Impact of UK Met Office's shortwave scheme on CPTEC's global model

Current parameterization of radiation in the CPTEC's (Center for Weather Forecast and Climate Studies, Cachoeira Paulista, SP, Brazil) operational global model has its origins in the work of Harshwardhan et al. (1987). The formulation of short wave absorption by water vapor is from Ramaswamy and Freidenreich(1992). The UK Met Office's (Edwards and Slingo, 1996) and NASA/GSFC's (Chou and Suarez, 1999) radiation codes were implemented in CPTEC's global model, initially for short wave, and the impact of these implementations are being currently tested.

The focus here is on the UKMO's scheme implementation. Two four-member-ensemble ten-year model integrations, one with current model and other with UKMO's short wave implementation, were compared to assess the impact of the new scheme on the CPTEC global model's climate. The main points of operational and UKMO's implementations will be outlined and output of the two integrations will be presented and discussed. Brief considerations on CPTEC's plans on radiative parameterization will be made.