ESR11 - Lagrangian estimates of entrainment rates in clouds
Objectives
- Computing balloon Lagrangian trajectories from LES outputs in shallow cumulus and stratocumulus conditions.
- Comparison with data from mini radioprobes from WP2.
- Specific adjustement to Lagrangian trajectories will have to be implemented to take into account balloon dynamics.
- Rates of mixing will be estimated at the interfaces of cloudy and clear air.
Expected Results
Transfer of knowledge from microprobes to the weather/climate modelling community.
Planned secondment(s)
- ENV (Torino) Month 9: radiosondes for devices for trajectories measurements
- ISAC & POLITO (Torino) Month 10: trajectory computations methods, LES modelling
- MPG (Goettingen) Month 17-18: comparison with experiments
- MPIM (Bonn) Month 27-28
The general objective of the thesis is to perform sensitivity studies of the representation of the convective clouds in a high-resolution model with the aim of acquiring knowledge and of proposing improvements of the convective parameterization in GCM. The work will concern on the shallow cloudiness that can play an important role in the origin in the organization of the deep convection, especially at the diurnal time scale. The study will be focused on the formation of clouds over an island. Several physical processes at the origin of the variability of the cloud cover characteristics will be examined such as the role of dry air entrainment (cloud dissipation), the role of aerosol concentration (physical and microphysical processes), the role of surface conditions, of the size and orography of the island (and their mesoscale effects), the larger scale conditions Technically, the work will be based on simulations of shallow and deep cloudiness in cloud resolving models (CRM) and Large Eddy Simulations (LES) that will be specifically performed, or that already exists in the framework of collaborative projects. These models will give information on the physical sources of variability of the shallow convective cloudiness.