the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 02 Aug 2023
Measurement of spatio-temporal changes of cave ice using geodetic and geophysical methods: Dobšiná Ice Cave, Slovakia
Abstract. Dobšiná Ice Cave has attracted the attention of many researchers since its discovery more than 150 years ago. Although the cave is located outside the high-mountain area, it hosts one of the largest blocks of underground perennial ice. The topographic mapping of this unique UNESCO Natural Heritage site has led to several historical surveys. In the last decades of rapid climate change, this natural formation has been subject to rapid changes that are dynamically affecting the shape of the ice body. Not only increased precipitation, the rise in year-round surface temperatures, but also the gravity cause significant shape changes in the ice filling. This paper describes modern technological tools to comprehensively survey and evaluate interannual changes in both the floor and wall of the underground ice block. Technologies such as digital photogrammetry, in conjunction with precise digital tacheometry, make it possible to detect ice accumulation and loss, including the effect of sublimation due to airflow, as well as sliding movements of the ice block to the lower part of the cave. In the last two years, geophysical methods (microgravimetry and ground penetrating radar) have been added to determine the thickness of the floor ice in the upper parts of the cave due to the complexity of the measurements. The paper not only highlights the current technological possibilities but also points out the limitations of these technologies and then sets out solutions with a proposal of technological procedures for obtaining accurate geodetic and geophysical data.
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RC1: 'Comment on tc-2023-110', Anonymous Referee #1, 18 Aug 2023
GENERAL COMMENTS
Dear Editor and Authors,
I am writing this review of the manuscript “Measurement of spatio-temporal changes of cave ice using geodetic and geophysical methods: Dobšiná Ice Cave, Slovakia”. I found the manuscript interesting and promising considering that the field is in continuous development and the study site is particularly challenging. That said, I was not expecting only partial results and discussions with almost no quantitative assessments after reading the title and the abstract.
In its current state, I believe this manuscript is not yet ready for publication since there is still ample room for improvement. Additionally, the most interesting part of the data, which, in my opinion, is the comparison of different methodologies or the investigation and quantification of changes measured using different methods, is not adequately presented. Moreover, some figures and paragraphs lack precision and can be better written (refer to specific comments provided below).
As the title mentions “Measurement of spatio-temporal changes of cave ice using geodetic and geophysical methods” I would expect to see results about this topic. I suggest either changing the title and the aims of the manuscript or improving it with the comparisons of the acquired data, making the measures of spatiotemporal changes an important part of it. Therefore, I find it strange that this is only presented as a partial analysis of the data with some results and almost no multi-temporal comparisons (the authors state that more data will be published in other papers: L360-361, L 406-407, L 415-416). I don't think these results should be in another paper, as they are the most interesting, at least in my opinion.
Additionally, I think that 20 figures are maybe too many, most of them can be integrated with each other and improved in quality. Some of them can be removed, especially when they are not adding value to the manuscript.
I suggest that major revisions are taken before proceeding further.
SPECIFIC COMMENTS
1 - Introduction
- The definition of ice cave is missing and there are no references to permafrost either, I’d suggest adding them to the introduction. To improve the introduction, I suggest also talking more about the climatic importance of ice in caves, mentioning a few more examples of significant literature.
- Some examples, but there are many more:
- Kern, Z., & Perşoiu, A. (2013). Cave ice - the imminent loss of untapped mid-latitude cryospheric palaeoenvironmental archives. Quaternary Science Reviews, 67, 1–7. https://doi.org/10.1016/j.quascirev.2013.01.008
- Luetscher, M., Jeannin, P. Y., & Haeberli, W. (2005). Ice caves as an indicator of winter climate evolution: A case study from the Jura Mountains. Holocene, 15(7), 982–993. https://doi.org/10.1191/0959683605hl872r
- Colucci, R. R., Fontana, D., Forte, E., Potleca, M., & Guglielmin, M. (2016). Response of ice caves to weather extremes in the southeastern Alps, Europe. Geomorphology, 261, 1–11. https://doi.org/10.1016/j.geomorph.2016.02.017
- Obleitner, F., & Spötl, C. (2011). The mass and energy balance of ice within the Eisriesenwelt cave, Austria. Cryosphere, 5(1), 245–257. https://doi.org/10.5194/tc-5-245-2011
- Colucci, R. R., & Guglielmin, M. (2019). Climate change and rapid ice melt: Suggestions from abrupt permafrost degradation and ice melting in an alpine ice cave. Progress in Physical Geography, 43(4), 561–573. https://doi.org/10.1177/0309133319846056
- Racine, T. M. F., Reimer, P. J., & Spötl, C. (2022). Multi-centennial mass balance of perennial ice deposits in Alpine caves mirrors the evolution of glaciers during the Late Holocene. Scientific Reports, 12(1). https://doi.org/10.1038/s41598-022-15516-9 - When mentioning the inter-annual variations studies from digital photogrammetry and laser scanning I would add the following works, that should be taken into consideration also during the rest of the manuscript:
- For Laser Scanning: Šupinský et al., 2019, that is already mentioned but I would give it more importance as its focused on ice cave topic and is introducing a further step comparing multi-temporal data of ice in caves. This work can also be used as reference for how to compare multi-temporal point clouds.
- For Structure from Motion: Securo, A., Forte, E., Martinucci, D., Pillon, S., & Colucci, R. R. (2022). Long-term mass-balance monitoring and evolution of ice in caves through structure from motion–multi-view stereo and ground-penetrating radar techniques. Progress in Physical Geography: Earth and Environment, 46(3), 422–440. https://doi.org/10.1177/03091333211065123 - I disagree with the sentence: “modern geodetic and geophysical tools after 2010 provide quite different qualitative results” because the beforementioned works provide also quantitative results.
- Ground Penetrating Radar has already been widely used for surveying ice caves as the published literature shows, I would add some noticeable examples about the topic:
- Colucci RR, Forte E and Fontana D (2014) Characterization of two permanent ice cave deposits in the Southeastern Alps (Italy) by means of ground penetrating radar (Gpr). In: VI International Workshop on Ice Caves (IWIC), Turin, Italy, September 2014, pp. 33–39. DOI: 10.13140/2.1.1343.1041.
- Gómez Lende, M., Serrano, E., Bordehore, L. J., and Sandoval, S. (2016) The role of GPR techniques in determining ice cave properties: Peña Castil ice cave, Picos de Europa. Earth Surf. Process. Landforms, 41: 2177–2190. doi: 10.1002/esp.3976
- Colucci, R. R., Fontana, D., Forte, E., Potleca, M., & Guglielmin, M. (2016). Response of ice caves to weather extremes in the southeastern Alps, Europe. Geomorphology, 261, 1–11. https://doi.org/10.1016/j.geomorph.2016.02.017
- Securo et al., 2022
- More others…
2 - Study Area
- Figure 1: Personally I would remove the world map, as there is already Slovakia with borders, in order to give more space to the useful maps, such as “b)”.
- I think Figure 7 with the Cave floorplan and cross sections with ice filling in the cave should be in the study area as it does not include any of the study’s work.
- If I correctly remember there’s an artificial structure made to retain cold air inside the cave that should, in my opinion, be mentioned in the manuscript if ice variations results are then discussed (not present in the current manuscript). Considering the technical focus of the paper this is just a suggestion, is not important to mention it if you do not discuss ice variations or temperatures.
- I would put L 90-95 part in the Study Area
3 - Materials and Methods
- L96: Chapter 3.1 is missing and should be this one. Chapter 3.2 and consequently change all the other sub-chapters.
- L132: Already written previously in the same chapter (e.g., L 111-112)
- I would add letters to the photos in Figure 5 and specifically mention them in the text or in the figure caption.
- It would be interesting to see the penetration of the laser beam (e.g., Figure 6) with different ice surfaces and related penetration distances, one case with one distance only may not be relevant. Furthermore, is there any way of filtering this data to improve accuracy despite laser penetration? Is there any example of this in the literature?
- When in L214-2015 the authors say, “Since the EMR penetrates the ice surface, the laser scanner survey was only used to model the overall shape of the cave itself, 215 not to model changes in the ice surface accurately”. Did you try to do any post-processing to the data? How did you evaluate the accuracy?
- In the SfM section I would add Securo et al. (2022) work as, to my knowledge, is the only one dealing with this topic inside ice caves. You can eventually add examples in caves with no ice as there are more.
- I think Structure from Motion processing described as “standard photogrammetric processing” requires a citation or further detail on the parameters used (e.g. the book from Carrivick: Structure from Motion in the Geosciences). Also, number of photos used, % of overlap during acquisition, and many more parameters are not present in the manuscript so this process is not really clear and reproducible.
- When you mention, in chapter 3.6, “monitored semi-annually” what do you specifically mean? Do you have multiple surveys taken more times each year? If yes, specify. It’s not very clear to me.
- The entire paragraph 3.7 (L256-270) on geophysical methods is superfluous and can be summed up without losing any key information in the last sentence. I would personally shorten it and leave the 2 sub-chapters 3.7.1 and 3.7.2 that are more important. If you think it must be there, please improve its content. An example could be distinguishing between potential and direct geophysical methods also, which was not done.
- About the use of Ground Penetrating Radar: I think one short profile in such a cave is not useful to do any kind of analysis as can lead to erroneous conclusions, being only partial. GPR in ice in caves has already been used successfully so there is no need to prove it a valid technique. Instead, it could have been useful to have more profiles. Considering the entire work, I see the GPR part as an extra that is not leading anywhere and I suggest its removal, or the addition of more profiles and processing, if these are somehow available from the cave.
- If you do not remove it I would mention some references from works dealing with GPR inside ice caves or in other similar settings.
4 – Results
- I found that having so many methods without comparing their precision is not very useful overall. Can you improve this or is it not among the aims of this work? Again, I found this would improve the quality of the manuscript.
- L358 “By comparing these results from individual epochs, we are able to determine changes in the ice filling over time.” There is currently no information about this in the results except for Digital tacheometry (but in Discussion).
- After reading “Given the complexity of the issue and the amount of data, we provide a partial analysis of results for the 2018-2023 epochs only for the first two photogrammetric sites.” I expected to see a partial analysis or at least some results from it. The only results I see now about this method are related to the effect of cross-polarization during SfM acquisition.
- Chapter 4.5 is not really a result in my opinion, it’s more a test of the methodology, which has already proven to be effective in these contexts and for these purposes.
- From Figure 17b I see only hyperboles with an estimated value of 0.16, is this the case of all of them or it’s just in this picture?
5 - Discussions
- Figure 18 should be in the results and not in the discussion.
- “Detailed inter-annual and inter-semi-annual (seasonal) measurements of the change in floor ice height will be analyzed in a separate paper.” I think this makes the actual work presented here less interesting, as no proof is reported about the precision of the methodology nor is any comparison among methods.
- About Figure 19 and the point cloud comparison: what technique has been used? Why this is in the discussion and not the results? What is the error in the alignment between the two-point clouds? Are we sure that changes below 10 cm can be correctly assessed or a significant % of them is also due to the errors? The methods used for comparing the point clouds should be mentioned better.
- The caption of Figure 19 starts with the same caption of Figure 15. Should be adjusted.
- Considering that this is a tunnel and therefore an “almost closed” shape, maybe you can calculate volume differences using the 3D mesh and its inner volume.
- L428 “The blank parts of the difference model represent parts with changes larger than 10 cm.”. Why these changes have not been quantified? As a reader, I thought they were a no-data area coming from the SfM reconstruction.
- If the ice screw of Figure 20 is in the same area surveyed in 2018 and 2023 with SfM, are the values of the SfM comparisons similar to the one observed in the screw? What is the difference between the two?
- I feel there was no need to prove GPR suitable for this kind of analysis as it’s already widely reported in the literature. For micro-gravimetry maybe you can discuss more the results?
- L447-554 are mostly methods and should be in that chapter.
- “GPR was also used in combination with SfM-photogrammetry to describe the topography and ice thickness and determine the volume changes of a glacier in Greenland.”. Despite the mentioned work being valuable, I found the applications of SfM-GPR presented in ice caves environment in Securo et al. (2022) much closer to this topic compared to Greenland local glaciers.
- In the final part of the discussion, you should mention the studies that already demonstrated what this paper states, as this is not the first case study using these techniques. It may be useful to compare what was achieved in this paper with Supinsky et al. (2019) and Securo et al. (2022) or with other works dealing with these topics in slightly different environments.
6 – Conclusions
- This entire part should be adjusted according to the rest of the modifications.
Citation: https://doi.org/10.5194/tc-2023-110-RC1 -
RC2: 'Comment on tc-2023-110', Anonymous Referee #2, 06 Sep 2023
Summary:
The authors present measurements processes with different geodetic and geophysical methods for the Dobšiná Ice cave. However, the abstract is more like the introduction for this manuscript, not including any analysis with quantification about the spatio-temporal changes about this ice cave, not really reflecting what the title implied. Based on the current status about this manuscript, I am not sure it fits the scope of The Cryosphere.
Major:
- The Introduction section is more like the history of this ice cave, and the following section about “study area” and “Material and methods”, could also be one part of the Introduction or be separate more in orderliness. I think the audiences are more curious about how people are surveying the cave, not the timeline for the development of the “geodetic and geophysical surveys”. The authors could reorganize the beginning part.
- For each section, like section 4. Results. Each sub section’s title could be revised to a clearer title to fit the section subject.
Minor:
Line 89 There is not Section 3.1 in the manuscript.
Line 159-161. Figure 8 should be mentioned before Figure 9.
Line 193-194. What result about the digital tacheometry measurement results would be shown in this manuscript?
Line 218 and Line 230. The Structure-from-Motion (SfM) is repeated.
Line 271 Since the Section 3.7 only includes sub section 3.7.1, maybe they could just combine together.
Line 393. Authors Morard et al., (2010), typo?
Line 422 and Line 426, it seems like you interpret the figure content in the same way.
Line 425 and Line 428, be constant to “approx. 5-10 cm” or “in the range of 0 – 10 cm”.
Line 431 an ice loss of -9 m3 -> an ice loss of 9 m3?
Line 435 2,5 cm->2.5 cm?
The reference styles are quite different from each other.
Figures:
Figure 5. It could be better with a scale for these sub-figures, probably similar to the other figures as well.
Captions for each figure could be modified in more detail.
Figure 10. (a)(b) could be clearer or united with the entire manuscript.
Figure 11. Normally we use “Locations”? and the label for the sub figure could be united with other figures.
Figure 17. figure(a) is so blurry and hard to read.
Figure 18. could be better in the caption to tell the reading the profiles’ location shown in Figure 13 or in the manuscript.
Figure 20. What do you mean by “spatial changes” represented here with the red arrow lines?
Citation: https://doi.org/10.5194/tc-2023-110-RC2
Status: closed
-
RC1: 'Comment on tc-2023-110', Anonymous Referee #1, 18 Aug 2023
GENERAL COMMENTS
Dear Editor and Authors,
I am writing this review of the manuscript “Measurement of spatio-temporal changes of cave ice using geodetic and geophysical methods: Dobšiná Ice Cave, Slovakia”. I found the manuscript interesting and promising considering that the field is in continuous development and the study site is particularly challenging. That said, I was not expecting only partial results and discussions with almost no quantitative assessments after reading the title and the abstract.
In its current state, I believe this manuscript is not yet ready for publication since there is still ample room for improvement. Additionally, the most interesting part of the data, which, in my opinion, is the comparison of different methodologies or the investigation and quantification of changes measured using different methods, is not adequately presented. Moreover, some figures and paragraphs lack precision and can be better written (refer to specific comments provided below).
As the title mentions “Measurement of spatio-temporal changes of cave ice using geodetic and geophysical methods” I would expect to see results about this topic. I suggest either changing the title and the aims of the manuscript or improving it with the comparisons of the acquired data, making the measures of spatiotemporal changes an important part of it. Therefore, I find it strange that this is only presented as a partial analysis of the data with some results and almost no multi-temporal comparisons (the authors state that more data will be published in other papers: L360-361, L 406-407, L 415-416). I don't think these results should be in another paper, as they are the most interesting, at least in my opinion.
Additionally, I think that 20 figures are maybe too many, most of them can be integrated with each other and improved in quality. Some of them can be removed, especially when they are not adding value to the manuscript.
I suggest that major revisions are taken before proceeding further.
SPECIFIC COMMENTS
1 - Introduction
- The definition of ice cave is missing and there are no references to permafrost either, I’d suggest adding them to the introduction. To improve the introduction, I suggest also talking more about the climatic importance of ice in caves, mentioning a few more examples of significant literature.
- Some examples, but there are many more:
- Kern, Z., & Perşoiu, A. (2013). Cave ice - the imminent loss of untapped mid-latitude cryospheric palaeoenvironmental archives. Quaternary Science Reviews, 67, 1–7. https://doi.org/10.1016/j.quascirev.2013.01.008
- Luetscher, M., Jeannin, P. Y., & Haeberli, W. (2005). Ice caves as an indicator of winter climate evolution: A case study from the Jura Mountains. Holocene, 15(7), 982–993. https://doi.org/10.1191/0959683605hl872r
- Colucci, R. R., Fontana, D., Forte, E., Potleca, M., & Guglielmin, M. (2016). Response of ice caves to weather extremes in the southeastern Alps, Europe. Geomorphology, 261, 1–11. https://doi.org/10.1016/j.geomorph.2016.02.017
- Obleitner, F., & Spötl, C. (2011). The mass and energy balance of ice within the Eisriesenwelt cave, Austria. Cryosphere, 5(1), 245–257. https://doi.org/10.5194/tc-5-245-2011
- Colucci, R. R., & Guglielmin, M. (2019). Climate change and rapid ice melt: Suggestions from abrupt permafrost degradation and ice melting in an alpine ice cave. Progress in Physical Geography, 43(4), 561–573. https://doi.org/10.1177/0309133319846056
- Racine, T. M. F., Reimer, P. J., & Spötl, C. (2022). Multi-centennial mass balance of perennial ice deposits in Alpine caves mirrors the evolution of glaciers during the Late Holocene. Scientific Reports, 12(1). https://doi.org/10.1038/s41598-022-15516-9 - When mentioning the inter-annual variations studies from digital photogrammetry and laser scanning I would add the following works, that should be taken into consideration also during the rest of the manuscript:
- For Laser Scanning: Šupinský et al., 2019, that is already mentioned but I would give it more importance as its focused on ice cave topic and is introducing a further step comparing multi-temporal data of ice in caves. This work can also be used as reference for how to compare multi-temporal point clouds.
- For Structure from Motion: Securo, A., Forte, E., Martinucci, D., Pillon, S., & Colucci, R. R. (2022). Long-term mass-balance monitoring and evolution of ice in caves through structure from motion–multi-view stereo and ground-penetrating radar techniques. Progress in Physical Geography: Earth and Environment, 46(3), 422–440. https://doi.org/10.1177/03091333211065123 - I disagree with the sentence: “modern geodetic and geophysical tools after 2010 provide quite different qualitative results” because the beforementioned works provide also quantitative results.
- Ground Penetrating Radar has already been widely used for surveying ice caves as the published literature shows, I would add some noticeable examples about the topic:
- Colucci RR, Forte E and Fontana D (2014) Characterization of two permanent ice cave deposits in the Southeastern Alps (Italy) by means of ground penetrating radar (Gpr). In: VI International Workshop on Ice Caves (IWIC), Turin, Italy, September 2014, pp. 33–39. DOI: 10.13140/2.1.1343.1041.
- Gómez Lende, M., Serrano, E., Bordehore, L. J., and Sandoval, S. (2016) The role of GPR techniques in determining ice cave properties: Peña Castil ice cave, Picos de Europa. Earth Surf. Process. Landforms, 41: 2177–2190. doi: 10.1002/esp.3976
- Colucci, R. R., Fontana, D., Forte, E., Potleca, M., & Guglielmin, M. (2016). Response of ice caves to weather extremes in the southeastern Alps, Europe. Geomorphology, 261, 1–11. https://doi.org/10.1016/j.geomorph.2016.02.017
- Securo et al., 2022
- More others…
2 - Study Area
- Figure 1: Personally I would remove the world map, as there is already Slovakia with borders, in order to give more space to the useful maps, such as “b)”.
- I think Figure 7 with the Cave floorplan and cross sections with ice filling in the cave should be in the study area as it does not include any of the study’s work.
- If I correctly remember there’s an artificial structure made to retain cold air inside the cave that should, in my opinion, be mentioned in the manuscript if ice variations results are then discussed (not present in the current manuscript). Considering the technical focus of the paper this is just a suggestion, is not important to mention it if you do not discuss ice variations or temperatures.
- I would put L 90-95 part in the Study Area
3 - Materials and Methods
- L96: Chapter 3.1 is missing and should be this one. Chapter 3.2 and consequently change all the other sub-chapters.
- L132: Already written previously in the same chapter (e.g., L 111-112)
- I would add letters to the photos in Figure 5 and specifically mention them in the text or in the figure caption.
- It would be interesting to see the penetration of the laser beam (e.g., Figure 6) with different ice surfaces and related penetration distances, one case with one distance only may not be relevant. Furthermore, is there any way of filtering this data to improve accuracy despite laser penetration? Is there any example of this in the literature?
- When in L214-2015 the authors say, “Since the EMR penetrates the ice surface, the laser scanner survey was only used to model the overall shape of the cave itself, 215 not to model changes in the ice surface accurately”. Did you try to do any post-processing to the data? How did you evaluate the accuracy?
- In the SfM section I would add Securo et al. (2022) work as, to my knowledge, is the only one dealing with this topic inside ice caves. You can eventually add examples in caves with no ice as there are more.
- I think Structure from Motion processing described as “standard photogrammetric processing” requires a citation or further detail on the parameters used (e.g. the book from Carrivick: Structure from Motion in the Geosciences). Also, number of photos used, % of overlap during acquisition, and many more parameters are not present in the manuscript so this process is not really clear and reproducible.
- When you mention, in chapter 3.6, “monitored semi-annually” what do you specifically mean? Do you have multiple surveys taken more times each year? If yes, specify. It’s not very clear to me.
- The entire paragraph 3.7 (L256-270) on geophysical methods is superfluous and can be summed up without losing any key information in the last sentence. I would personally shorten it and leave the 2 sub-chapters 3.7.1 and 3.7.2 that are more important. If you think it must be there, please improve its content. An example could be distinguishing between potential and direct geophysical methods also, which was not done.
- About the use of Ground Penetrating Radar: I think one short profile in such a cave is not useful to do any kind of analysis as can lead to erroneous conclusions, being only partial. GPR in ice in caves has already been used successfully so there is no need to prove it a valid technique. Instead, it could have been useful to have more profiles. Considering the entire work, I see the GPR part as an extra that is not leading anywhere and I suggest its removal, or the addition of more profiles and processing, if these are somehow available from the cave.
- If you do not remove it I would mention some references from works dealing with GPR inside ice caves or in other similar settings.
4 – Results
- I found that having so many methods without comparing their precision is not very useful overall. Can you improve this or is it not among the aims of this work? Again, I found this would improve the quality of the manuscript.
- L358 “By comparing these results from individual epochs, we are able to determine changes in the ice filling over time.” There is currently no information about this in the results except for Digital tacheometry (but in Discussion).
- After reading “Given the complexity of the issue and the amount of data, we provide a partial analysis of results for the 2018-2023 epochs only for the first two photogrammetric sites.” I expected to see a partial analysis or at least some results from it. The only results I see now about this method are related to the effect of cross-polarization during SfM acquisition.
- Chapter 4.5 is not really a result in my opinion, it’s more a test of the methodology, which has already proven to be effective in these contexts and for these purposes.
- From Figure 17b I see only hyperboles with an estimated value of 0.16, is this the case of all of them or it’s just in this picture?
5 - Discussions
- Figure 18 should be in the results and not in the discussion.
- “Detailed inter-annual and inter-semi-annual (seasonal) measurements of the change in floor ice height will be analyzed in a separate paper.” I think this makes the actual work presented here less interesting, as no proof is reported about the precision of the methodology nor is any comparison among methods.
- About Figure 19 and the point cloud comparison: what technique has been used? Why this is in the discussion and not the results? What is the error in the alignment between the two-point clouds? Are we sure that changes below 10 cm can be correctly assessed or a significant % of them is also due to the errors? The methods used for comparing the point clouds should be mentioned better.
- The caption of Figure 19 starts with the same caption of Figure 15. Should be adjusted.
- Considering that this is a tunnel and therefore an “almost closed” shape, maybe you can calculate volume differences using the 3D mesh and its inner volume.
- L428 “The blank parts of the difference model represent parts with changes larger than 10 cm.”. Why these changes have not been quantified? As a reader, I thought they were a no-data area coming from the SfM reconstruction.
- If the ice screw of Figure 20 is in the same area surveyed in 2018 and 2023 with SfM, are the values of the SfM comparisons similar to the one observed in the screw? What is the difference between the two?
- I feel there was no need to prove GPR suitable for this kind of analysis as it’s already widely reported in the literature. For micro-gravimetry maybe you can discuss more the results?
- L447-554 are mostly methods and should be in that chapter.
- “GPR was also used in combination with SfM-photogrammetry to describe the topography and ice thickness and determine the volume changes of a glacier in Greenland.”. Despite the mentioned work being valuable, I found the applications of SfM-GPR presented in ice caves environment in Securo et al. (2022) much closer to this topic compared to Greenland local glaciers.
- In the final part of the discussion, you should mention the studies that already demonstrated what this paper states, as this is not the first case study using these techniques. It may be useful to compare what was achieved in this paper with Supinsky et al. (2019) and Securo et al. (2022) or with other works dealing with these topics in slightly different environments.
6 – Conclusions
- This entire part should be adjusted according to the rest of the modifications.
Citation: https://doi.org/10.5194/tc-2023-110-RC1 -
RC2: 'Comment on tc-2023-110', Anonymous Referee #2, 06 Sep 2023
Summary:
The authors present measurements processes with different geodetic and geophysical methods for the Dobšiná Ice cave. However, the abstract is more like the introduction for this manuscript, not including any analysis with quantification about the spatio-temporal changes about this ice cave, not really reflecting what the title implied. Based on the current status about this manuscript, I am not sure it fits the scope of The Cryosphere.
Major:
- The Introduction section is more like the history of this ice cave, and the following section about “study area” and “Material and methods”, could also be one part of the Introduction or be separate more in orderliness. I think the audiences are more curious about how people are surveying the cave, not the timeline for the development of the “geodetic and geophysical surveys”. The authors could reorganize the beginning part.
- For each section, like section 4. Results. Each sub section’s title could be revised to a clearer title to fit the section subject.
Minor:
Line 89 There is not Section 3.1 in the manuscript.
Line 159-161. Figure 8 should be mentioned before Figure 9.
Line 193-194. What result about the digital tacheometry measurement results would be shown in this manuscript?
Line 218 and Line 230. The Structure-from-Motion (SfM) is repeated.
Line 271 Since the Section 3.7 only includes sub section 3.7.1, maybe they could just combine together.
Line 393. Authors Morard et al., (2010), typo?
Line 422 and Line 426, it seems like you interpret the figure content in the same way.
Line 425 and Line 428, be constant to “approx. 5-10 cm” or “in the range of 0 – 10 cm”.
Line 431 an ice loss of -9 m3 -> an ice loss of 9 m3?
Line 435 2,5 cm->2.5 cm?
The reference styles are quite different from each other.
Figures:
Figure 5. It could be better with a scale for these sub-figures, probably similar to the other figures as well.
Captions for each figure could be modified in more detail.
Figure 10. (a)(b) could be clearer or united with the entire manuscript.
Figure 11. Normally we use “Locations”? and the label for the sub figure could be united with other figures.
Figure 17. figure(a) is so blurry and hard to read.
Figure 18. could be better in the caption to tell the reading the profiles’ location shown in Figure 13 or in the manuscript.
Figure 20. What do you mean by “spatial changes” represented here with the red arrow lines?
Citation: https://doi.org/10.5194/tc-2023-110-RC2
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