一次短历时特大暴雨系统的高分辨率卫星图像

High Resolution Satellite Image of a Very Short Range Torrential Rain

利用水平分辨率为1.25km的FY2-C地球同步卫星的可见光云图,对2005年8月14日发生在北京北部山区一次百年一遇的短历时特大暴雨进行了云图分析,发现高分辨率的可见光云图可以在一个多小时前就识别出水平尺度只有几公里的初始对流,并可利用它在地面上的阴影判别其垂直发展的强度。暴雨发生前水平尺度发展到数十公里,其云顶上的暗影表明强烈的对流已突破对流层顶。

A 100-year return period heavy rain event of 220 mm precipitation in 80 min happened at mountainous areas in north of Beijing on August 14, 2005 was studied with the help of the visible cloud images of 1.25 km resolution from FY2-C geostationary satellite. The results show that the initial convective cells with several kilometers of horizontal scale can be identified by using the high resolution satellite images ahead of 1.0-1.5 h of rainfall, and the intense of the convective cell can be estimated by the shadows projecting on the ground. The horizontal scale of the convective clouds develope to couples of ten km just prior to the rainfall, and the shadows on the fiat cloud top indicate that the convection is extremely intensified and breaks up through the tropopause.