Viazzo et al. (2026) Characterizing individual and compound wind and precipitation extremes over southeastern South America: spatial variability, seasonality and weather types

Identification

• Journal: Weather and Climate Extremes
• Year: 2026
• Date: 2026-08-05
• Authors: Carla Viazzo, María Laura Bettolli
• DOI: 10.1016/j.wace.2026.100940

Research Groups

• Departamento de Ciencias de la Atmósfera y los Océanos, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (DCAO-FCEN-UBA)
• Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)

Short Summary

This study characterizes compound wind and precipitation extremes over southeastern South America, assessing spatial and seasonal variability, seasonality, and weather types. The results show that CWPEs are frequent in eastern SESA, with more than 40% of PEs being CWPEs.

Objective

• Characterize the spatial and seasonal variability of individual and compound wind and precipitation extreme occurrences at the daily timescale.
• Discuss observational uncertainty.
• Analyze synoptic environments associated with widespread CWPE days and related spatial distribution of WE, PE, and CWPE occurrences using a weather-typing approach.

Study Configuration

• Spatial Scale: Southeastern South America (SESA), covering Uruguay, northeastern and central Argentina, southern portions of Brazil and Paraguay.
• Temporal Scale: Daily timescale, with analysis conducted over the 1981–2019 period.

Methodology and Data

• Models used: ERA5, ERA5-Land, MSWX, WFDE5, NASA POWER datasets.
• Data sources: Gridded observational datasets, including reanalysis products (ERA5, ERA5-Land), high-resolution gridded near-surface dataset (MSWX), bias-corrected hourly near-surface variables (WFDE5), and meteorological variables derived from MERRA-2 (NASA POWER).

Main Results

• CWPEs are frequent in eastern SESA, with more than 40% of PEs being CWPEs.
• Seasonality of individual extremes varies across SESA: PEs occur mostly during summer in northern and western parts, while eastern SESA exhibits a more even distribution throughout the four seasons.
• WE occurrences exhibit less spatial variability, with ∼45% occurring in spring and ∼20%–45% in winter.

Contributions

• This study provides the first comprehensive assessment of CWPEs over SESA, addressing knowledge gaps in understanding large-scale processes favoring compound wind and precipitation extremes.
• The results enhance our understanding of the spatial and seasonal variability of individual and compound extreme occurrences at the daily timescale.

Funding

• Not specified in the provided text.

Citation

@article{Viazzo2026Characterizing,
  author = {Viazzo, Carla and Bettolli, María Laura},
  title = {Characterizing individual and compound wind and precipitation extremes over southeastern South America: spatial variability, seasonality and weather types},
  journal = {Weather and Climate Extremes},
  year = {2026},
  doi = {10.1016/j.wace.2026.100940},
  url = {https://doi.org/10.1016/j.wace.2026.100940}
}