Analyze of the Inherent Optical Properties of French Guiana Coastal Waters for Remote Sensing Applications

The development of bio-optical algorithms to assess the spatio-temporal variability of Inherent Optical Properties (IOPs) and biogeochemical related components from space, is conditioned by our knowledge on these IOPs. The objective of this study is to characterize the IOPs and their relationships with biogeochemical parameters for the development of a future algorithm dedicated to the observation of the nearshore and offshore waters of the French Guiana from usual ocean color remote sensors. For that purpose, a set of IOPs and biogeochemical parameters was gathered from field measurements performed during a cruise achieved in the coastal waters of Cayenne in July 2006. The mean values of the mass specific non-algal absorption, (a(nap)(443)/SPM = 0.023 +/- 0.018 m(2)g(-1)), particulate scattering (b(p)(650)/SPM = 0.36 +/- 0.23 m(2)g(-1)) and backscattering (b(bp)(532)/SPM = 0.0065 +/- 0.0025 m(2)g(-1)) coefficients, as well as the a(nap)(lambda) spectral behaviors, are in good agreement with the fact the investigated waters are dominated by mineral particles. The relatively low particulate backscattering to scattering ratio value for such waters (0.014 +/- 0.004) could be explained by the presence of relatively large particles or aggregates with lower refractive index than pure mineral particles. This study shows that the chlorophyll concentration is largely overestimated with the standard OC4v4 algorithm.