Comparison of Ocean Color Data Products from Meris , Modis , and Seawifs : Preliminary Results for the East China Seas

Concurrent Level-3 data products from MERIS, MODIS, and SeaWiFS between June 2003 and June 2006 for the East China Seas were compared against each other to evaluate the consistency between the sensors. The atmospheres in these regions is generally turbid, with typical aerosol optical thickness at 865 nm (tau_865) around 0.16, therefore presents a challenge to atmospheric correction. The statistical comparison focused on three geographical areas in the offshore waters that are influenced by the Kuroshio current with mean chlorophylla concentrations (chl) < 0.2 mg m (Area “a”), in the Zhejiang coastal waters where red tides often occur (Area “b”), and in the middle of the Yellow Sea (Area “c”), respectively. Except for the winter-spring blooms, the normalized water-leaving radiance (nLw_560), chl, and tau_865 data products were generally comparable among the sensors, particularly for Area “a”. RMS differences between MERIS and SeaWiFS, and between MERIS and MODIS increased from clear to turbid waters. Large discrepancies often occurred between tau_865 products.