Temporal Analysis for the Identification of Extreme Rainfall Events Recorded in Uruguay Over a 30-Year Period (1991–2021)

Uruguay is a country susceptible to extreme events (heavy rainfall or drought) due to the large variation in rainfall. The identification of extreme events at a regional scale is essential since the impact due to climate change could become devastating and extended. Significant changes in climate trends make it difficult to predict extreme events. In this study, the variability of precipitation from 1991 to 2021 was analyzed at five meteorological stations of the National Institute of Agricultural Research (INIA). The data used are publicly available in open sources. The statistical analysis of the accumulated precipitation at each station shows that the stations of Tacuarembó and Salto Grande, located in the country's northern region, have a higher annual accumulated precipitation. Due to the nature of the precipitation records, a classical decomposition was performed to analyze the time series, revealing better results for the additive model and showing the seasonality in the data. This information is used to describe the behavior of the precipitation records with the possibility of making projections of the extreme events identified. The decomposition results revealed the presence of extreme events, such as heavy rainfall and prolonged periods of drought. For heavy rain events, the maximum rainfall values were determined for each station and the return periods were calculated using the Gumbel probability. The Salto Grande station is the station with the highest seasonal precipitation records for spring, summer and fall for a return period of 10 years.