Effects of Koshu Seamount on the Development of Baroclinic Instability Leading to the Kuroshio Large Meander
Effects of Koshu Seamount on the Development of Baroclinic Instability Leading to the Kuroshio Large Meander
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DOI：
10.1175/jpo-d-17-0050.1
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发表时间：
2017-03
期刊：
影响因子：
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通讯作者：
Yuki Tanaka;T. Hibiya
中科院分区：
文献类型：
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作者：
Yuki Tanaka;T. Hibiya
摘要日本南部黑潮呈现出大曲流（LM）路径与非大曲流（NLM）路径的双峰起伏。从南纬向南纬的转变是由日本西南部产生的一个小曲流触发的。小曲流首先沿着黑潮向东（下游）传播，然后迅速扩大到位于日本以南约200公里的Koshu海山，形成黑潮的LM路径。虽然古州海山对小曲流的快速扩大是必不可少的，但其潜在的物理机制尚不完全清楚。在这项研究中，使用考虑底部地形影响的两层准地转模型重新审视了Koshu海山的作用。数值实验结果表明，只有结合模拟古州海山的海底地形，才能成功地再现从低海拔路径到低海拔路径的过渡。在这种情况下，上层蜿蜒槽被迅速放大…
AbstractThe Kuroshio south of Japan shows bimodal path fluctuations between the large meander (LM) path and the nonlarge meander (NLM) path. The transition from the NLM path to the LM path is triggered by a small meander generated off southwestern Japan. The small meander first propagates eastward (downstream) along the Kuroshio and then rapidly amplifies over Koshu Seamount, located about 200 km south of Japan, leading to the formation of the LM path of the Kuroshio. Although Koshu Seamount is essential for the rapid amplification of the small meander, the underlying physical mechanism is not fully understood. In this study, the role of Koshu Seamount is revisited using a two-layer quasi-geostrophic model that takes into account the effects of bottom topography. Numerical experiments show that the transition from the NLM path to the LM path can be successfully reproduced only when bottom topography mimicking Koshu Seamount is incorporated. In this case, the upper-layer meander trough is rapidly amplified...