Layer-layer interactions in atmospheric, cryospheric, and stellar dynamics
Notice bibliographique
Résumé
Layer-layer interactions comprise some key scientific unknowns and uncertainties in regional and large-scale planetary climate models. My dissertation studies their behaviour with an aim to develop explanations for and improve representations of observed phenomena. I focus on three different systems: stratosphere-troposphere coupling, ice-sediment mechanics, and turbulence in velocity-layered stellar interiors. Three distinct manifestations of stratosphere-troposphere coupling are studied in this dissertation. First, evidence suggests that ozone depletion has driven changes in southern hemisphere tropical tropospheric width, motivating study of the width of the stratospheric tropics and potential metrics. In the second chapter, directly measured chemical tracers form a useful basis for stratospheric tropical width estimates and two new tracer-based metrics are developed. These metrics are applied to assess relationships between tropospheric and stratospheric width changes and to study stratospheric transport processes. Second, unanswered questions about the extent of stratospheric modulation and disruptions to it confound efforts to distinguish anthropogenic sources of trace gases, such as continued production that violate the Montreal Protocol, from natural processes. The third chapter studies seasonal synchronizations between the dominant mode of lower stratospheric variability on one-to-five-year timescales and advective contributions to temporal changes in N₂O and CFC-11. These synchronizations influence the abundance of chemical species in the atmosphere from the stratosphere to the surface. Third, the close association between lower stratospheric temperatures and upwelling facilitate inferring the injection of trace gases and aerosols into the stratosphere. In the fourth chapter, a regional study of the response of lower stratospheric temperatures above the Asian summer monsoon anticyclone is found to obey quasigeostrophic theory. Lower stratospheric monsoon temperatures from both radiosondes and reanalysis have been cooling over the observational record, suggesting enhanced upwelling through the monsoon anticyclone, and increased stratospheric dehydration. The second system this dissertation focuses on is layered viscous flow. The fifth chapter resents a theoretical and experimental study of two-layer viscous flows on inclined surfaces, commonly found in environmental and industrial flows. The general model reveals a rich variety of flow regimes for different modes of release. These phenomena are likely to underlie more complex examples of layered flows, for which the model and analytical inroads revealed here provide a basis for generalization. The sixth chapter is motivated by rapid ice flow including icestreams and glacier surge events, which are quasiperiodic fast flow episodes. Mechanisms for surge initiation remain unknown and debated. Here, evidence that many surge-type glaciers are underlain by layers of fine, deformable sediment spurs a stability analysis of the ice-sediment interface. The assessment reveals positive feedback loops and instability mechanisms between the subglacial sediment and overlying ice. The third layered phenomenon this dissertation addresses is stellar turbulence. Shear-driven turbulence in stratified stellar interiors provides an important source of vertical transport of heat, momentum, and chemical tracers. Motivated by numerical evidence of anisotropic flows, the seventh chapter presents a multiscale analysis that identifies turbulent behaviour regimes. The eighth and final chapter concludes this dissertation by presenting an outlook and possible directions for future research.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,002 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,001 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,001 | 0,001 |
| Communication savante | 0,002 | 0,002 |
| Science ouverte | 0,000 | 0,001 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».