Satellite-derived Bathymetry Prediction in Shallow Waters Using the Gravity-Geologic Method: A Case Study in the West Sea of Korea

摘要

The Satellite Altimetry-Derived Free-air Gravity Anomalies (SAFAGAs) are correlated with undulations of crustal density variations under the seafloor. In this study, shipborne bathymetry from the Korea Rural Community Corporation (KRC) and the SAFAGAs from Scripps Institution of Oceanography were combined to predict the bathymetry in shallow waters near shore around Saemangeum Seawall located on the southwest coast of the Korean Peninsula. The density contrast of 5.0 g/cm(3) estimated by the checkpoints of the Gravity-Geologic Method (GGM) between the seawater and the seafloor topographic mass was applied to predict the bathymetry in shallow waters. The root mean square error of the bathymetry differences between GGM and KRC on the KRC shipborne tracks in shallow waters around Saemangeum Seawall is 0.6 m. The advantages of GGM in the short-wavelength components from the results of the power spectral density and coherency analysis in shallow waters proved that the satellite-derived bathymetry by GGM is highly correlated with shipborne bathymetry. The topographic effects in the off-tracks extracted from the SAFAGAs in GGM can be effectively utilized to improve the bathymetry by combining them with the shipborne depth data in shallow waters, where the shipborne depth data are limited.