physical and biogeochemical coupled modelling
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Physical and Biogeochemical Coupled Modelling. Presented by Christel PINAZO Mediterranean University Oceanographic Center of Marseille Physical & Biogeochemical Oceanographic Laboratory. - PowerPoint PPT PresentationTRANSCRIPT
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
COUPLING TYPES
Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas
INTRODUCTION COUPLING TYPES >FINE COUPLING WAYS EXAMPLES
THE STUDY SITE COULD BE SPATIALLY DESCRIBED BY FINE MESH GRID IN
1D, 2D OR 3D
COUPLING TYPES
Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas
INTRODUCTION COUPLING TYPES >FINE COUPLING WAYS EXAMPLES
TO CALCULATE THE VARIATION OF BIOGEOCHEMICAL CONCENTRATIONS :
- EQUATION OF TEMPERATURE VARIATION OF THE HYDRODYNAMIC MODEL
?t
C
Time
evolution
COUPLING TYPES
Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas
INTRODUCTION COUPLING TYPES >FINE COUPLING WAYS EXAMPLES
1D FINE GRID MODEL (VERTICAL)
SEDIMENT
z=-h
z=0
z
Trendz
CK
zz
Cww
t
Czsettling
Vertical eddy
diffusivity Vertical
advectionSettlingVelocity
ConcentrationTrend term=
Sources – Sinks
COUPLING TYPES
Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas
INTRODUCTION COUPLING TYPES >FINE COUPLING WAYS EXAMPLES
ADVANTAGES:
•FINE DISCRETISATION ONLY ALONG VERTICAL AXIS
•SIMULATION OF VERTICAL EDDY DIFFUSIVITY (MIXED LAYER)
AND UP OR DOWNWELLING PHENOMENA
•RELATIVE SHORT COMPUTATIONAL TIME
•LONG SIMULATION OF SEASONS OR YEARS
DISADVANTAGES:
•NOT SIMULATE HORIZONTAL ADVECTION
•NOT SIMULATE CORIOLIS EFFECT
1D FINE GRID MODEL (VERTICAL)
COUPLING TYPES
Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas
INTRODUCTION COUPLING TYPES >FINE COUPLING WAYS EXAMPLES
2D FINE GRID MODEL (HORIZONTAL)depth-integrating Navier-Stokes equations
O x
y
x y
DC DC DC DC DCU V K K Trend
t x y x x y y
Time evolution
Horizontal advection
Horizontal eddy
diffusivity
ConcentrationTrend term=
Sources – Sinks
COUPLING TYPES
Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas
INTRODUCTION COUPLING TYPES >FINE COUPLING WAYS EXAMPLES
ADVANTAGES:
•DISCRETISATION ONLY ALONG HORIZONTAL AXES
•SIMULATION OF HORIZONTAL ADVECTION AND DIFFUSIVITY
•SIMULATION OF CORIOLIS EFFECT
•MEAN COMPUTATIONAL TIME
•SIMULATION OF MONTHS OR SEASONS
DISADVANTAGES:
•NOT SIMULATE VERTICAL EDDY DIFFUSIVITY (MIXED LAYER)
•NOT SIMULATE UP OR DOWNWELLING PHENOMENA
•NOT SIMULATE SEVERAL-LAYERS
2D FINE GRID MODEL (HORIZONTAL)
COUPLING TYPES
Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas
INTRODUCTION COUPLING TYPES >FINE COUPLING WAYS EXAMPLES
3D FINE GRID MODELNavier-Stokes equations
Trendz
CK
zy
CK
yx
CK
xz
Cw
y
Cv
x
Cu
t
Czyx
Time
evolution 3D
advection3D eddy
diffusivity
ConcentrationTrend term=
Sources – Sinks
O x
y
z
COUPLING TYPES
Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas
INTRODUCTION COUPLING TYPES >FINE COUPLING WAYS EXAMPLES
ADVANTAGES:
•FINE DISCRETISATION ALONG THE 3D AXES
•SIMULATION OF ALL THE MAIN PHENOMENA
DISADVANTAGES:
•RELATIVE LONG COMPUTATIONAL TIME
•SHORT SIMULATION OF FORTNIGTH TO MONTHS
3D FINE GRID 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
COUPLING WAYS
Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas
INTRODUCTION COUPLING TYPES COUPLING WAYS EXAMPLES
2DIFFERENT COUPLING WAYS :
- OFF-LINE : 2 SEPARATED RUNS WITH PHYSICAL FORCING CONDITIONS STORED IN FILES
- ON-LINE : DIRECT AND DYNAMIC COUPLING IN 1 RUN
• 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
OFF-LINE COUPLING
Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas
INTRODUCTION COUPLING TYPES COUPLING WAYS>OFF-LINE EXAMPLES
dt= 600 s
HydrodynamicModel
MARS 3D
WindTide
Physical Forcing Variables :
CurrentsEddy diffusivity
Surface elevation…
Irradiance River inputs Wastewater inputs
EcologicalModelEco3M
dt= 1 hour
dt= 1200 sEcological
trends
Physical Forcing
dt = 50 s
Spatial and temporal evolution
Of biogeochemical variables
AdvectionDiffusion
Biogeochemicalvariables
DIRECT AND DYNAMIC COUPLING
Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas
INTRODUCTION COUPLING TYPES COUPLING WAYS>ON-LINE EXAMPLES
Irradiance River inputs Wastewater inputs
EcologicalModel
dt= 1 hour dt= 1200 s
Ecological trends
dt= 600 s
HydrodynamicModel
WindTide
Physical Variables :Currents
Surface elevation…
dt= 50 s
dt = 50 s
AdvectionDiffusionvariables
bio
Spatial and temporal evolutionOf biogeochemical variables
EXAMPLES
Regional Advanced School on Physical and Mathematical Tools for the study of Marine Processes of Coastal Areas
INTRODUCTION COUPLING TYPES COUPLING WAYS EXAMPLES
3D coupled physical and biogeochemical Modelling
Study of ecosystem functioningOf the SW lagoon of New Caledonia
Study site description
Nord
West wind
Trade winds
Study site
Study Site
0
60
120
180
240
300
360
4/4 5/6 6/8 7/10 8/12 8/2 11/4
Win
d d
irection 3
60 °
0
8
16
4/4 5/6 6/8 7/10 8/12 8/2 11/4
win
d s
peed m
.s-1
Vite
sse,
m s
-1D
irect
ion,
360
°
Data from PhD thesis S. Jacquet (2005)
Wind measurements (îlot Maître)Dumbéa river Inputs
0
20
40
60
80
100
120
140
160
180
03/4 23/5 12/7 31/8 20/10 09/12
Déb
it,
m3
s-1
Dé
bit,
m3 s
-1
High short-term variability of meteorological forcings
Low seasonal variability
Study site
Model description
horizontal mesh grid: 500m
Nb horizontal cells: 340*90
10 vertical sigma levels
Forcings : wind, tides
Mars3D
IFREMER-IRD (P. DOUILLET)
Ecological Model:170*90
Horizontal cells
Physical Modelling
ECO3M
Surface currents:Trade winds 8 m s-1
NOUM
ÉA
Physical Modelling
Current Model
• C and N Cycles
• 12 variables
• Zooplankton = « forcing function »
• Eco3M tool
Ecological Modelling
Phytoplankton biomass measurements
Chl.a
Phytoplankton biomass modelling
Carbon Nitrogen ….?
• Constant ratio Carbon : Chlorophyll a
• Chl.a : diagnostic variable calculated from other state variables
• Chl.a : Dynamic state variable
But: /molCgChl. 96.0Chl.
12.0 aC
a
Faure et a (2006)
Ecological Modelling
Irradiance River inputs Wastewater inputs
EcologicalModelEco3M(LOB)
dt= 1 hour dt= 1200 s
Ecological trends
dt= 600 sHydrodynamic
ModelMARS 3D
(IFREMER-IRD)
WindTide
Physical Variables :Currents
Surface elevation…
dt= 50 s
dt = 50 s
AdvectionDiffusionvariables
bio
Spatial and temporal evolutionOf biogeochemical variables
Dynamic coupling between the 2 models
Model results
Irradiance
Débit des rivières
Vent
0
50
100
150
200
250
300
350
18/06 23/06 28/06 03/07 08/07 13/07 18/07 23/07 28/07 02/08 07/08 12/08
Riv
er F
low
m3
s-1
Dumbéa RiverCoulée RiverPirogues River
Measured forcings
Field measurements : HIVER 2003
Realistic Simulation
Chla, µg l-1
19 June
3 July
Weak Trade winds Weak West wind
Realistic Simulation : HIVER 2003, 2D Results
Chla, µg l-1
3 July
15 July
West wind Trade Winds
Realistic Simulation : HIVER 2003, 2D Results
Chla, µg l-1
15 July
26 July
Trade Winds and rainfall
Realistic Simulation : HIVER 2003, 2D Results
Chla, µg l-1
26 July
7 August
West wind Trade winds
Realistic Simulation : HIVER 2003, 2D Results