Notes – Surface Currents GeoWords Notes – Surface Currents Ocean Current: A predominantly horizontal movement of ocean water Gyres: a circular motion of water in each of the major ocean basins ALL currents carry matter and energy (heat) from one part of the ocean to another. Surface currents flow much faster than deep water currents Make up about 10% of all ocean water Range in depth from 200m-1000m Flow over long distances. Form large circulation cells called gyres. 5 major gyres Clockwise in N. Hemisphere Counter-clockwise in the S. Hemisphere

Currents on western sides are warm Currents on eastern sides are cold Gyres are important to climate because they move heat energy from the low latitudes (tropics) to the high latitudes (poles). Currents on western sides are warm Ex. Gulf Stream, Kuroshio, East Australian Currents on eastern sides are cold Ex. California, Peru, Canary

Factors Affecting Surface Currents Friction caused by winds Gravity Coriolis Effect (Earth’s Rotation) Continental Barriers

Notes – Surface Currents GeoWords Notes – Surface Currents Upwelling: The upward movement of ocean water from deep in the ocean to the surface.

Notes – Surface Currents GeoWords Notes – Surface Currents Downwelling: the downward movement of ocean water from the surface. Occur when surface winds blow toward the shore and cause water to pile up along the coast OR when a wind blowing parallel to the coast changes direction

5.6 Surface Currents Questions Describe the factors that can affect surface currents. What is a gyre? How do surface currents help regulate the temperature of the planet? How does the direction of flow differ in the Northern and Southern Hemispheres? What is the major difference between eastern boundary currents and western boundary currents? Explain the relationship between the North Equatorial current and the Kuroshio Current. Describe the gyre found in the North Atlantic ocean. (include each current’s - name, temperature, and general direction) Explain why the Antarctic Circumpolar Current does not flow into a gyre but can circle the Earth. Why does northwestern Europe have a far warmer climate than the regions of Canada that have the same latitude? Draw a diagram that explains why upwelling occurs. What cold water currents near coastlines might indicate sites of upwelling? How does upwelling promote the abundance of life in the surface waters of the ocean?