2019年2月大气环流和天气分析

Analysis of the February 2019 Atmospheric Circulation and Weather

2019年2月大气环流的主要特征是北半球极涡较常年同期偏强,中心偏向东半球,位置偏北;欧亚中高纬环流呈4波型,环流经向度总体较小。西太平洋副热带高压偏强;南支槽较常年偏弱、偏西。2月,我国冷空气活动较弱,仅出现一次大范围强冷空气和一次中等强度冷空气过程;全国平均气温为-1.3℃,较常年同期偏高0.4℃;东北地区北部气温异常偏高。月内,全国平均降水量为23.2mm,较常年同期偏多33.3%;南方出现持续阴雨天气,青藏高原降雪明显偏多,青海东南部出现雪灾。另外,下旬我国中东部地区出现持续雾-霾天气。

The main characteristics of the general atmospheric circulation in February 2019 are as follows.The polar vortex center in the Northern Hemisphere was stronger than normal and located by north in the Eastern Hemisphere.The circulation at middle-high latitudes of Eurasia showed a four-wave pattern,and the degree of meridionality was lower than normal generally.The Western Pacific subtropical high was strong relatively,and the Bay of Bengal trough was weaker and more to the west than normal.Cold air processes attacked China twice in February,one national-wide strong cold air process and one moderate cold air process.The monthly mean temperature was-1.3℃,higher than normal by 0.4℃.The temperature was abnormally high in Northeast China.The monthly mean precipitation amount was 23.2 mm,33.3%higher than normal.Also,one persistent rainy weather event happened in southern China.Snowfall hit the Tibetan Plateau frequently,causing snow disaster in southeastern part of Qinghai Province.In addition,continues fog-haze weather appeared in the central and eastern part of China in late February.