Surface suspended matter off the Rhone river mouth from visible satellite imagery

The quantification of surface Total Suspended Matter (TSM) off the Rhone ri ver mouth is investigated using SPOT-XS and Landsat-TM images collected in November 1994. The method of satellite data calibration from in situ measur ements is discussed. It is based on TSM concentration measurements through filtration of surface water samples and on radiometric data collected with a 256-channel spectroradiometer in the range 400-1100 nm. Empirical relatio nships between reflectance and TSM concentration are established by linear regression analysis of the data. These relationships are then applied to th e image data corrected from atmospheric and surface effects. A good agreeme nt, within a factor of less than two, was found on derived TSM concentratio n values as compared with sea truth data. The results for three different r iver flows are presented: a quasi-normal-river discharge, a flood situation and an intermediate situation. The TSM corresponding concentration maps ar e presented and discussed. (C) Elsevier, Paris.