The use of inherent optical properties for determination of water quality

An attempt to estimate water quality parameters using Thematic Mapper (TM) data has been carried out in the coastal waters of Penang. The water quality parameters selected were total suspended solids (TSS) and chlorophyll concentrations. The algorithm used is based on the reflectance model which is a function of the inherent optical properties of water which can be related to its constituents concentrations. A multiple regression algorithm was derived using multiband data for retrieval of each water constituent. The digital numbers coinciding with the sea truth locations were extracted and converted to radiance and exoatmospheric reflactence units. Solar angle and atmospheric corrections were performed on the data sets. These data were combined for multi-date regression analysis. The efficiency of the present algorithm versus other forms of algorithms was also investigated. Based on the observations of correlation coefficient and root-mean-square deviations with the sea-truth data, the results indicated the superiority of the proposed algorithm. The solar corrected data gave good results, and comparable accuracy was obtained with the atmospherically corrected data. The calibrated TSS and chlorophyll algorithms were employed to generate water quality maps.