Highly localized droplet clustering in shallow cumulus clouds

Authors

• Birte Thiede, Max Planck Institute for Dynamics and Self-Organization
• Michael L. Larsen, College of Charleston
• Freja Nordsiek, Max Planck Institute for Dynamics and Self-Organization
• Oliver Schlenczek, Max Planck Institute for Dynamics and Self-Organization
• Yewon Kim, Max Planck Institute for Dynamics and Self-Organization
• Eberhard Bodenschatz, Max Planck Institute for Dynamics and Self-Organization
• Gholamhossein Bagheri, Max Planck Institute for Dynamics and Self-Organization

Document Type

Article

Publication Date

8-11-2026

Abstract

The size and spatial clustering of water droplets in warm clouds influence cloud evolution and radiation properties and thus are of fundamental importance for the Earth’s energy balance and water cycle. Some proposed mechanisms for droplet growth and precipitation initiation in warm clouds require strong droplet clustering. Resolving such clustering on sub-cm scales remains a challenge. The most detailed observations, collected from aircraft, showed weak mm-scale droplet clustering averaged over kilometer scales in stratocumulus clouds. Here we present spatially resolved in-situ holographic measurements from a tethered aerostat, demonstrating that clustering in shallow cumulus clouds is significantly stronger and far more localized than previously thought. These findings challenge current cloud microphysics frameworks, with implications for precipitation initiation and cloud modeling.

Publication Title

Proceedings of the National Academy of Sciences of the United States of America

Recommended Citation

Thiede, B., Larsen, M., Nordsiek, F., Schlenczek, O., Kim, Y., Bodenschatz, E., & Bagheri, G. (2026). Highly localized droplet clustering in shallow cumulus clouds. Proceedings of the National Academy of Sciences of the United States of America, 123(32). http://doi.org/10.1073/pnas.2602976123
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p2/2902