Abstract
For improving the numerical modelling of volcanic ash atmospheric concentration by addressing
volcanic ash aggregation processes and removal by wet deposition during long-range transport, an
interdisciplinary approach by combining volcanic, meteorological, atmospheric and climate research
is wishful. The application of the coupled on-line atmosphere-ash model REMOTE (Langmann et al.,
2008; Langmann et al., 2010) is well beyond the current modelling strategy for volcanic ash dispersion
and deposition as it offers the possibility to study feedback mechanisms between trace species and
climate (Langmann, 2007). REMOTE explicitly determines cloud processes at every model time step
so that e.g. ice formation on volcanic ash can directly alter precipitation formation. It is planned to
use REMOTE to develop suitable algorithms for volcanic ash aggregation and wet deposition during
long-range transport to be used in standard off-line volcanic ash forecast models. Neglecting volcanic
ash aggregation mechanisms may lead to model results, which underestimate fine volcanic ash fallout
and overestimate airborne ash concentrations during long-range transport.
