Shallow water bathymetry with an incoherent X-band radar using small (smaller) space-time image cubes

The approach most commonly used in bathymetry by “depth inversion” starts by transforming a space-time cube of ocean surface images into a wavenumber-frequency spectrum. The depth is determined by fitting the shallow water gravity wave dispersion equation to the 3D spectrum. The depth error using this method is inversely proportional to the image cube size. Very large image cubes are required for accurate bathymetry. Typical cube dimensions are on the order of 250 m × 250 m × 100 s. A new algorithm, originally developed for satellite images, can achieve the same accuracy with much smaller cubes, on the order of 100 m × 100 m × 10 s. This paper describes a test of this algorithm on low grazing angle radar data. The algorithm offers the potential for rapid near shore bathymetry surveys using marine X-band radars flown on aircraft.