E. Mougin et al., EFFECT OF TREE STRUCTURE ON X-BAND MICROWAVE SIGNATURE OF CONIFERS, IEEE transactions on geoscience and remote sensing, 31(3), 1993, pp. 655-667
Experimental studies are performed on some coniferous trees: Austrian
pine, Nordmann spruce, and Norway spruce, to investigate the relation
between the tree architecture and radar signal at X-band. For a single
tree, the RCS is measured as a function of the scatterer location at
90-degrees incidence. It is found that the main scatterers are the lea
fy branches and the difference between sigma(vv) and sigma(hh) is sign
ificant at the upper portion of the tree. At the lower portion of the
tree sigma(vv)o and sigma(hh)o have almost the same level. For a group
of trees the angular trends of sigma(vv)o and sigma(hh)o are measured
. It is found that the levels of sigma(vv)o and sigma(hh)o are of the
same order, but their angular trends vary from one tree species to the
other depending on the tree species structure. The interpretation of
these experimental results is carried out with the help of a theoretic
al model which accounts for the structure of the tree. According to th
is theoretical study, the major scattering trend is due to the leaves,
while the perturbation to the angular trend and the level difference
between sigma(vv)o and sigma(hh)o are due to the branch orientation di
stributions, e.g., the tree architecture.