肇庆市强对流天气的时空分布特征

Characteristics of Spatiotemporal Distribution of Severe Convective Weather in Zhaoqing City

采用2010—2015年肇庆市146个自动站3—10月的时雨量和最大风速资料,统计分析肇庆市短时强降水和雷暴大风的时空分布特征。结果表明:(1)肇庆短时强降水和雷暴大风发生的高峰期是5—8月,峰值位于5月。(2)肇庆短时强降水和雷暴大风日变化都有日强、夜弱的特征,高发期在白天的午后。短时强降水的峰值出现在17:00前后,雷暴大风的峰值则在15:00。3—6月的短时强降水在凌晨07:00前后有一个小高峰,雷暴大风在凌晨05:00有小高峰。(3)肇庆短时强降水空间分布受地形影响较明显,3—10月多发于山区与平原过渡的地区。3—6月短时强降水多发范围远大于7—10月。3—6月有呈南北向的弱(西部偏西)、强(中东部)两带,小中心分布与地形山脉间的山谷走向接近;7—10月的多发区在肇庆东部,小中心主要位于东部的东南迎风坡。(4)肇庆雷暴大风多发地多处于平原、盆地、西江沿岸等地形较为开阔处,在封开县江口附近有一个高频的多发中心。

Using the data of hourly rainfall amount and maximum wind speed from 146 automatic weather stations for 2010 -2015, this work studies the characteristics of spatiotemporal distribution of short-term severe rainfall and thunder storms in the city of Zhaoqing. The results are shown as follows. （ 1 ） They were relatively frequent in May-August, with the peak in May. （2） They wert both characterized by variations that are stronger during the daytime than the nighttime, occmring most frequently after midday. The shortterm severe rain peaked around 17：00 while the thunder storms reached the maximum at 15：00. For Match- June, the former had a minor peak around 07：00 while the latter at 05：00. （3） The spatial distribution of the short-term severe rainfall and thunder storms are significantly affected by the terrain, and they are mostly seen in the area that connects the mountains with the plain in Match through October. The short-term severe rainfall takes place much mote frequently in Match through June than in July through October. From March to June, there are two north-south-oriented zones of high occmrence, with a weak one in the west and an intense one in the central and eastern part of the city. A minor center of activity lies in a similar direction with that of the mountain valley. For July through October, the area of high occmTence is in the east of Zhaoqing with the minor center of activity mainly in the southeastern windward slope in the east of the city.