渤海西岸两次强对流天气特征分析

Analysis of the characteristics of two severe convection weather on the west bank of the Bohai sea

利用Micaps、探空、卫星云图、雷达资料,对2011年9月1日凌晨和2012年9月27日下午在渤海西岸出现的强对流天气,从环流形势、不稳定能量、云图特征、雷达回波等方面进行了对比分析。结果表明:两次过程均出现了暴雨、大风、冰雹天气,9月1日凌晨影响系统为高空槽和切变线,灾害性天气以大风为主;9月27日下午影响系统为低涡和锋面,灾害性天气以暴雨、冰雹为主。两次过程渤海西岸上空均有一定的不稳定能量。亮度温度TBB越低表示强对流天气出现的几率越大,对流云团TBB小于-42oC预示有降水出现,TBB小于-52oC的区域与大雨或暴雨相对应。雷达回波强度大于35 d Bz区域与雷雨相对应,回波强度大于45 d Bz区域与冰雹、强降水天气对应较好。

Based on the data of Micaps, sounding, satellite cloud picture and radar, the two severe convection weather on the before dawn of september 1, 2011 and afternoon of september 27, 2012 in the west bank of Bohai are analyzed from the circulation feature, unstable energy, cloud image feature, radar echo in order to improve the quality and timeliness of forecast of convection weather. As a result, two weather processes both took place rainstorm, strong winds and hail weather, before dawn of september 1, influence system were upper trough and shear line, the main disastrous weather was strong winds, in the afternoon of september 27, influence system were low vortex and frontal surface, the main disastrous weather were rainstorm and hail. Both of the two weather processes had a certain unstable energy, the lower Black Body Temperature （TBB） indicated the greater probability of severe convection weather occurred. Less than -42 ℃ of the TBB of convective cloud cluster indicated rain, the area, less than-52 ℃ of the TBB of convective cloud cluster, occurred heavy rain or rainstorm. The intensity of radar echo larger than 35 dBz corresponded to the thunderstorm area, and the intensity of radar echo larger than 45 dBz better corresponded to the hail and severe convection weather.