Quantifying and Comparing the Cooling Effects of Three Different Morphologies of Urban Parks in Chengdu
Round 1
Reviewer 1 Report
The article meets the conditions to be published in the Land journal
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Reviewer 2 Report
This is an interesting and relevant study
Better to use hectares than hectometers
Data is plural – so data ‘were’ e.g., line 150
Line 177 – explain why 30m pixels were selected
Line 201 – avoid ‘the paper will’ – it has already done this so say so ‘the research measured and compared’
Line 214 -upper case ‘t’
Line 227 – re-phrase to improve the English language
Line 238 – ditto –‘relatively lacking in greenspace’
Line 240 - 241 - explain and expand on this
General – don’t ned two decimal points for your data – it is meaningless. One point is fine.
Figure 4 – provide a key for the axis labels
Figure 5 – ditto
Figure 6 – ditto
I have some concerns about the lack of a wider global liteature - so please do address this - there is plenty on urban heat islands and for instance, on urban trees lowering summer peak temperatures - so please inlcude this as wider context for your study. Check the Britisih, European and American literature.
What are your thoughts on the landscapes in which your parks sit - the urban forest and the garden areas? Or are the parks the only significant grenspaces? Do tell us. What about roadside trees?
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Reviewer 3 Report
This study examines the cooling effect of the park on the surrounding urban area, but should not be published as an academic paper because the methods used are clearly inappropriate, as shown below.
In this paper, the cooling effect of an urban park is measured by its external ambient ground surface temperature (LST). The cooling effect of a park is a phenomenon whereby the cold air generated in a park flows out into the surrounding urban area, resulting in a decrease in air temperature in the surrounding urban area, which cannot be assessed using ground and roof surface temperatures. Therefore, the approach of this study, which uses surface temperatures for evaluation, is inappropriate. In addition, the cold air produced in the park is relatively heavy and therefore flows out near the ground surface. Thus, the run-off conditions differ depending on the geometry of the buildings and other structures in the surrounding urban area. Therefore, the approach used in this study, evaluating the runoff according to the distance from the park, is inappropriate. In addition, the cubic polynomial approximation of equation (4) keeps increasing with distance in the region of the without cooling effect. Therefore, the approach of this study using a cubic polynomial, which cannot be physically explained, is inappropriate.
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Reviewer 4 Report
There is no serious problem, and the article will be acceptable after revision.
[Main comments]
The study is based on satellite-measured radiance land surface temperature (LST) for a specific summer day. It is recognized that the LST can deviate from air temperature by a few degrees Celsius or more (e.g., doi:10.1126/sciadv.abb9569), and are not necessarily the best measure of the urban thermal environment. Additionally, the LST may vary from day to day depending on the surface conditions such as wetness, because of which the generality of this study must be reserved in this respect. These should be stated as the limitation of this study.
The analysis is based on the classification of "round" parks and "strip" parks. It is recommended to give the criterion of the classification, in as quantitative way as possible.
[Other comments]
@ Line 18 "the cooling efficiency is 0.6923" --- I cannot find this value in the main text.
@ Line 20 "30hm2"--- 30ha? The same applies to Lines 21, 465, and 466.
@ Line 20 "When the area and perimeter thresholds of urban parks" --- It will be easier to understand the sentence without the word "thresholds".
@ Line 22 "when the shape index of the" --- It may be better to add an explanation of "shape index", which indicates the degree of complexity of the park boundary.
@ Line 40 "patch morphology" --- Please explain the concept of "patch" in this study. Is it identical to a park, or is a park composed of more than one patch? I cannot understand why only some variables have a suffix i in Table 1.
@ Line 56 "urban park perimeter was negatively correlated with surface temperature" --- This sentence is ambiguous. Do you mean "the length of urban park perimeter was negatively correlated with surface temperature"? Temperature of what area do you mean (outside or inside the park)?
@ Line 86 "due to the characteristics of nonlinearity, there are thresholds for the cooling effect of urban parks" --- This sentence is hard to understand. It will be better to add an explanation such as that written in Lines 418-423.
@ Line 142 "The urban park AOI data" --- Please explain the abbreviation "AOI".
@ Line 146 "(Table 2)" --- Do you mean Table 2 in Sect. 3.3? If so, please write "as shown later in Table 2 in 3.3" or something so that readers don't have to search the table.
@ Line 149 "August 11, 2019" --- Isn't it possible to write the observation time of the day?
@ Line 214 "the larger the PCI, the greater the cooling capacity of the park's external areas, regardless of park size and shape." --- This sentence is hard to understand, although it makes sense if the word "external" is replaced by "internal".
@ In the figure caption of Fig.3, the explanations for b and c appear to be reversed.
@ Line 260 "After excluding the ineligible urban parks --- (Figure 5)." --- It will be better to write the number of parks selected for the analysis (67?).
@ Line 268 "Figure X" --- Which figure do you mean?
@ Line 349 "by about 806m" --- Please check if this is correct.
@ Line 387 "which may be due to the generally larger shape index of round parks." --- As an alternative interpretation, it will be possible to consider that a strip park has a longer perimeter for its area than a round park, because of which cool air is dispersed over a larger area with lower cooling efficiency. However, I wound not require revision on this matter.
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Reviewer 5 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.
Line 150: review citation of web pages according to journal guidelines.
Figure 3a: this figure is very good, please enlarge it, make it more prominent, one page only for it. It is the core of the work.
Very interesting research, congratulations to the authors.
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Round 2
Reviewer 3 Report
The authors considered my previous points, but did not revise the manuscript accordingly, only insisting on the validity of their own method. Therefore, unfortunately, I cannot change my previous rejection decision this time.
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Reviewer 4 Report
I appreciate the authors' effort of revision. The manuscript will be acceptable after some technical correction.
@ There are two "Table 2"s (Lines 189 and 349). Tables should be re-numbered.
@ Line 416 "and it increases by about 806m for every 1m increase in the perimeter on average,"--- This part should be removed.
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Reviewer 5 Report
The authors made the corrections and suggestions given to improve the article. The presentation of the results and the quality of the graphic material has been adjusted and improved. Therefore, I recommend publishing the manuscript. Congratulations to the authors.
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