1783-84 Laki Eruption, Iceland
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1783-84 Laki eruption, Iceland Eruption History and Atmospheric Effects Thor Thordarson Faculty of Earth sciences, University of Iceland 12/8/2017 1 Atmospheric Effects of the 1783-84 Laki Eruption in Iceland Outline . Volcano-Climate interactions - background Laki eruption . Eruption history . Sulfur release and aerosol loading . Plume transport and aerosol dispersal . Environmental and climatic effects 12/8/2017. Concluding Remarks 2 Santorini, 1628 BC Tambora, 1815 Etna, 44 BC Lakagígar, 1783 Toba, 71,000 BP Famous Volcanic Eruptions Krakatau, 1883 Pinatubo, 1991 El Chichón, 1982 Agung, 1963 St. Helens, 1980 Major volcanic eruptions of the past 250 years Volcano Year VEI d.v.i/Emax IVI Lakagígar [Laki craters], Iceland 1783 4 2300 0.19 Unknown (El Chichón?) 1809 0.20 Tambora, Sumbawa, Indonesia 1815 7 3000 0.50 Cosiguina, Nicaragua 1835 5 4000 0.11 Askja, Iceland 1875 5 1000 0.01* Krakatau, Indonesia 1883 6 1000 0.12 Okataina [Tarawera], North Island, NZ 1886 5 800 0.04 Santa Maria, Guatemala 1902 6 600 0.05 Ksudach, Kamchatka, Russia 1907 5 500 0.02 Novarupta [Katmai], Alaska, US 1912 6 500 0.15 Agung, Bali, Indonesia 1963 4 800 0.06 Mt. St. Helens, Washington, US 1980 5 500 0.00 El Chichón, Chiapas, Mexico 1982 5 800 0.06 Mt. Pinatubo, Luzon, Philippines 1991 6 1000 — Volcano – Climate Interactions Key to Volcanic Forcing is: SO2 mass loading, eruption duration plume height replenishment aerosol production, residence time 12/8/2017 5 Volcanic Forcing: sulfur dioxide sulfate aerosols SO2 75%H2SO4+ 25%H2O clear sky 1991 Pinatubo aerosols 12/8/2017 6 More Reflected Less Stratospheric aerosols Solar Flux Upward (Lifetime 1-3 years) IR Flux backscatter dynamic effect absorption Solar Heating emission H2S (near IR) IR H2SO4 SO2 Heating IR Cooling absorption (IR) emission CO 2 forward scatter N2 Enhanced H2O Diffuse Flux Ash Reduced Direct Flux More SO2 H2SO4 Downward Less Total IR Flux Tropospheric aerosols Solar Flux (Lifetime 1-3 weeks) radiative effect 1783-84 Laki Eruption in Iceland (8 June 1783 – 7 February 1784) Second largest flood lava eruption in historical time Iceland’s biggest natural disaster 12/8/2017 8 1783-84 Laki Eruption – What makes it special Lava = 14.7 km3 Tephra = 0.4 km3 SO2 = 100 million tons Very big eruption 12/8/2017 with big impact! 9 Laki Eruption - venue for Big Science Worked on it since 1983 Subject of 6 PhD studies; one more on the way and 1 MSc study 34 refereed journal papers published on different aspects of the eruption! During several of the summer months of the year 1783, when the effect of the sun’s rays to Laki Eruption - venue heatfor the earthBig in theseScience northern regions should have been greatest, there existed a constant fog over all Europe, and great part of North America. This fog was of a permanent nature; it was dry, and the rays of the sun seemed to have little effect towards dissipating it, as they easily do a moist fog, arising from water. They were indeed rendered so faint in passing through it, that when collected in the focus of a burning glass, they would scarce kindle brown paper. Of course, their summer effect in heating the earth was exceedingly diminished. Hence the earth was early frozen, Hence the first snows remained on it unmelted, and received continual additions. Hence the air was more chilled, and the winds more severely cold. Hence perhaps the winter of 1783-4, was more severe, than any that had happened for many years. The cause of this universal fog is not yet ascertained. Whether it was adventitious to this earth, and merely a smoke, proceeding from the consumption by fire of some of those great burning balls or globes which we happen to meet within our rapid course round the sun, and which Benjamin Franklin are sometimes seen to kindle and be destroyed in passing our atmosphere, and whose smoke might (1784) be attracted and retained by our earth; or whether it was the vast quantity of smoke, long continuing to issue during the summer from Hecla in Iceland, and that other volcano which arose out of the sea near that island, which smoke might be spread by various winds, over the northern part of the world, is yet uncertain. PROMOTED The French naturalist M. Mourgue de Montredon was the first to tie the dry fog of 1783 to an eruption in Iceland; He did so in a lecture at the Royal Academy of Montpellier, on 7 August 1783. OTHERS J. L. Christ, German naturalist [1783] Prof. C. G. Kratzenstein, Univ. Copenhagen [1784, B. Franklin. US ambassador in Paris [1784] S. Palsson, Icelandic naturalist [1784] Laki pumice Laki crater Laki NE cone -row Laki - Eruption History 12/8/2017 13 Eruption History I Laki eruption (8 June 1783- 7 February 1784) 12/8/2017 14 explosive; tephra = 0.4 km3 Effusive; lava = 14.7 km3 Laki: Eruption Data Laki fissure The Laki eruption lasted for 8 months, with continuous effusive emissions into the troposphere, as well as 10 El Chichón-size eruptions to a height of 10-13 km, into the lower stratosphere. 12/8/2017 15 Sub-Plinian Explosive Phases High magma discharge & intense fountaining scoria/ash fall Gas-charged subplinian lava eruption columns fountains fountain-fed lava particle-rich gas phase Laki Lining of pumice degassed magma Extremely efficient vent degassing > 70%12/8/2017 of dissolved gas released 16 Laki eruption columns: heights H = 8.2Q1/4 central vent or short12/8/2017 fissure 17 Atmospheric Mass Loading of Sulfur and Other Volatiles 12/8/2017 18 Sulfur Measurements plume column 490 ppm S vents lava 205 ppm S 350 ppm S rising magma 1675 ppm S magma in 12/8/2017 reservoir 19 Laki 15 km 200 Mt sulfuric aerosols 98 Mt SO2 plume column 122 Mt SO2 24 Mt SO2 vents lava rising magma H2O = 235 Mt 139 Mt SO2 Mt (megaton) = 1x109 kg = 1 Tg magma in 12/8/2017 reservoir 20 Sulfur Loadings by Laki-2 12/8/2017 21 Plume and Aerosol Dispersal 12/8/2017 22 Laki Haze: Records of Dispersal Covered the northern quarter of the globe Eyjafjallajökull 2010 Laki Haze: Records of Dispersal Covered the northern quarter of the globe Plume and Aerosol Cloud Transport Aerosol Removal -Tropospheric Dispersal 25 Mt remained climatic effects aloft for >1 year 175 Mt removed, >1000 kg H2SO4 environmental effects per km2 Plumes and aerosols transported within the polar jet stream and dispersed to the surface by subsiding air masses12/8/2017 in high pressure cells 26 ImpactRadiative of Flood Effects Basalt of Eruptions Laki Loading 12/8/2017>200 megatons of sulfate aerosols for 1 year 27 Atmospheric effects: Environmental Impact Science, 19 Nov 2004 12/8/2017 28 Laki and the Haze Famine Environmental Disaster! killed >75% of livestock and >20% of the population at the time Skull from excavation at Búland farm Sulfur and fluorine contaminated ash fall led to the haze famine Environmental Impact Elsewhere The Dry Fog van Swinden 1783 “Now some days before the 24 June (at Franeker thence from the 19th) a certain continuos haze was seen, but this excited no attention, since this phenomenon is not unusual here,….. But on the 24th day of the month the haze, which was stronger than on the preceding day, brought with it a very distinct sulfurous odor. …….many experienced very troublesome headaches and respiratory difficulties, similar to that which they experienced while the atmosphere around us was filled with the vapor of burned sulfur. ….. In the morning of the 25th the fields showed a very sad appearance. The green color of the trees and plants had disappeared and the earth was covered with drooping leaves. One would easily have believed that it was October or November. …… Moreover the injury, and falling of leaves, lasted for some12/8/2017 time.” 30 Laki plumes – Distal Effects 25 Mt 175 Mt Dry Fog • 175 Mt of H2SO4 aerosols removed from the atmosphere in summer and fall of 1783 (Thordarson and Self, 2003) • equivalent to deposition of 1000 kg sulfuric acid per km2 • widespread damage to vegetation and crop in Europe consistent with pollution from acid precipitation • significant increase in mortality in England; up to 25% (Grattan et al., 2003) 12/8/2017 31 Atmospheric Effects: Climatic Impact 12/8/2017 32 Historical Records Summer 1783 • unusual weather • hot July in W-Europe • very intense thunderstorms • cold in North Atlantic, Alaska (?) • snow fall in Poland • cold and rainy in Japan Winter 1783-84 • landmark winter in Europe and E-US • long winter, intense frost • inland seas and straits froze over • ice on Mississippi at New Orleans • moderate in Eurasia and Japan (?) • intense spring floods in Europe 12/8/2017 33 Summer of 1783 UnusuallyThor Thordarson Hot July in 1783 Global Circulation Modelling (Oman et al 2006 (Thordarson and Self 2003) Significant at 90% level Reconstruction from Luterbacher et al. (2004) Anomalies based on 31 yr mean, 1770-1800 Significant at 90% level 12/8/2017 Reconstruction from Luterbacher et al. (2004) 36 Anomalies based on 31 yr mean, 1770-1800 Significant at 90% level 12/8/2017 Reconstruction from Luterbacher et al. (2004) 37 Anomalies based on 31 yr mean, 1770-1800 Temperature Records Europe and Eastern US 1768-98 Temperature record Europe Frequency of zonal weather type in the period 1781-85 T = -1.3oC 12/8/2017 38 50 mb after heating Tropopause Jet stream axis Aerosol cloud North Pole Tropics Aerosol heating decreases Equator-Pole temperature gradient, decreasing height gradient, and makes jet stream (polar vortex) weaker.