Monitoring water constituents and salinity variations of saltwater using EO-1 Hyperion satellite imagery in the Pearl River Estuary, China

Abstract

to detect water constituents' concentrations and salinity of the Pearl River Estuary (PRE), we analyzed the spectral properties of water constituents and investigated the relationships between field water reflectance spectra and water constituents' concentrations based on the synchronous in-situ hyper-spectral data analysis. Two strong relationships were discovered (two linear fit described respectively the positive correlation), one between in-situ reflectance ratio R680/R527 and total suspended sediment concentrations (TSS) (R2=65%) and the other between chlorophyll-a concentrations and the reflectance ratio R704/R513 (R2=78%); however, the result also showed that the absorption coefficient of color dissolved organic matter (CDOM) was not tightly correlated with reflectance. In addition, we also observed the significant relationships (R2=79%) between TSS and surface salinity. Finally, we were able to develop a novel method to detect water constituents' concentrations and surface salinity of river estuary waters from the calibrated EO-1 Hyperion reflectance data in the PRE. The EO-1 Hyperion derived surface salinity and water constituents' concentrations were validated using in-situ data that were collected on December 21, 2006, and synchronous with EO-1 Hyperion satellite imagery acquisition. The results showed that the semi-empirical relationships are capable of predicting salinity and water constituents' concentrations from EO-1 Hyperion imagery.