An Inversion Framework for Optimizing Non‐Methane VOC Emissions Using Remote Sensing and Airborne Observations in Northeast Asia During the KORUS‐AQ Field Campaign

Journal of Geophysical Research Atmospheres, vol. 127, pp. e2021JD035844

Abstract

Abstract We aim to reduce uncertainties in CH2O and other volatile organic carbon (VOC) emissions through assimilation of remote sensing data. We first update a three‐dimensional (3D) chemical transport model, GEOS‐Chem with the KORUSv5 anthropogenic emission inventory and inclusion of chemistry for aromatics and C2H4, leading to modest improvements in simulation of CH2O (normalized mean bias (NMB): −0.57 to −0.51) and O3 (NMB: −0.25 to −0.19) compared against DC‐8 aircraft measurements during KORUS‐AQ; the mixing ratio of most VOC species are still underestimated. We next constrain VOC emissions using CH2O observations from two satellites (OMI and OMPS) and the DC‐8 aircraft during KORUS‐AQ. To utilize data from multiple platforms in a consistent manner, we develop a two‐step Hybrid Iterative Finite Difference Mass Balance and four‐dimensional variational inversion system (Hybrid IFDMB‐4DVar). The total VOC emissions throughout the domain increase by 47%. The a posteriori simulation reduces the low biases of simulated CH2O (NMB: −0.51 to −0.15), O3 (NMB: −0.19 to −0.06), and VOCs. Alterations to the VOC speciation from the 4D‐Var inversion include increases of biogenic isoprene emissions in Korea and anthropogenic emissions in Eastern China. We find that the IFDMB method alone is adequate for reducing the low biases of VOCs in general; however, 4D‐Var provides additional refinement of high‐resolution emissions and their speciation. Defining reasonable emission errors and choosing optimal regularization parameters are crucial parts of the inversion system. Our new hybrid inversion framework can be applied for future air quality campaigns, maximizing the value of integrating measurements from current and upcoming geostationary satellite instruments.

Authors 13

1. Jinkyul Choi corresponding

   University of Colorado Boulder

   Affiliation as printed

   Environmental Engineering Program University of Colorado Boulder CO USA

   Environmental Engineering Program, University of Colorado, Boulder, CO, USA

2. Daven K. Henze

   University of Colorado Boulder

   Affiliation as printed

   Department of Mechanical Engineering University of Colorado Boulder CO USA

   Department of Mechanical Engineering, University of Colorado, Boulder, CO, USA

3. Hansen Cao

   University of Colorado Boulder

   Affiliation as printed

   Department of Mechanical Engineering University of Colorado Boulder CO USA

   Department of Mechanical Engineering, University of Colorado, Boulder, CO, USA

4. Caroline R. Nowlan

   Smithsonian Astrophysical Observatory · Center for Astrophysics Harvard & Smithsonian

   Affiliation as printed

   Harvard‐Smithsonian Center for Astrophysics Cambridge MA USA

   Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA

5. Gonzalo González Abad

   Smithsonian Astrophysical Observatory · Center for Astrophysics Harvard & Smithsonian

   Affiliation as printed

   Harvard‐Smithsonian Center for Astrophysics Cambridge MA USA

   Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA

6. Hyeong‐Ahn Kwon

   Smithsonian Astrophysical Observatory · Center for Astrophysics Harvard & Smithsonian

   Affiliation as printed

   Harvard‐Smithsonian Center for Astrophysics Cambridge MA USA

   Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA

7. Hyung‐Min Lee

   Ewha Womans University

   Affiliation as printed

   Department of Environmental Science and Engineering Ewha Womans University Seoul South Korea

   Department of Environmental Science and Engineering, Ewha Womans University, Seoul, South Korea

8. Yujin J. Oak

   Seoul National University

   Affiliation as printed

   School of Earth and Environmental Sciences Seoul National University Seoul South Korea

   School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea

9. Rokjin J. Park

   Seoul National University

   Affiliation as printed

   School of Earth and Environmental Sciences Seoul National University Seoul South Korea

   School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea

10. Kelvin H. Bates

    Harvard University

    Affiliation as printed

    School of Engineering and Applied Sciences Harvard University Cambridge MA USA

    School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA

11. Joannes D. Maasakkers Aachen SRON Netherlands Institute for Space Research Utrecht The Netherlands SRON Netherlands Institute for Space Research

    Space Research Organisation Netherlands

    Affiliation as printed

    SRON Netherlands Institute for Space Research Utrecht The Netherlands

    SRON Netherlands Institute for Space Research, Utrecht, The Netherlands

12. Armin Wisthaler

    University of Oslo · Universität Innsbruck

    Affiliation as printed

    Department of Chemistry University of Oslo Oslo Norway

    Institute for Ion Physics and Applied Physics University of Innsbruck Innsbruck Austria

    Department of Chemistry, University of Oslo, Oslo, Norway

    Institute for Ion Physics and Applied Physics, University of Innsbruck, Innsbruck, Austria

13. Andrew J. Weinheimer

    NSF National Center for Atmospheric Research · NSF NCAR Atmospheric Chemistry Observations & Modeling

    Affiliation as printed

    Atmospheric Chemistry Observations and Modeling Laboratory National Center for Atmospheric Research Boulder CO USA

    Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA