一次变形场背景下的暴雨位涡诊断研究  

Potential Vorticity Diagnose on a Heavy Rainstorm under Deformation Field

作　　者：裴坤宁 王磊 李谢辉 陈得圆 PEI Running;WANG Lei;LI Xiehui;CHEN Deyuan(Plateau Atmosphere and Environment Key Laboratory of Sichuan Province,School of Atmospheric Sciences,Chengdu University of Information Technology,Chengdu 610225,Sichuan,China)

机构地区：[1]成都信息工程大学大气科学学院高原大气与环境四川省重点实验室

出　　处：《高原气象》2019年第6期1221-1228,共8页Plateau Meteorology

基　　金：四川省科技厅软科学研究项目(2017ZR0043);青藏高原第二次综合科学考察任务1专题5;国家自然科学基金项目(41275033)

摘　　要：利用中国自动气象站与CMORPH融合的逐时降水资料和NCEP逐6 h再分析资料,从等熵位涡的角度对豫北地区2016年7月8日夜到9日上午在一次变形场背景下的暴雨天气过程做分析和研究。结果发现:(1) 7月8日20:00(北京时,下同)至9日08:00,随着高位涡和冷空气的逐渐东移,豫北位涡值变大,干冷空气与暖湿空气相遇使豫北地区有降水生成。而后9日14:00由于高位涡的继续东移以及台风的登录,致使豫北地区位涡变小,台风强度变弱,进而降水减弱。(2) 7月9日02:00-08:00,111°E附近上空的高位涡向东向下传输,使豫北暴雨区上空位涡增大,同时地面存在强水汽辐合,其辐合最大值位于900 h Pa高度上的太行山迎风坡处。另外,9日08:00豫北暴雨区从对流层高层400 h Pa至地面有次级环流生成,其上升支对应豫北暴雨区。(3)位涡收支方程诊断分析表明,9日08:00在500 h Pa高度上豫北暴雨区的局地位涡增加,主要来自水平平流的贡献。Rainstorm under a background of deformation field occurred in northern Henan from the night of 8 July2016 to the next morning. We studied the process from the perspective of potential vorticity with Hourly precipitation data from China automatic meteorological station and CMORPH fusion and NCEP ’s six-hour reanalysis data. The results show that as the high potential vorticity and cold air move to the southeast the potential vorticity values in north of Henan increase gradually from 20: 00 on 8 July to 08: 00 on 9 July. The meeting of dry cold air and warm wet air causes the heavy rainfall. When the potential vorticity in northern Henan has decreased and typhoon has weakened,the rainfall attenuates consequently due to the continuous eastward movement of the high potential vorticity and the landing of the typhoon at 14: 00 on 9 July. The high potential vorticity near 111°E is transmitted eastward and downward,which increases the potential vorticity over the rainstorm area from 02: 00 to 08: 00 on July 9.Meanwhile,there is strong water vapor convergence on the surface. The maximum value is located at the upwind slope of Taihang Mountain at the height of 900 hPa. In addition,secondary circulation forms from 400 hPa to surface over rainstorm area and the rising branch corresponds to the rainstorm area. The diagnostic analysis of the potential vortity budget equation shows that the local potential vorticity in the rainstorm area at the height of 500 h Pa at 08: 00 on July 9 increases,and only the horizontal potential vorticity advection provides a positive contribution.

关 键 词：变形场 等熵位涡 暴雨 豫北 

分 类 号：P458.3[天文地球—大气科学及气象学]