@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 = "15 jun. 2024"
}