the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 16 Feb 2024
Brief communication: A low-cost surface vehicle for studying the near-terminus region at tidewater glaciers
Abstract. The oceanic region at the terminus of tidewater glaciers is under-explored, yet the processes occurring there are critical to our understanding and assessment of climate-change-induced ice loss. This region is hazardous for humans to directly access, necessitating exploration using unmanned robots. This paper discusses the design, development and deployment of a low-cost remote-controlled surface vehicle for in-situ studies in the near-terminus region. The robot is instrumented with passive acoustic, conductivity-temperature-depth and video recorders, and is able to successfully profile short transects in the proximity of, or even at, the terminus region.
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RC1: 'Comment on egusphere-2024-32', Anonymous Referee #1, 14 Apr 2024
In this Brief communication, Vishnu and colleagues describe the design, development , and deployment of a low-cost remote-controlled surface vehicle equipped with passive acoustic, CTD probe, and video recorders. In addition to the technical description of the robot, they present some examples of the data acquired during the test campaign in Svalbard. Overall, despite its small size and limited payload capacity, the vehicle provides a useful platform for conducting field measurements in the direct vicinity of the calving front, enabling safe operation in the critical zone. The low overall cost of the system makes it expendable, rendering it suitable for conducting risky operations where there is a high probability of equipment loss due to adverse sea and ice conditions. As the authors correctly point out, there is a flagrant lack of in situ data collected very near the ice-ocean interface, and the resulting data gap poses a challenge to model calibration and validation. In this context, there is a pressing need for development of an instrument capable of collecting multi-sensor data in the direct vicinity of the ice terminus. The instrument setup is thoroughly described, with clear examples of field deployment and obtained data. In this regard, despite some minor issues, this note is generally well-written and complemented with informative photos and plots.
However, I am afraid that the instrumentation and methods presented at the moment do not appear to be sufficiently novel to warrant publication in TC. For a decade now, there have been several studies utilizing autonomous vehicles for surveys near the calving front, the only difference is that this setup seems to be much cheaper. I find the rationale for publishing this work as a brief communication in The Cryosphere somewhat unclear. In my opinion, a comprehensive presentation of measurements conducted with the robot, complemented with a profound analysis and interpretation of the results, would certainly be of interest to the journal's readers. It may have been more appropriate to submit it to a journal with a specific focus on scientific instrumentation. Currently, the content of this manuscript would likely be better suited as a supplementary methods section within a larger, comprehensive research article detailing results rather than solely focusing on the instrumentation.
Additionally, after reviewing the manuscript I'm left with the impression that this article may be considered an example of salami publishing strategy: releasing smaller works to bolster the publication record of the authors. This impression is reinforced by the auto-citations within the text, some of which seem unnecessary or point to unpublished work of the first author, where other publications might have been more suitable. It's worth reminding that such strategy is discouraged by the publisher, obliging authors to avoid fragmentation of research papers (https://www.the-cryosphere.net/policies/obligations_for_authors.html). I would also like to remind the authors that the Brief communication should be only 2-4 journal page long and have maximum 20 references. This submission seems to exceed those limits.
Despite these concerns, the setup described in the manuscript holds promise and could be of interest to scientists studying ice-ocean processes at smaller tidewater glaciers. Still, I am skeptical about the applicability of this robot to measurements at larger glaciers (e.g., Greenlandic fjords). Both the effective range of the vehicle and the working range or depth of the instruments appear to be too limited for this. As a side note, the name "GLAMOR" could be misleading, as "ablation" typically refers to total or surface ablation (Cogley et al., 2011), whereas this robot measures variables only related to frontal ablation.
Finally, the manuscript lacks a Data Availability section. No data or code has been provided for reviewers or potential participants in the Open Discussion phase, and once more, I do not see a clear reason for such omission.
Specific comments:page 1 line 1: What is "The oceanic region at the terminus of the tidewater glacier"?
page 1 line 8: Why "ice-sheet melting" in particular in this context?
page 1 lines 8-9: Why do you refer to "polar ice sheets"?
page 1 line 11: Ice loss takes place at the glacier terminus, not near the glacier front
page 1 line 14: up to
page 1 line 16-17: of frontal ablation
page 1 line 17: What "topological morphology"? Could you please elaborate on that?
page 1 line 19: Is Vishnu et al., 2023 the best citation here? Were there no previous works on this subject, such as works by Erin Petit and her team, for example, or even older articles?
page 1 line 21: I find the auto-citation rate impressive, and frankly unacceptable. I have no access to Vishnu et al., 2024 (submitted to Science Advances). Please eliminate this reference.
page 2 line 26: Why do you mention the grounding line in this context?
page 2 line 35: As already stated above, the term "ablation" (unqualified) refers to total or surface ablation (Cogley et al., 2011). Therefore, the reader might expect a description of a robot that is designed to monitor surface ablation, which would require a completely different setup. I suggest rewording the robot name.
page 2 line 43-44: Please rewrite this sentence eliminating brackets
page 3 line 60: Around 83?
page 3 line 64: Is this application designed only for smartphones?
page 3 line 83: chance -> risk
page 5 Figure 2: Provide imagery acquisition dates, scale bar is missing
page 5 line 91: The correct place names are: Hansbreen (https://placenames.npolar.no/placename/53109416-bf7b-5e1d-86f1-768ef97a9dca) and Paierlbreen (https://stadnamn.npolar.no/Paierlbreen/Svalbard/5941fdba-64f4-5273-b0b6-9925db17a3f2)
page 5 lines 99-100: Please rephrase this sentence
page 6 line 128: Numbering is missing (2.) here and in the following lines
page 6 lines 133-134: Please rewrite this sentence eliminating brackets
page 6 line 136: infrared light source
page 7 Figure 3: panel a) is missing a label and the plot is unclear
page 7 lines 138-140: How would you estimate the size distribution from such imagery (upwards looking)?
page 8 line 146: "infrequently studied region" - please rephrase
page 9 line 178: "Improvisations"?
page 9 lines 195-200: How about the acoustically active depth at other sites?
page 9 line 201: What voltage?References:
Cogley, J.G., R. Hock, L.A. Rasmussen, A.A. Arendt, A. Bauder, R.J. Braithwaite, P. Jansson, G. Kaser, M. Möller, L. Nicholson and M. Zemp, 2011, Glossary of Glacier Mass Balance and Related Terms, IHP-VII Technical Documents in Hydrology No. 86, IACS Contribution No. 2, UNESCO-IHP, ParisCitation: https://doi.org/10.5194/egusphere-2024-32-RC1 -
RC2: 'Comment on egusphere-2024-32', Anonymous Referee #2, 16 Apr 2024
Brief communication “A low-cost surface vehicle for studying the near-terminus region at tidewater glaciers” by Hari Vishnu and others.
- General comments
This paper reports the application of a commercially available portable unmanned water surface vehicle for measurements in front of a tidewater glacier. The region near the calving front is a key to understanding ice-ocean interaction, but in-situ measurements are sparse because the region is difficult to approach. The use of an unmanned water vehicle is a solution to perform ocean measurements and such measurements have been reported in several glaciers. The authors use an inexpensive unmanned vehicle with some customisation of both hardware and software. The author’s interest is underwater acoustic measurement and CTD profiling, which were performed by mounting sensors on the vehicle and by towing a float equipped with instruments.
In general, the provided information is useful for readers planning a similar observation. The text is clearly and plainly written. My only concern is the novelty and significance of the device and procedure, which are required for publication as a journal article. Among the three categories of Brief Communications of The Cryosphere, the subject reported in the manuscript is relevant with “report new developments, significant advances, and novel aspects of experimental and theoretical methods and techniques which are relevant for scientific investigations within the journal scope” (https://www.the-cryosphere.net/about/manuscript_types.html). In-situ observation near the calving front is difficult, but already been reported in more than a few studies. Similar and more robust unmanned devices have been used in the previous studies. Something new about the device used in this study is its low cost. I agree that an inexpensive instrument helps research, but I am afraid that reporting a field test of a commercially available instrument does not meet the standard of the journal. It should be decided by the editorial team, but I expect more novelty in a paper published in The Cryosphere. I understand that the authors collected data from the operation of the device, which I assume will be published elsewhere. The material presented here may fit better as the methodology or supplementary information of such a publication.
- Specific comments:
Line 6: What do you mean by “even at”?
Line 26: Consider omitting “near the grounding line” because it is not relevant here.
Line 64: Is “Chasing cellphone app” the same application as mentioned in Line 53?
Figure 1: Please provide the length of the device as a scale of the images. Please also enlarge the instruments, particularly (d) and (e). In (d), it is not sure if the instruments are directly under the ice hang.
Figure 2: Provide a scale and date of acquisition of the background image.
Figure 3: Provide scales to the images.
Line 198: What do you mean by “maximum acoustically active depth”? How do you find that depth?
Figure B2: Please indicate in the figure where are the hydrophone and CTD.
Showing a more technical photograph and/or sketch of the vehicle is helpful.
Citation: https://doi.org/10.5194/egusphere-2024-32-RC2
Status: closed
-
RC1: 'Comment on egusphere-2024-32', Anonymous Referee #1, 14 Apr 2024
In this Brief communication, Vishnu and colleagues describe the design, development , and deployment of a low-cost remote-controlled surface vehicle equipped with passive acoustic, CTD probe, and video recorders. In addition to the technical description of the robot, they present some examples of the data acquired during the test campaign in Svalbard. Overall, despite its small size and limited payload capacity, the vehicle provides a useful platform for conducting field measurements in the direct vicinity of the calving front, enabling safe operation in the critical zone. The low overall cost of the system makes it expendable, rendering it suitable for conducting risky operations where there is a high probability of equipment loss due to adverse sea and ice conditions. As the authors correctly point out, there is a flagrant lack of in situ data collected very near the ice-ocean interface, and the resulting data gap poses a challenge to model calibration and validation. In this context, there is a pressing need for development of an instrument capable of collecting multi-sensor data in the direct vicinity of the ice terminus. The instrument setup is thoroughly described, with clear examples of field deployment and obtained data. In this regard, despite some minor issues, this note is generally well-written and complemented with informative photos and plots.
However, I am afraid that the instrumentation and methods presented at the moment do not appear to be sufficiently novel to warrant publication in TC. For a decade now, there have been several studies utilizing autonomous vehicles for surveys near the calving front, the only difference is that this setup seems to be much cheaper. I find the rationale for publishing this work as a brief communication in The Cryosphere somewhat unclear. In my opinion, a comprehensive presentation of measurements conducted with the robot, complemented with a profound analysis and interpretation of the results, would certainly be of interest to the journal's readers. It may have been more appropriate to submit it to a journal with a specific focus on scientific instrumentation. Currently, the content of this manuscript would likely be better suited as a supplementary methods section within a larger, comprehensive research article detailing results rather than solely focusing on the instrumentation.
Additionally, after reviewing the manuscript I'm left with the impression that this article may be considered an example of salami publishing strategy: releasing smaller works to bolster the publication record of the authors. This impression is reinforced by the auto-citations within the text, some of which seem unnecessary or point to unpublished work of the first author, where other publications might have been more suitable. It's worth reminding that such strategy is discouraged by the publisher, obliging authors to avoid fragmentation of research papers (https://www.the-cryosphere.net/policies/obligations_for_authors.html). I would also like to remind the authors that the Brief communication should be only 2-4 journal page long and have maximum 20 references. This submission seems to exceed those limits.
Despite these concerns, the setup described in the manuscript holds promise and could be of interest to scientists studying ice-ocean processes at smaller tidewater glaciers. Still, I am skeptical about the applicability of this robot to measurements at larger glaciers (e.g., Greenlandic fjords). Both the effective range of the vehicle and the working range or depth of the instruments appear to be too limited for this. As a side note, the name "GLAMOR" could be misleading, as "ablation" typically refers to total or surface ablation (Cogley et al., 2011), whereas this robot measures variables only related to frontal ablation.
Finally, the manuscript lacks a Data Availability section. No data or code has been provided for reviewers or potential participants in the Open Discussion phase, and once more, I do not see a clear reason for such omission.
Specific comments:page 1 line 1: What is "The oceanic region at the terminus of the tidewater glacier"?
page 1 line 8: Why "ice-sheet melting" in particular in this context?
page 1 lines 8-9: Why do you refer to "polar ice sheets"?
page 1 line 11: Ice loss takes place at the glacier terminus, not near the glacier front
page 1 line 14: up to
page 1 line 16-17: of frontal ablation
page 1 line 17: What "topological morphology"? Could you please elaborate on that?
page 1 line 19: Is Vishnu et al., 2023 the best citation here? Were there no previous works on this subject, such as works by Erin Petit and her team, for example, or even older articles?
page 1 line 21: I find the auto-citation rate impressive, and frankly unacceptable. I have no access to Vishnu et al., 2024 (submitted to Science Advances). Please eliminate this reference.
page 2 line 26: Why do you mention the grounding line in this context?
page 2 line 35: As already stated above, the term "ablation" (unqualified) refers to total or surface ablation (Cogley et al., 2011). Therefore, the reader might expect a description of a robot that is designed to monitor surface ablation, which would require a completely different setup. I suggest rewording the robot name.
page 2 line 43-44: Please rewrite this sentence eliminating brackets
page 3 line 60: Around 83?
page 3 line 64: Is this application designed only for smartphones?
page 3 line 83: chance -> risk
page 5 Figure 2: Provide imagery acquisition dates, scale bar is missing
page 5 line 91: The correct place names are: Hansbreen (https://placenames.npolar.no/placename/53109416-bf7b-5e1d-86f1-768ef97a9dca) and Paierlbreen (https://stadnamn.npolar.no/Paierlbreen/Svalbard/5941fdba-64f4-5273-b0b6-9925db17a3f2)
page 5 lines 99-100: Please rephrase this sentence
page 6 line 128: Numbering is missing (2.) here and in the following lines
page 6 lines 133-134: Please rewrite this sentence eliminating brackets
page 6 line 136: infrared light source
page 7 Figure 3: panel a) is missing a label and the plot is unclear
page 7 lines 138-140: How would you estimate the size distribution from such imagery (upwards looking)?
page 8 line 146: "infrequently studied region" - please rephrase
page 9 line 178: "Improvisations"?
page 9 lines 195-200: How about the acoustically active depth at other sites?
page 9 line 201: What voltage?References:
Cogley, J.G., R. Hock, L.A. Rasmussen, A.A. Arendt, A. Bauder, R.J. Braithwaite, P. Jansson, G. Kaser, M. Möller, L. Nicholson and M. Zemp, 2011, Glossary of Glacier Mass Balance and Related Terms, IHP-VII Technical Documents in Hydrology No. 86, IACS Contribution No. 2, UNESCO-IHP, ParisCitation: https://doi.org/10.5194/egusphere-2024-32-RC1 -
RC2: 'Comment on egusphere-2024-32', Anonymous Referee #2, 16 Apr 2024
Brief communication “A low-cost surface vehicle for studying the near-terminus region at tidewater glaciers” by Hari Vishnu and others.
- General comments
This paper reports the application of a commercially available portable unmanned water surface vehicle for measurements in front of a tidewater glacier. The region near the calving front is a key to understanding ice-ocean interaction, but in-situ measurements are sparse because the region is difficult to approach. The use of an unmanned water vehicle is a solution to perform ocean measurements and such measurements have been reported in several glaciers. The authors use an inexpensive unmanned vehicle with some customisation of both hardware and software. The author’s interest is underwater acoustic measurement and CTD profiling, which were performed by mounting sensors on the vehicle and by towing a float equipped with instruments.
In general, the provided information is useful for readers planning a similar observation. The text is clearly and plainly written. My only concern is the novelty and significance of the device and procedure, which are required for publication as a journal article. Among the three categories of Brief Communications of The Cryosphere, the subject reported in the manuscript is relevant with “report new developments, significant advances, and novel aspects of experimental and theoretical methods and techniques which are relevant for scientific investigations within the journal scope” (https://www.the-cryosphere.net/about/manuscript_types.html). In-situ observation near the calving front is difficult, but already been reported in more than a few studies. Similar and more robust unmanned devices have been used in the previous studies. Something new about the device used in this study is its low cost. I agree that an inexpensive instrument helps research, but I am afraid that reporting a field test of a commercially available instrument does not meet the standard of the journal. It should be decided by the editorial team, but I expect more novelty in a paper published in The Cryosphere. I understand that the authors collected data from the operation of the device, which I assume will be published elsewhere. The material presented here may fit better as the methodology or supplementary information of such a publication.
- Specific comments:
Line 6: What do you mean by “even at”?
Line 26: Consider omitting “near the grounding line” because it is not relevant here.
Line 64: Is “Chasing cellphone app” the same application as mentioned in Line 53?
Figure 1: Please provide the length of the device as a scale of the images. Please also enlarge the instruments, particularly (d) and (e). In (d), it is not sure if the instruments are directly under the ice hang.
Figure 2: Provide a scale and date of acquisition of the background image.
Figure 3: Provide scales to the images.
Line 198: What do you mean by “maximum acoustically active depth”? How do you find that depth?
Figure B2: Please indicate in the figure where are the hydrophone and CTD.
Showing a more technical photograph and/or sketch of the vehicle is helpful.
Citation: https://doi.org/10.5194/egusphere-2024-32-RC2
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