| 摘要: |
| 本文利用Princeton Ocean Model (POM) 数值模式模拟了日本南部黑潮的路径变异情况,分析了黑潮大弯曲事件的形成机制。结果表明,当黑潮处于非大弯曲路径时,相对位势涡度的平均值呈现递减趋势,说明日本南部低位势涡度水在不断积累,这样会使得四国再循环流的强度增强,迫使黑潮保持平直路径,同时,近岸黑潮垂直流速剪切增大,斜压不稳定性的作用也逐渐增大；当黑潮从非大弯曲路径向大弯曲路径过渡时,再循环流强度的减弱会导致黑潮的流速剪切减小。根据海表高度异常场以及海洋上层流场信息发现,近岸黑潮附近的气旋涡会随着再循环流区域反气旋涡的东侧向南运动,最终导致黑潮大弯曲的发生。通过涡流的能量分析结果显示,斜压不稳定性是黑潮大弯曲路径形成的主要原因。 |
| 关键词: 黑潮路径变异 POM模式 斜压不稳定性 |
| DOI： |
| 分类号:P731.21 |
| 基金项目:国家自然科学基金（41230420） |
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| The study of the Kuroshio path variations south of Japan in POM model |
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Zou Guang-an
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Institute of Oceanology,Chinese Academy of Sciences
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| Abstract: |
| In this study, Princeton Ocean Model (POM) was used to simulate the Kuroshio path variations south of Japan, the formation mechanism of the Kuroshio large meander events was analyzed. The results shown that a decreasing trend of the averaged relative vorticity when the Kuroshio taken the non-large path, indicated the accumulation of the low-PV(potential vorticity) south of Japan and its intensified the strength of the Shikoku recirculation gyre, which forced the Kuroshio in its straight path state, while the vertical velocity shear of the alongshore Kuroshio was increasing, and the impact of baroclinic instability was also gradually increasing. During the transition period from the Kuroshio non-large meander to the large meander, a sudden release of velocity shear corresponded well to the weakening of the Shikoku recirculation gyre. According to the sea surface height (SSH) anomaly fields and the information of mean velocity field at the upper ocean, it was found that the cyclonic eddy around offshore Kuroshio moved southward which was carried by a southward flow in the eastern part of the anticyclonic eddy in the region of Shikoku recirculation gyre, which lead to the eventually development of Kuroshio large meander. The results of eddy energetic analysis indicated that the baroclinic instability was mainly responsible for the formation of Kuroshio large meander. |
| Key words: Kuroshio path variations POM model Baroclinic instability |