Monitoring Land Degradation in Drylands by Remote Sensing

Abstract

This article aims at introducing the application of remote sensing techniques to monitoring land degradation and desertification in arid regions based on a review on actually available methods and several pertinent case studies. It is considered that land degradation, a process of reduction in vegetation cover and water resource, soil erosion and of salinization, etc., is a subtle and progressive environmental change in time. It is therefore necessary to conduct multi-temporal or even time-series observation. Coarse resolution data can be used to reveal regional, continental and even global level environmental changes and target the “hotspots”. However it leaves many uncertainties. On the contrary, high and very high spatial resolution data are capable for highlighting such a subtle change in detail at local level. To avoid badinterpretation, meteorological data should be combined in analyses to make sure that the differences in spectral reflectance observed are representing true changes but not climate related events like droughts. Furthermore, it is essential to link remote sensing with human activity to understand the mechanism of land degradation and its driving forces. In this way, remote sensing will be not only a powerful tool for providing dynamic information to monitor land surface changes and degradation on different scales but also for helping decision-making in producing relevant mitigation measures for sustainable resource exploitation.