Message in a Message in a BottleBottle

A satellite journey A satellite journey through the Gulf Streamthrough the Gulf Stream

Overview of PresentationOverview of Presentation The historical message and importance of The historical message and importance of

the Gulf Streamthe Gulf Stream The path of the global surface currentsThe path of the global surface currents A look at the concepts of formation of ocean A look at the concepts of formation of ocean

gyres, and special features gyres, and special features Discussion of the formation, properties and Discussion of the formation, properties and

position of the eddiesposition of the eddies

The MessageThe Message Historical Historical

ImportanceImportance

Exploration and Exploration and Trade provided Trade provided navigational navigational knowledge of the knowledge of the North Atlantic North Atlantic GyreGyre

The MessageThe Message Historical Historical

ImportanceImportance

Ben Franklin’s Ben Franklin’s map of fastest map of fastest route across the route across the Atlantic based on Atlantic based on his voyage his voyage measurements of measurements of 1775 - 17851775 - 1785

The MessageThe Message Historical Historical

ImportanceImportance

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

The PathThe Path

Tracking Tracking the Floatersthe Floaters

Glass fishing floats, Glass fishing floats, sneakers and toys sneakers and toys become tools to become tools to measure currents measure currents

Carried across the Carried across the Pacific by the Pacific by the strong Kuroshio strong Kuroshio currentcurrent

The PathThe Path Global surface Global surface

currents are the currents are the result of wind driven result of wind driven forceforce

Moving water is Moving water is deflected like the air deflected like the air by the Coriolis by the Coriolis effecteffect

The denser water is The denser water is deflected more than deflected more than the above airthe above air

The PathThe Path Tracking the Tracking the

FloatersFloaters

Path of water is Path of water is influenced by global influenced by global wind bands – Trades wind bands – Trades and Westerliesand Westerlies

Friction slows the Friction slows the deflected water deflected water throughout a depth throughout a depth of about 150 metersof about 150 meters

The PathThe Path

Tracking Tracking the Floatersthe Floaters

Current path is Current path is also affected by also affected by landformslandforms

Gulf Stream turns Gulf Stream turns sharply to the sharply to the east off Cape east off Cape Hatteras, NCHatteras, NC

The PathThe Path Tracking Tracking

the Floatersthe Floaters

Drift bottles Drift bottles deployed in the deployed in the Gulf of Mexico Gulf of Mexico and the and the Caribbean have Caribbean have been followed by been followed by satellites satellites

Data explains Data explains current motioncurrent motion

YOTO OTO floatsfloats

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

Major Oceanic surface currentsMajor Oceanic surface currents

The UnderstandingThe UnderstandingSpecial Special featuresfeatures

Origins in the Origins in the Gulf of Mexico Gulf of Mexico and waters merge and waters merge with Caribbean with Caribbean currentscurrents

Travels around Travels around the Straits of the Straits of Florida parallel to Florida parallel to East coastEast coast

““There is a There is a river in the river in the ocean”… ocean”… Mathew Mathew

Maury, 1855Maury, 1855

The UnderstandingThe UnderstandingSpecial Special featuresfeatures

Carries heat Carries heat energy toward the energy toward the continent of continent of EuropeEurope

Some surface Some surface water becomes water becomes cooler, more cooler, more saline and sinks saline and sinks near Norwaynear Norway

The UnderstandingThe UnderstandingSpecial featuresSpecial features

Gulf Stream water Gulf Stream water temperatures are temperatures are substantially substantially warmer than the warmer than the waters to the Northwaters to the North

Act as a barrier Act as a barrier between Sargasso between Sargasso Sea and North Sea and North Labrador currentLabrador current

The UnderstandingThe Understanding Gulf stream Gulf stream

water water temperatures temperatures are significantly are significantly warmer down to warmer down to depths of 1000 depths of 1000 metersmeters

The UnderstandingThe Understanding Volume of water Volume of water

transported is transported is from 55 to 106 from 55 to 106 cubic meters per cubic meters per secondsecond

Current velocity Current velocity is dependent on is dependent on the width and the width and depth of currentdepth of current

The UnderstandingThe UnderstandingSpecial featuresSpecial features

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

The UnderstandingThe Understanding Differences in sea Differences in sea

height are seen height are seen with satellite with satellite altimetryaltimetry

Pockets of warm Pockets of warm or cold water may or cold water may be trappedbe trapped

The Science TwistThe Science TwistUnique meandersUnique meanders Gulf stream Gulf stream

energy is diverted energy is diverted by changes in by changes in speed speed

Eddies form -- Eddies form -- rotating pockets rotating pockets that spin off the that spin off the main streammain stream

The Science TwistThe Science TwistUnique Unique meandersmeanders

Warm- core Warm- core eddies are found eddies are found usually to the usually to the north of the north north of the north wall wall

Spin clockwiseSpin clockwise WCR = Warm WCR = Warm

core ringscore rings

The Science TwistThe Science TwistUnique meandersUnique meanders Cold- core eddies Cold- core eddies

are found to the are found to the south of the Gulf south of the Gulf StreamStream

Spin Spin counterclockwisecounterclockwise

Migrate into the Migrate into the Sargasso SeaSargasso Sea

The Science TwistThe Science TwistUnique meandersUnique meanders Warm water Warm water

expands and is expands and is noticed by a noticed by a bulge in the sea bulge in the sea surfacesurface

Cold water eddies Cold water eddies are detected by a are detected by a depressiondepression

The Science TwistThe Science Twist Mesoscale eddies Mesoscale eddies

are 50-100 km in are 50-100 km in diameterdiameter

WCR drift back WCR drift back into Gulf Streaminto Gulf Stream

Cold eddies may Cold eddies may last several yearslast several years

The Science TwistThe Science TwistUnique meandersUnique meanders In the Gulf of In the Gulf of

Mexico, eddies Mexico, eddies are studied for are studied for their influence on their influence on hurricanes hurricanes

Hurricane Opal Hurricane Opal and Bret were and Bret were fueled by WCR’sfueled by WCR’s

Message in a BottleMessage in a Bottle

Describe several factors that Describe several factors that determine the flow of the Gulf determine the flow of the Gulf Stream?Stream?

What is the direction of flow of the What is the direction of flow of the world’s major ocean currents?world’s major ocean currents?

What is the relationship between What is the relationship between heat transport and the eddies?heat transport and the eddies?