The enhanced version of the Biosphere-Atmosphere Transfer Scheme (BATS) which is described by White (1998) has been fully implemented into the FSU Nested Regional Spectral Model (FSUNRSM) (Cocke 1998; Cocke and LaRow 1998). We have used this model, to investigate the response to El Nino-Southern Oscillation (ENSO) forcing over the southeastern United States and South America.
Most modeling studies of ENSO teleconnections have tended to neglect the role of land surface processes in modulating the responses over continental domains. We have developed a seasonal forecasting system which takes advantage of the strengths of both BATS and the FSUNRSM. Currently the global model is run at a resolution of T63 (~1.875 degree) and the regional model is run at approximately 40 km resolution on a Mercator grid. We have concentrated thus far on comparison of modeled precipitation and other fields from the contrasting ENSO phases of winter 1987/88 and winter 1988/89. Simulations have been done using both the enhanced BATS and using the old surface energy balance scheme previously associated with the FSUNRSM. The model is run out four months starting on November 1, using observed sea surface temperatures. Use of the enhanced BATS scheme for this application is of special interest in order to be able to describe the impacts of ENSO on surface variables other than precipitation and to investigate detailed components of the surface hydrological budget. Variations in soil moisture, under different ENSO forcing, are especially of interest to the agricultural and economic communities. Preliminary results relative to the 1997/98 ENSO may also be presented. We are working towards linking this modeling system with the HOPE ocean model for eventual use in real-time predictive mode.