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

1. 我们在互联网上制作了实时黑潮监测系统，在该系统中，海平面等海洋数据的时间序列是实时的。用黑潮的当前路径、速度和体积传输来表示。我们可以高分辨率地看到黑潮的时间变化，也可以在日本气象厅的NEAR-GOOS数据库中获取月温图，在日本水文海洋部发布的《海洋状况快讯》中获取半月黑潮状态图。黑潮的小曲流发源于九州以南并向东延伸，是黑潮的一大特征，对黑潮大曲流的形成起着重要作用。通过九州-渤索半岛沿海海平面频域经验正交函数的第三模态分析，阐明了小曲流可以监测。这种监测包括在黑潮监测系统中。我们继续每两天测量九州南部的黑潮速度，使用渡轮“Akebono”配备的船载声学多普勒电流分析器（ADCP），并检查速度剖面。我们考虑了如何估计托卡拉海峡的潮流，以便从渡轮流数据中去除它们。我们首先分析了过去的海流测量资料，得出了M_2潮占优势的结论。利用系泊式ADCPs测量了托卡拉海峡两个点的全深流速，明确了正压型在潮流中占主导地位，斜压第三型次之，占正压振幅的30%。如果用测潮资料估计正压模态，用黑潮轴的位置表示斜压模态的相对幅值和相位，就有可能估计任何时间和任何地点的潮流。

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.