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Gulf Stream

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					Message in a Bottle
A satellite journey through the Gulf Stream

Overview of Presentation
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The historical message and importance of the Gulf Stream The path of the global surface currents A look at the concepts of formation of ocean gyres, and special features Discussion of the formation, properties and position of the eddies

The Message
Historical Importance
 Exploration

and Trade provided navigational knowledge of the North Atlantic Gyre

The Message
Historical Importance
 Ben

Franklin’s map of fastest route across the Atlantic based on his voyage measurements of 1775 - 1785

The Message
Historical Importance
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U.S. Coast and Geodetic Survey map (1890) showing the North Wall --the edge of this western boundary current

The Path
Tracking the Floaters
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Glass fishing floats, sneakers and toys become tools to measure currents Carried across the Pacific by the strong Kuroshio current

The Path
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Global surface currents are the result of wind driven force Moving water is deflected like the air by the Coriolis effect The denser water is deflected more than the above air

The Path
Tracking the Floaters
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Path of water is influenced by global wind bands – Trades and Westerlies Friction slows the deflected water throughout a depth of about 150 meters

The Path
Tracking the Floaters
path is also affected by landforms  Gulf Stream turns sharply to the east off Cape Hatteras, NC
 Current

The Path
Tracking the Floaters
 Drift

YOTO floats

bottles deployed in the Gulf of Mexico and the Caribbean have been followed by satellites  Data explains current motion

What does this drifter path tell you about the direction of the Gulf Stream?

Major Oceanic surface currents

The Understanding
Special features
is a river in the ocean”… Mathew Maury, 1855
“There
 Origins

in the Gulf of Mexico and waters merge with Caribbean currents  Travels around the Straits of Florida parallel to East coast

The Understanding
Special features
heat energy toward the continent of Europe  Some surface water becomes cooler, more saline and sinks near Norway
 Carries

The Understanding
Special features
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Gulf Stream water temperatures are substantially warmer than the waters to the North  Act as a barrier between Sargasso Sea and North Labrador current

The Understanding
 Gulf

stream water temperatures are significantly warmer down to depths of 1000 meters

The Understanding
 Volume

of water transported is from 55 to 106 cubic meters per second  Current velocity is dependent on the width and depth of current

The Understanding
Special features
 Geostrophic

balance exists in the N. Atlantic as the Coriolis effect piles water into a bulge ( Sargasso Sea) that gravity carries downhill

The Understanding
 Differences

in sea height are seen with satellite altimetry  Pockets of warm or cold water may be trapped

The Science Twist
Unique meanders
stream energy is diverted by changes in speed  Eddies form -rotating pockets that spin off the main stream
 Gulf

The Science Twist
Unique meanders
core eddies are found usually to the north of the north wall  Spin clockwise  WCR = Warm core rings
 Warm-

The Science Twist
Unique meanders
core eddies are found to the south of the Gulf Stream  Spin counterclockwise  Migrate into the Sargasso Sea
 Cold-

The Science Twist
Unique meanders
water expands and is noticed by a bulge in the sea surface  Cold water eddies are detected by a depression
 Warm

The Science Twist
 Mesoscale

eddies are 50-100 km in diameter  WCR drift back into Gulf Stream  Cold eddies may last several years

The Science Twist
Unique meanders
the Gulf of Mexico, eddies are studied for their influence on hurricanes  Hurricane Opal and Bret were fueled by WCR’s
 In

Message in a Bottle
 Describe

several factors that determine the flow of the Gulf Stream?  What is the direction of flow of the world’s major ocean currents?  What is the relationship between heat transport and the eddies?


				
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posted:4/16/2008
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