A seamless ensemble-based reconstruction of surface ocean pCO2 and air–sea CO2 fluxes over the global coastal and open oceans
We have estimated global air–sea CO 2 fluxes ( fg CO 2 ) from the open ocean to coastal seas. Fluxes and associated uncertainty are computed from an ensemble-based reconstruction of CO 2 sea surface partial pressure ( p CO 2 ) maps trained with gridded data from the Surface Ocean CO 2 Atlas v2020 da...
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ftcopernicus:oai:publications.copernicus.org:bg96663 2023-05-15T15:19:36+02:00 A seamless ensemble-based reconstruction of surface ocean pCO2 and air–sea CO2 fluxes over the global coastal and open oceans Chau, Thi Tuyet Trang Gehlen, Marion Chevallier, Frédéric 2022-02-21 application/pdf https://doi.org/10.5194/bg-19-1087-2022 https://bg.copernicus.org/articles/19/1087/2022/ eng eng doi:10.5194/bg-19-1087-2022 https://bg.copernicus.org/articles/19/1087/2022/ eISSN: 1726-4189 Text 2022 ftcopernicus https://doi.org/10.5194/bg-19-1087-2022 2022-02-28T17:22:17Z We have estimated global air–sea CO 2 fluxes ( fg CO 2 ) from the open ocean to coastal seas. Fluxes and associated uncertainty are computed from an ensemble-based reconstruction of CO 2 sea surface partial pressure ( p CO 2 ) maps trained with gridded data from the Surface Ocean CO 2 Atlas v2020 database. The ensemble mean (which is the best estimate provided by the approach) fits independent data well, and a broad agreement between the spatial distribution of model–data differences and the ensemble standard deviation (which is our model uncertainty estimate) is seen. Ensemble-based uncertainty estimates are denoted by ±1 σ . The space–time-varying uncertainty fields identify oceanic regions where improvements in data reconstruction and extensions of the observational network are needed. Poor reconstructions of p CO 2 are primarily found over the coasts and/or in regions with sparse observations, while fg CO 2 estimates with the largest uncertainty are observed over the open Southern Ocean (44 ∘ S southward), the subpolar regions, the Indian Ocean gyre, and upwelling systems. Our estimate of the global net sink for the period 1985–2019 is 1.643±0.125 PgC yr −1 including 0.150±0.010 PgC yr −1 for the coastal net sink. Among the ocean basins, the Subtropical Pacific (18–49 ∘ N) and the Subpolar Atlantic (49–76 ∘ N) appear to be the strongest CO 2 sinks for the open ocean and the coastal ocean, respectively. Based on mean flux density per unit area, the most intense CO 2 drawdown is, however, observed over the Arctic (76 ∘ N poleward) followed by the Subpolar Atlantic and Subtropical Pacific for both open-ocean and coastal sectors. Reconstruction results also show significant changes in the global annual integral of all open- and coastal-ocean CO 2 fluxes with a growth rate of <math xmlns="http://www.w3.org/1998/Math/MathML" id="M26" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>+</mo><mn mathvariant="normal">0.062</mn><mo>±</mo><mn mathvariant="normal">0.006</mn></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="76pt" height="10pt" class="svg-formula" dspmath="mathimg" md5hash="cc04dd43dbc4d8e7219a1e12606bad01"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-19-1087-2022-ie00001.svg" width="76pt" height="10pt" src="bg-19-1087-2022-ie00001.png"/></svg:svg> PgC yr −2 and a temporal standard deviation of 0.526±0.022 PgC yr −1 over the 35-year period. The link between the large interannual to multi-year variations of the global net sink and the El Niño–Southern Oscillation climate variability is reconfirmed. Text Arctic Southern Ocean Copernicus Publications: E-Journals Arctic Indian Pacific Southern Ocean Biogeosciences 19 4 1087 1109 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
We have estimated global air–sea CO 2 fluxes ( fg CO 2 ) from the open ocean to coastal seas. Fluxes and associated uncertainty are computed from an ensemble-based reconstruction of CO 2 sea surface partial pressure ( p CO 2 ) maps trained with gridded data from the Surface Ocean CO 2 Atlas v2020 database. The ensemble mean (which is the best estimate provided by the approach) fits independent data well, and a broad agreement between the spatial distribution of model–data differences and the ensemble standard deviation (which is our model uncertainty estimate) is seen. Ensemble-based uncertainty estimates are denoted by ±1 σ . The space–time-varying uncertainty fields identify oceanic regions where improvements in data reconstruction and extensions of the observational network are needed. Poor reconstructions of p CO 2 are primarily found over the coasts and/or in regions with sparse observations, while fg CO 2 estimates with the largest uncertainty are observed over the open Southern Ocean (44 ∘ S southward), the subpolar regions, the Indian Ocean gyre, and upwelling systems. Our estimate of the global net sink for the period 1985–2019 is 1.643±0.125 PgC yr −1 including 0.150±0.010 PgC yr −1 for the coastal net sink. Among the ocean basins, the Subtropical Pacific (18–49 ∘ N) and the Subpolar Atlantic (49–76 ∘ N) appear to be the strongest CO 2 sinks for the open ocean and the coastal ocean, respectively. Based on mean flux density per unit area, the most intense CO 2 drawdown is, however, observed over the Arctic (76 ∘ N poleward) followed by the Subpolar Atlantic and Subtropical Pacific for both open-ocean and coastal sectors. Reconstruction results also show significant changes in the global annual integral of all open- and coastal-ocean CO 2 fluxes with a growth rate of <math xmlns="http://www.w3.org/1998/Math/MathML" id="M26" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>+</mo><mn mathvariant="normal">0.062</mn><mo>±</mo><mn mathvariant="normal">0.006</mn></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="76pt" height="10pt" class="svg-formula" dspmath="mathimg" md5hash="cc04dd43dbc4d8e7219a1e12606bad01"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-19-1087-2022-ie00001.svg" width="76pt" height="10pt" src="bg-19-1087-2022-ie00001.png"/></svg:svg> PgC yr −2 and a temporal standard deviation of 0.526±0.022 PgC yr −1 over the 35-year period. The link between the large interannual to multi-year variations of the global net sink and the El Niño–Southern Oscillation climate variability is reconfirmed. |
format |
Text |
author |
Chau, Thi Tuyet Trang Gehlen, Marion Chevallier, Frédéric |
spellingShingle |
Chau, Thi Tuyet Trang Gehlen, Marion Chevallier, Frédéric A seamless ensemble-based reconstruction of surface ocean pCO2 and air–sea CO2 fluxes over the global coastal and open oceans |
author_facet |
Chau, Thi Tuyet Trang Gehlen, Marion Chevallier, Frédéric |
author_sort |
Chau, Thi Tuyet Trang |
title |
A seamless ensemble-based reconstruction of surface ocean pCO2 and air–sea CO2 fluxes over the global coastal and open oceans |
title_short |
A seamless ensemble-based reconstruction of surface ocean pCO2 and air–sea CO2 fluxes over the global coastal and open oceans |
title_full |
A seamless ensemble-based reconstruction of surface ocean pCO2 and air–sea CO2 fluxes over the global coastal and open oceans |
title_fullStr |
A seamless ensemble-based reconstruction of surface ocean pCO2 and air–sea CO2 fluxes over the global coastal and open oceans |
title_full_unstemmed |
A seamless ensemble-based reconstruction of surface ocean pCO2 and air–sea CO2 fluxes over the global coastal and open oceans |
title_sort |
seamless ensemble-based reconstruction of surface ocean pco2 and air–sea co2 fluxes over the global coastal and open oceans |
publishDate |
2022 |
url |
https://doi.org/10.5194/bg-19-1087-2022 https://bg.copernicus.org/articles/19/1087/2022/ |
geographic |
Arctic Indian Pacific Southern Ocean |
geographic_facet |
Arctic Indian Pacific Southern Ocean |
genre |
Arctic Southern Ocean |
genre_facet |
Arctic Southern Ocean |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-19-1087-2022 https://bg.copernicus.org/articles/19/1087/2022/ |
op_doi |
https://doi.org/10.5194/bg-19-1087-2022 |
container_title |
Biogeosciences |
container_volume |
19 |
container_issue |
4 |
container_start_page |
1087 |
op_container_end_page |
1109 |
_version_ |
1766349806416953344 |