Study on Ocean Current Minitoring with Variations of Sea Level etc.

1.在互联网上建立了黑潮实时监测系统，其中包括海平面等海洋数据的时间序列。以黑潮的水流路径、流速和流量输送表示。我们可以高分辨率地看到黑潮的时间变化，还可以在日本气象厅的NEAR-GOOS数据库中获取月温度地图，以及在日本水文海洋部门发布的《海洋状况快报》中获取黑潮状态的半月图。产生于九州南部并向东传播的黑潮小弯曲是黑潮的一大特征，对黑潮大弯曲的形成起着重要作用。我们阐明，对于九州和博索半岛之间的沿海海平面，可以用频域经验正交函数的第三模式来监测小曲折。这一监测纳入了黑潮监测系统。我们继续每两天测量一次九州以南的黑潮流速，使用配备在Akebono号渡轮上的船载声学多普勒海流剖面仪(ADCP)，并检查流速剖面。我们考虑了如何估计托卡拉海峡的潮流，以便从渡流数据中剔除它们。我们首先分析了过去的海流计资料，得出了M_2潮的优势。在此基础上，利用系泊ADCP测量了托卡拉海峡两点的全深流速，结果表明，潮流以正压模式为主，斜压第三模式次之，正压振幅约占正压振幅的30%。如果根据验潮资料估计正压模式，并且斜压模式的相对幅度和相位用黑潮轴线的位置表示，就有可能估计出任何时空的潮流。

1. We made real-time Kuroshio monitoring system on the Internet, in which time series of oceanographic data such as sea levels are. shown in terms of current path, velocity, and volume transport of the Kuroshio. We can see time variations of the Kuroshio in high resolution, and can also access to maps of monthly temperature in the NEAR-GOOS database of the Japan Meteorological Agency and semimonthly Kuroshio state in the Quick Bulletins of Oceanographic Conditions issued by the Japan Hydrographic and Oceanographic Department.2. Small meander of the Kuroshio generated south of Kyushu and propagating eastward is a major feature of the Kuroshio, and plays a great role in formation of the Kuroshio large meander. We clarified that the small meander can be monitored by the third mode of the Frequency Domain Empirical Orthogonal Functions for the coastal sea levels between Kyushu and the Boso Peninsula. This monitoring is included into the Kuroshio monitoring system.3. We continued to measure the Kuroshio velocity south of Kyushu every two days, using the shipboard acoustic Doppler current profiler (ADCP) equipped with the ferry 'Akebono', and examined velocity profiles.4. We considered how to estimate tidal currents in the Tokara Strait, in order to remove them from the ferry current data. We first analyzed past current-meter data and concluded a dominance of the M_2 tide. Then we measured full-depth current velocity at two points in the Tokara Strait using moored ADCPs, and clarified that the barotropic mode is most dominant in tidal currents, and the baroclinic third mode is secondly large with thirty percent of the barotropic amplitude. If the barotropic mode is estimated from tide-gauge data, and the relative amplitude and phase of baroclinic modes are expressed with position of the Kuroshio axis, tidal currents at any apace and time are possibly estimated.