The Scavenging submodel simulates the processes of wet deposition and liquid phase chemistry.
It is suitable for gas-phase as well as for aerosol species and occurs in convective and large-scale precipitation. The aerosol species are removed from the atmosphere by impaction scavenging in the precipitation flux and nucleation scavenging in clouds during precipitation formation. The budgets of gaseous species are calculated in a more or less comprehensive mechanism of differential equations that treats transition into and out of droplets, dissociation of acidic and alkaline species and liquid phase redox reactions. It is easy expandable or reducable respectively to the needs and amount of used tracers. The whole system of differential equations is solved via KPP (kinetic preprocessor version 2) which uses a 3rd order Rosenbrock solver.
As the uptake of the species into the droplets is dependent on the gas-phase concentration and the solved species in the precipitation flux the whole system is two-way coupled.
More information can be given on demand......
A publication of the technical details of the SCAV submodel can be found at the ACP page of this paper. The submodel is continuously updated both in terms of considered processes (e.g., the ice phase) as well as aqueous phase reaction rates.
A general overview is given in the sketch below.