Spectral mixture analysis for monitoring and mapping desertification processes in semi-arid areas

Land degradation due to environmental hazards or man malpracices coupled with successive drought episodes are major problems reducing the capacity of land to produce and regenerate spontaneously in the fragile arid zone of North Kordofan State. Traditional shifting cultivation together with concentration of livestock around perennial sources of water causes excessive utilization of forage plants and alters vegetation composition which ultimately contributes to vegetation and land degradation, sand encroachment and invasion by mobile dunes in the study area. To fill the gap in the technical knowledge with regard to application and adoption of spectral mixture analysis (SMA) and multi-temporal remote sensing data to detect and map desertification processes in semi-arid region of North Kordofan. Three Landsat MSS, TM and ETM+ scenes were selected. Linear mixture model (LMM) and Principle Component Analysis (PCA) were conducted. Eolain Mapping Index (EMI) was also used to map the areas that are frequently subjected to wind erosion hazard. Interpretation of ancillary data and field observations as well as statistical measurements was used to verify the role of human impacts on temporal change of both vegetation cover and sand soil. In this way of thinking, the current study tried to merge remote sensing, climatic and field data to enlighten the nature and consequences of desertification processes in the targeted area. This linkage imposes logical framework to the package of analysis untertaken by author.