印度洋海表温度主模态及其与亚洲夏季季风的关系  

LEADING MODE OF INDIAN OCEAN SST AND ITS IMPACTS ON ASIAN SUMMER MONSOON

作　　者：杨明珠[1] 丁一汇[1] 李维京[1] 毛恒青[2] 

机构地区：[1]中国气象局气候开放实验室国家气候中心,北京100081 [2]中国气象局华风影视信息集团,北京100081

出　　处：《气象学报》2007年第4期527-536,共10页Acta Meteorologica Sinica

基　　金：国家重点基础研究发展计划973计划"亚印太交汇区海气相互作用及其对我国短期气候和影响"课题四"亚洲季风区水分循环和变异机制"(2006CB403604)和课题六"资料同化及东亚气候可预报性"(2006CB403606)。

摘　　要：分析了印度洋SST主模态的时空特征,并探讨其对亚洲夏季季风的影响,结果表明:印度洋SST主模态的主要特征为整个海盆一致的增温趋势,主要具有准3 a和准11 a周期,在1976/1977年和1997/1998年分别具有两次年代际显著增温。印度洋SST主模态与中国雨区夏季降水有很好的关系,其增温趋势与华北、东北南部、华南东部和西南西部降水减少,长江中下游地区、东北北部和西北地区降水增多具有很好的关系,并与长江中下游梅雨雨量具有较好的正相关关系;其变化趋势对亚洲夏季季风系统具有显著影响,在高空,使南亚高压、高原南侧的高空东风以及从南海、东南亚至西南印度洋的高空越赤道气流减弱,但增强10°—20°N、40°—110°E的北风;在中层,使西北太平洋副热带高压强度偏强,面积偏大;在低层,增强索马里越赤道气流,但却削弱印度夏季季风低层环流,并且在加强东亚地区的低层南风在中国长江中下游地区及其以南地区的同时减弱华北地区的低层西南风;地面,使亚洲大陆的气压升高;与对流层整层垂直积分水汽输送通量的相关分布与低层环流的相似。因此,印度洋SST主模态的上升趋势是亚洲夏季季风趋于减弱和中国雨带南移的一个原因。The Indian Ocean sea surface temperature （SST） was analyzed by using empirical orthogonal function （EOF）, and the leading mode of Indian Ocean SST （LMIO） was extracted. The Major spatial and temporal characters of LIMO were discussed. Based on the above analysis, the relationships between LMIOS and China summer rainfalls （CSR） were further investigated, and the impacts of LMIOS on Asian summer monsoon circulation were explored. The following notable results are obtained： the significant evolutional characters of LMIO are the consistent warming trend of almost the whole Indian Ocean basin, the distinctive quasi-3 and quasi-10 oscillations and remarkably interdecadal warming in 1976/1977 and 1997/1998, respectively. The increasing trend of LMIO was close related with CSR, i.e. it was close related with reductions in the summer precipitation in North China, southern Northeast China, eastern South China and western Southwest China, and with increases in summer precipitation in the middle and lower reaches of Yangtze River, northern Northeast China and Northwest China. And it was rather close/positively related with Meiyu precipitation in the middle and lower reaches of Yangtze River. The LMIO rising trend had distinctive impacts on the Asian summer monsoon system and the water vapor transports. That is to say, the consistent rising trend of LMIO was associated with the weakening of South Asian high, the easterly south of the Tibetan plateau, and the cross-equatorial flows over the South China sea-Southeast Asia-southwest Indian ocean area, and the strengthening of northerly winds over 10°N-20°N, 40°E-110°E at the upper level; with the strengthening of northwest Pacific ocean subtropical high and its larger area at the middle level; and with the strengthening of Somali cross-equatorial jet and the weakening of the low circulation of Indian summer monsoon in the sector of India and Indian ocean, and the strengthening of lower level south wind over the middle and lower reaches of Yangtze River and

关 键 词：印度洋SST主模态 中国夏季降水 亚洲夏季季风 水汽输送 

分 类 号：P732[天文地球—海洋科学]