A new method for calculating average visibility from the relationship between extinction coefficient and visibility

Zhang, Zefeng; Guo, Hengnan; Kang, Hanqing; Wang, Jing; An, Junlin; Yu, Xingna; Lv, Jingjing; Zhu, Bin

doi:https://doi.org/10.5194/amt-15-7259-2022

Articles | Volume 15, issue 24

https://doi.org/10.5194/amt-15-7259-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/amt-15-7259-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 15, issue 24

Research article

|

19 Dec 2022

Research article |

| 19 Dec 2022

A new method for calculating average visibility from the relationship between extinction coefficient and visibility

Zefeng Zhang, Hengnan Guo, Hanqing Kang, Jing Wang, Junlin An, Xingna Yu, Jingjing Lv, and Bin Zhu

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Final revised paper (published on 19 Dec 2022)
Preprint (discussion started on 21 Mar 2022)

Interactive discussion

Status: closed

RC1:
'Comment on amt-2022-74', Anonymous Referee #1, 01 Apr 2022

General comments

The authors proved that the algorithm previously used to estimate average visibility is incorrect, and it causes the problems in previous studies related to reliability and credibility. I don’t think it is a ‘correct’ method to calculate the average of the visibility and other methods in the previous studies were incorrect. In this study, I wonder what the definition of the terms ‘correct’ and ‘incorrect’ is. I prefer to utilize the term ‘an improved method.’ In my opinion, it is one of the scientific methods for investigating the natural world instead of the absolutely correct way to estimate the average visibility.

Citation: https://doi.org/10.5194/amt-2022-74-RC1
- AC1: 'Reply on RC1', zhang zefeng, 19 May 2022
  
  The comment was uploaded in the form of a supplement: https://amt.copernicus.org/preprints/amt-2022-74/amt-2022-74-AC1-supplement.pdf
  
  Citation: https://doi.org/10.5194/amt-2022-74-AC1
RC2:
'Comment on amt-2022-74', Anonymous Referee #2, 07 Apr 2022

Major comments

This study claims to provide correct algorithm for calculating average visibility. The authors also argued that the methods used in previous studies were not correct.

First of all, I don't agree with the title of the paper. Saying “Average visibility that has been miscalculated” is completely wrong. There is no evidence that previous studies miscalculated visibility, so the paper's title is misleading. I agree with reviewer 1, making the claim that this study provides a correct method is not appropriate, while it may be one of the methods to calculate visibility.

The message of the current manuscript is misleading, therefore it should not be considered for publication. The authors should rewrite the manuscript by proposing their algorithm as one of the methods of calculating visibility. However, again it is a question of how reliable the proposed method is. If the authors take the issue raised carefully and resubmit the manuscript, I can review it again for any possibility of publication in the AMT.

Citation: https://doi.org/10.5194/amt-2022-74-RC2
- AC2: 'Reply on RC2', zhang zefeng, 19 May 2022
  
  The comment was uploaded in the form of a supplement: https://amt.copernicus.org/preprints/amt-2022-74/amt-2022-74-AC2-supplement.pdf
  
  Citation: https://doi.org/10.5194/amt-2022-74-AC2
- AC3: 'Reply on RC2', zhang zefeng, 19 May 2022
  
  The comment was uploaded in the form of a supplement: https://amt.copernicus.org/preprints/amt-2022-74/amt-2022-74-AC3-supplement.pdf
  
  Citation: https://doi.org/10.5194/amt-2022-74-AC3

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload

AR by zhang zefeng on behalf of the Authors (20 May 2022) Author's response Manuscript

ED: Referee Nomination & Report Request started (23 May 2022) by Francis Pope

RR by Anonymous Referee #2 (24 Jun 2022)

Suggestions for revision or reasons for rejection

Review of "Average visibility that has been miscalculated (AMT-2022-74)":

The authors divided the concerns of the reviewers into three questions and answered them by means of some examples. However, the authors fail to improve the manuscript as suggested by the reviewers. The claim that the previous methods were wrong, is not satisfactory! Detailed comments on the authors' responses are below.

Questions 1 – The authors tried to explain through a car travel example that "is this a change from "incorrect" to "correct" or a "general improvement". I don't believe this is the case for visibility calculations and the example given nowhere proves that the previous visibility calculations were incorrect. How did the authors come to the conclusion that the all previous visibility calculations were similar to those in Equation 1 and their Equation 3?

Questions 2 – I agree mathematically their example may be correct but does this example always apply in a real situation where atmospheric visibility cannot be infinite? Therefore, this example does not prove that the previous methods were wrong. I believe previous studies considered atmospheric conditions to calculate visibility and there is always room for improvement in the method depending on the problem and situation.

Questions 3 – I do not agree with the author’s statement - “The argument that "there is no evidence that previous studies miscalculated visibility" does not lead to the conclusion that the algorithm for calculating the average visibility in the past is correct, nor to the conclusion that the title of the manuscript is misleading.” Without any scientific evidence how can the author claim that all the previous methods were wrong? I liked the philosophical statement but it doesn't add anything to support their conclusion.

Comments on the manuscript:
1. Introduction section lacks background and references that should be addressed.
2. Inferences – I don't understand how the differences in equation 7 from equations 6 prove that the algorithm of equation 2 is wrong. It's just a case of two different ways of calculation. Here authors need solid justification.
3. I agree that visibility mainly depends on particles, although studies have shown that gases have non-negligible (about 4-10%) contribution to visibility that needs to be considered.
4. Relative error caused by the erroneous algorithm – This section needs more justifications. Simply, visibility can be calculated using the extinction coefficient at the individual point or the other way around. Furthermore, rather than being called an error, it shows more of a difference in values from methods 2 and 3. Here authors should provide clear and detailed descriptions of equation 9 and results. More experimental (mathematical) examples can help in this direction.
5. Conclusions – This section needs some improvement. Authors are repeating the same message over and over. They should include possible limitations and improvements for both methods.

Overall, I am still not convinced by the authors' claim that the previous methods were wrong and that their method is the only correct method. I still believe that this paper only provides an additional method to calculate visibility, nothing more.

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RR by Anonymous Referee #3 (15 Jul 2022)

ED: Reconsider after major revisions (25 Jul 2022) by Francis Pope

AR by zhang zefeng on behalf of the Authors (20 Sep 2022) Author's response Manuscript

EF by Polina Shvedko (22 Sep 2022) Author's tracked changes

ED: Referee Nomination & Report Request started (22 Sep 2022) by Francis Pope

RR by Anonymous Referee #3 (04 Oct 2022)

RR by Anonymous Referee #2 (06 Oct 2022)

ED: Publish subject to minor revisions (review by editor) (02 Nov 2022) by Francis Pope

AR by zhang zefeng on behalf of the Authors (10 Nov 2022) Author's response Author's tracked changes Manuscript

ED: Publish as is (28 Nov 2022) by Francis Pope

AR by zhang zefeng on behalf of the Authors (01 Dec 2022)

Short summary

In this study, we first analyze the relationship between the visibility, the extinction coefficient, and atmospheric compositions. Then we propose to use the harmonic average of visibility data as the average visibility, which can better reflect changes in atmospheric extinction coefficients and aerosol concentrations. It is recommended to use the harmonic average visibility in the studies of climate change, atmospheric radiation, air pollution, environmental health, etc.