Efforts to forecast the current condition of Sagami Bay

Sea current information is used in a variety of fields, including navigation safety, marine economic activities, marine environment conservation, and marine leisure. The Japan Coast Guard’s Hydrographic and Oceanographic Department conducts observation in Sagami Bay (Japan) using ocean shortwave radar, and discloses and provides flow information on its website. The current information of Sagami Bay is for the past current based on the actual situation, and there is no information on the current conditions in the future. Future current information is helpful for marine activities. For example, ship operators can use it to plan safe and economical operations, while marine leisure people can use it to know the current time suitable for fishing. In addition, it is indispensable for the Japan Coast Guard to predict drifting in order to rescue drifters due to maritime accidents. This report describes a study for creating future flow information in Sagami Bay using data observed by ocean shortwave radar. It shows that the current condition in Sagami Bay also has tidal components, but components other than tidal currents are dominant. A method of estimating components other than the tidal current using moving averages and predicting them from past ocean shortwave radar data was studied. As a result, it was possible to forecast that components other than tidal current could be used practically.