“6·22”广东局地特大暴雨成因分析

Analysis of the Causation of a Local and Exceptionally Heavy Rain on June 22,2017 in Guangdong

综合利用NCEP/NCAR 1°×1°再分析资料及1°×1°地形网格数据、Micaps区域自动站逐时资料、FY-2G卫星TBB资料,对2017年6月22日凌晨广东阳春至恩平一带的局地特大暴雨进行分析,结果表明:副热带高压西伸、南支槽东移以及低层南风风速辐合,为该次特大暴雨发生提供了有利的动力条件;低空急流和地形抬升作用对强降水触发起着关键作用;局地经圈环流的正反馈机制使得南风急流和南海水汽输送加强,强降水维持;温度平流零线附近(垂直方向)、等θse线密集区、垂直上升速度中心区,均与强降水落区有很好对应关系。

Comprehensively using the NCEP/NCAR reanalysis and terrain mesh data, hourly data from Micaps regional automatic weather stations and TBB data from FY-2G weather satellite, this work studies the a local and exceptionally heavy rain that took place in Yangchun through En＇ ping, Guangdong province in the early morning of June 22, 2017. The results are shown as follows. Favorable dynamic conditions for this rain included the westward extension of a subtropical high, the eastward progression of a southerly trough and the convergence of low-level southerly wind. A low-level jet stream and topographic uplifting were essential in triggering the intense rain. A positive feedback mechanism of the local meridional circle strengthened the southerly jet stream and the transport of water vapor from the South China Sea, maintaining the intense rain. The zones of zero （vertical） temperature advection contours, concentrated isolines of se and vertical ascending velocity cores were all well corresponding to the zone of intense rain.