HR: 16:15h
AN: C34A-02    [Abstracts]
TI: Sensitivity of the seasonal snowcover to warming climate trends in a snow dominated semi- arid mountain basin
AU: Nayak, A
AF: Biological and Irrigation Engineering, Utah State University, Logan, Uta 834322, United States
AU: * Marks, D
AF: Northwest Watershed Research Center, USDA-Agricultural Research Service, Boise, Ida 83712-7716, United States
AU: Chandler, D
AF: Civil Engineering, Kansas State University, Manhattan, Kan 66506, United States
AU: Winstral, A
AF: Northwest Watershed Research Center, USDA-Agricultural Research Service, Boise, Ida 83712-7716, United States
AB: Temperature of the western United States has increased by 1-2 C since 1950's. Over the last 45 years of record at the Reynolds Creek Experimental Watershed (RCEW), annual precipitation is unchanged, but these climate trends have altered the snowmelt dominated hydrologic cycle. More precipitation falls as rain, causing earlier snowmelt, earlier peak streamflow, reduced peak snow water equivalent, and reduced summer soil moisture and stream flow. Natural variation in weather and precipitation (wet-dry precipitation and warm-cold weather cycles) make it difficult to quantify the impacts of warming climate on hydrology. This study aims at understanding the differences in sensitivity of wet and dry snow seasons to the warming climate. For this purpose simulation of four snow seasons, representing range of precipitation (wet and dry) and temperature (warm and cold) conditions will be done using a spatially distributed snow energy and mass balance model (Isnobal). The four water years selected represent a range of conditions from early in the RCEW record to recent. The1984 water year (WY) was cold and very wet, the 1987 WY was cold and dry, the 2001 WY was warm and dry, and the 2006 WY was warm and wet. The sensitivity of the development and ablation of the seasonal snowcover to warming climate trends will be evaluated by altering temperature and humidity during the simulations. The 1984 adjusted simulation will use temperature and humidity conditions from 2006, 1987 will use temperature and humidity from 2001, 2001 will use temperature and humidity from 1987, and 2006 will use temperature and humidity from 1984. Comparison of the simulation results for the selected snow seasons under actual and adjusted forcing data would be helpful in understanding the impacts of climate warming on snow hydrology and the differences in sensitivity of wet and dry snow seasons to the warming climate.
DE: 0736 Snow (1827, 1863)
DE: 0740 Snowmelt
DE: 0762 Mass balance (1218, 1223)
DE: 0764 Energy balance
DE: 0798 Modeling
SC: Cryosphere [C]
MN: 2007 Fall Meeting