Fabian Hoffmann is working with Graham Feingold, and others at CIRES and NOAA, to broaden our understanding of clouds in the climate system. He focuses on the process of entrainment and mixing, i.e., the engulfment of cloud-free air into clouds. This processes affect the micro- and macrophysical properties of clouds by changing number and size of droplets, and hence a cloud’s ability to reflect sunlight as well as its probability to produce rain. For this purpose, Fabian is extending his Lagrangian cloud model, a novel method to represent cloud microphysics by individually simulated particles, by a detailed representation of entrainment and mixing. This approach not only fosters our process-level understanding of entrainment and mixing, e.g., on how and where mixing takes place inside a cloud, but also enables an assessment of the macrophysical properties of an entire cloud field, i.e., at a scale at which entrainment and mixing are usually crudely parameterized in other models.