Ocean modelling


We work with process oriented modelling and develop time-dependent coupled-basin models in close relation to validation and analyses of forcing data (e.g. Omstedt and Hansson, 2006 a,b, Hansson and Omstedt, 2007). An introduction to process-oriented lake and ocean modelling is given in Omstedt (2008). For the Baltic Sea we use the PROBE-Baltic model. The model uses the PROBE program for solving a number of equations. The building of PROBE-Baltic started in the early 1980’s. The first problem considered was cooling of the ocean surface layer around the temperature of maximum density and forecasting sea surface cooling. A four coupled basin model for the Baltic Sea entrance area were then formulated to analyses the effects of advection on the surface heat balance. In 1990, the first version of PROBE-Baltic was published, where the Baltic Sea was divided into 13 sub-basins and applied as a forecasting model. At this stage sea ice was not included but a new ice model for coastal seas was developed. Sea ice processes were then studied and in 1996 a coupled ice-ocean version of PROBE-Baltic was published and the climate sensitivity of the Baltic Sea was examined. The deep-water circulation and salinity as well as temperature variations were later examined. The PROBE-Baltic model has also been applied in a number of other works related to climate, water and heat balances studies. A full description of the mathematical modelling, covering forcing as well as validation data, appears in Omstedt and Axell (2003).

 

(Click image to enlarge)

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Figure 1. A sketch of some important processes to be considered in Baltic Sea modelling. From Winsor et al. (2001, 2003).

 

References:

  • Omstedt, A., and D., Hansson, (2006 a). The Baltic Sea ocean climate system memory and response to changes in the water and heat balance components. Continental Shelf Research, 26, 236-251. DOI: 10.1016/j.csr.2005.11.003
  • Omstedt, A., and D., Hansson, (2006 b). Erratum to: “The Baltic Sea ocean climate system memory and response to changes in the water and heat balance components”. Continental Shelf Research, 26, 1685-1687. DOI: 10.1016/j.csr.2006.05.011
  • Hansson, D., and A., Omstedt, (2007). Modelling the Baltic Sea ocean climate on centennial time scales; Temperature and Sea Ice. Climate Dynamics, accepted. DOI: 10.1007/s00382-007-0321-2
  • Omstedt, A. (2008). Process-oriented numerical modelling of lakes, coastal seas, and oceans. Part I: Physical aspects. Available from the author.
  • Omstedt, A. and L., Axell (2003). Modeling the variations of salinity and temperature in the large Gulfs of the Baltic Sea. Continental Shelf Research, 23, 265-294.
  • Winsor, P., J. Rodhe, and A. Omstedt (2003). Erratum: Baltic Sea ocean climate: an analysis of 100 yr of hydrographic data with focus on the freshwater budget, Climate Research, 25, 183.
  • Winsor, P., J. Rodhe, and A. Omstedt (2001). Baltic Sea ocean climate: an analysis of 100 yr of hydrographic data with focus on the freshwater budget, Clim. Res., 18, 5-15.


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