2009—2010年贵州秋、冬、春季干旱气象要素与环流特征分析

利用2009年9月—2010年5月贵州88个气象站地面观测资料,800个自动气象站温度、降水资料以及NCEP再分析资料,分析了持续干旱过程中的大尺度环流背景及气象要素分布特征,同时运用气候干湿指数、综合气象干旱指数对此次持续干旱程度进行了模拟。结果表明,贵州此次持续干旱天气主要发生在西太平洋副热带高压呈带状分布,强度偏强、位置偏西、南支系统偏弱及冷空气活动路径偏北偏东的环流条件下。在干旱期间,贵州西部地区气温为正距平,降水为负距平,空气相对湿度为38%～73%,气候干湿指数<0.6;东部地区气温除2009年11月和2010年4～5月为负距平外,其余月份均为正距平,降水基本上为负距平,空气相对湿度为60%～81%,除2009年11月和2010年4～5月气候干湿指数>1.0外,其余月份均<0.6。总体上,贵州西部地区的旱情较东部地区严重。

Analyses on Meteorological Elements and General Circulation of Drought in Guizhou Province in Autumn-Winter-Spring from 2009 to 2010

Based on the surface observation from 88 stations in Guizhou Province,air temperature and precipitation data from 800 automatic weather stations from September 2009 to May 2010,and NCEP reanalysis data,the large-scale circulation background and the meteorological element distribution features during persistent drought period were analyzed,and meanwhile,the degree of the drought was modeled through climate dry-wet index and comprehensive meteorological drought index.The results revealed: It was the west Pacific subtropical high becoming zonal distribution,intensified,westward,with south weaker synoptic system and the path of the cold air tending to more northward and eastward that caused persistent drought taking place in Guizhou.During the drought period in the west of Guizhou Province,the air temperature was positive anomaly,precipitation was negative anomaly,relative humidity was 38%～73%,and climate dry-wet index was less than 0.6.In the drought period of the east of Guizhou Province,the air temperature was positive anomaly except for Novenber 2009 and April～May 2010,Others were negative anomaly,precipitation was basically positive anomaly,relative humidity was 60%～81%,and climate dry-wet index was less than 0.6,except for November 2009 and April～May 2010,Others were more than 1.0.In general,the drought in the west of Guizhou was more severe than that in the east.