THE MODEL IMPROVEMENT AND IT''S APPLICATION FOR DIAGNOSING SURFACE WINDS IN HUBEI COMPLEX TERRAIN AREA
复杂地形地表风场诊断模式的改进及在湖北省的应用

In consideration of the characteristics of Mei-Yu circulation and the orographic feature in Hubei province, a one-level mesoscale model developed by Mass and D.P. Dempsey was improved. After some numerical experiments and contrast with several weather cases, it is shown that the improved model has the capacity of diagnosing surface wind in the complex terrain of Hubei. For example, in case of low-level shear combined with frontal system during the Mei-Yu season, the location and intensity of surface convergence line simulated by improved model is more close to the observation result, and close to the precipitation zone. In the case of gentle breeze, the surface convergence zone is in line with the major ridge of the western mountainous of Hubei in clear days, but it is in line with the major river in the central valley of the province in clear nights. These results are all the same to the conclusions from observational study. It is shown that the time-space variation of precipitation is correlated with the orographic distribution. Therefore, the model diagnostic result is helpful for local forecasting of both surface winds and precipitation.