US GO-SHIP Level 1 measurements are core measurements (required with stringent data policy and timeline for submission of data):

• Dissolved inorganic carbon (DIC)
• Total Alkalinity (TAlk)
• pH
• CTD pressure, temperature, salinity (calculated)
• CTD oxygen (sensor)
• Bottle salinity
• Nutrients by standard auto analyzer (NO3/NO2, NO2, PO4, SiO3)
• Nitrate NO3 (calculated)
• Dissolved oxygen
• Chlorofluorocarbons (CFC-11, -12) and SF6
• Dissolved organic carbon
• Total dissolved nitrogen
• Surface underway system (T, S, pCO2)
• ADCP shipboard
• ADCP lowered
• Underway navigation and bathymetry
• Meteorological