NUMERICAL SIMULATION OF DENSE WATER FORMATION PROCESSES IN THE NORTHERN ADRIATIC SEA STEFANO QUERIN1, CÉLIA LAURENT2, ALESSANDRO CRISE1, COSIMO SOLIDORO2 1 – ISTITUTO NAZIONALE DI OCEANOGRAFIA E DI GEOFISICA SPERIMENTALE (OGS) 2 – UNIVERSITÉ DE VERSAILLES SAINT-QUENTIN-EN-YVELINES ([email protected] / +39 040 2140376) OVERVIEW • simulation of dense water formation processes (VECTOR project) • preliminar numerical study of the hydrodynamic features of the Northern Adriatic Sea during winter • case study: winter 2006/2007 THE NUMERICAL MODEL MITgcm Ocean General Circulation Model [Marshall et al., 1997] MITgcm main features: • designed to study both atmospheric and oceanic phenomena • includes non-hydrostatic capability • adopts the KPP vertical turbulence parametrization • adopts a finite volume technique • developed to perform efficiently on a wide variety of computational platforms including MPI parallelizing directives MODEL EQUATIONS Du 1 ∂p − fv + = Eu Dt ρc ∂x Dv 1 ∂p + fu + = Ev Dt ρ c ∂y ε nh momentum equations Dw ρ 1 ∂p +g + = ε nhEw Dt ρc ρc ∂z ∂u ∂v ∂w + + =0 ∂x ∂y ∂z continuity equation ρ = ρ(θ , S) equation of state Dθ = Qθ Dt heat equation DS = QS Dt salt equation PRESSURE INTEGRATION p = ps + ph + pnh ps(x,y) pressure due to surface elevation (2-D elliptic equation) ph(x,y, z) hydrostatic pressure (2-D elliptic equation) pnh(x,y, z) non-hydrostatic pressure (3-D elliptic equation) GRAVITY PLUME ON A CONTINENTAL SLOPE Temperature after 23 hours of cooling. The cold dense water is mixed with ambient water as it accelerates down the slope and hence is warmer than the unmixed plume. • ∆ X = 12 ÷ 40 m • ∆ Z = 3.33 m • heat flux = 200 W/m2 TRACER ADVECTION MODEL CONFIGURATION • f-plane, 0.0225° spatial resolution • 43° rotation • 128 x 116 x 38 cells • 20 (2 m) + 18 (4 m) levels • bathymetry: 9 experimental data set 9 small manual adjustments • I.C.: 9 horizontally uniform 9 climatology • B.C.: 9 9 9 9 9 lateral no-slip quadratic bottom friction surface atmospheric forcing passive open boundary conditions Po river freshwater input COUPLING WITH ETA006 (CREST s.r.l.) Read-in uwind, vwind, atemp, aqh, swdown, lwdown, precip, and runoff. Compute ustress, vstress, hflux, swflux, and sflux. EFFECT OF BORA WIND 1/6 - weak Scirocco before the Bora episode EFFECT OF BORA WIND 2/6 – no wind before the Bora episode EFFECT OF BORA WIND 3/6 – strong Bora wind forcing EFFECT OF BORA WIND 4/6 – decreasing wind forcing EFFECT OF BORA WIND 5/6 – no wind after the Bora episode EFFECT OF BORA WIND 6/6 – no wind after the Bora episode EFFECT OF BORA WIND Vertical sections of density anomaly DONE... • successful implementation of a 3-D hydrodynamic model for the Northern Adriatic Sea • application to real a case study (winter 2006/2007) UNDER CONSTRUCTION... • application to several case studies • which are the phenomena that trigger the dense water flux? • computation of dense water mass production/fluxes ACKNOWLEDGEMENTS • VECTOR project • Alessandro Allodi (Regione Emilia Romagna, ARPA – SIM, Area Idrologia, PARMA) • CREST s.r.l. • Andrea Cimatoribus • Vanessa Cardin (OGS) THANKS!

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