2020年11月大气环流和天气分析

2020年11月大气环流的主要特征为:北半球极涡呈偶极分布,环流呈三波型,东亚大槽偏弱,南支槽偏弱,西太平洋副热带高压偏西偏强。全国平均降水量为16.9 mm,比常年同期(19.0 mm)偏少11%,月内17—19日出现了一次强雨雪天气过程,湖北恩施建始县和辽宁丹东出现大暴雨,黑龙江牡丹江、鸡西和七台河、内蒙古通辽和赤峰等地出现大暴雪或特大暴雪。全国平均气温为3.9℃,比常年同期(2.9℃)偏高1℃,11月共出现4次冷空气过程,其中1次为全国强冷空气过程(18—22日)。10—17日,大气扩散条件较为不利,华北中南部、黄淮西部、汾渭平原等地发生一次雾-霾天气过程。

Analysis of the November 2020 Atmospheric Circulation and Weather

The main characteristics of the general atmospheric circulation in November 2020 are as follows.There were two polar vortex centers in the Northern Hemisphere.The circulation presented a three-wave pattern in mid-high latitudes.The East Asian trough and the southern branch trough were weaker while the western Pacific subtropical high was stronger,located more westward.The monthly mean precipita-tion over China was 16.9 mm,which is 11%less than normal(19.0 mm).One severe rain and snow process occurred from the 17 to 19 November,during which Enshi of Hubei Province and Dandong of Liao-ning Province experienced severe rainstorm,and Mudanjiang,Jixi and Qitaihe of Heilongjiang Province and Tongliao and Chifeng of Inner Mongolia were hit by severe snowfall or extremely severe snowfall.The monthly mean temperature was 3.9℃,1℃higher than normal(2.9℃).During this month,there were four cold air processes,one of which was nationwide from the 18 to 22 November.Additionally,as the result of unfavorable diffusing condition of atmosphere,one fog-haze event appeared in centralsouthern part of North China,west of Huanghuai Region,and Fenwei Plain during 10 to 17 November 2020.