Global Synthesis of Air-Sea CO2 Transfer Velocity Estimates From Ship-Based Eddy Covariance Measurements
The air-sea gas transfer velocity (K660) is typically assessed as a function of the 10-m neutral wind speed (U10n), but there remains substantial uncertainty in this relationship. Here K660 of CO2 derived with the eddy covariance (EC) technique from eight datasets (11 research cruises) are reevaluat...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2022-06-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2022.826421/full |
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| author | Mingxi Yang Thomas G. Bell Jean-Raymond Bidlot Byron W. Blomquist Byron W. Blomquist Brian J. Butterworth Brian J. Butterworth Yuanxu Dong Yuanxu Dong Christopher W. Fairall Sebastian Landwehr Christa A. Marandino Scott D. Miller Eric S. Saltzman Alexander Zavarsky |
| author_facet | Mingxi Yang Thomas G. Bell Jean-Raymond Bidlot Byron W. Blomquist Byron W. Blomquist Brian J. Butterworth Brian J. Butterworth Yuanxu Dong Yuanxu Dong Christopher W. Fairall Sebastian Landwehr Christa A. Marandino Scott D. Miller Eric S. Saltzman Alexander Zavarsky |
| author_sort | Mingxi Yang |
| collection | DOAJ |
| description | The air-sea gas transfer velocity (K660) is typically assessed as a function of the 10-m neutral wind speed (U10n), but there remains substantial uncertainty in this relationship. Here K660 of CO2 derived with the eddy covariance (EC) technique from eight datasets (11 research cruises) are reevaluated with consistent consideration of solubility and Schmidt number and inclusion of the ocean cool skin effect. K660 shows an approximately linear dependence with the friction velocity (u*) in moderate winds, with an overall relative standard deviation (relative standard error) of about 20% (7%). The largest relative uncertainty in K660 occurs at low wind speeds, while the largest absolute uncertainty in K660 occurs at high wind speeds. There is an apparent regional variation in the steepness of the K660-u* relationships: North Atlantic ≥ Southern Ocean > other regions (Arctic, Tropics). Accounting for sea state helps to collapse some of this regional variability in K660 using the wave Reynolds number in very large seas and the mean squared slope of the waves in small to moderate seas. The grand average of EC-derived K660(−1.47 + 76.67u*+ 20.48u*2 or 0.36 + 1.203U10n+ 0.167U10n2) is similar at moderate to high winds to widely used dual tracer-based K660 parametrization, but consistently exceeds the dual tracer estimate in low winds, possibly in part due to the chemical enhancement in air-sea CO2 exchange. Combining the grand average of EC-derived K660 with the global distribution of wind speed yields a global average transfer velocity that is comparable with the global radiocarbon (14C) disequilibrium, but is ~20% higher than what is implied by dual tracer parametrizations. This analysis suggests that CO2 fluxes computed using a U10n2 dependence with zero intercept (e.g., dual tracer) are likely underestimated at relatively low wind speeds. |
| first_indexed | 2024-04-12T12:33:46Z |
| format | Article |
| id | doaj.art-17950a097d1f451b81dcf9c31720d51b |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-04-12T12:33:46Z |
| publishDate | 2022-06-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj.art-17950a097d1f451b81dcf9c31720d51b2022-12-22T03:32:56ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452022-06-01910.3389/fmars.2022.826421826421Global Synthesis of Air-Sea CO2 Transfer Velocity Estimates From Ship-Based Eddy Covariance MeasurementsMingxi Yang0Thomas G. Bell1Jean-Raymond Bidlot2Byron W. Blomquist3Byron W. Blomquist4Brian J. Butterworth5Brian J. Butterworth6Yuanxu Dong7Yuanxu Dong8Christopher W. Fairall9Sebastian Landwehr10Christa A. Marandino11Scott D. Miller12Eric S. Saltzman13Alexander Zavarsky14Plymouth Marine Laboratory, Prospect Place, Plymouth, United KingdomPlymouth Marine Laboratory, Prospect Place, Plymouth, United KingdomEuropean Centre for Medium-Range Weather Forecasts, Shinfield Park, Reading, United KingdomCooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, United StatesNational Oceanic and Atmospheric Administration (NOAA) Physical Sciences Laboratory, 325 Broadway, Boulder, CO, United StatesCooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, United StatesNational Oceanic and Atmospheric Administration (NOAA) Physical Sciences Laboratory, 325 Broadway, Boulder, CO, United StatesPlymouth Marine Laboratory, Prospect Place, Plymouth, United KingdomCentre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, United KingdomNational Oceanic and Atmospheric Administration (NOAA) Physical Sciences Laboratory, 325 Broadway, Boulder, CO, United StatesFormerly at School of Physics and Ryan Institute, National University of Ireland Galway, Galway, IrelandGEOMAR Helmholtz Centre for Ocean ResearchKiel, Wischhofstraße 1-3, Kiel, GermanyUniversity at Albany, State University of New York, Albany, NY, United StatesDepartment of Earth System Science, University of California, Irvine, Irvine, CA, United StatesGEOMAR Helmholtz Centre for Ocean ResearchKiel, Wischhofstraße 1-3, Kiel, GermanyThe air-sea gas transfer velocity (K660) is typically assessed as a function of the 10-m neutral wind speed (U10n), but there remains substantial uncertainty in this relationship. Here K660 of CO2 derived with the eddy covariance (EC) technique from eight datasets (11 research cruises) are reevaluated with consistent consideration of solubility and Schmidt number and inclusion of the ocean cool skin effect. K660 shows an approximately linear dependence with the friction velocity (u*) in moderate winds, with an overall relative standard deviation (relative standard error) of about 20% (7%). The largest relative uncertainty in K660 occurs at low wind speeds, while the largest absolute uncertainty in K660 occurs at high wind speeds. There is an apparent regional variation in the steepness of the K660-u* relationships: North Atlantic ≥ Southern Ocean > other regions (Arctic, Tropics). Accounting for sea state helps to collapse some of this regional variability in K660 using the wave Reynolds number in very large seas and the mean squared slope of the waves in small to moderate seas. The grand average of EC-derived K660(−1.47 + 76.67u*+ 20.48u*2 or 0.36 + 1.203U10n+ 0.167U10n2) is similar at moderate to high winds to widely used dual tracer-based K660 parametrization, but consistently exceeds the dual tracer estimate in low winds, possibly in part due to the chemical enhancement in air-sea CO2 exchange. Combining the grand average of EC-derived K660 with the global distribution of wind speed yields a global average transfer velocity that is comparable with the global radiocarbon (14C) disequilibrium, but is ~20% higher than what is implied by dual tracer parametrizations. This analysis suggests that CO2 fluxes computed using a U10n2 dependence with zero intercept (e.g., dual tracer) are likely underestimated at relatively low wind speeds.https://www.frontiersin.org/articles/10.3389/fmars.2022.826421/fullair-sea exchangegas exchangeeddy covariance (EC)CO2transfer velocitywaves |
| spellingShingle | Mingxi Yang Thomas G. Bell Jean-Raymond Bidlot Byron W. Blomquist Byron W. Blomquist Brian J. Butterworth Brian J. Butterworth Yuanxu Dong Yuanxu Dong Christopher W. Fairall Sebastian Landwehr Christa A. Marandino Scott D. Miller Eric S. Saltzman Alexander Zavarsky Global Synthesis of Air-Sea CO2 Transfer Velocity Estimates From Ship-Based Eddy Covariance Measurements Frontiers in Marine Science air-sea exchange gas exchange eddy covariance (EC) CO2 transfer velocity waves |
| title | Global Synthesis of Air-Sea CO2 Transfer Velocity Estimates From Ship-Based Eddy Covariance Measurements |
| title_full | Global Synthesis of Air-Sea CO2 Transfer Velocity Estimates From Ship-Based Eddy Covariance Measurements |
| title_fullStr | Global Synthesis of Air-Sea CO2 Transfer Velocity Estimates From Ship-Based Eddy Covariance Measurements |
| title_full_unstemmed | Global Synthesis of Air-Sea CO2 Transfer Velocity Estimates From Ship-Based Eddy Covariance Measurements |
| title_short | Global Synthesis of Air-Sea CO2 Transfer Velocity Estimates From Ship-Based Eddy Covariance Measurements |
| title_sort | global synthesis of air sea co2 transfer velocity estimates from ship based eddy covariance measurements |
| topic | air-sea exchange gas exchange eddy covariance (EC) CO2 transfer velocity waves |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2022.826421/full |
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