Aerosol and gas re-distribution by shallow cumulus clouds: An investigation using airborne measurements

Wonaschuetz Anna Wonaschuetz, Armin Sorooshian, Barbara Ervens, Patrick Y. Chuang, Graham Feingold, Shane M. Murphy, Joost De Gouw, Carsten Warneke, Haflidi H. Jonsson

Research output: Contribution to journalArticle

35 Scopus citations

Abstract

Aircraft measurements during the 2006 Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) are used to examine the influence of shallow cumulus clouds on vertical profiles of aerosol chemical composition, size distributions, and secondary aerosol precursor gases. The data show signatures of convective transport of particles, gases and moisture from near the surface to higher altitudes, and of aqueous-phase production of aerosol mass (sulfate and organics) in cloud droplets and aerosol water. In cloudy conditions, the average aerosol volume concentration at an altitude of 2850 m, above typical cloud top levels, was found to be 34% of that at 450 m; for clear conditions, the same ratio was 13%. Both organic and sulfate mass fractions were on average constant with altitude (around 50%); however, the ratio of oxalate to organic mass increased with altitude (from 1% at 450 m to almost 9% at 3450 m), indicative of the influence of in-cloud production on the vertical abundance and characteristics of secondary organic aerosol (SOA) mass. A new metric termed "residual cloud fraction" is introduced as a way of quantifying the "cloud processing history" of an air parcel. Results of a parcel model simulating aqueous phase production of sulfate and organics reproduce observed trends and point at a potentially important role of SOA production, especially oligomers, in deliquesced aerosols. The observations emphasize the importance of shallow cumulus clouds in altering the vertical distribution of aerosol properties that influence both their direct and indirect effect on climate.

Original languageEnglish (US)
Article numberD17202
JournalJournal of Geophysical Research Atmospheres
Volume117
Issue number17
DOIs
StatePublished - Jan 1 2012

    Fingerprint

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

Cite this

Anna Wonaschuetz, W., Sorooshian, A., Ervens, B., Chuang, P. Y., Feingold, G., Murphy, S. M., De Gouw, J., Warneke, C., & Jonsson, H. H. (2012). Aerosol and gas re-distribution by shallow cumulus clouds: An investigation using airborne measurements. Journal of Geophysical Research Atmospheres, 117(17), [D17202]. https://doi.org/10.1029/2012JD018089