ALGORITHM FOR ATMOSPHERIC AND GLINT CORRECTIONS OF SATELLITE MEASUREMENTS OF OCEAN PIGMENT

An algorithm is developed to correct satellite measurements of ocean c olor for atmospheric and surface reflection effects. The algorithm dep ends on taking the difference between measured and tabulated radiances for deriving water-leaving radiances. The tabulated radiances are rel ated to the measured radiance when the water-leaving radiance is negli gible (670 nm). The tabulated radiances are calculated for rough surfa ce reflection, polarization of the scattered light, and multiple scatt ering. The accuracy of the tables is discussed. The method is validate d by simulating the effect of different wind speeds than that for whic h the lookup table is calculated, and aerosol models different from th e maritime model for which the table is computed. The derived water-le aving radiances are accurate enough to compute the pigment concentrati on with an error of less than +/-15% for wind speeds of 6 and 10 m/s a nd an urban atmosphere with aerosol optical thickness of 0.20 at lambd a 443 nm and decreasing to 0.10 at lambda 670 nm. The pigment accuracy is less for wind speeds less than 6 mis and is about 30% for a model with aeolian dust. On the other hand, in a preliminary comparison with coastal zone color scanner (CZCS) measurements this algorithm and the CZCS operational algorithm produced values of pigment concentration i n one image that agreed closely.