CURRENTS

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CURRENTS
Hey, Little Dude
WARM UP Friday 2/6 What effect does El Nino
have on the weather?
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What are ocean currents?

• Currents are a river of water within the ocean.
• There are two types of currents
• 1. Surface Currents
• 2. Deep Currents

Hey, Little Dude
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Currents
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Surface Currents
Surface Currents move horizontally!!

• Ex. Gulf stream
• Several hundred meters deep
• Surface currents can effect climate by warming or
  cooling the air above it.

http//www.classzone.com/books/earth_science/terc/
content/visualizations/es2401/es2401page01.cfm?cha
pter_novisualization
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Surface Currents

• Controlled by
• The Coriolis Effect
• The curving movement of water
• due to Earths rotation
• 2. The Global Winds
• Currents on the oceans surface
• due to blowing winds
• 3. Continental Deflections
• Water hits a continent and
• changes direction

CORIOLIS EFFECT
CONTINENTAL DEFLECTION
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SURFACE CURRENTS
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Formation
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Deep Currents
Deep currents move vertically!!

• Caused by differences in water density
• Cold water rises as it is heated, warm water
  sinks as it cools
• Salty water sinks, less salty water rises

Warm Water and Less Salty Water
Cold Water and More Salty Water
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DEEP CURRENT EXAMPLES

• EXAMPLE Antarctica Current
• Surface freezes ? salt remains in water
• increase salinity and density ? Water sinks
• Up to 500 years just to move
• along ocean bottom to
• the Equator

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Currents and Climate

• Surface currents warm or cool the coastline
• temperatures. Examples

THE GULF STREAM WARMS THE EAST COAST THE
CALIFORNIA CURRENT COOLS THE WEST COAST
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Upwellings

• Upwelling the movement of deep, cold, and
  nutrient-rich water to the surface
• Caused by local winds
• Brings nutrients to the surface from the deep
  water that supports plants and animals.

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El Nino

• Occurs every 2-12 years
• South Pacific Trade winds move less warm water to
  the western Pacific.
• Water temperatures rise and move west.
• Rise in water temperature changes climate
  patterns.

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El Nino