@Article{AlvesJTJYKTNGSMAMG:2016:SeIsEm,
               author = "Alves, Eliane G. and Jardine, Kolby and Tota, Julio and Jardine, 
                         Angela and Y{\~a}nez-Serrano, Ana Maria and Karl, Thomas and 
                         Tavares, Julia and Nelson, Bruce and Gu, Dasa and Stavrakou, 
                         Trissevgeni and Martin, Scot and Artaxo, Paulo and Manzi, Antonio 
                         Ocimar and Guenther, Alex",
          affiliation = "{Instituto Nacional de Pesquisas da Amaz{\^o}nia (INPA)} and 
                         {Lawrence Berkeley National Laboratory (LBNL)} and {Universidade 
                         Federal do Oeste do Par{\'a} (UFOPA)} and {Instituto Nacional de 
                         Pesquisas da Amaz{\^o}nia (INPA)} and {Instituto Nacional de 
                         Pesquisas da Amaz{\^o}nia (INPA)} and {University of Innsbruck} 
                         and {Instituto Nacional de Pesquisas da Amaz{\^o}nia (INPA)} and 
                         {Instituto Nacional de Pesquisas da Amaz{\^o}nia (INPA)} and 
                         {University of California} and {Belgian Institute for Space 
                         Aeronomy} and {Harvard University} and {Universidade de S{\~a}o 
                         Paulo (USP)} and {Instituto Nacional de Pesquisas Espaciais 
                         (INPE)} and {University of California}",
                title = "Seasonality of isoprenoid emissions from a primary rainforest 
                         in\ central Amazonia",
              journal = "Atmospheric Chemistry and Physics",
                 year = "2016",
               volume = "16",
               number = "6",
                pages = "3903--3925",
             abstract = "Tropical rainforests are an important source of isoprenoid and 
                         other volatile organic compound (VOC) emissions to the atmosphere. 
                         The seasonal variation of these compounds is however still poorly 
                         understood. In this study, vertical profiles of mixing ratios of 
                         isoprene, total monoterpenes and total sesquiterpenes, were 
                         measured within and above the canopy, in a primary rainforest in 
                         central Amazonia, using a proton transfer reaction mass 
                         spectrometer (PTR-MS). Fluxes of these compounds from the canopy 
                         into the atmosphere were estimated from PTR-MS measurements by 
                         using an inverse Lagrangian transport model. Measurements were 
                         carried out continuously from September 2010 to January 2011, 
                         encompassing the dry and wet seasons. Mixing ratios were higher 
                         during the dry (isoprene 2.68 ± 0.9 ppbv, total monoterpenes 0.67 
                         ± 0.3 ppbv; total sesquiterpenes 0.09 ± 0.07 ppbv) than the wet 
                         season (isoprene 1.66 ± 0.9 ppbv, total monoterpenes 0.47 ± 0.2 
                         ppbv; total sesquiterpenes 0.03±0.02 ppbv) for all compounds. 
                         Ambient air temperature and photosynthetically active radiation 
                         (PAR) behaved similarly. Daytime isoprene and total monoterpene 
                         mixing ratios were highest within the canopy, rather than near the 
                         ground or above the canopy. By comparison, daytime total 
                         sesquiterpene mixing ratios were highest near the ground. Daytime 
                         fluxes varied signifi- cantly between seasons for all compounds. 
                         The maximums for isoprene (2.53 ± 0.5 µmol m\−2 h 
                         \−1 ) and total monoterpenes (1.77 ± 0.05 µmol m\−2 
                         h \−1 ) were observed in the late dry season, whereas the 
                         maximum for total sesquiterpenes was found during the dry-to-wet 
                         transition season (0.77 ± 0.1 µmol m\−2 h \−1 ). 
                         These flux estimates suggest that the canopy is the main source of 
                         isoprenoids emitted into the atmosphere for all seasons. However, 
                         uncertainties in turbulence parameterization near the ground could 
                         affect estimates of fluxes that come from the ground. Leaf 
                         phenology seemed to be an important driver of seasonal variation 
                         of isoprenoid emissions. Although remote sensing observations of 
                         changes in leaf area index were used to estimate leaf phenology, 
                         MEGAN 2.1 did not fully capture the behavior of seasonal emissions 
                         observed in this study. This could be a result of very local 
                         effects on the observed emissions, but also suggest that other 
                         parameters need to be better determined in biogenic volatile 
                         organic compound (BVOC) models. Our results support established 
                         findings that seasonality of isoprenoids are driven by seasonal 
                         changes in light, temperature and leaf phenology. However, they 
                         suggest that leaf phenology and its role on isoprenoid production 
                         and emission from tropical plant species needs to be better 
                         understood in order to develop mechanistic explanations for 
                         seasonal variation in emissions. This also may reduce the 
                         uncertainties of model estimates associated with the responses to 
                         environmental factors. Therefore, this study strongly encourages 
                         long-term measurements of isoprenoid emissions, environmental 
                         factors and leaf phenology from leaf to ecosystem scale, with the 
                         purpose of improving BVOC model approaches that can characterize 
                         seasonality of isoprenoid emissions from tropical rainforests.",
                  doi = "10.5194/acp-16-3903-2016",
                  url = "http://dx.doi.org/10.5194/acp-16-3903-2016",
                 issn = "1680-7324",
                label = "lattes: 0575383574431005 13 AlvesJTJYKTNGSMAMG:2016:SeIsEm",
             language = "en",
           targetfile = "alves_seasonality.pdf",
        urlaccessdate = "10 maio 2024"
}