Arctic polar vortex variability in the Canadian middle atmosphere model
Bibliographic record
Abstract
Arctic polar vortex variability in the Canadian Middle Atmosphere Model (CMAM) is documented.Two integrations of the CMAM are compared to assess the effects of parametrized non-orographic gravity waves on the frequency and timing of stratospheric sudden warmings (SSWs), as well as on the potential for polar stratospheric cloud (PSC) formation.The first integration does not include parametrized non-orographic gravity waves while the second integration does.The first integration captures the basic features of the observed northern hemisphere (NH) winter circulation although the polar night jet (PNJ) is significantly too weak and poleward shifted.Together with the weaker than observed PNJ are SSWs that occur too often and too early, resulting in an unrealistically low early to mid-winter potential for PSC formation.Whereas, by design, the inclusion of parametrized non-orographic gravity waves in the second integration significantly improves the southern hemisphere (SH) circulation, the strength of the NH PNJ is further reduced relative to the first integration, and the SSW frequency and PSC formation potential further degraded.Finally, the synoptic evolution and wavebreaking signature of the simulated and observed SSW events are compared through the application of a composite high resolution contour advection algorithm. RSUM [Traduit par la rdaction] La variabilit du tourbillon circumpolaire arctique dans le modle canadien de l'atmosphre moyenne (CMAM) est documente. Deux intgrations du CMAM sont compares afin d'valuer les effets des ondes de gravit non orographiques paramtres sur la frquence et le moment d'occurrence des rchauffements stratosphriques soudains (SSW) ainsi que sur le potentiel de formation de nuages stratosphriques polaires (PSC). La premire intgration n'inclut pas les ondes de gravit non orographiquesparamtres, tandis que la seconde les inclut.La premire intgration saisit les caractristiques fondamentales de la circulation hivernale observe dans l'hmisphre Nord quoique le courant-jet polaire (PNJ) soit dcidment trop faible et dvi vers le nord.Accompagnant le PNJ plus faible qu'observ, il y a les SSW qui se produisent trop frquemment et trop tt, ce qui entrane un faible potentiel non raliste pour la formation de PSC au dbut et au milieu de l'hiver.Alors que, par conception, l'inclusion d'ondes de gravit non orographiques paramtres dans la seconde intgration amliore sensiblement la circulation dans l'hmisphre Sud, la force du PNJ dans l'hmisphre Nord est rduite davantage relativement la premire intgration et la frquence de SSW ainsi que le potentiel de formation de PSC sont de nouveau diminus.Finalement, l'volution synoptique et la signature de bris d'ondes des vnements de SSW simuls et observs sont compares par l'application d'un algorithme combin d'advection de contours haute rsolution.
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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 | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.007 | 0.001 |
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".