华北地区形成雷暴大风的中尺度对流系统结构特征和发展机理

雷暴大风是我国的重要灾害天气，但对其发生发展机理至今仍不十分清楚。本申请将在已有研究的基础上，通过观测资料诊断分析、数值模拟以及理论研究,对比研究华北山区和平原地区造成雷暴大风的中尺度对流系统的结构特征和触发发展机理。主要研究内容为：采用高时空分辨观测资料，分析华北地区暖季产生雷暴大风的中尺度对流系统的统计特征，以及其发生的有利环流背景特征和关键因子；揭示华北山地和平原地区产生雷暴大风的中尺度对流系统的触发条件、结构特征、发展机理及其异同，重点研究华北山地和平原地区簇状多单体的触发机制,以及平原地区线状对流的组织机制。将上述分析与典型个例的高分辨数值模拟、理想模拟结合，深入探讨华北山地和平原地区，对流系统的触发、结构特征以及大风形成机理，尤其是垂直风切变、后向入流以及云微物理等过程的作用。本项目的成果可增加对我国中尺度对流系统以及产生天气的认识和为强对流天气的业务预报提供支撑。

The thunderstorm high wind is an important disaster weather in China, but its triggering and developing mechanisms are not clear. Based on special and intensive observational data in North China, data diagnostic analyses, numerical simulation and theoretical research are employed to study thunderstorm high wind and related mesoscale convective systems (MCSs) during warm season in mountains and plains in North China. The major scientific goals are followings. Firstly, the observational data are used to reveal the statistical characteristics of MCSs associated with thunderstorm high wind during warm season in North China. The synoptic circulations and key environmental conditions which are favorable to the triggering and developing of MCSs in mountains and plains areas will be also diagnosed and compared. Secondly, the triggering, structure, developing mechanisms of thunderstorm-high-wind produced MCSs and their weather phenomena between mountains and plains are analyzed and compared to reveal main characteristics, their similarities and differences. Especially, it will focus on triggering mechanism of cluster cells in mountain and plain areas and organizational mechanism of convection lines in plain area. Thirdly, the high-resolution numerical simulation of typical cases and ideal (semi-ideal) experiments will be designed to do further studies on the structure and developing mechanism of thunderstorm-high-wind produced MCSs. Finally, based on the numerical simulation of typical cases and ideal (semi-ideal) simulation results, the triggering, structural features and thunderstorm high wind formation mechanism of convective systems in mountain and plain areas of North China, especially the role of vertical wind shear, backward inflow and cloud microphysics, are discussed in depth. The results of present study will not only contribute to the mesoscale meteorology, but also could improve the operational prediction of convections in China.