Climate and Ocean Currents

• Surface Current: Wind driven• Sub-surface current (deep ocean current): Density

driven

•Currents equalize global temperatures•Currents control climate•Currents provide nutrients to marine organisms

Open-Ocean Wind driven Surface Current

Ekman Effect

Ekman transport

Ekman layer

Ekman layer

The integrated water mass transport is at the right angle, 90 degree, to the wind direction, known as Ekman transport.

Ekman Spiral

Ocean Gyres

Geostrophic Currents

Equatorial Upwelling

Coastal Upwelling and Downwelling

Gulf Stream

Arctic Ocean

Westward intensification

Harald Sverdrup

Henry Stommel

Barents Sea

Arctic Ocean

Westward intensification

Oceanic eddies

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Land

Warm- and Cold-Core Rings

Ocean Circulation

OceanCurrentsAnd Climate August

February

Deep ocean circulation

Upper surface water increases its density either directly by cooling or indirectly when ice freezes out to eject salt, and thus, increasing the density of the remaining water.

heating

cooling

Greenland Sea

Labrador Sea

Wedell SeaRoss Sea

Mediterranean Sea

Norwegian Sea

Deep water formationa. North Atlantic Deep Water

(NADW) Source: Norwegian sea,

Greenland Sea Labrador Sea

b. Mediterranean Deep Water (MIW) Source: Mediterranean Sea

c. Antarctic Bottom Water (AABW) Sources: Margins of Antarctic continent, Wedell Sea, Ross Sea

d. Pacific Intermediate Water (PIW) Sources: Bering Sea

Schematic diagram of the global ocean circulation pathway known as ‘conveyer’ belt due to its northward transport at the ocean surface, and southward return flow in the abyss in the Atlantic. The ocean circulation system is a slow, 3-D pattern of flow involving the surface and deep oceans around the world.

NADW

AADW

Global Oceanic Conveyor Belt

Ocean Circulation