-
Schellenberger, Thomas; Dunse, Thorben; Kääb, Andreas; Schuler, Thomas; Hagen, Jon Ove Methlie & Reijmer, Carleen
(2017).
Multi-year surface velocities and sea-level rise contribution of the Basin-3 and Basin-2 surges, Austfonna, Svalbard.
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Winsvold, Solveig Havstad; Kääb, Andreas; Andreassen, Liss Marie & Hagen, Jon Ove Methlie
(2016).
Investigating glaciers using time-series of remote sensing data.
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Lefeuvre, Pierre-Marie; Jackson, Miriam; Zwinger, Thomas; Lappegard, Gaute; Hagen, Jon Ove Methlie & Gagliardini, Olivier
(2016).
Subglacial Processes and Hydrology.
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Schellenberger, Thomas; Dunse, Thorben; Kääb, Andreas; Schuler, Thomas; Hagen, Jon Ove Methlie & Reijmer, Carleen
(2016).
The surge must go on: extended surface velocity time series and frontal ablation estimates of Basin-3 (and Basin-2), NE-Svalbard.
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Lefeuvre, Pierre-Marie; Zwinger, Thomas; Messerli, Alexandra; Jackson, Miriam; Lappegard, Gaute & Hagen, Jon Ove Methlie
(2015).
Direct monitoring of the subglacial system: how does it differ from borehole measurements?
Show summary
Measurements of pressure at the glacier bed are made from sensors installed either directly at the glacier bed (load cells) or in boreholes. Results from both kinds of instrumentation show a seasonal evolution of the subglacial drainage system. However, the characteristics of the response of each to surface melting and rainfall are significantly different. This study summarizes results from time series analysis of basal pressure and modelling work conducted at the Svartisen Subglacial Laboratory in order to compare the outcome with the understanding of the subglacial system from borehole campaigns. Installed under 200 m of glacier ice, the load cell network shows periods with spatial anti-correlation in summer, which is caused by stress redistribution between the efficient drainage system and isolated parts of the glacier bed. A full stress ice flow model reveals the importance of this mechanical stress transfer around subglacial channels that is responsible for causing daily pressure events at the glacier bed during stable weather. A characteristic event recorded at a load cell is a sudden drop-and-peak in pressure, usually corresponding with the peak in subglacial water pressure. These typical events are not observed in borehole measurements, they instead measure sinusoidal fluctuations in water pressure. Different response characteristics are also observed during spring speed-up events. During these events, pressure sensors in boreholes generally become connected to an efficient drainage system and then exhibit daily pressure fluctuations for the rest of the melt season. Instead of presenting an increase in connection and activity, the load cells show a damped response after the subglacial drainage system has accommodated the first input of meltwater. The observations from load cells and boreholes are not contradictory, instead they complement each other and help characterize the mechanical and hydrological dynamics occurring at the glacier bed.
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Lefeuvre, Pierre-Marie; Zwinger, Thomas; Jackson, Miriam; Lappegard, Gaute & Hagen, Jon Ove Methlie
(2015).
Characterisation and Cause of Subglacial Perturbations Directly Measured at the Glacier bed.
Show summary
Direct measurements of pressure at the glacier bed are crucial in understanding temporal variation in basal friction and its effect on sliding. We investigate a 20-year pressure record from sensors installed at the ice-rock interface (under 200 m of glacier ice) part of the instrumentation at the Svartisen Subglacial Laboratory. We characterise a regularly occurring subglacial perturbations called “pressure events” in order to identify the involved mechanisms. These events are assumed to depend on the intensity of the glacier response to surface melting and changes in the capacity of the drainage system. They occur on a daily basis during periods of stable weather in the summer and show a drop in pressure followed by a pressure peak and a slow decline until pressure returns to local overburden pressure. Pressurisation of the hydrological system triggers the observed drop in pressure, although the exact process that causes this change locally remains uncertain. The pressure peak and subsequent exponential decay, however, are well understood and due to stress redistribution at the glacier bed. The presence of channels and cavities at the glacier bed transfers the load to areas where the ice rests directly on bedrock, which significantly increases pressure and friction. After the peak, the shape of the decrease in pressure is dependent on ice flow and the form of the contraction of nearby channels and cavities. Sometimes, pressure events do not show the contraction of the hydrological system and we demonstrate that stress redistribution between a pressurised channel and a hydrologically isolated part of the bed can also explain this feature based on a full Stokes model.
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Dunse, Thorben; Schellenberger, Thomas; Hagen, Jon Ove Methlie; Kääb, Andreas; Schuler, Thomas & Reijmer, Carleen
(2015).
A surge of the Austfonna ice cap, Svalbard, promoted by a hydro-thermodynamic feedback to summer melt.
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Lefeuvre, Pierre-Marie; Jackson, Miriam; Lappegard, Gaute & Hagen, Jon Ove Methlie
(2014).
Effect of diurnal surface melt and capacity of the subglacial drainage system on glacier bed perturbations.
Show summary
We investigate the relationship between glacier bed response and successions of days
with melt driven diurnal discharge as an attempt to qu
antify the temporal evolution of the
capacity of the subglacial drainage system, or in other words its history.
The study focuses on successive diurnal discharge that identifies when the drainage
capacity is greater than/or in balance with surface melt i
nput. We quantify how the bed
responds during these periods based on a 20 year record of direct observations of basal
pressure from the Svartisen Subglacial Laboratory (under ~200m thick ice). Results show
an intermittent connection between series of daily
discharge and daily pressure events.
The bed response is maximal at first, but the diurnal signal dampens non
-
linearly over the
next days to finally reach local ice overburden pressure. Decrease in pressure events
amplitude is assumed to indicate a reduct
ion of the area affected by pressurised channels
through load transfer mechanisms. A full Stokes model with simple mesh geometry
reproduces these basic amplitude variations.
Our observations contrasts with the perception from surface boreholes that subgl
acial
water pressure can vary from atmospheric to ice overburden on diurnal time scale. We
discuss the differences.
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Lefeuvre, Pierre-Marie; Jackson, Miriam; Lappegard, Gaute & Hagen, Jon Ove Methlie
(2014).
Two summers with contrasting spatial variability in glacier basal pressure.
Show summary
At the Svartisen
Subglacial Laboratory, load cells installed at the ice rock interface under
~200 m of glacier ice have been recording basal pressure for 20 years. Synchronous
pressure variations between load cells are investigated as evidence of hydrological bed
connectiv
ity and stress redistribution.
A running Pearson correlation is used to gain insights into the temporal variation in
response within a sensor array. By studying the nature of this correlation as well as the
correlation between sensor pairs, it is possibl
e to investigate evolution of the degree of
synchronous response and to some extent basal connectivity at the glacier bed.
Persistent seasonal variations associated with the melt season are observed over the entire
measurement period, indicating dependenc
e on surface hydrological forcing. Overlying
this trend, particular years with longer periods of positive and negative correlation are
presented to show contrasting inter
-
annual variability in basal pressure. Stable weather
appears to enhance connectivity
of the sensors, which may be attributed to the
development of a persistent drainage system. An anti
-
correlated connectivity is associated with an increase in the rate of daily subglacial discharge measured nearby, and may be related to channel migration or cavity opening at the glacier bed.
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Lefeuvre, Pierre-Marie; Jackson, Miriam; Lappegard, Gaute & Hagen, Jon Ove Methlie
(2014).
Statistical study of the subglacial connectivity as revealed by pressure records.
Show summary
At the Svartisen Subglacial Laboratory, pressure cells installed at the ice–rock interface under ~200 m of glacier ice have been recording basal pressure for 20 years. Four sensors in particular are studied, two pairs of sensors located 0.45 and 1 m apart that generally show correlation within the pair in the sensor response to changes in the subglacial hydrology. By studying the nature of this correlation as well as the correlation (or anti-correlation) between sensors in different pairs, it is possible to investigate evolution of the degree of connectivity of the hydrological system at the glacier bed. We compare the response of the first pair of sensors installed on an exposed gentle bump to a second pair, which are installed at the base and top (facing down) of an overhanging cliff. The sensitivity of the exposed pair is more pronounced than the latter, indicating the importance of their location and giving us vital information on the extent of the area affected by these events. A statistical overview of the nature of the response shows that certain signals are seen repeatedly in the load cell records and reflect the importance of the different kinds of perturbations in the hydrological system. It is also a firm confirmation that the connectivity of the subglacial hydrological system is highly dependent on the season, with the connectivity showing a monotonic increase in connectivity from early spring to early autumn (September). Significant changes in connectivity appear to be triggered by an increase in the rate of subglacial discharge measured nearby, and may be related to cavity opening at the glacier bed.
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Lefeuvre, Pierre-Marie; Jackson, Miriam; Lappegard, Gaute; Hagen, Jon Ove Methlie & Engelhardt, Markus
(2014).
The Glacier Bed. Does it know it's raining?
Show summary
At the Svartisen Subglacial Laboratory, pressure cells installed at the ice rock interface under ~200 m of glacier ice have been recording basal pressure for 20 years. Five sensors in particular are studied, covering a 22m zone, that generally show correlation in the sensor response to changes in the subglacial hydrology. By studying the nature of this correlation as well as the correlation (or anti correlation) between sensors, it is possible to investigate the evolution of the degree of connectivity at the glacier bed. Significant changes in connectivity on an annual basis are reported and its potential impact on glacier flow is discussed.
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Nuth, Christopher; Kohler, Jack & Hagen, Jon Ove Methlie
(2014).
On the Dynamics of Kronebreen and Kongsvegen.
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Dunse, Thorben; Schuler, Thomas & Hagen, Jon Ove Methlie
(2014).
Interaction of Svalbard glaciers and the ecosystem of the Barents Sea.
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Lefeuvre, Pierre-Marie; Jackson, Miriam; Lappegard, Gaute & Hagen, Jon Ove Methlie
(2013).
Delay in Basal Pressure Response Caused by Changes in Bed Conditions.
Show summary
At the Svartisen Subglacial Laboratory, pressure cells have been recording basal pressure discontinuously for 20 years. Two pairs of sensors installed in bedrock under ~200m of ice located 0.45 and 1 meter apart offer the possibility to investigate time delay of pressure variation between sensors. Based on a wavelet transform analysis, we suggest that this delay is not constant in time, but its distribution characterises a particular group of pressure events. We compare the results for the first pair of sensor installed on an exposed gentle bump to the second, which is placed at the base and top (facing down) of an overhanging cliff. The sensitivity of the former is much more pronounced than the latter stressing the importance of their location and the globality of the detected events. The latter appears to be triggered by increasing rate in subglacial discharge measured nearby (~600m a.s.l.), suggesting either a relation with cavity opening at the glacier bed or a rapid change in ice dynamics causing variation in stress components. This variation depends on the initial condition of the cavity, basal sliding and ice rheology. We try to identify from our observations, which one is likely to be the main control despite the limited range of data.
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Lefeuvre, Pierre-Marie; Jackson, Miriam; Lappegard, Gaute & Hagen, Jon Ove Methlie
(2013).
Impact of small-scale distribution of basal pressure for subglacial hydrology.
Show summary
With the ongoing development of 2D subglacial hydrological models, new challenges to simulate the geometry of the drainage system arise notably as their resolution becomes finer. Indeed, the influence of small-scale ice mechanics and small-scale bed topography on subglacial water and ice flow is more likely to take over large-scale forcing. At the Svartisen Subglacial Laboratory (SSL - 200 m below the ice surface), we investigate the importance of basal normal pressure on constraining water flow path over different time scale and hypothesise its importance for water transfer from a channelized drainage system to a distributed one. Twenty years of field observations of normal basal pressure reveal short-lived pressure events, which are assumed to be related to the seasonal development of the hydrological system. We analyse their frequency and amplitude in relation to subglacial runoff measured close to a subglacial tunnel intake located 600-500m above the glacier snout. These events are characterised by a drop in pressure of as much as 1 MPa in a matter of several hours and a sudden rise reaching more than twice the overburden pressure. The cause of this phenomenon seems to be the melting/migration of subglacial channels. Their occurrence is linked to periods of melt and rainfall, when the high capacity drainage system is pressurized above the ice overburden pressure. Then, as water pressure becomes lower than the ice flotation level, the centre part of channels is decoupled from the glacier bed. This decrease in contact area between the ice and the bed produces stresses greater than the mean ice overburden pressure around the channel sides. As a consequence, the flooded area surrounding the high capacity drainage system is sealed off by this large increase in pressure, creating local storage as mentioned in other studies. This water retention can be a highly significant feedback for ice dynamics creating large areas of high pressure that can be reactivated during speed-up events or a surge. In this study, we provide a long-term analysis of the occurrence of those events and infer their significance for maintaining areas of high water pressure over different time-scales (days, months and years) as well as for the basal drag. Finally, we discuss the importance of small-scale observations in the light of measurements showing very strong spatial disparities in normal pressure for two pairs of sensors located less than a meter apart. Discharge measurements provide further insights into the overall behaviour of the subglacial system. Strong correlation with subglacial normal pressure demonstrates the existence of rare global events. In contrast, locally independent events are more frequent suggesting very variable water flow paths and a more distributed drainage system. These last observations suggest periods of water flow controlled mainly by small-scale pressure distribution and small-scale topography. These results highlight the importance of the transition between high and low pressurised drainage system regarding local water storage and its possible impact on ice dynamics. As the resolution of models increases, new small-scale processes will have to be included.
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Lefeuvre, Pierre-Marie; Jackson, Miriam; Lappegard, Gaute & Hagen, Jon Ove Methlie
(2013).
Small-Scale Variation in Basal Pressure and their Interpretation.
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Nuth, Christopher; Kohler, Jack; Schellenberger, Thomas; Schuler, Thomas; Kääb, Andreas & Hagen, Jon Ove Methlie
(2013).
Combining remote sensing and surface mass balance observations/modeling to partition mass changes of Kronebreen, northwest Svalbard.
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Etzelmuller, Bernd; Westermann, Sebastian; Berntsen, Terje Koren; Dunse, Thorben; Gisnås, Kjersti & Hagen, Jon Ove Methlie
[Show all 12 contributors for this article]
(2013).
CRYOMET – Concept and Results for Bridging Models Between the Atmosphere and the Terrestrial Cryosphere (Glacier and Permafrost).
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Dunse, Thorben; Schellenberger, Thomas; Hagen, Jon Ove Methlie; Kääb, Andreas; Schuler, Thomas & Reijmer, Carleen
(2013).
On a major surge of Austfonna.
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Etzelmuller, Bernd; Westermann, Sebastian; Berntsen, Terje Koren; Gisnås, Kjersti; Hagen, Jon Ove Methlie & Kristjansson, Jon Egill
[Show all 10 contributors for this article]
(2013).
Bridging models for the terrestrial cryosphere and the atmosphere - The CryoMET project.
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Schuler, Thomas; Dunse, Thorben; Eiken, Trond & Hagen, Jon Ove Methlie
(2013).
Considering orographic enhancement to downscale precipitation: resolving the accumulation asymmetry and deriving a 55 year accumulation history of Austfonna, Svalbard.
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Westermann, Sebastian; Berntsen, Terje; Etzelmuller, Bernd; Gisnås, Kjersti; Hagen, Jon Ove Methlie & Kristjansson, Jon Egill
[Show all 8 contributors for this article]
(2013).
The CryoMet project - combining deterministic and probabilistic downscaling to model snow depth over a wide range of scales.
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Dunse, Thorben; Schuler, Thomas; Hagen, Jon Ove Methlie & Eiken, Trond
(2013).
Ground-based monitoring of snowcover, firn area and glacier facies of Austfonna, Svalbard, to validate and improve PolarWRF climate simulations.
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Nuth, Christopher; Kohler, Jack; König, Max; Hagen, Jon Ove Methlie; Kääb, Andreas & Moholdt, Geir
(2012).
The Svalbard Glacier Database V1 And V2: creation, parameters and changes.
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Nuth, Christopher; Kohler, Jack; Köhler, Andreas; Schuler, Thomas; Chapuis, Anne & Altena, Bas
(2012).
Observing the Kronebreen glacier system from the ground, by air and space, and through seismic waves.
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Dunse, Thorben; Schuler, Thomas; Hagen, Jon Ove Methlie; Reijmer, Carleen; Nuth, Christopher & Kääb, Andi
(2012).
Seasonal and interannual velocity variations of two outlet glaciers of Austfonna, Svalbard, inferred by continuous GPS measurements.
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Schellenberger, Thomas; Heid, Torborg; Dunse, Thorben; Nuth, Christopher; Reijmer, Carleen & Kohler, Jack
[Show all 7 contributors for this article]
(2012).
Calving flux of Svalbards tidewater glaciers estimated from remote sensing-based surface velocities
.
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Schellenberger, Thomas; Heid, Torborg; Dunse, Thorben; Nuth, Christopher; Kohler, Jack & Hagen, Jon Ove Methlie
(2012).
Calving flux of Svalbards tidewater glaciers estimated from remote sensing-based surface velocities
.
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Westermann, Sebastian; Berntsen, Terje Koren; Etzelmuller, Bernd; Gisnås, Kjersti; Hagen, Jon Ove Methlie & Kristjansson, Jon Egill
[Show all 8 contributors for this article]
(2012).
The CryoMET project – combining deterministic and probabilistic downscaling to model snow depth over a wide range of scales.
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Østby, Torbjørn; Schuler, Thomas; Hagen, Jon Ove Methlie; Hock, Regine & Reijmer, Carleen
(2012).
The role of subsurface heat exchange: energy partitioning at Austfonna ice cap, Svalbard, over 2004-2008.
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Dunse, Thorben; Schuler, Thomas; Hagen, Jon Ove Methlie & Reijmer, Carleen
(2011).
Continuous GPS surface velocity measurements on two fast flowing outlet glaciers of Austfonna, Svalbard.
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Østby, Torbjørn; Schuler, Thomas; Hagen, Jon Ove Methlie; Reijmer, Carleen & Hock, Regine
(2011).
Climatic mass balance of Austfonna ice cap, Svalbard over 2004-2007, from a distributed, coupled energy balance and snow pack model.
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Schuler, Thomas; Dunse, Thorben; Eiken, Trond; Hagen, Jon Ove Methlie; Moholdt, Geir & Østby, Torbjørn
(2011).
A framework for modeling climatic mass balance from reanalysis data - Austfonna, Svalbard.
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Østby, Torbjørn; Schuler, Thomas; Hagen, Jon Ove Methlie; Hock, Regine & Reijmer, Carleen
(2011).
Calibrating a physically based energy and climatic mass balance model at Austfonna ice cap, Svalbard.
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Hagen, Jon Ove Methlie; Dunse, Thorben; Eiken, Trond; Moholdt, Geir; Nuth, Christopher & Schuler, Thomas
(2010).
GLACIODYN - The response of Arctic glaciers to global warming.
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Nuth, Christopher; Schuler, Thomas; Kohler, Jack & Hagen, Jon Ove Methlie
(2010).
Combining mass balance measurements/modeling with geodetic elevation changes: A case study from Kongsvegen and Holtedahlfonna/Kronebreen.
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Dunse, Thorben; Greve, Ralf; Schuler, Thomas & Hagen, Jon Ove Methlie
(2010).
Investigating surge behaviour versus quasi-permanent fast flow of the Austfonna ice cap, Svalbard, by numerical modelling.
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Schuler, Thomas; Dunse, Thorben; Eiken, Trond; Hagen, Jon Ove Methlie; Moholdt, Geir & Nuth, Christopher
(2010).
A surface mass balance history of Austfonna, Svalbard, derived from reanalysis data.
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Nuth, Christopher; Schuler, Thomas; Kohler, Jack; Hagen, Jon Ove Methlie & Kääb, Andreas Max
(2010).
Combining elevation changes and mass balance on Kongsvegen and Kronebreen.
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Nuth, Christopher; Schuler, Thomas; Kohler, Jack; Hagen, Jon Ove Methlie & Engelhardt, Markus
(2010).
Combining surface mass balance with geodetic elevation changes: Examples from Kongsvegen and Holtedahlfonna.
-
Østby, Torbjørn; Schuler, Thomas & Hagen, Jon Ove Methlie
(2010).
Distributed Energy and Surface Mass Balance at Austfonna Ice Cap, Svalbard.
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Nuth, Christopher; Moholdt, Geir; Kohler, Jack & Hagen, Jon Ove Methlie
(2009).
Geometric Changes of Svalbard glaciers and contribution to sea-level rise.
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Nuth, Christopher; Kääb, Andreas Max; Moholdt, Geir; Kohler, Jack & Hagen, Jon Ove Methlie
(2009).
Increasing volume loss of southern Svalbard glaciers revealed by DEM comparison.
-
Moholdt, Geir; Nuth, Christopher & Hagen, Jon Ove Methlie
(2009).
Repeat track ICESat altimetry over Austfonna and Devon ice caps.
-
Moholdt, Geir; Nuth, Christopher & Hagen, Jon Ove Methlie
(2009).
Recent elevation changes of Arctic glaciers derived from repeat track ICESat altimetry.
-
Müller, Karsten; Anschütz, Helgard; Sinisalo, Anna Katariina; Hamran, Svein-Erik; Hagen, Jon Ove Methlie & McConnell, Joseph
[Show all 7 contributors for this article]
(2009).
Surface mass balance along the Norwegian/U.S. scientific traverse across East Antarctica.
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Nuth, Christopher; Schuler, Thomas; Kohler, Jack & Hagen, Jon Ove Methlie
(2009).
Glacier dynamics estimated using mass balance and elevation change data: A case study of two NW Svalbard glaciers.
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Müller, Karsten; Sinisalo, Anna Katariina; Anschütz, Helgard; Hamran, Svein-Erik; Hagen, Jon Ove Methlie & McConnell, Joseph
(2009).
An 860km accumulation rate profile on the East Antarctic plateau derived by GPR.
-
Hagen, Jon Ove Methlie
(2009).
Isbreer.
-
Hagen, Jon Ove Methlie
(2009).
Om isbreforskning i det internasjonlae polaråret.
-
Müller, Karsten; Albert, Mary; Hamran, Svein-Erik & Hagen, Jon Ove Methlie
(2008).
Radar Scattering Zones across Dronning Maud Land, East Antarctica.
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Müller, Karsten; Hamran, Svein-Erik; Hagen, Jon Ove Methlie & Sinisalo, Anna Katariina
(2008).
Relation between GPR, SAR and accumulation rate in the dry-snow zone of East Antarctica.
-
Hagen, Jon Ove Methlie
(2008).
Arctic Glaciers and Ice caps – impacts on global sea level.
-
Hagen, Jon Ove Methlie
(2008).
Arctic Glaciers and Ice caps – impacts on global sea level.
-
Moholdt, Geir & Hagen, Jon Ove Methlie
(2008).
A new DEM of Austfonna ice cap by combining SAR intereferometry and ICESat altimetry.
-
Moholot, Geir; Hagen, Jon Ove Methlie & Eiken, Trond
(2008).
Geometric changes of Austfonna ice cap.
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Schuler, Thomas; Dunse, Thorben; Eiken, Trond; Hagen, Jon Ove Methlie; Moholot, Geir & Taurisano, Andrea
(2008).
The accumulation pattern of Austfonna, Svalbard.
-
-
Hagen, Jon Ove Methlie; Eiken, Trond; Schuler, Thomas; Dunse, Thorben; Melvold, Kjetil & Moholot, Geir
[Show all 9 contributors for this article]
(2008).
Recent changes in surface mass balance of the Austfonna ice cap, Svalbard.
-
Dunse, Thorben; Schuler, Thomas & Hagen, Jon Ove Methlie
(2008).
Application of a numerical ice sheet model on Austfonna, Svalbard - model preparations and input data.
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Dunse, Thorben; Schuler, Thomas; Hagen, Jon Ove Methlie; Eiken, Trond; Moholot, Geir & Taurisano, Andrea
[Show all 8 contributors for this article]
(2008).
Glacier facies transitions on Austfonna, Svalbard, derived from ground-penetrating radar.
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Moholot, Geir; Dunse, Thorben; Eiken, Trond; Hagen, Jon Ove Methlie; Schuler, Thomas & Brandt, Ola
(2008).
Geodetic mass balance of Vestfonna, Austfonna and Kvitøyjøkulen ice caps since 1983.
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Schuler, Thomas; Dunse, Thorben; Eiken, Trond; Hagen, Jon Ove Methlie; Moholot, Geir & Nuth, Christopher
(2008).
A 50 year accumulation history of Austfonna, Svalbard.
-
Nuth, Christopher; Moholot, Geir; Kohler, Jack; Hagen, Jon Ove Methlie & Faste-Aas, Harald
(2008).
Rapid surface elevation losses of Spitsbergen glaciers (1936- 1990-2005).
-
Dunse, Thorben; Hagen, Jon Ove Methlie & Schuler, Thomas Vikhamar
(2011).
Glacier dynamics and subsurface classification of Austfonna, Svalbard: Inferences from observations and modelling.
Unipub forlag.
-
Nuth, Christopher; Hagen, Jon Ove Methlie; Schuler, Thomas; Kääb, Andreas & Kohler, Jack
(2011).
Quantification and interpretation of glacier elevation changes.
Unipub forlag.