The Siberian High drove increasing dust storm activity on the Tibetan Plateau on the centennial scale during the past 2000 years

Abstract

Precipitation records from the Tibetan Plateau (TP) for the past ∼2000 years show a north–south dipole pattern. Precipitation is one of the main factors affecting dust storms in this region, but it is unclear whether regional differences exist in dust storm activity and its driving mechanisms across the entire TP, and whether these mechanisms were consistent on the Holocene millennial scale and the centennial scale during the past 2000 years. To address this uncertainty, we reconstructed a high-resolution record of dust storm activity for the past ∼2000 years from an undisturbed lake site on the southwestern TP, in an area which is poorly investigated. We found that dust storm activity gradually increased over the past 2000 years and peaked during the Little Ice Age (LIA). Comparison with other dust storm records revealed a consistent trend of dust storm intensification across the entire TP, which contradicts the previously proposed north–south dipole pattern of precipitation variation. To explain this, we propose that dust storm outbreaks across the entire TP during the LIA were driven by the spatial coupling between TP dust source areas and cold fronts resulting from an enhanced Siberian High (SH). Compared with the driving mechanism of the millennial-scale variations of the westerly jet during the Holocene, there was a clear shift to SH intensity as the principal driving mechanism of TP dust storms on the centennial timescale. Overall, our findings demonstrate different degrees of importance of these two hemispheric-scale circulations for dust storm activity across the entire TP, on different time scales, forming a scientific foundation for dust storm management on a global scale.