Publication Date:
2021-01-19
Description:
High precision and accuracy in volcanic SO2 emission rate quantification is critical for
eruption forecasting and, in combination with in-plume gas ratios, quantifying global
volcanic emission inventories. Light dilution, where scattering of ultraviolet light dilutes
plume SO2 absorbance signals, has been recognized for more than 50 years, but is still not
routinely corrected for during gas flux quantification. Here we use modeling and empirical
observations from Masaya volcano, Nicaragua, to show that light dilution produces: i)
underestimates in SO2 that can reach a factor of 5 and, at low column densities, cause little
impact on standard retrieval fit quality, even for heavily diluted spectra; ii) retrieved SO2
amounts that are capped by a maximum value regardless of the true amount of SO2, with
this maximum amount being reduced as light dilution increases. Global volcanic volatile
emission rates may therefore be significantly underestimated. An easily implementable
dual-waveband analysis provides a means to detect, and in clear sky conditions, correct
dilution effects directly from the spectra, opening a path to more accurate SO2
quantifications.
Description:
Published
Description:
528753
Description:
5V. Processi eruttivi e post-eruttivi
Description:
JCR Journal
Keywords:
04.08. Volcanology
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
Permalink