Novel algorithms for remote sensing of chlorophyll content in higher plant leaves

The general features of reflectance spectra of higher plant leaves are considered with special reference to remote sensing of chlorophyll. Wavelengths with maximum sensitivity to chlorophyll content were found in the wide spectral range from 550 to 630 nm and near 700 nm. The wavelength of the red edge position of the reflectance spectrum correlated very closely with the reflectance at 550 and 700 nm. The ratios of reflectances in the near infra-red range of the spectrum (above 750 nm) to that at 700 nm R/sub NIR//R/sub 700/ and R/sub NIR//R/sub 550/ were directly proportional to the leaf chlorophyll content. Newly introduced algorithms make it possible precise chlorophyll estimation (with an error of less than 5 nmol/cm/sup 2/) and probably could be applied to a number of plant species. They exhibit more than 6 times wider dynamic range than the widely used Normalized Difference Vegetation Index.