Response of Guobu Slope Displacement to Rainfall and Reservoir Water Level with Time-Series InSAR and Wavelet Analysis

Round 1

Reviewer 1 Report

The manuscript deals with critical issue of Reservoir Landslides. It is within the scope of the journal.

The paper is well-written and organized. further, improve the quality of the paper, the authors can consider the following points.

The literature review skips many recent papers published on the topic. It should be updated to include the recent studies. Also, the introduction should take into cognizance that the problem is worldwide and therefore should present the case studies across different countries done (Spain, Canada, India, Argentina, Bhutan, etc.) with InSAR. It can incorporate the following:-

https://link.springer.com/article/10.1007/s10346-021-01728-z

https://doi.org/10.1016/j.jappgeo.2022.104754

https://link.springer.com/article/10.1007/s10346-015-0583-4

https://www.mdpi.com/2072-4292/13/3/366

 

The SAR processing parameters used should be given (number of image, dates of images in supplementary material) in detail, since the experiments have to be in a form that allows readers to repeat the experiments.

Section 3.1 can be shortened. The technique in discussion in this section is established. So there is no need to delve much deeper into this.

What are the limitations of your study?

The continuous wavelet transform (CWT) is a powerful tool for analysing time series data, but like any methodology, it has certain limitations. Here are some limitations of CWT applied on time series data derived from SAR interferometry:

·        Sensitivity to boundary effects: The CWT requires that the time series data be truncated to a finite length. This truncation can introduce boundary effects that can affect the accuracy of the analysis. For example, sharp features near the boundaries of the time series can produce artifacts in the CWT.

 

·        Difficulty in selecting the wavelet: The CWT requires the choice of a wavelet function, which can have a significant impact on the analysis results. Selecting an appropriate wavelet can be difficult, especially if the characteristics of the time series are not well known in advance.

 

·        Computational complexity: The CWT involves computing the wavelet transform at multiple scales, which can be computationally expensive, especially for long time series data. This can limit the practicality of using the CWT for certain applications.

 

·        Interpretation of results: The interpretation of CWT results can be challenging, especially for complex time series data. It may require additional domain-specific knowledge to fully understand the significance of the results.

 

·        Dependence on signal-to-noise ratio: The accuracy of CWT analysis can be affected by the signal-to-noise ratio of the time series data. In the case of SAR interferometry data, the accuracy of displacement measurements may be affected by noise in the interferometric phase.

 

it is important to carefully consider its limitations when applying it to specific applications such as analysing displacement data derived from SAR interferometry.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Reviewer’s Report on the manuscript entitled:

Response of Guobu slope displacement to Rainfall and reservoir water level with time-series InSAR and wavelet analysis

 

The authors utilize ESA Sentinel-1 imagery for studying the response patterns of reservoir bank landslide movements to rainfall and reservoir level changes via wavelet analysis. Though the topic and results are interesting, the presentation requires revisions. Below please see my comments.

 

Line 54. Please include the following article that talks about rainfalls triggering shallow landslides:

https://doi.org/10.4408/IJEGE.2019-01.S-17

 

Line 67. Please define PS. All abbreviations must be defined the first time they appear.

 

Line 84. Please also include the following most recent article for applications of cross-wavelet analysis in land cover and climate monitoring:

https://doi.org/10.1016/j.jag.2023.103241

 

Lines 120-121. Please remove.

 

Equations (1)-(6), etc. Many of these equations are not needed if you simply used the pre-processed datasets. You can simply refer to appropriate references instead.

Similarly in Section 3.2. Please see the second article that I suggested above and rewrite this section in a better way, i.e., when you use the previously developed algorithms, it is recommended to only describe them briefly with appropriate citations (reduce the number of equations). For example, there is a review article: “A Survey on Change Detection and Time Series Analysis with Applications” where authors describe all these mathematical equations.

Lines 149-151. Descending and Ascending geometry are not always useful for monitoring landslides, especially if the movement is perpendicular to LOS. These are some of the limitations of InSAR time series for landslide monitoring that can be mentioned in the discussion section.

 

Figure 3. Is not the first quadrant “X Leading” and fourth quadrant “Y Leading”. Does your X time series come first? Please carefully check.

 

Figure 2 and lines 362 and 369. The least-squares wavelet software described and applied in the second article above does not need resampling of the rainfall and water level time series. It does not also require any interpolation for displacement time series and can provide higher time-frequency resolution spectrogram (normalized spectrogram expressed in percentage variance) as compared to the classical XWT. Please review that article and discuss these in the discussion section and/or as future work.

 

 

Figures 5, 9, 10, 11, 12, 13. The font size of the texts and numbers should be enlarged. Generally, please enlarge the font size of the figures.

Figure 9. Please use different colors for Water level and P2. Currently, both are blue. You can use black color for water level.

Figure 10. Which curve is water level?

Figures 11,12,13. What is the unit of the color bar? Please add the label and unit. It would be nice to plot the time series above the spectrograms. You can see the second article that I suggested above.

 

Line 535. Please explain the direction of the arrows in the caption of Figure 12.

 

Figure 6. Jumps in the InSAR time series could significantly impact the estimation of the rate of change of deformation. Jumps may be caused due to rockfalls, earthquakes, or sensor defect. Again, these are limitations.

 

Thank you for your contribution

Regards,

Author Response

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Reviewer 3 Report

This is an interesting contribution to the existing literature, but the paper suffers from several shortcomings listed in the following comments.

-          The paper should be checked by a native.

-          A discussion section should be added.

-          The introduction should be updated by recent researches.

-          The novelty and contribution should be clearly bolded.

-          The authors should consider the following works:  

Transformer Winding Faults Detection Based on Time Series Analysis, IEEE Transactions on Instrumentation and Measurement 70, 1-10.

On the detection and estimation of the simple harmonizable processes. Iranian Journal of Science and Technology (Sciences), 39(2), 239-242.

-          It’s better to suggest some subjects for future works.

Best regards,

 

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Thank you for addressing my comments. Please increase the resolution and quality of your figures (minimum 300dpi) and carefully proofread the manuscript.

Regarding Figure 3. If X is first and Y is second then region 4 should be Y leads X not X leading. Leading means the maximum value of cycle in Y time series comes first then after some time the maximum value of cycle in X comes. Please carefully check this figure and the relevant text to avoid confusion.

Thank you!

Author Response

Thank you again for your patience and valuable time in reviewing our manuscript. In response to your question: "1) Please increase the resolution and quality of your figures (minimum 300dpi) and carefully proofread the manuscript.
2) Regarding Figure 3. if X is first and Y is second then region 4 should be Y leads X, not X leading. leading means the maximum value of cycle in Y time series comes Please carefully check this figure and the relevant text to avoid confusion. ", I have made the following changes to our manuscript:
Response: 1) Thank you for your careful review. We have carefully checked the resolution of the images in the manuscript and confirmed that all images are at 300 dpi or higher. Thank you for bringing this to our attention, and we apologize for any confusion.
2) Thank you for pointing out the problem in Figure 3 again. We apologize for our previous error persistence, and we corrected the error in Figure 3 and revised the text description related to Figure 3 by consulting relevant books and articles, which is shown in yellow text in the text. [Pg8, Ln316-319]

Reviewer 3 Report

Accept in present form

Author Response

Dear Reviewer,

We appreciate the thoroughness and thoughtfulness of your review, and we are grateful for the constructive criticism that helped us to improve the manuscript. Your insights and suggestions have significantly strengthened the quality of our work, and we could not have achieved this without your guidance. Thank you for your patience and dedication throughout the review process. we are humbled by the opportunity to contribute to the scientific community.

Best regards.