TY - JOUR
T1 - A framework to evaluate and elucidate the driving mechanisms of coastal sea surface pCO2 seasonality using an ocean general circulation model (MOM6-COBALT)
AU - Roobaert, Alizée
AU - Resplandy, Laure
AU - Laruelle, Goulven G.
AU - Liao, Enhui
AU - Regnier, Pierre
N1 - Funding Information:
Financial support. This research received financial support from BELSPO through the project ReCAP, which is part of the Belgian research program FedTwin, and from the European Union’s Horizon 2020 research and innovation program VERIFY (grant no. 776810) and ESM 2025 – Earth System Models for the Future (grant no. 101003536) projects. Laure Resplandy and Enhui Liao acknowledge the Cooperative Institute for Modeling the Earth System between NOAA GFDL and Princeton University, the Sloan Research foundation, and the Princeton Catalysis Initiative.
Funding Information:
This research received financial support from BELSPO through the project ReCAP, which is part of the Belgian research program FedTwin, and from the European Union's Horizon 2020 research and innovation program VERIFY (grant no. 776810) and ESM 2025 – Earth System Models for the Future (grant no. 101003536) projects. Laure Resplandy and Enhui Liao acknowledge the Cooperative Institute for Modeling the Earth System between NOAA GFDL and Princeton University, the Sloan Research foundation, and the Princeton Catalysis Initiative. We thank the two anonymous reviewers and the Ocean Science editor Mario Hoppema for their constructive comments. We thank the MOM6 ocean model development team and are grateful to David Luet and the Princeton Institute for Computational Science and Engineering (PICSciE) for their help and technical support for running the ocean model MOM6 at Princeton University. Goulven G. Laruelle is research associate of the F.R.SFNRS at the Université Libre de Bruxelles.
Publisher Copyright:
© 2022 Alizée Roobaert et al.
PY - 2022/1/10
Y1 - 2022/1/10
N2 - The temporal variability of the sea surface partial pressure of CO2 (pCO2) and the underlying processes driving this variability are poorly understood in the coastal ocean. In this study, we tailor an existing method that quantifies the effects of thermal changes, biological activity, ocean circulation and freshwater fluxes to examine seasonal pCO2 changes in highly variable coastal environments. We first use the Modular Ocean Model version 6 (MOM6) and biogeochemical module Carbon Ocean Biogeochemistry And Lower Trophics version 2 (COBALTv2) at a half-degree resolution to simulate coastal CO2 dynamics and evaluate them against pCO2 from the Surface Ocean CO2 Atlas database (SOCAT) and from the continuous coastal pCO2 product generated from SOCAT by a two-step neuronal network interpolation method (coastal Self-Organizing Map Feed-Forward neural Network SOM-FFN, Laruelle et al., 2017). The MOM6-COBALT model reproduces the observed spatiotemporal variability not only in pCO2 but also in sea surface temperature, salinity and nutrients in most coastal environments, except in a few specific regions such as marginal seas. Based on this evaluation, we identify coastal regions of "high"and "medium"agreement between model and coastal SOM-FFN where the drivers of coastal pCO2 seasonal changes can be examined with reasonable confidence. Second, we apply our decomposition method in three contrasted coastal regions: an eastern (US East Coast) and a western (the Californian Current) boundary current and a polar coastal region (the Norwegian Basin). Results show that differences in pCO2 seasonality in the three regions are controlled by the balance between ocean circulation and biological and thermal changes. Circulation controls the pCO2 seasonality in the Californian Current; biological activity controls pCO2 in the Norwegian Basin; and the interplay between biological processes and thermal and circulation changes is key on the US East Coast. The refined approach presented here allows the attribution of pCO2 changes with small residual biases in the coastal ocean, allowing for future work on the mechanisms controlling coastal air-sea CO2 exchanges and how they are likely to be affected by future changes in sea surface temperature, hydrodynamics and biological dynamics.
AB - The temporal variability of the sea surface partial pressure of CO2 (pCO2) and the underlying processes driving this variability are poorly understood in the coastal ocean. In this study, we tailor an existing method that quantifies the effects of thermal changes, biological activity, ocean circulation and freshwater fluxes to examine seasonal pCO2 changes in highly variable coastal environments. We first use the Modular Ocean Model version 6 (MOM6) and biogeochemical module Carbon Ocean Biogeochemistry And Lower Trophics version 2 (COBALTv2) at a half-degree resolution to simulate coastal CO2 dynamics and evaluate them against pCO2 from the Surface Ocean CO2 Atlas database (SOCAT) and from the continuous coastal pCO2 product generated from SOCAT by a two-step neuronal network interpolation method (coastal Self-Organizing Map Feed-Forward neural Network SOM-FFN, Laruelle et al., 2017). The MOM6-COBALT model reproduces the observed spatiotemporal variability not only in pCO2 but also in sea surface temperature, salinity and nutrients in most coastal environments, except in a few specific regions such as marginal seas. Based on this evaluation, we identify coastal regions of "high"and "medium"agreement between model and coastal SOM-FFN where the drivers of coastal pCO2 seasonal changes can be examined with reasonable confidence. Second, we apply our decomposition method in three contrasted coastal regions: an eastern (US East Coast) and a western (the Californian Current) boundary current and a polar coastal region (the Norwegian Basin). Results show that differences in pCO2 seasonality in the three regions are controlled by the balance between ocean circulation and biological and thermal changes. Circulation controls the pCO2 seasonality in the Californian Current; biological activity controls pCO2 in the Norwegian Basin; and the interplay between biological processes and thermal and circulation changes is key on the US East Coast. The refined approach presented here allows the attribution of pCO2 changes with small residual biases in the coastal ocean, allowing for future work on the mechanisms controlling coastal air-sea CO2 exchanges and how they are likely to be affected by future changes in sea surface temperature, hydrodynamics and biological dynamics.
UR - http://www.scopus.com/inward/record.url?scp=85123017932&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85123017932&partnerID=8YFLogxK
U2 - 10.5194/os-18-67-2022
DO - 10.5194/os-18-67-2022
M3 - Article
AN - SCOPUS:85123017932
SN - 1812-0784
VL - 18
SP - 67
EP - 88
JO - Ocean Science
JF - Ocean Science
IS - 1
ER -