2009年5月冀中南一次春季大暴雨成因分析

利用NCEP 1 1再分析资料、常规天气图、全国自动加密观测资料和石家庄多普勒天气雷达等资料,对发生在河北省中南部的一次短时暴雨天气过程进行了分析。结果表明：风速和风向在河北中南部的辐合促进了水汽的辐合。块状回波与带状回波交接处出现最大暴雨中心,逆风区和弱辐合区与较强降水相吻合。邢台次云区的形成与发展和北部主云区的发展...

Analysis of formation reasons of spring rainstorm in May 2009 over the middle and south of Hebei province

Based on the NCEP reanalysis data（1°×1°）,the conventional weather maps,the meteorological data from intensive automatic stations and Doppler weather radar data in Shijiazhuang,a short time heavy rain process in the middle and south of Hebei province was analyzed.The results show that convergence of wind speed and wind direction in the middle and south of Hebei province promotes the convergence of water vapor.The maximum centre of heavy rain is near the place of connection of bulk echo and banding echo,and the position of strong precipitation coincides with the adverse wind area and weak convergence area.The formation and development of cloud area at Xingtai is related to the development of main cloud area in the north of Hebei province.With the extension of cloud area where temperature drops below-42 ℃,the strong and narrow banding echo is formed at Xingtai.The variations of surface intensive wind fields and the formation of mesoscale convergence line are indicative for occurrence of a short time heavy rain.Banding echo develops rapidly near convergence line on the ground,and it weakens with the disappearance of the convergence line on the ground in the middle and south of Hebei province.