Inherent optical properties and satellite retrieval of chlorophyll concentration in the lagoon and open ocean waters of New Caledonia

The retrieval of chlorophyll-a concentration from remote sensing reflectance (Rrs) data was tested with the NASA 0C4v4 algorithm on the inner New Caledonian lagoon (Case 2) and adjacent open ocean (Case 1) waters. The input to 0C4v4 was Rrs measured in situ or modeled from water's inherent optical properties (2001-2007). At open ocean stations, backscattering and absorption coefficients were correlated with chlorophyll (R-2 = 0.31-0.51, respectively), in agreement with models for Case 1 waters. Taking spectrofluorometric measurement as reference, the 0C4v4 model leads to an average underestimation of 33% of the chlorophyll concentration. For the lagoon waters, 0C4v4 performed inadequately because the backscattering coefficient, highly correlated with turbidity and suspended matter (R2 = 0.98), was poorly correlated to chlorophyll (R-2 = 0.42). The 0C4v4 performance was better in deep lagoon waters for stations with a TOT index (Tchla x depth/turbidity) higher than 19 mg M-2 NTU-1 (R-2 = 0.974, bias = 10.2%). Global Imager Rrs provided a good estimate of Tchla (R-2 = 0.79, N = 28) in the deeper part of the lagoon. (C) 2010 Elsevier Ltd. All rights reserved.