Satellite Bathymetry

Satellite bathymetry is the estimation of shallow-water depth from optical satellite imagery, exploiting that light attenuates with depth at a wavelength-dependent rate through the water column. Empirical and physics-based models relate the blue, green, and near-infrared band radiances of sensors such as Landsat OLI and Sentinel-2 to depth, with root-mean-square error generally under 2 m to roughly 30 m in clear water. Accuracy falls in turbid water, over dark bottoms, and at depth. Satellite-derived bathymetry fills survey gaps in remote reef and coastal areas but does not meet IHO S-44 orders for safety-of-navigation charting on its own.