Remote sensing of vegetation based on band-spectral and hyperspectral studies at canopy and pigment level within visible range of wavelength

摘要

The suitability of visible spectral response of vegetation for remote sensing has been investigated with field and laboratory studies on canopy and chloroplastidial pigments, respectively. To simulate band-spectral and hyperspectral sensing, measurements were taken both in wavebands and with fine resolution of wavelength. Vegetation species and maturity stages were distinguished with average reflectance and characteristic absorption features. The methodology was tried on both land vegetation, viz. jute canopy of West Bengal and marine plant, viz. green algae of the eastern coast of India. The absorbance variation within visible wavelength range was observed with both mixed chlorophyll solution and solutions of chromatographically separated pigments. The different characteristic absorption peaks were identified, which were quite different for higher plants and algae. The gradual changes in spectral response of leaf pigments with senescence in a common higher plant were systematically investigated with both original leaf extracts and artificial mixtures of fresh and decomposed chlorophyll solutions at different ratios. Mathematical models were put forward for both average and hyperspectral absorption features to track the experimental plots and estimate absorption at different wavelengths.