干旱区生态环境知识资源中心

Desertification is one of the most important problems driven by global climatic change. There are many factors that contribute to the environmental degradation of the Sahara desert surroundings. The first one is related to human activities, such as change of land use. Other factors include natural degradation due to change in temperature, humidity, and wind. All of these complex causes may lead to the movement of sand from the desert to other places, such as cities and roads, affecting everyday life. For that reason, desertification is being analyzed by governmental agencies in the affected countries. This paper studies this phenomenon in the city of Biskra, Algeria, using optical satellite images taken from the freely available Landsat program. It presents a methodology that could help in the temporal evaluation of the desertification process. Land use and land cover change detection in a period of 25 years has been carried out using a support vector machine per object classification. Change indices have been also employed for assessing the degradation. Excellent results using low human operator cost have been fully validated by visual inspection.