Stuivenvolt-Allen et al. (2026) The North American CORDEX-CMIP6 WRF evaluation run: comparing historical simulations from 25 km to convection-permitting scales

Identification

• Journal: Geoscientific model development
• Year: 2026
• Date: 2026-09-23
• Authors: Jacob Stuivenvolt-Allen, Trude Eidhammer, Rachel McCrary, Melissa Sue Bukovsky, Stefan Rahimi, Hsin-I. Chang, Seth McGinnis
• DOI: 10.5194/gmd-19-8995-2026

Research Groups

• National Center for Atmospheric Research, Boulder, CO, USA
• Haub School of Environment and Natural Resources, University of Wyoming, Laramie, WY, USA
• Department of Atmospheric Science, University of Wyoming, Laramie, WY, USA
• Department of Hydrology and Atmospheric Science, University of Arizona, Tucson, AZ, USA

Short Summary

This study evaluates the performance of a high-resolution regional climate simulation for North America (NA) as part of the Coordinated Regional Downscaling Experiment (CORDEX). The new NA-CORDEX CMIP6 simulation at 12 km resolution is compared to an earlier NA-CORDEX CMIP5 simulation (25 km) and a convection-permitting CONUS-404 simulation (4 km).

Objective

• Assess improvements from the corresponding previous-generation simulation in mean climatological biases, diurnal precipitation processes, seasonal hydroclimate, snow, and extreme events.

Study Configuration

• Spatial Scale: Continental-scale climate assessment for North America.
• Temporal Scale: Historical simulations from 1980 to 2023.

Methodology and Data

• Models used: WRF model version 4.6.1 with Noah-MP land surface model, RRTMG radiation scheme, and Thompson microphysics scheme.
• Data sources: ERA5 reanalysis for lateral boundary conditions, surface variables, sea surface temperature, and sea ice fraction.

Main Results

• The new NA-CORDEX CMIP6 simulation at 12 km resolution reduces mean differences in temperature and precipitation compared to reanalysis and other observationally based datasets.
• Improvements are seen in the magnitude and timing of the diurnal precipitation cycle across North America.
• Extreme precipitation rates are well captured at 12 km when compared to convection-permitting simulations.

Contributions

• This study provides a practical balance between computational efficiency and physical realism for continental-scale climate assessment.
• The results highlight the importance of high-resolution regional climate simulations for accurately representing extreme events and diurnal processes.

Funding

• This research was supported by the National Science Foundation (NSF) under grant number [insert grant number].

Citation

@article{StuivenvoltAllen2026North,
  author = {Stuivenvolt-Allen, Jacob and Eidhammer, Trude and McCrary, Rachel and Bukovsky, Melissa Sue and Rahimi, Stefan and Chang, Hsin-I. and McGinnis, Seth},
  title = {The North American CORDEX-CMIP6 WRF evaluation run: comparing historical simulations from 25 km to convection-permitting scales},
  journal = {Geoscientific model development},
  year = {2026},
  doi = {10.5194/gmd-19-8995-2026},
  url = {https://doi.org/10.5194/gmd-19-8995-2026}
}