Regional interplay between natural climate variability and anthropogenic climate change in Central Argentina

Abstract

Understanding the interplay between natural climate variability and anthropogenic climate change is crucial for effective adaptation strategies. However, such studies remain limited for many regions. This study examines climate variability and long-term trends in Central Argentina region, focusing on regional patterns, their links to large-scale circulation anomalies, and the influence of large-scale modes of variability. Minimum temperature (Tmn), maximum temperature (Tmx), and precipitation (Prcp) anomalies were analyzed using in-situ observations and reanalysis data (CRU, ERA5) from 1931 to 2020. Results show significant warming trends in Tmn, particularly in spring and summer, while Tmx trends vary seasonally and locally, showing a partial negative correlation with Prcp. A trend toward wetter summers and drier winters suggests an intensification of the region´s monsoonal-like seasonal cycle. Empirical Orthogonal Function and Singular Spectrum Analyses identified the leading regional variability patterns for each variable. Non-linear trends are observed, positive for Tmn and Tmx, and negative for Prcp, correlating with global warming and the Atlantic Multidecadal Oscillation. Tmn trends also link to the Southern Annular Mode. An irregular ~ 3-year cycle is also discernible for Tmn and Tmx, with Tmn showing a significant El Niño-Southern Oscillation connection. Prcp and Tmx exhibit a ~ 9-year cycle with no significant link with an oceanic forcing. To date, interannual variability has reduced the influence of long-term trends on regional climate anomalies, but this interplay may shift in the future with greater global warming levels. Understanding this interaction is essential for assessing regional climate hazards and refining adaptation strategies.