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.

日本南部黑潮生物模态路径动力学及其直线路径与大曲流路径转换过程的研究。

基本信息

批准号：
05640475
负责人：
SEKINE Yoshihiko
金额：
$ 1.02万
依托单位：
Mie University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

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

在本研究过程中，我们研究了黑潮的双峰路径动力学及其转变过程。在第一年中，假设了日本南部真实沿海地形的平底模型，并研究了沿海地形效应。指出从直线路径到大曲流路径的转变是由于室户岬和纪伊半岛线下的正涡供给造成的，从大曲流路径到直线路径的转变是由于没有正涡流供给造成的。第二年，日本南部的底部地形被进一步纳入数值模型，并研究了大曲流路径通常与室户岬分离的影响。模型中只排除纪伊半岛的沿海地形，在室户岬进行平均流量的分离，但如果沿海地形影响，分离点会移至室户岬以东。如果排除室户岬和纪伊半岛的沿海地形，则分离点进一步向下游移动，这表明室户岬的地形效应对黑潮的双峰路径动力学有重要影响。由于底部坡度的稳定作用，只有在进出流量较大，涡流粘度较小的情况下，才会形成较大的曲流路径。描述这些结果的两篇论文已被 La mer 接受，目前正在印刷中，这些结果为未来的黑潮研究提供了重要的观点。关于观测数据孪生的研究仍然缺乏。然后，我对黑潮进行了三个断面观测，现在我将利用历史观测数据来讨论室户岬的地形影响。