Analysis of heat-related phenomena and their interactions at different spatio-temporal scales

Possega, Marco (2023) Analysis of heat-related phenomena and their interactions at different spatio-temporal scales, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Il futuro della terra, cambiamenti climatici e sfide sociali, 35 Ciclo.
Documenti full-text disponibili:
[img] Documento PDF (English) - Accesso riservato fino a 1 Giugno 2024 - Richiede un lettore di PDF come Xpdf o Adobe Acrobat Reader
Disponibile con Licenza: Creative Commons Attribution Non-commercial No Derivatives 4.0 (CC BY-NC-ND 4.0) .
Download (31MB) | Contatta l'autore


This thesis analyzes the impact of heat extremes in urban and rural environments, considering processes related to severely high temperatures and unusual dryness. The first part deals with the influence of large-scale heatwave events on the local-scale urban heat island (UHI) effect. The temperatures recorded over a 20-year summer period by meteorological stations in 37 European cities are examined to evaluate the variations of UHI during heatwaves with respect to non-heatwave days. A statistical analysis reveals a negligible impact of large-scale extreme temperatures on the local daytime urban climate, while a notable exacerbation of UHI effect at night. A comparison with the UrbClim model outputs confirms the UHI strengthening during heatwave episodes, with an intensity independent of the climate zone. The investigation of the relationship between large-scale temperature anomalies and UHI highlights a smooth and continuous dependence, but with a strong variability. The lack of a threshold behavior in this relationship suggests that large-scale temperature variability can affect the local-scale UHI even in different conditions than during extreme events. The second part examines the transition from meteorological to agricultural drought, being the first stage of the drought propagation process. A multi-year reanalysis dataset involving numerous drought events over the Iberian Peninsula is considered. The behavior of different non-parametric standardized drought indices in drought detection is evaluated. A statistical approach based on run theory is employed, analyzing the main characteristics of drought propagation. The propagation from meteorological to agricultural drought events is found to develop in about 1-2 months. The duration of agricultural drought appears shorter than that of meteorological drought, but the onset is delayed. The propagation probability increases with the severity of the originating meteorological drought. A new combined agricultural drought index is developed to be a useful tool for balancing the characteristics of other adopted indices.

Tipologia del documento
Tesi di dottorato
Possega, Marco
Dottorato di ricerca
Settore disciplinare
Settore concorsuale
Parole chiave
heatwave, urban heat island, urban climate, European cities, drought propagation, agricultural drought, meteorological drought, Iberian Peninsula, non-parametric drought index
Data di discussione
21 Giugno 2023

Altri metadati

Gestione del documento: Visualizza la tesi