Temporal variability of aridity in Argentina during the period 1961–2020

Abstract

This paper examines the temporal variability of aridity in Argentina during the period 1961–2020. Monthly datafrom the Climatic Research Unit (CRU) were used to define climate types according to the Aridity Index (AI) fromthe United Nations Environment Programme (UNEP). Argentina presents a variety of climates ranging from aridand semiarid to subhumid and humid, suggesting simultaneous water deficit and excess conditions. However, anaridity increase in the past six decades has been observed in much of the country, contrasting with reduced areasthat have become wetter. Since these changes were not uniform across the study area, a regional-level analysiswas conducted to adequately capture the aridity temporal patterns, including trends, jumps, seasonality, andcycles. In general, there was a decrease in the annual AI in most regions, with non-linear patterns such as longterm oscillations, shorter-duration cycles, and abrupt variations in the average. Seasonal aridity changes showedvariabilities according to the season, with higher humidity during summer and autumn, and greater aridityduring winter and spring. Simultaneously, seasonal AI experienced periodic behavior with significant arid andhumid cycles alternating every 10–15 years. These findings highlight the complexity of climate changes, whichvary by region and season.