FLORIDA CURRENT, GULF STREAM, ANDLABRADOR CURRENT

55

P. L. Richardson, Woods Hole OceanographicInstitution, Woods Hole, MA, USA

Copyright & 2001 Elsevier Ltd.

This article is reproduced from the 1st edition of Encyclopedia of Ocean

Sciences, volume 2, pp 1054–1064, & 2001, Elsevier Ltd.

Introduction

The swiftest oceanic currents in the North Atlanticare located near its western boundary along thecoasts of North and South America. The majorwestern boundary currents are (1) the Gulf Stream,which is the north-western part of the clockwiseflowing subtropical gyre located between 101Nand 501N (roughly); (2) the North Brazil Current,the western portion of the equatorial gyre locatedbetween the equator and 51N; (3) the LabradorCurrent, the western portion of the counter-clockwise-flowing subpolar gyre located between451N and 651N; and (4) a deep, swift current knownas the Deep Western Boundary Current, which flowssouthward along the whole western boundary of theNorth Atlantic from the Labrador Sea to the equatorat depths of around 1000–4000 m.

The swift western boundary currents are con-nected in the sense that a net flow of warmer upperocean water (0–1000 m very roughly) passes north-ward through the Atlantic to the farthest reaches ofthe North Atlantic where the water is converted tocolder, denser deep water that flows back southwardthrough the Atlantic. This meridional overturningcirculation, or thermohaline circulation as it is alsoknown, occurs in a vertical plane and is the focus ofmuch recent research that is resulting in new ideasabout how water, heat, and salt are transported byocean currents. The combination of northward flowof warm water and southward flow of cold watertransports large amounts of heat northward, which isimportant for North Atlantic weather and climate.

History

The Florida Current, the part of the Gulf Streamflowing off Florida, was described by Ponce de Leonin 1513 when his ships were frequently unable tostem the current as they sailed southward. The firstgood chart of the Gulf Stream was published in1769–1770 by Benjamin Franklin and Timothy Fol-ger, summarizing the Nantucket ship captain’s

4

knowledge gained in their pursuit of the sperm whalealong the edges of the Stream (Figure 1). By the earlynineteenth century the major circulation patterns atthe surface were charted and relatively well known.During that century, deep hydrographic and currentmeter measurements began to reveal aspects of thesubsurface Gulf Stream. The first detailed series ofhydrographic sections across the Stream were begunin the 1930s, which led to a much-improved de-scription of its water masses and circulation. DuringWorld War II the development of Loran improvednavigation and enabled scientists to identify andfollow Gulf Stream meanders for the first time.Shipboard surveys revealed how narrow, swift, andconvoluted the Gulf Stream was. Stimulated by thesenew observations, Henry Stommel in 1948 explainedthat the western intensification of wind-driven oceancurrents was related to the meridional variation ofthe Coriolis parameter. Ten years later, Stommelsuggested that cold, dense water formed in the NorthAtlantic in late winter does not flow southwardalong the seafloor in the mid-Atlantic but instead isconstrained to flow southward as a Deep WesternBoundary Current (DWBC). This prediction wassoon verified by tracking some of the first subsurfaceacoustic floats in the DWBC off South Carolina. Inthe 1960s and 1970s, deep floats, and moored cur-rent meters began to provide some details of thecomplicated velocity fields in the Gulf Stream andDWBC. Satellite infrared measurements of sea sur-face temperature provided much information aboutthe near-surface currents including temporal vari-ations and eddies. In the 1980s and 1990s, surfacedrifters, subsurface floats, moored current meters,satellite altimetry, and various kinds of profilers wereused to obtain long (few years) time series. Thesehave given us our present understanding of westernboundary currents, their transports, temporal vari-ations, and role in transporting mass, heat and salt.Models of ocean circulation are playing an import-ant role in helping to explore ocean processes and thedynamics that drive western boundary currents.

Generating Forces

Two main forces generate large-scale ocean currentsincluding western boundary currents. The first iswind stress, which generates the large-scale oceanicgyres like the clockwise-flowing subtropical gyre

Figure 1 The Franklin–Folger chart of the Gulf Stream printed circa 1769–1770. This was the first good chart of the Stream and

continues today to be a good summary of its mean speed, course, and width (assuming the charted width is the limit of the Stream’s

meanders). (See Richardson PL (1980) Benjamin Franklin and Timothy Folger’s first printed chart of the Gulf Stream. Science 207:

643–645.)

FLORIDA CURRENT, GULF STREAM, AND LABRADOR CURRENT 555

centered in the upper part of the Atlantic (upper1000 m roughly). The second is buoyancy forcing,which generates differences in water density bymeans of heating, cooling, precipitation, and evap-oration and causes the large-scale meridional over-turning circulation (MOC) – the northward flow ofwarmer less dense water and the southward flow ofcolder, denser water underneath. The rotation andspherical shape of the earth intensify currents alongthe western margins of ocean basins. The westwardintensification is a consequence of the meridionalpoleward increase in magnitude of the verticalcomponent of Earth’s rotation vector, the Coriolisparameter. The vertical component is important be-cause the oceans are stratified and much wider thanthey are deep.

In the Gulf Stream, the northward wind-drivengyre circulation and the northward-flowing upper

part of the buoyancy-forced MOC are in the samedirection and are additive. The relative amounts oftransport in the Gulf Stream due to wind forcing andbuoyancy forcing are thought to be roughly 2:1, al-though this subdivision is an oversimplification be-cause the forcing is complicated and the Gulf Streamis highly nonlinear. In the vicinity of the GuyanaCurrent (B101N) the upper layer MOC is counter toand seems to overpower the wind-driven tropicalgyre circulation, resulting in northward flow, wheresouthward flow would be expected from wind stresspatterns alone. Farther south in the North BrazilCurrent (0–51N), the western boundary part of theclockwise-flowing wind-driven equatorial gyre is inthe same direction as the MOC, and their transportsadd. Along the western boundary of the LabradorSea, the southward-flowing part of the subpolar gyre,the Labrador Current, is in the same direction as the

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Figure 2 (A) Schematic showing the transport of the upper

layer (temperatures greater than around 71C) North Atlantic

circulation (in Sverdrups,1 Sv¼ 106 m3 s�1). Transports in

squares denote sinking and those in hexagons denote

entrainment. Red lines show the upper layer flow of the

meridional overturning circulation. The blue boxes attached to

dashed lines indicate that significant cooling may occur. Solid

green lines characterize the subtropical gyre and recirculations

as well as the Newfoundland Basin Eddy. Dashed blue lines

indicate the addition of Mediterranean Water to the North Atlantic.

(B) Schematic circulation showing the transport in Sverdrups of

North Atlantic Deep Water (NADW). Green lines indicate

transports of NADW, dark blue lines and symbols denote

bottom water, and red lines upper layer replacement flows.

Light blue line indicates a separate mid-latitude path for lower

NADW. The square represents sinking, hexagons entrainment of

upper layer water, and triangles with dashed lines water mass

modification of Antarctic Bottom Water. (Reproduced from

Schmitz (1996).)

556 FLORIDA CURRENT, GULF STREAM, AND LABRADOR CURRENT

DWBC, resulting in a top–bottom southward-flow-ing western boundary current.

Gulf Stream System

The Gulf Stream System is an energetic system ofswift fluctuating currents, recirculations, and eddies.The swiftest surface currents of B5 knots or250 cm s�1 are located where the Stream is confinedbetween Florida and the Bahamas. In this region andsometimes farther downstream, the Stream is knownas the Florida Current. Off Florida, the Gulf Streamextends to the seafloor in depths of 700 m and alsofarther north along the Blake Plateau in depths of1000 m. Near Cape Hatteras, North Carolina(351N), the Stream leaves the western boundary andflows into deep water (4000–5000 m) as an eastwardjet (Figure 2). The Stream’s departure point from thecoast is thought to be determined by the large-scalewind stress pattern, interactions with the southward-flowing DWBC, and inertial effects. The Gulf Streamflows eastward near 401N toward the Grand Banksof Newfoundland, where part of the Stream dividesinto two main branches that continue eastward andpart returns westward in recirculating gyres locatednorth and south of the mean Gulf Stream axis.

The first branch, the North Atlantic Current, flowsnorthward along the eastern side of Grand Banks asa western boundary current reaching 501N, where itmeets the Labrador Current, turns more eastward,and crosses the mid-Atlantic Ridge. Part of this flowcirculates counterclockwise around the subpolar gyreand part enters the Nordic Seas. This latter parteventually returns to the Atlantic as cold, denseoverflows that merge with less dense intermediateand deep water in the Labrador Sea and flowsouthward as the DWBC.

The second branch of the Gulf Stream flows south-eastward from the region of the Grand Banks,crosses the mid-Atlantic Ridge, and flows eastwardnear 341N as the Azores Current. Water from thisand other more diffuse flows circulates clockwisearound the eastern side of the subtropical gyre andreturns westward to eventually reform into the GulfStream. A north-westward flow along the easternside of the Antilles Islands is known as the AntillesCurrent. It is predominantly a subsurface thermo-cline flow.

Water flowing in the Gulf Stream comes from boththe westward-flowing return current of the sub-tropical gyre and from the South Atlantic. Roughlyhalf of the transport of the Florida Current is SouthAtlantic water that has been advected through theGulf of Mexico and the Caribbean from the NorthBrazil Current.

Current Structure

The Gulf Stream is a semicontinuous, narrow(B100 km wide) current jet with fastest speeds of200–250 cm s�1 located at the surface decreasing toaround 20 cm s�1 near 1000 m depth (Figure 3). Themean velocity of the Stream extends to the seaflooreven in depths below 4000 m with a mean velocity ofa few centimeters per second. The deep flow field

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Figure 3 Downstream speed (positive) (cm s�1) of the Gulf

Stream at 681W measured with current meters. (Adapted from

Johns et al. (1995).)

FLORIDA CURRENT, GULF STREAM, AND LABRADOR CURRENT 557

under the Stream is complex and not just a simpledeep extension of the upper layer jet.

The Stream flows along the juncture of the warmwater in the Sargasso Sea located to the south andthe cold water in the Slope Water region to the north(Figure 4). The maximum temperature gradientacross the Stream is located near a depth of 500 mand amounts to around 101C. Maximum surfacetemperature gradients occur in late winter when theSlope Water is coolest and the Stream advects warmtropical water northward. This relatively warmwater is clearly visible in infrared images of theStream (Figure 5). The sea surface slopes downnorthward across the Gulf Stream by around 1 m dueto the different densities of water in the Sargasso Seaand Slope Water region. The surface slope has beenmeasured by satellite altimeters and used to map thepath and fluctuations of the Stream.

Variability

The Gulf Stream jet is unstable. It meanders northand south of its mean position forming convolutedpaths that seem to have a maximum amplitude ofaround 200 km near 551W (Figure 6). The most en-ergetic meanders propagate downstream with a per-iod of around 46 days and wavelength near 430 km.Frequently the edges of individual large meandersmerge and coherent pieces of the Stream separatefrom the main current in the form of large eddies orcurrent rings. Gulf Stream rings are typically 100–300 km in diameter. Those north of the Stream rotateclockwise and those south of the Stream rotate

counterclockwise. As rings form on one side of theStream, they trap in their centers, water from theopposite side of the Stream. Cold core rings are lo-cated to the south and warm core rings to the north.Once separate from the Stream, rings tend to trans-late westward at a few centimeters per second. Oftenthey coalesce with the Stream after lifetimes of sev-eral months to years. The formation of rings is anenergy sink for the swift Gulf Stream jet and also actsto decrease the mean temperature gradient across theStream.

Infrared images and other data show that the GulfStream region is filled with meanders, rings, andsmaller-scale current filaments and eddies that ap-pear to be interacting with each other (Figure 5). Thepicture of the Gulf Stream as a continuous current jetis probably an oversimplification. Often variousmeasurements of the Stream are combined andschematic pictures are drawn of its ‘mean’ charac-teristics. Although no such thing as a ‘mean’ occursin reality, the schematics are very useful for simpli-fying very complex phenomena and for showingconceptual models of the Stream. One of the firstsuch schematics by Franklin and Folger is shown inFigure 1.

The swift current speeds in the Gulf Stream incombination with its energetic meanders, rings, andother eddies result in very large temporal currentfluctuations and very high levels of eddy kinetic en-ergy (EKE) that coincide with the Gulf Stream be-tween 551W and 651W (Figure 7A). Roughly 2/3 ofthe EKE is a result of the meandering Stream. Peakvalues of EKE near the surface are over 2000 cm2

s�2. The region of high EKE extends down to the seafloor underneath the Stream where values are in ex-cess of 100 cm2 s�2, roughly 100 times larger thanvalues in the deep Sargasso Sea (Figure 7B). EKE is ameasure of how energetic time variations and eddiesare in the ocean; EKE is usually much larger than theenergy of the mean currents which suggests that ed-dies are important to ocean physics at least where thelargest values of EKE are found.

The Gulf Stream varies seasonally and inter-annually, but because of energetic eddy motions andthe required long time series, the low-frequencyvariability has only been documented in a very fewplaces. The amplitude of the seasonal variation of theFlorida Current transport is relatively small, around8% of the mean transport, with maximum flow oc-curring in July–August. There is little evidence forlonger-term variations in the Florida Current. Inter-annual variations in the wind patterns over theNorth Atlantic have been observed as well as vari-ations in hydrographic properties and amounts ofLabrador Sea Water formed. Present research is

Figure 4 Temperature (A) and salinity (B) sections across the Gulf Stream near 681W. (Adapted from Fuglister FC (1963) Gulf

Stream ’60. Progress in Oceanography 1: 265–373.)

558 FLORIDA CURRENT, GULF STREAM, AND LABRADOR CURRENT

investigating these climate variations of the oceanand atmosphere.

Transport

The volume transport of the Florida Current oramount of water flowing in it has been measured to be

around 30 Sv where 1 Sverdrup (Sv) ¼ 106 m3 s�1.This transport is around two thousand times the an-nual average transport of the Mississippi River into theGulf of Mexico. As the Stream flows northward, itstransport increases 5-fold to around 150 Sv locatedsouth of Nova Scotia. Most of the large transport isrecirculated westward in recirculating gyres located

Figure 5 Satellite infrared image showing sea surface temperature distribution. Warm water (orange-red) is advected northward in

the Gulf Stream. Meanders and eddies can be inferred from the convoluted temperature patterns. Image courtesy of O. Brown, R.

Evans and M. Carle, University of Miami, Rosenstiel School of Marine and Atmospheric Science.

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Figure 6 Schematic representation of the instantaneous path of the Gulf Stream and the distribution and movement of rings. Each

year approximately 22 warm core rings form north of the Gulf Stream and 35 cold core rings form south of the Stream. (Reproduced

from Richardson PL (1976) Gulf Stream rings. Oceanus 19(3): 65–68.)

FLORIDA CURRENT, GULF STREAM, AND LABRADOR CURRENT 559

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Figure 7 (A) Horizontal distribution of eddy kinetic energy

(EKE) in the North Atlantic based on a recent compilation of

surface drifter data. EKE is equal to 12ðu02 þ v 02Þ where u 0 and v 0

are velocity fluctuations from the mean velocity calculated by

grouping drifter velocities into small geographical bins. High

values of EKE (cm2 s�2) coinciding with the Gulf Stream are 10

times larger than background values in the Sargasso Sea.

(Courtesy of D. Fratantoni, WHOI.) (B) Vertical section of EKE

(cm2 s�2) across the Gulf Stream system and subtropical gyre

near 551W based on surface drifters, SOFAR floats at 700 m and

2000 m (dots) and current meters (triangles). High values of EKE

coincide with the mean Gulf Stream axis located near 401N

(roughly). (Adapted from Richardson PL (1983) A vertical section

of eddy kinetic energy through the Gulf Stream system. Journal of

Geophysical Research 88: 2705–2709.)

560 FLORIDA CURRENT, GULF STREAM, AND LABRADOR CURRENT

north and south of the Gulf Stream axis (Figure 8).The 150 Sv is much larger than that estimated for thesubtropical gyre from wind stress (B30–40 Sv) and thenet MOC (B15 Sv). Numerical models of the GulfStream suggest that the large increase in transport andthe recirculating gyres are at least partially generatedby the Stream’s energetic velocity fluctuations. Theregion of largest EKE coincides with the maximumtransport and recirculating gyres both in the ocean andin models. Inertial effects and buoyancy forcing arealso thought to contribute to the recirculating gyres.

The velocity and transport of the Stream can besubdivided into two parts, a vertically sheared orbaroclinic part consisting of fast speeds near thesurface decreasing to zero velocity at 1000 m, and aconstant or barotropic part without vertical shearthat extends to the sea floor underneath the Stream.The baroclinic part of the Stream remains nearlyconstant (B50 Sv) with respect to distance down-stream from Cape Hatteras, but the barotropic partmore than doubles, from around 50 Sv to 100 Sv,causing the large increase in transport. The lateralmeandering of the Stream and the north and southrecirculating gyres are also highly barotropic andextend to the seafloor.

Estimates of the transport of the North AtlanticCurrent east of Newfoundland are also as large as150 Sv. A recirculating gyre, known as the New-foundland Basin Eddy, is observed to the east of thiscurrent.

North Brazil Current

The North Brazil Current (NBC) is the major west-ern boundary current in the equatorial Atlantic. TheNBC is the northward-flowing western portion of theclockwise equatorial gyre that straddles the equator.Near 41N the mean transport of the NBC is around26 Sv, which includes 3–5 Sv of flow over the Bra-zilian shelf. Maximum near-surface velocities areover 100 cm s�1.

Large seasonal changes in near-equatorial currentsare forced by the annual meridional migration ofthe Intertropical Convergence Zone that marks theboundary of the north-east tradewinds located tothe north and the south-east trades to the south. Themeridional migration of the winds causes largeannual variations of wind stress over the tropicalAtlantic. During summer and fall most of the NBCturns offshore or retroflects near 61N and flowseastward between 5 to 101N in the North EquatorialCountercurrent. During July and August the trans-port of the NBC increases to 36 Sv; most ofthe transport lies above 300 m, but the northward

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Figure 8 Schematic circulation diagram showing average surface to bottom transport of the Gulf Stream, the northern and southern

recirculating gyres, and the DWBC. Each streamline represents approximately 15 Sv. Because of the vertical averaging, the DWBC

looks discontinuous in the region where it crosses under or through the Gulf Stream near Cape Hatteras. (Adapted from Hogg NG

(1992) On the transport of the Gulf Stream between Cape Hatteras and the Grand Banks. Deep-Sea Research 39: 1231–1246.)

FLORIDA CURRENT, GULF STREAM, AND LABRADOR CURRENT 561

current extends down to roughly 800 m and includesAntarctic Intermediate Water. In April and May thetransport decreases to 13 Sv and the NBC becomesweaker, more trapped to the coast, and more con-tinuous as a boundary current. At this time thecountercurrent also weakens.

Occasionally, 3–6 times per year, large 400-kmdiameter pieces of the retroflection pinch off in theform of clockwise-rotating current rings. NBC ringstranslate northward along the western boundary10–20 cm s�1 toward the Caribbean, where theycollide with the Antilles Islands. The northwardtransport carried by each ring is around 1 Sv. Duringfall–spring the western boundary current regionnorth of the retroflection is dominated by energeticrings.

Amazon River Water debouches into the Atlanticnear the equator, is entrained into the western side ofthe NBC, and is carried up the coast. Some AmazonWater is advected around the retroflection into thecountercurrent and some is caught in rings as theypinch off. Farther north near 101N the OrinocoRiver adds more fresh water to the north-westward-flowing currents.

The path of South Atlantic water toward theGulf Stream is complicated by the swift, fluctuating

currents. Some northward transport occurs inalongshore flows, some in NBC rings, and some byfirst flowing eastward in the countercurrent, thencounterclockwise in the tropical gyre, and thenwestward in the North Equatorial Current.

The South Atlantic Water and Gulf Stream re-circulation merge in the Caribbean. Water in theCaribbean Current is funneled between Yucatanand Cuba into the swift narrow (B100 km wide)Yucatan Current. The flow continues in the Gulf ofMexico as the Loop Current, and then exits throughthe Straits of Florida as the Florida Current. Roughlyonce per year a clockwise rotating current ring pin-ches off from the Loop Current in the Gulf ofMexico and translates westward to the westernboundary, where a weak western boundary current isobserved.

Labrador Current

The Labrador Current is formed by very cold�1.51Cwater from the Baffin Island Current and a branchof the West Greenland Current, which merge onthe western side of the Labrador Sea. The currentflows southward from Hudson Strait to the

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and Wright (1993).)

562 FLORIDA CURRENT, GULF STREAM, AND LABRADOR CURRENT

southern edge of the Grand Banks of Newfoundland(Figure 9). The Labrador Current consists of twoparts. The first B 11 Sv is located over the shelf andupper slope and is concentrated in a main branchover the shelf break. This part is highly baroclinicand is thought to be primarily buoyancy-driven byfresh water input from the north. The second part,the deep Labrador Current, lies farther seaward overthe lower continental slope, is more barotropic, andextends over the full water depth down to around2500 m. Below roughly 2000 m is Nordic Seasoverflow water, which also flows southward alongthe western boundary. The deep Labrador Current isthe western portion of the subpolar gyre, which has atransport of around 40 Sv.

Most of the Labrador Current water leaves theboundary near the Grand Banks, part entering anarrow northward-flowing recirculation and partflowing eastward in the subpolar gyre. Very sharphorizontal gradients in temperature and salinityoccur where cold, fresh Labrador Current Water isentrained into the edge of the North Atlantic Cur-rent. Some Labrador Current Water passes aroundthe Grand Banks and continues westward along theshelf and slope south of New England and north ofthe Gulf Stream (Figure 10).

Deep Western Boundary Current(DWBC)

The DWBC flows southward along the westernboundary from the Labrador Sea to the equator.Typical velocities are 10–20 cm s�1 and its width isaround 100–200 km. It is comprised of North At-lantic Deep Water that originates from very cold,dense Nordic Seas overflows and from less cold andless dense intermediate water formed convectively inthe Labrador Sea in late winter. The DWBC is con-tinuous in that distinctive water properties like thehigh freon content in the overflow water and inLabrador Sea Water have been tracked southward tothe equator as plumes lying adjacent to the bound-ary. However, the DWBC is discontinuous in that itis flanked by relatively narrow sub-basin-scale re-circulating counterflows that exchange water withthe DWBC and recirculate DWBC water backnorthward. The net southward transport of theDWBC is thought to be around 15 Sv, but themeasured southward transport is often two or threetimes that, the excess over 15 Sv being recirculatedlocally.

Near the Grand Banks of Newfoundland, part ofthe DWBC water leaves the boundary and divides

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the Slope Water region north of the Gulf Stream. Plotted values

are westward velocity in cm s�1. The region of the DWBC is

indicated schematically by light lines. (Adapted from Johns et al.

(1995).)

FLORIDA CURRENT, GULF STREAM, AND LABRADOR CURRENT 563

into a northward-flowing recirculation and theeastward-flowing subpolar gyre circulation. Theother part flows around the Grand Banks and west-ward inshore of the Gulf Stream. Between the GrandBanks and Cape Hatteras, the DWBC coincides withthe northern recirculating gyre (or Slope Water gyre),which also flows westward there (Figure 10). NearCape Hatteras the DWBC encounters the deep GulfStream. Most of the deeper part of the DWBC seemsto flow continuously south-westward underneath themean axis of the Stream, but most of the water in theupper part of the DWBC appears to be entrained intothe deep Gulf Stream and flows eastward. Some ofthis water recirculates in the northern recirculatinggyre, and some crosses the mean axis of the Stream,recirculates westward south of the Stream towardthe western boundary, and continues southward. Theformation of energetic Gulf Stream meanders andpinched-off current rings is probably an importantmechanism by which DWBC water passes across orthrough the mean axis of the Stream.

See also

Benguela Current. Brazil and Falklands (Malvinas)Currents. Mesoscale Eddies. Wind DrivenCirculation.

Further Reading

Bane JM Jr (1994) The Gulf Stream system: anobservational perspective. In: Majumdar SK, MillerEW, Forbes GS, Schmalz RF, and Panah AA (eds.) TheOceans: Physical-Chemical Dynamics and HumanImpact, pp. 99--107. Philadelphia, PA: ThePennsylvania Academy of Science.

Fofonoff NP (1981) The Gulf Stream system. In: WarrenBA and Wunsch C (eds.) Evolution of PhysicalOceanography, Scientific Surveys in Honor of HenryStommel, pp. 112--139. Cambridge, MA: MIT Press.

Fuglister FC (1960) Atlantic Ocean atlas of temperatureand salinity profiles and data from the InternationalGeophysical Year of 1957–1958. Woods HoleOceanographic Institution Atlas Series 1: 209 pp.

Hogg NG and Johns WE (1995) Western boundarycurrents. U.S. National Report to International Unionof Geodesy and Geophysics 1991–1994. Supplement toReviews of Geophysics, pp. 1311–1334.

Johns WE, Shay TJ, Bane JM, and Watts DR (1995) GulfStream structure, transport and recirculation near 68W.Journal of Geophysical Research 100: 817--838.

Krauss W (1996) The Warmwatersphere of the NorthAtlantic Ocean. Berlin: Gebruder Borntraeger.

Lazier JRN and Wright DG (1993) Annual velocityvariations in the Labrador Current. Journal of PhysicalOceanography 23: 659--678.

Lozier MS, Owens WB, and Curry RG (1995) Theclimatology of the North Atlantic. Progress inOceanography 36: 1--44.

Peterson RG, Stramma L, and Korturn G (1996) Earlyconcepts and charts of ocean circulation. Progress inOceanography 37: 1--15.

Reid JL (1994) On the total geostrophic circulation of theNorth Atlantic Ocean: flow patterns, tracers, andtransports. Progress in Oceanography 33: 1--92.

Robinson AR (ed.) (1983) Eddies in Marine Science.Berlin: Springer-Verlag.

Schmitz WJ Jr and McCartney MS (1993) On the NorthAtlantic circulation. Reviews of Geophysics 31: 29--49.

Schmitz WJ Jr. (1996) On the World Ocean Circulation,vol. I: Some Global Features/North AtlanticCirculation. Woods Hole Oceanographic InstitutionTechnical Report, WHOI-96-03, 141 pp.

Stommel H (1965) The Gulf Stream, A Physical andDynamical Description, 2nd edn. Berkeley, CA:University of California Press.

Worthington LB (1976) On the North Atlantic circulation.The Johns Hopkins Oceanographic Studies 6.Baltimore, MD: The Johns Hopkins University Press.