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Journal 1:

Journal 1: . How does the Coriolis effect influence the wind? How do you think this would affect currents in the ocean?. Journal 2: WED 1/11. What role do currents play in transporting heat? How do currents affect climate? WEBSITE FOR WEBQUEST:

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Journal 1:

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  1. Journal 1: How does the Coriolis effect influence the wind? How do you think this would affect currents in the ocean?

  2. Journal 2: WED 1/11 • What role do currents play in transporting heat? How do currents affect climate? WEBSITE FOR WEBQUEST: http://www.oar.noaa.gov/k12/html/elnino2.html

  3. Chapter 9 Highways in the Sea

  4. Causes of Currents • What forces are responsible for currents? • Wind: transfers energy through friction on surface; causes currents and waves • Sea level: steeper slope=greater pressure gradient=drives a larger, faster current • Water density: greater density in one area causes pressure gradient to drive a current below the surface • What influences the direction and nature of these currents? • Ocean boundaries force currents in various directions; • Trade winds and the westerlies account for most of the wind’s energy that drives currents

  5. Gyres • What is a gyre? • Combo of the westerlies pushing water eastward, the trade winds pushing it westward, and the Coriolis effect resulting in the circular flow in each ocean basin • 5 major gyres

  6. What is an eddie? • Friction against water’s surface that causes swirling currents • Important because they can profoundly affect local temperatures and water conditions. • Commercial fishing vessels use eddies to locate fish • Can also influence the speed of a ship • Can affect local climates by redistributing heat

  7. Western Boundary Currents& Eastern Boundary Currents • How do Western Boundary Currents differ from Eastern Boundary Currents? • Eastern Currents: carry cool water towards equator; tend to be wide and shallow; not common to have eddies spin off these currents - Western Currents: much stronger; western intensification: Coriolis effect is a major contributor; there is weak flow of water toward the equator; flow of western boundary currents balances this slow drift; Trade winds also contribute to the strong western currents

  8. Upwelling vs. Downwelling • Wind-driven currents that flow vertically • Upwelling: upward vertical current that brings deep water to the surface • Downwelling: downward vertical current that pushes surface water deep into the ocean • What kind of biological effect does this have? -nutrients to shallow waters and to deeper waters -weather patterns

  9. El Nino Southern Oscillation (ENSO) • Buildup of warm water in the Central and Eastern Equatorial Pacific • Tremendously affects world weather patterns • El Niño= warm surface current in equatorial eastern Pacific that occurs periodically around Christmastime • Southern Oscillation= change in atmospheric pressure over Pacific Ocean accompanying El Niño • ENSO describes a combined oceanic-atmospheric disturbance

  10. Normal Conditions in the PO

  11. El Nino Conditions

  12. El Nino Effect on weather, marine habitats, and human activity • Most severe events of ENSO caused flooding, tornados, drought; 23,000 deaths and $33 billion in damages • Ruins kelp beds by warming the water b/c kelp only thrives in moderate to cold waters • This also affects local fish populations and other marine ecosystems

  13. La Nina • Powerful upwellings bring deep cooler waters to the surface • This colder than normal condition is called La Nina (opposite of El Nino) • Scientists still trying to determine what exactly causes these warm and cold phases

  14. Ocean Conveyor Belt • The interconnected flow of currents that redistribute heat • Earth’s “air conditioner” • Moderates the world’s climate Ocean Conveyor Belt Animation: http://bcs.whfreeman.com/thelifewire/content/chp58/5802003.html

  15. Examples of Instruments/Methods that scientists use to study currents • Drogue: float that determines the drift of currents • Argo Float: float that transmits data to satellites • Various Flow Meters: measure and record current speed and direction (Eulerian study method) • Doppler Acoustic Current Meter: determines current direction and speed • Flotsam method: accidental opportunities to study currents; ships losing cargo that wash up on beaches and can improve computer models of currents

  16. CFA: SO3b: Explain the influence of the Coriolis effect on winds, ocean currents, and on weather and climate. • What is the difference between an upwelling and downwelling? • How does El Nino (ENSO) effect the Earth’s climate and weather? • What is an eddie? How does it effect Earth’s climate? • What forces are responsible for currents? Explain. • What is the Ocean Conveyor Belt? • Use a Venn Diagram to differentiate between western boundary and eastern boundary currents.

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