OCADSColumn Header Standards for Underway Data
Table 2. Column header abbreviations, their preferred units, and brief descriptions for surface underway based chemical oceanographic data. "N/A" is short for "not applicable". Users can go to the "Resources" tab and click the "Quality Control Flags" collapsible to access the definitions of the quality control flags.
| ABBREVIATION | UNIT | DESCRIPTION |
|---|---|---|
| EXPOCODE | N/A | Expedition code (EXPOCODE) consists of the four-digit International Council for the Exploration of the Sea (ICES) platform code and the date of departure from port (UTC) in YYYYMMDD. |
| Cruise_ID | N/A | Cruise identification |
| Year_UTC | N/A | Calendar year in Coordinated Universal Time (UTC) |
| Month_UTC | N/A | Calendar month in Coordinated Universal Time (UTC) |
| Day_UTC | N/A | Calendar day in Coordinated Universal Time (UTC) |
| Time_UTC | [hh:mm:ss] | Time in the format of hh:mm:ss |
| Yearday_UTC | N/A | Yearday refers to the day number in an annual cycle. (e.g., 12 pm on Jan 1 means Yearday = 1.50, 6 am on Dec 31 means Yearday = 366.25 in a leap year). Two digits after the decimal point are recommended. |
| Latitude | decimal degree | Latitude in decimal degrees North (negative for Southern Hemisphere) |
| Longitude | decimal degree | Longitude in decimal degrees East (negative for Western Hemisphere) |
| Depth | m | Depth in meters |
| SST_ITS90 | degree Celsius | Sea surface temperature (usually intake temperature) |
| SSS_PSS78 | N/A | Sea surface salinity |
| Pressure_ATM | hPa | Sea level atmospheric Pressure |
| Temperature_EQU_ITS90 | degree Celsius | Water temperature recorded in the equilibrator |
| Pressure_EQU | hPa | Pressure inside the headspace of the equilibrator. 1 hPa = 1 mbar. |
| xCO2_EQU | μmol/mol | Mole fraction of carbon dioxide (dry) inside the headspace of the equilibrator |
| xCO2_ATM | μmol/mol | Mole fraction of carbon dioxide (dry) in the atmosphere |
| xCO2_ATM_interpolated | μmol/mol | Interpolated atmospheric xCO2 to match with water analyses time |
| fCO2_SW_SST | μatm | Fugacity of seawater carbon dioxide at SST |
| fCO2_SW_flag | N/A | Quality control flag for fugacity of seawater carbon dioxide |
| fCO2_ATM_interpolated | μatm | Interpolated atmospheric fCO2 |
| dfCO2 | μatm | Delta fCO2 between seawater and atmosphere (fCO2_SW - fCO2_ATM) |
| pH_T_insitu | N/A | pH on total scale at in situ temperature |
| pH_flag | N/A | Quality control flag for pH_T_insitu |
| Oxygen | μmol/kg | Dissolved oxygen measured from sensor |
| Oxygen_flag | N/A | Quality control flag for dissolved oxygen |
| Percent_O2 | N/A | Percent O2 measurement made in equilibrated air |
| Percent_O2_flag | N/A | Quality control flag for Percent_O2 |
| Chl_a | μg/L | Chlorophyll a concentration |
| Chl_a_flag | N/A | Quality control flag Chlorophyll a concentration |
Click here to access the data file (xlsx) example.
* A newly developed program called fCO2_Calc is available to standardize the calculation of partial pressure of carbon dioxide (pCO2) and fugacity of carbon dioxide (fCO2) from molecular ratio (mole fraction) of carbon dioxide in dry air (xCO2) measurements (Credit: Denis Pierrort of NOAA/AOML).
Last modified: 2025-03-31T15:50:56Z
