2012年5月大气环流和天气分析

2012年5月大气环流特征为:北半球极涡呈单极型,中心位于北地群岛附近,较常年偏强,中高纬环流多波动,引导多股冷空气影响我国;西太平洋副热带高压比常年同期略偏强,东亚大槽较常年同期明显偏强,南支槽位于90°E附近,较常年略偏强。2012年5月,全国平均气温为16.8℃,较常年同期(15.8℃)偏高1.0℃,与常年相比全国大部地区气温接近常年同期或偏高。全国平均降水量为66.1mm,较常年同期(64.4mm)略偏多2.63%。月内出现5次主要的降水过程。甘肃、湖南等地出现极端降水过程,云南干旱有所缓解。四川、云南、贵州和广西4省(区)出现极端高温天气;全国多个地区遭受风雹灾害。

Analysis of the May 2012 Atmospheric Circulation and Weather

The following are the main characteristics of the general circulation of atmosphere in May 2012: there is only one polar vortex center in the Northern Hemisphere with stronger strength than normal years.More troughs occur in middle-high latitudes in the Asian area,and lead to several cold air currents to influence China.The subtropical high is slightly stronger than normal years.The East Asia major trough is clearly stronger than usual at the same time period.The south branch trough at 90°E is slightly stronger than normal years.The monthly mean temperature averaged over China is 16.8℃,which is 1.0℃higher than the same period of normal years.The mean precipitation(66.1 mm) is 2.63%more than normal (64.4 mm).There are 5 precipitation processes in May 2012.Extreme precipitation events occur in Provinces Gansu and Hunan,and drought is mitigated in Yunnan.High temperature occurs in Sichuan, Yunnan,Guizhou and Guangxi.Strong wind and hail disasters hit many regions in China in May.