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 PINAZOMediterranean University

Oceanographic Center of MarseillePhysical & Biogeochemical Oceanographic Laboratory

• IntroductionWhy 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

• IntroductionWhy 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

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 TYPES COUPLING WAYS EXAMPLES

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 TYPES COUPLING WAYS EXAMPLES

Sediment

River Inputs

Schematic Marine

Ecosystem

IRRADIANCE

NutrientsPOM DOM

ErosionBenthic Fluxes

Phytoplankton

UptakeExudationZooplankton

Grazing

Grazing

Grazing

Faeces

Bacteria

Mineralisation

Uptake

GEOCHEMICAL MODEL

Atmospheric inputs

T°

BIOGEOCHEMICAL MODEL

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 TYPES COUPLING WAYS EXAMPLES

Sediment

Schematic Marine

Ecosystem

IRRADIANCE

NutrientsPOM DOM

ErosionBenthic Fluxes

Phytoplankton

Zooplankton

Bacteria

PHYSICAL MODEL

River InputsAtmospheric inputs

TideWIND

WavesCurrents

T°

INTRODUCTION

A PHYSICAL AND BIOGEOCHEMICAL COUPLED MODEL

IS NEEDED TO DESCRIBE

BOTHECOSYSTEM FUNCTIONING AND FORCING CONDITIONS

Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas

INTRODUCTION > WHY? COUPLING TYPES COUPLING WAYS EXAMPLES

• IntroductionWhy 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

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

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

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 CarbonConcentration

Phytoplankton Carbon

Concentration

PhotosynthesisRespiration

Grazing

Photosynthesis depending on light limitation

Steele’s Model (1962)

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

PhytoplanktonDON Nitrate

Ammonium

Bacteria Zooplankton Detritus

INTRODUCTION

&BECAUSE

Hydrodynamical Modellingwas

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

INTRODUCTION

POM was created by

Blumberg in late 1970’s

Blumberg & Yamada (1974)

Blumberg & Mellor (1980)

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

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)

• IntroductionWhy 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

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!

EcologicalModel

HydrodynamicModel

FORCING

FEED BACK NO

FORCING

• IntroductionWhy 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

COUPLING TYPES

Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas

INTRODUCTION COUPLING TYPES >BOX COUPLING WAYS EXAMPLES

THE STUDY SITE COULD BE SPATIALLY DESCRIBED BY BOXES

SEDIMENT

z=-h

BOX MODEL

Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas

INTRODUCTION COUPLING TYPES >BOX COUPLING WAYS EXAMPLES

VERTICALLY HOMOGENEOUS

O x

y

z

z=0

w

v

u

v

Velocity =

CONSERVATION LAWS

Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas

INTRODUCTION COUPLING TYPES >BOX COUPLING WAYS EXAMPLES

TO CALCULATE ADVECTION OF BIOGEOCHEMICAL SUBSTANCES :

- FLUID MASS CONSERVATION = CONTINUITY EQUATION

- SUBSTANCE MASS CONSERVATION

CONSERVATION LAWS

0

z

w

y

v

x

u

Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas

INTRODUCTION COUPLING TYPES >BOX COUPLING WAYS EXAMPLES

FLUID MASS CONSERVATION = CONTINUITY EQUATION

In case of incompressible fluids

0 Density is constant

SEDIMENT

z=-h

BOX MODEL

Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas

INTRODUCTION COUPLING TYPES >BOX COUPLING WAYS EXAMPLES

O x

y

z

z=0

Along Ox axis

inu outuinout xxx

SEDIMENT

z=-h

BOX MODEL

Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas

INTRODUCTION COUPLING TYPES >BOX COUPLING WAYS EXAMPLES

O x

y

z

z=0

Along Ox axis

inu outu x

uu

x

u inout

inout xxx

CONSERVATION LAWS

0

z

w

y

v

x

u

Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas

INTRODUCTION COUPLING TYPES >BOX COUPLING WAYS EXAMPLES

FLUID MASS CONSERVATION = CONTINUITY EQUATION

In case of incompressible fluids

0 is constant

Boundary conditions along Oz axis:

0bottomw

twsurface

zt

z

w

0

( )z h D

CONSERVATION LAWS

0u v

D Dt x y

Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas

INTRODUCTION COUPLING TYPES >BOX COUPLING WAYS EXAMPLES

FLUID MASS CONSERVATION = CONTINUITY EQUATION

In case of incompressible fluids

0 is constant

CONSERVATION LAWS

?t

C

Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas

INTRODUCTION COUPLING TYPES >BOX COUPLING WAYS EXAMPLES

SUBSTANCE MASS CONSERVATION = STATE EQUATION

C is the concentration of the substance

SEDIMENT

z=-h

BOX MODEL

Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas

INTRODUCTION COUPLING TYPES >BOX COUPLING WAYS EXAMPLES

O x

y

z

z=0

Along Ox axis

. . .in in inM C u y z . . .out out outM C u y z

Vol

MM

x

C inout

z

y

inout xxx

CONSERVATION LAWS

. . . . . . . . . . . .0out out in in out out in in out out in inC u C u y z C v C v x z C w C w x yC

t Vol Vol Vol

Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas

INTRODUCTION COUPLING TYPES >BOX COUPLING WAYS EXAMPLES

SUBSTANCE MASS CONSERVATION = STATE EQUATION

C is the concentration of the substance

. .Vol x y z with And at the surfaceat the bottom

0outM . . .in in settlingM C w x y

. settlingC wCu CvC

t x y z

Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas

INTRODUCTION COUPLING TYPES >BOX COUPLING WAYS EXAMPLES

If C is the concentration of a biologic substance,C is not conservative

. settlingC wCu CvCTrend

t x y z

BOX MODEL

ConcentrationTrend term=

Sources – Sinks

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

INTRODUCTION COUPLING TYPES >BOX COUPLING WAYS EXAMPLES

BOX MODEL