NH42A-08
Detecting Recent Atmospheric River Induced Flood Events over the Russian River Basin
Thursday, 17 December 2015: 12:05
309 (Moscone South)
Ali Mehran1, Dennis P Lettenmaier2, F Martin Ralph3 and David Anthony Lavers3, (1)University of California Irvine, Irvine, CA, United States, (2)University of California Los Angeles, Department of Geography, Los Angeles, CA, United States, (3)Scripps Institution of Oceanography, La Jolla, CA, United States
Abstract:
Almost all major flood events in the coastal Western U.S. occur as a result of multi-day extreme precipitation during the winter and late fall, and most such events are now known to be Atmospheric Rivers (ARs). AR events are defined as having integrated water vapor (IWV) exceeding 2 cm in an area at least 2000 km long and no more than 1000 km wide. The dominant moisture source in many AR events, including those associated with most floods in the Russian River basin in Northern California, is the tropics. We report on a hydrological analysis of selected floods in the Russian River basin using the Distributed Hydrology Soil Vegetation Model (DHSVM), forced alternately by gridded station data, NWS WSR-88D radar data, and output from a regional atmospheric model. We also report results of river state forecasts using a river hydrodynamics model to reconstruct flood inundation from selected AR events. We diagnose errors in both the hydrological and river stage predictions, and discuss alternatives for future error reduction.
