青藏高原东南缘攀枝花市降水特征及其成因初探  

Characteristics and genesis of precipitation in Panzhihua on the southeast margin of Qinghai-Tibet Plateau

作　　者：李永军 卢萍 LI Yongjun;LU Ping(State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081;Institute of Plateau Meteorology,China Meteorological Administration,Chengdu 610072;Heavy Rain and Drought-Flood Disasters in Plateau Basin Key Laboratory of Sichuan Province,Chengdu 610072;Panzhihua Meteorological Observatory,Panzhihua 617000)

机构地区：[1]中国气象科学研究院灾害天气国家重点实验室,北京100081 [2]中国气象局成都高原气象研究所,成都610072 [3]高原与盆地暴雨旱涝灾害四川省重点实验室,成都610072 [4]攀枝花市气象台,攀枝花617000

出　　处：《暴雨灾害》2024年第1期101-109,共9页Torrential Rain and Disasters

基　　金：四川省自然科学基金项目(2022NSFSC0021);国家重点研发计划项目(2022YFC3003902);中国气象科学研究院灾害天气国家重点实验室开放课题项目(2021LASW-A06);攀枝花市市级指导性科技计划项目(2022ZD-S-6)。

摘　　要：为更好地认识青藏高原东南缘地形复杂区降水特征及其成因,利用位于青藏高原东南缘的攀枝花市2015—2020年72个国家、区域气象观测站资料和欧洲中心0.25°×0.25°分辨率的ERA5再分析资料,对攀枝花降水特征及成因进行分析。结果表明:(1)攀枝花降水具有地形作用突出、北多南少的特点,降水日数是造成降水空间分布差异的主要原因之一。(2)攀枝花夜雨特征显著,呈单峰型,降水峰值出现在03时(北京时),因攀枝花位于干热河谷区,日间湿度小、夜间湿度大,夜间较饱和的大气更容易凝结,触发降水,湿度的日变化是攀枝花易发生夜雨的原因之一。(3)攀枝花干湿季分明,6—10月为攀枝花湿季,11月至次年5月为攀枝花干季,6月和10月是干湿转换的过渡期。6月孟加拉湾西南季风爆发,攀枝花雨季开始,干季逐渐结束;10月干燥的高原南支西风气流加强,雨季趋于结束,干季开始。To enhance our comprehension of the precipitation patterns and underlying causes in the complex terrain area of the southeastern edge of the Qinghai Tibet Plateau,the observation data of 72 automatic weather stations in this area and the ERA5 reanalysis data with a res⁃olution of 0.25°×0.25°obtained from the European Center between 2015 and 2020 were utilized to analyze the precipitation characteristics and genesis in Panzhihua.The results indicate that:(1)The precipitation in Panzhihua exhibits a prominent topographic effect,showing a sig⁃nificant decrease from north to south in annual precipitation distribution.The number of precipitation days is one of the main factors for the spatial distribution difference in precipitation.(2)Panzhihua displays obvious nighttime rain features,which shows a unimodal pattern,with the peak precipitation occurring at 03∶00 BT.Panzhihua is located in a dry and hot valley area,and thus experiences low daytime humidity and high nighttime humidity.The saturated atmosphere at night is more likely to lead to condensation,resulting in precipitation.The diurnal variation of humidity is one of the reasons why nighttime rain prevails in Panzhihua.(3)Panzhihua has distinct dry and wet seasons,with June to October being the wet season,November to May of the following year being the dry season,and June and October being the transition period between dry and wet.In June,the southwest monsoon breaks out in the Bay of Bengal,and the rainy season begins in Panzhihua,grad⁃ually the dry season finishes.In October,the dry southern branch of the plateau's westerly airflow strengthens,and the rainy season tends to end and the dry season begins.

关 键 词：青藏高原 降水特征 南亚高压 西南季风 南支绕流 

分 类 号：P426.614[天文地球—大气科学及气象学]