A Partial Reconstruction Method for SAR Altimeter Coastal Waveforms Based on Adaptive Threshold Judgment

Round 1

Reviewer 1 Report

Dear Authors,

Your paper presents a significant improvement in SSH measurement solutions. The two chosen study areas show certain differences which were outlined in the manuscript.

The reviewer found the introduction and the presentation of scientific background adequate where the problem for which this method provides an alternate solution resulting in higher accuracy. The methodological steps are presented clearly and have good scientific soundness yet are understandable.

Figures, Tables and Equations are well-edited, and all have the same styles hence not only help a better understanding but are very attractive. It could be more improved if the grid or ticks of the coordinate system would be marked on Figure 1 maps, not only the coordinates themselves next to the axes.

The part of results seems well-considered and impressive. Conclusions are clear, however, some links to other literature may enhance the quality of this part.

References seem to be adequate, as well.

My overall impression is that a detailed study of the manuscript is positive and I recommend it to be published after minor work on the part Conclusion.

Regards,
   Reviewer

Author Response

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Reviewer 2 Report

Dear authors,

Thank you for submitting this manuscript. You propose a novel processing method for SAR altimeter coastal waveforms. The structure of this manuscript is well designed, the logic is detail described and the experimental results verify the effectiveness of the proposed method. I have a few comments.

 1. It is recommended to add a north arrow and a scale bar in Figure 1.

 2. Check whether the abbreviation of mean square error (MQE) defined in the article is correct.

 3. The explanation of MQE improvement proportions in Table 1 and Table 2 is not detailed enough.

Author Response

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Reviewer 3 Report

This manuscript proposes a partial reconstruction method for SAR altimeter coastal waveforms. The contaminated coastal waveforms are partially repaired based on adaptive threshold judgments of model matching errors, and the processing results of Sentinel-3 satellite data has proved that this method improves the SSH precision by a factor of two. Considering the poor accuracy of SSH obtained from altimeter coastal data, the topic of this article has academic and application value. The conclusions are consistent with the evidence, and the references are appropriate.

A few minor comments for improving /clarifying even further:

1. Line 185-191:

In Figure 3, several typical coastal waveforms are displayed. Some detailed explanation about scattering characteristics of the observation surface should be added, therefore, the readers can better understand why the waveforms are different from the standard ocean waveform.

2. Line 258-260:

The OCOG method is widely used in this study, thus the calculation principle should be given here.

3. Line 368-371, Line 376-401:

The SSH and SWH are retrieved from the leading edge of waveform, therefore, the leading edge should not be changed/reconstructed. Is this taken into account in the judgment criterion? In Figure 7a, the leading edge of the reconstructive waveform is coincident with that of the original waveform. Does this apply to the whole dataset?

4. Line 470:

Why the threshold is set to 0.008? Some statistical results should be added to explain the reason.

5. Line 590-627:

In the Conclusion section, the authors list four conclusions. However, point (1) and (2) are materials and method not conclusions. Therefore, the language of this section need to be reorganized.

Author Response

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Reviewer 4 Report

The manuscript is concerned with improvements to the accuracy of sea surface height derived from SAR altimetry in coastal areas which is complicated by the heteorogenity of the scenes.  This topic is relevant in this area of research and new approaches that yield better results are most welcome and needed. The authors introduce a new method termed Adaptive Threshold Judgement which they demonstrate to improve the accuracy of sea surface height determination by SAR altimetry. The two study areas are well chosen as the pinpoint the issues that the authors are trying to address with their new technique. The improvements due to their new approach are clearly and convincingly demonstrated in their paper. The references have been adequately chosen. Tables and Figures are fine. The authors have actually invested clear effort to make the figures clear and appealing. The use of the English language is generally ok. I recommend publication in its current form.

Author Response

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