Regional ocean Zooms for Extremes and impacts at Global and local scales (RaZorEGe) will develop and implement Earth System Models (ESMs) capable of robustly representing regional aspects of climate while remaining affordable for efficient global multi-centennial simulation. Projections of regional climate variability, change and extremes remain challenging to simulate with ESMs for a variety of reasons, including local process representation, errors in remote teleconnections and the inherently greater variability of regional climate requiring larger ensembles. For Europe, the representation of the Gulf Stream, the Atlantic Meridional Overturning Circulation and the Mediterranean are all key uncertainties for future change, while other ocean boundary currents (the Kuroshio in the Pacific and the Antarctic Circumpolar Current in the Southern Ocean) are key for East Asian and South Africa respectively.
We propose to achieve this improvement through targeted developments in ocean and sea-ice models, based on understanding the relationships between regional climate indices and ocean/sea-ice model biases. We will use a range of techniques, including regional changes in horizontal and vertical resolution, as well as new parameterisations. One key aspect of the targeted nature of the developments will be to keep the model efficient enough to be affordable with Earth System complexity included, hence trying to bring together improved physical and biogeochemical processes.
Once demonstrated, these enhancements will be implemented in ESMs and simulations performed that will contribute to the next Coupled Model Intercomparison Project (CMIP7) and next IPCC. The limited cost increase, and targeted process improvements will mean that these enhancements should also be applicable to other modelling systems, such as seasonal-to-decadal prediction and Destination Earth, hence strengthening collaboration across these areas.
48 months from 01/01/2027 to 31/12/2030
General aims
O1: Improve reliability of the evolution of regional climate by understanding its relationship with ocean and sea-ice model biases and applying this knowledge to targeted model enhancements.
O2: Develop and apply a toolkit to improve ESM simulation while minimising increases in model costs. Such tools should also be applicable to other initiatives, such as seasonal-to-decadal prediction systems, Destination Earth (DestinE, Hoffman et al., 2023), CMIP7 and others.
O3: Improve robustness of predictions and projections of the global Earth System, and impactful regional extreme events such as marine and terrestrial heatwaves, heavy precipitation events, droughts and storms for the next decades.
O4: Produce simulations to contribute to long term FAIR (Findability, Accessibility, Interoperability, and Reuse) archives such as CMIP7 and which contribute to Intergovernmental Panel on Climate Change (IPCC) Assessment Report (AR7) and beyond.
O5. Sustain and enhance European cooperation and leadership in climate sciences.
CMCC role
CMCC is leader of WP1 and WP2. Participant in the other WPs. CMCC brings expertise on standalone and fully coupled general circulation models as from the long experience on CMIP effort.
Activities
– Use existing model simulations, observations and reanalyses to discover links between evolution of regional climate and ocean-sea-ice biases, both local and via remote teleconnections; derive metrics to measure.
– Develop and refine tools for addressing ocean-sea-ice model biases prioritised by regional metrics from O1; implement new methodologies and technologies in Razorege models and assess for both their scientific and computational performance.
– Production of Razorege ESM simulations and their assessment using standard and newly developed diagnostic tools; use observations and reanalyses to assess models in historical period.
– Produce climate simulations using both ocean-sea-ice and coupled ESMs; aim to optimally increase the (heterogeneous and homogeneous) ensemble size as compared to PRIMAVERA/EERIE; process and archive these in standard repositories and make them available to the international community.
– Build on previous projects, particularly PRIMAVERA and EERIE; play a leading role in CMIP7, via OMIP, HighResMIP and DCPP contributions, and contribute to the next IPCC; expand international collaborations; transparency and openness; engage and inform the public.
Expected results
– Advanced understanding and capability to predict the future evolution of the Earth system, at global to local spatial scales and from weather to climate timescales, including the socio-economic and environmental impacts of these changes
– Advanced understanding and capability to predict regional climate variability, including extreme events and regional water cycle, in particular, regional precipitation.
– Strengthened collaboration and cross- fertilization across available approaches to Earth system and climate modeling science, enabling a joint contribution to the next generation of Earth system models (ESMs)
– Long-term science, modeling and evidence base to support European and international policies are advanced.
Partners
NCAS-Climate, University of Reading (UREAD)
University of Bergen (UiB)
STIFTELSEN NANSEN SENTER FOR MILJOOGFJERNMALING (NERSC)
National Centre for Scientific Research (CNRS)
GEOMAR Helmholtz Centre for Ocean Research Kiel (GEOMAR)
Institut Français de Recherche pour l’Exploitation de la Mer (Ifremer)
Met Éireann (ME)
Pusan National University (PNU)
University of Cape Town (UCT)
Fudan University (Fudan) (Associate Partner)
Academia Sinica (AS) (Associate Partner)