2.13
Off- and on-line investigations of VIC land surface scheme using RSM
Ji Chen, Univ. of California, San Diego, CA; and J. Roads, M. Kanamitsu, and A. Nunes
The variable infiltration capacity (VIC) macro-scale hydrologic land surface model is being coupled with the Regional Spectral Model (RSM). The RSM currently uses an early version of the NCEP land surface model (Noah), and is currently initialized from the operational global analyses. Initially, these land surface models were compared off-line using both observed precipitation and RSM precipitation along with RSM surface radiation and surface fluxes. Both land surface models produced relatively dry land surface conditions when forced by RSM precipitation in the Southwest, because the RSM forecast/analysis (1-day forecast) produced less precipitation than observed. The coupled version of the NCEP land surface model was even dryer over the US Southwest and this can be traced to excessive evaporation as well as deficient precipitation. A similar study using the VIC land surface model is being developed and will be compared to the coupled Noah model simulations in order to determine whether the VIC model can ameliorate the excessive evaporation (and perhaps the deficient precipitation) in the current RSM. Other water and energy budget processes are also being analyzed. Our eventual goal is to determine if increased forecast skill results from first running a land surface model forced by observed precipitation in contrast to our current forecast methodology, which initializes the regional land surface from the operational global analysis.
Session 2, Modeling and Analysis of Large-Scale Hydrological Processes (Room 6E)
Tuesday, 13 January 2004, 1:30 PM-5:30 PM, Room 6E
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