Abstract
Abstract. We present steady state (diagnostic) and transient (prognostic) simulations of Midtre Lovénbreen, Svalbard performed with the thermo-mechanically coupled full-Stokes code Elmer. This glacier has an extensive data set of geophysical measurements available spanning several decades, that allow for constraints on model descriptions. Consistent with this data set, we included a simple model accounting for the formation of superimposed ice. Diagnostic results indicated that a dynamic adaptation of the free surface is necessary, to prevent non-physically high velocities in a region of under determined bedrock depths. Observations from ground penetrating radar of the basal thermal state agree very well with model predictions, while the dip angles of isochrones in radar data also match reasonably well with modelled isochrones, despite the numerical deficiencies of estimating ages with a steady state model. Prognostic runs for 53 years, using a constant accumulation/ablation pattern starting from the steady state solution obtained from the configuration of the 1977 DEM show that: 1 the unrealistic velocities in the under determined parts of the DEM quickly damp out; 2 the free surface evolution matches well measured elevation changes; 3 the retreat of the glacier under this scenario continues with the glacier tongue in a projection to 2030 being situated ≈500 m behind the position in 1977.
Highlights
Midtre Lovenbreen (78.53◦ N, 12.04◦ E) is an alpine-type valley glacier in northwest Spitsbergen
A surface digital elevation model (DEM) was created from a digitised form of the Norwegian Polar Institute map (1979) which was constructed from aerial photographs taken in 1977
Using the DEMs of the free surface and the bedrock as inputs to a surface interpolation scheme, the three-dimensional mesh was created by extruding the two-dimensional footprint from the interpolated bedrock to the free surface, producing 10 layers of varying thickness over the whole glacier surface
Summary
Midtre Lovenbreen (78.53◦ N, 12.04◦ E) is an alpine-type valley glacier in northwest Spitsbergen. As with Wadham et al (2006), we use annual surface temperature distribution based on 30 years of measurements made by Det Norske Meteorologiske Institutt at sea level in Ny Alesund. They give a mean annual temperature of −6.0◦C at sea level. Wadham et al (2006) used their flow model to map the temperate region of the glacier by estimating where basal sliding was important in surface velocity measurements along the centre line. We show how the models compare with surface evolution of the data from detailed LiDAR mapping of the 2005 and 2003 surfaces elevation and velocity field (Rees and Arnold, 2007)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
