Analysis of Cooling and Humidification Effects of Different Coverage Types in Small Green Spaces (SGS) in the Context of Urban Homogenization: A Case of HAU Campus Green Spaces in Summer in Zhengzhou, China
, Handong Meng 3,4,†, Ruizhen He 2, Yakai Lei 2, Yuchen Guo 5, Amoako-atta Ernest 1, Sandor Jombach 1,* and Guohang Tian 2,*
Round 1
Reviewer 1 Report
The authors conducted an empirical study on the effects of various coverage types in campus small green spaces during summer in Zhengzhou (China). Different parametric scenarios and thermal behaviors were explored using experimental measurements and statistical analyses. Discussions and recommendations have been suggested based on the results. This manuscript is quite interesting. However, some points presented in the manuscript might need to be further improved and explained. Below are the comments to be considered for further work:
(1) The language is not satisfactory. Please proofread the manuscript carefully.
(2) Abstract: The abstract is too long. Please consider to simplify.
(3) Section 1: If possible, please add some recent studies of parametric meteorological simulation in the literature review, such as [Building and Environment 124 (2017): 153-170, https://doi.org/10.1016/j.buildenv.2017.08.011], [Energy and Buildings 186 (2019): 368-383, https://doi.org/10.1016/j.enbuild.2019.01.026], [Journal of Building Performance Simulation (2020): 1-17, https://doi.org/10.1080/19401493.2019.1707876], etc.
(4) Line 126: Please consider to use the Köppen climate classification for describing the climate in Zhengzhou.
(5) Table 1: If possible, please provide the standard deviation of each statistics in Table 1.
(6) Lines 158-159: The urban microclimate is partially caused by anthropogenic heat flux due to human activities, which usually consists of the heat from building operation, traffic vehicles, and human metabolism [International Journal of Climatology 31.2 (2011): 189-199, https://doi.org/10.1002/joc.2106]. For densely populated urban areas, the traffic- and pedestrian-related heat flux could be a significant contribution to the heat stress. I notice that the measurements were placed at 1.5 m above the ground, which could be influenced largely by the human activities. There is a possibility that the traffic or pedestrian may play important roles in the final results and the conclusions may not be very correct in terms of the green coverage. Is it true that the iButton sensors were placed away from the roads and/or parking lots so that vehicular and pedestrian emissions could be neglected? Therefore, the authors need to provide more details to convince the potential readers – or at least me – that the thermal profiles in the case studies were dominated by the green coverage.
(7) Line 200: Please explain this expression.
(8) Lines 255-256: I expected this study to be designed for the case of extreme hot conditions, as the authors have only selected those three days in August 2019. But here the authors stated that they avoided extreme hot conditions. Also, I notice that the measured maximum temperature was higher than the highest value of extremely high temperatures in history (Lines 264-265). This looks more like an extreme summer case. Therefore, please further explain and clarify what kind of scenario this study is design for. Average summer case or extreme summer case?
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper presents a case study to explore the effect of Small Green Spaces (SGS) on urban microclimate. The paper is well-written and may contribute to the knowledge area of urban heat island mitigation and more sustainable urban planning and landscape design. In addition, the research methodology is logical and reasonable for the collection and process of data. The results are rationally based on the data collected and discussions are conniving and pertinent to the topic. However, the paper needs to address the following issues before it can be accepted.
1. The literature review should include some urban homogenization theory.
2. Give a clear explanation of how PET is calculated.
3. When discussing the Influence of vegetation structure on microclimate, please cite the following paper, which shows that the combination of shade trees over grass is the most effective landscape strategy for cooling the microclimate.
Yang, W., Lin, Y., & Li, C. Q. (2018). Effects of landscape design on urban microclimate and thermal comfort in tropical climate. Advances in Meteorology, 2018, 2809649. doi: 10.1155/2018/2809649
4. Please double check spelling and punctuation. I have noticed some punctuations are missing.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
To the authors.
First of all I want to point out that I appreciate the work and research you did. Your revised article will contribute to help to understand the influence of vegetation in different levels on small green space (SGS), micro-climate, and the urban heat island (UHI) effect.
I was asked to review your manuscript. Due to the amount of comments I chose a chronical way through the text referring to line numbers, figures and tables. Keep in mind that even enhancing the text by reflecting my comments might lead to new questions and comments.
There is one significant research item in your article I would like you to reconsider. You are using the Relative humidity (RH) as the indicator for humidification throughout your research. As you pointed out yourself, RH has a strong relationship with air temperature (AT), when AT increases, RH decreases. This happens under all circumstances, even when the water vapour, as a measure of water in a certain amount of air, is constant. Therefore, you cannot conclude, that the air masses at measurement spot A (impervious spot) is drier as in spot B, C, or D, when die AT degreases towards spot D, because by change all spots could have the same air mass with the same amount of water vapour content. Is this clear? You should go back to measurements and calculate the Absolute humidity (AH) as a measure you use explain the humidity conditions in the parks. Because this is a fundamental item you have to change, I will not post any comment on RH here anymore.
I will give recommendations on text, tables and pictures referring to specific line numbers. You might accept them or not.
Line 20: insert ‘extreme’ before Urban Heat Island.
Line 27: change ‘weather’ to ‘meteorological’.
Line 44: skip the word ‘can’.
Line 57/58: skip ‘and air pollution’, because your research is focused on SGS.
Line 66: Luke Howard was a chemist by profession.
Line 79: There is also point of view, that city centres as a whole might cooler, not only parks or water bodies. Especially in springtime city centres do not warm-up so fast as surrounding countryside.
Line 82: change ‘outgoing’ to ‘reflected’.
Line 94: ‘It has practical significance …’, I do not understand this sentence.
Line 97 – 99: ‘A series of homogenization … ‘, see line 94, and ‘copied and pasted’ are indeed not the best English, you can use. Try ‘transfer’, or something more explainable.
Line 107: a typo ‘in an university campus’.
Line 109: change ‘plots’ to ‘spots’.
Line 116 – 119: the bullet points 2 and 3 are already reciprocity to themselves.
Line 121: A comment: Because you did not specified the properties of the four measuring spots, one area of the four with all needed vegetation characteristics would be enough to provide the meteorological data for your research. But you also should include the size in square metres of each spot.
Line 125: Add the population density in numbers of Zhengzhou.
Line 131: ‘… so the energy exchange with the surrounding is relatively weak.’ What do you mean by that?
Line 134 – 140: Very good, but you should tell, which plant is in which garden. Or are they everywhere equal in number, height, habitat?
Line 146: remove comma after D and dot after Table.
Line 152: Table 1: include units for PAR, CD, LAI, MLA.
Line 157: Why do you wanted to reduce the influence of the wind speed? What other factors?
Line 159: You used printed paper cups. Why not simple white ones?
Line 163: Figure 2, the mounting of the paper cups above impervious and shrub-grass ground was adequate, in the tree-grass and tree-shrub-grass spots the cups are quite close to the trunks themselves, this could generate disturbance in the air temperature field. Also it could not be seen from the picture how high the measuring level in the stem area was.
Line 168 - 170: ‘Considering the wind speed …’. You showed later that the average wind speed of the measuring period was <0.1 m/s. This is generally speaking: no wind at all, calm. How large were the corrections to the results?
Line 194: Add a reference to ‘John Norman’.
Line 197: Open up the Formula: what is A and K? Add the units.
Line 212: A comment to Figure 3: Here you reveal that the research areas (Impervious and Shrub-Grass) were influenced by a significant amount of tree shading. This questioned your analysis, because not only the influence of the vicinity of shading trees on cooling and humidification is not clarified.
Line 231: change ‘environmental’ to ‘human’.
Line 232: change ‘climatic’ to ‘meteorological’.
Line 240: add a ‘.’ after weather.
Line 243: You used a 12-hour clock system. You have to change all hours in the afternoon to this, here 13:30pm to 01:30pm.
Line 251: change ‘historical’ to ‘long-term’.
Line 256: Why do you want to avoid extreme hot conditions?
Line 258: Figure 4: Where are the observation from 2005, 2006, 2007, 2008, 2010, 2011?
Line 274 – 281: Including Figure 5. This section is irrelevant, because the mean wind speed was less than 0.1 m/s, without wind speed the seldom measured wind direction lose its relevance. If you want to include wind data use some from a near-by synoptical weather station.
Line 282 – Read the critical comments at the beginning!!!!
Line 311 – please check the value 90 degrees, you are not at the Equator, the angle should be less 80 degrees.
Line 323: remove the point after Table.
Line 325: Figure 7: to simplify the figure skip the upper-right half, it is the same information as in the lower-left corner.
Line 330: ‘The relative contribution order …’, what do you mean by that?
Line 351: ‘Infrared rays in sunlight …’, this statement is wrong, because the energy maximum of solar radiation lies in the visible range of the solar spectrum, at about 580 nm, the infrared area starts at around 720 nm.
Line 375: What do mean by ‘urban canopy heat island effect’?
Line 377 remove ‘could’ after which.
Line 378 – 380: Again the statements about air quality should be removed.
From Chapter 4 until the end of the article written language improves substantial, this is good, but there some sections in the text, where this is not the case, please try to unify the writing style.
In the conclusions chapter parts of untenable conclusions, should be rewritten after the revision.
And last not least in line 473: change ‘my’ to ‘our’ (twice) and for what you are thanking your team colleagues at Henan Agricultural University for?
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 4 Report
All my comments can be found in the attached document
Comments for author File: Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 5 Report
Refer to the attached file.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
All the comments have been well addressed.
Reviewer 3 Report
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