Burchard Leibniz Institute for Baltic Sea Research Warnemünde hansburchardiowarnemuendede Coastal Ocean Dynamics Forth course Wadden Sea Dynamics T ID: 307972
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Slide1
Hans
Burchard
Leibniz Institute for Baltic Sea Research Warnemündehans.burchard@io-warnemuende.de
Coastal Ocean DynamicsForth course: Wadden Sea Dynamics
Slide2
T
he
Wadden Seahttp://en.wikipedia.org/wiki/Wadden_SeaSlide3
www.rapid.ac.uk
Wadden
Sea … and … thermo-haline circulation?Slide4
Warming
Precipitation
Weak
tidal mixing: vertically stratified
Strong
tidal
mixing
:
horizontally
stratified
Land
Ocean
Downward
surface
buoyancy
flux
Estuarine
circulation
Sea
bed
RiverSlide5
Global
ocean:
Spatially inhomogeneous surface buoyancy fluxes plus internal mixing leads to global overturning circulation. Wadden Sea:Spatially homogenous surface buoyancy fluxes over sloping bathymetry plus tidal mixing should lead
to redidual overturning circulation. But does it really happen?Slide6
Locations of five automatic
monitoring poles in the
Wadden Sea of theGerman Bight, recordingtemperature and salinity,(and thus density).How can we approach this with observations ?Burchard et al. (JPO 2008)Slide7
Climatology
:
Salinity difference HW-NWBurchard et al. (JPO 2008)Slide8
Climatology
:
Temperature difference HW-LWBurchard et al. (JPO 2008)Slide9
Climatology
:
Density difference HW-LWBurchard et al. (JPO 2008)Slide10
Suspended matter
concentrations
are substantially increased in theWadden Sea of the German Bight, withouthaving significantsources at the coast.Why ?
Total suspended matter from MERIS/ENVISAT on August, 12, 2003. Sediment transportin the Wadden SeaSlide11
Conceptual
model
Burchard et al. (in prep.)Slide12
Width-
averaged
Wadden Sea modelBurchard et al. (in prep.)Slide13
Width-
averaged
Wadden Sea model: Net precipitationBurchard et al. (in prep.)Slide14
Width-
averaged
Wadden Sea model: no buoyancy fluxBurchard et al. (in prep.)Slide15
Width-
averaged
Wadden Sea model: Net evaporationBurchard et al. (in prep.)Slide16
Does this all happen in nature?
Ok, let’s go out to the
Wadden Sea and measure:Slide17
Campaign in Lister Deep (April 2008)
Becherer
et al. (GRL 2011)shoalsSlide18
Becherer
et al. (GRL 2011
), Purkiani et al. (in prep)Data and model results at S1Slide19
Data and model results
at
S2Purkiani et al. (in prep)Slide20
Potential energy anomaly
(amount if energy needed to homogenise water column)
Water column stabilityTidal phaseNear lateral shoals, stratification kicks in already during flood.Becherer et al. (GRL 2011)Slide21
Results of fully
baroclinic
3D model (100 m resolution)Purkiani et al. (in prep.)(S1)(S2)Slide22
Results of fully
baroclinic
3D model (100 m resolution)Purkiani et al. (in prep.)FloodEbbSlide23
Model approach
:
1. Simulating a closed Wadden Sea basin (Sylt-Rømø bight) with small freshwater-runoff and net precipitation. 2. Spin up model with variable and with constant density until periodic steady state.3. Then initialise both scenarios with const. SPM concentration.4. Quantify SPM content for control volume.Burchard et al. (JPO 2008)Slide24
Surface salinity at high and low
water
Burchard et al. (JPO 2008)Slide25
Total
water
and SPM volumeWith density differencesV / km3Burchard et al. (JPO 2008)Slide26
Total
water
and SPM volumeWithout density differencesV / km3Burchard et al. (JPO 2008)Slide27
Sea
level
rise & tidal flat growth (Danish Wadden Sea)Data and graphics from Morten Pejrup, Copenhagen University