中文摘要：

利用GRAPES_meso中尺度模式和三维资料变分同化系统,以国家气象中心T213L31全球模式预报结果作为第一猜场,在对我国南方地区的探空、地面站、自动气象站和13部雷达观测径向风进行同化的基础上,对2008年6月中旬造成南方多个省份大暴雨的一次冷锋过程和7月底在福建登陆的8号（凤凰）台风的数值预报结果进行了热力和动力检验,并对模式预报降水和降水系统的结构进行了分析,总结了冷锋系统中对流降水产生的有利条件和维持机制、以及台风登陆后的结构演变,发现这次冷锋具有较强的斜压性和锋区对流不稳定性,热力动力结构与梅雨锋类似。台风＂凤凰＂登陆后减弱为热带低气压,虽然受地面摩擦影响和水汽供应的减少而导致螺旋云系减弱,但热力结构依然清晰,暖心结构被削弱,呈现高层偏暖和低层偏冷、抑制对流发展的热力结构。通过分析,初步验证了GRAPES_meso模式对这两个个例强对流降水系统的刻画能力,但仍然有必要进行更多更细地检验。

英文摘要：

A series of numerical prediction tests are carried out with the regional GRAPES mesoscale model in southern China.Three-dimensional data assimilation,which incorporated rawinsonde data,conventional surface observation,AWS data and remote-sensing data of 13 radars,is used to improve the first guess field of T213 global model output.Two severe convective precipitation processes are analyzed in this paper to validate the GRAPES model system.A cold front,which attacked the southern China in the second 10-day of June,and the typhoon ＂Fung Wong ＂,which made a landfall in Fujian on 29 July 2008,are analyzed to show the model performance.The structure of the mesoscale system is analyzed to learn the mechanism of heavy rainfall and the development of convection as well as the instability.Predicted precipitation and diagnosed radar reflection are found in accordance with the satellite image and radar observation very well.The cold front is shown and developed in a baroclinic environment.It is of severe convectively instable in the frontal zone and shows an eastward vertical slantwise structure with height.The horizontal circulation is still clear even if the spiral cloud is weakened after the landfall of ＂Fung Wong ＂.Diagnosis of thermal field displays warm upper layers and cold lower layes.The numerical results illustrate that GRAPES model is capable of predicting mesoscale severe convective systems even though additional validation should be done with more case study.