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@Article{SantosLGKGOFLHBF:2018:BiBuEm,
               author = "Santos, Fernando and Longo, Karla Maria and Gunther, Alex and Kim, 
                         Saewung and Gu, Dasa and Oram, Dave and Forster, Grant and Lee, 
                         James and Hopkins, James and Brito, Joel and Freitas, Saulo",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {NASA 
                         Goddard Space Flight Center} 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 {University of York} and {Universidade 
                         de S{\~a}o Paulo (USP)} and {NASA Goddard Space Flight Center}",
                title = "Biomass burning emission disturbances of isoprene oxidation in a 
                         tropical forest",
              journal = "Atmospheric Chemistry and Physics",
                 year = "2018",
               volume = "18",
               number = "17",
                pages = "12715--12734",
                month = "Sept.",
             abstract = "We present a characterization of the chemical composition of the 
                         atmosphere of the Brazilian Amazon rainforest based on trace gas 
                         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), nitrogen oxides (NOx), ozone 
                         (O-3), isoprene, and its main oxidation products, methyl vinyl 
                         ketone (MVK), methacrolein (MACR), and isoprene hydroxy 
                         hydroperoxide (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 ([O-3] / 
                         [CO]), to evaluate the impact of biomass burning emissions on 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) downwind. The oxidation of isoprene is higher in 
                         fresh smoke plumes at lower altitudes (similar to 500 m) than in 
                         aged smoke plumes, anticipating near the surface a complex chain 
                         of oxidation reactions which may be related to secondary organic 
                         aerosol (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 on the same order of magnitude 
                         of a recent observation in the Amazon rainforest [OH] congruent to 
                         10(6) (molecules cm(-3)). During the fresh plume regime, the 
                         vertical profile of [OH] and the [MVK + MACR + ISOPOOH] / 
                         [isoprene] ratio showed evidence of an increase in the oxidizing 
                         power in the transition from planetary boundary layer to cloud 
                         layer (1000-1500 m). These high values of [OH] (1.5 x 10(6) 
                         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-18-12715-2018",
                  url = "http://dx.doi.org/10.5194/acp-18-12715-2018",
                 issn = "1680-7316 and 1680-7324",
                label = "self-archiving-INPE-MCTIC-GOV-BR",
             language = "en",
           targetfile = "santos_biomass.pdf",
        urlaccessdate = "28 nov. 2020"
}


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