Coastal Suspended Sediment Concentration Estimation using THEOS Satellite Imagery on the Chao Phraya River Mouth, Thailand

Abstract

Water quality monitoring is important to environmental control and ecosystem studies, which are not only scientifically relevant but also legally binding in several countries (e.g. the Water Framework Directive and the European Marine Strategy Framework Directive). Suspended sediment concentration (SSC) is one of the main parameters for water monitoring and can be roughly detected from satellite. In the present study, the Chao Phraya River mouth was used as a case study to assess measurement of levels SSC using spectral indices and THEOS satellite imagery. The THEOS satellite image of the Chao Phraya River mouth was taken on the same day with sea surface leaving radiance measured by spectrometer and water sampling for SSC determination. Sea surface radiance was converted to reflectance values to determine the relationship with SSC by applying to fourteen spectral indices from previous studies. The ratio ofRrs798 and Rrs532 was the spectral index with the best correlation to the observed SSC (R2 = 0.7598).THEOS satellite image was used in the estimation of SSC by applying the best spectrometer index to the satellite data. The ratio of Band4/Band2fromTHEOSbands provided the best estimation for this SSC parameter by R2 =0.6189.