干旱地区农业研究Issue(4)：237-244,256,9.
川渝地区夏季干旱气候特征及成因分析
Analysis of climatological characteristics and causes of summer droughts in Sichuan-Chongqing region
摘要
Abstract
Using the monthly precipitation data from Climate Research Unit (CRU) ,University of East Anglia in England and the global monthly mean meteorological reanalysis data at standard isobaric levels from Japan Meteorological Agency (JMA) from 1979 to 2011 ,the criterion of typical drought years in Sichuan-Chongqing region was determined with the Standardized Precipitation Index (SPI) ,and the climatological characteristics and possible causes of summer droughts in Sichuan-Chongqing region were analyzed from the aspect of atmospheric circulation .The results show that , during years with typical summer droughts ,the surface air temperature is higher and the precipitation is less than normal . The zonal circulation develops in mid-latitude regions of East Asia ,and the westerly frontal zone and the cold air mass shift northward during summer droughts .Meanwhile ,Sichuan-Chongqing region and most parts of northern China are un-der the control of mainland belt high pressure .The location of high pressure at 500 hPa field is nearly the same with the center of South Asian high pressure at 100 hPa field .Moreover ,the high pressure center at 500 hPa corresponds with the warm center in the temperature filed .This quasi -barotropic structure is the typical circulation feature of a persistent summer drought in Sichuan-Chongqing region .At the same time ,the southwesterly flow is obviously weakened from Yun-nan-Guizhou Plateau to Sichuan Basin in the low troposphere .In the anomaly wind field ,there exist northeasterly flows from Yunnan-Guizhou Plateau to Sichuan Basin ,and there is a cyclonic circulation over southern China .The entire-layer southwesterly water vapor transport in typical summer drought years is much weaker than normal in Sichuan-Chongqing re-gion .关键词
川渝地区/夏季干旱/标准化降水指数/大气环流/水汽输送Key words
Sichuan-Chongqing region/summer drought/standard precipitation index/atmospheric circulation/water vapor transport分类
农业科技引用本文复制引用
易俊莲,方建刚,刘晓东..川渝地区夏季干旱气候特征及成因分析[J].干旱地区农业研究,2013,(4):237-244,256,9.基金项目
中国科学院战略性先导科技专项B（XDB03020600）；国家自然科学基金项目（41290255）；国家重点基础研究发展规划项目 （）
