| 5894 |
Creator |
9afccdbe975e25965953e777bb4d6a5f |
| 5894 |
Creator |
ext-afbb4998ef62874592c0951784dedf84 |
| 5894 |
Creator |
ext-1062df500af1967915cd2b1c3624b6c5 |
| 5894 |
Creator |
ext-670621c4b63f42f4a70fce6f42326e2e |
| 5894 |
Creator |
ext-73ae04910933bc249eb34dc8f7e94043 |
| 5894 |
Creator |
ext-a41763d9b645f855edd021741fe4fb2d |
| 5894 |
Date |
2003 |
| 5894 |
Is Part Of |
repository |
| 5894 |
Is Part Of |
p16807324 |
| 5894 |
abstract |
Results from the first chemistry-transport model study of the impact of the 1783–1784
Laki fissure eruption (Iceland: 64°N, 17°W) upon atmospheric composition are presented.
The eruption released an estimated 61 Tg(S) as SO<sub>2</sub> into the troposphere
and lower stratosphere. The model has a high resolution tropopause region, and detailed
sulphur chemistry. The simulated SO<sub>2</sub> plume spreads over much of the Northern
Hemisphere, polewards of ~40°N. About 70% of the SO<sub>2</sub> gas is directly deposited
to the surface before it can be oxidised to sulphuric acid aerosol. The main SO<sub>2</sub>
oxidants, OH and H<sub>2</sub>O<sub>2</sub>, are depleted by up to 40% zonally, and
the lifetime of SO<sub>2</sub> consequently increases. Zonally averaged tropospheric
SO<sub>2</sub> concentrations over the first three months of the eruption exceed 20
ppbv, and sulphuric acid aerosol reaches ~2 ppbv. These compare to modelled pre-industrial/present-day
values of 0.1/0.5 ppbv SO<sub>2</sub> and 0.1/1.0 ppbv sulphate. A total sulphuric
acid aerosol yield of 17–22 Tg(S) is produced. The mean aerosol lifetime is 6–10 days,
and the peak aerosol loading of the atmosphere is 1.4–1.7 Tg(S) (equivalent to 5.9–7.1
Tg of hydrated sulphuric acid aerosol). These compare to modelled pre-industrial/present-day
sulphate burdens of 0.28/0.81 Tg(S), and lifetimes of 6/5 days, respectively. Due
to the relatively short atmospheric residence times of both SO<sub>2</sub> and sulphate,
the aerosol loading approximately mirrors the temporal evolution of emissions associated
with the eruption. The model produces a reasonable simulation of the acid deposition
found in Greenland ice cores. These results appear to be relatively insensitive to
the vertical profile of emissions assumed, although if more of the emissions reached
higher levels (>12 km), this would give longer lifetimes and larger aerosol yields.
Introducing the emissions in episodes generates similar results to using monthly mean
emissions, because the atmospheric lifetimes are similar to the repose periods between
episodes. Most previous estimates of the global aerosol loading associated with Laki
did not use atmospheric models; this study suggests that these earlier estimates have
been generally too large in magnitude, and too long-lived. Environmental effects following
the Laki eruption may have been dominated by the widespread deposition of SO<sub>2</sub>
gas rather than sulphuric acid aerosol. |
| 5894 |
authorList |
authors |
| 5894 |
status |
peerReviewed |
| 5894 |
volume |
3 |
| 5894 |
type |
AcademicArticle |
| 5894 |
type |
Article |
| 5894 |
label |
Stevenson, D.S.; Johnson, C.E.; Highwood, E.J.; Gauci, V. ; Collins, W.J. and Derwent,
R.G. (2003). Atmospheric impact of the 1783-1784 Laki Eruption: Part 1 Chemistry
modelling. Atmospheric Chemistry and Physics, 3 pp. 487–507. |
| 5894 |
label |
Stevenson, D.S.; Johnson, C.E.; Highwood, E.J.; Gauci, V. ; Collins, W.J. and Derwent,
R.G. (2003). Atmospheric impact of the 1783-1784 Laki Eruption: Part 1 Chemistry
modelling. Atmospheric Chemistry and Physics, 3 pp. 487–507. |
| 5894 |
Title |
Atmospheric impact of the 1783-1784 Laki Eruption: Part 1 Chemistry modelling |
| 5894 |
in dataset |
oro |