Topic 10 - Surface Ocean Circulation [Lecture ppt | pdf]

Overheads (two lectures):

Driving Forces of Surface Ocean Circulation
Prevailing winds make waves and wind drift currents
Coriolis Force causes currents to deflect clockwise or counter-clockwise and develop Ekman spirals
Continental margins deflect and guide currents

Surface Ocean Currents and Upwelling
Boundary currents and offshore coastal winds create local coastal upwelling
Large-scale upwelling is associated with Equatorial Currents
Large-scale upwelling is associated with divergence of currents running past one another

Surface Currents in the Atlantic Ocean
North and South Equatorial Currents
Equatorial Countercurrent
Gulf Stream and Brazil Current
North Atlantic Current
Benguela Current and Canary Current
Sargasso Sea

Surface Currents in the Pacific Ocean
North and South Equatorial Currents
Multiple equatorial countercurrents
Kuroshio Current
North Pacific Current
California and Peru Currents
Equatorial and coastal upwelling

Surface Currents in the Indian Ocean
North and South Equatorial Currents
Equatorial Countercurrent
Somali and Agulhas Currents
Monsoonal effects on circulation

Surface Currents in the Antarctic
Antarctic Circumpolar Current - West Wind Current
East Wind Current
Boundary divergence and upwelling

The Gulf Stream
Western boundary current derived from equatorial currents
Warm, saline meandering current typically 100+ km in width,1 km in depth, with water speeds of 5 kph
Develops hot and cold rings as it flows
Cold coastal countercurrent
Carries warmth to North Atlantic and high salinity for NADW formation

California Current
Cold eastern boundary current derived from North Pacific Current
cools western USA margin - fog
Coastal upwelling associated with formation of Davidson Countercurrent
Davidson Countercurrent sinks and rises depending on degree of upwelling
Eddies form in California continental borderland as Current flows by


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