Estimates of Regional Source Contributions to the Asian Tropopause Aerosol Layer Using a Chemical Transport Model Journal of Geophysical Research: Atmospheres

The Asian Tropopause Aerosol Layer (ATAL) represents an accumulation of aerosol in the upper troposphere and lower stratosphere associated with the Asian Summer Monsoon. Here we simulate the ATAL for summer 2013 with the GEOS ‐Chem chemical transport model and explore the likely composition of ATAL aerosols and the relative contributions of regional anthropogenic sources versus those from farther a field. The model indicates signi ficant contributions from organic aerosol, nitrate, sulfate, and ammonium aerosol, with regional anthropogenic precursor sources dominant. The model underestimatesaerosol backscatter in the ATAL during summer 2013, compared with Cloud ‐Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite instrument. Tests of a more physically based