Simulation and Sensitivity Analysis of Remote Sensing Reflectance for Optically Shallow Water Bathymetry

Optically shallow waters (OSW) enable water depth retrieval through passive optical remote sensing, benefiting from the relatively low attenuation of the water column. However, in OSW environments, remote sensing reflectance is influenced by multiple optical parameters beyond water depth. Comprehensive quantification of these influences remains necessary. This study utilizes numerical simulations to systematically categorize optical parameter ranges and perform variance-based sensitivity analysis. The results indicate that OSW parameter characteristics differ between extremely shallow and moderately shallow waters. In extremely shallow waters, water depth and bottom reflectance are the primary determinants of remote sensing reflectance, with longer wavelengths exhibiting greater sensitivity to depth variations. Bathymetric models utilizing long wavelength combinations demonstrate high accuracy in extremely shallow waters. In moderately shallow waters, sensitivity contributions for shallow water features are concentrated in the blue-green bands, whereas reflectance above 600 nm is primarily influenced by deep-water reflectance and noise, limiting the retrieval of depth and bottom reflectance. Simulations across OSW parameter ranges further reveal that the absolute error in depth estimation increases with depth, whereas relative error is more pronounced in extremely shallow waters compared to moderately shallow waters.