Despite their central role in the climate system, our scientific understanding of clouds is still limited because small-scale processes such as turbulence, radiation, and microphysics are complex and not adequately captured in models. This project focuses in particular on flat trade wind cumulus clouds and Arctic mixed-phase clouds in order to improve our understanding of the influence of these processes. Therefore, a newly developed modeling approach is used that combines direct numerical simulation and large eddy simulation, thus mapping all relevant scales from the smallest turbulence to entire cloud fields. The aim of the project is to fully quantify the influence of small-scale processes on cloud development, radiation properties, and thus on the global climate system.