Spillover Effects of Urban Expansion on Land Green Use Efficiency: An Empirical Study Based on Multi-Source Remote Sensing Data in China
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis study assessed the impact of urban expansion on land green use efficiency (LGUE) across 269 Chinese cities. The topic is relevant, and I particularly appreciate the attempts made by the authors to integrate multi-source remote sensing data, spatial analysis techniques, and econometric methods. I have only a few minor suggestions. Here are my detailed comments:
(1) In line 72, when the authors review existing literature on the definition of urban expansion, one important way of measuring urban expansion, impervious land surface area, is missing. I suggest that the authors discuss this point further. The following study is for your reference:
Huang, C., & Xu, N. (2022). Quantifying urban expansion from 1985 to 2018 in large cities worldwide. Geocarto International, 37(27), 18356-18371.
(2) Raster data of remote sensing products may not perfectly match the vector data of administrative boundaries. Therefore, the authors need to explain further how they aggregate raster data at the city level (Summation of centroids that fall inside the administrative boundary?).
(3) The authors could consider testing and reporting VIF or correlation coefficients to address the concern of multicollinearity since it seems that the selected control variables may potentially correlate with each other.
(4) A summary of tested variables and descriptive statistics (e.g., number of observations, mean, standard deviation) should be added to the data section.
(5) The authors did not treat carbon emissions as an undesirable output in their LGUE measurement. In the context of global decarbonization, carbon emissions are one of the most important undesirable outputs of urban expansion in China and even the world. As suggested in previous studies, land use and land cover change contributed by urban expansion is one of the leading causes of carbon emissions (Ou et al., 2024). Therefore, this study should explain this in the limitation section. The following study is for your reference:
Ou, Y., Bao, Z., Ng, S. T., Song, W., & Chen, K. (2024). Land-use carbon emissions and built environment characteristics: A city-level quantitative analysis in emerging economies. Land Use Policy, 137, 107019.
Comments on the Quality of English LanguageMinor editing of English language required.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsBrief Summary
The manuscript titled 'Spillover effects of urban expansion on land green use efficiency: An empirical study based on multi-source remote sensing data in China' investigates the impact of urban expansion on land green use efficiency (LGUE) in 269 Chinese cities from 2008 to 2020. It integrates multi-source remote sensing data, GIS spatial analysis, and spatial econometric models to explore the spatiotemporal effects of urban expansion on LGUE.
General Concept Comments
The study addresses the critical issue of balancing urban expansion with sustainable land use, which is highly relevant in rapid urbanization. Using multi-source remote sensing data and spatial econometric models adds novelty and robustness to the research. Integrating various data sources and advanced modeling techniques is vital to this study. Using nighttime light data to measure urban expansion and the super-efficiency EBM-DEA model to evaluate LGUE is useful.
Specific Comments
1. Abstract: The abstract concisely summarizes the study's objectives, methods, and critical findings. However, it could benefit from a brief mention of the policy implications to highlight the practical relevance of the research.
2. Introduction: The introduction effectively sets the stage for the study by discussing the importance of LGUE and the challenges posed by urban expansion. Including a brief review of related studies would strengthen the context further. However, the main goal of the piece must be improved. Figure 1 must be moved from this section.
3. Theoretical Framework: The theoretical framework is well-structured, explaining the social, economic, and environmental effects of urban expansion on LGUE. However, some concepts could be clarified with additional definitions or examples. How do these issues impact human settlements? What is green use efficiency in this context? Figure 2 must be moved from this section.
4. Data and Methods: The section is detailed and transparent, providing a clear understanding of the data sources, variable selection, and modeling techniques. Figures 1 and 2 must be placed here.
5. Results and Discussion: The results are comprehensively presented with appropriate use of figures and tables. The discussion is well-linked to the findings, though it could be enhanced by comparing the results with other relevant studies to contextualize them further. Figure 6 must be improved.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
