A13E-0388
Sources and Fate of Reactive Carbon in an Isoprene-Dominated Forest
Monday, 14 December 2015
Poster Hall (Moscone South)
Jennifer Kaiser1, Kate Skog2, Karsten Baumann3, Steven B Bertman4, Steven S Brown5, William H Brune6, John Crounse7, Joost A De Gouw5, Eric S Edgerton8, Philip Allen Feiner6, Allen H Goldstein9, Abigail Koss10, Pawel K Misztal9, Tran Nguyen11, Kevin Frederick Olson9, Jason St. Clair12, Alex Teng11, Paul O Wennberg13, Robert J Wild14, Li Zhang15 and Frank N Keutsch16, (1)University of Wisconsin- Madison, Madison, WI, United States, (2)UW-Madison, Madison, WI, United States, (3)Atmospheric Research and Analysis, Morrisville, NC, United States, (4)Western Michigan University, Kalamazoo, MI, United States, (5)NOAA Boulder, Boulder, CO, United States, (6)Pennsylvania State University Main Campus, University Park, PA, United States, (7)California Institute of Technology, Division of Geological and Planetary Sciences, Pasadena, CA, United States, (8)Atmospheric Research & Analysis, Inc., Cary, NC, United States, (9)University of California Berkeley, Berkeley, CA, United States, (10)University of Colorado at Boulder, Boulder, CO, United States, (11)California Institute of Technology, Pasadena, CA, United States, (12)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (13)California Institute of Technology, Division of Engineering and Applied Science, Pasadena, CA, United States, (14)Colorado University/NOAA/ESRL, Boulder, CO, United States, (15)Pennsylvania State Univ, University Park, PA, United States, (16)Harvard University, Cambridge, MA, United States
Abstract:
On a global scale, biogenically emitted isoprene is the most abundant nonmethane volatile organic compound (VOC), and therefore a key source of reactive carbon in the earth’s atmosphere. Because there are significant uncertainties in the oxidation mechanism of isoprene, and little work examining the deposition rates of the key oxidation products, predicting the total amount, the speciation, and the fate of isoprene oxidation products is difficult. Therefore, the fate of reactive carbon is also poorly constrained.
During the 2013 Southern Oxidant and Aerosol Study (SOAS) field campaign, OH reactivity, isoprene, and key first-generation and later-generation isoprene oxidation products were measured over the South-East United States. The observed OH reactivity can largely be accounted for, with an average “missing” reactivity of ~25%. OH reactivity was largely dominated by isoprene, with only small contributions from isoprene-derived oxidation products. In contrast, not all oxidation products show good agreement, despite well parameterized dry deposition and dilution rates. Using the viewpoint of OH reactivity, we discuss the sources of reactive carbon at this site. Then, from the viewpoint of oxidized VOCs, we discuss its fate. Measurement and model discrepancies are used to explore the plausibility of unknown physical and chemical carbon sinks.
