Amazon boundary layer aerosol concentration sustained by vertical transport during rainfall

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Wang, Jian ; Krejci, Radovan ; Giangrandel, Scott ; Kuang, Chongai ; Barbosa, Henrique M. J. ; Brito, Joel ; Carbone, Samara ; Chi, Xuguang ; Comstock, Jennifer ; Ditas, Florian ; Lavric, Jost ; Manninen, Hanna E. ; Mei, Fan ; Moran-Zuloaga, Daniel ; Poehlker, Christopher ; Poehlker, Mira L. ; Saturno, Jorge ; Schmid, Beat ; Souza, Rodrigo A. F. ; Springston, Stephen R. ; Tomlinson, Jason M. ; Toto, Tami ; Walter, David ; Wimmer, Daniela ; Smith, James N. ; Kulmala, Markku ; Machado, Luiz A. T. ; Artaxo, Paulo ; Andreae, Meinrat O. ; Petaja, Tuukka ; Martin, Scot T.

• Tipo de documento: Artigo Científico
• Fonte: Nature; v. 539, n. 7629, p. 416-419, NOV 17 2016.
• Citações Web of Science: 34

Resumo

The nucleation of atmospheric vapours is an important source of new aerosol particles that can subsequently grow to form cloud condensation nuclei in the atmosphere(1). Most field studies of atmospheric aerosols over continents are influenced by atmospheric vapours of anthropogenic origin (for example, ref. 2) and, in consequence, aerosol processes in pristine, terrestrial environments remain poorly understood. The Amazon rainforest is one of the few continental regions where aerosol particles and their precursors can be studied under near-natural conditions(3-5), but the origin of small aerosol particles that grow into cloud condensation nuclei in the Amazon boundary layer remains unclear(6-8). Here we present aircraft- and ground-based measurements under clean conditions during the wet season in the central Amazon basin. We find that high concentrations of small aerosol particles (with diameters of less than 50 nanometres) in the lower free troposphere are transported from the free troposphere into the boundary layer during precipitation events by strong convective downdrafts and weaker downward motions in the trailing stratiform region. This rapid vertical transport can help to maintain the population of particles in the pristine Amazon boundary layer, and may therefore influence cloud properties and climate under natural conditions. (AU)

• Processo FAPESP: 13/05014-0 - GoAmazon: interação da pluma urbana de Manaus com emissões biogênicas da Floresta Amazônica
• Beneficiário: Paulo Eduardo Artaxo Netto
• Linha de fomento: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático
• Processo FAPESP: 09/15235-8 - Processos de nuvens associados aos principais sistemas precipitantes no Brasil: uma contribuição à modelagem da escala de nuvens e ao GPM (Medida Global de Precipitação)
• Beneficiário: Luiz Augusto Toledo Machado
• Linha de fomento: Auxílio à Pesquisa - Temático
• Processo FAPESP: 13/50510-5 - Pesquisa colaborativa Brasil-EUA: modificações causadas pela poluição antrópica na química da atmosfera e na microfísica de partículas da floresta tropical durante as campanhas intensivas do GoAmazon
• Beneficiário: Henrique de Melo Jorge Barbosa
• Linha de fomento: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Regular