Geostrophic flow in air or water is a zero-frequency inertial wave. A useful heuristic is to imagine air starting from rest, experiencing a force directed from areas of high pressure toward areas of low pressure, called the pressure gradient force.

A geostrophic current is an oceanic current in which the pressure gradient force is balanced by the Coriolis effect. The direction of geostrophic flow is parallel to the isobars, with the high pressure to the right of the flow in the Northern Hemisphere, and the high pressure to the left in the Southern Hemisphere.

The horizontal movement of surface water arising from a balance between the pressure gradient force and the Coriolis force is known as geostrophic flow. As noted earlier, viewed from above, geostrophic flow in a subtropical gyre is clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.

As the water flows “downhill” away from the gyre center, it is deflected to the right by the Coriolis force. This results in a clockwise current around the central “hill” called geostrophic flow, which moves in the same direction as the rotating gyre.

2024年6月10日 · As the water flows “downhill” away from the gyre center, it is deflected to the right by the Coriolis force. This results in a clockwise current around the central “hill” called geostrophic flow, which moves in the same direction as the rotating gyre.

2006年4月25日 · Barotropic flow occurs when levels of constant pressure in the ocean are always parallel to the surfaces of constant density. Note, some authors call the vertically averaged flow the barotropic component of the flow.

Geostrophic motion, fluid flow in a direction parallel to lines of equal pressure (isobars) in a rotating system, such as the Earth. Such flow is produced by the balance of the Coriolis force (q.v.; caused by the Earth’s rotation) and the pressure-gradient force.

Understand “rules of thumb” for geostrophic flow and how they apply to water flow, isobars, and isopycnals