Visual Appearance of Oil on the Sea
Round 1
Reviewer 1 Report
Dear Author,
I read your work with great interest and I propose publication after minor revision based on the comments below:
- Please, refer the source of the photographs you present in the paper. Are these photographs from your own database or taken from other sources (in this case you need permission).
- Section 7 of your paper is entitled "Discussion and Conclusions". Please, change the title into "Conclusions", because there is no "Discussion" in this section
Kind regards
Author Response
Response to Reviewer One
I kindly appreciate your careful review and constructive suggestions on my manuscript.
I read your work with great interest and I propose publication after minor revision based on the comments below:
Please, refer the source of the photographs you present in the paper. Are these photographs from your own database or taken from other sources (in this case you need permission).
The photographs are from my own collection or as noted in the figure legend. I did get permission and noted this in the legends for figures not my own.
Section 7 of your paper is entitled "Discussion and Conclusions". Please, change the title into "Conclusions", because there is no "Discussion" in this section
This has been changed.
Reviewer 2 Report
Review of “Visual Appearance of Oil on the Sea”
This manuscript attempted to provide a review of visual appearance of oil on the sea. Due to subjectiveness and uncertainty of visual assessment of oil on the sea, the work is not as important as it is claimed, rather it is meaningless or even misleading. This reviewer does not see any solid standards that are used in analyzing visual appearance of oil on the sea. The manuscript does not offer anything new, either. I am not convinced that the manuscript is worthy of publication in a peer-reviewed journal.
Author Response
Response to Reviewer Two
I kindly appreciate your careful review and constructive suggestions on my manuscript.
This manuscript attempted to provide a review of visual appearance of oil on the sea. Due to subjectiveness and uncertainty of visual assessment of oil on the sea, the work is not as important as it is claimed, rather it is meaningless or even misleading. This reviewer does not see any solid standards that are used in analyzing visual appearance of oil on the sea. The manuscript does not offer anything new, either. I am not convinced that the manuscript is worthy of publication in a peer-reviewed journal.
The paper has many novel and new findings. Overall, this is the first published paper to combine all the findings on the visual appearance of oil. Secondly, most of these findings, as will be detailed below, are new and novel. Specifically, the following are new findings:
• fundamental color relationships for thin slicks as shown in Figure 1
• Appearance of very thin slicks (sheens) as being the combination of reflectance from the surface, and the water surface
• The presentation of absorption and its effect on the appearance of oil
• Calculation of the average absorption of Petrobaltic and Romaskino oils
• The effect of the absorption of oils on the appearance of slicks past 3 µ,
• Re-calculation of the interference wavelengths and their appearances
• Effect of absorption combined with the interference wavelengths
• Comparison of color codes
• Comparison of needed thickness information with that attainable by color indications
• Critical review of color codes
• Applicability of measurements to color code comparison
• Actual comparison of passive microwave data to color code calculation of the MC-20 slick
• Comparison of the ASTM code with the Bonn code.
• The finding that color codes are not applicable to thicker slicks
• Review of discharge appearance and conclusion that discharges do not yield a unique appearance
• Origin of the red coloration in water-in-oil emulsions and the effect on their appearance
• Origin of the coffee-color from in oil-in-water emulsions and the effect on their appearance
• The combination of all these findings to yield a new scale of color codes eliminating some of the incorrect ones which have slipped into practice documents
It is noted by the reviewer that the 1972 reference (Hornstein) had interference data, however this paper was never published in the broad literature and very few people knew of its existence. Further, this data had to be verified and re-calculated before use in this paper. The 1972 paper had none of the above information. Further, if the author had used only the 1972 paper there would be only a few sentences of unverified information and not the remainder of the paper.
The presence of color codes that do not comply with the findings presented in the paper should indicate the strong need for this information.
Author Response File: 
Author Response.pdf
Reviewer 3 Report
This paper provides a practical review on the visual appearance of spilled and discharged oil on the sea, which will be helpful guides to oil spill researchers and responders. The author has many experiences on this field and points out what is needed for visual inspection of spilled oil on the sea. There are some minor corrections need to be revised before publish.
- Line 95: “very thin (< 3 µm)”, maybe 1 µm?
- Table 2: arrangement of numbers needs to be consistent (high to low number)
- Table 3: adsorption -> absorption
- Figure 3: boundaries of thicknesses need to be marked
Author Response
Response to Reviewer Three
I kindly appreciate your careful review and constructive suggestions on my manuscript.
This paper provides a practical review on the visual appearance of spilled and discharged oil on the sea, which will be helpful guides to oil spill researchers and responders. The author has many experiences on this field and points out what is needed for visual inspection of spilled oil on the sea. There are some minor corrections need to be revised before publish.
Line 95: “very thin (< 3 µm)”, maybe 1 µm?
Change made
Table 2: arrangement of numbers needs to be consistent (high to low number)
Table changed
Table 3: adsorption -> absorption
Table changed
Figure 3: boundaries of thicknesses need to be marked
The boundaries are the lines – I reformatted to make this clearer
Reviewer 4 Report
This is an already well-researched topic and for which this manuscript adds little.
In fact, this manuscript attempts to revisit a classic work, dated 1972, and largely addresses a retrospective of publications by the author himself on the same topic. It is an addition to another recent Review article, dated 2018.
Although this manuscript lacks relevant original content, the topic remains current and the text is easy and pleasant to read. However, even in the case of a Review, it would be desirable to address a complementary way currently used to predict the evolution and behavior of oil spilled at sea. To do so, having timely knowledge of the slick thickness would be important data to help guide ships in combating pollution.
No doubt that tele-detection is a widely-used technique employed with considerable success to define (approximately) the affected zones, to determine the extent of the spill, and to help the ships combat pollution. For that purpose, aerial detection sensors have been developed. However, under adverse meteorological conditions, they only provide sufficient information when used in combination.
One way to overcome such adverse weather conditions is to use numerical simulation. In preventive terms, numerical models could even represent the only method of planning the implementation of means of combating pollution at sea.
I accept that 'spreading equations are not good predictors of thick slicks' whether they are computed directly or indirectly through volume and area.
Having timely knowledge of the slick thickness would be an important entry data to verify/rectify the results obtained from predictive models of the evolution of the spill in real-time. This would make it possible to more accurately determine the extent of the spill and help guide ships in combating pollution.
Therefore, in this overall context, I would suggest a more comprehensive state-of-art. Some references (among others) that show the importance of numerical simulation in identifying the trajectory and fate of spilled oil at sea are:
- Wang et al., 2008. "Three-dimensional numerical simulation for transport of oil spills in seas" Ocean Engineering 35, 503–510, doi: 10.1016/j.oceaneng.2007.12.001.
- Do Carmo et al., 2010. "Oil Spills in Coastal Zones: Predicting Slick Transport and Weathering Processes" The Open Ocean Engineering Journal 3, 129-142, doi: 10.2174/1874835X01003010129.
- Deqi et al., 2010. "Numerical Simulation of the Trajectory and Fate of Spilled Oil at Sea" 4th International Conference on Bioinformatics and Biomedical Engineering, Chengdu, pp. 1-4, doi: 10.1109/ICBBE.2010.5516926.
Author Response
Response to Reviewer Four
I kindly appreciate your careful review and constructive suggestions on my manuscript.
This is an already well-researched topic and for which this manuscript adds little.
In fact, this manuscript attempts to revisit a classic work, dated 1972, and largely addresses a retrospective of publications by the author himself on the same topic. It is an addition to another recent Review article, dated 2018.
Although this manuscript lacks relevant original content, the topic remains current and the text is easy and pleasant to read. However, even in the case of a Review, it would be desirable to address a complementary way currently used to predict the evolution and behavior of oil spilled at sea. To do so, having timely knowledge of the slick thickness would be important data to help guide ships in combating pollution.
No doubt that tele-detection is a widely-used technique employed with considerable success to define (approximately) the affected zones, to determine the extent of the spill, and to help the ships combat pollution. For that purpose, aerial detection sensors have been developed. However, under adverse meteorological conditions, they only provide sufficient information when used in combination.
The paper has many novel and new findings. Overall, this is the first published paper to combine all the findings on the visual appearance of oil. Secondly, most of these findings, as will be detailed below, are new and novel. Specifically, the following are new findings:
• fundamental color relationships for thin slicks as shown in Figure 1
• Appearance of very thin slicks (sheens) as being the combination of reflectance from the surface, and the water surface
• The presentation of absorption and its effect on the appearance of oil
• Calculation of the average absorption of Petrobaltic and Romaskino oils
• The effect of the absorption of oils on the appearance of slicks past 3 µ,
• Re-calculation of the interference wavelengths and their appearances
• Effect of absorption combined with the interference wavelengths
• Comparison of color codes
• Comparison of needed thickness information with that attainable by color indications
• Critical review of color codes
• Applicability of measurements to color code comparison
• Actual comparison of passive microwave data to color code calculation of the MC-20 slick
• Comparison of the ASTM code with the Bonn code.
• The finding that color codes are not applicable to thicker slicks
• Review of discharge appearance and conclusion that discharges do not yield a unique appearance
• Origin of the red coloration in water-in-oil emulsions and the effect on their appearance
• Origin of the coffee-color from in oil-in-water emulsions and the effect on their appearance
• The combination of all these findings to yield a new scale of color codes eliminating some of the incorrect ones which have slipped into practice documents
It is noted by the reviewer that the 1972 reference (Hornstein) had interference data, however this paper was never published in the broad literature and very few people knew of its existence. Further, this data had to be verified and re-calculated before use in this paper. The 1972 paper had none of the above information. Further, if the author had used only the 1972 paper there would be only a few sentences of unverified information and not the remainder of the paper.
The presence of color codes that do not comply with the findings presented in the paper should indicate the strong need for this information.
One way to overcome such adverse weather conditions is to use numerical simulation. In preventive terms, numerical models could even represent the only method of planning the implementation of means of combating pollution at sea.
I accept that 'spreading equations are not good predictors of thick slicks' whether they are computed directly or indirectly through volume and area.
Having timely knowledge of the slick thickness would be an important entry data to verify/rectify the results obtained from predictive models of the evolution of the spill in real-time. This would make it possible to more accurately determine the extent of the spill and help guide ships in combating pollution.
Therefore, in this overall context, I would suggest a more comprehensive state-of-art. Some references (among others) that show the importance of numerical simulation in identifying the trajectory and fate of spilled oil at sea are:
- Wang et al., 2008. "Three-dimensional numerical simulation for transport of oil spills in seas" Ocean Engineering 35, 503–510, doi: 10.1016/j.oceaneng.2007.12.001.
- Do Carmo et al., 2010. "Oil Spills in Coastal Zones: Predicting Slick Transport and Weathering Processes" The Open Ocean Engineering Journal 3, 129-142, doi: 10.2174/1874835X01003010129.
- Deqi et al., 2010. "Numerical Simulation of the Trajectory and Fate of Spilled Oil at Sea" 4th International Conference on Bioinformatics and Biomedical Engineering, Chengdu, pp. 1-4, doi: 10.1109/ICBBE.2010.5516926.
While numerical simulation may be interesting, it does not solve the problem of the basic knowledge of processes and data bases necessary to proceed with modeling. The logic follows below
Physical Chemical Studies →
Knowledge of Process/Behavior Database→
Modelling to unknown situations
While it would be good to have slick thickness on a real time basis, this can be accomplished with real-time measurements. See Fingas, M. “The Challenges of Remotely Measuring Oil Slick Thickness,” Remote Sensing, 28 pp. 2018, 10,(2) 319; doi:10.3390/rs10020319
Real time thickness measurements are possible - not a topic of the current paper, however.
Round 2
Reviewer 2 Report
No essential changes have been made from the original version manuscript. So, my comments and concerns still stand. This manuscript serves as a review of previous papers, mostly from the author himself's. Nothing really new or substantial that is worthy of publication as a peer-reviewed paper. Also, by visual appearance, the method is very subjective, and what is stated may be misleading. I don't think the manuscript should be accepted.
