A 2000 Year Saharan Dust Event Proxy Record from an Ice Core in the European Alps

摘要

Dust events originating from the Saharan desert have far-reaching environmental impacts, but the causal mechanism of magnitude and occurrence of Saharan dust events (SDEs) during the preinstrumental era requires further research, particularly as a potential analog for future climate. Using an ultrahigh resolution glacio-chemical record from the 2013 Colle Gnifetti ice core drilled in the Swiss-Italian Alps, we reconstructed a 2000-year-long summer Saharan dust record. We analyzed both modern (1780-2006) and premodern Common Era (CE) major and trace element records to determine air mass source regions to the Colle Gnifetti glacier and assess similarities to modern and reconstructed climate trends in the Northern Hemisphere. This new proxy SDE reconstruction, produced using measurements from a novel, continuous ultrahigh-resolution (120-μm) ice core analysis method (laser ablation-inductively coupled plasma-mass spectrometer) is comprised of 316,000 data points per element covering the period 1-1820 CE. We found that the Colle Gnifetti ice core captures an anomalous increase in Saharan dust transport during the onset of the Medieval Climate Anomaly (870-1000 CE) and records other prominent shorter events (CE, 140-170, 370-450, 1320-1370, and 1910-2000), offering a framework for new insights into the implications of Saharan dust variability.