Seasonal Variability of the Dynamics and Energy Transport in the Black Sea by Simulation Data

Round 1

Reviewer 1 Report

In the present paper authors have used a numerical method to analyze the seasonal variability of the velocity field and the mean and eddy kinetic energy. Authors have shown that a significant difference between the current dynamic in the southern and central parts of the Black Sea occurs, which mainly depends on the circulation regime. The topic is interesting to readers of Water and the article is well written and organized. The paper can be published after some corrections.

 

• Authors can mention the application or at least the main general conclusion of their work in the abstract.  
• Using six keywords is not very usual. Can authors drop one or merge two of them to use only one?
• Literature is well written. But authors can also mention the author's numerical method or similar ones that were employed to similar methods. One or two sentences could work.
• I understand that the authors don’t want to present the governing equations. That may make the paper much longer compared to what it is. Some readers may not be familiar with the topic. So adding a reference to governing equations can help them to find details.
• The results of Figure 4 is well written. In some cases, the reason for what is observed can be added to the text. For example, the authors say “ In 2011 (the basin-scale circulation regime), increased EKE values are observed from April till October, and the main EKE reserve is concentrated in the 0-60 m layer (Figure 4a). Throughout the year, the BT value is positive in the upper near-surface layer, i.e. EKE is increased due to the mean current kinetic energy”.They can detail the reasons and drivers for the observed changes in EKE.    
• Under Figure 8, the authors explain that “Differences in the spatial-temporal variability of BW for the two regimes appear at horizons below 40 m. Here, BW is positive only in summer 2011, while in 2016 the area of positive BW values is observed from February till the end of the year. An increase in the BW below 40 m is associated with positive density anomalies in the cold intermediate layer (CIL). Comparison of Figures 3 (BW diagrams) and 8 (temperature diagrams) shows that the location of the areas of maximum positive BW values coincides with the location of the CIL waters at depths of 40 -60 m. Thus, the contribution to the increase in the mean current kinetic energy due to the buoyancy work is provided not only by the 20-m surface layer but also by the 40-60 m layer.” They have well managed their discussion to conclude that the increase in mean current velocity is provided by the buoyant work in the 40-60 m layer. As we know, this cannot be perfectly true. Maybe authors can use phrases like can or may.
• Most of the discussions in the paper are well presented. The discussion of Figure 9 is very short. Authors just report the data. Perhaps they can link the results to the previous Figure to make their discussion nice.  
• Authors can mention the limitation of their model.
• I would like to ask authors to add their future plans to Section 5.

Author Response

Dear  Reviewer,

great thank you for your comments which helped us to improve the manuscript. We have added the changes in the revised manuscript.

Please see the attachment for details.

Author Response File: Author Response.docx

Reviewer 2 Report

This study is completely revolving aroung TKE, but this cannot be validated and the method is not scientific, because of the following:

• The authors simply reference the numerical method used for the simulation. But the method and its scientific soundness should be also described in the paper as well.
• How is the turbulence resolved or modelled? This should be described in detail. Have authors used RANS, LES, DNS or something else? How do they justify the resolving of eddies??
• Due to its nature of depending on turbulence, which can depend a lot on the input grid, the mesh uncertianty study must be done. Please do another simulation and present a GCI calculation. 
• Besides the reference on that the solver is validated (and future mesh validation study), what else can be done to validate the output? In conclusion, the authors should either give proper validation study or all input parameters available to reproduce results. This reviewer does not have access to suplementary materials.
• Can the authors please add a figure rendering the grid and coloring the depth map of the sea?

Author Response

Dear  Reviewer,

great thank you for your comments which helped us to improve the manuscript. We have added the changes in the revised manuscript.

Please see the attachment for details.

Author Response File: Author Response.docx

Reviewer 3 Report

The simulation model developed in this work will be applied to forecasting the current field in the present Black-Sea when the work is published in the “water” journal. A few comments are as follows;

 

• There are so many named-locations (ef. Bosphorus, ..). Please add a map indicating the location of the towns and straight indicated in the manuscript.
• Line 133 ; There in no Table S1.
• I think that the tide condition at the Bosphorus Straight is dominant to determine the current condition of Black Sea. No words referring to the tidal data at the straight, however, is derived in the paper. Why you mentioned only the balance of water and air mass?
• Figure 3; What point does the figure correspond to in Figure 2?
• Figure 3: What is the maximum water depth of the Black Sea? The seasonal change described in the Fig.3 is applicable even in the shallow water area?
• Figure 7; What is the SKIRON data?
• I think that Figure 7 is also estimated in the sophisticated simulation diagram. If you can access to the real observation data in any location, please include the comparison diagram of the observed and simulated sea level variation.
• What is the widest difference between the variation-characteristics of 2011 and 2016?

Author Response

Dear  Reviewer,

great thank you for your comments which helped us to improve the manuscript. We have added the changes in the revised manuscript.

Please see the attachment for details.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

This reviewer thanks the authors for the thorough explanations concerning the remarks. The manuscript is now enhanced in a way that it can be published.