浙江一次梅雨期强降水过程的诊断分析

Diagnostic Analysis of a Heavy Rainfall Process in Zhejiang Province during Meiyu Period

利用亚洲地区地面气象台站常规气象资料、NCEP/NCAR和ECMWF再分析资料,分析2019年7月8~14日浙江地区梅雨期暴雨的特征和成因。结果表明:(1) 2019年浙江地区梅雨的主要特点为暴雨过程频繁、强降水区重叠、“冷黄梅”明显。(2) 降水区呈明显的东西带状分布,为典型的梅雨锋暴雨降水分布特征。(3) 稳定的环流形势,急流和高空辐散场的维持,东亚大槽的发展,活跃的短波槽和低空切变线系统,为浙江地区的持续降水提供了有利条件。明显的水汽辐合中心,假相当位温场锋区,降水区存在不稳定性。水汽条件、涡度等动力热力条件均有利于暴雨的发生。

Based on the conventional meteorological data of ground meteorological stations, reanalysis data of NCEP/NCAR and ECMWF, analyzes the characteristics and causes of Meiyu rainstorm in Zhejiang from July 8 to 14, 2019. The results show that: (1) In 2019, the main characteristics of the Meiyu are frequent rainstorm, overlapping of heavy rainfall areas and obvious cold Huangmei in Zhejiang province. (2) Large-scale rainstorm processes are obviously East-West zonal distribution, which is a typical distribution feature of Meiyu Front Rainstorm. (3) Circulation field shows that the stable circulation situation, the maintenance of jet stream and high-altitude divergence field, the development of East Asian Trough, the active short wave trough and low-level shear line system provide favorable conditions for the continuous precipitation in Zhejiang Province. There are obvious convergence centers of water vapor, high value area of pseudo equivalent potential temperature field, and instability in precipitation area. The dynamic and thermal conditions, such as water vapor and vorticity are favorable for the occurrence of rainstorm.