Assessing the potential of groundwater resources west of Aswan, Egypt, using ALOS/PALSAR polarimetric information

The hydrological setting of the area west of Aswan city, Egypt that is mainly covered by dry sand is still not well understood, and its groundwater potential remains largely unknown. The ALOS/PALSAR L-band sensor has been used to detect and delineate the subsurface structures along the study area. The circular polarization transformation has been applied on the ALOS/PALSAR full polarimetric data by changing the orientation angle (ψ=0°) and elliptical angle (χ =45°) and revealed many buried faults in various strike directions, which were not reported on the last version of the official geologic map. Such derived circular polarization images were further enhanced by applying the Optimal Polarization Contrast Enhancement (O.P.C.E) method. Thus the proper stocks vectors of the transmitter and receiver have been calculated from the PALSAR full polarimetric data and plotted on the Poincare sphere to determine the best polarization states for imaging these buried faults. The moisture content of the study sites was generally low, with an average of roughly 0.3% during the field campaign. Therefore, the average Root Mean Square Height (Iirms) of the surface roughness was 0.01 cm across all sites. On the other hand, 21 conventional 2D-GPR profiles have been acquired using 270 MHz antenna to validate the radar remote sensing results. These GPR profiles reveal obvious offset in the subsurface stratigraphy.