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Transcript of OC3230-Paduan images Copyright © McGraw Hill Chap 7-8: Distributions SPECIAL DATES: MPA meeting…6...
OC3230-PaduanOC3230-Paduan images Copyright © McGraw Hillimages Copyright © McGraw Hill
Chap 7-8: DistributionsChap 7-8: Distributions
SPECIAL DATES:SPECIAL DATES:
MPA meeting…6 JulMPA meeting…6 JulR/V Pt Sur Cruise…14 JulR/V Pt Sur Cruise…14 JulR/V Pt Sur Cruise…25 JulR/V Pt Sur Cruise…25 JulExam-1 (definite)...2 AugExam-1 (definite)...2 AugExam-2 (Tentative)…1 SepExam-2 (Tentative)…1 SepLabor Day Holiday...5 SepLabor Day Holiday...5 SepFinal Exam...19 SepFinal Exam...19 Sep
(Sp-226, 1300-1450)(Sp-226, 1300-1450)
EX 1EX 1
OC3230 Calendar, Summer 2005version 7 August 2005
S.D. tripS.D. trip
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Chap 7-8: DistributionsChap 7-8: Distributions
Distributions of propertiesDistributions of properties(“Taxonomy” of T-S)(“Taxonomy” of T-S)
T: 0-6 ˚CT: 0-6 ˚CS: 34-35 ‰S: 34-35 ‰
TTaveave: 3.5 ˚C: 3.5 ˚C
SSaveave: 34.7 ‰: 34.7 ‰
Mostly “zonal” but withMostly “zonal” but withimportant variationsimportant variations
Vert. Grad >> Horz. GradVert. Grad >> Horz. Grad
Presentation typesPresentation types::
Horizontal maps or Horizontal maps or plan views plan views (contours)(contours)
Vertical ProfilesVertical Profiles
Vertical Sections Vertical Sections (contours)(contours)
75% by75% byvolumevolume
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Chap 7-8: DistributionsChap 7-8: Distributions
““Summer”Summer”(N.H.)(N.H.)
““Winter”Winter”(N.H.)(N.H.)
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Chap 7-8: DistributionsChap 7-8: Distributions
Annual range is Annual range is maximum in mid maximum in mid latitudeslatitudes
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Chap 7-8: DistributionsChap 7-8: Distributions
T follows the sunT follows the sun
follows 1/Tfollows 1/T
S follows ?S follows ? ??
(Zonal) Sea Surface T, (Zonal) Sea Surface T, , S, S
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Chap 7-8: DistributionsChap 7-8: Distributions (Zonal) Sea Surface Salinity(Zonal) Sea Surface Salinity
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Chap 7-8: DistributionsChap 7-8: Distributions Sea Surface SalinitySea Surface Salinity
(cm)
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Chap 7-8: DistributionsChap 7-8: Distributions Sea Surface SalinitySea Surface Salinity
““Fresh”Fresh” ““Salty”Salty”
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Chap 7-8: DistributionsChap 7-8: Distributions TemperatureTemperature
SalinitySalinity
thermoclinethermocline
haloclinehalocline
ProfilesProfiles
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Chap 7-8: DistributionsChap 7-8: Distributions
ProfilesProfiles
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Chap 7-8: DistributionsChap 7-8: Distributions
pycnoclinepycnocline
DensityDensity
Note how curves join at depth:Note how curves join at depth:Deep water conditions are less variableDeep water conditions are less variableTop-to-bottom contrast is most extreme at the equatorTop-to-bottom contrast is most extreme at the equator
ProfilesProfiles
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Chap 7-8: DistributionsChap 7-8: Distributions
Seasonal cycle of upper Seasonal cycle of upper ocean temperature in mid ocean temperature in mid latitudeslatitudes
Note: different methods of Note: different methods of displaying the same datadisplaying the same data
50˚N, 145˚W50˚N, 145˚W(“Station P”)(“Station P”)
Profiles and ContoursProfiles and Contours
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Chap 7-8: DistributionsChap 7-8: Distributions Sections-TemperatureSections-Temperature
(Vertical) Temperature section through Atlantic Ocean(Vertical) Temperature section through Atlantic Ocean
Note bowl-shaped isothermsNote bowl-shaped isotherms
Note iso-thermal (constant temperature)Note iso-thermal (constant temperature)conditions at high latitudes, particularly in theconditions at high latitudes, particularly in thesouthern hemispheresouthern hemisphere
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Chap 7-8: DistributionsChap 7-8: Distributions Sections-TemperatureSections-Temperature
?? ??
Which profile Which profile comes from comes from which latitude?which latitude?
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Chap 7-8: DistributionsChap 7-8: Distributions Sections-TemperatureSections-Temperature
A review:A review:Which section is in situ temperature and which section isWhich section is in situ temperature and which section ispotential temperature, potential temperature, ? ?
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Chap 7-8: DistributionsChap 7-8: Distributions Sections-Temperature & SalinitySections-Temperature & Salinity
FreshFresh SaltySalty??
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Chap 7-8: DistributionsChap 7-8: Distributions Sections-Temperature & SalinitySections-Temperature & Salinity
version from text (note opposite view from west)version from text (note opposite view from west)
T (˚C)T (˚C)
S (‰)S (‰)
AtlanticAtlantic
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Chap 7-8: DistributionsChap 7-8: Distributions Sections-Temperature & SalinitySections-Temperature & Salinity
T (˚C)T (˚C)
S (‰)S (‰)
PacificPacific
S-minS-min S-minS-min
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Chap 7-8: DistributionsChap 7-8: Distributions Sections-Oxygen (ml/l)Sections-Oxygen (ml/l)
AtlanticAtlantic
PacificPacific
““Young”Young”
““Old”Old”
Surface values are ~8 ml/lSurface values are ~8 ml/l
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Chap 7-8: DistributionsChap 7-8: Distributions Sections-WOCE (80s-90s)Sections-WOCE (80s-90s)
The World Ocean Circulation The World Ocean Circulation Experiment (WOCE)Experiment (WOCE)
Decade-long, major international Decade-long, major international program to map T-S (and other) program to map T-S (and other) propertiesproperties
Section A-16 along 25W Longitude Section A-16 along 25W Longitude provides a good look at the water provides a good look at the water mass structure of the Atlantic Oceanmass structure of the Atlantic Ocean
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Chap 7-8: DistributionsChap 7-8: Distributions Sections-WOCE (80s-90s)Sections-WOCE (80s-90s)
Potential TemperaturePotential Temperature
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Chap 7-8: DistributionsChap 7-8: Distributions Sections-WOCE (80s-90s)Sections-WOCE (80s-90s)
SalinitySalinity
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Chap 7-8: DistributionsChap 7-8: Distributions Sections-WOCE (80s-90s)Sections-WOCE (80s-90s)
OxygenOxygen
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Chap 7-8: DistributionsChap 7-8: Distributions Other TracersOther Tracers
Known Source FunctionsKnown Source Functions OC DistributionsOC Distributions
Chlorofluorocarbons (e.g., Freon) and their ratiosChlorofluorocarbons (e.g., Freon) and their ratios
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Chap 7-8: DistributionsChap 7-8: Distributions Other TracersOther Tracers
Today’s CFC Today’s CFC distributions in the distributions in the Atlantic OceanAtlantic Ocean
Note the high values in Note the high values in the northeast surface the northeast surface waters consistent with a waters consistent with a deep-water source deep-water source regionregion
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Chap 7-8: DistributionsChap 7-8: Distributions Other TracersOther Tracers
Helium and “Bomb” Helium and “Bomb” carbon or heavy water carbon or heavy water (tritium)(tritium)
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Chap 7-8: DistributionsChap 7-8: Distributions Water MassesWater MassesWhat’s going What’s going on?on?
Interleaving Interleaving and mixing and mixing of “water of “water masses” masses” created near created near the surface the surface in particular in particular areasareas
Deepest Deepest layers layers originate originate from far N from far N and S in and S in AtlanticAtlantic
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Chap 7-8: DistributionsChap 7-8: Distributions Water MassesWater Masses
Step 1: SubductionStep 1: Subduction
Step 2: Mixing as water flows Step 2: Mixing as water flows along isopycnals…along isopycnals…
N-S surface gradientN-S surface gradient
verticalverticalgradientgradient
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Chap 7-8: DistributionsChap 7-8: Distributions Water MassesWater Masses
SS
TT
Water Type:Water Type:point on thepoint on theT-S diagramT-S diagramWater Mass:Water Mass:
line on theline on theT-S diagramT-S diagram
Water formed Water formed as a mixture of as a mixture of two water two water types must types must have T-S have T-S values that fall values that fall along the line along the line between the between the two original two original pointspoints
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Chap 7-8: DistributionsChap 7-8: Distributions Water MassesWater Masses
SS
TT
Water formed Water formed as a mixture of as a mixture of three water three water types must types must have T-S have T-S values that fall values that fall within the within the triangle be-triangle be-tween the tween the original pointsoriginal points
Water Type:Water Type:point on thepoint on theT-S diagramT-S diagram
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Chap 7-8: DistributionsChap 7-8: Distributions Water MassesWater Masses
TT SS T-ST-S
***Critical Figure******Critical Figure***
This illustrates This illustrates changes in the changes in the shape of profiles shape of profiles and T-S curves as and T-S curves as mixing occurs mixing occurs between distinct between distinct water typeswater types
The example The example mimics the low-mimics the low-salinity layer salinity layer observed at mid observed at mid depths in the depths in the AtlanticAtlantic
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Chap 7-8: DistributionsChap 7-8: Distributions Water MassesWater Masses
Thermohaline Circulation is Thermohaline Circulation is InferredInferred from fromT-S DistributionsT-S Distributions
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Chap 7-8: DistributionsChap 7-8: Distributions Water MassesWater Masses
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Chap 7-8: DistributionsChap 7-8: Distributions Water MassesWater Masses
SS
TT
***Critical******Critical***
Classic T-S Classic T-S curve curve observed in observed in the S. Atlantic the S. Atlantic OceanOcean
It provides It provides evidence of 4 evidence of 4 different different source water source water typestypes
AAIW: Antarctic Intermediate WaterAAIW: Antarctic Intermediate WaterNADW: North Atlantic Deep WaterNADW: North Atlantic Deep WaterAABW: Antarctic Bottom WaterAABW: Antarctic Bottom Water
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Chap 7-8: DistributionsChap 7-8: Distributions
SS
TT
Water Masses (< 4˚C)Water Masses (< 4˚C)
World OceanWorld Ocean
??
??
??
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Chap 7-8: DistributionsChap 7-8: Distributions
SS
TT
Water Masses (< 4˚C)Water Masses (< 4˚C)
World OceanWorld Ocean
IndianIndian
PacificPacific
AtlanticAtlantic
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Chap 7-8: DistributionsChap 7-8: Distributions Water MassesWater Masses
Deep water masses originate from the Southern Ocean Deep water masses originate from the Southern Ocean around Antarctica or from the north Atlantic Ocean.around Antarctica or from the north Atlantic Ocean.
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Chap 7-8: DistributionsChap 7-8: Distributions Water MassesWater Masses
Intermediate waters are dominated by AAIW, which Intermediate waters are dominated by AAIW, which originates along the subpolar front in the Southern Oceanoriginates along the subpolar front in the Southern Ocean
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Chap 7-8: DistributionsChap 7-8: Distributions Water MassesWater Masses
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Chap 7-8: DistributionsChap 7-8: Distributions Water MassesWater Masses
Value and depth of the Value and depth of the salinity minimum layers in salinity minimum layers in the Atlantic Oceanthe Atlantic Ocean
Evidence for northward Evidence for northward spreading of AAIW with a spreading of AAIW with a concentration of flow concentration of flow along the western along the western boundaryboundary AAIWAAIW
??
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Chap 7-8: DistributionsChap 7-8: Distributions Water MassesWater Masses
Surface water masses are many and have T-S Surface water masses are many and have T-S characteristics of the regioncharacteristics of the region
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Chap 7-8: DistributionsChap 7-8: Distributions Water MassesWater Masses
Mediterranean OutflowMediterranean Outflow
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Chap 7-8: DistributionsChap 7-8: Distributions Thermohaline “Conveyor Belt”Thermohaline “Conveyor Belt”
ThermohalineThermohalinecirculationcirculationinfluencesinfluencesand buffersand buffersthe climatethe climatesystemsystemthrough thethrough theslow circula-slow circula-tion of thetion of thedeep currentsdeep currentsand theand theexchange between surface and deep water that takes place exchange between surface and deep water that takes place over several thousand yearsover several thousand years
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Chap 7-8: DistributionsChap 7-8: Distributions Thermohaline “Conveyor Belt”Thermohaline “Conveyor Belt”
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Chap 7-8: DistributionsChap 7-8: Distributions Thermohaline “Conveyor Belt”Thermohaline “Conveyor Belt”
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Chap 7-8: DistributionsChap 7-8: Distributions O.T.E.C.O.T.E.C.
concept systemconcept system
closedclosedsystemsystem
openopensystemsystem