A Modelling Study For The Baroclinic Circulation In The Sicily Channel: Mesoscale Dynamics and Eddy-mean Flow Interactions
Abstract
The mesoscale dynamics and the ddy-mean flow interactions in the Sicily Channel area are studied by an high resolution, primitive equations, sigma coordinate model. Since one of the purpose of this study is to attempt to quantify the processes govern- ing the purely baroclinic dynamics, no atmospheric forcings are used in this frame- work. Two numerical experiments are basically analysed using, as initial conditions, the geostrophyc velocity fields derived diagnostically from climatological hydrolo- gies representing winter and summer state. Running the model prognostically a quasi- steady state is found where the circulation patterns, concerning the principal water masses (Modified Atlantic Water -MAW- and Levantine Intermediate Water -LIW- ) are in strong agreement with observations. The energetic diagnosis applied to the model results have shed important lights on the role of the two different extreme sea- sonal stratifications controlling the circulation in the surface layers. Both baroclinic and barotropic instabilities takes places in the generation of meanders and eddies and the mean kinetic energy (MKE) and eddy kinetic energy (EKE) are higher in summer than in winter. The quasi-steady state is characterized by strongly correlated fluctua- tions of MKE, EKE and volume transport. This correleation give an estimate of the effect of the mesoscale variability on the volume transport of the MAW. Eddy mo- mentum flux calculated by the model results is positive in both runs suggesting that locally eddies accelerate the momentum of the mean current.
- Publication:
-
EGS General Assembly Conference Abstracts
- Pub Date:
- 2002
- Bibcode:
- 2002EGSGA..27.1225N