Himawari-8/AHI and MODIS Aerosol Optical Depths in China: Evaluation and Comparison
Round 1
Reviewer 1 Report
I have attached my comments in pdf file.
Comments for author File: 
Comments.pdf
Author Response
Dear Reviewer 1,
Thank you for taking time and effort to review the previous version of the manuscript. Your excellent and professional suggestions help us a lot. We have worked hard to revise our manuscript. Appended to this letter is our point-by-point response to the comments. The comments are reproduced and our responses are given directly afterward in a different color (red).
We have uploaded a copy of original manuscript with all the changes highlighted by using the track changes mode in MS Word. According to comments by raised by all reviewers, we have made major modifications in a revised version of the manuscript, here we list them briefly:
1. The language has been edited by a native English speaker.
Section 1 Introduction:
2. Rewrite the importance and current state of AHI AOD evaluation studies.
Section 2 Materials and Methods
3. Explain reasons of why we chose the following variables: AERONET AOD, Ångström Exponent, NDVI to analyze the dependency of accuracy.
Section 3 Result:
4. Change a color scale, add north arrow and scales in Figure 3 and fix a mistake in Figure 7.
Section 4 Discussion:
5. Discuss difference between our result and previous study and make hypotheses for the observed features.
6. Give a brief introduction of RF analysis, a graphical depiction of this model and how it was implemented.
7. Clarify the limitations of our study.
Again, thank you very much for giving us the opportunity to improve our manuscript with your valuable comments. We look forward to hearing from you regarding our submission. We would be glad to respond to any further questions and comments.
Best regards,
Tingting Jiang
Author Response File: Author Response.pdf
Reviewer 2 Report
This is a well motivated study which is well presented and has a thorough evaluation of the Himawari-8 AOD retrieval (with relevant metrics as well as temporal and spatial consideration including collocation of data) with respect to AERONET data and also a comparison with the MODIS Deep Blue Products. My only suggestion is that the authors provide a good resolution to the accuracy issues with a Random Forest (RF) analysis in the discussion section. It would be useful to the readers if they provide a few more paragraphs on a brief introduction of RF analysis, a graphical depiction of this model and how it was implemented. After this minor revision, I would recommend it for publication.
Author Response
Dear Reviewer 2,
Thank you for taking time and effort to reviewing the previous version of the manuscript. Your encouraging men and professional suggestions help us a lot. We have worked hard to revise our manuscript. Appended to this letter is our point-by-point response to the comments. The comments are reproduced and our responses are given directly afterward in a different color (red).
We have uploaded a copy of original manuscript with all the changes highlighted by using the track changes mode in MS Word. According to comments by raised by all reviewers, we have made major modifications in a revised version of the manuscript, here we list them briefly:
1. The language has been edited by a native English speaker.
Section 1 Introduction:
2. Rewrite the importance and current state of AHI AOD evaluation studies
Section 2 Materials and Methods
3. Explain reasons of why we chose the following variables: AERONET AOD, Ångström Exponent, NDVI to analyze the dependency of accuracy.
Section 3 Result:
4. Change a color scale, add north arrow and scales in Figure 3 and fix a mistake in Figure 7
Section 4 Discussion:
5. Discuss difference between our result and previous study and make hypotheses for the observed features
6. Give a brief introduction of RF analysis, a graphical depiction of this model and how it was implemented
7. Clarify the limitations of our study.
Again, thank you very much for giving us the opportunity to improve our manuscript with your valuable comments. We look forward to hearing from you regarding our submission. We would be glad to respond to any further questions and comments.
Best regards,
Tingting Jiang
Author Response File: Author Response.pdf
Reviewer 3 Report
p { margin-bottom: 0.1in; line-height: 120%; }While I generally think the article is worthy of publication, it contains a number of weaknesses which I think deserve to be corrected before publication.
General points:
- The language needs to be significantly improved before publication, as language deficiencies make the article difficult to read/understand. I recommend editing by a native English speaker.
- You mention that there are 23 AERONET sites used across China. However, these are not distributed randomly but are very clustered (see e.g. Taiwan). The impact of this clustering on the analysis should be discussed.
- Where do regional difference come from? Taking XiangHe and Bejing as examples, why is so different performance found for these two stations located in rather close vicinity. At least an attempt should be made to give explanations!
- Your validation results use linear regression including an offset, while a zero-offset is to be expected. Please motivate this choice. What would be the outcome if the offset was excluded from the regression?
- The article uses the MODIS Deep Blue product, while also the Dark Target product is available. This choice needs to be motivated. What would change if the Dark Target/Merged products were used instead?
- While the validation statistics are interesting, the article is generally lacking attempts to physically make sense of the statistics. Please try to at least name hypotheses for the observed features. Also, a description of the methods used by the compared articles is missing, including the differences which could explain the observed deviations (in particular: what are the assumptions on aerosol optical properties)
- Tables: please report numbers only up to significant digits. I do not think the 2nddecimal e.g. for reporting the fraction below/within/above EE intervals meaningful.
L161: Why do you use different region areas for AHI and MODIS? Why do you not use e.g. 30x30km2 for both datasets? Are your results sensitive to this choice?
L171: Where is a “quadratic fit” used here? Eq. 1 does not contain any quadratic terms, this needs to be changed/explained better!
L211: “manifesting that a significant improvement … has been made.” What has changed between these versions, can you attribute this improvement to specific algorithm changes? It would be helpful to identify what the reason for this improvement is.
Table 4: why is the correlation lowest at 14:00CST, why does the bias change? Could this be an artefact of errors in cloud masking?
Author Response
Dear Reviewer 3,
Thank you for taking time and effort to reviewing the previous version of the manuscript. Your encouraging comments and professional suggestions help us a lot. We have worked hard to revise our manuscript. Appended to this letter is our point-by-point response to the comments. The comments are reproduced and our responses are given directly afterward in a different color (red).
We have uploaded a copy of original manuscript with all the changes highlighted by using the track changes mode in MS Word. According to comments by raised by all reviewers, we have made major modifications in a revised version of the manuscript, here we list them briefly:
1. The language has been edited by a native English speaker.
Section 1 Introduction:
2. Rewrite the importance and current state of AHI AOD evaluation studies
Section 2 Materials and Methods
3. Explain reasons of why we chose the following variables: AERONET AOD, Ångström Exponent, NDVI to analyze the dependency of accuracy.
Section 3 Result:
4. Change a color scale, add north arrow and scales in Figure 3 and fix a mistake in Figure 7
Section 4 Discussion:
5. Discuss difference between our result and previous study and make hypotheses for the observed features
6. Give a brief introduction of RF analysis, a graphical depiction of this model and how it was implemented
7. Clarify the limitations of our study.
Again, thank you very much for giving us the opportunity to improve our manuscript with your valuable comments. We look forward to hearing from you regarding our submission. We would be glad to respond to any further questions and comments.
Best regards,
Tingting Jiang
Author Response File: Author Response.pdf
Reviewer 4 Report
The statistics applied is not correct and therefore the results obtained are not reliable.
Authors should read the papers:
1) Cantrell, C.A., 2008. Review of methods for linear least-squares fitting of data and application to atmospheric chemistry problems. Atmospheric Chemistry and Physics, 8(17), pp.5477-5487.
2) COMMENT Five ways to fix statistics
558 | NATURE | VOL 551 | 30 NOVEMBER 2017.
(Find it please attached)
Comments for author File: Comments.pdf
Author Response
Dear Reviewer 4,
Thank you for taking time and effort to reviewing the previous version of the manuscript. Your comments and attached references help us a lot. We have worked hard to revise our manuscript . Appended to this letter is our point-by-point response to the comments. The comments are reproduced and our responses are given directly afterward in a different color (red).
We have uploaded a copy of original manuscript with all the changes highlighted by using the track changes mode in MS Word. According to comments by raised by all reviewers, we have made major modifications in a revised version of the manuscript, here we list them briefly:
1. The language has been edited by a native English speaker.
Section 1 Introduction:
2. Rewrite the importance and current state of AHI AOD evaluation studies
Section 2 Materials and Methods
3. Explain reasons of why we chose the following variables: AERONET AOD, Ångström Exponent, NDVI to analyze the dependency of accuracy.
Section 3 Result:
4. Change a color scale, add north arrow and scales in Figure 3 and fix a mistake in Figure 7
Section 4 Discussion:
5. Discuss difference between our result and previous study and make hypotheses for the observed features
6. Give a brief introduction of RF analysis, a graphical depiction of this model and how it was implemented
7. Clarify the limitations of our study.
Again, thank you very much for your valuable comments. We hope this revised version of manuscript would change your mind to accept our submission. We look forward to hearing from you and would be glad to respond to any further questions and comments.
Best regards,
Tingting Jiang
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
All my concerns in my review have been addressed by this revision. I would like to appreciate the authors' work.
Author Response
Dear Reviewer 1,
Thank you very much for your kind words about our manuscript. We are delighted to hear your appreciation, which encourages us a lot. Thanks to your previous constructive comments and suggestions, we had the opportunity to strengthen our manuscript. In this round of revision, we read our manuscript again in a more careful manner and made a few minor language modifications in the latest version of manuscript. We also found an error in Eq.(3) and modified this mistake. All new changes have been highlighted by using the track changes mode in MS Word, here we detail these new changes:
1. P1 L26: “contains” -> “contained”
2. P2 L41: delete “having”
3. P2 L64: delete “Although”
4. P2 L66: insert “However”
5. P2 L78: “promote” -> “promotes”
6. P3 L115: “during” -> “for the period of”
7. P5 L183: “ from seasonally to monthly, and hourly” -> “from seasonally, monthly to hourly”
8. P5 L233: rewrite the sentence, “AHI and MODIS AOD yield a similar spatial pattern that heavy aerosol loadings are …”
9. P7 L254: “with the reminder falling” - > “ and the rest of retrievals fall”
10. P8 L386-387: rewrite the sentence, “we will still take some time to improve retrieval algorithm to achieve higher quality AHI AOD values”
11. P13 L405: retype the equation:
AOD Truthi,j ~ AHI AODi,j+AEi,j+NDVIi,j+spatial factorsi+temporal factorsj
12. P14 L425: “employed” - > “explored”
We thank you very much for taking your time and effort to review our manuscript again.
Best regards,
Tingting Jiang
Reviewer 4 Report
I've went through the revised version and found it much improved.
I therefore suggest publication as is
Author Response
Dear Reviewer 4,
Thank you very much for your kind words about our manuscript. We are delighted to hear your appreciation, which encourages us a lot. Thanks to your previous constructive comments and suggestions, we had the opportunity to strengthen our manuscript. In this round of revision, we read our manuscript again in a more careful manner and made a few minor language modifications in the latest version of manuscript. We also found an error in Eq.(3) and modified this mistake. All new changes have been highlighted by using the track changes mode in MS Word, here we detail these new changes:
1. P1 L26: “contains” -> “contained”
2. P2 L41: delete “having”
3. P2 L64: delete “Although”
4. P2 L66: insert “However”
5. P2 L78: “promote” -> “promotes”
6. P3 L115: “during” -> “for the period of”
7. P5 L183: “ from seasonally to monthly, and hourly” -> “from seasonally, monthly to hourly”
8. P5 L233: rewrite the sentence, “AHI and MODIS AOD yield a similar spatial pattern that heavy aerosol loadings are …”
9. P7 L254: “with the reminder falling” - > “ and the rest of retrievals fall”
10. P8 L386-387: rewrite the sentence, “we will still take some time to improve retrieval algorithm to achieve higher quality AHI AOD values”
11. P13 L405: retype the equation:
AOD Truthi,j ~ AHI AODi,j+AEi,j+NDVIi,j+spatial factorsi+temporal factorsj
12. P14 L425: “employed” - > “explored”
We thank you very much for taking your time and effort to review our manuscript again.
Best regards,
Tingting Jiang
