A51N-0266
Impact of Stronger Production and Loss Rates of Secondary Organic Aerosols on their Global Distribution and Budget
Friday, 18 December 2015
Poster Hall (Moscone South)
Alma Hodzic1, Prasad S Kasibhatla2, Christopher D Cappa3, Sasha Madronich4, Duseong S. Jo5, Rokjin Park5 and Jose L Jimenez6, (1)University Corporation for Atmospheric Research, Boulder, CO, United States, (2)Duke University, Durham, NC, United States, (3)University of California Davis, Civil and Environmental Engineering, Davis, CA, United States, (4)National Center for Atmospheric Research, Boulder, CO, United States, (5)Seoul National University, Earth and Environmental Sciences, Seoul, South Korea, (6)University of Colorado at Boulder, Dept. of Chemistry and Biochemistry, Boulder, CO, United States
Abstract:
Organic aerosols are observed to be the major constituents of submicron particles worldwide, and yet their atmospheric lifecycle including formation, ageing, and removal processes is poorly understood. Recent laboratory and ambient measurements suggest that both production yields and removal rates of chemically produced secondary organic aerosols (SOA) are much stronger and more diverse than currently assumed in chemistry-climate models (which typically consider wet deposition as the major loss process). In this study, we re-assess the global SOA distribution and budget with newly proposed SOA production and loss processes derived from these recent measurements, as well as from theoretical calculations. We evaluate and discuss the relative importance of removal pathways for organic vapors and particles (e.g. dry and wet deposition, photo-dissociation, evaporation, and heterogeneous surface reactions), and their effect on the SOA vertical distribution and budget using the GEOS-Chem global chemistry-transport model. We compare simulated SOA from various model configurations against ground, aircraft and satellite measurements to assess the extent to which these new developments in our understanding of SOA formation and removal processes are consistent with observed characteristics of the SOA distribution. Our results show strong changes in predicted vertical profiles of organic aerosols with higher SOA concentrations in the boundary layer and lower concentrations in the upper troposphere, which appear to be in a better agreement with aircraft measurements.
