Assessment of Seven Atmospheric Correction Processors for the Sentinel-2 Multi-Spectral Imager over Lakes in Qinghai Province

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript titled “Assessment of Seven Atmospheric Correction Processors for the Sentinel-2 Multi-Spectral Imager over Lakes in Qinghai Province” compared the applicability of seven publicly available atmospheric correction processors for the Sentinel-2 Multi-Spectral Imager over Lakes in Qinghai Province, which is significant to water quality monitoring based on the Sentinel-2 Multi-Spectral Imager. However, there are some questions to be discussed:

1. There are two paragraphs in this manuscript entitled "Image data", “2.2.1. Image data” and” 2.2.2. Image data”, the author should confirm the correct expression.

2. The field water spectrum measurement tests were conducted in this paper, it is suggested to further clarify the method of spectral measurement and the instruments used. How to measure the water color index and turbidity at the 49 sampling points?

 3. In Figure 3, is the reflectance data for typical lakes and reservoirs the average of the sampling points for each lake (or reservoir)?

4. The sampling and analysis of typical lakes and reservoirs in the study area in this paper were all conducted in July and August. Then, what is the applicable scope of the atmospheric correction method and adaptability evaluation involved in this paper?

Comments on the Quality of English Language

The manuscript titled “Assessment of Seven Atmospheric Correction Processors for the Sentinel-2 Multi-Spectral Imager over Lakes in Qinghai Province” compared the applicability of seven publicly available atmospheric correction processors for the Sentinel-2 Multi-Spectral Imager over Lakes in Qinghai Province, which is significant to water quality monitoring based on the Sentinel-2 Multi-Spectral Imager. However, there are some questions to be discussed:

1. There are two paragraphs in this manuscript entitled "Image data", “2.2.1. Image data” and” 2.2.2. Image data”, the author should confirm the correct expression.

2. The field water spectrum measurement tests were conducted in this paper, it is suggested to further clarify the method of spectral measurement and the instruments used. How to measure the water color index and turbidity at the 49 sampling points?

 3. In Figure 3, is the reflectance data for typical lakes and reservoirs the average of the sampling points for each lake (or reservoir)?

4. The sampling and analysis of typical lakes and reservoirs in the study area in this paper were all conducted in July and August. Then, what is the applicable scope of the atmospheric correction method and adaptability evaluation involved in this paper?

Author Response

Dear reviewer，

We feel great thanks for your professional review work on our manuscript. As you are concerned, there are several problems that need to be addressed. According to your nice suggestions, we have made corrections to our previous manuscript.

Once again, thank you very much for your comments and suggestions.

Kind regards,

Yours sincerely，

Wenxin Li

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript presents a study on the performance of different atmospheric correction processors for the Sentinel-2 Multispectral Imager. The adopted methodology is appropriate and the experiments were thorough. Other than language, which has some issues and would benefit from a careful revision, in my opinion the only part of the manuscript that could be improved is the discussion. In particular, it would be useful to include some comments on the generality of the results obtained, that is, what should be expected if those same atmospheric correction processors were applied to lakes located in regions with different characteristics. Although the authors pointed out that the Qinghai Province has some variations, the variability of the problem when the whole world is considered is certainly much higher. Although no experiments were carried out for those other conditions, the authors should have gathered enough experience and insights to at least speculate about this aspect.

Comments on the Quality of English Language

Language has some problems (mostly minor) that can be easily addressed and corrected.

Author Response

Dear reviewer，

Thank you for your letter and for the comments concerning our manuscript entitled “Assessment of Seven Atmospheric Correction Processors for the Sentinel-2 Multi-Spectral Imager over Lakes in Qinghai Province” (ID: remotesensing-2678769).These comments are all valuable and very helpful for revising and improving our manuscript, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portion are marked in a different color in the paper.

We appreciate for your warm work earnestly, and hope the correction will meet with approval. Once again, thank you very much for your comments and suggestions.

 

Kind regards,

Yours sincerely，

Wenxin Li

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

Dear authors,

the manuscript titled "Assessment of Seven Atmospheric Correction Processors for the Sentinel-2 Multi-Spectral Imager over Lakes in Qinghai Province" provides an in-depth investigation into the performance of seven different atmospheric correction processors used with the Sentinel-2 Multi-Spectral Imager (MSI) for monitoring water bodies in Qinghai Province, China. The authors compare the effectiveness of these processors in different types of lakes and provide valuable insights into their applicability. The manuscript offers a comprehensive evaluation of the performance of atmospheric correction processors applied to remote sensing of water bodies using Sentinel-2 MSI. It is well-structured and based on rigorous methodology, ensuring reliable results. Here are some notable points:

The methodology is well-defined, and the use of in-situ data and Sentinel-3 OLCI Level-2 Water Full Resolution (L2-WFR) products for classification and evaluation is sound. The selection of seven commonly used atmospheric correction processors allows for a thorough comparison.

The results section is informative and provides clear insights into the performance of the different processors in various lake types. The classification of lakes into three categories (Class I, II, and III) based on spectral characteristics is a valuable contribution to the field. The graphical representations are particularly helpful in understanding the findings.

The discussion section effectively delves into the implications of the results. It highlights the strengths and weaknesses of each processor for different water types, offering valuable guidance for future research and practical applications. The discussion about the central wavelengths of the sensors and their impact on results adds depth to the analysis.

The conclusions are well-structured and summarise the key findings succinctly. The manuscript successfully demonstrates the varying performance of the processors based on water body types, providing actionable insights for users of remote sensing data in the region.

The manuscript is well-written and clear. The use of figures, tables, and equations enhances the presentation and understanding of the research. There are a few issues that should be addressed. In particular:

1. Use passive voice throughout the whole manuscript.

2. There are some mistakes in terms of cross-references (e.g. P3L132 - " as shown in Figure 1Figure and Table 1.". You should correct them

3. Enlarge all the maps and images. Some of them are not readable (e.g. Figure 5, 11 etc.).

4. Since you are using a lot of abbreviations, you should provide a Table of all of them.

 

 

Comments on the Quality of English Language

Minor editing of the English language is required

Author Response

Dear Reviewer，

We thank you for the time and effort that they have put into reviewing the previous version of the manuscript. These suggestions have enabled us to improve our work. 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. We would like also to thank you for allowing us to resubmit a revised copy of the manuscript.

We appreciate for your warm work earnestly, and hope the correction will meet with approval. Once again, thank you very much for your comments and suggestions.

 

Kind regards,

Yours sincerely，

Wenxin Li

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The revised version of the paper has met the publication requirements and is approved for publication.

Comments on the Quality of English Language

The revised version of the paper has met the publication requirements and is approved for publication.