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OCEAN CURRENTS

TODAY:

– PATTERN OF OCEAN CURRENTS– EXPLANATION OF OCEAN CURRENTS

DVD – PowerOf the Planet

(Oceans)

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4 forces: solar heating surface winds Coriolis effect and land massesresult in a clockwise circulation of water in the Northern hemisphere.

This circulation is known as a GYRE.

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OCEAN CURRENTS IN THE NORTH ATLANTIC

0º Equator

90º Pole

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NORTH EQUATORIAL CURRENT

GULF STREAM

NORTH ATLANTIC DRIFT

LABRADOR CURRENT

CANARIES CURRENT

NORTH ATLANTIC DRIFT

1 5Warm Current

Cold Current

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OCEAN CURRENTS

ACTIVITIES:

Complete the questions on ocean currents - handout

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OCEAN CURRENTSPAST PAPER QUESTION – 2004

Explain how the ocean currents operate to maintain the energy balance in the Atlantic Ocean. (8 marks)Use named currents

• In the Northern Hemisphere a clockwise loop known as a gyre is formed

• Warm waters flow N from the Gulf of Mexico• GULF STREAM AND NORTH ATLANTIC DRIFT

• Cooler water flows S• CANARIES CURRENT

• Cold water also flows S from the Poles• LABRADOR CURRENT

• This movement of warm and cold water helps to maintain the energy balance. Water heated at the equator is less dense, rises and spreads

• At the equator the trade winds push surface water westwards• Land masses then deflect the currents N&S• The coriolis effect also deflects currents• Westerlies then push the currents eastwards• Cold water (is more dense) sinks at the poles and moves towards the

equator• A similar gyre operates in an anti-clockwise direction in the Southern

Hemisphere

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OCEAN CURRENTS

SUMMARY NOTE:

Like the atmosphere the world’s oceans also have an important role in redistributing energy around the globe.

Again energy is moved from areas of surplus to those of deficit

Warm currents transport warm water polewards – this occurs as warm water is less dense and spreads out from the equator (surface)

Cold currents take cold water to lower latitudes – this happens as colder

water is dense and sinks, moving towards the equator (depths)

The formation of loops called gyres occurs- These flow clockwise in the N Hemisphere- Anti-clockwise in the S Hemisphere

From the diagram you must learn the names and locations of the most

common warm and cold currents

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EL NINO AND LA NINA:

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TASK:

a. Read pages 16 19b. Answer questions 1 3 and question 5 under the heading

‘Energy Transfer and Ocean Currents’ on page 38 39

ANIMATION:

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