Water-soluble organic aerosol in the Los Angeles Basin and outflow regions

Airborne and ground measurements during the 2010 CalNex field campaign

Hanh T. Duong, Armin Sorooshian, Jill S. Craven, Scott P. Hersey, Andrew R. Metcalf, Xiaolu Zhang, Rodney J. Weber, Haflidi Jonsson, Richard C. Flagan, John H. Seinfeld

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

A particle-into-liquid sampler coupled to a total organic carbon analyzer (PILS-TOC) quantified particulate water-soluble organic carbon (WSOC) mass concentrations during the May 2010 deployment of the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter in the CalNex field study. WSOC data collected during 16 flights provide the first spatiotemporal maps of WSOC in the San Joaquin Valley, Los Angeles Basin, and outflow regions of the Basin. WSOC was consistently higher in concentration within the Los Angeles Basin, where sea breeze transport and Basin topography strongly influence the spatial distribution of WSOC. The highest WSOC levels were associated with fire plumes, highlighting the importance of both primary and secondary sources for WSOC in the region. Residual pollution layers enriched with WSOC are observed aloft up to an altitude of 3.2 km and the highest WSOC levels for each flight were typically observed above 500 m. Simultaneous ground WSOC measurements during aircraft overpasses in Pasadena and Riverside typically exhibit lower levels, especially when relative humidity (RH) was higher aloft suggestive of the influence of aerosol-phase water. This points to the underestimation of the radiative effects of WSOC when using only surface measurements. Reduced aerosol-phase water in the eastern desert outflow region likely promotes the re-partitioning of WSOC to the gas phase and suppression of processes to produce these species (partitioning, multiphase chemistry, photolytic production); as a result, WSOC is reduced relative to sulfate (but not as much as nitrate) as aerosol is advected from the Basin to the outflows.

Original languageEnglish (US)
Article numberD00V04
JournalJournal of Geophysical Research: Space Physics
Volume116
Issue number22
DOIs
StatePublished - 2011

Fingerprint

Organic carbon
Aerosols
aerosols
outflow
organic carbon
aerosol
Water
carbon
basin
water
aircraft
San Joaquin Valley (CA)
partitioning
sea breeze
Overpasses
flight
Aircraft
samplers
deserts
airborne survey

ASJC Scopus subject areas

  • Atmospheric Science
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Water-soluble organic aerosol in the Los Angeles Basin and outflow regions : Airborne and ground measurements during the 2010 CalNex field campaign. / Duong, Hanh T.; Sorooshian, Armin; Craven, Jill S.; Hersey, Scott P.; Metcalf, Andrew R.; Zhang, Xiaolu; Weber, Rodney J.; Jonsson, Haflidi; Flagan, Richard C.; Seinfeld, John H.

In: Journal of Geophysical Research: Space Physics, Vol. 116, No. 22, D00V04, 2011.

Research output: Contribution to journalArticle

Duong, Hanh T. ; Sorooshian, Armin ; Craven, Jill S. ; Hersey, Scott P. ; Metcalf, Andrew R. ; Zhang, Xiaolu ; Weber, Rodney J. ; Jonsson, Haflidi ; Flagan, Richard C. ; Seinfeld, John H. / Water-soluble organic aerosol in the Los Angeles Basin and outflow regions : Airborne and ground measurements during the 2010 CalNex field campaign. In: Journal of Geophysical Research: Space Physics. 2011 ; Vol. 116, No. 22.
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