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Proceedings Paper

Spectral features of reflectance and algorithm development for remote sensing of chlorophyll in Lake Kinneret
Author(s): Anatoly A. Gitelson; Yosef Z. Yacobi
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Paper Abstract

High resolution reflectance spectra, in the range from 400 to 850 nm, were acquired in Lake Kinneret during a period when dense populations of the dinoflagellate Peridinium gatunense dominated phytoplankton. Chlorophyll concentrations ranged from 5.1 to 185 mg.m-3 and from 2.4 to 187 mg.m-3 in the samples of two independent experiments. The most prominent features of the reflectance spectra were: 1) a wide minimum from 400 to 500 nm; 2) a maximum at 550-570 nm, which did not surpass 3% in samples with high chlorophyll concentration (> 20 mg.m-3), indicating a strong absorption by pigments in the green range of the spectrum; 3) a minimum at 676 nm. It was approximately 1%, and was almost insensitive to variation in chlorophyll concentration > 10 mg.m-3; and 4) a maximum reflectance showed near 700 nm. Its magnitude and position were highly dependent on chlorophyll concentration. High spectral resolution data were used as a guideline for the selection of the most suitable spectral bands for chlorophyll remote sensing. The ratio of the red reflectance maximum, near 700 nm, to the red minimum, near 670 nm, and also reflectance height above the baseline from 670 to 850 nm were used for construction of algorithms for chlorophyll determination. The best model, validated by independent data set, enabled estimation of chlorophyll concentration with an error of < 6.5 mg.m-3. For the purpose of chlorophyll mapping in Lake Kinneret, the use of three relatively narrow spectral bands was sufficient. Therefore, a relatively simple sensor, with only few bands will be employed in future applications for chlorophyll monitoring in inland waters. Radiometric data were also used to simulate radiances in the channels of TM Landsat and to find the algorithm for chlorophyll assessment. The ratio of channel 4 to channel 3 was used and enable chlorophyll estimation with an error of < 15 mg.m-3. This algorithm was used to map chlorophyll in the entire area of Lake Kinneret with 10 gradations.

Paper Details

Date Published: 21 September 1995
PDF: 12 pages
Proc. SPIE 2503, Air Toxics and Water Monitoring, (21 September 1995); doi: 10.1117/12.221099
Show Author Affiliations
Anatoly A. Gitelson, Ben-Gurion Univ. of the Negev (Israel)
Yosef Z. Yacobi, Israel Oceanographic & Limnological Research (Israel)


Published in SPIE Proceedings Vol. 2503:
Air Toxics and Water Monitoring
George M. Russwurm, Editor(s)

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