Evaluation of MODIS and SeaWiFs Ocean Color Algorithms in the Canadian Arctic Waters: The Cape Bathurst Polynya

During the 2004 Canadian Arctic Shelf Exchanges Study (CASES) field program, an extensive in situ bio-optical data set covering the Cape Bathurst polynya was acquired. This data set was used to evaluate the performance of the OC4v4 (SeaWiFS) and OC3M (MODIS) ocean color algorithms, and to develop locally tuned ones for that region that is affected by the presence of high concentration of colored dissolved organic matter (CDOM) that contaminates the reflectance signal. The OC4v4 and the OC3M algorithms overestimated in situ chlorophyll a by roughly a factor of four. The western Beaufort sea versions of the SeaWiFS algorithm (OC4L and OC4P) provided slightly better results but still highly overestimated chlorophyll. Our new regional algorithms showed a much improved performance (MNB=5.33%) allowing for a better estimation of the chlorophyll concentration.