Werapitiya et al. (2025) Extratropical Cloud Feedback Constrained by Cloud Sources and Sinks in Cyclones

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

Identification

• Journal: Journal of Climate
• Year: 2025
• Date: 2025-11-11
• Authors: Geethma Werapitiya, Daniel T. McCoy, Gregory S. Elsaesser, Andrew Gettelman, Trude Eidhammer, Travis Aerenson, Ci Song, Jingbo Wu
• DOI: 10.1175/jcli-d-24-0607.1

Research Groups

• Community Atmosphere Model (CAM) development team (likely NCAR/UCAR)
• Community Earth System Model (CESM) development team (likely NCAR/UCAR)

Short Summary

This study constrains Southern Ocean liquid water path (LWP) response and shortwave cloud feedback (SW FB) in global climate models using observational data and a perturbed parameter ensemble, finding that observations suggest a more positive SW FB and do not reject high climate sensitivity models.

Objective

• To constrain liquid water path (LWP) response to warming and shortwave cloud feedback (SW FB) in the Southern Ocean (50°–80°S) using precipitation efficiency and albedo susceptibility, thereby improving predictions of future climate.

Study Configuration

• Spatial Scale: Southern Ocean (50°–80°S), focusing on extratropical cyclones.
• Temporal Scale: Climatological, aiming to constrain long-term climate response and future climate predictions.

Methodology and Data

• Models used:
  • Community Atmosphere Model, version 6 (CAM6) in a perturbed parameter ensemble (PPE).
  • Community Earth System Model, version 2 (CESM2) for comparison.
  • Gaussian process regression to emulate model response.
• Data sources:
  • Clouds and the Earth’s Radiant Energy System (CERES) observations.
  • Multisensor Advanced Climatology of LWP (MAC-LWP).
  • Observations of clouds and moisture convergence.
  • Precipitation in extratropical cyclones.

Main Results

• New estimates of Southern Ocean LWP reduce the PPE range by 66%–72%.
• The estimated range for shortwave cloud radiative effect is consequently reduced by 27%–34% compared to the PPE range.
• Observations suggest a more positive Southern Ocean SW FB than that simulated by CESM2.
• The observational constraints do not reject the high climate sensitivity global climate models emerging from the Coupled Model Intercomparison Project phase 6 (CMIP6).

Contributions

• Introduces a novel approach using precipitation efficiency and albedo susceptibility to constrain LWP response and SW FB in the Southern Ocean.
• Significantly reduces the uncertainty range in Southern Ocean LWP and shortwave cloud radiative effect in climate models.
• Provides observational evidence that supports a more positive Southern Ocean SW FB, offering critical insight into the debate surrounding high equilibrium climate sensitivity in the latest generation of GCMs.

Funding

Not specified in the abstract.

Citation

@article{Werapitiya2025Extratropical,
  author = {Werapitiya, Geethma and McCoy, Daniel T. and Elsaesser, Gregory S. and Gettelman, Andrew and Eidhammer, Trude and Aerenson, Travis and Song, Ci and Wu, Jingbo},
  title = {Extratropical Cloud Feedback Constrained by Cloud Sources and Sinks in Cyclones},
  journal = {Journal of Climate},
  year = {2025},
  doi = {10.1175/jcli-d-24-0607.1},
  url = {https://doi.org/10.1175/jcli-d-24-0607.1}
}