ANALYSIS OF STORMY WAVE FIELDS AROUND RIVER MOUTH OBSERVED BY X-BAND RADAR

Abstract

 We measured the wave field around the mouth of Oii River, Yoshida City, Shizuoka Prefecture, with an X-band radar during stormy condition. Fourier transform is applied to the sequence of images, and the phase distribution map of the wave field is processed from the result. From this map, we determined the local wave lengths and directions, which depict the refraction process of the waves approaching the shore. We finally estimated the depth distribution of the area using the linear dispersion relationship with the wave length and frequency of the Fourier transform. The validity of the depth estimation is verified with survey results, which showed reasonable agreement. The proposed method in this study is more flexible than other methods, which use fast Fourier transform (FFT) regarding the choice of data length and frequency.