Mechanisms of Short-Duration Heavy Rainfall in the Western Pacific Subtropical High Area: An Analysis of Two Rainstorms of 2018 in Hunan Province, China

IF 1.6 4区地球科学 Q4 METEOROLOGY & ATMOSPHERIC SCIENCES

Atmosphere-Ocean Pub Date : 2022-01-01 DOI:10.1080/07055900.2022.2060177

Mingcai Lan, Fei Huo, Li Zhou, Shuai Jiang, Ronghui Cai, Jingjing Chen

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引用次数: 1

Abstract

ABSTRACT This study examines two short-duration heavy rainfall cases of 2018 in Hunan province, China, using observations and the NCEP FNL analyses. Short-duration heavy rainfall occurring in the western Pacific subtropical high (WPSH) area is one of the major natural hazards during spring and summer over the middle reaches of the Yangtze River basin. Rainstorms in the two cases selected showed high echo-top height but low storm centroid elevation, resembling the “low-echo centroid” structure. Weak vertical shear was observed in the mid-lower troposphere, thereby leading to a short life cycle of storms. Before the heavy rainfall events, in addition to substantial changes in convective available potential energy (CAPE) and convective inhibition (CIN), both cases were characterized by a lack of troughs and jet streams in the middle and upper troposphere over the middle reaches of the Yangtze River basin. A proper configuration of the WPSH extending to the middle reaches of the Yangtze River basin along with low-level synoptic systems (e.g. a surface convergence line or the cold air invading) favoured moisture supply and lifting mechanisms for convection and the rainstorms. During the hot afternoon hours, the thermals forming at the surface further enhanced convection and the rainstorms.

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西太平洋副热带高压区短时强降水机制——对湖南省2018年两次暴雨的分析

摘要本研究利用观测和NCEP FNL分析，对2018年湖南省两次短时强降雨进行了研究。西太平洋副热带高压区的短时强降雨是长江中游地区春季和夏季的主要自然灾害之一。在所选的两种情况下，暴雨的回波顶部高度较高，但风暴质心高程较低，类似于“低回波质心”结构。在对流层中下部观测到微弱的垂直切变，从而导致风暴的生命周期较短。在强降雨事件发生前，除了对流有效势能（CAPE）和对流抑制（CIN）的显著变化外，这两种情况的特征都是长江流域中游对流层中上层缺乏波谷和急流。向长江流域中游延伸的WPSH的适当配置以及低层天气系统（如地表辐合线或冷空气入侵）有利于对流和暴雨的水分供应和抬升机制。在炎热的下午，地表形成的热气进一步增强了对流和暴雨。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Atmosphere-Ocean 地学-海洋学

CiteScore

2.50

自引率

16.70%

发文量

审稿时长

>12 weeks

期刊介绍： Atmosphere-Ocean is the principal scientific journal of the Canadian Meteorological and Oceanographic Society (CMOS). It contains results of original research, survey articles, notes and comments on published papers in all fields of the atmospheric, oceanographic and hydrological sciences. Arctic, coastal and mid- to high-latitude regions are areas of particular interest. Applied or fundamental research contributions in English or French on the following topics are welcomed: climate and climatology; observation technology, remote sensing; forecasting, modelling, numerical methods; physics, dynamics, chemistry, biogeochemistry; boundary layers, pollution, aerosols; circulation, cloud physics, hydrology, air-sea interactions; waves, ice, energy exchange and related environmental topics.