1. Decadal simulations of the Mediterranean Sea ecosystem with a 3D Biogeochemical model CRISE ALESSANDRO 1, LAZZARI PAOLO 1, SALON STEFANO 1, TREVISANI SEBASTIANO 1, BERANGER KARINE 2, SCHRÖDER KATRIN 3 1-Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Trieste, Italy 2-Ecole Nationale Supérieure de Techniques Avancées (ENSTA), Paris, France 3-CNR ISMAR Sezione di La Spezia, Italy Workshop W10 Vector Rimini 10-11 Settembre 2007

2. VECTOR Activity 8.6 6.3) Coupling of a biogeochemical-hydrodynamical model of the system describing the cycles of azote, phosphorus, and carbon with the general circulation of the Mediterranean Sea; 6.4) Analyses of datasets coming from in situ and remote measurements and preparation of initial and boundary conditions; 6.5) Sensitivity analyses of the impacts in changing forcing on the trophic web; 6.7) Synthetic analyses of the result of numerical simulations and estimation of carbon fluxes in pelagic systems; Overall objective: estimate the present export of carbon from the productive layer follow the fate of the export production

3. General framework: biological pump estimate The vertical flux in nitrogen is supposed to be balanced on an annual scale integrated over the basin (Eppley and Peterson, 1979 revisited) sms= land input+river load+atmospheric input-Gibraltar budget Nitrogen input at the base of the euphotic zone Nitrogen export at the base of the euphotic zone Steady state Biological carbon cycle is non linearly coupled with nutrient cycles unfortunately

4. Diatoms Flagellates Picophytoplankton L Photoadaptation L P (1) Large Phyto. L P (4) L P (2) L P (3) Oxygen Carbon dioxide ODissolved Gases O (2) O (3) Phosphate Nitrate Ammonium Silicate NInorganic Nutrients N (1) N (3) N (5) Red. Equivalents N (6) N (4) Z Microzooplankton (s.s.) Heterotrophic nanoflagellates Microzooplankton Z i (5) Z i (6) Carnivorous Omnivorous ZMesozooplankton Z i (3) Z i (4) B Bacteria (aerobic and anaerobic) Bacterioplankton BiBi Dissolved Particulate (detritus) R Organic Matter R i (1) R i (6) Diatoms Flagellates Picophytoplankton P Phytoplankton P i (1) Large Phyto. Pi(4)Pi(4) P i (2) P i (3) Vectors ( Functional Group or Ordinary State Variables) Organic matter flow (C,N,P,Si) Inorganic nutrient flow (N,P,Si) Gas exchange Benthic-Pelagic flow Scalars ( Ordinary State Variables) Z The BIOGEOCHEMICAL FLUX MODEL

5. interpolation interpolation 1/8° OGS/OPA Tracer Model V. Eddy Diffusivity Velocity field Wind speed Biogeochemical source terms Lateral and surface BCs ORCA2/PISCES (global) Physical source terms Mesh/masks (curvilinear coordinates) Temperature Salinity Radiative fluxes River runoff/load Offline Dynamics Transport Biology Biogeochemical Flux Model Numerical tool: Mediterranan Sea eco-hydrodinamical coupled model Structure 1/16 dynamical model

6. Ongoing work: mesh of the physical model PAM/PSY2v1 MED16 model http://www.lodyc.jussieu.fr/equipes/mediterranee/project/med16 PAM (Drillet et al. 2001) CERFACS Code: OPA (Madec et al. 1997)

7. FORCING AND I.C. USED IN THE DYNAMICAL MODEL SIMULATION MED16--ECMWF 1/16° degree resolution; 43 vertical levels Higher in Gibraltar Strait through curvilinear grid Initial conditions for dynamical model: T,S seasonal, climatology MODB-4 Atmospheric Forcing : ECMWF Analyses (0.5 o ) Daily fluxes 1/03/1998-2006 = 9 years Monthly runoff UNESCO

8. Medar Medatlas DATASET vertical profiles Initialization of nutrients fields phosphates, nitrates, silicates, oxygen

9. Diffusive attenuation coefficient from satellite SeaWiFS data http://seadas.gsfc.nasa.gov/PRODUCTS/SW_k490.html With coastal areaWithout coastal area 1997-2004 Climatological Seasons Data provided by Gianluca Volpe and Lia Santoleri

10. Model qualification The qualification of the model is on-going. The procedures described in the MERSEA technical report MERSEA-WP05-MERCA-STR-0007-1A0 List of internal metrics, specifications for implementation are applied: here are presented Class 1 consistency tests Consistency test: comparison between patterns of chlorophyll content in the First optical depth obtained by satellite data and model outputs

11. Comparison of OPA Model Surface Chla and Satellite data

16. Hovmoller diagram for chl-a From DYFAMED station measurements (Marty et al, 2002)

17. Hovmoller diagram for chl-a (shaded) and phosphate (contour) in the area of DYFAMED station 7° 52’ E, 43° 52’ N

18. NO CONCLUSIONS