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.