广西一次暴雨过程的数值预报产品位涡特征分析

Potential Vorticity Analysis of ECMWF Thin-grid Numerical Predication Products of a Rainstorm in Guangxi

利用广西自动观测站雨量资料、欧洲中心细网格数值预报位涡产品(简称EC-THIN PV产品)及风场产品,对广西2015年5月21-23日暴雨过程进行分析。结果表明,EC-THIN PV产品对位涡异常扰动具有预报灵敏性;EC-THIN PV产品高位涡区与3h强降水落区具有较好的空间对应关系,700h Pa等压面位涡高值区与短时强降水落区对应关系最好;EC-THIN PV产品500h Pa等压面产生位涡扰动,扰动下传形成高位涡柱的过程,与中尺度低涡形成、发展及短时强降水的产生具有较好的时间同步性。

Based on the rainfall data from automatic weather observation stations in Guangxi, potential vorticity of EC-THIN PV products and wind products, the rainstorm process appearing during 21 to 23 May in Guangxi was analyzed. The results show that EC-THIN PV products are sensitivity for predicting anomalous disturbance of PV; High PV areas of EC-THIN PV products have good spatial correlation with failing areas of 3h short-time heavy rainfall, and high PV in 700hPa pressure level have the best correlation with the short-time heavy raining area; The processes of appearing PV anomalous disturbance and downward propagating to form PV anomaly column has time-synchronization with the forming and development of the meso-scale vortex and occurring short-time heavy rainfall.