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2 OCEAN CURRENTS TODAY: –PATTERN OF OCEAN CURRENTS –EXPLANATION OF OCEAN CURRENTS DVD – Power Of the Planet (Oceans)

3 4 forces: > solar heating > surface winds > Coriolis effect > and land masses result in a clockwise circulation of water in the Northern hemisphere. This circulation is known as a GYRE.

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5 OCEAN CURRENTS IN THE NORTH ATLANTIC 0º Equator 90º Pole NORTH EQUATORIAL CURRENT GULF STREAM NORTH ATLANTIC DRIFT LABRADOR CURRENT CANARIES CURRENT NORTH ATLANTIC DRIFT 15 Warm Current Cold Current

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7 OCEAN CURRENTS ACTIVITIES: Complete the questions on ocean currents - handout

8 OCEAN CURRENTS PAST 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

9 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

10 EL NINO AND LA NINA: Hyperlink TASK: a.Read pages 16  19 b.Answer questions 1  3 and question 5 under the heading ‘Energy Transfer and Ocean Currents’ on page 38  39 ANIMATION: Hyperlink