Evaluating the Isoprene Oxidation Mechanism Using Aircraft Observations from SENEX 2013
Margaret Rosemary Marvin1, Glenn M Wolfe2,3, Ross J Salawitch4, Timothy P Canty5, Jennifer Kaiser6, Thomas F Hanisco7, Frank N Keutsch8, Martin Graus9,10, Carsten Warneke9,11, Joost A de Gouw12,13, Jessica Gilman9,10, Brian M Lerner9,10, Courtney Dyan Hatch14, Ilana B Pollack15,16, Jeff Peischl10,17, Thomas B Ryerson18, Patrick R Veres9,10, Dr. James Roberts, PhD19, Kyung-Eun Min9,10, Steven S Brown20, John S Holloway9,10, Kenneth C. Aikin11,21, Ben H Lee22, Felipe Lopez-Hilfiker23 and Joel A Thornton24, (1)University of Maryland College Park, College Park, MD, United States, (2)UMBC/NASA Goddard, Greenbelt, MD, United States, (3)University of Maryland Baltimore County, Baltimore, MD, United States, (4)University of Maryland College Park, Department of Chemistry and Biochemistry, College Park, MD, United States, (5)University of Maryland, College Park, Department of Atmospheric and Oceanic Science, College Park, United States, (6)Georgia Institute of Technology, School of Civil and Environmental Engineering, Atlanta, GA, United States, (7)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (8)University of Wisconsin Madison, Madison, WI, United States, (9)Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States, (10)NOAA Earth System Research Lab, Boulder, CO, United States, (11)NOAA Earth System Research Laboratory, Chemical Sciences Division, Boulder, CO, United States, (12)University of Colorado Boulder, Department of Chemistry, Boulder, United States, (13)University of Colorado Boulder - CIRES, Boulder, United States, (14)Hendrix College, Chemistry, Conway, AR, United States, (15)NOAA ESRL Chemical Sciences Division, Boulder, CO, United States, (16)University of Colorado at Boulder, Cooperative Institute for Research in Environmental Sciences - CIRES, Boulder, CO, United States, (17)Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado Boulder, Boulder, United States, (18)NOAA Earth System Research Lab, Chemical Sciences Division, Boulder, CO, United States, (19)NOAA ESRL, Chemical Sciences Laboratory, Boulder, CO, United States, (20)NOAA, Earth System Research Laboratory, Boulder, CO, United States, (21)Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, United States, (22)University of Washington Seattle Campus, Seattle, WA, United States, (23)Tofwerk, Thun, Switzerland, (24)University of Washington Seattle Campus, Department of Atmospheric Sciences, Seattle, United States
Abstract:
The chemical mechanism for isoprene oxidation is associated with a great deal of uncertainty. As a result, implementation of the isoprene oxidation mechanism by regional models may lead to misrepresentation of ozone, organic aerosol, and related species important to air quality. Formaldehyde (HCHO) is a major product of isoprene oxidation and thus provides observational constraint on the mechanism. The SouthEast NEXus (SENEX) 2013 aircraft campaign provides observations of HCHO over the Southeast United States, an environment that is high in isoprene but variable in NOx, with the lowest concentrations of NOx in remote regions such as the Ozarks and the highest near cities and power plants. Such a range of conditions provides a unique opportunity to map out the sensitivity of HCHO to changes in the isoprene oxidation mechanism. We use the University of Washington Chemical Model (UWCMv2.2) to evaluate the HCHO dependence on isoprene and NOx throughout the range of conditions observed during SENEX. Particular emphasis will be placed on the effects of newly proposed mechanisms, including enhanced OH regeneration and updated alkyl nitrate chemistry.
