Analysis of Spatiotemporal Urban Temperature Characteristics by Urban Spatial Patterns in Changwon City, South Korea

Round  1

Reviewer 1 Report

This paper analyzes spatiotemporal air and surface temperature characteristics based on urban spatial patterns in Changwon City, South Korea. The premise is interesting and the topic is important and relevant. The paper, however, needs to go through a thorough revision in order to become suitable for publication in the Sustainability journal. 

The paper is based on an inadequate literature review. A huge body of research has been done on this topic but the authors fail to review them. The background or justification of this study, therefore, is never fully explained. The writing needs a lot of work in order to make a meaningful contribution and to clear up some confusion. What are the key research questions that the authors are posing? Why and how do they come up with these questions? What does the existing body of literature tell us about those questions/topics? Was this study really needed? Was it based on a gap the authors identified based on a literature review? The revised version of this paper needs to address these questions. 

Overall, the formatting needs improvement----be it the Tables, or paragraph organization. The maps are strictly okay and should be improved. Some legends need to be more legible. Images/graphics have poor resolution. 

The results and discussion section need to be edited. This section, in its current form, is too long. The section needs to be re-written. At times, the section becomes boring and monotonous. When revising, the authors should think about answering the research questions. Then they should discuss the implication of their findings. Why are they important? What are the contributions you are making? The conclusion section needs to be stronger. 

Overall, the paper has some good ingredients for a good paper. The authors, if interested, can easily make a major revision that would address some of the concerns mentioned above. All the best. 

Author Response

The reviewer has corrected and supplemented the points indicated. Overall, the background and purpose of the research were insufficient, and a clear description of the differentiation of the prior research and the purpose of the research was required. Thank you for your careful review of the deficiencies.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper presents very interesting research which fits to the scope of the journal. I have only minor comments which should be considered before publishing.

The findings of the research seem to be practical and useful for the decisions in urban development management. They are not revealing when it comes to the mechanism, but they show the influence in the described environmental conditions which vary worldwide. Based on the introduction, the Authors refer to the possibility of UHI measurement in-situ, as well as in the conclusions they highlight the possibility of selection of areas where urban greenery should be increased. However, I miss very important aspect of the of thermal conditions assessment before urban development (as we should avoid problems instead of solving these problems which we created earlier). The findings of the submitted paper might be helpful to set some general rules on the impact of specific spatial pattern into decision support systems, where possible impact of future actions is analyzed; check for instance: The Use of a Decision Support System for Sustainable Urbanization and Thermal Comfort in Adaptation to Climate Change Actions—The Case of the Wrocław Larger Urban Zone (Poland), Sustainability 2018, 10(4), 1083. By suggesting that approach of application of findings, there is a way to develop smarter and more sustainable urban settlements at the initial phase of their planning.

I have also one comment on editing the paper. Please include the units together with every value presented in the text (“%” in lines 173, 301 and 460; “°C” in lines 193 and 324).

I strongly encourage the Authors to correct the paper, as in my opinion after improvements mentioned above, it might constitute a valuable paper.

Author Response

Thank you for your careful review of the deficiencies.

Author Response File: Author Response.pdf

Reviewer 3 Report

General comment:

The paper addresses the relevant topic of the air/surface temperature relationships, widely studied in the literature, as well as the surface/air urban heat island phenomenon, in a trivial way and without the necessary scientific soundness and technical rigor. Also, the outcomes are not relevant and significant for this research topic, and nothing new is proposed. The use of the technical language and scientific terms is not accurate, often hindering the understanding of the work methods and results. Language needs to be improved.

Specific comments:

-The temporal interval and temporal resolution of the dataset is missing in both abstract and introduction.

The introduction does not provide a significant overview, especially from a technical standpoint, of the  air/surface temperature and surface/air UHI relationships, widely addressed in the literature.

Firstly, in order to avoid lack of understanding and unclear/incorrect references to variables, I suggest using throughout the text the terms LST (Land surface Temperature) when referring to surface temperature, to distinguish it from the air temperature. The use of urban temperature is unclear, since it is not evident if referred to LST or air temperature. The same for UHI: when referred to surface, use SUHI. A clear and comprehensive analysis of the differences between air UHI and SUHI, as well as of the relationship between air and surface temperature and the way to measure them can be found in the review paper Zhou, et al,. Satellite Remote Sensing of Surface Urban Heat Islands: Progress, Challenges, and Perspectives. Remote Sens. 2019, 11(1), 48. Therefore, I suggest to deeply modify the state of the art of the introduction, considering also the different biophysical features and relationships between LST and air temperature.

-Line 80: “Figure 1 shows the first planned area in Korea in the 1980s”. But after is written that Figure 1 shows a land use type map of 2010. Please, specify.

-Line 102-103: it is not clear how the atmospheric correction, specific of each passage with own climate condition, were performed.

-Meteorological stations: they provide air temperature (what is the sampling rate?). But in the text, sometimes the authors refer to surface temperature at these stations (table 3 caption). This aspect must be specified.

-Line 138: “profiles of the urban temperature”: what does the term ‘profile’ mean in this context? The same for “ASTER surface temperature profiles”.

-Urban temperature: this term is not clear when both LST and air temperature are investigated

-Line 155-159: this part is not clear

-Table 2: Please, specify in the caption the hour of the measurement (correspondent to satellite passage). The reference of Table 2 in the text is not proper.

Section 3.2: there is a mismatching between table numbers and explanation in the text.

-Section 3.2.1: the description is too long, and only to explain temperature values reported in a table. The same table number mismatching and too long description for section 3.2.2.

-Table 3 caption. “Surface temperatures (°C) measured at various meteorological measurement stations”. Are the satellite data at the pixel covering the meteorological station?

-Section 3.3.2: only a correlation among few points is found. It is far from a model describing the air/surface relationship, both daytime and nighttime: the literature provides more complex and robust models (in time and space) able to follow a complex relation. Also, as reported in literature, the accuracy of a model should be evaluated computing the RMSE on a set of data independent from the training data (i.e. the data used to infer the model). Therefore, a larger dataset is necessary to assess the model performance.

-Section 3.3: this part is not clear: are the LST of Figure 5 obtained from the satellite sensor?

-line 395: “explanatory power of the linear regression model…”: what is the explanatory power in a linear model?

-Overall, the paper describes LST data over the land cover pattern, whilst the role of the air temperature data in the methodological context is not clear. It seems only a long description of data and linear correlations with land covers instead of a new approach facing with this topic: nothing new is proposed.  

Author Response

Thank you for your careful review of the deficiencies. The important point of this paper is to understand how spatial patterns affect urban temperature and urban heat island. In order to predict the temperature distribution, the number of measurement points and various spatial patterns can not be considered. Therefore, the relationship between surface temperature and temperature was derived from the weather observation point. The relationship between spatial pattern and surface temperature is roughly analyzed for urban temperature effects. We think it is a study that can be scarce in many areas, but it is considered to be a very necessary study to prepare strategies and policies to mitigate urban heat island phenomenon in view of the city's sustainable growth. It is still a basic level of research, and we plan to carry out related research through additional research (using high-precision image and prediction models) in the future. Thank you.

Author Response File: Author Response.pdf

Round  2

Reviewer 1 Report

This feedback is based on the "red" marked text available in the revised version of the paper (assuming that these "red" marked text represent the changes from the earlier version). The authors have made a major revision to a few sections and it has certainly improved the paper. The revised literature review now provides sufficient background and rationale behind this study. The discussion and conclusion sections have been revised as well, along with a new tables. The writing has improved in general. However, there are still some minor issues with the paper which can be fixed easily. 

1) The quality of most of the figures is not up to the mark. They look grainy or coarse. 

2) There is styling issue in many parts. In particular, figures should have the caption on the same page. Check out Figure 2 as an example. A figure and Legend must be on the same page (please check out Figure 3). 

3) In-text citations must be numbered, according to the journal policy. On page 20, as and example, in-text citations are provided as "Zhou et al. (2018)" but it should be listed as a [number]. 

4) The Acknowledgement section need to be deleted because it only has instructions.

5) The size and type of the "red" marked text does not match with the rest of the manuscript. 

All the best.

Author Response

Thank you very much for your careful examination.

Point by point response were attached as files.

Author Response File: Author Response.pdf

Reviewer 3 Report

General comment:

In the responses, the authors state that “This study is not based on the development of a more accurate forecasting model, but rather a comparison based on the methods of previous research and general methods.” From the work, it is not clear the comparison performed, and what the authors mean with “methods of previous research and general methods”. At the end of the introduction, it is reported that “the purpose of developing an effective method to mitigate the UHI effect at the urban planning stage”. But the method seems to be a description of the LST relation with land cover/pattern, as well as a simple regression between air temperature and LST. The authors must report widely the literature papers dealing with the increase/decrease of the LST in relation to the change of the land cover area in an urban environment, in order to highlight the novelty of the proposed work and method. If the paper aim is to develop a method, such method should be explained in a clearer way and with a technical scheme enabling the reader to reproduce it.

Language and grammar need to be improved. Some sentences are too long and should be divided.

Specific comments:

Abstract:

 “LST were used 12 ASTER LST…”: the sentence is not correct. The grammar of the added sentences on line 14-16 must be revised.

-line 21: “area ratio of built-up areas”: the meaning is not clear.

-Overall, the abstract is not clear: how are the conclusion of the abstract (22-27) linked with the work aim and results? They seem decorrelated. What is the meaning and link of the linear regression analyses of the surface and air temperatures in this context? I suggest rewriting the abstract, with attention to the grammar, highlighting what is the aim of the work, its novelty, and the results supporting the conclusion drawn.

Introduction:

-the SUHI must be introduced on line 47, when LST from satellite sensors is introduced

-Line 51-57: the state of the art and the connection between SUHI and AUHI (or CLHI) is poor. It is not clear if the cited work [25-26] studied the AUHI,

- the meaning of the sentence “relationship between the in situ LST measurements and the surface temperature derived from satellite imagery” is not clear: LST and surface measurements are the same parameter, and it is not clear the relation with the previous AUHI topic. This part must be better addressed, explained and referenced.

-Line 64: “Although many researchers….”: the references are missing. In reference [27] many literature works are considered addressing SUHII variations at a local scale driven by land cover, land use and their changes, urban site characteristics, landscape composition and configuration.

-Line 61-79: explanatory references are missing

-Line 80-84: the sentence is too long. It must be divided. So, the aim of the work is to develop a “method” for UHI mitigation from the data from different data sources? It is referred to SUHI or AUHI or both? It is not specified.

-What is the technical basis of the proposed “method”, having the different data as input?

-The temporal interval and temporal resolution of the dataset is missing in the introduction.

Section 2.3:

-the description of the three method uses terms that sometimes confuse the reader. For instance: “we analyzed the characteristics of surface temperature depending on the area ratio by land-use type.” the area ratio by land-use type must be better defined from a technical point of view.

-Section 3.2 and related subsection: since explanatory tables are reported, the description in the text is too long and should be summarized, describing only the main outcomes.

-Figure 5: the text inside the panel 5 is not readable.

-Table 5 and others: in the caption, the meaning on “N” should be explained

-Figure 6 and 7: the x and y mane (with unit of measurements) must be reported in the plots, not in the captions.

-Figure 6 and 7: in the area ratio of built-up, for instance, if it is X%, the remaining (100-X)% can be covered of different land covers (barre, grassland, forest etc.) that can affect the LST in very different ways depending on their own percentage. Therefore, sometimes the R2 is very low, below 0.5. How are these uncertainties considered in the model the authors proposed?

-Line 430: “In particular, urban land showed the greatest increase in LST during the daytime in July and August, the two hottest months in South Korea. The effect of LST fall in woodland was lower than the effect of LST rise in urban land, which allows the assumption that the overall LST would increase provided that woodland and urban land have the same area ratio”. Firstly, the “effect” on what is lower or higher? Effect on people? On agriculture?

-Line 436: “0.21°C”: this difference is very small, maybe of the order of instrument accuracy or LST retrieval algorithm accuracy. The same or 0.08 °C on air temperature, also considering the uncertainties on linear regression.

-line 438: “Klok et al., (2012) [24] conducted in July, the mean…: the sentence has no grammatical sense. Also, why comparing a very different city in another continent? A more pertinent comparison should be reported.

-in the discussion, there are many missing references, since several papers studied the temperature increasing/decreasing by changing land cover areas.

-Line 477: “This study is different from previous research in that it analyzed the urban temperature

 characteristics under various spatial patterns and temporal conditions”. It seems that there are not previous papers analyzing surface and air temperature in different time and space. Please, carefully review the existing literature.

-sometimes, the reference to papers in the text is not uniform (number or only author name)

Author Response

Thank you very much for your careful review. Due to the careful review, the quality of this study seems to have become an opportunity to get even higher. There are some parts that are insufficient. If you have any other changes, please let me know what you think.

point by point response were attached as files.

Author Response File: Author Response.pdf

Round  3

Reviewer 3 Report

The authors made a great effort to improve the manuscript following my suggestions, in both the revisions.

Now, it can be considered publishable.