Vertical structure of aerosols, temperature, and moisture associated with an intense African dust event observed over the eastern Caribbean

Eunsil Jung, Bruce Albrecht, Joseph M. Prospero, Haflidi H. Jonsson, Sonia M. Kreidenweis

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

An unusually intense African dust event affected a large area of the western Atlantic and eastern Caribbean in early April 2010. Measurements made east of Barbados from the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter research aircraft are used to characterize particle size distributions; vertical distributions of aerosols, temperature, and moisture; and processes leading to the observed stratification in the boundary layer. The vertical profiles of various aerosol characterizations were similar on both days and show three layers with distinct aerosol and thermodynamic characteristics: the Saharan Air Layer (SAL; ~2.2 km ± 500 m), a subcloud layer (SCL; surface to ~500 m), and an intermediate layer extending between them. The SAL and SCL display well-mixed aerosol and thermodynamic characteristics; but the most significant horizontal and vertical variations in aerosols and thermodynamics occur in the intermediate layer. The aerosol variability observed in the intermediate layer is likely associated with modification by shallow cumulus convection occurring sometime in the prior history of the air mass as it is advected across the Atlantic. A comparison of the thermodynamic structure observed in the event from its origin over Africa with that when it reached Barbados indicates that the lower part of the SAL was moistened by surface fluxes as the air mass was advected across the Atlantic. Mixing diagrams using aerosol concentrations and water vapor mixing ratios as conserved parameters provide insight into the vertical transports and mixing processes that may explain the observed aerosol and thermodynamic variability in each layer. Key Points Vertical structure and characteristics of SALChanges in PSD due to the cloud processingVertical transports and mixing processes of dust

Original languageEnglish (US)
Pages (from-to)4623-4643
Number of pages21
JournalJournal of Geophysical Research Atmospheres
Volume118
Issue number10
DOIs
StatePublished - May 27 2013

Keywords

  • Barbados
  • SAL
  • aerosol PSD
  • aerosol vertical transport
  • cloud processing

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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