Upper troposphere aerosol formation enhanced by monsoon lofted pollution

Year: 2026

Authors: Williamson CJ., Borrmann S., Brauner P., Brock CA., Campos T., Christoudias T., D’Amato F., Dragoneas A., Eppers O., Honomichl S., Kohl M., Ktzllner F., Kupc A., Lee YR., Lyu M., Michailoudi G., Pan LL., Perring AE., Pozzer A., Simone D., Smith WP., Tost H., Ueyama R., Ullmann K., Vakkari V., Viciani S., Virkkula A., Weigel R., Woods S., Xenofontos C.

Autors Affiliation: Finnish Meteorol Inst, Helsinki, Finland; Univ Helsinki, Inst Atmospher & Earth Syst Res Phys, Helsinki, Finland; Max Planck Inst Chem, Mainz, Germany; NOAA, Chem Sci Lab, Boulder, CO USA; NSF Natl Ctr Atmospher Res, Atmospher Chem Observat & Modeling Lab, Boulder, CO USA; Cyprus Inst, Climate & Atmosphere Res Ctr, Nicosia, Cyprus; CNR, Natl Inst Opt CNR INO, Sesto Fiorentino, Italy; Johannes Gutenberg Univ Mainz, Inst Atmospher Phys, Mainz, Germany; Univ Vienna, Fac Phys, Aerosol Phys & Environm Phys, Vienna, Austria; Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA USA; Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO USA; Colgate Univ, Dept Chem, Hamilton, NY USA; NASA, Earth Sci Div, Ames Res Ctr, Moffett Field, CA 94035 USA; North West Univ, Chem Resource Beneficiat, Atmospher Chem Res Grp, Potchefstroom, South Africa.

Abstract: The Asian Summer Monsoon (ASM) lofts air from polluted boundary layer regions to the upper-troposphere and lower-stratosphere. High concentrations of aerosols have been observed in ASM outflow, which influence climate by interacting with radiation and clouds and affecting atmospheric composition. Prior observations indicate that small particles form in ASM convective outflow. Laboratory and modelling studies hypothesise the importance of lofted ammonia in this process and growth of the particles to sizes where they can interact with radiation and clouds. Here we combine in-situ observation in ASM convective outflow with trajectory and Earth-system modelling to show the likely role of pollution in enhancing ASM outflow new particle formation. We show that the particles grow to sizes where they can interact with clouds and radiation, and are transported over large areas within the troposphere and stratosphere.

Journal/Review: NATURE COMMUNICATIONS

Volume: 17 (1)      Pages from: 9672-1  to: 9672-17

More Information: C.W. and D.S disclose support for the research of this work from the NSF Award No. AGS 1853932. C.W. also discloses support from the Research Council of Finland Award No. 359166, ACCAERO, and the Finnish Ministry of Education and Culture and CSC – IT Centre for Science (Decision diary number OKM/10/524/2022). T.C. And K.U. disclose support by the NSF National Centre for Atmospheric Research, Atmospheric Chemistry Observations and Modelling Laboratory. The NSF NCAR GV is managed and operated by the NSF NCAR Earth Observing Laboratory. NSF NCAR is sponsored by the U.S. National Science Foundation under Cooperative Agreement No. 1852977. RU disclose supported for the research of this work from NASA Upper Atmosphere Composition Observations Programme. O.E., F.K., S.B., H.T. and R.W. disclose support for the research of this work from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – TRR 301 – Project-ID 763 428312742: The tropopause region in a changing atmosphere. G.M. discloses support from NOAA Earth’s Radiation Budget programme, the NASA Upper Atmospheric Composition Programme and NSF. A.V. discloses support from the Research Council of Finland project BBrCAC, decision nr. 341271. The COLD2 deployment was funded by the UE 7th FP StratoClim Project, grant agreement no. 603557. T.C., A.P., and C.X. disclose funding for the research of this work from the E uropean Union (EU)’s Horizon 2020 research and innovation programme under grant agreement no. 856612 (EMME-CARE); EU Marie Sk & lstrok;odowska-Curie Actions Doctoral Network CLOUD-DOC 101073026; Horizon Europe project FOCI (no. 101056783). W.P:S discloses support for the research of this work from the t NSF AGS-1853929 and NASA Grant 80NSSC24K0706. A.K. discloses support from the Austrian Science Fund FWF’s Erwin Schrodinger Fellowship J-3613.
KeyWords: Asian Summer Monsoon; Cloud Condensation Nuclei; Tropical Tropopause Layer; Particle Formation Npf; In-situ Observation; Remote Troposphere; Size Distributions; Mass-spectrometry; Source Regions; Anticyclone
DOI: 10.1038/s41467-026-75073-x