Ocean/Atmosphere/Ocean/Atmosphere/Geosphere/BiosphereGeosphere/Biosphere

Atmospheric Circulation and ClimateAtmospheric Circulation and Climate

Coreolis ForceCoreolis Force

Horizontal Ocean CirculationHorizontal Ocean Circulation

Vertical Ocean CirculationVertical Ocean Circulation

Circulation and AnimalsCirculation and Animals

ENSOENSO

Solar EnergySolar EnergyOverall average Earth T: 15COverall average Earth T: 15C

Greenhouse gasses important to maintainGreenhouse gasses important to maintainLow light wavelengths (Visible light) to earthLow light wavelengths (Visible light) to earth

Earth re-radiates high wavelengths (heat; Earth re-radiates high wavelengths (heat; infrared)infrared)

Solar EnergySolar EnergyAngle of incidence effects how much E to particular Angle of incidence effects how much E to particular areaarea

(Ice ablation is also important in re-radiation)(Ice ablation is also important in re-radiation)

Solar radiation effects Solar radiation effects surface atmosphere circulation:surface atmosphere circulation:atmosphere convection cellsatmosphere convection cells--> surface trade winds--> surface trade winds

Coriolis ForceCoriolis ForceHypotheticalHypothetical

FrictionalFrictionalfrom Earth’s rotationfrom Earth’s rotation

N: clockwise (right) N: clockwise (right) S: counterclockwise S: counterclockwise

(left)(left)

Effects tradewinds, Effects tradewinds, and ocean currentsand ocean currents

Ocean Heat BudgetOcean Heat BudgetQ = fluxQ = fluxBasic equation: QBasic equation: Qinin - Q - Qoutout = net accumulation = net accumulation

If QIf Qinin > Q > Qoutout, accumulation, accumulationIf QIf Qinin < Q < Qoutout, loss, lossIf QIf Qinin = Q = Qoutout, balance, balance

Ocean heat:Ocean heat:(Q(Qsunsun + Q + Qcirccirc) - (Q) - (Qradrad + Q + Qevapevap + Q + Qcondcond) = Ocean heat) = Ocean heat

QQinin Q Qoutout

Currently: 53% evap, 41% radiation, 6% Currently: 53% evap, 41% radiation, 6% condensationcondensation

Variable proportion of QVariable proportion of Qoutout per geographic region per geographic region

Continent EffectsContinent EffectsHigher range of T changes over continentsHigher range of T changes over continents

Water is better insulator: holds onto heatWater is better insulator: holds onto heatWinter, midcontinent: high PWinter, midcontinent: high PSummer, midcontient: low PSummer, midcontient: low P

--> alters ocean influences on climate--> alters ocean influences on climate

Mountains disrupt atmospheric circulation patternsMountains disrupt atmospheric circulation patternsTibetan Plateau uplift and monsoonal circulationTibetan Plateau uplift and monsoonal circulation

Chain reaction:Chain reaction:Ocean + solar radiation effects --> convection cells Ocean + solar radiation effects --> convection cells

--> precipitation + continental effects --> precipitation + continental effects --> runoff, sediment--> runoff, sediment--> into ocean --> effects primary productivity--> into ocean --> effects primary productivity

Horizontal Ocean Horizontal Ocean CirculationCirculation

GyresGyres

Wind driven: frictionWind driven: friction

Trade winds from atmospheric convection cellsTrade winds from atmospheric convection cellsLead to equatorial currentsLead to equatorial currentswhich leads to western boundary currentswhich leads to western boundary currentswhich leads to eastern boundary currentswhich leads to eastern boundary currents

Equatorial + W boundary + E boundary = Subtropical GyreEquatorial + W boundary + E boundary = Subtropical Gyre

Subpolar gyres also exist, smallerSubpolar gyres also exist, smaller

Gulf StreamGulf StreamWestern boundary current

GyresGyres

Horizontal Ocean Horizontal Ocean CirculationCirculation

Eckman TransportEckman Transport

Wind driven: frictionWind driven: friction

Assumes ideal water conditionsAssumes ideal water conditions

Surface water: 3% wind velocitySurface water: 3% wind velocity

Bottom usually < 100mBottom usually < 100m

But…ideal conditions not realBut…ideal conditions not realOther currents, wind variation, boundaries, water layersOther currents, wind variation, boundaries, water layers

Geostrophic CurrentsGeostrophic CurrentsDifferences in pressure: Pressure Gradient Force (PGF)Differences in pressure: Pressure Gradient Force (PGF)FrictionlessFrictionlessWater “piles up” in hill Water “piles up” in hill (max 1m; very low slope,100’s kms)(max 1m; very low slope,100’s kms)Hi P uphill; water flows to lo PHi P uphill; water flows to lo PCoriolis force deflects flowCoriolis force deflects flowWhen Coriolis = PGF When Coriolis = PGF

--> Geostrophic Current--> Geostrophic CurrentWater circles “hill”Water circles “hill”

Effects upwelling: ENSO eventsEffects upwelling: ENSO events

coriolis force

lo P hi P

PLAN VIEW

PGF

geostrophicWind

PressureGradientForce

hiP loP

Vertical Circulation: Vertical Circulation: UpwellingUpwelling

UpwellingUpwellingCommon along continental margins Common along continental margins Currents moved away from area --> Currents moved away from area -->

upwellingupwellingSupports world’s fisheriesSupports world’s fisheriesSan Diego -- LA coastline and sharksSan Diego -- LA coastline and sharks

Vertical Circulation: Vertical Circulation: UpwellingUpwelling

Vertical Circulation: Vertical Circulation: DownwellingDownwelling

Wind pushes water onshore: water sinks, moves offshoreWind pushes water onshore: water sinks, moves offshore

Cold Deep CurrentsCold Deep Currents

Cold water sinksCold water sinksNorth Atlantic current, Antarctic Bottom

Waterhi O2, hi nutrients

Balanced by upwelling

Vertical CirculationVertical CirculationThermohaline Thermohaline

CirculationCirculationDensity-drivenDensity-driven

Density is affected by temperature, salinityDensity is affected by temperature, salinity

T effects > salinity effectsT effects > salinity effects

Denser water sinks; less dense water risesDenser water sinks; less dense water rises

“ “Conveyer Belt”Conveyer Belt”

““Conveyer Belt”Conveyer Belt”Residence time at depth: ~300yrs using C14Residence time at depth: ~300yrs using C14

on whole conveyer belt: estimated 1000yrson whole conveyer belt: estimated 1000yrs

Ocean Ocean circulation circulation

and Organismsand Organisms

Larval transportLarval transport

Adults: Adults: upwelling brings upwelling brings nutrientsnutrientscurrents are predictablecurrents are predictable

TransportTransportFood Food timing of spawningtiming of spawning

After 1997-1998 El Nino/La NinaGreen and blue in ocean is highphytoplankton bloom (artificial color)

Zooplankton amountsZooplankton amountsWarmer colors = more zooplanktonWarmer colors = more zooplanktonBlue hatch areas: sperm whale catches

Gyres

Conveyer BeltUpwelling

In upper Paleozoic times, In upper Paleozoic times, supercontinent Pangaea: one large supercontinent Pangaea: one large ocean: how would ocean currents, ocean: how would ocean currents, climate, effects on organisms be climate, effects on organisms be changed?changed?