Climate change in North Patagonian Andes: Recent temperature and precipitation trends

This study examines climate change in the North Patagonian Andes (NPA), analyzing temperature and precipitation trends over the last three decades. Using data from 12 key meteorological stations, we assessed changes in mean annual temperatures and precipitation patterns, with a focus on lee-side precipitation suppression across two 100 km West-East transects: the La Angostura (40.75° S) and Manso (41.5° S) transects. Results reveal a consistent warming trend across all stations, most pronounced at Alerce station in the NPA, where temperatures increased by 0.82 °C per decade since 1993. This warming intensified after 2007, marked by rising temperature anomalies and more frequent hot extremes. Precipitation trends show significant declines in both transects, as reflected in the standardized precipitation index, with moderate to severe droughts becoming increasingly common since 2016. Precipitation trends revealed a notable decline since 2007, especially in the Manso transect, which was more affected by the westward retraction of precipitation isohyets in the last 5 years (2016-2021). These patterns are likely associated with the positive phase of the Southern Annular Mode (SAM), which has driven poleward shifts in storm tracks, reducing NPA precipitation. The observed climate changes have critical implications for regional hydrology and ecosystem dynamics, highlighting the need to monitor interactions between atmospheric circulation (e.g., SAM) and local climate variability. Our findings underscore the urgency of understanding these processes to anticipate impacts of ongoing climate change in the NPA.