{Ocean Currents

Which ocean current if found off the coast of North Carolina?

Is it a warm water current or a cold water current?

How does it affect our climate and our economy?

Current off our Coast

Surface currents are controlled by three factors: global winds, the Coriolis effect, and continental deflections.

• Global Winds Winds that blow across the Earth’s surface create surface currents in the ocean. Different winds cause currents to flow in different directions.

Global WInds

The Coriolis Effect is the apparent curving of moving objects from a straight path due to the Earth’s rotation.

Coriolis Effect

• Continental Defections When surface currents meet continents, the currents deflect, or change direction.

Deflections

Streamlike movements of ocean water located far below the surface are called deep currents. Deep currents are not controlled by wind.

Controlled by density (temperature/salinity)

Deep Currents

Deep Current Formation

Gulf Stream

California Current

Upwelling is the movement of deep, cold, and nutrient-rich water to the surface of the ocean.

Upwelling

The nutrients that are brought to the surface support the growth of plankton. Plankton support larger organisms, such as fish and seabirds.

Upwelling

• El Niño is a change in the water temperature in the Pacific Ocean that produces a warm current.

• Effects of El Niño El Niño alters weather patterns enough to cause disasters, including flash floods, mudslides, and droughts. El Niño also prevents upwelling off the coast of South America.

El Niño

To study El Niño, scientist use a network of buoys located along the equator. The buoys collect data about surface temperature, air temperature, currents, and wind.

Why is it important to study El Nino?

El Niño

• Most waves form as wind blows across the water’s surface and transfers energy to the water.

• As the energy moves through the water, so do the waves. But the water itself stays behind, rising and falling in circular movements.

Waves

Wave Speed

w a v e p e r i o d (s)

w a v e le n g t h (m)

= w a v e s p e e d (m/s)

Waves

Waves

Breaking Waves

Shore Currents When waves crash on the beach head-on, the water they moved through flows back to the ocean underneath new incoming waves.

Currents

• Longshore Currents are water currents that travel near and parallel to the shore line.

• Longshore currents form when waves hit the shore at an angle.

• Longshore currents transport most of the sediment in beach environments

Longshore Currents

Tsunamis are waves that form when a large volume of ocean water is suddenly moved up or down. This movement can be caused by underwater earthquakes, as shown below.

Tsunami

Tsunami