Empirical algorithms to estimate water column pH in the Southern Ocean

• Published in: Geophysical Research Letters
• Main Authors: Williams, N. L., Juranek, L. W., Johnson, K. S., Feely, R. A., Riser, S. C., Talley, L. D., Russell, J. L., Sarmiento, J. L., Wanninkhof, R.
• Other Authors: Univ Arizona, Dept Geosci, College of Earth, Ocean, and Atmospheric Sciences; Oregon State University; Corvallis Oregon USA, Monterey Bay Aquarium Research Institute; Moss Landing California USA, Pacific Marine Environmental Laboratory; National Oceanic and Atmospheric Administration; Seattle Washington USA, School of Oceanography; University of Washington; Seattle Washington USA, Scripps Institution of Oceanography; University of California, San Diego; La Jolla California USA, Department of Geosciences; University of Arizona; Tucson Arizona USA, Program in Atmospheric and Oceanic Sciences; Princeton University; Princeton New Jersey USA, Atlantic Oceanographic and Meteorological Laboratory; National Oceanic and Atmospheric Administration; Miami Florida USA
• Format: Article in Journal/Newspaper
• Language: English
• Published: AMER GEOPHYSICAL UNION 2016
• Subjects: ANTHROPOGENIC CARBON; SEAWATER; CO2; ACIDIFICATION; ALKALINITY; Antarctic; Pacific; Southern Ocean; Antarc*
• Online Access: http://hdl.handle.net/10150/614732; https://doi.org/10.1002/2016GL068539

Empirical algorithms are developed using high-quality GO-SHIP hydrographic measurements of commonly measured parameters (temperature, salinity, pressure, nitrate, and oxygen) that estimate pH in the Pacific sector of the Southern Ocean. The coefficients of determination, R-2, are 0.98 for pH from nitrate (pH(N)) and 0.97 for pH from oxygen (pH(Ox)) with RMS errors of 0.010 and 0.008, respectively. These algorithms are applied to Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) biogeochemical profiling floats, which include novel sensors (pH, nitrate, oxygen, fluorescence, and backscatter). These algorithms are used to estimate pH on floats with no pH sensors and to validate and adjust pH sensor data from floats with pH sensors. The adjusted float data provide, for the first time, seasonal cycles in surface pH on weekly resolution that range from 0.05 to 0.08 on weekly resolution for the Pacific sector of the Southern Ocean. The measurement methods, calibration, and quality control for all discrete bottle data used in this study are available at http://cchdo.ucsd.edu, and all SOCCOM float data are available at http://soccom.princeton.edu/soccomviz.php. This work was sponsored by the U.S. National Science Foundation's Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) Project under the NSF Award PLR-1425989. Logistical support for this project in Antarctic waters was provided by the U.S. National Science Foundation through the U.S. Antarctic Program. Additionally, we acknowledge support from U.S. Argo through NOAA/JISAO grant NA17RJ1232 to the University of Washington. Nancy Williams is also supported by the ARCS Foundation Portland Chapter. This is PMEL contribution 4417. Embargo "Publisher's version/PDF must be used in Institutional Repository 6 months after publication." This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [e-mail].