Geostrophic Current
D1. Physical and chemical oceanography and marine meteorologyDefinition
Current resulting from geostrophic balance, common in the ocean interior.
A geostrophic current is the flow that results from geostrophic balance, with the pressure-gradient and Coriolis forces in equilibrium. In the Northern Hemisphere the current keeps higher pressure (a sea-surface high) on its right. Oceanographers compute geostrophic shear from horizontal density gradients via the thermal-wind relation, referenced to a level of no motion or to altimetric sea surface height. Western boundary currents such as the Gulf Stream are largely geostrophic.