夏季高原低涡切变影响下云南大雨暴雨的分布及成因研究  

Distribution and Genesis of Heavy Rain over Yunnan Affected bythe Plateau Low Vortex Shear in Summer

作　　者：黄慧君 郑建萌[1,3] 马涛 张万诚 何钰[1,5] 朱莉 HUANG Huijun;ZHENG Jianmeng;MA Tao;ZHANG Wancheng;HE Yu;ZHU Li(Research Center for Disastrous Weather in Hengduan Mountains,China Meteorological Administration,Kunming 650034,Yunnan,China;Meteorological Bureau of Dali Prefecture of Yunnan Province,Dali 671000,Yunnan,China;Yunnan Climate Center,Kunming 650034,Yunnan,China;Yunnan Institute of Meteorological Sciences,Kunming 650034,Yunnan,China;Yunnan Meteorological Observatory,Kunming 650034,Yunnan,China)

机构地区：[1]中国气象局横断山区低纬高原灾害性天气研究中心,云南昆明650034 [2]云南省大理州气象局,云南大理671000 [3]云南省气候中心,云南昆明650034 [4]云南省气象科学研究所,云南昆明650034 [5]云南省气象台,云南昆明650034

出　　处：《高原气象》2023年第2期403-416,共14页Plateau Meteorology

基　　金：国家自然科学基金项目(41765003,42075013,41665005);第二次青藏高原综合科学考察研究项目(2019QZKK0105);中国气象局创新发展专项(CXFZ2022P041,CXFZ2022P042,CXFZ2022P019)。

摘　　要：利用中国气象局MICAPS系统历史天气图、云南125个站点逐日气象观测资料、欧洲中心ERA Interim资料,对1991-2018年夏季高原低涡切变造成云南大雨暴雨过程的气候特征进行了统计分析,结果表明:(1)夏季高原低涡切变影响云南,大雨暴雨平均每年出现12次,出现次数整体呈减少趋势,具有明显的年际变化特征;1998年出现最多达25次,2010年最少。高原低涡切变影响云南最多的是6月,平均为5次,其次是7月。(2)高原低涡切变可以造成云南全省性的大雨以上降水过程,从影响区域来看,主要分布在滇西北、滇西、滇中及以东地区,滇西北的东部是多发区,最多位于丽江东部至昆明,以及哀牢山附近;(3)产生全省性暴雨过程的合成特征主要是西太平洋副热带高压(以下简称西太副高)强度较弱,滇缅之间维持弱脊区,高原低涡切变容易从四川西北部边缘南移影响云南,受高原低涡切变影响云南出现暴雨的水汽主要来自孟加拉湾和部分来自高原,两支水汽在云南汇合,为暴雨的产生提供充足水汽。(4)2014年8月初的全省性大雨的天气系统主要是高原低涡切变与700 hPa切变线共同影响造成;中低层的正螺旋度远大于高层的负螺旋度,说明中低层正涡度辐合上升运动高于高层负涡度辐散,这为强降雨的产生提供了强大的动力条件。研究表明700 hPa湿螺旋度水平分布对高原低涡切变影响造成的强降水落区有指示意义。Based on the historical weather map of MICAPS made by China Meteorological Administration,the daily meteorological observation data from 125 stations in Yunnan Province,and ERA-interim data,the climatic characteristics of heavy rainfall processes caused by Plateau vortex shear in summer from 1991 to 2018 in Yunnan province were statistically analyzed.The main results are as follows:(1)The Plateau vortex shear affects Yunnan in summer,and heavy rain occurs 12 times a year on average.The frequency of heavy rain decreases with obvious interannual variation.There were as many as 25 cases in 1998 and the least in 2010.The Plateau vortex shear affects Yunnan most frequently in June with an average of 5 times,followed by July.(2)The plateau vortex shear can cause consistent heavy rainfall in Yunnan.From the perspective of the affected area,it is mainly distributed in the northwest Yunnan,western Yunnan,central Yunnan and east Yunnan,and the eastern part of northwest of Yunnan is also a frequent area,most of which is located in the east of Lijiang to Kunming and the vicinity of Ailao Mountain.(3)The characteristics of atmospheric circulation causing heavy in Yunnan are mainly that the western Pacific subtropical high strength is weak,the weak ridge maintains between Burma area,the plateau low vortex shear easily effects the area from the northwestern margin of Sichuan to Yunnan,the water vapor is mainly from the Bay of Bengal and some from the plateau,and convergence in Yunnan for the heavy rainfall by providing sufficient moisture.(4)The weather system of heavy rain in early August 2014 was mainly caused by the Plateau vortex shear and 700 hPa shear line.The positive helicity of the middle and lower layers is much larger than the negative helicity of the upper layers,indicating that the positive vorticity convergence and upward movement in the middle and lower layers is higher than the negative vorticity divergence in the upper layers,which provides a powerful dynamic condition for the generation of heavy rainfall.The r

关 键 词：高原低涡切变 大雨暴雨 分布特征 滇缅高压 云南 

分 类 号：P443[天文地球—大气科学及气象学]