the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 12 Jan 2024
A new repository of electrical resistivity tomography and ground penetrating radar data from summer 2022 near Ny-Ålesund, Svalbard
Abstract. We present the geophysical data set acquired in the summer of 2022 close to Ny-Ålesund (Western Svalbard, Brøggerhalvøya peninsula – Norway) as part of the project ICEtoFLUX. The aim of the investigation is to characterize the role of groundwater flow in correspondence of the active layer as well as through and/or below the permafrost. The data set is composed of Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) surveys, which are well-known geophysical techniques for the characterization of glacial and hydrological processes and features. 18 ERT profiles and 10 GPR lines were acquired, for a total surveyed length of 9.3 km. The data have been organized in a consistent repository that includes both raw and processed (filtered) data. Some representative examples of 2D models of the subsurface are provided, that is, 2D sections of electrical resistivity (from ERT) and 2D radargrams (from GPR). These examples can support the identification of the active layer. The data set is of major relevance because there is little geophysical data published about the Ny-Ålesund area. Moreover, these geophysical data can foster multidisciplinary scientific collaborations in the fields of hydrology, glaciology, climate, geology, geomorphology, etc. The geophysical data are provided in a free repository and can be accessed at the repository under data doi (Pace et al., 2023, https://zenodo.org/doi/10.5281/zenodo.10260056).
- Preprint
(2012 KB) - Metadata XML
-
Supplement
(117198 KB) - BibTeX
- EndNote
Status: final response (author comments only)
-
RC1: 'Comment on essd-2023-461', Rachele Lodi, 06 Feb 2024
The article is appropriate to support the publication of the dataset. The authors used standard methods, well described and referenced. The data presented represent a novelty in the field, so that the potential application and correlation with direct investigations and researches conducted in the area appears obvious to the terrestrial permafrost scientific community.
The dataset is competitive and accessible via the given Zenodo identifier. The state of the art in data collection and processing is adequately described. The dataset is significant, useful and complete.
The dataset is usable in its current format and size. Adequate space is used to describe the data, their organisation and possible processing, including appropriate examples. The overall structure of the paper is well organised and clear. A minor revision of the language is suggested.
About uniqueness, costly data sets such the one supported by the authors are not easily replicable for financial reasons.
Variations in permafrost conditions due to climate change are strongly influencing Arctic hydrology, although the implications are not yet well understood. Such a dataset could help to better frame the high quality research area around Ny-Ålesund and open the way to advanced multidisciplinary knowledge. Some minor revisions are suggested in the Supplement document attached.-
AC3: 'Reply on RC1', Francesca Pace, 17 Apr 2024
Dear Rachele Lodi,
Thank you very much for the time you spent on our manuscript and for the useful comments. In the attached file, we provide responses to your comments/suggestions and point to the made changes in the revised manuscript.
Regards,
The authors
-
AC3: 'Reply on RC1', Francesca Pace, 17 Apr 2024
-
RC2: 'Comment on essd-2023-461', Anonymous Referee #2, 13 Mar 2024
The paper titled "A new repository of electrical resistivity tomography and ground penetrating radar data from summer 2022 near Ny-Ålesund, Svalbard" contributes interesting geophysical dataset to the scientific community, particularly from the Ny-Ålesund area, which has been lacking due to logistical challenges in remote polar regions. The dataset, comprising ERT and GPR surveys, provides an opportunity to deepen our understanding of subsurface dynamics in the Arctic. The dataset is easily accessible via the provided Zenodo identifier, and it is well-organized and user-friendly. However, while I acknowledge the dataset's potential relevance, further discussion regarding its implications, potential applications, and avenues for future research could enhance the value of this contribution and facilitate interdisciplinary collaborations. The current presentation resembles more of a technical report rather than a scientific discussion of dataset.
Abstract:
Incorporating a brief mention of specific findings or insights gained from the dataset, even if preliminary, would provide readers with an overview of the study's potential implications.
Introduction:
The introduction could benefit from expanding on other geophysical methods commonly used in Arctic environments, such as seismic and EMI, while discussing why certain methods were chosen by authors, and also addressing potential limitations or uncertainties associated with their applications in such regions. Additionally, previous geophysical studies in the region (if any) should be discussed to highlight the novel contributions of this new data repository. Furthermore, elaborating on how this dataset can contribute to addressing existing gaps in knowledge about groundwater flow dynamics, active layer and permafrost (the aim of paper as suggested by authors) in Arctic regions would contextualize its significance within the broader scientific community.
Study Area:
The authors have included numerous references to previous geophysical studies in this region within this section. In my view, this content would be better placed in the introduction to complete the literature review and further justify the necessity of this new geophysical data repository. Currently, the section presents a lengthy list of references without establishing a clear connection to how these studies are related to the better understanding of “study area”. On the other hand, the section lacks detailed and specific information regarding the characterization of the study area, which is essential in my opinion to justify the applied geophysical methodology and array configuration. For instance, while the aim of the investigation appears to be the characterization of groundwater flow in relation to the active layer and potentially through or below the permafrost, there is a notable absence of information concerning the permafrost, active layer dynamics, and groundwater in this section. Information regarding the expected spatiotemporal variability of the active layer, the nature of the permafrost (e.g., continuous or discontinuous) and it is extension, and climate data are absent! Information about climate data play a significant role in the dynamic interactions between groundwater, the active layer, and permafrost. Furthermore, the potential availability of borehole data in this region could provide valuable insights into permafrost conditions and potential degradation. Access to such information would enable readers to better understand the rationale behind the choice of geophysical methods and array design, particularly concerning the trade-off between resolution and depth of investigation and also interpretation of data and modelling results.
Geophysical Surveys:
The authors could provide additional insights into the rationale behind the chosen survey configurations, such as the use of electrode spacing of 1 and 10 meters. e.g. whether the smaller spacing is intended for active layer characterization and larger spacing for permafrost? Moreover, detailing the challenges encountered during the surveys using ERT and GPR conducted in this region, data noise and uncertainties, modelling error would not only assist researchers to understand the limitations of data but also benefit those engaged in geophysical prospecting in polar and remote areas for potential improvement.
ERT:
Further information regarding contact resistance data would be valuable if available. This could include typical values observed during ERT surveys, the efficacy of bentonite solution in mitigating contact resistance, and any experimentation with other alternatives such as salt water. Additionally, details on electrode type and dimension, the establishment of threshold values for contact resistance filtering, and the extent of data filtered based on each criterion (e.g., negative values, contact resistance, outlier) and in total would be useful. Such insights contribute to our understanding of best practices for ERT surveying and data processing in permafrost regions. See for example
Herring, T., Lewkowicz, A.G., Hauck, C., Hilbich, C., Mollaret, C., Oldenborger, G.A., Uhlemann, S., Calmels, F., Farzamian, M., Calmels, F., and Scandroglio, R. 2023. Best practices for using electrical resistivity tomography to investigate permafrost, Permafrost and Periglacial Processes, 34, 4, 494-512, https://doi.org/10.1002/ppp.2207.
While acknowledging that this is primarily a data-based publication, I suggest that the authors go a bit deeper into the interpretation of ERT examples. This includes presenting how resistive values are interpreted (based on available data), their lateral and vertical variability, quantifying average resistivity changes across different sites and depths of investigation, and exploring potential subsurface factors influencing and explaining variability. While direct measurements of electric resistivity in the investigated area seems not be available, some additional information such as borehole data (if available) can help with interpretations of resistivity data and facilitate broader utilization of this dataset.
GPR:
From the text It's unclear whether the surveys were conducted continuously or manually, and whether the antenna was pulled or measured at specified distances (for both antennas). Given that these antennas are not typically designed for rough terrains, it's worth discussing if the authors encountered any additional challenges during data collection and processing, particularly regarding ensuring proper surface contact and if those challenges impacted data quality.
Additionally, it's unclear whether the same processing steps discussed apply to both antennas or specifically to the 400 MHz frequency. Furthermore, there is an absence of example presentations of GPR data from the low frequency of 40 MHz. Incorporating such examples would offer a more comprehensive understanding of the collected GPR data and also comparison with deeper ERT surveys with 10m electrode spacing.
A preliminary interpretation of the GPR results presented in Figure 8 would be beneficial, particularly considering that the surveys were conducted in a piezometer area. I miss any information about piezometer area and if they are available and how they could guide on survey design and interpretations afterward.
Is there any available information from the site that could assist in estimating the dielectric constant, even if only roughly, to enable estimation of the depth of reflections? Alternatively, has there been any calibration conducted over known buried targets? Could piezometer data from the study area be used for this purpose?
MT:
The current statement about MT may not offer significant insight into the source of the problem. Thus, I recommend either including more information about the equipment, survey design, and even including datasets or removing this section and briefly mentioning it in the introduction.
Citation: https://doi.org/10.5194/essd-2023-461-RC2 -
AC1: 'Reply on RC2', Francesca Pace, 17 Apr 2024
Dear Rachele Lodi,
Thank you very much for the time you spent on our manuscript and for the useful comments. In the attahced file, we provide responses to your comments/suggestions and point to the made changes in the revised manuscript.
Regards,
The authors
-
AC2: 'Reply on RC2', Francesca Pace, 17 Apr 2024
Dear anonymous Reviewer2,
Thank you very much for the time you spent on our manuscript and for the useful comments. In the attached file, we provide responses to your comments/suggestions and point to the made changes in the revised manuscript.
Regards,
The authors
-
AC1: 'Reply on RC2', Francesca Pace, 17 Apr 2024
-
EC1: 'Comment on essd-2023-461', Baptiste Vandecrux, 18 Apr 2024
Dear Dr. Pace,
Thank you for your response to the reviewers and for the revised manuscript.
I want to come back to the reviewer's comment:
While acknowledging that this is primarily a data-based publication, I suggest that the authors go a bit deeper into the interpretation of ERT examples. This includes presenting how resistive values are interpreted (based on available data), their lateral and vertical variability, quantifying average resistivity changes across different sites and depths of investigation, and exploring potential subsurface factors influencing and explaining variability. While direct measurements of electric resistivity in the investigated area seems not be available, some additional information such as borehole data (if available) can help with interpretations of resistivity data and facilitate broader utilization of this dataset.
I do agree with this comment and I find that the added material in the discussion does not really provide more information, but rather a list of analysis that could be conducted on the data.
Please provide these interpretations as demanded by the reviewer.Since the motivation of the data is to document permafrost and groundwater at your study sites, please detail what (basic) information you already see in your data:
- What is the depth of the active layer
- What is the potential depth and extent of permafrost
- Is there any evidence of hydrological activitySince you have collected these data, you are also the most suited to answer those questions.
"Teasing" what you already see in the data will also increase the reuse of your dataset in the future:
- Hydrologists might want to know whether you see evidence of groundwater in your data, before they decide to reuse it or not
- Geomorphologists might want to hear about your permafrost characterisation (or what makes it impossible with the available data), so that they can design another survey, to be compared to yours.Additionally, please address the following minor comments:
- Please proof-read carefully the revised sections for other langage mistakes.
- change "thought for food" to "food for thought" in the third line of the discussion. This might be removed if these "food for thought" are being replaced by actual interpretations.
- l.166 "an amount of water larger the past is observed to melt and drain to the tongue of the glacier". Is there a word missing?
- l. 168 "abovementioned" change to "above-mentioned" - Figure 3, 8 and 11 should have larger text. Please provide plots with higher resolution and without background artefacts (gray background in figure 3 and line between panels in figure 11)
- Please label each panel in the multi-panel figure with (a), (b), (c)... Please mention these labels when describing each panel in the caption. Please use these labels in the text whenever a figure is mentioned: e.g. "we can see in fig3a that X and in fig3b that Y". For conciseness, please only show the figures/panels that are actively described in the text. If a figure/panel is an intermediate step but not a crucial result, or if it is just a "nice-to-have" illustration, please move it to the supplementary materials.
- Please add a depth scale (on the right side) to Figure 11 using your estimation of wave velocity. You here give one value. Should that value be used for all transects? Please repeat this estimation for each transect if necessary.
- You provide 5 references from T.I. Beka. One of them is a phd thesis: is there any information in the thesis that does not appear in the other peer-reviewed publications? If not, please prefer peer-reviewed sources. Is that the only team that has applied EMI in Svalbard? If not please diversify your sources.
- Thank you for the additional information about the mining activities and the springs. Please make clear whether your transects are located over mined channels. If they are not mapped, do you see any evidence of open channels at or nearby your transects? In the discussion, it seems very appropriate to discuss whether you see any evidence of water around Ester Springs.
Sincerely,
Baptiste VandecruxCitation: https://doi.org/10.5194/essd-2023-461-EC1 - Please proof-read carefully the revised sections for other langage mistakes.
Data sets
A new repository of electrical resistivity tomography and ground penetrating radar data from summer 2022 near Ny-Ålesund, Svalbard Francesca Pace, Andrea Vergnano, Alberto Godio, Gerardo Romano, Luigi Capozzoli, Ilaria Baneschi, Marco Doveri, and Alessandro Santilano https://doi.org/10.5281/zenodo.10260056
Viewed
| HTML | XML | Total | Supplement | BibTeX | EndNote | |
|---|---|---|---|---|---|---|
| 375 | 135 | 32 | 542 | 30 | 22 | 19 |
- HTML: 375
- PDF: 135
- XML: 32
- Total: 542
- Supplement: 30
- BibTeX: 22
- EndNote: 19
Viewed (geographical distribution)
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1