一次强降水过程的干侵入分析

为了研究内蒙古地区干侵入与暴雨短时强降水相关性，认识实际系统的演变和发展及其对短时强降水暴雨的发生发展的作用进行诊断分析，基于气象观测资料、NCEP 1°×1°再分析资料和FY-2C2D卫星资料，通过卫星水汽图像和大气动力场相结合的方法揭示东北冷涡影响下2014年7月7日发生的内蒙古兴安盟地区降水过程中干侵入的特征及其对短时强降水发生发展的作用机制。结果表明：（1）对于这次过程而言东北冷涡是直接影响系统，明显有从对流层高层到对流层低层的干侵入，对流层高层具有低湿、高位涡的冷空气不断地向对流层的中下层侵入，促使低层出现了“上干冷，下暖湿”的垂直结构，有利于对流不稳定层结的形成，此时在地面锋面斜压性非常强，使暖湿空气抬升有利于形成短时强降水，出现强降水出现时间段均与低层不稳定最强及θ_se等值线呈上下密集分布的时刻。（2）在红外云图上表现为形成逗点云系，黑体亮温高值区与干冷区相对应，干冷区的伸入使得对流云团边缘亮温梯度增大，中心亮温值达到-53℃，短时强降水发生在对流云团东侧亮温梯度最大区域，短时强降水落区与梯度较大的区域移动方向一致。

Analysis of Dry Intrusion Impacts on a Short-time Heavy Rainfall Process

In order to research dry intrusion and Short-time Heavy Rainfall correlation in Inner Mongolia, understand the evolution and development of the actual system, and analyze and diagnose its impact on the short-time strong rainfall occurrence and development, the NCEP 1°×1° reanalysis data，FY-2C2D satellite images, conventional meteorological data and the method of combining satellite cloud images with atmospheric dynamic field were used to analyze the dry intrusion characteristics under the influence of cold eddy and the role of the dry intrusion during the short-time strong rainfall which occurred in Xingan league of Inner Mongolia on July 7, 2012. The results were as follows: (1) for this process, northeast cold vortex was the direct influence system, which had an obviously dry invade from the upper troposphere to the lower troposphere and the cold air of high vortex formed low humidity of upper troposphere to middle and lower troposphere, resulted in a vertical structure of lower layer with "upper dry and cold, under warm and wet" and was conducive to the formation of convective unstable stratification. In this case, the ground frontal baroclinity was very strong, so the lifting of warm and moist air promoted the formation of short-term heavy rain, and the rainy time was identical to the time of the strongest lower instability and in the area of upper and lowerθ_se dense distribution.(2) Comma cloud was formed in the infrared cloud image, the high value zone of brightness temperature of blackbody was corresponded with dry and cold zone, and brightness temperature gradient of convective cloud edge increased with the inserting of dry and cold area, and the center brightness temperature reached -53℃, short-time strong precipitation occurred in the east of the largest zone of brightness temperature gradient of convective cloud and the falling region of short-time strong precipitation was consistent to the moving direction of gradient larger area.