Sentinel-1-Based Soil Freeze–Thaw Detection in Agro-Forested Areas: A Case Study in Southern Québec, Canada

Round 1

Reviewer 1 Report

The reviewer’s comments on the manuscript “Sentinel-1 Based Soil Freeze-Thaw Detection in Agro-forested Areas: A Case Study in Southern Québec, Canada” by Shahabeddin Taghipourjavi et al.

The soil freeze-thaw cycle is an important typical feature of the spatiotemporal evolution of soil properties in cold regions. The use of satellite remote sensing data to identify soil freeze-thaw conditions has important scientific significance and application value. The authors of this researchers used Sentinel-1 satellite remote sensing data to identify the freeze-thaw state of in Agro-forested Areas. The obtained results have good reference and promotion value, and also promote the technical and theoretical development of satellite remote sensing soil freeze-thaw. The writing of the paper is standardized and the structure is complete. I recommend to accept this manuscript and publication

However, there are still some issues the authors need to carefully implement. As soil freeze-thaw is actually the result of soil temperature changes and water phase transitions, it can be well explained by using passive microwave remote sensing, because the soil temperature and soil water retrieved by passive microwave actually reflect the freeze-thaw state of the soil. What is the theoretical basis for using the combination of backscatter coefficients from active microwave remote sensing to identify soil freeze-thaw states? Or what are the principles of physics? The author needs to provide a comprehensive explanation. In addition, the author provided Figure A1, which shows a large range of changes in the backscatter coefficient under the same LIA. What is the reliability or reference value of the regression coefficient provided. The readability of Figure A2 is not very good, and the authors need to reprocess it to make it easier for readers to understand.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript "Sentinel-1 Based Soil Freeze-Thaw Detection in Agro-forested Areas: A Case Study in Southern Québec, Canada" (remotesensing-2872611). The present study raises extremely important points for the current scenario of climate change that the global population is facing. Thawing ice is a point in question that is extremely important to be studied. I congratulate the authors for the contextual elaboration, results, and significant discussions they present in this study, it will be essential for the scientific community and will be a reference. Therefore, I am recommending this work for minor revisions. 

As small observations, which must be attended to, I highlight: 

1 –Note that you are presenting an abstract with 303 words, and Remote Sensing limits an abstract to 300 words. I suggest the authors remove the following sentence: “Satellite-based remote sensing, utilizing both active and passive sensors, has proven effective in retrieving surface freeze-thaw (FT) conditions.”.

2 – In line 125, the authors call Figure 1, it is important that it is presented as soon as it is called in the text, and not two paragraphs after its first call. Furthermore, Figure 1 is in the middle of a paragraph comprising lines 135-144, please check the error made. In some figures and tables throughout the text, the authors make the same mistake, I suggest reviewing the entire work.

3 – The authors need to improve the representation of Figure 1. Note that you only focused on the study area, not providing any large-scale geographic representation, for the reader this needs to be clear!

It presents Canada, followed by the province/state, then the municipality and finally the authors present the study area. The focus can remain on your area, but the information I mentioned needs to appear on the map.

4 – I recommend that authors review the Remote Sensing rules, because at times authors apply paragraph indentation in figure titles (Figure 1), and at other times they do not apply paragraph indentation (Line 145).

5 – Line 251 does not need paragraph indentation.

6 – Sometimes authors place Figures in the middle of a paragraph, which makes reading very difficult!

Standardize the manuscript to Remote Sensing standards!

7 – Figure 9 should leave the Discussion thread!

8 – All Results Figures must have their quality improved to at least 600 DPI, as in the process of converting to PDF the quality is greatly reduced, and in the current format in which the work is found the figures are of low quality.

As a minor and main note, I highlight:

1 – Use the Mendeley Reference Manager for references as well as citations, as both Remote Sensing standards are not standardized in the body of every manuscript.

Minor editing of English language required.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

The manuscript is well developed with sufficient results and discussions. I have some comments which would be essential to better understand the manuscript.

L107: “lack of inflexibility”..It should be lack of flexibility?

L108:” Furthermore, it 1lacks generalizability across regions and soil types, as optimal thresholds may vary based on local conditions.” Authors are suggested to highlight the issues with such generalization?

L112:” explore deeper into the spatial and temporal dynamics of freezing probability to better understand its complexity.” What is the complexity of such dynamics, can be highlighted with reference.

Table 1. Nominal size of plots should be added. It helps readers to under stand the spatial scale is being studied.

Sec 2.2. L163: “At each plot, five soil pits equipped with two soil temperature sensors at near-surface (2 cm) and 10 cm depths were installed along a cross shape with 5m between each soil pit.” I would suggest to include a schematic figure to understand the sensing geometry of configuration.

Eq. (2): Description of Schaufler's equation is essential. What is beta factor?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf