The SIO O 2 Program: Constraints on Long-term Carbon Cycle Changes - - PowerPoint PPT Presentation

NOAA GMD Annual Conference | May 2019

The SIO O2 Program: Constraints on Long-term Carbon Cycle Changes Through Measurements of Atmospheric Oxygen

Eric J. Morgan1, Cindy Nevison2, Manfredi Manizza1, and Ralph Keeling1

1Scripps Institution of Oceanography, University of California San Diego, La Jolla CA, USA 2University of Colorado/INSTAAR, Boulder CO, USA

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The SIO O2 Program Flask Network

1990 1995 2000 2005 2010 2015 2020 δ(O2/N2) [per meg]

• 3000
• 2500
• 2000
• 1500
• 1000
• 500

1990 1995 2000 2005 2010 2015 2020 150 200 250 300 350 400 CO2 [ppm] 2 / 14

Global Carbon Budget δ(O2/N2) = (O2/N2)sample (O2/N2)ref − 1

• × 106

APO = δ(O2/N2) + αlnd XO2 (CO2 − 350)

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Global Carbon Budget

350 365 380 395 410 425 440 455 −1050 −950 −850 −750 −650 −550 −450 −350 −250 −150 −50 CO2 [ppm] δ(O2/N2) [per meg]

Ocean uptake uptake Land Atmospheric increase Fossil fuel emissions

1991 − 2017

∆CO2 = F − O − L ∆O2 = −αFF+αLL+Zeff

∆CO2 = atmospheric CO2 ∆O2 = atmospheric O2 F = Fossil fuel emissions O = Net ocean sink L = Net land sink αlnd = stoichiometry of terrestrial exchange αF = stoichiometry of FF burning Zeff = ocean outgassing of O2

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Global Carbon Budget: Inputs

INPUTS

• ∆δ(O2/N2) from SIO O2 Program
• ∆CO2 from SIO O2 Program and NOAA
• F from GCP (CDIAC/BP)
• Zeff from NOAA/NCEI ocean heat content

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Global Carbon Budget: Inputs

2 4 6 8 10

Fossil fuel emissions (PgC yr−1)

1990 1995 2000 2005 2010 2015

gas liquid solid cement gasflaring Total Preliminary data

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Global Carbon Budget: Inputs

Ocean heat content (ZJ) 50 100 150 200 1990−1999 2000−2009 2010−2017 Zeff (1013 mol yr−1) 2 4 6 8 10 1990 1995 2000 2005 2010 2015

Zeff =

• γO2 − XO2

XN2 γN2

• Q + ZatmD

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Global Carbon Budget: Results

2±0.6 (32%) 1.1±0.6 (18%) 3.1±0.3 (50%) 2.6±0.8 (34%) 1.1±0.9 (15%) 4±0.3 (51%) 3.1±1.3 (33%) 1.5±1.3 (15%) 5±0.3 (52%)

1990 2000 2010 2018 2 4 6 8 10 CO2 Flux (PgC yr−1) Atmosphere Land Ocean

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Global Carbon Budget: Comparisons to Other Estimates

1990−1999 2000−2009 2010−2017 1 2 3 4 5 This Study GCP 2018 DeVries 2014 (OCIM) Ocean sink (PgCyr−1) 1990−1999 2000−2009 2010−2017 1 2 3 Land sink (PgCyr−1) 9 / 14

APO and the Southern Annular Mode

Jan Mar May Jul Sep Nov Jan −40 −20 20 40 Detrended δAPO (per meg)

Cape Grim Observatory (CGO), 1991−2018

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APO and the Southern Annular Mode

PSA CGO SAM Detrended August δAPO (per meg) −40 −30 −20 −10 2 1 −1 −2 1993 1998 2003 2008 2013 2018 SAM Index (reversed axis)

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APO and the Southern Annular Mode

PSA CGO SAM FAPO 40−60S Detrended August δAPO (per meg) −40 −30 −20 −10 −19 −17 −15 −13 FAPO (mol m−2 yr−1) 2 1 −1 −2 1993 1998 2003 2008 2013 2018 SAM Index (reversed axis)

FAP O is inferred flux of APO from global atmospheric inversion of SIO data, using the Jena inversion scheme. Data courtesy of C. R¨

• denbeck of MPI-BGC.

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Summary

• δ(O2/N2) and CO2-based carbon budgets can constrain

the land and ocean uptake over decadal time scales

• These data suggest an increasing ocean sink over the

1990–2017 period

• Small increase in land sink, but not well resolved given

uncertainty

• Stations PSA and CGO show wintertime correlations of

APO with the Southern Annular Mode

• Evidence suggests this is related to Southern Ocean

ventilation

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Supplemental: Global Carbon Budget Global carbon budget terms, with αlnd = 1.1

Term Symbol Unit 1990–1999 2000–2009 2010–2017 CO2 trend ∆CO2 ppm yr−1 1.5 ± 0.1 1.9 ± 0.1 2.3 ± 0.1 APO trend ∆APO per meg yr−1 −8.0 ± 0.9 −10 ± 2.0 −12 ± 3 Ocean O2 outgassing Zeff 1013 mol yr−1 4.1 ± 3 5.2 ± 3 6.6 ± 3 OR of fossil fuels αF mol mol−1 1.40 ± 0.06 1.39 ± 0.06 1.37 ± 0.06 Fossil fuel emissions F Pg C yr−1 6.3 ± 0.07 7.8 ± 0.1 9.6 ± 0.1 Atmospheric CO2 ACO2 Pg C yr−1 3.2 ± 0.3 4.0 ± 0.3 5.0 ± 0.3 Net land sink L Pg C yr−1 1.1 ± 0.6 1.2 ± 0.9 1.5 ± 1.3 Net ocean sink O Pg C yr−1 2.0 ± 0.6 2.6 ± 0.8 3.1 ± 1.3 14 / 14