Multi-model simulation of CO and HCHO in the Southern Hemisp

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TitleMulti-model simulation of CO and HCHO in the Southern Hemisphere: comparison with observations and impact of biogenic emissionsAbstractWe investigate the impact of biogenic emissions on carbon monoxide (CO) and formaldehyde (HCHO) in the Southern Hemisphere (SH), with simulations using two different biogenic emission inventories for isoprene and monoterpenes. Results from four atmospheric chemistry models are compared to continuous long-term ground-based CO and HCHO column measurements at the SH Network for the Detection of Atmospheric Composition Change (NDACC) sites, the satellite measurement of tropospheric CO columns from the Measurement of Pollution in the Troposphere (MOPITT), and in situ surface CO measurements from across the SH, representing a subset of the National Oceanic and Atmospheric AdministrationÅ› Global Monitoring Division (NOAA GMD) network. Simulated mean model CO using the Model of Emissions of Gases and Aerosols from Nature (v2.1) computed in the frame work of the Land Community Model (CLM-MEGANv2.1) inventory is in better agreement with both column and surface observations than simulations adopting the emission inventory generated from the LPJ-GUESS dynamical vegetation model framework, which markedly underestimate measured column and surface CO at most sites. Differences in biogenic emissions cause large differences in CO in the source regions which propagate to the remote SH. Significant inter-model differences exist in modelled column and surface CO, and secondary production of CO dominates these inter-model differences, due mainly to differences in the models Ìoxidation schemes for volatile organic compounds, predominantly isoprene oxidation. While biogenic emissions are a significant factor in modelling SH CO, inter-model differences pose an additional challenge to constrain these emissions. Corresponding comparisons of HCHO columns at two SH mid-latitude sites reveal that all models significantly underestimate the observed values by approximately a factor of 2. There is a much smaller impact on HCHO of the significantly different biogenic emissions in remote regions, compared to the source regions. Decreased biogenic emissions cause decreased CO export to remote regions, which leads to increased OH; this in turn results in increased HCHO production through methane oxidation. In agreement with earlier studies, we corroborate that significant HCHO sources are likely missing in the models in the remote SH. Copyright Author(s) 2015.AcknowledgementsThis work has been supported by NIWA as part of its Government-funded, core research. We acknowledge the UK Met Office for the use of the Unified Model, the University of Cambridge for the development of UKCA, and the contribution of NeSI high-performance computing facilities to the results of this research. NZÅ› national facilities are provided by the NZ eScience Infrastructure and funded jointly by NeSIÅ› collaborator institutions and through the Ministry of Business, Innovation & EmploymentÅ› Research Infrastructure programme (https://www.nesi.org.nz). JAF was funded by a University of Wollongong Vice ChancellorÅ› Postdoctoral Fellowship, with the assistance of resources provided at the NCI National Facility systems at the Australian National University through the National Computational Merit Allocation Scheme supported by the Australian Government. Jingqiu Mao assisted with implementing the CO25 tracers in GEOS-Chem. The National Centre for Atmospheric Research is operated by the University Corporation for Atmospheric Research with funding from the National Science Foundation. We also acknowledge Antarctica New Zealand, and the Australian Research Council for support (DP110101948).Funding DetailsMBIE, Ministry of Business, Innovation and Employment; NCI, Ministry of Business, Innovation and Employment; NSF, Ministry of Business, Innovation and Employment; UOW, Ministry of Business, Innovation and Employment; Ministry of Business, Innovation and Employment; DP110101948, ARC, Ministry of Business, Innovation and Employment

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1st AuthorZeng, G.AuthorZeng, G.Williams, J.Fisher, J.Emmons, L.Jones, N.Morgenstern, O.Robinson, J.Smale, D.Paton-Walsh, C.Griffith, D.Year2015JournalAtmospheric Chemistry and PhysicsVolume15Number13Pages7217-7245DOI10.5194/acp-15-7217-2015URLhttps://www.scopus.com/inward/recor.....51b7c655ddd8f542aa668e7f9Keywordsatmospheric chemistrybiogenic emissioncarbon monoxidecomparative studyemission inventoryformaldehydeisoprenemonoterpeneSouthern Hemisphere, rank5

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TypeArticleCitationZeng, G., Williams, J., Fisher, J., Emmons, L., Jones, N., Morgenstern, O., Robinson, J., Smale, D., Paton-Walsh, C. and Griffith, D. (2015). Multi-model simulation of CO and HCHO in the Southern Hemisphere: comparison with observations and impact of biogenic emissions. Atmospheric Chemistry and Physics, 15(13): 7217-7245 IdentifierZeng2015Relevancerank5