Oceans in Motion The ocean is constantly in motion Driven by: –Winds –Currents –Coriolis Effect.
Oceans and Climate Changes. Ocean Currents Movement of water from one place to another.
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Transcript of Oceans and Climate Changes. Ocean Currents Movement of water from one place to another.
Oceans and Climate Changes
Ocean Currents
•Movement of water from one place to another
Surface Currents•Powered by wind
•Move upper few 100 meters of seawater
•Wind forms when air in an area of high pressure moves to an area of lower pressure
•Equator’s warm air is pushed up by denser, colder air
•The Pole’s cold air, sinks below less dense air
•Due to the movement of the earth, wind and currents DO NOT move in straight lines
•The Coriolis Effect – rotation of the Earth causes moving air and water to change direction–To the right north of the equator
–To the left south of the equator
Gulf Stream Current - Warm• Atlantic Ocean• Brings warm water
from the equator up North
• Keeps N. American East Coast Waters warm
• Keeps Iceland mild and ice-free all year
California Current - Cold
•Pacific Ocean•Brings waters
from North pole down South
•Keeps North American West Coast Cool
Density Currents
• More dense water sinks and pushes up less dense water
• This moves water around globe
What makes Water Dense?
• Cold Temperature
• High Salinity (amount of salt in water)
Cold, Salty Water
• When water freezes, salts are dissolved and left in unfrozen water – This makes unfrozen water VERY DENSE
• When frozen water melts, it is less dense• This causes a change in density and
movement of water…DENSITY CURRENTS
WHY IS THIS IMPORTANT?
It is important because…• If the ice caps where to melt, then
we would have a large amount of less dense water
• If salinity is reduced, then density currents would WEAKEN or STOP
•This would cause major CLIMATE SHIFTS–Change in climate–Change in weather
El Nino
•An occasional climatic event in which strong Pacific winds WEAKEN or REVERSE
Effects of El Nino
•Ocean temperatures near Peru HEAT UP.
•The position and strength of one of the jet streams may be altered, changing wind and precipitation patterns around the world.
•Africa and Australia may experience drought
La Nina
•The winds blowing across the Pacific are stronger than normal
