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Can a “state of the art” chemistry transport model simulate Amazonian tropospheric chemistry?

Barkley, Michael P. and Palmer, Paul I. and Ganzeveld, Laurens and Arneth, Almut and Hagberg, Daniel and Karl, Thomas and Guenther, Alex and Paulot, Fabien and Wennberg, Paul O. and Mao, Jingqiu and Kurosu, Thomas P. and Chance, Kelly and Müller, J.-F and De Smedt, Isabelle and Van Roozendael, Michel and Chen, Dan and Wang, Yuxuan and Yantosca, Robert M. (2011) Can a “state of the art” chemistry transport model simulate Amazonian tropospheric chemistry? Journal of Geophysical Research D, 116 . Art. No. D16302. ISSN 0148-0227.

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We present an evaluation of a nested high-resolution Goddard Earth Observing System (GEOS)-Chem chemistry transport model simulation of tropospheric chemistry over tropical South America. The model has been constrained with two isoprene emission inventories: (1) the canopy-scale Model of Emissions of Gases and Aerosols from Nature (MEGAN) and (2) a leaf-scale algorithm coupled to the Lund-Potsdam-Jena General Ecosystem Simulator (LPJ-GUESS) dynamic vegetation model, and the model has been run using two different chemical mechanisms that contain alternative treatments of isoprene photo-oxidation. Large differences of up to 100 Tg C yr^(−1) exist between the isoprene emissions predicted by each inventory, with MEGAN emissions generally higher. Based on our simulations we estimate that tropical South America (30–85°W, 14°N–25°S) contributes about 15–35% of total global isoprene emissions. We have quantified the model sensitivity to changes in isoprene emissions, chemistry, boundary layer mixing, and soil NO_x emissions using ground-based and airborne observations. We find GEOS-Chem has difficulty reproducing several observed chemical species; typically hydroxyl concentrations are underestimated, whilst mixing ratios of isoprene and its oxidation products are overestimated. The magnitude of model formaldehyde (HCHO) columns are most sensitive to the choice of chemical mechanism and isoprene emission inventory. We find GEOS-Chem exhibits a significant positive bias (10–100%) when compared with HCHO columns from the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) and Ozone Monitoring Instrument (OMI) for the study year 2006. Simulations that use the more detailed chemical mechanism and/or lowest isoprene emissions provide the best agreement to the satellite data, since they result in lower-HCHO columns.

Item Type:Article
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URLURL TypeDescription DOIArticle
Paulot, Fabien0000-0001-7534-4922
Wennberg, Paul O.0000-0002-6126-3854
Additional Information:© 2011 by the American Geophysical Union. Received 2 March 2011; revised 8 April 2011; accepted 10 May 2011; published 17 August 2011. The authors would like to thank all members of the GABRIEL Science team for their provision of the aircraft data. We would also like to thank Lee Murray (Harvard University) for his help with the local lightning distribution and Daniel Stone and Mat Evans (University of Leeds) for their help setting up the box model. The GEOS‐Chem model is managed at Harvard University with support from the NASA Atmospheric Chemistry Modeling and Analysis Program. This work was supported by the Natural Environment Research Council (NERC research grants NE/G013810/1 and NE/D001471). A.A. and D.H. acknowledge support from the Swedish Research Council Formas.
Funding AgencyGrant Number
Natural Environment Research Council (NERC)NE/G013810/1
Natural Environment Research Council (NERC)NE/D001471
Swedish Research Council FormasUNSPECIFIED
Subject Keywords:Amazon; GEOS-Chem; OMI; SCIAMACHY; formaldehyde; isoprene
Record Number:CaltechAUTHORS:20110909-153101927
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Official Citation:Barkley, M. P., et al. (2011), Can a “state of the art” chemistry transport model simulate Amazonian tropospheric chemistry?, J. Geophys. Res., 116, D16302, doi:10.1029/2011JD015893.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:25281
Deposited By: Ruth Sustaita
Deposited On:09 Sep 2011 23:01
Last Modified:09 Mar 2020 13:19

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