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Isolation of optical signatures of phytoplankton pigments in turbid productive waters: Remote assessment of chlorophyll-a
Abstract
Field-based collection of discrete measurements and laboratory analysis of water samples is the traditional methodology for monitoring the quality of turbid productive inland lakes. Despite its widespread use, this methodology can be limited by time and financial constraints when time-series of data are required over vast geographic regions. Remote sensing of lake water quality has the potential to overcome these limitations by complementing traditional monitoring techniques. The main objective of this study was to develop robust remote-sensing algorithms for estimating chlorophyll-a concentration (Chl) in turbid productive waters. A large set of reflectance and absorption spectra as well as relevant water quality parameters was collected over a period of three years in Nebraska lakes of different origins and morphometrics. A conceptual model originally developed for remote sensing of terrestrial vegetation, was tuned according to the optical characteristics of turbid productive waters and successfully used to predict Chl of independent data sets. The model relates Chl to a combination of three reflectance bands located in the red and near-infrared (NIR) spectral regions. NIR-to-red reflectance ratios can be viewed as a special case of this model. By means of simulated reflectance spectra, the sensitivity of these algorithms to variations in bio-optical parameters and reflectance uncertainties was studied. It was shown that the accuracy of Chl estimation depends strongly on the phytoplankton specific inherent optical properties as well as on reflectance uncertainties. On the other hand, the algorithms appeared to be robust with respect to variations in other bio-optical parameters such as the concentration of total suspended particles and the Chl fluorescence quantum yield. Finally, the potential of applying NIR-to-red reflectance ratios to existing ocean color sensors was demonstrated.
Subject Area
Environmental science|Optics|Biophysics|Limnology|Remote sensing
Recommended Citation
Dall'Olmo, Giorgio, "Isolation of optical signatures of phytoplankton pigments in turbid productive waters: Remote assessment of chlorophyll-a" (2006). ETD collection for University of Nebraska-Lincoln. AAI3208053.
https://digitalcommons.unl.edu/dissertations/AAI3208053