Aerosol particles modify atmospheric radiative fluxes and interact with clouds. As documented in the IPCC 2007 report the global influence of natural and anthropogenic aerosols on the atmosphere is not well understood. On regional scale the knowledge is even worse.
Thus, beside observations, numerical models are important tools to improve our current understanding of the role of natural and anthropogenic aerosol particles for the state of the atmosphere. On a global scale there are a large number of model systems and corresponding applications of models addressing the quantification of the effect of anthropogenic aerosol particles on climate change. Due to a lack of computer capacity global climate models however often include simplifications and approximations.
When studying feedback processes between aerosol particles and the atmosphere it is necessary to use online coupled model systems. Here, online coupled means that one identical numerical grid for the atmospheric variables and for the gaseous and particulate matter is used. In addition identical physical parameterisations are used for atmospheric processes such as turbulence and convection. In such a fully online coupled model system all variables are available at the same time step without spatial or temporal interpolation. It allows studying feedback processes between meteorology, emissions and chemical composition. Those online coupled models have to treat the relevant physical, chemical, and aerosol dynamical processes at a comparable level of complexity. Meteorological pre- or postprocessors are not needed.
Studying atmospheric processes with grid sizes down to a few kilometres requires a non-hydrostatic formulation of the model equations on the regional scale where phenomena such as mountain and valley winds, land-sea breezes or lee waves become important.
Therefor the online-coupled model system COSMO-ART was developed, which is based on the operational weather forecast model COSMO (Consortium for Small-scale Modelling) of the German Weather Service (DWD).
Processes such as gas-phase chemistry, aerosol dynamics, and the impact of natural and anthropogenic aerosol particles on the state of the atmosphere are taken into account. As the radiative fluxes are modified based on the currently simulated aerosol distribution a quantification of several feedback processes is possible.
for more details on model description:
or feel free to write an e-mail: bernhard vogel∂kit edu