Water mass transformation along the Indonesian throughflow in an OGCM
Water mass transformation along the Indonesian throughflow in an OGCM
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DOI：
10.1007/s10236-008-0155-4
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发表时间：
2008-10
期刊：
影响因子：
2.3
通讯作者：
A. Koch‐Larrouy;G. Madec;B. Blanke;R. Molcard
中科院分区：
文献类型：
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作者：
A. Koch‐Larrouy;G. Madec;B. Blanke;R. Molcard
连接太平洋印度洋的海洋路径描述使用定量拉格朗日方法应用到欧拉领域的海洋环流模式模拟的印度尼西亚海域。诊断的主要路线是在很好的协议，从观察推断。次级路径和太平洋环流也被量化。该模型再现了所观察到的盐渗透的亚热带沃茨从南太平洋，在印度尼西亚南部盆地的同盐分层，和冷新鲜舌退出到印度洋。这些特定的水团特性，接近所观察到的，得到的潮汐混合参数化时引入到模型中。轨迹连接在入口处和出口处的印尼通流（ITF）的水团，并沿沿着每个轨迹的混合进行量化。ITF和太平洋环流都发生了变化，这表明印度尼西亚的变化影响了印度和太平洋的层结。一个配方，形成印尼水团的建议。我们提出了三个主要特征的流通，重温经典图片的ITF及其相关的水团改造，同时仍然与观测结果一致。首先，同盐层是不是纯粹的北太平洋中层水和南太平洋亚热带水（SPSW）在班达海的等密度混合的结果，如以前所认为的。相反，所观察到的同盐层是由模型再现，但它是由两个等密混合与SPSW和占主导地位的垂直混合前班达海与NPSW。这种新的机制可能是真实的，因为该模型再现了所观察到的SPSW穿透。其次，该模型解释了为什么班达海温跃层水是如此新鲜的SPSW相比。到目前为止，唯一的解释是来自西线的淡水再循环。该模型没有重现这种再循环，而是显示出强烈的混合SPSW内的哈马黑拉和塞拉姆海，侵蚀的盐度最大值，使其签名不再是可察觉的。最后，这项工作突出了爪哇海淡水的关键作用。尽管其每年的净质量贡献很小，但其新鲜盐度贡献非常显著，是太平洋盐度最大值被侵蚀的主要原因。
The oceanic pathways connecting the Pacific Ocean to the Indian Ocean are described using a quantitative Lagrangian method applied to Eulerian fields from an ocean general circulation model simulation of the Indonesian seas. The main routes diagnosed are in good agreement with those inferred from observations. The secondary routes and the Pacific recirculation are also quantified. The model reproduces the observed salt penetration of subtropical waters from the South Pacific, the homohaline stratification in the southern Indonesian basins, and the cold fresh tongue which exits into the Indian Ocean. These particular water mass characteristics, close to those observed, are obtained when a tidal mixing parameterization is introduced into the model. Trajectories are obtained which link the water masses at the entrance and at the exit of the Indonesian throughflow (ITF), and the mixing along each trajectory is quantified. Both the ITF and the Pacific recirculation are transformed, suggesting that the Indonesian transformation affects both the Indian and Pacific stratification. A recipe to form Indonesian water masses is proposed. We present three major features of the circulation that revisit the classical picture of the ITF and its associated water mass transformation, while still being in agreement with observations. Firstly, the homohaline layer is not a result of pure isopycnal mixing of the North Pacific Intermediate Water and South Pacific Subtropical Water (SPSW) within the Banda Sea, as previously thought. Instead, the observed homohaline layer is reproduced by the model, but it is caused by both isopycnal mixing with the SPSW and a dominant vertical mixing before the Banda Sea with the NPSW. This new mechanism could be real since the model reproduces the SPSW penetration as observed. Secondly, the model explains why the Banda Sea thermocline water is so fresh compared to the SPSW. Until now, the only explanation was a recirculation of the freshwater from the western route. The model does not reproduce this recirculation but instead shows strong mixing of the SPSW within the Halmahera and Seram Seas, which erodes the salinity maximum so that its signature is not longer perceptible. Finally, this work highlights the key role of the Java Sea freshwater. Even though its annual net mass contribution is small, its fresh salinity contribution is highly significant and represents the main reason why the Pacific salinity maxima are eroded.