Modelling solar radiative transfer inside the oasis - Experimental validation

A semi-empirical model of solar radiation intercepted in an oasis canopy was developed. We have been able to determine the sharing of radiation between the three croplevels and to estimate the mean solar radiation that penetrates inside the vegetation from above-canopy measurements only. In our model we distinguish between direct solar radiation, diffuse solar radiation and scattered radiatives fluxes (upward and downward). The calculus needs the measurements of the leaf area index and leaves transmittance and reflectance, so we have measured them. For validating our model, we have compared the modelled values to the experimental data. We can signal a good behaviour of the model. While, due to the fixed position of the sensors and the poor documentation about the detailed geometrical structure of the trees inside the oasis, we notice some difference between measurement and calculus especially for the market gardening. (C) 1999 Elsevier Science Ltd. All rights reserved.