A 44 years ocean circulation hindcast using a 3D model: steric effect in sea level variability

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.

• A 44 years ocean circulation hindcast using a 3D
  model steric effect in sea level variability

M.I. Ferrer, M.G. Sotillo, E. Álvarez-Fanjul, D.
Gomis, P. Oddo, J.M. Baldasano.
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Index

• VANIMEDAT Project Objectives
• Oceanic Model NEMO
• Hindcast configuration
• Validation
• Conclusions

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Project Objectives

• VANIMEDAT project (funded by Ministerio de
  Educación y Ciencia) Sea level decadal and
  interdecadal variability in the Mediterranean
  Sea.
• Direct determination of the steric component from
  a baroclinic model forced by HIPOCAS air-sea
  fluxes.
• Run 44 years (1958-2001) NEMO model using HIPOCAS
  atmospheric forcing.
• Data base used to study variability in the
  Mediterranean Sea and Iberian Atlantic Waters

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Model NEMO

• NEMO (Nucleus for European Modelling of the
  Ocean) is a state-of-the-art modelling framework
  for oceanographic research, operational
  oceanography seasonal forecast and climate
  studies.
• Ocean dynamics NEMO-OPA
• Evolution and reliability of NEMO are organised
  by a European Consortium between
• CNRS (Centre National de la recherque
  scientifique)
• Mercator-Ocean
• UKMO (Met Office)
• NERC (Natural Environment Research Council)
• Website www.nemo-ocean.eu

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Hindcast configuration

• Model domain
• Horizontal res. 1/8º
• Vertical res. 72 levels
• 14ºW-36.25ºE
• 30.25ºN-46ºN
• Initial conditions T/S ORCA model (resolution
  1/4º)
• Global ocean-ice model for a long
  simulation (1958-2004)

Bathymetry (m)
Initial salinity
Initial temperature
Initial temperature
Initial temperature
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Hindcast configuration

• Forcing
• Atmospheric forcing with bulk formula HIPOCAS
  data base
• time resolution hourly
• spatial resolution 0.5º
• Relaxation to surface ORCA salinity
• time resolution monthly files
• spatial resolution 1/4º
• Atlantic damping to salinity and temperature
  (ORCA) in a buffer zone

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Hindcast configuration

• Forcing
• Atmospheric forcing with bulk formula HIPOCAS
  data base
• time resolution hourly
• spatial resolution 0.5º
• Relaxation to surface ORCA salinity
• time resolution monthly files
• spatial resolution 1/4º
• Atlantic damping to salinity and temperature
  (ORCA) in a buffer zone

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Hindcast configuration

• Initial configuration (bathymetry, rivers) from
  INGV (Instituto Nazionale di Geofisica e
  Vulcanologia, Bologna)
• Bulk formulation from INGV
• Linear free surface filtered formulation
• MPI parallel mode
• The 44-years hindcast is running at Marenostrum
  supercomputer located in Barcelona Supercomputing
  Center (BSC)

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Validation

• Validation first period January 1991 to November
  2001
• Time series of surface salinity, temperature.
• RMSE
• Data sets
• AVHRR SST
• Medatlas Climatology
• ORCA model

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Surface Temperature Monthly Mean
Satellite (green) NEMO (black) ORCA (blue)
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Surface Temperature differences
NEMO-Sat (black) ORCA-Sat (blue)
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Surface Salinity Monthly Mean
Medatlas (red) NEMO (black) ORCA (blue)
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RMSE Medatlas Salinity
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Conclusions

• An ocean reanalysis tool based on a 3D baroclinic
  model forced by hourly HIPOCAS data has been
  developed.
• Extensive validation for the period 1991-2001
  show good agreement with data.
• The generated data will be useful to study ocean
  climate variability, upgrading the HIPOCAS
  database.
• The model application is a powerful tool to
  generate future scenarios.