Ocean Currents

Objective

Ocean currents are cause by unequal heating and differences in salinity. The currents distribute heat around the planet.

Surface Currents

Surface currents: Are usually caused by wind patterns & have a depth of several hundred meters(1000 feet). They can travel as fast as 100 Km per day.

Some surface currents are cold.Some surface currents are warm.

Temperature of the water depends on where the currents originate.

Deep CurrentsIn streams called currents. These streams or rivers flow deep in the ocean and can be thousands of miles long.

Density CurrentsCaused by differences in

temperature and salinity of ocean water.

Cold – Salty water goes down.

Warm – Not so salty water goes up.

Major ocean currents affect the US

The California Current:

Brings very cold and salty water down from Alaska.

The Gulf Stream (Florida) Current. Very warm water flows away from the equator at about 5 mile per hour.

Gibraltar Current:Forms where the Mediterranean Sea meets the Atlantic Ocean at the Straight of Gibraltar.This salty water is more dense so it is heavier and sinks.

                              

GyresContinents deflect ocean currents to the north

and south so that closed circular systems, called gyres develop.

Upwelling

The upward motion of ocean water. Upwelling waters originate from the bottom of the ocean and thus are cold.