1] Department of Ecological Sciences, Universidad de Chile, Las Palmeras 3425, Casilla 653, Santiago, Chile [2] Institute of Ecology and Biodiversity, Universidad de Chile, Las Palmeras 3425, Casilla 653, Santiago, Chile [3] Center for Climate Research and Resilience, Universidad de Chile, Blanco Encalada 2002, Santiago 8370449, Chile [4].
1] CONICET-Museo Argentino de Ciencias Naturales Bernardino Rivadavia, Sección Palinología del Cuaternario, Av. Angel Gallardo 470, Buenos Aires C1405DJR, Argentina [2].
Nat Commun. 2014 Jul 10;5:4375. doi: 10.1038/ncomms5375.
Late twentieth-century instrumental records reveal a persistent southward shift of the Southern Westerly Winds during austral summer and autumn associated with a positive trend of the Southern Annular Mode (SAM) and contemporaneous with glacial recession, steady increases in atmospheric temperatures and CO2 concentrations at a global scale. However, despite the clear importance of the SAM in the modern/future climate, very little is known regarding its behaviour during pre-Industrial times. Here we present a stratigraphic record from Lago Cipreses (51°S), southwestern Patagonia, that reveals recurrent ~200-year long dry/warm phases over the last three millennia, which we interpret as positive SAM-like states. These correspond in timing with the Industrial revolution, the Mediaeval Climate Anomaly, the Roman and Late Bronze Age Warm Periods and alternate with cold/wet multi-centennial phases in European palaeoclimate records. We conclude that SAM-like changes at centennial timescales in southwestern Patagonia represent in-phase interhemispheric coupling of palaeoclimate over the last 3,000 years through atmospheric teleconnections.
二十世纪后期的仪器记录显示，在南半球夏季和秋季，与南极环状模（SAM）的正趋势相关联，南风持续向南移动，同时伴随着冰川退缩、全球大气温度和 CO2 浓度的稳定上升。然而，尽管 SAM 在现代/未来气候中具有明显的重要性，但对于其在工业化前时期的行为却知之甚少。在这里，我们展示了来自拉戈·西普雷塞斯（51°S）的沉积记录，该记录显示了过去三千年中反复出现的约 200 年长的干旱/温暖阶段，我们将其解释为类似于 SAM 的正状态。这些阶段与工业革命、中世纪气候异常、罗马和青铜时代晚期暖期相对应，与欧洲古气候记录中的寒冷/湿润的多百年期阶段交替出现。我们的结论是，在过去 3000 年中，西南巴塔哥尼亚以百年为时间尺度的类似于 SAM 的变化代表了通过大气遥相关，半球间古气候的同相耦合。
