Post on 27-Mar-2015
Âge (année)
Modèle d'architecture d'arbre:
Atelier de Modélisation de l'Architecture des Plantes, CIRAD- analyse de l'architecture de la plante.- calibration par site à partir de mesures sur le terrain.- simulations -> maquettes (ensemble de cylindres).
Apport:
* Description détaillée des diffuseurs.
* Prise en compte de la variabilité verticale.
AMAP MODEL(Cirad)
• Scatterers density (per layer)• Geometric description• Surface roughness• Moisture (ground, vegetation)• Acquisition parameters (f,p,i)
Inputs ofthe e.m models
Model outputs• backscatter values • scattering mechanisms • contribution of scatterers
EM MODELS(CESBIO)
Interface AMAP/RT(AMAP2SAR)
– Good agreement– Penetration depth seems to be of several meters
Comparison RT-3D modelling and X-band HUTSCAT
measurements
Inversion into foliar biomass (LAI)
Comparison for the 40-year old Austrian pine stand Measured Retrieved Relative
errorTotal LAI
(m2/m2) 5,3 4,8 7,7 %
0
2
4
6
8
10
12
14
16
18
0 0.25 0.5 0.75 1 1.25
LAI (m²/m²)
Hei
gh
t a
bo
ve
the
gro
un
d (
m)
In-situ LAIRadar retrieved LAI
Distorted Born approximation applied to the Distorted Born approximation applied to the modelling of forest scatteringmodelling of forest scattering
Eer
e S Ediffjk r
j
n eff
inc
n
Nn
0
1
Ediff
Einc
exact position of scatterers,
compute S e n Nn
j n , .. 1
horizontal, homogeneous layersto compute(Foldy approximation)
Eeffinc
2D vs 3D modelling for single pass interferometry
Inte
rfero
metr
ic h
eig
ht
Inte
rfero
metr
ic h
eig
ht
Phase centre
2D 3D
X BandSRTM configuration
C BandERS-like configuration
Height retrieval using single pass interferometry: 2D-3D Born approximation modelling
Lozere forest: Corsican pine
Picard G., T. Le Toan, S. Quegan,(2004) « A Three-Dimensional RadiativeTransfer Model applied to ranging scatterometer measurements from a pine forest » Waves in Random Media, 14 (2004), 317-331. Picard G., T. Le Toan, S. Quegan, Y. Cariglio, (2004). Radiative Transfer modeling of cross-polarised backscatter from a pine forest using the discrete ordinate and eigenvalue method », IEEE Transactions on Geoscience and Remote Sensing,Vol 42, no 8, pp1720-1730. Castel T., A. Beaudoin, N. Floury, T. Le Toan, Barczi J.F., and Caraglio Y., "Deriving Forest Parameters for Backscatter Models Using the AMAP Architectural Plant Model", IEEE Transactions on Geoscience and Remote Sensing, 2000. Martinez J.M., N. Floury, T. Le Toan, A. Beaudoin, M.T. Hallikainen, and M. Makynen." Measurements and modelling of vertical backscatter distribution in forest canopy", IEEE Transactions on Geoscience and Remote Sensing, vol. 38, no 2, 710-719, March 2000 Melon P., Martinez JM, T. Le Toan, L. Ulander, A. Beaudoin, "On the retrieving of Forest stem volume from VHF SAR data" , IEEE Transactions on Geoscience and Remote Sensing, November 2001.