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    • SEA LION - SEa ice in the Antarctic LInked with OceaN-atmosphere forcing

    Sea Lion is a joined EU-funded project of

  • Objektives and goals
  • The work packages
  • Project members
  • Papers and Presentations
  • References

    • Objectives and goals

    Presently, sea ice represents the weakest and least sophisticated part of coupled climate models. The aim of this project is to assess and improve the performance of coupled global atmosphere-sea ice-ocean models in reproducing sea ice in the high southern latitudes. This will be achieved by

    State of the Art

    On the geophysical scale sea ice is a thin, broken layer on the polar oceans which is modified in thickness and concentration by dynamic-thermodynamic processes. Sea ice represents the boundary between the two much larger geophysical fluids, the atmosphere and the ocean, and therefore influences their interaction considerably. The details and consequences of the role of sea ice in mediating between atmosphere and ocean are partly still unknown.

    Due to its high albedo and insulating behaviour sea ice modifies the heat, salt and momentum exchange between atmosphere and ocean. Since the sea ice is generally melted far away from the creation area, the ice drift also strongly modifies the buoyancy flux at the ocean surface. Because of its low salinity and negative latent heat the sea ice motion represents a very effective lateral heat and salt flux.

    A variety of large-scale sea ice models have been applied to the Arctic and Antarctic sea ice cover, ranging from very simple thermodynamic to highly sophisticated dynamic-thermodynamic models. These experiments suggest that the effects of sea ice dynamics cannot be omitted for realistic simulations of the sea ice cover, i. e. thickness, concentration and motion. In order to improve the results of sea ice models and to reduce computing time, modifications and fine-tuning of process parameterizations within the surface energy balance, the heat conduction and the dynamic codes seem to be necessary.

    CO2 warming experiments with global AOGCMs have shown an enhanced response in polar regions. This is in line with expectations. However, the details remain unclear because of an inadequate sea ice model. Coupled general circulation models (GCM) have in the past utilized thermodynamic sea ice models and - if at all - a simplified advection scheme. Presently dynamic-thermodynamic models (the cavitating fluid model (Flato and Hibler 1992) or versions of the original Hibler viscous-plastic model) are being implemented or have already been used at a few modelling centres. The use of the more sophisticated sea ice model component will allow a better evaluation of the role of the sea ice in the climate system, especially since these advanced sea ice models are less sensitive to internal perturbations and to changes of the boundary conditions in atmosphere and ocean.

    In order to understand and predict the interaction of atmosphere, sea ice and ocean in more detail an optimization of currently available sea ice models is necessary. Presently modelling activities, for example within the Sea Ice Modelling Intercomparison Project (SIMIP), are being coordinated by the Sea Ice-Ocean Modelling Panel (SIOM) of the Arctic Climate System Study (ACSYS) within the World Climate Research Programme (WCRP) to improve the dynamic part of sea ice models using observations of sea ice drift and the sea ice edge variability in the Arctic.

    A similar attempt to improve the thermodynamic part of sea ice models is still required. Within such a modelling exercise the following topics should be investigated:

    Due to the lack of sea ice motion data the optimization procedure has not yet been applied to Antarctic sea ice. An improved parameterization of the thermodynamic and dynamic processes for the Southern Ocean sea ice is only feasible with improved sea ice concentration and velocity data. Therefore, the objectives of this proposal are:

    The work packages

    The work within this project is subdivided into six tasks, each containing several work packages. Tasks 1 to 3 belong to the Remote Sensing Part, tasks 4 to 6 belong to the Modelling Part.

    Remote Sensing Part:

    Modelling Part:

    Projekt members

  • Institute of Marine Research (IfM)
    • Peter Lemke plemke@awi-bremerhaven.de
    Markus Harder mharder@ifm.uni-kiel.de
    Thomas Martin tmartin@ifm.uni-kiel.de
    Holger Pohlmann hpohlmann@ifm.uni-kiel.de
    Oliver Stenzel ostenzel@ifm.uni-kiel.de
  • British Antarctic Survey (BAS)
    • William Connolley wmc@bas.ac.uk
    Steven Harangozo sah@bas.ac.uk>
    John King j.c.king@bas.ac.uk
    Sandra Schuster ssc@bas.ac.uk
    John Turner j.turner@bas.ac.uk
  • Technical University of Denmark, Danish Center of Remote Sensing (DTU, DCRS)
    • Leif Toudal Pedersen ltp@emi.dtu.dk
    Roberto Saldo rs@emi.dtu.dk
  • University of Bremen, Institute of Remote Sensing (IUP)
    • Georg Heygster heygster@physik.uni-bremen.de
    Klaus-Peter Johnsen johnsen@gkss.de
    Stefan Kern kern@ifm.uni-hamburg.de
  • Deutsches Klimarechenzentrum (DKRZ)
    • Ulrich Cubasch cubasch@dkrz.de
    Josef Oberhuber oberhuber@dkrz.de
  • Hadley Centre for Climate Prediction and Research (HAD)
    • Douglas Cresswell dcresswell@meto.gov.uk

    Links to other sites and organisations

  • European Union (EU)
  • World Meteorological Organisation (World Climate Research Programme WCRP)(WMO)
  • Antarctic CRC (Cooperative Research Centre for the Antarctic and Southern Ocean environment)(CRC)
  • Antarctic Meteorological Research Center (AMRC)
  • Alfred Wegener Institute for Polar and Marine Research (AWI)

    • Papers and Presentations

    1998:

  • Lemke, P., Heygster, G., Toudal, L. Turner, J., 1998:
    • SEa ice in the Antarctic LInked with OceaN-atmosphere forcing, Proceedings of the European Climate Science Conference, Vienna, 19.-23. Oct. 1998.

    1999:

  • Kern, S., Heygster, G., and Miao, J., 1999:
    • Towards retrieval of Antarctic sea ice using the SSM/I 85.5 GHz polarization difference, Proc.IEEE International Geoscience and Remote Sensing Symposium, Hamburg, Germany, June 28 to July 2, 1999, 1031-1033.
  • Miao, J., Johnsen, K.-P., and Heygster, G., 1999:
    • Signature of clouds over sea ice detected by the Special Sensor Microwave/Imager (SSM/I), Proc. IEEE International Geoscience and Remote Sensing Symposium, Hamburg, Germany, June 28 to July 2, 1999, 2075-2077.
  • Pohlmann, H., Harder, M., Martin, T., and Lemke, P., 1999:
    • Comparisons of two ice simulations forced with ECMWF and NCEP/NCAR reanalyses data, Conference Proceedings of the Second International Conference on Reanalyses, Reading, UK, 1999, in press.

    2000:

  • Harangozo, S. A., 2000:
    • A search for ENSO teleconnections in the West Antarctic Peninsula Climate in Austral Winter, Int. J. Climatol., 20,663-679.
  • Kern, S., 2000:
    • Sea ice concentration derived using SSM/I 85.5 GHz imagery, Proc. Workshop on Mapping and archiving of sea ice data - The expanding role of RADAR, Ottawa, Canada, May 2-4, 2000, 179-184.
  • Kern, S. and Heygster, G., 2000:
    • Sea ice concentration retrieval in the Antarctic based on the SSM/I 85 GHz polarization, Symposium of the International Glaciology Society, IGS2000, Fairbanks, Alaska, June 19-23, 2000.
  • Lemke, P., Heygster, G., Toudal, L., and Turner, J., 2000:
    • The SEA LION Project: Sea ice in the Antarctic linked with ocean-atmosphere forcing, Symposium of the European Geophysical Society, EGS2000, Nice, France, April, 2000.
  • Martin, T., Pohlmann, H., Toudal, L, and Saldo, R., 2000:
    • Comparison of Southern Ocean sea ice drift simulations and satellite derived ice drift data, Symposium of the European Geophysical Society, EGS2000, Nice, France, April, 2000.
  • Schuster, S., Connolley, W., and Turner, J., 2000:
    • Assessment of a coupled atmosphere-ocean GCM with a dynamic-thermodynamic sea ice model, Symposium of the International Glaciology Society, IGS2000, Fairbanks, Alaska, June, 2000.
  • Stenzel, O., Pohlmann, H., Harder, M., Lemke, P., and Martin, T., 2000:
    • Results from the SEA LION Project: Interannual variability of simulated sea ice properties in the Southern Ocean, Symposium of the European Geophysical Society, EGS2000, Nice, France, April, 2000.
  • Toudal, L. and Saldo, R., 2000:
    • A dataset of satellite derived ice motion for the Southern Ocean, Symposium of the European Geophysical Society, EGS2000, Nice, France, April, 2000.
  • Turner, J., Connolley, W., Cresswell, D., and Harangozo, S., 2000:
    • The simulation of Antarctic sea ice in the Hadley Centre Climate Model (HadCM3), Symposium of the International Glaciology Society, IGS2000, Fairbanks, Alaska, June 19-23, 2000.

    2001:

  • Kern, S. and Heygster, G., 2001:
    • Sea ice concentration retrieval in the Antarctic based on the SSM/I 85 GHz polarization, Annals of Glaciology, 2001, in press.

    References

  • Flato, G.M, HiblerIII, W.D., 1992:
    • Modelling pack ice as a cavitating fluid - J. Phys. Oceanogr., 22,626-651
  • National Snow and Ice Data Center (NSIDC), 1996:
    • DMSP SSM/I Brightness temperatures and sea ice concentration grids for Polar Regions, User's guide, University of Colorado, Boulder, Colorado, CO 80309-0449, USA, pp.110.

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  • This page is under construction !
    Please send comments to Stefan Kern kern@ifm.uni-hamburg.de