Currents Ocean Currents Ocean currents are a movement

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Currents

Currents

Ocean Currents Ocean currents are a movement of ocean water that follows a regular

Ocean Currents Ocean currents are a movement of ocean water that follows a regular pattern. There are two types of currents: surface currents and deep (density) currents.

Ocean Currents: Surface Currents �Surface currents move water horizontally – parallel to Earth’s surface

Ocean Currents: Surface Currents �Surface currents move water horizontally – parallel to Earth’s surface �Surface currents are powered by wind �The wind forces the ocean to move in huge, circular patterns

Four Factors that affect Surface Currents 1. Global Winds � Global Winds blow across

Four Factors that affect Surface Currents 1. Global Winds � Global Winds blow across the Earth’s surface � Winds blow water east to west at the equator � Winds blow water west to east closer to the poles

2. Coriolis Effect �The curving path of a moving object from an otherwise straight

2. Coriolis Effect �The curving path of a moving object from an otherwise straight path due to Earth’s position �Northern Hemisphere – currents turn clockwise �Southern Hemisphere – currents turn counter-clockwise

3. Continental Deflection �When surface currents meet continents, and the current is deflected (bounces

3. Continental Deflection �When surface currents meet continents, and the current is deflected (bounces back), and changes direction

4. Temperature Affects Surface Currents �Warm-water currents begin near the equator and carry warm

4. Temperature Affects Surface Currents �Warm-water currents begin near the equator and carry warm water to the other parts of the ocean �Cold-water currents begin closer to the poles and carry cool water to other parts of the ocean.

Surface Currents Notice again the Red arrows and the Blue arrows showing the movement

Surface Currents Notice again the Red arrows and the Blue arrows showing the movement of warm water and the movement of cold water. Warm wants to move where it is cold and cold wants to move where it is warm.

Deep (density) Currents �Deep currents are a stream like movement of ocean water far

Deep (density) Currents �Deep currents are a stream like movement of ocean water far below the surface. �Deep in the ocean, waters circulate not because of wind but because of density differences. �A density current forms when a mass of seawater becomes more dense than the surrounding water. �More dense seawater sinks beneath less dense seawater. �Density currents circulate ocean water slowly.

This is important Ocean depth increases Density increases Temperature decreases Density decreases Salinity increases

This is important Ocean depth increases Density increases Temperature decreases Density decreases Salinity increases Density increases Temperature decreases because cold water is more dense and sinks

Density Currents

Density Currents

How surface currents and deep currents interact • Surface currents carry warm water to

How surface currents and deep currents interact • Surface currents carry warm water to polar regions. • Warm water replaces cold water that sinks to the ocean floor. • Deep currents carry cold water along the ocean floor from polar regions. • Water from deep currents rises to replace water leaving surface currents.

Waves & Currents Video http: //studyjams. scholastic. com/stu dyjams/science/weather-andclimate/waves-and-currents. htm

Waves & Currents Video http: //studyjams. scholastic. com/stu dyjams/science/weather-andclimate/waves-and-currents. htm