Ait Brahim Yassine, Wassenburg Jasper A, Cruz Francisco W, Sifeddine Abdelfettah, Scholz Denis, Bouchaou Lhoussaine, Dassié Emilie P, Jochum Klaus P, Edwards R Lawrence, Cheng Hai
Insistute for Global Environmental Change, Xi'an Jiaotong University, Xi'an, China.
Climate Geochemistry Department, Max Planck Institute for Chemistry, Mainz, Germany.
Sci Rep. 2018 Nov 28;8(1):17446. doi: 10.1038/s41598-018-35498-x.
Here we present a new composite record from two well-dated speleothem records from two caves in Northern Morocco. The high-resolution record covers the last millennium allowing to detect multi-decadal to centennial periodicities. Over the industrial period, δO values of our speleothems are shown to be dominated by the main mode of decadal variability in the North Atlantic region: the North Atlantic Oscillation (NAO). Statistical analyses confirm the previously reported multi-decadal variability related to the influence of the Atlantic Multidecadal Oscillation (AMO) in the region. High power and persistent centennial-scale periodicities, similar to the Vries-Suess 200-year solar cycle, are observed as well. Indeed, comparison between solar activity reconstructions and our record confirms the in-phase relationship on centennial time-scales. Low δO values, and hence negative phases of NAO that bring precipitation towards the Western Mediterranean, are observed during well-known solar minima periods. The results are consistent with previous models which describe low irradiance as a trigger for southward shifts of precipitation-bearing westerlies during winter.
在此，我们展示了来自摩洛哥北部两个洞穴中两个年代测定准确的洞穴石笋记录的新综合记录。高分辨率记录涵盖了过去一千年，能够检测到数十年至百年尺度的周期性变化。在工业时期，我们洞穴石笋的δO值显示主要受北大西洋地区年代际变化的主要模式——北大西洋涛动（NAO）的主导。统计分析证实了先前报道的与该地区大西洋多年代际振荡（AMO）影响相关的数十年变化。还观测到了与弗里斯 - 苏斯200年太阳周期相似的高功率且持续的百年尺度周期性变化。事实上，太阳活动重建与我们的记录之间的比较证实了百年时间尺度上的同相位关系。在著名的太阳极小期期间，观测到低δO值，从而出现将降水带向地中海西部的NAO负相位。这些结果与先前的模型一致，这些模型将低辐照度描述为冬季期间携带降水的西风带向南移动的触发因素。
