Assessment of Suspended Sediments Concentration in Surface Waters, Using Modis Images

Abstract

Remote sensing from air-borne and space-borne sensors have proved to be a useful method for Suspended Sediment Concentration (SSC) estimation as it provides an instantaneous and synoptic view of suspended sediments that would otherwise be unavailable. The reason for the success of remote sensing in such surveys is the strong positive relationship that exists between SSC and remotely sensed water leaving radiance. To find an algorithm relating SSC to spectral radiance over Bahmansheer River Estuary at the North-West of Persian Gulf, a three-month field expedition (April to June 2003) was conducted while the MODIS sensor on board Terra simultaneously flew over the scene. Fifty seven samples in fifteen trips were collected. The collected samples were analyzed by measuring concentration, diameters of the sediment particles and by determining the sediment constituents. Total concentration ranged between 30 and 500 mg, the range of particle diameter was from less than a micrometer to more than 20 micrometers and finally it was found that the sediment was composed of Quartz, Kaolinite, Orthoclase, Chlorite, Calcite, Gypsum, Muscovite, Halite, Anhydrite, Apatite, Biotite and a low amount of Albite. It is found that the spectral characteristics of these compositions are partly responsible for the reflected and/or scattered energy in different bands while the correlation between larger suspended particle concentration and spectral radiance was profound.