the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
A self-sufficient mobile broadband seismological recording system for year-round operation in Antarctica
- 1Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
- 2Lippmann Geophysical Instruments (LGM), Schaufling, Germany
- 3Physics of Ice Climate and Earth, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
- 1Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
- 2Lippmann Geophysical Instruments (LGM), Schaufling, Germany
- 3Physics of Ice Climate and Earth, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
Abstract. Passive seismic measurements allow the study of the deeper earth beneath the thick Antarctic ice-sheet cover. Due to logistical and weather constraints, only a fraction of the area of the Antarctic ice sheet can be surveyed with long-term or temporary sensors. A fundamental limitation is the power supply and operation of the instruments during the polar winter. In addition, there is only a limited time window during the field seasons to deploy the stations over the year. Here we present a rapidly and simple deployable self-sufficient mobile seismic station concept. The station consists of different energy supply modules aligned according to the survey needs, measuring duration and survey aim. Parts of the concept are integrated into an already existing pool of mobile stations as well as in the seismological network of the geophysical observatory at Neumayer III Station. Other concepts and features are still under development. The overall goal is to use these temporary mobile arrays in regions where little is known about local and regional tectonic earthquake activity.
Alfons Eckstaller et al.
Status: final response (author comments only)
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RC1: 'Comment on gi-2022-4', Alex Brisbourne, 08 Apr 2022
Review of “A self-sufficient mobile broadband seismological recording system for year-round operation in Antarctica” by A. Eckstaller et al., 2022, Geoscientific Instrumentation
Alex Brisbourne, April 2022
Eckstaller et al. present an overview of their mobile seismic station system for use in the polar regions. The group have developed a relatively lightweight and mobile system for use in a modular manner with different seismic and recording systems. The manuscript covers concepts, requirements and solutions.
The paper is well written and easy to follow. It provides a lot of useful ideas and concepts which practitioners embarking on similar deployments will find useful to be highlighted prior to starting such projects and therefore forms a useful piece of work.
Major comments
The system has a lot of similarities with the IRIS Passcal system used for the Polenet Project which has become the standard for many deployments in Antarctica. However, it takes until the acknowledgements for this to be recognised. In addition, there is little mention in the introduction of Polenet or IRIS. For example, all the white circles on Fig. 1a are Polenet stations and the authors do a disservice to the work of these groups to have achieved the station coverage of West Antarctica that Figure 1 highlights. I would suggest a paragraph in the introduction covering: The IRIS Passcal system; the relationship between this system and the IRIS Passcal system and why the concept presented here I needed; the achievements of the Polenet project. Again, in section 4, I suspect that IRIS Passcal now have some impressive year-round data recovery rates. I would like to see these mentioned for comparison and perhaps some comments on how this work advances that of Passcal.
I feel that there are details missing that would make this a much more useful paper. A number of the statements are subjective. I would like to see a table of specifications for components listing power draw and weight for example and a way of understanding the relative power-cost of individual components (sensor and data logger are reported), such as the XEOS or Solar controller. How about example overall station weight/volume etc.
The title including “year-round” may be a stretch as it seems that this concept has yet to be fully established for year-round recording. Maybe that’s why the word operation is used? Perhaps a little disingenuous.
In many ways the manuscript leaves a lot of questions unanswered, mostly being why did the developers use this controller or that modem? Were other systems tested and ruled out? You could save future practitioners some effort by stating why these units were used over others (not necessarily having to publish manufacturer’s names).
Minor comments
- 2 and elsewhere – 3k seismometer – do you mean 3-Component?
- Table 1 – I am not sure I would call the table or column 2 “Instrument specifications”, it is more the model numbers. I do however feel that at some stage (probably in the appendix) more detailed specifications would be welcome, such as temperature rating, power draw etc).
- L108 – What is the power drain of the Morningstar 15L?
- L110 – Likewise, what is the power requirement of the XEOS over a season?
- L122 – can you quantify “high winds”?
- L159 – not sure what “into the drilling hole” means
- L173 – good to quote power drain in Ah or Ah/day
- L174 – it would be good to know how the overall power budget is distributed amongst the components.
- L194 – Again, IRIS Passcal have addressed and solved this issue in one way but it isn’t mentioned.
- L227 – another issue that could be highlighted is that wind strengths are highly variable spatially and in my experience the manufacturing tolerance of wind generators tends to be poorly managed so two adjacent supposedly identical units can respond differently to wind strength. Do the authors have any experience of this that could be included?
- L245 – do you mean discharging rather than charging?
- EC2: 'Reply on RC1', David Barclay, 23 Apr 2022
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RC2: 'Comment on gi-2022-4', Fabian Walter, 22 Apr 2022
This submission by Eckstaller et al. proposes technical solutions for deploying on-ice seismic broadband stations in Antarctica. The authors present a setup that solves some of the technical problems implied by the rough Antarctic environment and offer an outlook on future developments and additions to their system to tackle other challenges like limited sunlight during the Austral winter.The manuscript is clearly written and easy to follow. As someone who has installed seismometers in icy conditions throughout his scientific career, I welcome such a communication. Written and publically available documentation on technical details of instrument deployments can be extremely important for future projects and may make the difference between research success and failure. At the same time, I would encourage the authors to make some major modifications on how this material is presented. I detail these points of criticism below.Fabian Walter.MAJOR COMMENTSAn easily implemented though to me essential change would be not to mislead the reader in thinking that a technical solution to year-round broadband station deployment has been successfully tested. This is suggested in the title and the last paragraph of the introduction. In the final paragraph of the Discussion, the authors back down from this claim stating that bridging the winter gap was not yet the goal of this technical solution but is left for future efforts. This will likely annoy the reader who truly looks for useful information for his/her future deployment and feels encouraged by the abstract and introduction. At all parts of the manuscript, the reader should be clear on what this study is for. To my mind there is nothing wrong with presenting an intermediate step to an ideal broadband setup, but this has to be communicated from the beginning.My second point of major criticism is that the material tends to be presented as an experience report rather than a systematic evaluation of different options, which I would expect for a scientific paper. It would help to see more numbers, especially on power consumption, that were the basis for the hardware choices. See my specific comments below.Finally, I suggest providing more information on the Antarctic setting: Like I said, I have deployed many instruments on glacial ice myself, however, the majority was on ablation zones, which are ice-free in the summer. This is a very difficult environment, as well, although completely different from the Antarctic setting. For example, if the station is visited infrequently and rarely, which is the final goal of the author's set up, how do you deal with snow accumulation? Do the instruments have to be unburied and moved close to the snow surface regularly? Or is snow accumulation negligible at the locations and over the time scales of interest?SPECIFIC COMMENTSThe manuscript has a few typos and grammatical mistakes (in particular the use of past tenses) that should be corrected with a thorough proofread."Data" is plural.Line 37: rewrite: "However, there is little on ...".Line 53: "adequate capacity" should be defined.Line 75: "ice lying over solid rock": as opposed to what? Lying over subglacial till?Figure 2 and associated text: The wind battery box still seems an idea rather than an established solution. This should be made clear from the beginning of the manuscript. What is the difference between an equipment and an electronic box?Table 1: This table would strongly benefit from numbers, especially on power consumption or supply (which is given in the text for some elements). Such a concise presentation would be extremely useful for a reader interested in adopting the author's approach or parts of it.Lines 103-106: Here some numbers about the power consumption for different configurations would be more helpful than just specifying the authors' favorite choice.Figure 3A: Is the battery box associated with solar or wind power? Later from the text it is clear that it's the former, but it should also be stated in the figure or its caption.Line 152: As a non-expert I would expect a reference for this statement.Section 3.1.3: This paragraph is held rather general and superficial. Many readers would be interested at which temperature range or minimum temperature battery heating is worth it and when it costs more than it provides gains in terms of power supply. Ideally, this information should be given here and backed up with numbers, e.g., from test measurements.Line 157: Not sure what is meant by "which can switch 6 amperes of heating current".Line 167: What is meant by "switched opposite to each other"?Lines 174-175: What is meant by "cascading batteries"?Lines 184-185: This sentence reads more like an instruction manual than a scientific piece of text.Lines 194-195: Is this based on test measurements? Or is there a reference for this statement?Line 196: delete "additionally"Line 201: use of "huge" is awkward.Lines 210-211: Why can Li batteries not be recharged? Because of low temperatures?Lines 217: Which remaining energy?Line 218: "easily integrated" sounds a bit fuzzy. The reader is left wondering why then it hasn't been integrated (see following sentences).Lines 224-225: Why is the wind turbine installation so involved?Line 232: The use of adjectives like "careful" and "proper" weakens this part of the paper. More specifics would help.Line 241: Quantify "very low temperatures".Line 244: Is "mass" the right word here? Better "ground"?Section 4.3: A general remark: we also had big problems with static charge on Alpine glaciers. In the end we found it beneficial to make sure all station elements (sensor, digitizer, metal frames, ...) were connected and at the same potential. This solved most problems although no ground was available on the ice.Line 253: rewrite "partly very different"Line 255: "fast to deploy" with respect to what?Lines 274-278: Here the original goals are redefined. This has to be changed.Line 291: In this sentence the term "polar" or "on-ice" or something equivalent should appear.Lines 294-295: This statement is trivial.Lines 296-298: Perhaps it's worth considering that seismic records have high sampling rates and thus the setup could easily afford power supply for GPS, temperature gauges, and other environmental monitoring logging at lower sampling rates.General question: Would it be possible to stream data with this setup or is this more than an incremental step in power consumption?There are two sections 3.1.1. In general, I find this manucript contains many sub and sub-sub sections given its limited length.
- EC1: 'Reply on RC2', David Barclay, 23 Apr 2022
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RC3: 'Comment on gi-2022-4', Anonymous Referee #3, 27 Apr 2022
This work highlights an effort to develop robust seismic stations for Antarctica. As noted here and in previous work, operating seismic stations (or any other autonomous geophysical station) is challenging due to the environmental conditions, in particular the cold and dark. While all sharing of technological advancements are welcome, I feel that in this case, the authors have provided too few details to make the manuscript useful to the audience. I would encourage the authors to provide more information so that other researcher can more easily replicate their design. Below I have a few detailed comments.
Detailed Comments:
Line 58: Perhaps a bit picky, while -20 C to -40 C is certainly cold, I’m not sure it is “extreme” since a Nanometrics trillium posthole 120 can operate to -50 C.
Line 75: Mention that Neumeyer Station is on an ice shelf ( I had to look this up)
Line 93: Is it better to use the term Peli (or Pelican) case? A websearch for “Eurocase” doesn’t led to the product, I only got to the product page by search the model number included in table 1.
Line 93: I notice on the spec sheet for EU080060-5010 that a minimum temperature is -30 C, have the authors had experiences with this product at colder temperatures?
Line 110: More details on the XEOS XI-202 on the SeiDL Controller are needed? What exactly operations can they perform do? How much power do they consume?
Line 116/(table 1). What are the characteristics of the GPL31XT batteries that led the authors to choose them? What differentness them from other AGM batteries?
Line 123: Quantify high wind. I have seen many “mechanically robust” pieces of equipment blown apart by wind.
Line 124: I think the authors mean “Pladur Panel Alveo” when they say “Alveo”. When I do a web search for “Alveo” this is the only company that appears to make panels. More details one the exact nature of the panels would be nice as well.
Section3.1.1 and 3.2- I think more details are needed (wiring diagrams?) for these sections to be helpful to the reader or an engineer.
Section 4.1.1: A reader unfamiliar with Antarctic seismology may think this has not been successfully implemented when in fact the use of Li batteries have been the power stations for numerous experiments support the PASSCAL instrument facility (this is briefly mentioned in section 4.4). Thus, I think a reference to Hansen et al., 2015 (where the use of Li Batteries is explicitly stated) is needed in this section.
Section 4.1.2: More details are needed. I have talked to many people whom have had NO success with wind generators in Antarctica for various reasons (wind extremes, icing). If the authors are utilizing wind power successfully at VNA2 and VNA3 that is a great advance and I would like to know more! What are the temperature conditions? How much power is produced?
- EC3: 'Reply on RC3', David Barclay, 27 Apr 2022
Alfons Eckstaller et al.
Alfons Eckstaller et al.
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