Atmospheric Chemistry and Physics (Jul 2016)
Speciation of OH reactivity above the canopy of an isoprene-dominated forest
- J. Kaiser,
- J. Kaiser,
- K. M. Skog,
- K. Baumann,
- S. B. Bertman,
- S. B. Brown,
- S. B. Brown,
- W. H. Brune,
- J. D. Crounse,
- J. A. de Gouw,
- J. A. de Gouw,
- J. A. de Gouw,
- E. S. Edgerton,
- P. A. Feiner,
- A. H. Goldstein,
- A. H. Goldstein,
- A. Koss,
- A. Koss,
- P. K. Misztal,
- T. B. Nguyen,
- K. F. Olson,
- J. M. St. Clair,
- J. M. St. Clair,
- J. M. St. Clair,
- A. P. Teng,
- S. Toma,
- P. O. Wennberg,
- P. O. Wennberg,
- R. J. Wild,
- R. J. Wild,
- L. Zhang,
- F. N. Keutsch
Affiliations
- J. Kaiser
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- J. Kaiser
- now at: School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- K. M. Skog
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- K. Baumann
- Atmospheric Research & Analysis Inc, Cary, NC, USA
- S. B. Bertman
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
- S. B. Brown
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- S. B. Brown
- Department of Chemistry, University of Colorado, Boulder, CO, USA
- W. H. Brune
- Department of Meteorology, Pennsylvania State University, University Park, PA, USA
- J. D. Crounse
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
- J. A. de Gouw
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- J. A. de Gouw
- Department of Chemistry, University of Colorado, Boulder, CO, USA
- J. A. de Gouw
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, USA
- E. S. Edgerton
- Atmospheric Research & Analysis Inc, Cary, NC, USA
- P. A. Feiner
- Department of Meteorology, Pennsylvania State University, University Park, PA, USA
- A. H. Goldstein
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
- A. H. Goldstein
- Department of Civil and Environmental Engineering, University of California, Berkeley, CA, USA
- A. Koss
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- A. Koss
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, USA
- P. K. Misztal
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
- T. B. Nguyen
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
- K. F. Olson
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
- J. M. St. Clair
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
- J. M. St. Clair
- now at: Joint Center for Earth Systems Technology, University of Maryland Baltimore County, Baltimore, MD, USA
- J. M. St. Clair
- now at: Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
- A. P. Teng
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
- S. Toma
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
- P. O. Wennberg
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
- P. O. Wennberg
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA
- R. J. Wild
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- R. J. Wild
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, USA
- L. Zhang
- Department of Meteorology, Pennsylvania State University, University Park, PA, USA
- F. N. Keutsch
- School of Engineering and Applied Sciences and Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- DOI
- https://doi.org/10.5194/acp-16-9349-2016
- Journal volume & issue
-
Vol. 16
pp. 9349 – 9359
Abstract
Measurements of OH reactivity, the inverse lifetime of the OH radical, can provide a top–down estimate of the total amount of reactive carbon in an air mass. Using a comprehensive measurement suite, we examine the measured and modeled OH reactivity above an isoprene-dominated forest in the southeast United States during the 2013 Southern Oxidant and Aerosol Study (SOAS) field campaign. Measured and modeled species account for the vast majority of average daytime reactivity (80–95 %) and a smaller portion of nighttime and early morning reactivity (68–80 %). The largest contribution to total reactivity consistently comes from primary biogenic emissions, with isoprene contributing ∼ 60 % in the afternoon, and ∼ 30–40 % at night and monoterpenes contributing ∼ 15–25 % at night. By comparing total reactivity to the reactivity stemming from isoprene alone, we find that ∼ 20 % of the discrepancy is temporally related to isoprene reactivity, and an additional constant ∼ 1 s−1 offset accounts for the remaining portion. The model typically overestimates measured OVOC concentrations, indicating that unmeasured oxidation products are unlikely to influence measured OH reactivity. Instead, we suggest that unmeasured primary emissions may influence the OH reactivity at this site.
