 |
| Titel |
Chemical processing of volcanic ash within eruption plume and cloud: a numerical modeling approach |
| VerfasserIn |
Gholam Ali Hoshyaripour, Matthias Hort, Baerbel Langmann, Guy Brasseur |
| Konferenz |
EGU General Assembly 2015
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250101672
|
| Publikation (Nr.) |
 EGU/EGU2015-1361.pdf |
|
|
|
|
|
| Zusammenfassung |
| Volcanic ash is recently identified as an active chemical agent in the Earth system. Generated
mainly through lithospheric processes and magma fragmentation, it can pose significant
impacts upon different components of the Earth system for e.g. atmosphere and hydrosphere
on various temporal and spatial scales. While airborne in the atmosphere, transition metals
contained in the ash can catalyze the sulfur oxidation cycle thereby indirectly affecting the
volcanic radiative forcing. Moreover, upon deposition on the surface ocean, ash can release
soluble iron that fertilizes Fe-limited areas of the ocean and stimulate the marine productivity
and CO2 drawdown. Such impacts are provoked through interfacial
processes and thus, are mainly induced by the ash surface composition. Recent studies
suggest that in-plume and in-cloud processing of volcanic ash primarily control its
surface composition. Direct evidences concerning such processes are, however,
lacking.
Here we present the results of our recent investigations on in-plume and in-cloud
processing of volcanic ash. A 1D numerical model is developed that simulates the
gas-ash-aerosol interactions in volcanic eruption plume and cloud at temperatures between
600 C and 0 C focusing on iron, sulfur and halogen chemistry. Results show that sulfuric acid
and water vapor condense at 150 C and 50 C, respectively, generating a liquid coating at the
ash surface that scavenges the surrounding gases (>95extremely acidic (pH |
|
|
|
|
|
|