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| Titel |
Bayesian estimation of basal conditions on Rutford Ice Stream, West Antarctica, from surface data |
| VerfasserIn |
Mélanie Raymond Pralong, G. Hilmar Gudmundsson |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250052023
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| Zusammenfassung |
| The determination of basal properties on ice streams from surface data is formulated as a
Bayesian statistical inference problem. The theory is applied to a flow line on Rutford Ice
Stream, West Antarctica. Estimates of bed topography and basal slipperiness are updated
using measurements of surface topography and the horizontal and vertical components of the
surface velocity. The surface topography is allowed to vary within measurement errors.
We calculate the transient evolution of the surface until rates of surface elevation
change are within limits given by measurements. For our final estimation of basal
properties, modelled rates of elevation change are in full agreement with estimates of
surface elevation changes. Results are discarded from a section of the flow line where
the distribution of surface residuals is not consistent with error estimates. Apart
from a general increase in basal slipperiness toward the grounding line, we find no
evidence for any spatial variations in basal slipperiness. In particular, we find that
short-scale variability (< 10h) in surface topography and surface velocities can be
reproduced by the model by variations in basal topography only. Assuming steady-state
conditions, an almost perfect agreement is found between modelled and measured surface
geometry suggesting that the Rutford Ice Stream is currently close to a steady state. |
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