Reflectance in the red and near infra-red ranges of the spectrum as tool for remote chlorophyll estimation in inland waters-Lake Kinneret case study

Signature analysis of reflectance spectra was used for the selection of the most suitable spectral bands for remote sensing of chlorophyll in inland waters. The parameters of the reflectance peak near 700 nm were employed for construction of algorithms for chlorophyll determination. The best model, validated by independent data sets, enabled estimation of chlorophyll concentration with an error <0.6 mg/m/sup 3/ for period of low Chl concentration and <6.5 mg/m/sup 3/ for period of the phytoplankton bloom. For the purpose of chlorophyll mapping in Lake Kinneret, the use of three relatively narrow spectral bands was sufficient. Radiometric data were also used to simulate radiances in the channels of TM Landsat and to find algorithm for chlorophyll assessment. The ratio (TM2-TM3)/TM1 was used to retrieve chlorophyll in the range 3-10 mg/m/sup 3/ with an error of <1 mg.m/sup -3/; the ratio TM4/TM3 was used to map chlorophyll in the range 10-200 mg/m/sup 3/ with 10 gradations.