Ecological Environment Evaluation Based on Remote Sensing Ecological Index: A Case Study in East China over the Past 20 Years
Round 1
Reviewer 1 Report (Previous Reviewer 2)
Well done, congratulations.
Author Response
We appreciate the positive comments ,and we will do our best to make the article meet the requirements for publication.Thank you and best regards.
Reviewer 2 Report (Previous Reviewer 3)
The paper, after minor second revision according to the attached report, deserve to be published. Best regards
Comments for author File: 
Comments.pdf
Author Response
Thank you for your valuable and thoughtful comments. We will continue our research on remote sensing ecological environment assessment and other aspects, and strengthen the exchange and cooperation with scholars in the same field to promote the RSEI evaluation methods to become more accurate and more widely used. I also hope to have the opportunity to work with you.
Several of the articles you have given are very useful，after a careful reading we think it is very appropriate to quote them and we have made changes in the article (line53-54).
Reviewer 3 Report (Previous Reviewer 4)
Please see the attached.
Comments for author File: Comments.pdf
Author Response
Based on your suggestion, we have made some changes in the article.Please see the attachment.
Thank you and best regards.
Author Response File: Author Response.pdf
Reviewer 4 Report (Previous Reviewer 5)
I served as the reviewer of the original manuscript of this research article. I believe that it can be accepted in its present form.
Author Response
We appreciate the positive comments ,and we will do our best to make the article meet the requirements for publication.
Round 2
Reviewer 3 Report (Previous Reviewer 4)
Thanks to the additional work and explanation with deliberation, the manuscript has been improved.
Most of the captions for the figures can be revised with more information.
Author Response
Thank you for recognizing our work and giving us very meaningful comments. We indeed should change the title of figures and tables in the article.
We reworked the captions of the images and tables in the article, for some combination images, we added sub-captions such as (a) and (b) to each part of the image, and explained them accordingly in the captions.You can find them separately at line114, line154, line231, line239, line277, line305, line322, line329, line335 and line368(Yellow mark in the article).
We hope that all these changes fulfil the requirements to make the manuscript acceptable for publication.
Thank you and best regards.
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
The topic of this paper is interesting,however, from my point of view, there are still many questions to be answered, clarified and improved. The details are as follows.
1. The scientific issues in this paper are not clear.
2. The international perspective of this paper needs to be improved in order to attract more international readers.
3. This paper lacks originality, and there is no obvious innovation in theory or method.
4. Is RSEI spatio-temporal comparable? Because it automatically weights each index based on the load coefficient of the first principal component, and the load coefficient of each component of the principal component transformation changes according to the input data, that is, the weight of each index changes according to the data at different times and places. Will this make the RSEI incomparable in time and space?
5. The remote sensing image can only reflect the surface state at the moment of imaging, while the regional ecological environment is a normal state. The rationality of using the instantaneous data to represent the normal data for multi-stage comparison is questionable. For a simple example, if there is a heavy rain just a few hours before imaging, the humidity will be greatly increased, and this occasional event will lead to doubts about the authenticity of the results.
6. The Discussion is very weak, lacking in-depth analysis of the results, explanation of the reasons and policy recommendations, and no comparison with other authors’ results, and no response to scientific questions, which should have been clearly put forward in the Introduction.
Reviewer 2 Report
Review of the manuscript “Ecological environment evaluation based on RSEI: A case study in East China over the past 20 years”
The manuscript showed a case study located in East China using RSEI and GEE for spatial and temporal changes in ecological environment quality detection. The dataset includes land cover/land use products, high-resolution images, MODIS, etc.
The manuscript fits very well to the scope of sustainability and it has a significant contribution in terms of using a different dataset. Overall, in my opinion, this manuscript is acceptable for publication in this high-standard journal.
Comments
Data: - Need more details
1) GLC - What are the Land cover classes used. Please describe it.
2) Image data, high-resolution and MODIS image; explain in detail the purposes of each one?
3) RSEI is a function of (Greenness, Wetness, Heat, Dryness), explain this function in detail and explain how did you combine it with different spatial resolutions, need more detail.
4) Google Earth Engine, what is the purpose of GEE with RSEI, it is not clear?
Methods: you need to add this section
5) It is missing after describing the data the Methods section. Suggestion: add the methodological steps, you could also use a figure to show a methodological flowchart and explain it in detail.
6) Explain the RSEI threshold criteria used
7) Principal Components Analysis (PCA), how did you set up it, need more details.
8) There are different spatial and temporal resolution data for RSEI evaluation. How could you validate your results? Alternatively, what are the limitations of your methods? Maybe you could improve the conclusions of the limitation in more detail regarding validation and accuracy.
9) It is missing in the discussion similar case studies to support your findings, just add other relevant papers.
10) Once, you detected the RSEI maybe you could mention that the next step that could be looking closely at this particular site, perhaps to understand what is going on. Another issue is the anthropogenic factors that were not explored well in this approach. Something like this will enhance the final “take home message” of your very nice manuscript and just give clues to support even more your limitations and future works.
Reviewer 3 Report
Please see attachment
Comments for author File: Comments.pdf
Reviewer 4 Report
Please see the attached.
Comments for author File: Comments.pdf
Reviewer 5 Report
Overall comments
There are some inconsistencies in the numbering and punctuation. But these are minor issues that can be quickly revised by the authors.
Abstract
Line 17
The service of Google may not cover China. For example, the products of Google such as Google Maps may not be available in China. But there are other service providers such as Baidu Maps. If the methods proposed in this paper, maybe alternative methods have to be put forth.
Line 25
The meaning of the term “high point” should be explained
Line 29
Reading this line, the readers may wonder the cause of the rise in the vegetation coverage. Perhaps the authors can use a few terms to express the possible reason(s)
Introduction
Line 49
Remote sensing was mentioned in this line. Perhaps the authors can provide an overview of remote sensing platforms
Line 60
Only one reference was provided for this method. It is believed that the authors can provide references to more studies.
Line 69
Again, the readers may wonder whether Google Earth Engine is fully accessible if some researchers would like to obtain cartographic information from China. Clarifications can be provided.
Line 75
It is suggested that the authors should provide some numbers related to the economic development of China. For instance, the economic pillars of the study area can be mentioned.
Line 81
The phrase “Long-term” is used here. Perhaps the authors can state the exact number of years involved.
Materials and Methods
Line 88
It is believed that the first sentence is tautological. Perhaps the authors can provide a map of East China to enrich this section.
Line 94
There are a lot of names of Chinese cities and provinces. If a reader knows the Chinese language, he or she may still even have problem comprehending the name of the places. Would it be possible to provide the literal English translation of the places which are frequently mentioned in this manuscript? This can enhance the readability to a larger extent.
Line 96
What is the climate classification of the study area? Perhaps the Koppen-Geiger climate classification can be referred to.
Line 100 & 101
A space should be inserted between the numbers and the units.
Line 102
For Figure 1, the level of jurisdiction, e.g. city, province, county, can be provided
Line 106
For readers from backgrounds other than GIS studies or geography, they may be new to GLC_FCS30. The authors should provide some background information.
Line 133
What software(s) was used in the data analysis?
Line 149
The indicators were said to be “regulated”. Do the authors implied that data transformation was applied on the data? Clarification should be provided
Line 154
There is no need to provide two spellings of the term petabyte.
Results
Line 169
This is a type writing question. Why is the number “2” of Figure 2 underlined?
Line 171
The word “low” is used there. But in this section, it is believed that the authors should provide some quantitative findings supporting the use of this word.
Line 180
Different cities showed different trends. Although the overall pattern of “first increasing, then decreasing” was observed, the magnitude could be different. For some locations, the subsequent increase in the mean value of RSEI failed to compensate for the loss made earlier on. Certification should be provided.
Lines 188 to 207
The term “spatial heterogeneity” was spotted here. But for spatial patterns, it would be more appropriate to use a software to analyse the findings
Line 236 to 237
What is ecological civilization? The authors should clarify
Discussion
Line 268 to 296
Many terms are heavily used. The authors should provide the meaning of the abbreviations
Comments for author File: 
Comments.docx
