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Record W4232773328 · doi:10.32920/ryerson.14648670

CN tower lightning flash characteristics based on high-speed imaging

2021· preprint· en· W4232773328 on OpenAlexaff
Ishmeen Sra

Bibliographic record

Venuenot available
Typepreprint
Languageen
FieldPhysics and Astronomy
TopicLightning and Electromagnetic Phenomena
Canadian institutionsMcMaster UniversityToronto Metropolitan University
Fundersnot available
KeywordsFlash (photography)TowerLightning (connector)MeteorologyPhysicsOpticsGeography

Abstract

fetched live from OpenAlex

The thesis emphasizes the analysis of fifty-eight flashes that struck the CN Tower during the last five years (2013-2017), based on video records of Phantom v5.0 digital high-speed imaging system, operating at 1 ms resolution. (A Sony HDR PJ790VB digital camera, operating at 16.67 ms resolution, provided a continuous recording of each CN Tower lightning storm.) It was observed that every recorded flash contained initial-stage current, confirming that all analyzed flashes were upward initiated. It was also observed that only 27 flashes out of the 58 contained return strokes. The number of strokes per flash varied between 1 and 9, with an average multiplicity of 2.16. The time variation of the channel luminosity of each flash was precisely analyzed for the characterization of flash components. A yearly statistical comparison regarding CN Tower lightning macroscopic (number of flashes, inter-flash times and flash durations) and microscopic (initial-stage current durations, number of the return strokes per flash, M-components and inter-stroke times) characteristics was conducted. The analysis of these extensive data (2013-2017) clearly showed that the 50% cumulative probability distribution (CPD) of flash duration in in 2017 was found to be the largest in comparison with other data (2013-2016). Whereas, the 50% CPD of inter-flash time duration in 2015 was the shortest. Furthermore, the 2014 data showed the longest 50% CPD of the initial-stage current duration as well as the inter-stroke time duration. In 2016, one flash was found to contain the highest number of return strokes. 2015 was distinguished by having the longest 50% CPD of the continuing current duration. It was also noted that two significantly major storms were captured during the nights of September 5, 2014 and September 4, 2017. During the storm of September 5, 2014, the CN Tower imaging systems recorded 13 flashes. The storm lasted for 111.4 minutes, resulting on average a flash to the tower every 9.28 minutes. Whereas, the September 4, 2017 storm continued for 49.35 minutes, producing 11 flashes for the tower every 4.9 minutes. The characterisation of CN Tower lightning is pivotal to the protection of tall structures against lightning hazards. It’s worth mentioning that flashes with longer flash duration, containing high number of return strokes and have shorter inter-stroke time durations pose severe threats to tall structures, electrical and communication systems

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.

How this classification was reachedexpand

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 categoriesMeta-epidemiology (narrow), Insufficient payload (model declined to judge)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.444
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0010.000
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0010.000
Open science0.0000.000
Research integrity0.0000.001
Insufficient payload (model declined to judge)0.0050.000

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 head0.006
GPT teacher head0.211
Teacher spread0.205 · 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

Classification

machine, unvalidated

Machine predicted; a candidate call from one teacher head, not a consensus.

Study designSimulation or modeling
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations1
Published2021
Admission routes1
Has abstractyes

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