A MutuallyConsistent Framework for Optical and Microwave Modelling of Scattering from Wheat Canopies

1
A Mutually-Consistent Framework for Optical and
Microwave Modelling of Scattering from Wheat
CanopiesP. Lewis, P. Saich, M. Disney (NERC
CTCD, University College London), T. Macklin, J.
Bodley (BAE Systems), B. Andrieu, C. Fournier
(INRA Environnement et Grandes Cultures), J.
Hillier, J.Watt (University College London)

Model Inversion

• Inversion method dynamic model, invert 2003
  data
• Max. tiller number density
• Thermal time of observation
• Leaf soil scattering properties (moisture etc.)
• For optical, microwave, combined

• Results test against observations
• LAI (1-exp(-LAI/2)
• Max. tiller number density
• Thermal time of observation

Optical
Microwave
Combined
1-exp(-LAI/2)
Thermal Time

• Method summary
• ADEL-wheat not fully tested model
• pragmatic calibrations using ground data (2002)
• Thermal time of observation and tiller number
  density then become main structural driving
  variables
• Relatively small residual effects of plant number
  density
• Despite lack of data for modifications and
  application to different varieties
• Many canopy parameters provide reasonable match
  to simulated
• Not plant height Issues with late planted crop

• Results summary
• Good prediction from forward modelling
• Inversion results of thermal time very good
• and most importantly, consistent between
  datasets
• Inversion of tiller number poor (not shown here)
• large uncertainty in ground observations
• Inversion of LAI
• model over-predicts LAI same as in calibration
• Other parameters
• viable solutions for chlorophyll, water etc. (no
  ground data)

• Future
• Consistent inversion results show power of
  method
• strong constraints on structural description
• potentials for model of water chlorophyll
• Ground trials being undertaken 2004/2005
• test ADEL-wheat for further conditions/varieties
  
• further testing of end-to-end system
• Use model for simulation of data from new
  sensors
• e.g. SPECTRA, TerraSAR

Acknowledgements Pilot project funded by ESA
(Development of Vegetation Architectural Models
for Remote Sensing Applications ESA Contract
14940 ) This study funded by BNSC
(SHIVA-project SAR and Hyperspectral Imaging of
Vegetated Areas) Ongoing work funded by NERC
(Mutually-consistent optical and microwave
modelling)