Preliminary%20results%20from%20the%20oceanic%20component%20of%20the%20integrated%20earth%20system%20model%20of%20Kyousei2

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Preliminary results from the oceanic component of
the integrated earth system model of Kyousei2

• Michio KAWAMIYA
• Chisato YOSHIKAWA
• Maki NOGUCHI
• Taroh MATSUNO
• Frontier Research System for Global Change,
• Yokohama, Japan

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• At the last steering committee meeting
• Results from a flying leap experiment
• 5 months later ( This talk)
• Performance check
• Sensitivity to surface forcing
• Projection of future CO2 uptake by the ocean
• Incorporation into our coupled model (MIROC)
• Schedule

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Model outline
OGCM Code COCO3.4 (Hasumi, 2000)
based on primitive equations Resolution 1 deg. X
1. deg. 54 vertical levels
(20 levels for the upper 100m)
Biological model Nitrogen based, 4-compartment
model by Oschlies Garcon (1998) modified
by Oschlies (2001) Carbonate system is
incorporated following the OCMIP protocol.
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Comparative study between model-derived and
reanalysis forcing fields (preparation for a
global warming experiment)

• Forcing fields (SST, P-E, wind stress, solar
  radiation) from
• OMIP data (ECMWF reanalysis)
• CCSR/NIES coupled model output
• Initial conditions
• T, S results from an OMIP experiment
• Nitrate World Ocean Atlas 94
• TCO2, Alkalinity results from an OCMIP
  experiment
• Other biological variables constant (0.1
  mmol/m3)
• Spin-up 20 years

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Results
Surf. Chl.
Nitrate
Obs.
Reanalysis
Model-derived
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Nutrient trap along the coast of Peru--
Reanalysis data are less realistic? --
Wind stress
Surf. Nitrate
W along the 15S
Reanalysis
Model-derived
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Nitrate distribution in the Southern Ocean
Nitrate Reanalysis
Nitrate Model-derived
Ekman W Reanalysis
Ekman W Model-derived
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Nitrate distribution in the Southern Ocean (2)
Mixed layer depth
Nitrate
WOA
Reanalysis
Model-derived
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Nutrient distribution in the Southern Ocean (3)
P-E
SSS
WOA
Reanalysis
Model-derived
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Air-sea exchange of CO2
Obs.(Takahashi et al.,1999)
Reanalysis
Model-derived
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Summary of the difference

• Nutrient trapping off Peru due to strong coastal
  upwelling under the OMIP forcing
• Low surface nitrate in the Southern Ocean under
  the model-derived forcing due to shallow mixed
  layer
• The above difference is not reflected in the
  air-sea CO2 exchange field because of differences
  in the processes governing the surface
  concentrations of nitrate and fCO2

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Earlier estimates of future uptake of
anthropogenic CO2 by the ocean
IPCC TAR
OCMIP type models simple representation of the
biological pump
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Time evolution of atmospheric CO2
Gradual, linear increase up until 1990, then
1/year increase
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Air-sea exchange of CO2
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Summary of the performance check

• The experiments forced by reanalysis and
  model-derived data provide similar results
  regarding air-sea CO2 exchange.
• The current and future ocean uptakes of CO2
  estimate by the model are consistent with earlier
  results from models with simpler representation
  of the pelagic ecosystem.
• Apparently, no bug. Go for it!
• First results from a coupled carbon cycle model
  are expected early next year.

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Carbon cycle model now incorporated in our
coupled model
(T42L20 for atmosphere, (0.5-1.4)x1.4 for ocean)
Chlorophyll
Nitrate
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Project Schedule
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Participation in C4MIP

• Coupled Climate-Carbon Cycle Model
  Intercomparison Project (IGBP/GAIM)
• Phase 1 (2004) Emphasis on terrestrial carbon
  cycle models
• Phase 2 (2005) Full coupled carbon cycle models