Relationships between chlorophyll and ocean color constituents as they affect remote‐sensing reflectance models1

Good agreement between satellite‐derived and shipboard measurements of chlorophyll a + pheophytin a concentrations results from the covariance of each of the nonwater color constituents of the ocean with pigment concentration. The specific absorption coefficient at 440 nm varies directly with the submicron chlorophyll fraction, which itself varies inversely with total chlorophyll concentration. Both the backscattering coefficient for particles and the Gelbstoff absorption coefficient increase with chlorophyll pigments. An analytical remote‐sensing reflectance model for chlorophyll concentrations in the eastern Gulf of Mexico is developed from these relationships and tested against an independent data set. By this approach, remote‐sensing algorithms can be developed that respond to regional and seasonal differences in runoff (e.g. terrigenous Gelbstoff and detritus), phytoplankton size, and pigment color groups.