Ancillary Measurements

The ancillary measurements used to calculate in situ CO₂ concentrations in the atmospheric and surface seawater samples are sea surface temperature, temperature of seawater in the equilibrator, salinity, and atmospheric pressure. Surface seawater temperature was measured near the bow intake line on most cruises with a thermosalinograph provided by the ship. The temperature of seawater in the equilibrator was measured by mercury thermometer and thermistors. Salinity was taken from the thermosalinograph located near the bow intake line, and atmospheric pressure was recorded hourly from a barometer located on the bridge deck of the ships.