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| Titel |
The impact of the 1783–1784 AD Laki eruption on global aerosol formation processes and cloud condensation nuclei |
| VerfasserIn |
A. Schmidt, K. S. Carslaw, G. W. Mann, M. Wilson, T. J. Breider, S. J. Pickering, T. Thordarson  |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 13 ; Nr. 10, no. 13 (2010-07-05), S.6025-6041 |
| Datensatznummer |
250008600
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| Publikation (Nr.) |
 copernicus.org/acp-10-6025-2010.pdf |
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| Zusammenfassung |
| The 1783–1784 AD Laki flood lava eruption commenced on 8 June 1783 and
released 122 Tg of sulphur dioxide gas over the course of 8 months
into the upper troposphere and lower stratosphere above
Iceland. Previous studies have examined the impact of the Laki
eruption on sulphate aerosol and climate using general circulation
models. Here, we study the impact on aerosol microphysical processes,
including the nucleation of new particles and their growth to cloud
condensation nuclei (CCN) using a comprehensive Global Model of
Aerosol Processes (GLOMAP). Total particle concentrations in the free
troposphere increase by a factor ~16 over large parts of the
Northern Hemisphere in the 3 months following the onset of the
eruption. Particle concentrations in the boundary layer increase by
a factor 2 to 5 in regions as far away as North America, the Middle
East and Asia due to long-range transport of nucleated particles. CCN
concentrations (at 0.22% supersaturation) increase by a factor 65 in
the upper troposphere with maximum changes in 3-month zonal mean
concentrations of ~1400 cm−3 at high northern
latitudes. 3-month zonal mean CCN concentrations in the boundary layer
at the latitude of the eruption increase by up to a factor 26, and
averaged over the Northern Hemisphere, the eruption caused a factor 4
increase in CCN concentrations at low-level cloud altitude. The
simulations show that the Laki eruption would have completely
dominated as a source of CCN in the pre-industrial atmosphere. The
model also suggests an impact of the eruption in the Southern
Hemisphere, where CCN concentrations are increased by up to a factor
1.4 at 20° S. Our model simulations suggest that the impact
of an equivalent wintertime eruption on upper tropospheric CCN
concentrations is only about one-third of that of a summertime
eruption. The simulations show that the microphysical processes
leading to the growth of particles to CCN sizes are fundamentally
different after an eruption when compared to the unperturbed
atmosphere, underlining the importance of using a fully coupled
microphysics model when studying long-lasting, high-latitude
eruptions. |
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