Detection of Coastal Erosion and Progradation in the Colombian ‘Atrato River’ Delta by Using Sentinel-1 Synthetic Aperture Radar Data

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

I have shared feedback within the commented PDF file, highlighting various aspects to consider while preparing the revised version.

Good luck.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Minor editing of English language required

Author Response

Thank you very much for reading our paper and for your recommendations. 
Please see the PDF file attached.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Examining SAR data instead of optical data, as implemented in this study, is noteworthy, given that SAR data enables data acquisition even in low-light and adverse weather conditions. Additionally, SAR provides very high resolution along with the capability to explore more features of the surface. I liked the idea of this manuscript, but I have a few concerns listed below to be clarified.

 1) Why did the authors implement the GRD version of Sentinel-1 data instead of SLC? GRD is already processed data and does not provide more flexibility in acquiring the features.

2) To make this work as a benchmark for erosion and progradation detection using SAR, the proposed methodology should start with a more general or ground version, i.e. SLC. Converting the SLC data into GRD forces us to lose some vital information that can be helpful for surface exploration. Either try to utilize SLC instead of GRD or at least justify why it has not been considered.

3) As mentioned in the paper, GRD is a processed version with multi-looking, speckle filtering, etc.; however, the factor of multi-looking for making square area pixels is not described well in the manuscript. For the readers of this manuscript to understand, this information is vital and must be included in the revised version. Also, the benefit of choosing the implemented speckle filtering technique needs to be mentioned. I appreciate the analysis on speckle filtering to show its benefit; however, "which one and why" still needs to be answered.

4) The decomposition approaches presented in the following manuscripts, for similar single transmission and two orthogonal reception conditions, can be useful in monitoring the changes based on different scattering contributions. 
[1] L. Mascolo, S. R. Cloude and J. M. Lopez-Sanchez, "Model-Based Decomposition of Dual-Pol SAR Data: Application to Sentinel-1," in IEEE Transactions on Geoscience and Remote Sensing, vol. 60, pp. 1-19, 2022.   

[2] A. Kumar, A. Das and R. K. Panigrahi, "Hybrid-Pol Based Three-Component Scattering Model for Analysis of RISAT Data," in IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, vol. 10, no. 12, pp. 5155-5162, Dec. 2017.
Please have a look at them and at least mention these approaches for the future extension of the presented work.

5) The resolution mentioned in the paper is 10.9028 m × 12.6222 m. Do you think that this resolution value considered the slant-range to ground range conversion as well as the multi-looking effect? Please explain this process and how this value is calculated.  

Other Corrections:
(a) Line 302: Page 11: You can remove "of" from this statement "robustness against of clouds or obstacles that might hinder"

(b) "VV" and "VH" in the text are mentioned in both italic and non-italic ways. Please make it uniform to avoid any confusion related to the symbols. 

 

 

Comments on the Quality of English Language

Minor corrections are required. I mentioned a few of them as "Other comments" provided to the authors. 

Author Response

Thank you very much for reading our paper and for your recommendations. 
Please see the PDF file attached.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This is interesting research presenting how SAR images can be used to study erosion and accretion in active rivers. It shows a very useful application of SAR remote sensing in areas with cloud issues. However, the manuscript needs improvement before it can be published. The most noticeable issue here is not having an accuracy assessment. Therefore, I recommend the authors revise the manuscript by (1) including accuracy assessments for the initial classification results and the erosion and progradation results, and (2) addressing the following specific comments:  

·       Must show the results of the initial classified images.  

·       Should show SAR images in parallel to Figure 2.

·       The scale in Figure 1 needs to be in format of 0-10 km.

·       Figure 3 needs a scale and a north arrow.

·       The scale in Figure 2 needs to be in format of 0-10 km.

·       Figure 7 needs a scale and a north arrow.

·       Figure 8 needs a scale and a north arrow.

·       Figure 9 needs more explanation including the legend key.

·       Figure 10 needs a scale, a north arrow, a legend, and more explanation.

·       Atrato river should be ‘Atrato River’.

 

 

 

 

 

Comments on the Quality of English Language

Minor editing of English language required. 

Author Response

Thank you very much for reading our paper and for your recommendations. 
Please see the PDF file attached.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Dear authors,

I have gone through the manuscript Detection of erosion and progradation in the Colombian Atrato River Delta by using Sentinel-1 synthetic aperture radar data. The author has done good work, but still, this manuscript needs little attention from the author.

• It is recommended to fully spell out the term in the first use of the term in a manuscript. Once the abbreviation has been introduced, it is appropriate to use it throughout the rest of the manuscript. So, readers will better understand the meaning of the abbreviation and its relevance to the topic at hand. For example, in line 12 of the abstract, Oceanic Niño Index (ONI), use the abbreviation ONI in the manuscript.
• Please clarify the gap in your study. What is the novelty?
• Introduction section: The introduction needs to be supported by a literature review of using optical and active remote sensing techniques to detect erosion and progradation in delta zones. Please add some specific literature. I think the authors could read them and cite them. please see

Abou Samra RM, Ali R (2020) Applying the DSAS tool to detect coastal changes along the Nile Delta, Egypt. The Egyptian Journal of Remote Sensing and Space Science, ISSN 1110-9823

Yang J., Dai Z., Lou Y., Mei X., & Fagherazzi S. (2023). Image-based machine learning for monitoring the dynamics of deltaic islands in the Atchafalaya River Delta Complex between 1991 and 2019. Journal of Hydrology, 623, 129814.

Danchenkov A., Belov N., Bubnova E., & Myslenkov S. (2023). Foredune defending role: vulnerability and potential risk through a combined satellite and hydrodynamics approach. Remote Sensing Applications: Society and Environment, 30, 100934.

 

• What is the source of figure 1?
• You should remove repeated information about the advantages of using SAR data due to cloud conditions from the full manuscript.
• What are the advantages and disadvantages of Otsu's method?
• The results section should be well written. In Section 4.2, “Erosion/Progradation Detection and Measurement," I suggest moving the first paragraph, lines 284–288, from Results to Methods. Additionally, what do these numbers (20160611 vs. 20161214 and 20210627 vs. 20220228) refer to?
• You should add a part in Results Section 4.2 about the results of Table 1 as visualised in Figure 11. You should add a paragraph about the measurement and comparison of areas of erosion and progradation from 2016 to 2023.
• You should compare your results with previous studies that used SAR or optical data in this study region to estimate erosion and progression.
• You should assess the accuracy of your results.
• What are the limitations of your study?
• Where is the conclusion section?

Author Response

Thank you very much for reading our paper and for your recommendations. 
Please see the PDF file attached.

Author Response File: Author Response.pdf

Reviewer 5 Report

Comments and Suggestions for Authors

In general, the work is structured in a confusing way, several elements are located in regions that they should not be.

An example is in the introduction, the comparison between the delineation in GEE and arcGIS is addressed, however this comparison disappears throughout the text. Still regarding the introduction, normally the final paragraphs are reserved to indicate the objectives of the work and the structure, which is not the case. In fact, the structure of the work is explained, but the objectives are not clarified.

Another example of this is the item Detection and measurement of erosion/progradation, part of what is covered in the item should be in the methodology and not in the results.

Another worrying factor is the results, the work does not compare results obtained with other methodologies, making the evaluation of the technique difficult. Combining statistics with the classification of multispectral images at moments close to the SAR images could help in evaluating the methodology.

Ultimately, we concluded that the manuscript is not suitable for publication in this journal.

Yours sincerely,

Comments on the Quality of English Language

I believe that a review should be carried out with the help of a translation service, such as the journal itself.

Author Response

Thank you very much for reading our paper and for your recommendations. 
Please see the PDF file attached.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for your dedication to revising the manuscript in accordance with the feedback and suggestions from the reviewers. Congratulations!

Author Response

See attached file

Reviewer 2 Report

Comments and Suggestions for Authors

The clarification report is satisfactory. It can be published now.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Thanks for revising the manuscript as suggested. It is in much better shape now. I still recommend revising the manuscript further by addressing the following comments:

·       Figures 4, 5, and 6 need more explanation in the caption.

·       Figures 3, 7, 8, 10, and 11 need a scale, a north arrow, and a legend.

Comments on the Quality of English Language

Minor editing of English language required. 

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The manuscript is acceptable in the current form scientific point of view

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 5 Report

Comments and Suggestions for Authors

Considering the corrections made and meeting the demands we suggested, and the aspect of the final format of the manuscript, we are in favor of its publication.

Author Response

Please see the attachment

Author Response File: Author Response.pdf