Contribution of SAR interferometry (from ERS1/2) in the study of aeolian transport processes : The cases of Niger, Mauritania and Morocco

In order to face desertification and sand encroachment of inter dunes depressions, as well as to protect soils in the area of Gouré (Southeast Niger) where it is possible to have food plantations, it is essential to localize the origin and drift of sands. This paper shows that radar satellite remote sensing and interferometry offers the opportunity to gather all the required information. Digital Elevation Models (DEM) generated by interferometry on ERS 1-2 SAR images (a tandem pair acquired on April 25 and 26 1996) helped to collect information on relief and provided an aeolian
model, while giving some insight into the spatial distribution of sand formations. Interpreting the interferometric coherent image by means of a color composite allowed detecting and locating sand movements in the areas under study. This project mainly highlights the contribution of SAR interferometry in the study of sand movements by developing added-value products. Interpretations were validated using highresolution satellite data (SPOT 5, IKONOS, and QUICKBIRD) and field observations made during a campaign in Niger in March 2004. The same procedure was also applied in Mauritania using two tandem pairs (2–3 November 1995 and 7–8
December 1995) and in Southern Morocco (18–19 May 1996) in order to identify active dunes in these regions. These observations will be taken into account when analyzing ENVISAT-ASAR data.