Large Variations in Volcanic Aerosol Forcing Efficiency Due to Eruption Source Parameters and Rapid Adjustments
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Publication Date
2020-10-16Journal Title
Geophysical Research Letters
ISSN
0094-8276
Publisher
American Geophysical Union (AGU)
Volume
47
Issue
19
Type
Article
This Version
AM
Metadata
Show full item recordCitation
Marshall, L., Smith, C., Forster, P., Aubry, T., Andrews, T., & Schmidt, A. (2020). Large Variations in Volcanic Aerosol Forcing Efficiency Due to Eruption Source Parameters and Rapid Adjustments. Geophysical Research Letters, 47 (19) https://doi.org/10.1029/2020GL090241
Abstract
The relationship between volcanic stratospheric aerosol optical depth (SAOD) and volcanic radiative forcing is key to quantify volcanic climate impacts. In their fifth assessment report, the Intergovernmental Panel on Climate Change used one scaling factor between volcanic SAOD and volcanic forcing based on climate model simulations of the 1991 Mt. Pinatubo eruption, which may not be appropriate for all eruptions. Using a large-ensemble of aerosol-chemistry-climate simulations of eruptions with different sulfur dioxide emissions, latitudes, emission altitudes and seasons, we find that the effective radiative forcing (ERF) is on average 20% less than the instantaneous radiative forcing, predominantly due to a positive shortwave cloud adjustment. In our model, the volcanic SAOD-ERF relationship is non-unique and varies widely depending on time since an eruption, eruption latitude and season due to differences in aerosol dispersion and incoming solar radiation. Our revised SAOD-ERF relationships suggest that volcanic forcing has been previously overestimated.
Sponsorship
Natural Environment Research Council (NE/S000887/1)
Natural Environment Research Council (NE/N006038/1)
Royal Society (NIF\R1\180809)
Identifiers
External DOI: https://doi.org/10.1029/2020GL090241
This record's URL: https://www.repository.cam.ac.uk/handle/1810/310202
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