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 recently culminated in the development of the MPI Earth system model, the MPI-ESM. 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 the sometimes unorthodox use of our most complex models. And although our Earth System Model, is 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.


The MPI-ESM (The MPI-M Earth System Model)

The MPI-ESM is a comprehensive Earth-System Model, in the sense that it couples the ocean, atmosphere and land surface through the exchange of energy, momentum, water and important trace gases such as carbon dioxide. As such it reflects the interests and expertise of the three departments that constitute the MPI-M. The MPI-ESM was used as the basis for our contribution to the fifth phase of the coupled model intercomparison project (CMIP5), and is the current workhorse of institute scientists. It is the successor the the previous ECHAM5/MPIOM coupled model, which was used for the CMIP3 project, and for the internal Millenium project. The development of the MPI-ESM is coordinated by the Coupled Model Steering Group.



ICON is a new, non-hdyrostatic, icosahedron-based, dynamical core, developed using finite volume discretization techniques. It is being developed jointly with the German Weather Service for use as the basis for the MPI-ESM2. ICON will allow Earth System Modelling within the institute to better exploit very high performance computing architectures, and provide a basis for exchanging ideas with colleagues working on related problems in numerical weather prediction. More information about the ICON project, and access to the ICON code, is provided on the ICON webpage.



Component Models

The component models used in our coupled, or Earth System Model, are also distributed individually. These are ECHAM6, which is an atmospheric general circulation model that also includes an advanced treatment of the terrestrial biosphere using the JSBACH model, and the MPIOM, which is an ocean general circulation model which represents marine biogeochemical processes using the HAMMOC model.

Process Models

Scientists at the institute also make use of a variety of process models.  In particular atmospheric phenomena, and land atmosphere interacts, are studied in more idealized settings using large-eddy simulation.  The institute has an unusual concentration of these models, as three of the five or six world-wide leading large-eddy simulation models have been developed and/or maintained by institute members.  The institute also is one of the only institutes worldwide to maintain the capacity to perform direct numerical simulation of multiphase flows in the atmosphere and ocean.