Vegetation Radiative Transfer Modelling (Nadine Gobron) - PEER

Extinction coefficient
We now consider photons at a depth z traveling in direction Ω.
The extinction coefficient is then the probability, per unit path length,
that the photon hits a leaf, i.e., the probability that a photon while
traveling a distance ds along Ω is intercepted by a leaf divided by the
distance ds.
e
( z, ) G( z,
) ( z)
σ Ω = Ω λ
Where the geometry factor G is the fraction of the total leaf area (per
unit volume of the canopy) that is perpendicular to Ω
1
G ( z,
) = ( Ω ) | Ω • Ω |
l l
2π
2π
Ω ∫ g
d
l
Ω
l
Ross J. (1981) ‘The Radiation Regime and Architecture of Plant Stands’, The Hague-Boston-London: Dr. W.Junk
Publishers, 391 pp.
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