Ocean Surface Currents draft (Thanks to Turtle Haste for this activity) Background



Download 119.93 Kb.
Date conversion26.11.2017
Size119.93 Kb.
Ocean Surface Currents - DRAFT

(Thanks to Turtle Haste for this activity)

Background:

Surface current are wind generated circular rotations of water. These patterns, called gyres, develop their shape as a result of wind stresses. The Ekman Spiral causes a current to flow at an angle to the area’s prevailing winds. Surface currents are responsive to changes in seasons and move somewhat, which is most apparent in the Equatorial currents. Involving approximately 10% of all ocean water, currents are restricted to the top 400 meters of the water column. Transporting heat from the Equator towards the polar regions and moving colder water from the poles towards the Equator, wind-driven open-ocean surface currents move at speeds approximately 1/100th of the wind speed at 10 meters above the surface. Major ocean currents transport large volumes of water. For example, the Antarctic Circumpolar Current transports water at approximately 4 km per hour.


Many organizations follow the surface movement of the oceans. NOAA’s OSCAR program tracks the surface currents with satellite altimeters. NOAA and Atlantic Oceanographic and Meteorological Laboratory launch drifter buoys that are transported around the oceans. Classrooms can adopt and track a drifter buoy. Many people collect items that wash up onto the beach which have traveled through currents, called flotsam. Global armature networks look for flotsam and send out world wide alerts when new materials appear. Scientists interested in the movement of Arctic ice track how the Arctic Current moves have placed buoys and ships in the ice to observe how the current moves the ice over time.

Image from Windows to the Universe (http://www.windows.ucar.edu/tour/link=/earth/Water/images/surface_currents_lg_jpg_image.html)




Time requirements:

Prep- 20 minutes

Class time 45 minutes
Materials


Demo:

Clear glass container with water

Straw

1-2 small pieces of paper



Per student:

Colored pencils (red and blue)

Pencil

World map



Teacher:

Overhead of world map

List of currents



Directions:

  • With the world map, discuss how the atmosphere heats unequally. Discuss how the Coriolis Effect moves water.

  • Demonstrate: Ask a student to place the small paper pieces into the glass container and place it on the overhead. Use the straw to blow on one side of the container. Observe the movement of the pieces as a result. Ask students for observations. This is what happens in the ocean but on a much larger scale.

  • Provide each student with a copy of the world map. Ask students to identify the Equator. Make a legend on the side of the map- cold water will be represented by blue, warm by red.

  • Read current descriptions to students. As a group, decide where to place the current and how to represent the size and direction of the flow. Name the current.

  • Repeat with all currents.




Ocean & Name

Hemisphere

Location

Flow

Temperature

Characteristics

Atlantic

(N. Atlantic Drift)



Northern

Northern Basin

From Canada to Europe

Cooling

Slow, shallow & Wide

Atlantic

(Canary)


Northern

Eastern Basin

From Pole toward the Equator

Cold

Slow, Shallow & Wide

Atlantic

(Gulf Stream)



Northern

Western Basin

From Equator toward the Pole

Warm

Fast, Deep & Narrow

Atlantic

(N. Equatorial)



Northern

North of Equator

From Africa to S. America

Warming

Slow, Shallow & Wide

Atlantic

(Benguela)



Southern

Eastern Basin

From pole toward the equator

Cold

Slow, Shallow & Wide

Atlantic

(Antarctic Circumpolar)



Southern

Southern Basin

West to east around Antarctica

Cooling

Slow, largest volume current

Atlantic

(S. Equatorial)



Southern

South of Equator

From Africa to S. America

Warming

Slow, Shallow & Wide

Atlantic

(Brazil)


Southern

Western Basin

From Equator toward the pole

Warm

Fast, Deep & Narrow

Pacific

(Kuroshio)



Northern

Western Basin

From Equator toward the pole

Warm

Fast, Deep & Narrow

Pacific

(N. Pacific)



Northern

North Basin

From Asia to N. America

Cooling

Slow, Shallow & Wide

Pacific

(N. Equatorial)



Northern

North of Equator

From C. America to S.E Asia

Warming

Slow, Shallow & Wide

Pacific

(California)



Northern

Eastern Basin

From Pole towards the Equator

Cold

Slow, Shallow & Wide

Pacific

(Peru)


Southern

Eastern Basin

From Pole towards the Equator

Cold

Slow, Shallow & Wide

Pacific

(E. Australian)



Southern

Western Basin

From Equator towards the pole

Warm

Fast, Deep & Narrow

Pacific

(Antarctic Circumpolar)



Southern

Southern Basin

West to east around Antarctica

Cooling

Slow, largest volume current

Pacific

S. Equatorial)



Southern

South of Equator

From. S. America towards Australia

Warming

Slow, Shallow & Wide


Discussion:

  • What patterns do the currents make? Gyres. How does water at the poles moving toward the Equator different in each hemisphere? Northern Hemisphere it moves to the right, Southern Hemisphere it moves to the left.

  • What would happen if you dropped a whole truck of toy ducks into the water near the coast of Peru? Where would they eventually go? What currents would they travel through?

  • Predict what occurs in the northern Indian Ocean without the influence of cold polar water.

  • How does the geography of the land affect the direction of the wind and water? Why is the flow different between currents? Find and identify the largest current. Explain why this occurs. Currents flow fastest when a large volume of water is forced to flow through a narrow gap.


Adaptation:

  • Can be done with a large world map as a group.


Extensions:

  • Look up the Arctic currents and place them on the map. Who might depend on the seasonal ice movement?

  • Add smaller currents and research the names/origin

  • Research the rate of transport for each current

  • Look up the Great Sneaker spills. Join Beachcombers Alert (www.beachcombers.org).





The database is protected by copyright ©ininet.org 2016
send message

    Main page