Observations of Surf Beat Propagation and Energetics
Bibliographic record
Abstract
Near-bottom pressure and velocity, measured along a cross-shore transect extending from the shore to about 8-m water depth on a barred beach, are used to study the cross-shore propagation of surf beat and the associated cross-shore flux of surf beat energy. The dominant Empirical Orthogonal Functions (EOF's) of pressure fluctuations measured in less than 5 m depth at relatively low beat frequencies (0.005–0.025 Hz) had well developed nodes and antinodes, with ±π phase jumps at the nodes, suggestive of standing wave motions. The dominant EOF's of relatively high frequency surf beat (0.03–0.05 Hz) showed some nodal structure, but their phase increased approximately linearly with distance from the shore indicating net shoreward propagation. EOF's of combined pressure and cross-shore velocity fluctuations at beat frequencies showed a similar mixture of standing and progressive waves. Furthermore, phases between pressure and velocity components were close to ±π/2 at relatively low beat frequencies (< 0.25 Hz), as predicted by standing waves theories, but at higher beat frequencies (0.3–0.05 Hz) phases usually had magnitudes less than π/2, but significantly greater than zero, suggestive of mixed standing and shoreward progressive waves. Shoreward propagating surf beat carried a shoreward energy flux. During a storm, this shoreward flux was about half the flux that could have been carried if all surf beat propagated directly shorewards. The energy carried shoreward by propagating surf beat was lost either at the shoreface (for moderate waves) or on the offshore side of the bar (during a storm). On one occasion surf beat carried energy seawards outside the surf zone and shorewards inside the surf zone, consistent with theoretical models that predict surf beat forcing at the outer edge of the surf zone.
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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) | 0.001 | 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".