WorldView-2 bathymetric capabilities

The capability of the WorldView-2 (WV02) satellite is analyzed for bathymetric applications in shallow coastal waters. We use an Optimal Estimation method, which provides lower bounds on retrievals errors for an idealized sensor and idealized model of the environment. Retrieval performance is studied over different substrates and column water properties. We also study effects of increased signal to noise ratio. This analysis is supported by numerical inversion of imagery, using a variant of a least-square optimization. Results from 4 different study areas collected across a few sites in clear Case 1 and Case 2 waters show that the water depth can be realistically measured on a pixel-by-pixel basis with 10% standard deviation of the error, down to nearly 20 meters depth in Case 1 waters over bright sandy bottom. The same accuracy over dark sea grass or coral is valid down to 10 meters, assuming that reliable <i>a priori </i>substrate albedo is available. Water turbidity has an important effect on retrievals - Case 2 water with small concentrations of suspended solids allows for 10% accuracy down to 10 meters over bright targets. The retrieval accuracy is likely to improve with tighter a priori constrains, constraints obtained from the context of entire image, or independent information from multiple stereo pairs collected in a single WV02 pass.