08 – randmeere des atlantischen ozeans · 2014. 6. 24. · 08 – randmeere des atlantischen...
TRANSCRIPT
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Regionale Ozeanographie
08 – Randmeere des Atlantischen Ozeans
Literatur:
Tomczak, M. and S.Godfrey (2002): Regional Oceanography: An Introduction.
Kostenloser download unterhttp://www.es.flinders.edu.au/~mattom/regoc/pdfversion.html Denmark Strait Currents
Mediterranean seas
Tomczak & Godfrey, 2005
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Arctic Mediterranean bathymetry
Tomczak & Godfrey, 2005
Arctic meteorology
Tomczak & Godfrey, 2005
3
Arctic surface circulation
Tomczak & Godfrey, 2005
Sea ice cover
Tomczak & Godfrey, 2005
4
Ice coverage
2006
2007L. Kaleschke
Spreading of Atlantic Water,cyclonic wind forcing
Freshwater input
Cooling
Circulation & forcing
5
Arctic hydrography
Tomczak & Godfrey, 2005
Arctic hydrography
Tomczak & Godfrey, 2005
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Arctic hydrography
Tomczak & Godfrey, 2005
Atlantic Water inflow
Hansen & Østerhus, 2000
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Atlantic Water in the Arctic
Tomczak & Godfrey, 2005
Background stratification
Prater, 2005
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Convection
θ S
σ
Rudels et al., 2000
Shelf slope convection
Dense water formation on shelvessinking down continental slopesentrainment of ambient water
Open ocean convection
Dense mixed layerpenetrative & non-penetrative plumes
entrainment of ambient watereddy formation
Marshall and Schott, 1999
Convection
Temp
Salz
Mixed layer deepening Air-sea fluxes
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Overflows
Hansen & Østerhus, 2000
Faroe Bank Channel overflow
Hansen & Østerhus, 2000
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Faroe Bank Channel overflow
Hansen & Østerhus, 2000
Denmark Strait overflow
Tomczak & Godfrey, 2005
Denmark Strait Currents
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Exchange across the GSR
PW
OV
AW
OV
Observed overflowtransports
DSO – Denmark StraitFBC – Faroe Bank
Channel
Temperature distribution
AW – Atlantic Water ~ 8 SvPW – Polar Water ~ 2 SvOV – Overflow Water ~ 6 Sv
FBC large scale mixing
Temp – Sal diagramme
WestCentralChannel
observations
AW
LSW
OW
OW Overflow WaterLSW Labrador Sea Water
AW Atlantic Water
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Faroe Bank Channel: Downstream flow
Eddy formation downstreamof channel’s exit, 3-5 d
Mixing at interface
Rotating table plume experimentstrong density contrast
Plume temperature in-situ
Diapycnal mixingrequires Kz ~10-2 m2/s
inflow
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Stirring through eddies
Rotating table plume experimentweak density contrast
time
Bottom temperature
cold
warm
cold
Mooring data in plume
Faroe Bank Channel: Downstream mixing
10,000 1,000 100 10−1
−0.5
0
0.5
1
1.5
2
2.5
3Faroe Bank Channel overflow plume
distance [km]
temperature DegCdepth metreskin. energy (cm/s)2
0
1000
2000
3000
100
300
500
700
sill Iceland
Ch. Gibbs FZ
Equator this study
• Strong vertical shear in the channel
• Cross circulation in the channel
• Stirring through eddies AH ~ 102 m2/s
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Overflow movie
Labrador Sea
Tomczak & Godfrey, 2005
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Great salinity anomaly
Prater, 2005
Labrador Sea convection
Prater, 2005
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Labrador Sea convection
Prater, 2005
Downstream flow
Vertical distribution of temperature at ~60°N
Polar outflowWarm Inflow
Labrador ScotlandDeep outflows
Deep flows
Shallow flows
McCartney, 1997
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Northern AMOCWind
Arctic Mediterranean presently providesabout 2/3 to NADW at a very stable pace
Antarctic intermediate water
Tomczak & Godfrey, 2005
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Antarctic Bottom Water
Prater, 2005
Antarctic bottom water
Tomczak & Godfrey, 2005
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Eurafrican Mediterranean
Tomczak & Godfrey, 2005
Surface circulation
Tomczak & Godfrey, 2005
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Salinity section
Tomczak & Godfrey, 2005
Hydrography
Tomczak & Godfrey, 2005
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Mediterranean outflow Water
Tomczak & Godfrey, 2005
Mediterranean eddies
Richardson et al. (2000)
Serra, 2004
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Mediterranean eddies
Tomczak & Godfrey, 2005
American Mediterranean Sea
Tomczak & Godfrey, 2005
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Water renewal
Tomczak & Godfrey, 2005
Surface circulation
Tomczak & Godfrey, 2005
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Atlantic overturning circulation
Tomczak & Godfrey, 2005
Ocean circulation (cartoon)
cooling heating coolingprecipitation evaporation precipitation
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South Atlantic
Tomczak & Godfrey, 2005
Averaging climatological data