Trends in convective parameters in southern Brazil: a preliminary analysis

Authors

DOI:

https://doi.org/10.5902/2179460X84048

Keywords:

Convective parameters, Southern Brazil, Trends, Adaptation to climate change

Abstract

This study is a preliminary investigation, for southern Brazil, about possible changes in the last four decades in the magnitude of two convective parameters indicative of atmospheric environments favorable to severe convective storms. The parameters selected for this research, the convective available potential energy (CAPE), and the magnitude of the vector wind difference between the surface and 6 km above ground level (DLS), are, respectively, indicative of the presence of conditional instability and vertical wind shear in a deep layer. These parameters were computed for hourly tropospheric profiles (or pseudo-soundings) extracted from the native vertical grid of the ERA5 reanalysis for the period between 1980 and 2021 for the grid points nearest to the three state capitals of southern Brazil: Curitiba, Florianópolis and Porto Alegre. The analysis, for each location, of the trend in the time series of CAPE and DLS, averaged for every single month, was carried out with the aid of the non-parametric Mann-Kendall test. The results obtained from the tropospheric profiles of the ERA5 reanalysis reveal a negative trend in the extreme values of CAPE, especially for Porto Alegre, but accompanied by an increase in the magnitude of DLS for all locations. Therefore, in this preliminary analysis, the implications from CAPE and DLS for the conditioning of environments favorable to severe storms display opposite signs for the selected locations. Additional research addressing the frequency of environments conducive to severe storms is needed for a more complete assessment of the impact of these trends.

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Author Biographies

Letícia de Oliveira dos Santos, Universidade Federal de Santa Maria

Master's in Meteorology at Universidade Federal de Santa Maria (2016), PhD Candidate in the Graduate Program in Meteorology at the Universidade Federal de Santa Maria, main research topic focuses on the climatology of severe convective storms. 

Ernani de Lima Nascimento, Universidade Federal de Santa Maria

Associate Professor III (Class D, Level 3) in the Undergraduate and Graduate Programs in Meteorology at the Universidade Federal de Santa Maria (UFSM). PhD in Meteorology from the University of Oklahoma (USA) (2002);  Main research topics include: (i) convective dynamics; (ii) local convective storms, downdrafts, and tornadoes; (iii) mesoscale meteorological observation systems; (iv) subtropical synoptic systems; (v) local atmospheric circulations.

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Published

2025-04-30

How to Cite

Santos, L. de O. dos, & Nascimento, E. de L. (2025). Trends in convective parameters in southern Brazil: a preliminary analysis. Ciência E Natura, 47(esp. 3), e84048. https://doi.org/10.5902/2179460X84048

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