Evaluation of Albedo as an Indicator of Land Degradation Using Digital Image Processing R. JANA, M.V. KHIRE and G. SAJEEVAN * Centre of Studies in Resources Engineering (CSRE), Indian Institute of Technology, Bombay 400076 * Centre for Development of Advanced Computing (C-DAC), Pune University Campus, Pune 411007 rina@csre.iitb.ernet.in Abstract As dry land is most sensitive to land based environmental degeneration a spatial attention is required for the study of land degradation. Albedo is a physical parameter of the land, which can delineate the land use/land cover characteristics due to flash flood, soil erosion, soil moisture, vegetation and loss of primary productivity of the land. Here an attempt is taken to evaluate change in albedo of land surfaces using IRS LISS-I data and digital image processing technique. The evaluated change in albedo is also indexed to delineate the degree of land degradation. 1. Introduction The land degradation is a process of degeneration of land characteristics with respect to its primary productivity. It is a land based environmental degradation and it needs urgent scientific attention as population pressure on land based resources is increasing sharply. The environmental degradation of the land surface or land degradation in short, is predominant in arid and semiarid zone, as dry land is most sensitive to the changes due to both natural and manmade stress (Ghosh, 1992). There are a number of physical, biological, ecological and socio-economic parameters to evaluate degeneration of land. Further, the degree of degeneration can be delineated by indexing and integrating such parameters. Albedo is a spectral property of the earth's surface and defined as the percentage of the solar radiation reflected by an object to the amount incident on it. It can be estimated from remotely sensed data collected from surface of the earth. The change in albedo can be used as a physical indicator, which takes care of both physical and biophysical behaviour of the land surface characteristics depending on its land use/land cover (Otterman, 1977, 1980). Considering same atmospheric and solar conditions for the two sets of remote sensing data of same geographical area, the temporal change of albedo can be evaluated and correlated with land degradation through flash flood, change in soil moisture, soil erosion, change in density of vegetation or change in land use pattern. Particularly, in arid and semiarid zone increases in albedo indicate land degradation and decreases may indicate improvement of land. Geomatics 2000: Conference on Geomatics in Electronic Governance, 21-22 January 2000, C-DAC Pune NR33