Impact of canopy scale heterogeneity on modelling the water and energy budget of a rainfed olive orchard

The representation of soil-atmosphere exchanges is fundamental to understand the surface level processes and their interaction with the biosphere. Land surface models (LSM) are continuously improved to better represent these interactions. However, several surface heterogeneity factors such as localized water supply, land covers or various vegetation species make it still challenging to realistically represent the different surface processes. The three dimensional forest model MAESPA and the one dimensional soil-atmosphere-biosphere interaction model ISBA have been applied in order to study the water and energy budgets of the rain-fed olive orchard of Nasrallah in semi-arid area.  Both models have similar approach in terms of soil representation while MAESPA model uses a 3-D individual trees representation and simulation. The aim of this work is to take into account the Nasrallah site heterogeneity factors in order to improve the representation of surface processes. The outcome of this work underlines the contribution of a better consideration of the olive orchard spatial heterogeneity on the surface fluxes simulation. Improvement in water and energy fluxes estimation with more realistic transpiration evaluation have been found compared to field observations with smaller RMSE especially for evapotranspiration by up to 0.2 mm and net radiation flux by up to 7 W/m2.