Calculating surface ocean pCO2 from biogeochemical Argo floats equipped with pH: An uncertainty analysis

N. L. Williams, L. W. Juranek, R. A. Feely, K. S. Johnson, J. L. Sarmiento, L. D. Talley, A. G. Dickson, A. R. Gray, R. Wanninkhof, Joellen Russell, S. C. Riser, Y. Takeshita

Research output: Contribution to journalArticle

33 Citations (Scopus)

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.

Original languageEnglish (US)
Pages (from-to)591-604
Number of pages14
JournalGlobal Biogeochemical Cycles
Volume31
Issue number3
DOIs
StatePublished - Mar 1 2017

Fingerprint

Argo
Uncertainty analysis
uncertainty analysis
sea surface
carbonate system
air
carbon flux
partial pressure
Fluxes
alkalinity
pH sensors
fluorescence
carbon dioxide
water column
Carbonates
Equilibrium constants
Backscattering
Alkalinity
nitrate
sensor

Keywords

  • air-sea carbon dioxide flux
  • biogeochemical floats
  • carbon budget
  • pH sensor
  • Southern Ocean

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Environmental Science(all)
  • Atmospheric Science

Cite this

Williams, N. L., Juranek, L. W., Feely, R. A., Johnson, K. S., Sarmiento, J. L., Talley, L. D., ... Takeshita, Y. (2017). Calculating surface ocean pCO2 from biogeochemical Argo floats equipped with pH: An uncertainty analysis. Global Biogeochemical Cycles, 31(3), 591-604. https://doi.org/10.1002/2016GB005541

Calculating surface ocean pCO2 from biogeochemical Argo floats equipped with pH : An uncertainty analysis. / Williams, N. L.; Juranek, L. W.; Feely, R. A.; Johnson, K. S.; Sarmiento, J. L.; Talley, L. D.; Dickson, A. G.; Gray, A. R.; Wanninkhof, R.; Russell, Joellen; Riser, S. C.; Takeshita, Y.

In: Global Biogeochemical Cycles, Vol. 31, No. 3, 01.03.2017, p. 591-604.

Research output: Contribution to journalArticle

Williams, NL, Juranek, LW, Feely, RA, Johnson, KS, Sarmiento, JL, Talley, LD, Dickson, AG, Gray, AR, Wanninkhof, R, Russell, J, Riser, SC & Takeshita, Y 2017, 'Calculating surface ocean pCO2 from biogeochemical Argo floats equipped with pH: An uncertainty analysis', Global Biogeochemical Cycles, vol. 31, no. 3, pp. 591-604. https://doi.org/10.1002/2016GB005541
Williams, N. L. ; Juranek, L. W. ; Feely, R. A. ; Johnson, K. S. ; Sarmiento, J. L. ; Talley, L. D. ; Dickson, A. G. ; Gray, A. R. ; Wanninkhof, R. ; Russell, Joellen ; Riser, S. C. ; Takeshita, Y. / Calculating surface ocean pCO2 from biogeochemical Argo floats equipped with pH : An uncertainty analysis. In: Global Biogeochemical Cycles. 2017 ; Vol. 31, No. 3. pp. 591-604.
@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 = "air-sea carbon dioxide flux, biogeochemical floats, carbon budget, pH sensor, Southern Ocean",
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 Joellen Russell and Riser, {S. C.} and Y. Takeshita",
year = "2017",
month = "3",
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",

}

TY - JOUR

T1 - Calculating surface ocean pCO2 from biogeochemical Argo floats equipped with pH

T2 - An uncertainty analysis

AU - Williams, N. L.

AU - Juranek, L. W.

AU - Feely, R. A.

AU - Johnson, K. S.

AU - Sarmiento, J. L.

AU - Talley, L. D.

AU - Dickson, A. G.

AU - Gray, A. R.

AU - Wanninkhof, R.

AU - Russell, Joellen

AU - Riser, S. C.

AU - Takeshita, Y.

PY - 2017/3/1

Y1 - 2017/3/1

N2 - 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.

AB - 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.

KW - air-sea carbon dioxide flux

KW - biogeochemical floats

KW - carbon budget

KW - pH sensor

KW - Southern Ocean

UR - http://www.scopus.com/inward/record.url?scp=85017338740&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85017338740&partnerID=8YFLogxK

U2 - 10.1002/2016GB005541

DO - 10.1002/2016GB005541

M3 - Article

AN - SCOPUS:85017338740

VL - 31

SP - 591

EP - 604

JO - Global Biogeochemical Cycles

JF - Global Biogeochemical Cycles

SN - 0886-6236

IS - 3

ER -