FY3极轨卫星资料在暴雨短时预报中的应用分析

Application of FY3 Satellite Data in Short-term Rainstorm Forecast

利用常规观测、地面加密自动站降水资料以及FY3B极轨卫星资料,对2014年5月18日广西一次暴雨过程中暴雨云团的微波湿度计特征进行分析,得出以下结论:(1)广西中东部处受高空槽前西南气流影响,中低层水汽条件较好,低层有切变辐合,为中尺度对流系统的发生、发展提供了有利背景。(2)250m分辨率可见光通道云图上对流发展旺盛的云团有明显不均匀纹理结构,其中镶嵌着多个圆形的暗影,预示着云中伴有强降雨、雷暴大风等灾害性天气。(3)微波湿度计资料反映出暴雨云团从低层到中高层都有较高的水汽含量,50mm以上的强降雨区主要位于3个亮温低值中心的过渡区域,即对流云团合并处。高低层通道亮温差能反映云团对流的强弱程度,强降雨发生在微波亮温差的正值区,通道3与通道5的亮温差对6h强降雨落区有较好的指示意义。

By using conventional observations data, precipitation data from ground-encrypting automatic stations, and FY3B polar-orbiting satellite data, the characteristics of the microwave hygrometer during a rainstorm in Guangxi in May 18, 2014 were analyzed. It was concluded that： （1） the upper troughs and adequate water vapor in the middle and lower layers and shear convergence at lower level provided an advantageous background for the occurrence and the development of mesoscale convective systems. （2） Convectively cloud had an uneven texture structure in 250m resolution visible light channel cloud image, in which many circular shadows were embedded, indicating that it was accompanied by severe weather such as heavy rain, thunderstorms, and winds. （3） The microwave hygrometer data reflected that the rainstorm cloud had enough moisture from the lower layer to the middle and upper layers, and the heavy rainfall areas were mainly located in the transitional area of three low value centers of bright temperature, where convective cloud cluster merged. The bright temperature difference between high and low-level channels could reflect the intensity of convection. Heavy rainfall occured in the positive area of the microwaves bright temperature difference, and the bright temperature difference in channel 3 minus channel 5 was important for the 6h strong rainfall forecasting.