The Superiority and The Sensitivity Experiments of Betts-Miller Cumulus Scheme in Regional Climate Simulation of Summer Monsoon Rainbelts over Eastern China

摘要

Some regional climate simulations have demonstrated their capacities of reproducing location and evolution of the rainbelts in Eastern China during the summer monsoon season. But the simulated intensity and scope of heavy rainfall area do not always exactly coincide with the observations. The defect of the precipitation simulation may mainly related to the cumulus convection parameterization scheme. In this study, by using NCAR regional climate model (REGCM2), we test three cumulus convection parameterization schemes, Betts-Miller(referred to BM hereafter) , Kuo and Grell schemes, in the regional climate simulations of the summer season of 1991 and 1994, compare their performances in the simulation of precipitation and the fundamental meteorological element fields, verify their climate simulation abilities in Eastern China monsoon area. The results indicate that BM scheme is most superior, compared to the other two schemes. Finally, the sensitivity tests of BM scheme's three adjustable parameters, stability parametera, convection adjustment time scale. and saturation pressure departure AP* at cloud base and the freezing level are conducted. The optimum values of adjustable parameters of BM scheme are presented, which improves significantly the climatic simulation of thermodynamics structure and precipitation during summer monsoon season in Eastern China.