Evaluation of the VIIRS ocean color monitoring performance in coastal regions

Ocean color (OC) remote sensing has entered a new phase with the successful deployment of the Visible Infrared Imager Radiometer Suite (VIIRS) sensor aboard the Suomi National Polar-orbiting Partnership (SNPP) satellite. The representativeness and accuracy of the VIIRS geophysical products need to be assessed before a wide use of these data by the scientific community. As an integral part of the VIIRS sensor calibration and validation efforts, our group has been continuously monitoring the validity of the VIIRSʹs OC and atmospheric data stream through time-series in-situ data acquired at the observatory sites which are part of the AERONET-OC network. This paper addresses the preliminary evaluations of the VIIRS sensorʹs performance for retrieving OC data of typical coastal water environments, by carrying out time-series, as well as qualitative and quantitative match-up comparisons analysis between in-situ and satellite retrieved OC data. Initial time-series match-up comparisons carried out for a year period (January to December, 2012) show that VIIRS data exhibits strong temporal and statistical agreements with AERONET-OC data demonstrating a potential in enhanced coastal water monitoring from space. VIIRS data of two NASA-OBPG processing schemes which apply different vicarious calibration gains and NOAA-IDPS system are analyzed based on in-situ data of LISCO and WaveCIS AERONET-OC sites which are located in Long Island Sound and Gulf of Mexico respectively as well as OC retrievals of the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor aboard the Aqua satellite. The underlying cause of the discrepancies observed in VIIRS retrieved normalized water-leaving radiances is also investigated. Finally, as the NASA-OBPG and NOAA-IDPS processing schemes for ocean color data of the VIIRS sensor continue to evolve, the results underline the necessity for monitoring and assessing the validity and consistency of VIIRSʹ ocean color products, especially for coastal waters.