Comparison of water depth detection results with SAR and TM images in Taiwan Shoal

Abstract

Water depth of the shallow water area can be reflected in SAR (Synthetic Aperture Radar) imagery and TM imagery. The water depth can be detected by SAR and by TM. The water depth SAR detection is based on the mathematical model describing the movement of tidal current and the interaction between the Radar's microwave and the micro-scale waves in the sea surface. The water depth TM detection is based on the relation between the water depth and the gray value of TM image. In order to testify the capability of the water depth detection by SAR and by TM, one area in Taiwan Shoal, which locates in 118.55°~118.75°E, 23.0°~23.3°N, is taken as the study area for the water depth detection by SAR and by TM. The detection results shows that SAR image and TM image also can be used in the water depth detection, but the detection results by SAR is better than by TM and the largest water depth detected by SAR is larger than by TM. The water depth TM detection result based on several typical real water depths includes the large-scale information of underwater topography, and this can be used in the water depth SAR detection as the initial water depth. A new water depth detection method combing SAR image, TM image and several typical real water depths is concluded.