129 
c 'Robusta ' 
[ i j i ! 
I 
1 LAYER 2 
(f) 
m lay- 
corres- 
subs tantial 
Lar stands 
tory. In L-band 
ickscattering 
f the poplar 
requency. As 
rom the lower 
ience angle, 
i be influenced 
tailed infor- 
)e modified, 
sed and the 
id. 
parameters 
3 , can simpli- 
Lllus trated 
E the cloud 
rough inversion 
Level model. 
Eul tool in the 
if forests. In 
Led for each 
i calculation 
le model is not 
ross errors may 
Figure 10. Simulated radar returns from a poplar 'Robusta' stand based on the multi-level model shown 
as a function of range distance. In sub a and b the returns are compared for the C-band, 16.5 degrees 
incidence angle and an altitude of 323 meters where respectively the level spacing is kept at 9 meter and 
in the second case the level spacing is ignored. In sub c and d the simulation is repeated for an altitude 
of 1800 meter. 
No. 2, pp. 357-364, March-April 1978. 
Attema, E.P.W. and P. Snoeij, 1985, DUTSCAT, 
a 6-frequency airborne scatterometer, Proceedings 
EARSeL Workshop 'Microwave remote sensing applied 
to vegetation', Amsterdam, 10-12 December 1984, 
ESA SP-227, January 1985, pp. 127-129. 
Hoekman, D.H., L. Krul and E.P.W. Attema, 1982, 
A multilayer model for radar backscattering from 
vegetation canopies, Proc.Int.Geoscience and 
Remote Sensing Symp., Munich 1-4 June 1982, 
Vol. 2, TA-1, pp. 4.1-4.7. 
Hoekman, D.H., 1986, Experiments on modelling radar 
backscatter of forest stands and research on 
classification, Proceedings 3-rd International 
Colloquium on Spectral signatures of objects in 
remote sensing, Les Arcs, 16-20 Dec. 1985, ESA 
SP-247, pp. 127-132. 
Ulaby, F.T., R.K. Moore and A.K. Fung, 1982, 
Microwave remote sensing, Vol. II, Reading, MA, 
Addison-Wesley, p. 573. 
the support of 
acial support 
the Netherlands 
Vegetation 
Len.ce, Vol. 13,