2017年11月大气环流和天气分析

摘要

2017年11月大气环流特征如下,北半球极涡呈偶极型分布;北半球中高纬度环流呈4波型分布,东亚大槽偏强,西太平洋副热带高压偏西偏强,南支槽平均位置位于90°E附近.11月全国平均降水量15.9 mm,较常年同期(18.8 mm)偏少15.3％,江南、华南雨日数多,全国共有58站次出现暴雨,12站日降水量超过月极大值.全国平均气温3.6℃,较常年同期(2.9℃)偏高0.7℃,全国有55站次日最高气温超过当月历史最高值,有7站日最低气温突破秋季历史最低值.月内,我国出现4次冷空气过程,3次较强降水过程,1次雾-霾天气过程.%The main characteristics of the general atmospheric circulation in November 2017 are as follows.There are two polar vortex centers in the Northern Hemisphere.The circulation in Eurasian middle-high latitudes showed a four-wave pattern.The East Asia major trough was stronger than normal.The northwestern Pacific subtropical high was stronger than normal,located more westward.The south branch trough was located around 90°E averagely.The monthly mean precipitation amount was 15.9 mm,which is 15.3％ less than normal.In November,precipitation was characterized by more rainy days in the south of the Yangtze River and Southern China.Torrential rainfall events occurred over 58 stations,and the daily rainfall amount of 12 stations exceeded the maximum records in November.Meanwhile,the monthly mean temperature was 3.6℃,which is 0.7℃ higher than normal.The daily maximum air temperature at 55 stations exceeded the historic high in November,and the daily minimum air temperature of 7 stations broke the lowest value in autumn in history.Four waves of strong cold air processes,three major rainfall processes and one fog-haze weather events occurred during this month.