Internal Wave Observation in Southwest Coast of Japan

This research deals with internal waves observation around southwest coast of Japan by using ERS-1/2 SAR and Topex/Poseidon (T/P) images during 1993-2002 period. Proposed method consisting of Symlet wavelet analysis and Canny edge detector can detect internal wave in SAR image. Internal waves were detected with higher wavelet coefficient than sea surface on horizontal and vertical detail coefficient of image transforms at level-3 and appear as elongated pattern in image. The monitoring results such as location, time and wavelength are compiled in database to understand the nature of internal wave and can be used for the prediction of internal wave in this area. Sea level anomaly data and absolute dynamic topography data derived from T/P images are used to analyze the oceanic condition where internal wave occur. The result shows that the internal waves were mostly occurred at north coast of Kitakyushu and NW/W/SW/E coast of Tsushima Island on June to September period. The directions of propagation were varies to NW-SW at eastern channel and N-SW at western channel of Tsushima Strait. These areas coincide with T/P data where sea level anomaly increase steeply. KeywordsSAR image, Topex/Poseidon image, internal wave detection, wavelet analysis