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The ocean: The ocean: waves, surface & waves, surface &
density currents, El density currents, El Niño, upwellings & Niño, upwellings &
tidestides
OCEANSOCEANS
71% of Earth’s surface Affect
– Weather– Climate– Food supplies– Recreation– Global trade– Marine life
WAVEWAVE
transfers transfers ENERGY ENERGY through through space & space & mattermatter
WAVESWAVES Water molecules Water molecules
move up & downmove up & down (sitting in a boat (sitting in a boat
and the boat and the boat moves up and moves up and down)down)
Transfer energy Transfer energy through mediums through mediums (water)(water)
Surface movement of a particle of water
wavelengthwavelength Distance from crest to crest (meters)Distance from crest to crest (meters)
AmplitudeAmplitude Resting position to crest or troughResting position to crest or trough Measure of the Measure of the amount of energyamount of energy
Wave heightWave height Distance from crest to troughDistance from crest to trough Crest to ocean floorCrest to ocean floor
FrequencyFrequency The # of wavelengths in a The # of wavelengths in a
certain amount of timecertain amount of time Higher frequency= Higher frequency=
more energy more energy
Electromagnetic Electromagnetic spectrumspectrum
Example of wavesExample of waves Ocean surface wavesOcean surface waves
– propagate through water.propagate through water. Radio waves, microwaves, infrared rays, Radio waves, microwaves, infrared rays,
visible light, ultra violet rays, x-rays, and visible light, ultra violet rays, x-rays, and gamma rays (electromagnetic radiation)gamma rays (electromagnetic radiation)– Propagation is possible without a medium -Propagation is possible without a medium -
vacuum vacuum Sound — a mechanical wave Sound — a mechanical wave
– propagates through air, liquid or solids (not propagates through air, liquid or solids (not vacuum)vacuum)
Seismic waves in earthquakes (P, S and L Seismic waves in earthquakes (P, S and L or surface)or surface)
WAVES & SURFACE CURRENTSWAVES & SURFACE CURRENTS What we think of as What we think of as
Normal ocean waves Normal ocean waves driven by winddriven by wind
Are the same as Are the same as
SURFACE CURRENTSSURFACE CURRENTS DRIVEN BY THE WINDDRIVEN BY THE WIND
WindWind only only affectsaffects the the top top ~100m of water~100m of water
What Is a Wave?What Is a Wave?Most waves form when winds blowing Most waves form when winds blowing across the water’s surface transmit their across the water’s surface transmit their energy to the water.energy to the water.
How Waves Change Near How Waves Change Near ShoreShore
Near shore, wave height increases Near shore, wave height increases and wavelength decreases.and wavelength decreases.
Surface currentsSurface currents
Deep Ocean Currents Deep Ocean Currents (Global Conveyor Belt)(Global Conveyor Belt)
Driven by density differences in Driven by density differences in waterwater
Density: mass per volume Density: mass per volume (how (how compact it is)compact it is)– Bowling ball and beach ball the same Bowling ball and beach ball the same
sizesize– Which is denser? Which is denser? – Water: cold and salty = denserWater: cold and salty = denser
Deep CurrentsDeep Currents
Deep currents are Deep currents are caused by differences in caused by differences in the density of ocean the density of ocean water.water.
Deep Ocean Currents Deep Ocean Currents (DENSITY)(DENSITY)
1.1. Surface currents Surface currents warm water to warm water to poles:poles:
2.2. warm water cools; cold, denser and warm water cools; cold, denser and salty water sinkssalty water sinks
Creates a convection currentCreates a convection current
3. Deep currents carry cold water to 3. Deep currents carry cold water to equatorequator
4. Water warms 4. Water warms less dense and rises less dense and rises
Density current FACTS:Density current FACTS:
Deep ocean currents move more Deep ocean currents move more slowly than surface currentsslowly than surface currents– Couple cm/secondCouple cm/second– Surface currents: tens or hundreds of Surface currents: tens or hundreds of
cm/scm/s
Takes 1,000 years to complete circuitTakes 1,000 years to complete circuit
Deep Ocean Currents: Deep Ocean Currents:
Why is it important?Why is it important?Brings Brings nutrients to the nutrients to the
surfacesurfacehelps helps regulate global regulate global
temperaturestemperatures
UpwellingUpwelling winds pushes aside surface winds pushes aside surface
water water by blowing it away and by blowing it away and deeper deeper water rises up water rises up to replace itto replace it
Effects of UpwellingEffects of Upwelling Brings in Brings in
nutrients to nutrients to surfacesurface water water
enables enables ecosystems to ecosystems to flourishflourish and and some in unlikely some in unlikely places places ((AntarcticaAntarctica))
Photo courtesy NOAA
El NiñoEl Niño Unusually warm Unusually warm
ocean current along ocean current along the pacific coast of the pacific coast of South AmericaSouth America
Caused by weakening Caused by weakening in easterly windsin easterly winds
Impact: heavy Impact: heavy rains in some rains in some areas, droughts areas, droughts in othersin others
Sea surface temp in 2009-2010 Sea surface temp in 2009-2010
TIDESTIDES 2x a day change 2x a day change
in ocean levelin ocean level CAUSED BYCAUSED BY: :
gravitational gravitational pull pull of the moon of the moon and the sun on and the sun on the Earththe Earth
MOONMOON
Bay of FundyBay of Fundy
Bay of Fundy, Hopewell Bay of Fundy, Hopewell RocksRocks
Located Located between the between the Canadian Canadian provinces of provinces of New New Brunswick and Brunswick and Nova Scotia, Nova Scotia, Bay of Fundy Bay of Fundy features the features the world's world's highest, at highest, at 16.2 meters, 16.2 meters, and lowest and lowest tides.tides.
Hopewell Rocks @ high Hopewell Rocks @ high tidetide
Bay of Fundy- low & high Bay of Fundy- low & high tidetide
TsunamiTsunamiA A tsunamitsunami is usually is usually causedcaused by an by an earthquakeearthquake beneathbeneath the the oceanocean floorfloor..