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RESEARCH

Staff

Overview

Detailed process models that can be used for sensitivity studies as well as for interpretation of laboratory and field data are necessary to understand multiphase processes. A main objective here is the development of aerosol and cloud modules that combine complex multiphase chemistry with a detailed description of microphysical processes, and their application in three-dimensional atmospheric models. To investigate particle formation in the planetary boundary layer a one-dimensional chemistry-aerosol model has been developed that is based on third-order turbulence closure.

Modeling of Cloud Microphysics. The detailed description of cloud microphysics is realised with a spectral approach. In this way the relevant microphysical processes of the liquid and solid phases can be computed explicitly without the need for parameterizations. A particular focus is on the description of ice nucleation. These processes are investigated with sensitivity studies and simulations of realistic situations.

Modeling of Multiphase Chemical Processes. The simulations of multiphase chemistry processes consider size-resolution and different particle compositions. Droplet activation, phase transitions between gas and particle phases, and a large number of heterogeneous reactions within the droplet and on the particle surface are explicitly described. These computations require consideration of non-ideal solutions. In addition to the liquid phase, the focus is increasingly on the ice phase.

Particle Formation in the Planetary Boundary Layer. A coupled one-dimensional chemistry -aerosol column model of the boundary layer was developed for the interpretation of in-situ observed nucleation bursts, in particular to investigate the role of turbulence. The model is based on third-order turbulence closure. It is used for sensitivity studies and verification of different nucleation mechanisms, making use of field measurements in the planetary boundary layer.