Atmospheric Forcing of Dust Source Activation across East Asia

Abstract. East Asian dust storms impact the health and livelihoods of millions but the atmospheric processes responsible are far from fully understood because suitable observations are lacking. Here we analyse dust source activation (DSA) frequency data for East Asia (80–130° E, 27–52° N, January 2016 through December 2023, Chen et al., 2025, https://doi.org/10.1088/1748-9326/addee6) to understand atmospheric controls on dust activation. We show that East Asia's two primary dust source regions (Chen et al., 2025) display distinct diurnal and seasonal variations in DSA frequency. A southern region, sandwiched between the Mongolian Plateau and the Tibetan Plateau, chiefly consisting of the Taklimakan Desert and the Alashan Plateau, is active year-round, with 40–60 % of events predominantly occurring during late morning (09:00–12:00 local solar time; LST) under clear-sky conditions. We show that breakdown of the Low-level Jet (LLJ) is a major control on dust activation across this region (not only the Taklimakan Desert), driven by morning heating of the land surface, deepening the convective boundary layer and momentum transfer to the land surface. A northern region, centred on the Mongolian Plateau-Gobi Desert is dust-active from morning to afternoon (08:00–14:00 LST), primarily under cloudy conditions, driven by the passage of low-pressure systems. A third (less active) dust source region, the Tibetan Plateau, is typically active during winter afternoons in response to strong mountain-valley winds. Meso- and local-scale winds are more extensive drivers of dust activation across East Asia than previously documented, adding uncertainty to model predictions of future dust emissions in East Asia under a warming climate.