Climate Modelling Group

Group Leader: Marco Giorgetta

Numerical models are used to express our understanding of the climate system in a computationally accessible form, and as a numerical laboratory to analyze experimentally the effects of modifications of many kinds (model formulation, spatial resolution, choice of initial or boundary conditions). The Climate Modeling Group develops the ECHAM6 model, which is the atmospheric component of the Max Planck Earth system model (MPI-ESM1), and the new ICON atmosphere model, with a research focus on the coupling of physical and dynamical processes. For this the group operates in close collaboration with the developers of other groups and departments at MPI-M, and - in the case of ICON -  institutions, especially the German Weather Service (DWD) and the German Climate Computing Center (DKRZ). Additionally, the group uses the models for research on the dynamics of tropical waves and the wave meanflow interaction associated with the quasi-biennial oscillation.


The ECHAM6 model development is continued since ECHAM6.1 that was used for CMIP5. Several bug fixes in physical parameterizations lead to energy conservation in the total parameterized physics (ECHAM6.2) and a re-calibration of the cloud processes resulted in a "normal" climate sensitivity (ECHAM6.3). These physical improvements are accompanied by technical improvements, as for example the parallel output scheme (ECHAM6.3).


As the development of the ECHAM6 and MPI-ESM1 has progressed, the research focus moves to the ICON model system, in particular to three ICON model configurations: ICON-LES, ICON-CSR and ICON-GCM:

  • The ICON-LES model operates typically at resolutions of 100 to 1000 m, thus resolves large eddies and is suitable to study cloud dynamics. Beside the development and implementation of appropriate process models, as for example a 3-dimensional turbulence model, optimizations of all parts of the model are required for highly parallel execution on 104 to 105 cores. The new ICON-LES model is compared to the established UCLA-LES and PALM models (Opens external link in current windowsee here). In the Opens external link in current windowHD(CP)2 project the ICON-LES model will be employed over a domain covering whole Germany. These developments progress in close collaboration with DWD, the Computational Infrastructure and Model Development group (CIMD) and DKRZ and is partially supported through the HD(CP)2 project.
  • The ICON-CSR model will operate typically at resolutions of 1 to 5 km with the goal to resolve the dynamics and organization of deep tropical convection. Shallow clouds are parameterized. The ICON-CSR model is used in realistic or idealized conditions, where the latter includes the use of double periodic f-planes. This ICON-CSR model will be the application focus of the group for studying the organization of clouds in larger domains and to investigate tropical wave processes in the tropical tropopause region. A similar configuration will be employed in the Tropical Vibes Project for studies in the tropical Atlantic domain.
  • The ICON-GCM will be used typically at resolutions of 10 to 100 km on a global domain, and thus parameterizes all physical processes, as done in ECHAM. Based on this ICON model the MPI-ESM2 will be developed in collaboration with the ocean and land departments and with CIMD.

As this suite of models will span a large range of spatial resolutions and time steps, we will investigate different couplings between the dynamical core, which is the same in all configurations, and the physical processes, which need to be adapted to the cases. This topic will be investigated in collaboration with the Applied Mathematics and Computational Physics group.