Earth System Modeling and Predictions

A global decadal climate prediction system has been developed by the predecessor of our group (“decadal climate prediction — MiKlip”, Marotzke et al, 2016, Hettrich et al 2021), which is now the basis for routinely produced forecasts. Further scientific research and development, however, is required to achieve and enhance a competitive next generation of global prediction system, which naturally will be based on the state-of-the-art ICON environment. This research to operation is currently shared by a consortium of DWD, Universität Hamburg and our institute, complemented with further research on regional modeling and prediction (Karlsruhe Institute of Technology) and post-processing (Freie Universität Berlin). In our group, we provide the modeling basis for such a prediction system tailored with process studies enhancing the climate predictability. Exemplary are lsingle forcing large ensemble experiments to assess the role of forcing components for decadal variability and prediction, or the assessment of the role of the North Atlantic ocean inertia for skill assessment over Europe.

The observed European summer temperatures have increased by ~1.5–2 °C since the 1990s and are expected to increase further due to the global mean temperature rise. The internal variability (ranging from years to decades) of European summer temperatures, however, is large in comparison to the observed temperature rise.  It offers an opportunity for climate predictions, the attribution of extreme events and the distinguishably of their likelihood of occurrence within limit targets set by the UNFCCC Paris Agreement (Suarez-Gutierrez et al., 2018). By using large ensembles of MPI-M Earth System models, we examine the well-sampled internal variability of European summer temperatures and associated extremes (Suarez-Gutierrez et al., 2020). We further specify the sources of the variability of European summer temperatures on sub-decadal to multi-decadal time-scales and their probable prediction skill in the decadal prediction system (Ghosh et al., 2016, Borchert et al., 2019, Müller et al., 2020). The examinations of the well-sampled internal variability of temperatures and associated extremes, and its decomposition into decadal time-scales, provide significant steps towards the understanding of the full bandwidth of appearances of European summers.