The Tests of a P－σ Hybrid Coordinate Regional Climate Model Nested into a GCM

The regional climate model with P－σ incorporated coordinate is nested into a general circulation model (GCM) to simulated the severe flooding occurred over Yangtze River valley in China during the summer of 1998, and the simulated results from this one－way nested regional climate model are compared with those from the GCM. The tests indicate that the nested regional climate model has better performances than the GCM in precipitation simulation. This is mainly because the regional climate model can more realistically describe the effects of topographic dynamic and thermodynamic and so can more accurately simulate the pressure systems over and near Qinghai－Xizang Plateau than the GCM does. It is pointed out that the nested regional climate model with GCM is more effective than GCM to simulated and predict the regional climate changes, especially in those regions with obvious regional features of climate.