencing Cd Levels in Soils and Grain  

Microsoft Academic Search

The guideline level for Cd contents in cereals of 100 ?g kg proposed by the Codex Committee on Cereals, Pulses and Legumes has increased concern regarding Cd levels in Swedish winter wheat. In this study, Cd levels in soil and grain and factors influencing these variables were investigated in Skåne, the southernmost province in Sweden. In 1992, soils and winter

Jan. E. Eriksson; Mats Söderström

1996-01-01

376

Social status does not affect resting metabolic rate in wintering dark-eyed junco (Junco hyemalis).  

PubMed

Studies of wintering birds have demonstrated a correlation between social rank and energy expenditures. It is assumed that dominance is energetically costly because of increased activity, possibly caused by elevated androgen levels. As winter acclimatization leads to an increase in metabolic rate, maintaining dominance status in a cold climate can be a substantial challenge. We measured resting metabolic rates in dominant and subordinate dark-eyed juncos (Junco hyemalis) living in small groups in a controlled winter environment. We found no significant effect of social rank when controlling for body size. It has been shown previously that high testosterone levels during the nonbreeding season can lead to higher body conductance, fat loss, and higher nocturnal body temperature. A hypothesis explaining our result is that for juncos it is preferable to maintain low androgen levels during winter and to maintain social rank using a mechanism other than higher agonistic activity. PMID:10801401

Vézina, F; Thomas, D W

2000-01-01

377

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

PubMed

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

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

2009-08-01

378

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

USGS Publications Warehouse

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

Hestbeck, J.B.

1998-01-01

379

PLCO News, Fall/Winter 1998  

Cancer.gov

PLCO News, Fall/Winter 1998 Volume 1, Number 2 ----- Fall/Winter 1998 TABLE OF CONTENTS Notes from theNCI's PLCO Project Office Meet John GohaganMeet Phil Prorok From Lab to Life Possible prostate cancer prevention with vitamin E and selenium

380

Nuclear Winter: Scientists in the Political Arena  

NASA Astrophysics Data System (ADS)

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

Badash, Lawrence

2001-03-01

381

Hatchling Turtles Survive Freezing during Winter Hibernation  

Microsoft Academic Search

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

Kenneth B. Storey; Janet M. Storey; Stephen P. J. Brooks; Thomas A. Churchill; Ronald J. Brooks

1988-01-01

382

Animals in Winter. Young Discovery Library Series.  

ERIC Educational Resources Information Center

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…

de Sairigne, Catherine

383

NEW INTERNSHIP FOR WINTER Interactive Ecology  

E-print Network

NEW INTERNSHIP FOR WINTER Interactive Ecology UC Santa Cruz Arboretum Internship Agency Sponsor, back pack tracker, GPS, google earth, etc). The Interactive Ecology internship will also explore, more into areas of special interest. For more information regarding Winter Quarter, 2015 contact: Brett Hall, (831

Wilmers, Chris

384

CMPUT 631 Winter 2013 Robotics: Visual Navigation  

E-print Network

Navigation: State-of-the-Art · DARPA Grand Challenge 2004/2005 · DARPA Urban Challenge (2008) · Cummins: "Robots that fly" (GRASP Lab, 2011) · Big dog and Petman (Boston Dynamics, 2008, 2010) · DARPA Robotics sets ­Credit for creativity CMPUT 631 Winter 2013 CMPUT 631 Winter 2013 DARPA Grand Challenge 2004

Zhang, Hong

385

PLCO News, Fall/Winter 1998  

Cancer.gov

PLCO News, Fall/Winter 1998 Volume 1, Number 2 ----- Fall/Winter 1998 Trial Update Enrollment goal: 148,000 Total enrollment (as of September 30, 1998): 111,515 Men enrolled: 58,283 Women enrolled: 53,232 Number of people enrolled

386

PLCO News, Fall/Winter 1998  

Cancer.gov

PLCO News, Fall/Winter 1998 Volume 1, Number 2 ----- Fall/Winter 1998 Cancer Information Center If you have a question about cancer you can call and speak with a trained specialist at NCI's Cancer Information Service (CIS). The CIS operates a toll-free,

387

Winter Icing and Storms Project (WISP)  

Microsoft Academic Search

Field studies in support of the Winter Icing and Storms Project (WISP) were conducted in the Colorado Front Range area from 1 February to 31 March 1990(WISP90) and from 15 January to 5 April 1991 (WISP91). The main goals of the project are to study the processes leading to the formation and depletion of supercooled liquid water in winter storms

Roy Rasmussen; Marcia Politovich; John Marwitz; Wayne Sand; John McGinley; John Smart; Roger Pielke; Steve Rutledge; Doug Wesley; Greg Stossmeister; Ben Bernstein; Kim Elmore; Nick Powell; Ed Westwater; B. Boba Stankov; Don Burrows

1992-01-01

388

Excess Winter Mortality and Cold Temperatures in a Subtropical City, Guangzhou, China  

PubMed Central

Background A significant increase in mortality was observed during cold winters in many temperate regions. However, there is a lack of evidence from tropical and subtropical regions, and the influence of ambient temperatures on seasonal variation of mortality was not well documented. Methods This study included 213,737 registered deaths from January 2003 to December 2011 in Guangzhou, a subtropical city in Southern China. Excess winter mortality was calculated by the excess percentage of monthly mortality in winters over that of non-winter months. A generalized linear model with a quasi-Poisson distribution was applied to analyze the association between monthly mean temperature and mortality, after controlling for other meteorological measures and air pollution. Results The mortality rate in the winter was 26% higher than the average rate in other seasons. On average, there were 1,848 excess winter deaths annually, with around half (52%) from cardiovascular diseases and a quarter (24%) from respiratory diseases. Excess winter mortality was higher in the elderly, females and those with low education level than the young, males and those with high education level, respectively. A much larger winter increase was observed in out-of-hospital mortality compared to in-hospital mortality (45% vs. 17%). We found a significant negative correlation of annual excess winter mortality with average winter temperature (rs=-0.738, P=0.037), but not with air pollution levels. A 1 °C decrease in monthly mean temperature was associated with an increase of 1.38% (95%CI:0.34%-2.40%) and 0.88% (95%CI:0.11%-1.64%) in monthly mortality at lags of 0-1 month, respectively. Conclusion Similar to temperate regions, a subtropical city Guangzhou showed a clear seasonal pattern in mortality, with a sharper spike in winter. Our results highlight the role of cold temperature on the winter mortality even in warm climate. Precautionary measures should be strengthened to mitigate cold-related mortality for people living in warm climate. PMID:24116214

Yang, Jun; Chau, Patsy Yuen-Kwan; Yang, Lin; Chen, Ping-Yan; Wong, Chit-Ming

2013-01-01

389

Number of waterfowl wintering in Moscow (1985-2004): dependence on climate conditions  

Microsoft Academic Search

Over nineteen years (1985-2004), wintering waterfowl were censused at all Moscow water bodies during the day in the middle of January, thanks to the participation of volunteers under the leadership of the Russian Bird Conservation Union (RBCU). The number of species gradually increased in the study period (r=0.86; p<0.01; n=20). Trends for the four main wintering species (Mallard Anas platyrhynchos,

Ksenya V. Avilova

390

Are summit metabolism and thermogenic endurance correlated in winter-acclimatized passerine birds?  

Microsoft Academic Search

Small birds exhibiting marked winter improvement of cold tolerance also show elevated summit metabolic rates (maximum cold-induced metabolic rate) in winter relative to summer. However, relatively large increases in cold tolerance can occur with only minor increments of maximum cold-induced metabolic rate and geographic variation in cold tolerance is not always positively correlated with variation in maximum cold-induced metabolic rate.

David L. Swanson

2001-01-01

391

Multistate proteomics analysis reveals novel strategies used by a hibernator to precondition the heart and conserve ATP for winter heterothermy  

PubMed Central

The hibernator's heart functions continuously and avoids damage across the wide temperature range of winter heterothermy. To define the molecular basis of this phenotype, we quantified proteomic changes in the 13-lined ground squirrel heart among eight distinct physiological states encompassing the hibernator's year. Unsupervised clustering revealed a prominent seasonal separation between the summer homeotherms and winter heterotherms, whereas within-season state separation was limited. Further, animals torpid in the fall were intermediate to summer and winter, consistent with the transitional nature of this phase. A seasonal analysis revealed that the relative abundances of protein spots were mainly winter-increased. The winter-elevated proteins were involved in fatty acid catabolism and protein folding, whereas the winter-depleted proteins included those that degrade branched-chain amino acids. To identify further state-dependent changes, protein spots were re-evaluated with respect to specific physiological state, confirming the predominance of seasonal differences. Additionally, chaperone and heat shock proteins increased in winter, including HSPA4, HSPB6, and HSP90AB1, which have known roles in protecting against ischemia-reperfusion injury and apoptosis. The most significant and greatest fold change observed was a disappearance of phospho-cofilin 2 at low body temperature, likely a strategy to preserve ATP. The robust summer-to-winter seasonal proteomic shift implies that a winter-protected state is orchestrated before prolonged torpor ensues. Additionally, the general preservation of the proteome during winter hibernation and an increase of stress response proteins, together with dephosphorylation of cofilin 2, highlight the importance of ATP-conserving mechanisms for winter cardioprotection. PMID:21914784

Grabek, Katharine R.; Karimpour-Fard, Anis; Epperson, L. Elaine; Hindle, Allyson; Hunter, Lawrence E.

2011-01-01

392

Development of a snowfall–snowmelt routine for mountainous terrain for the soil water assessment tool (SWAT)  

Microsoft Academic Search

The soil water assessment tool (SWAT) is a hydrologic model originally developed to evaluate water resources in large agricultural basins. SWAT was not designed to model heterogeneous mountain basins typical of the western United States, and as a result, has performed poorly when applied to mountainous locations. The intent of this study was to increase the versatility of SWAT by

T. A. Fontaine; T. S. Cruickshank; J. G. Arnold; R. H. Hotchkiss

2002-01-01

393

El Niño-Southern Oscillation Impacts on Winter Vegetable Production in Florida*.  

NASA Astrophysics Data System (ADS)

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.

Hansen, James W.; Jones, James W.; Kiker, Clyde F.; Hodges, Alan W.

1999-01-01

394

Connection between autumn Sea Surface Temperature and winter precipitation in the Iberian Peninsula  

NASA Astrophysics Data System (ADS)

The oceanic influence on winter precipitation in the Iberian Peninsula has been evidenced in numerous scientific papers. Large-scale forecasting models generally use variables such as Sea Surface Temperature (SST), soil moisture and ice cover, but they are not very accurate yet. Using observational data, this paper analyzes the influence of North Atlantic and Mediterranean SST on winter precipitation in the Iberian Peninsula between October 1951 and September 2011. First, trends of both data sets have been calculated to study their behavior during the past six decades, showing an overall increase of SST and a substantial decrease in winter precipitation in the Iberian Peninsula, except in eastern and south-eastern regions. Then, connection patterns between autumn Sea Surface Temperature Anomalies and winter precipitation have been studied to identify ocean regions that may be used as potential predictors of winter precipitation. After applying a Principal Component Analysis to cluster the information provided by the 1431 measuring points of a SST grid with a small number of variables, the Principal Components extracted were introduced into a Multiple Linear Regression algorithm in order to obtain an estimation of winter precipitation in each river basin. The validation process has shown that the algorithm explains nearly 50% of inter-annual variability of winter precipitation in the basins of the Iberian Peninsula with a strongly oceanic influence; this percentage is somewhat lower in the Mediterranean regions.

Fernández-González, Sergio; Pereira, Susana C.; Castro, Amaya; Rocha, Alfredo; Fraile, Roberto

2014-10-01

395

Changes in the structure of the rhizosphere complex of actinomycetes in the ontogenesis of winter rye  

NASA Astrophysics Data System (ADS)

Changes in the taxonomic structure of actinomycetes in the rhizosphere of winter rye ( Secale cereale L.) growing on acid soddy-podzolic soil were studied. During the first stages of ontogenesis of winter rye, the rhizosphere complex of mycelial prokaryotes was characterized by a relatively level generic structure (with respect to the indices of abundance and frequency of particular genera), low values of the species diversity, and low domination frequency of the species from the Streptomyces genus. The numbers and species diversity of the streptomycetes increased during the further growth of the winter rye, so that streptomycetes became a dominant group in the complex of the rhizosphere actinomycetes. According to the two-way ANOVA, the population density of the Micromonospora and the Streptosporangium genera in the rhizosphere was mainly dictated by the winter rye variety, whereas the population density of the streptomycetes depended on the particular stage of the winter rye development. The differences between the actinomycetal complexes characteristic of different varieties of winter rye at the early stages of its development was leveled by the end of the winter rye growth.

Shirokikh, I. G.; Merzaeva, O. V.; Zenova, G. M.

2006-06-01

396

A metagenomic assessment of winter and summer bacterioplankton from Antarctica Peninsula coastal surface waters  

PubMed Central

Antarctic surface oceans are well-studied during summer when irradiance levels are high, sea ice is melting and primary productivity is at a maximum. Coincident with this timing, the bacterioplankton respond with significant increases in secondary productivity. Little is known about bacterioplankton in winter when darkness and sea-ice cover inhibit photoautotrophic primary production. We report here an environmental genomic and small subunit ribosomal RNA (SSU rRNA) analysis of winter and summer Antarctic Peninsula coastal seawater bacterioplankton. Intense inter-seasonal differences were reflected through shifts in community composition and functional capacities encoded in winter and summer environmental genomes with significantly higher phylogenetic and functional diversity in winter. In general, inferred metabolisms of summer bacterioplankton were characterized by chemoheterotrophy, photoheterotrophy and aerobic anoxygenic photosynthesis while the winter community included the capacity for bacterial and archaeal chemolithoautotrophy. Chemolithoautotrophic pathways were dominant in winter and were similar to those recently reported in global ‘dark ocean' mesopelagic waters. If chemolithoautotrophy is widespread in the Southern Ocean in winter, this process may be a previously unaccounted carbon sink and may help account for the unexplained anomalies in surface inorganic nitrogen content. PMID:22534611

Grzymski, Joseph J; Riesenfeld, Christian S; Williams, Timothy J; Dussaq, Alex M; Ducklow, Hugh; Erickson, Matthew; Cavicchioli, Ricardo; Murray, Alison E

2012-01-01

397

Winter Olympics Physics and Biomechanics  

NSDL National Science Digital Library

Many Winter Olympic sports are greatly dependent on technique, engineering, and/or gravity. For example, during luge, while gravity is accelerating the sled up to 80 mph down the track, the slider must use good technique to steer the sled and minimize air resistance. To excel in these type of sports, it is helpful to have a full appreciation of physics and biomechanics. Physics is a broad field which includes mechanics, electricity, magnetism, optics, etc., and biomechanics is the study of the mechanics of living systems. In the module we will use the sports of luge and figure skating to teach you four basic mechanical concepts: linear kinematics, linear dynamics, projectile motion, and conservation of angular momentum. In addition, we have developed a glossary which defines and illustrates all the physics terminology you will need to complete this module.

398

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

PubMed

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. PMID:23630015

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

2013-09-01

399

Responses of the photosynthetic apparatus to winter conditions in broadleaved evergreen trees growing in warm temperate regions of Japan.  

PubMed

Photosynthetic characteristics of two broadleaved evergreen trees, Quercus myrsinaefolia and Machilus thunbergii, were compared in autumn and winter. The irradiance was similar in both seasons, but the air temperature was lower in winter. Under the winter conditions, net photosynthesis under natural sunlight (Anet) in both species dropped to 4 ?mol CO2 m(-2) s(-1), and the quantum yield of photosystem II (PSII) photochemistry in dark-adapted leaves (Fv/Fm) also dropped to 0.60. In both species the maximum carboxylation rates of Rubisco (Vcmax) decreased, and the amount of Rubisco increased in winter. A decline in chlorophyll (Chl) concentration and an increase in the Chl a/b ratio in winter resulted in a reduction in the size of the light-harvesting antennae. From measurements of Chl a fluorescence parameters, both the relative fraction and the energy flux rates of thermal dissipation through other non-photochemical processes were markedly elevated in winter. The results indicate that the photosynthetic apparatus in broadleaved evergreen species in warm temperate regions responds to winter through regulatory mechanisms involving the downregulation of light-harvesting and photosynthesis coupled with increased photoprotective thermal energy dissipation to minimize photodamage in winter. These mechanisms aid a quick restart of photosynthesis without the development of new leaves in the following spring. PMID:25500451

Tanaka, Chizuru; Nakano, Takashi; Yamazaki, Jun-Ya; Maruta, Emiko

2015-01-01

400

Recent variations of snow cover and snowfall in North America and their relation to precipitation and temperature variations  

Microsoft Academic Search

Contemporary large-scale changes in solid and total precipitation and satellite-derived snow cover were examined over the North American continent. Annual snow cover extent over the last 19 years decreased up to 6 [times] 10[sup 5] km[sub 2] relative to a 0.93[degrees]C (0.33[degrees]C) increase in North American (Northern Hemisphere) temperature. A strong correlation exists between snow cover and temperature where up

Thomas R. Karl; Pavel Ya. Groisman; Richard W. Knight

1993-01-01

401

Red spruce decline---Winter injury and air pollutants  

SciTech Connect

There has been a widespread decline in growth of red spruce (Picea rubens Sarg.) since 1960 in the eastern United States. There is evidence that this decline is at least partly attributable to age- and density-related growth patterns, particularly at lower elevations. Mortality has been severe at high elevation sites where similar episodes have occasionally occurred in the last 100 years. At these sites, periods of low growth preceding 1960 were related to periods with warm late summers and cold early winters. Since 1960, this relationship no longer holds, although there is an association with unusual deviations from mean temperatures. There are field reports that one of the main causes of reduced growth and mortality is apical dieback induced by severe winter conditions. Preliminary observations suggest that high elevation red spruce may not be sufficiently hardened to tolerate low autumn temperatures. However, appearance of injury in the spring, association of injury with wind exposure and correlation of provenance susceptibility with cuticular transpiration rates, including the importance of desiccation injury. Sensitivity to both types of winter injury may be increased by air pollutants (particularly ozone and less probably, acid mist or excess nitrogen deposition). Nutrient deficiency (particularly magnesium and to a lesser extent potassium) may also increase cold sensitivity. The nature and extent of these interactions are being actively researched for red spruce. 48 refs.

Roberts, T.M. (Central Electricity Research Labs., Leatherhead (UK))

1989-10-01

402

Climate warming will not decrease winter mortality  

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

403

Predictability of northern Adriatic winter conditions  

NASA Astrophysics Data System (ADS)

Presented results indicate that a long-term (several months ahead) forecast of the winter northern Adriatic conditions is possible and that it can be based on the analysis of meteorological conditions and geostrophic circulation fields of the previous autumn. Using 1981-2007 February data we show that in winters of the type A, salinity in the northern Adriatic is lower and production of phytoplankton higher than in the B type winters. This indicates that the impact of the Po River waters on the northern Adriatic is more pronounced during the A type winters. The two types, A and B, have already been identified on the basis of the bottom density differences between eastern and western part of the northern Adriatic but more precise definition is given here. Based on the data collected during hydrographic cruises in 2000 (type B conditions) and 2001 (type A conditions), we found that the two winters differed in geostrophic circulation patterns as well. Eastward of the Po River delta there was a large cyclonic gyre in 2000 and a large anticyclonic gyre in 2001. Circulation patterns were highly dependent on autumn conditions, with bottom density changes as the most likely triggering cause. Strong surface heat losses and many bora episodes preceded the winter of 2000, while moderate cooling and sirocco events preceded the winter of 2001.

Supi?, Nastjenjka; Kraus, Romina; Kuzmi?, Milivoj; Paschini, Elio; Precali, Robert; Russo, Aniello; Vilibi?, Ivica

2012-02-01

404

Do wintering Harlequin Ducks forage nocturnally at high latitudes?  

USGS Publications Warehouse

We monitored radio-tagged Harlequin Ducks (Histrionicus histrionicus) to determine whether nocturnal feeding was part of their foraging strategy during winter in south-central Alaska. Despite attributes of our study site (low ambient temperatures, harsh weather, short day length) and study species (small body size, high daytime foraging rates) that would be expected to favor nocturnal foraging, we found no evidence of nocturnal dive-feeding. Signals from eight radio-tagged Harlequin Ducks never exhibited signal loss due to diving during a total of 780 minutes of nocturnal monitoring. In contrast, the same eight birds exhibited signal loss during 62 ?? 7% (SE) of 5-minute diurnal monitoring periods (total of 365 minutes of monitoring). Our results suggest that Harlequin Ducks in south-central Alaska face a stringent time constraint on daytime foraging during midwinter. Harlequin Ducks wintering at high latitudes, therefore, may be particularly sensitive to factors that increase foraging requirements or decrease foraging efficiency.

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

2005-01-01

405

Nutrient content of some winter grouse foods  

USGS Publications Warehouse

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.

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

1946-01-01

406

Role of roots in winter water relations of Engelmann spruce saplings.  

PubMed

Roots play a role in maintaining foliar water balance in subalpine conifer saplings during winter. We used deuterium-labeled water to demonstrate that roots of Engelmann spruce (Picea engelmannii Parry) take up water during the late-winter-early spring period. Based on a root severing experiment, we conclude that small, snow-covered saplings were largely dependent on root water uptake to meet winter transpiration needs, whereas larger saplings relied more on water stored in stem sapwood. Both water uptake and water stored in roots appeared to be critical for the survival of saplings exposed above the snowpack during the late-winter-early spring period, when sap reserves were insufficient to meet increasing transpirational demands. PMID:10562407

Boyce; Lucero

1999-11-01

407

Rapid climate driven shifts in wintering distributions of three common waterbird species.  

PubMed

Climate change is predicted to cause changes in species distributions and several studies report margin range shifts in some species. However, the reported changes rarely concern a species' entire distribution and are not always linked to climate change. Here, we demonstrate strong north-eastwards shifts in the centres of gravity of the entire wintering range of three common waterbird species along the North-West Europe flyway during the past three decades. These shifts correlate with an increase of 3.8 °C in early winter temperature in the north-eastern part of the wintering areas, where bird abundance increased exponentially, corresponding with decreases in abundance at the south-western margin of the wintering ranges. This confirms the need to re-evaluate conservation site safeguard networks and associated biodiversity monitoring along the flyway, as new important wintering areas are established further north and east, and highlights the general urgency of conservation planning in a changing world. Range shifts in wintering waterbirds may also affect hunting pressure, which may alter bag sizes and lead to population-level consequences. PMID:23509023

Lehikoinen, Aleksi; Jaatinen, Kim; Vähätalo, Anssi V; Clausen, Preben; Crowe, Olivia; Deceuninck, Bernard; Hearn, Richard; Holt, Chas A; Hornman, Menno; Keller, Verena; Nilsson, Leif; Langendoen, Tom; Tománková, Irena; Wahl, Johannes; Fox, Anthony D

2013-07-01

408

Winter weather versus group thermoregulation: what determines survival in hibernating mammals?  

PubMed

For socially hibernating mammals, the effectiveness of huddling as a means of energy conservation should increase with group size. However, group size has only been linked to increased survival in a few hibernating species, and the relative importance of social structure versus winter conditions during hibernation remains uncertain. We studied the influence of winter weather conditions, social group composition, age-structure, and other environmental factors and individual attributes on the overwinter survival of hoary marmots (Marmota caligata) in the Yukon Territory, Canada. Juvenile hoary marmot survival was negatively correlated with the mean winter (November to May) Pacific Decadal Oscillation (PDO) index. Survival in older age-classes was negatively correlated with PDO lagged by 1 year. Social group size and structure were weakly correlated with survival in comparison to PDO. The relationship between winter PDO and survival was most likely due to the importance of snowpack as insulation during hibernation. The apparent response of hoary marmots to changing winter conditions contrasted sharply with those of other marmot species and other mammalian alpine herbivores. In conclusion, the severity of winter weather may constrain the effectiveness of group thermoregulation in socially hibernating mammals. PMID:23456241

Patil, V P; Morrison, S F; Karels, T J; Hik, D S

2013-09-01

409

Climate Change Impacts on Winter and Spring Runoff and Recharge in Wisconsin  

NASA Astrophysics Data System (ADS)

Our research seeks to quantify the impacts of warming winter temperatures and increased winter precipitation on water resources in Wisconsin. We are currently working to calibrate a Precipitation-Runoff Modeling System (PRMS) model of the Black Earth Creek Watershed, and will be using a newly-created frost module to examine the impacts of warming winter temperatures on winter and spring infiltration. As a class 1 trout stream, Black Earth Creek is of particular interest as a sensitive and economically important natural resource. Research carried out over 2010 utilized a one-dimensional soil model (Simultaneous Heat and Water, or SHAW) that simulates heat and water fluxes as well as frost processes. This model was driven by climate data obtained from a set of statistically-downscaled and de-biased General Circulation Model (GCM) data for historic and projected future for the years 2046-2065 and 2081-2100 under the SRES A1B emissions scenario. This research suggested that warming temperatures and reduced snow cover, along with a projected increase in winter precipitation, would lead to decreased soil frost formation and a commensurate increase in winter and spring infiltration and recharge. The one-dimensional structure of the model, however, made it difficult to calibrate at the landscape scale, as it is fundamentally unable to replicate the complex spatial processes that are critically important to hydrologic response. We hope that the PRMS model, driven with the same modeled climatic data, will be able to confirm the results of our SHAW modeling; namely that winter and spring recharge will increase significantly in a warming climate. Such an increase in recharge could have profound impacts on Wisconsin fisheries, agriculture, and development.

Murdock, E. A.; Potter, K. W.

2011-12-01

410

Variability of Winter Air Temperature in Mid-Latitude Europe  

NASA Technical Reports Server (NTRS)

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 cover and precipitable water are from the National Centers for Environmental Prediction (NCEP) Reanalysis.

Otterman, J.; Ardizzone, J.; Atlas, R.; Bungato, D.; Cierniewski, J.; Jusem, J. C.; Przybylak, R.; Schubert, S.; Starr, D.; Walczewski, J.

2002-01-01

411

Analysis of spatial and yearly variation in winter survival of winter wheat  

Microsoft Academic Search

Four years of winter survival data for winter wheat (Triticum aestivum L.) were collected on a loam soil located on the Central Experimental Farm at Ottawa, Ontario (45 23?N, 75 43?W). The site\\u000a was low-lying and subject to frequent winter flooding and ice sheet formation. It appeared level although there was microtopographic\\u000a variation with a range in elevation of approximately

H. N. Hayhoe; C. J. Andrews

1999-01-01

412

Probabilistic Weather Forecasting for Winter Road Maintenance  

E-print Network

Probabilistic Weather Forecasting for Winter Road Maintenance Veronica J. Berrocal, Adrian E are needed. Currently, anti-icing decisions are usually based on deterministic weather forecasts. However. Starting with deterministic numerical weather predictions, they produce a joint predictive probability dis

Washington at Seattle, University of

413

Mojave sandy desert habitat in Winter (February)  

NSDL National Science Digital Library

By winter in non-drought years, the Mojave has received several inches of rain and healthy vegetation will begin to break ground by February. However, during drought years, vegetation will not experience its rapid growth season until spring.

Katie Hale (California State University, Fullerton; Student, Biological Sciences)

2007-01-06

414

AMAT/PMAT 4282 { Winter 2001 Cryptography  

E-print Network

AMAT/PMAT 4282 { Winter 2001 Cryptography Instructor #15; Name: Dr. David Pike #15; OÃ?ce: Henrietta Number Theory) and a computing course (AMAT 2120 or CS 2710 or CS 2602). #15; Textbook: \\Cryptography

deYoung, Brad

415

Severe Weather 101: Winter Weather Basics  

MedlinePLUS

... Educators For Students For Everyone Severe Weather 101 Thunderstorms Basics Types Detection Forecasting FAQ Tornadoes Basics Types ... moisture. What we do: NSSL researchers studied winter thunderstorms and found that there is some evidence that ...

416

Earth-Sun Geometry: Winter Solstice Animation  

NSDL National Science Digital Library

The representation depicts the position of the Earth relative to the Sun during the southern hemisphere's winter solstice and includes line of latitude and the angle of the Sun's rays at the Tropic of Capricorn.

Michael Pidwirny

417

43 CFR 423.37 - Winter activities.  

Code of Federal Regulations, 2010 CFR

...FACILITIES, LANDS, AND WATERBODIES Rules of Conduct § 423.37 Winter activities. (a) You must not tow persons on skis, sleds, or other sliding devices with a motor vehicle or snowmobile, except that you may tow sleds designed to be...

2010-10-01

418

43 CFR 423.37 - Winter activities.  

Code of Federal Regulations, 2011 CFR

...FACILITIES, LANDS, AND WATERBODIES Rules of Conduct § 423.37 Winter activities. (a) You must not tow persons on skis, sleds, or other sliding devices with a motor vehicle or snowmobile, except that you may tow sleds designed to be...

2011-10-01

419

Take Steps to Avoid Winter Falls  

MedlinePLUS

... please enable JavaScript. Take Steps to Avoid Winter Falls Check the traction of your boots, keep your ... Weather Emergencies SATURDAY, Jan. 17, 2015 (HealthDay News) -- Falls are a major cause of injuries during the ...

420

How to Find Insects Weathering the Winter.  

ERIC Educational Resources Information Center

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

Brody, Jane

1979-01-01

421

CHEMICAL ENGINEERING Fall 2013-Winter 2014  

E-print Network

ADVANCED CHEMICAL ENGINEERING Fall 2013-Winter 2014 Certificate Program CONTINUING AND PROFESSIONAL EDUCATIONCONTINUING AND PROFESSIONAL EDUCATION #12;About the Advanced Chemical Engineering Certificate Program The new Advanced Chemical Engineering Certificate Program offers professionals in chemi- cal engineering

California at Davis, University of

422

Winter warming from large volcanic eruptions  

SciTech Connect

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% 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. 21 refs., 2 figs., 1 tab.

Robock, A.; Jianping Mao (Univ. of Maryland, College Park (United States))

1992-12-24

423

Mesoscale Aspects of Winter Weather Forecasting Topics  

NSDL National Science Digital Library

The Mesoscale Aspects of Winter Weather Forecasting effort is comprised of a growing series of in-depth case exercises bundled with supporting topics. This site provides access to the supporting topics seperate from the case exercises.

COMET

2003-10-12

424

Short Communication Identification of a nucleopolyhedrovirus in winter moth populations  

E-print Network

Short Communication Identification of a nucleopolyhedrovirus in winter moth populations from: Nucleopolyhedrovirus Winter moth Operophtera brumata Polyhedron gene Covert infections a b s t r a c t Winter moth. brumata nucleopolyhedrovirus (OpbuNPV) in winter moth larvae collected from field sites in Massachusetts

Elkinton, Joseph

425

Geochemistry and flooding as determining factors of plant species composition in Dutch winter-flooded riverine grasslands.  

PubMed

Dutch water policy aims for more frequent, controlled flooding of river valley floodplains to avoid unwanted flooding elsewhere; in anticipation of increased flooding risks resulting from climate changes. Controlled flooding usually takes place in winter in parts of the valleys which had not been subject to flooding in the last decades. It may thus affect existing nature with its conservation values. The goal of this study was to clarify the geochemical and hydrological factors determining plant species composition of winter-flooded river valley grasslands. A correlative study was carried out in 43 sites in 13 Dutch river valley floodplains, with measurements of flooding regime, vegetation composition, soil nutrients and soil pH status. With the use of canonical correspondence analysis (CCA) the plant species composition was investigated in relation to the geochemical variables and the winter winter-flooding regime. We found that the distributions of target species and non-target species were clearly correlated with geochemical characteristics and flooding regime. Clustering of sites within the CCA plots has led us to distinguish between four types of winter flooding in our areas: floodplains with (a) accumulating rain water, (b) low groundwater levels flooded with river water, (c) discharging groundwater and (d) high groundwater levels flooded with river water. Our major conclusions are (1) the winter groundwater level of winter-flooded grasslands was important for evaluating the effects of winter flooding on the geochemistry and plant species composition, and (2) winter winter-flooding effects were largely determined by the nature of the flooding. A high frequency of flooding particularly favoured a small set of common plant species. In areas with groundwater seepage, winter flooding may provide geochemical conditions suitable for diverse vegetation types with rare species. Rainwater flooded sites appeared less suitable for most target species. PMID:18514261

Beumer, Victor; van Wirdum, Geert; Beltman, Boudewijn; Griffioen, Jasper; Grootjans, Ab P; Verhoeven, Jos T A

2008-08-25

426

Winter survival of Eurasian woodcock Scolopax rusticola in central Italy  

USGS Publications Warehouse

The Eurasian woodcock Scolopax rusticola is a popular game bird in much of Europe. However, little is known about its population dynamics. We estimated winter survival of woodcock in a protected area with no hunting in central Italy. We radio-tagged 68 woodcocks with battery-powered radio-transmitters during 2001-2005. Woodcocks were captured in fields at night from November through February and fitted with radios. Birds were classified on capture as juveniles or adults using plumage characteristics. Woodcocks were relocated daily through March of each year or until they died, disappeared from the study area, or until their radio failed. We constructed a set of eight competing models of daily survival for the period 1 December - 28 February. Estimates of survival were obtained using the program SURVIV and Akaike's Information Criteria. The best model suggested daily survival was a constant 0.9985 (95% CI = 0.9972-0.9998), corresponding to a survival rate of 0.88 (SE = 0.05) for the 90-day winter study period. Our estimate of juvenile survival is higher than previously reported, and may reflect the protected status of the study area. Our estimates of winter survival may be helpful in managing harvested woodcock populations as well as in conserving populations in an increasingly urbanised environment. ?? Wildlife Biology (2008).

Aradis, A.; Miller, M.W.; Landucci, G.; Ruda, P.; Taddei, S.; Spina, F.

2008-01-01

427

Winter energetics of female Indiana bats Myotis sodalis.  

PubMed

Understanding physiological limits and environmental optima is critical to developing protection strategies for endangered and threatened species. One theory to explain the decline in endangered Indiana bat Myotis sodalis populations involves increasing cave temperatures in winter hibernacula. Altered cave temperatures can raise metabolism and cause more arousals in torpid bats, both of which use more fat reserves. In addition, fluctuations in cave temperatures may cause additional arousals. Our objectives were to quantify the effect of temperature and fluctuations thereof on torpid metabolism and arousal frequency in this species. Female Indiana bats (n=36) were collected from caves just before hibernation, maintained in an environmental chamber that simulated hibernacula conditions, and had skin temperature recorded every 30 min throughout the winter. One environmental chamber containing bats (n=12) was sequentially set at 8°, 6°, and 4°C over the winter. The second chamber containing bats (n=12) experienced the same mean temperatures, but temperature fluctuated ±2°C on a regular basis. Torpor bouts were longest at 4°C and were not affected by temperature fluctuations. However, the temperature fluctuations appeared to cause longer arousals. Other bats (n=12) were individually placed in metabolic chambers to calculate oxygen consumption during torpor and during arousals. Torpid metabolism was affected by temperature; at 9°C, it was higher than at 7° or 5°C. Metabolism during arousals was not different among temperature treatments, but rates were almost 200 times higher than torpid metabolic rates. We calculated a winter energy budget and, from the energetic perspective, determined an optimum hibernation temperature (3°-6°C) for female Indiana bats. These findings suggest that hibernacula that provide these conditions deserve extra protection, although other factors in addition to energetics may play a role in temperature preferences. PMID:24457921

Day, Katie M; Tomasi, Thomas E

2014-01-01

428

Winter Morning in Northern Tharsis  

NASA Technical Reports Server (NTRS)

Mars Global Surveyor's camera, MOC, provided this hemispheric view of the northern Tharsis region on June 1, 1998. This picture shows the giant volcano, Olympus Mons, and one of the Tharsis Montes volcanoes, Ascraeus Mons. Another volcano, Alba Patera, is lurking under the haze and clouds at the top of the image. Olympus Mons is about 550 kilometers (340 miles) wide.

MGS is now in a 'morning' orbit (when it arrived at Mars in September 1997, it was inserted into a 'late afternoon' orbit). The orbit will continue to change, about one hour a month, until aerobraking into a circular orbit is complete about seven months from now. When this picture was taken, the local time on the ground beneath the spacecraft was about 9:30 a.m. The terminator-- the line that divides night and day-- was located west of Olympus Mons (left part of the image). It is winter in the northern hemisphere of Mars, and the high latitudes (i.e., north of Olympus Mons in this picture) exhibit clouds and haze. These clouds most likely contain water ice.

MOC images 33901 (the red wide angle image) and 33902 (the blue wide angle image) were obtained on Mars Global Surveyor's 339th orbit about the planet. The pictures were taken around 7:37 p.m. PDT on June 1, 1998.

Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

1998-01-01

429

Winter climate change and coastal wetland foundation species: salt marshes vs. mangrove forests in the southeastern United States  

USGS Publications Warehouse

We live in an era of unprecedented ecological change in which ecologists and natural resource managers are increasingly challenged to anticipate and prepare for the ecological effects of future global change. In this study, we investigated the potential effect of winter climate change upon salt marsh and mangrove forest foundation species in the southeastern United States. Our research addresses the following three questions: (1) What is the relationship between winter climate and the presence and abundance of mangrove forests relative to salt marshes; (2) How vulnerable are salt marshes to winter climate change-induced mangrove forest range expansion; and (3) What is the potential future distribution and relative abundance of mangrove forests under alternative winter climate change scenarios? We developed simple winter climate-based models to predict mangrove forest distribution and relative abundance using observed winter temperature data (1970–2000) and mangrove forest and salt marsh habitat data. Our results identify winter climate thresholds for salt marsh–mangrove forest interactions and highlight coastal areas in the southeastern United States (e.g., Texas, Louisiana, and parts of Florida) where relatively small changes in the intensity and frequency of extreme winter events could cause relatively dramatic landscape-scale ecosystem structural and functional change in the form of poleward mangrove forest migration and salt marsh displacement. The ecological implications of these marsh-to-mangrove forest conversions are poorly understood, but would likely include changes for associated fish and wildlife populations and for the supply of some ecosystem goods and services.

Osland, Michael J.; Day, Richard H.; Doyle, Thomas W.; Enwright, Nicholas

2013-01-01

430

Planktonic biomass variability during a late winter bloom in the subtropical waters off the Canary Islands  

NASA Astrophysics Data System (ADS)

Planktonic biomass from heterotrophic prokaryotes to mesozooplankton was assessed in the Canary Island waters in order to study the characteristic late winter bloom of subtropical waters. Weekly sampling was performed between January and August 2005 at 6 stations around the island of Gran Canaria. The bloom observed in this study showed the common increase in chlorophyll in February-March. However, the study of the biomass of different components of the planktonic community unveils a succession of peaks of monthly periodicity. The bloom started with an increase in large primary producers and was followed by several alternating peaks of heterotrophic nanoflagellates, microplankton and mesozooplankton. During the period studied, mesozooplankton, autotrophic picoplankton and heterotrophic prokaryotes showed similar trends, whereas nano- and microplankton depicted an inverse pattern. Our results show that the late winter bloom in subtropical waters is much more complex than that inferred from the simple increase in chlorophyll associated with the drop of temperature during winter.

Schmoker, Claire; Arístegui, Javier; Hernández-León, Santiago

2012-07-01

431

Physics 5B Homework Set #4 Winter 2009 DUE: WEDNESDAY FEBRUARY 4, 2009  

E-print Network

Physics 5B Homework Set #4 Winter 2009 DUE: WEDNESDAY FEBRUARY 4, 2009 Assigned reading: Giancoli-example). (a) The speed of sound in air increases as the temperature is increased from T = 0 C to T = 20 C. (b) Two linear waves have the same amplitude and speed, and otherwise are identical, except one has half

California at Santa Cruz, University of

432

Interdecadal and Interannual Variability of Winter Precipitation in Southeast China  

NASA Astrophysics Data System (ADS)

Interdecadal variability of observed winter (DJF) precipitation in Southeast China (1961 to 2010) is characterized by the first EOF of the three-monthly Standardized Precipitation Index (SPI) subjected to a 9-year running mean, while the differences from the original describe the interannual fluctuations. For interdecadal time scales the dominating spatial modes represent monopole features over Southeast China involving the Arctic Oscillation (AO) and the sea surface temperature (SST) anomalies over western Pacific. Dynamic composite analysis (based on NCEP/NCAR and ERA-40 reanalyzes) reveals the following results: (i) Interdecadal SPI-variations show a trend from a dryer state in the 1970s via an increase during the 1980s towards stabilization of wetter conditions commencing with the 1990s. (ii) In mid-to-high latitudes the weakened southward flow of polar airmasses induces low-level warming over Eurasia due to stronger Arctic Oscillation (AO) by warmer zonal temperature advection. This indicates that the precipitation increase in Southeast is attributed circulation anomalies over mid-to-high latitudes which are related to AO. (iii) The abnormal moisture flux along the southwestern boundary of the abnormal anticyclone over south Japan (and its anomalous south-easterlies) is modulated by the sea surface temperature (SST) anomalies over Western Pacific; a positive (negative) SST anomaly will strengthen (weaken) the warm and moist air flow, leading to abundant (less) precipitation in Southeast China. This demonstrates the collaborative effect of AO and SST anomalies in determining the nonlinear trend observed in winter precipitation over Southeast China. For interannual time scales the dominating spatial pattern also represents monopole patterns. Composite analysis (with resampling test) of the associated circulation anomalies reveals the following results: (i) The wet (dry) winter is a result of the strengthened (weakened) northward warm moist air over east coast of China, which is caused by the weakened (strengthened) East Asian Winter Monsoon (EAWM) due to weakening (strengthening) of Siberia High (SH) and eastward (westward) extending of East Asian Trough (EAT). (ii) The effects of El Niño and sea surface temperature (SST) anomalies over South China Sea (SCS) on rainfall in Southeast China are independent. El Niño years, the anomalous anticyclone (cyclone) over Philippines leads to positive (negative) anomalies of rainfall over South China, while in years with the anomalous positive (negative) SST over SCS (non-ENSO), more (less) water vapor is conveyed to Southeast China, thereby enhancing (reducing) precipitation over south of the Yangtze River. (iii) Contributions from all impact factors (EAWM, SH, EAT, El Niño events and SST SCS anomalies) do not counteract with one aother to generate the Southeast China winter precipitation variability.

Zhang, L.; Fraedrich, K.; Zhu, X.; Sielmann, F.

2013-12-01

433

Winter Ecology of the Western Burrowing Owl (Athene cunicularia hypugaea) in Southern Texas 1999-2004  

USGS Publications Warehouse

This study examines the winter ecology of the western burrowing owl (Athene cunicularia hypugaea) in five Texas counties surrounding Corpus Christi, in southern Texas. There is a substantial gap in information on the owl's life cycle during migration and non-breeding winter months; almost all previous research on western burrowing owls has been conducted during the breeding season. The western burrowing owl currently is federally threatened in Mexico, federally endangered in Canada, and in the United States is considered a National Bird of Conservation Concern by the U.S. Fish and Wildlife Service. Topics investigated included status, effectiveness of public outreach, roost sites and use of culverts and artificial burrows, roost site fidelity, diet, contaminant burdens, body mass, and ectoparasites. Early ornithological reports and a museum egg set revealed that burrowing owls once bred in southern Texas and were common in winter; however, since the 1950's they have been reported in relatively low numbers and only during winter. In this study, public outreach increased western burrowing owl detections by 68 percent. Owls selected winter roost sites with small-diameter openings, including culverts less than or equal to 16 centimeters and artificial burrows of 15 centimeters, probably because the small diameters deterred mammalian predators. Owls showed strong roost site fidelity; 15 banded birds stayed at the same roost sites within a winter, and 8 returned to the same site the following winter. The winter diet was over 90 percent insects, with crickets the primary prey. Analyses of invertebrate prey and regurgitated pellets showed that residues of all but 3 of 28 carbamate and organophosphate pesticides were detected at least once, but all were below known lethal concentrations. Mean body mass of western burrowing owls was 168 grams and was highest in midwinter. Feather lice were detected in low numbers on a few owls, but no fleas or other ectoparasites were found.

Woodin, Marc C.; Skoruppa, Mary K.; Hickman, Graham C.

2007-01-01

434

Simulating the influences of various fire regimes on caribou winter habitat  

USGS Publications Warehouse

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. ?? 2006 by the Ecological Society of America.

Rupp, T.S.; Olson, M.; Adams, L.G.; Dale, B.W.; Joly, Kyle; Henkelman, J.; Collins, W.B.; Starfield, A.M.

2006-01-01

435

Sustainability of winter tourism in a changing climate over Kashmir Himalaya.  

PubMed

Mountain areas are sensitive to climate change. Implications of climate change can be seen in less snow, receding glaciers, increasing temperatures, and decreasing precipitation. Climate change is also a severe threat to snow-related winter sports such as skiing, snowboarding, and cross-country skiing. The change in climate will put further pressure on the sensitive environment of high mountains. Therefore, in this study, an attempt has been made to know the impact of climate change on the snow precipitation, water resources, and winter tourism in the two famous tourist resorts of the Kashmir Valley. Our findings show that winters are getting prolonged with little snow falls on account of climate change. The average minimum and maximum temperatures are showing statistically significant increasing trends for winter months. The precipitation is showing decreasing trends in both the regions. A considerable area in these regions remains under the snow and glacier cover throughout the year especially during the winter and spring seasons. However, time series analysis of LandSat MODIS images using Normalized Difference Snow Index shows a decreasing trend in snow cover in both the regions from past few years. Similarly, the stream discharge, comprising predominantly of snow- and glacier-melt, is showing a statistically significant declining trend despite the melting of these glaciers. The predicted futuristic trends of temperature from Predicting Regional Climates for Impact Studies regional climate model are showing an increase which may enhance snow-melting in the near future posing a serious threat to the sustainability of winter tourism in the region. Hence, it becomes essential to monitor the changes in temperature and snow cover depletion in these basins in order to evaluate their effect on the winter tourism and water resources in the region. PMID:24318957

Dar, Reyaz Ahmad; Rashid, Irfan; Romshoo, Shakil Ahmad; Marazi, Asif

2014-04-01

436

Dedication to Professor Hannspeter Winter (1941 2006): Dedication to Professor Hannspeter Winter (1941 2006)  

Microsoft Academic Search

Professor H Winter. It was with great sadness that we learnt of the death of colleague and friend Professor Hannspeter Winter in Vienna on the 8 November 2006. In memory of him and the contribution he made both to our conference and to the field of the physics of highly charged ions we dedicate these proceedings. Hannspeter was one of

Bob McCullough

2007-01-01

437

Winter-to-Winter Recurrence of Sea Surface Temperature, Salinity and Mixed Layer Depth Anomalies  

Microsoft Academic Search

The mean seasonal cycle of mixed layer depth (MLD) in the extratropical oceans has the potential to influence temperature, salinity and mixed layer depth anomalies from one winter to the next. Temperature and salinity anoma- lies that form at the surface and spread throughout the deep winter mixed layer are sequestered beneath the mixed layer when it shoals in spring

Michael A. Alexander; Mike S. Timlin; James D. Scott

2000-01-01

438

Winter-to-winter recurrence of sea surface temperature, salinity and mixed layer depth anomalies  

Microsoft Academic Search

The mean seasonal cycle of mixed layer depth (MLD) in the extratropical oceans has the potential to influence temperature, salinity and mixed layer depth anomalies from one winter to the next. Temperature and salinity anomalies that form at the surface and spread throughout the deep winter mixed layer are sequestered beneath the mixed layer when it shoals in spring, and

Michael A Alexander; Michael S Timlin; James D Scott

2001-01-01

439

Do Continental Shelf Strata Contain Evidence of Rapid Late 20th Century Glacial Melting and Increased Runoff in Alaska?  

NASA Astrophysics Data System (ADS)

Over the past two decades coincident with Arctic climate warming, Alaskan glaciers have accelerated their melt rate. This potentially large release of Alaskan meltwater might be reflected in an increased fluvial discharge of both freshwater and sediment to the ocean. To test this hypothesis, historical (1950-2002) fluvial discharge records from rivers in south-central Alaska were compared to sedimentary proxy records of discharge in the Gulf of Alaska to ascertain if (1) increased glacial wastage has increased fluvial discharge and (2) if any increase in fluvial discharge correlates with a change in the type or magnitude of sediment delivered to the coastal ocean. We propose a set of textural and rock magnetic proxies that allow us to differentiate the relative contributions of fluvial discharge from marine transport processes to the resultant stratal record preserved in shelf strata, which provide a more regional and longer temporal record of sediment discharge. Cores were collected at a series of coast-proximal to coast-distal locations, focusing on the Copper River drainage basin, the largest in the region. Chronologies for the past 400 years were established using 210Pb and 137Cs, coupled with a sedimentary paleomagnetic record that is correlated to the Sitka geomagnetic observatory record for the last century and extended using the Jackson et al. 400-year global field model. All cores show an increased silt-sized sediment flux and magnetic susceptibility over the past 50 years, peaking in the early 1990s. There is no change in sediment mineralogy or U-Th-K ratios over this period, suggesting no change in sediment sources. Proxies sensitive to variability in bottom boundary layer shear stress (e.g., mean sortable silt, disaggregated inorganic grain size (DIGS) distributions) also show no change over this 50-year period. Magnetic grain size (kARM/k) is in the micron-size range, suggesting the primary incorporation of magnetite into the floc fraction. DIGS-established floc fractions and magnetic grain size are proposed as proxies for changes in the intensity of fluvial sediment discharge and they track overall down-core changes in grain size and magnetic susceptibility. Sedimentary proxy discharge trends match better with regional decadal-scale precipitation trends than with measured rates of glacial thinning, which have accelerated since 1995. Specifically, for the period 1950-1990, the summer discharge (90% of annual total) has no net trend, but the number of days of sustained high flow increased from ~ zero to close to 30 days per year following 1975. This coincides with a transition from when snowfall made up the bulk of winter- spring precipitation at sea-level to years of increased rainfall. Summertime discharges for seven rivers have remained constant or slightly decreased during the 1990s. The lack of increasing discharge over the past decade suggests that melting of valley glaciers is not appreciably contributing to net increases in freshwater discharge. Finally, a significant observation is that the increased coarser fluvial sediment flux post-1950 is relatively minor when compared to proxy records of fluvial discharge and marine dispersal and transport associated with Little Ice Age glacial activity, suggesting that recent trends in glacial melting a minor in comparison to the past 400 years.

Jaeger, J. M.; Vienne, W.; Channell, J. E.; Stoner, J.; Finney, B.

2006-12-01

440

Effects of elevated O? exposure on nutrient elements and quality of winter wheat and rice grain in Yangtze River Delta, China.  

PubMed

With the open-top chambers (OTCs) in situ in Yangtze River Delta, China in 2007 and 2008, the effects of elevated O? exposure on nutrient elements and quality of winter wheat and rice grain were investigated. Grain yield per plant of winter wheat and rice declined in both years. The N and S concentrations increased under elevated O? exposure in both years and C-N ratios decreased significantly. The concentrations of K, Ca, Mg, P, Mn, Cu and Zn in winter wheat and the concentrations of Mg, K, Mn and Cu in rice increased. The concentrations of protein, amino acid and lysine in winter wheat and rice increased and the concentration of amylose decreased. The increase in the nutrient concentration was less than the reduction of grain yield in both winter wheat and rice, and, hence, the absolute amount of the nutrients was reduced by elevated O?. PMID:23639743

Zheng, Feixiang; Wang, Xiaoke; Zhang, Weiwei; Hou, Peiqiang; Lu, Fei; Du, Keming; Sun, Zhongfu

2013-08-01