Being situated in Northwest Kyushu, Sasebo Bay is connected with the open sea (East China Sea) and also connected with typical enclosed bay named Omura. Especially, The Omura Bay has 53 small and medium size rivers around its coast, which discharge some materials polluting the bay such as sewage, industrial effluents, agricultural fertilizer, ect. All these materials make the bay overenriched with nutrients and this has been well known as cultural or man-made eutrophication. Therefore, water quality controlling and monitoring activities, recently, are inevitable. In this paper, we tried to research tidal current from the open sea to Omura Bay in other to obtain elementary data for Omura Bay's water purification using the remote sensing techniques. The field survey was carried out at three points with thermal infrared camera. And satellite data called Landsat-5/TM were applied to explain field data.
