Geostrophic flow in current gyres
Consider the dynamic topographic high in a low-latitude current gyre
- Surface water tends to move downhill, radially away from topographic high in center of gyre
- Surface water feels the Coriolis effect, & is deflected to right (or left)
- For water in gyre, Coriolis effect tends to move water toward center of gyre
- Eventually, the tendency to flow toward the center of gyre (due to Coriolis effect) equals the tendency to flow toward periphery (due to gravity), so water flows around gyre along a line of constant sea surface elevation
At that time, have geostrophic flow or say that flow is in geostrophic balance