Clement et al. (2025) A Signal-to-Noise Problem in Model Simulation of Decadal Climate Modes

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Journal of Climate
• Year: 2025
• Date: 2025-11-21
• Authors: Amy Clement, Mark A. Cane, Jeremy M. Klavans, Chengfei He, Lisa N. Murphy
• DOI: 10.1175/jcli-d-25-0190.1

Research Groups

The abstract does not specify individual research groups, labs, or departments, but refers to a collaborative effort involving "over 50 climate models" and "large ensembles of simulations," implying contributions from numerous climate modeling centers worldwide.

Short Summary

This study investigates the influence of external radiative forcing on three major regional decadal climate modes (AMV, NAO, PDO) using large ensembles of over 50 climate models. It finds that radiative forcing is an important component of their observed behavior, but climate models significantly underestimate the amplitude of this forced signal, leading to an erroneous "signal-to-noise problem" that obscures predictable trends.

Objective

• To estimate the magnitude of the radiatively forced response (signal) compared to internal fluctuations (noise) in three major regional decadal climate modes: Atlantic Multidecadal Variability (AMV), the North Atlantic Oscillation (NAO), and the Pacific Decadal Oscillation (PDO), using climate model simulations and observations.

Study Configuration

• Spatial Scale: Regional to hemispheric (Atlantic, North Atlantic, Pacific regions).
• Temporal Scale: Decadal variability, historical period simulations, recent decades.

Methodology and Data

• Models used: Over 50 climate models, used in large ensemble simulations.
• Data sources: Large ensembles of historical period simulations from climate models, and observations of regional climate modes.

Main Results

• Strong agreement in recent decades between the observed time history of AMV, NAO, and PDO and their simulated response to radiative forcing.
• The signal of radiative forcing is an important part of the observed behavior of these regional climate modes.
• The amplitude of the radiatively forced signal is consistently smaller in models than in observations for all three modes.
• This erroneously small forced signal in models is overwhelmed by internally generated noise in any single model run, leading to a "signal-to-noise problem."
• This error creates a mistaken impression of unpredictable decadal climate variability, despite radiatively forced trends.

Contributions

• Provides strong evidence that external radiative forcing significantly influences major regional decadal climate modes, challenging the historical understanding of them as purely internal fluctuations.
• Identifies and quantifies a critical "signal-to-noise problem" in climate models, where the forced signal of regional climate modes is underestimated, leading to misinterpretations of their predictability.
• Highlights the implications of this model error for understanding past and future regional decadal climate variability.

Funding

The abstract does not provide information regarding specific funding projects, programs, or reference codes.

Citation

@article{Clement2025SignaltoNoise,
  author = {Clement, Amy and Cane, Mark A. and Klavans, Jeremy M. and He, Chengfei and Murphy, Lisa N.},
  title = {A Signal-to-Noise Problem in Model Simulation of Decadal Climate Modes},
  journal = {Journal of Climate},
  year = {2025},
  doi = {10.1175/jcli-d-25-0190.1},
  url = {https://doi.org/10.1175/jcli-d-25-0190.1}
}