[A-AS04] Extreme Events and Mesoscale Weather: Observations and Modeling

[AAS04-P08] Southeastern Brazil: Unraveling the Link Between Intense Precipitation and Low-Pressure Systems

*Hikari Viviane Yamamoto Fukuda¹, Tomoki Miyakawa¹ (1.AORI, The University of Tokyo)

Keywords:Heavy precipitation, Coast, Brazil, Natural disater, Low-pressure zone, Climate change

In Brazil, precipitation is a phenomenon that can severely affect society, potentially causing severe disasters such as flooding, specially due to the geomorphological characteristics of the area (Bou et al., 2015), and landslides (da Fonseca Aguiar and Cataldi, 2021). Intense precipitation events in the austral summer (December, January and February) are responsible for practically all cases of natural disasters in the southeast region (Lima et al., 2010), comprising the states of São Paulo, Rio de Janeiro, Espírito Santo and Minas Gerais. Previously, different studies have presented relationships between precipitation and the South Atlantic Convergence Zone (da Fonseca Aguiar and Cataldi, 2021; Figueroa et al., 1995; Ambrizzi and Ferraz, 2015), also known as SACZ, and case studies of subtropical cyclones (Reboita et al., 2018; Dutra et al., 2017). In the present study, throughout the austral summer, it was observed that intense precipitation in southeastern Brazil frequently occurs in an environment with a low-pressure region located close to the southeastern coast of Brazil. Thus, instead of relating precipitation to the SACZ or subtropical cyclones, the study intends to focus on how the low-pressure region originates and what is the relationship with intense precipitation in southeastern Brazil. In recent decades, total annual precipitation and consecutive wet days seem to have increased (Carvalho and Wanderley, 2022). Pezzi et al. (2023) observed that in the years 2021/2022, the wet season in South America was considered abnormal, causing an excess of precipitation in relation to the historical climatology, about 300 mm of positive precipitation anomaly. We will discuss how climate change may affect the low-pressure zone and subsequently the intense precipitation events in the southeast region.

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