Atmospheric correction of ocean color imagery: test of the spectral optimization algorithm with the Sea-viewing Wide Field-of-View Sensor

Abstract

We implemented the spectral optimization algorithm [SOA; Appl. Opt. 37, 5560 (1998)] in an image-processing environment and tested it with Sea-viewing Wide Field-of-View Sensor (SeaWiFS) imagery from the Middle Atlantic Bight and the Sargasso Sea. We compared the SOA and the standard SeaWiFS algorithm on two days that had significantly different atmospheric turbidities but, because of the location and time of the year, nearly the same water properties. The SOA-derived pigment concentration showed excellent continuity over the two days, with the relative difference in pigments exceeding 10% only in regions that are characteristic of high advection. The continuity in the derived water-leaving radiances at 443 and 555 nm was also within ~10%. There was no obvious correlation between the relative differences in pigments and the aerosol concentration. In contrast, standard processing showed poor continuity in derived pigments over the two days, with the relative differences correlating strongly with atmospheric turbidity. SOA-derived atmospheric parameters suggested that the retrieved ocean and atmospheric reflectances were decoupled on the more turbid day. On the clearer day, for which the aerosol concentration was so low that relatively large changes in aerosol properties resulted in only small changes in aerosol reflectance, water patterns were evident in the aerosol properties. This result implies that SOA-derived atmospheric parameters cannot be accurate in extremely clear atmospheres.