Modelling the spectral absorption of tripton using exponential and hyperbolic models
Abstract:The optical properties of tripton, and the correlation between the absorption coefficient and tripton concentration, were investigated based on a large dataset of 727 samples, collected from different regions of shallow Lake Taihu, in China, from July 2004 to April 2007. Four models describing tripton absorption spectra in the visible domain (400–700 nm) were examined to find the optimal model. The conventional single exponential model performed the poorest. Statistically, the most ‘useful’ model was the hyperbolic model; judged by the root mean square error (RMSE) and the magnitude of the F statistic from an analysis of variance, this was found to give a closer fit for the measured absorption (70.1% reduction in RMSE and 449.7% increase in F value) than did the simple exponential model method. The mean S d value derived for the hyperbolic model was 5.98 ± 0.30 nm–1, with a very small coefficient of variation of 5.0%. Significant linear correlations were found between a d(440) and total suspended matter, inorganic suspended matter and tripton concentrations, but with the minimal RMSE of a d(440) estimation (0.815 m–1) for tripton. The results demonstrate that it is possible to develop regional models for the estimation of tripton absorption coefficient from the concentration.
Document Type: Research Article
Affiliations: Taihu Lake Laboratory Ecosystem Research Station, State Key Laboratory of Lake Science and Environment,Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing RoadNanjing210008, PR China
Publication date: July 20, 2011