Depth Inversion Using SAR and Super-Resolution Enhancement: A Case Study on Case II Waters

Depth inversion is crucial for ocean exploration, with synthetic aperture radar (SAR) technology being a key tool due to its all-weather capabilities. However, SAR-based depth inversion typically has limited resolution, ranging from hundreds to thousands of meters, which restricts its use in fine-scale underwater topography studies. Therefore, we introduce super-resolution enhancement (SRE) technology to improve SAR-based depth inversion. Using the Case II waters off California coastline as a case study, we pair low-resolution ETOPO data with high-resolution multibeam data, employing the residual channel attention network (RCAN) to construct a depth SR model. Our key findings demonstrate that in these Case II waters, the SR model successfully enhances resolution from 180 m to 90 m, achieving SSIM > 0.94, PSNR > 16.0dB, and significantly improved accuracy (average RMSE: 4m, MRE: 11.9%) compared to SAR direct inversion (RMSE: 5.4-8.3m, MRE: 16.8-21.3%). The method we proposed indicates the integration of SAR- based depth inversion and SRE technology effectively retains original information while enhancing both spatial resolution and accuracy, demonstrating its efficacy in complex marine environments and providing a novel and effective method for high-resolution marine surveying, thereby expanding SAR's application potential in marine sciences.