一次典型东风波极端暴雨的中尺度特征及地形影响分析  

Analysis of mechanism of topographic influence and meso-scale convective characteristics of an extremely severe rainfall affected by typical easterly wave

作　　者：胡振菊 黎璐 黄小玉 何炳文 叶日新 HU Zhenju;LI Lu;HUANG Xiaoyu;HE Binwen;YE Rixin(Key Laboratory of Hunan Province for Meteorological Disaster Prevention and Mitigation,Changsha 410118,China;Changde Meteorological Bureau of Hunan Province,Changde 415000,Hunan,China;National Meteorological Centre,Beijing 100081,China)

机构地区：[1]气象防灾减灾湖南省重点实验室,湖南长沙410118 [2]湖南省常德市气象局,湖南常德415000 [3]国家气象中心,北京100081

出　　处：《干旱气象》2022年第1期73-83,共11页Journal of Arid Meteorology

基　　金：湖南省气象局重点项目(XQKJ18A002);湖南省气象局预报员专项(XQKJ19C001、XQKJ21C002)共同资助。

摘　　要：利用湖南省常规气象观测资料、区域自动站资料、NCEP再分析资料、常德多普勒雷达资料,分析2016年8月8—15日在多个东风波倒槽接力影响下,湘北地区反复出现的极端暴雨天气的中尺度特征,并利用WRF-ARW中尺度数值模式,对8月10—11日湘北地区极端暴雨过程进行数值模拟和地形敏感性试验。结果表明:(1)1604号台风在广东深圳登陆后沿西北路径移动和1605号台风在西北太平洋向北移动后,副热带高压快速西伸控制华东及沿海地区,其底部的东风波扰动为极端暴雨提供了环流背景;(2)近地面不均匀加热为东风波槽附近强对流提供了充足的热力不稳定条件,地面中尺度辐合线为对流的触发和加强起到重要作用;(3)东风波槽带来的边界层暖湿气流在武陵山东侧激发深厚中尺度涡旋,是极端暴雨形成的主要原因;(4)地形敏感性试验进一步验证了东风波暖湿气流在武陵山脉地形抬升和阻挡作用下,在迎风坡上游地区形成气旋性辐合导致暴雨增幅。Based on conventional observation data, regional automatic station data of Hunan Province, NCEP reanalysis data and Changde Doppler radar data, the mesoscale characteristic of extreme rainstorms occurring repeatedly in the north of Hunan Province from 8 to 15 August 2016 affected by several easterly waves was analyzed comprehensively. The effect of the Wuling mountains topography on rainfall increase was further verified by WRF-ARW mesoscale numerical experiments. The results are as follows:(1) After the typhoon 1604 landing at Shenzhen of Guangdong Province and moving northwestward and the typhoon 1605 moving northward, the western Pacific subtropical high rapidly extended westward and controled east China and coastal areas. At this time, the easterly wave disturbance at the bottom of the subtropical high provided the circulation background for extreme rainstorms.(2) The non-uniform heating near the ground provided sufficient thermal instability for the strong convection near the easterly wave trough, the surface mesoscale convergence line played an important role in triggering and strengthening the convection.(3) During the eastward movement of the boundary-layer warm moist air, a deep mesoscale vortex formed in east side of the Wuling mountains, which was the main reasons for the extreme rainstorm formation.(4) The topographic numerical sensitivity experiment further verified that the existence of the Wuling mountains was beneficial to the development and maintenance of strong convection on the east side of the mountain under the guidance of the easterly wind flow.

关 键 词：东风波 极端强降水 武陵山脉 地形敏感性试验 

分 类 号：P458.121.1[天文地球—大气科学及气象学]