Noyelle et al. (2026) Does Oceanic Variability Explain the Intensity of Megadroughts and Megapluvials in the CESM2 Climate Model?

Identification

• Journal: Journal of Climate
• Year: 2026
• Date: 2026-08-11
• Authors: Robin Noyelle, Erich Markus Fischer, Reto Knutti, Heini Wernli
• DOI: 10.1175/jcli-d-26-0237.1

Research Groups

• Institute for Atmospheric and Climate Science, ETH Zürich (Switzerland)

Short Summary

This study investigates the role of oceanic variability in explaining the intensity of megadroughts and megapluvials in the CESM2 climate model. The authors find that natural variability in the atmosphere is the primary driver of these events outside ENSO-influenced regions.

Objective

• Investigate the relationship between oceanic variability and the intensity of megadroughts and megapluvials in the CESM2 climate model.

Study Configuration

• Spatial Scale: Global, with a focus on regions outside ENSO-influenced areas.
• Temporal Scale: Multi-year to decadal time scales.

Methodology and Data

• Models used: CESM2 fully-coupled climate model.
• Data sources: Preindustrial run of the CESM2 model.

Main Results

• The study finds that natural variability in the atmosphere is the primary driver of megadroughts and megapluvials outside ENSO-influenced regions.
• Interannual correlations in accumulated precipitation are weak, suggesting that multi-year extreme precipitation events arise as a succession of independent yearly events.
• A linear regularized model shows that anomalous SSTs do not explain the intensity of dry and wet events.

Contributions

• This study provides new insights into the drivers of megadroughts and megapluvials in climate models, highlighting the importance of atmospheric natural variability.
• The results suggest that key physical mechanisms linking SSTs and precipitation may be missing or improperly represented in the CESM2 model.

Funding

• This research was supported by [project/program name] with reference code [reference code].

Citation

@article{Noyelle2026Does,
  author = {Noyelle, Robin and Fischer, Erich Markus and Knutti, Reto and Wernli, Heini},
  title = {Does Oceanic Variability Explain the Intensity of Megadroughts and Megapluvials in the CESM2 Climate Model?},
  journal = {Journal of Climate},
  year = {2026},
  doi = {10.1175/jcli-d-26-0237.1},
  url = {https://doi.org/10.1175/jcli-d-26-0237.1}
}