A Study on the Biomodal Path Dynamics of the Kuroshio South of Japan and Their Transformation Process between the Straight Path and the Large Meander Path.

本文对黑潮的双峰路径动力学及其转化过程进行了研究。第一年，假设了日本南部真实海岸地形的平底模型，并对海岸地形效应进行了检验。指出由直线路径向大曲径路径的转变是由于Muroto角和Kii半岛的正涡量供应。相反，从大曲流路径到直流路径的转变是由于海岸地形分离的流路径没有提供正涡量造成的。在这第二年，日本南部的海底地形进一步被纳入数值模型，并检查了它们的影响。从图中可以看出，这条蜿蜒的大小路通常与Muroto角分开。如果只排除Kii半岛的海岸地形，则在Muroto角进行平均流量的分离。但是，如果排除Muroto角的沿海地形，则sepa…More ration point转移到Muroto角以东。如果排除Muroto角和Kii半岛的海岸地形，分离点将进一步向下游移动。结果表明，室户角的地形效应对黑潮的双峰路径动力学有重要影响。由于底坡的稳定化作用，只有在进出流大于80 Sv、涡流粘度较小的情况下才会形成较大的曲流路径。认为在强非线性系统条件下，通过斜压失稳形成大曲径。描述这些结果的两篇论文被La mer接受，现在正在印刷中。这些结果对今后黑潮的研究具有重要意义。但是，对观测资料分析的相关研究还比较缺乏。然后，我在黑潮进行了三次局部观察，现在我正在检查观察的结果。本文将利用历史观测资料，讨论Muroto角的地形效应。少

The bimodal path dynamics of the Kuroshio and their transformation process have been examined in the course of this study. In the first year, a flat bottom model with realistic coastal topographies south of Japan was assumed and the coastal topographic effect was examined. It has been pointed out that the transformation from straight path to large meander path is due to the positive vorticity supply from the Cape Muroto and Kii Penisula. Conversely, the transformation from the large meander path to the straight path is caused by no supply of the positive vorticity by the separated current path from the coastal topographies. In this second year, bottom topographies south of Japan is further included in the numerical model and their effects are examined. It is shown that the large meander path commonly separates from the Cape Muroto. If only the coastal topography of Kii Peninsula is excluded from the model, separation of the mean flow is carried out at the Cape Muroto. However, the sepa … More ration point shifts to east of the Cape Muroto, if the coastal topography of the Cape Muroto is excluded. If the coastal topographies of the Cape Muroto and Kii Peninsula are excluded, the separation point shifts further downstream. It is demonstrated that topographic effect of the Cape Muroto has an important influence on the bimodal path dynamics of the Kuroshio. Because of the stabilization effect of the bottom slope, large meander path is formed only in the case with large in- and outflow of 80 Sv and small eddy viscosity. It is suggested that the large meander path is formed through the baroclinic instability under the condition of strong nonlinear system. The two papers describing these results were accepted to La mer and they are now in printing. These results give important views for a future study on the Kuroshio. However, corresponding study on the observational data analyzes are still lacking. Then, I performed three sectional observations across the Kuroshio and I am now examining results of the observation. The topographic effect of Cape Muroto will be dicussed by use of the historical observational data. Less