Monitoring inland waters with the APEX sensor, a wavelet approach

In this study a new curve fitting approach is presented to derive TSM, CHL and CDOM concentrations in inland and coastal waters from water leaving-reflectance spectra. The approach is based on the wavelet transform and is tested on simulated water-leaving reflectance spectra. For simulations SIOPS and water concentrations, representative for the Scheldt river, were used. The results shown that the approach is less sensitive to errors in the atmospheric correction or specific sensor noise. The idea is based on the development of a new minimization criteria for curve fitting. Instead of minimizing the difference between modeled and measured spectra using a simple RMSE, the RMSE is now combined with specific wavelet features. Several types of errors and noise are added to the simulated spectra to find robust features. Two minimization criteria were found which are almost insensitive to a white error and less sensitive to adjacency effects.