Module description
This course considers motion in the atmosphere from a fluid-mechanical perspective, showing how geostrophic and hydrostatic balance leads to simplification of the nonlinear basic equations. Applications are presented in the context of synoptic weather systems and fronts. Vorticity and potential vorticity are introduced as fundamental dynamical properties of the flow. Wave motion in the atmosphere is introduced within a physical framework, with application to gravity waves, tides and planetary waves.

Learning outcomes
After taking this module students should be able to:

• understand geostrophic and hydrostatic balance and solve simple problems using these concepts
• derive information from a weather chart
• understand the fundamental link between vorticity and vertical motion in the atmosphere
• understand the structure of a midlatitude cyclone and the central role played by fronts in such a structure
• understand the nature of gravity waves and their role in the atmospheric circulation.
• understand the origin and nature of planetary waves and their role in the atmospheric circulation.

Additional learning activities
Computer-aided learning packages for meteorology.
Videos on satellite observations of air motion.

Outline syllabus
The dynamical equations of atmospheric flow: inclusion of Coriolis acceleration.
Scale analysis: horizontal momentum equations, hydrostatic eqn.
Pressure co-ordinates.
Geostrophic and gradient wind.
Thermal Wind.
The chart as a means of displaying information.
Vorticity, the vorticity equation, potential vorticity.
Applications of the conservation of potential vorticity.
Fronts.
General Circulation in the troposphere.
Overview of wave motion in the atmosphere: restoring forces.
Gravity waves: simple theory, asymptotic equation.
Gravity wave saturation and spectra.
Transport of momentum by gravity waves.
Simple theory of atmospheric tides.
Planetary waves: free modes (Rossby waves), forced modes.
Transport by planetary waves.