Simulation of different property precipitation using a regional air-sea coupled model

A regional air-sea coupled climate model based on the regional climate model RegCM3 and the regional oceanic model POM (Princeton Ocean Model) is developed and a series of experiments are performed to verify the ability of the coupled model to simulate the summer precipitation over China from 1963 to 2002 in this study. The simulation results show that the regional air-sea coupled model RegCM3-POM has a better performance in simulating the mean summer (from June to August) precipitation over China, and the distribution of the rainband in the coupled model is more accurate than that in the uncoupled model RegCM3. The improvement of the rainfall simulation ability is remarkable over the Yangtze River Valley and in South China. Compared with the ECMWF ERA40 re-analyses, the convective precipitation simulation ability of RegCM3-POM has been improved. The space correlation coefficients between the results of RegCM3-POM and ERA40 data are above 0.6, and the coefficients between the results of RegCM3 and ERA40 data are about 0.4. The stratiform precipitation simulation ability of RegCM3-POM is also improved. However, both the two models overestimate the percentage of convective precipitation, and underestimate the percentage of stratiform precipitation. In order to improve the simulation ability of precipitation, the cloud precipitation schemes of the models may be modified.