Normal-incidence bottom and sub-bottom reflection in the Canada basin of the Arctic Ocean
Bibliographic record
Abstract
The normal-incidence reflection coefficient of a patch of seabed in the Arctic Ocean was analyzed using the signal from a source colocated with a vertical line array. A mooring in the Canada Basin of the Arctic Ocean in approximately 4000 m water depth, contained a sound source 54.7 m below the water surface and a vertical receiving array below it. The source transmitted a pulsed sine wave at nominally 35 Hz once every 3 days for over a year. Bottom and sub-bottom reflected signals were clearly detected. The baseband demodulated signals were recorded and used in the analysis. The results showed that the bottom reflection was very stable at an average reflection loss of 13.5 dB, with an annual sinusoidal variation of 0.15 dB. Three sub-bottom returns were detected. The first is likely a bottom-simulating reflector with significant phase reversal, probably due to free gas beneath a hydrate layer. Fluctuations in the first and second sub-bottom returns are likely due to the changing bubble population beneath the hydrate layer. The third sub-bottom return was very strong and highly variable in both arrival time and amplitude, indicating a very rough sediment-basement interface.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".