Summary: Isotopic constraints on non-photochemical sulfate production in the
Arctic winter
Justin R. McCabe,1
Joel Savarino,2
Becky Alexander,3
Sunling Gong,4
and Mark H. Thiemens1
Received 15 November 2005; revised 6 January 2006; accepted 2 February 2006; published 9 March 2006.
[1] The oxygen isotopic composition (D17
O) of non-
seasalt sulfate (NSS) aerosol was measured in samples from
Alert, Canada over one year (July 1999­June 2000) and
used to quantify the S(IV) oxidants. Measurements of D17
O
in NSS are used to evaluate the relative contributions of O3,
H2O2, and OH oxidation leading to the formation of SO4
2À
compared to a model of Feichter et al. (1996). The isotopic
values suggest that there is a twofold overestimate of ozone
oxidation in the model during winter. The isotopic

Source: Alexander, Becky - Department of Atmospheric Sciences, University of Washington at Seattle

Collections: Environmental Sciences and Ecology; Geosciences