The O2/N2 Ratio and CO2 Airborne Southern Ocean Study

Stephens, B. B.; Long, Matthew C.; Keeling, Ralph F.; Kort, E. A.; Sweeney, Colm; Apel, E. C.; Atlas, Elliot L.; Beaton, Stuart P.; Bent, J. D.; Blake, N. J.; Bresch, James F.; Casey, Joanna Gordon; Daube, Bruce C.; Diao, Minghui; Diaz, Ernesto; Dierssen, Heidi M.; Donets, Valeria; Gao, Bo; Gierach, M. M.; Green, Robert C.; Haag, Justin M.; Hayman, Matthew; Hills, A. J.; Hoecker-Martínez, Martin S.; Honomichl, Shawn; Hornbrook, R. S.; Jensen, J. B.; Li, Rong Rong; McCubbin, Ian B.; McKain, Kathryn; Morgan, Eric J.; Nolte, Scott H.; Powers, Jordan G.; Rainwater, Bryan; Randolph, Kaylan; Reeves, Mike; Schauffler, S.; Smith, Katherine M.; Smith, M. L.; Stith, Jeff; Stossmeister, G.; Toohey, D. W.; Watt, A.

doi:10.1175/bams-d-16-0206.1

Cited by 34 publications

(31 citation statements)

References 61 publications

(57 reference statements)

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“…Other data available in the NRT ObsPack include measurements from the ACT-America (https://act-america.larc. nasa.gov/, last access: 1 January 2019), ORCAS (Stephens et al, 2018;Stephens, 2017) and ATom (Wofsy et al, 2018) campaigns. Both GLOBALVIEW+ and NRT CO 2 measurement compilations may be downloaded in ObsPack format (Masarie et al, 2014) from https://www.esrl.noaa.gov/gmd/ ccgg/obspack/data.php (last access: 15 April 2019).…”

Section: In Situ Co 2 Measurementsmentioning

confidence: 99%

The 2015–2016 carbon cycle as seen from OCO-2 and the global in situ network

et al. 2019

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Abstract. The Orbiting Carbon Observatory-2 has been on orbit since 2014, and its global coverage holds the potential to reveal new information about the carbon cycle through the use of top-down atmospheric inversion methods combined with column average CO2 retrievals. We employ a large ensemble of atmospheric inversions utilizing different transport models, data assimilation techniques, and prior flux distributions in order to quantify the satellite-informed fluxes from OCO-2 Version 7r land observations and their uncertainties at continental scales. Additionally, we use in situ measurements to provide a baseline against which to compare the satellite-constrained results. We find that within the ensemble spread, in situ observations, and satellite retrievals constrain a similar global total carbon sink of 3.7±0.5 PgC yr−1, and 1.5±0.6 PgC yr−1 for global land, for the 2015–2016 annual mean. This agreement breaks down in smaller regions, and we discuss the differences between the experiments. Of particular interest is the difference between the different assimilation constraints in the tropics, with the largest differences occurring in tropical Africa, which could be an indication of the global perturbation from the 2015–2016 El Niño. Evaluation of posterior concentrations using TCCON and aircraft observations gives some limited insight into the quality of the different assimilation constraints, but the lack of such data in the tropics inhibits our ability to make strong conclusions there.

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Section: In Situ Co 2 Measurementsmentioning

confidence: 99%

The 2015–2016 carbon cycle as seen from OCO-2 and the global in situ network

et al. 2019

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“…The domain averaged footprints showed surface influence from a region that stretched westward to 160°W. Using the same model output, Stephens et al () found that 7‐day footprints showed influence from most of the Southern Ocean and parts of the South Pacific, though these influences were small.…”

Section: Resultsmentioning

confidence: 94%

Summertime Atmospheric Boundary Layer Gradients of O₂ and CO₂ over the Southern Ocean

et al. 2019

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We present airborne observations of the vertical gradient of atmospheric oxygen (δ(O2/N2)) and carbon dioxide (CO2) through the atmospheric boundary layer (BL) over the Drake Passage region of the Southern Ocean, during the O2/N2 Ratio and CO2 Airborne Southern Ocean Study, from 15 January to 29 February 2016. Gradients were predominately anticorrelated, with excesses of δ(O2/N2) and depletions of CO2 found within the boundary layer, relative to a mean reference height of 1.7 km. Through analysis of the molar ratio of the gradients (GR), the behavior of other trace gases measured in situ, and modeling experiments with the Community Earth System Model, we found that the main driver of gradients was air‐sea exchange of O2 and CO2 driven by biological processes, more so than solubility effects. An exception to this was in the eastern Drake Passage, where positive GRs were occasionally observed, likely due to the dominance of thermal forcing on the air‐sea flux of both species. GRs were more spatially consistent than the magnitudes of the gradients, suggesting that GRs can provide integrated process constraints over broad spatial scales. Based on the model simulation within a domain bounded by 45°S, 75°S, 100°W, and 45°W, we show that the sampling density of the campaign was such that the observed mean GR (± standard error), −4.0± 0.8 mol O2 per mol CO2, was a reasonable proxy for both the mean GR and the mean molar ratio of air‐sea fluxes of O2 and CO2 during the O2/N2 Ratio and CO2 Airborne Southern Ocean Study.

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“…oceanic circulation. Observations from aircraft-mounted devices also have the potential to increase the coverage of high-resolution air-sea CO 2 and O 2 exchange measurements, together with ocean color and atmospheric data, e.g., the O 2 /N 2 ration and CO 2 Airborne Southern Ocean (ORCAS) study (Stephens et al, 2018).…”

Section: Constraining the Seasonal Carbon Cyclementioning

confidence: 99%

Delivering Sustained, Coordinated, and Integrated Observations of the Southern Ocean for Global Impact

et al. 2019

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Newman et al. The Southern Ocean Observing System time series of key variables, and delivers the greatest impact from data to all key end-users. Although the Southern Ocean remains one of the least-observed ocean regions, enhanced international coordination and advances in autonomous platforms have resulted in progress toward sustained observations of this region. Since 2009, the Southern Ocean community has deployed over 5700 observational platforms south of 40 • S. Large-scale, multi-year or sustained, multidisciplinary efforts have been supported and are now delivering observations of essential variables at space and time scales that enable assessment of changes being observed in Southern Ocean systems. The improved observational coverage, however, is predominantly for the open ocean, encompasses the summer, consists of primarily physical oceanographic variables, and covers surface to 2000 m. Significant gaps remain in observations of the ice-impacted ocean, the sea ice, depths >2000 m, the air-ocean-ice interface, biogeochemical and biological variables, and for seasons other than summer. Addressing these data gaps in a sustained way requires parallel advances in coordination networks, cyberinfrastructure and data management tools, observational platform and sensor technology, twoway platform interrogation and data-transmission technologies, modeling frameworks, intercalibration experiments, and development of internationally agreed sampling standards and requirements of key variables. This paper presents a community statement on the major scientific and observational progress of the last decade, and importantly, an assessment of key priorities for the coming decade, toward achieving the SOOS vision and delivering essential data to all end-users.

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The O2/N2 Ratio and CO2 Airborne Southern Ocean Study

Cited by 34 publications

References 61 publications

The 2015–2016 carbon cycle as seen from OCO-2 and the global in situ network

The 2015–2016 carbon cycle as seen from OCO-2 and the global in situ network

Summertime Atmospheric Boundary Layer Gradients of O₂ and CO₂ over the Southern Ocean

Delivering Sustained, Coordinated, and Integrated Observations of the Southern Ocean for Global Impact

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The O2/N2 Ratio and CO2 Airborne Southern Ocean Study

Cited by 34 publications

References 61 publications

The 2015–2016 carbon cycle as seen from OCO-2 and the global in situ network

The 2015–2016 carbon cycle as seen from OCO-2 and the global in situ network

Summertime Atmospheric Boundary Layer Gradients of O2 and CO2 over the Southern Ocean

Delivering Sustained, Coordinated, and Integrated Observations of the Southern Ocean for Global Impact

Contact Info

Product

Resources

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Summertime Atmospheric Boundary Layer Gradients of O₂ and CO₂ over the Southern Ocean