Makwana et al. (2025) Spatially Inhomogeneous Phase Change, and Its Effect on Cloud Turbulence

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

Identification

• Journal: Geophysical Research Letters
• Year: 2025
• Date: 2025-11-13
• Authors: Nikitabahen N. Makwana, Bipin Kumar, Yogesh Prasaad Madras Sethuraman, Rama Govindarajan
• DOI: 10.1029/2025gl117378

Research Groups

Not specified in the abstract.

Short Summary

This study demonstrates that small-scale turbulence in clouds is significantly enhanced by inertial droplets, a phenomenon driven by a mismatch in time scales between vortex evacuation and condensation, which generates baroclinic torque and could accelerate raindrop growth.

Objective

• To investigate whether cloud turbulence differs from typical fluid turbulence, specifically if small-scale turbulence is significantly enhanced in clouds by inertial droplets.

Study Configuration

• Spatial Scale: Sub-Kolmogorov to inertial scales (microscale).
• Temporal Scale: Not explicitly quantified in the abstract, but involves a mismatch between vortex evacuation and condensation timescales.

Methodology and Data

• Models used: Numerical simulations; scaling estimates.
• Data sources: Not applicable (theoretical/simulation study).

Main Results

• Small-scale turbulence is significantly enhanced in clouds by inertial droplets, distinguishing it from typical fluid turbulence.
• This enhancement stems from a mismatch in time scales between vortex evacuation and condensation.
• Inertial droplets are centrifuged out of vortical regions faster than condensation can occur, then grow by condensation, releasing latent heat locally.
• Simulations reveal that vortical regions co-locate with cooler temperatures and higher moisture, leading to sharp density gradients at their boundaries.
• These density gradients drive baroclinic torque, which generates small-scale turbulence.
• The time scales involved align with the study's scaling estimates.

Contributions

• Provides an affirmative answer to whether cloud turbulence differs from typical fluid turbulence, identifying inertial droplets as a key enhancing factor.
• Extends previous two-dimensional models by demonstrating turbulence enhancement over inertial scales, not just sub-Kolmogorov scales.
• Identifies a specific mechanism (baroclinic torque driven by density gradients from droplet dynamics) for generating small-scale turbulence in clouds.
• Suggests a potential mechanism for driving rapid raindrop growth.

Funding

Not specified in the abstract.

Citation

@article{Makwana2025Spatially,
  author = {Makwana, Nikitabahen N. and Kumar, Bipin and Sethuraman, Yogesh Prasaad Madras and Govindarajan, Rama},
  title = {Spatially Inhomogeneous Phase Change, and Its Effect on Cloud Turbulence},
  journal = {Geophysical Research Letters},
  year = {2025},
  doi = {10.1029/2025gl117378},
  url = {https://doi.org/10.1029/2025gl117378}
}