南京地区一次冬季雷暴过程的雷达回波特征分析

为研究雷暴发展过程中的雷达回波特征,利用S波段双偏振多普勒天气雷达对南京地区的雷暴进行了观测研究,利用雷达回波资料、地面大气电场数据、闪电定位数据及探空资料对比分析了2014年一次冬季雷暴过程与夏季雷暴的雷暴回波特征差异。分析结果表明:冬季雷暴的对流发展高度明显低于夏季雷暴,持续时间短,水平尺度小,有较大比例的正闪;影响冬季雷暴与夏季雷暴的成雷对流高度差异的主要因素是环境温度差异,冬季雷暴在较低的高度上,具有较低的环境温度,更有利于雷暴起电;对流单体中,霰粒子的存在是雷暴的一项重要特征。

Analysis of radar echo characteristics of a winter thunderstorm in Nanjing area

In order to study the radar echo characteristics in the life-cycle of thunderstorm, an S-band dual-polarization doppler weather radar was used for observation of the thunderstorms in Nanjing area. In this paper, the radar echo characteristics of a thunderstorm occurred in winter of 2014 is comparatively analyzed with that of a thunderstorm occurred in summer by using radar echo data, ground atmospheric electric field data, lightning location data and sounding data. Analysis results show that the convective height of thunderstorm in winter was significantly lower than that in summer. The winter thunderstorm has short duration and small horizontal scale, with a large proportion of positive flash; the main factor that causes the difference between the necessary convective heights of the winter and summer thunderstorm is the difference of environmental temperature. In winter the thunderstorm is at a lower altitude, and have lower ambient temperatures, which is more conducive to thunderstorm electrification; the existence of graupel in convective cell is an important feature of thunderstorms.