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Now showing items 1-58 of 58
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Abstract Using global Sentinel-1 radar backscatter data, we systematically map the locations of glaciers with surge-type activity during 2017–22. Patterns of pronounced increases or decreases in the strongest backscatter ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Following the 130 ± 5 × 106 m3 detachment of the Sedongpu Glacier, south-eastern Tibet, in October 2018, the Sedongpu Valley, which drains into the Yarlung Tsangpo (Brahmaputra) River, underwent rapid large-volume landscape ...
(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2023)
Abstract Glaciers distinct from the Greenland and Antarctic ice sheets are currently losing mass rapidly with direct and severe impacts on the habitability of some regions on Earth as glacier meltwater contributes to ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
The CryoGrid community model is a flexible toolbox for simulating the ground thermal regime and the ice–water balance for permafrost and glaciers, extending a well-established suite of permafrost models (CryoGrid 1, 2, and ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
Abstract. Landslides are a major geohazard that cause thousands of fatalities every year. Despite their importance, identifying unstable slopes and forecasting collapses remains a major challenge. In this study, we use the ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
In the Karakoram, dozens of glacier surges occurred in the past two decades, making the region one of its global hot spots. Detailed analyses of dense time series from optical and radar satellite images revealed a wide ...
A Consistent Framework for Coupling Basal Friction With Subglacial Hydrology on Hard-Bedded Glaciers
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
Below hard-bedded glaciers, both basal friction and distributed subglacial drainage are thought to be controlled by a network of cavities. Previous coupled hydro-mechanical models, however, describe cavity-driven friction ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
Glacial lakes are an important and dynamic component of terrestrial meltwater storage, responding to climate change and glacier retreat. Although there is evidence of rapid worldwide growth of glacial lakes, changes in ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
In recent years a vast amount of glacier surface velocity data from satellite imagery has emerged based on correlation between repeat images. Thereby, much emphasis has been put on the fast processing of large data volumes ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
Digitized aerial images were used to monitor the evolution of perennially frozen debris and polythermal glacier ice at the intensely investigated Gruben site in the Swiss Alps over a period of about 50 years. The photogrammetric ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
Every spring the mechanical river ice break-up and associated ice-runs or flooding pose a threat to communities at Northern latitudes. Monitoring and mitigation efforts along remote Arctic rivers are possible but logistically ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
Ice marginal lakes are a dynamic component of terrestrial meltwater storage at the margin of the Greenland Ice Sheet. Despite their significance to the sea level budget, local flood hazards and bigeochemical fluxes, there ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
Svalbard Integrated Arctic Earth Observing System (SIOS) is an international partnership of research institutions studying the environment and climate in and around Svalbard. SIOS is developing an efficient observing system, ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
Glacial hydrology plays an important role in the control of glacier dynamics, of sediment transport, and of fjord and proglacial ecosystems. Surface meltwater drains through glaciers via supraglacial, englacial and subglacial ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
Permafrost is present within almost all of the Antarctic's ice-free areas, but little is known about spatial variations in permafrost temperatures except for a few areas with established ground temperature measurements. ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
Abstract. Cold glacier beds, i.e., where the ice is frozen to its base, are widespread in polar regions. Common theories state that stable permafrost should exist under glacier beds on shorter timescales, varying from years ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
Societal dependence on, and commercial and scientific exploitation of Earth-Oriented remote sensing from satellites is growing at an exponential rate. The comprehensive EU Copernicus programme provides a major contribution ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
In Kyrgyzstan, outburst flood disasters from glacial lakes are increasing. An example is the sudden drainage on 8 August 2019 of the Toguz-Bulak glacial lake in the Tosor river basin of the northern Tien Shan region. In ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
Active rock glaciers represent the best visual expression of mountain permafrost that can be mapped and monitored directly using remotely sensed data. Active rock glaciers are bodies that consist of a perennially frozen ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
Abstract Negribreen, a tidewater glacier located in central eastern Svalbard, began actively surging after it experienced an initial collapse in summer 2016. The surge resulted in horizontal surface velocities of more than ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
Abstract Velocities within an icefall are typically the fastest within a glacier system and experience complex flow. The combination of convergent and fast flow, and steep slope generate a quickly changing and intensely ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
Abstract. The PlanetScope constellation consists of ∼150 optical cubesats that are evenly distributed like strings of pearls on two orbital planes, scanning the Earth's land surface once per day with an approximate spatial ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
Glacier mass balance has been estimated on individual glacier and regional scales using repeat digital elevation models (DEMs). DEMs often have gaps in coverage (“voids”), the properties of which depend on the nature of ...
Brief communication: Collapse of 4Mm3 of ice from a cirque glacier in the Central Andes of Argentina
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
Abstract. Among glacier instabilities, collapses of large parts of low-angle glaciers are a striking, exceptional phenomenon. So far, merely the 2002 collapse of Kolka Glacier in the Caucasus Mountains and the 2016 twin ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
The measurement of glacier velocity fields using repeat satellite imagery has become a standard method of cryospheric research. However, the reliable discovery of important glacier velocity variations on a large scale is ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
Permafrost is a key element of the cryosphere and an essential climate variable in the Global Climate Observing System. There is no remote-sensing method available to reliably monitor the permafrost thermal state. To ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
Currently, the Sentinel-2 twin satellite constellation of the Copernicus program is in operational mode and generates high repeat acquisitions at high-latitudes during polar day. These pushbroom satellites have a large ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
Glacier flow instabilities can rapidly increase sea level through enhanced ice discharge. Surge-type glacier accelerations often occur with a decadal to centennial cyclicity suggesting internal mechanisms responsible. ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
With dense SAR satellite data time series it is possible to map surface and subsurface glacier properties that vary in time. On Sentinel-1A and RADARSAT-2 backscatter time series images over mainland Norway and Svalbard, ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
In north-western Tibet (34.0∘ N, 82.2∘ E) near lake Aru Co, the entire ablation areas of two glaciers (Aru-1 and Aru-2) suddenly collapsed on 17 July and 21 September 2016. The masses transformed into ice avalanches with ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
In permafrost areas, seasonal freeze-thaw cycles result in upward and downward movements of the ground. For some permafrost areas, long-term downward movements were reported during the last decade. We measured seasonal and ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
Abstract. Glacier surface mass balance observations in the Tien Shan and Pamir are relatively sparse and often discontinuous. Nevertheless, glaciers are one of the most important components of the high-mountain cryosphere ...
(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2018)
Surges and glacier avalanches are expressions of glacier instability, and among the most dramatic phenomena in the mountain cryosphere. Until now, the catastrophic collapse of a glacier, combining the large volume of surges ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
To assess the current state of glacial lakes, we examine the seasonal lake-area changes of 339 glacial lakes in the Teskey and Kungoy Ranges of the Issyk-Kul Basin, Kyrgyzstan, during 2013–2016 based on optical satellite ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
Four large drainages from glacial lakes occurred during 2006–2014 in the western Teskey Range, Kyrgyzstan. These floods caused extensive damage, killing people and livestock as well as destroying property and crops. Using ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
Stretching time series further in the past with the best possible accuracy is essential to the understanding of climate change impacts and geomorphological processes evolving on decadal-scale time spans. In the first half ...
(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)
Direct snow depth measurements are sparse, especially in remote areas. In this study, we assess the potential of ICESat laser altimetry for providing snow depths for its operational period 2003–2009 on the example of the ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
Satellite measurements of coseismic displacements are typically based on synthetic aperture radar (SAR) interferometry or amplitude tracking, or based on optical data such as from Landsat, Sentinel-2, SPOT, ASTER, very ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) system on board the Terra (EOS AM-1) satellite has been a source of stereoscopic images covering the whole globe at 15-m resolution with consistent ...
(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)
High Mountain Asia hosts the largest glacier concentration outside the polar regions. These glaciers are important contributors to streamflow in one of the most populated areas of the world. Past studies have used methods ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
The Karakoram mountain range is well known for its numerous surge-type glaciers of which several have recently surged or are still doing so. Analysis of multi-temporal satellite images and digital elevation models have ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
In consideration of the strong atmospheric warming that has been observed since the 1990s in polar regions there is a need to quantify mass loss of Arctic ice caps and glaciers and their contribution to sea level rise. In ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
We computed circum-Arctic surface velocity maps of glaciers and ice caps over the Canadian Arctic, Svalbard and the Russian Arctic for at least two times between the 1990s and 2017 using satellite SAR data. Our analyses ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
Optical satellite products are available at different processing levels. Of these products, terrain corrected (i.e., orthorectified) products are the ones mostly used for glacier displacement estimation. For terrain ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
Acquiring data to analyse change in topography is often a costly endeavour requiring either extensive, potentially risky, fieldwork and/or expensive equipment or commercial data. Bringing the cost down while keeping the ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
When Earth observation satellite systems are designed, one typically prefers a sun-synchronous orbit. However, the first generations of cubesats from Planet were deployed out of the International Space Station (ISS) and ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
Contemporary optical remote sensing satellites or constellations of satellites can acquire imagery at sub-weekly or even daily timescales. These systems have the potential to facilitate intra-seasonal, short-term surface ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
Glacier dynamics play an important role in the mass balance of many glaciers, ice caps and ice sheets. In this study we exploit Radarsat-2 (RS-2) Wide Fine (WF) data to determine the surface speed of Svalbard glaciers in ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
The first of two Sentinel-2 satellites, launched mid-2015, has similar characteristics as the Landsat TM/ETM+/OLI satellites. Together, these satellites will produce a tremendous quantity of optical images worldwide for ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
Using sparsely glaciated southern Norway as a case study, we assess the potential and limitations of ICESat laser altimetry for analysing regional glacier elevation change in rough mountain terrain. Differences between ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
With its temporal resolution of 10 days (five days with two satellites, and significantly more at high latitudes), its swath width of 290 km, and its 10 m and 20 m spatial resolution bands from the visible to the shortwave ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
Mapping of glacier extents from automated classification of optical satellite images has become a major application of the freely available images from Landsat. A widely applied method is based on segmented ratio images ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
This study presents a reconstruction of the seasonal mass balance of Glacier No. 354, located in the Akshiirak range, Kyrgyzstan, from 2003 to 2014. We use a distributed accumulation and temperature-index melt model driven ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
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 ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
Sorted soil circles are a form of periglacial patterned ground that is commonly noted for its striking geometric regularity. They consist of an inner fine domain bordered by gravel rings that rise some decimetres above the ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
Kronebreen and Kongsbreen are among the fastest-flowing glaciers on Svalbard and, therefore, important contributors to the total dynamic mass loss from the archipelago. Here, we present a time series of area-wide surface ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)
Knowledge of water-surface velocities in rivers is useful for understanding a range of river processes. In cold regions, river-ice break up and the related downstream transport of ice debris is often the most important ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)
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 ...