Modelling the influence of North Atlantic multidecadal warmth on the Indian summer rainfall
Modelling the influence of North Atlantic multidecadal warmth on the Indian summer rainfall
复制标题
DOI：
10.1029/2007gl032901
复制
发表时间：
2008-03
影响因子：
5.2
通讯作者：
Shuanglin Li;J. Perlwitz;X. Quan;M. Hoerling
中科院分区：
文献类型：
--
作者：
Shuanglin Li;J. Perlwitz;X. Quan;M. Hoerling
用大气环流模式进行的集合试验表明，大西洋数十年振荡(AMO)的正(暖)海洋位相增加了印度夏季降水。这种加强是由北大西洋温带温暖推动的，一些抵消与热带北大西洋温暖反应的季风减弱有关。从机制上讲，温暖的温带北大西洋海温增加了当地的降水，引发了温带外弧形的波列响应。后者导致季风平均经向气流的北部下沉加剧，以及北非、中东和西印度洋普遍存在的低地面气压，导致印度季风槽加强和季风降水增加。温暖的热带北大西洋海温主要增加热带大西洋局地降水，导致热带受限的响应，包括印度洋上的低层东风异常和印度上空动力引起的下沉干燥。
Ensemble experiments with an atmospheric general circulation model reveal that a positive (warm) ocean phase of the Atlantic Multidecadal Oscillation (AMO) increases Indian summer rainfall. The intensification is driven by extratropical North Atlantic warmth, with some cancellation associated with monsoon weakening in response to tropical North Atlantic warmth. Mechanistically, warm extratropical North Atlantic SSTs increase local rainfall, inducing an arching extratropical wavetrain response. The latter leads to intensified northern subsidence of monsoon mean meridional streamflow as well as widespread low surface pressure over North Africa, the Middle East and the western Indian Ocean contributing to a strengthened Indian monsoon trough and increased monsoon rainfall. Warm tropical North Atlantic SSTs primarily increase local tropical Atlantic rainfall that induces a tropically‐confined response consisting of low level easterly wind anomalies over the Indian Ocean and dynamically induced subsident drying over India.