Contribution of SAR Interferometry (from ERS1/2) in the Study of the Eolian Transport Processes: Cases of Niger, Mauritania and Morocco

Catherine Bodart(1) , André Ozer(1) , and Jean Gassani(1)

(1) University of Liège, Allée du 6 août, 2 - B11 , B-4000 Liège, Belgium

Abstract

In order to face desertification and sand cover of the interdunar depressions as also to manage these sole parcels were food crops are possible in the area of Gouré (Southeast Niger), it is mandatory to localize the sands’orign and the sands’drift. In this paper, we show that Satellite Remote Sensing gives us the opportunity to gather all the required information. Coupling hight resolution satellite data (SPOT 5) and Digital Elevation Model generated by interferometry on a ERS 1-2 SAR images (a tandem pair acquired on april 25th and 26th 1996), provides us relief information, an eolian model and the spatial arrangement of sand formations. Interpretation of the interferometric coherent image, by means of a composite colour, allowed to detect and locate light sand movements in the area under concern.

This project mainly highlighted the contribution of SAR interferometry, through the development of added value products, in the study of sand movements.

Same procedure was also applied in Mauritania using two tandem pairs (2-3th november 1995 and 7-8th december 1995) and South Morocco (18-19th may 1996) in order to identify active dunes in these regions. All interpretations were checked on the field during a campaign in Niger during March 2004 and with other Remote Sensing data. These observations will be taken into account while ENVISAT-ASAR data will be analysed.

This study was supported by the ESA ENVISAT program: Project FADA (Fight Against Desertification in West Africa), by ISIS for the SPOT images and by CUD (Coopération Universitaire pour le Développement, Belgium) for the field trip.

All the InSAR processing, including georeferencement were performed using the "Centre Spatial de Liège" InSAR/DInSAR processor. We thank Dr. Dominique Derauw for helpfull discussions.

 

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