Couallier et al. (2026) Toward robust fine-scale decadal precipitation forecasts through dynamically consistent subsampling

Identification

• Journal: Earth System Dynamics
• Year: 2026
• Date: 2026-08-26
• Authors: Joanne Couallier, Didier Swingedouw, Charlotte Sakarovitch, Théodore Raymond, Ramdane Alkama
• DOI: 10.5194/esd-17-1177-2026

Research Groups

• LyRE (SUEZ), Pessac, France
• EPOC, Pessac, France

Short Summary

This study presents a 5-step framework to improve decadal precipitation forecasts over France by integrating recent advances in large-scale sea-level pressure modes. The approach combines predicted indices with dynamically consistent subsampling of climate model ensemble members.

Objective

• To develop a robust and fine-scale decadal precipitation forecasting system for France, leveraging the relationship between large-scale atmospheric modes and regional hydroclimate variability.

Study Configuration

• Spatial Scale: 8-km grid resolution over France.
• Temporal Scale: Decadal timescale (10-year forecast horizon).

Methodology and Data

• Models used: IPSL-CM6A-LR model, DCPP-A ensemble from CMIP6.
• Data sources: SAFRAN reanalysis dataset for precipitation observations, ERA5 reanalysis dataset for large-scale climate fields.

Main Results

• The study demonstrates improved skill in winter precipitation forecasts over France using the North Atlantic Oscillation (NAO) index, with significant Anomaly Correlation Coefficient across 78% of grid cells.
• Summer skill is weaker but improves notably when combining NAO with the Atlantic Multidecadal Variability (AMV), significant over 48% of grid cells.

Contributions

• This study provides a transferable pathway toward actionable, fine-scale hydroclimate information at the decadal scale, potentially useful for climate services.
• The methodology is adaptable to other regions and variables, offering promising opportunities for improving decadal-scale hydroclimate predictions.

Funding

• This research was funded by [insert funding agencies or projects, e.g., "EU Horizon 2020 project: CLIM4CLIMATE"]

Citation

@article{Couallier2026Toward,
  author = {Couallier, Joanne and Swingedouw, Didier and Sakarovitch, Charlotte and Raymond, Théodore and Alkama, Ramdane},
  title = {Toward robust fine-scale decadal precipitation forecasts through dynamically consistent subsampling},
  journal = {Earth System Dynamics},
  year = {2026},
  doi = {10.5194/esd-17-1177-2026},
  url = {https://doi.org/10.5194/esd-17-1177-2026}
}