盛夏四川盆地西部地区降水年际变化及其对应的环流异常  

Interannual Variation in the Mid-Summer Rainfall over the Western Sichuan Basin and the Associated Circulation Anomalies

作　　者：胡德强[1] 陆日宇[2] 苏秦[2,3] 范广洲[1] 

机构地区：[1]成都信息工程学院大气科学学院,成都610225 [2]中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室(LASG),北京100029 [3]中国科学院大学,北京100049

出　　处：《大气科学》2014年第1期13-20,共8页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金-云南联合基金重点项目U0933603;国家自然科学基金项目41275079;国家公益性行业(气象)科研专项GYHY201006023;四川省青年基金项目2012JQ0062

摘　　要：利用7、8月全国756站站点降水资料、NCEP/NCAR再分析资料的月平均资料,研究了盛夏四川盆地西部地区降水年际变化的基本特征及其对应的环流异常,并分析了该地区与江南地区降水年际变化的关系及其对应的700 hPa环流异常。结果表明:四川盆地西部地区盛夏降水偏多年,四川盆地上空为显著的南风异常,说明西南涡较常年活跃,同时西太平洋副热带高压偏北;而降水偏少时,上述环流异常符号相反,但更加明显,说明西南涡明显弱于常年,西太平洋副热带高压偏南。此外,四川盆地西部盛夏降水年际变化和我国西北、华北地区降水呈明显的正相关关系,而与江南地区降水有明显的负相关关系。这些关系与对流层低层环流异常有关。Interannual variation of the mid-summer （July and August） rainfall over the western Sichuan Basin and associated lower-tropospheric circulation anomalies are analyzed by using the rainfall data at 730 stations provided by the Chinese Meteorological Data Center, and the National Centers for Environmental Prediction/National Center for Atmospheric Research （NCEP/NCAR） reanalysis data. The lower-tropospheric circulation anomalies associated with greater and lesser amounts of rainfall over the western Sichuan Basin are examined. More rainfall over the western Sichuan Basin corresponds to a significant southerly anomaly over the basin, suggesting a stronger occurrence of the Southwest Vortex and a northward displaced subtropical high over the western Pacific. Less rainfall over this basin corresponds to more significant circulation anomalies but with opposite signs, suggesting a weaker Southwest Vortex and asouthward shift of the subtropical high. Moreover, interannual variation in mid-summer rainfall in the western Sichuan Basin has a positive and significant correlation with that in Northwest China and North China and a negative and significant correlation with that in South China. These correlations can be explained by the lower tropospheric circulation anomalies.

关 键 词：四川盆地西部 降水异常 江南地区 盛夏 年际变化 环流异常 

分 类 号：P426[天文地球—大气科学及气象学]