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| Titel |
Snow entrainment in applied avalanche modeling using SamosAT |
| VerfasserIn |
J.-T. Fischer, M. Granig, P. Jörg |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250070116
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| Zusammenfassung |
| SamosAT is a simulation toolbox for avalanches. It includes a model for dense flow
avalanches which describes an avalanche as a shallow flow and can be used with various
rheologies. Additionally a two phase air/ice particle mixture model is used to describe the
motion of powder snow avalanches. The fundamental laws of mass and momentum
conservation are the basis of the dynamic models.
The initial mass distribution is one of the main input variables when considering avalanche
simulations. Release areas and release heights are defined with certain rules found in
literature. Snow entrainment and erosion along the avalanche path are important
processes influencing the avalanche dynamics. When taking entrainment processes into
account, the model equations of mass and momentum balance gain extra terms
and parameters. Additionally entrainment areas and heights have to be defined.
To this date the implementation of these processes in applied avalanche models
is still work in progress. The two model types of SamosAT incorporate different
entrainment possibilities. For the dense flow model, frontal entrainment (ploughing) or a
shear stress dependent erosion can be considered. The mass of the powder snow
avalanche is determined by a shear stress dependent flux function. Here the mass can
be entrained from the underlying dense flow avalanche or directly from the snow
cover.
In this work the implementation of the different entrainment mechanisms in SamosAT is
described. Furthermore a new ’mountain snow cover approach’ is suggested in order to
provide a standardized method to determine the initial mass distribution when considering
significant amounts of entrainable snow. This approach is based on the well known methods
used to determine release heights in applied avalanche modeling. Finally well documented
avalanche events are compared to the simulation results considering the different snow
entrainment mechanisms. |
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