热带海洋学报

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沿岸风和海洋波动在北向索马里流生成中的作用

储小青1, 2彭启华3   

  1. 1. 热带海洋环境国家重点实验室(中国科学院南海海洋研究所), 广东 广州 510301;

    2. 南方海洋科学与工程广东省实验室(广州), 广东 广州 510301;

    3. 斯克利普斯海洋研究所(美国加州大学圣地亚哥分校),美国加利福尼亚州 拉荷亚92093

  • 收稿日期:2022-03-23 修回日期:2022-05-19 出版日期:2022-06-07 发布日期:2022-06-07
  • 通讯作者: 储小青
  • 基金资助:

    国家自然科学基金项目(42076021; 42005035); 广东省科技计划项目(2021A1515011534)

The roles of alongshore wind and ocean wave in the northward Somali Current generation

CHU Xiaoqing1, 2, 3, PENG Qihua3

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  1. 1. State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;

    2. Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China

    3. Scripps Institution of Oceanography (University of California, San Diego), California La Jolla 92093

  • Received:2022-03-23 Revised:2022-05-19 Online:2022-06-07 Published:2022-06-07
  • Contact: Xiao-Qing CHU
  • Supported by:

    National Natural Science Foundation of China (42076021; 42005035); Science and Technology Planning Project of Guangdong Province, China (2021A1515011534)

摘要: 基于同化资料和数值模式,本文研究了北向索马里流(NSC)的季节特征和产生机制。NSC在5月开始出现,在8-9月向北延伸至近15°N,并形成一个强盛的反气旋式环流。10月下旬,NSC开始减弱,并于11月消失。NSC由局地沿岸风和东侧西传的海洋波动共同激发。在5-7月,在局地西南沿岸风的协助下,东非沿岸流(EACC)跨越赤道进入北印度洋,形成了NSC。在8-10月,即便无局地西南沿岸风,来自阿拉伯海东边界的海洋波动和EACC一起依旧能形成NSC。研究表明,局地沿岸风虽能诱发近岸的环流结构,但NSC关联的影响范围较大的反气旋式环流结构则由西传的海洋波动所激发。本研究揭示了NSC的产生机制,为海洋波动调控环流提供了实质性证据。

关键词: 北向索马里流, 海洋波动, 局地风场, 季节变化, 热带印度洋

Abstract: By analyzing reanalysis data and conducting ocean modes experiments, this study investigates seasonal variation and dynamics of the norward Somali Current (NSC) in the tropical Indian Ocean. The results show that the NSC appears starting from May, gradually strengthens and extends norward to 15N during August-September, and forms a strong anti-cyclonic circulation—the Great Whirl. The NSC weakens significantly in late October, and disappears in November. The NSC results from local alongshore wind forcing and westward propagational Rossby waves. During May-July, alongshore wind forcing induces the East African Coast Current (EACC) to cross the equator to form the NSC. During August-October, even without alongshore wind forcing, the Rossby waves together with EACC can still forms the NSC. Further analysis suggests that, although alongshore wind forcing incudes near-shore current, the Great Whirl is caused primarily by the Rossby waves. This research reveals dynamics of the NSC, and provides substantial evidences for ocean waves modulating ocean currents.

Key words: northward Somali Current, ocean waves, local wind forcing, seasonal variation, the tropical Indian Ocean