Effect of Initial Data and Physical Processes on the Heavy Rainfall Prediction in July 1998
初值及物理过程对"98·7"暴雨预报结果的影响

The low-level vortex and shear line and the accompanying severe heavy precipitation in July 1998 are successfully simulated by using non-hydrostatic mesoscale model system (ARPS). The effect factors of heavy rainfall and the possible way to improve forecast are also studied. It is found that the incompletion of the the model initial data is one of the most important reasons for unsuccessful prediction of heavy rain. The simulated 24-hour cumulated rainfall and weather systems can be reproduced by the model as the initial field was treated reasonably by using all kinds possible observational data, including the significant level data. The function of the latent heat release, PBL process and terrain of the Yunnan-Guizhou Plateau is discussed according to the model results. In addition, the evolution of the low-level vortex and shear line is analyzed, the possible maintain mechanisms for such system are also discussed.