- Stratiform Cloud Processes and Precipitation
- Convective Cloud Processes and Precipitation
- Types of Precipitation
- Aerosols and Greenhouse Gases
The physical processes associated with radiative transfer, convection, clouds, turbulent mixing, sub grid-scale orographic drag and non-orographic gravity wave drag have a strong impact on the large-scale flow of the atmosphere. However, these mechanisms are often active at scales smaller than the resolved scales of the model grid. The effect of sub-scale physical processes on weather systems is expressed in the model in terms of resolved model variables using parameterisation. This involves both statistical methods and simplified mathematical-physical models, (e.g. the air closest to the earth’s surface exchanges heat with the surface through turbulent diffusion or convection, which adjusts stability in the lowest layers).
Additional Sources of Information
(Note: In older material there may be references to issues that have subsequently been addressed)
- Watch a comprehensive lecture on model physics (30sec delay before video begins).
- View ECMWF eLearning module on parameterisation of sub-grid processes.