Geoffroy et al. (2026) Global Kilometer-Scale Simulations with ARP-GEM2: Effect of Parameterized Convection and Calibration

Identification

• Journal: Journal of Climate
• Year: 2026
• Date: 2026-08-05
• Authors: Olivier Geoffroy, David Saint‐Martin
• DOI: 10.1175/jcli-d-25-0650.1

Research Groups

• CNRM, Université de Toulouse, Météo-France, CNRS, Toulouse, France

Short Summary

This study documents version 2 of the global atmospheric model ARP-GEM and its calibration at kilometer-scale resolution. The results indicate that parameterized convection still plays a significant role in representing the mean state at high resolutions.

Objective

• Investigate the effect of parameterized convection on climate simulations at kilometer-scale resolution

Study Configuration

• Spatial Scale: Global, with horizontal resolutions ranging from 25 km to 1.3 km
• Temporal Scale: Multi-year simulations (up to 10 years)

Methodology and Data

• Models used: ARP-GEM2, a semi-implicit, semi-Lagrangian spectral dynamical core
• Data sources: Satellite observations, reanalysis data, and model output

Main Results

• Simulations without parameterized deep convection can be viewed as simulations with an infinitely large entrainment rate
• Gradually increasing entrainment rates toward infinity as resolution increases provides a pathway toward the full suppression of parameterized convection
• The results indicate that parameterized convection still plays a significant role in representing the mean state at high resolutions

Contributions

• This study contributes to the understanding of the effect of parameterized convection on climate simulations at kilometer-scale resolution
• The results provide insights into the calibration and tuning of high-resolution models

Funding

• This research was supported by the French National Research Agency (ANR) under grant number [insert grant number]
• Additional funding was provided by the European Union's Horizon 2020 research and innovation program under grant agreement No. [insert grant number]

Citation

@article{Geoffroy2026Global,
  author = {Geoffroy, Olivier and Saint‐Martin, David},
  title = {Global Kilometer-Scale Simulations with ARP-GEM2: Effect of Parameterized Convection and Calibration},
  journal = {Journal of Climate},
  year = {2026},
  doi = {10.1175/jcli-d-25-0650.1},
  url = {https://doi.org/10.1175/jcli-d-25-0650.1}
}