Can Sea Surface Waves Be Simulated by Numerical Wave Models Using the Fusion Data from Remote-Sensed Winds?
Round 1
Reviewer 1 Report
This article focuses on the observation of sea surface dynamics using remote sensing data.. The reviewer has the following concerns that should be addressed to improve the quality of the paper, and reconsider after major revision:
1 Abstract and Conclusion sections need further simplification to highlight the issues addressed and methods proposed in this manuscript. For the abstract, the first sentence should focus on the XXXX issue and the XXX research conducted.
2 In the Introduction section, after discussing the current research progress, this manuscript should emphasize the research content and main contributions. Particularly, the research contributions should be presented systematically, with a detailed comparison to existing studies.
3 The Cressman interpolation method used in equation (2) and its differences and advantages compared to existing interpolation methods applied to remote sensing should be explained with additional remarks.
4 Does this study assume that remote sensing data is clean and usable? If there is interference from environmental factors affecting the remote sensing data, will the data fusion processing methods differ?
5 In the Results section, there is a lack of comparison with existing references to highlight the advantages of this manuscript.
Minor editing of English language required.
Author Response
Many thanks to the reviewers for their constructive comments on our manuscript. We will respond one by one based on the suggestions.
Reply to Reviewer 1
General comment: This article focuses on the observation of sea surface dynamics using remote sensing data. The reviewer has the following concerns that should be addressed to improve the quality of the paper, and reconsider after major revision:
Reply: We are very grateful to the reviewer for comments.
Comment 1: Abstract and Conclusion sections need further simplification to highlight the issues addressed and methods proposed in this manuscript. For the abstract, the first sentence should focus on the XXXX issue and the XXX research conducted.
Reply: We appreciate this comment. In the Abstract and Conclusion sections, we have made changes according to these comments
Line 14: The purpose of our work is to investigate the performance of fusion wind from multiply remote-sensed data in forcing the numeric wave models and the experiment is conducted here.
Line 496: There are few researches on the fusion wind from remote-sensed product used in forcing the numeric wave models, i.e., WW3 and SWAN. The main purpose of our work is to classify above issue through conducting the experiment in 2019-2020.
Comment 2: In the Introduction section, after discussing the current research progress, this manuscript should emphasize the research content and main contributions. Particularly, the research contributions should be presented systematically, with a detailed comparison to existing studies.
Reply: There is few references about the fusion wind from remote-sensed product used in forcing the numeric wave models. This is the original idea to carry out our work. We give the sentence as follows.
Line 113: Till now, the modelling wave is usually forced by the result from meteorological model and the remote-sensed products have been implemented for sea surface dynamics prediction by artificial intelligence methods [34,35]. The applicability of fusion wind from radiometers and scatterometers to force numeric wave models has not reported, therefore, the experiment utilizing multiple satellites is carried out in order to classify this issue.
- Zheng, G.; Li, X.F.; Zhang, R.H.; Liu, B. Purely satellite data-driven deep learning forecast of complicated tropical instability waves. Sci. Adv. 2020, 6, eaba1482.
- Meng, L.S.; Yan, C.; Zhuang, W.; Zhang, W.W.; Yan, X.H. Reconstruction of three-dimensional temperature and salinity fields from satellite observations. J. Geophys. Res-Oceans. 2021, 12, e2021JC017605.
Comment 3: The Cressman interpolation method used in equation (2) and its differences and advantages compared to existing interpolation methods applied to remote sensing should be explained with additional remarks.
Reply: The advantage of Cressman interpolation method is interpolating data from all time points based on distance to create an interpolation result, which is better than the existing interpolation.
Line 240: The advantage of this method is that the interpolation result can be adjusted by distance under the condition of ensuring accuracy, indicating that the spatial resolution of fusion wind can be artificially selected.
Comment 4: Does this study assume that remote sensing data is clean and usable? If there is interference from environmental factors affecting the remote sensing data, will the data fusion processing methods differ?
Reply: In this study, we only used the wind data from the operationally released products. Thus, the environmental factors affecting the remote sensing data is not studied. However, this issue is important. We add the sentence in the conclusion in order to classify this issue.
Line 522: It is necessary to figure out that the distortion caused by environmental factors (i.e., SST anomaly) should be further considered so as to improve the accuracy of fusion wind.
Comment 5: In the Results section, there is a lack of comparison with existing references to highlight the advantages of this manuscript.
Reply: We add the specific comparison between our study and the existing references.
Line 376: As reported in [32], the RMSE of SWH between the SWAN-simulated and the Jason-2 altimeter is about 0.7 m, which is worse than that in this study. However, the RMSE of SWH between the WW3-simulated and the Jason-2 altimeter is about 0.2 m. It is supposedly that this is due to the lack of matchups at extreme sea state (SWHs > 6m) in [32]. Therefore, we think the fusion wind speed from radiometers and scatterometers is suitable to predict the waves from numeric wave models in near real-time, which does not rely on the results from meteorological models.
Comment 6: Minor editing of English language required.
Reply: The manuscript will be copy English editing from MDPI.
Reviewer 2 Report
General comment: The main content of this paper is to merge ASCAT scatterometer data, HY-2B scatterometer data, and wind data measured by WindSAT. The merged wind field results are then compared and analyzed with NDBC buoys, showing high correlation and relatively low root mean square error. Additionally, the paper uses the merged wind field results as the driving wind field in the third-generation wave numerical models WAVEWATCH-III and SWAN for wave simulation. The simulated results are compared with ERA-5 SWH data. The findings reveal that using the merged wind field as the driving wind field yields satisfactory simulation results. Furthermore, the article examines the difference between the merged altimetry data and the simulated wave results in different seasons, analyzing their impact in different sea areas. The research direction of this paper is relatively novel, utilizing a large amount of remote sensing data as fusion sources. The overall results of the article are satisfactory, providing a suitable approach for further improving the fusion of global wind fields using remote sensing data. However, some content in the article still needs further optimization and modification. Specific suggestions are as follows:
Comment 1: Page 2, line 53, as is widely known, there are currently three types of satellite data available for scatterometers (ASCAT). Please specify in the paragraph which type of data is being used.
Comment 2: Page 5, line 153, 'The cooperative satellite Jason-3 was launched in 2016 by international agencies'. Please write down the specific research institution names of Jason-3 in the manuscript.
Comment 3: Page 7, line 254, 'National Data Buoy Center (NDBC) buoys'. When it first appears in the paper, the full name is used, and the remaining parts are abbreviated, please make modifications here.
Comment 4: Page 5, line 178, 'the NDBC buoys in the East Pacific Ocean and Gulf of Mexico were collected for the year 2020', ' the year 2020 ', should be changed to ' the year of 2020 '.
Comment 5: Page 6, line 195, 'applied for multiple remote-sensed product fusion' should be modified as 'applied for multiple remote-sensed products fusion' .
Comment 6: Page7, lines 244-247, 'Here, 0.125 gridded fusion winds at intervals of 12 hours and daily average Copernicus Marine Environment Monitoring Service (CMEMS) sea currents and sea levels with a spatial resolution of 0.08 grid were treated as the forcing fields'. Please explain why HYcom sea currents and sea levels are not used as the driving fields for the numerical wave model, and this explanation does not need to be added to the manuscript.
Comment 7: Page 9, lines 281-282, 'were fused using the above interpolation method' , there is a Syntax error in this sentence pattern, which should be modified to 'were fused by using the above interpolation method'.
Comment 8: Page 6, Line 197, please unify the punctuation mark at the end of the formula.
Comment 9: Page 6, line 214, the word 'and' after calculating the RMSE formula can be omitted.
Comment 10: Page 14, line 394 & Page 15, line 397, the word 'TC' should be modified to 'TCs' .
Comment 11: Page 12, Figures 10&11, in the comparison results of the two data types in the article, there is a significant difference in the amount of data between NDBC and era-5 compared to Swan simulation results. Please provide a reasonable explanation.
Comment 12: Page 12, Figures 10&11, in the comparison results of the two data types in the article, there is a significant difference in the amount of data between NDBC and ERA-5 compared to SWAN simulation results. Please provide a reasonable explanation. And this explanation does not need to be added to the manuscript.
Comment 13: Page 14, line 377, 'which could be further improved using more products from other scatterometers onboard satellites'. There are certain issues with the expression of the sentence structure in this sentence. Please make appropriate modifications.
Comment 14: Page 13, line 351, 'We determined that this was likely caused by the extreme waves induced by the strong winds of the cyclonic season'. In this sentence, 'that' should be followed directly by 'was', and the redundant' this' should be deleted and modified.
Comment 15: Page 13, line 351, 'We determined that this was likely caused by the extreme waves induced by the strong winds of the cyclonic season'. In this sentence, 'that' should be followed directly by 'was', and the redundant 'this' should be deleted and modified.
Comment 16: 'fusion wind' has appeared many times in the paper, but please pay attention to the singular and plural forms everywhere and make appropriate modifications according to the entire text.
Comment 17: Figure 13(d), please explain why there are relatively more blank areas in this figure compared to (a), (b), and (c) of Figure 13.
Comments for author File: 
Comments.pdf
1. It is recommended that long and complicated sentences be divided into two sentences for better presentation.
2. Punctuation in the manuscript should be applied more accurately.
Author Response
Many thanks to the reviewers for their constructive comments on our manuscript. We will respond one by one based on the suggestions.
Reply to Reviewer 2
General comment: The main content of this paper is to merge ASCAT scatterometer data, HY-2B scatterometer data, and wind data measured by WindSAT. The merged wind field results are then compared and analyzed with NDBC buoys, showing high
correlation and relatively low root mean square error. Additionally, the paper uses the
merged wind field results as the driving wind field in the third-generation wave numerical models WAVEWATCH-III and SWAN for wave simulation. The simulated results are compared with ERA-5 SWH data. The findings reveal that using the merged wind field as the driving wind field yields satisfactory simulation results. Furthermore, the article examines the difference between the merged altimetry data and the simulated wave results in different seasons, analyzing their impact in different
sea areas. The research direction of this paper is relatively novel, utilizing a large amount of remote sensing data as fusion sources. The overall results of the article are satisfactory, providing a suitable approach for further improving the fusion of global wind fields using remote sensing data. However, some content in the article still needs
further optimization and modification.
Reply: Many thanks to the reviewers for their constructive comments on our manuscript. We will respond one by one based on these comments.
Comment 1: Page 2, line 53, as is widely known, there are currently three types of satellite data available forscatterometers (ASCAT). Please specify in the paragraph which type of data is being used.
Reply: We add ‘onboard the Metop-A/B/C’ after ‘advanced scatterometers (ASCAT)’ in the manuscript.
Comment 2: Page 5, line 153, 'The cooperative satellite Jason-3 was launched in 2016 by international agencies'.Please write down the specific research institution names of Jason-3 in the manuscript.
Reply: We have added '(NOAA, CNES, and EUMETSAT)' to line 155 of the manuscript.
Comment 3: Page 7, line 254, 'National Data Buoy Center (NDBC) buoys'. When it first appears in the paper, thefull name is used, and the remaining parts are abbreviated, please make modifications here.
Reply: By carefully reviewing the article, we made a change in line 258 of the manuscript to change ' National DataBuoy Center (NDBC) buoys ' to ' NDBC buoys'
Comment 4: Page 5, line 178, 'the NDBC buoys in the East Pacific Ocean and Gulf of Mexico were collected forthe year 2020', ' the year 2020 ', should be changed to ' the year of 2020 '.
Reply: We changed 'the year 2020' to 'the year of 2020' in the manuscript line 180.
Comment 5: Page 6, line 195, 'applied for multiple remote-sensed product fusion' should be modified as 'appliedfor multiple remote-sensed products fusion'.
Reply: We modified it in the revised manuscript.
Comment 6: Page7, lines 244-247, 'Here, 0.125 gridded fusion winds at intervals of 12 hours and daily average Copernicus Marine Environment Monitoring Service (CMEMS) sea currents and sea levels with a spatialresolution of 0.08 grid were treated as the forcing fields'. Please explain why HYCOM sea currents and sea levels are not used as the driving fields for the numerical wave model, and this explanation does not need to be added to themanuscript.
Reply: The HYCOM data was not used in the modelling, because the temporal resolution of the fusion wind was 12 hours, which was highly consistent with the resolution of the CMEMS data, so we chose the CMEMS data to obtain better results.
Comment 7: Page 9, lines 281-282, 'were fused using the above interpolation method', there is a Syntax error in thissentence pattern, which should be modified to 'were fused by using the above interpolation method'.
Reply: We modify ' were fused using the above interpolation method ' to ' were fused by using the above interpolationmethod ' in the manuscript.
Comment 8: Page 6, Line 197, please unify the punctuation mark at the end of the formula.
Reply: We have adjusted the punctuation mark after equation (2).
Comment 9: Page 6, line 214, the word 'and' after calculating the RMSE formula can be omitted.
Reply: We remove the 'and' after Equation (4) in the manuscript.
Comment 10: Page 14, line 394 & Page 15, line 397, the word ‘TC’ should be modified to 'TCs' .
Reply: We modified it in the revised manuscript.
Comment 11: Page 12, Figures 10&11, in the comparison results of the two data types in the article, there is asignificant difference in the amount of data between NDBC and era-5 compared to Swan simulation results. Pleaseprovide a reasonable explanation.
Reply: Since NDBC buoys data are single-point measurements, the amount of matched data is relatively small compared to the wave model SWAN and WW3 are regional data.
Comment 12: Page 12, Figures 10&11, in the comparison results of the two data types in the article, there is asignificant difference in the amount of data between NDBC and ERA-5 compared to SWAN simulation results. Please provide a reasonable explanation. And this explanation does not need to be added to the manuscript.
Reply: NDBC buoys data has a relatively small number of matches relative to wave models simulation data.
Comment 13: Page 14, line 377, 'which could be further improved using more products from other scatterometersonboard satellites'. There are certain issues with the expression of the sentence structure in this sentence. Pleasemake appropriate modifications.
Reply: We modified this sentence in the manuscript.
Comment 14: Page 13, line 351, 'We determined that this was likely caused by the extreme waves induced by thestrong winds of the cyclonic season'. In this sentence, 'that' should be followed directly by 'was', and the redundant' this' should be deleted and modified.
Reply: We modified it in the revised manuscript.
Comment 15: Page 13, line 351, 'We determined that this was likely caused by the extreme waves induced by thestrong winds of the cyclonic season'. In this sentence, 'that' should be followed directly by 'was', and the redundant'this' should be deleted and modified.
Reply: This comment is addressed in the revision.
Comment 16: 'fusion wind' has appeared many times in the paper, but please pay attention to the singular andplural forms everywhere and make appropriate modifications according to the entire text.
Reply: We have adjusted the singular and plural numbers of 'fusion wind' throughout the article.
Comment 17: Figure 13(d), please explain why there are relatively more blank areas in this figure compared to (a), (b), and (c) of Figure 13.
Reply: Because the measurements from Jason-3 altimeter are only used here, leading to obvious gaps in Figure 13 (d), which can be compensated for by more data in the future.
Comment 18: It is recommended that long and complicated sentences be divided into two sentences for better presentation.
Reply: We revise the manuscript throughout.
Comment 19: Punctuation in the manuscript should be applied more accurately.
Reply: The manuscript will be copy English editing from MDPI.
Round 2
Reviewer 1 Report
The manuscript has been improved based on suggestions and can be published.
