Recently, a large-scale earthquake is predicted to occur in Japanese coast. There is a possibility that the tsunami is generated along with the earthquake occurrence. For that purpose, it is important to grasp the information on the generation of tsunami instantaneously. Additionally, whether this information can be effectively transmitted becomes an acute problem. Therefore, it is necessary for understanding the attainment of the tsunami by the distant point and earlier. Above all, the high frequency radar is expected as a technique to which the tsunami can promptly be observed by the distant point. In the observation with high frequency radar, there is a possibility from the coast at about 80km can be known the tsunami. Moreover, it is very useful because time necessary for the observation is about one minute.
In this study, the accuracy of obtained data with high frequency radar was investigated based on the current velocity at Fort No. 2 in Tokyo Bay and it was examined to exclude the wind current effect in observed data.