Spatial and Temporal Variabilities of Climate Extremes over Canada in a Changing Climate
Notice bibliographique
Résumé
In the past few decades, there have been more extreme climate events occurring worldwide, constituting a growing risk for our societies. For example, Canada has experienced several extreme precipitation events that resulted in billions of dollars of damage, such as the flood events of Calgary and Toronto in 2013. Meanwhile, the 2001–2002 drought in the Canadian Prairies (CP) swept almost the entire southern part of the country, which was recorded as one of the top ten worst droughts observed over the instrumental period. However, most past studies have focused on changes in the mean climate (such as precipitation and temperature). This dissertation aims to address the spatial and temporal variabilities of climate extremes in Canada under the possible impact of a changing climate, which will improve our understanding of the changing hydroclimate extremes in Canada. Therefore, the objectives of this dissertation are: (1) to characterize spatiotemporal changes of climate extremes under the possible impacts of climate change; (2) to identify how atmospheric convection, temperature, and humidity have contributed to climate extremes; (3) to detect the influences of large-scale climate patterns on climate extremes in Canada. Chapter 2 investigates the spatial and temporal changes in precipitation extremes over Canada, as well as their teleconnections to large-scale climate patterns by using trend analysis, principal component analysis, and wavelet analysis. The results show that extreme precipitation defined from 10 extreme precipitation indices of Canada has generally become more severe since the mid-twentieth century. Meanwhile, strong teleconnections are found between extreme precipitation and climate indices, but the effects of climate patterns differ from region to region. Chapter 3 analyses the relationship between Convective Available Potential Energy (CAPE) and extreme precipitation event, which indicates a positive correlation over much of the eastern US and some parts of the Canadian prairies. In addition, increasing temperature and surface specific humidity could potentially lead to an overall increase in CAPE and extreme precipitation observed over these regions. Chapter 4 studies the variations in drought characteristics in terms of duration, frequency, area, and severity in Canada using the Standardized Precipitation Evapotranspiration Index (SPEI) at seasonal and annual time scales. The results suggest that droughts in Canada have generally become less severe over 1950-2016, and the relationships between climate patterns and drought variability have changed over time. Chapter 5 evaluates the non-stationary behavior of dry and wet spells in Canada using the generalized extreme value (GEV) distribution and Bayesian quantile regression. This analysis shows that dry spells have aggravated in the southern Canadian Prairie from 1979 to 2018, and the stationarity has been compromised as more grids are found to be non-stationary under the impacts of El Niño–Southern Oscillation (ENSO) and Pacific-North American pattern (PNA). Conclusions and future research are provided in Chapter 6.
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 | 0,001 |
| Science ouverte | 0,000 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,004 | 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 ».