Ocean currents are propelled by various forces. Such forces can include the wind, tidal patterns due to the gravitational pull from the sun and moon, the Coriolis force and water temperature. An ocean current can move for many miles. The path a current follows is usually consistent.
Wind can propel ocean currents to move due to friction. Depending on the Earth's rotation, winds can move the top surface of the ocean creating surface currents. A surface current will then form what is known as a gyre. A gyre is a spiral movement formed on an ocean's surface.
Currents can be moved by tidal patterns. As the tides rise and fall, ocean currents will be moved. According to the National Oceanic and Atmospheric Administration, tides are caused by the gravitation between the Earth, the sun and the moon. This gravitational pull affects the Earth's oceans. Currents in the oceans will occur along the tides, forming tidal currents.
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The sun can contribute to the movement of an ocean current. The sun heats the atmosphere, resulting in the creation of winds. The sun can also develop thermohaline circulation. Thermohaline circulation is created when ocean waters become dense due to temperature and salinity variations of ocean waters. As ocean waters become dense due to cooling or salinity, ocean currents are created as water moves from areas of higher to lower density.
The Coriolis force can affect current movement due to the rotation of the Earth. Since the Earth doesn't remain stationary and is in constant rotation, air within the atmosphere is deflected. The movement of air has an effect on wind drag with ocean currents.
Current Movement & Climate
In the Southern Hemisphere, ocean currents will move left. In the Northern Hemisphere, ocean currents move to the right. Due to the movement of ocean currents, the Earth's regional climate can be affected by the ocean currents.