The peak near 700 nm on radiance spectra of algae and water: relationships of its magnitude and position with chlorophyll concentration

Abstract To investigate the nature of the peak near 700 nm on reflectance spectrum of water, simultaneous measurements of the reflectance spectra in the region of 400 to 750 nm and relevant water quality constituent concentrations (chlorophyll, dissolved organic matter and suspended matter) were carried out. The data set cover various trophic states of water bodies, all seasons and different climatic regimes. A shift of the peak position from about 680 nm up to 7l5 nm and an increase of the peak magnitude when chlorophyll concentration increased were observed. The magnitude and the peak position could be used as precise indicators and predictors for the phytoplankton concentration. It contributed significantly to the increase in the accuracy of the derivation of chlorophyll values from multispectral data.