科研之友
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摘要
A hand-held spectrometer was used to collect above-water spectral measurements for measuring optically active water-quality characteristics of the Wabash River and its tributaries in Indiana. Water sampling was undertaken concurrent with spectral measurements to estimate concentrations of chlorophyll (chl) and total suspended solids (TSS). A method for removing sky and Sun glint from field spectra for turbid inland waters was developed and tested. Empirical models were then developed using the corrected field spectra and in situ chl and TSS data. A subset of the field measurements was used for model development and the rest for model validation. Spectral characteristics indicative of waters dominated by different inherent optical properties (IOPs) were identified and used as the basis of selecting bands for empirical model development. It was found that the ratio of the reflectance peak at the red edge (704nm) with the local minimum caused by chl absorption at 677nm was a strong predictor of chl concentrations (coefficient of determination (R-2)=0.95). The reflectance peak at 704nm was also a good predictor for TSS estimation (R-2=0.75). In addition, we also found that reflectance within the near-infrared (NIR) wavelengths (700-890nm) all showed a strong correlation (0.85-0.91) with TSS concentrations and generated robust models. Results suggest that hyperspectral information provided by field spectrometer can be used to distinguish and quantify water-quality parameters under complex IOP conditions.
- 出版日期2015-11-10
