Past exam of the classical mechanics course of Part B of the physics course of the University of Oxford / 2016 / 1 / a / Solution

In a frame rotating with angular velocity $\mathbf{\Omega }$, a particle of relative velocity $\mathbf{v}$ experiences the Coriolis forceFor nearly horizontal atmospheric motion, the relevant vertical rotation component is $\Omega \sin \ell$, with latitude $\ell$. In the northern hemisphere the horizontal deflection is to the right of the motion. A low-pressure center produces an inward pressure-gradient force; an anticlockwise circulation has an outward Coriolis force to oppose it. A high-pressure center instead supports clockwise circulation, with inward Coriolis force opposing the outward pressure-gradient force.

The sense reverses in the southern hemisphere. There, anticlockwise circulation is anticyclonic and corresponds to high atmospheric pressure. HenceThis is the large-scale rotating-fluid interpretation; friction, centrifugal acceleration and departures from ideal balance modify actual wind profiles. NASA's description independently identifies the southern, counterclockwise Great Red Spot as a high-pressure system.^[ref]