Simulation-Based Optimization of the Urban Thermal Environment through Local Climate Zones Reorganization in Changsha City, China with the FLUS Model
Round 1
Reviewer 1 Report
Overview and General Judgment.
The MS made an attempt to optimize the thermal urban environment by suggesting a spatial reorganization (spatial layout) of the 3d LULC in the central Chinese city of Changsha. For that, the authors used Landsat 8 imagery on three dates (2010, 2015, and 2020) to extract LCZs, while the LST retrieval was achieved based on MODIS imagery. The spatial layout optimization of LULC was implemented using the future land use simulation (FLUS) model. I think the work is original and has a really novel idea with workable significant values pertaining to urban planning and design. The paper structure is semi-complete, and the analytical procedure is clear. However, the provided major comments and issues must be fixed and fulfilled first, particularly those related to the paper citation, methodology, and discussion.
General recommendations.
1. The MS topic is strongly relevant to the journal's aims and scope.
2. LCZs is a trendy topic in recent urban research.
3. The MS structure is correct and academically acknowledged. A single modification is required: restrict section 2 only on "study area" and move data process into section 3 "materials and methods".
4. The English language is largely understandable and was provided at a reasonable academic level of writing. However, further improvements are required for a much higher academic level.
5. The usage of tenses is somehow defective. You usually use present simple in the "Abstract", "data sources", "Results", "Discussion", and "Conclusion". Revise these sections and provide your own analysis, results, and discussion using the past tense.
6. Some vocabularies were intensively used, making poor language repetition. For example, the word livability used 12 times across the MS. Using alternative synonyms is encouraged.
7. When writing, be concise and direct as possible.
8. The methodology is up to date, clear, and well-organized. Its narrative flow wasn't smooth enough. Conciseness A critical defection was observed which will be stated later.
9. Formulas need to be numbered.
10. Tables and charts are sufficient and look in a reasonable appearance. Some enhancements should be conducted. Appearance and artistic aspects can be improved.
11. In-text citation and reference list comply with the journal author guide. An exception was observed in p 6, where invalid citation style exists.
12. The references are recent and diverse but somehow short (35 references).
13. Referencing is required in many places to cite significant details. For example, the 2nd paragraph in the introduction provided significant details without any citation. In addition, the last paragraph in p 2, the last paragraph in p 3, study area subsection.
14. Abbreviations shouldn't appear before the relevant full words. For example, the abbreviation WUDAPT was written in p. 7 before the full words.
15. Some acronyms were defined many times throughout the MS, such as "land surface temperature" in pp 1;6, "local climate zones" in pp 1; 3, and "land use / land cover" in pp 1; 1.
16. Don't use full words after defining their acronyms. For example, although the abbreviation of "Land surface temperature" was defined twice, the full words were used 13 times throughout the MS. The same comment is also valid for "local climate zones".
17. Use a standard nomenclature throughout the study. For example, you used different term forms to indicate the same meaning: land covers/uses and land uses/covers.
18. Abbreviate "local climate zones" as LCZs not LCZ. Modify across the MS.
19. Regarding the terminology, you frequently used "LCZ classes". In fact, the word classed is redundant with the word zones "or the letter Z in LCZ". Use "LCZs" is more correct than "LCZ classes". Also, Use "Land surface temperature" instead of "surface temperature" which means air temperature not ground temperature. In addition, some odd words were used to indicate well-established scientific terms, such as daily high temperature (correction: daily maximum temperature), daily low temperature (correction: daily minimum temperature) the maximum daytime temperature (correction: the absolute maximum temperature).
Major comments:
20. As the FLUS model is a key method, it is preferable to appear in the title.
21. I strongly suggest the following Title "Simulation-based Optimization of the Urban Thermal Environment through Local Climate Zones reorganization in Changsha City, China ".
22. In the "Introduction", the criticism of previous literature by the authors was frequently inaccurate. For example, the authors reported that "Almost no research considers the relationship between land structure and heat environment from a three-dimensional perspective with buildings and vegetation’s heights taken into consideration for spatial land-pattern optimization". In fact, this judgement is wrong, simply because the current paper not the first to treat LCZs as a 3D classes urban segmentation. Unbelievable !!! this paragraph (the last in p 2) has a full absence of citation for the criticized papers.
23. The introduction section should end with a final paragraph that lists the MS objectives, the datasets, and the methods. Move Table 1 into the methodology section. The narrative flow and the logical progression in the section need a complete review.
24. In-text citation is a serious weak point in the MS. Critical parts and crucial authors' judgements/criticisms in the introduction section need to be cited. The subsection "study area" also in a critical need to be cited.
25. You should use the same nomenclature to indicate the imagery. In LCZs, you here used the SATTELITE name (Landsat 8) to indicate your images. However, in LST, you used the SENSOR name (MODIS). So, you should use a complex name (satellite + sensor) indicating the image sources, i.e., Landsat 8 OLI/TIRS and Terra MODIS or Aqua MODIS.
26. Regarding the LCZs, assessment of the output (such as Kappa coefficient) is critical, and the evaluation measures are a key output along with the LCZs map. However, the paper completely misses this evaluation. It should be attached to the subsection "3.1. LCZ Classification".
27. A serious methodological defection was detected, due to which the whole MS processing and analysis may be repeated from scratch. The authors used Landsat 8 imagery on three dates (2010, 2015, and 2020) to extract LCZs, while the LST retrieval was achieved based on MODIS imagery. Since the spatial resolutions of Landsat 8 and MODIS data are 30 m and 1 km, respectively, the authors resampled the data to the same resolution of 1 km. in fact, I have two critical issues here. Firstly, the authors shouldn't use different imagery for retrieving LCZs and LST because both parameters can be extracted from one source imagery with a higher spatial resolution, i.e., 30 m in Landsat 8. Secondly, supposing the authors already utilized Landsat 8 and MODIS, the authors should not have made a resample to the coarse spatial resolution, i.e., 1 km, but to the finer spatial resolution of 30 m. So, the whole processing and analysis MUST be redone from scratch through depending just on Landsat 8 optical bands (OLI) and thermal bands (TIRS).
28. The authors used MODIS LST in the study. There is not any indication throughout the paper if the LST values represent the daytime or nighttime. In fact, the dependence of the paper on only day or night LST is a critical flaw because it is scientifically recognized that realizing the whole picture of LCZs effect on LST can be just achieved by investigating its thermal roles in both the daytime and nighttime. So, the perspective and findings of the paper is largely incomplete.
29. The authors provided a conversion cost matrix to express the LULC The difficulty of converting different LCZ types to others in the already-erected cities. I think the paper would be more valuable if its scope is changed (or broadened) to apply on the cities planned to be established in the future.
30. The "Discussion" section is so terse (1.5 p) and poor relative to the MS full length (27 p) and the "Results" section (9.5 p). It should be rewritten and provided in a largely enriched version. I suggest making a fusion between the results and the discussion in a single section.
Minor/specific comments:
Title
31. Local Climate Zone <> Local Climate Zones.
32. Land surface temperature <> thermal environment.
33. In Changsha <> In Changsha City, China.
Abstract section.
34. heat environment <> thermal environment.
35. Existing studies optimize urban landscapes <> Existing studies on optimizing urban landscapes.
36. increases by 5.98%, <> increased by 5.98%.
37. decreases by 20 7.64% <> decreased by 20 7.64%.
38. will be newly built <> was suggested to be newly built.
39. (LCZ9) will be developed <> (LCZ9) should be developed.
40. achieve a -5.2℃ <> achieved a -5.2℃.
Keywords section.
41. For efficient indexing, don't use redundant terms with the MS "Title". Remove the keywords "Local climate zone".
42. The keyword "surface temperature" has a misuse. In fact, surface temperature means "near-ground air temperature" not LST. It can be replaced with "Land surface temperature".
43. Suggested keywords may be "WUDAPT ", "three-dimension landscape", "Urbanization", "Sustainable development".
Introduction section.
44. is the crucial to <> is crucial to.
45. Natural vegetation <> green areas (or vegetated lands).
46. [9; 9] <> [9]
47. urban land covers/uses <> urban LULC.
48. all these studies above <> the above-mentioned studies.
49. such an objective <> such objective.
50. with same ground cover structure <> with the same ground cover structure.
51. , and 17 types are <> . 17 types are.
52. Recent researches show <> Recent researches believe.
53. [2222; 23] <> [22; 23]
54. a more targeted way <> a more efficient way.
55. Move Table 1 and the relevant details describing each LCZs into the methodology section (pp 3-5).
Study area and data process.
56. Study area and data process <> Study area.
57. Move subsection "2.2. Data source and process" to the "material and methods" section. The name can be changed to "Datasets description and preprocessing".
58. the urban population increasing <> an urban population increasing.
59. the building area increasing <> a building area increasing.
60. about 56.04% <> by about 56.04%.
61. about 85.26% <> by about 85.26%.
62. (Statistical Yearbook of Urban Construction www.mohurd.gov.cn, Ministry of Housing 143 and Construction). Change to IEEE in-text citation.
63. What did you mean by "The gathering of population"?
64. summer last for <> the summer season lasts for.
65. Summer last for about 4 months of the year. This is general knowledge that doesn't require a source or even to be written.
66. daily high temperature <> daily maximum temperature.
67. daily low temperature <> daily minimum temperature.
68. the maximum daytime temperature <> the absolute maximum temperature.
69. in the hot summer <> in the summer.
70. The temperature environment of Changsha needs improvement <> The thermal environment of Changsha is in critical need to be mitigated.
71. Figure 1. <> Fig. 1.
72. Figure 1 is not cited in the text.
73. Figure 1 needs some annotation text to be readable, understandable, and self-explanatory. Also, another map frame should be added to illustrate the borders of the city and its internal site configuration and urban structure (the city interior).
74. What did you mean by "socio-economic natural data"? I think you mean socio-economic and natural data. If so, use "climate and socioeconomic datasets".
75. The remote sensing data use Landsat 8 images <> The remote sensing data use Landsat 8 images <> The remote sensing data includes Landsat 8 images.
76. we use ArcGIS10.2 <> we used ArcGIS10.2 software.
77. are converted <> were converted.
78. In table 2, attach the URL of datasets obtained from websites.
79. In table 2, Modis <> Terra MODIS (or Aqua MODIS).
80. In table 2, Landsat 8 <> Landsat 8 OLI.
3. Materials and Methods
81. Start the section with a new subsection "Datasets description and preprocessing".
82. Fig 2 Needs intensive revision or remove it.
Results
83. Don't use 2-level subsections (4.1, 4.1.1). Reorganize the section to include only a single level of subsection (4.1, 4.2, etc.).
84. So important: use the past tense to rewrite your own analysis, results, and discussion. Sor example, In this paper, we first use <> In this paper, we first used.
85. is cluster of <> is a cluster of.
86. In Table 5, change the column "land use type" to "land cover types".
87. In Table 6, change the word "ratio" to "percentage".
88. Fig 4 is fully unclear.
89. The figures and tables should be self-explanatory. The letters W, M, and G in Table 7 have no relevant meanings. Replace the letters with meaningful words or explain the letters' meanings in the table caption.
90. Fig 6 caption is not meaningful.
Discussion
91. Start the section with introductory sentences about the key results.
92. The section is so terse (1.5 p) and poor relative to the MS full length (27 p) and the results section (9.5 p). It should be rewritten and provided in a largely enriched version. I suggest making a fusion between the results and the discussion in a single section.
Conclusion
93. Start the section with an introductory statement about the main objective of the MS.
94. State actionable recommendations, the method limitations, future studies, suggested improvements, etc.
1. The English language is largely understandable and was provided at a reasonable academic level of writing. However, further improvements are required for a much higher academic level.
2. The usage of tenses is somehow defective. You usually use present simple in the "Abstract", "data sources", "Results", "Discussion", and "Conclusion". Revise these sections and provide your own analysis, results, and discussion using the past tense.
3. Some vocabularies were intensively used, making poor language repetition. For example, the word livability is used 12 times across the MS. Using alternative synonyms is encouraged.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The study investigates the optimization of urban surface temperature and proposes insights for enhancing urban livability in the city of Changsha, China. The manuscript shows a robust methodology and supported results derived from comprehensive datasets. The primary focus of the research lies in Local Climate Zone (LCZ) modeling and the utilization of genetic algorithms (GA) to simulate the Future Land Use Simulation Model (FLUS).
To improve the manuscript's content, the following suggestions can be implemented. The abstract can be revised to succinctly summarize key findings. Ensure that the introduction contains research question(s). Figure 2 (page 8) can be enhanced for better visualization by including essential details like study duration, data sources, and software tools used.
Moreover, adding a section on practical implications will discuss how the findings can be applied in urban planning and design. Additionally, a brief section on future research can suggest potential areas for further investigation.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 3 Report
Initially, I would like to congratulate the authors for the excellent work submitted to the journal. The importance of discussing the discussed topic is of unique relevance to environmental science as a whole. However, the work is lacking in some aspects, which end up weakening it too much.
1) Line 98 – Review the citation form of the bibliographic reference according to MDPI rules.
2) Between lines 73 and 89, the word “objectives” appears six times. It would be interesting to rewrite the ideas in this part in order to make the writing of the article more scientific.
3) Is the research objective between lines 168-169? If yes, this should be in the introduction of the paper, together well connected to the research problem, which is a question, and not clear in the research. This structural modification of the research is essential for the approval of the article, rewriting the introduction with these elements (research problem and objectives).
4) Line 190 – do not use first person plural in scientific writing.
5) Between lines 280 and 296, the word “objectives” appears five more times. Deeply review this form of writing.
6) Figures 04 and 05 are ineligible. Review quality and size so the reader can see the results.
7) Lines 614 – 616: Would this be a specific research objective? If so, it should be in the intro.
8) Figure 06 – What is it for? What do you want to show with it? What does it reveal about results? This must be written in the text. An item in an article is never closed with a figure, much less the overlapping of a table and figure in the sequence.
The research and manipulation of the data is very well done. Congratulations to the authors for having worked so well with LCZ and LST data. The suggestions left here are to improve the presentation of the manuscript.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 4 Report
General
Overuse use of acronyms detracts from the readability of a paper. Reduce the use of acronyms, and avoid them at least in table headings and figure captions.
Abstract
Reduce the use of acronyms in an abstract or better avoid them altogether. An abstract should provide an overview of the work without reading the full text.
Line 23ff. The authors claim ‘The optimization results achieve a -5.2oC reduction of average LST in Changsha, …’. This is a very strong statement. I found no evidence in the paper to support such a claim. It is even unclear what baseline the figure -5.2oC refers to. I see only two options here, either add a detailed justification or remove the statement.
Introduction
Table 1: Assuming the information is from another source, the source should be indicated in the table heading.
Data Sources
Table 2
Quality and properties of the input data are one of the most decisive factors for the results of an analysis. More details need to be provided.
First, references to exact data sources are needed, of course.
Second, the data processing to fit all data into a 1km x 1 km raster should be discussed in some more detail. In what framework were GDP data available? Figure 4(e) and Table 7, row ‘G’ both suggest that GDP data were available only for administrative units. Which, by the way, is common for statistical data in most countries. What are the implications of such a very different geospatial reference system for the credibility of the results?
Third, the relatively coarse resolution of 1km x 1km results in a very small number of cells for some of the most critical local climate zones LCZ, such as high-rise buildings LCZ1, LCZ2, LCZ3, and heavy industry LCZ10. For instance, from Table 6, the number of cells for LCZ1 can be calculated from area ratio 0.04 percent of the total number of 12,421 cells (line 221), 12,421 x 0.0004 = 5 cells. Any statistical analysis of such small numbers can not have much significance.
Considering the coarse resolution of most available input data and the size of the study area, the 1km x 1km resolution seems acceptable. Nevertheless, the limitations should be made clear throughout the paper to avoid over-interpretation of the results.
Methods
Supervised classification is a standard method for classifying remote sensing data. The authors performed some interactive post-processing of the automatic classification results. They claim ‘Resample the inconsistent training area and repeat the last step. Until Consistent with the actual situation.’ (line 209ff). Typically, one would assess the quality of the results obtained by checking them against a number of ground truth values. As a minimum, an informed estimate should be given as to the accuracy achieved in the final classification result.
Establishing optimization objective and constraints (line 174f)
To me, the differentiation between ‘objective’ and ‘constraints’ remains unclear. In line 293 ff the authors define their optimization objective being ‘to control the land surface temperature’, which seems to be another constraint rather than an optimization objective. So what is the target function of the optimization? Is it hidden somewhere behind being ‘consistent with the urban sustainable development planning requirements’? (line 295f), ‘Driving factors’ (Figure 2)? If improving land surface temperature would be an objective, it certainly would not lead to an increase in built up areas. The results presented in Table 8 point in the same direction. Increasing built up areas at the expense of the natural environment can most likely only be due to a target function other than optimizing land surface temperature. Please explain how you defined the development target functions.
Table 7. What is the meaning of the columns W, M, G? Column W seems to show correlation factors in the standard range (-1,+1). But how should the columns M and G be interpreted?
Conclusions
The authors mention some limitations of the paper, essentially related to further refinement of their algorithmic solution. I suggest that the prospect of improvements should be shifted to the proper application of the methods used so far. As mentioned by the authors, the adaptation of the used cost conversion matrix to the local situation could be promising. Another issue of concern is the properties of the input data used, which should be considered more carefully.
Minor issues
Line 485: ‘population 32,902’, what does that mean, population per cell?
Line 503: 375.509 million yuan, 3.42 million yuan, values per what unit? Population, area, …?
What does ‘population carrying’ mean? Something like the maximum number of population that a specific area can hold? Or something else?
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The authors adequately responded to the proposed revisions. The current version is highly improved. The logical structure and narrative flows are smooth. The methodology is clear and valid. The conclusions were born out of the results in a correct way. The overall rating of the MS is satisfactory enough to recommend publishing the MS as is.
Reviewer 2 Report
The manuscript is much improved. Therefore, I recommend it for publication
Reviewer 3 Report
The authors answered the answers and doubts about some points of the manuscript. Congratulations on the search. I recommend publishing.
Reviewer 4 Report
The authors invested visible work to improve the paper. Their efforts were partially successful. In some cases, whether due to misunderstandings or other reasons, there was only little if any improvement.
Generally speaking the reviewers' comments should results in improvements of the manuscript rather than lengthy explanations to the reviewer in the cover letter.
Overall I consider the improvements are sufficient for the paper to be published.
