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- Title
Hydroperoxyl radical measurements at the canopy-atmosphere interface in the Amazon rainforest.
- Authors
Mallik, Chinmay; Acevedo, Otávio C.; Araùjo, Alessandro; Berger, Martina; Bourtsoukidis, Efstratios; Dlugi, Ralph; Kesselmeier, Jürgen; Lelieveld, Jos; Manzi, Antonio Ocimar; Marno, Daniel; Martinez, Monica; Oliveira, Pablo E. S.; Pfannerstill, Eva; Sörgel, Matthias; Tauer, Sebastian; Tsokankunku, Anywhere; Sá, Marta; Yáñez-Serrano, Ana-Maria; Williams, Jonathan; Wolff, Stefan
- Abstract
Hydroperoxyl radicals (HO2) account for bulk of the HOx number density and together with the hydroxyl radicals (OH) maintain the self-cleaning capacity of the atmosphere. The reaction of HO2 with NO forming NO2 is an important chemical source of tropospheric O3, which is a greenhouse gas detrimental to the health of humans and plants. The oxidation of CO and hydrocarbons emitted from various anthropogenic and biogenic processes lead to the formation of HO2. The chemical lifetime of HO2 is about a few hundred seconds, sufficient to feed oxidation processes and interact with turbulences in the microscale e.g. HO2 formed due to oxidation of biogenic hydrocarbons above forest canopies can be transported down into the canopies and react with NO and O3 to recycle OH.The vast green stretches of Amazon are not only a storehouse of carbon but also the source of copious biogenic hydrocarbons, which impact the regional and global atmospheric chemistry. The export of primary hydrocarbons and their oxidized products from the Amazon to the global troposphere depends on the oxidation capacity at the canopy-atmosphere interface. To understand the chemical processes influencing the oxidation capacity over the Amazons, measurements of OH, HO2 along with related chemical, meteorological and photochemical parameters were carried out during an intensive field campaign SEGAM (SEGregation experiment in the AMazon) in November 2015. Fast 5 Hz measurements of OH and HO2 using laser induced fluorescence were conducted on a tower at 40 m altitude at the canopy-atmosphere interface to understand the sources, sinks and chemistry of atmospheric oxidants in relation to the variation in NO and isoprene fluxes down in the forest. This presentation deals with the measured variability of HO2 during SEGAM and its chemical sources and sinks estimated with a photochemical box model.
- Subjects
ATMOSPHERIC chemistry; CHEMICAL processes; SINKS (Atmospheric chemistry); LASER-induced fluorescence; THROUGHFALL; FOREST canopies
- Publication
Geophysical Research Abstracts, 2019, Vol 21, p1
- ISSN
1029-7006
- Publication type
Article