2014年6—7月湖北地区干旱特征及其异常环流分析

Drought Characteristics and Abnormal Circulation in Hubei Province from June to July in 2014

2014年6—7月湖北月降水距平分别为-40.1%和-23.6%,但温度距平大部地区为负。采用1981—2014年湖北省76个地面气象站逐月降水资料和NCEP/NCAR再分析资料,分析了6—7月湖北地区干旱的气候特征及2014年6—7月的异常环流。结果表明:2014年6—7月南亚高压东扩加强,西太平洋副高总体偏南,同时北方冷空气势力偏弱,中纬度地区环流平直,不利于引导南北方冷暖空气在湖北交汇形成降水;西太平洋台风对我国的影响区域偏南,湖北受台风顶部东北气流影响,水汽通量辐散;低层切变线和西南涡活动偏弱,不利于水汽辐合。

The monthly precipitation anomalies in Hubei province were-40.1%and-23.6%in June and July 2014,respectively,but the temperature anomalies were negative in most areas.Based on the monthly precipitation data of 76 meteorological stations in Hubei province and the NCEP/NCAR reanalysis data,the climatic characteristics of drought in Hubei province and the anomalous circulation are analyzed from June to July in 2014.Results showed that the South Asia high was eastward expansion and strengthened,the western Pacific subtropical high was generally southward,and the cold air was weak at the same time.The circulation of the mid-latitude region was straight,which was not conducive to the formation of precipitation by the intersection of warm and cold air in Hubei province.Typhoon influence area was the south of China,and water vapor flux was divergence in Hubei province caused by northeast air flow at the top of typhoon.Low-level shear line and southwest eddy was weak,which was not conducive to water vapor convergence.