A31A-0014
The Interaction between Surface-Atmosphere Exchange and Convective Precipitation in the Amazon: Results of the GoAmazon Boundary Layer Experiment
Wednesday, 16 December 2015
Poster Hall (Moscone South)
Paul C Stoy1, Jose D Fuentes2, Tobias Gerken2, Amy Trowbridge1, Gabriel George Katul3, Rosa M Nascimento dos Santos4, Antonio O Manzi5, Juliane Mercer1, Luiz Machado6, Julio Tota7, Celso von Randow8, Gilberto Fisch6, Fernando Ramos6 and Marcelo Chamecki9, (1)Montana State University, Bozeman, MT, United States, (2)Pennsylvania State University Main Campus, University Park, PA, United States, (3)Duke University, Durham, NC, United States, (4)Universidade do Estado do Amazonas, Manaus, Brazil, (5)National Institute for Amazon Research (INPA), Manaus, AM, Brazil, (6)INPE National Institute for Space Research, Sao Jose dos Campos, Brazil, (7)Federal University of Western Para, Santarem, Brazil, (8)Instituto Nacional de Pesquisas Espaciais, São José dos Campos, Brazil, (9)Pennsylvania State University Main Campus, Department of Meteorology, University Park, PA, United States
Abstract:
We describe results from a field campaign in central Amazonia whose purpose is to quantify the relationship between the surface-atmosphere exchange of biogenic volatile organic compounds (BVOCs) and convective precipitation as mediated by turbulent transport and the production of secondary organic aerosols and cloud condensation nuclei. The chemical speciation of monoterpenes and sesquiterpines emitted by the rainforest were determined using gas chromatography-mass spectroscopy and proton transfer-reaction mass spectroscopy enabled quantification of the concentrations of monoterpenes, sesquiterpenes, and other BVOCs. The temporal and spatial evolution of BVOCs and ozone concentrations within and immediately above the forested canopy were quantified and used to estimate the consumption, production, and transport of BVOCs, ozone, and hydroxyl radical during wet and dry seasons. Fluxes were estimated using above and within canopy flow field measurements from ten sonic anemometers and fitted using a second-order closure approach in conjunction with concentration profiles. Results demonstrate bi-directional fluxes of isoprene and monoterpenes in response to local sources and sinks attributed to deposition and chemical transformation in the air space below the upper canopy and transport to the overlying atmosphere. High hydroxyl radical yields (> 106 radicals cm-3 s-1) were estimated from reactions of ozone with ten monoterpene and six sequiterpene species observed to be emitted by the rainforest. Reactions of ozone and hydroxyl radicals dominated the conversion of BVOCs to secondary organic aerosols and cloud condensation nuclei, whose concentrations were measured using a fast mobility particle sizer and a cloud condensation nuclei counter. Results demonstrate that the rainforest emits sufficient chemical species to generate aerosols that can activate into cloud condensation nuclei and influence regional cloud formation.
