2015年11月大气环流和天气分析

Analysis of the November 2015 Atmospheric Circulation and Weather

2015年11月环流特征如下：北半球极涡呈单极型分布,中高纬西风呈3波型分布,南支槽平均位置大致位于90°E附近,同时,西太平洋副热带高压较常年同期偏西、强度偏强。11月全国平均降水量39.4 mm,较常年同期偏多1.1倍;全国平均气温为4.1℃,较常年同期偏高1.2℃,但华北、东北等地气温偏低。月内共出现2次冷空气过程和4次主要降水过程,江南、华南等地部分地区雨量偏多2~3倍,多站出现极端日降水量;月内还有3次重污染天气过程。

The main characteristics of the general atmospheric cirulation in November 2015 are listed as fol lows： There is one polar vortex centre in the Northern Hemisphere. In the mid-high latitudes, the circula- tion presents a three-wave pattern. The average south branch trough is located around 90°E. The north- western Pacific subtropical high is stronger than normal, located more westward. Meanwhile, monthly mean precipitation amount is 39.4 mm, which is 1. 1 times more than its climatological mean. Monthly mean temperature is 4.1℃, being 1.2℃ higher than normal except the North and Northeast China. Two cold air processes and 4 severe rainfall events take place with extreme precipitation records observed at some stations in China. Moreover, the precipitation amount of Jiangnan, South China and other parts is 2 -3 times more than normal. In addition, three heavy pollution weather processes are experienced during