A Comprehensive Analysis of the Heavy Rainfall Event in Chengdu from 20:00 on August 15 to 20:00 on August 16, 2020

2020年8月15日20时至16日20时成都市出现了一次区域性大暴雨天气过程，除西南部蒲江、简阳和金堂东部未出现暴雨外，全市其余地方均出现了区域暴雨以上量级降水。本文聚焦此次天气过程，探究暴雨形成的物理机制，涵盖低能高湿环境、西南急流与东南气流作用机制、地形影响等方面。从环流形势场上看，此次天气过程是低能高湿条件配置东南气流形势的典型暴雨模型，EC细网格资料对准确预报此次区域大暴雨天气过程提供了较高的参考意义，但对东部龙泉山脉附件的大暴雨和特大暴雨存在漏报，这可能与龙泉山脉特殊地形和副高东退后稳定维持有很大的关系。From 20 o’clock on August 15, 2020 to 20 o’clock on August 16, 2020, a regional heavy rain weather process occurred in Chengdu. Except for Pujiang, Jianyang and the eastern part of Jintang in the southwest, there was no heavy rain in the rest of the city. This paper focuses on the weather process and explores the physical mechanism of rainstorm formation, including the low energy and high humidity environment, the interaction mechanism of southwest jet stream and southeast air flow, and the influence of topography. From the perspective of circulation situation field, the weather process is a typical rainstorm model with low energy and high humidity conditions in the southeast air flow situation. The EC fine grid data provides a high reference significance for the accurate forecast of the regional heavy rainstorm weather process, but there is a missing report of the heavy rainstorm and extremely heavy rainstorm near the eastern Longquan Mountains. This may be related to the special topography of the Longquan Mountains and the stable maintenance of the subtropical high East retreat.