Deriving stratospheric age of air spectra using an idealized set of chemically active trace gases

Hauck, Marius; Fritsch, Frauke; Garny, Hella; Engel, Andreas

doi:https://doi.org/10.5194/acp-19-5269-2019

Articles | Volume 19, issue 7

https://doi.org/10.5194/acp-19-5269-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-19-5269-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 19, issue 7

Research article

|

17 Apr 2019

Research article |

| 17 Apr 2019

Deriving stratospheric age of air spectra using an idealized set of chemically active trace gases

Marius Hauck, Frauke Fritsch, Hella Garny, and Andreas Engel

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Final revised paper (published on 17 Apr 2019)
Preprint (discussion started on 09 Oct 2018)

Interactive discussion

Status: closed

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

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RC1: 'reviewer comment', Anonymous Referee #1, 06 Nov 2018
RC2: 'Review of Hauck et al.', Anonymous Referee #3, 07 Nov 2018
RC3: 'Review on: "Deriving stratospheric age of air spectra using chemically active trace gases" by Hauck et al.', Anonymous Referee #2, 20 Nov 2018
AC1: 'Reply to referees', Marius Hauck, 15 Jan 2019

Peer-review completion

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

AR by Marius Hauck on behalf of the Authors (15 Jan 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (24 Jan 2019) by Rolf Müller

RR by Anonymous Referee #3 (05 Feb 2019)

RR by Anonymous Referee #1 (10 Feb 2019)

Suggestions for revision or reasons for rejection

I appreciate the additional discussion and calculations the authors have added to the manuscript on the potential applicability of the method, which has improved the manuscript. However, I am still not convinced of the value of the manuscript. I am totally supportive of model-based studies that use model output for proof of concept studies, and it is not necessary for method to be applied to data. However, I think there has to be some chance that the concept (or slight modification of it) can be applied to data (or data that could be collected). I see no evidence of this.

The challenge for current approach is the reliance of tracers that are radioactive (constant loss) with a wide range of lifetimes. What possible tracers are the authors thinking about? The sensitivity calculations with less than 40 tracers is useful for the issue of limited number of tracers, but still not anywhere near realistic. What are the possible tracers with a 1 month or even 25 month stratospheric lifetime?

Perhaps more importantly is the fact that trace gases that are measured are chemically active and not radioative (so title of paper is misleading), and their loss varies spatially and with time. This makes the problem a lot more complicated (and seasonality is a second order issue compared to this). The method might be extended to include time varying loss rates but I am not convinced. This is the issue that needs to tested in a proof of concept paper, i.e. can the Schoeberl et al method be extended.

The manuscript is technically fine and now includes some discussion of application, so it would be OK if it was published. I am just not sure what impact it will have on advancing our understanding or others in the community.

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RR by Anonymous Referee #2 (19 Feb 2019)

ED: Publish subject to minor revisions (review by editor) (06 Mar 2019) by Rolf Müller

AR by Marius Hauck on behalf of the Authors (08 Mar 2019) Author's response Manuscript

ED: Publish subject to technical corrections (18 Mar 2019) by Rolf Müller

AR by Marius Hauck on behalf of the Authors (18 Mar 2019) Author's response Manuscript

Short summary

The paper presents a modified method to invert mixing ratios of chemically active tracers into stratospheric age spectra. It features an imposed seasonal cycle to include transport seasonality into the spectra. An idealized set of tracers from a model is used as proof of concept and results are in good agreement with the model reference, except for the lowermost stratosphere. Applicability is studied with focus on number of tracers and error tolerance, providing a starting point for future work.