State-of-the-art climate models project droughts of stronger intensity and longer persistence in many arid and semi-arid regions such as northern Patagonia, which constitutes a serious concern worldwide. Moisture availability has a significant influence on the dynamic, stability and function of terrestrial ecosystems. In this study, we used wood samples from 260 Austrocedrus chilensis trees growing in northwestern Patagonia to reconstruct the Standardized Precipitation Evapotranspiration Index (SPEI) for the last millennium (1055–2014). Our reconstruction explained 41.6% of the variance contained in the November–December SPEI at a 1-month scale for the period 1930–2013. The SPEI reconstruction has provided a long record of extreme pluvial (1060s, 1090s, 1200s, 1300s, 1360 s2, 1390s, 1400s, 1550s, 1580s, 1580s, 1630s, 1940s, 1960s, and 2000s) and drought events (1070s, 1150s, 1170s, 1180s, 1270s, 1310s, 1430s, 1450s, 1570s, 1600s, 1620s, and 1950s) for northwest Argentine Patagonia. Although the SPEI reconstruction indicates that the frequency of extreme events has increased since 1950, our record indicates that current levels have not exceeded those previously reached, particularly when compared to those recorded around the suggested periods for the Medieval Warm and towards the end of the Little Ice Age. The spatial and temporal relationships associated with the South Annular Mode and the Pacific Sea Surface Temperature variability as expressed by the Tripole Index indicated that the temporal variability observed in the SPEI reconstruction is modulated by hemispheric-scale atmospheric circulation dynamics. These climate forcings are likely responsible for the intensity and the rate of occurrence of extreme weather events in northwestern Patagonia. Furthermore, the SPEI reconstruction showed a spatial and temporal pattern similar to that observed in previous PDSI-based reconstructions. This study provides robust evidence of hydroclimatic variations for extratropical sectors of South America, improving our knowledge of the climate dynamics during the last millennium and allowing us to review the recently observed increase in wet and dry events in a long-term historical context.

最新的气候模型预测，在许多干旱和半干旱地区（例如巴塔哥尼亚北部），干旱强度和持续时间更长，这引起了全世界的严重关注。水分供应对陆地生态系统的动态，稳定性和功能有重大影响。在这项研究中，我们使用了来自260个澳大利亚南方辣椒的木材样品在巴塔哥尼亚西北部生长的树木重建最近一个千年（1055年至2014年）的标准降水蒸散指数（SPEI）。我们的重建工作以19个月至1930年期间的1个月规模解释了SPEI 11月至12月SPEI中包含的41.6％的差异。SPEI重建提供了极端暴雨（1060s，1090s，1200s，1300s，1360 s2、1390s，1400s，1550s，1580s，1580s，1630s，1940s，1960s和2000s）和干旱事件（1070s，1150s，阿根廷西北巴塔哥尼亚的1170、1180、1270、1310、1430、1450、1570、1600、1620和1950年代）。尽管SPEI的重建表明自1950年以来极端事件的发生频率有所增加，但我们的记录表明，目前的水平并未超过先前达到的水平，特别是与建议在中世纪暖期和小冰期末期记录的记录进行比较时。由Tripole指数表示的与南环形模式和太平洋海表温度变化性相关的时空关系表明，在SPEI重建过程中观察到的时间变化性是由半球尺度的大气环流动力学调节的。这些气候强迫可能是西北巴塔哥尼亚地区极端天气事件的强度和发生率的原因。此外，SPEI重建显示出与以前基于PDSI的重建相似的时空格局。这项研究提供了南美温带地区水气候变化的有力证据，