Toward exascale climate modelling: a python DSL approach to ICON's (icosahedral non-hydrostatic) dynamical core (icon-exclaim v0.2.0)
Abstract. A refactored atmospheric dynamical core of the ICON model implemented in GT4Py, a Python-based domain-specific language designed for performance portability across heterogeneous CPU-GPU architectures, is presented. Integrated within the existing Fortran infrastructure, the new GT4Py dynamical core is shown to exceed ICON OpenACC performance. A multi-tiered testing strategy has been implemented to ensure numerical correctness and scientific reliability of the model code. Validation has been performed through global aquaplanet and prescribed sea-surface temperature simulations to demonstrate model's capability to simulate mesoscale and its interaction with the larger-scale at km-scale grid spacing. This work establishes a foundation for architecture-agnostic ICON global climate and weather model, and highlights poor strong scaling as a potential bottleneck in scaling toward exascale performance.
Authors
- Oliver Fuhrer (ORCID: https://orcid.org/0000-0002-0682-1374)
- Hannes Vogt
- M. Rothlin
- Mauro Bianco
- A. Jocksch (ORCID: https://orcid.org/0000-0002-3327-4230)
- Abishek Gopal (ORCID: https://orcid.org/0000-0002-7300-6740)
- Xavier Lapillonne (ORCID: https://orcid.org/0000-0001-6114-4321)
- Andreas F. Prein (ORCID: https://orcid.org/0000-0001-6250-179X)
- Sebastian Schemm (ORCID: https://orcid.org/0000-0002-1601-5683)
- T. C. Schulthess (ORCID: https://orcid.org/0000-0002-1086-5812)
- Robert C. J. Wills (ORCID: https://orcid.org/0000-0002-7776-2076)
- Clarissa Kroll
- Giacomo Serafini
- Anurag Dipankar (ORCID: https://orcid.org/0000-0002-1410-4324)
- Praveen Kumar Pothapakula (ORCID: https://orcid.org/0000-0002-5654-7975)
- Till Ehrengruber
- Carlos Osuna (ORCID: https://orcid.org/0000-0002-9896-9957)
- Daniel Hupp
- Nicoletta Farabullini
- Mona Bukenberger
- Chia Rui Ong
- Christoph Müller
- Matthieu Leclair
- Nicolas Gruber
- Christoph Schär
- Magdalena Luz
- William Sawyer
- Samuel Kellerhals
- Ben Weber
Institutions
- NSF National Center for Atmospheric Research (US)
- Federal Office of Meteorology and Climatology MeteoSwiss (CH)
- University of Cambridge (GB)
- ETH Zurich (CH)
- Institute for Biomedical Engineering (CH)
- Supercomputing Systems (Switzerland) (CH)
Publication Details
- Journal
- Geoscientific model development
- Published
- 2026-01-22
- DOI
- https://doi.org/10.5194/gmd-19-713-2026
- Primary Topic
- Meteorological Phenomena and Simulations
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Eidgenössische Technische Hochschule Zürich
- National Supercomputing Center, Korea Institute of Science and Technology Information