EFFECT OF SUSPENDED SEDIMENT DISTRIBUTION ON SPECTRALREFLECTANCE

摘要

Remote sensing techniques have been used extensively to estimate water quality parameters in lakes. Sensorswith a wide variety of spectral, spatial, and temporal resolutions, and mounted on an assortment of platforms includingsatellites and aircrafts have been used to evaluate chemical pollutants, suspended solids, and chlorophyll abundance.However, methods developed to estimate water quality parameters are based mainly on assumption of uniform distribution ofpollutants along the depth. In actuality suspended sediments are not distributed uniformly along the depth. This study wasdone with the objective of determining effect of non- uniform distribution of suspended sediments on remotely sensedsignals. This study was done in laboratory conditions using water in a black lined experimental tank. Spectral distribution ofwater body reflectance was measured for constant amount of sediment. Sediments were mixed in water tank uniformly andmeasurements of spectral signature were done with time as sediments settled. A dual sensor Spectro-radiometer was used tomeasure relative reflectance in the electromagnetic spectrum region of 346.08 nm to 1000.28 nm (456 channel), withbandwidth of approximately of 1.438 nm. Reflectance is found to vary with time for the same concentration of sedimentswith time of sedimentation. These results indicate that the sediment distribution affects the reflectance values.