A New Framework for Reconstructing Time Series DMSP-OLS Nighttime Light Data Using the Improved Stepwise Calibration (ISC) Method

Round 1

Reviewer 1 Report

The paper “A new framework for reconstructing time series DMSP-OLS nighttime light data using the Improved Stepwise Calibration (ISC) method” deals with the problem of proper calibration of sensor used for the assessment of nighttime light. It is essential to do it with high accuracy because the improper calibration of the sensor can result in incorrect conclusions. The paper is interesting, and nighttime light data can indeed be helpful for the much different research fields. 

 

Detailed comments. 

1.       Main results and conclusions of the quantitative approach in the abstract

2.       L.58-67 It seems that this should be a bulleted list.  

3.       L.113 / L.123 The access date is required or the link should be included in the literature section (with the access date). 

4.       Fig.1 The F10-F18 in this figure are probably particular sensors. It is not clear in this part of the text. The unit for the vertical axis is required. 

5.       The flowchart of the Improved Stepwise Calibration (ISC) method (fig. 2) must be well described. It is not so clear what this method is based on. Moreover, the benefits of using this method should be highlighted more in the text. 

6.       Does formula 2 correct? It seems that something is missed. 

7.       The main drawback of this paper is that the particular sensors are not sufficiently described. What about the basic parameters of each sensor? For instance, the spectral sensitivity or native resolution? It will impact the obtained results and the differences between the sensors and calibration methods.

8.       What was the reference for all the calibration types? 

9.       Why are the correlation factors or R2 not calculated for the functions presented in figure 8? 

10.    Figures 9 and 10 require more detailed quantitative data (minimum and average values). What about the classical box plots? 

11.    Fig. 12 must be improved. The correlation coefficients for the isles are invisible. It seems that showing the value for particular bigger provinces is a good idea. 

12.    L.389-392 This part should be deleted. It is unnecessary.  

13.    What about the weather conditions? Were all data from the given year considered for each presented method/calibration? 

14.    L.471 “This method helps to explain human socio-economic activities.” I guess that the previous method can also do it but using the ISC method provides more excellent reliability. 

 

Author Response

Thank you very much for taking time out of your busy schedule to review this manuscript and express your approval of this article.

In light of the issues you raised, we have made point-by-point changes to the manuscript, details of which are attached.

Thank you again for your approval of this article. 

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper is an interesting study, presenting a new framework for reconstructing time series DMSP-OLS nighttime light data using the Improved Stepwise Calibration (ISC) method, which would be helpful for further research in socio-economic development, urban development, and natural disasters. The study is an original work with extensive literature review and analyses providing new contributions to the body of knowledge in the related fields.

Author Response

Thank you very much for taking time out of your busy schedule to review this manuscript and express your approval of this article.

Given some existing problems, we have improved the abstract, modified the format, supplemented the pictures and replaced the references of the original manuscript to highlight this article's advantages and innovations. Please review it again.

Thank you again for your approval of this article.

Reviewer 3 Report

• Please specify the objectives of the paper.
• What is the added value of research?
• What is the novelty of the paper?
• A comparative analysis between the data obtained by you and those reported in the literature is necessary. Insert a scientific discussion justified by bibliographical references.
• The authors should refine the abstract and the conclusions.

Author Response

Thank you very much for taking time out of your busy schedule to review this manuscript.

In light of the issues you raised, we have made point-by-point changes to the manuscript, details of which are attached.

Thank you again for your suggestion for this article.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The paper has been corrected in line with my comments. Thank you. 

Author Response

Thank you very much for your suggestions and approval of this article.

Reviewer 3 Report

The author should answer briefly and concisely. Along with direct references to the content of the manuscript.

1. Please specify the objectives of the paper.

Authors mentioned: “This paper's objectives are to eliminate the shortcomings of the invariant target region method by using the Improved Stepwise Calibration (ISC) method based on numerical constancy to achieve the calibration and reconstruction of time series DMSP-OLS nighttime light images.”.

Please clarify the specific shortcomings that your works focus on.

2. What is the added value of research?

Authors mentioned: “The Improved Stepwise Calibration (ISC) method proposed in this study is more straightforward to implement, and the reconstructed nighttime light dataset is accurate and reliable.”

The reviewer does not think that the arguments from your results represent an improvement in the straightforwardness of implementation that you mentioned. The results tables are disjointed, lacking a connection between the results and the asserted content that the author provides. The review suggests that the author needs to modify the Results and Discussion sections, with clear explanations from the results table presented with the concluding content.

Please note that the author should not use images and content with political elements or purposes in international scientific publications, as shown in Figure 14. (https://en.wikipedia.org/wiki/Nine-dash_line)

3. What is the novelty of the paper?

Both mentioned novelties of the paper have not been clearly demonstrated due to the lack of connections between the results of the experiment and the conclusions and discussions of the author. (Similar to part 2)

4. A comparative analysis between the data obtained by you and those reported in the literature is necessary. Insert a scientific discussion justified by bibliographical references.

The review accepts the views of the authors. However, it should be tabulated to represent the study's arguments better.

Author Response

Thank you very much for taking time out of your busy schedule to review this manuscript.

In light of the issues you raised, we have made point-by-point changes to the manuscript, details of which are attached.

Thank you again for your suggestion for this article.

Author Response File: Author Response.pdf