Soft Matter and Complex Systems Seminar

Clouds are dispersions of drops and ice particles embedded in and interacting with a complex turbulent flow. They are highly non-stationary, inhomogeneous, and intermittent, and embody an enormous range of spatial and temporal scales. Strong couplings across those scales between turbulent fluid dynamics and microphysical processes are integral to cloud evolution. Turbulence drives entrainment, stirring, and mixing in clouds, resulting in strong fluctuations in temperature, humidity, aerosol concentration, and cloud particle growth and decay. It couples to phase transition processes as well as particle collisions and breakup. All these processes feed back on the turbulent flow by buoyancy and drag forces and affect cloud dynamical processes up to the largest scales. Examples of several specific cloud-turbulence interactions, investigated by the author by means of laboratory and in-situ measurements as well as numerical simulations, will be presented and discussed.