Emission and Chemistry of Volatile Organic Compounds (VOCs) as Observed at T3: Contrast of the Dry and Wet Seasons

Wednesday, 16 December 2015
Poster Hall (Moscone South)
Yingjun Liu1, Karena A McKinney1, Thomas B Watson2, Stephen R. Springston2, Roger Seco3, Jeong-Hoo Park4, Saewung Kim5, John E Shilling6, Alex B Guenther5, Lindsay Yee7, Gabriel A Isaacman-VanWertz7, Rebecca Ann Wernis7, Allen H Goldstein7, Joel Brito8, Paulo Artaxo9, Rodrigo Augusto Ferreira de Souza10, Antonio O Manzi11 and Scot T Martin1, (1)Harvard University, Cambridge, MA, United States, (2)Brookhaven National Laboratory, Upton, NY, United States, (3)University of California Irvine, Dept. of Earth System Science, Irvine, CA, United States, (4)NIER National Institute of Environmental Research, Incheon, South Korea, (5)University of California Irvine, Irvine, CA, United States, (6)Pacific Northwest National Laboratory, Richland, WA, United States, (7)University of California Berkeley, Berkeley, CA, United States, (8)Universidade de São Paulo, Instituto de Física, São Paulo, Brazil, (9)USP University of Sao Paulo, São Paulo, Brazil, (10)Organization Not Listed, Washington, DC, United States, (11)National Institute for Amazon Research (INPA), Manaus, AM, Brazil
Tropical rainforests are vigorous emitters of volatile organic compounds (VOCs) year round. Despite the small seasonal variation expected for tropical rainforests, converging evidence has shown that, among other factors, there can be considerable differences between the wet and dry seasons in leaf coverage, species composition, leaf-level photosynthetic photo flux, and ozone and NOx levels, which are important controlling factors of VOC emission and chemistry. There have been, however, a limited number of studies on the seasonality of VOC concentrations over tropical rainforests. As part of the GoAmazon 2014/5 Experiment, two-month continuous measurements of VOC compounds were carried out using a proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) at the T3 site in both the wet and dry seasons of 2014. During the dry season most biogenic VOC species and their oxidation products exhibited increased concentration. For some species, the diel pattern was also different between the two seasons. Implications of the seasonality of the emission and chemistry of biogenic VOCs, in particular isoprene and terpenes, are discussed.