Lidar temperature series in the middle atmosphere as a reference data set – Part 2: Assessment of temperature observations from MLS/Aura and SABER/TIMED satellites

Wing, Robin; Hauchecorne, Alain; Keckhut, Philippe; Godin-Beekmann, Sophie; Khaykin, Sergey; McCullough, Emily M.

doi:https://doi.org/10.5194/amt-11-6703-2018

Articles | Volume 11, issue 12

https://doi.org/10.5194/amt-11-6703-2018

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

https://doi.org/10.5194/amt-11-6703-2018

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

Articles | Volume 11, issue 12

Research article

|

18 Dec 2018

Research article |

| 18 Dec 2018

Lidar temperature series in the middle atmosphere as a reference data set – Part 2: Assessment of temperature observations from MLS/Aura and SABER/TIMED satellites

Robin Wing, Alain Hauchecorne, Philippe Keckhut, Sophie Godin-Beekmann, Sergey Khaykin, and Emily M. McCullough

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Final revised paper (published on 18 Dec 2018)
Preprint (discussion started on 02 May 2018)

Interactive discussion

Status: closed

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

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RC1: 'Please also use the additional 6 years of data since 2011', Anonymous Referee #1, 23 May 2018
- AC1: 'Response to Referee 1', Robin Wing, 27 Sep 2018
RC2: 'Suitable for publication after major revisions', Anonymous Referee #2, 14 Jul 2018
- AC2: 'Response to Referee 2', Robin Wing, 27 Sep 2018

Peer-review completion

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

AR by Robin Wing on behalf of the Authors (27 Sep 2018) Author's response Manuscript

ED: Referee Nomination & Report Request started (05 Oct 2018) by Markus Rapp

RR by Anonymous Referee #1 (21 Oct 2018)

Suggestions for revision or reasons for rejection

The paper reports on the long term comparison of stratospheric and mesospheric temperature profiles measured by lidar at Haute Provence Observatory with nearby temperature profiles retrieved by the SABER and MLS satellite instruments. The authors find systematic altitude and season dependent differences of the order of a few Kelvin, which can be reduced by 2 to 4 K, when obvious altitude shifts in the satellite temperature profiles are corrected for. After correction, systematic lidar - SABER temperature differences are reduced to less than +-2 K, systematic lidar - MLS temperature differences to about 4.5 K with a +-1 K vertical oscillation. I think this is an important and very comprehensive long-term comparison of key data sets for the analysis of stratospheric and mesospheric temperature variations and trends.

In this revised version the authors have addressed nearly all comments from the reviewers in a satisfactory way. In particular, they have extended the underlying time series by 6 years, whithout major changes in the results.

There are a few larger issues, that I think should still be addressed. The line numbers in my comments below refer to the change-tracked version of the revised manuscript.

At the end of the paper (Fig.~14, Section 7 end, or Section 8), I am missing more comparison of the current results with the results from previous studies, which are discussed at length in Section 1.2. So I am wondering how the new results fit into scientific context, especially for altitudes lower than the 70 km discussed around line 387. Ideally there would be another Figure like Fig. 14, which shows comparable difference profiles from previous studies. At the least there should be more discussion than in the current text. Right now, the reader is left wondering where the remaining differences between 30 and 70 km might come from, and how consistent they are with other studies.

I am also missing a (brief) discussion of the satellite averaging kernels (which seem to wider for MLS than for SABER), and how they might affect results. e.g. by reducing temperature peaks and valleys, compared to the (presumably) higher vertical resolution lidar profiles. I think the authors need to add some thoughts about that, and add some corresponding material.

Minor issues:
Overall, I find the manuscript lengthy and wordy. I think a thorough read-through with editing for more conciseness and removal of repetitions would be very beneficial.

Minor suggestions:

line 15: replace "the vertical artifacts" by "apparent vertical oscillations"

lines 46 to 77: I think the 2nd and 3rd point are really the same. Lidars measure range and altitude very precisely, unlike the satellite retrieval. I think this could be shortened substantially.

line 394: incorrect altitude is certainly not the only thing that can go wrong. So maybe replace "incorrect altitudes in" by "biases or errors of"?

lines 396/7: Replace "seasonal variability" by "seasonally varying bias"? It seems to me that the latter is really meant here.

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ED: Publish subject to minor revisions (review by editor) (21 Nov 2018) by Markus Rapp

AR by Robin Wing on behalf of the Authors (29 Nov 2018) Author's response Manuscript

ED: Publish as is (30 Nov 2018) by Markus Rapp

AR by Robin Wing on behalf of the Authors (06 Dec 2018)

Short summary

We have compared 2433 nights of OHP lidar temperatures (2002–2018) to temperatures derived from the satellites SABER and MLS. We have found a winter stratopause cold bias in the satellite measurements with respect to the lidar (−6 K for SABER and −17 K for MLS), a summer mesospheric warm bias for SABER (6 K near 60 km), and a vertically structured bias for MLS (−4 to 4 K). We have corrected the satellite data based on the lidar-determined stratopause height and found a significant improvement.