大气科学2012，Vol.36Issue(5)：879-888,10.DOI:10.3878/j.issn.1006-9895.2012.11176
冬季和春季印度洋海温异常年际变率模态对中国东部夏季降水的可能影响过程
Possible Process for Influences of Winter and Spring Indian Ocean SST Anomalies Interannual Variability Mode on Summer Rainfall over Eastern China
摘要
Abstract
The thermal conditions of the Indian Ocean is an important factor that can affect the global climate and Asian monsoon variability. Previous studies have paid much more attention to sea surface temperature (SST) variability in the tropical Indian Ocean than the middle- and high-latitude South Indian Ocean, which limits the overall understanding about the Indian Ocean. This study presents the leading mode of the Indian Ocean sea surface temperature anomalies (SSTA) on interannual time scale and the possible process for its influences on summer rainfall over eastern China, expecting to provide a theoretic basis for climate variations research and prediction. The results indicate that the leading mode of the Indian Ocean SSTA on interannual time scale is characterized by southwest-northeast oriented dipole oscillation in the subtropical South Indian Ocean. The western pole is located in the southeast of Madagascar and the eastern pole lies in the west of Australia, varying consistently with the tropical Indian Ocean SSTA. Here, the positive (negative) Indian Ocean SSTA interannual variability mode is defined as positive (negative) SSTA in the western pole and negative (positive) SSTA in the eastern pole and the tropical Indian Ocean. The interannual variability mode, which can persist during winter and spring, is significantly negatively correlated with summer rainfall over the middle reach of the Yangtze River (MYR), but significantly positively correlated with rainfall over South China (SC). The possible mechanism can be described as follows: for positive Indian Ocean SSTA interannual variability mode events during winter and spring, the meridional atmospheric teleconnection of zonal wind anomalies in the Indian Ocean leads to westerly anomalies in the tropical Indian Ocean which depress the convective activities over the Maritime Continent in spring and summer. The depressed convective activities make the western Pacific subtropical high weaken and shift northward and eastward, conducing to increased rainfall over SC and reduced rainfall over MYR, and vice versa. Moreover, the Indian Ocean SSTA interannual variability mode can also influence summer rainfall over MYR by changing its water vapor transport stemming from the Indian Ocean and the Bay of Bengal.关键词
印度洋/海温异常年际变率模态/中国东部夏季降水/经向大气遥相关Key words
Indian Ocean, SSTA interannual variability mode, summer rainfall over eastern China, meridional atmospheric teleconnection分类
天文与地球科学引用本文复制引用
徐志清,范可..冬季和春季印度洋海温异常年际变率模态对中国东部夏季降水的可能影响过程[J].大气科学,2012,36(5):879-888,10.基金项目
全球变化研究国家重大科学研究计划2010CB950304,公益性行业(气象)科研专项GYHY200906018,中国科学院知识创新工程重要方向项目KZCX2-YW-BR-14,国家自然科学基金资助项目41175071 （气象）
