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Ocean Currents The steady flow of ocean water in a prevailing direction

The steady flow of ocean water in a prevailing direction

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Page 1: The steady flow of ocean water in a prevailing direction

Ocean CurrentsThe steady flow of ocean water in a prevailing direction

Page 2: The steady flow of ocean water in a prevailing direction

Ocean CurrentsDriven by several factors

TidesWindThermohaline circulation

Page 3: The steady flow of ocean water in a prevailing direction

Tidal CurrentsOccur with the rise and fall of the tides

Near the shoreBaysEstuaries

http://oceanservice.noaa.gov/

Page 4: The steady flow of ocean water in a prevailing direction

Coastal CurrentsDepend on

WindsWavesLand formations

Page 5: The steady flow of ocean water in a prevailing direction

Coastal CurrentsWinds that blow along the shoreline—longshore winds—affect waves

and, therefore, currentsLongshore currents are generated when a wave train reaches the coastline and

release bursts of energyMay form rip currents (not rip tides) - a localized current that flows away from

the shoreline toward the ocean

http://oceanservice.noaa.gov/

Page 6: The steady flow of ocean water in a prevailing direction

Surface CurrentsOccur on the open oceanDriven by a complex global wind system

Page 7: The steady flow of ocean water in a prevailing direction

Surface Currents – Coriolis EffectDue to Earth’s rotation

The Earth rotates faster at the Equator than it does at the poles Earth is wider at the Equator; point on the Equator

has farther to travel in a day

http://www.classzone.com/books/earth_science/terc/content/visualizations/es1904/es1904page01.cfm

http://www2.palomar.edu/users/pdeen/Animations/34_Coriolis.swf

Page 8: The steady flow of ocean water in a prevailing direction

Surface Currents – Coriolis EffectCirculating air or wind is deflected by the Coriolis Effect

http://oceanservice.noaa.gov/

Page 9: The steady flow of ocean water in a prevailing direction

Surface CurrentsGlobal winds drag on the water’s surface

Caused movement in the direction that the wind is blowingResults in the deflection of surface ocean currents to the right in the Northern

Hemisphere (in a clockwise spiral) and to the left in the Southern Hemisphere (in a counter-clockwise spiral)

Called gyres Occur north and south of the equator Not at the equator

Coriolis effect is not present