Small-scale atmospheric physical processes on a broad range of time and spatial scales (containing atmospheric turbulence, atmopshere-soil-vegetation interactions, gravity waves, shallow and deep convection, mesoscale flows) strongly influence weather and climate, particularly also on high impact weather and hydrological hazards. The nature and interactions of these processes should be well-understood and represented on the different scales to enable accurate and skilled weather forecasting, as well as reliable climate simulation and scenario studies. Additionally, increasing resolution of NWP and climate models is setting new requirements to parameterization schemes and data availability as model inputs or for their validation.

This session covers research into the understanding of small-scale processes from either a conceptual, or modelling or observational perspective, their role and interactions and finally their implementation in atmospheric modelling. Furthermore, experimental validation and modelling of local circulations can be discussed.

Papers dealing with the following topics (but not exclusively) are invited:
• The general problem of parameterizing small-scale physical processes
• Representation of boundary layers in atmospheric models
• Sensitivity of models to the description of land-surface heterogeneity and land-surface interactions (including flux aggregation)
• Orographic effects: form drag, wave drag and flow blocking, gravity waves
• Limited Area Modelling, and observation network issues
• Interactions between local/mesoscale circulations and larger scale patterns
• Validation of surface exchange processes for various types of terrain
• Large Eddy Simulation, observational analysis, and parameterization of shallow and deep convection.
• The sensitivity of small scale processes to the land surface properties and the impact on the atmospheric circulation
• Organization of deep convection across differing atmospheric scales
• Transport/interaction between aerosols and boundary layer processes
• Uncertainty and probabilities of predicting precipitation on the "convection permitting" scales.
• Stochastic boundary layer parameterizations