Taking into consideration your extensive revisions and comprehensive responses, I have invited two of the reviewers to provide further reviews of the revised manuscript.

Dear authors,

In case you cannot see the most recent review by Referee 1, I paste this below. Please address these comments, and I will then be able to reach a final decision.

Best Regards,
Bob Marsh

Review: `The Whole Antarctic Ocean Model (WAOM v1.0): Development and
Evaluation, Revision 1’ by Richter et al.

In this revision the authors have substantially improved the manuscript, particularly via an overhaul of the evaluation of the simulated hydrography on the continental shelf. Unfortunately, this improved evaluation reveals serious biases in the continental shelf water masses. Most notably, there is an almost-complete absence of High Salinity Shelf Waters at sites such as the Ross and Weddell continental shelves, and a lack of Circumpolar Deep Water (CDW) circulating in the Amundsen and Bellingshausen Seas. Although the authors argue that the model is ready for process-oriented studies, my perspective is that the water mass biases make its applications rather limited: the model cannot be used to study dense shelf water formation, and is not well suited to studying CDW-driven melt of Antarctica’s most rapidly-melting ice shelves. These biases likely stem from the authors’ prescription of the ocean surface fluxes, rather than the more conventional approach simulating the evolution of the sea ice under a prescribed atmosphere.

That said, the authors are open about the model’s biases and readiness for addressing science questions, and they identify various experiments and analyses for which the model could be used in its present state. Thus, while I think the community would be better served by the authors publishing a further improved version of the model in which the major hydrographic biases had been somewhat ameliorated, I do not see this as a barrier to publication of the model in its current state.

Below I have included another round of comments and questions for the authors. Of these comments, the most significant pertain to the equilibration of the model at 4km and 2km resolutions. As many of these comments may require substantial changes to be made, particularly to the figures, my recommendation is that the manuscript be returned to the authors for further major revisions.


Comments/questions:

L29-32: This statement is correct, but don’t all models fall into one of these categories? I am struggling to understand what exactly the authors are aiming to convey with this sentence.

L48: The authors state that model parameters are “often” calibrated, but then cite only a single study in support of this statement. Does this really constitute “often”?

L50: Again “often”, this time with just two examples. If these were review articles then this would be reasonable, but these are just regular scientific studies.

L97-111: Have the authors tested the model with uniform stratification and no forcing to establish that their topographic smoothing and density Jacobian formulation of the pressure gradient force suppress spurious along-slope currents?

L130: I suggest an alternative naming to “heat flux into the ocean”. Based on the units and context, I infer that this quantity is some kind of restoring coefficient.

Fig. 2: The 10km run looks, to my eye, to have reached equilibrium, but it would be appropriate to include some statistical measure of this. The 4km run looks like it may still be drifting away from the 10km run - have the authors tried checking whether there is any statistically significant trend in the difference between the 10km and 4km melt rates at the end of the integration period?

Additionally, I would strongly encourage the authors to consider whether other measures of shelf water masses, e.g. mean bottom temperatures or salinities, indicate that the simulations have reached equilibrium.

L187: Why only the summer mean? The winter conditions are arguably more important for some processes, e.g. formation of dense shelf waters.

Fig. 3: As the amplitude of tidal fluctuations varies widely around Antarctica, this figure may be more insightful if the error were normalized by the root-mean-square tidal height fluctuations at each tide gauge.

Fig. 4: This figure shows that the 4km and 1km runs are much more similar than the 10km run. Is this simply because the 10km run has been integrated independently of the others for much longer (the 4km run is branched off the 10km run at year 5, then the 2km run is branched off the 4km run in year 7, and analysis is performed in year 8), or due to changes in the resolution of shelf processes?

It would also be helpful to include a second x-axis, along the top of the figure, showing the actual model grid spacings.

Fig. 8: These plots are difficult to compare because the data are presented as a straightforward scatter, causing many points to overlap one another and thus obscuring many details. I would recommend presenting these T/S diagrams as two-dimensional probability density functions instead. Information about the depths of water masses could be conveyed in separate panels via volumetric weighting of the depths contributing to each water mass bin.

Also, the “ISW” label doesn’t seem to be indicating any water masses in the left-hand panel.

Also, “AntarcticSurface” -> “Antarctic Surface” in the caption.

L304-305: Aren’t the waters below the surface freezing temperatures ice shelf waters?

L307: Formatting of citation.

L311: Format “degC”

L325: “temperature salinity transects”

L327: “hydrology” -> “hydrography”?

Fig. 9: The color bars for the middle panels are mis-labeled, I think.

Figs. 11-13: The biases in WAOM look to be quite severe: comparable to the variations in T and S in WOA. I suggest adding panels showing the T and S sections in WAOM to better visualize this.

Fig. 15: Same comment as for Fig. 8.

L367: “accurate” -> “accurately”

L384: citation formatting

L473-475: Has this issue been discussed earlier in the main text. I see it noted in Fig. D4, but not elsewhere.

Dear authors,

I am fully satisfied in your responses to the review of your revised manuscript, and in the further revisions you have made. Congratulations on a comprehensive paper outlining WAOM v1.0!

Best Regards,
Bob Marsh