A036-0013
Models underestimate the increase of acidity with remoteness biasing radiative impact calculations
Tuesday, 8 December 2020
Poster
Benjamin Nault1,2, Pedro Campuzano-Jost3, Doug A Day3, Duseong Jo4, Jason Clay Schroder5, Hannah M Allen6, Roya Bahreini7, Huisheng Bian8, Donald Ray Blake9, Mian Chin10, Simon L Clegg11, Peter Richard Colarco12, John D Crounse13, Michael Cubison1, Peter DeCarlo14, Jack E Dibb15, Glenn S Diskin16, Alma Hodzic17, Weiwei Hu18, Joseph M Katich19, Michelle J Kim13, Jack Kodros20, Agnieszka Kupc21, Felipe Lopez-Hilfiker22, Eloise Ann Marais23, Ann Middlebrook24, J A Neuman25, John B Nowak26, Brett Palm27, Fabien Paulot28, Jeffrey R Pierce29, Gregory P Schill30, Eric M Scheuer31, Joel A Thornton32, Kostas Tsigaridis33, Paul O Wennberg13, Christina Williamson34 and Jose L Jimenez3, (1)Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States, (2)University of Colorado at Boulder, Department of Chemistry, Boulder, CO, United States, (3)University of Colorado at Boulder, Cooperative Institute for Research in Environmental Sciences (CIRES) and Department of Chemistry, Boulder, CO, United States, (4)University of Colorado at Boulder, Chemistry/CIRES, Boulder, CO, United States, (5)Colorado Department of Public Health and Environment, Denver, CO, United States, (6)California Institute of Technology, Pasadena, CA, United States, (7)University of California Riverside, Environmental Sciences, Riverside, CA, United States, (8)NASA Goddard Space Flight Ctr, Greenbelt, MD, United States, (9)University of California Irvine, Irvine, CA, United States, (10)NASA Goddard SFC, Greenbelt, MD, United States, (11)University of East Anglia, Norwich, United Kingdom, (12)NASA GSFC, Greenbelt, MD, United States, (13)California Institute of Technology, Division of Geological and Planetary Sciences, Pasadena, CA, United States, (14)Johns Hopkins University, Department of Environmental Health and Engineering, Balitmore, MD, United States, (15)University of New Hampshire, Institute for the Study of Earth, Oceans, and Space, Durham, NH, United States, (16)NASA Langley Research Ctr, Hampton, VA, United States, (17)National Center for Atmospheric Research, Boulder, CO, United States, (18)Chinese Academy of Sciences, Guangzhou, China, (19)University of Colorado Cooperative Institute for Research in Environmental Sciences (CIRES) at the NOAA Chemical Sciences Laboratory (CSL), Boulder, CO, United States, (20)Colorado State University, Atmospheric Science, Fort Collins, CO, United States, (21)University of Vienna, Faculty of Physics, Vienna, Austria, (22)University of Washington Seattle Campus, Seattle, WA, United States, (23)University of Leicester, Department of Physics and Astronomy, Leicester, United Kingdom, (24)NOAA Boulder, Boulder, CO, United States, (25)Cooperative Institute for Research in Environmental Sciences (CIRES), NOAA ESRL, Chemical Sciences Laboratory, Boulder, CO, United States, (26)NASA Langley Research Center, Hampton, VA, United States, (27)University of Washington Seattle Campus, Atmospheric Sciences, Seattle, United States, (28)NOAA Geophysical Fluid Dynamics Laboratory, Princeton, NJ, United States, (29)Colorado State University, Department of Atmospheric Science, Fort Collins, CO, United States, (30)NOAA/CIRES, Boulder, CO, United States, (31)University of New Hampshire, Institute for the Study of Earth, Ocean, and Space, Durham, NH, United States, (32)University of Washington, Department of Atmospheric Sciences, Seattle, WA, United States, (33)Columbia University, New York, NY, United States, (34)NOAA/CIRES, Boulder, United States
Abstract:
The inorganic fraction of fine atmospheric aerosol affects numerous physical and chemical processes. However, due to limited global measurements, there is large uncertainty in its burden, composition, and lifetime. Here, extensive airborne observations are used to investigate how two measures of aerosol acidity, the fraction of anions neutralized by ammonium (ammonium balance), and aerosol pH, change from polluted to remote regions. Both parameters strongly decrease with remoteness (distance from source) at all altitudes. Chemical transport models tend to show more neutralized aerosols and higher pH than observed. We show that part of the discrepancy is due to a frequent high bias in ammonia emissions or lifetime, and/or the incorrect assumption of internally mixed sea-salt. The observations suggest very different aerosol properties and impacts, including higher water content and a smaller direct radiative effect. These results indicate the need for better constraints on the emissions and lifetime of inorganic aerosol precursors, especially ammonia.
