HR: 1340h
AN: U53A-0720    [Abstracts]
TI: Runoff Simulation over the Sierra Nevada Region Using a Coupled Regional Climate Model
AU: * Jin, J
EM: JimingJin@lbl.gov
AF: Berkeley National Lab., One Cyclotron Road, MS-90-1116, Berkeley, CA 94720
AU: Miller, N L
EM: NLMiller@lbl.gov
AF: Berkeley National Lab., One Cyclotron Road, MS-90-1116, Berkeley, CA 94720
AB: The land surface scheme (NOAH) in the current version of the Penn State-National Center for Atmospheric Research (NCAR) fifth generation Mesoscale Model (MM5) insufficiently treats snowmelt runoff over the Sierra Nevada region due to an insufficient treatment of the snow processes. To improve snowmelt runoff simulation, we have coupled the newly released NCAR Community Land Model version 3 (CLM3) to MM5. CLM3 physically describes the mass and heat transfer within the snowpack using 5 snow layers that include liquid water and solid ice. Interactions among the snow, soil, and vegetation are a function of the CLM3 mass and energy equations. Additionally, a river routing scheme has been adopted in CLM3 to better describe the runoff hydrograph. Several observed datasets from different sources were used to evaluate the model output, including snow depth, temperature, and precipitation from the automated Snowpack Telemetry system, snow cover and vegetation indices from the MODIS satellite data, and streamflow data from the U.S. Geological Survey. In this presentation, we describe the results from an MM5-CLM3 integration from April 1 to June 30, 1998 with 60 km and 20 km nested domains. The results indicate that the coupled model significantly improves the simulation of the snow mass, resulting in a better description of the runoff in the Sierra Nevada region. The application of the river routing scheme further improves the runoff hydrograph simulation. Meanwhile, MM5-CLM3 produces better simulations for the surface air temperature and precipitation as it has more realistic descriptions of the surface energy balance and hydrological cycle when compared to the original version of MM5 with the NOAH land surface model. The coupling of the advanced CLM3 with MM5 significantly improves the regional hydroclimate and water resources predictability.
DE: 4805 Biogeochemical cycles (1615)
SC: Union [U]
MN: 2004 AGU Fall Meeting