METHOD FOR THE QUANTIFICATION OF SUSPENDED SEDIMENTS FROM AVHRR NOAA-11 SATELLITE DATA

Occanographic data (Ecofer, Givapa and Gastel cruises) and satellite images evidence that the channels 1 and 2 (visible and near infra-red regions) of AVHRR/NOAA-11 can be used to estimate the total concentration of suspended sediments on the sea surface, with a daily frequency when under cloudless skies. The near infra-red channel is used for atmospheric corrections. The fit function obtained between the concentrations determined by filtration and the corrected satellite data is linear between 0-5 mg l-1 and 10 mg l-1. The satellite data are also compared to ship data scattering measurements. The results match. This fit function is applied to each satellite value to obtain the estimated concentration. The total weight of the suspended sediments is calculated by multiplying each of the estimated concentrations by the area and by the number of pixels. The relative errors are evaluated to provide an interval of accuracy. This method is applied to the inshore continental shelf off the mouth of the Gironde estuary (France).