Variability of boreal spring Hadley circulation over the Asian monsoon domain and its relationship with tropical SST
Variability of boreal spring Hadley circulation over the Asian monsoon domain and its relationship with tropical SST
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DOI：
10.1007/s00382-019-05079-3
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发表时间：
2019-12
期刊：
影响因子：
4.6
通讯作者：
Yaqi Wang;Juan Feng;Jianping Li;Ran An;Lanning Wang
中科院分区：
文献类型：
--
作者：
Yaqi Wang;Juan Feng;Jianping Li;Ran An;Lanning Wang
研究了近40年来亚洲季风区春季Hadley环流的变化。区域HC的气候分布是赤道对称的，在每个半球都有围绕赤道的上升分支和围绕副热带的下沉分支。第一主模态（EOF 1）为赤道非对称型，其主体位于南半球，上升分支位于赤道以北。该模态主要以年际变化为特征，并与厄尔尼诺-南方涛动（ENSO）有关。随着拉尼娜事件的发展，沿着热带印度洋（TIO）出现了显著的负海温异常，但南印度洋海温异常的幅度大于北方海温异常的幅度，从而促进了EOF 1的形成。第二主振型（EOF 2）的空间分布是主体位于北方半球（NH），上升分支位于赤道以南。这种模式的时间变化与TIO的变暖有关。TIO南部海温的增暖速度快于北方海温，导致上升分支向南迁移。上述结果表明，SST纬向分布对区域HC的变率起着关键作用。
The variability of boreal spring Hadley circulation (HC) over the Asian monsoon domain over the last four decades is explored. The climatological distribution of the regional HC is symmetric of the equator, with the ascending branch around the equator and sinking branch around the subtropics in each hemisphere. The first dominant mode (EOF1) of the regional HC is equatorial asymmetric, with the main body in the Southern Hemisphere (SH) and the ascending branch to the north of the equator. This mode is mainly characterized by interannual variation and is related to El Niño-Southern Oscillation (ENSO). Significant negative sea surface temperature (SST) anomalies are observed over the tropical Indian Ocean (TIO) along with the development of La Niña events; however, the magnitude of SST anomalies in the southern Indian Ocean is greater than that in the northern counterpart, contributing to EOF1 formation. The spatial distribution of the second dominant mode (EOF2) is with the main body lying in the Northern Hemisphere (NH) and the ascending branch located to the south of the equator. The temporal variation of this mode is connected to the warming of the TIO. The warming rate of the southern TIO SST is faster than that in the northern counterpart, resulting in the southward migration of the rising branch. The above result indicates the critical role of the meridional distribution of SST on the variability of the regional HC.