华西秋雨变异特征及其成因分析  

Varation Characteristics Causes of Autumn Rain in Westem China

作　　者：梅双丽 陈尚锋[2] MEI Shuangli;CHEN Shangfeng(National Meteorological Center,Beijing 100081,China;Center for Monsoon System Research,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China)

机构地区：[1]国家气象中心,北京100081 [2]中国科学院大气物理研究所季风系统研究中心,北京100029

出　　处：《高原气象》2022年第6期1492-1500,共9页Plateau Meteorology

基　　金：国家科技支撑计划项目(2015BAC03B06);中国气象局创新发展专项(CXFZ2021010)。

摘　　要：基于华西地区373站降水数据和美国国家环境预测中心/国家大气研究中心再分析资料研究了华西秋雨的变异特征,并分析了影响华西秋雨的主要环流系统及其作用机理。结果表明,华西秋雨存在显著的年际变化特征。当华西地区秋季降雨偏多时,在对流层低层菲律宾北部存在一个异常反气旋,该异常反气旋西部的异常南风为华西地区输送暖湿水汽(水汽源地位于阿拉伯海北部-印度半岛-孟加拉湾北部-中南半岛地区)。同时在对流层中层,欧洲地区往往存在一个阻塞高压,巴湖附近受低槽控制,此环流配置有利于冷空气向南爆发到达华西地区。在对流层高层,欧亚中高纬地区存在一个显著的大气环流遥相关,该大气环流遥相关对欧洲地区的阻塞高压和巴湖附近的低压槽以及东亚环流形势的维持和发展有重要作用。进一步分析表明,菲律宾和台湾岛附近以及赤道南印度洋上的受抑制的对流活动对菲律宾北部异常反气旋的维持有重要作用。当华西地区秋季降雨偏少时,情况则往往相反。本研究结果加深了华西秋雨年际变异特征和机理的认识并对进一步提高其预测水平具有一定的应用价值。Based on 373 stations precipitation data in West China and National Centers for Environmental Prediction/National Center for Atmospheric Research(NCEP/NCAR)reanalysis data,variation characteristics of autumn rain in Western China are investigated,and associated atmospheric circulation systems affecting autumn rain in Western China and their interactiovemechanism are explored in this study. The results show that there are significant interannual variation characteristics of autumn rain in Western China. When more rainfall occurs in autumn in West China,there is an abnormal anticyclone at the low troposphere over the northern Philippines,and the associated southerly wind anomalies to the west side of this anticyclone anomaly carry warmer and wetter water vapor from northern Arabian Sea-Indian Peninsula-northern Bay of Bengal-China Peninsula to Western China.At the same time,the positive geopotential height anomaly,representing enhanced blocking activities,is observed over Europe,and the negative geopotential height anomaly,indicating enhanced low trough,is observed near Lake Balcosh in the middle troposphere. Therefore,this anomalous circulation configuration is conducive to the outbreak of cold air from higher latitude southward to West China. A clear atmospheric circulation teleconnection which plays an important role in the maintenance and development of blocking high in Europe and low-pressure trough near Lake Balcosh as well as circulation anomalies over East Asia,is seen over mid-high latitudes of Eurasia in the upper troposphere. Further analysis shows that the suppressed convection activities near the Philippines and Taiwan Island and the southern equatorial Indian Ocean play an important role in the maintenance of the anomalous anticyclone in the northern Philippines. On the other hand,when there is less rainfall in autumn in West China,the Eurasian wave train anomaly causes the positive height potential anomaly in Balkash Lake,which is not conducive to the establishment of low trough and the activity of c

关 键 词：华西秋雨 年际变化 热带对流 波列 

分 类 号：P446.40[天文地球—大气科学及气象学]