Dust records from three ice cores: relationships to spring atmospheric circulation over the Northern Hemisphere

Abstract

Non-sea-salt Mg2+ (nssMg2+) records from three Northern Hemisphere ice cores (Mt. Everest, Himalayas; Mt. Logan, Yukon Territory; and 20D, southern Greenland) are presented as a proxy of atmospheric dust. NssMg2+ concentrations of both Mt. Everest and 20D ice core have increased since the 20th century. Relationships between the three ice core annual nssMg2+ series and instrumental sea-level pressure (SLP) series of spring (March–April–May) are investigated for the last century (AD 1899–1996), in order to develop an understanding of dust aerosol transport over the Northern Hemisphere during the spring season. On a hemispheric scale, an enhanced spring Arctic High weakens dust aerosol transport from central Asia to subarctic regions (e.g., southern Greenland and Yukon Territory), but strengthens transport of dust to the Himalaya (e.g., Mt. Everest). An intensification of the Siberian High may strengthen transport of dust aerosols to Greenland, and an enhancement of the Tibetan High strengthens transport to Himalaya and Yukon regions in spring. A stronger spring Azores High favors dust transport to both the Himalayas and south Greenland. On a regional scale, a deepened spring Icelandic Low and Aleutian Low increases transport of dust aerosols to Greenland and the Yukon Territory, respectively. Understanding these transport patterns is significant for the interpretation of ice core records and reconstruction of atmospheric circulation using longer records.