Study of Atomic Oxygen Airglow Intensities and Air Temperature near Mesopause Obtained by Ground-Based and Satellite Instruments above Baikal Natural Territory

Round 1

Reviewer 1 Report

I thank the authors for the clarifications and now I see the reasoning behind certain sections. In general, the updated version of the article makes sense to me, but I’d like to ask the authors to do two more things. Perhaps, this will explain the shift they are writing about. This is a simple exercise, which should not take much of their time, but this will make the conclusions more sound and it will test the atomic oxygen data set (and retrieval technique).

(1) In their Fig. 4 and Fig. 6, they show the OLD and NEW profiles of atomic oxygen from SABER, both of which correspond to model of Mlynczak. However, there is another model, which is mentioned in the article, but the results of which are not included. I speak about (Panka et al., 2018) – the corresponding data set can be downloaded from ftp://saber.gats-inc.com/Version2_0/SABER_atox_Panka/ . It would be interesting to add the corresponding profiles and to discuss how this changes the shifts, etc. The advantage of this data set is that it was built using a self-consistent model of several components and it would be good to test it this way.

(2) If the aforementioned data set does not make the temperature comparison any better, then it would make sense to suggest a profile of atomic oxygen, which would make them closer to each other. This is a legal exercise, because atomic oxygen is a highly variable component, and it would give a hint for the remote sensing researchers, whether they hit or miss the key part of their atomic oxygen profile retrievals.

Author Response

-Thank you for your review. Very helpful remarks and we are grateful for your attention to details.

I thank the authors for the clarifications and now I see the reasoning behind certain sections. In general, the updated version of the article makes sense to me, but I’d like to ask the authors to do two more things. Perhaps, this will explain the shift they are writing about. This is a simple exercise, which should not take much of their time, but this will make the conclusions more sound and it will test the atomic oxygen data set (and retrieval technique).

(1) In their Fig. 4 and Fig. 6, they show the OLD and NEW profiles of atomic oxygen from SABER, both of which correspond to model of Mlynczak. However, there is another model, which is mentioned in the article, but the results of which are not included. I speak about (Panka et al., 2018) – the corresponding data set can be downloaded from ftp://saber.gats-inc.com/Version2_0/SABER_atox_Panka/. It would be interesting to add the corresponding profiles and to discuss how this changes the shifts, etc. The advantage of this data set is that it was built using a self-consistent model of several components and it would be good to test it this way.

-We have add the data and discussion in the manuscript.

(2) If the aforementioned data set does not make the temperature comparison any better, then it would make sense to suggest a profile of atomic oxygen, which would make them closer to each other. This is a legal exercise, because atomic oxygen is a highly variable component, and it would give a hint for the remote sensing researchers, whether they hit or miss the key part of their atomic oxygen profile retrievals.

-We can not in frame of the our manuscript propose the airglow profile as the graph or the table but we discuss possible shape of the profile in the Discussion section, starting from line 401 " Thus, a possible reason for...".

Author Response File: Author Response.docx

Reviewer 2 Report

This manuscript compares the atomic oxygen 557.7 nm airglow as well as the retrieved temperature at the mesosphere obtained from both a ground-based Fabry–Pérot interferometer and SABER aboard of TIMED satellite. The result from the manuscripts are interesting, and give insight into calibration of ground-based instruments based on space based observation for the airglow observations. However, there are some issues which need to be addressed to make the manuscript more acceptable for publication in “remote sensing”. 

 

corrections:

1. Introduction

• While authors mentioned the use of satellite-based observations to optimize the ground-based measurements of atmospheric parameters (e.g., atmospheric temperature) at the mesosphere, the introduction should also mention the possible causes for the discrepancies between the ground-based and space-based measurements, for the previous works.
• The authors should also provide some introductory information on the importance of oxygen (1?)–(1?) 557.7 nm airglow, and it’s importance among other airglow types as a tool for retrieving atmospheric parameters.

1. Materials and Methods
2. Figure 2: It would be better to add another panel presenting the residual temperature between SABER and FPI, so it is easier to compare the two sets of temperatures.
3. Page 7, line 213: “But the resulting … so smooth”. The sentence is vague. What number of profiles? Which profiles? What do you mean by smaller? Be more specific.
4. Page 2, last paragraph: although you mention the linear fit, you should describe the parameters of the fit, a,b, and w, as well as E (is it the error?)
5. Improve the quality of figure 1. Also, correct the color plot label. It should be “Temperature [k]”
6. Page 4. In the description of Figure 1, the authors should explain the reason behind altitude and temperature variation in a periodic manner across the mesopause. There are plenty of references explaining the phenomenon.
7. Page 7. Line 220. “Figure 3(a,b,c)” All of a sudden, there is a sentence about Figure 3 that has been described in the previous page. Also in line 221, “We can note … each parameter is decreasing…”. What parameter are the authors describing? The authors should more specific description of these parameters (assuming they are describing A and f coefficients).
8. Page 7, last paragraph: The authors should describe Figure 5 in more detail. How they obtained the data, presented in Figure 5. For instance “is data in figure 5 obtained from the retrieval of the atomic oxygen using eq (6), as they have mentioned in the subtitle of the figure but in more detail ”. Also, the authors should describe, what is the cause of high atomic oxygen concentration at altitudes between 105-110 km shown at the top panel of figure 5 (calculated from ref [17]) (e.g., similar to the description for figure 4 for altitudes above 100 km ). What is the reason for missing data in the bottom panel of figure 5?
9. Page 8, figure 5, The bottom plot for the concentration of atomic oxygen shows a dramatic temporal and altitudinal change in the concentration (red spots), which seems to be non-physical. I understand that these are obtained from parameters borrowed from reference [18]. However, These can have a large impact if the profiles are integrated. The authors either should improve parameters (e.g., one can use ref [17] (top panel) as the correct assumption for these temporal-altitudinal intervals, find the difference and use a reverse method to improve the coefficients for reference [18]), or the authors should mention this in describing the retrievals from reference [18].
10. Page 8, In eq (7), correct K_5 to K_2. Also, describe C’ coefficients. What are the units for the K_1, K_2, (A_558 nm, A(S^1)). Also, describe Einstein A coefficients are related to which transitions.
11. Page 9, line 260, “It can be seen that …universally accepted concepts.” The description is vague. Which “first approximation” ? be more specific. Also, it seems out of place. Shouldn’t this part be the continuation of the previous paragraph?

3. Results and discussion

1. Page 10, Figure 8: consider the below corrections about figure 8 and its description in the script.

• Shouldn't the label “Intensity IFP” be “Intensity FPI”? if so, correct. (all of the figures with similar label have the same error) Also, it seems that the font sizes for the top and bottom panels are different. Be consistent in the figure presentation.
• It also appears that the intensity units for SABER and FPI are different. Mention the appropriate intensity units on the y axis.
• Elaborate more about figure 8 in the script. Explain the differences between the intensities obtained by using coefficients from refs [17] and [18]. Why is the integrated intensity obtained using coefficients from ref [18] seem to be much higher? (e.g., intensities for August).
• It would be better to add another panel to each panel of figure 8, representing the residual intensity between SABER integrated intensity and FPI.

1. Page 11, Figure 10: consider the below corrections about figure 10 and its description in the script.

• Figure 9 is missing. If there is no figure 9, change the figure numerations, so that figure 10 should be figure 9 and so on.
• In the caption for figure 10 mention the reference from which you calculated the temperatures.
• Similar to the previous figure, be consistent with the font size for the labels.
• Elaborate more on the differences on the temperature retrievals obtained using the coefficients presented in refs [17] and [18].
• Similar to the previous figure, It would be better to add a panel showing the residual temperature between SABER and FPI for both top and bottom panels.

1. Page 13, first paragraph: “Seasonal behavior …. shifted 3 km up…”. The sentence is vague, how did you measure the 3 km shift and what does it mean the 3km shift for temperature?!
2. Page 14. Provide additional references for the explanation for the mechanisms (change in atomic concentration or Barthes mechanism ) that the authors base the reverse correlation between oxygen 557.7 nm and temperature variations registered by the FPI instrument.
3. For a better comparison, I suggest cross-validation scatter plots [including a linear fit] where one axis represents the temperature retrieved from SABER and the other axis represents the temperature retrieved from the FPI instrument [and the corresponding descriptions in the script]. This can apply to Figures 2, 8, 10, 12, and 13.

 

 

 

Minor corrections:

1. It would be better to state reference in the form of (first author + et al.) when possible, rather than article [article #].
2. Page 5: Describe the parameters in equation (1).
3. Page 6: eq (6): describe all the parameters presented in eq 6, including fx and Ax .
4. Page 7, the last paragraph: “The maximum …”. The sentence doesn’t seem to be grammatically correct. I suggest starting with “Figure 5 shows …”.
5. Page 9, line 255, “Like with the oxygen …”. Rephrase to sentence to make it grammatically correct.

 

1. Page 12, figure 11. Use an appropriate label for x-axis “Altitude [km]”

 

 

 

 

General note about the English of the paper:

 

The English need slight improvements, as there are grammatical errors though out the script. I suggest the author read the script over and correct any vague sentences and errors. For example,

There are some extra hyphenations and hyphenation absence throughout the script. Please read the script over and correct for these minor errors.

 

Author Response

-We are grateful to the Reviewer 2 for the valuable corrections and remarks. It has significantly help us to improve the manuscript. Our answers are below.

This manuscript compares the atomic oxygen 557.7 nm airglow as well as the retrieved temperature at the mesosphere obtained from both a ground-based Fabry–Pérot interferometer and SABER aboard of TIMED satellite. The result from the manuscripts are interesting, and give insight into calibration of ground-based instruments based on space based observation for the airglow observations. However, there are some issues which need to be addressed to make the manuscript more acceptable for publication in “remote sensing”.

 

Major corrections:

1. Introduction

• While authors mentioned the use of satellite-based observations to optimize the ground-based measurements of atmospheric parameters (e.g., atmospheric temperature) at the mesosphere, the introduction should also mention the possible causes for the discrepancies between the ground-based and space-based measurements, for the previous works.

-We can not find such a works. If respected Reviewer provide us some links we undoubtedly built them in to context of our manuscript.

• The authors should also provide some introductory information on the importance of oxygen (1?)–(1?) 557.7 nm airglow, and it’s importance among other airglow types as a tool for retrieving atmospheric parameters.

-In the Introduction section (lines 64-79), Data and methods section (line 139 and further, lines 170-179, lines 242-264) we describe the nature and the features and also the need of studying of the 557.7 nm airglow generating by the atomic oxygen. We also added some text in the manuscript.

1. Materials and Methods
2. Figure 2: It would be better to add another panel presenting the residual temperature between SABER and FPI, so it is easier to compare the two sets of temperatures.

-As the time sequences of the temperatures obtained by different instruments are differ by number of measurements the residual temperature will have significant gaps so it will not be presentable. The character of temporal variations in the time sequences discussed is distinguishable without subtraction for our qualitative analysis.

1. Page 7, line 213: “But the resulting … so smooth”. The sentence is vague. What number of profiles? Which profiles? What do you mean by smaller? Be more specific.

-We modified the text.

Page 2, last paragraph: although you mention the linear fit, you should describe the parameters of the fit, a,b, and w, as well as E (is it the error?)
-We modified the text.

1. Improve the quality of figure 1. Also, correct the color plot label. It should be “Temperature [k]”

-Done

1. Page 4. In the description of Figure 1, the authors should explain the reason behind altitude and temperature variation in a periodic manner across the mesopause. There are plenty of references explaining the phenomenon.

-Done

1. Page 7. Line 220. “Figure 3(a,b,c)” All of a sudden, there is a sentence about Figure 3 that has been described in the previous page. Also in line 221, “We can note … each parameter is decreasing…”. What parameter are the authors describing? The authors should more specific description of these parameters (assuming they are describing A and f coefficients).

-We have removed the duplicated text. The parameters mentioned are concentrations air density and temperature.

1. Page 7, last paragraph: The authors should describe Figure 5 in more detail. How they obtained the data, presented in Figure 5. For instance “is data in figure 5 obtained from the retrieval of the atomic oxygen using eq (6), as they have mentioned in the subtitle of the figure but in more detail ”. Also, the authors should describe, what is the cause of high atomic oxygen concentration at altitudes between 105-110 km shown at the top panel of figure 5 (calculated from ref [17]) (e.g., similar to the description for figure 4 for altitudes above 100 km ). What is the reason for missing data in the bottom panel of figure 5?

-We have updated the text.

1. Page 8, figure 5, The bottom plot for the concentration of atomic oxygen shows a dramatic temporal and altitudinal change in the concentration (red spots), which seems to be non-physical. I understand that these are obtained from parameters borrowed from reference [18]. However, These can have a large impact if the profiles are integrated. The authors either should improve parameters (e.g., one can use ref [17] (top panel) as the correct assumption for these temporal-altitudinal intervals, find the difference and use a reverse method to improve the coefficients for reference [18]), or the authors should mention this in describing the retrievals from reference [18].

-We added several sources of information about oxygen retrieved by SABER due to recommendation of academic editor supervised the initial version of the manuscript. The goal of our manuscript is not correction of the coefficients for the oxygen retrieving from SABER data but the some proposal of possible shape of 557.7 nm airglow height profile for possible future modification of the aeromnomical airglow model. We cannot (and have no time now) to open a new research here.

1. Page 8, In eq (7), correct K_5 to K_2. Also, describe C’ coefficients. What are the units for the K_1, K_2, (A_558 nm, A(S^1)). Also, describe Einstein A coefficients are related to which transitions.

-We already add all the links needed with the numerical values of the coefficients and we believe there is no need duplicate it in the our manuscript.

1. Page 9, line 260, “It can be seen that …universally accepted concepts.” The description is vague. Which “first approximation” ? be more specific. Also, it seems out of place. Shouldn’t this part be the continuation of the previous paragraph?

-We modified the text.

1. Results and discussion

1. Page 10, Figure 8: consider the below corrections about figure 8 and its description in the script.

• Shouldn't the label “Intensity IFP” be “Intensity FPI”? if so, correct. (all of the figures with similar label have the same error) Also, it seems that the font sizes for the top and bottom panels are different. Be consistent in the figure presentation.

-Changed

• It also appears that the intensity units for SABER and FPI are different. Mention the appropriate intensity units on the y axis.

-Changed

• Elaborate more about figure 8 in the script. Explain the differences between the intensities obtained by using coefficients from refs [17] and [18]. Why is the integrated intensity obtained using coefficients from ref [18] seem to be much higher? (e.g., intensities for August).

-The differences in the intensities are discussed in Discussion. We propose in our Technical notes manuscript to develop a new photochemical model which remove the discrepancy.

• It would be better to add another panel to each panel of figure 8, representing the residual intensity between SABER integrated intensity and FPI.

-We already mentioned the disadvantage of subtraction procedure with respect to the time sequences with non coinciding data gaps (see above about temperatures sequences).

1. Page 11, Figure 10: consider the below corrections about figure 10 and its description in the script.

 

• Figure 9 is missing. If there is no figure 9, change the figure numerations, so that figure 10 should be figure 9 and so on.

-Done

• In the caption for figure 10 mention the reference from which you calculated the temperatures.

-Done

• Similar to the previous figure, be consistent with the font size for the labels.

-Done

 

• Elaborate more on the differences on the temperature retrievals obtained using the coefficients presented in refs [17] and [18].

-We have added some text.

• Similar to the previous figure, It would be better to add a panel showing the residual temperature between SABER and FPI for both top and bottom panels.

-We already mentioned the disadvantage of subtraction procedure with respect to the time sequences with non coinciding data gaps (see above about temperatures sequences).

 

1. Page 13, first paragraph: “Seasonal behavior …. shifted 3 km up…”. The sentence is vague, how did you measure the 3 km shift and what does it mean the 3km shift for temperature?!

-We modified the text.

1. Page 14. Provide additional references for the explanation for the mechanisms (change in atomic concentration or Barthes mechanism ) that the authors base the reverse correlation between oxygen 557.7 nm and temperature variations registered by the FPI instrument.

-We have added the text.

1. For a better comparison, I suggest cross-validation scatter plots [including a linear fit] where one axis represents the temperature retrieved from SABER and the other axis represents the temperature retrieved from the FPI instrument [and the corresponding descriptions in the script]. This can apply to Figures 2, 8, 10, 12, and 13.

-We can use the scatter plots of temperatures but we prefer compare the data as a time sequences because of the problem of different data gaps already mentioned (the number of data for comparison will be decrease). Additionally to it the residual deviance of the temperatures can increase the dispersion in scatter plots and neutralize the correlation demonstrated.

 

 

 

 

Minor corrections:

1. It would be better to state reference in the form of (first author + et al.) when possible, rather than article [article #].
2. Page 5: Describe the parameters in equation (1).
3. Page 6: eq (6): describe all the parameters presented in eq 6, including fx and Ax .
4. Page 7, the last paragraph: “The maximum …”. The sentence doesn’t seem to be grammatically correct. I suggest starting with “Figure 5 shows …”.
5. Page 9, line 255, “Like with the oxygen …”. Rephrase to sentence to make it grammatically correct.

 

1. Page 12, figure 11. Use an appropriate label for x-axis “Altitude [km]”

 

General note about the English of the paper:

 

The English need slight improvements, as there are grammatical errors though out the script. I suggest the author read the script over and correct any vague sentences and errors. For example,

There are some extra hyphenations and hyphenation absence throughout the script. Please read the script over and correct for these minor errors.

-All the minor corrections was taken in to account and fixed.

 

Author Response File: Author Response.docx

Reviewer 3 Report

Review of " Study of atomic oxygen airglow and air temperature near mesopause obtained by ground-based and satellite instruments above Baikal natural territory." by Saunkin et al.

 

Major Comment:

The prime objective of this manuscript is to compare the atomic oxygen airglow intensities and night atmospheric temperature at mesopause derived from satellite and gourd-based instruments. Key results from the observations and comprehensive analysis indicate that the temperature data from SABER/TIMED are in good agreement with Fabry-Perot data when the intensity peak was shifted to 97 km. In other conditions, they didn’t show great consensus. On the other hand, the atomic oxygen airglow intensities from satellite and ground-based instruments are in good consistency.

I suggest to refine the second section, ‘Materials and Method’, in this work. The results shown in figures should be altered into the ‘Results’ section. It’s better to separate the results and discussion to be more formal. Plus, the references should be in alphabetic sequence and be cited with the abbreviation of authors’ names rather than numbers.

Overall, this work still needs much modification before being accepted. I suggest the author to modify the vocabulary and the structure of this work to make it briefer and more academic. You can ask your colleagues for help. I attach comments below that I hope will be helpful to the authors and editors.

 

Specific Comments:

1. 1 Line 2 in Title: Please check if the title should be ‘Study of atomic oxygen airglow intensities …’.
2. 1 Line 10 in Abstract: I suggest to alter ‘deal with’ to ‘study’.
3. 1 Line 15 in Abstract: I suggest to change the word ‘correct’ to another one such as ‘appropriate’.
4. 1 Line 15 to Line 16 in Abstract: “… to make a comparison between…” I suggest that the author can convey the similar meaning in a briefer way, like “between the upper atmospheric temperature obtained from ground-based observations and that from satellite at a particular height”.
5. 1 Line 22 in Abstract: I suggest to replace “that were obtained with SABER” with ‘from SABER’.
6. 1 Line 29 in Abstract: The pronoun, ‘it’, should be ‘them’.
7. 1 Line 38 in Introduction: I suggest to add a word, ‘specially’, between ‘the Earth's atmosphere’ and ‘the upper atmosphere’.
8. In the Introduction, I suggest to add some results of the literature you cited and show the logical connection between different literature.
9. 2 Line 72 in Introduction: I suggest to change ‘we will assess’ to ‘we assessed’.
10. 2 Line 78 in Introduction: The sentence shouldn’t be in the future tense since you have finished this work.
11. 2 Line 72: I suggest to name the title of section two as ‘Data and Methods’.
12. 2 Line 98: I suggest to write the equation in a new line.
13. 4 Line 127 in Figure 1: Figure 1 is not as clear as others. Please check whether this image is in the same format as others.
14. 4 Line 137: The unit of temperature should be ‘K’. Please correct the unit in the following part as well.
15. 4 Line 141: Please add ‘in’ between ‘FPI’ and ‘Figure 2’.
16. 5 Line 142 in Figure 2: Please describe the content of Figure 2 below the illustration.
17. 5 Line 152 in Equation 1: Please make sure that the equations are in middle of the line. Please regulate other equations in the same way.
18. 5 Line 155: It’s sightly informal to use ‘if’ here.
19. 7 Line 203 in Figure 4: Please refine the y axis to make this figure more aesthetic. Figure 6 can be refined in the same way.
20. 7 Line 210: Grammatical error. The word ‘there’ should be changed to ‘it’.
21. 9 Line 251: There are two curves in Figure 6 so I suggest to use the word ‘profile’ in the plural.
22. 9 Line 253: The utility of ‘we can mention that’ is sightly informal.
23. 10 Line 276: The word, ‘must’, is sightly informal.
24. 11 Line 288: The article, ‘the’, cannot be omitted before the word ‘behavior’. Please check the similar mistakes in the following part of this paper.
25. 12 Line 304: The expression ‘let us assume’ is informal. Please replace it by ‘assuming’.
26. 13 Line 328: The word ‘than’ is missing after ‘better’.
27. 13 Line 339: “The obtained better…” This sentence is a little confusing. Please refine to make it more understandable.
28. 14 Line 370: I suggest to replace ‘Figure 9-10’ by ‘Figure 9 and 10’.

 

Comments for author File: Comments.docx

Author Response

-We are grateful to the Reviewer 3 for the valuable Specific Comments and remarks directed to the improvement of our manuscript. Our answers are below.

Major Comment:

The prime objective of this manuscript is to compare the atomic oxygen airglow intensities and night atmospheric temperature at mesopause derived from satellite and gourd-based instruments. Key results from the observations and comprehensive analysis indicate that the temperature data from SABER/TIMED are in good agreement with Fabry-Perot data when the intensity peak was shifted to 97 km. In other conditions, they didn’t show great consensus. On the other hand, the atomic oxygen airglow intensities from satellite and ground-based instruments are in good consistency.

I suggest to refine the second section, ‘Materials and Method’, in this work. The results shown in figures should be altered into the ‘Results’ section. It’s better to separate the results and discussion to be more formal. Plus, the references should be in alphabetic sequence and be cited with the abbreviation of authors’ names rather than numbers.

-The plots in the Data and Methods (Materials and Methods in old version) are namely materials for our study. Our main results are the temperature and intensity of 557.7 airglow. Atomic oxygen is the input data so we believe it should be described in the Data and Methods.

-We have moved the discussion of the obtained intensity profiles to the discussion section.

-The requirement of Remote Sensing is the numerical links to the literature sources.

Overall, this work still needs much modification before being accepted. I suggest the author to modify the vocabulary and the structure of this work to make it briefer and more academic. You can ask your colleagues for help. I attach comments below that I hope will be helpful to the authors and editors.

 

Specific Comments:

1. 1 Line 2 in Title: Please check if the title should be ‘Study of atomic oxygen airglow intensities …’.
2. 1 Line 10 in Abstract: I suggest to alter ‘deal with’ to ‘study’.
3. 1 Line 15 in Abstract: I suggest to change the word ‘correct’ to another one such as ‘appropriate’.
4. 1 Line 15 to Line 16 in Abstract: “… to make a comparison between…” I suggest that the author can convey the similar meaning in a briefer way, like “between the upper atmospheric temperature obtained from ground-based observations and that from satellite at a particular height”.
5. 1 Line 22 in Abstract: I suggest to replace “that were obtained with SABER” with ‘from SABER’.
6. 1 Line 29 in Abstract: The pronoun, ‘it’, should be ‘them’.
7. 1 Line 38 in Introduction: I suggest to add a word, ‘specially’, between ‘the Earth's atmosphere’ and ‘the upper atmosphere’.
8. In the Introduction, I suggest to add some results of the literature you cited and show the logical connection between different literature.
9. 2 Line 72 in Introduction: I suggest to change ‘we will assess’ to ‘we assessed’.
10. 2 Line 78 in Introduction: The sentence shouldn’t be in the future tense since you have finished this work.
11. 2 Line 72: I suggest to name the title of section two as ‘Data and Methods’.
12. 2 Line 98: I suggest to write the equation in a new line.
13. 4 Line 127 in Figure 1: Figure 1 is not as clear as others. Please check whether this image is in the same format as others.
14. 4 Line 137: The unit of temperature should be ‘K’. Please correct the unit in the following part as well. (Я не поняла, где это, может к красной подписи в рис 1)
15. 4 Line 141: Please add ‘in’ between ‘FPI’ and ‘Figure 2’.
16. 5 Line 142 in Figure 2: Please describe the content of Figure 2 below the illustration.
17. 5 Line 152 in Equation 1: Please make sure that the equations are in middle of the line. Please regulate other equations in the same way.
18. 5 Line 155: It’s sightly informal to use ‘if’ here.
19. 7 Line 203 in Figure 4: Please refine the y axis to make this figure more aesthetic. Figure 6 can be refined in the same way.
20. 7 Line 210: Grammatical error. The word ‘there’ should be changed to ‘it’.
21. 9 Line 251: There are two curves in Figure 6 so I suggest to use the word ‘profile’ in the plural.
22. 9 Line 253: The utility of ‘we can mention that’ is sightly informal.
23. 10 Line 276: The word, ‘must’, is sightly informal.
24. 11 Line 288: The article, ‘the’, cannot be omitted before the word ‘behavior’. Please check the similar mistakes in the following part of this paper.
25. 12 Line 304: The expression ‘let us assume’ is informal. Please replace it by ‘assuming’.
26. 13 Line 328: The word ‘than’ is missing after ‘better’.
27. 13 Line 339: “The obtained better…” This sentence is a little confusing. Please refine to make it more understandable.
28. 14 Line 370: I suggest to replace ‘Figure 9-10’ by ‘Figure 9 and 10’.

 

-All the discrepancies from Specific Comments was fixed in the manuscript.

 

Author Response File: Author Response.docx

Reviewer 4 Report

The paper demonstrates an effort of new step in utilizing measurements of the oxygen green line for monitoring of the upper atmosphere.  It may be interesting for specialists engaged in measurements and modeling of airglow.

Some improvements are required or recommended. 

MAJOR COMMENTS

1. CONCLUSIONS should be rewritten to provide a list of the new findings, in  shorter phrases
2. Line 138: " It is universally accepted that the height of the 557.7 nm atomic oxygen line airglow 138 is at 95–97 km [15, 16]". There must be more exact words - PEAK HEIGHT. Problem connected with upper thermosphere contribution to the green line under ground-based observations [16] and its contribution to the obtained temperature are not mentioned.
3. A contribution of Chapman (O+O+O) mechanism of the green line excitation (as an additional source of the green line) is not discussed. 

MINOR COMMENTS

1. Line 172. Barthes --> Barth
2. Line 110. Density of density - what does it mean?
3. Lines 215, 298. dispersion ->variance
4. Line 244. k2--> k5
5. Fig 8: No units for intensities
6. Please renumber figures (no Fig 9) 
7. Line 53. Maigama --> Maimaga. Is it really mid-latitude?

Author Response

-We are grateful to the Reviewer 4 for the valuable comments and remarks for improvement of our manuscript. Our answers are below.

The paper demonstrates an effort of new step in utilizing measurements of the oxygen green line for monitoring of the upper atmosphere.  It may be interesting for specialists engaged in measurements and modeling of airglow.

Some improvements are required or recommended. 

MAJOR COMMENTS

1. CONCLUSIONS should be rewritten to provide a list of the new findings, in shorter phrases

-We have split the text in to several paragraphs with main points of the research inside.

1. Line 138: " It is universally accepted that the height of the 557.7 nm atomic oxygen line airglow 138 is at 95–97 km [15, 16]". There must be more exact words - PEAK HEIGHT. Problem connected with upper thermosphere contribution to the green line under ground-based observations [16] and its contribution to the obtained temperature are not mentioned.

-We have correct the text and expand discussion of different mechanism with corresponding links in the Data and Methods section.

1. A contribution of Chapman (O+O+O) mechanism of the green line excitation (as an additional source of the green line) is not discussed. 

-We have expand discussion about two concurrent chemical mechanisms in Data and method section.

MINOR COMMENTS

1. Line 172. Barthes --> Barth
2. Line 110. Density of density - what does it mean?
3. Lines 215, 298. dispersion ->variance
4. Line 244. k2--> k5
5. Fig 8: No units for intensities
6. Please renumber figures (no Fig 9) 
7. Line 53. Maigama --> Maimaga. Is it really mid-latitude?

 

-All the discrepancies from Minor Comments was fixed in the manuscript.

 

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

The authors have made all changes that I suggested, I think the paper should be accepted. I do not think that it is necessary for me to see the paper again.

Reviewer 4 Report

My previous comments have been taken into account. The new version seems to be much better and almost ready for publishing. The only small problem noticed in the new version is with dimensions, units and legends in Figures 8 and 12.  Please check where must be INTENSITY, where must be VER and units for them. 

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

General comments

The manuscript seeks to understand whether the nighttime airglow measurements at 557.nm performed by ground-based interferometer are consistent with the observations of the same area by a SABER instrument onboard TIMED satellite. Indeed, if both measurements are correct and our understanding of the physical processes occurring at these heights is complete, we should obtain a coherent picture. If there is a discrepancy, one has to find a reason and fix it. From this point of view, the manuscript is interesting, but the approach outlined in the manuscript has several significant deficiencies, which prevent me from recommending to publish the manuscript in its present form.

First, in their previous work [17] the authors already used SABER to validate their observations. This time, they do the opposite: they compare the airglow modeled using SABER atmospheric profiles and measured by the ground-based interferometer and from this comparison they deduce that SABER profiles have to be changed. However, performing this “cross-calibration” is not fair, it’s just like solving the system of M equations and N variables when N>M.

Second, not all the SABER retrievals are performed on individual channels, and the authors already mention [20] for atomic oxygen retrieval. However, they did not notice that several channels are intertwined through physical interactions in the atmosphere and one cannot change one vertical profile without modifying the other ones. Here, I speak about the “shifting” mentioned in the manuscript – if one shifts the simulated radiance profile, this must change atomic oxygen, which will affect temperature retrievals (look for “CO2 quenching in the mesosphere” articles). This exercise, therefore, is purely technical and has no scientific value. I agree that one can try to match the profiles and make the conclusions based on the results, but the analysis must be much more complex as it involves non-LTE modeling. I understand that this is outside the domain of the authors’ domain of expertise, but it doesn’t make the problem solvable in one “shift”. Something more elaborated is needed here.

Third, the effective temperature calculations introduced by Eq. 1 will work correctly only for tiny variations of temperature of strongly contributing atmospheric layers. Doppler half width dependence on temperature is not linear at all and one can easily show for a case of two layers with equal values of V558 that the temperature estimated from a halfwidth of a joint profile will not be equal to the average temperature. The difference is quite large to use the approach described in the manuscript. For an exercise, I took T1=175K, T2=245K for two equally contributing layers and obtained 203.3 K from a joint half-width instead of 210K. If the difference between T1 and T2 is smaller, the discrepancy will be smaller, too, but the solution should be general.

   

Specific comments

Lines 1−4: The title has to be changed. One cannot compare airglow and temperature (it’s like comparing kilometers and kilograms). The same (formally logical, but still annoying) mistake is repeated elsewhere in the manuscript.

Lines 90−91: here, the authors refer to “calibrating B using A” and later in the article they use B to update A that is not fair.

Lines 102−103: I understand the authors started working with the initial version of the data, but V.2.0 is available at the Web site of SABER for quite a while, and in the meantime SABER Team reported the updates related both to L1 improvement (spectral leaks defined and removed) and to L2 reprocessing. I do not see any point in keeping the old version in the analysis.

Line 127: probably, there’s a typo in winter mesopause temperature value

Lines 136−148: the definitions should precede the main text. In addition, the definition itself need to be updated, see the general comment #3.

Lines 150−155: why the “reconstruction” is needed here whereas atomic oxygen is an available in the SABER’s data?

Lines 156−164: this part belongs to the introduction

Lines 192−193: the statement requires some proof and/or explication

Lines 196−198: this is not a good explanation because both O3 and P decrease when the airglow signal decrease. There might be over- or under-compensation of these effects, but qualitatively they move in same direction.

Lines 260−271: please, see the comments regarding the “shifting” above.

Lines 312−336: here’s a sum of the statements already discussed above.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

This paper compares mesospheric temperature observes with Fabry-Perot interferometer and SABER, and discuss the reason of the discrepancy between the two temperatures. The result is important and could contribute to the studies of the mesopause regions. However, the following comments need to be addressed before its publication.

- l. 127, "175°K in summer, and 145°K in winter": 
   -->  175°K in winter, and 145°K in summer

- Figure 1 and related text:
Describe an altitude at which the SANER temperature is taken.

- l. 158: "4,2 eV" may be "4.2 eV".

- figure caption of Figure 3.
Describe accurately.  Is the euantity shown in Figure 3b mixing ration of ozone or ozone density?
Unit of the quantity also needs to be shown. 

- The authors have calculated the volume emission rate from the atomic oxygen data obtained by the SABER measurements. Is the calculated volume emission rate consistent with altitude profile of the airglow intensity directly observed with the SABER?
 
- l. 275. "The minimum of the error weighting function falls on the height of ~97 km.":
Altitude of the airglow layer change with season. Does the authors consider the seasonal variation of the airglow layer altitude? Seasonal variation of the temperature observed with FPI does not represent the seasonal variation of the temperature at a fixed altitude, and is affected by the seasonal variation of the airglow layer altitude.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

The authors present a comparison of data from the KEO Scientific Arinae FPI to data from SABER. Specifically, they determine an Effective Temperature from the SABER data and note that it is inconsistent with the FPI data in regards to seasonal variations. Assuming that the peak in green line emission is 3km higher than SABER reports, they re-calculate a new Effective Temperature and show that it has better agreement with the temperatures derived from the ground-based FPI, at least for several months out of the year (Jan - June).  

I recommend this paper for publishing with some minor changes listed below. 

As a reader, I'd be curious to know if there was an airglow altitude shift for which the other months (July - Dec) are in better agreement. One could limit the data set to these months and perform the same experiment.

Reference [22] is the same as Reference [11].  

Line 43: Consider replacing "Thus, the article [1]" with "For example, Cheng et al [1] describe" or "For example, Article [1]"

Line 189: "At a Figure 3(a)" is incorrect.  Consider "In Figure 3(a)".

Line 243: I assume "have decreased their dispersion" means "have reduced scatter"?

Line 311: "Lef" should be "Left"

Line 318: I suggest: "However, taking into account the glow intensity height profile, which allows for correct comparison of data...
instruments, led to a"

Line 385: Is reference [13] complete? It looks cut off.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

General comments

This is a second review. Formally, the authors answered the questions and addressed the comments, but in reality, the changes are superficial and the core of the problem remained, so I still cannot recommend the publication of this manuscript in its present form.

Let’s go once again over the questions and answers.

1. Cross-validation of A vs B with a consequent B vs A validation is not convincing. I understand that the first validation was based on minimizing the seasonal variations of temperatures, but this task is ill posed. SABER temperatures in this area depend on atomic oxygen, so one cannot retrieve atomic oxygen profile independently from a measurement, which uses temperatures. In addition, the way the authors build their weighted sum of temperatures (Eq. 1) is not correct, and I wrote about it in my third paragraph. The methodological paper like this one should start with a self-consistent theoretical retrieval algorithm, where everything is under the author’s control and where one can estimate the uncertainties. At the moment, the manuscript describes some technical approach, which is a kind of working, but which is not rigorous and it is not pedagogical for a student or for a young specialist. I would start with a demonstration of the approach using standard atmosphere and simulated measurements with their uncertainties and show that the solution is unique.
2. The shifting procedure problem remains — the authors admit it has no physical meaning given that the rest of the retrieved atmosphere will change. Actually, the second problem is linked to the first one. If the self-consistent retrieval scheme was developed, it would have eliminated the need for vertical shifts.
3. I repeat here that the effective temperature calculations introduced by Eq. 1 will work correctly only for tiny variations of temperature of strongly contributing atmospheric layers. The authors replied they did not understand the question and from their answer I see they consider a “layer” in my comment as a whole emitting one whereas I spoke about the finer structure. In the numerical solution of radiative transfer equation in a plane-parallel atmosphere, the atmospheric column is considered as a set of layers of constant temperature, pressure, and trace gas concentrations. From this point of view, the emitting “layer” modeled by the authors comprises several sub-layers of different temperature. The detected signal (or line shape) will represent a superposition of these layers and in the first review I showed that the simplistic summing performed by the authors using their Eq. 1 will give an error in retrieved temperature. I understand that building a full self-consistent model is difficult for the authors, but performing a correct weighted summing is definitely feasible. I suspect that this might reduce the value of the shift needed to fit the data.

Summing up, I do not see how the atmospheric community will profit from publishing the manuscript without the changes I suggest. Even though it is a technical note, it should bring something new to the field that could be applied elsewhere. I suggest the authors to put themselves in the shoes of a researcher who does not perform the FPI measurements and consider what will he/she learn from this manuscript? How will this knowledge be used and where? Shifting the atmospheric profile to fit temperature is not a valid physical approach, and it is not a valid technical approach, either.   

 

Specific comments

Lines 1−4: I repeat, one cannot compare airglow and temperature. These are different physical values with different units and different meaning. One can establish a link between them or study, or just list them in one line without “comparing”.

Lines 102-103: this was a comment regarding the version of SABER data. The authors replied that when they worked with SABER data, the new version was not available. This might be true, but this should have been a long time ago. I do not see any point in discussing the results for the data, which has not been recalibrated and updated given that the new version exists.

 

Author Response

- We are very grateful to the reviewer for his attention to our work. Below we
will cite the text of the review and consistently respond to comments.
“This is a second review. Formally, the authors answered the questions and
addressed the comments, but in reality, the changes are superficial and the core of
the problem remained, so I still cannot recommend the publication of this manuscript
in its present form.
Let’s go once again over the questions and answers.
Cross-validation of A vs B with a consequent B vs A validation is not convincing. I
understand that the first validation was based on minimizing the seasonal variations
of temperatures, but this task is ill posed. “
- Yes, the procedure described is wrong. But first we got the A using B and
then we compare A with B taking into account C. Where C is the height profile
of the emission.
“ SABER temperatures in this area depend on atomic oxygen, so one cannot retrieve
atomic oxygen profile independently from a measurement, which uses temperatures.
In addition, the way the authors build their weighted sum of temperatures (Eq. 1) is
not correct, and I wrote about it in my third paragraph. The methodological paper like
this one should start with a self-consistent theoretical retrieval algorithm, where
everything is under the author's control and where one can estimate the
uncertainties. At the moment, the manuscript describes some technical approach,
which is a kind of working, but which is not rigorous and it is not pedagogical for a
student or for a young specialist. I would start with a demonstration of the approach
using standard atmosphere and simulated measurements with their uncertainties and
show that the solution is unique.”
- We do not reconstruct the temperature or emission intensity at selected height
(or heights) based on the FPI data, we adapt the SABER data to compare
with the parameters FPI gets. The effective temperature discussed is the
parameter that comes from FPI measurements naturally, because FPI sees
all the airglow column and the temperature retrieved from FPI is the sum of
temperatures along column with weights corresponding to intensities at each
height. We retrieve effective temperature from SABER data and compare it
with the effective temperature measured by FPI. We use technical methods
from previous studies already published (see [6] Liu, W., Xu, J., Smith, A. K.,
& Yuan, W. (2015) Comparison of rotational temperature derived from
ground-based OH airglow observations with TIMED/SABER to evaluate the
Einstein coefficients. Journal of Geophysical Research: Space Physics,
120(11), 10069–10082. doi:10.1002/2015ja021886 in the manuscript)
Therefore we do not need to examine them in our manuscript (but we updated
the text of manuscript). The procedure of comparison was done for hydroxyl
emission, but for the green airglow similar procedure was not performed ever.
So we think the studies done are rather important for the atmospheric
community and especially for the FPI users. We do not try to figure out some
complete and fundamental text (like in the readbooks) we just inform the
community about studies done. Why it is important. The calibration source for 
FPI has a wavelength far from 557.7 and it can be the reason for systematic
shifts. We demonstrate how one may cancel it for any other needs.
“The shifting procedure problem remains - the authors admit it has no physical
meaning given that the rest of the retrieved atmosphere will change. Actually, the
second problem is linked to the first one. If the self-consistent retrieval scheme was
developed, it would have eliminated the need for vertical shifts.”
- We completely agree with the reviewer here. But using this non physical
approach we try to direct the algorithm before development. We just say:”If
someone starts to develop the procedure for retrieving the height profile of the
green emission line please watch the position of the profile maximum.
Apparently it should be close to 97 km, and should vary during the seasons”.
“I repeat here that the effective temperature calculations introduced by Eq. 1 will work
correctly only for tiny variations of temperature of strongly contributing atmospheric
layers. The authors replied they did not understand the question and from their
answer I see they consider a “layer” in my comment as a whole emitting one whereas
I spoke about the finer structure. In the numerical solution of radiative transfer
equation in a plane-parallel atmosphere, the atmospheric column is considered as a
set of layers of constant temperature, pressure, and trace gas concentrations. From
this point of view, the emitting “layer” modeled by the authors comprises several sublayers of different temperature. The detected signal (or line shape) will represent a
superposition of these layers and represent in the first review I showed that the
simplistic summing performed by the authors using their Eq. 1 will give an error in
retrieved temperature. I understand that building a full self-consistent model is
difficult for the authors, but performing a correct weighted summing is definitely
feasible. I suspect that this might reduce the value of the shift needed to fit the data.”
- In our study we did exactly the procedure described by the reviewer for
SABER data and compared the obtained result with the data obtained by FPI
(see both underscore reviewer’s text and also our answer above). The
similarity in the intensities can be the mark of rightness of our approach. The
discrepancy in the temperatures was surprising and we made an almost
unreasonable shifting of the profile in height. This brought us to the similarity
in temperatures and the error function was not randomly distorted, has no
several minima due to dispersion in the input data data but has a main
minimum near 97 km. We again were surprised and we decided to share our
results within the atmospheric community.
“Summing up, I do not see how the atmospheric community will profit from publishing
the manuscript without the changes I suggest. Even though it is a technical note, it
should bring something new to the field that could be applied elsewhere. I suggest
the authors to put themselves in the shoes of a researcher who does not perform the
FPI measurements and consider what will he / she learn from this manuscript? How
will this knowledge be used and where? Shifting the atmospheric profile to fit
temperature is not a valid physical approach, and it is not a valid technical approach,
either.”
- We hope our study will be interesting for the FPI users and people whose
research includes comparison of satellite and ground-based instruments. We 
hope they are meaningful part of the atmospheric community. And we hope
any research can be slightly restricted by the specific area to attract only part
of "Remote Sensing" readers. We think this article will be useful for
demonstrating the capabilities of the interferometer. In our opinion, the
measurement of green emission by an interferometer (FPI) and the
restoration of the green line temperature are underestimated. There are few
works on the green emission of IFPs in the world. The advantage of the FPI is
that it allows simultaneous estimation of wind and temperature in the
mesosphere and lower thermosphere, in contrast to radars and
spectrometers. We think that in the future, ground-based instruments will be
very useful in creating reanalyses for the upper atmosphere. Of course, we
understand that we have only taken the first step in comparing the IFP and
satellite data, in the future, we will improve the methodology and, perhaps,
learn how to more correctly attract data.
Lines 1−4: I repeat, one cannot compare airglow and temperature. These are different
physical values with different units and different meaning. One can establish a link
between them or study, or just list them in one line without “comparing”.
- We agree that the title sounds ambiguous, so we changed the title.
Lines 102-103: this was a comment regarding the version of SABER data. The authors
replied that when they worked with SABER data, the new version was not available.
This might be true, but this should have been a long time ago. I do not see any point in
discussing the results for the data, which has not been recalibrated and updated given
that the new version exists.
- Apparently there was a misunderstanding here. Actually the version that we
used is 2.0. Initially we talked about sub versions of the files of this version.
We supplemented the text to clarify the situation with versions of data. Using
different subversions for our data selection criteria and data processing
procedure do not lead to the significant distortion of the results affecting the
main conclusions.

Author Response File: Author Response.pdf