Assessment of Global Ocean Biogeochemistry Models for Ocean Carbon Sink Estimates in RECCAP2 and Recommendations for Future Studies
Abstract The ocean is a major carbon sink and takes up 25%–30% of the anthropogenically emitted CO2. A state‐of‐the‐art method to quantify this sink are global ocean biogeochemistry models (GOBMs), but their simulated CO2 uptake differs between models and is systematically lower than estimates based...
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| Format: | Article |
| Language: | English |
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American Geophysical Union (AGU)
2024-03-01
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| Series: | Journal of Advances in Modeling Earth Systems |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2023MS003840 |
| _version_ | 1797222038281125888 |
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| author | Jens Terhaar Nadine Goris Jens D. Müller Tim DeVries Nicolas Gruber Judith Hauck Fiz F. Perez Roland Séférian |
| author_facet | Jens Terhaar Nadine Goris Jens D. Müller Tim DeVries Nicolas Gruber Judith Hauck Fiz F. Perez Roland Séférian |
| author_sort | Jens Terhaar |
| collection | DOAJ |
| description | Abstract The ocean is a major carbon sink and takes up 25%–30% of the anthropogenically emitted CO2. A state‐of‐the‐art method to quantify this sink are global ocean biogeochemistry models (GOBMs), but their simulated CO2 uptake differs between models and is systematically lower than estimates based on statistical methods using surface ocean pCO2 and interior ocean measurements. Here, we provide an in‐depth evaluation of ocean carbon sink estimates from 1980 to 2018 from a GOBM ensemble. As sources of inter‐model differences and ensemble‐mean biases our study identifies (a) the model setup, such as the length of the spin‐up, the starting date of the simulation, and carbon fluxes from rivers and into sediments, (b) the simulated ocean circulation, such as Atlantic Meridional Overturning Circulation and Southern Ocean mode and intermediate water formation, and (c) the simulated oceanic buffer capacity. Our analysis suggests that a late starting date and biases in the ocean circulation cause a too low anthropogenic CO2 uptake across the GOBM ensemble. Surface ocean biogeochemistry biases might also cause simulated anthropogenic fluxes to be too low, but the current setup prevents a robust assessment. For simulations of the ocean carbon sink, we recommend in the short‐term to (a) start simulations at a common date before the industrialization and the associated atmospheric CO2 increase, (b) conduct a sufficiently long spin‐up such that the GOBMs reach steady‐state, and (c) provide key metrics for circulation, biogeochemistry, and the land‐ocean interface. In the long‐term, we recommend improving the representation of these metrics in the GOBMs. |
| first_indexed | 2024-04-24T13:14:58Z |
| format | Article |
| id | doaj.art-609e64f9a8084a4880e86c000e95a638 |
| institution | Directory Open Access Journal |
| issn | 1942-2466 |
| language | English |
| last_indexed | 2024-04-24T13:14:58Z |
| publishDate | 2024-03-01 |
| publisher | American Geophysical Union (AGU) |
| record_format | Article |
| series | Journal of Advances in Modeling Earth Systems |
| spelling | doaj.art-609e64f9a8084a4880e86c000e95a6382024-04-04T21:25:34ZengAmerican Geophysical Union (AGU)Journal of Advances in Modeling Earth Systems1942-24662024-03-01163n/an/a10.1029/2023MS003840Assessment of Global Ocean Biogeochemistry Models for Ocean Carbon Sink Estimates in RECCAP2 and Recommendations for Future StudiesJens Terhaar0Nadine Goris1Jens D. Müller2Tim DeVries3Nicolas Gruber4Judith Hauck5Fiz F. Perez6Roland Séférian7Department of Marine Chemistry and Geochemistry Woods Hole Oceanographic Institution Woods Hole MA USANORCE Climate & Environment Bjerknes Centre for Climate Research Bergen NorwayEnvironmental Physics Institute of Biogeochemistry and Pollutant Dynamics ETH Zurich Zürich SwitzerlandDepartment of Geography University of California, Santa Barbara Santa Barbara CA USAEnvironmental Physics Institute of Biogeochemistry and Pollutant Dynamics ETH Zurich Zürich SwitzerlandAlfred‐Wegener‐Institut Helmholtz‐Zentrum für Polar‐ und Meeresforschung Bremerhaven GermanyInstituto de Investigaciones Marinas (IIM) CSIC Vigo SpainCNRM (Université de Toulouse, Météo‐France, CNRS) Toulouse FranceAbstract The ocean is a major carbon sink and takes up 25%–30% of the anthropogenically emitted CO2. A state‐of‐the‐art method to quantify this sink are global ocean biogeochemistry models (GOBMs), but their simulated CO2 uptake differs between models and is systematically lower than estimates based on statistical methods using surface ocean pCO2 and interior ocean measurements. Here, we provide an in‐depth evaluation of ocean carbon sink estimates from 1980 to 2018 from a GOBM ensemble. As sources of inter‐model differences and ensemble‐mean biases our study identifies (a) the model setup, such as the length of the spin‐up, the starting date of the simulation, and carbon fluxes from rivers and into sediments, (b) the simulated ocean circulation, such as Atlantic Meridional Overturning Circulation and Southern Ocean mode and intermediate water formation, and (c) the simulated oceanic buffer capacity. Our analysis suggests that a late starting date and biases in the ocean circulation cause a too low anthropogenic CO2 uptake across the GOBM ensemble. Surface ocean biogeochemistry biases might also cause simulated anthropogenic fluxes to be too low, but the current setup prevents a robust assessment. For simulations of the ocean carbon sink, we recommend in the short‐term to (a) start simulations at a common date before the industrialization and the associated atmospheric CO2 increase, (b) conduct a sufficiently long spin‐up such that the GOBMs reach steady‐state, and (c) provide key metrics for circulation, biogeochemistry, and the land‐ocean interface. In the long‐term, we recommend improving the representation of these metrics in the GOBMs.https://doi.org/10.1029/2023MS003840ocean biogeochemical modelingocean carbon sinkcarbon cycle |
| spellingShingle | Jens Terhaar Nadine Goris Jens D. Müller Tim DeVries Nicolas Gruber Judith Hauck Fiz F. Perez Roland Séférian Assessment of Global Ocean Biogeochemistry Models for Ocean Carbon Sink Estimates in RECCAP2 and Recommendations for Future Studies Journal of Advances in Modeling Earth Systems ocean biogeochemical modeling ocean carbon sink carbon cycle |
| title | Assessment of Global Ocean Biogeochemistry Models for Ocean Carbon Sink Estimates in RECCAP2 and Recommendations for Future Studies |
| title_full | Assessment of Global Ocean Biogeochemistry Models for Ocean Carbon Sink Estimates in RECCAP2 and Recommendations for Future Studies |
| title_fullStr | Assessment of Global Ocean Biogeochemistry Models for Ocean Carbon Sink Estimates in RECCAP2 and Recommendations for Future Studies |
| title_full_unstemmed | Assessment of Global Ocean Biogeochemistry Models for Ocean Carbon Sink Estimates in RECCAP2 and Recommendations for Future Studies |
| title_short | Assessment of Global Ocean Biogeochemistry Models for Ocean Carbon Sink Estimates in RECCAP2 and Recommendations for Future Studies |
| title_sort | assessment of global ocean biogeochemistry models for ocean carbon sink estimates in reccap2 and recommendations for future studies |
| topic | ocean biogeochemical modeling ocean carbon sink carbon cycle |
| url | https://doi.org/10.1029/2023MS003840 |
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