HR: 11:50h
AN: OS52A-07    [Abstracts]
TI: Comparison Between Numerical Simulations and Drifter Observations of the Surface Circulation in the Adriatic Sea
AU: * Korotenko, K A
EM: konstantin.korotenko@dartmouth.edu
AF: Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, NH 03755, United States
AU: Poulain, P M
EM: ppoulain@ogs.trieste.it
AF: Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Borgo Grotta Gigante, 42/c, Sgonico (Trieste), 34010, Italy
AU: Cushman-Roisin, B R
EM: Benoit.R.Roisin@Dartmouth.edu
AF: Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, NH 03755, United States
AB: Eulerian statistics computed from drifter data and estimated from numerical simulations of circulation of the Adriatic Sea are compared for different seasons and wind forcing. The periods of interest are August-October 2003, May, June and February 2003, where drifter data have high density. The numerical simulations were performed with a 1.2- min resolution DieCAST Ocean Circulation Model adapted for the Adriatic Sea. The simulations resolve the mesoscale variability because the grid size falls below the first baroclinic deformation radius (about 5-10 km) and the model has very low horizontal dissipation. The DieCAST model is initialized with seasonally averaged temperature and salinity data and forced with climatological winds and surface buoyancy fluxes (both heat flux and evaporation minus precipitation). River discharges are varied daily according to a perpetual year for every river, and the open-boundary conditions at Otranto Strait are obtained by nesting in two larger-scale models (Cushman-Roisin et al., JGR, 2007). In the period of interests the model was forced with the COAMPS wind stresses and heat fluxes. Mean Kinetic Energy (MKE) and Eddy Kinetic Energy (EKE) estimates were obtained using the methodology commonly used with drifter (Poulain, JMS, 2001). The surface drifter observations were obtained in 2002 and 2003 as part of the DOLCEVITA project (Ursella et al., JGR, 2006). More than 120 CODE drifters were released in the northern and middle Adriatic with the purpose of studying the surface circulation at mesoscale to seasonal scale in relation to wind forcing. Drifter velocities were low-pass filtered to eliminate tidal and inertial currents. Comparison of the MKE and EKE computed from the model and drifter data shows a good agreement for high- energy dynamics along the Italian coast and local effects of strong winds like Bora and Sirocco. Discrepancies between the drifter-based and model-inferred Eulerian statistics originates in the specification of the present version of the model, i.e., its vertical architecture does not allow to resolve adequately the thin surface layer. In this connection, drifter observations provide valuable data allow improving and tuning circulation models.
UR: http://www.ogs.trieste.it
DE: 4217 Coastal processes
DE: 4255 Numerical modeling (0545, 0560)
DE: 4260 Ocean data assimilation and reanalysis (3225)
DE: 4262 Ocean observing systems
DE: 4512 Currents
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting