2022年9月大气环流和天气分析

Analysis of the September 2022 Atmospheric Circulation and Weather

2022年9月大气环流主要特征为北半球极涡呈单极型分布且较常年同期强度偏弱,欧亚地区中高纬环流以纬向环流为主,呈弱的“两槽一脊”形势,西太平洋副热带高压较常年偏东偏强。9月,全国平均气温为17.9℃,较常年同期(16.9℃)偏高1.0℃;全国平均降水量为49.4 mm,较常年同期(65.3 mm)偏少24%。月内我国出现4次暴雨天气过程,过程降水强度强,多站降水量突破历史极值。月内共有7个台风在西北太平洋和南海生成,生成个数较常年偏多,其中仅有2212号强台风梅花4次登陆我国,登陆个数偏少,另外,2216号超强台风奥鹿影响我国南海及华南地区。月内,长江中下游地区持续少雨,导致该地中度及以上等级气象干旱持续。

The main characteristics of the general atmospheric circulation in September 2022 are as follows.There was a single polar vortex center in the Northern Hemisphere and it was weaker than normal.The circulation at the mid-high latitudes of the Eurasian was mainly dominated by zonal circulation,presenting a weak“two troughs and one ridge”situation.The western pacific subtropical high was stronger than that of the climatological normal,located eastward compared to that in the same period of normal years.The monthly mean temperature was 17.9℃,higher than normal(16.9℃)by 1.0℃.The monthly mean precipitation was 49.4 mm,24%less than normal(65.3 mm).During this month,China had four torrential rain processes with strong precipitation intensities and at many stations the rainfall surpassed the historical records.Seven typhoons formed over the western North Pacific and the South China Sea in September,but only one of them,i.e.,the Severe Typhoon Muifa(No.2212),made landfall four times in China.Then,the Super Typhoon Noru(No.2216)affected the South China Sea and the South China Region.So,the number of generated typhoons was higher than normal,but the landing typhoons were fewer.In addition,the continuous lack of rain in the middle and lower reaches of Yangtze River led to sustained drought above moderate magnitude.