宜丰短时强降水雷达回波特征分析

使用江西自动站数据、MICAPS天气图资料、雷达拼图CR产品和单部雷达基数据等资料,采用统计分析、形态对比、特征提取等方法,对2017—2019年宜丰4次暴雨和大暴雨过程中的短时强降水天气的演变与回波特征进行分析,结果表明:(1)宜丰暴雨或大暴雨过程都出现了≥30 mm·h^-1的短时强降水。(2)200 hPa赣北处辐散分流区中,500 hPa 588 dagpm线稳定维持在江西南部,赣北处于850 hPa西南急流的左侧及前端,形成上干下暖湿的不稳定层结;地面辐合线是短时强降水的主要触发系统。(3)在短时强降水期间,雷暴回波群中超级单体回波强度为60~65 dBZ,短带回波强度为50~55 dBZ,复合体回波强度为55~60 dBZ,絮状回波带回波强度为40~45 d BZ。(4)在单部雷达回波产品上,雷暴回波群、回波短带、复合单体回波和絮带状回波,组合反射率CR为40~65 d BZ,回波顶高ET为8~15 km,垂直液态水含量VIL为10~60 kg/m²,50 dBZ强回波顶高为5~12 km。

Analysis of Short-term Heavy Precipitation Weather and Radar Echo Characteristics in Yifeng

Using Jiangxi automatic station data,MICAPS weather map data,radar jigsaw CR products and single radar-based data,the evolution and echo characteristics of short-term heavy precipitation during four rainstorms and heavy rain process in Yifeng from 2017 to 2019 were analyzed by means of statistical analysis,morphological comparison and feature extraction.The results show that:(1)Shortterm heavy precipitation occurred in Yifeng rainstorm or heavy rainstorm process.(2)In the divergence and distributary area at 200 hPa in northern Jiangxi,the 500 hPa 588 dagpm line is stably maintained in the south of Jiangxi,and northern Jiangxi is at the left and front end of the southwest jet at 850 hPa,forming unstable stratification with upper dryness and lower warmth and humidity;Ground convergence line is the main trigger system of short-term heavy rainfall.(3)During short-term heavy precipitation,the echo intensity of supercell in thunderstorm echo group is 60-65 dBZ;The intensity of short band wave is 50-55 d BZ;The echo intensity of complex is 55-60 dBZ;The echo intensity of floc echo is 40-45 dBZ.(4)On a single radar echo product,the combined reflectivity CR of thunderstorm echo group,echo short band,composite monomer echo and floc echo is 40-65 dBZ,the echo top height ET is 8-15 km,the vertical liquid water content VIL is 10-60 kg/m²,and the 50 dBZ strong echo top height is 5-12 km.