云贵高原中部倒春寒特征及其极端类型大气环境场分析  

Analysis of Characteristics of Late Spring Cold and Atmospheric Environment Field of Extreme Types in the Centre of Yunnan-Guizhou Plateau

作　　者：肖艳林 池再香 夏阳 严锐 孙翔 毛春旭 陈金梅 XIAO Yanlin;CHI Zaixiang;XIA Yang;YAN Rui;SUN Xiang;MAO Chunxu;CHEN Jinmei(Liupanshui Meteorological Bureau,Liupanshui 553000,China;Guizhou Institute of Mountainous Environment and Climate,Guiyang 550002,China)

机构地区：[1]六盘水市气象局,贵州六盘水553000 [2]贵州省山地环境气候研究所,贵州贵阳550002

出　　处：《沙漠与绿洲气象》2024年第2期123-131,共9页Desert and Oasis Meteorology

基　　金：六盘水市科技计划项目(52020-2021-NK-03);中国气象局预报员专项项目(CMAYBY2016-066);贵州省气象局科研业务登记项目([2020]06-19号)。

摘　　要：利用1981—2021年云贵高原中部45个气象观测站逐日平均气温资料,以及NCEP2.5°×2.5°再分析日资料,采用倒春寒指数计算、分级以及合成分析等方法,分析云贵高原中部倒春寒天气年际、年代际变化特征,并确定特重级倒春寒年和无倒春寒年为倒春寒极端类型年,对比分析其环流特征,找出其预报指标。结果表明:(1)1981—2021年云贵高原中部区域年度倒春寒标准化指数总体呈下降趋势,且在1998年前后具有一个明显的突变(α=0.01)。特重级和重级倒春寒年基本发生在20世纪80年代和90年代,进入21世纪后,以轻级倒春寒年和无倒春寒年为主。(2)在特重级倒春寒年,500 hPa极涡偏强,亚洲中高纬呈现出西高东低的异常环流型,有利于东亚地区环流径向度加大,同时50°N以南温度基本呈负距平分布,表明冷空气活动异常活跃,从而造成地面云贵准静止锋偏强。与此同时,700 hPa云贵高原受异常气旋式环流东侧的偏东气流控制,与华北异常反气旋式环流底部的偏东气流在云贵高原上空辐合,将南海和东海的水汽向云贵高原上空输送,有利于低温和降水天气的形成。在无倒春寒年,上述形势相反。(3)在特重级倒春寒年,前期夏季、秋季、冬季和同期春季中东太平洋海温均表现为东部型厄尔尼诺;在无倒春寒年,均表现为中部型厄尔尼诺。Based on the data of 45 conventional daily average temperature data,and reanalysis data(2.5°×2.5°)in the centre of Yunnan-Guizhou Plateau from 1981 to 2021,using the calculation and classification of late spring cold index,composite analysis and so on,we analyzed the interannual and interdecadal variation characteristics of cold late spring in the central Yunnan-Guizhou Plateau,selected the extremely heavy grade and non-grade late of spring cold years as extreme types,then made contrastive analysis of the circulation characteristics in order to explore forecast indicators.Results showed that:(1)The regional annual standardization index of late spring cold in the centre of Yunnan-Guizhou Plateau showed a downward trend from 1981 to 2021,and it had a very obvious mutation of late spring cold index around 1998(α=0.01).The extremely heavy grade and the heavy grade of late spring cold years basically occurred in the 1980s and 1990s,respectively.The light grade and no grade late spring cold years mainly occurred in the 21st.(2)The polar vortex was above-normal on 500 hPa in extremely heavy grade years.It presented an abnormal circulation pattern with high in the west and low in the east.It was helpful for increasing the circulation radial degree in East Asia.The temperature in the south of 50°N was basically negative anomaly distribution,indicating that the cold air activity was extremely active,resulting in a strong quasi-static front on the ground.At the same time,it was controlled by the easterly airflow at the east side of the anomalous cyclonic circulation on Yunnan-Guizhou Plateau at 700 hPa,and it converged with the easterly airflow at the bottom of the anomalous anti-cyclonic circulation in North China over the Yunnan-Guizhou Plateau,it was helpful for transferring water vapor from the South China Sea and the East China Sea to the Yunnan-Guizhou Plateau,thus facilitating the formation of low temperature and precipitation weather.While the above situation was opposite in the year of non-grade late spring co

关 键 词：倒春寒标准化指数 极端类型 云贵准静止锋 环流 海温 

分 类 号：P458.12[天文地球—大气科学及气象学]