The evolution of a selection of water particles through a cumulus cloud. Particles start inside a warm bubble near the ground and later hop by chance from one water class to another based on probabilities set by the underlying microphysical exchange rates. Colors indicate different water classes (gray=vapor, cyan=liquid, blue=rain, purple=graupel, green=ice, yellow=snow).
A new framework is introduced to track Lagrangian particles repesenting water molecules in Eulerian large-eddy simulations. The approach allows to study the pathway of water molecules in both physical and microphysical space and is here applied to study the precipitation efficiency of cumulus clouds.