In Situ Measurement of Dust Particle Transport to the Tropopause Layer over the Northern Tibetan Plateau

Previous satellite observations and simulations have shown that dust particles can be transported to the upper troposphere, but there is very little evidence from in situ observations. This study provides the first balloon–borne measurements of dust particle transport to the tropopause layer during a dust event over the northern Tibetan Plateau (TP). Vertical profiles of size–resolved aerosol number distributions were obtained before and during the dust event, which revealed that the number of dust particles larger than 0.416 μm increased significantly throughout the troposphere and above the tropopause at the sounding site. The backward trajectories of these enhanced dust particles suggest that the particles at different altitudes exhibit different transport pathways and dust emission sources. In the lower troposphere, the dust particles originated from the Taklamakan Desert following flow to the northern TP. The particles above the tropopause originated from the Thar Desert (TD). They experienced both synoptic–scale lifting associated with the trough and jet stream over the TD and forced uplift due to the high terrain of the TP.