2018年1月大气环流和天气分析

摘要

The main characteristics of the general atmospheric circulation in January 2018 are as follows. There were two polar vortex centers in the Northern Hemisphere.The circulation presented a four-wave pattern in middle-high latitudes.The East Asian trough behaved strongly.The monthly mean precipita-tion was 1 9.6 mm,48.4% more than normal.Besides,the activities of cold air strengthened,causing the monthly mean temperature (-5.3℃) to turn from higher than normal to lower,and the mean temperature became 0.3℃ lower than normal (-5.0℃).In this month,precipitation was strengthened with more rainfall than normal,and freezing rain and snow weather occurred in southern China and Shaanxi Province, similar to the freezing disaster in southern China in 2008.Fog-haze event appeared in this month only once,from 13 to 22 January 2018,but was characterized by the widest range,the longest duration and the maximum intensity in the winter of 2017.%2018年1月大气环流主要特征为:北半球极涡呈偶极型分布,环流呈四波型,东亚槽略偏强.1月,全国平均降水量19.6 mm,较常年同期(13.2 mm)偏多48.4%.1月冷空气势力明显加强,全国平均气温(-5.3℃)由较常年偏高转为偏低的状态,气温较常年同期(-5.0℃)偏低0.3℃.月内,降水偏多偏强,我国南方地区以及陕西关中等地出现较为少见的冰冻雨雪天气,与2008年出现的南方雪灾情况相似;1月仅有1次雾-霾天气过程,但2018年1月13—22日是2017年入冬以来范围最广、持续时间最长、强度最强的雾-霾天气过程.