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, Italy2-Ecole Nationale Supérieure de Techniques Avancées (ENSTA), Paris, France3-CNR ISMAR Sezione di La Spezia, Italy

Workshop W10 Vector Rimini 10-11 Settembre 2007

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

dtz

PONw

z

DONtw

z

NOk

ztwsmsdt

t

Nst

t

)())((0 3

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 baseof the euphotic zone

Steady state

Biological carbon cycle is non linearly coupled with nutrient cycles

unfortunately

Diatoms

Flagellates

Picophytoplankton

L PhotoadaptationL

P(1)

Large Phyto.LP(4)

LP(2)

LP(3)

Oxygen

Carbon dioxide

O Dissolved Gases

O(2)

O(3)

Phosphate

Nitrate

Ammonium

Silicate

N Inorganic NutrientsN(1)

N(3)

N(5)

Red. EquivalentsN(6)

N(4)

ZMicrozooplankton

(s.s.)

Heterotrophic

nanoflagellates

MicrozooplanktonZ

i(5)

Zi(6)

Carnivorous

Omnivorous

Z Mesozooplankton

Zi(3)

Zi(4)

B

Bacteria (aerobic

and anaerobic)

Bacterioplankton

Bi

Dissolved

Particulate (detritus)

R Organic Matter

Ri(1)

Ri(6)

Diatoms

Flagellates

Picophytoplankton

P PhytoplanktonP

i(1)

Large Phyto.Pi(4)

Pi(2)

Pi(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 MODELThe BIOGEOCHEMICAL FLUX MODEL

interpolation interpolation1/8° 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/loadOffl

ine

Dyn

am

ics

Tr a

nsp

ort

Bio

logy

Biogeochemical Flux Model

Numerical tool: Mediterranan Sea eco-hydrodinamical coupled modelStructure

1/16 dynamical model

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) CERFACSCode: OPA (Madec et al. 1997)

FORCING AND I.C. USED IN THE DYNAMICAL MODEL SIMULATION

MED16--ECMWF1/16° degree resolution; 43 vertical levelsHigher 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 yearsMonthly runoff UNESCO

Medar Medatlas DATASET vertical profiles

Initialization of nutrients fields

phosphates, nitrates, silicates, oxygen

Diffusive attenuation coefficient from satellite SeaWiFS data http://seadas.gsfc.nasa.gov/PRODUCTS/SW_k490.html

With coastal area Without coastal area

1997-2004 Climatological Seasons

Data provided by Gianluca Volpe and Lia Santoleri

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