Simulation of the Modern Summer Climate over Greater Mekong Sub-region (GMS) by ECHAM5-RegCM3

Abstract

Selected the modern summer climate over Greater Mekong Sub-region (GMS) as the simulated object, four sets of twenty-year simulation were respectively carried out by the ECHAM5 with three spatial resolutions: T42, T63 and T85, and the RegCM3 nested in ECHAM5 in one-way mode (ECHAM5-RegCM3). The performance of each model in simulating the present summer climate in GMS was investigated. The results of ECHAM5 with three spatial resolution show that the simulation of the main distribution patterns of surface air temperature but the rainfall are basically reasonable. The results of ECHAM5-RegCM3 show that the simulation performance of nested model achieved much more improvement than that of ECHAM5 in simulating temperature and precipitation, thanks to the higher resolution and improved sub-grid physical processes in the model. The 20-year averaged rates in the same anomaly sign between simulation and observation were about 60% and 65% for rainfall and temperature respectively, and the years with spatial correlation coefficient passing 0.05 significant test were 20 for both rainfall and temperature. In general, the ECHAM5-RegCM3 can be used to study the mechanism of climate variability and future climate change over GMS.