OCEAN CURRENTSOCEAN CURRENTS

OCEAN CIRCULATIONOCEAN CIRCULATION

Of the four systems on earth, the hydrosphere is what separates us from the other planets.

Earth’s vast quantities of water make life as we know it possible

About 70% of Earth’s surface is covered in water - most of which is found in the oceans

Of the four systems on earth, the hydrosphere is what separates us from the other planets.

Earth’s vast quantities of water make life as we know it possible

About 70% of Earth’s surface is covered in water - most of which is found in the oceans

SURFACE CURRENTSSURFACE CURRENTS

The ocean is not still, like a pond - it moves in distinct patterns called currents.

Some currents flow nearer to the surfaceSurface Currents

These currents are driven by several different forces Solar radiation Wind patterns Coriolis effect

The ocean is not still, like a pond - it moves in distinct patterns called currents.

Some currents flow nearer to the surfaceSurface Currents

These currents are driven by several different forces Solar radiation Wind patterns Coriolis effect

SOLAR RADIATIONSOLAR RADIATION

As energy from the sun hits earth, it is dispersed unevenly across the latitudes

This uneven heating causes air to rise and fall over the surface of the earth in distinct patterns

As energy from the sun hits earth, it is dispersed unevenly across the latitudes

This uneven heating causes air to rise and fall over the surface of the earth in distinct patterns

SOLAR RADIATIONSOLAR RADIATION More direct

energy from the sun hits the equator.

This air warms up and rises and is deflected either eastward or westward due to the Coriolis effect

More direct energy from the sun hits the equator.

This air warms up and rises and is deflected either eastward or westward due to the Coriolis effect

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CORIOLIS EFFECTCORIOLIS EFFECT

The Coriolis Effect is an apparent deflection of an object moving in a rotational motion

The Coriolis Effect is an apparent deflection of an object moving in a rotational motion

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SURFACE CURRENTSSURFACE CURRENTS

The way in which the air moves across the surface of the earth, directly influences how surface ocean currents move

Ocean currents develop due to friction between ocean water and the winds that blow across the surface.

Ocean currents move in a pattern consistent with the pattern of winds that blow across the surface of the earth.

The way in which the air moves across the surface of the earth, directly influences how surface ocean currents move

Ocean currents develop due to friction between ocean water and the winds that blow across the surface.

Ocean currents move in a pattern consistent with the pattern of winds that blow across the surface of the earth.

Ocean Circulation

DEEP WATER CURRENTSDEEP WATER CURRENTS

Some currents flow from the bottom of the ocean upwards

Deep water currents These currents are caused mainly

by density driven forces and gravity

Some currents flow from the bottom of the ocean upwards

Deep water currents These currents are caused mainly

by density driven forces and gravity

DENSITYDENSITY Density is mass per unit volume (D=M/V) In Seawater density depends on two factors

Temperature of the water Volume Salinity of the water Mass

Changes in density cause water to rise and fall Less dense water rises More dense water falls

These changes are what drives deep water current

Density is mass per unit volume (D=M/V) In Seawater density depends on two factors

Temperature of the water Volume Salinity of the water Mass

Changes in density cause water to rise and fall Less dense water rises More dense water falls

These changes are what drives deep water current

SALINITYSALINITY An increase in

dissolved substances increases the density

Salinity tends to be highest at the poles and near the equator. Near the poles, water is

trapped in glaciers - increasing the amount of salt in the water

Near the equator, evaporation is high - increasing the amount of salt in the water

An increase in dissolved substances increases the density

Salinity tends to be highest at the poles and near the equator. Near the poles, water is

trapped in glaciers - increasing the amount of salt in the water

Near the equator, evaporation is high - increasing the amount of salt in the water

TEMPERATURETEMPERATURE

A decrease in temperature causes an increase in density - the molecules are moving slower and packed closer together Density is greatest in

polar regions - high salinity and low temperature

Temperature is the most important factor in density

A decrease in temperature causes an increase in density - the molecules are moving slower and packed closer together Density is greatest in

polar regions - high salinity and low temperature

Temperature is the most important factor in density

THERMOCLINETHERMOCLINE The layer of ocean

water between 330m - 1000m , where there is a rapid change of temperature with depth.

The thermocline is essentially non-existent in high latitudes (polar regions)

The layer of ocean water between 330m - 1000m , where there is a rapid change of temperature with depth.

The thermocline is essentially non-existent in high latitudes (polar regions)

DEEP OCEAN CURRENTSDEEP OCEAN CURRENTS

Density Currents Dense water sinks and slowly spreads

out across the bottom of the ocean Most deep ocean currents begin in

high latitudes (poles) where temperature is low and salinity is high.

As the water becomes dense, it sinks and spreads out over the floor of the ocean

Density Currents Dense water sinks and slowly spreads

out across the bottom of the ocean Most deep ocean currents begin in

high latitudes (poles) where temperature is low and salinity is high.

As the water becomes dense, it sinks and spreads out over the floor of the ocean

DEEP OCEAN CURRENTSDEEP OCEAN CURRENTS

Evaporation Deep water currents can also exist as a

result of evaporation Evaporation of surface waters increases

salinity and thus the density of the water.

This is evident in the Mediterranean Sea. A dense water mass forms on the

surface, sinks and flows into the Atlantic

Evaporation Deep water currents can also exist as a

result of evaporation Evaporation of surface waters increases

salinity and thus the density of the water.

This is evident in the Mediterranean Sea. A dense water mass forms on the

surface, sinks and flows into the Atlantic

CONVEYER BELTCONVEYER BELT

CLIMATECLIMATE

The conveyer belt system of currents moves around the globe, influencing global climate

The conveyer belt system of currents moves around the globe, influencing global climate

CLIMATECLIMATE Heat Transfer

Currents transfer heat as they move across the ocean

When currents from low-latitude regions move to higher regions, they move warmer water to cooler areas on earth.

Heat Transfer Currents transfer heat

as they move across the ocean

When currents from low-latitude regions move to higher regions, they move warmer water to cooler areas on earth.

Gulf StreamGulf Stream The Gulf Stream is a

warm water current that brings warm water from the equator up to the North Atlantic.

This allows regions in northwestern Europe, like Great Britian, to experience milder winters - despite their latitude

The Gulf Stream is a warm water current that brings warm water from the equator up to the North Atlantic.

This allows regions in northwestern Europe, like Great Britian, to experience milder winters - despite their latitude

CLIMATECLIMATE

Warm water currents tend to create milder climates in normally cooler regions - Great Britian

Warm water currents tend to create milder climates in normally cooler regions - Great Britian

Cool water currents tend to create cooler than normal climates - California coast is an example. - Polar currents bring cool waters which create cooler climates, including extensive fox and cool ocean waters.

Cool water currents tend to create cooler than normal climates - California coast is an example. - Polar currents bring cool waters which create cooler climates, including extensive fox and cool ocean waters.