The aims of the validation were:
•To generate quality controlled water-leaving radiance and reflectance, incorporating correction factors from the buoy platform and local conditions;
•To match the output with satellite data from the Sentinel-3 mission;
•To determine the uncertainty budget for individual parameters.
Optical and other environmental sensors were deployed on the buoy as part of the system, with data transmitted to the TechWorks Marine “CoastEye” data platform for inspection, processing, analysis and visualisation. The optical sensor system consisted of two pairs of up- and downwelling spectral radiometers positioned with a fixed depth separation in the water, with a fifth sensor mounted in air atop the buoy platform to measure the downwelling irradiance.
Significant work has been performed to experimentally measure and account for a range of effects, from tidal currents to buoy and instrument self-shading. A number of promising results have been measured, including measurement artefacts due to the “hyper-coastal” location of the deployment in a rapidly changing environment. Preliminary analysis indicates an excellent matchup between the in-situ CoastVal data and the Sentinel-3 data. Uncertainty budget calculations based on recent in situ and satellite data measurements are underway. These will be included in the in situ data processing chain so that the uncertainties for the observed water-leaving radiances can be calculated for the CoastVal system on an ongoing basis.
The project was reviewed by the European Space Agency in September 2018 and is presented on ESA's projects blog: