Limitations and Restrictions

Shipboard measurements data published as the TTO preliminary Hydrographic Data Reports Vols. 1-IV are to be used with caution because salinities were calculated using the Practical Salinity Scale of 1978, and densities were determined from the new International Equation of State. The densities differ significantly from those given in GEOSECS reports and these differences should be considered when comparing the two data sets. Shore based measurements of total CO₂ by a gas extraction and manometric procedure were made on a limited number of samples. The revised estimates of total CO₂ provided in the package have been determined from alkalinity and pCO₂ measurements. Any combination of two of the four variables pH, pCO₂, alkalinity, and total CO₂ permits a complete description of the CO₂ system, within the limits of accuracy of the thermodynamic constants required for the calculation, and thus provide excellent checks on the accuracy of individual measurement.