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Scientific
projects
Current projects
 the
SMOS programme (CESBIO, CNRM, ONERA)
Characterization
Campaign of Reference Thermo-regulated Patterns
Previous projects
field measurement of bidirectional spectral
reflectance in the 0.4 - 2.5 µm spectral domain (ONERA)
infrared
radiometry in the 3-5 µm spectral band (ONERA, LSIIT)
project
for analysing directional effects in the thermal infrared range
(8-14µm) for heterogeneous scenes (ONERA, CESBIO)
 fraction
of PAR intercepted by a vegetal cover (CESBIO)
| Fraction of PAR intercepted
by a vegetal cover: impact of the spatial heterogeneity and
sky conditions |
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Participating laboratories: CESBIO.
Objectives: (i)
test a model currently used by scientific community which simulate
the incident solar radiation composition from empirical relations;
(ii) evaluate the importance of the spatial heterogenity
and the composition of incident radiation in the fIPAR simulation
using different models (for instance, a simple semi-empirical model
using an agregation coefficient to take spatial heterogeneity into
account, and a more complex model using a 3D detailed description
of canopy structure).
Means: a 10x10m parcel of
fallow land (ashes) presenting a real spatial heterogeneity is instrumented
with 33 PAR/LE (Solems) within the tree cover, BF2 Sunshine Sensor
(Delta-T), CNR1 Net radiometer (Kipp&Zonnen), 2 CM11 Pyranometer
(K&Z) and CM 121B Shadowring (K&Z), in order to measure:
- the global and diffuse incident radiation
in the visible/NIR band (300-2800 nm) and for PAR wavelengths
(400-700 nm), the transmitted and reflected PAR, the fraction
of PAR intercepted (fIPAR) by the canopy; these measurements are
taken every 5 minutes;
- the leaf area index (LI-Cor, LAI-2000); measurements taken every
two weeks during leaf expansion, and every week at maximum LAI;
- allometric measurement: total height, trunk height, trunk diameter,
DBH.
Pictures of installations
Contacts: Valerie.Demarez@cesbion.cnes.fr,
Sylvie.Duthoit@cesbio.cnes.fr.
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