Seasonal variability of the oxygen minimum zone off Peru in a
high-resolution regional coupled model

Vergara, Oscar; Dewitte, Boris; Montes, Ivonne; Garçon, Veronique; Ramos, Marcel; Paulmier, Aurélien; Pizarro, Oscar

doi:https://doi.org/10.5194/bg-13-4389-2016

Articles | Volume 13, issue 15

https://doi.org/10.5194/bg-13-4389-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/bg-13-4389-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 13, issue 15

Research article

|

08 Aug 2016

Research article |

| 08 Aug 2016

Seasonal variability of the oxygen minimum zone off Peru in a high-resolution regional coupled model

Oscar Vergara, Boris Dewitte, Ivonne Montes, Veronique Garçon, Marcel Ramos, Aurélien Paulmier, and Oscar Pizarro

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Final revised paper (published on 08 Aug 2016)
Preprint (discussion started on 18 Jan 2016)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'Review', Anonymous Referee #1, 17 Feb 2016
- AC1: 'Authors responses to comments on MS bg-2015-631', Oscar Vergara, 03 May 2016
RC2: 'Review of Vergara et al. 2016', Anonymous Referee #2, 08 Mar 2016
- AC2: 'Authors responses to comments on MS bg-2015-631', Oscar Vergara, 03 May 2016

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (05 May 2016) by Katja Fennel

AR by Oscar Vergara on behalf of the Authors (06 May 2016) Author's response Manuscript

ED: Referee Nomination & Report Request started (10 May 2016) by Katja Fennel

RR by Anonymous Referee #2 (09 Jun 2016)

Suggestions for revision or reasons for rejection

Page 10, Line 5-6: “the modeled oxygen content is however underestimated as compared to CARS in certain regions of the domain, “ This should be rephrased to clearly state the model is biased high in certain regions and underestimates the volume of suboxic water. This may be due to the vigorous mixing occurring in the EKE figure the authors included with their comments. Pointing to a reason for the bias would provide ways to shape the conclusions presented here.
Page 10, Line 13-14: The observations are not the only thing at fault. No model is perfect and so the biases here should be openly discussed. Please make sure to discuss the results with an even hand.
Page 22, Lines 8-10. Bianucci et al is not the only oxygen model in the N-CCS which investigated the role of sediments. Siedlecki et al (2015) found them to play a significant role on the Washington shelf, and they have been found to be important in other regions as well.

Page 22, Lines 8-10. While I applaud the authors for trying to present the limitations of the model results prior to the discussion of implications, it seems prudent here to discuss the results from the figure included in your comments to reviewers (figure A2 or Figure 1 in the paper). Specifically, the simulation seems quite a lot higher in EKE south of 20 S. so the “ventilation” and EKE contributions in this region of the budget should be viewed within the context of this bias. The entire discussion of the Southern Boundary and the mechanisms surrounding that region need to be backed off and put in the context of the mixing and probably ventilation in the region being biased high.

That said, a lot of other results in the paper are worthy of highlighting, but the boundary stories seems like the wrong one to focus on in areas of the discussion and conclusions. Altering the presentation of this result in the paper should take minor revisions.

Siedlecki, S.A., Banas, N., Davis, K.A., Giddings, S., Hickey, B.M., MacCready, P., Connolly, T., and S. Geier, Seasonal and interannual oxygen variability on the Washington and Oregon continental shelves, (2015), J. Geophys. Res. Oceans, 120, DOI: 10.1002/2014JC010254

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ED: Publish subject to minor revisions (Editor review) (10 Jun 2016) by Katja Fennel

AR by Oscar Vergara on behalf of the Authors (16 Jun 2016) Author's response Manuscript

ED: Publish as is (17 Jun 2016) by Katja Fennel

AR by Oscar Vergara on behalf of the Authors (23 Jun 2016)

Short summary

The Southeast Pacific hosts one of the most extensive oxygen minimum zone (OMZ), yet the dynamics behind it remain unveiled. We use a high-resolution coupled physical–biogeochemical model to document the seasonal cycle of dissolved oxygen within the OMZ in both the coastal zone and the offshore ocean. The OMZ seasonal variability is driven by the seasonal fluctuations of the dissolved oxygen eddy flux, with a peak in Austral winter (fall) at the northern (southern) boundary and near the coast.