ocean currents purpose: to identify, describe and list factors that control ocean currents to...
TRANSCRIPT
Ocean Currents
Purpose: To identify, describe and list factors that control ocean
currentsTo explain how ocean
currents affect climate in San Diego and the world
Warm-up
Imagine you are stranded on a desert island in the North Pacific Ocean. You stuff a distress “help” message in a bottle and throw it in the ocean, hoping someone in San Diego will get it.
Is it possible someone in San Diego will find your message and send help? Explain your answer.
Thor Heyerdahl and crew of 5
Sailed across the South Pacific from South America in a handcrafted raft called the Kon-Tiki in 1947 and landed in Polynesia
Demonstrated it is possible to travel across the ocean using ocean currents and wind
Believed people from Peru rafted 3000 miles across the Pacific Ocean and settled the islands of Polynesia
Surface Currents
Are stream like movements of water at the ocean’s surface. They are caused by the prevailing winds
Circulate thousands of miles across entire oceans
Surface Currents are influenced by:
Global windsThe Coriolis EffectContinental deflections
Surface winds (purple arrows) create surface currents (red)
The Trade Winds move currents east to west along the Equator
The Westerlies move currents west to east in mid-latitudes
Ocean currents distribute heat throughout the depths of the
oceanhttp://topex-www.jpl.nasa.gov/overview/climate-water.html
The Coriolis Effect
Winds, ocean currents and moving objects appear to move in curved paths as the Earth rotates beneath
Coriolis Effect Demonstration:Northern Hemisphere
Draw 2 circles Rotate the paper
counterclockwise Prediction: Draw a straight
line from a to b. Describe the result
Draw a straight line from c to d. Describe the result
a
b
c
d
Coriolis Effect Demonstration:Southern Hemisphere
Draw 2 circles Rotate the paper
clockwise Prediction: Draw a straight
line from a to b. Describe the result
Draw a straight line from c to d. Describe the resultc
d
a
b
Continents cause surface currents to change directions
Surface currents affect climates of the world
The Gulf Stream brings warm water from the Equator to northern Europe
Warmer climates result in latitudes that are similar to Canada
Cold water from the north is carried southward by the California Current
The cold water current keeps the climate comfortable along the West Coast all year
El Nino:
is the change in the location of warm and cold surface water every 2-7 years
results in worldwide weather changes causes heavy rains and mudslides in
California and droughts in other regions
Normal weather patterns occur when warmer water is found in the western pacific near Asia
During El Nino, purple shows warmer water located near
America in the eastern pacific.
Weather patterns across the USA and the world are changed
During El Nino years, the Trade Winds weaken and do not move warm water across the Pacific
Storms develop in the middle of the Pacific bringing heavy winter rain to San Diego
During El Nino, normally wet regions experience drought and
wildfires
Other areas, like S. California experience intense wave
damage from storms
Roads are destroyed and cliffs are eroded by waves and
flooding
Homes are flooded. Diseases spread by contaminated water.
Accidents and injuries are greater with stormy weather
Dry riverbeds in Arizona flood, damaging homes in Arizona
Saturated hills slide, creating hazardous driving conditions
Mudslides in on steep slopes destroy homes.
Strong winds of El Nino knock down trees
Ocean pier in S. California
Buoys from San Diego’s Scripp’s Institute are stationed in the Pacific Ocean to monitor water temperature
and El Nino events
El Nino will be back
What do you know?A supertanker breaks apart off the coast of Japan.
Millions of gallons of crude oil spill into the ocean.
Prepare a news broadcast detailing how San
Diego’s beaches could be affected. Draw a map and use your notes to explain your answer.
San Diego