Spatial Expansion and Correlation of Urban Agglomeration in the Yellow River Basin Based on Multi-Source Nighttime Light Data
Round 1
Reviewer 1 Report
It is significant for improving the planning and management level of urban agglomeration to uncover the characteristics of urban expansion in urban agglomeration. The paper analyzed the characteristics of urban expansion of five urban agglomerations using gravity center migration model, urban primacy, and gravity models. However, the paper requires a thorough revision. Here are suggestions:
(1) It is suggested that the authors further clarify the background, significance, and gap of urban expansion in the introduction section.
(2) It is recommended to cite relevant literature in the research method section, especially the sources of formula.
(3) Discussion section is too simple. Authors need to focus on the main findings, and reveal drawing conclusions, achievement, limitations and direction for future work.
(4) The citation format of references is not uniform, and some references are incorrectly cited.
Author Response
Dear Reviewer:
Thank you for your comments concerning our manuscript entitled ‘Spatial Expansion and Correlation of Urban Agglomeration in the Yellow River Basin Based on Multi-source Nighttime Light Data’ (Manuscript ID: sustainability-1757753). We have carefully considered every comment, and have tried our best to improve the manuscript. We believe that these comments were all valuable and very helpful for revising and improving our paper, as well as providing significant guidance to our future research.
We are grateful for the time you spent reviewing the paper and providing valuable comments. We hope that the revised manuscript will now be suitable for publication, but we will be happy to work with you to resolve any remaining issues. The main corrections in the paper and the responds to the comments please see the attachment.
Best Wishes!
Sincerely,
Yuanfang Liu
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper integrates DMSP/OLS and NPP/VIIRS night light remote sensing data from 2000 to 2020, and uses GIS spatial analysis to study the spatial expansion and correlation characteristics of five urban agglomerations. I recommend you to check the comments below and carefully revise them.
(1) To justify the paper by clearly indicating the theoretical or methodological contribution of the paper. What is the core innovation of the analysis model?
(2) To expand and rich the literature review by adding more recent and relative researches.
(3) Discussion part is too short, it could be connected to the research results and compared with other studies point by point. Also, suggestions or implications should be summarized. The content of the discussion is important to strengthen the comparative analysis of the results of the article and other studies, and further strengthen the academic contribution and key findings of this article.
(4) Please improve the dpi of Figure 1, the text in the figure is vague.
(5) In Figure 2, please add the name of each agglomeration and each city.
(6) In Figure 3, please point out the specific division of agglomeration.
Author Response
Dear Reviewer:
Thank you for your comments concerning our manuscript entitled ‘Spatial Expansion and Correlation of Urban Agglomeration in the Yellow River Basin Based on Multi-source Nighttime Light Data’ (Manuscript ID: sustainability-1757753). We have carefully considered every comment, and have tried our best to improve the manuscript. We believe that these comments were all valuable and very helpful for revising and improving our paper, as well as providing significant guidance to our future research.
We are grateful for the time you spent reviewing the paper and providing valuable comments. We hope that the revised manuscript will now be suitable for publication, but we will be happy to work with you to resolve any remaining issues. The main corrections in the paper and the responds to the comments please see the attachment.
Best Wishes!
Sincerely,
Yuanfang Liu
Author Response File: Author Response.pdf
Reviewer 3 Report
Dear authors,
some corrections are required in order to improve the quality of the paper. All comments you will find in the attached file.
Best regards
Comments for author File: Comments.pdf
Author Response
Dear Reviewer:
Thank you for your comments concerning our manuscript entitled ‘Spatial Expansion and Correlation of Urban Agglomeration in the Yellow River Basin Based on Multi-source Nighttime Light Data’ (Manuscript ID: sustainability-1757753). We have carefully considered every comment, and have tried our best to improve the manuscript. We believe that these comments were all valuable and very helpful for revising and improving our paper, as well as providing significant guidance to our future research.
We are grateful for the time you spent reviewing the paper and providing valuable comments. We hope that the revised manuscript will now be suitable for publication, but we will be happy to work with you to resolve any remaining issues. The main corrections in the paper and the responds to the comments please see the attachment.
Best Wishes!
Sincerely,
Yuanfang Liu
Author Response File: Author Response.pdf
Reviewer 4 Report
The objective of this manuscript is utilizing nighttime light remote sensing data to examine the expansion of major metropolitan areas in the Yellow River Basin, China. The research questions, methods and results are mostly straightforward to me. Please see my general suggestions and detailed comments below.
General Suggestions:
1. I would suggest replacing all “urban agglomeration” to “metropolitan areas” in the manuscript
2. I think the Introduction section should be re-organized into three or four paragraphs. It can start with an introduction of the general topic (in this case, urban expansion), continue with some of the desired methodology (i.e., nighttime light remote sensing), then identify research gaps, narrow down to your study area, and raise the research questions.
3. I think the authors should provide references to the methods (2), (3) and (4) in Section 2.2.2.
4. In Section Conclusions, the paragraphs should not be organized in a bullet point manner.
Detailed Comments:
1. Lines 10 & 11: Whenever applicable, I would avoid mentioning specific political names in scientific literature, unless it is required by your funding sources (in which case you would have to declare conflict of interest in the end). Something like “The Chinese government proposed/implemented” certain polices/campaigns will be sufficient.
2. Lines 42 & 43: Literature references needed.
3. Line 44: It seems that it is the first time the abbreviation “DMSP” occurred, but I cannot find the full name of it.
4. Figure 1: The study area demonstrates a portion of China. I would suggest including a small insert map locating the study area within China. I would also suggest getting rid of the DEM map and Railway lines, unless the authors have other considerations.
5. Lines 118~126: This part seems can be deleted, for I don’t think it add more introduction to your study area. Besides, I think Table 1 can also be removed. The importance of your study area can be described in a few sentences with several references.
6. Figure 2: I would suggest re-organizing the layout, produce maps similar to those in Fig. 3, with the boundaries between different metro areas highlighted. Besides, I would like to see the specific numbers of the range of each expansion category.
7. Figure 5: Not sure if the maps of 2010 and 2020 were swapped. Seems that there are more connections in 2010 than 2020.
8. Line 387: I think it will better demonstrate your conclusions if you overlay a map of the Hu Huanyong Line with your results. Also, a reference of this line will also be needed.
Author Response
Dear Reviewer:
Thank you for your comments concerning our manuscript entitled ‘Spatial Expansion and Correlation of Urban Agglomeration in the Yellow River Basin Based on Multi-source Nighttime Light Data’ (Manuscript ID: sustainability-1757753). We have carefully considered every comment, and have tried our best to improve the manuscript. We believe that these comments were all valuable and very helpful for revising and improving our paper, as well as providing significant guidance to our future research.
We are grateful for the time you spent reviewing the paper and providing valuable comments. We hope that the revised manuscript will now be suitable for publication, but we will be happy to work with you to resolve any remaining issues. The main corrections in the paper and the responds to the comments please see the attachment.
Best Wishes!
Sincerely,
Yuanfang Liu
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have revised the paper according to reviewer's comments. It is suggested that the authors need to add a compass in Fig2 and Fig3. Also, the legend in Fig2 has some mistake.
Author Response
Dear Reviewer:
Thank you for the second review of our manuscript (Manuscript ID: sustainability-1757753). We are very grateful that you recognize the value of our work, these improvements are based on your previous valuable comments. We have revised Figure 2 and Figure 3 according to your suggestions.
Thank you again for your careful and patient reviewing, which is important to the publication of our manuscript. We appreciate your help and wish you all the best.
Sincerely,
Yuanfang Liu
Reviewer 2 Report
Thanks for authors' careful revision. I do not have other questions.
Author Response
Dear Reviewer:
Thank you for the second review of our manuscript (Manuscript ID: sustainability-1757753). We are very grateful that you recognize the value of our work, these improvements are based on your previous valuable comments. Your careful and patient review is very important to the publication of our manuscript. We appreciate your help and wish you all the best.
Sincerely,
Yuanfang Liu
Reviewer 3 Report
Dear authors,
After all conducted revisions, the manuscript is well organized and the quality of the presented research is upgraded with additional explanations and relevant references.
You will find a few comments in the documents, which require a minor intervention in the manuscript.
Best regards
Comments for author File: Comments.pdf
Author Response
Dear Reviewer:
Thank you for the second review of our manuscript (Manuscript ID: sustainability-1757753). We are very grateful that you recognize the value of our work, these improvements are based on your previous valuable comments. We have revised the manuscript according to your suggestions and responded to your annotations in the PDF file. Please see the attachment.
Thank you again for your careful and patient reviewing, which is important to the publication of our manuscript. We appreciate your help and wish you all the best.
Sincerely,
Yuanfang Liu
Author Response File: Author Response.pdf
Reviewer 4 Report
I think most of my previous comments were addressed. The only exception is that in Line 15, Abstract section, the abbreviation rule still applies, i.e., the full name should be spelled out before abbreviations can be used.
Besides, from the perspective of image interpretation, I would suggest enlarging the maps in Figures 2 & 3. I think the map itself should be the prominent components. Currently the legend and notes take up too much space proportionally.
Author Response
Dear Reviewer:
Thank you for the second review of our manuscript (Manuscript ID: sustainability-1757753). We are very grateful that you recognize the value of our work, these improvements are based on your previous valuable comments. We have added the full names of DMSP/OLS and NPP/VIIRS in the Abstract section and revised Figures 2 and 3 as per your suggestion.
Thank you again for your careful and patient reviewing, which is important to the publication of our manuscript. We appreciate your help and wish you all the best.
Sincerely,
Yuanfang Liu
