Remote estimation of water clarity in optically complex estuarine waters

AVHRR satellite imagery was evaluated as a potential data source for monito ring light attenuation (K-PAR), as a measure of turbidity, in Pamlico Sound estuary, North Carolina. In situ water quality data and reflectance imager y collected on 10 different dates were used to calibrate a general optical equation relating satellite-derived reflectance (R-d), nominally R-(630 nm) to K-PAR. Additional spectral data (e.g., absorption, subsurface reflectan ce), related reflectance and K-PAR to changes in phytoplankton pigments, or ganic matter, and suspended sediments. Optically, Pamlico Sound, North Caro lina is dominated by scattering from suspended sediments, whereas the tribu tary rivers are dominated by absorption from both dissolved and particulate organic matter. A general relationship developed between R-d and K-PAR (r( 2)=0.72) in Pamlico Sound was found useful in a variety of environmental co nditions; however a relationship between R-d and suspended sediment concent ration was less robust, and affected by changing sediment characteristics. In the rivers, high and variable absorption in the visible wavelengths prec luded development of a relationship between R-d and K-PAR. The relationship developed between R-d and K-PAR in Pamlico Sound is similar to those deter mined for Delaware Bay and Mobile Bay in previous studies, suggesting possi ble broader regional application of algorithms for coastal bays and estuari es having similar sediment characteristics, with direct application to SeaW iFS data. Published by Elsevier Science Inc.