Allwayin et al. (2025) Investigating Characteristic Droplet Size Distributions in Large Eddy Simulations of Stratocumulus Clouds

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

Identification

• Journal: Geophysical Research Letters
• Year: 2025
• Date: 2025-10-16
• Authors: Nithin Allwayin, D. J. Miller, Kamal Kant Chandrakar, Michael L. Larsen, Raymond A. Shaw
• DOI: 10.1029/2025gl116021

Research Groups

Not specified in abstract.

Short Summary

This study investigates the existence and properties of characteristic cloud droplet size distributions within Large-Eddy Simulations (LES) of stratocumulus clouds using both Lagrangian and bin microphysics schemes. It finds localized characteristic distributions in bin microphysics simulations, but notes that simulated clouds are significantly more uniform than observed, potentially due to poorly resolved entrainment interfaces or uniform large-scale forcing in LES.

Objective

• To investigate the existence and properties of characteristic cloud droplet size distributions within Large-Eddy Simulations of stratocumulus clouds using Lagrangian and bin microphysics schemes.

Study Configuration

• Spatial Scale: Cloud-resolving scale (Large-Eddy Simulations of stratocumulus clouds), varying on the scale of the largest convective cell.
• Temporal Scale: Not specified in abstract.

Methodology and Data

• Models used: Large-Eddy Simulations (LES) coupled with Lagrangian and bin microphysics schemes.
• Data sources: Simulation output from LES; comparison made with recent holographic observations.

Main Results

• Characteristic cloud droplet distribution types were identified within LES, revealing localized distributions that vary on the scale of the largest convective cell in simulations using bin microphysics.
• Results from the Lagrangian microphysics scheme hinted at similar behavior regarding characteristic distributions.
• Compared to actual observations, the simulated clouds exhibited much greater uniformity in their droplet size distributions.
• Analysis of the LES results suggests a potential connection between the observed uniformity and the local entrainment rate.
• The study proposes that the poorly resolved entrainment interface in LES or the uniformity of the large-scale forcing could be causes for the simulated uniformity.

Contributions

• Identifies and characterizes localized cloud droplet size distributions within Large-Eddy Simulations, particularly with bin microphysics.
• Highlights a significant discrepancy between the uniformity of simulated cloud droplet distributions and those observed in nature.
• Proposes specific hypotheses (poorly resolved entrainment interface, uniform large-scale forcing) to explain the greater uniformity in LES compared to observations.
• Advances understanding of cloud microphysics representation in LES and its limitations.

Funding

Not specified in abstract.

Citation

@article{Allwayin2025Investigating,
  author = {Allwayin, Nithin and Miller, D. J. and Chandrakar, Kamal Kant and Larsen, Michael L. and Shaw, Raymond A.},
  title = {Investigating Characteristic Droplet Size Distributions in Large Eddy Simulations of Stratocumulus Clouds},
  journal = {Geophysical Research Letters},
  year = {2025},
  doi = {10.1029/2025gl116021},
  url = {https://doi.org/10.1029/2025gl116021}
}