Introduction
This module covers:
- The role of radiant energy (short and longwave radiation) and the influence of clouds, moisture, and trace gases on radiative transfer in the atmosphere.
- The role of surface characteristics in determining the amount and partitioning of solar radiation reaching the surface (land versus water, snow, and ice; and vegetation and soil moisture effects on surface water and energy balances).
- The role of turbulent transfer in the planetary boundary layer (from surface to free atmosphere) and in the free atmosphere (vertical and horizontal diffusion) in response to radiative forcing.
Working through the material will help you to:
- Develop a basic understanding of how radiation and associated processes are emulated in NWP models.
- Understand when model physics are most important to the model forecast (versus model dynamics).
- Understand that model physics are specifically tuned to work best in certain situations and specific models.
- Understand that model physics parameterizations affect other parameterizations, model dynamics, and data assimilation, which may result in feedbacks.
- Identify impacts of model physics and their errors on model forecasts both at and around the forecast location.
- Identify effects that are smaller than the model can emulate (for example, the resolution of surface characteristics is coarse but real effects occur at fine resolution).
The module is structured as follows:
- Processes presents an overview of radiative, land surface, sea surface, and turbulent processes.
- Physics Parameters presents an interactive environment for exploring the effect of physics parameters on the surface forecast. Since the importance of model physics to specific forecast problems varies greatly throughout the day from one season (or air mass) to the next, this section focuses both on how models emulate the diurnal cycle and on how model physics impact sensible weather forecasts. It uses data from a single column model forced with real advection data from observations.
- Operational Tips presents tips related to model physics that will help you make better use of model forecasts.
- Exercises presents a series of questions that should help you integrate the information presented in the module and apply it operationally.
- References gives supporting references for the module.