Environmental Monitoring and Assessment

, Volume 170, Issue 1, pp 231–244

Comparison of different semi-empirical algorithms to estimate chlorophyll-a concentration in inland lake water

Authors

    • State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and LimnologyChinese Academy of Sciences
  • Ronghua Ma
    • State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and LimnologyChinese Academy of Sciences
  • Jingping Xu
    • State Key Laboratory of Remote Sensing ScienceJointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University
  • Yuanzhi Zhang
    • Institute of Space and Earth Information ScienceThe Chinese University of Hong Kong
  • Bai Zhang
    • Northeast Institute of Geography and Agricultural EcologyChinese Academy of Sciences
Article

DOI: 10.1007/s10661-009-1228-7

Cite this article as:
Duan, H., Ma, R., Xu, J. et al. Environ Monit Assess (2010) 170: 231. doi:10.1007/s10661-009-1228-7

Abstract

Based on in situ water sampling and field spectral measurement from June to September 2004 in Lake Chagan, a comparison of several existing semi-empirical algorithms to determine chlorophyll-a (Chl-a) content was made by applying them to the field spectra and in situ chlorophyll measurements. Results indicated that the first derivative of reflectance was well correlated with Chl-a. The highest correlation between the first derivative and Chl-a was at 680 nm. The two-band model, NIR/red ratio of R710/670, was also an effective predictor of Chl-a concentration. Since the two-band ratios model is a special case of the three-band model developed recently, three-band model in Lake Chagan showed a higher resolution. The new algorithm named reverse continuum removal relies on the reflectance peak at 700 nm whose shape and position depend strongly upon chlorophyll concentration: The depth and area of the peak above a baseline showed a linear relationship to Chl-a concentration. All of the algorithms mentioned proved to be of value and can be used to predict Chl-a concentration. Best results were obtained by using the algorithms of the first derivative, which yielded R2 around 0.74 and RMSE around 6.39 μg/l. The two-band and three-band algorithms were further applied to MERIS when filed spectral were resampled with regard to their center wavelengths. Both algorithms showed an adequate precision, and the differences on the outcome were small with R2 = 0.70 and 0.71.

Keywords

Field spectralLake ChaganContinuum removalThree-band model

Copyright information

© Springer Science+Business Media B.V. 2009