@Article{SantosLGKGOFLHBF:2017:BiBuEm,
               author = "Santos, Fernando Cavalcante dos and Longo, Karla Maria and 
                         Guenther, Alex B. and Kim, Saewung and Gu, Dasa and Oram, Dave E. 
                         and Forster, Grant L. and Lee, James and Hopkins, James R. and 
                         Brito, Joel F. and Freitas, Saulo R.",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {University of 
                         California} and {University of California} and {University of 
                         California} and {University of East Anglia} and {University of 
                         East Anglia} and {University of York} and {University of York} and 
                         {Universidade de S{\~a}o Paulo (USP)} and {NASA Goddard Space 
                         Flight Center}",
                title = "Biomass burning emissions disturbances on the isoprene oxidation 
                         in a tropical forest",
              journal = "Atmospheric Chemistry and Physics Discussion",
                 year = "2017",
               volume = "1083",
                pages = "1--35",
             abstract = "We present a characterization of the chemical composition of the 
                         atmosphere of the Brazilian Amazon rainforest based on trace gases 
                         measurements carried out during the South American Biomass Burning 
                         Analysis (SAMBBA) airborne experiment in September 2012. We 
                         analyzed the observations of primary biomass burning emission 
                         tracers, i.e., carbon monoxide (CO) and nitrogen oxides (NOx), 
                         ozone (O3), isoprene, and its main oxidation products, methyl 
                         vinyl ketone (MVK), methacrolein (MACR), and hydroxyhydroperoxides 
                         (ISOPOOH). The focus of SAMBBA was primarily on biomass burning 
                         emissions, but there were also several flights in areas of the 
                         Amazon forest not directly affected by biomass burning, revealing 
                         a background with a signature of biomass burning in the chemical 
                         composition due to long-range transport of biomass burning tracers 
                         from both Africa and the eastern part of Amazonia. We used the 
                         [MVK+MACR+ ISOPOOH]/[Isoprene] ratio and the hydroxyl radical (OH) 
                         indirect calculation to assess the oxidative capacity of the 
                         Amazon forest atmosphere. We compared the background regions 
                         (CO<150 ppbv), fresh and aged smoke plumes classified according to 
                         their photochemical age ([O3]/[CO]), to evaluate the impact of 
                         biomass burning emissions in the oxidative capacity of the Amazon 
                         forest atmosphere. We observed that biomass burning emissions 
                         disturb the isoprene oxidation reactions, especially for fresh 
                         plumes ([MVK+MACR+ISOPOOH]/[isoprene] = 7). The oxidation of 
                         isoprene is higher in fresh smoke plumes at lower altitudes (~ 500 
                         m) than in aged smoke plumes, anticipating near the surface a 
                         complex chain of oxidation reactions, which may be related to the 
                         secondary organic aerosols (SOA) formation. We proposed a 
                         refinement of the OH calculation based on the sequential reaction 
                         model, which considers vertical and horizontal transport for both 
                         biomass burning regimes and background environment. Our approach 
                         for the [OH] estimation resulted in values of the same order of 
                         magnitude of a recent observation in the Amazon rainforest [OH] 
                         \≅ 106 (molecules cm-3 ). During the fresh plume regime, 
                         the vertical profile of [OH] and the [MVK+MACR+ISOPOOH]/[isoprene] 
                         ratio showed an evidence of an increase of the oxidizing power in 
                         the transition from PBL to cloud layer (1,000 1,500 m). These high 
                         values of [OH] (1.5 \ 106 molecules cm-3 ) and 
                         [MVK+MACR+ISOPOOH]/[isoprene] (7.5) indicate a significant change 
                         above and inside the cloud decks due to cloud edge effects on 
                         photolysis rates, which have a major impact on OH production 
                         rates.",
                  doi = "10.5194/acp-2017-1083",
                  url = "http://dx.doi.org/10.5194/acp-2017-1083",
                 issn = "1680-7367",
             language = "en",
           targetfile = "santos_biomass.pdf",
        urlaccessdate = "26 abr. 2024"
}