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 ObsError is set to 1.0 (the user should Perform Action: Assign Error if something different is required), QCFlags are set to 0, and GrossErrorProbability initialised to all missing.

Parameters

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

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

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

Example yaml block

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

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.

Ocean Potential Temperature

Converts temperature (deg.C), 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 ObsError, GrossErrorProbability and QCFlags are the same as those of the input temperature variable.

Parameters

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

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

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

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

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

  • 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 ocean_potential_temperature; 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 Density

Converts temperature (deg.C), 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 ObsError is set to 1.0 (the user should Perform Action: Assign Error if something different is required), QCFlags are set to 0, and GrossErrorProbability initialised to all missing.

Parameters

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

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

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

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

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

  • 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 ocean_density; 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.