Jon Ove Hagen

Jon Ove Hagen
University of Oslo · Department of Geosciences

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179
Publications
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Publications

Publications (179)
Article
Changes in glacier facies (glacier zones), such as firn or superimposed ice (SI), are good indicators of glacier response to climate change. They are especially important for fast-warming Svalbard, where only a few glaciers are under glaciological mass balance monitoring. This paper presents a first study of changes of glacier facies extent for thr...
Article
Full-text available
Compared to other Arctic ice masses, Svalbard glaciers are low-elevated with flat interior accumulation areas, resulting in a marked peak in their current hypsometry (area-elevation distribution) at ~450 m above sea level. Since summer melt consistently exceeds winter snowfall, these low-lying glaciers can only survive by refreezing a considerable...
Article
Full-text available
Since the first estimates of Svalbard-wide glacier mass balance were made in the early 2000s, there has been great progress in remote sensing and modeling of mass balance, existing field records have been extended, field records at new locations have been added, and there has been considerable environmental change. There is a wide spread in the ava...
Article
Full-text available
Glacier-mass changes are a reliable indicator of climate change. On behalf of the worldwide network of glacier observers, we urge parties to the United Nations Framework Convention on Climate Change to boost international cooperation in monitoring these changes, and to include the results in the Paris agreement’s global stocktake.
Article
Full-text available
The climate in Svalbard is undergoing amplified change compared to the global mean. This has major implications for runoff from glaciers and seasonal snow on land. We use a coupled energy balance–subsurface model, forced with downscaled regional climate model fields, and apply it to both glacier-covered and land areas in Svalbard. This generates a...
Article
Full-text available
The climate in Svalbard is undergoing amplified change compared to the global mean. This has major implications for runoff from glaciers and seasonal snow on land. We use a coupled energy balance – subsurface model, forced with downscaled regional climate model fields, and apply it to both glacier-covered and land areas in Svalbard. This generates...
Article
Full-text available
We used a finite element model to interpret anti-correlated pressure variations at the base of a glacier to demonstrate the importance of stress redistribution in the basal ice. We first investigated two pairs of load cells installed 20 m apart at the base of the 210 m thick Engabreen glacier in Northern Norway. The load cell data for July 2003 sho...
Poster
Poster presentation at 17th Annual ČAG Conference - State of geomorphological research in 2017
Article
The influence of the ‘Little Ice Age’ (LIA) on the glaciers of Svalbard has been well documented for a long time. This paper presents new data on the LIA maximum glacier extent and retreat by aerial photo interpretation and Geographic Information Systems (GIS) tools. We also make cartography where all results are shown in greater detail. During the...
Article
Full-text available
Basin-3, the largest outlet basin of the Austfonna ice cap, started to surge in autumn 2012. A maximum velocity of 18.8 m d⁻¹ was found in December 2012 / January 2013. Here we present a time series of area wide velocity fields from synthetic aperture radar (SAR) offset tracking and Global Positioning System (GPS) data in the aftermath of the veloc...
Article
Full-text available
Estimating the long-term mass balance of the high-Arctic Svalbard archipelago is difficult due to the incomplete geodetic and direct glaciological measurements, both in space and time. To close these gaps, we use a coupled surface energy balance and snow pack model to analyse the mass changes of all Svalbard glaciers for the period 1957–2014. The m...
Article
Svalbard climate is undergoing amplified change with respect to the global mean. Changing climate conditions directly affect the evolution of the seasonal snowpack, through its impact on accumulation, melt and moisture exchange. We analyze long-term trends and spatial patterns of seasonal snow conditions in Svalbard between 1961 and 2012. Downscale...
Article
Full-text available
Longterm mass balance of all glaciers of the high Arctic Svalbard archipelago is difficult to achieve due to spatial and temporal incompleteness of geodetic and direct glaciological measurements. To close these gaps, we use a coupled surface energy balance and snow pack model to analyze Svalbard glacier mass changes and its evolution for the period...
Article
Full-text available
Observations show that glaciers around the world are in retreat and losing mass. Internationally coordinated for over a century, glacier monitoring activities provide an unprecedented dataset of glacier observations from ground, air and space. Glacier studies generally select specific parts of these datasets to obtain optimal assessments of the mas...
Article
Full-text available
Mass loss from glaciers and ice sheets currently accounts for two-thirds of the observed global sea-level rise and has accelerated since the 1990s, coincident with strong atmospheric warming in the polar regions. Here we present continuous GPS measurements and satellite synthetic-aperture-radar-based velocity maps from Basin-3, the largest drainage...
Article
Full-text available
Basal pressure has been recorded at the Svartisen Subglacial Laboratory, northern Norway, for 20 years, and is measured by load cells installed at the ice-rock interface under ∼200 m of glacier ice. Synchronous pressure variations between load cells are investigated as evidence of stress redistribution and hydrological bed connectivity. A running P...
Article
Full-text available
The Randolph Glacier Inventory (RGI) is a globally complete collection of digital outlines of glaciers, excluding the ice sheets, developed to meet the needs of the Fifth Assessment of the Intergovernmental Panel on Climate Change for estimates of past and future mass balance. The RGI was created with limited resources in a short period. Priority w...
Article
Full-text available
The Randolph Glacier Inventory (RGI) is a globally complete collection of digital outlines of glaciers, excluding the ice sheets, developed to meet the needs of the Fifth Assessment of the Intergovernmental Panel on Climate Change for estimates of past and future mass balance. The RGI was created with limited resources in a short period. Priority w...
Article
Only few reliable records are available covering more than 5 years of meteorological conditions on Arctic glaciers. Here, we report on the operation of an automatic weather station at the Austfonna ice cap, Svalbard, over an 8-year period from 2004 to 2012. Time series of measured and derived quantities are analysed to characterize meteorological c...
Article
Full-text available
Mass loss from glaciers and ice sheets currently accounts for two-thirds of the observed global sea-level rise and has accelerated since the 1990s, coincident with strong atmospheric warming in the Polar Regions. Here we present continuous GPS measurements and satellite synthetic aperture radar based velocity maps from the Austfonna ice cap, Svalba...
Article
[1] Many challenges remain for estimating the Antarctic ice sheet surface mass balance (SMB), which represents a major uncertainty in predictions of future sea-level rise. Validating continental scale studies is hampered by the sparse distribution of in situ data. Here we present a 26 year mean SMB of the Fimbul ice shelf in East Antarctica between...
Article
Winter balance is an important metric for assessing the change on glaciers and ice caps, yet measuring it using ground-based techniques can be challenging. We use the European Space Agency prototype Airborne SAR/Interferometric Radar Altimeter System (ASIRAS) to extract snow depths from the received altimeter waveforms over Austfonna ice cap, Svalb...
Article
Full-text available
We present a multi-temporal digital inventory of Svalbard glaciers with the most recent from the late 2000s containing 33 775 km2 of glaciers covering 57% of the total land area of the archipelago. At present, 68% of the glacierized area of Svalbard drains through tidewater glaciers that have a total terminus width of ~ 740 km. The glacierized area...
Article
We apply a physically based coupled surface energy balance and snowpack model to a site close to the equilibrium line on Austfonna ice cap, Svalbard, over the 2004–08 melt seasons, to explain contributions to the energy available for melting and to quantify the significance of refreezing. Themodel is forced using in situ meteorological measurements...
Article
Approximately 50 researchers attended the Ice2sea North/South Glacier Workshop at the Geological Survey of Denmark and Greenland (GEUS). The aim of the workshop was to highlight the importance of changes in Northern and Southern Hemisphere near-polar glacier systems, which are subject to rapid climate warming from the atmosphere and ocean. Other go...
Article
Full-text available
We present a multi-temporal digital inventory of Svalbard glaciers with the most recent from the late 2000s containing 33 775 km2 of glaciers, or 57% of the total land area of the archipelago. At present, 68% of the glaciated area of Svalbard drains through tidewater glaciers that have a summed terminus width of ~ 740 km. The glaciated area over th...
Article
Full-text available
Glaciers distinct from the Greenland and Antarctic Ice Sheets are losing large amounts of water to the world’s oceans. However, estimates of their contribution to sea level rise disagree. We provide a consensus estimate by standardizing existing, and creating new, mass-budget estimates from satellite gravimetry and altimetry and from local glaciolo...
Article
Predictions of the future climate are generally based on atmospheric models operating on coarse spatial scales. However, the impact of a changing climate on most elements of the cryosphere becomes manifest on much smaller scales, which complicates sound predictions e.g. on glacier and permafrost development. CryoMET is a collaborative project betwe...
Article
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...
Article
Full-text available
A large part of the ice discharge from ice caps and ice sheets occurs through spatially limited flow units that may operate in a mode of steady flow or cyclic surge behaviour. Changes in the dynamics of distinct flow units play a key role in the mass balance of Austfonna, the largest ice cap on Svalbard. The recent net mass loss of Austfonna was do...
Article
As part of the IPY GLACIODYN project (The response of Arctic glaciers to global warming) the mass balance of the Austfonna Ice Cap has been studied. The Austfonna ice cap (8120 km2) is by far the larges ice cap in Svalbard and one of the largest in the Arctic. Studies have been focused on 1) Surface mass balance by direct measurements 2) Geodetic m...
Article
This study independently quantifies geodetic elevation change and models surface mass balance to solve the continuity equation. The approach is tested on two dynamically different glaciers, Kongsvegen and Kronebreen in northwest Svalbard, through two time epochs, 1966–1990/95 (I) and 1990/95–2007 (II). On Kongsvegen, a dynamically inactive glacier,...
Article
High-frequency radar data were collected during the Norwegian-US traverse from South Pole to Troll Station in 2008/09. The traverse route went directly over the Recovery catchment upstream of Recovery ice stream. This area consists of four lake type features previously identified from remote sensing data and recently studied with a low frequency ra...
Article
We show first results of ground based radar measurements, obtained with a CRESIS Ku-band FMCW radar. The radar was operated to cover the frequency band of the CryoSat-2 synthetic aperture interferometric radar altimeter (SIRAL) and the airborne version, Airborne Synthetic Aperture and Interferometric Radar Altimeter System (ASIRAS) carried by the D...
Article
A coupled energy balance and snow pack model has been applied to every grid cell of a 1000m resolution DEM for the Austfonna ice cap (~8000 km^2), Svalbard, to investigate energy fluxes, refreezing and the climatic mass balance. The model was forced by hourly data of air temperature, humidity and wind speed from an automatic weather station (AWS) p...
Conference Paper
Glaciers (including the Ice Caps) are major contributors to the observed Sea Level Rise both regionally and globally. We have reasonably good estimates of small scale contributions and contributions from selected regions, and also gross estimates of global contributions. Gaps in knowledge are known and not all of them can be closed. Yet, the number...
Article
Full-text available
A large part of the ice discharge from ice caps and ice sheets occurs through spatially limited flow units that may operate in a mode of steady flow or cyclic surge behaviour. Changes in the dynamics of distinct flow units play a key role in the mass balance of Austfonna, the largest ice cap on Svalbard. The recent net mass loss of Austfonna was do...
Article
Backscatter from an aggregate of inhomogeneities combine to form an apparent surface reflection particularly in relation to interferometric synthetic aperture radar. The depth zφ of this reflection can reside well below the true surface when the transmissivity at the interface between air and the aggregate is high. Snow and ice provide good example...
Article
We have measured the glacier area changes in the central Southern Alps, New Zealand, between 1978 and 2002 and have compiled the 2002 glacier outlines using an image scene from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). Three automated classification methods were tested: (1) band ratio, (2) normalized-difference sno...
Article
Full-text available
In the first week of September 2010, international experts on glacier monitoring convened in Zermatt, Switzerland, for two separate but related meetings. They discussed glacier data compiled over the past 150 years and how to improve this dataset to meet the challenges of the 21st century, pre-sented latest results from in situ and remotely sensed...
Article
A large part of the ice flux within ice caps occurs through spatially limited fast-flowing units. Some of them permanently maintain fast flow, whereas others operate in an oscillatory mode, characterized by short-lived active phases followed by long quiescent phases. This surge-type behaviour results from intrinsic rather than external factors, thu...
Article
Full-text available
In the first week of September 2010, international experts on glacier monitoring convened in Zermatt, Switzerland, for two separate but related meetings. They discussed glacier data compiled over the past 150 years and how to improve this dataset to meet the challenges of the 21st century, pre- sented latest results from in situ and remotely sensed...
Article
High-frequency radar data were collected on the second leg of the Norwegian-US traverse from South Pole to Troll Station in 2008/09. The traverse route went directly over all four Recovery Lakes, which have been identified previously from remote sensing data. We used a ground-based high-frequency FMCW radar with a center frequency of 1.75 GHz. The...
Article
The Arctic region is more affected by climate change than the lower latitudes. Glaciers and ice caps are sensitive indicators of climate change, and there is a high demand for more accurate quantifications of glacier changes in the Arctic. ICESat laser altimetry has been a popular tool for assessing recent elevation changes of the Greenland ice she...
Article
We show first results from the 2009-2010 summer season glaciology field campaign on Fimbulisen, East Antarctica. Previous modeling and remote sensing studies imply that this ice shelf has a strong negative mass balance. Yet the most recent measurements under the ice shelf indicate that the basal melt rates are overestimated and the ice shelf may be...
Article
We have tested three methods for estimating 2003–2008 elevation changes of Svalbard glaciers from multi-temporal ICESat laser altimetry: (a) linear interpolation of crossover points between ascending and descending tracks, (b) projection of near repeat-tracks onto common locations using Digital Elevation Models (DEMs), and (c) least-squares fitting...
Article
Full-text available
Snow accumulation and its variability on the East Antarctic plateau are poorly understood due to sparse and regionally confined measurements. We present a 5.3 GHz (C-band) ground-penetrating radar (GPR) profile with a total length of 860 km recovered during the joint Norwegian–US International Polar Year traverse 2007/08. Mean surface mass balance...
Article
We show the first results from the 2009-2010 summer season glaciology field campaign on Fimbulisen, the largest iceshelf in Dronning Maud Land (DML), Antarctica. The iceshelf is fed by Jutulstraumen, the largest outlet glacier from DML, and it plays an important role in processes in the Weddell Sea area. Previous modeling and remote sensing studies...
Article
Full-text available
2010. [1] We compare satellite altimetry from the Ice, Cloud, and Land Elevation Satellite (ICESat, 2003–2007) to older topographic maps and digital elevation models (1965– 1990) to calculate long-term elevation changes of glaciers on the Svalbard Archipelago. Results indicate significant thinning at most glacier fronts with either slight thinning...
Article
Full-text available
The dynamics and mass balance regime of the Austfonna ice cap, the largest glacier on Svalbard, deviates significantly from most other glaciers in the region and is not fully understood. We have compared ICESat laser altimetry, airborne laser altimetry, GNSS surface profiles and radio echo-sounding data to estimate elevation change rates for the pe...
Conference Paper
Surface mass balance (SMB) on the East Antarctic Plateau (EAP) and its variability is poorly understood due to sparse and regionally confined measurements. The joint Norwegian - U.S. IPY traverse 2007-2009 traveled east of the ice divide in Dronning Maud Land from the coast to South Pole and back via the newly discovered Recovery Lakes. We present...
Article
Glacial dynamic fluxes are estimated by combining measured and modelled mass balance data with geodetic elevation changes. Kongsvegen (105 km2) and Holtedahlfonna/Kronebreen (370 km2) are two dynamically different glaciers located in Northwest Spitsbergen (79°N 13°W). Mass balance measurements have been acquired since 1986 and 2003, RESPECTIVELY. M...
Article
The aim of GLACIODYN is to reduce the uncertainties in Arctic Glaciers and Ice Cap (GIC) contribution to sea level changes. This involves to include calving in mass budget calculations, improve process understanding of calving and basal sliding and include dynamics in modeling of future glacier response. Selected target GICs have been studied in th...
Article
Full-text available
The Austfonna ice cap covers an area of 8120 km2 and is by far the largest glacier on Svalbard. Almost 30% of the entire area is grounded below sea-level, while the figure is as large as 57% for the known surge-type basins in particular. Marine ice dynamics, as well as flow instabilities presumably control flow regime, form and evolution of Austfon...
Article
The dynamics and mass balance regime of the Austfonna ice cap, the largest glacier on Svalbard, deviate significantly from most other glaciers in the region and is not fully understood. We have compared ICESat laser altimetry, airborne laser altimetry, GNSS surface profiles and radio echo-sounding data to estimate elevation change rates for the per...
Article
Full-text available
Geometric changes on a sample of Svalbard glaciers were studied using subtraction of repeat digital terrain models to determine early surge-stage dynamics. Changes in surface features were also analyzed. A number of new surges were found for glaciers not known to have surged previously. The surge development could be followed through three stages,...
Article
In spring during 2004-07 we conducted ground-penetrating radar (GPR) measurements on the Austfonna ice cap, Svalbard, with the original aim of mapping the thickness and distribution of winter snow. Here, we further exploit the information content of the data and derive a multi-year sequence of glacier-facies distribution that provides valuable spat...
Article
Deep subpermafrost aquifers are highly climate-dependent, with the permafrost as an aquitard preventing groundwater recharge and discharge. A study from the high-arctic island of Spitsbergen, Svalbard, shows that during a glacial to interglacial phase, both the permafrost and the glacier regime will respond to climatic changes, and a glacier-fed gr...
Article
Full-text available
The purpose of this study is to describe the current state of tidewater glaciers in Svalbard as an extension of the inventory of Hagen et al. (1993). The ice masses of Svalbard cover an area of ca 36 600 km2 and more than 60% of the glaciated areas are glaciers which terminate in the sea at calving ice-cliffs. Recent data on the geometry of glacier...