Ocean CurrentsOcean Currents

66thth Grade Earth Science Grade Earth Science

Sutton Middle SchoolSutton Middle School

Land has a lower specific heat!Land has a lower specific heat!

• Land heats up _______ than water, but it also cools Land heats up _______ than water, but it also cools off more __________.off more __________.

• Oceans heat _______, hold heat well, and give off Oceans heat _______, hold heat well, and give off heat slowly.heat slowly.– In winter, the ocean acts like a heater because it keeps the In winter, the ocean acts like a heater because it keeps the

coastal climate ___________coastal climate ___________– In summer, the ocean acts like an _______________as In summer, the ocean acts like an _______________as

cooler ocean air moves inland through convection currents.cooler ocean air moves inland through convection currents.– Land near the ocean is often _______ in winter and Land near the ocean is often _______ in winter and

cooler in the________.cooler in the________.

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Fill in the blanks!

Land has a lower specific heat!Land has a lower specific heat!

• Land heats up faster than water, but it also cools Land heats up faster than water, but it also cools off more quickly.off more quickly.

• Oceans heat slowly, hold heat well, and give off Oceans heat slowly, hold heat well, and give off heat slowly.heat slowly.– In winter, the ocean acts like a heater to faster cooling In winter, the ocean acts like a heater to faster cooling

land.land.– In summer, the ocean acts like an air conditioner as In summer, the ocean acts like an air conditioner as

cooler ocean air moves inland through convection cooler ocean air moves inland through convection currents.currents.

– Land near the ocean is often warmer in winter and Land near the ocean is often warmer in winter and cooler in summer.cooler in summer.

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Ocean CurrentsOcean Currents

•Mass movement or flow of Mass movement or flow of ocean waterocean water

•River within the oceanRiver within the ocean

•Two types Two types –Surface and DeepSurface and Deep

Surface CurrentsSurface Currents

Link•Horizontal, stream-like Horizontal, stream-like

movements of water that occur at movements of water that occur at or near the surface of the oceanor near the surface of the ocean

•Can reach depths of several Can reach depths of several hundred metershundred meters

•Example: GyresExample: Gyres

Surface CurrentsSurface Currents

•Controlled by three Controlled by three factorsfactors–Global windsGlobal winds–Coriolis EffectCoriolis Effect–Continental DeflectionsContinental Deflections

Surface CurrentsSurface Currents

•Global WindsGlobal Winds–Cause surface currents to flow in Cause surface currents to flow in

the direction the wind is blowingthe direction the wind is blowing–EX: Jet Stream EX: Jet Stream

•Coriolis Effect Coriolis Effect Link–The apparent curving of moving The apparent curving of moving

objects due to the Earth’s rotationobjects due to the Earth’s rotation

Surface CurrentsSurface Currents

•Coriolis Effect Coriolis Effect –Northern Hemisphere = clockwiseNorthern Hemisphere = clockwise–Southern Hemisphere = counter Southern Hemisphere = counter

clockwiseclockwise

•Continental DeflectionsContinental Deflections–Shape of continents change the Shape of continents change the

direction of current flowdirection of current flow

Deep CurrentsDeep Currents

•Stream like movement of ocean Stream like movement of ocean water far below the surfacewater far below the surface

•Caused by Caused by – Changes in densityChanges in density

–Change in temperatureChange in temperature–Change in salinityChange in salinity

What Effects Deep What Effects Deep Currents?Currents?

•Change in temperatureChange in temperature–Decreasing the temperature Decreasing the temperature of water increases densityof water increases density

•Change in salinityChange in salinity–Increasing the salinity of Increasing the salinity of water increases densitywater increases density

Currents and climateCurrents and climate

•Warm water currentsWarm water currents–Bring warm water to Bring warm water to colder regionscolder regions

Currents and climateCurrents and climate

•Cold water currentsCold water currents–Bring cold water to Bring cold water to warmer regionswarmer regions

Why are Ocean Currents Why are Ocean Currents Important?Important?• They make the average temperatures of climates more

similar

– This is on a large scale

• Ocean air holds a lot of water vapor – so there is more rain at the coast

• Currents redistribute heat throughout the globe– Example: Gulf Stream brings warm air into England,

making it warmer

Question 1Question 1

•What is a surface What is a surface current and what current and what causes them?causes them?

AnswerAnswer

•Surface currents move Surface currents move water horizontally – water horizontally – parallel to the Earth’s parallel to the Earth’s surfacesurface

•They are powered by windThey are powered by wind

Question 2Question 2

•What is the Coriolis What is the Coriolis Effect?Effect?

AnswerAnswer

•The Coriolis effect is The Coriolis effect is the shifting of winds the shifting of winds and surface currents and surface currents caused by Earth’s caused by Earth’s rotation.rotation.

Question 3Question 3

•What is upwelling?What is upwelling?

AnswerAnswer

•Upwelling is a vertical Upwelling is a vertical circulation in the circulation in the ocean that brings ocean that brings deep, cold water to deep, cold water to the ocean surface.the ocean surface.