气象2018，Vol.44Issue(4)：572-581,10.DOI:10.7519/j.issn.1000-0526.2018.04.011
2017年秋季我国北方地区降水异常偏多成因分析
Analysis of Characteristics and Causes of Precipitation Anomalies over Northern China in Autumn 2017
摘要
Abstract
The stage characteristics of precipitation over China in the autumn of 2017 is obvious,and the significantly above-normal precipitation over northern China from September to October was mainly influ-enced by the East Asia circulation pattern anomaly.The distribution of 500 hPa height anomaly field in East Asia was "+-+" from high to low latitude.The polar height field was higher than normal,the po-lar vortex split and inclined to Northeast Asia,the area between Baikal Lake and Balkhash Lake was under a significantly low trough,and the West Pacific subtropical high was stronger,stretching more westward and northward than normal,which is favorable to the intensive autumn rainfall in West China.In addition, anticyclonic circulation anomaly over Korean Peninsula was conducive to guiding the cold and wet airflow along the easterly path to the area between the Yellow River and the Yangtze River,and to converging with the warm and wet airflow from the Bay of Bengal and the South China Sea.The water vapor flux con-vergence resulted in precipitation anomalies in the Huanghuai and Jianghuai regions.Further diagnosis shows that the tropical Middle East Pacific sea surface temperature turned cold in autumn,and the Walker circulation in the tropical Pacific increased obviously,which is beneficial to the westward and northward extension of the stronger West Pacific subtropical high.The positive phase of the tropical Indian Ocean di-pole in September-October was favorable for the formation of anticyclonic circulation anomalies in the Bay of Bengal,and also beneficial to the westward and northward extension of the West Pacific subtropical high.Therefore,the influence of the external forcing signal of sea surface temperature and the circulation anomaly in the middle and high latitudes over East Asia led to more precipitation over northern China.关键词
秋季降水/北方地区/西太平洋副热带高压/海温异常Key words
autumn precipitation/northern China/West Pacific subtropical high/sea surface temperature anomalies分类
天文与地球科学引用本文复制引用
支蓉,陈丽娟,竺夏英..2017年秋季我国北方地区降水异常偏多成因分析[J].气象,2018,44(4):572-581,10.基金项目
国家自然科学基金面上项目(41575074)、国家重点基础研究发展计划(973计划)(2015CB453203)和国家自然科学基金重点项目(41730964)共同资助 （41575074）
