Articles | Volume 22, issue 18
https://doi.org/10.5194/bg-22-5009-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.Northern North Atlantic climate variability controls on ocean carbon sinks in EC-Earth3-CC
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- Final revised paper (published on 26 Sep 2025)
- Preprint (discussion started on 26 Mar 2025)
Interactive discussion
Status: closed
Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor
| : Report abuse
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RC1: 'Comment on egusphere-2025-1218', Anonymous Referee #1, 25 Apr 2025
- AC1: 'Reply on RC1', Anna Pedersen, 23 May 2025
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RC2: 'Comment on egusphere-2025-1218', Anonymous Referee #2, 25 Apr 2025
- AC2: 'Reply on RC2', Anna Pedersen, 23 May 2025
Peer review completion
AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
ED: Reconsider after major revisions (26 May 2025) by Peter Landschützer

AR by Anna Pedersen on behalf of the Authors (23 Jun 2025)
Author's response
Author's tracked changes
Manuscript
ED: Referee Nomination & Report Request started (24 Jun 2025) by Peter Landschützer
RR by Anonymous Referee #1 (30 Jun 2025)
ED: Publish as is (10 Jul 2025) by Peter Landschützer

AR by Anna Pedersen on behalf of the Authors (12 Jul 2025)
The aim of the study is to understand the sensitivity and drivers of the atmosphere-ocean flux in an ESM system on different time scales The paper explores indices calculated from physical parameters and dynamical process in different Northern North Atlantic regions from the EC-Earth3-CC model to find controlling factors of atmosphere-ocean CO2 flux variability. This is done in terms of simple linear multivariable regression models across interannual and decadal time scales. The analyses finds that the chosen indices play a central role, but that they exert regionally and temporally varying influence in the areas of interest.
The main conclusion is that the CO2 flux variability cannot be attributed to simple linear relationships with individual predictors but instead emerges from complex interactions among multiple processes.
The novelty of the current work is the establishment of which predictors that can explain the CO2 fluxvariability in five regions in the North Atantic that are subject to quite different dynamic processes and atmospheric forcings.
The concept of the work is interesting and useful, especially because it allows connecting basic variables and processes that can be obtained from different ocean climate and biogeochemical models commonly used to study climate change.
Major comments:
L590-591: Here you say that the results of your regression model analysis allow you to consider whether you can predict CO2 flux variability in future scenarios. What do you mean by this?
L591-592: You also mention that these regression models applied on scenario runs from EC-Earth3-CC or other ESMs can be beneficial for the understanding of the future climate system.
I agree that using the regression models on future scenarios from EC-Earth3-CC can contribute to an increased understanding, but I would be careful by applying the same regression models on other ESMs as other ESMs may have 1) more realistic or less realistic indices (predictors) than EC-Earth3-CC (e.g. sea ice index), and 2) the relationship between them may be significanty different so that the regression models from EC-Earth3-CC may not hold in other models. The risk for this may be particularly high in future scenarios when models tend to deviate from each other in terms of circulation and trends. I therefore think that the method developed in this study is useful, but that the regression models should be developed separately for each model.
Minor comments:
L556-557: My impression here is that wind speed and MLD are considered as two independent predictors, but the MLD is also a function of wind, in addition to temperature and salinity.
L560-561: Is there a contradiction between NSE being the smallest region and exhibiting the highest variability and mean flux?
L569-586: I think this discussion of the counter-intuitive negative correlations is particularly interesting and underline the complex interplay between the different indices.
L67: What is meant by “deep decadal variability”?
L96: Also Orvik et al., 2022 could be added after Lozier et al., 2019.
L97: The last sentence in the paragraph is not very well connected to the ones before that.
L114: Change “maos” to “maps”.
L170: Remove “a” before “positive”.
L210: Remove “is”.
L305: Change “oir” to “our”.
L377: Hatun et al., 2005 should also be added.
L400: Change “stregthening” to “streingthening”.
Table 3: I guess only significant correlations are shown.
L477: Please add a “,” after “In the following”.
L552: Change “table” to “Table”.
L661: Change “amog” to “among”.