Journal 1: How does the Coriolis effect influence the

wind?How do you think this would affect currents

in the ocean?

Journal 2: WED 1/11What role do currents play in transporting

heat? How do currents affect climate?

WEBSITE FOR WEBQUEST:http://www.oar.noaa.gov/k12/html/elnino2.html

Chapter 9Highways in the Sea

Causes of CurrentsWhat 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

GyresWhat 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

What is an eddie?Friction against water’s surface that causes

swirling currentsImportant because they can profoundly affect

local temperatures and water conditions. Commercial fishing vessels use eddies to

locate fishCan also influence the speed of a shipCan affect local climates by redistributing

heat

Western Boundary Currents& Eastern Boundary CurrentsHow 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

Upwelling vs. DownwellingWind-driven currents that flow vertically Upwelling: upward vertical current that

brings deep water to the surfaceDownwelling: 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

El Nino Southern Oscillation (ENSO)Buildup of warm water in the Central and

Eastern Equatorial PacificTremendously affects world weather

patternsEl 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

Normal Conditions in the PO

El Nino Conditions

El Nino Effect on weather, marine habitats, and human activityMost 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

La NinaPowerful upwellings bring deep cooler

waters to the surfaceThis 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

Ocean Conveyor BeltThe interconnected flow of currents that

redistribute heatEarth’s “air conditioner”Moderates the world’s climateOcean Conveyor Belt Animation:http://bcs.whfreeman.com/thelifewire/content/chp58/5802003.html

Examples of Instruments/Methods that scientists use to study currents1. Drogue: float that determines the drift of

currents2. Argo Float: float that transmits data to

satellites 3. Various Flow Meters: measure and record

current speed and direction (Eulerian study method)

4. Doppler Acoustic Current Meter: determines current direction and speed

5. Flotsam method: accidental opportunities to study currents; ships losing cargo that wash up on beaches and can improve computer models of currents

CFA: SO3b: Explain the influence of the Coriolis effect on winds, ocean currents, and on weather and climate.1. What is the difference between an upwelling

and downwelling?2. How does El Nino (ENSO) effect the Earth’s

climate and weather?3. What is an eddie? How does it effect Earth’s

climate?4. What forces are responsible for currents?

Explain.5. What is the Ocean Conveyor Belt?6. Use a Venn Diagram to differentiate

between western boundary and eastern boundary currents.