Annual evolution of the ice–ocean interaction beneath landfast ice in Prydz Bay, East Antarctica

Hu, Haihan; Zhao, Jiechen; Heil, Petra; Qin, Zhiliang; Ma, Jingkai; Hui, Fengming; Cheng, Xiao

doi:https://doi.org/10.5194/tc-17-2231-2023

Articles | Volume 17, issue 6

https://doi.org/10.5194/tc-17-2231-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/tc-17-2231-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 17, issue 6

Research article

|

02 Jun 2023

Research article |

| 02 Jun 2023

Annual evolution of the ice–ocean interaction beneath landfast ice in Prydz Bay, East Antarctica

Haihan Hu, Jiechen Zhao, Petra Heil, Zhiliang Qin, Jingkai Ma, Fengming Hui, and Xiao Cheng

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Final revised paper (published on 02 Jun 2023)
Preprint (discussion started on 30 Aug 2022)

Interactive discussion

Status: closed

RC1:
'Comment on tc-2022-125', Anonymous Referee #1, 16 Sep 2022

The comment was uploaded in the form of a supplement: https://tc.copernicus.org/preprints/tc-2022-125/tc-2022-125-RC1-supplement.pdf

Citation: https://doi.org/10.5194/tc-2022-125-RC1
- AC1: 'Reply on RC1', Haihan Hu, 18 Nov 2022
  
  Thank you very much for your detailed comments on the manuscript. We have made careful modifications according to your suggestions, and all comments are replied to one by one in RED. The response is detailed in the supplement.
  
  Citation: https://doi.org/10.5194/tc-2022-125-AC1
RC2:
'Comment on tc-2022-125', Anonymous Referee #2, 14 Oct 2022
Landfast ice is one of the important components of Antarctic sea ice. Its growth and decay processes are closely coupled with local climate and affects local ecosystems. Due to the effect of tides, the ocean heat flux under the landfast ice is very important for the growth and decay of sea ice, and has the multi-scale characteristics of temporal changes. Therefore, it is of great significance to simultaneously carry out the observations of the landfast ice mass balance and the underneath ocean process. However, there are still no (to my knowledge) relevant observation and research been carried out in the Prydz Bay, East Antarctica.

In this study, an observation system of landfast ice and underneath ocean processes close to the shore off Zhongshan Station, Prydz Bay, East Antarctica, has been preliminarily established. Based on the observed data, the ocean heat flux under the ice has been parameterized, and the adjustment of tidal processes on the ocean heat flux has been analyzed, as well as the impact of the latter on the rate of sea ice growth and decay. It is a research achievement worth publishing. However, there are still some problems in the analysis and expression of the paper at present. Thus I recommend that the paper could be considered for publication after major revision.

General comments:

The author only gives the observation data of less than 10 days, so the representativeness of the data and whether the corresponding analysis result is robust are most worthy of discussion. If possible, the author is strongly recommended to provide longer observation data series to support the research conclusion

The growth and decay process of landfast sea ice is very sensitive to water depth. In this study, three observation equipment were not installed together. Although they were not far apart, the water depth was quite different. Therefore, how to judge the impact needs further discussion. Or it is necessary to further analyze the difference of sea ice thickness time seriesat the three measuring sites.

Limitations, errors and uncertainties of measurement and parameterization methods also need to be discussed, which are missed now.

Special comments:

Line 28, “As a structural part of the polar ecosystem”, what is the meaning of structural part here.

Line 36 “Fast ice”use the consistent terminology pls.

Line 99 “at an accuracy of ±0.0625â”, This is the resolution, not the accuracy. Its accuracy is 0.1â.

Line 102 “The records showed that snow and ice thickness was 0.045 m and 0.440 m on 16 April, while 0.020 m and 0.460 m”The measurement accuracy of snow and sea ice thickness is 0.01m, so three decimal places are unnecessary.

Line 115 “with a maximum of 4.24â between”similar as Line 102. One decimal place is enough. Similar problems can be identified somewhere else.

Line 124, “However, after the 21 April, there was a decrease in the thickness of the landfast ice, with basal melt accounting for nearly 2 cm.” The accuracy of SIMBA data in identifying sea ice bottom is 2cm, so the uncertainty of melting of 2cm here is relatively large.

Line 144 “The diurnal anomalies based on the according daily mean.”change to “The deviation relative to the according daily mean.”

The paper has given a lot of equations, and these formulas are very basic for both ocean and sea ice physics. Therefore, I suggest that only references should be given, and it is unnecessary to list them all.

The estimation uncertaintyof ocean heat flux by the residual energy method is very dependent on the calculation time interval, and there would be large errors for high-frequency calculations as shown in Figure 9.

Line 280 “the height of the mixing layer temperature above freezing point”change to “the deviation of the mixing layer temperature above freezing point”.

Line 292, here miss the start for u as the superscript.

11, can be combined with the Fig.10.

The influence of tides in the study area on sea ice growth rate has been observed and analyzed, which can be referred to:

Lei et al., A New Apparatus for Monitoring Sea Ice Thickness Based on the Magnetostrictive-Delay-Line Principle, Journal of Atmosphere and Oceanic Technology, 2009.
Citation: https://doi.org/10.5194/tc-2022-125-RC2
- AC2: 'Reply on RC2', Haihan Hu, 18 Nov 2022
  
  Thank you very much for your detailed comments on the manuscript. We have made careful modifications according to your suggestions, and all comments are replied to one by one in RED. The response is detailed in the supplement.
  
  Citation: https://doi.org/10.5194/tc-2022-125-AC2

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload

ED: Reconsider after major revisions (further review by editor and referees) (21 Nov 2022) by Christian Haas

AR by Haihan Hu on behalf of the Authors (04 Jan 2023) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (12 Jan 2023) by Christian Haas

RR by Ruibo Lei (18 Jan 2023)

Suggestions for revision or reasons for rejection

General comments:
1)During field deployment, how to ensure that the attitude change of ADV did not affect the current measurement, or how to eliminate the influence during data processing?
2)4.2 It is difficult to say that there is a direct connection between the changes in large-scale sea ice and marine environmental conditions and the local air-ice-sea interaction at the landfast ice close to the shore. Although some parameters have synchronous seasonal changes, it can only consider that the seasonal change patterns of these parameters are consistent, rather than the dynamic mechanism. In addition, it is difficult to support some of the author's assumptions in terms of the data and analysis given, thus I suggest deleting this section or only retaining some simple qualitative analysis.

Special comments:
3)Line 12: “The ice–ocean interaction is one of the main drivers of sea ice mass balance in the Polar Regions” --This is very vague for the study of sea ice thermodynamic process. You should emphasize the importance of high-frequency observation and high-precision estimation of ice-sea heat exchange for assessing the role of ocean heat flux in the mass balance of landfast ice.
4)The magnitude heat flux, seawater density: One decimal place is enough.
5)Line 25 “showed a typical period of 0.5 days” change to: showed a typical half-day period.
6)Introduction: You highlight the importance of landfast ice, and oceanic heat for ice mass balance, but miss the importance of high-frequency observation and high-precision estimation of ice-sea heat exchange. You also can give some successful cases (i.e., MOSAiC) on the estimation of oceanic heat flux under the ice based on similar observation strategy.
7)“global warming has been becoming more and more significant,”: In fact, it is not correct, such as the hiatus of temperature rising.
8)Line 76 “the second Chinese Antarctic scientific research station, which was established in February 1989 and operated year-round from then on” -- I don’t think the history of Station is a useful information for your study.
9)Line 105 “when he worked as the wintering team member in Zhongshan Station”: it is also useless information.
10)Line 166 “The 4.8 m long SIMBA temperature chains recorded the vertical temperature profiles of air–snow–ice–ocean every 6 hours.” moved to the section of method.
11)Line 186 “indicating the influence of short-term weather systems on ice evolution.”: The main impact should be the increase of heat content of ocean, not the increase of air temperature. The response of sea ice growth to changes in air temperature has some hysteresis.
12)Figure 2： change the sensor number to depth relative to sea level or ice surface please.
13)Line 206: “which attributed to the snow isolation effect on ice and ocean.”-- Cannot only attributed to the snow isolation effect.
14)Ocean density, salinity-- would be better “seawater density and salinity”.
15)Figure 5: How to explain the changes in current direction distribution and magnitude from April to May?
16)Line 308 “methods were consistent with the previous studies but based on a higher temporal resolution”: It is difficult to say that the difference is tens of watts is “consistent ”. It can only be said that the seasonality of oceanic heat flux given by different methods is consistent. The quantitative difference may be related to specific methods and environmental parameters of the given year. In addition, the estimation of oceanic heat flux at the ice bottom based on the residual energy method will produce great errors in a short time window.
17)“E et al., (2013).”: It is from Huang et al. (2013). Right?
18)“PSD peaks”: what is the PSD here?
19)Figure 9: “The results of spectral analysis”: the result is very strange for me? How to obtain such probability distribution?

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RR by Anonymous Referee #1 (24 Jan 2023)

ED: Reconsider after major revisions (further review by editor and referees) (04 Feb 2023) by Christian Haas

AR by Haihan Hu on behalf of the Authors (17 Mar 2023) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (21 Mar 2023) by Christian Haas

RR by Ruibo Lei (27 Mar 2023)

Suggestions for revision or reasons for rejection

The author has made corresponding revisions based on the last round of review comments, most of which are positive and worthy of recognition. For the latest version of the draft, the biggest innovation of this study is to use observational data from an ice season to reveal the role of tidal processes in the mass balance of landfast ice in the Antarctic Prydz Bay. The revised version has provided a detailed analysis of this issue, which also highlights the differences between this work and previous studies. Therefore, I recommend that it can be considered for publishing after some minor revisions.
Here are some special comments:
1)Line 31 “long-term observations” change to “Cross-seasonal observations”.
2)Line 34-40: I don't think the climate and sea ice changes in the Arctic have anything to do with your study, as I said last time.
3)Line 90 “the second Chinese Antarctic scientific research station, which was established in February 1989 and has been operated year-round since its establishment” -- just delete it.
4)The Operational Mercator global ocean reanalysis products: I do not believe that the reanalysis data of the ocean has the ability to solve the ocean processes under landfast ice with only <100 m from the shore, that having complex topographic features.
5)Line 199 and other texts: “The annual mean ”: Actually, you don't have a year of observational data.
6)Line 202 “which are similar to previous observations”, Further comparison with the following study is necessary because the landfast ice near Zhongshan Station will be affected by the terrain and distribution of grounding icebergs.
Lin L, Lei R, Hoppmann M, Perovich D K, and He H. 2022. Changes in the annual sea ice freeze–thaw cycle in the Arctic Ocean from 2001 to 2018, The Cryosphere, 16, 4779–4796, https://doi.org/10.5194/tc-16-4779-2022, 2022.
7)Line 210 “indicating the influence of the air–ice–ocean interactions on the ice evolution”: just delete it, it is a correct but meaningless discussion.
8)Figure 2: It is best to provide both snow and ice thickness in-situ observation data. In addition, I do not believe that during some winter periods, there were no snow at all, and there was still 2-6 cm of snow.
9)“after sublimation in summer”: How do you tell if it's sublimation rather than melting.
10)Figure 3: The density of seawater does not make much sense, and the deviation of seawater temperature above freezing point should be given.
11)Line 252-255 just remove it.
12)Line 265 “ the horizontal current exhibited a similar distribution in all three directions”: there are three directions for the horizontal current?
13)Figure 4 “Please note that the percentage scales are different in the different sub-panels. ”: use the same scale please.
14)Line 285 “but a practical value is more realistic in the Fc ”: it is in the Fl?
15)Table: remove it because it give the information repeated from the above figure.
16)Line 351 “ and fill up the data gap”-- change to “ fill up the knowledge gap”
17)Line 487 “such as ice thickness radar, ocean temperature chains, and ice salinity gauges”: Actually, I don't know what are the ice thickness radar and ice salinity gauges.

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RR by Anonymous Referee #1 (31 Mar 2023)

ED: Publish subject to minor revisions (review by editor) (15 Apr 2023) by Christian Haas

AR by Haihan Hu on behalf of the Authors (19 Apr 2023) Author's response Author's tracked changes Manuscript

ED: Publish subject to technical corrections (02 May 2023) by Christian Haas

AR by Haihan Hu on behalf of the Authors (06 May 2023) Author's response Manuscript

Short summary

The oceanic characteristics beneath sea ice significantly affect ice growth and melting. The high-frequency and long-term observations of oceanic variables allow us to deeply investigate their diurnal and seasonal variation and evaluate their influences on sea ice evolution. The large-scale sea ice distribution and ocean circulation contributed to the seasonal variation of ocean variables, revealing the important relationship between large-scale and local phenomena.