Landsat-8 is a new satellite that provides regular high resolution imagery of land and coastal waters around the world. OD Nature researchers have recently developed a new marine application for this imagery: the detection of black suspended sediments, for example those relocated by dredging operations.
The scattering of light by air molecules and aerosols changes what the satellite sees at the top of the atmosphere. Correction for these atmospheric effects is an essential step before satellite imagery can be used for water applications. The new atmospheric correction developed at RBINS is based on the assumption that water completely absorbs light in the shortwave-infrared (SWIR) bands of Landsat-8. Results show a very good separation of marine and atmospheric signals, and illustrate the value of high resolution imagery and high quality SWIR bands in coastal waters. Different colours are observed in the suspended sediments in the Belgian coastal zone, and these colours relate to origin of the sediment.
The Zeebrugge harbour needs to be dredged regularly to keep it navigable. The dredged material is coloured black due to the high organic matter content and anaerobic conditions. The material is disposited at designated dumping sites. Thanks to the atmospheric correction for the high quality images from Landsat-8, these black dredged sediments can easily be detected, and monitored from space.
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