Mechanisms of core‐mantle angular momentum exchange and the observed spectral properties of torsional oscillations
Bibliographic record
Abstract
Torsional oscillations of the fluid core produce decadal variations in the Earth's magnetic field and in the length of day. The magnetic field variations can be used to infer the fluid velocity of the oscillations. An additional constraint is imposed by the length‐of‐day variations because coupling mechanisms are required to transfer angular momentum between the core and mantle. Proposed mechanisms included electromagnetic, topographic, and gravitational couplings. We make use of a finite volume model of the core‐mantle system to evaluate each of these mechanisms with respect to observed spectral properties of torsional oscillations. We find that the different coupling mechanisms have different spectral characters which may be useful in distinguishing their importance within the Earth's core‐mantle system. For reasonable values of core and mantle properties, gravitational coupling between the mantle and inner core is the candidate mechanism most likely to be able to reproduce all spectral features of the observed transfer of angular momentum between the core and mantle. Possible spatial distributions of the torsional oscillation excitation source are also investigated.
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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 | 0.000 |
| 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".