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MAR 110 Lecture #27 Natural Hazards and the Oceans

Section #2 REVIEW

MAR 110 MAR 110 Natural Hazards & the OceanNatural Hazards & the Ocean

Examination #2 FormatExamination #2 Format

Friday November 16, 2007Friday November 16, 2007SciSci & Eng Bldg Room 228& Eng Bldg Room 228

PART 1 PART 1 -- Term/Definition MatchingTerm/Definition Matching (~ 30 points) (~ 30 points)

PART 2 PART 2 –– Multiple Choice Multiple Choice (~ 50 points) (~ 50 points)

PART 3 PART 3 –– Short Answers Short Answers (~20 points(~20 points))

TOTAL TOTAL SolarSolar EnergyEnergy

ININ

The Earth’s Overall Heat BudgetThe Earth’s Overall Heat Budget

TOTALTOTALInfrared Infrared EnergyEnergy

OUTOUT==

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UNBALANCED HEAT BUDGET!UNBALANCED HEAT BUDGET!

An Atmosphere/Ocean An Atmosphere/Ocean Partnership Partnership MovesMoves

Tropical Heat SurplusTropical Heat Surplus

to regions of to regions of

Polar Heat DeficitPolar Heat Deficit

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THERMOHALINE THERMOHALINE CIRCULATIONCIRCULATION

The Deep Ocean Overturning ModeThe Deep Ocean Overturning Mode

A TwoA Two--Layered Atlantic OceanLayered Atlantic Ocean

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Atlantic Ocean Atlantic Ocean Deep Western Boundary Current (DWBC)Deep Western Boundary Current (DWBC)

PolarPolar

SubtropicalSubtropical

Sinking ZoneSinking Zone

TheTheWindWind--DrivenDrivenOcean Gyre Ocean Gyre

ModeMode

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North AtlanticNorth AtlanticSubtropical Ocean Subtropical Ocean

BasinBasin

Subtropical Subtropical WindsWinds

NortheastNortheastwardward

SouthwestSouthwestwardward

NHNHSubtropicalSubtropical

Ocean BasinOcean Basin

Zonal Winds Zonal Winds & &

Ekman TransportEkman Transport

GeostrophicGeostrophicOceanOceanFlowFlow

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GEOSTROPHIC FLOWGEOSTROPHIC FLOW

LowLowPressurePressure

Pressure PGF Pressure PGF Gradient Gradient ForceForce

CF CoriolisCF CoriolisForceForce

PGFPGF = = CFCFGEOSTROPHIC FLOW GEOSTROPHIC FLOW -- Force BalanceForce Balance

HighHighPressurePressure

The Gulf StreamThe Gulf Stream

A Western A Western Boundary Current Boundary Current

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Global WindsGlobal Winds

Ocean Ocean CurrentsCurrents

ClimateClimate

TradeTrade

Gulf Stream & the Gulf Stream & the Deep Western Boundary CurrentDeep Western Boundary Current

off of Cape Hatterasoff of Cape Hatteras

The DWBCThe DWBC“hugs the “hugs the

continental continental slope all the slope all the way to the tip way to the tip

of South of South America” America”

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The GenerationThe Generationof a of a

Coastal Winter Coastal Winter StormStorm

“The Blizzard of “The Blizzard of 1978”1978”

HAZARD HAZARD -- Subtropical Ocean Storm Subtropical Ocean Storm Winter Nor’eastersWinter Nor’easters BLIZZARD of 1978BLIZZARD of 1978

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Hurricane & Typhoon DistributionHurricane & Typhoon Distribution

HAZARDHAZARD –– Tropical Ocean StormTropical Ocean StormHurricane of 1938Hurricane of 1938

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Polar Front & the Polar Front & the Pressure Gradient ForcePressure Gradient Force

HURRICANE STRUCTUREHURRICANE STRUCTURE

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Storm SurgeStorm Surge

Low Low PressurePressureoo XX

20 ft20 ft

HAZARDHAZARD -- Storm SurgeStorm Surge““Raises the Platform” Enabling Coastal Wave DestructionRaises the Platform” Enabling Coastal Wave Destruction

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STORMSTORM--GENERATED WAVESGENERATED WAVES

Progressive WavesProgressive Waves

Wave Energy Alternates Forms Wave Energy Alternates Forms -- as it “progresses”as it “progresses”..between ..between Potential Energy (PE) Potential Energy (PE) and and Kinetic Energy (KE)Kinetic Energy (KE)

PEPE KEKE KEKE

PEPE

PEPE

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Wave Principles ReviewWave Principles Review

Deep Deep WaterWavesWaterWavesSpeed Depends on Speed Depends on WavelengthWavelength -- LL

CCp p (ft/s) =(ft/s) = 2.26 2.26 √√ LL (ft)(ft)

Cg Cg == ½ Cp ½ Cp

Shallow Shallow WaterWavesWaterWavesSpeed Depends on Speed Depends on Water DepthWater Depth -- DD

Cg Cg == Cp Cp == √ √ gDgD = 5.67 √ D= 5.67 √ D

Cg Cg == CpCp

Wave Principles ReviewWave Principles Review

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The Chaos of Open Ocean WavesThe Chaos of Open Ocean Waves

The Superposition of WavesThe Superposition of Waves

….with many different characteristics…..….with many different characteristics…..

….generated in far….generated in far--away places…. away places….

HAZARD HAZARD –– Open Ocean WavesOpen Ocean Waves“Rogue” Waves“Rogue” Waves

60 ft60 ft

112 ft !112 ft !

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Deep Water Wave Propagation Deep Water Wave Propagation –– Pacific Ocean Pacific Ocean -- SummerSummer

STORM WAVESTORM WAVEGENERATIONGENERATION

ZONEZONE

“Waves of ALL“Waves of ALLWavelengths”Wavelengths”

WAVEWAVEPROPAGATIONPROPAGATION

ZONEZONE

“Longer Waves “Longer Waves OutraceOutrace

Shorter Waves ”Shorter Waves ”

The Shoaling of Shallow Water WavesThe Shoaling of Shallow Water Waves

The water is moving shoreward in the The water is moving shoreward in the surf zonesurf zone

surf zonesurf zone

Wave Wave CurrentsCurrentsErodeErodeSandSand

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HAZARDHAZARD –– WaveWave--Induced Rip CurrentsInduced Rip Currents

HAZARD HAZARD –– Coastal Ocean Storm WavesCoastal Ocean Storm WavesExtreme Coastal Erosion & DamageExtreme Coastal Erosion & Damage

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Wave RefractionWave RefractionEnergy ConcentrationEnergy Concentration

& & ErosionErosion

BEACH PROFILE SEASONAL EVOLUTIONBEACH PROFILE SEASONAL EVOLUTION

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Surf Zone Turbulence Surf Zone Turbulence SuspendsSuspends sand grainssand grainsWater moves sand grainsWater moves sand grains

Longshore “Drift”Longshore “Drift” & Sand Transport& Sand Transport

Standing Waves & SeichingStanding Waves & Seiching

ll

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Real Ocean TidesReal Ocean Tides –– Rotary Standing WavesRotary Standing Waves

HAZARD HAZARD –– Extreme TidesExtreme TidesRaises the Sea Level Platform Raises the Sea Level Platform -- Enabling Coastal Wave DestructionEnabling Coastal Wave Destruction

50 ft50 ftTidalTidalRange!Range!