Mechanistic_modelling_leaf_temperature.Rmd

This R Markdown script presents the mechanistic modelling of leaf temperature.
The script uses BLUP values of six morpho-physiological traits — stomatal conductance (gs), leaf inclination, leaf area, unfolding, reflectance, and transmittance — taken from the file “p279_PechRouge_2024_BLUPs_all_traits.csv", along with mean climatic conditions recorded during the experimental periods, to compute theoretical leaf temperature (Tleaf).
The two first steps involve linearizing the saturated vapour pressure of the air and the longwave radiation term in the energy balance equation using a first-order Taylor expansion around air temperature.
A function is then defined to compute Tleaf using the environmental variables and traits values measured on the panel. This function is applied to all genotypes in the panel to estimate theoretical Tleaf values.
Sensitivity analyses are conducted to evaluate the influence of each trait individually on leaf temperature.
In a second phase, some traits (the unfolding, the incoming radiation, the gaw (and therefore gah) and the transmittance) which weight are too high in the first model, are given increased weighting via empirical coefficients to simulate a leaf temperature closer to the one measured and sensitivity analyses were repeated.