Spatial Variability of Active Layer Thickness along the Qinghai–Tibet Engineering Corridor Resolved Using Ground-Penetrating Radar

Round 1

Reviewer 1 Report

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Author Response

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Reviewer 2 Report

 

 Active layer thickness is one of the most important variables ro show the permafrost changes. This study investigated the spatial distribution of ALT along the QTEC in detail based on GPR. Given the importance of QTEC, it requires a lot of work to provide a datasets reference for the protection of engineering facilities. Therefore, the work present here is significant important. The findings of the paper are interesting, and the authors provided reasonable analyses and discussions. Overall, the paper is well organized, and the writing is concise and clear. In my opinion, the paper is publishable in Remote Sensing. I provide some comments below, which may help the authors to further improve the manuscript. I would recommend a minor revision of the paper at this point.

1. The CMP survey is described in Section 3.1 of the article. It is known that each GPR profile corresponds to a CMP data, but how many times are the transmitting and receiving antennas progressively moved apart for each CMP data?

2. In the second line of Figure 3, the positions of “CMP data” and “Common-offset data” tags need to be exchanged.

3. The labels on the horizontal and vertical axes in Figure 4a can be larger for easy reading.

4. The sentence in the first paragraph of 4.3.1: "This is thought to be the case because the vegetation of the QTP is controlled mainly by precipitation rather than by temperature.", you need to add a citation here.

5. In the second paragraph of 4.3.1, put “i.e. P<0.01” in brackets.

6. In the second paragraph of the Discussion, what does this sentence mean: “The uncertainties may also stem from the reference dataset, especially at the fine scale”?

 

Author Response

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Reviewer 3 Report

Well written and presented paper. The only issue I have with the paper is the use on P14 of the description "noise" to describe clutter.  Noise is considered  as randomly varying signals and is associated with internal noise in the receiver or external noise caused by transmitters in the same band or EMC issue with adjacent equipment.  The signals returned near water bodies are genuine, regular and fundamentally repeatable and while unwanted are caused by real artefacts. They are in fact clutter rather than noise. Hence this section needs to be approrpriately amended. The paper does not include any analysis of the statistical confidence of the comparison of the GPR results with ground truth derived from physical sounding and given the assumptions regarding the constancy of the propagation velocity for ALT this may be considered a real limitation. This issue needs to be addressed

Author Response

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Reviewer 4 Report

The article is difficult to read and understand because of the abundance of abbreviations in which the authors themselves get confused.

For example: what do the designations ^oC.d (line 26), ^oCd (lines 230 and 357) and ^oC (line 90) mean?

Are they the same?

I would recommend to the authors, if it is impossible to avoid the use of a large number of abbreviations, to provide a table of abbreviations used in the article.

In Figure 4, (a), (b) and (c) are missing, which are mentioned in the caption.

I would advise the authors to be more careful about editing the article.

Author Response

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