ICON Configurations

At the MPI-M efforts to understand Earth's changing climate are focused around the innovative use and development of comprehensive Earth system modeling. In so doing we build on the history of research within our institute, which started from the development of component models of the atmosphere and ocean, moved to pioneering studies of the coupled atmosphere-ocean system, and culminated in the development of the MPI-M Earth system models. However, increasing further the complexity of our models will not by itself provide answers to our guiding questions; instead, answers will arise from the richness and clarity of the concepts that our models help us create. For these purposes idealized modelling, designed to distill an idea or theory to its essence, plays an increasingly important role in our research, and guides sometimes unorthodox use of our most complex models. And although our Earth system models are in the focus of most of our development effort, the flexibility provided through the development and use of component models, designed to represent a subset of Earth system processes with increased fidelity, is also important.

Jointly with the German Meteorological Service (DWD), the German Climate Computing Centre (DKRZ) and the Karlsruhe Institute of Technology (KIT), the Max Planck Institute for Meteorology develops the ICON modelling framework for a broad range of applications. Within this framework, MPI-M develops and maintains the ICON Earth system model (ICON-ESM - Ruby) and the large eddy resolving model (ICON-LEM - Sapphire). Different configurations are used in the context of MPI-Ms experimental strategy.


ICON-ESM (Ruby) is the most recent Earth system model of the Max Planck Institute for Meteorology, based on the ICON component models ICON-A for the atmosphere, ICON-L for the land and ICON-O for the ocean. ICON-Ruby includes the physical processes and biogeochemical extension for the carbon cycle. ICON allows Earth system modelling within the institute to better exploit very high-performance computing architectures, and provides a basis for exchanging ideas with colleagues working on related problems in numerical weather prediction.

This model configuration is used mostly in the context of our Ruby experiments.

ICON-Sapphire (ICON-LEM)

ICON-LEM (Sapphire) is the ICON configuration for large eddy simulations. ICON-LEM combines the dynamical core with a minimal set of parameterized processes compared to the strongly parameterized global ICON-A model. Practically ICON-LEM is used as a regional model for idealized or realistic boundary conditions.

ICON-LEM has been used successfully in the HD(CP)2 project for simulations at a resolution down to 150 m over a domain covering Germany.

Today, this model configuration is used mostly in the context of our Sapphire experiments.

ICON-A (Atmosphere)

Also used for bleeding edge high resolution (HR) simulations of high scientific value, but naturally extensively for experiment preparation and testing.


JSBACH is the land component of the MPI Earth System Models MPI-ESM and ICON-ESM. As integral part of the respective atmospheric component (ECHAM, ICON-A), it provides the lower atmospheric boundary conditions over land. In addition, it adds the biogeochemical and biogeophysical degrees of freedom to the Earth system dynamics that arise from terrestrial processes. JSBACH can be run online, i.e. as part of its atmospheric host model ECHAM6 or ICON-A, or offline ("JSBALONE") forced by climate data.

ICON-O (Ocean)

ICON-O is the ocean model based on the ICON framework. It provides the ocean component of the ICON-ESM <link>, but can also be used in stand-alone mode forced by atmospheric data from climatology (OMIP) or reanalyzes. ICON-O includes a sea-ice model and the HAMOCC ocean biogeochemistry module. The unstructured nature of the grid enables a large variety of set-ups to be realized ranging from approximately uniform global resolution to strongly focusing grids.

The precursor of ICON, the traditional Max Planck Institute Earth System Model (MPI-ESM), which consists of the component models ECHAM6 for the atmosphere, MPIOM for the ocean and JSBACH for the land. It was MPI-M’s model „workhorse“, also for many external projects. Internal use stopped. MPI-M still provides access to versions of the MPI-ESM.