GCM Selection and Ensemble Design: Best Practices and Recommendations from the EURO-CORDEX Community

Abstract High-resolution climate information is critical for the Vulnerability, Impacts, Adaptation, and Climate Services (VIACS) communities. Coordinated ensembles generated by initiatives like the Coordinated Regional Climate Downscaling Experiment (CORDEX) provide consistent and comparable information for the present and future over all land areas of the globe. This manuscript focuses on the European CORDEX initiative (EURO-CORDEX) and its coordinated effort to build regional climate ensembles for the years to come. In its first phase, EURO-CORDEX produced a rich ensemble of regional climate simulations under different representative concentration pathway scenarios. The EURO-CORDEX dataset is openly available and was fed into the Regional Atlas of the IPCC Sixth Assessment Report. However, this ensemble suffered from several shortcomings, which the community seeks to address in the next phase of production. Chief among these is the oft-cited criticism that the selection of GCMs that provide input to the regional climate models was not rigorous and that the resulting ensemble represents an “ensemble of opportunity.” The present paper provides a description of how the community has addressed these shortcomings. We present a comprehensive, flexible, and traceable evaluation framework and toolkit for assessing the suitability of GCMs for downscaling, using EURO-CORDEX as an example. Its value lies in its explicit recognition of subjectivity and mechanisms implemented to transparently track decision-making. Further, the utility of the framework extends well beyond predownscaling decisions to also include postdownscaling investigations performed by the VIACS communities and beyond, to include researchers investigating such topics as model biases, future constraints, and exploring future storylines. Significance Statement The European Coordinated Regional Climate Downscaling Experiment initiative (EURO-CORDEX) community has created a comprehensive evaluation framework and open-source toolkit for global climate model assessment. These approaches provide a robust, transparent, and traceable approach to both pre- and postdownscaling ensemble designs whose utility extends well beyond the immediate regional climate community. This will enable improved and more nuanced assessments of regional climate change and its impacts.

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Publication Details

Journal
Bulletin of the American Meteorological Society
Published
2025-05-26
DOI
https://doi.org/10.1175/bams-d-23-0189.1
Citations
5
Primary Topic
Climate variability and models
Type
article
Field-Weighted Citation Impact
5.53

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article

GCM Selection and Ensemble Design: Best Practices and Recommendations from the EURO-CORDEX Community

C. McSweeney, Pierre Nabat, Saïd Qasmi, R. Wilcke et al.
5 citations
Bulletin of the American Meteorological Society
Climate variability and models
5.53
article

GCM Selection and Ensemble Design: Best Practices and Recommendations from the EURO-CORDEX Community

C. McSweeney, Pierre Nabat, Saïd Qasmi, R. Wilcke, Swen Brands, Martin Jury, Ole B. Christensen, Silje Lund Sørland, Julien Boé, Eleni Katragkou, Florence Sevault, Lukas Brunner, Katharina Bülow, Andreas Dobler, Douglas Maraun, Rasmus Benestad, Sven Kotlarski, Jesús Fernández, Aurélien Ribes, Guillaume Evin, Tamzin Palmer, Stefan Sobolowski, Thomas Oudar, Samuel Somot, Erasmo Buonomo, Claas Teichmann, Christian Steger, Grigory Nikulin
article en
5 citations

Abstract

Abstract High-resolution climate information is critical for the Vulnerability, Impacts, Adaptation, and Climate Services (VIACS) communities. Coordinated ensembles generated by initiatives like the Coordinated Regional Climate Downscaling Experiment (CORDEX) provide consistent and comparable information for the present and future over all land areas of the globe. This manuscript focuses on the European CORDEX initiative (EURO-CORDEX) and its coordinated effort to build regional climate ensembles for the years to come. In its first phase, EURO-CORDEX produced a rich ensemble of regional climate simulations under different representative concentration pathway scenarios. The EURO-CORDEX dataset is openly available and was fed into the Regional Atlas of the IPCC Sixth Assessment Report. However, this ensemble suffered from several shortcomings, which the community seeks to address in the next phase of production. Chief among these is the oft-cited criticism that the selection of GCMs that provide input to the regional climate models was not rigorous and that the resulting ensemble represents an “ensemble of opportunity.” The present paper provides a description of how the community has addressed these shortcomings. We present a comprehensive, flexible, and traceable evaluation framework and toolkit for assessing the suitability of GCMs for downscaling, using EURO-CORDEX as an example. Its value lies in its explicit recognition of subjectivity and mechanisms implemented to transparently track decision-making. Further, the utility of the framework extends well beyond predownscaling decisions to also include postdownscaling investigations performed by the VIACS communities and beyond, to include researchers investigating such topics as model biases, future constraints, and exploring future storylines. Significance Statement The European Coordinated Regional Climate Downscaling Experiment initiative (EURO-CORDEX) community has created a comprehensive evaluation framework and open-source toolkit for global climate model assessment. These approaches provide a robust, transparent, and traceable approach to both pre- and postdownscaling ensemble designs whose utility extends well beyond the immediate regional climate community. This will enable improved and more nuanced assessments of regional climate change and its impacts.

Bulletin of the American Meteorological SocietyVol. 106(9)
Institut polytechnique de Grenoble (FR), Met Office (GB), Swedish Meteorological and Hydrological Institute (SE), Centre National de la Recherche Scientifique (FR), Norwegian Meteorological Institute (NO), Federal Office of Meteorology and Climatology MeteoSwiss (CH), University of Graz (AT), Universität Hamburg (DE), Deutscher Wetterdienst (DE), Université Fédérale de Toulouse Midi-Pyrénées (FR), Aristotle University of Thessaloniki (GR), Bjerknes Centre for Climate Research (NO), Danish Meteorological Institute (DK), Centre National de Recherches Météorologiques (FR), Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (FR), Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (FR), NORCE Research AS (NO), Météo-France (FR), Institut des Géosciences de l'Environnement (FR), Sweco (Norway) (NO), Helmholtz-Zentrum Hereon (DE), Instituto de Física de Cantabria (ES), Institut de Recherche pour le Développement (FR), Université Grenoble Alpes (FR)
Klima- und Energiefonds, European Commission, Agence Nationale de la Recherche, Hellenic Foundation for Research and Innovation, Ministerio para la Transición Ecológica y el Reto Demográfico, Foreign, Commonwealth and Development Office, HORIZON EUROPE Framework Programme, Agencia Estatal de Investigación
Openalex Percentile: Top 4%
Climate variability and models
5.53
DOIOpen Access PDFOpenAlex
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