QBO modulation of the semiannual oscillation in MAECHAM5 and HAMMONIA
Bibliographic record
Abstract
The quasi‐biennial oscillation (QBO) signature in the equatorial upper stratosphere and mesosphere is analyzed from MAECHAM5 and HAMMONIA general circulation models. Our results show that this region is significantly influenced by the stratospheric QBO. In the upper stratosphere the QBO modulates the altitude of maximum descent of the stratospheric semiannual oscillation (SSAO) westerly phases. Our results also suggest that the QBO modulates the altitude of maximum descent and also the strength of the SSAO easterly phase. We explore the role of large‐scale and small‐scale waves and also momentum advection in the forcing of the QBO signature in the SSAO domain. The results show how the vertical propagation of the QBO signature to the middle and upper mesosphere depends on the vertical phase structure of the SAO and consequently on the seasonal cycle. During the solstices when MSAO westerlies prevail in the middle and upper mesosphere no QBO signature can be detected above the stratopause region. However, during the equinoxes, when MSAO easterlies dominate in the middle and upper mesosphere, the QBO signature extends throughout the mesosphere and low thermosphere. The QBO directly modulates MSAO easterlies by modifying the altitude at which they are generated in the upper mesosphere. A QBO signature is also detected on the MSAO westerly phase occurring in the mesopause region during the equinoxes.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".