On Barotropic Response of Arctic Seas to Polar Lows: A Case Study in the Barents Sea
Philip Callahan
Round 1
Reviewer 1 Report
General Comments:
No mention is made of the inverse barometer effect that is usually considered when calculating SSH anomalies. It will increase SSH in low pressure areas. If the effects shown are after considering this effect – the authors must check and state what corrections are applied in the SSHA values used – then the wind effects found are actually more substantial, and one has to wonder about the agreement between model and data shown in Figs 7, 8.
Specific Comments:
L 206: Sec 4.1 heading – missing word(s)
L 209, 234: Since the depth in the study area is <~500m, it would seem that the result in the end is not surprising and should be noted as such.
L 237: Missing “is” ahead of “not”
L 239: Unless Eq 7 is an absolutely well-known result, a reference is needed.
L 252: It is not immediately obvious why the result is the integral over all time as ws/bt includes all wavelengths (correct?).
Additionally:
I do not normally write "literary" (I cannot think of a good term to describe them) reviews where I in some way summarize the paper or provide a lot of background. I did/do not think that is the purpose of these reviews. If my writing a summary of the question addressed by the paper is to prove that I read it or was able to figure out the main point, I agree that this might be useful in some cases. In fact, for some papers that I cannot do this, I note in the original comments and am often fairly harsh about it.
I looked at the reference list and the titles seemed relevant, but I did not delve into them, but it seemed like this was a good little case study. the paper does not contain a discussion of the corrections that are or not applied to the data that they chose to use, and, in particular, the inverse barometer effect and the dynamic atmospheric correction (time/space-integrated atmospheric pressure effect) that would compete with the wind stress that they examine. I was surprised when I read the abstract and introduction and saw that they found a depression of sea level along the storm track. The discussion of wind stress seemed correct, but it is very incomplete without discussion of this other effect that is normally included with the data products but not applied to the sea surface height values (SSH) but may be included in SSH anomalies. It needs discussion and clarity to make a publishable paper.
Other than the font in the figures being too small and some of the lines too faint or close in color (a complaint I have about many of the papers), I thought they were quite appropriate.
There are occasional missing words or slightly awkward constructions, but the English is better than most.
Author Response
Please see the attachmentAuthor Response File: 
Author Response.pdf
Reviewer 2 Report
The paper describes the SSH anomalies recorded by satellite altimeters along the trajectories of two polar lows occurred in January 2017 and November 2018 in the Barents Sea.
Model simulations in the baroclinic and barotropic approximations of the ocean response were used to explain the observed SSH anomalies. Simulation results showed that baroclinic SSH anomalies are negligible and barotropic representation of ocean as driven by the surface wind stress vorticity is able to reasonably reproduce quantitatively the SSH anomalies along the tracks crossing the polar lows trajectories. The hourly ERA5 wind fields reanalyses were used to perform simulations.
The paper is well written, the descriptions of dataset and analysis procedure are comprehensive and all the details are reported. Likewise, the results are very well described and the ensuing discussion provides a clear picture of the mechanisms generating the observed SSH anomalies.
I wish the following explanation be reported in the final version of the manuscript:
p. 11 row 266-267: Please explain how the radius of maximum wind speed (claimed about 100 km) can be estimated from Figure 6a.
Author Response
Please see the attachmentAuthor Response File: Author Response.pdf
Reviewer 3 Report
Review of the Remote Sensing manuscript with title “On barotropic response of arctic seas to polar lows: a case study in the Barents Sea”, by Kudryavtsev et al. (2023).
The paper is a technical note on the influence of polar lows on the sea surface height in the Barents Sea. The authors’ goal is to study the spatial pattern of sea level anomalies and their temporal evolution at the passage of a polar low in the region. They furthermore aim to assess the relative importance of the baroclinic and barotropic contributions to sea level anomalies, and the impact of the anomalies on the ocean circulation. They succeed in their objectives by using a combination of reanalysis, satellite data and output from a simplified model.
I find that the paper has a worthwhile goal and is clearly presented both in terms of structure and language. The language is fluent, apart from minor grammar mistakes (like plural forms, articles and commas).
A minor point is that the model is first introduced in the discussion, while it is already mentioned in Figures 7-8 (see more comments below). This leaves the reader wondering what the model does until the discussion.
I recommend to accept the paper after minor revisions. Please find my detailed comments reported below.
Minor comments:
L9: One sentence about the motivation for this study should be included also at the beginning of the abstract.
L49-50: maybe you can add “the simplified model described in [9]”, to let the reader clearly understand that you’re using a previously published method.
L83-84: I assume that the cyclones passed over ice-free areas? Where the ocean is ice-covered, in equation (1) the difference between ice velocity and ocean velocity should be used instead of the 10-meter wind speed, and the drag coefficient is also different.
Equation (2): should the vorticity not have the opposite sign? As in: dxTy - dyTx
In any case, the animations and figures show correctly positive vorticity where the cyclone is passing.
L94-96: Maybe you can complete this sentence either by providing an average Drho/rho ratio in this region or including a reference to other studies where this is mentioned.
L102-107: It would be useful for the reader, interested in either reproducing your results or use the same data, if you could specify the name of the dataset you used. For instance, only of CryoSat-2 there are about 3 or 4 different versions on the ESA server alone (each obtained through different processing).
L115: I think this should be “November 2018”.
Caption / content of Figures 7-8: you first mention the model at this point of the paper, without it being introduced in the methods. Even though I understand the sense of using the model to “discuss” the observations, it could be useful to include the equations of the model in the methods first, and then discuss the output in the discussion.
L206: The question in the section subtitle is a bit difficult to understand. In particular the word “matter” does not fit here. Maybe you could say “Does the baroclinic response influence observations?” or “Is the baroclinic response visible from observations?”
L211-220, Equation (4): It would be useful to indicate more clearly what is the/one reference for this part, as it is the central part of the analysis from which stems the “smallness” of the barotropic contribution. Is this taken from reference [9]?
Equation (5): should it be “dhsbc ” instead of “hsbc ”?
Equations (7) and (8): the same is valid as for Equation (4).
The language is fluent, apart from minor grammar mistakes (like plural forms, articles and commas).
Author Response
Please see the attachmentAuthor Response File: Author Response.pdf
