Environmental Modelling in the climate system


Prof. Dr. Holger Tost


Research fields:

Our working group deals with interactions of chemical and physical processes in our Earth System on different temporal and spatial scales. For these studies we develop comprehensive models with a focus on atmospheric research, and conduct simulations to provide answers for current topics on environmental and climate problems.
We investigate in detail the role of clouds and convection in the atmosphere. A focus in this research is the question how clouds affect atmospheric chemistry, but also how clouds are affected by multiphase chemical processes. A central point is the role of aerosol particles (and their chemical composition) for cloud formation and cloud properties.
A further key aspect are effects of atmospheric chemistry on the dynamics of the atmosphere and the global climate of the Earth System.

Main tool for our research is the Modular Earth Submodel System (MESSy), which is linked with the global climate model ECHAM5 and the weather forecast model COSMO. We are including additional components and processes in the Earth System to conduct holistic simulations for climate and environmental research.

The animation from a global simulations shows the impact of lightning on upper tropospheric aerosol nitrate with the isosurfaces depicting up to 60% relative differences compared to a simulation without emissions of NOx from lightning.

Ongoing projects

  • (Super-)Parameterised convection for large-scale models (Rybka, Tost)
  • Multiphase chemistry in aerosols and clouds (Tost)
  • Aerosol-Cloud Climate interactions (Tost)
  • Biological aerosol particles (Barthelmehs, Tost)
  • Climate and atmospheric mixing of the early Earth (Schneider, Tost)
  • Predictibility of climate on the meso-scale (Pankatz, Kerkweg)
  • Two way nesting in regional and global modelling (Hofmann, Kerkweg)
  • Atmospheric dust aerosol (Tost)
  • Impact of vegetation in Earth System Modelling (Tost)
  • Turbulence in large scale models (Kaiser, Tost)
  • Regional aerosol pollution in the Rhein-Main area (Barra, Tost)


Finished projects

  • Parameterised lightning for large-scale models (Bittermann, Tost)
  • Precipitation quality (Schreiber, Tost)
  • Aerosol scavenging by solid hydrometeors (Lüttmer, Tost)
  • Aerosol-Photolysis interactions (Klinkert, Tost)
  • The global HCN budget (Fleger, Tost)