2017年江西汛期设区市城区暴雨回波特征分析

使用江西WebGIS雷达拼图和自动站雨量、雷电监测、强天气监测等数据,以及MICAPS常规天气图资料,对2017年3—7月江西汛期11个设区市26次城区暴雨过程的雷达回波特征进行分析。结果表明:2017年江西汛期共出现52日暴雨过程,其中江西11个设区市所在地城区出现26次暴雨。在这26次城区暴雨个例中,有23次伴随出现短时强降水,有3次降水比较均匀。暴雨维持时间长短不一,最长的有15 h,最短只有3 h,平均是10 h。有5次出现大风天气,21次没有大风出现。雷达回波特征主要有3种:块状(强单体、超级单体)、带状(飑线、回波带)、絮状(絮带、絮团)。这3种回波形态特征,出现率最高的是絮状回波,即比较宽、嵌有中等强度的对流单体絮带状回波带,强度40～55 dBz,出现16次,概率62%;其次是窄而长、紧密排列由强单体组成的飑线回波带,强度50～60 dBz,出现8次,概率30%;块状(强单体、超级单体)回波强度最强,中心强度达到60～70 dBz,出现2次,概率8%。

Analysis on characteristics of rainstorm echo in flood season districts and cities of Jiangxi Province in 2017

Using the data of Jiangxi WebGIS radar mosaic, automatic station rainfall, lightning monitoring, severe weather monitoring and MICAPS conventional weather map data, this paper analyzes the radar echo characteristics of 26 rainstorm processes in 11 districts and cities in Jiangxi during the flood season from March to July, 2017. The results show that there are 52 rainstorm processes in the flood season of Jiangxi in 2017, among which 26 rainstorm processes occur in the urban areas of 11 districts and cities. Twenty-three out of twenty-six rainstorm processes in urban area are accompanied by short-term strong precipitation and 3 were accompanied by relatively uniform precipitation. The rainstorm duration ovaries, with the longest lasting 15 hours and the shortest lasting 3 hours, averaging 10 hours. Strong wind occurred for five times. There are mainly three kinds of radar echo characteristics:blocky (strong monomer, super monomer), banded (squall line, echo band), flocculent (flocculent band, flocculent dough). The flocculent echo occurs most frequently among the three echo characteristics, The flocculent echo is a wide echo band embedded with convective monomer with moderate intensity of 40-55 dBz, appearing 16 times, with a probability of 62%. It is followed by a squall line echo band, which is narrow, long and closely arranged and composed of strong monomers, with an intensity ranging from 50 dBz to 60 dBz, appearing eight times with a probability of 30%. Blocky (strong monomer, super monomer) echo has the strongest intensity, with the center intensity reaching 60-70 dBz, appearing twice, with a probability of 8%.