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Depletion rates of sulfur dioxide in tropospheric volcanic plumes
Author(s) -
Oppenheimer Clive,
Francis Peter,
Stix John
Publication year - 1998
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/98gl01988
Subject(s) - volcano , troposphere , plume , stratosphere , atmospheric sciences , geology , environmental science , volcanic gases , panache , sulfur dioxide , earth science , meteorology , geochemistry , chemistry , geography , inorganic chemistry
The tropospheric sulfur cycle has been closely studied from the standpoint of anthropogenic emissions but less so with respect to volcanic sources. We document here evidence for wide variation in lifetimes of volcanic SO 2 in the troposphere. At one extreme, our observations of the plume associated with the lavadome eruption of Soufriere Hills volcano (Montserrat) suggest loss of gaseous SO 2 at rates exceeding 10 −3 s −1 . While this efficent SO 2 depletion reflects unusual environmental factors, published measurements for Mount Etna's plume approach these rapid rates. In such cases, source strengths of SO 2 must significantly exceed apparent fluxes measured several kilometres downwind. This implies that meteorological and geographic factors, as well as volcanic degassing rates, should be considered in the interpretation of fluxes of SO 2 measured beyond source vents, with ramifications for volcano monitoring and eruption prediction. Furthermore, since most calculations of global volcanic fluxes of sulfur (and other species) to the troposphere are based on extrapolation of SO 2 flux data they may underestimate true source strengths. Finally, we consider that fast sulfur chemistry may also prevail in convecting eruption columns, resulting in partial tropospheric scrubbing of sulfur from stratosphere‐bound plumes.