西南地区东部夏季旱涝的水汽输送特征  

The characteristics of moisture transport associated with drought/flood in summer over the east of the southwestern China

作　　者：李永华[1,2] 徐海明[1] 高阳华 李强[1] 

机构地区：[1]南京信息工程大学气象灾害省部共建教育部重点实验室,南京210044 [2]重庆市气象科学研究所,重庆401147

出　　处：《气象学报》2010年第6期932-943,共12页Acta Meteorologica Sinica

基　　金：国家自然科学基金项目(40975058;40633018);重庆市自然科学基金计划重点项目(CSTC;2008BA0022);重庆市科技攻关项目(CSTC;2009AC0125);中国气象局省所科技发展专项(CMATG2008S09)

摘　　要：利用1959—2006年西南地东部东部20个测站逐日降水量资料和NCEP/NCAR再分析月平均资料,分析了西南地区东部夏季旱涝年的水汽输送特征。结果表明,西南地区东部水汽来源主要有两个:第1条主要来自青藏高原转向孟加拉湾经缅甸和云南进入西南地区东部,第2条水汽经由孟加拉湾南部,强大的水汽输送带继续向东输送至中南半岛及南海,与南海越水道气流所携带的水汽汇合后转向至西南地区东部,而由西太平洋副热带高压西侧转向的偏南水汽对向西南地区东部水汽输送也有影响。与西南地区东部夏季降水相联系的水汽通道中,印度洋水汽通道强度最强,太平洋水汽通道强度最弱。在印度季风区,偏北的高原南侧水汽通道(经向)强度远小于偏南的印度洋水汽通道。东亚季风区夏季水汽输送经向输送大于纬向输送,而印度季风区夏季水汽输送则是纬向输送大于经向输送。西南地区东部夏季降水与纬向通道的强度变化关系密切,而与经向通道的水汽输送强度变化关系不明显。当印度季风区南支水汽输送偏弱时,印度季风区北支(高原南侧)和东亚季风区向西的水汽输送偏强,使得以纬向输送为主的印度季风区经向水汽输送加大,而以经向输送为主的东亚季风区纬向水汽输送加大,从而使东亚地区的水汽输送带偏西,西南地区东部夏季降水偏多,可能出现洪涝,反之则可能出现干旱。西南地区东部夏季水汽有弱的净流出,是一个弱的水汽源区,南边界流入水汽量最多,于旱年整个区域水汽流出较常年明显,而洪涝年则有弱的净流入。夏季水汽通道水汽输送强弱变化与同期500hPa高度场和SST场的分布形势密切相关。Based on the NCEP/ NCAR reanalysis monthly data and daily precipitation data for the 20 stations in the east of the southwestern China from 1959 to 2006.the characteristics of moisture transport associated with drought/flood in summer over the east of the southwestern China have been analyzed.The results show that there are two main water vapor paths directed to the area of the east of the southwestern China.One comes initially front the Tibetan Plateau and then turns toward the Bay of Bengal and reaches the east of the southwestern China through、Burma and Yunnan province.The other comes from the south of the Bay of Bengal with the strong vapor transport band directed to the Indo-China Peninsula and the South China Sea merging with crossing equator vapor therein.The moisture turning north from south of Western Pacific Subtropical High（WPSH） contributes also to the east of the southwestern China. The intensity of the Indian Ocean Vapor Path（IOVP） is the strongest,and the one of the Pacific Ocean Path is the weakest associated with vapor transport in the east of the southwestern China.The intensity of the Tibetan Plateau Southern Side Path is far less than that of the IOVP in the Indian Ocean monsoon area.Over the Eastern Asian monsoon area the meridional moisture transport is stronger than the zonal one,whereas the zonal vapor transport is stronger than the meridional one over the Indian Ocean area.The summer rainfall in the east of the southwestern China is connected closely with changes in the zonal moisture transport,but there is no obvious relationship between this rainfall and changes in the meridional one.The precipitation over the east of the southwestern China is more prone to flood in case the water vapor transport of the southern IOVP is weak when the strong moisture transport of by the northern Indian and the eastern Asian monsoon result in the transport direction becoming more longitudinal over the Indian monsoon zone while becoming more latitudinal over the eastern Asian area,which causes th

关 键 词：西南地区东部 夏季旱涝 水汽输送 水汽通道 

分 类 号：P461[天文地球—大气科学及气象学]