Asymmetric Impacts of ENSO on Boreal Winter Southern Subtropical Cell in the Indian Ocean
编号:317 访问权限:仅限参会人 更新:2024-10-11 20:27:17 浏览:174次 张贴报告

报告开始:2025年01月15日 19:20(Asia/Shanghai)

报告时间:15min

所在会场:[S60] Session 60-Indian Ocean Dynamics, Air-sea Interaction and Biogeochemical Cycles [S60-P] Indian Ocean Dynamics, Air-sea Interaction and Biogeochemical Cycles

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摘要
The interannual relationships between the southern subtropical cell (SSTC) in the Indian Ocean (IO) and the El Niño‐Southern Oscillation (ENSO) are examined. The results demonstrate that the impacts of ENSO on the boreal winter IO SSTC display a notable negative skewness, with the amplification of the SSTC during La Niña being far stronger than its reduction during El Niño. This difference is mainly attributed to an asymmetry in anomalous meridional geostrophic transport, characterized by more robust southward (weaker northward) geostrophic transport anomalies during La Niña (El Niño) events. Further analyses reveal that the differing longitudinal positions of the ENSO‐related sea surface temperature anomaly (SSTA) are the primary drivers of the asymmetry in anomalous meridional geostrophic transport via the oceanic and atmospheric teleconnections. Compared to the warm SSTA in El Niño events, the La Niña‐related cool SSTA in the central‐eastern equatorial Pacific displays a greater westward extension, which induces stronger surface easterlies over the western equatorial Pacific, and then initiates a more substantial sea surface height anomaly (SSHA) in the southeast Indian Ocean (SEIO) through oceanic waveguides. This leads to a heightened zonal SSHA gradient
over the southern IO, resulting in a larger anomalous meridional geostrophic transport. On the other hand, the westward extension of negative SSTA during La Niña winters triggers anomalous cyclonic northerlies along the western coast of Australia by shifting the Walker circulation westward. These coastal northerlies amplify the positive SSHA signals in the SEIO and enhance the anomalous meridional geostrophic transport, ultimately contributing to a more robust IO SSTC response.
 
关键词
Indian Ocean,Meridional overturning circulation,ENSO
报告人
Yu Liu
PhD South China Sea Institute of Oceanology, Chinese Academy of Sciences;State Key Laboratory of Tropical Oceanography

稿件作者
Yu Liu South China Sea Institute of Oceanology, Chinese Academy of Sciences;State Key Laboratory of Tropical Oceanography
Kang Xu South China Sea Institute of Oceanology, Chinese Academy of Sciences;State Key Laboratory of Tropical Oceanography
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重要日期
  • 会议日期

    01月13日

    2025

    01月17日

    2025

  • 09月27日 2024

    初稿截稿日期

  • 01月17日 2025

    注册截止日期

主办单位
State Key Laboratory of Marine Environmental Science, Xiamen University
承办单位
State Key Laboratory of Marine Environmental Science, Xiamen University
Department of Earth Sciences, National Natural Science Foundation of China
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