TY - JOUR
T1 - Downward transport of ozone rich air and implications for atmospheric chemistry in the Amazon rainforest
AU - Gerken, Tobias
AU - Wei, Dandan
AU - Chase, Randy J.
AU - Fuentes, Jose D.
AU - Schumacher, Courtney
AU - Machado, Luiz A.T.
AU - Andreoli, Rita V.
AU - Chamecki, Marcelo
AU - Ferreira de Souza, Rodrigo A.
AU - Freire, Livia S.
AU - Jardine, Angela B.
AU - Manzi, Antonio O.
AU - Nascimento dos Santos, Rosa M.
AU - von Randow, Celso
AU - dos Santos Costa, Patrícia
AU - Stoy, Paul C.
AU - Tóta, Julio
AU - Trowbridge, Amy M.
PY - 2016/1/1
Y1 - 2016/1/1
N2 - From April 2014 to January 2015, ozone (O3) dynamics were investigated as part of GoAmazon 2014/5 project in the central Amazon rainforest of Brazil. Just above the forest canopy, maximum hourly O3 mixing ratios averaged 20 ppbv (parts per billion on a volume basis) during the June-September dry months and 15 ppbv during the wet months. Ozone levels occasionally exceeded 75 ppbv in response to influences from biomass burning and regional air pollution. Individual convective storms transported O3-rich air parcels from the mid-troposphere to the surface and abruptly enhanced the regional atmospheric boundary layer by as much as 25 ppbv. In contrast to the individual storms, days with multiple convective systems produced successive, cumulative ground-level O3 increases. The magnitude of O3 enhancements depended on the vertical distribution of O3 within storm downdrafts and origin of downdrafts in the troposphere. Ozone mixing ratios remained enhanced for > 2 h following the passage of storms, which enhanced chemical processing of rainforest-emitted isoprene and monoterpenes. Reactions of isoprene and monoterpenes with O3 are modeled to generate maximum hydroxyl radical formation rates of 6×106 radicals cm-3s-1. Therefore, one key conclusion of the present study is that downdrafts of convective storms are estimated to transport enough O3 to the surface to initiate a series of reactions that reduce the lifetimes of rainforest-emitted hydrocarbons.
AB - From April 2014 to January 2015, ozone (O3) dynamics were investigated as part of GoAmazon 2014/5 project in the central Amazon rainforest of Brazil. Just above the forest canopy, maximum hourly O3 mixing ratios averaged 20 ppbv (parts per billion on a volume basis) during the June-September dry months and 15 ppbv during the wet months. Ozone levels occasionally exceeded 75 ppbv in response to influences from biomass burning and regional air pollution. Individual convective storms transported O3-rich air parcels from the mid-troposphere to the surface and abruptly enhanced the regional atmospheric boundary layer by as much as 25 ppbv. In contrast to the individual storms, days with multiple convective systems produced successive, cumulative ground-level O3 increases. The magnitude of O3 enhancements depended on the vertical distribution of O3 within storm downdrafts and origin of downdrafts in the troposphere. Ozone mixing ratios remained enhanced for > 2 h following the passage of storms, which enhanced chemical processing of rainforest-emitted isoprene and monoterpenes. Reactions of isoprene and monoterpenes with O3 are modeled to generate maximum hydroxyl radical formation rates of 6×106 radicals cm-3s-1. Therefore, one key conclusion of the present study is that downdrafts of convective storms are estimated to transport enough O3 to the surface to initiate a series of reactions that reduce the lifetimes of rainforest-emitted hydrocarbons.
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U2 - 10.1016/j.atmosenv.2015.11.014
DO - 10.1016/j.atmosenv.2015.11.014
M3 - Article
AN - SCOPUS:84947814910
VL - 124
SP - 64
EP - 76
JO - Atmospheric Environment
JF - Atmospheric Environment
SN - 1352-2310
ER -