Sensitivity of the tropical stratospheric ozone response to the solar rotational cycle in observations and chemistry–climate model simulations

Thiéblemont, Rémi; Marchand, Marion; Bekki, Slimane; Bossay, Sébastien; Lefèvre, Franck; Meftah, Mustapha; Hauchecorne, Alain

doi:https://doi.org/10.5194/acp-17-9897-2017

Articles | Volume 17, issue 16

https://doi.org/10.5194/acp-17-9897-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/acp-17-9897-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 17, issue 16

Research article

|

23 Aug 2017

Research article |

| 23 Aug 2017

Sensitivity of the tropical stratospheric ozone response to the solar rotational cycle in observations and chemistry–climate model simulations

Rémi Thiéblemont, Marion Marchand, Slimane Bekki, Sébastien Bossay, Franck Lefèvre, Mustapha Meftah, and Alain Hauchecorne

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Final revised paper (published on 23 Aug 2017)
Preprint (discussion started on 24 Jan 2017)

Interactive discussion

Status: closed

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

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RC1: 'referee report', Anonymous Referee #2, 18 Feb 2017
- AC1: 'Reply to reviewer #2', Rémi Thiéblemont, 10 May 2017
RC2: 'review', Anonymous Referee #3, 18 Feb 2017
- AC2: 'Reply to reviewer #3', Rémi Thiéblemont, 10 May 2017
RC3: 'Review', Anonymous Referee #1, 20 Feb 2017
- AC3: 'Reply to reviewer #1', Rémi Thiéblemont, 10 May 2017

Peer-review completion

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

AR by Rémi Thiéblemont on behalf of the Authors (10 May 2017) Author's response Manuscript

ED: Referee Nomination & Report Request started (23 May 2017) by Gabriele Stiller

RR by Anonymous Referee #2 (02 Jun 2017)

RR by Anonymous Referee #3 (05 Jun 2017)

Suggestions for revision or reasons for rejection

The authors have extensively revised the paper in response to my comments and those from the other reviewers. The paper is acceptable after minor revisions.

The results seem to be reliable and well-explained within the context of the simulations performed and therefore are publishable. However, I am still concerned that the authors have chosen to go ahead with their analysis even though they acknowledge the shortcoming of the model due to the neglect of daily solar flux variability in the heating calculation. This is laid out quite in the open so the reader is not being misled in any way. There will no doubt be some readers who mistrust the results since they are derived from simulations using a model that is not exactly appropriate for this particular investigation. As far as I can tell, the reason for omitting this key physical process is not that it is difficult to include because of technical issues or a poor understanding of the physics but rather because they prefer not to rerun the model with the correction. Developing model routines and running for long simulations take a lot of time, effort, and computing resources. That effort and expense can be worthwhile if and when it gives confidence that the results represent the current understanding of the atmosphere.

Minor comments:

(p. 2; l. 23) You could also add Envisat GOMOS and TIMED SABER to your list.

(p. 4, l. 12-15) Check the logic of these two sentences; Gruzdev (misspelled in the manuscript) et al -> enhanced solar gives reduced O3 sensitivity but then Kubin et al -> weak solar gives enhanced O3 sensitivity. That’s the same, right?

(p. 12, l. 3) It would be more accurate to say that the temperature response is controlled by the ozone concentration, rather than the ozone production. The solar flux affects both production and loss of ozone.

(p. 12, l. 9-10) (“More sensitivity experiments”) Related to the general comment above, it would be a better use of your time to incorporate a heating routine that includes the option of daily varying spectrally resolved solar flux. More sensitivity experiments are not recommended; now is a good time to move on to an updated algorithm.

(p. 12, l. 29) “errors” This is not the right word since you are showing variations that include other physical processes such as dynamics and do not include systematic errors.

(p. 15, discussion of Figure 9) I still have trouble seeing the inverse relationships that are used to motivate the later analysis (9b vs. 9d; 9b vs. 9c). Could you add an extra panel to Figure 9 that would overlay these so that the inverse relationships are more apparent?

Editorial comments:

(p. 8, l. 29) What is the subject of “cover”?

(p. 9, l. 26) What does “presumably because” refer to?

(p. 11; l. 11-13) This sentence has no verb.

(p. 11, l. 28) “difference” from what?

(caption to Figure 7) The last sentence is repeated.

(p. 15, l. 32) “shown in the insert of Fig. 9a” -> “shown in Fig. 9a”

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RR by Anonymous Referee #1 (07 Jun 2017)

Suggestions for revision or reasons for rejection

Answering my first major comment the authors state that neglecting the direct heating rate response to solar irradiance variability does not play substantial role. In support of this statement they use the results published by Sukhodolov et al. (2017) and Swartz et al. (2012). I do not find these arguments convincing. Swartz et al. (2012. Figure 2) show the results averaged over 60 deg. South to 60 deg. North. It is known that the temperature response to solar irradiance variability maximizes in the tropical area and therefore these results do not confirm the author’s hypothesis about the small influence of the pure radiative heating. I guess, for the tropical area (which is considered in the manuscript) the contribution of the direct radiative heating response should be 2-3 times higher than 10% obtained by Swartz et al. (2012). It is partially confirmed by Sukhodolov et al. (2016, fig. 4, doi:10.1002/ 2015JD024277) which shows about 28% reduction of the ozone response by direct heating rate responses. I do not think that 28% can be qualified as small and negligible effect. The comparison with the results of Sukhodolov et al., (2017) is also not convincing, because we cannot expect identical results from two models using completely different chemical and photolysis modules. It was shown by Sukhodolov et al. (2016, Figure 7) that the photolysis rates calculated with SOCOL and LMDZ-Reprobus can differ quit substantially. It could well be that the same ozone response in two models is the result of higher pure photochemical response in SOCOL compensated by the inclusion of direct heating rate response. If it is the case the reported in the manuscript O3 response is overestimated by about 30%. I think, the authors should agree on this and describe it properly in the text. It will be better than the use of wrong arguments to defend the applied experimental set-up.

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ED: Reconsider after minor revisions (Editor review) (19 Jun 2017) by Gabriele Stiller

AR by Rémi Thiéblemont on behalf of the Authors (07 Jul 2017) Author's response Manuscript

ED: Publish as is (24 Jul 2017) by Gabriele Stiller

AR by Rémi Thiéblemont on behalf of the Authors (24 Jul 2017)