Ozarks Isoprene Experiment (OZIE): Measurements and modeling of the “isoprene volcano”

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Read Full Article (file size: 1244632 bytes) Cited by JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 110, D18307, doi:10.1029/2005JD005800, 2005 Ozarks Isoprene Experiment (OZIE): Measurements and modeling of the “isoprene volcano” Christine Wiedinmyer Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, Colorado, USA Jim Greenberg Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, Colorado, USA Alex Guenther Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, Colorado, USA Brian Hopkins Department of Civil and Environmental Engineering, Washington State University, Pullman, Washington, USA Kirk Baker Lake Michigan Air Directors Consortium, Des Plaines, Illinois, USA Chris Geron U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA Paul I. Palmer Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA Bryan P. Long Department of Chemical Engineering, Washington University, St. Louis, Missouri, USA Jay R. Turner Department of Chemical Engineering, Washington University, St. Louis, Missouri, USA Gabrielle Pétron Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, Colorado, USA Peter Harley Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, Colorado, USA Thomas E. Pierce U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA Atmospheric Sciences Modeling Division, National Oceanic and Atmospheric Administration, Research Triangle Park, North Carolina, USA Brian Lamb Department of Civil and Environmental Engineering, Washington State University, Pullman, Washington, USA Hal Westberg Department of Civil and Environmental Engineering, Washington State University, Pullman, Washington, USA William Baugh Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, Colorado, USA Mike Koerber Lake Michigan Air Directors Consortium, Des Plaines, Illinois, USA Mark Janssen Lake Michigan Air Directors Consortium, Des Plaines, Illinois, USA Abstract The Ozarks Isoprene Experiment (OZIE) was conducted in July 1998 in Missouri, Illinois, Indiana, and Oklahoma. OZIE was designed to investigate the presumed strong isoprene emission rates from the Missouri Ozarks, where there is a high density of oak trees that are efficient isoprene emitters. Ground, balloon, and aircraft measurements were taken over a three-week study period; 0-D and 3-D chemical models were subsequently used to better understand the observed isoprene emissions from the Ozarks and to investigate their potential regional-scale impacts. Leaf-level measurements for two oak tree species yielded normalized average isoprene emission capacities of 66 mgC g⁻¹ h⁻¹, in good agreement with values used in current biogenic emissions models. However, the emission capacities exhibited a temperature dependence that is not captured by commonly used biogenic emission models. Isoprene mixing ratios measured aloft from tethered balloon systems were used to estimate isoprene fluxes. These measurement-derived fluxes agreed with BEIS3 estimates within the relatively large uncertainties in the estimates. Ground-level isoprene mixing ratios exhibited substantial spatial heterogeneity, ranging from <1 to 35 ppbv. The agreement between measured isoprene mixing ratios and regional-scale chemical transport model estimates was improved upon averaging the ground-level isoprene data observed at several sites within a representative area. Ground-level formaldehyde (HCHO) mixing ratios were very high (up to 20 ppbv) and were consistently higher than mixing ratios predicted by a regional chemical transport model. The spatial distribution and magnitude of the elevated HCHO concentrations showed good agreement with GOME satellite column observations of HCHO. Received 25 January 2005; accepted 20 July 2005; published 24 September 2005. Keywords: isoprene; formaldehyde; regional air quality; biogenic emissions; ozone; Ozarks. Index Terms: 0365 Atmospheric Composition and Structure: Troposphere: composition and chemistry; 0345 Atmospheric Composition and Structure: Pollution: urban and regional (0305, 0478, 4251); 0368 Atmospheric Composition and Structure: Troposphere: constituent transport and chemistry; 0315 Atmospheric Composition and Structure: Biosphere/atmosphere interactions (0426, 1610). Read Full Article (file size: 1244632 bytes) Cited by Citation: Wiedinmyer, C., et al. (2005), Ozarks Isoprene Experiment (OZIE): Measurements and modeling of the “isoprene volcano”, J. Geophys. Res., 110, D18307, doi:10.1029/2005JD005800. Copyright 2005 by the American Geophysical Union.

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