Estimating p(CO2) from pH measurements

A recent article is now available as an accepted article (as open access) in Journal of Geophysical Research: “Assessment of Autonomous pH Measurements for Determining Surface Seawater Partial Pressure of CO2” ( by Yuichiro Takeshita, Kenneth S. Johnson, Todd R. Martz, Josh N. Plant & Jorge Sarmiento.

This article compares underway measurements of surface seawater p(CO2) with the p(CO2) calculated from underway pH measurements obtained using a DuraFET pH sensor. The overall conclusion of this article is that it is possible to track spatiotemporal variability in p(CO2) using measured pH and estimated alkalinity (using a product such as LIAR).

It also provides significant information about the contributions of a variety of input data – including calibrations  – to the ultimate degree of agreement between measured and estimated p(CO2), though few of these are highly important if variability is the only desired information.