Contribution of low frequency radar imagery to hydrogeological exploration in arid countries.
The potential of radar imagery in hydrogeological exploration was investigated at a study site in Egypt (Bir Safsaf) and in Mauritania (Akjoujt region). Compared with optical images, the results obtained show how radar imagery can help not only in detecting surface geological structures such as dykes and veins, but also mapping subsurface structures beneath a shallow layer of sand, i.e., palaeochannels. The mapping potential was found to be much better at long wavelengths than at short ones (L-band, compared with C- and X-band). As for optical images, their contribution is much more limited in the mapping of surface hydrogeological structures, and inappropriate for detecting subsurface structures. We conclude that radar remote sensing enables the improvement of existing geological and hydrogeological maps and the optimization of cartographic surveying; these works being the preliminary steps of water prospecting projects in arid countries.
> GrandjeanG., Paillou Ph., Baghdadi N., Heggy E., August T. , and Lasne Y., 2006. Surface and subsurface structures mapping using low frequency radar. A synthesis of the Mauritania and Egyptian experments.. Journal of African Earth Sciences (JAES), vol. 44, pp. 220-228.
> Baghdadi, N. GrandjeanG., LahondereD., Paillou P., and Lasne Y., (2005). Apport de l'imagerie satellitaire radar pour l'exploration géologique en zones arides. C. R. Acad. Sci. Geoscience 33, 719-728
> Lasne, Y., Paillou, P., August-Bernex, T., Ruffié, G., and GrandjeanG. 2004. A phase signature for detecting subsurface wet structure using polarimetric L-band SAR. IEEE Trans. Geosci. Remote Sensing, TGARS, 42, 8, 1683-1694.
HyMeX – Hydrological cycle in the Mediterranean Experiment 2010-2020