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In this paper the basic mechanisms which influence the spectral properties of vegetation, soil and water in the visible, near- and middle-infrared wavelengths are described in detail. Reflectance from a vegetation canopy varies both with wavelength and with the growth and development of the plants. Absorption by pigments controls plant reflectance in the visible wavelengths, leaf structure is the dominant factor in the near-infrared and, in the middle-infrared, absorption by water in the leaf is most important. Soil reflectance is less variable. All soils generally show an increase in reflectance with increasing wavelength, particularly at visible and near-infrared wavelengths. Increasing moisture content, iron oxide content and organic matter content reduce soil reflectance in all wavelengths considered, with water absorption having a particularly pronounced effect in the middle-infrared. Most spectral information concerning water characteristics is gleaned from the visible wavelengths, although the land/water boundary is most obvious in the infrared. The blue/green wavelengths are best for bathymetric studies in clear water, and for the mapping of phytoplankton rich waters. The green/red wavelengths are best for detecting inorganic sediments.

Additional information

Authors: BELWARD A S, JRC Ispra (IT)
Bibliographic Reference: Paper presented: Remote Sensing and Geographical Information Systems for Resource Management in Developing Countries, Ispra (IT), May 14-25, 1990
Availability: Available from (1) as Paper EN 36535 ORA
Record Number: 199210089 / Last updated on: 1994-12-02
Original language: en
Available languages: en