Analyses of Variation Trends of Winter Cold Snaps in Subarctic and Arctic Alaska
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe scientific article submitted for review is devoted to one of the aspects of the effects of warming in the polar latitudes, namely, a decrease in the effectiveness of thermosiphons as a result of reduced exposure to winter cold. The article is notable for the relevance and originality of the author's approach. The article is written in good language, the illustrations in the manuscript are informative and visual. The title of the article corresponds to its content. The abstract of the article fully reflects its relevance, the main conclusions of the study and the directions of practical application of the results obtained.
The content of the article corresponds to the research areas covered by the MDPI Sustainable Engineering and Science journal, but contradicts the topic of the special issue of the journal - Protection and Utilization of Black Soil for Sustainable Highway Engineering. There are no chernozems in the Subarctic and Arctic.
General remarks and recommendations.
The authors of the article, while substantiating the relevance of the study, repeatedly address the problem of the effectiveness of thermosiphons. However, they provide very little information about what these devices are, where and for what purpose they are installed, and under what conditions they function. Given the interdisciplinary nature of the journal, I strongly recommend inserting such paragraph-sized information in the Introduction. At the same time, I would like to draw the authors' attention to the fact that the efficiency of thermosiphons primarily depends on the temperature difference between the stabilized soils and the above-ground radiator (condenser, heat exchanger). The efficiency of work is also influenced by design features, the coolant, and other climatic parameters besides winter air temperature, such as wind speed, precipitation, and humidity. Therefore, the authors should make a reservation in the Introduction that they know the complexity of the interaction of climate warming with artificial systems for stabilizing frozen and thawing soils, but in this article they consider only changes in the quantity and quality of winter cold spells.
There is another point related to these recommendations. It concerns the qualitative characteristics of the research objects. The choice of settlements in Alaska (USA) deserves every praise. However, the description does not contain information about the temperature of permafrost, the infrastructure of settlements (area and type of buildings, length of roads, number of buildings) and the practice of using thermosiphons. The authors need to supplement section 2. Location of research objects with such information. Subsequently, in conclusion, this will allow the authors to supplement the article with conclusions about the difference between settlements in the degree of danger of threats of loss of thermosiphons performance. And the differences between settlements in permafrost and climatic conditions are obvious.
Subsection 3.2. Historical average monthly air temperature contains an baseless use of the term "historical average air temperature" by the authors of the article. Such a term misleads the reader and requires each time to determine what is meant by this term: the entire period of observation or for specific years. Therefore, we strongly recommend changing the name of the subsection (for example, Long-term and short-term average monthly air temperature) and replacing all such definitions in the text of the manuscript.
Specific comments and suggestions
Lines 325-327. The phrase needs to be adjusted. For example, like this. Taking into account the fact that there is no generally accepted definition of the term "winter cold snap", we propose the following definition: winter cold snap is a period when the average daily temperature is lower than the long-term average monthly temperature of the winter period.
Line 376. Edit as follows: ",where FREQ - frequency, TEMP - temperature, WET - low winter air temperature."
Lines 538-540. We recommend correcting the phrase. For example, like this. Analysis of winter cooling trends in subarctic and Arctic Alaska, taking into account factors such as climate warming and natural fluctuations in climatic parameters, is crucial for optimal use of the thermosiphon.
Drawings.
General requirements.
All drawings require increased resolution to varying degrees. The resolution must be at least 300 at a scale of 100%.
The font in the drawings should be uniform and correspond to: Arial; the main inscriptions are size 10, the secondary inscriptions (coordinates) are size at least 8 at a scale of 100%.
All diagrams (margin size) should be the same size within a single drawing (required) and the entire article (desirable).
The figures on the four diagrams should contain only letter designations without specifying the city in parentheses. The letter should be part of the drawing, located in the center above the diagram with a dot at the end. Arial font, highlighted in bold, size 12. In the first picture, the caption should indicate which letter index corresponds to the location. In the following figures with 4 diagrams, make a link to the first figure, which describes the symbols.
Recommendations.
We recommend placing figures with 4 diagrams in the text on the insets of sections with a horizontal orientation. This will increase the size of the diagrams and simplify the formatting of the manuscript.
Comments on the Quality of English LanguageSubsection 3.2. Historical average monthly air temperature contains an baseless use of the term "historical average air temperature" by the authors of the article. Such a term misleads the reader and requires each time to determine what is meant by this term: the entire period of observation or for specific years. Therefore, we strongly recommend changing the name of the subsection (for example, Long-term and short-term average monthly air temperature) and replacing all such definitions in the text of the manuscript.
Lines 538-540. We recommend correcting the phrase. For example, like this. Analysis of winter cooling trends in subarctic and Arctic Alaska, taking into account factors such as climate warming and natural fluctuations in climatic parameters, is crucial for optimal use of the thermosiphon.
Author Response
Please see the attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors
Unfortunately, many years of experience in the construction and operation of various facilities in the cryolithozone does not completely eliminate the numerous cases of deformations of these facilities, often of an emergency nature. An additional tension in the situation is caused by the global warming predicted by scientists and specialists for the near future. At the same time, there is no clear understanding of how climate change affects individual infrastructure elements today. In this regard, the presented manuscript is very relevant. The impression of the manuscript is generally positive, judging by its content, it is based on the analysis of a large array of meteorological data. I find this manuscript and the results interesting, but I recommend that the authors pay attention to the following points.
1. The authors of the manuscript constantly emphasize that the characteristics of winter cold snaps will determine the effectiveness of thermosiphons in Alaska. However, the manuscript does not provide quantitative data on the operation of thermosiphons in relation to the authors' research. For example, to what level should the duration or frequency of winter cold snaps decrease in order for the thermosiphons used in Alaska to become inoperable? Or other quantitative data. Despite the undoubted practical component of the study, the question is "What will happen to thermosiphons in Alaska?" not disclosed.
2. Line 198 "The area is dominated by warm, continuous permafrost". Please specify what is meant by "warm permafrost".
3. Information about the temperature regime of soils in the studied territories will be useful to the reader. Please consider adding information to the manuscript.
4. Please consider adding some data to the manuscript on snow, ice and wind for the studied objects according to the term on page 2 line 71.
Have a nice day.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for Authors1. Why does the work use only "Winter Cold Snaps" and meanwinter temperatures? If the article touches on the topic of thermosiphons, then it was worth considering the types and principles of operation of modern thermosiphons. At what air temperatures can modern thermosiphons work effectively?
2. Lines 141-142. Utqiagvik Is NOT the largest city within the Arctic Circle.
3. What data is analyzed in the work? Is it an open source? Why is there no link?
4. Data analysis – Figure 2.
- Why is the data divided into 2 segments and why is the year 1975 taken beyond the dividing line?
- Perhaps the same scale along the vertical and horizontal axes for all graphs will more clearly demonstrate the rate of warming and temperature levels.
5. Data analysis – Figure 3.
- why is the data divided into 4 segments of 25 years, whereas in the previous graph it was divided into 2 sections of 50 years? It was more logical to carry out the same division in all the work. Or explain why the selected intervals are used in one case or another.
- Perhaps the same scale along the vertical axis for all charts will more clearly demonstrate the difference in mean monthly air temperature.
6. Fig. 4. As in the figures above, it is preferable to see the same scale along the vertical axis, which would allow us to compare the plotted curves in different cities with each other.
7. Fig.10-11. Why is FI divided into 4 categories? Why do different cities have different FI limits? Why is the moving window 20 and 30 years? At different scales, it is difficult to analyze histograms when comparing different cities.
8. Line 509-510
What does " consistent with the broader Arctic warming pattern[36]" mean? What is special about this particular model? The paper does not carry out a quantitative comparison with the work [36]. Therefore, we can say that the result obtained is consistent with a couple of dozen more climate models. Perhaps there were some quantitative comparisons with [36]?
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors have done a good job of correcting the manuscript of the article in accordance with the comments made earlier. The reviewer believes that the manuscript can be published after verification by the technical editor of the journal and the English language editor.
