2021年9月大气环流和天气分析

Analysis of the September 2021 Atmospheric Circulation and Weather

2021年9月大气环流主要特征是:极涡呈单极型,中高纬度地区西风带呈3波型分布,西太平洋副热带高压较常年位置偏西。全国平均降水量为83.8 mm,较常年同期(65.2 mm)偏多28.5%;全国平均气温为18.2℃,较常年同期(16.6℃)偏高1.6℃。9月我国大范围降水过程有4次,西南、华北和东北等地出现强降水,局地灾情严重。9月在西北太平洋和南海共有4个台风生成,没有台风登陆我国。月内,西南地区东部、西北地区东部至华北、黄淮等地遭受暴雨洪涝灾害;华西地区秋雨开始时间偏早,雨量大;西北地区气象干旱缓解,华南气象干旱持续;南方出现阶段性高温,部分地区遭受旱灾。

The main characteristics of the general atmospheric circulation in September 2021 are as follows.The polar vortex showed a single-pole pattern.The circulation presented a three-wave pattern in middle-high latitudes.The northwestern Pacific subtropical high extended remarkably more westward than normal.The monthly mean precipitation amount was 83.8 mm,which is 28.5%more than normal(65.2 mm).The monthly mean temperature was 18.2℃,1.6℃higher than normal.Four large-range heavy precipitation processes occurred over China,of which Southwest China,North China and Northeast China were caught by severe precipitation,and some local areas suffered from serious disasters.Four typhoons were generated over northwestern Pacific Ocean and the South China Sea,but none landed on China.The east of Southwest China,the east of Northwest China to North China,the Huanghuai Region and other places suffered from torrential rain and flood disasters.Autumn rain in West China came earlier than normal and were stronger.The meteorological drought in Northwest China eased but continued in South China.Periodic high temperatures occurred in the south of China with some areas experiencing drought.