Variability of extreme precipitation events in the Northeastern Argentine region

Abstract

The Northeastern Argentine (NEA) region is one of the most productive and vulnerable to climate risk due to frequent extreme precipitation events (EPE). The present study aims to identify and explain the spatiotemporal distribution of precipitation in the NEA region to assess its heterogeneity. A cluster analysis from Ward’s hierarchical method was applied using observational precipitation collected at meteorological stations during 1959–2018. The elbow method and a nonhierarchical analysis of K-means were also useful to define the correct number of clusters. The three groups obtained responded to an east-west precipitation gradient that generated a zonal atmospheric circulation, and the positive anomalies mostly coincided with El Niño-Southern Oscillation (ENSO) events. Although they had similar seasonal rainfall and annual amplitudes, each subregion presented its specific variability at different temporal scales. Positive anomalies were more significant in the east of the NEA region, which is reflected in the displacement of isohyets in the last decades. Our results suggest that almost the entire NEA region is highly vulnerable to EPE, but with higher intensity and frequency in the center and east. Due to the agricultural and ecological importance of this region and the socioeconomic effects of EPE, studies with more detailed scales than the regional ones are necessary.