Satellite-Based Evaluation of Submarine Permafrost Erosion at Shallow Offshore Areas in the Laptev Sea

Round 1

Reviewer 1 Report

Please, find the document attached

Comments for author File: Comments.pdf

Author Response

The peer-reviewed article “Satellite-Based Evaluation of Submarine Permafrost Erosion at Shallow Offshore Areas in the Laptev Sea” and the results presented in it seem to be very interesting. However, there are a number of serious comments, among which we highlight the following:

1. The statement “This large area is covered by submarine permafrost with a thickness of 300-600 km [10]” is incorrect. First, this statement is based on old (2011) modeling data, which is very dependent on a limited amount of heat flow data. Currently, there are results of drilling and geophysical research (Petrov et al, 2023; Bogoyavlensky et al, 2021-2022), which indicate the absence of subaqueous permafrost on a significant part of the shelf of the seas of Eastern Siberia. New data is not presented or discussed in the article.

We fully agree with the reviewer, that the question about presence or absence of submarine permafrost in the study area should be discussed in more detail in this article. However, we do not agree with the reviewer’s opinion regarding the absence of subaqueous permafrost on a significant part of the shelf of the seas of Eastern Siberia. Below we provide the appropriate references which provide the basement for our statements.

We agree with the reviewer that until recently our understanding of the current thermal state and stability of submarine permafrost in the East Siberian Arctic seas (ESAS), was primarily based on modeling results (Soloviev et al 1987; Kim et al 1999; Delisle 2000; Romanovskii and Hubberten, 2001; Romanovskii et al 2005; Nicolsky et al., 2012). However, existence of subsea permafrost in the ESAS was documented by many studies during the last decades. For instance, in the 1970-1980 many field surveys in the Laptev Sea shelf were focused on submarine permafrost and drilled numerous boreholes at seabottom (Soloviev et al., 1987). The observed permafrost temperatures and thicknesses revealed that the upper and lower permafrost boundaries have large lateral variation. The distribution of frozen and thawed ground across the boreholes, as well as their locations were published by Fartishev (1993), Slagoda (2004) and others. A layer of frozen ground was observed in each borehole.

Regarding “old” modeling data referred in our paper, we should note that a joint recent vision of Russian – German subsea permafrost team was referred (published in the recent paper numbered [7] in the manuscript (Angepolous et al., 2020), which is focused on changes in the subsea permafrost state, but not on its absence. We also added one reference to the current paper describing modeling of ESAS subsea permafrost, which was proofed by drilling data (Shakhova et al., 2009). This paper demonstrates sufficient agreement with the observed distribution of thawed and frozen layers to suggest that the proposed mechanism of subsea permafrost destabilization is plausible.

The reviewer is absolutely right stating that an “old” modeling data are very dependent on a limited amount of thermal data. The reviewer refers to results of drilling and geophysical research (Petrov et al, 2023; Bogoyavlensky et al, 2021-2022), which “indicate the absence of subaqueous permafrost on a significant part of the shelf of the seas of Eastern Siberia”. However, Bogoyavlensky et al. used MAGE geophysical data that is based on analysis of refracted waves velocities, which were never been validated by drilling. The study of Petrov et al (2023) reported only one drilling site DL-1, which is located near DeLong Arc active volcanoes province with high geothermal flux supposed to be there. This drilling demonstrates a wide range of  temperatures from sediment surface down to 268 meters. It was shown that during 5 days after drilling the borehole temperature decreased significantly. From geocryological point of view, we believe that much longer time is needed to reach the thermal equibalance with the drilling-heated sediment. It is a well-known effect of complete subsea permafrost melting during such parametric drilling using powerful drilling rigs. As a result, we believe that the results described in (Petrov et al, 2023; Bogoyavlensky et al, 2021-2022) could not be used to state “the absence of subaqueous permafrost on a significant part of the shelf of the seas of Eastern Siberia” due to methodological reasons.

In resume, regarding reviewer recommendation we added the following paragraph to Section 2.1 citing the most novel studies (published in 2022 and 2023): about the considered question:

 

According to recent thermodynamic sediment data and electromagnetic surveys submarine permafrost is continuous at the major part of the Laptev Sea shelf from the shoreline up to isobaths of 80–100 m [44, 45]. However, at certain shelf areas submarine permafrost is discontinuous and contains gas and gas hydrate accumulations. Submarine permafrost layer has a thickness of several hundred meters, which degrades at a rate of about 14–18 cm per year [7, 11, 46, 47].

 

Secondly, there is a serious error in this provision (a typo indicating the negligence and inattention of the authors to the text of their article) should be “300-600 m”, and not “300-600 km”.

Corrected.

 

2. The title and all provisions of the article contain the term “Submarine Permafrost Erosion”, which implies direct contact of sea water and frozen bottom sediments. In general, this is not true for the bottom of the Laptev Sea, but is true only for limited area contact zones of frozen rocks near the shore. This may also be true in very shallow areas, where in winter the ice comes into contact with the bottom and freezes together.

The authors say “In this study, we focus on areas of seafloor erosion in the Laptev Sea which correspond to offshore shoals (with depths < 10 m).” This is too much tolerance. After being flooded by the sea, the upper layer of frozen sediments on the bottom of the Laptev Sea almost everywhere has long been degraded and consists of thawed sediments ranging in thickness from several meters to several tens of meters. This has been proven by drilling a number of wells (for example, Overduin et al, 2015 and etc.). In addition, according to geophysical studies, permafrost is completely absent in a number of areas of the Laptev Sea bottom (Bogoyavlensky et al, 2021-2022).

As a result, there is no justification that the decisive factor in water turbidity is wave erosion, and not thermal abrasion, as the authors claim (“Thermal abrasion of submarine permafrost results in upward advection of suspended matter, which could reach surface layer in shallow areas.”). During a storm, turbidity of water near the coast occurs due to the influence of waves in all seas of the world, regardless of the presence or absence of permafrost.

Therefore, the use of the term “Submarine Permafrost Erosion” in the title of the article and in the main conclusions seems incorrect and/or unfounded.

Authors need to take into account the above, after which the article can be recommended for publication.

 

First, we would like to mention that the work by Overduin et al. (2015) cited by the reviewer is based on one drilling site accomplished at water depth ~6 m nearby the continental coast, which has subsea permafrost at shallow sediment horizons. This area is strongly impacted by the heating effect of the Lena River discharge. It was shown that remnants of ice complexes (submerged ice-complex is a kind of subsea permafrost) are covered by several meters of ocean sediments and are found within the ESAS (Rachold et al., 2007). According to Overduin et al. (2007), an approximately 10 m thick ice complex was also found at the depths of 50–60 m below the ground surface of the near-shore zone of the Laptev Sea. It is suggested that this ice complex was formed during the Late Sangamon and survived until the present day. This sequence of ocean regressions and transgressions results in the ground material beneath the ESAS ocean bottom having a complex structure consisting of salt-contaminated sediments, both frozen and thawed, layered with ice complexes (Rachold et al 2007, Overduin et al 2007).  The most recent data confirm that the East Siberian, Laptev and Kara shelves have unfrozen (ice-free) cryotic sediments on the top, with −1.0 to −1.8 °C negative temperatures, i.e., 0.6 оС above the freezing point. The shallow bottom sediments apparently lie over buried ice-rich permafrost, which is however absent or deepened in the shallow shelf waters impacted by the river heating effect and at water depths >100 m, where the sediment temperatures are above 0 °C (Shakhova et al., 2014, 2017; Chuvilin et al., 2022; Bukhanov et al., 2023). Finally, the presence of submarine permafrost erosion at the Vasilevskaya and Semenovskaya shoals is based on observational data obtained by the authors of this paper during the last 25 years (Dudarev et al., 2003, 2008, 2015).

 

References:

 

Alekseev, D.A., Koshurnikov, A.V., Gunar, A.Y., Balikhin, E.I., Semiletov, I.P., Shakhova, N.E., Palshin, N.A., Lobkovsky, L.I. Time-Domain Electromagnetics for Subsea Permafrost Mapping in the Arctic: The Synthetic Response Analyses and Uncertainty Estimates from Numerical Modelling Data. Geosciences 2023, 13, 144. https://doi.org/10.3390/geosciences13050144

Are, F.E. Shore face of the Arctic seas—A natural laboratory for subsea permafrost dynamics. In Permafrost; Phillips, M., Springman, S.M., Arenson, L.U., Eds.; Swets & Zeitlinger: Lisse, The Netherlands, 2003; pp. 27–32.

Bukhanov, B., Chuvilin, E.,  Zhmaev, M., N. Shakhova, N.,  Spivak, E.,  Dudarev, O.,  Osadchiev, A., Spasennykh, M., and  I. Semiletov. In situ bottom sediment temperatures in the Siberian arctic seas: Current state of subsea permafrost in the Kara Sea vs Laptev and East Siberian seas. Marine Petroleum Geology, Volume 157, November 2023, 106467

Dudarev, O.V., Charkin, A.N., Shakhova, N.E. et al. Peculiarities of the present-day morpholithogenesis on the Laptev Sea Shelf: Semenovskaya shoal (Vasema Land). Dokl. Earth Sc. 462, 510–516 (2015). https://doi.org/10.1134/S1028334X15050116

Dudarev, O.V., Charkin, A.N., Semiletov, I.P. et al. The current state of submarine island relicts on the East Siberian shelf. Dokl. Earth Sc. 419, 352–358 (2008). https://doi.org/10.1134/S1028334X08020372

Dudarev, O., Semiletov, I., Botsul, A., & Charkin, A. (2003). Modern sedimentation in the coastal cryolithozone of the Dmitry Laptev Strait. East-Siberian Sea, Pacific Geology, 22(1), 51-60.

Koshurnikov, Andrey & Tumskoy, Vladimir & Shakhova, Natalia & Sergienko, N. & Dudarev, O. & Gunar, A. & Pushkarev, Pavel & Semiletov, Igor & Koshurnikov, A.. (2016). The first ever application of electromagnetic sounding for mapping the submarine permafrost table on the Laptev Sea shelf. Doklady Earth Sciences. 469. 860-863. 10.1134/S1028334X16080110.

Nicolsky, D.; Romanovsky, V.; Romanovskii, N.; Kholodov, A.; Shakhova, N.; Semiletov, I. Modeling sub-sea permafrost in the East Siberian Arctic Shelf: The Laptev Sea region. J. Geophys. Res. 2012, 117, F03028.

Grigoriev, N.F. Mnogoletnemerzlie Porodi Primorskoy zoni Yakutii; Nauka: Moscow, Russia, 1986; 123p, [in Russian].

Shakhova N.E., Nicolsky D., and I. P. Semiletov, 2009.  On the current state of sub-sea permafrost in the East-Siberian Shelf  testing of modeling results by observational data. Transactions of Russian Academy of Sciences, Vol. 429 (5), translated in English by Springer)

Shakhova, N., Semiletov, I., Gustafsson, O., Sergienko, V., Lobkovsky, L., Dudarev, O., Tumskoy, T., Grigoriev, M., Mazurov, A., Salyuk, A., Ananiev, R., Koshurnikov, A., Kosmach, D., Charkin, A., Dmitrevsky, N., Karnaukh, V., Gunar, A., A. Meluzov, A., Chernykh, D. (2017): Current rates and mechanisms of subsea permafrost degradation in the East Siberian Arctic Shelf. Nature Communications. 8, 15872 doi: 10.1038/ncomms15872.

Shakhova N., Semiletov I., Leifer I., Sergienko V., Salyuk A., Kosmach D., Chernikh D., Stubbs Ch., Nicolsky D., Tumskoy V., and Gustafsson Ö. Ebullition and storm-induced methane release from the East Siberian Arctic Shelf // Nature Geoscience, 2014. 7, 64-70. doi: 10.1038/NGEO2007.

Shakhova, N.; Semiletov, I.; Chuvilin, E. Understanding the Permafrost–Hydrate System and Associated Methane Releases in the East Siberian Arctic Shelf. Geosciences 2019, 9, 251. https://doi.org/10.3390/geosciences9060251

Slagoda, E.A. Cryolithogenic Deposits of the Laptev Sea Coastal Lowland: Lithology and Micro-Morphology (Bykovsky Peninsula and Moustach Island); Express: Tyumen, Russia, 2004; 122p, [in Russian].

Vonk, J. E., L. Sánchez-García, B. E. van Dongen, V. Alling, D. Kosmach, A. Charkin, I. P. Semiletov, O. V. Dudarev, N. Shakhova, P. Roos, T. I. Eglinton, A. Andersson, and Ö. Gustafsson (2012), Activation of old carbon by erosion of coastal and subsea permafrost in Arctic Siberia, Nature, 489 (7414), 137-140.

Reviewer 2 Report

The study investigates coastal sediment transportation for shallow offshore areas. Laptev Sea is selected for the application. Then, the observation of daily suspended sediment discharge between 1979-2021 is assessed in the paper. Some suggestions and comments to the authors are presented below:

1. A basic flowchart of the suggested methodology should be added in the paper. Thus, the readers can easily follow the application procedures.

2. Some legends on the figures & maps should be presented better and live colours. Also, there are missing legends of the maps as Figure 2 …

3. Conclusions part can be improved in the paper. Here is presented in a general concept.

4. What is the novelty of the paper? The used traditional methods for wave parameters (as WAVEWATCH III) are explained in the paper. Supported and related studies should be strongly presented in the paper by emphasizing the novelty of the paper.

5. Literature part is looking weak. Give new and last updated examples from literature about “sediment” as

doi.org/10.1038/s43017-021-00232-1

doi.org/10.54740/ros.2022.016

 

6. Is the suggested methodology in the paper valid for all areas or is there any limitation or classification for the application?

7. As one important step of the study, the statistical characteristics of used data (e.g. daily suspended sediment data) should be presented in detail. The statistical properties as skewness, coefficient of variation, confidence intervals, distribution characteristics, min, max and median, etc. of used data should be given in a table.

8. The performance metrics part is missing in the paper. The metrics can be calculated to evaluate the application results as NSE, R-squared, RMSE, MAE, MSE, RSR (Ratio of RMSE to the standard deviation of the observations) etc. …

 

9. The resolution of the spatial maps & figures can be increased.

Check the tenses of the sentences. There are present and present perfect tenses in a paragraph. See the paragraph in the Abstract.

There are some crucial errors.

Keywords should be ordered A to Z.

 

Use passive sentences. Check the sentences started by “we”. See the Abstract …

Author Response

The study investigates coastal sediment transportation for shallow offshore areas. Laptev Sea is selected for the application. Then, the observation of daily suspended sediment discharge between 1979-2021 is assessed in the paper. Some suggestions and comments to the authors are presented below:

 

1. A basic flowchart of the suggested methodology should be added in the paper. Thus, the readers can easily follow the application procedures.

According to your recommendation, we added the related flowchart to the end of the Introduction.

 

2. Some legends on the figures & maps should be presented better and live colours. Also, there are missing legends of the maps as Figure 2 …

Many thanks for this point; we substantially improved the quality of all figures.

 

3. Conclusions part can be improved in the paper. Here is presented in a general concept.

According to your recommendation, we extended the Conclusions with a paragraph focused on the role of submarine permafrost erosion on local nutrient and carbon cycles in context of the ongoing climate change, which provides enhanced acidification and atmospheric CO₂ emission.

 

4. What is the novelty of the paper? The used traditional methods for wave parameters (as WAVEWATCH III) are explained in the paper. Supported and related studies should be strongly presented in the paper by emphasizing the novelty of the paper.
5. Literature part is looking weak. Give new and last updated examples from literature about “sediment” as

doi.org/10.1038/s43017-021-00232-1

doi.org/10.54740/ros.2022.016

Many thanks for this comment. This paper describes the first comprehensive study that addressed dynamics and variability of seafloor erosion in shallow areas in the Laptev Sea and provided the related assessments of sediment fluxes. The obtained results are of key importance for monitoring and evaluation of increasing subsea permafrost erosion in the Laptev Sea, which could be a potential and still uncounted contributor to regional CO₂ system. The related clarification was added to the text. Also, we added references to relevant papers including those recommended above to the Introduction and Methodology sections.

 

6. Is the suggested methodology in the paper valid for all areas or is there any limitation or classification for the application?

Many thanks for this point. The suggested methodology could be applied to other shoal and coastal sea areas, which experience active resuspension and erosion. The main limitation of this approach is necessity to have data pertaining to sediment concentration variability. This information was added to the Conclusions.

 

7. As one important step of the study, the statistical characteristics of used data (e.g. daily suspended sediment data) should be presented in detail. The statistical properties as skewness, coefficient of variation, confidence intervals, distribution characteristics, min, max and median, etc. of used data should be given in a table.

According to your recommendation, we provided the main statistical characteristics of daily suspended sediment flux from VS during ice-free season reconstructed for 1979-2021 in Table 1.

 

8. The performance metrics part is missing in the paper. The metrics can be calculated to evaluate the application results as NSE, R-squared, RMSE, MAE, MSE, RSR (Ratio of RMSE to the standard deviation of the observations) etc.

According to your recommendation, we provided the necessary statistical characteristics of the dependence between area of the turbid zone at VS and a 9-day average of wave length to Figure 7 and the related discussion to the Discussion section.

 

9. The resolution of the spatial maps & figures can be increased.

Corrected.

 

Comments on the Quality of English Language

Check the tenses of the sentences. There are present and present perfect tenses in a paragraph. See the paragraph in the Abstract.

There are some crucial errors.

Keywords should be ordered A to Z.

Use passive sentences. Check the sentences started by “we”. See the Abstract …

Many thanks for these points, we made the related corrections in the text.

Reviewer 3 Report

Thanks Osadchiev et al. for presenting this interesting work regarding submarine permafrost erosion. The paper is well written but have some space to improve. 

 

The manuscript don’t  have line number, making it not easy for reviewers to write comments. 

 

It’s not clear to me how the satellite data was used? Although it mentioned: “Areas of turbid zones reconstructed by this procedure was used to qualitatively study variability of erosion intensity at VS in response to external forcing.” Would be great if the author can provide more details.

 

Is it possible to user higher resolution satellite imagery such as Sentinel-2 (10 m) for certain periods after 2014? The resolution of MODIS is quite coarse (250 m? or 1000?). By using Sentine-2, the accuracy for calculating the area of turbid zone would be much higher. 

 

 

It would be helpful for reader to understand this work if the

 

Before 2000, there is not MODIS satellite imagery, how did you get information regarding Length of ice-free period? Number of turbid events, etc?

 

 

Page 4, it would be better to put the formular: DN/Dt  into a new line. 

 

Section 2.3. it’s not easy to follow this section. Hope the author can improve this section by providing more details instead of just citing a few papers. 

 

In the result section, some paragraphs such as the 3^rd and 4^th ones should be moved to method section. 

Author Response

Thanks Osadchiev et al. for presenting this interesting work regarding submarine permafrost erosion. The paper is well written but have some space to improve. 

 

The manuscript don’t  have line number, making it not easy for reviewers to write comments. 

We added line numbers to the manuscript.

 

It’s not clear to me how the satellite data was used? Although it mentioned: “Areas of turbid zones reconstructed by this procedure was used to qualitatively study variability of erosion intensity at VS in response to external forcing.” Would be great if the author can provide more details.

First, we reconstructed the exact value of area (in km²) of turbid zone visible at cloud-free and ice-free satellite images of VS. The area could be equal to zero, in this case the turbid zone was absent in the study region. Then we revealed the dependence of the reconstructed values at different days in 2000-2021 on synchronous wind-wave forcing conditions obtained from the numerical model. This information was added to Section 2.3.

 

Is it possible to user higher resolution satellite imagery such as Sentinel-2 (10 m) for certain periods after 2014? The resolution of MODIS is quite coarse (250 m? or 1000?). By using Sentinel-2, the accuracy for calculating the area of turbid zone would be much higher. 

Many thanks for this point. We use MODIS satellite imagery with spatial resolution of 250 m due to their daily coverage of the study region. Optical satellite products with higher resolution (e.g., Sentinel-2/3, Landsat 7/8, MERIS) could provide better accuracy for calculating the area of turbid zones, but have less frequent temporal coverage, which is crucial for this work. This point was clarified in the text.

 

Before 2000, there is not MODIS satellite imagery, how did you get information regarding Length of ice-free period? Number of turbid events, etc?

Information about ice-free periods in different parts of the Laptev Sea was obtained from satellite observations of sea ice performed since 1979 (e.g., Cavalieri and Parkinson, 2012). Note that information about sea ice conditions in the Arctic Ocean in 1979-2021 were used as input data for WAVEWATCH III numerical modeling. Periods and number of turbid events were reconstructed according to the equation, which represents dependence of area of the turbid zone at VS on 9-day average of wave length. Note that in case of 9-day average of wave length preceding a certain day was < 21 m, area of turbid zone at VS at this day was presumed to be zero, i.e., the turbid zone was absent. The related clarification was added to the text.

 

Page 4, it would be better to put the formular: DN/Dt  into a new line. 

Corrected. 

 

Section 2.3. it’s not easy to follow this section. Hope the author can improve this section by providing more details instead of just citing a few papers. 

According to your recommendation, we substantially reworked and improved Section 2.3.

 

In the result section, some paragraphs such as the 3^rd and 4^th ones should be moved to method section. 

We moved these paragraphs to the methods section according to your recommendation.

Round 2

Reviewer 2 Report

The track-changes document is missing in the system. The changed parts could at least be colourised. Therefore, we couldn’t follow the changes between the first and final forms of the article.

 

There are two main points that needs to be corrected in the article. According to comment 5 in the first round, additional suggested related works about sediment should be added in the paper.

 

The detailed explanation of the novelty of the paper is still missing. Also, there is no response to this comment (Comment 4).

 

As a final, a flowchart of the applied methodology is suggested as comment 1 in the first round. There is no information about the flowchart in the paper.

 

 

Thank the authors for their efforts on the paper revision and responses/corrections to the reviewers’ comments.

A final check has to be made by the authors. There are still minor typos.

Author Response

The track-changes document is missing in the system. The changed parts could at least be colourised. Therefore, we couldn’t follow the changes between the first and final forms of the article.

Please find the attached MS Word files with track-changed manuscript after both the first and the second revision rounds as the attachment to “author's notes to reviewer”. Note that the track-changed manuscript after the first revision round was already uploaded to the Susy submission system as the “non-published material”, not the “supplementary file”.

 

There are two main points that needs to be corrected in the article. According to comment 5 in the first round, additional suggested related works about sediment should be added in the paper.

The reviewer’s recommendation for references that should be referred in the manuscript included two references, namely, doi.org/10.1038/s43017-021-00232-1 and doi.org/10.54740/ros.2022.016. The first reference, (Irrgang et al., 2022, Nature Reviews Earth & Environment) is focused on abrasion of Arctic coasts and indeed is important for our study and we added it to the text (as reference [14]). The second reference, (Burgan, 2022, Rocznik Ochrona Środowiska) describes sediment discharges in Turkish rivers and has no relation to our manuscript. Note that we added multiple (>15) new references about coastline and seabed abrasion and marine sedimentation at the first revision stage. We believe that the number and coverage of references in the current state (62 references, the majority of them are about coastline and seabed abrasion and marine sedimentation in the Arctic Ocean) is enough.

 

The detailed explanation of the novelty of the paper is still missing. Also, there is no response to this comment (Comment 4).

The novelty of this paper consists in the fact that it is the first comprehensive study that addresses dynamics and variability of seafloor erosion in shallow areas in the Laptev Sea and provided the related assessments of sediment fluxes. The obtained results are of key importance for monitoring and evaluation of increasing subsea permafrost erosion in the Laptev Sea, which could be a potential and still uncounted contributor to regional CO₂ system. This issue was explicitly discussed in the Introduction and Conclusions.

 

As a final, a flowchart of the applied methodology is suggested as comment 1 in the first round. There is no information about the flowchart in the paper.

We describe the applied methodology in detail in the Introduction. Here is the related paragraph:

“This paper is focused on seafloor erosion at several largest shoals in the Laptev Sea, where this process is detected by satellite observations. The general scheme of the sug-gested methodology is the following. First, we calculate the area (in km2) of turbid zones (formed as a result of seafloor erosion at the shoals) visible at optical satellite imagery. As a result, we obtain the information about the intensity of seafloor erosion, albeit only during ~100 cloud-free and ice-free days during 2000-2021 due to satellite data temporal coverage. We compare the calculated areas of turbid zones with synchronous wind-wave conditions, reconstructed for the considered days using the numerical model. Once we obtain the dependence of intensity of seafloor erosion on wind-wave conditions, we could reconstruct this intensity at every ice-free day during 1979-2021 due to numerical model temporal coverage. Finally, we use this data and in situ measurements of sediment concentrations to assess the eroded sediment matter flux from this shoal during ice-free season in 1979-2021.”

We believe that there is no need to provide an additional figure with flowchart of the applied methodology, moreover, usage of methodological flowcharts is very uncommon for oceanographic scientific papers.

 

A final check has to be made by the authors. There are still minor typos.

Many thanks for this point, we performed the final check of the manuscript.

Author Response File: Author Response.docx

Reviewer 3 Report

Thanks for the revision. 

Author Response

Many thanks for your evaluation of our work.