Multi-decadal to centennial hydro-climate variability and linkage to solar forcing in the Western Mediterranean during the last 1000 years

• Published in: Scientific Reports
• Main Authors: BRAHIM, Yassine Ait, WASSENBURG, Jasper, CRUZ, Francisco, SIFEDDINE, Abdel, SCHOLZ, Denis, BOUCHAOU, Lhoussaine, DASSIE, Emilie, JOCHUM, Klaus, EDWARDS, R. Lawrence, CHENG, Hai
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2018
• Subjects: Palaeoclimate; Planète et Univers [physics]/Sciences de la Terre/Climatologie; North Atlantic; North Atlantic oscillation
• Online Access: https://oskar-bordeaux.fr/handle/20.500.12278/188761; https://hdl.handle.net/20.500.12278/188761; https://doi.org/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, δ18O 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 δ18O 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.