Progress of the Oil Spill Risk Analysis (OSRA) Model and Its Applications
Round 1
Reviewer 1 Report
The ms provides the latest updates of the OSRA model concerning: a) the calculation of spills with volume of the order of 1million barrels named by the authors as catastrophic spills, b) the estimation of contact probability in the Gulf of Mexico and c) the introduction of simple equations to count the weathering processes. Finally the results of the application of the updated OSRA model to Ixtoc I oil spill, as well as at the Cook Inlet in Alaska are examined.
General comments
In addition to the large domain and long temporal extent of the OSRA capabilities, of ultimate importance is their resolution/frequency of the environmental forcing, an issue that the authors should take into account in their ms.
Large domains and long runs, comparable to OSRA domain in the Gulf of Mexico has been also implemented in other regions of similar sizes using other oil spill models, as for example the MEDSLIK II in the Mediterranean Sea (De Dominicis et al 2013) and in the North Atlantic (Sepp Neves et al. 2016 ), the MEDSLIK in the Red Sea (Hoteit et al. 2020 ) and in the Eastern Mediterranean Levantine Basin the last one estimating the probability distributions (Goldman et al 2015 ).
The provided definition for catastrophic spills should be clarified if its concern instantaneous releases (for example super tanker explosion) or spill leakages over a certain period of time or over the long examined periods.
The ocean input, i.e. currents and winds, indeed is critical for the generation of the trajectories from hypothetical or real spill locations. The accuracy of the impact (time, location, extend of impacted area, etc) at shoreline and at the coastal and offshore facilities depends also on the resolution of the ocean input. Moreover, the Stoke’s drift plays also a significant role for better estimation of the impact, especially at coastal areas. Therefore, the waves input is another important parameter that should be taken into consideration for the next upgrade of the OSRA model.
The inclusion of a simple algorithm representing the weathering processes in OSRA is important for estimating the volume of the spilled oil, especially at the impacted areas. However, the calculation of the transformation of the oil characteristics through the implementation of a more complete set of weathering algorithms/processes will provide more accurate information about the characteristics of the impacted oil at the shoreline and the coastal and offshore facilities.
It will be of interest to provide inter-comparison of the updated OSRA (with the simple weathering algorithm) for a short period of simulations, against any other well established oil spill model in the area having a more complex set of algorithms representing the weathering process.
The reference below are suggested to be included in the ms following the above relevant notes:
De Dominicis, M.; Pinardi, N.; Zodiatis, G.; Lardner, R. MEDSLIK-II, a Lagrangian marine surface oil spill model for short-term forecasting – Part 1: Theory. Geosci. Model Dev. 2013, 6, 1851-1869, doi:10.5194/gmd-6-1851-2013.
Hoteit, I., Abualnaja, Y., Afzal, S., Ait-El-Fquih, B., Akylas, T., Antony, C., Dawson, C., et al. (2020). Towards an End-to-End Analysis and Prediction System for Weather, Climate, and Marine Applications in the Red Sea. Bulletin of the American Meteorological Society, 1-61. https://doi.org/10.1175/bams-d-19-0005.
Goldman Ron, Eli Biton, Eran Brokovich, Salit Kark and Noam Levin (2015 ). Oil spill contamination probability in the southeastern Levantine basin, Marine Pollution Bulletin 91, 347-356. http://dx.doi.org/10.1016/j.marpolbul.2014.10.050
Sepp Neves Antonio Augusto, Nadia Pinardi, Flavio Martins (2016). IT-OSRA: applying ensemble simulations to estimate the oil spill risk associated to operational and accidental oil spills. Ocean Dynamics volume 66, 939–954, doi.org/10.1007/s10236-016-0960-0
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper is a good summary of the OSRA modeling over the past decade or so. It is well written and easy to read. I don’t have any major comments or concerns.
Minor comments:
Lines 56-58 Some text is missing.
In paragraph 2, the SIMAP model and risk assessments should be mentioned, as these are well established. For example:
French, D.P. and H. Schuttenberg, 1999. Evaluation of net environmental benefit using fates and effects modeling. Paper ID #321. In Proceedings of the 1999 International Oil Spill Conference, American Petroleum Institute, Washington, DC.
French-McCay, D.P, N. Whittier, D. Aurand, C. Dalton, J. J. Rowe, S. Sankaranarayanan, 2005. Modeling fates and impacts of hypothetical oil spills in Delaware, Florida, Texas, California, and Alaska waters, varying response options including use of dispersants. Proceedings, 2005 International Oil Spill Conference, Paper 399, Miami, Florida, American Petroleum Institute, Washington, DC. International Oil Spill Conference Proceedings: May 2005, Vol. 2005, No. 1, pp. 735-740. https://doi.org/10.7901/2169-3358-2005-1-735
French-McCay, D., D. Crowley, J. Rowe, M. Bock, H. Robinson, R. Wenning, A. H. Walker, J. Joeckel, and T. Parkerton. 2018. Comparative Risk Assessment of Spill Response Options for a Deepwater Oil Well Blowout: Part I. Oil Spill Modeling. Mar. Pollut. Bull. 133:1001–1015. https://doi.org/10.1016/j.marpolbul.2018.05.042.
Line 285-289: Most oils, even heavy ones, do not sink on their own after evaporative loss. Interactions with particulates are required to sink the oil. There are a few oils that are denser than fresh water, and very few denser than seawater. Revisions to clarify the sedimentation are suggested.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Journal: Journal of Marine Science and Engineering
Manuscript Number: 1051437
Review on manuscript “Progress of the Oil Spill Risk Analysis (OSRA) Model and Its Applications”by Ji et al.
General comments
The manuscript reports the recent innovations in the OSRA tool used for probabilistic environmental assessment of oil spill transport. Therefore, the manuscript fits into the scope of Journal of Marine Science and Engineering. Minor corrections are recommended. The main one is a context replacement of “weathering” in a sense of Eq. 2, 3 to “exponential decay.” It should be also emphasized that such an approach is oversimplifying, because the ~40-year history of the oil weathering research has shown that oil doesn’t behave so primitively.
More specifically:
L 57:Some part of the sentence is probably missed.
L 72: Could OSRA use the tide-induced transport,wave-induced transport (e.g., the Stokes drift, Langmuir circulation)? Could be OSRA downscaled? Please discuss these issues in the text.
L 188:Information about “the contacts of trajectories to every” land model segment is also very relevant. Could OSRA calculate these probabilities? Please discuss that in the text.
L 254:Could OSRA represent spreading? Please discuss that in the text.
L 254:Please add natural to “dispersion”.
L 272:In contrast to evaporation, the natural dispersion highly depends on the breaking wave regime. So, the statement “Oil from the water surface is typically removed within 5 days” seems not to be scientifically sound.
L 289:Interaction of oil with the coastline is very important. What kind of boundary conditions does OSRA use on the coastline, reflective/absorbing or the combination?
L 292:Please rephrase “computationally prohibitive”. Currently, that is a matter of development only.
L 313:Please add spatial and temporal resolutions of the model current, wind, ice fields used by OSRA.
L 327:Please describe an individual spill scenario (oil type, volume, rate of release, duration) including relevant parameters (i.e., windage coefficient, horizontal diffusion coefficient, number of Lagrangian particles, interpolation type, time step, integration scheme).
L 338:All the geographic names mentioned should be shown on map.
L 410:Please describe an individual spill scenario.
L 413:Without dispersants, the evaporation is the main reason for the oil loss, not biodegradation.
L 432:On which day?
L 455:I suggest removing Fig. 9. It shows that one-spill-a-day is not enough to represent statistically the months you’ve presented. Maybe the monthly climatology will look better.
Fig. 10:If possible sketch approximately the real center mass trajectory as in Fig.7 to show that a half-life time of 15 days is a better representation than without decay.
Some figures are found to be copied from the copyrighted publications. Please check the permission status.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
