Mapping Kinetic Energy Hotspots in the Persian Gulf and Oman Sea Using Surface Current Derived by Geodetic Observations and Data Assimilation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

 

This manuscript proposes a method to calculate total surface current (TSC) by combining wind-induced Ekman current with geostrophic current derived from satellite altimeter data. Then, the TSC dataset is assimilated using in situ data and validated against ADCP data. The results show that the assimilated dataset has higher accuracy. Finally, using the assimilated dataset, the distribution of surface kinetic energy is computed, identifying six regions with the high potential for energy extraction. I think there are several parts of the manuscript that need to be revised:

1.     In Abstract, the improvement of data after assimilation needs to be described clearly (Line 21). What has improved, the amplitude of TSC? Or accuracy?

2.     The Introduction section is too lengthy (suggest adding a description of other methods for calculating ocean currents) and overly segmented (10 natural paragraphs). It is advisable to streamline the wording.

3.     The data description section lacks essential descriptions such as temporal and spatial resolution of the data. It is recommended to include relevant descriptions.

4.     In 2.2, Estimation TSC section, there is inconsistency in the symbols used for latitude descriptions (Line 160, 161).

5.     There are four different styles used to represent latitude and longitude axes in the figures of this manuscript. Please standardize them (Figures 2-7).

6.     Figure 4(a) lacks a title. Please add one.

7.     The content from Line 303-311 and Line 312-320 of the manuscript is very similar. But the last sentences of the two paragraphs are contradictory: one states "4 to 15", while the other states "3 to 15". Please review and carefully check the manuscript.

8.     Suggest optimizing the description of energy units in Table 4 (m2/s2 to m²/s²).

Comments on the Quality of English Language

English is fine.

Author Response

We would like to express our sincere gratitude for your insightful comments and thorough review of our manuscript, which has significantly enhanced its quality and clarity. Below, we have provided our detailed responses to each point raised by the reviewer:

Reviewer #1 Comments:

This manuscript proposes a method to calculate the total surface current (TSC) by combining wind-induced Ekman currents with geostrophic currents derived from satellite altimeter data. The TSC dataset is then assimilated using in situ data and validated against ADCP data, demonstrating improved accuracy. Finally, the distribution of surface kinetic energy is computed using the assimilated dataset, identifying six regions with high potential for energy extraction. I believe several parts of the manuscript require revision:

• Comment #1: In the Abstract, the improvement of data following assimilation needs to be clearly described (Line 21). Specifically, what aspect has been improved: the amplitude of TSC or accuracy?

Response #1: Thank you for your comment. We have clarified this in the manuscript text (Lines 21-22).

• Comment #2: The Introduction section is too lengthy and overly segmented (10 natural paragraphs). It is recommended to streamline the wording and include a description of other methods for calculating ocean currents.

Response #2: Thank you for your suggestion. We have revised and streamlined this section in the manuscript (Lines 30-88).

• Comment #3: The data description section lacks essential details such as the temporal and spatial resolution of the data. It is recommended to include these descriptions.

Response #3: Thank you for your comment. We have added the relevant descriptions in the manuscript (Lines 112,113,115 and 116) and made additional modifications to this section based on feedback from other reviewers.

• Comment #4: In section 2.2, Estimation of TSC, there is inconsistency in the symbols used for latitude descriptions (Lines 160, 161).

Response #4: Thank you for pointing this out. We have corrected the inconsistencies in the manuscript (Line 198).

• Comment #5: There are four different styles used to represent latitude and longitude axes in the figures of this manuscript. Please standardize them (Figures 2-7).

Response #5: Thank you for your observation. We have standardized the representation in the manuscript (Lines: 295, 317, 361, 392, 397, 432).

• Comment #6: Figure 4(a) lacks a title. Please add one.

Response #6: Thank you for your attention to detail. We have added the title in the manuscript (Line 361).

• Comment #7: The content in Lines 303-311 and Lines 312-320 of the manuscript is very similar, but the final sentences of the two paragraphs are contradictory: one states, "4 to 15," while the other states "3 to 15." Please review and carefully check the manuscript.

Response #7: Thank you for your careful review. We have corrected this discrepancy in the manuscript (Line 415).

• Comment #8: It is suggested to optimize the description of energy units in Table 4 (m²/s²).

Response #8: Thank you for your suggestion. We have revised the unit descriptions in the manuscript (Line 476).

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

In this paper the authors use a combine geostrophic currents, derived from dynamic topography, with estimates of Ekman surface currents to obtain monthly current data for the Persian Gulf and Oman Sea.  This is used to highlight areas of high kinetic energy, which the authors suggest are suitable for renewable energy schemes.  While the paper is clearly organised, and the results mostly presented clearly, there are some fundamental problems with the work and presentation that need addressing.

1 While it is reasonable for some details to be referenced from earlier work you need to explain much more about how the dynamic topography is obtained and any limitations or approximations in this data source.

2 Similarly you need to explain clearly how the NOAA estimates of Ekman surface currents are made, and any limitations and biases with these.

3 More detail of the assimilation process and its effect are needed.  Show more clearly how the estimates change with the assimilation, quantify this change more clearly, identify and discuss any systematic biases in the adjustments.

4 The currents produced are effectively monthly mean currents (aren't they) but much of the kinetic energy may be in more transient parts of the flow, especially for the Ekman surface current component.

5 The biggest problem is the failure to say anything about tides.  Tidal energy is the most likely source of renewable energy from moving sea water, and makes the most significant contribution to high energy flows including in some parts of the study area. This undermines the central reasoning behind the paper of identifying the most promising locations for renewable energy schemes.

The paper in its current form is not suitable for publication, and I think would need to be significantly refocussed and rewritten to address these shortcomings

Author Response

We would like to express our sincere appreciation for your insightful comments and thorough review of our manuscript. Your feedback has greatly contributed to enhancing the clarity and quality of the paper. Below, we provide our detailed responses to the points you raised:

Reviewer #2 Comments:

In this paper, the authors combine geostrophic currents, derived from dynamic topography, with estimates of Ekman surface currents to produce monthly current data for the Persian Gulf and Oman Sea. This data is used to identify areas of high kinetic energy, which the authors suggest are suitable for renewable energy schemes. While the paper is well-organized and the results are generally clear, there are some fundamental issues with the work and its presentation that need to be addressed.

• Comment #1: While it is reasonable to reference some details from earlier work, you need to provide a more thorough explanation of how the dynamic topography is obtained, including any limitations or approximations associated with this data source.

Response #1: Thank you for your comment. We have fully addressed this concern in the revised manuscript, providing detailed explanations in Section 2.1 (Data Description) (Lines 90-114).

• Comment #2: Similarly, you need to clearly explain how the NOAA estimates of Ekman surface currents are derived, including any limitations and biases associated with these estimates.

Response #2: Thank you for your comment. We have included a comprehensive explanation in Section 2.1 (Data Description) of the revised manuscript (Lines 115-139).

• Comment #3: More detail is needed regarding the assimilation process and its effects. Please provide clearer evidence of how the estimates change with assimilation, quantify this change more precisely, and identify and discuss any systematic biases in the adjustments.

Response #3: Thank you for your valuable comment. We have thoroughly covered these aspects in Section 2.1 (Data Description) (Lines 90-153), Section 2.2.2 (Assimilation Using the 3DVAR Method) (Lines 205-210, 228-249), Section 3 (Results) (Lines 368-382), and Section 4 (Discussion) (Lines 478-486) of the revised manuscript.

• Comment #4: The currents produced are effectively monthly mean currents, but much of the kinetic energy may reside in more transient parts of the flow, particularly in the Ekman surface current component.

Response #4: Thank you for your insightful comment. We agree that transient parts of the flow, such as those seen in Ekman currents, can significantly influence kinetic energy estimates. However, the objective of this study is to identify locations suitable for harnessing kinetic energy from the permanent (steady-state) currents. While Ekman currents driven by wind forcing can fluctuate on daily to weekly timescales, averaging these currents over a monthly timescale helps to smooth out high-frequency noise and captures a more stable representation of general surface flow direction and magnitude. Similarly, while mesoscale eddies and other transient features contribute to kinetic energy, these are often localized in both space and time. The monthly mean currents still effectively characterize the large-scale, dominant circulation patterns that integrate these transient phenomena. For many oceanographic applications, including this study, monthly or seasonal timescales provide valuable insights into the non-tidal, wind- and density-driven circulation patterns. We have added a detailed explanation of this in the Discussion section (Lines: 487-499).

• Comment #5: The most significant issue is the omission of any discussion on tides. Tidal energy is a highly likely source of renewable energy from moving seawater and significantly contributes to high-energy flows, including in parts of the study area. This omission undermines the central premise of the paper in identifying the most promising locations for renewable energy schemes.

Response #5: Thank you for your critical comment. We agree that tidal energy is widely recognized as one of the most promising sources of renewable energy from moving water, often surpassing the energy available from mean ocean currents. However, as mentioned in response to Comment 4, the primary goal of this study is to identify locations suitable for harnessing kinetic energy from the permanent currents within the study region. The broader topic of kinetic energy generation from tidal potentials, including tidal waves and tidal currents, has been addressed in various other studies and could be analyzed separately. In this paper, the focus is on the permanent currents, but we have now included multiple explanations and references to the significance of tidal energy in the Introduction (Lines: 37-39), Results (Lines: 449-468), and Discussion (Lines:506-509 ) and sections of the revised manuscript.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

 

 

Revision of the scientific paper: Mapping Kinetic Energy Hotspots in the Persian Gulf and
Oman Sea Using Surface Current Derived by Geodetic Observations and Data Assimilation


The paper as such seems to be well developed, the abstract gives the necessary and fair information of the paper. The introduction seems to me a bit long, it seems to me that it could be summarised a bit (a little is more). But the justifications made in the introduction seem to me to justify the work, both at the scientific and applied level for society. Both results and conclusions seem to me to be correct. However, I have several comments or observations on section 2.1 that I think need to be considered. First I consider the minor revisions:

Minor revisions:
1.-Although the work is based on the previous work Pirooznia, et al.(2024) that one has to read to understand much of what is proposed. It would be good to make a more detailed description of the data used, such as what spatial and temporal resolution is being used. Secondly, it is mentioned that Ekman surface current from NOAA is used, but I did not find the address where these data could be found. That is why I think it is important to include it for the benefit of the reader.

Major revisions:

1.- In the paper they mention that there are several ADCPs installed in the region and that they were used to validate the data. First of all, it would be good to include the position of the ADCPs in Figure 2.
2.- To give more credibility to the work, include the ellipses of variability and average vector of the ADCPs and the velocities that you are generating, detail and explain if there are discrepancies in the orientation, etc.
3.- It seems to me that an important region is the Hormus Strait where it seems to me that you should have at least 4 points of the grid. However, the dynamics in this region must have a strong ageostrophic component that I don't think can be explained only with geostrophic velocities and Ekman currents. Please explain or elaborate further in the text. In addition, it seems to me that it could be important to consider the effect of the tide in this region.
4.- Similarly, several papers mention that care must be taken when using near-shore altimetry, e.g. Carrillo et. al. 2001 and Palma et al. 2022. Describe what considerations they used to use nearshore geostrophy data.

 

5.- It seems that a section called discussion is necessary for this paper, as the Strait of Hormuz seems to have a much more complex dynamics that cannot be explained by considering only geostrophy and ekman surface current. Consider what other components contribute to the dynamics, how they can be analysed, etc. All, considering the energetic implications that justify their work.

I consider that these 5 points can help the reader, whether a student or a researcher who wishes to apply this to his or her own area of study. And it will make the work more convincing.

 

Pirooznia, M., Voosoghi, B., Poreh, D., & Amini, A. (2024). Integrating Hydrography Observations and Geodetic Data for Enhanced Dynamic Topography Estimation. Remote Sensing, 16(3), 527.

 

Carrillo, L., & Palacios-Hernández, E. (2002). Seasonal evolution of the geostrophic circulation in the northern Gulf of California. Estuarine, Coastal and Shelf Science, 54(2), 157-173.

 

Palma-Lara, D., Carrillo, L., Trasviña-Castro, A., Reyes-Mendoza, O., & Valle-Rodríguez, J. (2023). Analysis of coastal altimetry in the Mexican Caribbean. Advances in Space Research, 71(1), 964-974.

 

Author Response

We sincerely appreciate your thorough review and insightful comments on our manuscript. Your suggestions have greatly contributed to improving the clarity and robustness of our work. Below, we provide our detailed responses to each of the points you raised:

Reviewer #3 Comments:

The paper appears to be well-developed, with the abstract providing the necessary and accurate information. While the introduction is somewhat lengthy, it justifies the work both scientifically and in terms of its societal applications. The results and conclusions also seem appropriate. However, I have several comments or observations on Section 2.1 that I believe need to be addressed. I have categorized these into minor and major revisions.

Minor Revisions:

• Comment #1: Although the work builds on previous research by Pirooznia et al. (2024), which is essential for understanding much of the proposed methodology, it would be beneficial to provide a more detailed description of the data used, including the spatial and temporal resolutions. Additionally, the manuscript mentions the use of Ekman surface current data from NOAA, but the source of these data is not provided. Including this information would greatly benefit the reader.

Response #1: Thank you for your suggestion. We have expanded the explanations in Section 2.1 (Data Description) of the revised manuscript to include a more detailed description of the data, including their spatial and temporal resolutions, as well as the source of the NOAA Ekman surface current data (Lines 115-164).

Major Revisions:

• Comment #1: The paper mentions the use of several ADCPs installed in the region for data validation. It would be helpful to include the locations of these ADCPs in Figure 2.

Response #1: Thank you for this suggestion. We have added the locations of the ADCPs to Figure 2 in the revised manuscript (Line 295).

• Comment #2: To enhance the credibility of the work, please include ellipses of variability and the average vector for the ADCPs, as well as the velocities generated by your model. Additionally, detail and explain any discrepancies in orientation or other aspects.

Response #2: Thank you for your comment. We have included a comprehensive explanation in the Results section, detailing the differences between the model before and after data assimilation, as well as the ADCP current measurements. This includes the ellipses of variability and average vectors (Lines: 368-382).

• Comment #3: The Strait of Hormuz is an important region where it appears that you should have at least four grid points. The dynamics in this region likely have a strong ageostrophic component that may not be fully explained by geostrophic velocities and Ekman currents alone. Please elaborate on this in the text. Additionally, the tidal effects in this region may also be significant and should be considered.

Response #3: Thank you for highlighting the importance of the Strait of Hormuz. We have emphasized the significance of this region in the revised manuscript and added additional information and analysis related to its dynamics in the Results (Lines:322-333, 342-344, 446-448, 458-466), Discussion (Lines: 498-500) and Conclusion (Lines:544, 550-552) sections. While we acknowledge the complexity of the dynamics in this region, including potential geostrophic components and tidal effects, our study focuses on identifying locations suitable for harnessing kinetic energy from permanent (steady-state) surface currents. However, we have included a discussion of these additional factors and their potential impact in the revised manuscript.

• Comment #4: Several papers, such as those by Carrillo et al. (2001) and Palma et al. (2022), suggest exercising caution when using nearshore altimetry. Please describe the considerations you used when incorporating nearshore geostrophic data in your study.

Response #4: Thank you for bringing this to our attention. We have added a detailed description of the considerations related to using nearshore geostrophic data in Section 2.1 (Data Description) (Lines: 94-96, 100-102) of the revised manuscript.

• Comment #5: It seems that a separate discussion section is necessary for this paper, particularly to address the complex dynamics in the Strait of Hormuz, which may not be fully explained by geostrophic and Ekman surface currents alone. Please consider what other components contribute to these dynamics, how they might be analyzed, and their implications for energy extraction.

Response #5: Thank you for your suggestion. We have added a new Discussion section to the manuscript, which includes additional analyses and results for the Strait of Hormuz region. While our study's primary objective is to identify locations suitable for utilizing kinetic energy from the Sea by determining the permanent (steady-state) surface currents (Total Surface Current = Geostrophic + Ekman) in the study area, we acknowledge that other factors, such as tidal energy, are important. These broader topics have been addressed in the revised manuscript to provide a more comprehensive context for our findings (Lines: 330-333, 449-468, 477-504).

We believe that addressing these five points will enhance the manuscript's clarity and make it more useful for readers, whether they are students or researchers looking to apply these findings to their own areas of study.

• Pirooznia, M., Voosoghi, B., Poreh, D., & Amini, A. (2024). Integrating Hydrography Observations and Geodetic Data for Enhanced Dynamic Topography Estimation. Remote Sensing, 16(3), 527.
• Carrillo, L., & Palacios-Hernández, E. (2002). Seasonal evolution of the geostrophic circulation in the northern Gulf of California. Estuarine, Coastal and Shelf Science, 54(2), 157-173.
• Palma-Lara, D., Carrillo, L., Trasviña-Castro, A., Reyes-Mendoza, O., & Valle-Rodríguez, J. (2023). Analysis of coastal altimetry in the Mexican Caribbean. Advances in Space Research, 71(1), 964-974.

Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

The authors identify kinetic energy hotspots in the Persian Gulf and Oman Sea using surface currents derived from geodetic observations and data assimilation. It is necessary to do the research before utilizing the current energy.

This should be the main contribution. However, the significance of the academic value seems trivial. The 3DVAR improves the accuracy of the current vector. However, it is not the innovation. If it is published in the journal, the innovation of the work on academic contribution should be made clearer. Besides, the spatial resolution of sea currents should be made clear.

Comments on the Quality of English Language

Need to be improved.

Author Response

We sincerely appreciate your thoughtful comments and careful review of our manuscript. Your feedback has been instrumental in refining and enhancing the clarity and significance of our work. Below, we provide our detailed responses to the points you raised:

Reviewer #4 Comments:

The authors identify kinetic energy hotspots in the Persian Gulf and Oman Sea using surface currents derived from geodetic observations and data assimilation. Research is necessary before utilizing current energy.

• Comment #1: This should be the main contribution. However, the academic significance appears trivial. While the 3DVAR method improves the accuracy of the current vector, it does not constitute an innovation. If this work is to be published in a journal, the academic contributions should be more clearly defined. Additionally, the spatial resolution of sea currents should be clarified.

Response #1: Thank you for your insightful comment. We have taken steps to more clearly articulate the innovations and academic contributions of our work in the revised manuscript. Specifically, we have emphasized the novel methodology for determining kinetic energy from permanent surface currents. Detailed explanations have been provided regarding the innovations associated with our data assimilation process and analyses. We have also clarified the spatial and temporal resolutions of the data and surface current estimates in Section 2.1 (Lines 112,113,115 and 116). Furthermore, additional challenges and considerations have been incorporated into the Discussion section. It is important to note that this study is the first in the region to use a data-driven approach to identify areas suitable for marine energy extraction based on permanent currents derived from geodetic observations.

To briefly summarize the key innovations and contributions of this study:

1. Estimation of Total Surface Current (TSC): This study presents a novel approach to estimating TSC by integrating data from geodetic observations (for geostrophic currents) with NOAA's Ekman current data.
2. Data Assimilation Using 3DVAR: To improve the accuracy of TSC estimates, we employed the 3DVAR data assimilation method, incorporating local current meter observations. This approach resulted in an improvement of 4-15 cm/s in the precision of the calculated TSC by appropriately considering the variance-covariance matrices (matrices R and B) in the data assimilation process.
3. Identification of Locations for Marine Kinetic Energy Extraction: Using the assimilated TSC data, we assessed the kinetic energy potential and identified six regions (Khowre Musa, Kangan, Strait of Hormuz, Mangoli, Jask, and Pasabandar) with the highest promise for marine kinetic energy extraction.
4. Addressing Challenges in Data and Modeling: This study addresses several key challenges, including the limitations of satellite data and global models, the impact of transient surface currents, and the necessity for local data calibration in numerical models such as CMEMS.

We believe these enhancements significantly strengthen the academic value and innovation of our work, making the manuscript more compelling for publication.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

While I'm not completely convinced that the approach described here identifies the best places for renewable (kinetic) energy sites, the authors have considerably improved many aspects of the manuscript, including useful material about tidal flows/energy, so that the paper is now suitable for publication.

Author Response

Reviewer #2 Comments:

Comment: While I'm not completely convinced that the approach described here identifies the best places for renewable (kinetic) energy sites, the authors have considerably improved many aspects of the manuscript, including useful material about tidal flows/energy, so the paper is now suitable for publication.

Response: Thank you for your feedback and for acknowledging the improvements made to the manuscript.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

 

 

Thank you very much for taking into account the comments and suggestions. After reviewing the work I have the following recommendations. First as minor revision:

1. Include what is meant by GRACE “Gravity Recovery and Climate Experiment ” (line 97), although it is well described in the mentioned paper. In this paper it is not. In my opinion, this seems to be an editorial error, since they do mention VCE.
2. The figures seem to be made in matlab, so it seems to me that for the good of the work they can use the same colormap, considering figure 4.
3. About figure 4, you can use streamslice or streamline instead of quiver, if the part that you want to highlight in d) (purple colors) cannot be seen by the excess of vectors.
4. In figure 3 and 7 fix color axis, it cannot be that in a has a colorbar different from the other, it confuses.

Regarding the CMEMS model data, I think it should be included as major corrections:
1.- I don't understand why they used monthly data and not daily, since they are also available, maybe comparing the data will change something (although I don't think much but it is a fairer comparison). This CMEMS model which is based on NEMO uses fixed levels so it is not the right model for comparison. If you want to compare it, it is much more correct to use ROMS or Hycom taking into account that it uses sigma or hybrid coordinates that adapt to the topography. I must emphasize that the CMEMS approach is more for open ocean than for near shore data, so it is included in the results section between lines 416 and 423 may have some bias. Therefore, I consider the importance of mentioning which layer was used, if that layer being the most superficial includes the effect of wind, etc.. I mention this because if I were to ulitize a model in the study region I would first consider CROCO, ROMS before NEMO, since the bathymetric region seems to be quite complex. Therefore, I consider to rewrite everything corresponding to the CMEMS model.

 

 

 

Author Response

Thank you very much for taking into account the comments and suggestions. After reviewing the work, I have the following recommendations. First as minor revision:

Reviewer #3 Comments:

The paper appears to be well-developed, with the abstract providing the necessary and accurate information. While the introduction is somewhat lengthy, it justifies the work both scientifically and in terms of its societal applications. The results and conclusions also seem appropriate. However, I have several comments or observations on Section 2.1 that I believe need to be addressed. I have categorized these into minor and major revisions.

Minor Revisions:

• Comment #1: Include what is meant by GRACE “Gravity Recovery and Climate Experiment” (line 97), although it is well described in the mentioned paper. In this paper it is not. In my opinion, this seems to be an editorial error, since they do mention VCE.
• Response #1: Thanks for your comment. It was corrected.
• Comment #2: The figures seem to be made in MATLAB, so it seems to me that for the good of the work they can use the same colormap, considering figure 4.
• Response #2: Thanks for your comment. The colormap related to Figure 4 was tested in the other figures; however, unfortunately, when this colormap is used, the variations and patterns present in the other Figures do not display well. For instance, an example of the colormap change is provided for Figures 3 of manuscript in the bellow (Figure 1).

An important point here is that several colormaps were tested for better visualization of the all figures, and the provided colormap performed better than the others.

Initial colormap	Proposed colormap
Figure 3 (a)	Figure 3 (a)
Figure 3 (b)	Figure 3 (b)

Figure 1. Testing Colormap

• Comment #3: About figure 4, you can use streamslice or streamline instead of quiver, if the part that you want to highlight in d) (purple colors) cannot be seen by the excess of vectors.
• Response #3: Thanks for your comment. It was corrected.
• Comment #4:  In figure 3 and 7 fix color axis, it cannot be that in a has a color bar different from the other, it confuses.
• Response #4: Thank you for comment. It was corrected.

Major Revisions:

• Comment #1:  I don't understand why they used monthly data and not daily, since they are also available, maybe comparing the data will change something (although I don't think much but it is a fairer comparison). This CMEMS model which is based on NEMO uses fixed levels so it is not the right model for comparison. If you want to compare it, it is much more correct to use ROMS or Hycom taking into account that it uses sigma or hybrid coordinates that adapt to the topography. I must emphasize that the CMEMS approach is more for open ocean than for near shore data, so it is included in the results section between lines 416 and 423 may have some bias. Therefore, I consider the importance of mentioning which layer was used, if that layer being the most superficial includes the effect of wind, etc. I mention this because if I were to utilize a model in the study region, I would first consider CROCO, ROMS before NEMO, since the bathymetric region seems to be quite complex. Therefore, I consider to rewrite everything corresponding to the CMEMS model.
• Response #1: Thanks for your comment.

As stated in the manuscript, this study aims to introduce a data-driven approach for modeling steady currents and identifying locations suitable for harnessing marine energy from these permanent currents. To achieve this (modeling permanent current), we focused on monthly data. Moreover, using monthly data allows for a clearer understanding of trends and patterns that may be masked in daily data due to short-term fluctuations and noise. This approach helps to emphasize significant long-term changes, which is particularly important for evaluating the potential for renewable energy

Regarding the CMEMS model, it's true that it is a relatively simple model. However, it's important to clarify that our goal was to validate our proposed data-driven model using local data with the aid of another model. We chose the CMEMS model because it offers readily available outputs, and its data is easily accessible, avoiding the complexities associated with implementing more intricate numerical oceanographic models like ROMS. If our objective had been to model currents instantaneously while taking into account all factors affecting ocean currents—an endeavor beyond the scope of this study and a topic worthy of its own exploration—we would have certainly opted for more advanced models such as MITGCM or others. Furthermore, the CMEMS model serves as a solid framework for large-scale oceanographic studies. Its use in this context is well justified, especially since our focus is on broader patterns rather than highly localized phenomena. Also, this model which is recognized for its reliable data and has been utilized in various studies [1]. We believe that the outputs from the CMEMS model are sufficient for our comparative analysis, and transitioning to another model, which would require extensive preparations and introduce complexities, may not significantly improve our findings.

Considering your suggestion, the vertical layer of the CMEMS model used is detailed in Section 2.1, Lines 157-158, and further explanations regarding the use of an alternative model can be found in the discussion section on Lines 507-512.

Here, in addition to the CMEMS model, the HYCOM model also is used (the use of the HYCOM model will be explored in our next study, which is part of our future research and falls outside the scope of this manuscript), this model which is much closer to our data-driven model but still needs local calibration as stated in discussion (see Figure 2 below). Thus, we believe that bringing one model (CMEMS model) into the manuscript is sufficient for validation procedure.

 

(a)	(b)
(c)	(d)

 

Figure 2. Comparison of the TSC components from the local station, the CMEMS model, the assimilated TSC, and HYCOM model at the Nakhl Taghi control station. U (a), V (b), Residual of U (c), Residual of V(d).

[1]. Bendoni, M., Fattorini, M., Taddei, S. et al. High-resolution downscaling of CMEMS oceanographic reanalysis in the area of the Tuscany Archipelago (Italy). Ocean Dynamics 72, 295–312 (2022). https://doi.org/10.1007/s10236-022-01501-3

Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

It solves all my concerns. It should be published in the journal.

Author Response

Reviewer #4 Comments:

It solves all my concerns. It should be published in the journal.

Thank you so much for your encouraging feedback

Author Response File: Author Response.docx