Hans Burchard Leibniz Institute for Baltic Sea Research Warnemünde

1. Coastal Ocean Dynamics Forthcourse: Wadden SeaDynamics Hans Burchard Leibniz Institute for Baltic Sea Research Warnemünde hans.burchard@io-warnemuende.de

2. The WaddenSea http://en.wikipedia.org/wiki/Wadden_Sea

3. WaddenSea … and … thermo-halinecirculation? www.rapid.ac.uk

4. WarmingPrecipitation Land Ocean Downwardsurfacebuoyancyflux Seabed Weaktidalmixing: verticallystratified River Estuarinecirculation Strong tidalmixing: horizontallystratified

5. Global ocean: Spatiallyinhomogeneoussurfacebuoyancyfluxesplus internalmixingleadsto global overturningcirculation. WaddenSea: Spatiallyhomogenoussurfacebuoyancyfluxesoverslopingbathymetry plus tidalmixingshouldleadtoredidualoverturningcirculation. But doesitreally happen?

6. Howcanweapproachthis withobservations ? Locations of five automatic monitoring poles in the Wadden Sea of the German Bight, recording temperature and salinity, (and thus density). Burchard et al. (JPO 2008)

7. Climatology: Salinitydifference HW-NW Burchard et al. (JPO 2008)

8. Climatology: Temperaturedifference HW-LW Burchard et al. (JPO 2008)

9. Climatology: Densitydifference HW-LW Burchard et al. (JPO 2008)

10. Sediment transport in theWaddenSea Suspended matter concentrations are substantially increased in the Wadden Sea of the German Bight, without having significant sources at the coast. Why ? Total suspended matter from MERIS/ENVISAT on August, 12, 2003.

11. Conceptual model Burchard et al. (in prep.)

12. Width-averagedWaddenSea model Burchard et al. (in prep.)

13. Width-averagedWaddenSea model: Net precipitation Burchard et al. (in prep.)

14. Width-averagedWaddenSea model: nobuoyancyflux Burchard et al. (in prep.)

15. Width-averagedWaddenSea model: Net evaporation Burchard et al. (in prep.)

16. Does this all happen in nature? Ok, let’s go out to the Wadden Sea and measure:

17. Campaign in Lister Deep (April 2008) shoals Becherer et al. (GRL 2011)

18. Data and model results at S1 Becherer et al. (GRL 2011), Purkiani et al. (in prep)

19. Data and model results at S2 Purkiani et al. (in prep)

20. Potential energy anomaly (amount if energy needed to homogenise water column) Water column stability Tidal phase Near lateral shoals, stratification kicks in already during flood. Becherer et al. (GRL 2011)

21. Results of fully baroclinic 3D model (100 m resolution) (S1) (S2) Purkiani et al. (in prep.)

22. Results of fully baroclinic 3D model (100 m resolution) Flood Ebb Purkiani et al. (in prep.)

23. 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)

24. Surface salinity at high and low water Burchard et al. (JPO 2008)

25. Withdensitydifferences Total waterand SPM volume V / km3 Burchard et al. (JPO 2008)

26. Withoutdensitydifferences Total waterand SPM volume V / km3 Burchard et al. (JPO 2008)

27. Sealevelrise & tidal flat growth (DanishWaddenSea) Data andgraphicsfrom Morten Pejrup, Copenhagen University