Wave-derived coastal bathymetry from satellite video imagery: A showcase with Pleiades persistent mode

Abstract

This article shows the capacity do derive depth using the sub metric Pleiades satellite mission (Airbus/CNES) in persistent mode, which allows acquiring a sequence of images (12 images) at a regional scale (~100 km2). To derive depths, a spatiotemporal cross-correlation method for estimating wave velocity and inverse bathymetry is presented and applied to the 12-image sequence. A good agreement is found with in-situ bathymetry measurements obtained during the COMBI 2017 Capbreton experiment (correlation of 0.8, RMSE = 1.4 m). Depth estimate saturation is found for depths >35 m, mainly in a deep canyon just off the coast located in front of the entrance to Capbreton harbour. The image sequence is used to study the sensitivity of the number of images. The results show that the accuracy increases with the number of images in the sequence and with a fine resolution. Despite their noisy nature, newly available time-updated satellite bathymetries can be used to understand coastal evolution at several scales and improve risk mitigation strategies through modelling.