Local time dependence of polar mesospheric clouds: a model study

Schmidt, Francie; Baumgarten, Gerd; Berger, Uwe; Fiedler, Jens; Lübken, Franz-Josef

doi:https://doi.org/10.5194/acp-18-8893-2018

Articles | Volume 18, issue 12

https://doi.org/10.5194/acp-18-8893-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

Sources, propagation, dissipation and impact of gravity waves...

https://doi.org/10.5194/acp-18-8893-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 18, issue 12

Research article

|

26 Jun 2018

Research article |

| 26 Jun 2018

Local time dependence of polar mesospheric clouds: a model study

Francie Schmidt, Gerd Baumgarten, Uwe Berger, Jens Fiedler, and Franz-Josef Lübken

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Final revised paper (published on 26 Jun 2018)
Preprint (discussion started on 11 Oct 2017)

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, 03 Nov 2017
- AC1: 'Response to reviewer comments', Gerd Baumgarten, 13 Apr 2018
RC2: 'Reviewer Comment', Anonymous Referee #2, 12 Nov 2017
- AC2: 'Response to reviewer comments', Gerd Baumgarten, 13 Apr 2018

Peer-review completion

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

AR by Gerd Baumgarten on behalf of the Authors (13 Apr 2018) Author's response Manuscript

ED: Referee Nomination & Report Request started (03 May 2018) by Jörg Gumbel

RR by Anonymous Referee #2 (18 May 2018)

Suggestions for revision or reasons for rejection

The reviewer thanks the authors for their careful and thorough responses to the reviewer’s comments. The manuscript is much clearer and much improved over the original version and the authors draw some useful conclusions that the community can build upon.

The reviewer has some small remaining issues and would recommend publication following adequate responses to these, which are summarized below.

1. Abstract, lines 12 and 13. In order to avoid any ambiguity, instead of reporting “variations of temperature at 69 N are in the range of 6 K” it is more clear and concise to state “variations of temperature at 69 N are +/-3 K”. That way there is no confusion about the amplitude of the variations. Similarly, “the water vapor variation is about 7 ppmv” should instead be “the water vapor variation is about +/-3.5 ppmv”. This also applies to the conclusions on p. 21, lines 10 and 11. Please also use this more explicit text for the paragraph on p. 6 lines 4-14 and anywhere else in the manuscript were there could be ambiguity. Thank you.

2. P. 5, line 21 to p. 6 line 3. These three sentences are a rather significant dismissal of the cited work. Note that Stevens et al. (2017) use a relatively new version of the SOFIE temperatures that removed a warm bias at the mesopause present in earlier versions. In addition, the reviewer sees very little difference between the ~140 K SOFIE temperature reported at 90 km and temperatures reported at 90 km by Singer et al. (2003, their Figures 2 and 3 for 69 N). Furthermore, although the July 2003 data appear to be have lower temperatures in Singer et al. (2005, their Figure 2), the July 2002 data appear to less than 10 K different than reported July 2009 data from SOFIE. If the authors know of a specific reference that indicates the July 2009 SOFIE data reported by Stevens et al. (2017) is biased ~10 K high at 90 km, please provide it. Otherwise please revise the text here to more accurately reflect the published record. Thank you.

3. Figure 5. It appears that IWC values of zero (or less than the indicated threshold) are not included in this figure. If that is correct, then please say so in the caption to avoid any confusion. The authors are now clearer about this elsewhere in the text. Also, please choose different symbols to more clearly distinguish the ascending and descending node data for CIPS in Figure 5. Finally, please indicate the version of CIPS data used, as they have done for the SOFIE data. Thank you.

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ED: Publish subject to minor revisions (review by editor) (26 May 2018) by Jörg Gumbel

AR by Gerd Baumgarten on behalf of the Authors (30 May 2018) Author's response Manuscript

ED: Publish as is (14 Jun 2018) by Jörg Gumbel

AR by Gerd Baumgarten on behalf of the Authors (17 Jun 2018)

Short summary

Local time variations of polar mesospheric clouds (PMCs) in the Northern Hemisphere are studied using a combination of a global circulation model and a microphysical model. We investigate the brightness, altitude, and occurrence of the clouds and find a good agreement between model and observations. The variations are caused by tidal structures in background parameters. The temperature varies by about 2 K and water vapor by about 3 ppmv at the altitude of ice particle sublimation near 81.5 km.