New opportunities and challenges for high resolution remote sensing of water colour
Oral presentation. Proceeding of Ocean Optics XXIII Conference. Victoria (BC), Canada. 23 – 28 Oct., 2016.
The last two years have seen a dramatic increase in the applications of optical remote sensing for turbid coastal and inland waters, driven largely by the availability of free, high quality and high resolution satellite data from Landsat-8 and Sentinel-2. It is now possible to regularly and systematically map the distribution and dynamics of suspended particles and certain impacts of human activities close to shore and inside ports, estuaries and inland waters. Commercial missions such as Pléiades, Worldview and Rapideye also offer new possibilities for remote sensing of aquatic processes at even higher spatial resolutions (~1m). The exploitation of such data brings new algorithmic challenges and opportunities including: the use of SWIR bands for atmospheric correction in turbid waters; the challenge of lower signal:noise specifications and possible spatial binning techniques; the exploitation of extremely high resolution panchromatic bands; the assessment of the impact of sub-pixel scale effects for medium resolution ocean colour missions; the need to remove/filter sunglint and surface wave effects; the possibility to resolve patchy distributions (suspended matter, surface foam, algal blooms, floating vegetation, etc.); problems of data contamination by cloud and object shadows; and the validation of narrow swath sensors. The state of the art of high resolution remote sensing of water colour is reviewed here and the many emerging opportunities and algorithmic challenges are outlined using examples from Landsat-8, Sentinel-2 and Pléiades