2007年云南7次强降水过程的分析研究

Research of relation about seven heavy rainfalls of Yunnan in 2007

应用实测气象资料,结合卫星云图与多普勒雷达图像分析,对2007年7月19日到8月2日云南少有的7次强降水过程进行综合分析,结果表明:高低空的西南急流是重要的影响系统,西南急流的维持为持续性强降水过程提供了水汽、动量和不稳定能量的快速传递,高原切变线与西南急流的有利配置,是7次持续性强降水过程必不可少的条件;持续性强降水出现在500hPa水汽通量大值区和水汽通量散度辐合区;卫星云图上切变云带和副高外围云带在云南汇合,切变云带和副高外围云带维持、加强的过程与强降水落区的时空分布对应较好。多普勒速度图上零速度线长时间维持"S"型,风随高度顺时针旋转,说明高层有持续的暖平流。高低层不同性质的气流配合,有利于强降水产生。

Integrated analysis of 7 times heavy rain in Yunnan from July 19 to August 2 based on actual observation weather datum and satellite cloud atlas and Doppler radar image. The results show that： high-low southwest jet stream is important effect system. The maintenance of southwest jet stream provides water vapor, momentum, fast transfer of unstable energy for the lasting heavy rain. The further configuration of plateau shear line and southwest jet stream is necessarily condition about 7 times heavy rain. The lasting heavy rain appeared on big value region of 500 hPa vapour flux and vapour flux divergence. The shear cloud band and subtropical high cloud band crossed and confluenced in Yunnan on the satellite cloud atlas. The maintenance and intensification of shear cloud band and periphery cloud band of subtropical high correspond quite well to heavy rain falling region and cloud band distribution. The zero velocity line maintains long-lasting ＂S＂ on Doppler velocity picture, and the wind circumvolved with height, these facts showed that there is warm advection at high-level. This different quality air current cooperation at high-low levels benefits heavy rain out-growth.