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Universidad de Buenos Aires (2022)

Olas de calor estivales en el centro-este de Argentina : de la física a los impactos

Coronato, Tanea

Titre : Olas de calor estivales en el centro-este de Argentina : de la física a los impactos

Summer heatwaves in central-eastern Argentina : from physics to impact studies

Auteur :  : Coronato, Tanea

Université de soutenance : Universidad de Buenos Aires

Grade : Doctor de la Universidad de Buenos Aires en el área de Ciencias de la Atmósfera y los Océanos 2022

Résumé partiel
This thesis addresses the issue of heat waves affecting central-eastern Argentina from different points of view and scales. Aspects related to the physical processes that catalyze or modulate the occurrence of heat waves, their characteristics, statistics and change projections are studied, and decreasing in scale, impact studies are carried out. The thesis goes beyond the typical comparison of modeled versus observed climatologies, as it includes the analysis of a series of ad-hoc experiments for the study of the processes at the soil-atmosphere interface and a novel characterization of heat waves. Moreover, an innovative and interdisciplinary approach to assess the impact of climate and its variability on the cooling energy demand of social housing is presented. Previous studies have shown that central-eastern Argentina is a climatic transition zone with land-atmosphere coupling. This thesis explores the effect of this coupling (i.e., of the feedback between soil moisture and the atmosphere) on the warm extremes of the temperature field. The analysis of a series of numerical experiments designed ad-hoc for the study of land-atmosphere interactions shows that such interactions affect the tail of the probability distribution of the thermal field, impacting on the warm extremes and on their persistence. Furthermore, the existence of both land-atmosphere coupling and relatively dry soil conditions enhance the occurrence of temperature extremes. In absence of land-atmosphere coupling, the impact of soil moisture conditions (dry or wet) is weaker. These results suggest that the role of interactions between soil moisture and the atmosphere is more important than the impact of stationary soil moisture anomalies. Climate change projections for central-eastern Argentina show increases in the persistence of hot days, warm nights and humid days. These impact on heat waves change projections, which were analyzed and categorized. From a multivariate analysis that includes information on both temperature and moisture content, three main types of heat waves emerge : hot and dry (“dry”), extremely hot and humid (“intense”) and humid with particularly hot nights (“humid”). All of these events are projected to become more extreme in the future. In addition, a higher frequency of occurrence of “intense” events is expected as a consequence of the projected changes for the mean fields : higher temperatures, but with stronger increases in minimum temperatures and in wet bulb temperatures rather than in maximum temperatures. Moreover, heat waves that are considered extreme and unlikely under current climate conditions are typical events in the future climate, and this feature accentuates towards the end of the century and under scenarios of higher greenhouse gas emissions.

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Page publiée le 25 mars 2023