signatures of forest radar images at vhf-band. biogeosar07 overview airborne sar system imark...
TRANSCRIPT
BioGeoSAR’07
Overview
Airborne SAR system IMARK
Simultaneous radar and ground-based forest measurements
GPR sensing
Dependencies of backscattered signal on forest parameters
Conclusions
BioGeoSAR’07
Main Features of the IMARK SAR Complex
Parameter Value
Frequency X L P VHF
Wavelength, cm 3.9 23 68 254
Polarization VV, HH, VH, HV
Resolution, m 4-68-10
10-15
15-20
Antennas: gain, dB 3014-17
14-17
9-11
Width in azimuth, deg 18 24 24 40
Width in elevation, deg 24 24 24 60
BioGeoSAR’07
Images Obtained by SAR System IMARK
L-band
P-band
VHF-band
Spas-Klepiki, Ryazanskaya Region
BioGeoSAR’07
The process of boring for the sampling of soil and the appearance of soil samples taken from different depths
BioGeoSAR’07
Use of GPR for carrying out investigations on permittivity fluctuations in subsurface soil layers
BioGeoSAR’07
Theoretical estimation of backscattering from forest stand
1 2 3 4
Typical scattering mechanisms
Scattering from array of cylinderswith height distribution
1
2 0
3 0
24 0
( ; )
; exp 2 cos
; exp 2 cos
; exp 4 cos
trunk
trunk
trunk
trunk
S S
S S R j k h
S S R j k h
S S R j k h
10 15 20 250
0.2
0.4
0.6
0.8
Tree height, m
Bac
scat
teri
ng
inte
nsi
ty, m
-2 HHVV
BioGeoSAR’07
Scattering from layered medium with spatially inhomogeneous dielectric permittivity
Case 1: Layer 2 without large inhomogeneitiesCase 2: Layer 2 with large inhomogeneities(root system)
2
222 """
exp)()(
l
yyxx
l
zzrr
zNNN ff
Three layers: layers 1, 2 are inhomogeneous, layer 3is homogeneous.Correlation function of dielectric permittivity:
BioGeoSAR’07
Experimental dependencies of backscattered signal on stem diameter and distance between trees
0
5
10
15
20
0,10 0,15 0,20 0,25 0,30 0,35
diameter of tree steem, m
stre
ng
th o
f si
gn
al, r
elat
ive
mag
nit
ud
e
12
3 45
6
0
5
10
15
20
1.00 2.00 3.00 4.00 5.00 6.00 7.00
distance between trees, m
stre
ngth
of s
igna
l, re
lati
ve m
agni
tude
12
34
5
6
BioGeoSAR’07
0
5
10
15
20
12.00 14.00 16.00 18.00 20.00 22.00
height of trees, m
str
en
gth
of
sig
na
l, re
lati
ve
ma
gn
itu
de
12
3
45
6
0
5
10
15
20
200 250 300 350 400 450 500 550 600 650
biomass, m3/hа
stre
ng
th o
f si
gn
al, r
elat
ive
mag
nit
ud
e
1
2
3
4
5
6Experimental dependencies of backscattered signal on tree height and biomass
BioGeoSAR’07
Conclusions
Backscatter from forest at VHF band at HH polarization increases with the growth of biomass and tree diameter
Measurements conducted by ground penetrating radar confirm spatial variation of dielectric constant of the upper subsurface soil layer of forest
Large fluctuations of dielectric permittivity of the upper soil layer related with the presence of tree root system have significant importance in the formation of backscatter from forestland
Measurements conducted in different periods of time indicate the seasonal variation of backscatter from coniferous forest