Workshop W10 Vector Rimini 10-11 Settembre 2007
Decadal simulations of the Mediterranean Sea ecosystem with
a 3D Biogeochemical model
CRISE ALESSANDRO1, LAZZARI PAOLO1, SALON STEFANO1, TREVISANI SEBASTIANO1,
BERANGER KARINE2, SCHRÖDER KATRIN3
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
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
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)
N
t t dt  0 
Steady state

t
 NO3
DON
PON
sms ( w(t )  k )
 w(t )
 ws
dt
z
z
z
z
Nitrogen input at the base
of the euphotic zone
Nitrogen export at the base
of the euphotic zone
sms= land input+river load+atmospheric input-Gibraltar budget
unfortunately
Biological carbon cycle is non linearly coupled with nutrient cycles
The BIOGEOCHEMICAL FLUX MODEL
O Dissolved Gases
R
Ri(1)
Ri(6)
Organic Matter
Z Mesozooplankton
Dissolved
Zi(3) Carnivorous
Particulate (detritus)
Zi(4) Omnivorous
Z Microzooplankton
Zi(5) Microzooplankton
(s.s.)
Zi(6)
Heterotrophic
nanoflagellates
L Photoadaptation
LP(1)
Diatoms
P Phytoplankton
(1) Diatoms
Flagellates
LP(2) P
i
(2)
LP(3) PPicophytoplankton
Flagellates
i
B Bacterioplankton
Bi Bacteria (aerobic
O(2) Oxygen
O(3) Carbon dioxide
N Inorganic Nutrients
N(1) Phosphate
N(3) Nitrate
N(4) Ammonium
N(5) Silicate
N(6) Red. Equivalents
(3) Phyto.
LP(4) PLarge
Picophytoplankton
i
Pi(4) Large Phyto.
and anaerobic)
Vectors
(Functional Group or
Scalars
Organic matterInorganic nutrientGas
Benthic-Pelagic
(Ordinary Stateflow (C,N,P,Si) flow (N,P,Si)
exchangeflow
Ordinary State Variables)Variables)
Structure
Numerical tool: Mediterranan Sea eco-hydrodinamical coupled model
1/16 dynamical model
Temperature
Mesh/masks
•V. Eddy Diffusivity
Salinity
(curvilinear
coordinates)
•Velocity field
Radiative fluxes
•Wind speed
River runoff/load
interpolation
interpolation
1/8° OGS/OPA
Tracer Model
Physical source
terms
Lateral and
surface BCs
Biogeochemical Flux
Model
ORCA2/PISCES
(global)
Biogeochemical
source terms
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)
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 (0.5o)
Daily fluxes 1/03/1998-2006 = 9 years
Monthly runoff UNESCO
Initialization of nutrients fields
Medar Medatlas DATASET vertical profiles
phosphates, nitrates, silicates, oxygen
Diffusive attenuation coefficient from satellite SeaWiFS data
http://seadas.gsfc.nasa.gov/PRODUCTS/SW_k490.html
Data provided by Gianluca Volpe and Lia Santoleri
1997-2004 Climatological Seasons
With coastal area
Without coastal area
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
Comparison of OPA Model Surface Chla and Satellite data
Comparison of OPA Model Surface Chla and Satellite data
Comparison of OPA Model Surface Chla and Satellite data
Comparison of OPA Model Surface Chla and Satellite data
Comparison of OPA Model Surface Chla and Satellite data
Hovmoller diagram for chl-a
From DYFAMED station measurements (Marty et al, 2002)
Hovmoller diagram for chl-a (shaded) and phosphate (contour)
in the area of DYFAMED station 7° 52’ E, 43° 52’ N
NO CONCLUSIONS