SurfAtm is a model of pollutant exchange between the biosphere and the atmosphere. It is a bi-directional two-layer resistive model for heat and pollutant. This model distinguishes the soil and the plant layers: it describes the exchanges in terms of adsorption to leaf cuticles and bi-directional transport through leaf stomata and soil.
SurfAtm combines a resistive approach for the energy balance and is implemented for ammonia (NH3) ozone (O3) and pesticides. Regarding NH3, it incorporates a compensation point for both stomata and litter or soil, and a cuticular pathway. It has been validated for a grassland. Regarding O3, it includes stomatal, cuticular and soil deposition pathways whatever the canopy development, and is currently validated for maize and wheat. Regarding pesticides, it calculates the pesticide volatilisation just after application, integrating the cuticle penetration and photodegradation of the pesticide.