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Title: Amazon boundary layer aerosol concentration sustained by vertical transport during rainfall

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. Most field studies of atmospheric aerosols over continents are influenced by atmospheric vapours of anthropogenic origin 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, but the origin of small aerosol particles that grow into cloud condensation nuclei in the Amazon boundary layer remains unclear. 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. Lastly, 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.
 [1] ;  [2] ;  [1] ;  [1] ;  [3] ;  [3] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [5] ;  [6] ;  [6] ;  [6] ;  [6] ;  [5] ;  [9] ;  [1] more »;  [5] ;  [1] ;  [6] ;  [8] ;  [10] ;  [8] ;  [11] ;  [3] ;  [12] ;  [8] ;  [13] « less
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Stockholm Univ. (Sweden). Dept. of Applied Environmental Science and Analytical Chemistry
  3. Univ. of Sao Paulo (Brazil)
  4. Max Planck Inst. for Chemistry, Mainz (Germany). Biogeochemistry and Multiphase Chemistry Departments; Nanjing Univ. and Collaborative Innovation Center for Climate Change, Nanjing (China). School of Atmospheric Sciences
  5. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Atmospheric Science and Global Change Div. (ASGC)
  6. Max Planck Inst. for Chemistry, Mainz (Germany). Biogeochemistry and Multiphase Chemistry Departments
  7. Max Planck Inst. for Biogeochemistry, Jena (Germany)
  8. Univ. of Helsinki (Finland). Dept. of Physics
  9. Amazonas State Univ., Amazonas (Brazil)
  10. Univ. of California, Irvine, CA (United States). Dept. of Chemistry
  11. National Inst. for Space Research, Sao Jose dos Campos, Sao Paulo (Brazil)
  12. Max Planck Inst. for Chemistry, Mainz (Germany). Biogeochemistry and Multiphase Chemistry Departments; Univ. of California, San Diego, CA (United States). Scripps Inst. of Oceanography
  13. Harvard Univ., Cambridge, MA (United States). School of Engineering and Applied Sciences (SEAS). Dept. of Earth and Planetary Sciences
Publication Date:
Report Number(s):
Journal ID: ISSN 0028-0836; R&D Project: 2016-BNL-EE630EECA-Budg; KP1701000
Grant/Contract Number:
SC0012704; AC02-98CH10886
Accepted Manuscript
Journal Name:
Nature (London)
Additional Journal Information:
Journal Name: Nature (London); Journal Volume: 539; Journal Issue: 7629; Journal ID: ISSN 0028-0836
Nature Publishing Group
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
OSTI Identifier: