Quasi-geostrophic (QG) Theory is one of the most important concepts put forth in the late 1940s (Sutcliff 1947, Charney 1948) for interpreting the present state of the atmosphere, and evaluating short-term tendencies of synoptic scale systems. Advantages of QG Theory are that it reduces the governing equations to a set of easily understood relationships, which are applicable to synoptic weather. It links dynamics and thermodynamics together into a nice compact package, and provides a method of understanding some of the complexities of the atmosphere. Of course, it is crucial to understand the underlying assumptions: hydrostatic balance, no friction, adiabatic motion (no radiation, latent heat, or sensible heat exchange), and the ageostrophic wind is much less than the geostrophic wind, etc. In spite of these drawbacks, QG theory is still very useful, especially to the new student of atmospheric processes.
The Forecast System Laboratory (FSL), in cooperation with the National Weather Service (NWS), has developed Display 3-Dimensional workstation (D3D). D3D allows users to view real-time meteorological model data in a three-dimensional interactive display. D3D has evolved from the WFO-Advanced D2D system, which is currently the operational interactive display software on Advanced Weather Interactive Processing System (AWIPS) installed in all NWS forecast offices.
This paper will show how D3D can be used in a training environment. The terms in the QG omega equation, such as temperature advection and vorticity advection can be visualized and compared to omega. Other QG quantities such as potential vorticity and divergence of Q will also be examined.