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热带海洋学报

• • 上一篇    

东南印度洋低盐水舌低频变化机制分析

庞嫣然1, 2, 孙启伟3, 4, 张玉红1, 2, 5, 张莹1, 2, 5, 池建伟1, 2, 5, 杜岩1, 2, 5   

  1. 1. 热带海洋环境与岛礁生态全国重点实验室(中国科学院南海海洋研究所), 广东 广州 510301;

    2. 中国科学院大学, 北京 100049;

    3. 南方海洋科学与工程广东省实验室(广州), 广东 广州 511458;

    4. 海洋科学系与南方海洋科学与工程广东省实验室(广州)香港分部(香港科技大学), 香港 999077;

    5. 海洋遥感广东省重点实验室(中国科学院南海海洋研究所), 广东 广州 510301



  • 收稿日期:2025-11-17 修回日期:2025-12-17 接受日期:2025-12-29
  • 通讯作者: 杜岩
  • 基金资助:

    国家自然科学基金项目(42090042、42306026); 中国科学院项目(183311KYSB20200015); 中国科学院南海海洋研究所项目(LTO2306、SCSIO202201、SCSIO2023HC07); 广东省重大人才工程项目(2024TQ08A880)

Analysis of the mechanisms underlying the low-frequency variability of the low-salinity tongue in the Southeastern Indian Ocean

PANG Yanran1, 2, SUN Qiwei3, 4, ZHANG Yuhong1, 2, 5, ZHANG Ying1, 2, 5, CHI Jianwei1, 2, 5, DU Yan1, 2, 5   

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

    2.  University of Chinese Academy of Sciences, Beijing 100049, China;

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

    4.  Department of Ocean Science and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Hong Kong University of Science and Technology, Hong Kong 999077, China;

    5.  Guangdong Key Laboratory of Ocean Remote Sensing, South China Sea Institute of Oceanology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China



  • Received:2025-11-17 Revised:2025-12-17 Accepted:2025-12-29
  • Supported by:

    National Natural Science Foundation of China (42090042, 42306026); Chinese Academy of Sciences (183311KYSB20200015); South China Sea Institute of Oceanology (LTO2306, SCSIO202201, SCSIO2023HC07); Key Talents Project of Guangdong Province (2024TQ08A880)

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摘要： 海洋盐度是全球水循环的指示因子, 对海洋环流、海平面高度和海洋层结都有重要调控作用，在海洋热力学以及动力学过程中也起着关键作用。近年来, 热带印度洋海域的盐度变化和气候响应受到广泛关注。本研究采用近31年的卫星遥感、海洋观测和模式再分析资料, 研究了热带南印度洋低盐水舌的低频变化及形成机制。结果表明, 低盐水舌的体积和平均盐度均存在以准12年为周期的年代际变化, 该变化主要与太平洋年代际涛动(Interdecadal Pacific Oscillation, IPO)有密切联系。进一步分析表明, 在年代际尺度上, 上层50m低盐水舌的体积变化主要由局地降水影响。热带太平洋海温异常激发大气环流异常, 导致热带东南印度洋持续降水异常, 进而改变表层低盐水舌的范围, 主导上层50m低盐水舌体积变化。然而, 在次表层50—200m, 低盐水舌的体积和平均盐度变化主要受印尼贯穿流(Indonesian Throughflow, ITF)淡水输送的影响。在IPO负相位期间, 热带太平洋风场异常激发海洋波动调整, 加强了ITF跨海盆盐度输送, 造成东南印度洋次表层低盐水舌体积扩张和平均盐度降低。本文从低盐水舌的三维变化特征出发, 揭示了不同深度低盐水舌体积、平均盐度与局地淡水强迫、印尼贯穿流盐输送的关系, 有助于加深对区域特征水团响应长期气候变化的理解。

关键词: 印尼贯穿流, 东南印度洋, 海洋盐度, 年代际变率

Abstract: Ocean salinity serves as a key indicator of the global water cycle and exerts important controls on oceanic circulation, sea level, and stratification, thereby playing a critical role in marine thermodynamic and dynamic processes. In recent years, salinity variability in the tropical Indian Ocean, particularly its dynamic mechanisms and climatic effects, has attracted growing scientific interest. Using 31 years of satellite observations, in-situ data sets, and model reanalysis data, this study investigates the decadal variability and formation mechanisms of the low salinity tongue in the South Indian Ocean between the equator and 20ºS. The results indicate that both the volume and mean salinity of the low-salinity tongue exhibit a quasi-12-year oscillation, which is primarily associated with the Interdecadal Pacific Oscillation (IPO). Further analysis reveals that on decadal timescales, variability in the volume of the upper 50m low-salinity tongue is mainly driven by local precipitation. Through anomalous atmospheric circulation, sea surface temperature anomalies in the tropical Pacific lead to multi-year precipitation anomalies in the southeastern Indian Ocean, which subsequently alter the west extension of the surface low-salinity tongue and ultimately govern its volume variability in the upper 50 m. However, in the subsurface layer (50—200 m), variability in the volume and average salinity of the low salinity tongue is dominated by freshwater transport associated with the Indonesian Throughflow (ITF). During negative IPO phases, wind anomalies over the tropical Pacific trigger oceanic wave adjustments, which enhance the ITF salinity transport. This process subsequently leads to an expansion of the low salinity tongue and a decrease in its average salinity in the southeastern Indian Ocean. Based on the three-dimensional variability of the low salinity tongue, this study reveals the relationships between the volume and average salinity of the low salinity tongue at different depths and local freshwater forcing, as well as salinity transport by the ITF, thereby contributing to an improved understanding of how regional water mass changes respond to long-term climate changes.

Key words: Indonesian Throughflow, Southeastern Indian Ocean, Ocean Salinity, Decadal Variability