Overturning Strength of the Sub-Polar Gyre in the North Atlantic Ocean, within the GLORYS12 reanalysis model
Notice bibliographique
Résumé
The Earth’s climate is changing, due to global warming, impacting the ocean circulation around the world. As the ocean circulation distributes large amounts of energy around the world, this can alter climate drastically if changed. The Atlantic Meridional Overturning Circulation (AMOC) is a fundamental ocean component to comprehend climate change and further investigation enhances our capacity to predict it. The AMOC plays a pivotal role in regulating the ocean heat transport within the North Atlantic Ocean, influencing the climates of North America and Europe. This study centers its attention on the Sub-Polar Gyre (SPG), a critical region where the AMOC activity peaks. Within this region, this study aims to get a better understanding of the overturning dynamics of the SPG, on a seasonal and annual time scale. To achieve this, the reanalysis model GLORYS12 is used, which offers a detailed simulation of ocean dynamics spanning the period from 1993 to 2020. With its high-resolution, eddy-resolving capabilities, GLORYS12 is particularly well-suited for capturing the nuanced small-scale overturning processes associated with the AMOC. From these model data, the overturning is calculated from alongstream changes in boundary current transport divided in density classes. The analysis is performed for the entire SPG by dividing it into its major basins: the Iceland Basin, Irminger Sea, and Labrador Sea. Subsequently, the boundary currents of the SPG are further subdivided into seventeen individual segments, providing insights into how overturning dynamics vary along the SPG. The results reveal that the mean overturning strength in the SPG for 1993-2020 is 23.8 Sverdrups (106 m3/s (Sv)). The distribution in overturning strength between the basins is 41%, 29%, and 30% for the Iceland Basin, Irminger Sea, and Labrador Sea respectively. Furthermore, the results shows overturning occurs at increasingly higher densities, the further west you go. Each basin displays a pronounced seasonal pattern, with maximum overturning occurring in March and the minimum in September. On an inter-annual time scale, the overturning strength in both the Iceland Basin and Irminger Sea exhibits a decreasing trend of -0.04 and -0.02 Sv/year respectively, whereas the Labrador Sea has an increasing trend of 0.02 Sv/year over 1993-2020. A further division in shorter segments yields large spatial differences in overturning, both in overall strength and the distribution over density classes. However, these outcomes are less robust as flows are highly variable and numerical errors associated with the overturning calculations become more prominent. This also raises questions about the reliability of the assessment of overturning along segments from observations to determine the local overturning dynamics. In conclusion, this study leverages GLORYS12 for a detailed basin and segmented analyses to offer a comprehensive understanding of the AMOC within the SPG. The findings provide valuable insights into the AMOC’s long-term behavior, seasonal variations, annual trends, and high spatial variability. Using this increased understanding, future research can improve on why the AMOC behaves in the observed way, by analyzing the overturning dynamics sensitivity to oceanic and atmospheric conditions
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 | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,001 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,001 |
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 ».