Dynamics and cirrus clouds - multiscale modelling

Cirrus clouds represent a multiscale system with processes on the microscale (ice formation, growth) over small scale (turbulence) to the mesoscale (waves, convection) and even to the large scale (e.g. warm conveyor belts). Thus, it is quite difficult to study the impact of processes on different scales on the life cycle of cirrus clouds and even more to identify the dominant processes.

For studying cirrus clouds in a more controlled multiscale environment, a new method is applied. The EULAG model (Prusa et al., 2008) uses the usual perturbation form for solving the anelastic equations. Although the background state is usually assumed to be constant, time-dependent (and even spatially dependent) environmental states are possible, leading to new forcing terms for the equations in order to represent the changing (large scale) states. We use this new method to investigate the formation and evolution of cirrus clouds in time-dependent flows. This work is collaboration with Dr. Piotr Smolarkiewicz (NCAR) and Dr. Andreas Dörnbrack (DLR).