16 documents found, page 1 of 2
Unexpected seasonality in quantity and composition of Amazon rainforest air rea...
Nölscher, Anke C.; Yáñez-Serrano, Ana Maria; Wolff, Stefan; Araüjo, Alessandro Carioca de; Lavric, J. V.; Kesselmeier, Jürgen; Williams, Jonathan C.The hydroxyl radical (OH) removes most atmospheric pollutants from air. The loss frequency of OH radicals due to the combined effect of all gas-phase OH reactive species is a measureable quantity termed total OH reactivity. Here we present total OH reactivity observations in pristine Amazon rainforest air, as a function of season, time-of-day and height (0-80 m). Total OH reactivity is low during wet (10s-1) an...
The Amazon Tall Tower Observatory (ATTO): Overview of pilot measurements on eco...
Andreae, Meinrat O.; Acevedo, Otávio C.; Araüjo, Alessandro Carioca de; Artaxo, Paulo; Barbosa, Cybelli G.G.; Barbosa, H. M. J.; Brito, Joel F.The Amazon Basin plays key roles in the carbon and water cycles, climate change, atmospheric chemistry, and biodiversity. It has already been changed significantly by human activities, and more pervasive change is expected to occur in the coming decades. It is therefore essential to establish long-term measurement sites that provide a baseline record of present-day climatic, biogeochemical, and atmospheric cond...
Atmospheric mixing ratios of methyl ethyl ketone (2-butanone) in tropical, bore...
Yáñez-Serrano, Ana Maria; Nölscher, Anke C.; Bourtsoukidis, Efstratios; Derstroff, Bettina; Zannoni, Nora; Gros, Valérie; Lanza, Matteo; Brito, Joel F.Methyl ethyl ketone (MEK) enters the atmosphere following direct emission from vegetation and anthropogenic activities, as well as being produced by the gas-phase oxidation of volatile organic compounds (VOCs) such as n-butane. This study presents the first overview of ambient MEK measurements at six different locations, characteristic of forested, urban and marine environments. In order to understand better th...
Dimethyl sulfide in the Amazon rain forest
Jardine, Kolby J.; Yáñez-Serrano, Ana Maria; Williams, Jonathan C.; Kunert, Norbert; Jardine, Angela B.; Taylor, Tyeen C.; Abrell, Leif; Artaxo, PauloSurface-to-atmosphere emissions of dimethyl sulfide (DMS) may impact global climate through the formation of gaseous sulfuric acid, which can yield secondary sulfate aerosols and contribute to new particle formation. While oceans are generally considered the dominant sources of DMS, a shortage of ecosystem observations prevents an accurate analysis of terrestrial DMS sources. Using mass spectrometry, we quantif...
Soil CO2 efflux in central Amazonia: environmental and methodological effects
Zanchi, Fabrício Berton; Waterloo, Maarten J.; Kruijt, Bart J.; Kesselmeier, Jürgen; Luizão, Flávio Jesus; Manzi, Antônio Ocimar; Dolman, Albertus J.Respiração do solo possui um importante papel no ciclo do carbono em florestas tropicais Amazônicas. Entretanto poucas medidas de respiração do solo foram feitas. Neste estudo são apontados os efeitos na metodologia de instalação dos anéis no solo, bem como os efeitos da precipitação e a distribuição espacial da emissão de CO2 na Amazônia central. Os efeitos da inserção de anéis no solo aumentaram de 13 a 20% p...
Acridicon-chuva campaign: Studying tropical deep convective clouds and precipit...
Wendisch, Manfred; Pöschl, Ulrich; Andreae, Meinrat O.; Machado, Luiz Augusto Toledo; Albrecht, Rachel I.; Schlager, Hans; Rosenfeld, DanielComprehensive in situ and remote sensing observations of deep convective clouds using the new German research jet aircraft HALO have been performed over Amazonia to study the influence of anthropogenic aerosols on the cloud life cycle and precipitation formation processes. © 2016 American Meteorological Society.
Aerosol measurement methods to quantify spore emissions from fungi and cryptoga...
Löbs, Nina; Barbosa, Cybelli G.G.; Brill, Sebastian; Walter, David; Ditas, Florian; Oliveira Sá, Marta de; Araüjo, Alessandro Carioca deBioaerosols are considered to play a relevant role in atmospheric processes, but their sources, properties, and spatiotemporal distribution in the atmosphere are not yet well characterized. In the Amazon Basin, primary biological aerosol particles (PBAPs) account for a large fraction of coarse particulate matter, and fungal spores are among the most abundant PBAPs in this area as well as in other vegetated cont...
The effect of flooding on the exchange of the volatile C 2-compounds ethanol, a...
Rottenberger, Stefanie; Kleiss, Betina; Kühn, Uwe; Wolf, Annette; Piedade, Maria Teresa Fernandez; Junk, Wolfgang Johannes; Kesselmeier, JürgenThe effect of root inundation on the leaf emissions of ethanol, acetaldehyde and acetic acid in relation to assimilation and transpiration was investigated with 2ĝ€"3 years old tree seedlings of four Amazonian floodplain species by applying dynamic cuvette systems under greenhouse conditions. Emissions were monitored over a period of several days of inundation using a combination of Proton Transfer Reaction Mas...
Isoprene and monoterpene fluxes from Central Amazonian rainforest inferred from...
Kühn, Uwe; Andreae, Meinrat O.; Ammann, Christoph; Araüjo, Alessandro Carioca de; Brancaleoni, Enzo; Ciccioli, Paolo; Dindorf, TamaraWe estimated the isoprene and monoterpene source strengths of a pristine tropical forest north of Manaus in the central Amazon Basin using three different micrometeorological flux measurement approaches. During the early dry season campaign of the Cooperative LBA Air-borne Regional Experiment (LBA-CLAIRE-2001), a tower-based surface layer gradient (SLG) technique was applied simultaneously with a relaxed eddy a...
Opposite OH reactivity and ozone cycles in the Amazon rainforest and megacity B...
Williams, Jonathan C.; Keßel, Stephan U.; Nölscher, Anke C.; Yang, Yudong; Lee, Yue; Yáñez-Serrano, Ana Maria; Wolff, Stefan; Kesselmeier, JürgenThe Amazon rainforest in Brazil and the megacity of Beijing in China are two of the most strongly contrasting habitats on Earth. In both locations, volatile chemicals are emitted into the atmosphere affecting the local atmospheric chemistry, air quality and ecosystem health. In this study, the total reactivity in air available for reaction with the atmosphere's primary oxidant the OH radical, has been measured ...