GLY150: INTRODUCTION TO OCEANOGRAPHY University of North Carolina Wilmington

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Lecture Outline

Ocean Circulation

I. Horizontal Circulation

• Wind-induced circulation
  • Ekman spiral & transport
• Geostrophic currents
  • Subtropical gyres
    • N. Atlantic
      • Gulf Stream
      • N. Atlantic Current
      • Canary Current
      • N. Equatorial Current
    • S. Atlantic
      • Brazil Current
      • West Wind Drift
      • Benguela Current
      • S. Equatorial Current
    • N. Pacific
      • Kuroshio
      • California
      • N. Equatorial
    • S. Pacific
      • E. Australian
      • West Wind Drift
      • Peru
      • S. Equatorial
    • Indian Ocean
      • Agulhas
      • West Wind Drift
      • W. Australian
      • S. Equatorial
  • Westward intensification/Western Boundary Currents
    • Gulf Stream
    • Kuroshio Current
    • Brazil Current
    • E. Australian
    • Agulhas

II. Vertical Circulation

• Wind-induced circulation
  • Open-ocean
    • Equatorial upwelling (divergence)
    • Broad-scale downwelling (convergence) in subtropical gyres
    • Arctic and Antarctic Convergence
      • Antarctic intermediate water
  • Coastal
    • Coastal upwelling & downwelling
      • Coast of S. America and Africa
• Thermohaline circulation
  • Density changes
    • Salinity changes most important in coastal waters
    • Temperature changes most important in open oceans
  • Lateral density distribution
    • Equatorial - low density
    • 30°N,S - intermediate density
    • 50-60°N,S - high density
    • Polar - greatest density
  • Vertical density distribution
    • Upper/deep water masses
    • Pycnocline
      • Thermocline
      • Halocline

III. Oceanic Conveyor Belt of Life

• Thermohaline circulation
  • Density structure of oceans
    • Cold deep water
      • North Atlantic Deep Water
        • Forms in Norwegian, Labrador Seas
        • High oxygen content
      • Antarctic Bottom Water
        • Forms in Weddell Sea
        • Densest ocean water
  • Worldwide Deep-Water Circulation
    • Deep water flow path
      • N. Atlantic - S. Atlantic - Indian - S. Pacific - N. Pacific
      • Becomes less oxygenated
      • Becomes more nutrient-rich
    • Return surface flow path
      • N. Pacific - Indian - S. Atlantic - N. Atlantic
      • Becomes more saline

Some helpful links relevant to these lectures:
Ocean currents
Primer on Ocean Currents
Gulf Stream Voyage
Thermohaline Circulation - Climatic Research Unit simulation

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