气象2018，Vol.44Issue(4)：469-484,16.DOI:10.7519/j.issn.1000-0526.2018.04.001
2017年5月7日广州极端强降水对流系统结构、触发和维持机制
Structure,Triggering and Maintenance Mechanism of Convective Systems During the Guangzhou Extreme Rainfall on 7 May 2017
摘要
Abstract
A very extreme rainfall event occurred on 7 May 2017 in Xintang Town,Zengcheng District of Guangzhou with maximum hourly precipitation exceeding 180 mm and 3 h rainfall exceeding 330 mm (shortly"the 5·7 extreme rainfall event"),causing severe economic damages.The rainfall process can be divided into two stages:Huadu rainfall stage and Zengcheng rainfall stage.The severe rainfall was mainly concentrated in two or three hours.The maximum minutely rainfall was high up to 5.0 mm.About 120 mm of the rain poured between 05:30 and 06:00 BT for the extreme hourly precipitation of 184.4 mm in Xintang Town of Zengcheng.Some negative lightning was observed during the Huadu rainfall stage and only several lightning occurred during the Zengcheng convection stage.Both radar reflectivity and satellite images show that the severe convective rainfall system was characterized by small-scale and rapid develo-ping.The radar vertical profiles show the convection featured low-echo-centroid warm-cloud precipitation. There was remarkable spatial inconsistency between radar maximum reflectivity and minimum TBB of sat-ellite image during the mature stages of the convection.The strong updraft was the cause of the spatial in-consistency between radar maximum reflectivity and minimum TBB.The topographic radiation cooling formed the surface cold center near Huadu.The terrain combined with large-scale weak cold air blocked the north-moving warm,moist flow,and the convection was finally triggered near Huadu.The continu-ously transport of warm,moist air and blocking of Huadu terrain maintained the mesoscale convective sys-tem (MCS) during 01:00-03:00 BT in Huadu.The south-moving large-scale weak cold air enhanced the cold pool,and pushed the MCS to move southward rapidly in 03:00-04:00 BT.The combination of south-moving MCS and local convection enhanced the convection over Zengcheng Region.The cold pool driven theory can explain the long-time maintenance and development of the MCS over Zengcheng.Both weak ambient flow and southward surface flow made the MCS slowly move during the two heavy rainfall stages.Thus,the extremely severe rainfall over Huadu and Zengcheng of Guangzhou took place.关键词
极端强降水/结构、触发和维持机制/低质心暖云降水/地形影响Key words
extremely severe rainfall/structure/triggering and maintenance mechanism/low-echo-centroid warm cloud precipitation/terrain effect分类
天文与地球科学引用本文复制引用
田付友,郑永光,张小玲,张涛,林隐静,张小雯,朱文剑..2017年5月7日广州极端强降水对流系统结构、触发和维持机制[J].气象,2018,44(4):469-484,16.基金项目
国家自然科学基金项目(41375051)、国家重点基础研究发展计划(973计划)(2013CB430106)和国家重点研发计划(2017YFC1502003)共同资助 （41375051）
