Modelling of Aerosol Sedimentation

Besides experiments we also conduct modelling studies involving aerosols and their physics. In particular, one current study investigates the role of aerosol sedimentation, i.e. the downward motion and settling on the Earth's surface of aerosol particles due to gravity. The impact of aerosol sedimentation and of its numerical implementation is analysed in the global climate model ECHAM6-HAM. For example, the model currently shows numerical issues in the stratosphere due to the simple numerical scheme used for sedimentation, and far too low aerosol concentrations in the Arctic, presumably because removal processes (including sedimentation) act too strongly during the transport from the mid-latitudes to the Arctic.