Modeling the baroclinic circulation in the area of the Sicily channel: The role of stratification and energy diagnostics

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Abstract

Aspects of the circulation of the Sicily channel region are studied with a high-resolution, primitive equation, sigma coordinate model. This work is an attempt to study the process governing the purely baroclinic dynamics and its sensitivity to seasonal stratification, thus no atmospheric forcing is used. Two numerical experiments are analyzed using, as initial conditions, diagnostic velocity fields derived from the winter and summer climatological hydrologies. The quasi-steady state is characterized by circulation patterns, in the depth range of the Modified Atlantic Water (MAW) and the Levantine Intermediate Water (LIW), strongly controlled by mesoscale eddies and topography. Seasonal difference is found in the surface current which exhibits the major variability on the African side, downstream of Adventure Bank and the Ionian Slope where the absolute maximum occurs. The intermediate circulation instead does not show relevant seasonal differences. LIW enters through the two passages south of Malta Plateau and preferentially flows along the Sicilian shelf edge exiting over the northern sill. Its pathway is strongly controlled by subsurface cyclonic and anticyclonic cells. The results are in good agreement with observations. An energy diagnostics is applied to model results and sheds important light on dynamical characteristics of the mesoscale eddy field and indicates seasonal differences in the energetic exchange with the mean flow. The analysis of the mean (MKE) and eddy (EKE) kinetic energy, the transfer terms between energy compartments and the eddy momentum flux divergence indicates how eddies are strongly energetic in summer and exchange energy more efficiently with the mean flow. In the quasi-steady state MAW volume transport and MKE and EKE fluctuations are strongly correlated. This result suggests that mesoscale motions can control up to 40% of volume transport variability.
Original languageEnglish
Pages (from-to)23 - 1
JournalJournal of Geophysical Research
Volume108
Issue number7
Publication statusPublished - 15 Jul 2003
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

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