Warm Rain Initiation
How precipitation embryos help clouds cross the size gap to rain
Why is warm rain difficult to initiate?
Condensation typically grows droplets to only 10–15 micrometers, while collision–coalescence becomes efficient closer to 40 micrometers. This size gap is a central obstacle to explaining rapid rain onset.
Can giant aerosols bridge the size gap?
Giant and ultra-giant aerosol particles can activate into unusually large droplets that act as precipitation embryos, begin colliding earlier, and accelerate the coalescence cascade.
What controls the acceleration of rain formation?
Using Lagrangian cloud simulations, I quantify the number and size of precipitation embryos required for earlier rain and examine how their effects interact with turbulence and the surrounding droplet population.
Selected publication
- Lim, Noh, Lee & Hoffmann (2025): The critical number and size of precipitation embryos to accelerate warm rain initiation. Atmospheric Chemistry and Physics