Multidecadal Variability in Atmospheric Dust Preserved in an Ice Core From the Southern Slopes of the Himalayas

Abstract

Ice cores from the Himalayan region, downwind from vast arid and densely populated areas, are important in revealing long-term dust variability and the driving factors behind such variability. However, logistical challenges in reaching the region have hindered the retrieval of long-term dust records from the southern side of the Himalayas. This study presents a 145-year record of atmospheric dust from an 81.2-m ice core drilled in the Trambau (TB) glacier, a south-facing glacier in the Nepal Himalaya, covering 1875–2019 CE. Comparison of dust records from the northern and southern slopes of the Himalayas indicates that the ice core from the southern slopes has preserved higher dust concentrations and larger particle sizes than records from the northern slopes. Furthermore, the TB core record shows 50- to 70-year multidecadal variability, positively correlated with the Atlantic Multidecadal Oscillation (AMO). Based on correlation and composite analyses using ERA5 reanalysis data, AMO phases have been linked with surface wetness/dryness in dust source regions in the Middle East and Southwest Asia, likely contributing to variations in dust loading at the TB core site.