Aerosol perturbation in the UTLS region over the Tibetan Plateau

The Asian tropopause aerosol layer (ATAL) was thicker than other regions at the same latitude due to the strong confinement effect of the Asian summer monsoon anticyclone. The size distribution of the particles remains unknown and requires further investigation. Aerosol profiles were measured by balloon-borne sensors (Cobald, POPS) launched from Lhasa (29.66 °N, 91.14 °E), Golmud (36.48 °N, 94.93 °E), and Kunming (25.01 °N, 102.65 °E) China, from 2019 to 2022 over the Tibetan Plateau at the part of the SWOP (Sounding Water vapor, Ozone, and Particle) campaign. The measurements combined with backward trajectories show that the volcano Raikoke (48°N, 153°E) in June 2019 and the dust storm in March 2021 over the Taklamakan desert have significantly impacted on the aerosol layer in the upper troposphere and lower stratosphere (UTLS). The backscatter ratio at wavelength 455 nm of the volcanic plume and dust storm was higher than the ATAL. The particle number density in the volcanic plume is 30 cm^-3, higher than the ATAL and dust storm (10 cm^-3) in the lower stratosphere, with particle diameters centered around 0.42-3.4 μm. In contrast, the dust storm has a high density of up to 100 cm^-3 in the upper troposphere with particle diameters less than 0.42 μm.