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..