Tropopause-level planetary wave source and its role  in two-way troposphere–stratosphere coupling

Boljka, Lina; Birner, Thomas

doi:https://doi.org/10.5194/wcd-1-555-2020

Articles | Volume 1, issue 2

https://doi.org/10.5194/wcd-1-555-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/wcd-1-555-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 1, issue 2

Research article

|

17 Oct 2020

Research article |

| 17 Oct 2020

Tropopause-level planetary wave source and its role in two-way troposphere–stratosphere coupling

Lina Boljka and Thomas Birner

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Final revised paper (published on 17 Oct 2020)
Supplement to the final revised paper
Preprint (discussion started on 26 May 2020)

Interactive discussion

Status: closed

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

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RC1: 'review of Boljka and Birner', Anonymous Referee #1, 21 Jun 2020
- AC1: 'Response to Reviewer 1', Lina Boljka, 05 Aug 2020
RC2: 'review Boljka and Birner', Anonymous Referee #2, 24 Jun 2020
- AC2: 'Response to Reviewer 2', Lina Boljka, 05 Aug 2020

Peer-review completion

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

AR by Lina Boljka on behalf of the Authors (16 Aug 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (20 Aug 2020) by Pedram Hassanzadeh

RR by Anonymous Referee #1 (08 Sep 2020)

For final publication, the manuscript should be

accepted as is

accepted subject to technical corrections

accepted subject to minor revisions

reconsidered after major revisions

I would be willing to review the revised paper, if the editor considers it necessary.

I am not willing to review the revised paper.

rejected

Suggestions for revision or reasons for rejection

Second review of " Tropopause-level planetary wave source and its role in two-way" by Boljka and Birner

The authors have satisfactorily addressed my major comments. Here are some final minor changes before publication:
1. Line 33 and 35: the authors imply that a 1.95std deviation anomaly of tropospheric wave flux is not “strong”, and a SSD or SSW preceded by such an anomalous tropospheric wave flux event is not associated with a tropospheric precursor. I would beg to differ to both of these implications. To be constructive, the simplest way to revise this is to replace “strong” with “extreme” on lines 33 and 35.

2. Line 71: this sentence reads a bit funny, suggest rewriting

3. Line 76-77 I had trouble following the logic of this sentence. That being said, I accept the authors rebuttal to my original criticism regarding using QG theory and turbulence, and the revised section 2 is much better than before.

4. The paragraph from line 128 to line 148 is rather long, and would benefit from being split in two or even three (e.g. at line 142)

5. Line 303 by *an* equally strong

6. line 385 prior to *the* wave source event

7. Is the difference in the tropospheric impact between tropopause wave source SSWs and surface wave source SSWs statistically significant? Maybe add a difference plot? The difference plot should be created for both quasi-reanalysis and the model, and it is conceivable that the limited sample size leads to a lack of significance. If the difference indeed isn’t significant, then the discussion in section 5 (as well as the conclusions section and abstract) should be modified accordingly.

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RR by Anonymous Referee #2 (24 Sep 2020)

For final publication, the manuscript should be

accepted as is

accepted subject to technical corrections

accepted subject to minor revisions

reconsidered after major revisions

I would be willing to review the revised paper, if the editor considers it necessary.

I am not willing to review the revised paper.

rejected

Suggestions for revision or reasons for rejection

I find the manuscript improved with just a few minor issues remaining. They are:

L134-139: Turbulence theory: I realise this text has been changed in response to other referee comments, but I believe there is still a certain lack of accuracy in the statement as written now. Triad interactions in 2D turbulence are explicitly defined as the interactions of three waves with wavenumbers k1 = k2+k3. So they are wave- wave interactions of a finite number of distinct waves (three of them). And if k1,k2,k3 are small numbers, they are wave-wave interactions of a finite number of distinct large waves. So the statement in the manuscript saying the authors concentrate on these interactions “rather than [...] 2-D turbulence)” is not accurate. Please clarify.

L 216: “SSWs are defined as a subset of the identified SSDs”. How do these SSWs compare to the classical Charlton & Polvani (2007) SSWs? Are all SSDs which also reverse zonal flow CP07 SSWs? What about the other way round? It would be good to have a statement here to get a feeling of how similar the here discussed SSWs are to the CP07 SSWs.

L 224-225: This change after my previous comments is not satisfying, as it still suggests there are no models were k=1 forcing does produce SSWs. So, why not make this statement much simpler (and more accurate), by saying “.., however our model does not exhibit SSWs when forced with k=1 forcing (Table 1 in Sheshadri et al., 2015).”

L229-270: I got very confused about 10-day running means here. You say you first smooth the data with a 10-day running mean (L 229), then you apply a 10-day smoothing before compositing (L 251), and then you smooth the data with a 10-day running mean before plotting (L 270). How many times, exactly, do you apply a 10- day running mean until you get to the final, plotted results? If it’s more than once, why is this necessary?

L522, 523: Instead of just referring to Fig 6b,e and 7b,e, it would be much clearer if you could discuss the physical quantity and add the figure information to the discussion, maybe in parentheses.

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ED: Publish subject to minor revisions (review by editor) (24 Sep 2020) by Pedram Hassanzadeh

AR by Lina Boljka on behalf of the Authors (07 Oct 2020) Author's response Manuscript

ED: Publish as is (09 Oct 2020) by Pedram Hassanzadeh

AR by Lina Boljka on behalf of the Authors (09 Oct 2020)

Short summary

This study addresses the origin and impacts of a source of large-scale atmospheric waves in the lower stratosphere, which have not been examined before. This wave source is caused by interactions of waves of smaller scales. Here we show that as it lies in the lower stratosphere, this wave source can precede extreme events in the stratosphere and that such events can then lead to a response of the tropospheric weather patterns several weeks later (potential for long-term forecasting).