Caracterização das ondas de calor na Antártica: variabilidade espacial e sazonal

• Ano de defesa: 2026
• Autor(a) principal: Barcelos, Márcia Eduarda Aldrighi
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Santa Maria; Brasil; UFSM; Programa de Pós-Graduação em Meteorologia; Centro de Ciências Naturais e Exatas
• Palavras-chave em Português: Variabilidade sazonal; Extremos de temperatura; Climatologia; Reanálise climática; Seasonal variability; Temperature extremes; Climatology; Climate reanalysis; CNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::METEOROLOGIA
• Link de acesso: http://repositorio.ufsm.br/handle/1/38588

Heatwaves have become one of the main indicators of recent climate change, including in polar regions. In Antarctica, episodes of extreme warming have been recorded with increasing frequency over recent decades, highlighting the need for systematic analyses of their spatial and seasonal variability. In this context, this study aims to characterize heatwaves in Antarctica based on maximum air temperature, investigating their frequency, persistence, and intensity throughout the seasons of the year. Daily maximum temperature data from the ERA5 reanalysis were used for the period from 1980 to 2024. The analyses were conducted on a seasonal basis, considering austral summer (DJF), autumn (MAM), winter (JJA), and spring (SON). Thermal extremes were identified using the 90th percentile of daily maximum temperature, calculated for each grid point and season, allowing the adoption of relative thresholds adjusted to local climatology. Days with temperatures exceeding this threshold were classified as heat extremes, without imposing a minimum duration criterion.To identify climatically homogeneous regions, a cluster analysis based on the seasonal climatology of the 90th percentile of maximum temperature was applied. From these regions, persistence, frequency, and intensity metrics of extreme events were evaluated. The results indicate strong seasonal modulation and pronounced spatial heterogeneity, with higher occurrence and persistence of extremes during summer and late spring, particularly over the Antarctic Peninsula and coastal areas. Event intensity shows marked differences between seasons and regions, indicating that thermal severity is not solely associated with event frequency or duration.These findings highlight the importance of integrated approaches for characterizing heatwaves in Antarctica and provide a basis for future studies on trends and impacts of thermal extremes under a warming climate.