Tracking mud banks on the 1500 km coastline from the Amazon to the Orinoco Delta

Currents transport the sediment discharge of the Amazon River as far as the Orinoco Delta (Venezuela).  The combined actions of waves (predominately from the NE) and the Guiana Current create mud banks of 30 km in width.  A continuous process of mud erosion and accretion propagates the mud banks westward  

The talk demonstrates tracking the mud banks with satellite-derived bathymetry (SDB).  The SDB method used here is not the familiar Lyzenga bottom radiance to depth inversion which works only in clear waters.  Here there is no bottom visibility.  Instead, the SDB uses the interaction of ocean waves with the bottom.  Ocean waves exhibit refraction, slower celerity, and reduced wavelength as they ‘feel’ the bottom.   These phenomena are observable regardless of water turbidity.

WKB has been successfully implemented with X-band radars on coastal towers and ships (by German and UK researcher groups); and with the WorldView and Pleiades satellites (by this author and others).  However, all these sensor modalities have small ground footprints (~10 km² to 100 km²).

The European Sentinel-2 satellites have dramatically increased WKB coverage to a regional scale.  This talk presents a Sentinel-2 view of the 1500 km muddy coastline, extending up to 50 km offshore (a total area of 75,000 km²).    

The leap in WKB possibilities was made possible by a 220 km image swath, repeat visits every five days, and the free distribution of the images from the Copernicus portal.