What does Wind & Pressure cover?
Wind is driven by pressure differences. This topic covers how pressure systems generate wind, the balance behind the geostrophic and gradient wind, and the local effects (sea breezes, mountain winds, friction) that change wind near the surface.
What this subject covers
- Pressure gradient force and the Coriolis effect
- Geostrophic and gradient wind
- Surface friction and wind backing/veering
- Local winds: sea/land breeze, katabatic, föhn
Study tip
Get the hemisphere conventions right: wind backs and veers in opposite senses in the two hemispheres, and exam questions deliberately test this.
Frequently asked questions
What is the geostrophic wind?
A theoretical wind blowing parallel to straight isobars, where the pressure gradient force is balanced by the Coriolis effect — a good approximation above the friction layer.
Why does surface wind differ from the wind aloft?
Friction slows the surface wind and changes its direction (backing in the Northern Hemisphere), so it crosses the isobars towards low pressure.
