Field research on hydraulic problems concerning coasts and harbors facing oceans and development of data sharing system

在研究期间，我们使用两台波速仪对阿卡巴内港附近的太平洋海岸进行了三次波浪观测，观测时间分别为96年9月7日、96年10月19日、96年9月10日、97年10月30日和98年9月5日至10月1日。我们获得了从港口附近经过的几个台风提供的高海浪记录。我们还在部分台风靠近港口时对港口进行了海浪和海流的测量，根据海浪资料研究了港口的离岸波浪和振荡特征，其中重点研究了长周期波的放大和传播特性。我们还建立了有限元模型来模拟港口的强迫振动，并将数值结果与实测值进行了比较，研究了港口的强迫振动特性。主要研究结果如下：(1)长周期波的大小随波高的增大而增大。长周期波的振幅几乎与有效波高和波周期的乘积成正比。(2)近海海域的长周期波由近岸分量和近岸分量组成，两种分量的震级相近。通过分析两个测点之间的波记录的互相关性，我们可以区分每个分量波中的入射波和反射波。(3)阿卡巴内港存在100s、300s和800s的多频响应。采用线性长波响应的数值模拟方法与实际观测结果不太吻合，开发了WWW服务器来提供海浪数据共享服务，所有海浪数据都在互联网上向公众开放。除波浪资料外，还包括风、大气气压分布和台风轨迹等资料。据统计，对该数据库的访问次数约为数百次。

During the research period, we carried out wave observations three times for the periods of Sep.7, '96 - Oct.19, '96, Sept.10, '97 - Oct.30'97 and Sept.5'98 - Oct.1'98 on the Pacific coast off Akabane harbor using two wave and current meters. We obtained high wave records provided by several typoons passing near the harbor. We also carred out wave and current measurements in the harbor when some of the typhoon became close to the harbor.On the basis of the wave data, we investigated the characteristics of offshore waves and oscillation in the harbor, where we especially focused on long period waves and studied its amplification and propagation properties. We also developed FEM model to simulate forced oscillation in the harbor, by which we studied oscillation characteristics comparing numerical and observed results. The main results are as follows : (1) The magnitudes of long period waves increase as wave heights increase. The amplitude of long period waves is almost proportional to the product of significant wave height and wave period. (2) Long period waves in offshore zone are comprised of on-offshore components and longshore components at similar degree of magnitudes. By analyzing cross correlations of wave records between two measuring points, we can distinguish incident and reflected waves in each component waves. (3) In Akabane harbor, there exist multiple frequency responses with 100S, 300s and 800s. The numerical simulation, where linear response to linear long waves is assumed, does not give sufficient agreemet with observations.We developed WWW server to give the service of wave data sharing, where all the wave data are open to public on the internet. In addition to wave data, the data of wind, atomospheric pressure distribution and typhoon trajectories are also involved. About several hundreds times of access to the database have been counted.