Download - 15[1].3 Lecture
Ocean Waves, Tides & Ocean Waves, Tides & CurrentsCurrents
Chapter 15.3Chapter 15.3
Goal 1Goal 1
Explain waves in terms of Explain waves in terms of energy movementenergy movement
versus versus molecule movementmolecule movement
Wave CharacteristicsWave Characteristics
http://en.wikipedia.org/wiki/Image:Elliptical_trajectory_on_ripples.pnghttp://en.wikipedia.org/wiki/Image:Elliptical_trajectory_on_ripples.png
• Energy movementEnergy movement
• CrestCrest
• TroughTrough
• HeightHeight
• LengthLength– Long = fastLong = fast
Wave movement animationWave movement animation
http://www.geo.wvu.edu/~donovan/geol101/animations/27.swf
• Note the direction of energy Note the direction of energy movement and the movement of movement and the movement of water moleculeswater molecules
• Wave heightWave height– Wind speedWind speed– Wind durationWind duration– Fetch (size of body of water) Fetch (size of body of water)
• Breaking wavesBreaking waves– Friction slows trough (bottom)Friction slows trough (bottom)– Crest (top) collapses forwardCrest (top) collapses forward
Goal 2Goal 2
Discuss how tides formDiscuss how tides form
• TidesTides– Varies by location, topographyVaries by location, topography– Gravitational and Centrifugal forcesGravitational and Centrifugal forces– Moon, SunMoon, Sun– EarthEarth
Bay of Fundy Tide VideoBay of Fundy Tide Video• http://www.gma.org/undersea_landscapes/Bay_of_Fundy/http://www.gma.org/undersea_landscapes/Bay_of_Fundy/
http://www.asf.ca/CommMedia/downld/mapna2.jpg
• Spring tideSpring tide– Full / new moon = highest high tideFull / new moon = highest high tide
• Neap tideNeap tide– First / last quarter = lowest high tideFirst / last quarter = lowest high tide
Spring and Neap TidesSpring and Neap Tides
• www.decaelo.com/moongarden/ephemerides.htmwww.decaelo.com/moongarden/ephemerides.htm
Goal 3Goal 3
Understand movement of Understand movement of water via ocean currentswater via ocean currents
• Ocean currentsOcean currents– Density currentsDensity currents
•Deep water / bottom currentsDeep water / bottom currents
Deep Ocean CurrentsDeep Ocean Currents
http://science.hq.nasa.gov/oceans/images/CONVEYOR.jpghttp://science.hq.nasa.gov/oceans/images/CONVEYOR.jpg
• Surface currentsSurface currents– Driven by global wind systemsDriven by global wind systems– PredictablePredictable
•Trade windsTrade winds
•Prevailing westerliesPrevailing westerlies
•Polar easterliesPolar easterlies
• GyresGyres– Continents deflect surface currentsContinents deflect surface currents– Circular motion & Coriolis forceCircular motion & Coriolis force– Northern Hemi = ClockwiseNorthern Hemi = Clockwise– Southern Hemi = CounterclockwiseSouthern Hemi = Counterclockwise
Major Ocean CurrentsMajor Ocean Currents
US Navy Oceanographic OfficeUS Navy Oceanographic Office
http://www.learner.org/jnorth/images/graphics/n-r/OceanCurrentsUSNOO.gifhttp://www.learner.org/jnorth/images/graphics/n-r/OceanCurrentsUSNOO.gif
• UpwellingUpwelling– Cold water deflects up continentsCold water deflects up continents– Pushed out by windsPushed out by winds– West coasts & trade windsWest coasts & trade winds– Nutrient rich = fishNutrient rich = fish