基于雷达回波的贵阳地区对流性降水特征分析

为了深入理解贵阳地区对流性降水的时空分布特征,本文利用贵州省贵阳站2014—2016年5—8月CINRAD/CD回波资料,首先挑选出符合对流性降水回波特征的551个样本,然后从对流性降水的回波形态、发生频次、位置、日变化、生命史以及大尺度环境场六个方面进行统计与分析。结果表明:对流性降水回波形态可分为单体型、线状型和区域型,其中线状型接近50%,是贵阳地区最常见的对流组织形式;与线状型和区域型相比,单体型对流生命史最短且局地性特征明显;超过七成对流性降水发生在西南涡或西南气流存在的天气背景下;对流多发生在贵阳市西南和东南面,而北面最少;对流初始时刻存在午后和午夜两个峰值区。最后,还以三类对流性降水过程为例,对比分析其生消过程、降水范围和强度等特点。

Statistics Characteristics of Radar Echoes of Convective Precipitation in Guiyang

Using the radar data of CINRAD/CD in Guiyang, Guizhou Province, in the period from May to August in 2014-2016, the spatial and temporal distribution characteristics of convective precipitation in Guiyang area were analyzed. First, 551 cases of convective precipitation echoes were selected, and then the echoes were statistically analyzed from six aspects of morphological characteristics, occurrence frequency, location, diurnal variation, duration and large-scale background conditions. The results showed that the convective precipitation echoes can be classified into cell type, linear and regional type, of which the linear type is about 50%, being the most common form of convection organization in Guiyang area. Compared to the linear and regional types, the convective duration of cell type is the shortest and has obviously local characteristics. More than 70% of convective precipitation events occur under the southwest vortex or southwest airflow weather condition. Convective precipitation often occurs in the southwest and southeast of Guiyang and rarely in the north. Convective initiation time has two peaks in the afternoon and around midnight, respectively. Finally, three representative convective precipitation events were carefully examined in terms of lifetime, coverage and intensity of precipitation.