National CMIP6 Support Activities

As during the 5th phase of the International Coupled Model Intercomparison Project (CMIP5), the German Federal Ministry of Education and Research (BMBF) also supported the German climate research in the 6th phase in the generation of the national contribution to the data base for the next assessment report (AR) of the International Panel for Climate Change (IPCC). The funding covered four and a half years and ended in December 2020. A concise overview over the CMIP6 related activities and model simulations at the DKRZ can be found here.

The main objectives in the project are the provision of the German contribution to the data base for the IPCC/AR6, competence building for compliant data processing in accordance with the CMIP data standards for the national CMIP6 participants and the fulfillment of the conditions laid down by the CMIP6 Panel for participation in the model intercomparison projects (MIPs) endorsed by CMIP6. In addition to the publication of the data in a CMIP-ESGF data node, this also includes carrying out the so-named DECK experiments, which form the persistent nucleus of the CMIP experiments. The DECK experiments include the preindustrial control experiment under constant conditions (piControl), another experiment under constant conditions but with an increase of 1% per year of atmospheric CO₂ (1pctCO2), and 3 third experiment under constant conditions but with a CO₂ concentration increased by a factor of four compared with that of piControl (abrupt4xCO2), as well as an experiment in which the sea surface temperatures and sea ice extent are given according to the AMIP observation data (amip). No DECK experiment, but also a condition for participation in CMIP6, is the execution of a historical hindcast experiment which is intended to reproduce the historical climate from 1850 to the present (2014) using the observational external input data provided by CMIP6. For a description of the CMIP6 project design see Eyring et al.(2016).

Organizationally, the activities are divided into 2 alliances. Alliance-1 (DICAD) supports national modeling groups both in the production of quality-assured standard-compliant CMIP6 data, as well as in the publication of the model results on the ESGF data nodes of the DKRZ, and the execution of the DECK experiments. In addition, national research is supported by replication of data from other ESGF data nodes and the implementation of a diagnostic tool for timely model validation and model comparison (ESMValTool) as well as an access portal to the ESMValTool results.
In addition to the above five experiments, the new CMIP6 scenarios will be used to provide results of new climate change experiments as definded by the ScenarioMIP, one of the Model Intercomparison Projects endorsed by CMIP6 (CMIP6 endorsed MIPs). The projections will be based on the climate model MPI-ESM-1-2-HR,  a high - resolution and furher developed version of MPI-ESM, that has already participated in CMIP5. These calculations are considered a national task. Scenario experiments will be performed with the other models in the project later on, depending on their progress in the project.

Alliance-2 (Chemistry) focuses on atmospheric chemistry and supports the national research community through model development so that participation in the chemistry project endorsed by CMIP6 (AerchemMIP) becomes possible.
Fullfilment of the participation conditions, i.e. performance of the DECK and CMIP6 experiments (piControl, AMIP, historical, 1pctCO2, and abrupt4xCO2) with atmospheric chemistry models also is within the scope of Alliance-2.