ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-10-11415-2010 An overview of the Amazonian Aerosol Characterization Experiment 2008 (AMAZE-08) Martin S. T. 1 Andreae M. O. 2 Althausen D. 3 Artaxo P. 4 Baars H. 3 Borrmann S. 2 Chen Q. 1 Farmer D. K. 5 Guenther A. 6 Gunthe S. S. 2 Jimenez J. L. 5 Karl T. 6 Longo K. 7 Manzi A. 8 Müller T. 3 Pauliquevis T. 9 14 Petters M. D. 10 Prenni A. J. 11 Pöschl U. 2 Rizzo L. V. 4 Schneider J. 2 Smith J. N. 6 Swietlicki E. 12 Tota J. 8 Wang J. 13 Wiedensohler A. 3 Zorn S. R. 2 School of Engineering and Applied Sciences and Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts, USA Max Planck Institute for Chemistry, Mainz, Germany Leibniz Institute for Tropospheric Research, Leipzig, Germany Institute of Physics, University of São Paulo, Brazil Department of Chemistry and Biochemistry and Cooperative Institute for Research in the Environmental Sciences, University of Colorado, Boulder, Colorado, USA NCAR Earth System Laboratory, National Center for Atmospheric Research, Boulder, Colorado, USA Center of Weather Forecast and Climatic Studies (CPTEC-INPE), Cachoeira Paulista, São Paulo, Brazil National Institute of Amazonian Research (INPA), Manaus, Brazil Institute of Astronomy, Geophysics and Atmospheric Science, University of São Paulo, Brazil Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina, USA Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado, USA Department of Physics, Lund University, Lund, Sweden Department of Earth and Atmospheric Sciences, University of Nebraska, Lincoln, Nebraska, USA now at: Earth and Natural Sciences Department, Federal University of Sao Paulo at Diadema, Diadema, Brazil 02 12 2010 10 23 11415 11438 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/10/11415/2010/acp-10-11415-2010.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/10/11415/2010/acp-10-11415-2010.pdf

The Amazon Basin provides an excellent environment for studying the sources, transformations, and properties of natural aerosol particles and the resulting links between biological processes and climate. With this framework in mind, the Amazonian Aerosol Characterization Experiment (AMAZE-08), carried out from 7 February to 14 March 2008 during the wet season in the central Amazon Basin, sought to understand the formation, transformations, and cloud-forming properties of fine- and coarse-mode biogenic aerosol particles, especially as related to their effects on cloud activation and regional climate. Special foci included (1) the production mechanisms of secondary organic components at a pristine continental site, including the factors regulating their temporal variability, and (2) predicting and understanding the cloud-forming properties of biogenic particles at such a site. In this overview paper, the field site and the instrumentation employed during the campaign are introduced. Observations and findings are reported, including the large-scale context for the campaign, especially as provided by satellite observations. New findings presented include: (i) a particle number-diameter distribution from 10 nm to 10 μm that is representative of the pristine tropical rain forest and recommended for model use; (ii) the absence of substantial quantities of primary biological particles in the submicron mode as evidenced by mass spectral characterization; (iii) the large-scale production of secondary organic material; (iv) insights into the chemical and physical properties of the particles as revealed by thermodenuder-induced changes in the particle number-diameter distributions and mass spectra; and (v) comparisons of ground-based predictions and satellite-based observations of hydrometeor phase in clouds. A main finding of AMAZE-08 is the dominance of secondary organic material as particle components. The results presented here provide mechanistic insight and quantitative parameters that can serve to increase the accuracy of models of the formation, transformations, and cloud-forming properties of biogenic natural aerosol particles, especially as related to their effects on cloud activation and regional climate.

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