2016年5月大气环流和天气分析

Analysis of the May 2016 Atmospheric Circulation and Weather

北半球极涡呈偶极型分布,极涡主体分别位于格陵兰岛以西以及贝加尔湖北部附近,强度较常年同期偏强;中高纬环流呈4波型分布特征,长波槽分别位于北美西部、格陵兰岛东部、里海西部和贝加尔湖北部;西太平洋副热带高压较常年同期面积明显偏大,588 dagpm等高线东西伸展经度跨度很大,接近环绕全球。5月全国平均气温16.3℃,较常年同期(16.2℃)偏高0.1℃;全国平均降水量82.8 mm,较常年同期(69.5 mm)偏多19.1%。月内我国主要天气特点是:南海夏季风5月下旬爆发;西南地区东部、江南、华南南暴雨过程频发;强对流过程影响范围广、过程强度大、雷暴大风和冰雹灾害较多。

The main characteristics of the general atmospheric circulation in May 2016 were as follows;The circulation of polar vortex in the Northern Hemisphere was in a dipole pattern.The 500 hPa geopotential height presented the distribution of a four-wave pattern in the mid-high latitude of the Northern Hemisphere.The subtropical high of Northwest Pacific extended to more westward than usual with larger area,almost circling the globe.The monthly mean temperature was 16.3°C,being 0.1°C higher than normal.The monthly mean precipitation amount was 82.8 mm,19.1%more than the usual average（69.5 mm）.The main weather characteristics in this month were that the onset of South China Sea summer monsoon happened in the last dekad of May;torrential rainfalls were seen frequently in the east of Southwestern China,the south of Southern China and South Yangtze River;and severe convective weather happened widely with greater intensities and severe thunderstorms and hail disaster.