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| Titel |
Validation of a novel 2D glacier drainage system model with Gornergletscher's seasonal evolution and lake outbursts |
| VerfasserIn |
M. A. Werder, I. J. Hewitt, C. Schoof, M. Huss, G. E. Flowers |
| 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 |
250070674
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| Zusammenfassung |
| We apply a novel glacier drainage system model to Gornergletscher,
Switzerland. This two dimensional model combines distributed and
channelised drainage at the bed coupled to an englacial storage and
routing component. Notably the channel locations are not fixed but
rather evolve as part of the model solution.
Here we present results of a model validation study using the
extensive data set collected on Gornergletscher in 2004-2008. We
force the model with meltwater and precipitation input derived from an
energy balance model (25m spatial and 1h temporal resolution) which is
fed to the subglacial drainage system via moulins at mapped locations.
The model is tuned to the proglacial hydrograph and is validated by
comparing: (i) modelled subglacial water pressure to measured water
pressures in boreholes, (ii) subglacial water sheet thickness to
uplift measured at GPS stations and (iii) modelled and measured tracer
breakthrough times. Further, we use the yearly occurring lake
outburst floods to test the model in a highly dynamic setting. In
particular we look at the influence of the existing drainage system on
the outburst and vice versa, water storage/release processes and the
transformation of the lake outflow hydrograph into the proglacial
hydrograph.
The model reproduces many of the features observed at Gornergletscher
and elsewhere: seasonal evolution of the basal drainage system through
the formation of an arborescent network of subglacial channels, delay
between daily melt water input and proglacial discharge, large en- and
subglacial storage during lake outbursts and transformation of the
outburst hydrographs. |
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