CaltechAUTHORS
Published February 16, 2018 | Version Published + Supplemental Material
Journal Article Open

Decadal changes in summertime reactive oxidized nitrogen and surface ozone over the Southeast United States

Creators

  • 1. ROR icon Nanjing University of Information Science and Technology
  • 2. ROR icon University of Alaska Fairbanks
  • 3. ROR icon Lamont-Doherty Earth Observatory
  • 4. ROR icon University of California, Berkeley
  • 5. ROR icon California Institute of Technology
  • 6. ROR icon University of Washington
  • 7. ROR icon Earth System Research Laboratory
  • 8. ROR icon Cooperative Institute for Research in Environmental Sciences
  • 9. ROR icon Colorado State University
  • 10. ROR icon Aerodyne Research
  • 11. ROR icon Langley Research Center
  • 12. ROR icon University of Maryland, Baltimore County
  • 13. ROR icon Goddard Space Flight Center
  • 14. ROR icon Institute of Arctic and Alpine Research
  • 15. ROR icon Ames Research Center
  • 16. ROR icon University of New Hampshire
  • 17. ROR icon Princeton University
  • 18. ROR icon Geophysical Fluid Dynamics Laboratory

Abstract

Widespread efforts to abate ozone (O_3) smog have significantly reduced emissions of nitrogen oxides (NO_x) over the past 2 decades in the Southeast US, a place heavily influenced by both anthropogenic and biogenic emissions. How reactive nitrogen speciation responds to the reduction in NO_x emissions in this region remains to be elucidated. Here we exploit aircraft measurements from ICARTT (July–August 2004), SENEX (June–July 2013), and SEAC4RS (August–September 2013) and long-term ground measurement networks alongside a global chemistry–climate model to examine decadal changes in summertime reactive oxidized nitrogen (RON) and ozone over the Southeast US. We show that our model can reproduce the mean vertical profiles of major RON species and the total (NO_y) in both 2004 and 2013. Among the major RON species, nitric acid (HNO_3) is dominant (∼ 42–45 %), followed by NO_x (31 %), total peroxy nitrates (ΣPNs; 14 %), and total alkyl nitrates (ΣANs; 9–12 %) on a regional scale. We find that most RON species, including NO_x, ΣPNs, and HNO_3, decline proportionally with decreasing NO_x emissions in this region, leading to a similar decline in NO_y. This linear response might be in part due to the nearly constant summertime supply of biogenic VOC emissions in this region. Our model captures the observed relative change in RON and surface ozone from 2004 to 2013. Model sensitivity tests indicate that further reductions of NO_x emissions will lead to a continued decline in surface ozone and less frequent high-ozone events.

Additional Information

© Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License. Received: 29 Jun 2017 – Discussion started: 13 Jul 2017. Revised: 23 Dec 2017 – Accepted: 03 Jan 2018 – Published: 16 Feb 2018. The authors thank Vaishali Naik (NOAA GFDL) for providing emission inventories in the GFDL AM3 model and Leo Donner (NOAA GFDL) and William Cooke (UCAR/NOAA) for help with the convection scheme of AM3. Jingyi Li, Jingqiu Mao, and Larry W. Horowitz acknowledge support from the NOAA Climate Program Office under grant no. NA13OAR431007. Jingqiu Mao, Larry W. Horowitz, and Arlene M. Fiore acknowledge support from the NOAA Climate Program Office under grant no. NA14OAR4310133. John D. Crounse and Paul O. Wennberg acknowledge support from NASA grants (NNX12AC06G and NNX14AP46G). Jingyi Li acknowledges support from the Startup Foundation for Introducing Talent of NUIST grant no. 2243141701014 and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD). Data availability. Observational datasets and modeling results are available upon request to the corresponding author (jmao2@alaska.edu). The authors declare that they have no conflict of interest. Edited by: Nga Lee Ng Reviewed by: three anonymous referees

Attached Files

Published - acp-18-2341-2018.pdf

Supplemental Material - acp-18-2341-2018-supplement.pdf

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Additional details

Identifiers

Eprint ID
85183
Resolver ID
CaltechAUTHORS:20180307-130604960

Funding

National Oceanic and Atmospheric Administration (NOAA)
NA13OAR431007
National Oceanic and Atmospheric Administration (NOAA)
NA14OAR4310133
NASA
NNX12AC06G
NASA
NNX14AP46G
Nanjing University of Information Science and Technology
2243141701014
Priority Academic Program Development of Jiangsu Higher Education Institutions

Dates

Created
2018-03-07
Created from EPrint's datestamp field
Updated
2021-11-15
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Division of Geological and Planetary Sciences (GPS)