F. Mattia et al., An analytical, numerical, and experimental study of backscattering from multiscale soil surfaces, RADIO SCI, 36(1), 2001, pp. 119-135
The objective of this paper is to investigate the backscattering from multi
scale soil surfaces through a comparison of analytical model predictions wi
th numerical computations and experimental data. A numerical simulation of
the backscatter from multiscale surfaces is performed in order to assess th
e sensitivity of the radar backscatter to the multiscale effect as a functi
on of the roughness range of the surfaces, the polarization, and the incide
nce angle of the impinging electromagnetic wave. The numerical backscatteri
ng coefficients are compared with those obtained using the traditional inte
gral equation method (IEM) as well as those obtained using a novel version
of the IEM which has been adapted to model the backscattering from multisca
le surfaces (MLS IEM). As a result, the surface conditions under which the
traditional IEM can still predict well the backscatter from multiscale surf
aces as well as the conditions under which traditional IEM fails are derive
d. Subsequently, 25 m long roughness profiles collected over the Marestaing
test site located near Toulouse, France, are analyzed in order to estimate
input parameters for the two versions of the IEM model. Then, a comparison
is made between the single-scale IEM and MLS IEM predictions and ERS synth
etic aperture radar (SAR) data acquired over the site. The results show tha
t over medium-rough soils (i.e., harrowed soils) the SLS IEM is in good agr
eement (within 1 dB) with ERS SAR data, whereas MLS IEM underestimates the
measurements of 2-3 dB. In contrast, over very smooth soils (i.e., rolled s
oils) the MLS IEM is in overall better agreement with ERS SAR data than SLS
IEM. The latter overestimates the measurements of 3 dB.