Ocean currents and processes

gyre

A large-scale pattern of mid-latitude currents flowing around the edges of an ocean basin that moves clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere (most often bordered by land).

western boundary currents

Deep, narrow and swift poleward-flowing warm currents on the western side of all subtropical gyres

Surface currents

Driven by the prevailing winds in each hemisphere.

Ocean circulation in gyres

Surface winds, heat from the sun, gravity, and the Coriolis effect combine to drive surface currents clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. Most gyres are contained in ocean basins by major land masses.

There are five large western boundary currents

The Gulf Stream (in the North Atlantic). the Japan or Kurishio Current (in the North Pacific), the Brazil current (in the South Atlantic), the Agulhas Current ( in the Indian Ocean), and the East Australian Current (in the South Pacific).

Ekman transport

The change in current direction with depth caused by the varying effect of surface friction at 90 degrees to the wind direction at the surface

upwelling

The movement of deep, cold, and nutrient-rich water to the surface driven by offshore currents in some places.

Sverdrup (SV)

measures the volume of water transported in ocean currents