Halogen emissions from a small volcanic eruption: Modeling the peak concentrations, dispersion, and volcanically induced ozone loss in the stratosphere

• Published in: Geophysical Research Letters
• Main Authors: Millard, G, Mather, T, Pyle, D, Rose, W, Thornton, B
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: Hekla; Iceland
• Online Access: https://doi.org/10.1029/2006GL026959; https://ora.ox.ac.uk/objects/uuid:bb67afd3-cbd6-4fce-a081-368d12aeadad

Aircraft measurements in the Hekla, Iceland volcanic plume in February 2000 revealed large quantities of hydrogen halides within the stratosphere correlated to volcanic SO2. Investigation of the longer-term stratospheric impact of these emissions, using the 3D chemical transport model, SLIMCAT suggests that volcanic enhancements of H2O and HNO 3 increased HNO3·3H2O particle availability within the plume. These particles activated volcanic HCl and HBr, enhancing model plume concentrations of ClOx (20 ppb) and BrO x (50 ppt). Model O3 concentrations decreased to near-zero in places, and plume average O3 remained 30% lower after two weeks. Reductions in the model O3 column reduced UV shielding by 15% for 2 days. Plume incorporation into the winter polar vortex after 1 March elevated model vortex Cly and Bry by 0.15 ppb and 7 ppt respectively, and doubled vortex ClOx and BrO. Model results agree quantitatively with the observations made by the DC-8 aircraft. Copyright 2006 by the American Geophysical Union.