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Record W7027763291

Drone-based ground-penetrating radar for glaciological applications

2024· dissertation· en· W7027763291 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

aboutThe title or abstract carries a Canadian signal from the geographic lexicon.
no affNo Canadian affiliation: this work is invisible to an affiliation-only frame.
No Canadian affiliation. An affiliation-only frame, the usual design, would never have seen this work. It is one of the works that make the case for inverting the frame.

Bibliographic record

VenueIRIS · 2024
Typedissertation
Languageen
FieldEngineering
TopicGeophysical Methods and Applications
Canadian institutionsnot available
Fundersnot available
KeywordsGround-penetrating radarRadarGlacierClimate changeSea iceGlaciologySynthetic aperture radar
DOInot available

Abstract

fetched live from OpenAlex

The cryosphere, which includes glaciers, ice sheets, ice shelves, sea ice, and permafrost, plays a crucial role in regulating the Earth’s climate, with significant impacts on ecosystems and human societies. Changes in the cryosphere, such as glacier retreat and ice shelf collapse, are key indicators of climate change, contributing to sea-level rise and accelerating global warming through feedback mechanisms. Consequently, understanding and modeling these changes is essential for predicting future climate impacts and developing effective adaptation and mitigation strategies. To model them consistently, in-situ data are necessary. Geophysics, particularly ground-penetrating radar (GPR), has been instrumental in studying the cryosphere’s internal structure. GPR can help to map ice thickness, estimate ice volume, detect water bodies, trace subglacial water flow, and more. Groundbased GPR surveys (i.e., by skis, snowmobile, or walking) offer high-resolution data but their coverage is usually spatially limited as they are labor-intensive and time-consuming, especially in difficult terrains. Airborne GPR surveys (i.e., on helicopter or airplane), though efficient, come at the cost of limited data density and resolution, and are expensive and polluting. This gap suggests the need for more adaptable methods of GPR data acquisition over glaciers. This thesis introduces a drone-based GPR system developed for acquiring highresolution and high-density 3D GPR data over alpine glaciers. The specification of each of its components as well as the survey methodology have been optimized to allow for efficient and safe data acquisitions. An 80-MHz antenna and a recording time of 2800 ns mean that depths of over 100 m can be reached in temperate ice. Also, differential GPS positioning assures accurate flight paths. The system was used to acquire a 3D dataset over the Otemma glacier in Switzerland, where 462 profiles were surveyed at a 1-m line spacing, totaling over 112 line-km of data covering an area of approximately 350 m x 500 m, in only four days. This proves the efficiency of our drone-based GPR system in acquiring such high-density 3D GPR data over glaciers. The accurate positioning capabilities of the drone-based GPR system makes precise repetitions of 3D acquisitions possible, further leading to high-resolution and high-density 4D GPR data. This was done over a near-terminus collapse feature at the Rhône glacier in Switzerland. The survey covers an area of approximately 100 m x 150 m, consists of over 100 parallel GPR lines with a 1-m lateral spacing, and was repeated four times between July and October 2022. Such acquisitions would not have been possible with conventional GPR methods. The data provide insights into the formation of the collapse feature and reveal the rapid temporal evolution of both a large subglacial air cavity and the associated subglacial water channels. To further test the capabilities of the drone-based GPR system in challenging environments, the system was brought to the Canadian High-Arctic, onWard Hunt Island located at 83°N. After optimizing the system’s performance for this polar setting and testing its capabilities in comparison with a snowmobile-towed GPR system, 3D GPR datasets were acquired over the Ward Hunt ice rise and ice shelf. Key findings include the detailed detection of internal ice layers within the ice rise following the seabed topography, the identification of a seabed step below the northern ice shelf that may have strengthened its stability during previous collapse events, and the confirmation of a mirror-symmetry between surface and basal undulations on the western ice shelf that supports theories of plastic deformation driven by pressure forces. By enabling the acquisition of large-scale, high-density, and high-resolution 3D and 4D GPR data, while also facilitating surveys in previously inaccessible areas that conventional surface-based GPR methods could not reach, the developed drone-based GPR system offers significant new opportunities for future cryospheric research.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Not applicable · Consensus signal: none
GenreCandidate signal: Methods · Consensus signal: none
Teacher disagreement score0.781
Threshold uncertainty score0.910

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.022
GPT teacher head0.309
Teacher spread0.288 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it