2017年10月大气环流和天气分析

摘要

2017年10月环流特征如下:极涡呈偶极型,中高纬地区西风带为4波型分布,西太平洋副高强度较常年偏强、位置明显偏西.全国平均降水量46.2 mm,较常年同期(35.8 mm)偏多29％,为1961年以来第八高;全国平均气温10.6℃,较常年同期(10.3℃)偏高0.3℃.10月我国的大范围降水过程有6次,主要冷空气过程3次,其中8-10日降水过程伴随冷空气活动,给西北地区东部、华北中南部、东北南部带来该地区该季节较罕见的大范围强降水.2017年第20号台风卡努10月中旬登陆广东雷州半岛,给华南带来大风、降水.下旬我国北方出现一次雾-霾天气过程.%The main characteristics of the general atmospheric circulation in October 2017 are as follows.The polar vortex showed a dipole pattern.The circulation presented a four-wave pattern in middle-high latitudes.The northwestern Pacific subtropical high was stronger and remarkably more westward extended than normal.The monthly mean precipitation amount was 46.2 mm,which is 29％ more than normal (35.8 mm),ranking the top 8th since 1961.The monthly mean temperature was 10.6℃,0.3℃ higher than normal.There were six large-range heavy rainfall processes and three cold air processes over China,of which the rainfall process from 8 to 10 October was accompanied by cold airs,resulting a rarely-seen large-range heavy rainfall in Autumn over North China.On 16 October,Typhoon Khanun (1720) made landfall at Leizhou Peninsula,Guangdong,bringing gale and rainfall to South China.In late October northern China suffered a fog-haze event.