2017年9月大气环流和天气分析

Analysis of the September 2017 Atmospheric Circulation and Weather

2017年9月大气环流的主要特征是极涡强度接近常年,欧亚大陆中高纬环流呈多波型,西太平洋副热带高压明显偏西偏南,强度接近常年。9月全国平均降水量62.0 mm,较常年同期(65.3 mm)偏少5%;全国平均气温为17.8℃,较常年同期偏高1.2℃,为1961年以来第一高。月内主要出现了10次区域性强降水过程。9月在西北太平洋和南海共有4个台风生成,其中1716号台风"玛娃"在我国广东省登陆。月内四川、云南部分地区秋雨明显,全国13个省(市、区)遭受风雹灾害,内蒙古中东部旱情持续缓和。

The main characteristics of the general atmospheric circulation in September 2017 are as follows. There was one polar vortex center in the Northern Hemisphere, slightly stronger than usual. The circula- tion in Eurasian middle-high latitudes showed a multi-wave pattern. The subtropical high in northwest Pacific Ocean lay westward and southward, and its intensity was slightly stronger than its average state during the corresponding period of normal years. The monthly mean precipitation amount is 62.0 mm which is less than normal in 5%, while the monthly mean temperature is 17.8℃, 1.2℃ higher than normal, which ranks the highest since 1961. Ten regional torrential rainfall events happened in September. Four tropical cyclones were generated over northwest Pacific Ocean and the South China Sea, and typhoon Mawar （1716） made landfall along the coastal areas over Guangdong Province in September. Sichuan and Yunnan received autumn rain notably; strong wind and hail disasters hit 13 provinces; drought situation in middle and eastern parts of Mongolia got relieved.