Ocean Currents

Surface Currents Surface currents generally occur from 0 to about 400 meters (some are deeper) Deep currents are those whose upper portions remain below the ocean surface 3 major factors that set ocean currents in motion Wind Changes in sea level Variations in water density

Wind Wind transfers energy through friction on the water’s surface as it blows over the water Causes both surface currents and waves A water current will develop if wind blows in the same direction. When wind stops friction will cause the energy from the wind to spread

Changes in water density Changes in sea Level This is driven by pressure gradient force Sea level does change It is an average of low and high tide When the level drops, the current carries water out Similar to changes in sea level Causes a difference in weight and therefore pressure Results in pressure gradient Current flow is below the surface

Gyre Large ocean currents that run into land It is caused by a combination of the coriolis effects the different atmospheric cells There are 5 major gyre One in each major ocean basin