Volcanic
ash modeling with the online NMMB/BSC-ASH-v1.0 model
Alex
Marti
Barcelona Supercomputing Center
Noon Dec 15 in Room 2155
Abstract:
Large explosive volcanic eruptions can inject significant amounts of
tephra (ash) and aerosols (e.g. SO2) into the atmosphere inducing a
multi-scale array of physical, chemical and biological feedbacks
within the environment. Volcanic Ash Transport and Dispersal (VATD)
models are used to simulate the atmospheric transport, dispersion and
ground deposition in order to generate operational short-term
forecasts that support civil aviation and emergency management. In
addition, other model applications include reconstruction of past
events, probabilistic hazard assessments or simulation of recent
eruptions for model evaluation purposes. In all cases, the modeling
system involves a driving Numerical Weather Prediction (NWP) model or a
meteorological reanalysis dataset, an emission or source model for the
eruption column (volcanic plume) and the VATD. Traditionally, VATDs
have evolved decoupled (offline) from NWPs. Although this common
approach has advantages from the operational point of view, it can lead
to inaccurate handling of atmospheric processes with time scales
smaller than the NWP output frequency and neglects eventual feedback
effects of the volcanic pollutants on local-scale meteorology. The
aim of this talk is to present and describe the NMMB/BSC-ASH, a new
on-line model to simulate the emission, transport and deposition of
tephra particles released from volcanic eruptions. The model builds on
the NMMB/BSC Chemical Transport Model (NMMB/BSC-CTM), which we have
modified to account for the specifics of volcanic particles. The final
objective in developing the NMMB/BSC-ASH model is two-fold. On one
hand, at a research level, we aim at studying the differences between
the online/offline approaches and the role of feedback effects of dense
volcanic ash clouds on the radiative budget and regional meteorology.
On the other hand, at an operational level, the low computational cost
of the NMMB dynamic core suggests that NMMB/BSC-ASH could be applied
in a future for more accurate online operational forecasting of
volcanic ash clouds.