Composition and spectral characteristics of ambient aerosol at Mauna Loa Observatory

Journal Article · Tue Mar 19 23:00:00 EST 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/89JD03560· OSTI ID:5469820

Johnson, S A; Kumar, R ^[1]

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1. Argonne National Lab., IL (USA)

Ambient aerosol particles were sampled continuously with a time resolution of {approximately}4 hours for a period of 8 days at the Mauna Loa Observatory, Hawaii, in August 1986. The samples were analyzed on-site for their chemical composition by attenuated total internal reflection infrared spectroscopy. The infrared absorption spectra of the samples also provided data on aerosol light absorbance characteristics at 9.1 and 10.6 {mu}m - wavelengths of interest in determining aerosol backscatter coefficients for CO{sub 2} lidars. The chemical species in the ambient aerosol varied considerably during this 8-day period. The aerosol was acidic ((NH{sub 4}){sub 3}H(SO{sub 4}){sub 2},NH{sub 4}HSO{sub 4}, or H{sub 2}SO{sub 4}) rather than neutral ((NH{sub 4}){sub 2}SO{sub 4}) for a major fraction of the sampling time. The samples generally showed much higher absorbance at 9.1 {mu}m than at 10.6 {mu}m. Changes in the chemical composition between (NH{sub 4}){sub 2}SO{sub 4} and the more acidic forms were accompanied by substantial changes in the sample's absorbance at 9.1 {mu}m but lesser changes in the absorbance at 10.6 {mu}m. These variations could have a profound effect on backscatter coefficients of atmospheric aerosol particles at CO{sub 2} wavelengths.

• OSTI ID: 5469820
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 96:D3; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
ABSORPTION
ABSORPTION SPECTROSCOPY
AEROSOLS
AIR POLLUTION
AMMONIUM COMPOUNDS
AMMONIUM SULFATES
BACKSCATTERING
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL COMPOSITION
COLLOIDS
DEVELOPED COUNTRIES
DISPERSIONS
ELECTROMAGNETIC RADIATION
FEDERAL REGION IX
HAWAII
HYDROGEN COMPOUNDS
INFRARED RADIATION
INORGANIC ACIDS
MEASURING INSTRUMENTS
NORTH AMERICA
OPTICAL RADAR
OXIDES
OXYGEN COMPOUNDS
PARTICLES
PARTICULATES
POLLUTION
RADAR
RADIATIONS
RANGE FINDERS
SAMPLING
SCATTERING
SOLS
SPECTRAL RESPONSE
SPECTROSCOPY
SULFATES
SULFUR COMPOUNDS
SULFURIC ACID
USA