Evaluation of the Stability of Muddy Coastline Based on Satellite Imagery: A Case Study in the Central Coasts of Jiangsu, China
Round 1
Reviewer 1 Report
19-22 it is not clear. I didn’t know that there was a difference between natural and artificial coastlines.
What do you mean with artificial coastline: we generally refer to the ports and to the structured river mouth
49 is siltation a synonymous of accretion?
50 You can start to reveal what you do image with remote sensing: satellite, remote video, drones other?
112 maybe coordinates are too much, you show them in the fig
151 reference?
188 maybe were calculated
191 the meaning of “erode”
Don’t you consider getting images from the same period of the different years? I think that I didn’t see it. Maybe you say later on.
301 Can you explain about the difference
You must clarify what you intend with artificial coast
Fig 4 Rather poor, can you live up the color?
321 of/by
You use often endpoint, what do you mean?
414 How width is the coast considered? How far from the coast is landward part of the reclaimed area?
Author Response
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Author Response File: 
Author Response.docx
Reviewer 2 Report
v. 28 – the phrase starting with „Areas…” is not clear
v. 50-52 – the phrase is worth to be rewritten
v. 66-67 – as tidal are periodic, wavy changes of different intensity need to be described otherwise
v. 98 – “annual coastline” seems to be a shortcut, not quite clear
v. 130-133 – in the (b) figure caption it is not mentioned about the current tide phase (supposing low tide)
v.196 – tidal data are not auxiliary, effectively are of primary value
v. 201 and the chapter 3.2 is showing the importance of tidal data, as mentioned above (not auxiliary)
Moreover – the term “coastline” here is to be more precisely defined, as it may be differently understood. As I can guess from equations (1) and (2) and fig. 3 it is established at the mean high tide line. It needs also an assumption that the slope is constant, not influencing the range of inundation (as it is different e.g. considering tidal channels or other obstacles). There is no mention of possible sources of uncertainty in the determination of the coastline.
v. 357 – e.g. of this expression consider a unified way of expressing changes in the direction of the coastline movement. Erosion rate as a negative value may suggest reverse process.
v. 446 – the chapter 5.2 – limitations and prospects – in the context of earlier considerations on changes in the coastline, issues such as changes caused by the diversification of the supply of sedimentary material to the coastal zone as a result of human activity in river basins flowing into the sea and its distribution by coastal circulation were not discussed (only Fig. 1a refers to the characteristics of the system waves). Similar issues are discussed in the paper by Du et al. 2019, Sediment Dynamics of Chinese Muddy Coasts and Estuaries, https://doi.org/10.1016/B978-0-12-811977-8.00003-0 not referenced here. The characteristics of sea level changes were also completely omitted, also in relation to land movements, described widely in the literature, having an undoubted impact on changes in the coastline over decades.
Not found a reference/discussion with very close paper by Xu et al. 2022 (Marine Policy, 139, https://doi.org/10.1016/j.marpol.2021.104887), using same resource of Landsat images for even longer period.
As mentioned above in some places phrases are unclear and need to be rewritten. It is worth to re-submit the entire article to language proofreading
Author Response
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Author Response File: Author Response.docx
Reviewer 3 Report
The central coast of Jiangsu Province has mostly silty and muddy soils, with gentle slopes and abundant tidal flat resources, which is one of the most typical regions to study the geomorphological evolution of tidal flats in China. Thus this MS provide the coastline changes in recent 30 years, and will help for the understanding of muddy coastal changes and reasons.
The article basically explaines the shoreline changes in the research area and provided quantitative results. However, the following issues have not been clearly explained
The methods about the abstraction of waterlines are credible, however, it is better to provide the related data, for example, the tidal flat slope?
It did not tell how to recognize the natural and artificial coastlines, using manual identification?
The 30-year coastline change can be divided into three stages. Why did the northern coastline begin to erode in the third stage?
Several sentences are repeated or have the same meaning. Especially in the introduction part. Review them and avoid repetitive statements in the same paragraphs.
Line 25: what do you mean by “erosion endpoint”?
Lines 50-53: the sentence is not coherent. Review the sentence.
Lines 130-131: “The orange shaded area” can’t be the “study area”. The authors should add that it is the “sand ridge” in the study area since it was well described in Figure 1 b. or they should change the caption for Figure 1a.. it will be repetitive to mention the same thing in Figures 1a & b captions.
Line 153: remove “st” from “North 50st”
Author Response
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Reviewer 4 Report
Review of Remote Sensing-2414349
“Evaluation of the stability of muddy coastline based on satellite imagery in the central coast of Jiangsu, China”
by Bingxue Zhao, Yongxue Liu and Lei Wang
General comments
The authors have carried out a very interesting research to study a long stretch of coast in Jiangsu (China). With the support of multi-source and medium-spatial resolution remote sensing images, the objectives of the ms are to (1) extract the annual coastline of the central coast of Jiangsu from 1990 to 2020 and quantitatively analyze the changes in natural and artificial coastlines; (2) calculate the distances and the rates of coastline change over many years with the support of a DSAS and analyze changes in the erosion and siltation of the coastline; and (3) quantitatively evaluate the stability of coastline along the central Jiangsu coast.
The paper is well written, easy-to-read and the organization is good. The title reflects the content of the paper, the objectives are clearly stated at the end of the introduction section and most illustrations are also in good shape. My main concern is the need to substantially improve the explanations provided in the methodology. With the current description, it is not clear to me that the analyzes carried out by the authors can be followed or repeated. Furthermore, the inclusion of the calculation of the precision of the results and the error (absolute and percentage) committed in the interpretation of the satellite images is absolutely necessary. Finally, I sincerely believe that the graphic presentation of the results is not the most adequate to be able to consider their importance.
Thus, in my humble opinion, the manuscript is not yet acceptable for publication but it would be by correcting these problems. Some specific comments and typos are listed below
Specific comments and typos
Line
20 Total length of the coast?
28 Please, check if the verb is missing from this sentence “Areas …coast”
75 Apart from this cite, the authors should include references from other researchers using the same or a similar method
115 Tidal range?
130 Please, check the meaning of the dashed lines in figure 1a
151-154 Position of the GCPs? Explanation of the correction methodology must be extended
163 What is the slope of the mud/tidal flat?
173 Please, provide the English version
183 A reference is needed for the water body ID
185 How many images? Periodicity? Sources?
187 Any reference for the correction methodology?
194 This sentence should be clarified: “… image elements less than a certain value”
195 Meaning is not clear enough.
207-223 This whole paragraph needs further clarification. Moreover, a sketch supplementary of fig. 3 is essential.
227 The two images in Fig. 3 are not enough to demonstrate the calculation process of the coastline.
231-232 Sorry, meaning is not clear enough to me.
234 Other authors who considered this process before should be cited.
258 How many profile lines?
259 Absolute value?
271-285 How much is small and/or large? Has this index used previously? Otherwise, what is the advantage of this method over others?
290-291 A table must be prepared with the data used, indicating date, source, etc.
291 The authors should find a way to show the 31 coastlines. Maybe another figure?
302 since … to … Moreover, the coastal length is not the same in both cases. Would you please check it or provide an explanation?
316 In Figure 4, why the different ports are not on the coastline?
325 Where could the reader check this reclamation length?
357 “m/a”? Do the authors mean “meters per year”
360 Maybe occurred instead of occured?
376 Relationship among the stability index values and this classification must be provided.
377 Natural breakpoint method should be mentiond in the methodology
411 Meaning of “spectral charactieristics”?
415 Are the km2 per year?
449-453 Estimated error? Absolute and percentage. Moreover, these “limitations” must be highlighted in the abstract and the conclusions.
485-487 This assertion is not entirely correct as long as an estimate of the error committed is not provided.
Author Response
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Round 2
Reviewer 2 Report
Thank you for your corrections of the manuscript. In the current version it gained clear and unequivocal order.
Author Response
Thank you for your positive comments on our work. More importantly, we sincerely appreciate the time and patience you spent on our manuscript with many valuable suggestions and careful grammatical corrections.
Reviewer 3 Report
No
Author Response
Thank you for your positive comments on our work. More importantly, we sincerely appreciate the time and patience you spent on our manuscript with many valuable suggestions and careful grammatical corrections.
Reviewer 4 Report
Thanks to the authors for the enormous effort put into making the suggested changes. This has resulted in a substantial improvement of the manuscript.
However, there must be an error in the numbering of the lines, because I have not been able to find the changes performed in the indicated place. Moreover, some of the explanations provided in the response to my suggestions should be incorporated into the text of the article. Please consider the following comments:
- R4C1 Please, include the total length of the coast
- R4C4 Idem about the value of the tidal range
- R4C7 Idem, the value of the mud flat
- R4C10 This interesting explanation should be included into the ms
- R4C17 Sorry, I was not able to find the references in page 6 line 211. Would you please check them?
- R4C18 Has this comment been included in the ms?
- R4C23 This explanation should be incorporated into the ms
- R4C24 Idem
- R4C31 Please, clarify it in the text of the ms
- R4C32 These lines correspond to the Authors Contribution section. Would you please check it? Please, remember that any statement included in the Conclusions should have been discussed previously in the ms
- R4C33 Idem in "We have modified the inappropriate expressions about the research significance in the revised manuscript (Page 14, Lines 461–465)."
Author Response
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