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

海平面等变化的海流监测研究。

基本信息

批准号：
11205202
负责人：
KAWABE Masaki
金额：
$ 11.14万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11205202/
关键词：
Kuroshio Monitoring Sea level data Ferry in the Tokara Strait Variations of current path Current velocity, transport

项目摘要

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.

1.我们在互联网上制作了黑潮实时监测系统，其中包括海平面等海洋学数据的时间序列。显示在黑潮的电流路径，速度和体积运输方面。我们可以看到高分辨率的黑潮时间变化，还可以访问日本气象厅NEAR-GOOS数据库中的月温度图和日本水文和海洋局发布的半月黑潮状态速报。在九州以南生成并向东传播的黑潮小弯曲是黑潮的一个主要特征，对黑潮大弯曲的形成起着重要作用。我们澄清了小弯曲可以监测的第三模式的频域经验正交函数的九州和房总半岛之间的沿海海平面。这一监测已纳入黑潮监测系统。我们继续每隔两天使用配备在“Akebono”号渡轮上的船载声学多普勒流速剖面仪（ADCP）测量九州以南的黑潮流速，并检查流速剖面。我们考虑了如何估计潮流在托卡拉海峡，以消除他们的渡轮电流数据。本文首先分析了以往的海流计资料，得出了M_2潮占优势的结论。利用系泊ADCPs对托卡拉海峡两个点的全水深流速进行了测量，结果表明，潮流以正压模态为主，斜压第三模态次之，占正压振幅的30%。如果用验潮站资料估计正压模态，并用黑潮轴的位置表示斜压模态的相对振幅和相位，就有可能估计任意时空的潮流。