Automating Nearshore Bathymetry Extraction from Wave Motion in Satellite Optical Imagery

Abstract

Nearshore depths for Waimanalo Beach, HI, are extracted from optical imagery, taken by the WorldView-2 satellite on 31 March 2011, by means of automated wave kinematics bathymetry (WKB). Two sets of three sequential images taken at intervals of about 10 seconds are used for the analyses herein. Water depths are calculated using a computer program that registers the images, estimates the currents, and then uses the linear dispersion relationship for surface gravity waves to estimate depth. Depths are generated from close to shore out to about 20 meters depth. Comparisons with SHOALS LIDAR bathymetry values show WKB depths are accurate to about half a meter, with R2 values of 90%, and are frequently in the range of 1020 percent relative error for depths ranging from 216 meters.