Precipitation, moisture sources and transport pathways associated with summertime North Atlantic deep cyclones
Notice bibliographique
Résumé
Abstract. Extratropical cyclones are essential for redistributing moisture from lower latitudes to the poles, and are known for their ability to produce extreme precipitation. While wintertime extratropical cyclones have been studied in great detail, little is known about these systems in summer. Nevertheless, studying summer cyclones is particularly relevant in the context of climate change, as future warming is expected to increase atmospheric moisture while reducing baroclinicity. This makes present-day summer conditions an analogue for future winter cyclones and critical for understanding how summertime cyclones themselves may evolve in a warmer climate. Hence, the objective of this study is to improve our understanding of how summertime extratropical cyclones shape the characteristics of the water cycle, focusing on their moisture sources and the transport of moisture to cyclone centers. For this purpose, 8 d backward trajectories are calculated for all air parcels in the vicinity of cyclone centers with ERA5 reanalysis data, for a subset of the most intense summertime cyclones over the North Atlantic. Subsequently, moisture uptakes along the trajectories of precipitating air parcels are identified using the moisture source diagnostic WaterSip. Using this approach, it is found that the bulk of the precipitation associated with summertime cyclones falls close to the cyclone center beneath the warm conveyor belt (WCB) and along the fronts, mainly during the cyclone's intensification phase. This moisture originates from areas of high ocean evaporation, with significant hotspots on the warm side of the Gulf Stream Front. In addition, some continental sources are found, especially for cyclones in the Labrador Sea. Moisture uptake occurs primarily in regions where the strong sea surface temperature (SST) gradient induces intense ocean evaporation and during cold-air advection within the cyclone's cold sector, where oceanic evaporation is enhanced due to the strong air-sea temperature contrast. The moisture accumulated in the cold sector of the cyclone does not necessarily contribute to precipitation in its own center, but it can act as a source of moisture for a subsequent cyclone. As cyclones mature, distances between the moisture source and the location where the moisture rains out decrease, but the atmospheric residence time of moisture of about 4 d remains approximately the same throughout the cyclone life cycle. This is because the decrease in source distance is compensated by weaker winds and less strong convergence. Overall, these results are fairly similar to those found in a previous study for winter cyclones, although in winter there is more moisture exchange between primary and secondary cyclones, and stronger vertical ascent in the WCB. Summer cyclones, on the other hand, are distinguished by their greater moisture supply from continental sources, and the significant influence from cyclones of tropical origin undergoing extratropical transition.
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 distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 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 tête enseignante, 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 ».