@article{01e453609b8a4703ac9d7d7769c6e076,
title = "Calculating surface ocean pCO2 from biogeochemical Argo floats equipped with pH: An uncertainty analysis",
abstract = "More than 74 biogeochemical profiling floats that measure water column pH, oxygen, nitrate, fluorescence, and backscattering at 10 day intervals have been deployed throughout the Southern Ocean. Calculating the surface ocean partial pressure of carbon dioxide (pCO2sw) from float pH has uncertainty contributions from the pH sensor, the alkalinity estimate, and carbonate system equilibrium constants, resulting in a relative standard uncertainty in pCO2sw of 2.7% (or 11 µatm at pCO2sw of 400 µatm). The calculated pCO2sw from several floats spanning a range of oceanographic regimes are compared to existing climatologies. In some locations, such as the subantarctic zone, the float data closely match the climatologies, but in the polar Antarctic zone significantly higher pCO2sw are calculated in the wintertime implying a greater air-sea CO2 efflux estimate. Our results based on four representative floats suggest that despite their uncertainty relative to direct measurements, the float data can be used to improve estimates for air-sea carbon flux, as well as to increase knowledge of spatial, seasonal, and interannual variability in this flux.",
keywords = "Southern Ocean, air-sea carbon dioxide flux, biogeochemical floats, carbon budget, pH sensor",
author = "Williams, {N. L.} and Juranek, {L. W.} and Feely, {R. A.} and Johnson, {K. S.} and Sarmiento, {J. L.} and Talley, {L. D.} and Dickson, {A. G.} and Gray, {A. R.} and R. Wanninkhof and Russell, {J. L.} and Riser, {S. C.} and Y. Takeshita",
note = "Funding Information: A snapshot of the quality controlled SOCCOM biogeochemical float data used in this study is available at http://doi.org/10.6075/J0QC01DJ. The float temperature and salinity data used in this project are available at http://doi.org/10.17882/42182 and were made freely available by the International Argo Program and the national programs that contribute to it. Other discrete and underway cruise data used in this study are available at https://cchdo.ucsd.edu and http://cdiac.ornl.gov/oceans. 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, supplemented by NASA (NNX14AP49G). Additionally, we acknowledge support from U.S. Argo through NOAA/JISAO grant NA17RJ1232 to the University of Washington. Logistical support for this project in Antarctic waters was provided by the U.S. National Science Foundation through the U.S. Antarctic Program and the U.S. GO-SHIP program, Australia's CSIRO, and Germany's Alfred Wegener Institute. Richard Feely was supported by the Ocean Observations and Monitoring Division, Climate Program Office, National Oceanic and Atmospheric Administration, U.S. Department of Commerce. Work done at Monterey Bay Aquarium Research Institute was supported by the David and Lucile Packard Foundation. Alison Gray was supported by a NOAA Climate and Global Change postdoctoral fellowship. Nancy Williams is also supported by the ARCS Foundation Oregon Chapter. We would like to thank J. Plant, A. Fassbender, and B. Carter for helpful discussions, and we gratefully acknowledge Are Olsen and an anonymous reviewer for insightful comments that have strengthened this manuscript. This is PMEL contribution number 4547. Publisher Copyright: {\textcopyright}2017. American Geophysical Union. All Rights Reserved.",
year = "2017",
month = mar,
day = "1",
doi = "10.1002/2016GB005541",
language = "English (US)",
volume = "31",
pages = "591--604",
journal = "Global Biogeochemical Cycles",
issn = "0886-6236",
publisher = "American Geophysical Union",
number = "3",
}