Dynamics of the Hadley circulation in an axisymmetric model undergoing stratification periodic forcing

Tartaglione, Nazario

doi:https://doi.org/10.5194/npg-24-167-2017

Articles | Volume 24, issue 2

https://doi.org/10.5194/npg-24-167-2017

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

https://doi.org/10.5194/npg-24-167-2017

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

Articles | Volume 24, issue 2

Research article

|

20 Apr 2017

Research article |

| 20 Apr 2017

Dynamics of the Hadley circulation in an axisymmetric model undergoing stratification periodic forcing

Nazario Tartaglione

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Final revised paper (published on 20 Apr 2017)
Preprint (discussion started on 08 Nov 2016)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'discussin comments', Anonymous Referee #1, 20 Dec 2016
- AC1: 'Reply', Nazario Tartaglione, 20 Dec 2016
RC2: 'interacrive discussion', Anonymous Referee #1, 20 Dec 2016
RC3: 'Referee review', Anonymous Referee #2, 22 Dec 2016
AC2: 'Author response', Nazario Tartaglione, 24 Jan 2017

Peer-review completion

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

AR by Nazario Tartaglione on behalf of the Authors (24 Jan 2017) Author's response Manuscript

ED: Reconsider after major revisions (further review by Editor and Referees) (27 Jan 2017) by Victor Shrira

ED: Reconsider after major revisions (further review by Editor and Referees) (30 Jan 2017) by Victor Shrira

ED: Referee Nomination & Report Request started (31 Jan 2017) by Victor Shrira

RR by Anonymous Referee #1 (14 Feb 2017)

RR by Anonymous Referee #2 (16 Feb 2017)

Suggestions for revision or reasons for rejection

The author has evidently taken fairly full account of my earlier comments in producing a revised version of his manuscript. This has addressed a number of my earlier concerns and, together with a revision of the English, the manuscript has been significantly improved to the point where the paper is almost acceptable as it stands.

Under point 1), I would agree that the phase portraits suggest a singly periodic behavior is dominant, although the small amplitude departures from a single limit-cycle trajectory do appear to show some short timescale periodicity which might be dynamically significant - though this component does not seem to show up in the spectra in Fig. 2. For the 23 day forcing period case the oscillations look to have a period near roughly a 1 day(?) period? But this is probably not a major issue and I am happy to leave this for the author to answer at his discretion.

Under point 2), the additional tests carried out are useful in establishing the robustness of the bifurcation that is reported.

For point 3), I was simply concerned that the model imposed a symmetry in the circulation about the equator which would only really apply either at equinoxes or for a planet whose obliquity was zero. So one could ask whether the same bifurcation would occur if this symmetry were broken e.g. to represent the circulation close to a solstice? Also, how significant is it that the forcing pushes the stratification precisely towards neutral stability at its extreme? What would happen if the minimum stability being forced was either weakly stable or even weakly unstable? These points are again concerned with establishing how robust the behavior might be and therefore how applicable generally the results might be to the real Earth (or other planet).

But in other respects I am content to recommend acceptance of this manuscript for publication.

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ED: Publish subject to minor revisions (further review by Editor) (26 Feb 2017) by Victor Shrira

AR by Nazario Tartaglione on behalf of the Authors (08 Mar 2017) Author's response Manuscript

ED: Publish as is (09 Mar 2017) by Victor Shrira

AR by Nazario Tartaglione on behalf of the Authors (17 Mar 2017) Manuscript

Short summary

This paper aims to show how the tropical circulation responds to changes of the vertical stratification of the imposed temperature that drives the model. These changes mimic the presence of water vapor cycles. Thus, for simplicity's sake we impose a periodic change of this stratification with variable periods of 10–90 days. The model responds with quasi-periodic oscillations having two or more dominant frequencies. After a long forcing time period, chaotic behavior starts to appear cyclically.