Comparison of RegCM3 simulated meteorological parameters in Bangladesh: Part I-preliminary result for rainfall

A Regional Climate Model of version 3 (RegCM3) is employed for the study of meteorological parameters in Bangladesh. To adopt the RegCM3 for this region comparison of model outputs with surface observational data is essential. In this connection, this paper represents the comparison of model rainfall with surface observational data of 29 stations throughout the country collected by the Bangladesh Meteorological Department (BMD). RegCM3 is run at 0.54° × 0.54° horizontal grid resolution in two parameterizations: Grell scheme with ArakawaSchubert (GAS) and Fritch-Chappell (GFC) assumptions. GAS run used Lateral Boundary Conditions (LBCs) data for 1995-2000 whereas GFC run used LBC data for 1991, 1994, 1996 and 1999. For the entire rainy season (March-November), model estimates about 101% of the surface rain for GFC option whereas model overestimates in pre-monsoon and underestimates in monsoon periods. The GFC option is found better than the GAS option in estimating rainfall by the model.