1. Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas Physical and Biogeochemical Coupled Modelling Presented by Christel PINAZO Mediterranean University Oceanographic Center of Marseille Physical & Biogeochemical Oceanographic Laboratory

2. Introduction Why use Coupled Models ? Historical considerations Different types of Coupled Models Box models Fine grid Models (1D, 2D and 3D) Different ways of Coupling Models « Off-line » Coupling « On-line » Coupling Examples LECTURE SCHEDULE

3. Introduction Why use Coupled Models ? Historical considerations Different types of Coupled Models Box models Fine grid Models (1D, 2D and 3D) Different ways of Coupling Models « Off-line » Coupling « On-line » Coupling Examples LECTURE SCHEDULE

4. INTRODUCTION WHY USE PHYSICAL AND BIOGEOCHEMICAL COUPLED MODELS TO STUDY ECOSYSTEM FUNCTIONING? Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTION > WHY?COUPLING TYPESCOUPLING WAYS EXAMPLES

5. INTRODUCTION A BIOGEOCHEMICAL MODEL TO DESCRIBE ECOSYSTEM FUNCTIONING Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTION > WHY?COUPLING TYPESCOUPLING WAYS EXAMPLES

6. Sediment River Inputs Schematic Marine Ecosystem IRRADIANCE Nutrients POM DOM Erosion Benthic Fluxes Phytoplankton Uptake Exudation Zooplankton Grazing Faeces Bacteria Mineralisation Uptake GEOCHEMICAL MODEL Atmospheric inputs T° BIOGEOCHEMICAL MODEL

7. INTRODUCTION A PHYSICAL MODEL TO DESCRIBE ECOSYSTEM FORCING CONDITIONS Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTION > WHY?COUPLING TYPESCOUPLING WAYS EXAMPLES

8. Sediment Schematic Marine Ecosystem IRRADIANCE Nutrients POM DOM Erosion Benthic Fluxes Phytoplankton Zooplankton Bacteria PHYSICAL MODEL River Inputs Atmospheric inputs Tide WIND Waves Currents T°

9. INTRODUCTION A PHYSICAL AND BIOGEOCHEMICAL COUPLED MODEL IS NEEDED TO DESCRIBE BOTH ECOSYSTEM FUNCTIONING AND FORCING CONDITIONS Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTION > WHY?COUPLING TYPESCOUPLING WAYS EXAMPLES

10. Introduction Why use Coupled Models ? Historical considerations Different types of Coupled Models Box models Fine grid Models (1D, 2D and 3D) Different ways of Coupling Models « Off-line » Coupling « On-line » Coupling Examples LECTURE SCHEDULE

11. INTRODUCTION Physical and Biogeochemical Coupled Modelling is a Recent Scientific Discipline Developed since the 1990’s Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTION > HISTORY COUPLING TYPES COUPLING WAYS EXAMPLES

12. BECAUSE Biogeochemical Modelling was Developed since the 1940’s with Riley’s (1946) and Steele’s (1962) Models INTRODUCTION Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTION > HISTORY COUPLING TYPES COUPLING WAYS EXAMPLES 1

13. PHYTOPLANKTON MODELS Riley’s Model (1946) Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTION > HISTORY COUPLING TYPES COUPLING WAYS EXAMPLES From Tett & Wilson (2000) Phytoplankton Carbon Concentration Phytoplankton Carbon Concentration Photosynthesis Respiration Grazing Photosynthesis depending on light limitation Steele’s Model (1962)

14. N-P-Z-D MODELS Fasham’s Model (1990) Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTION > HISTORY COUPLING TYPES COUPLING WAYS EXAMPLES Nutrient-Phytoplankton-Zooplankton-Detritus PhytoplanktonDONNitrate Ammonium BacteriaZooplanktonDetritus

15. INTRODUCTION & BECAUSE Hydrodynamical Modelling was Developed since the 1970’s with the development of computers and computing resources Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTION > HISTORY COUPLING TYPES COUPLING WAYS EXAMPLES 2

16. INTRODUCTION POM was created by Blumberg in late 1970’s Blumberg & Yamada (1974) Blumberg & Mellor (1980)

17. INTRODUCTION THUS First coupled Models appeared in the 1980’s Cloern & Cheng (1981) 1DH (Phytopk) Klein & Coste (1984) 1DV (Nutrients) Klein & Steele (1985) 1DV (N-P) Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTION > HISTORY COUPLING TYPES COUPLING WAYS EXAMPLES 3

18. INTRODUCTION First 3D coupled Models appeared in the 1990’s Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTION > HISTORY COUPLING TYPES COUPLING WAYS EXAMPLES Sarmiento et al. (1993) (Fasham’s model) Buckley and O’Kane (1993) (GHER model) Skogen et al. (1995) (NORWECOM model) Six and Maier-Reimer (1996) (HAMOCC model) Pinazo et al. (1996) (ECO3M model)

19. Introduction Why use Coupled Models ? Historical considerations Different types of Coupled Models Box models Fine grid Models (1D, 2D and 3D) Different ways of Coupling Models « Off-line » Coupling « On-line » Coupling Examples LECTURE SCHEDULE

20. Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTION COUPLING TYPES COUPLING WAYS EXAMPLES COUPLING OR FORCING? THAT IS THE QUESTION! Ecological Model Hydrodynamic Model FORCING FEED BACK NO FORCING

21. Introduction Why use Coupled Models ? Historical considerations Different types of Coupled Models Box models Fine grid Models (1D, 2D and 3D) Different ways of Coupling Models « Off-line » Coupling « On-line » Coupling Examples LECTURE SCHEDULE

22. COUPLING TYPES Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTIONCOUPLING TYPES>BOX COUPLING WAYS EXAMPLES THE STUDY SITE COULD BE SPATIALLY DESCRIBED BY BOXES

23. SEDIMENT z=-h BOX MODEL Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTIONCOUPLING TYPES>BOX COUPLING WAYS EXAMPLES VERTICALLY HOMOGENEOUS O x y z z=0  Velocity =

24. CONSERVATION LAWS Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTIONCOUPLING TYPES>BOX COUPLING WAYS EXAMPLES TO CALCULATE ADVECTION OF BIOGEOCHEMICAL SUBSTANCES : - FLUID MASS CONSERVATION = CONTINUITY EQUATION - SUBSTANCE MASS CONSERVATION

25. CONSERVATION LAWS Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTIONCOUPLING TYPES>BOX COUPLING WAYS EXAMPLES FLUID MASS CONSERVATION = CONTINUITY EQUATION In case of incompressible fluids Density is constant

26. SEDIMENT z=-h BOX MODEL Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTIONCOUPLING TYPES>BOX COUPLING WAYS EXAMPLES O x y z z=0  Along Ox axis

27. SEDIMENT z=-h BOX MODEL Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTIONCOUPLING TYPES>BOX COUPLING WAYS EXAMPLES O x y z z=0  Along Ox axis

28. CONSERVATION LAWS Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTIONCOUPLING TYPES>BOX COUPLING WAYS EXAMPLES FLUID MASS CONSERVATION = CONTINUITY EQUATION In case of incompressible fluids is constant Boundary conditions along Oz axis:

29. CONSERVATION LAWS Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTIONCOUPLING TYPES>BOX COUPLING WAYS EXAMPLES FLUID MASS CONSERVATION = CONTINUITY EQUATION In case of incompressible fluids is constant

30. CONSERVATION LAWS Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTIONCOUPLING TYPES>BOX COUPLING WAYS EXAMPLES SUBSTANCE MASS CONSERVATION = STATE EQUATION C is the concentration of the substance

31. SEDIMENT z=-h BOX MODEL Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTIONCOUPLING TYPES>BOX COUPLING WAYS EXAMPLES O x y z z=0  Along Ox axis zz yy

32. CONSERVATION LAWS Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTIONCOUPLING TYPES>BOX COUPLING WAYS EXAMPLES SUBSTANCE MASS CONSERVATION = STATE EQUATION C is the concentration of the substance withAnd at the surface at the bottom

33. Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas INTRODUCTIONCOUPLING TYPES>BOX COUPLING WAYS EXAMPLES If C is the concentration of a biologic substance, C is not conservative BOX MODEL Concentration Trend term= Sources – Sinks

34. COUPLING TYPES Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas ADVANTAGES: -SHORT COMPUTATIONAL TIME -VERY LONG SIMULATION OF YEARS OR DECADES DISADVANTAGES: -MAINLY ADVECTIVE TRANSPORT: Paul Tett TRIED TO ADD VERTICAL EDDY DIFFUSIVITY THROUGH 3 VERTICAL LAYERS -ROUGH SPATIAL DESCRIPTION -NUMERICAL HORIZONTAL DIFFUSIVITY INTRODUCTIONCOUPLING TYPES>BOX COUPLING WAYS EXAMPLES BOX MODEL