2016年2月大气环流和天气分析

摘要

The main characteristics of the general atmospheric circulation in February 2016 are as follows:There are two polar vortex centers in the Northern Hemisphere.The circulation presents meridional pat-terns in middle-high latitudes.The south branch trough behaves actively,and the mean position is located at 90°E nearby.The subtropical high is a little weaker than normal years,and the average south branch trough is also weaker than normal years.The monthly mean precipitation is 12.3 mm,and 29.4% less than normal (1 7 .4 mm ).The monthly mean temperature is -1 .6℃,and 0 .1℃ higher than normal (-1 .7℃).There is one cold wave process nationwide.Meanwhile,sand-dust weather first appeared in Northwest China this year.%提2016年2月大气环流的主要特征是北半球极涡呈偶极型分布，中高纬环流经向度大；太平洋副热带高压接近常年同期或偏强，南支槽较常年同期偏弱，不利于水汽向我国输送。2月全国平均降水量12．3 mm，较常年同期（17．4 mm）偏少29．3％，全国平均气温－1．6℃，接近常年同期（－1．7℃）。月内，我国中东部大部地区出现一次寒潮天气过程；西北地区出现今年首次沙尘天气过程。