Temporal and spatial analysis of suspended sediment distribution in the Amazon River using satellite imagery

Patterns of surface sediment concentration distribution in rivers are significant for understanding the broad ranges of fluvial environmental systems. In the case of the Amazon Basin, the complexity in the sediment pattern distribution is affected by the anabranching channel pattern of the Amazon River, the input by tributaries (some of which are among the largest rivers on earth) and the existence of huge and complex floodplains. Until recently, the assessment of sediment fluxes has been concentrated on hydro-sedimentological techniques in the Amazon Basin; however, efforts on characterizing the patterns of sediment transport have been neglected. This study aims to improve the understanding of the pattern of sediment distributions over a large scale in the Amazon River by estimating surface sediment concentration with remote sensing techniques. Field acquired surface sediment concentration values were supplied from three gauging stations representing the upstream, midstream and downstream sections of the Amazon River from 2000 to 2010 and calibrated with MODIS surface reflectance products (N=207, 232, 313, respectively). Empirical models were derived with robust causalities (0.63<R2<0.92) between field surface sediment concentration and surface reflectance from each station; however, sensitivity of reflectance around each stations were shown to be significantly affected by the local hydrological behaviors, leaving implications on analysis of the geomorphic characteristics affecting these associations. Overall, the capability of the remote sensing-based platform introduced in this study is successfully demonstrated by capturing the spatial and temporal variability of surface sediments in the Amazon River Basin, which is the largest and the most complex river system on earth.