Large deviations and rain showers

TL;DR

This paper uses large-deviation theory to explain the rapid onset of rain showers, showing how rare but significant collision events lead to quick formation of raindrops.

Contribution

It introduces a novel application of large-deviation theory to explain the fast transition from microscopic droplets to raindrops in cumulus clouds.

Findings

Large deviations account for rapid rain initiation.

Rare collision events significantly accelerate raindrop formation.

Theoretical framework matches observed rapid rain onset.

Abstract

Rainfall from ice-free cumulus clouds requires collisions of large numbers of microscopic droplets to create every raindrop. The onset of rain showers can be surprisingly rapid, much faster than the mean time required for a single collision. Large-deviation theory is used to explain this observation.