Hydrodynamics and Sediment Transport at Socheongcho Ocean Research Station, Korea, in the Yellow Sea

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

I have recently completed my review of your manuscript which presents an in-depth analysis of long-term observational data from the Socheongcho Ocean Research Station (SORS) in Korea. Your work provides valuable and unique insights for the marine science community, contributing significantly to our understanding of the hydrodynamic and sedimentary processes in the Yellow Sea. The manuscript is well-written and the data meticulously detailed, which I believe will earn it deserved attention in the near future. I recommend its publication following minor revisions.

Here are some specific suggestions for improving the manuscript:

1. Please include photographs and diagrams of SORS to give readers a clearer picture of the research station's layout and operation.

2. In Fig. 4C, it is unclear what the blue and red lines represent. Please provide explanations or labels for these lines.

3. In Fig. 9C and D, there seems to be a unit error. The units should be in kg/m^2.

4. The cumulative water flux and sediment flux are important results of your study. However, the manuscript only provides the cumulative water flux and sediment flux per unit area for the upper and lower water layers. I suggest you calculate and present the cumulative water flux and sediment flux per unit width, i.e., the vertically integrated per unit area cumulative water flux and sediment flux. Given the stratification, you might want to provide the unit-width cumulative water flux and sediment flux for the upper and lower halves of the water column separately. This information will likely be of greater interest to the readers.

I hope these suggestions prove helpful in refining your manuscript. I look forward to seeing the final version of your work and believe it will make a significant contribution to this field.

 

Author Response

I have recently completed my review of your manuscript which presents an in-depth analysis of long-term observational data from the Socheongcho Ocean Research Station (SORS) in Korea. Your work provides valuable and unique insights for the marine science community, contributing significantly to our understanding of the hydrodynamic and sedimentary processes in the Yellow Sea. The manuscript is well-written and the data meticulously detailed, which I believe will earn it deserved attention in the near future. I recommend its publication following minor revisions.

We would like to express our appreciation for your positive and constructive comments. Your suggestions, especially those related to water flux and sediment flux, have significantly contributed to improving the quality of our manuscript. We have carefully incorporated each of your comments into the revised manuscript. Please find our detailed responses to your comments below:

Here are some specific suggestions for improving the manuscript:

Please include photographs and diagrams of SORS to give readers a clearer picture of the research station's layout and operation.

Following your suggestion, we have added a photograph and schematic diagram of SORS to offer readers a clearer understanding of the research station's layout and operation.

In Fig. 4C, it is unclear what the blue and red lines represent. Please provide explanations or labels for these lines.

Thank you for pointing it out. We have included a sentence in the caption of Figure 4C, explaining that the black line corresponds to surface temperature, while the blue line represents bottom temperature.

In Fig. 9C and D, there seems to be a unit error. The units should be in kg/m^2.

Thank you for bringing this to our attention. We have corrected the unit error in Figure 9C and D to 'kg' by integrating water flux and sediment flux over width, depth, and time.

The cumulative water flux and sediment flux are important results of your study. However, the manuscript only provides the cumulative water flux and sediment flux per unit area for the upper and lower water layers. I suggest you calculate and present the cumulative water flux and sediment flux per unit width, i.e., the vertically integrated per unit area cumulative water flux and sediment flux. Given the stratification, you might want to provide the unit-width cumulative water flux and sediment flux for the upper and lower halves of the water column separately. This information will likely be of greater interest to the readers.

As you suggested, we computed the cumulative water flux and sediment flux for both the upper layers (surface to 22 m depth) and the lower layers (22 m depth to the bottom) of the water column (Figure 9). The flux was integrated over depth, unit area, and time. The observed patterns of water and sediment fluxes mirrored those of the surface and bottom layers.

I hope these suggestions prove helpful in refining your manuscript. I look forward to seeing the final version of your work and believe it will make a significant contribution to this field.

We believe these revisions have strengthened the manuscript, aligning it more closely with your insightful comments. Thank you for your time and thorough review.

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript intends to clarify the hydrodynamics and sediment flux patterns (and their seasonal variability) on the Yellow Sea circulation along the Korean Coast, using monitoring data from an Ocean Research Station (SORS).

Essentially, it is an exhaustive and not always enlightening description of the instruments installed and the methodology used in data collection and analysis procedures. Some references in section 2.2 Data Collection would certainly help the reader.

Furthermore, until possible publication, many other aspects throughout the manuscript must be carefully reworked.

Abbreviations/acronyms should be defined upon first mention and used consistently thereafter. Therefore, acronyms should not be used in the Abstract without their prior definitions. Keywords that already exist in the title should also be avoided.

A calibration process requires the comparison of results obtained by different tools or methodologies. Therefore, the reader will expect to find well-founded calibration results of the ADCP acoustic backscatter intensity (section 2.3).

Given the scarcity of data and the possible insufficient representativeness of the data used for a more elaborate analysis, I am not sure that the discussion and conclusions are entirely reliable regarding the inter-annual behavior of the various parameters.

Furthermore, the Conclusions should suggest recommendations for future research in the field.

Regarding the figures, their legends and captions:

- The caption of Figure 1 must include the meanings of the color and line thickness. 

- Consider enlarging Figure 2 slightly to clarify and make the legends easier to read. Additionally, color legends must include SI units, and a legend of the color lines in 2B must also be provided  (section 2.3).

- Figure 4 should provide greater clarity, especially at vertical scales. The authors should consider a better arrangement of this figure, possibly considering two figures separating atmospheric data and oceanographic data and expanding the y-axis scales.

- As with Figure 2, consider enlarging Figure 5 slightly to clarify and make the color legends easier to read. However, it should be noted that the working data presented in this Figure (Figure 5) and also in Figure 7 (sections 3.2 and 3.3) are too scarce for a sufficiently well-founded analysis of the processes' behavior. It is also unclear whether 2018 is sufficiently representative. Why was data after 2019 not used?

- As with Figures 2 and 5, consider enlarging Figure 7 slightly to clarify and make the color legends easier to read.

- For better clarification, consider separating the cumulative flows slightly and enlarging the vertical scales in Figure 9. The dashed line should also appear in the legend of this figure.

Comments on the Quality of English Language

The English language and style are fine; just a minor spell check is advised.

Author Response

Please see attached file.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors,

I was asked to read and revise your article “Hydrodynamics and Sediment Transport at Socheongcho Ocean Research Station of Korea in the Yellow Sea”, you proposed for publication to Water. 

I found your research interesting and the text well presented, so I am going to suggest the Editor to accept the MS for publication, after minor revisions.

Beyond the comments you may find in the attached file, I would like to propose a few points to your attention:

1) I am not enough competent to propose changes of style and language, however I have a few doubts about some sentences and the choice of terms, which probably a minor revision by a native English could help to clarify.

2) The MS is well structured, and only minor changes are needed. Nonetheless, in some cases (e.g., section 2.1 Study Area, lines 143, 271-276, 433-434) I think the text can be moved or integrated.

3) Regarding the results, the fact that the direction of the sediment flow remains the same, regardless of the season and the presence or absence of water stratification is only partly interpreted: it is true that further studies and a global approach to the sediment transport in the Yellow Sea are needed, however some hypotheses should be proposed.

Hope my comments could have been somehow useful at this stage.

Kind Regards

The reviewer

Comments for author File: Comments.pdf

Author Response

I was asked to read and revise your article “Hydrodynamics and Sediment Transport at Socheongcho Ocean Research Station of Korea in the Yellow Sea”, you proposed for publication to Water. 

I found your research interesting and the text well presented, so I am going to suggest the Editor to accept the MS for publication, after minor revisions.

We would like to express our appreciation for your thorough, positive, and constructive comments. We have carefully incorporated each of your comments in pdf into the revised manuscript. Please find our detailed responses to your comments below:

Beyond the comments you may find in the attached file, I would like to propose a few points to your attention:

1) I am not enough competent to propose changes of style and language, however I have a few doubts about some sentences and the choice of terms, which probably a minor revision by a native English could help to clarify.

We thoroughly review the manuscript and made an effort to incorporate as many of your comments as possible regarding English usage. However, we opted to retain some of them as we felt they were better in their original form.

2) The MS is well structured, and only minor changes are needed. Nonetheless, in some cases (e.g., section 2.1 Study Area, lines 143, 271-276, 433-434) I think the text can be moved or integrated.

We thank you for your suggestions for significantly improving the quality of this manuscript.

• We created a new chapter (Chapter 2) for the study area. Then, the previous Chapter 2 has been renumbered as Chapter 3.
• We retained Line 143 unchanged as the salinity sensor was considered a component of the surface instrument.
• Lines 271-276 have been moved to the Discussion section.
• Lines 433-434 have been removed since the first paragraph in the introduction essentially conveys the same meaning.

3) Regarding the results, the fact that the direction of the sediment flow remains the same, regardless of the season and the presence or absence of water stratification is only partly interpreted: it is true that further studies and a global approach to the sediment transport in the Yellow Sea are needed, however some hypotheses should be proposed.

Yes, we are planning further collaborative research between Korea and China to enhance our understanding of flow circulation and sediment transport processes in the Yellow Sea. While we have a working hypothesis regarding the southward sediment flux concerning the SSC over tidal phases, it is premature to disclose it in this manuscript.

Hope my comments could have been somehow useful at this stage.

We believe your comments have been very helpful in enhancing the quality of the manuscript. Thank you for your time and thorough review.

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors made an effort to improve the manuscript following my comments and suggestions. Overall, the manuscript has improved substantially, although there are three points that authors should still take into account:

- A calibration procedure is performed to validate a methodology and for readers to have confidence in the results and conclusions. However, the calibration results presented in Figure 3 can hardly be considered encouraging (very scattered results, skewed regressions, low correlation). I would like to see a discussion (appropriate comments) about this (how, why, and then).

- Some Figures are still not fully enlightening and should be improved, especially Figures 4 and 5 regarding the definition/detailing of scales/vertical axes (possibly expanding even further). What can the reader conclude about the velocity profiles in Figures 5D and 5E? How representative are the color scales shown?

- I understand that the study will have to be limited to using the few available data, but the scarcity of data must be assumed and included in the Conclusions as a weakness of this study. It should also be emphasized that it is important (and should also be included) to deepen the analyses carried out with a more substantial set of data (no less than two to three full years).

Comments on the Quality of English Language

The English language and style are fine; just a minor spell check is advised.

Author Response

The authors made an effort to improve the manuscript following my comments and suggestions. Overall, the manuscript has improved substantially, although there are three points that authors should still take into account:

Thank you for your comments. We have addressed the reviewer’s comments and substantially revised the manuscript.

- A calibration procedure is performed to validate a methodology and for readers to have confidence in the results and conclusions. However, the calibration results presented in Figure 3 can hardly be considered encouraging (very scattered results, skewed regressions, low correlation). I would like to see a discussion (appropriate comments) about this (how, why, and then).

We agree with the reviewer. The low SSC range and its weak correlation with OBS calibration can be attributed to the low concentration of sedimentation at the study site. However, the MRE values for the ADCP-backscatter conversion were satisfactory, ranging between 10-40% in other environments. Thus, we added the following sentences.

[Lines 264-269] “The relatively weak correlation observed in the low SSC range for the OBS calibration (Figure 3C) can be attributed to the overall low concentrations of sediment at the study site. However, the mean relative error (MRE) of the ADCP backscatter calibration, reaching as low as 20%, appears to be good given that the MRE values for ADCP-backscatter calibration fall within the range 10-40% in various environments [22].”

- Some Figures are still not fully enlightening and should be improved, especially Figures 4 and 5 regarding the definition/detailing of scales/vertical axes (possibly expanding even further). What can the reader conclude about the velocity profiles in Figures 5D and 5E? How representative are the color scales shown?

 Figure 4 has been modified to better represent the environmental conditions at SORS in 2018. In particular, the monsoonal characteristics of winds and waves are now more accurately depicted, addressing your suggestion.

Originally, Figure 5 included velocity data to present raw information. Building on your insightful recommendation, we have incorporated tide information into Figure 5 to illustrate velocity variations across spring-neap tidal cycles. To provide a more comprehensive overview, we have relocated the raw velocity data to Figure 7. Figure 7 now encompasses tide, raw velocity, and residual flow data, excluding SSC data. Consequently, Figure 5 exclusively features CTD data. We sincerely appreciate your feedback, and we believe that these changes significantly enhance the clarity and informativeness of the figures.

- I understand that the study will have to be limited to using the few available data, but the scarcity of data must be assumed and included in the Conclusions as a weakness of this study. It should also be emphasized that it is important (and should also be included) to deepen the analyses carried out with a more substantial set of data (no less than two to three full years).

We acknowledge the reviewer's point regarding the limitation of available data. Based on our results, we are working on a research proposal and hopeful to obtain a new set of data and analyze the data to understand the mechanisms for flow circulation and sediment transport in a couple of years. We have revised the Conclusions section to explicitly highlight the scarcity of data as a weakness in this study. The revised last sentence now reads:

[Lines 547-549] “We recommend further research to collect a new set of flow and Suspended Sediment Concentration (SSC) data, as well as to investigate the mechanisms governing flow circulation and sediment transport along the KCC and YSWC.”