Low-frequency bottom and subbottom reflections in the Arctic Ocean
Bibliographic record
Abstract
Using data recorded and made available by the Scripps Institution of Oceanography, acoustic bottom reflection beneath a mooring in the Canada Basin of the Arctic Ocean was measured over a period of 1 year. The data were collected at a mooring in a water depth of 4000 m, which contained a sound source and a vertical array of hydrophones. The latter was used to form up and down-looking end-fire arrays. Reflections from the bottom and three subbottom layers were detectable. The sound path between the array and the bottom was very stable consistent with a very homogeneous water mass below 400 m called the Canada Basin Deep Water. The normal bottom reflection loss was approximately 13.5 dB, with a small annual sinusoidal variation. The subbottom returns were less stable. The first subbottom return may be due to free gas beneath a stable hydrate layer. The third subbottom return was very strong and variable in both travel time and amplitude. [Work supported by the US Navy’s Office of Naval Research, Code 322OA, grant N00014-23-1-2522.]
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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 | 0.001 |
| 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".