title: Bromine monoxide in volcanic plumes - A global survey of volcanic plume composition and chemistry derived from Sentinel-5 Precursor/TROPOMI data
creator: Warnach, Simon
subject: ddc-530
subject: 530 Physics
subject: ddc-550
subject: 550 Earth sciences
description: Bromine monoxide (BrO) is a radical which influences chemical processes in the atmosphere, in particular the abundance of ozone. Furthermore, the molar bromine to sulphur ratio in volcanic gas emissions is a proxy for the magmatic composition of a volcano and potentially an eruption forecast parameter.  In this thesis, the distribution of SO2, BrO and the BrO/SO2 ratio in volcanic gas plumes is surveyed globally over a four-year period (2018 - 2021) using Differential Optical Absorption Spectroscopy (DOAS) and spectral data of the S-5P/TROPOMI satellite instrument. TROPOMI's high spatial resolution (up to 3.5x5.5 km^2) and its daily global coverage yield BrO/SO2 ratios even for minor eruptions and quiescent degassing. Plumes are automatically detected globally through a plume detection algorithm, leading to a total of 4323 volcanic plumes and a detection of BrO in 1449 of them. 3063 volcanic plumes can be clearly assigned to 43 volcanoes, for which subsequently the mean BrO/SO2 ratio is calculated - increasing the global data-base of reported BrO/SO2 ratios from 28 to 60 volcanoes. For the first time, BrO/SO2 ratios were successfully determined for pure hot spot volcanoes - all of which yield low BrO/SO2 ratios of 5x 10^-5, in contrast to 2-16x 10^-5 for arc volcanoes. The observed BrO/SO2 ratios were in good agreement with ground-based measurements.  A spatial gradient of decreasing BrO/SO2 ratio towards the plume's center within major volcanic plumes could be attributed to O3 destruction in the plume's center both from a conceptual model and an empirical plume model. The decrease in the BrO/SO2 towards the center was observed over 1000 km, indicating the strong chemical impact of reactive volcanic halogenes in the atmosphere.
date: 2022
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/31910/1/Thesis_Druckversion.pdf
identifier: DOI:10.11588/heidok.00031910
identifier: urn:nbn:de:bsz:16-heidok-319109
identifier:   Warnach, Simon  (2022) Bromine monoxide in volcanic plumes - A global survey of volcanic plume composition and chemistry derived from Sentinel-5 Precursor/TROPOMI data.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/31910/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng