Data products generated by the Ocean Colour component of the European Space Agency Climate Change Initiative project. These files are daily composites of merged sensor (MERIS, MODIS Aqua, SeaWiFS LAC & GAC, VIIRS) products. MODIS Aqua and MERIS were band-shifted and bias-corrected to SeaWiFS bands and values using a temporally and spatially varying scheme based on the overlap years of 2003-2007. VIIRS was band-shifted and bias-corrected in a second stage against the MODIS Rrs that had already been corrected to SeaWiFS levels, for the overlap period 2012-2013. VIIRS and SeaWiFS Rrs were derived from standard NASA L2 products; MERIS and MODIS from a combination of NASAs l2gen (for basic sensor geometry corrections, etc) and HYGEOS Polymer v3.5 (for atmospheric correction). The Rrs were binned to a sinusoidal 4km level-3 grid, and later to 4km geographic projection, by Brockmann Consults BEAM. Derived products were generally computed with the standard SeaDAS algorithms. QAA IOPs were derived using the standard SeaDAS algorithm but with a modified backscattering table to match that used in the bandshifting. The final chlorophyll is a combination of OC4, Hu\s CI and OC5, depending on the water class memberships. Uncertainty estimates were added using the fuzzy water classifier and uncertainty estimation algorithm of Tim Moore. The reference website is http://www.esa-oceancolour-cci.org/