Publikationsdatum:
2019-12-03
Beschreibung:
Aerosol particle number concentrations have been measured at Halley and Neumayer on the
Antarctic coast, since 2004 and 1984, respectively. Sulphur compounds known to be implicated in particle
formation and growth were independently measured: sulphate ions and methane sulphonic acid in
filtered aerosol samples and gas phase dimethyl sulphide for limited periods. Iodine oxide, IO, was
determined by a satellite sensor from 2003 to 2009 and by different ground-based sensors at Halley in
2004 and 2007. Previous model results and midlatitude observations show that iodine compounds
consistent with the large values of IO observed may be responsible for an increase in number concentrations
of small particles. Coastal Antarctica is useful for investigating correlations between particles, sulphur, and
iodine compounds, because of their large annual cycles and the source of iodine compounds in sea ice. After
smoothing all the measured data by several days, the shapes of the annual cycles in particle concentration
at Halley and Neumayer are approximated by linear combinations of the shapes of sulphur compounds
and IO but not by sulphur compounds alone. However, there is no short-term correlation between IO and
particle concentration. The apparent correlation by eye after smoothing but not in the short term suggests
that iodine compounds and particles are sourced some distance offshore. This suggests that new particles
formed from iodine compounds are viable, i.e., they can last long enough to grow to the larger particles that
contribute to cloud condensation nuclei, rather than being simply collected by existing particles. If so, there is
significant potential for climate feedback near the sea ice zone via the aerosol indirect effect.
Repository-Name:
EPIC Alfred Wegener Institut
Materialart:
Article
,
isiRev
Format:
application/pdf
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