Southward shift of the westerly jet intensified late Holocene dust storms on the Tibetan Plateau

Abstract

The climate change on the Tibetan Plateau (TP) exhibits a north-south dipole trend during the Holocene. However, it is unclear whether regional differences exist in the variations and driving mechanisms of dust storm activities across the entire TP, and whether these mechanisms align with those found in monsoonal northern China. Here, we present a high-resolution Holocene record of dust storms from an undisturbed lake in the research gap area of the TP, and compile previously published records from other TP regions. Our findings indicate that the dust storm activity increased from the early Holocene to the late Holocene, peaking after 5 cal ka BP. Importantly, our comparison with other dust storm records reveals a unified intensification of dust storm activity across the entire TP during the late Holocene, a pattern distinctly different from the north-south dipole trend of precipitation variation. Moreover, this unified pattern of dust storm intensification across the TP cannot be explained by the decreasing intensity of the East Asian winter monsoon (EAWM) during the Holocene. The observations suggested a limited role for precipitation and EAWM in modulating TP dust storms on the millennial timescale during this period. By contrast, the increases in dust storms on the TP after 5 cal ka BP correlates well to the southward shift of the westerly jet driven by the North Atlantic Oscillation (NAO). As the NAO transitioned to a negative phase during the late Holocene, a meandering westerly jet shifted southward to the interior of the TP, intensifying wind intensity and leading to dust storm outbreaks.