Tuesday, 11 February 2003
Development of a Large-Scale Hydrologic Prediction System
The Scripps ECPC (Experimental Climate Prediction Center) is developing an experimental off-line hydrologic prediction system for the southwestern United States. The system includes the atmospheric Regional Spectral Model (RSM) and the Variable Infiltration Capacity (VIC) macro-scale hydrologic land surface model. In particular, RSM daily forecasts of precipitation, temperature (max and min), wind speed, and solar radiation are used to continuously force water and energy balance modes of the VIC model at sub-daily scales. VIC daily, weekly and monthly forecasts are made from the routine ECPC RSM forecasts for the Southwest forecasts. Daily Land Data Assimilation System (LDAS) products are being used to validate the performance of this system. As will be shown, there are noticeable differences between the streamflow (and other hydrologic variables) forecasts and continuous simulations due to various biases in the forecast variables (especially precipitation). As long as these forecast biases are empirically corrected, useful predictions can be made.