Identification of the frequency of extreme precipitation events in southeastern South America

MARTINEZ DAIANA MICAELA; SOLMAN, SILVINA A.

Conferencia; International Conference on Regional Climate ICRC-CORDEX 2023; 2023

Southeastern South America (SESA), delimited between 38°S–25°S and 64°W–51°W, ischaracterized as one of the regions in the world with the highest frequency of occurrence ofintense storms associated with deep convection, mainly during the spring and summermonths (Zipser et al., 2006). These convective storm systems induce extreme precipitationevents and produce most of the rain in the warm season (Rasmussen and Houze, 2016),causing significant damage (floods, intense winds, hail) resulting in a high impact oneconomic and social activities. Considering that the occurrence of extreme precipitationevents in SESA is associated with specific synoptic patterns (SP), the objective of this workwas to detect the frequency of extreme precipitation events from the occurrence of certain SP,in spring (October to December, OND) and summer (January to March, JFM) in two regionalclimate models (RCMs) Daily data from the CORDEX-CORE models available in the South American domain(REMO 2015 and RegCM 4.7 driven by three GCMs) in the period 1979-2005 was used. To detect the frequency of occurrence of extreme precipitation events in the RCMs, ananalogue method was applied based on SP precursors of extreme events. This methodology made it possible to determine the mechanisms that lead to situationsassociated with the occurrence of a higher or lower number of extreme precipitation events.In addition, it is an input that could be used in future work to assess changes in the frequencyof extreme events for future climate change scenarios.