ACOLITE FOR SENTINEL-2: AQUATIC APPLICATIONS OF MSI IMAGERY

摘要

Here we present the application of Sentinel-2 imagery for coastal and inland waters, and the ACOLITE processor and atmospheric correction developed in the EC-FP7 HIGHROC project. The MultiSpectral Imager (MSI) on board of Sentinel-2 has a pair of 20 m SWIR bands at 1.6 and 2.2 μm, allowing for a robust image-based atmospheric correction, even over extremely turbid waters. One of the main advantages of Sentinel-2 over Landsat-8 is the inclusion of a 20 m resolution red-edge band at around 705 nm, allowing for the determination of chlorophyll a absorption in turbid and productive waters, where open ocean blue-green ratio algorithms fail. MSI has red (665 nm) and NIR (842 nm) bands at 10 m spatial resolution, allowing for the retrieval of turbidity or suspended particulate matter concentration, even in narrow inlets and ports. This makes it an invaluable dataset for validating sediment transport models that are needed for optimization of dredging operations and coastal defence around ports. The spectral, spatial, and radiometric resolutions of Sentinel-2 and Landsat-8 are compared and discussed. For many aquatic applications these missions will typically be combined as a virtual constellation to improve temporal coverage. We provide here one example of using both sensors to track a cyanobacterial bloom in an Australian lake.