February 28, 2007
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A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999
FROM VOLUME 5, NUMBER 2, FEBRUARY 1992
CLOUDS AND THE SULFUR CYCLE
"Seasonal Variations of Dimethylsulfide Emissions and Atmospheric
Sulfur and Nitrogen Species over the Western North Atlantic Ocean," H.
Berresheim (Atmos. Sci., Georgia Inst. Technol., Atlanta GA 30332), M.O. Andreae
et al., Tellus, 43B(5), 353-372, Nov. 1991
Measurements of atmospheric DMS, SO2, aerosol methanesulfonate (MSA),
nss-SO42-, NH4+, NO3- and other major ions were made over an entire year. DMS
was also measured in surface seawater, and dimethylsulfoxide and other trace
compounds measured in rainwater samples. The annual DMS flux, highest in fall,
is negligible compared to the sulfur from North America during westerly winds,
but may dominate the sulfur budget in easterly winds. The yield of MSA from DMS
oxidation may be similar in both air masses. Aerosol particles were mainly
acidic with NH4+/nss-SO42- ratios of 1-2 mol/mol.
"Measurements of Aitken Nuclei and Cloud Condensation Nuclei in the
Marine Atmosphere and Their Relation to the DMS-Cloud-Climate Hypothesis,"
D.A. Hegg (Dept. Atmos. Sci., Univ. Washington, AK-40, Seattle WA 98195), L.F.
Radke, P.V. Hobbs, J. Geophys. Res., 96(D10), 18,727-18,733,
Oct. 20, 1991.
New airborne measurements provide quantitative support for some facets of
the DMS-cloud-climate hypothesis. They suggest that layers of high
concentrations of Aitken nuclei near the tops of marine clouds are due to
photochemical nucleation, and show a significant correlation between cloud
condensation nuclei in the boundary layer and mean cloud droplet concentration
in stratus clouds topping a marine boundary layer.
"Seasonal Relationship Between Cloud Condensation Nuclei and Aerosol
Methanesulfonate in Marine Air," G.P. Ayers (Div. Atmos. Res., CSIRO, Priv.
Bag 1, Mordialloc 3195, Australia), J.L. Gras, Nature, 353(6347),
834-835, Oct. 31, 1991.
In an attempt to evaluate the link between DMS and cloud condensation nuclei
(CCN) implied by the DMS-cloud-climate hypothesis, nine years of data are
presented which show a seasonal relationship between CCN and methanesulfonate,
an easily sampled oxidation product of DMS. Results confirm that DMS emissions
strongly influence CCN concentrations, but at low concentrations of
methanesulfonate, there may be a different source of CCN.
"Sulfur Isotope Measurements of Submicrometer Sulfate Aerosol
Particles over the Pacific Ocean," J.A. Calhoun (Lab. Glac. & Geophys.
de l'Environ., BP 96, 38402 St.-Martin-d'Heres Cedex, France), T.S. Bates, R.J.
Charlson, Geophys. Res. Lett., 18(10), 1877-1880, Oct. 1991.
Measurements of stable sulfur isotopes in submicrometer aerosol particles
from the South Pacific were used to test the hypothesis that the primary source
of atmospheric nss-SO42- is marine emissions of DMS. The observed isotopic
fractionation between seawater SO42- and nss-SO42- supports this hypothesis.
"A Global Three-Dimensional Model of the Tropospheric Sulfur Cycle,"
J. Langner (Dept. Meteor., Stockholm Univ., S-106 91 Stockholm, Swed.), H.
Rodhe, J. Atmos. Chem., 13(3), 225-263, Oct. 1991.
The model treats the emission, transport, chemistry and removal processes of
DMS, SO2 and SO42-. Oxidation of DMS by OH radicals together with a global
emission of 16 Tg DMS-S yr-1 from the oceans yields marine boundary layer DMS
concentrations consistent with observations.
"Continuous Determination of Dimethylsulfide at Part-per-Trillion
Concentrations in Air by Atmospheric Pressure Chemical Ionization Mass
Spectrometry," T.J. Kelly (Battelle, 505 King Ave., Columbus OH 43201),
D.V. Kenny, Atmos. Environ., 25A(10), 2155-2160, 1991.
"Determination of Aqueous Dimethyl Sulfide Using Isotope Dilution Gas
Chromatography/Mass Spectrometry," R.G. Ridgeway Jr., A.R. Bandy (Dept.
Chem., Drexel Univ., Philadelphia PA 19104), D.C. Thornton, Marine Chem.,
33, 321-334, 1991. Describes this new purge and trap method and
measurements using it in the northeastern North Atlantic Ocean in spring.
"Measurements of Atmospheric Dimethyl Sulfide and Carbon Disulfide in
the Western Atlantic Boundary Layer," D.J. Cooper (Sch. Marine/Atmos. Sci.,
Univ. Miami, 4600 Rickenbacker Causeway, Miami FL 33149), E.S. Saltzman, ibid.,
153-168. The magnitude of diurnal variations found in shipboard measurements
appears to be controlled by local meteorology, although rapid daytime oxidation
is suggested in some cases.
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