华东地区一次高空冷平流强迫型强对流分析  

Analysis of a Severe Convection Forced by High-Altitude Cold Advection in East China

作　　者：王芳 沈杭锋[1] 樊李苗 高梦竹 汪子琪 WANG Fang;SHEN Hangfeng;FAN Limiao;GAO Mengzhu;WANG Ziqi(Hangzhou Meteorological Bureau,Hangzhou 310051;Heilongjiang Meteorological Observatory,Harbin 150001;Jinhua Meteorological Office of Zhejiang Province,Jinhua 321000)

机构地区：[1]杭州市气象局,杭州310051 [2]黑龙江省气象台,哈尔滨150001 [3]浙江省金华市气象局,金华321000

出　　处：《气象》2024年第7期818-834,共17页Meteorological Monthly

基　　金：中国气象局预报员专项(CXFZ2021Z033);浙江省气象局一般科技项目(2021YB19、2022YB13);浙江省气象局青年科技项目(2023QN19)共同资助。

摘　　要：利用常规气象观测资料、区域自动气象站加密观测资料和GFS 0.25°×0.25°逐6 h的分析场数据以及多普勒雷达、FY-4卫星等资料,对2020年4月12日华北冷涡后部中低层一致西北气流背景下,在华东地区出现的大范围对流大风天气进行了诊断分析。结果表明,12日上午冷空气大风南下之后,下午华东处于中层冷平流、低层暖平流的有利热力背景条件下,在850 hPa与500 hPa温差大值区内,由山东、江苏交界一带的干线触发了对流;对流系统在东移南压过程中因水汽条件转好、中层风速增强、阵风锋的合并及杭州湾特殊海陆分布等有利条件下明显加强,使得江苏、安徽东南部、浙江北部等地在冷空气大风之后再次出现了大范围对流大风天气,并在舟山群岛附近出现13级极端大风;其灾害性大风出现在对流系统回波缺口处及其东北侧回波附近,由后侧入流急流及风暴内强烈的下沉辐散、光滑下垫面、快速移动的对流系统以及系统内小尺度下击暴流叠加造成。A large-scale convective gale event was studied based on conventional observation data,automa-tic weather station data,6 h GFS analysis data with 0.25°×0.25°spatial resolution,Doppler radar data,and FY-4 satellite data in East China on 12 April 2020 under the background of consistent northwesterly air flow from the lower to the middle layer behind the North China cold vortex.The results demonstrate that after the strong cold air gales moved southward on the morning of the 12 April,a convective storm was triggered near the drylines at the junction of Shandong and Jiangsu provinces in the afternoon under the favorable thermal background of cold advection at the middle level and warm advection at the lower level.The convective storm occurred in the area with a large temperature difference between 850 hPa and 500 hPa.The convective system was strengthened with favorable conditions such as better water vapor condition,stronger wind speed in the middle layer,merged gust front and the influence of the special land and sea distribution in Hangzhou Bay,which caused the large-scale convective gale weather in Jiangsu,southeastern Anhui and northern Zhejiang again,and the extreme gales at scale 13 near the Zhoushan Islands.The extreme gales occurred at gaps in the convection system and near the northeast side,caused by the rear inflow jet and the intense downdraft,smooth underlying surface,fast-moving convection system and small-scale downburst currents within the system.

关 键 词：冷流强迫 干线 加强机制 极端大风 

分 类 号：P458[天文地球—大气科学及气象学]