Show simple item record Bryan, A.M. en Bertman, S.B. en Carroll, M.A. en Dusanter, S. en Edwards, G.D. en Forkel, R. en Griffith, S. en Geunther, A.B. en Hansen, R.F. en Helmig, D. en Jobson, B.T. en Keutsch, F.N. en Lefer, B.L. en Pressley, S.N. en Shepson, P.B. en Stevens, P.S. en Steiner, A.L. en 2014-11-12T20:27:58Z en 2014-11-12T20:27:58Z en 2012 en
dc.identifier.citation Bryan, A. M., Bertman, S. B., Carroll, M. A., Dusanter, S., Edwards, G. D., Forkel, R., . . . Steiner, A. L. (2012). In-canopy gas-phase chemistry during CABINEX 2009: Sensitivity of a 1-D canopy model to vertical mixing and isoprene chemistry. Atmospheric Chemistry and Physics, 12(18), 8829-8849. en
dc.description.abstract Vegetation emits large quantities of biogenic volatile organic compounds (BVOC). At remote sites, these compounds are the dominant precursors to ozone and secondary organic aerosol (SOA) production, yet current field studies show that atmospheric models have difficulty in capturing the observed HOx cycle and concentrations of BVOC oxidation products. In this manuscript, we simulate BVOC chemistry within a forest canopy using a one-dimensional canopy-chemistry model (Canopy Atmospheric CHemistry Emission model; CACHE) for a mixed deciduous forest in northern Michigan during the CABINEX 2009 campaign. We find that the base-case model, using fully-parameterized mixing and the simplified biogenic chemistry of the Regional Atmospheric Chemistry Model (RACM), underestimates daytime in-canopy vertical mixing by 50–70% and by an order of magnitude at night, leading to discrepancies in the diurnal evolution of HOx, BVOC, and BVOC oxidation products. Implementing observed micrometeorological data from above and within the canopy substantially improves the diurnal cycle of modeled BVOC, particularly at the end of the day, and also improves the observation-model agreement for some BVOC oxidation products and OH reactivity. We compare the RACM mechanism to a version that includes the Mainz isoprene mechanism (RACM-MIM) to test the model sensitivity to enhanced isoprene degradation. RACM-MIM simulates higher concentrations of both primary BVOC (isoprene and monoterpenes) and oxidation products (HCHO, MACR+MVK) compared with RACM simulations. Additionally, the revised mechanism alters the OH concentrations and increases HO2. These changes generally improve agreement with HOx observations yet overestimate BVOC oxidation products, indicating that this isoprene mechanism does not improve the representation of local chemistry at the site. Overall, the revised mechanism yields smaller changes in BVOC and BVOC oxidation product concentrations and gradients than improving the parameterization of vertical mixing with observations, suggesting that uncertainties in vertical mixing parameterizations are an important component in understanding observed BVOC chemistry. en
dc.language.iso en_US en
dc.publisher Copernicus Publications on behalf of the European Geosciences Union en
dc.relation.isversionof en
dc.rights © 2012 Authors. CC Attribution 3.0 License. en
dc.rights.uri en
dc.subject aerosol en
dc.subject atmospheric chemistry en
dc.subject concentration (composition) en
dc.subject gas phase reaction en
dc.subject isoprene en
dc.subject one-dimensional modeling en
dc.subject oxidation en
dc.subject parameterization en
dc.subject sensitivity analysis en
dc.subject vertical mixing en
dc.title In-canopy gas-phase chemistry during CABINEX 2009: Sensitivity of a 1-D canopy model to vertical mixing and isoprene chemistry en
dc.type Article en
dc.altmetrics.display false en

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