Review of “ A decade-long hydrographic moored time seriesnear the Drygalski Ice Tongue, Terra Nova Bay, Ross Sea” by Cornelissen et al

This ESSD paper is a description of a decade-long time series from 3 moorings maintained in the western Ross Sea around the Drygalsky Ice Tongue in Terra Nova Bay. The region features polynyas and dynamic sea ice-ocean-glacier processes, and is a relevant sea ice production and AABW formation region. The paper provides a nice overview of the relevant processes, water masses and circulation in Terra Nova Bay and around the ice tongue, and additionally provides an overview of complementary data records from the region, which is especially helpful for those interested in a comprehensive overview of available data. As required for a technical/data paper, the authors provide technical background on mooring design, moored sensors including accuracies and quality control methods, and finally suggest possible use cases for their dataset. Overall, I have very little to complain and find that this paper is a nice overview of an important long-term record, and recommend publication after some minor improvements and clarifications.

Some general and more detailed comments below:

Icebergs and upper ocean sensors: Two of the moorings are indeed quite close to the surface at 50m and 75m, respectively. This is higher up than most standard moorings deployed around the Antarctic. Are these deployment locations generally safe from drifting icebergs or calvings? You did mention an iceberg impact once, but perhaps provide 1-2 sentences on whether/why icebergs are not a big risk.

On a similar note, having moorings extending into the euphotic zone really calls for including biogeochemical sensors or at least a fluorometer, which would clearly foster a multi-disciplinary interest in the moorings. The potential interest is accordingly mentioned in the last paragraph, but are there any plans to include such sensors in future deployments?

Figures: The figures are mostly fine. Including all the time series in each of the many subpanels makes it sometimes difficult to recognize details, although one can see features like seasonality and interannual differences. For the primary purpose of providing an overview, I think this is fine.

Fig7: I assume the colors of isopycnals in the top panels correspond to the density-colorbar? I would go with a standard TS-diagram, using simple black contour lines. The colors in the colorbar are really difficult to see. Unless I didn’t understand the idea behind the current design, I think it will be much easier to recognize. I’d recommend black contours with 1 or 2 density labels included and then the increments mentioned in the caption for clarity.

Fig 9: This is a useful way of outlining the major current ellipses, but again uses 16 small panels. Another idea to display the dominant average currents is to include vectors of the mean currents in the overview map in Fig.1. The text already provides a nice general overview, but to make it really reader-friendly, one could include the mean currents at the mooring locations and a few circulation arrows in Fig.1.

Stratification: Since stratification is mentioned prominently, perhaps the authors can consider to show an average CTD profile from the deployment CTDs in the beginning of the paper. Along with a broad overview of currents in the map, this would nicely introduce the water column structure in this region, which could further be used to motivate the choice of the sensor depths in the moorings.

L37: relatively

L170: “temperatures in the top 400m show a clear…” not clear where to see this. The sensor depths cover the top 275m and then again at 668m. Why 400m?

L175: again, I’d refer to 275m instead of 200-400m

Results section general remark: it would be helpful to point to specific figure and subpanels in the text, wherever certain features are mentioned in the mooring records. Reading these sections is sometimes a little tedious when trying to connect text and figures and distracts from reading.

L223 HSSW, formed

L244 and following lines: did you mean to refer to fig 9? Currently, fig 9 is not mentioned in the text

L262: “…changes may affect the stability of the ice tongue…” – so what is the expectation for the stability? Are there any signs or projections for enhanced warm water or other conditions that may lead to the erosion of the ice tongue?

L274 extent