Underway pCO2 Data File Format

(Focuses on results from underway easurement systems.)

I. REQUIRED ELEMENTS

Measured atmospheric information

  • Date / Time of Measurement (UTC)
  • Position of measurement
    • Latitude in decimal degrees (North is positive, South is negative)
    • Longitude in decimal degrees (East is positive, West is negative)
  • Mole fraction of CO2 in ambient atmosphere (µmol/mol in dry air)
  • Atmospheric pressure at sea-surface pressure (hPa)

Measured seawater information

  • Date / Time of Measurement (UTC)
  • Position of measurement
    • Latitude in decimal degrees (North is positive, South is negative)
    • Longitude in decimal degrees (East is positive, West is negative)
  • Mole fraction of CO2 in air from equilibrator (µmol/mol)
  • Mole fraction of of H2O in air from equilibrator (µmol/mol)
  • Pressure of equilibration = the pressure in the equilibration vessel (hPa)
  • Temperature of equilibration = the temperature of the seawater in equilibrator at the time of equilibration (°C)
  • Sea surface temperature (in situ) (°C)
  • Sea surface salinity (in situ)

II. DERIVED PARAMETERS

Atmosphere

  • x(CO2) value for the ambient atmosphere (µmol/mol in dry air); interpolated to match the date/time/position of the seawater information in this section

Seawater

  • f(CO2) for air in equilibrium with seawater at sea surface temperature (µatm). Note: the air will be at 100% humidity
  • p(CO2) for air in equilibrium with seawater at sea surface temperature (µatm). Note: the air will be at 100% humidity
  • x(CO2) for air in equilibrium with the seawater at sea surface temperature and 1013.25 hPa applied pressure (expressed as µmol/mol in dry air)

III. OPTIONAL ANCILLARY INFORMATION

  • Quality flags
  • Detailed Ships Heading Information
  • Other measurements (chemical, physical, meteorological)

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