1 / 44

Hans Burchard … … and many others from inside and outside IOW Leibniz Institute for

The overturning circulation of the Baltic Sea and its ecological consequences. Hans Burchard … … and many others from inside and outside IOW Leibniz Institute for Baltic Sea Research Warnemünde hans.burchard@io-warnemuende.de. The Baltic Sea. Baltic Sea under stress.

manjit
Download Presentation

Hans Burchard … … and many others from inside and outside IOW Leibniz Institute for

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The overturning circulation of the Baltic Sea and its ecological consequences Hans Burchard … … and many others from inside and outside IOW Leibniz Institute for Baltic Sea Research Warnemünde hans.burchard@io-warnemuende.de

  2. The Baltic Sea

  3. Baltic Seaunder stress Climate change Eutrophication IPCC BACC Constructions Fishery

  4. www.getm.eu

  5. The philosophybehind GETM GETM is a coastalandshelfsea (andlake?) hydrodynamic model. GETM is a Public Domain Community Model. GETM isreleasedunderthe Gnu Public Licence. GETM is Open Source. GETM has a modular structure (open forextentions). GETM has an international developerandusercommunity. GETM started in 1997 andhasbeensteadilydevelopedsincethen.

  6. Nested modelling hierarchy Gräwe et al. (in prep.)

  7. Domain decomposition Gräwe et al. (in prep.)

  8. Example for simulated summer sea surface temperature Gräwe et al. (in prep.)

  9. Example for simulated bottom salinity Gräwe et al. (in prep.)

  10. Baltic Sea salinity October 2002 (before inflow) Baltic Sea major inflow event T and S atDarss Sill in 2003 June 2003 (after inflow)

  11. Baltic Sea oxygen concentration hydrogen sulfur October 2002 (before inflow) June 2003 (after inflow)

  12. Oxygen observations in thecentral Baltic Sea Reissmann et al. (2009)

  13. Baltic Sea suboxic and anoxic areas before major inflow

  14. Baltic Sea suboxic and anoxic areas after major inflow

  15. Historyof Major Baltic Inflows (MBIs) Matthäus (2006)

  16. Data from Markus Meier, SMHI (in Burchard et al., 2008)

  17. Proxies: surface water conditions, central Baltic Tex-86 derived SST 232 m water depth MODIS Rapid Response System Kabel et al. 2012 (Nature Climate Change)

  18. Proxies: surface water conditions, central Baltic Tex-86 derived SST 175 m water depth MODIS Rapid Response System Kabel et al. 2012

  19. Baltic Seaoverturningcirculation

  20. Howisthe Baltic Seaoverturningcirculationclosed? Exchange flow Inflows Boundaryand internalmixing Reissmann et al., 2009

  21. Knudsen formula Volume conservation: s=0 Salt conservation: 0

  22. Computersimulation Western Baltic Sea

  23. Computersimulation Western Baltic Sea

  24. Model validation: Data Darsser Schwelle Burchard et al. (2009)

  25. Beforeinflow Duringinflow + Drogden Sill + Kriegers Flak N + Darss Sill Rennau & Burchard, 2009

  26. Detailedinflow study in 2005 Umlauf et al. (2007) FS Professor Albrecht Penck Kriegers Flak Schweden 16.11.2005

  27. Observed Transverse Structure (Nov 2005) Down-channelvelocity Dissipation rate Cross-channelvelocity BBL mixing Interfacialmixing Quiescentcore Slopemixing • wegde-shapedinterface • interfacejet • lateral buoyancygradient in interior • three-layertransversecirculation Umlauf et al., GRL, (2007) Umlauf et al. (2007), Reissmann et al. (2009), Umlauf & Arneborg (2009a,b)

  28. Which is the most simple model that can reproduce this? • 2-D shallow-water equations (GETM) • homogenous in down-channel direction • ‘infinitely’ deep • 2nd-moment turbulence closure model (GOTM) • adaptive coordinates Umlauf et al. (2010)

  29. Surfacesalinitylagsmorethan 10 yearsbehindbottomsalinity Feistel, 2005

  30. Reissmann et al. 2009 Mixing processes in the Baltic Sea Courtesy Peter Holtermann

  31. Reissmann et al. 2009 Investigation ofdeepwatermixingduring a stagnationperiod Courtesy Peter Holtermann

  32. Boundary Mixing Internal Mixing Reissmann et al. 2009 Investigation ofdeepwatermixingduring a stagnationperiod Courtesy Peter Holtermann

  33. The Baltic Sea Tracer Release Experiment Tracer Spreading Courtesy Peter Holtermann

  34. Interior Diffusivity NormalisedtracerprofileOct. 2007 44 DAI m2/s m2/s Holtermann et al. (2012)

  35. Basin wide eddy diffusivity Leg 3 Feb. 2008 Basin-widemixingisone order ofmagnitude larger thanlocaldiffusivity ! Leg 4 July 2008 OnediffusivityfitsT, S, tracer ! Holtermann et al. (2012)

  36. Tracer experiment

  37. The Baltic Seaas a complexecosystem Climate Input Sensitive Nonlinear Response Ecosystem output Air N2 Cyanobacteria     Surfacewater  random ventilation mixing  settling    Random ventilation Chemical switch P Deepwater O2 H2S O2 O2-Depletion P Sediment

  38. Near-bottomoxygen & phosphateobservations in thecentral Baltic Sea Reissmann et al. (2009)

  39. Phosphate concentrations in winter surface layer in the Eastern Gotland Basin Reissmann et al. (2009)

More Related