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OSUG - Terre Univers Environnement

Volcanic plume chemistry in the troposphere : halogens, aerosols and ozone depletion

Séminaire de Tjarda ROBERTS (LPC2E), le mercredi 20 décembre 2017 à 10h, salle 105, OSUG-B

par Sandra Rome - 27 novembre 2017

Titre : "Chimie des panaches volcaniques dans la troposphère : halogènes, aérosols et destruction de l’ozone".

Résumé : Volcanoes release vast amounts of gases and aerosols to the atmosphere. Studies to date have mostly focused on the climate impacts of volcanic SO2 and its oxidation to sulfate particles, and on ash. However, volcanoes emit a number of other gases including volcanic halogens such as HBr and HCl as well as a primary aerosol emission. This emission mixture becomes highly reactive upon entering the atmosphere. The volcanic halogen emissions can be transformed into reactive bromine and chlorine (e.g. BrO, OClO) over very short time-scales (minutes) to cause the depletion of tropospheric ozone downwind from the volcano. Another predicted impact of volcanic plume chemistry is the conversion of inert mercury into a more reactive and easily deposited form. By combining the development of atmospheric box models and in-situ measurements, I seek to characterize this unusual atmospheric chemistry of volcanic plumes, towards making some first assessments of volcanic plume reactive halogen impacts on local, regional, and ultimately global scales.

Par Tjarda Roberts
LPC2E (Laboratoire de physique et chimie de l’environnement et de
l’Espace), Orléans





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