广东清远一次暖区暴雨过程分析

Analysis of A Warm-sector Heavy Rain in Qingyuan, Guangdong

利用实况常规气象资料、FY-2E卫星资料及地面自动站资料,从天气形势、物理量、中尺度系统演变等方面综合分析了2017年7月上旬清远市的一次大暴雨天气过程。结果表明:该次暴雨过程是由与低空急流相对应的低层正涡度区触发的一次暖区暴雨天气过程,200 hPa辐散场起到了良好的抽吸作用,500 hPa槽前西南气流和850 hPa西南急流,促进了不稳定能量和低层水汽的积累,为暴雨的中小尺度系统发展提供了有利的条件。充足的水汽输送以及高低层涡度场的配合为该次暴雨的发生提供了水汽及动力条件。另外,该次暴雨过程与中尺度对流系统的活动直接相关,是由2个中尺度对流系统直接影响造成的。

Using observed conventional meteorological data, FY-2 E satellite data and observations from surface automatic weather stations, this paper carries out a comprehensive analysis of a unusually heavy rain that happened in early July 2017 from the aspects of weather patterns, physical quantities and the evolution of mesoscale systems. The result is shown as follows. It was a warm-sector heavy rain triggered by a low-level zone of positive vorticity corresponding to a low-level jet stream. A divergence field at 200 hPa worked as a good sucking channel and a southwesterly air flow in front of a 500 hPa trough and a southwesterly jet stream at 850 hPa helped accumulate instability energy and low-level water vapor, providing favorable conditions for the development of meso-and fine-scale systems of the heavy rain. Sufficient water vapor transport and the allocation of high-level and low-level vorticity fields served as water vapor and and dynamic conditions. Besides, the heavy rain was directly caused by two mesoscale convective systems.