梅雨期持续性暴雨过程中尺度系统频发机理的研究

采用观测资料分析、高分辨数值模拟和动力学理论研究相结合的方法对不同类型梅雨期持续性暴雨过程中的多尺度特征、日变化、中尺度系统的频发机理进行研究。首先，采用观测资料分析梅雨期持续性暴雨个例（1980年以后）不同尺度影响系统的配置和差异，根据影响系统和可能机理进行分类，并采用雷达、卫星和降雨资料研究不同类型过程中对流和降雨活动的日变化特征。再针对不同类型的个例，利用半理想和真实个例的数值模拟结果，研究不同类型过程中对流和降雨活动日变化特征的差别和形成这种差别的不同环流背景特征以及局地环流的影响；然后，利用各种动力学理论方法(位涡反演、涡动动能收支、Exergy能量收支等)定量研究梅雨锋对日变化和梅雨锋、局地环流对中尺度对流系统、涡旋的影响及机理。在以上研究的基础上，给出我国不同类型梅雨锋持续性暴雨过程的多尺度配置特征，梅雨锋、局地环流对降雨日变化、涡旋、中尺度对流系统的影响机理。

This project continues to study persistent heavy-rainfall processes during Meiyu periods. The observational data analyses, high-resolution numerical simulation combined with theoretical research will be employed to further research on multi-scale features, diurnal variations, high-frequency occurrence of vortices and convective systems in the different types of persistent heavy rainfall process during Meiyu period. Firstly, the abnormal circulations and multi-scale systems in the different types of persistent heavy rainfall processes (after 1980) during Meiyu season will be revealed. The processes will be classified into several types according to the general circulations and embedded mesoscale systems. The diurnal variations of convections and precipitation among different persistent heavy rainfall process are revealed by using the satellite, radar data and surface precipitation. Secondly, on the base of diagnosis on general characteristics of different persistent heavy rainfall processes and some typical events, high-resolution numerical simulation will be designed to reveal the possible impacts of the background circulations and other synoptic disturbances on the convections and vortices along Meiyu front. The impacts of Meiyu front forcing on the diurnal variation, the possible impacts of Meiyu front and local circulation on the mesoscale convections and vortices. The mechanisms will be studied by using theoretical methods, such as, PV inversion, budget of eddy kinetic energy and Exergy. Finally, based on above-mentioned results, a schematic model related to multi-scale characteristics of persistent heavy rainfall during Meiyu period, the physical mechanisms of Meiyu front and local circulations on the diurnal variations, and mesoscale convective systems, vortices will be proposed.