Source depth and array tilt effects on seabed inversion of ambient noise
Bibliographic record
Abstract
Ambient noise coherence between two vertically separated sensors in shallow water relates to the directionality of the noise field and is sensitive to the reflective properties of the surficial sediments. In earlier work, an energy-flux model was developed to calculate the noise coherence over a multilayered seabed; in this model the surface sources were assigned a frequency-independent dipole directivity pattern. The model was subsequently combined with a hybrid nonlinear inversion procedure to effectively search the space of geoacoustic properties that parametrize a multilayered seabed. In order to benchmark the energy-flux model against a wave-theoretical formulation, the issue of the unknown but finite source depth of the noise sources must be addressed. These near-surface sources result in a frequency-dependent beam pattern that is not dipolar above a few hundred hertz [M. J. Buckingham and N. M. Carbone, J. Acoust. Soc. Am. 102, 2637–2644 (1997)]. In this paper, we extend the energy-flux model to include the effect of finite source depth as well as sensor tilt on the observed directivity of the ambient noise field. These extra degrees of freedom are added to the search space of the inversion procedure and their influence on estimating seabed properties from noise coherence data is investigated.
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 imitationNot 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.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| 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 teacher head, 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".