CurrentsCurrents

CurrentsCurrents

Gulf Streamhttp://www.youtube.com/watch?v=UuGrBhK2c7U

http://gpb.pbslearningmedia.org/resource/ess05.sci.ess.watcyc.gulfstream/what-causes-the-gulf-stream/

Just Music, but good because shows Gulf Stream and the cold current sinking below. 30 secondshttp://www.youtube.com/watch?v=JDX5_ti3tcg

CurrentsCurrents

Finding Nemo…. And the Finding Nemo…. And the East Australian CurrentEast Australian Current

EAC in Finding Nemo (East Australian current)http://www.youtube.com/watch?v=I-N_7cgwHmQ

Exit EAC- Finding Nemohttp://www.youtube.com/watch?v=nof2FYyIeVg

Map of CurrentsMap of Currents

Map of CurrentsMap of Currents

What Causes Surface What Causes Surface Currents to Move?Currents to Move?

What force causes What force causes surface currents?surface currents?

How do surface How do surface currents affect currents affect climate on land?climate on land?

What force cause deep What force cause deep currents?currents?

What is El NiWhat is El Niñño?o?

What is a current?What is a current?

CurrentsCurrents are large are large streams of moving streams of moving

water that flow water that flow through the oceans.through the oceans.

They can move water They can move water and objects across the and objects across the

ocean.ocean.

Map of CurrentsMap of Currents

What causes currents?What causes currents?

•currents are caused by wind, the currents are caused by wind, the Earth's rotation, and differences Earth's rotation, and differences in water density within oceans.in water density within oceans.

What causes surface What causes surface currents?currents?

• Winds Winds are responsible for some ocean are responsible for some ocean currents.currents.

• A A surface currentsurface current is an ocean current that is an ocean current that moves along the top part of an ocean.moves along the top part of an ocean.

• Surface currents are moved by Surface currents are moved by prevailing prevailing windswinds and follow global wind patterns. and follow global wind patterns.

• Prevailing winds are winds that blow in Prevailing winds are winds that blow in regular directions almost all the time.regular directions almost all the time.

What determines the What determines the direction of surface direction of surface

currents?currents?• These winds and surface currents move These winds and surface currents move

in circular patterns in ocean basins.in circular patterns in ocean basins.

• Surface currents affect water to a depth Surface currents affect water to a depth of several hundred meters.of several hundred meters.

• Coriolis effect-Coriolis effect- the effect of Earth’s the effect of Earth’s rotation on the direction of winds and rotation on the direction of winds and currents. currents.

•Coriolis effect causes winds and currents Coriolis effect causes winds and currents to move in a curved path.to move in a curved path.

The Coriolis EffectThe Coriolis Effect

Current TemperaturesCurrent Temperatures• Surface currents can be cold or warm.Surface currents can be cold or warm.

• Those that flow from the poles toward the Those that flow from the poles toward the equator are cold.equator are cold.

• Those that flow from the equator towards Those that flow from the equator towards the poles are warm.the poles are warm.

How Surface Currents Affect How Surface Currents Affect ClimateClimate

• A A surface currentsurface current warms or cools the air warms or cools the air above it, influencing the climate of the land above it, influencing the climate of the land near the coast.near the coast.

• Currents affect climate by moving cold and Currents affect climate by moving cold and warm water around the globe.warm water around the globe.

• ClimateClimate is the pattern of temperature and is the pattern of temperature and precipitation typical of an area over a long precipitation typical of an area over a long period of time.period of time.

Gulf StreamGulf Stream

• The The Gulf Stream is a warm currentGulf Stream is a warm current that that flows northward up the east coast of the flows northward up the east coast of the United States toward Great Britain and United States toward Great Britain and western Europe.western Europe.

• This current causes the climate in Great This current causes the climate in Great Britain and western Europe to be warmer Britain and western Europe to be warmer than other places at the same latitude.than other places at the same latitude.

Gulf StreamGulf Stream

California CurrentCalifornia Current

• The California current is a surface current The California current is a surface current that carries cold water from the North that carries cold water from the North Pole, southward along California’s coast. Pole, southward along California’s coast.

• This current causes the climate in This current causes the climate in California to be cooler than it would be California to be cooler than it would be without the current. without the current.

What are deep What are deep ocean ocean currents?currents?

Deep currentsDeep currents are caused by differences in are caused by differences in density rather than surface winds.density rather than surface winds.

Density depends on temperature and salinity.Density depends on temperature and salinity.

The more salty and cold ocean water is the denser The more salty and cold ocean water is the denser it is. More dense water drops to the bottom of it is. More dense water drops to the bottom of the ocean and separates from less dense water, the ocean and separates from less dense water, and that movement creates a currentand that movement creates a current

Deep CurrentsDeep Currents

• Cold waters at the bottom of the Cold waters at the bottom of the ocean creep slowly across the ocean ocean creep slowly across the ocean floor.floor.

• Deep currents move and mix water Deep currents move and mix water around the world.around the world.

• They move much slower than surface They move much slower than surface currents.currents.

UpwellingUpwelling

• Upwelling is the upward movement of Upwelling is the upward movement of cold water from the ocean depths.cold water from the ocean depths.

• As wind blows away the warm surface As wind blows away the warm surface water, cold water rises to replace it.water, cold water rises to replace it.

• Upwelling brings up tiny ocean Upwelling brings up tiny ocean organisms, minerals, and other organisms, minerals, and other nutrients from the deeper layers of the nutrients from the deeper layers of the water. water.

El NiEl Niññoo• El NiEl Niññoo-- an abnormal an abnormal

climate event that climate event that occurs every 2 to 7 occurs every 2 to 7 years in the Pacific years in the Pacific Ocean.Ocean.

• This causes a sheet of This causes a sheet of warm water to move warm water to move eastward toward the eastward toward the South American coast.South American coast.

• El NiEl Niño can last for ño can last for one to two years one to two years before the usual winds before the usual winds and currents return.and currents return.

This damage in Southern California was the result of excessive rain caused by El Niño in 1997

El NiEl NiññooVideo of Regular Video of Regular Conditions, El Nino Conditions, El Nino conditions, and El Nina conditions, and El Nina conditions: conditions:

http://esminfo.prenhall.com/science/geoanimations/animations/26_NinoNina.html