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Roy W. Spencer and David A. Santek

, twofrequencies am needed to remove most of the effect that variations in thermometric temperatures and soilmoisture have on the brightness temperatures. Because snow cover is also a volume scatterer of microwaveenergy at these micmwavelengths, a discrimination procedure involving four of the SMMR channels isemployed to separate the rain and snow classes, based upon their differences in average thermometrictemperature.1. Introduction The global distribution of thunderstorm activityover land has usually

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Gerd Wendler, Nobuyoshi Ishikawa, and Yuji Kodama

is in contrast to most studies at lower latitude~ The heat flux in and out of the snowcover was small, and showed a typical sinusoidai diurnal variation. The mean daily values of snow heat fluxwere negative, as the snow cover was wanned during tbe observational period. The latent heat flux was negative,on the average, as soblimation look place for most of the time. Deposition was observed only on a few nip, his.The sensible heat flux was negative around noon, but positive for most of the day

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R. Chawn Harlow

, modeling these emissivities has been a research objective for the past two decades. Simulation of emissivity of deserts, snow-covered land, sea ice, glaciers, and land areas that have significant water fraction such as wetlands or those containing large lakes and rivers are challenging ( Hilton et al. 2005 ; Prigent et al. 2000 ; Mätzler 1994 ). The emissivity of snow-covered surfaces is particularly difficult to model because of the effects of volume scattering that phases in and out with freeze

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Robert L. Hendrick, Bruce D. Filgate, and Walter M. Adams

sequences of rapid melt days are run through the model to estimate effects of watershedenvironment on snowmelt. Rapid snowmelt runoff is extremely unlikely except in environmentally homogeneous watersheds or during unusual weather sequences in which sensible heat and condensation heatenergy are added rapidly and uniformly to the entire watershed snow cover. As most of the snowmelt innorthern New England results from solar radiation over watersheds of great environmental diversity, theregion appears to

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Martin Schneebeli and Martin Laternser

. Schneebeli . 2002 . Temporal trend and spatial distribution of avalanche activity during the last 50 years in Switzerland. Nat. Hazards 27 : 201 – 230 . Laternser , M. and M. Schneebeli . 2003 . Long-term snow climate trends of the Swiss Alps (1931–99). Int. J. Climatol 23 : 733 – 750 . Martinec , J. and B. Sevruk . 1992 . Snow cover. Snow Cover Measurements and Areal Assessment of Precipitation and Soil Moisture, Operational Hydrology Rep. 85, WMO-No. 749, 115–217 . McClung

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J. Wang, M. R. Hjelmfelt, W. J. Capehart, and R. D. Farley

–restore, surface energy balance parameterization, which is based on the work of Noilhan and Planton (1989) and Pleim and Xiu (1995) . In this version of ARPS, snow is included as a land surface type, but snow depth and snow cover processes are not included. Snowfall does not change the land surface type. Snow on the surface is recognized only on initialization and is treated as an “on–off” state variable, which alters the surface soil albedo and thermal properties, evaporative flux, and surface temperature

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Stewart J. Cohen

planning for snow removal. Snow removal is often accomplished by spreading road salt over snow- and ice-covered roads, thusimproving traction and reducing the risk of vehicles skidding along slippery surfaces. This study demonstratesthe computation of "salt days," a user-oriented climatic variable that indicates the number of days whenroad salt is required. This variable is defined using certain temperature nod snowfall criteria. Results of apilot study indicate that it is possible to provide

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E. Vowinckel and Svenn Orvig

snow covered. It is possible to design a climatic classification for polar climates ~vhich specifies such climates to existwhen a certain percentage of the surface heat income is contributed by atmospheric (back) radiation fromwarm air brought in by advection.1. Introduction A model for energy budget calculations has previously been described, as well as its application to aparticular synoptic situation (Vowinckel and Orvig,1969a,b). Calculations will generally show resultssomewhat different

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B. K. Lunde

increases with snow cover in winter, but cities have less radiance than thecountry. In the early summer the country has low radiance in the near infrared, and in the late summer it haslow radiance in the visible region of the spectrum; the radiance of urban areas follows these trends in a verylimited way.1. Introduction There has been extensive work worldwide on urbanclimate (Chandler, 1970) and some work on measurement of radiance on a larger than planetary scale(Nordberg et al., 1962; Bray and

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Yves Durand, Martin Laternser, Gérald Giraud, Pierre Etchevers, Bernard Lesaffre, and Laurent Mérindol

1. Introduction Since the early 1990s, Météo-France has used an automatic system based on three numerical models to simulate meteorological parameters, snow cover stratigraphy, and avalanche risk at various altitudes, aspects, and slopes for a number of mountainous regions (massifs) in France ( Durand et al. 1999 ). This SAFRAN–Crocus–MEPRA 1 (SCM) model chain, usually applied to operational avalanche forecasting, is used here for retrospective snow and weather climate analyses. A 10-yr snow

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