
TY  - JOUR
A1  - Wang, Ying Ping 
T1  - A comparison of three different canopy radiation models commonly used in plant modelling
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 2003
VL  - 30
IS  - 2
SP  - 143
EP  - 152
KW  - radiation model, photosynthesis, Beer&#39;s law, two-stream approximation, canopy, latent, sensible heat, albedo.
UR  - https://doi.org/10.1071/FP02117 
N2  - Three radiation models are compared. They are the two-stream approximation, Goudriaan&#39;s radiation model and Beer&#39;s law. If direct beam and diffuse radiation are considered separately with the appropriate extinction coefficients, Beer&#39;s law can be used to estimate the fraction of absorbed visible radiation quite accurately, as compared with the other two models. However, Beer&#39;s law always overestimates the fraction of absorbed near-infrared radiation because of the significant loss of scattered radiation in the near-infrared radiation waveband; the error can be up to 50%, compared with the two-stream approximation. The error is systematic and is not reduced by integrating over a day or longer. It can be even larger if absorption of direct beam and diffuse radiation are not considered separately. Compared with the two-stream approximation, Goudriaan&#39;s model underestimates the amount of absorbed visible and near-infrared radiation, and consequently net photosynthesis, and overestimates sensible heat fluxes of the canopy when Goudriaan&#39;s model is used to estimate the amount of radiation absorbed by sunlit and shaded leaves within a canopy in the CSIRO Biosphere Model. However, the mean differences in the calculated hourly fluxes of net canopy photosynthesis, latent and sensible heat are less than 5% for a wheat crop during the whole growing season. 
ER  -

