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Calibration of a higher-order 3-D ice flow model of the Morteratsch glacier complex, Engadin, Switzerland

Tijdschriftbijdrage - Tijdschriftartikel

We have reconstructed the ice thickness distribution of the Morteratsch glacier complex, Switzerland, and used this to simulate its flow with a higher-order 3-D model. Ice thickness was measured along transects with a ground-penetrating radar and further extended over the entire glacier using the plastic flow assumption and a distance-weighted interpolation technique. We find a maximum ice thickness of 35052.5m for the central trunk of Vadret da Morteratsch, resulting from a bedrock overdeepening. The average thickness of the glacier complex is 72.218.0 m, which corresponds to a total ice volume of 1.140.28km3. The flow of the glacier is modelled by tuning the rate factor and the sliding parameters taking into account higher-order terms in the force balance. The observed velocities can be reproduced closely (root-mean-square error of 15.0ma-1, R2 = 0.93) by adopting a sliding factor of 1210-16m7N-3 a-1 and a rate factor of 1.610-16 Pa-3 a-1. In this setting, ice deformation accounts for 70% of the surface velocity and basal sliding for the remaining 30%. The modelled velocity field reaches values up to 125ma-1, but also indicates an almost stagnant front and confluence area, which are crucial for understanding the ongoing glacier retreat.
Tijdschrift: Annals of Glaciology
ISSN: 0260-3055
Issue: doi: 10.3189/2013AoG63A434
Volume: 54
Pagina's: 343-351
Jaar van publicatie:2013
Trefwoorden:glaciers, Ice sheet modeling
Toegankelijkheid:Closed