Aerosol particles from tropical convective systems: Cloud tops and cirrus anvils

Tomoko Kojima, P R Buseck, James C. Wilson, J. Michael Reeves, Michael J. Mahoney

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36 Scopus citations

Abstract

Aerosol particles from the upper troposphere (UT) and lower stratosphere (LS) were collected during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) and studied by transmission electron microscopy (TEM). Samples were classified into three categories: (1) UT in-cloud, (2) UT out-of-cloud, and (3) LS. Sulfate particles, including former H2SO4 droplets, are dominant in samples from all categories. The morphology of H2SO4 droplets indicates that they had been ammoniated to some extent at the time of collection. They are internally mixed with organic materials, metal sulfates, and solid particles of various compositions. K- and S-bearing organic particles and Si-Al-rich particles are common to the three kinds of samples. In-cloud samples contain abundant Zn-rich particles. Their origin is unclear, but it seems likely that they are contaminants that originated through impact by ice cloud particles on the aircraft or sampling system. Ammoniation and internal mixing of H2SO4 in the UT aerosols may result in freezing at higher temperature than in pure H2SO4 aerosols. The relatively high extent of ammoniation in the UT in-cloud samples may have resulted from vertical transport of ammonia by strong convection. Abundances of nonsulfate particles decrease with increasing altitudes. The nonsulfate particles originated from the lower troposphere and were transported to the UT and LS.

Original languageEnglish (US)
Pages (from-to)D12201 1-11
JournalJournal of Geophysical Research D: Atmospheres
Volume109
Issue number12
DOIs
StatePublished - Jun 27 2004

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Keywords

  • Cirrus clouds
  • Ice nucleation
  • Lower stratosphere
  • Sulfuric acid
  • Transmission electron microscopy
  • Upper troposphere

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

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