Atmospheric Chemistry and Physics Atmospheric impact of the 1783–1784 Laki eruption: Part I Chemistry modelling

• Main Authors: D. S. Stevenson, C. E. Johnson, E. J. Highwood, V. Gauci, W. J. Collins, R. G. Derwent
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2003
• Subjects: Laki; Iceland
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.405.567; http://hal.archives-ouvertes.fr/docs/00/29/52/55/PDF/acp-3-487-2003.pdf

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 SO2 into the troposphere and lower stratosphere. The model has a high resolution tropopause region, and detailed sulphur chemistry. The simulated SO2 plume spreads over much of the Northern Hemisphere, polewards of ∼40 ◦ N. About 70% of the SO2 gas is directly deposited to the surface before it can be oxidised to sulphuric acid aerosol. The main SO2 oxidants, OH and H2O2, are depleted by up to 40 % zonally, and the lifetime of SO2 consequently increases. Zonally averaged tropospheric SO2 concentrations over the first three months of the eruption exceed 20 ppbv, and sulphuric acid aerosol reaches ∼2 ppbv. These compare to modelled preindustrial/present-day