Consistency between Satellite Ocean Colour Products under High Coloured Dissolved Organic Matter Absorption in the Baltic Sea

• Published in: Remote Sensing
• Main Authors: Gavin H. Tilstone, Silvia Pardo, Stefan G. H. Simis, Ping Qin, Nick Selmes, David Dessailly, Ewa Kwiatkowska
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2021
• Subjects: Sentinel-3; OLCI; validation; remote sensing reflectance; atmospheric correction; Baltic Sea; Science; Q; Aerosol Robotic Network
• Online Access: https://doi.org/10.3390/rs14010089; https://doaj.org/article/e72336a4e4ec464ea649843cfbb984db

Ocean colour (OC) remote sensing is an important tool for monitoring phytoplankton in the global ocean. In optically complex waters such as the Baltic Sea, relatively efficient light absorption by substances other than phytoplankton increases product uncertainty. Sentinel-3 OLCI-A, Suomi-NPP VIIRS and MODIS-Aqua OC radiometric products were assessed using Baltic Sea in situ remote sensing reflectance ( <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>R</mi><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math> ) from ferry tracks (Alg@line) and at two Aerosol Robotic Network for Ocean Colour (AERONET-OC) sites from April 2016 to September 2018. A range of atmospheric correction (AC) processors for OLCI-A were evaluated. POLYMER performed best with <23 relative % difference at 443, 490 and 560 nm compared to in situ <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>R</mi><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math> and 28% at 665 nm, suggesting that using this AC for deriving Chl a will be the most accurate. Suomi-VIIRS and MODIS-Aqua underestimated <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>R</mi><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math> by 35, 29, 22 and 39% and 34, 22, 17 and 33% at 442, 486, 560 and 671 nm, respectively. The consistency between different AC processors for OLCI-A and MODIS-Aqua and VIIRS products was relatively poor. Applying the POLYMER AC to OLCI-A, MODIS-Aqua and VIIRS may produce the most accurate <math xmlns="http://www.w3.org/1998/Math/MathML" ...