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Published byNeal Parsons Modified over 9 years ago
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An ocean current is any permanent or continuous, directed movement of ocean water that flows in one of the Earth's oceans. Ocean Currents
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2 major types Surface Driven by: Wind Speed: Fast mostly Depth: Approx. <100 m Deep Driven by: Differences in Density=m/v Speed: SLOW always Depth: >100 m
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Prevailing winds: Initial push Westerlies= west to east Trade winds= East to equator Caused by… Uneven heating Water near equator warms due to direct sunlight Transfers heat to poles by CONVECTION Major causes of ocean currents
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Coriolis Effect: deflection of moving objects North= Right (clockwise) South= Left (counter clockwise) Basin Shape: Coastline AKA the toilet bowl Major causes of ocean currents
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Ocean currents are the result of ALL of the following, except: A. prevailing wind belts B. the shape of the ocean basin C. Coriolis force D. shifting tectonic plates Review
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Boundary Current Warm Gulf Stream Brazil Kuroshio Agulhas E. Australia Cold/Cool Benguela Peru Canary Greenland & Labrador W. Australia
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Equatorial North South Circumpolar Antarctic Boundary Current
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Gyre: set of four or more currents ( Draw in on map) Gyre
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Major surface currents
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a)Which boundary currents influence US coast lines? Gulf Stream & California Review
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Sandy
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Irene
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Review The Coriolis effect causes which oceanic circulation pattern in the Northern hemisphere shown below:
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Vertical mixing of water Changes in water temperature Surface is warmer Thermohaline circulation deep ocean currents caused by: differences in density. Salinity Increase salt=more dense Temperature Decrease temperature= more dense
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Salinity INCREASES (salt concentration goes up) Evaporation Ice formation Decreases (salt concentration goes down) Fresh water goes in Rain Surface runoff Ice Melts
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On your map identify areas of high and low salinity
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Which of the following factors increases the density and salinity in oceans? A. river runoff into oceans B. precipitation over oceans C. icebergs melting into oceans D. evaporation of seawater Review
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Normal conditions: Wind direction: Dominated by the trade winds (East towards Equator) Current direction: (strong cold current towards equator) E. Pacific water temps : Cool Effects: N. America normal warm summer/cool winter Cooler water of South American coast Australia warmer water Ocean-Atmosphere Patterns
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El Nino Conditions: Wind direction: Trade winds are weak or reversed (West towards Equator) Current direction: (Weak towards equator) E. Pacific water temps : Warm Effects: N. America Warmer winters Floods in South America Droughts in Australia Ocean-Atmosphere Patterns
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la Nina conditions: Wind direction: VERY strong trade winds (East towards Equator) Current direction: (Strong cold towards equator) E. Pacific water temps : Very Cold Effects: MUCH Cooler water of South American coast Australia MUCH warmer water US colder than normal winters with much more snow! Ocean-Atmosphere Patterns
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