Ocean Dynamics

, Volume 53, Issue 2, pp 98–102

Spectral reflectance measurements of estuarine waters

Authors

  • Karl-Heinz Szekielda
    • The Graduate Center, PhD Program in Earth and Environmental Sciences, NOAA/CREST, City University of New York and Columbia University e-mail: szekielda@aol.com
  • Christopher Gobler
    • Long Island University, Southampton, New York
  • Barry Gross
    • Cooperative Remote Sensing Science and Technology Center (NOAA/ CREST), City College of the City University of New York
  • Fred Moshary
    • Cooperative Remote Sensing Science and Technology Center (NOAA/ CREST), City College of the City University of New York
  • Samir Ahmed
    • Cooperative Remote Sensing Science and Technology Center (NOAA/ CREST), City College of the City University of New York

DOI: 10.1007/s10236-003-0027-x

Cite this article as:
Szekielda, K., Gobler, C., Gross, B. et al. Ocean Dynamics (2003) 53: 98. doi:10.1007/s10236-003-0027-x

Abstract

 Shapes and variations of reflectance spectra in estuarine water were investigated for the purpose of monitoring chlorophyll in situ by optical means. A survey undertaken in an estuarine environment, using reflectance measurements between 400 and 850 nm with a full-width half maximum (FWHM) of about 2 nm, revealed that the first derivative in the neighbourhood of the chlorophyll absorption band shows a defined spectral region which can be used to estimate chlorophyll concentrations. Correlation between chlorophyll and the first derivative was found to be low, but a good relationship exists between the ratio of the reflectance R680/R670 and chlorophyll concentrations. Based on dissolved organic carbon measurements, it is assumed that chromophoric dissolved organic compounds mask the absorption band of chlorophyll in the blue part of the spectrum, resulting in a low correlation coefficient in that spectral range. Therefore, the use of the red bands is an alternative for measuring photosynthetic pigments in coastal water at longer wavelengths. Results presented here demonstrate that the spectral locations of bands in the visible are not adequate and that hyperspectral data are required for positioning the very narrow bands for measuring chlorophyll at longer wavelengths.

Keywords Spectral reflectanceEstuarine waterChlorophyll

Copyright information

© Springer-Verlag Berlin Heidelberg 2003