The effect of instrumental stray light on Brewer and Dobson total ozone measurements

Moeini, Omid; Vaziri Zanjani, Zahra; McElroy, C. Thomas; Tarasick, David W.; Evans, Robert D.; Petropavlovskikh, Irina; Feng, Keh-Harng

doi:https://doi.org/10.5194/amt-12-327-2019

Articles | Volume 12, issue 1

https://doi.org/10.5194/amt-12-327-2019

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

https://doi.org/10.5194/amt-12-327-2019

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

Articles | Volume 12, issue 1

Research article

|

18 Jan 2019

Research article |

| 18 Jan 2019

The effect of instrumental stray light on Brewer and Dobson total ozone measurements

Omid Moeini, Zahra Vaziri Zanjani, C. Thomas McElroy, David W. Tarasick, Robert D. Evans, Irina Petropavlovskikh, and Keh-Harng Feng

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Final revised paper (published on 18 Jan 2019)
Preprint (discussion started on 01 Mar 2018)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Review of AMT-2018-2', Anonymous Referee #1, 11 May 2018
- AC2: 'Response to Anonymous referee #1', Omid Moeini, 29 Jun 2018
RC2: 'Comments to :The Effect of Instrumental Stray Light on Brewer and Dobson Total Ozone Measurements', Alberto Redondas, 19 May 2018
- AC1: 'Response to Alberto Redondas', Omid Moeini, 29 Jun 2018

Peer-review completion

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

AR by Omid Moeini on behalf of the Authors (27 Jul 2018) Author's response Manuscript

ED: Referee Nomination & Report Request started (07 Aug 2018) by Mark Weber

RR by Anonymous Referee #1 (24 Aug 2018)

Suggestions for revision or reasons for rejection

Comments on Revised Version of amt-2018-2

I would like to thank the authors for their conscientious effort to address the comments made by the referees.

For the most part I am satisfied with the responses.

In my personal opinion, however, the manuscript should not be accepted for publication while the calculations are based on what the community now regards as out-of-date ozone cross-sections. The authors have explained their decision to persist in only using Bass & Paur but unfortunately I find their reasons unconvincing. It is now established that use of Serdyuchenko cross-sections improves the agreement between Brewers and Dobsons and between AD and CD Dobson measurements.

Secondly (less importantly), I still find the discussion of ozone-layer height unsatisfactory. The authors give the issue a degree of prominence (for example, in the abstract) but the basis for their statements is left vague and the details skipped over. In the response, an "ozone climatology" is referred to but, if so, this should be made explicit. The authors have chosen to base their study on Dobson and Brewer measurements at South Pole which makes the question of effective ozone height in fact very complicated but perhaps the NOAA ozonesonde record could be made use of. The average height of the ozone layer at South Pole is claimed to be 17 km but during Antarctic Ozone Hole conditions, ozone at 17 km can be almost zero.

As a detail, the value for the radius of the Earth said to be used by the "Dobson community" at South Pole seems not be the Dobson recomended value (6371.229 km) but rather a value chosen specifically for the pole? Seeing this detail is then used in the comparisons (ie, it is contrasted with the Brewer value of the radius) it shouldn't be skipped over.

Lastly the text still states "... at high latitudes in the late winter and early spring when measurements are made at SZA and large TOC".

The subject of the study is Antarctica where this statement (large TOC in late winter and early spring) is completely untrue.

Overall, I do think the study is essentially a good one and, in principle, worthy of publication. However, I urge the authors to step back somewhat and decide what exactly the comparisons are trying to show, and then be very clear about what has been done. I appreciate the intention is to put the Dobson and Brewer data on a common footing as far as possible to concentrate on the effect of stray light, however at present I feel both that it's hard for the reader to "see the wood for the trees" but at the same time, too much focus is given to aspects which are then skipped over, such as the airmass factor adjustment.

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ED: Reconsider after major revisions (07 Sep 2018) by Mark Weber

AR by Omid Moeini on behalf of the Authors (03 Dec 2018) Author's response Manuscript

ED: Publish subject to technical corrections (20 Dec 2018) by Mark Weber

Short summary

This study documents the error caused by the effect of stray light in the Brewer and Dobson total ozone measurements using a mathematical model for each instrument. The errors caused by stray light are particularly significant at high latitudes in the late winter and early spring when measurements are made at large solar zenith angles and large total ozone column. Such errors are of considerable importance if those data are to be used for trend analysis or satellite data validation.