During the summer of 1988 an intensive field experiment was conducted in the vicinity of Pisgah lava field in the Mojave Desert of southern California. As part of the experiment, physical properties such as microtopography, composition, soil moisture and dielectric constant at five different sites representing surfaces with r.m.s. heights varying from less than one centimeter to tens of centimeters, were measured. In addition, polarimetric radar images at P-band (68 cm wavelength), L-band (24 cm) and C-band (5.7 cm) were acquired at three different incidence angles with the NASA/JPL airborne imaging radar polarimeter. Using trihedral corner reflectors deployed in the prior area to imaging, the radar images were calibrated to provide &sgr;0 values for each resolution element in each scene. This paper reports on the derivation of the power specturm of surface microtopography by solution of the small perturbation model for multiple incidence angle and multiple frequency radar data.

Power-law fits to the power spectra have exponents (slope in log-log plots) that are nearly the same for all surfaces. These values are close to those from measured microtopography profiles. The offset in log-log plots shows very good correlation with measured power spectrum offsets, however, the derived offsets are consistently lower than measured values. This may bet the result of calibration errors, using the wrong dielectric constants in the inversion, or the fact that not all observed energy was scattered by the surface interface alone.