Basin-wide Warming in the Equatorial Indian Ocean Associated with El Nino
Basin-wide Warming in the Equatorial Indian Ocean Associated with El Nino
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DOI：
10.2151/sola.2005-024
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发表时间：
2005
期刊：
影响因子：
1.9
通讯作者：
M. Ohba;H. Ueda
中科院分区：
文献类型：
--
作者：
M. Ohba;H. Ueda
考虑到季风环流和与主要厄尔尼诺相关的调制Walker环流之间的季节耦合过程不同，研究了赤道印度洋(IO)盆地范围变暖的物理过程。在对6个暖事件的综合分析中，沿赤道的逆Walker环流出现在通过太平洋的热带IO上，导致厄尔尼诺成熟阶段之前赤道IO上的地面东风异常。从北半球秋季到冬季，辐散的东风异常阻碍了赤道西风的发展。利用一个减重海洋模式，结果表明，赤道IO上的调制海面流有可能通过海洋表面的热交换对整个盆地变暖做出贡献。这些结果表明，季风所涉及的强季节性对于理解海温年际异常的季节锁相特征具有重要意义。
A physical process of basin-wide warming in the equatorial Indian Ocean (IO) is examined in view of the seasonally different coupling processes between the monsoon circulation and the modulated Walker circulation associated with major El Nino. In the composite analysis of six warm episodes, the reversed Walker circulation along the equator appears over the tropical IO through the Pacific Ocean, resulting in anomalous surface easterlies over the equatorial IO prior to the mature phase of the El Nino. From boreal fall to winter, the divergent easterly wind anomalies prevent the development of the climatological equatorial westerly. Using a reduced gravity ocean model, it is shown that the modulated surface flow over the equatorial IO has a potential to contribute to the basin-wide warming through the heat exchange of the ocean surface. These results imply that the strong seasonality involved in monsoon is important to understand the seasonal phase-locked feature of interannual SST anomalies.