Assessing Spatio-Temporal Sand Dune Changes Within the Sahara of Algeria Using Landsat Satellite Data

Abstract

Desertification is one of the environmental problems which is perplexing many regions in the world. Three Landsat images,acquired in 1987,2001 and 2006, were analyzed to evaluate sand desertification processes in Algerian Sahara. Multitemporal comparison techniques were applied to estimate the sand desertification and to emphasize land cover variation over time and in space. Spectral Mixture Analysis (SMA) was using endmembers spectra derived from the images. Area-specific interactions between human activity, climate variation,and natural processes played a role in sand desertification,however, their interaction varied according to the ecological zone.The main objective of this study is to identify regions of change in the multi-temporal sand dune.The degradation moreover promoted sand encroachment and dune migration.In a different way, climatic constrains drove sand desertification. Drought, degradation and soil erosions were the causes and effects of sand desertification.In this site, re-growth conditions were observed only where forestry or agricultural projects were established. Area strategies, which take into account the interactions of the driving factors at the local scale,are thus necessary to combat desertification, avoiding any implementation of untargeted measures.