How do currents move?
Winds are able to move the top 400 meters of the ocean creating surface ocean currents. Surface ocean currents form large circular patterns called gyres. Gyres flow clockwise in Northern Hemisphere oceans and counterclockwise in Southern Hemisphere oceans because of the Coriolis Effect.
density current A current that is produced by differences in density. Where a flow of sea water has a greater density than that surrounding it, the denser water will dive beneath the less dense water. The density of sea water is affected by temperature, salinity, and the content of suspended sediment.
- The water at the ocean surface is moved primarily by winds that blow in certain patterns because of the Earth's spin and the Coriolis Effect. Winds are able to move the top 400 meters of the ocean creating surface ocean currents. Surface ocean currents form large circular patterns called gyres.
- The force, called the "Coriolis effect," causes the direction of winds and ocean currents to be deflected. In the Northern Hemisphere, wind and currents are deflected toward the right, in the Southern Hemisphere they are deflected to the left.
- There are two main factors that make ocean water more or less dense than about 1027 kg/m3: the temperature of the water and the salinity of the water. Ocean water gets more dense as temperature goes down. So, the colder the water, the more dense it is. Increasing salinity also increases the density of sea water.
Density currents in nature are exemplified by those currents that flow along the bottom of oceans or lakes. Such subaqueous currents occur because some of the water in an ocean or lake is colder or saltier or contains more suspended sediment and, thus, is denser than the surrounding waters.
- Some ocean currents are set in motion by the wind. Differences in the density of water can also cause currents to form and move. Density is affected by temperature and salinity. Cold water or water with dissolved salts (higher salinity) is denser than warm water or water without dissolved salts (low or no salinity).
- Why are density currents important to marine life in the deep ocean ? Retain the oxygen absorbed at the surface layer, as well as the temperature, salinity, and density. -This increases the salinity of water left behind. Upwelling can also be caused by density currents.
- Winds are able to move the top 400 meters of the ocean creating surface ocean currents. Surface ocean currents form large circular patterns called gyres. Gyres flow clockwise in Northern Hemisphere oceans and counterclockwise in Southern Hemisphere oceans because of the Coriolis Effect.
Ocean currents can be generated by wind, density differences in water masses caused by temperature and salinity variations, gravity, and events such as earthquakes. Currents are cohesive streams of seawater that circulate through the ocean.
- There are two type of Ocean Currents:
- Surface Currents--Surface Circulation.
- Deep Water Currents--Thermohaline Circulation.
- Primary Forces--start the water moving.
- The primary forces are:
- Secondary Forces--influence where the currents flow.
- Solar heating cause water to expand.
- Figure 14.14: The Coriolis Effect causes winds and currents to form circular patterns. The direction that they spin depend on the hemisphere that they are in. Currents on the surface are determined by three major factors: the major overall global wind patterns, the rotation of the Earth, and the shape of ocean basins.
- B. Surface currents are controlled by three factors: global winds, the Coriolis effect, and continental deflections. surface create surface currents in the ocean. Different winds cause currents to flow in different directions.
Updated: 9th October 2018