广丰局地极端大风的雷达观测与成因分析

Radar observation and cause analysis of extreme strong winds in Guangfeng local area

利用常规天气资料、自动站资料、江西WebGIS雷达拼图、风廓线雷达等资料,对2020年5月9日发生在江西省上饶市广丰区局地极端大风天气的回波演变特征和形成机理进行分析。结果表明:(1)广丰区国家气象观测站出现的35.5 m·s^(-1)极端大风,为该站建站以来的历史极值;(2)江西高空具有明显的高层辐散,配合高空槽、低层较强辐合和上干冷下暖湿的层结条件,为风暴发展提供了良好的动力条件;(3)导致广丰区极端大风天气的是A、B单体回波合并为超级单体回波后又发展成弓状回波结构所致;(4)江西东部走廊对大风的影响十分明显;极端大风过境时,具有气压上升,降水增大,风向突变,风速巨变,温度和露点下降等特征;(5)风廓线雷达上1000 m以上低空突然风向逆转,风速突增是出现地面大风的信号。

Based on conventional weather data,automatic station data,Jiangxi WebGIS radar mosaic,wind profile radar and other data,the echo evolution characteristics and formation mechanism of local extreme gale occurred on May 9,2020 in Guangfeng district,Shangrao,Jiangxi Province were studied by using synoptic and echo analysis methods.Results show that:(1)the extreme strong wind of 35.5 m·s^(-1) at the national meteorological observatory in Guangfeng district is the historical extreme since the establishment of the station;(2)Jiangxi has obvious upper level divergence in the upper atmosphere,combined with strong convergence in the upper trough and lower levels,and the stratification conditions of dry,cold,and warm,wet above,providing good dynamic conditions for the development of storms;(3)the extremely windy weather in Guangfeng district is caused by the merging of single echo A and single echo B into supercell echo and then developing into bow echo structure;(4)the impact of strong winds on the eastern corridor of Jiangxi is very obvious;when extreme winds pass through,they have the characteristics of rising atmospheric pressure,increasing precipitation,sudden changes in wind direction,significant changes in wind speed,and a decrease in temperature and dew point;(5)the sudden reversal of wind direction and sudden increase in wind speed at low altitudes above 1000 m on the wind profile radar is a signal of strong ground winds.The research results provide analytical methods and reference basis for monitoring and warning of such local strong winds.