抄録
The AIRSAR system simultaneously records microwave data in P-band (68cm), L-band (24cm) and C-band (5.6cm), and measures the complete scattering matrix for each ground cell, thereby allowing the calculation of all polarizations for each frequency. This study aims at exploiting the ability of AIRSAR data to provide information about the terrain for mineral exploration, which is otherwise unobtainable from optical remotely sensed and other geophysical datasets. Two study areas were selected from South Australia for this purpose;Tarcoola, poorly outcropping granite terrain with high potential for Au and base metal mineralisation;Hilga, covered by a thin layer of aeolian sand within the sandplains and dunefields of the Great Victoria Desert, for assessment of the penetration capability of the longer-wavelength microwave.
The radar backscatter from the earth's surface at a given wavelength and polarization is primarily a function of surface roughness and dielectric constant. To provide an understanding of the relative contributions of these parameters, and to enable unmixing of their effects in the AIRSAR data, field measurements of soil moisture, dielectric constant and surface roughness were made at selected ground sites across the Tarcoola area. Rock chip samples collected during the field survey were tested for their dielectric properties in the frequency ranging from 100 MHz to 3GHz. The results agreed with digital analysis of polarimetric AIRSAR data. GPR (Ground Penetrating Radar) was employed to assess the penetration capability of the longerwavelength microwave for subsurface geological mapping. GPR profiles showed the penetration of several tens of centimeters.
