Ocean Absolute Salinity

Converts practical salinity into absolute salinity (g/kg). The newly calculated variable is included in the same obs space. Note that this requires GSW-Fortran to be included in your build.

Variables used

  • Practical salinity.

  • Pressure (dbar).

Output Variable

  • Absolute Salinity (g/kg). The corresponding observation error, GrossErrorProbability and QC flag data are copied from the input salinity variable if available.

Parameters

  • ocean salinity variable: Practical salinity variable name (default salinity).

  • ocean salinity group: Practical salinity variable group (default ObsValue).

  • ocean pressure variable: Pressure variable name (default waterPressure).

  • ocean pressure group: Pressure variable group (default ObsValue - note that it will be DerivedObsValue if created using OceanDepthToPressure).

  • ocean absolute salinity name: Variable name of output (default absoluteSalinity; created in group DerivedObsValue).

Example yaml block

obs filters:
- filter: Variable Transforms
  Transform: "OceanPracticalSalinityToAbsoluteSalinity"
  ocean pressure group: "DerivedObsValue"

Method

Currently the only method used is from the TEOS-10 GSW toolbox, gsw_SA_from_SP.

Ocean Conservative Temperature

Converts in situ temperature (deg.C), absolute salinity (g/kg) and pressure (dbar) into conservative temperature (deg.C). The newly calculated variable is included in the same obs space. Note that this requires GSW-Fortran to be included in your build.

Variables used

  • Absolute salinity (g/kg).

  • In situ temperature (deg.C).

  • Pressure (dbar).

Output Variable

  • Conservative temperature (deg.C). The corresponding observation error, GrossErrorProbability and QC flag data are copied from the input temperature variable if available.

Parameters

  • ocean salinity variable: Salinity variable name (default absoluteSalinity).

  • ocean salinity group: Salinity variable group (default ObsValue - note that it will be DerivedObsValue if created using OceanPracticalSalinityToAbsoluteSalinity).

  • ocean temperature variable: Temperature variable name (default waterTemperature).

  • ocean temperature group: Temperature variable group (default ObsValue).

  • ocean pressure variable: Pressure variable name (default waterPressure).

  • ocean pressure group: Pressure variable group (default ObsValue - note that it will be DerivedObsValue if created using OceanDepthToPressure).

  • ocean conservative temperature name: Variable name of output (default waterConservativeTemperature; created in group DerivedObsValue).

Example yaml block

obs filters:
- filter: Variable Transforms
  Transform: "OceanTempToConservativeTemp"
  ocean pressure group: "DerivedObsValue"

Method

Currently the only method used is from the TEOS-10 GSW toolbox, gsw_CT_from_t.

Ocean Density

Converts in situ temperature (deg.C), absolute salinity (g/kg) and pressure (dbar) into density (kg/m^3). The newly calculated variable is included in the same obs space. Note that this requires GSW-Fortran to be included in your build.

Variables used

  • Absolute salinity (g/kg).

  • In situ temperature (deg.C).

  • Pressure (dbar).

Output Variable

  • Density (kg/m^3) - absolute rather than anomaly, i.e. 1000 kg/m^3 is not subtracted from it. The corresponding observation error is set to 1.0 (the user should Perform Action: Assign Error if something different is required), QC flag data are set to 0.

Parameters

  • ocean salinity variable: Salinity variable name (default absoluteSalinity).

  • ocean salinity group: Salinity variable group (default ObsValue - note that it will be DerivedObsValue if created using OceanPracticalSalinityToAbsoluteSalinity).

  • ocean temperature variable: Temperature variable name (default waterTemperature).

  • ocean temperature group: Temperature variable group (default ObsValue).

  • ocean pressure variable: Pressure variable name (default waterPressure).

  • ocean pressure group: Pressure variable group (default ObsValue - note that it will be DerivedObsValue if created using OceanDepthToPressure).

  • ocean density variable: Variable name of output (default waterDensity; created in group DerivedObsValue).

Example yaml block

obs filters:
- filter: Variable Transforms
  Transform: "OceanDensity"
  ocean pressure group: "DerivedObsValue"

Method

Currently the only method used is from the TEOS-10 GSW toolbox, gsw_rho_t_exact.

Ocean Potential Temperature

Converts in situ temperature (deg.C), absolute salinity (g/kg) and pressure (dbar) into potential temperature (deg.C). The newly calculated variable is included in the same obs space. Note that this requires GSW-Fortran to be included in your build.

Variables used

  • Absolute salinity (g/kg).

  • In situ temperature (deg.C).

  • Pressure (dbar).

Output Variable

  • Potential temperature (deg.C), i.e. the temperature that a water parcel would have if moved adiabatically from the given pressure to the reference pressure (zero in this case, i.e. the surface). The corresponding observation error data, GrossErrorProbability and QC flag data are copied from the input temperature variable if available.

Parameters

  • ocean salinity variable: Salinity variable name (default absoluteSalinity).

  • ocean salinity group: Salinity variable group (default ObsValue - note that it will be DerivedObsValue if created using OceanPracticalSalinityToAbsoluteSalinity).

  • ocean temperature variable: Temperature variable name (default waterTemperature).

  • ocean temperature group: Temperature variable group (default ObsValue).

  • ocean pressure variable: Pressure variable name (default waterPressure).

  • ocean pressure group: Pressure variable group (default ObsValue - note that it will be DerivedObsValue if created using OceanDepthToPressure).

  • ocean potential temperature name: Variable name of output (default waterPotentialTemperature; created in group DerivedObsValue).

Example yaml block

obs filters:
- filter: Variable Transforms
  Transform: "OceanTempToTheta"
  ocean pressure group: "DerivedObsValue"

Method

Currently the only method used is from the TEOS-10 GSW toolbox, gsw_pt_from_t. Here we assume the reference pressure is zero.

Ocean Pressure

Converts depth (m) to pressure (dbar). The newly calculated variable is included in the same obs space. Note that this requires GSW-Fortran to be included in your build.

Variables used

  • Depth (m), from 0 at surface, increasing positively with depth.

  • Latitude (deg).

Output Variable

  • Pressure (dbar). The corresponding observation error data is set to 1.0 (the user should Perform Action: Assign Error if something different is required) and the QC flag data are set to 0.

Parameters

  • ocean depth variable: Depth coordinate name (default depthBelowWaterSurface).

  • ocean depth group: Depth coordinate group (default MetaData).

  • ocean pressure name: Output pressure coordinate name (default waterPressure; created in group DerivedObsValue).

Example yaml block

obs filters:
- filter: Variable Transforms
  Transform: "OceanDepthToPressure"
  ocean depth group: "DerivedObsValue"
  ocean depth variable: "depthBelowWaterSurface"
  ocean pressure name: "waterPressure"

Method

Currently the only method used is from the TEOS-10 GSW toolbox, gsw_p_from_z. Here we assume the dynamic height anomaly and sea surface geopotential are both zero.