Articles | Volume 11, issue 1
https://doi.org/10.5194/tc-11-553-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/tc-11-553-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
16 Feb 2017
Research article |
| 16 Feb 2017
Frontal destabilization of Stonebreen, Edgeøya, Svalbard
Gamma Remote Sensing, Worbstrasse 225, 3073 Gümligen, Switzerland
Andreas Kääb
Department of Geosciences, University of Oslo, P.O. Box 1047,
Blindern, 0316 Oslo, Norway
Thomas Schellenberger
Department of Geosciences, University of Oslo, P.O. Box 1047,
Blindern, 0316 Oslo, Norway
Related authors
Barbara Widhalm, Annett Bartsch, Tazio Strozzi, Nina Jones, Artem Khomutov, Elena Babkina, Marina Leibman, Rustam Khairullin, Mathias Göckede, Helena Bergstedt, Clemens von Baeckmann, and Xaver Muri
EGUsphere, https://doi.org/10.5194/egusphere-2024-2356, https://doi.org/10.5194/egusphere-2024-2356, 2024
Short summary
Short summary
Mapping soil moisture in Arctic permafrost regions is crucial for various activities, but it is challenging with typical satellite methods due to the landscape's diversity. Seasonal freezing and thawing cause the ground to periodically rise and subside. Our research demonstrates that this seasonal ground settlement, measured with Sentinel-1 satellite data, is larger in areas with wetter soils. This method helps to monitor permafrost degradation.
Aldo Bertone, Nina Jones, Volkmar Mair, Riccardo Scotti, Tazio Strozzi, and Francesco Brardinoni
The Cryosphere, 18, 2335–2356, https://doi.org/10.5194/tc-18-2335-2024, https://doi.org/10.5194/tc-18-2335-2024, 2024
Short summary
Short summary
Traditional inventories display high uncertainty in discriminating between intact (permafrost-bearing) and relict (devoid) rock glaciers (RGs). Integration of InSAR-based kinematics in South Tyrol affords uncertainty reduction and depicts a broad elevation belt of relict–intact coexistence. RG velocity and moving area (MA) cover increase linearly with elevation up to an inflection at 2600–2800 m a.s.l., which we regard as a signature of sporadic-to-discontinuous permafrost transition.
Alessandro Cicoira, Samuel Weber, Andreas Biri, Ben Buchli, Reynald Delaloye, Reto Da Forno, Isabelle Gärtner-Roer, Stephan Gruber, Tonio Gsell, Andreas Hasler, Roman Lim, Philippe Limpach, Raphael Mayoraz, Matthias Meyer, Jeannette Noetzli, Marcia Phillips, Eric Pointner, Hugo Raetzo, Cristian Scapozza, Tazio Strozzi, Lothar Thiele, Andreas Vieli, Daniel Vonder Mühll, Vanessa Wirz, and Jan Beutel
Earth Syst. Sci. Data, 14, 5061–5091, https://doi.org/10.5194/essd-14-5061-2022, https://doi.org/10.5194/essd-14-5061-2022, 2022
Short summary
Short summary
This paper documents a monitoring network of 54 positions, located on different periglacial landforms in the Swiss Alps: rock glaciers, landslides, and steep rock walls. The data serve basic research but also decision-making and mitigation of natural hazards. It is the largest dataset of its kind, comprising over 209 000 daily positions and additional weather data.
Aldo Bertone, Chloé Barboux, Xavier Bodin, Tobias Bolch, Francesco Brardinoni, Rafael Caduff, Hanne H. Christiansen, Margaret M. Darrow, Reynald Delaloye, Bernd Etzelmüller, Ole Humlum, Christophe Lambiel, Karianne S. Lilleøren, Volkmar Mair, Gabriel Pellegrinon, Line Rouyet, Lucas Ruiz, and Tazio Strozzi
The Cryosphere, 16, 2769–2792, https://doi.org/10.5194/tc-16-2769-2022, https://doi.org/10.5194/tc-16-2769-2022, 2022
Short summary
Short summary
We present the guidelines developed by the IPA Action Group and within the ESA Permafrost CCI project to include InSAR-based kinematic information in rock glacier inventories. Nine operators applied these guidelines to 11 regions worldwide; more than 3600 rock glaciers are classified according to their kinematics. We test and demonstrate the feasibility of applying common rules to produce homogeneous kinematic inventories at global scale, useful for hydrological and climate change purposes.
Frank Paul, Livia Piermattei, Désirée Treichler, Lin Gilbert, Luc Girod, Andreas Kääb, Ludivine Libert, Thomas Nagler, Tazio Strozzi, and Jan Wuite
The Cryosphere, 16, 2505–2526, https://doi.org/10.5194/tc-16-2505-2022, https://doi.org/10.5194/tc-16-2505-2022, 2022
Short summary
Short summary
Glacier surges are widespread in the Karakoram and have been intensely studied using satellite data and DEMs. We use time series of such datasets to study three glacier surges in the same region of the Karakoram. We found strongly contrasting advance rates and flow velocities, maximum velocities of 30 m d−1, and a change in the surge mechanism during a surge. A sensor comparison revealed good agreement, but steep terrain and the two smaller glaciers caused limitations for some of them.
Tazio Strozzi, Andreas Wiesmann, Andreas Kääb, Thomas Schellenberger, and Frank Paul
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2022-44, https://doi.org/10.5194/essd-2022-44, 2022
Revised manuscript not accepted
Short summary
Short summary
Knowledge on surface velocity of glaciers and ice caps contributes to a better understanding of a wide range of processes related to glacier dynamics, mass change and response to climate. Based on the release of historical satellite radar data from various space agencies we compiled nearly complete mosaics of winter ice surface velocities for the 1990's over the Eastern Arctic. Compared to the present state, we observe a general increase of ice velocities along with a retreat of glacier fronts.
Andreas Kääb, Tazio Strozzi, Tobias Bolch, Rafael Caduff, Håkon Trefall, Markus Stoffel, and Alexander Kokarev
The Cryosphere, 15, 927–949, https://doi.org/10.5194/tc-15-927-2021, https://doi.org/10.5194/tc-15-927-2021, 2021
Short summary
Short summary
We present a map of rock glacier motion over parts of the northern Tien Shan and time series of surface speed for six of them over almost 70 years.
This is by far the most detailed investigation of this kind available for central Asia.
We detect a 2- to 4-fold increase in rock glacier motion between the 1950s and present, which we attribute to atmospheric warming.
Relative to the shrinking glaciers in the region, this implies increased importance of periglacial sediment transport.
Tazio Strozzi, Dora Carreon-Freyre, and Urs Wegmüller
Proc. IAHS, 382, 179–182, https://doi.org/10.5194/piahs-382-179-2020, https://doi.org/10.5194/piahs-382-179-2020, 2020
Luigi Tosi, Cristina Da Lio, Sandra Donnici, Tazio Strozzi, and Pietro Teatini
Proc. IAHS, 382, 689–695, https://doi.org/10.5194/piahs-382-689-2020, https://doi.org/10.5194/piahs-382-689-2020, 2020
Short summary
Short summary
The Venice coastland forms the major low-lying area in Italy and encompasses a variety of environments, such as farmlands, estuaries, deltas, lagoons and urbanized areas. Since most of the territory lies at a ground elevation below or slightly above the mean sea-level, also a few mm/yr of land subsidence can seriously impacts on the coastal system. In this study, we present an analysis of the vulnerability to relative sea-level rise (RSLR) considering an uneven land subsidence distribution.
Cristian Scapozza, Christian Ambrosi, Massimiliano Cannata, and Tazio Strozzi
Geogr. Helv., 74, 125–139, https://doi.org/10.5194/gh-74-125-2019, https://doi.org/10.5194/gh-74-125-2019, 2019
Short summary
Short summary
A glacial lake outburst flood hazard assessment by satellite Earth observation and numerical modelling was done for the lakes linked to the Thangothang Chhu glacier, Chomolhari area (Bhutan), combining detailed geomorphological mapping, landslide and rock glacier inventories, as well as surface displacements quantified by satellite InSAR. Outburst scenario modelling revealed that only a flood wave can have an impact on the two human settlements located downslope of the glacier.
Nico Mölg, Tobias Bolch, Philipp Rastner, Tazio Strozzi, and Frank Paul
Earth Syst. Sci. Data, 10, 1807–1827, https://doi.org/10.5194/essd-10-1807-2018, https://doi.org/10.5194/essd-10-1807-2018, 2018
Short summary
Short summary
Knowledge about the size and location of glaciers is essential to understand impacts of climatic changes on the natural environment. Therefore, we have produced an inventory of all glaciers in some of the largest glacierized mountain regions worldwide. Many large glaciers are covered by a rock (debris) layer, which also changes their reaction to climatic changes. Thus, we have also mapped this debris layer for all glaciers. We have mapped almost 28000 glaciers covering ~35000 km2.
L. Tosi, T. Strozzi, C. Da Lio, and P. Teatini
Proc. IAHS, 372, 199–205, https://doi.org/10.5194/piahs-372-199-2015, https://doi.org/10.5194/piahs-372-199-2015, 2015
Short summary
Short summary
Eighty regular TerraSAR-X acquisitions over the 2008-2011 period significantly improve the subsidence monitoring at the Venice coastland. Settlements of 30-35 mm/yr have been detected at the three lagoon inlets in correspondence of the MoSE works. The Venice and Chioggia historical centers show local sinking bowls up to 10 mm/yr connected with the construction of new large buildings or restoration works. In the city of Venice, the mean subsidence of 1.1±1.0 mm/yr confirms its general stability.
I. Beck, R. Ludwig, M. Bernier, T. Strozzi, and J. Boike
Earth Surf. Dynam., 3, 409–421, https://doi.org/10.5194/esurf-3-409-2015, https://doi.org/10.5194/esurf-3-409-2015, 2015
M. Schäfer, F. Gillet-Chaulet, R. Gladstone, R. Pettersson, V. A. Pohjola, T. Strozzi, and T. Zwinger
The Cryosphere, 8, 1951–1973, https://doi.org/10.5194/tc-8-1951-2014, https://doi.org/10.5194/tc-8-1951-2014, 2014
R. Gladstone, M. Schäfer, T. Zwinger, Y. Gong, T. Strozzi, R. Mottram, F. Boberg, and J. C. Moore
The Cryosphere, 8, 1393–1405, https://doi.org/10.5194/tc-8-1393-2014, https://doi.org/10.5194/tc-8-1393-2014, 2014
Juditha Aga, Livia Piermattei, Luc Girod, Kristoffer Aalstad, Trond Eiken, Andreas Kääb, and Sebastian Westermann
Earth Surf. Dynam., 12, 1049–1070, https://doi.org/10.5194/esurf-12-1049-2024, https://doi.org/10.5194/esurf-12-1049-2024, 2024
Short summary
Short summary
Coastal rock cliffs on Svalbard are considered to be fairly stable; however, long-term trends in coastal-retreat rates remain unknown. This study examines changes in the coastline position along Brøggerhalvøya, Svalbard, using aerial images from 1970, 1990, 2010, and 2021. Our analysis shows that coastal-retreat rates accelerate during the period 2010–2021, which coincides with increasing storminess and retreating sea ice.
Barbara Widhalm, Annett Bartsch, Tazio Strozzi, Nina Jones, Artem Khomutov, Elena Babkina, Marina Leibman, Rustam Khairullin, Mathias Göckede, Helena Bergstedt, Clemens von Baeckmann, and Xaver Muri
EGUsphere, https://doi.org/10.5194/egusphere-2024-2356, https://doi.org/10.5194/egusphere-2024-2356, 2024
Short summary
Short summary
Mapping soil moisture in Arctic permafrost regions is crucial for various activities, but it is challenging with typical satellite methods due to the landscape's diversity. Seasonal freezing and thawing cause the ground to periodically rise and subside. Our research demonstrates that this seasonal ground settlement, measured with Sentinel-1 satellite data, is larger in areas with wetter soils. This method helps to monitor permafrost degradation.
Diego Cusicanqui, Pascal Lacroix, Xavier Bodin, Benjamin Aubrey Robson, Andreas Kääb, and Shelley MacDonell
EGUsphere, https://doi.org/10.5194/egusphere-2024-2393, https://doi.org/10.5194/egusphere-2024-2393, 2024
Short summary
Short summary
This study presents for the first time a robust methodological approach to detect and analyse rock glacier kinematics using 24 years of Landsat 7/8 imagery. Within a small region in the semi-arid andes, 382 movements were monitored showing an average velocity of 0.3 ± 0.07 m yr-1, with rock glaciers moving faster. We highlight the value of integrating optical imagery and radar interferometry supporting monitoring of rock glacier kinematics, using available medium-resolution optical imagery.
Livia Piermattei, Michael Zemp, Christian Sommer, Fanny Brun, Matthias H. Braun, Liss M. Andreassen, Joaquín M. C. Belart, Etienne Berthier, Atanu Bhattacharya, Laura Boehm Vock, Tobias Bolch, Amaury Dehecq, Inés Dussaillant, Daniel Falaschi, Caitlyn Florentine, Dana Floricioiu, Christian Ginzler, Gregoire Guillet, Romain Hugonnet, Matthias Huss, Andreas Kääb, Owen King, Christoph Klug, Friedrich Knuth, Lukas Krieger, Jeff La Frenierre, Robert McNabb, Christopher McNeil, Rainer Prinz, Louis Sass, Thorsten Seehaus, David Shean, Désirée Treichler, Anja Wendt, and Ruitang Yang
The Cryosphere, 18, 3195–3230, https://doi.org/10.5194/tc-18-3195-2024, https://doi.org/10.5194/tc-18-3195-2024, 2024
Short summary
Short summary
Satellites have made it possible to observe glacier elevation changes from all around the world. In the present study, we compared the results produced from two different types of satellite data between different research groups and against validation measurements from aeroplanes. We found a large spread between individual results but showed that the group ensemble can be used to reliably estimate glacier elevation changes and related errors from satellite data.
Aldo Bertone, Nina Jones, Volkmar Mair, Riccardo Scotti, Tazio Strozzi, and Francesco Brardinoni
The Cryosphere, 18, 2335–2356, https://doi.org/10.5194/tc-18-2335-2024, https://doi.org/10.5194/tc-18-2335-2024, 2024
Short summary
Short summary
Traditional inventories display high uncertainty in discriminating between intact (permafrost-bearing) and relict (devoid) rock glaciers (RGs). Integration of InSAR-based kinematics in South Tyrol affords uncertainty reduction and depicts a broad elevation belt of relict–intact coexistence. RG velocity and moving area (MA) cover increase linearly with elevation up to an inflection at 2600–2800 m a.s.l., which we regard as a signature of sporadic-to-discontinuous permafrost transition.
Andreas Kääb and Luc Girod
The Cryosphere, 17, 2533–2541, https://doi.org/10.5194/tc-17-2533-2023, https://doi.org/10.5194/tc-17-2533-2023, 2023
Short summary
Short summary
Following the detachment of the 130 × 106 m3 Sedongpu Glacier (south-eastern Tibet) in 2018, the Sedongpu Valley underwent massive large-volume landscape changes. An enormous volume of in total around 330 × 106 m3 was rapidly eroded, forming a new canyon of up to 300 m depth, 1 km width, and almost 4 km length. Such consequences of glacier change in mountains have so far not been considered at this magnitude and speed.
Sebastian Westermann, Thomas Ingeman-Nielsen, Johanna Scheer, Kristoffer Aalstad, Juditha Aga, Nitin Chaudhary, Bernd Etzelmüller, Simon Filhol, Andreas Kääb, Cas Renette, Louise Steffensen Schmidt, Thomas Vikhamar Schuler, Robin B. Zweigel, Léo Martin, Sarah Morard, Matan Ben-Asher, Michael Angelopoulos, Julia Boike, Brian Groenke, Frederieke Miesner, Jan Nitzbon, Paul Overduin, Simone M. Stuenzi, and Moritz Langer
Geosci. Model Dev., 16, 2607–2647, https://doi.org/10.5194/gmd-16-2607-2023, https://doi.org/10.5194/gmd-16-2607-2023, 2023
Short summary
Short summary
The CryoGrid community model is a new tool for simulating ground temperatures and the water and ice balance in cold regions. It is a modular design, which makes it possible to test different schemes to simulate, for example, permafrost ground in an efficient way. The model contains tools to simulate frozen and unfrozen ground, snow, glaciers, and other massive ice bodies, as well as water bodies.
Fuming Xie, Shiyin Liu, Yongpeng Gao, Yu Zhu, Tobias Bolch, Andreas Kääb, Shimei Duan, Wenfei Miao, Jianfang Kang, Yaonan Zhang, Xiran Pan, Caixia Qin, Kunpeng Wu, Miaomiao Qi, Xianhe Zhang, Ying Yi, Fengze Han, Xiaojun Yao, Qiao Liu, Xin Wang, Zongli Jiang, Donghui Shangguan, Yong Zhang, Richard Grünwald, Muhammad Adnan, Jyoti Karki, and Muhammad Saifullah
Earth Syst. Sci. Data, 15, 847–867, https://doi.org/10.5194/essd-15-847-2023, https://doi.org/10.5194/essd-15-847-2023, 2023
Short summary
Short summary
In this study, first we generated inventories which allowed us to systematically detect glacier change patterns in the Karakoram range. We found that, by the 2020s, there were approximately 10 500 glaciers in the Karakoram mountains covering an area of 22 510.73 km2, of which ~ 10.2 % is covered by debris. During the past 30 years (from 1990 to 2020), the total glacier cover area in Karakoram remained relatively stable, with a slight increase in area of 23.5 km2.
Alessandro Cicoira, Samuel Weber, Andreas Biri, Ben Buchli, Reynald Delaloye, Reto Da Forno, Isabelle Gärtner-Roer, Stephan Gruber, Tonio Gsell, Andreas Hasler, Roman Lim, Philippe Limpach, Raphael Mayoraz, Matthias Meyer, Jeannette Noetzli, Marcia Phillips, Eric Pointner, Hugo Raetzo, Cristian Scapozza, Tazio Strozzi, Lothar Thiele, Andreas Vieli, Daniel Vonder Mühll, Vanessa Wirz, and Jan Beutel
Earth Syst. Sci. Data, 14, 5061–5091, https://doi.org/10.5194/essd-14-5061-2022, https://doi.org/10.5194/essd-14-5061-2022, 2022
Short summary
Short summary
This paper documents a monitoring network of 54 positions, located on different periglacial landforms in the Swiss Alps: rock glaciers, landslides, and steep rock walls. The data serve basic research but also decision-making and mitigation of natural hazards. It is the largest dataset of its kind, comprising over 209 000 daily positions and additional weather data.
Maximillian Van Wyk de Vries, Shashank Bhushan, Mylène Jacquemart, César Deschamps-Berger, Etienne Berthier, Simon Gascoin, David E. Shean, Dan H. Shugar, and Andreas Kääb
Nat. Hazards Earth Syst. Sci., 22, 3309–3327, https://doi.org/10.5194/nhess-22-3309-2022, https://doi.org/10.5194/nhess-22-3309-2022, 2022
Short summary
Short summary
On 7 February 2021, a large rock–ice avalanche occurred in Chamoli, Indian Himalaya. The resulting debris flow swept down the nearby valley, leaving over 200 people dead or missing. We use a range of satellite datasets to investigate how the collapse area changed prior to collapse. We show that signs of instability were visible as early 5 years prior to collapse. However, it would likely not have been possible to predict the timing of the event from current satellite datasets.
Aldo Bertone, Chloé Barboux, Xavier Bodin, Tobias Bolch, Francesco Brardinoni, Rafael Caduff, Hanne H. Christiansen, Margaret M. Darrow, Reynald Delaloye, Bernd Etzelmüller, Ole Humlum, Christophe Lambiel, Karianne S. Lilleøren, Volkmar Mair, Gabriel Pellegrinon, Line Rouyet, Lucas Ruiz, and Tazio Strozzi
The Cryosphere, 16, 2769–2792, https://doi.org/10.5194/tc-16-2769-2022, https://doi.org/10.5194/tc-16-2769-2022, 2022
Short summary
Short summary
We present the guidelines developed by the IPA Action Group and within the ESA Permafrost CCI project to include InSAR-based kinematic information in rock glacier inventories. Nine operators applied these guidelines to 11 regions worldwide; more than 3600 rock glaciers are classified according to their kinematics. We test and demonstrate the feasibility of applying common rules to produce homogeneous kinematic inventories at global scale, useful for hydrological and climate change purposes.
Frank Paul, Livia Piermattei, Désirée Treichler, Lin Gilbert, Luc Girod, Andreas Kääb, Ludivine Libert, Thomas Nagler, Tazio Strozzi, and Jan Wuite
The Cryosphere, 16, 2505–2526, https://doi.org/10.5194/tc-16-2505-2022, https://doi.org/10.5194/tc-16-2505-2022, 2022
Short summary
Short summary
Glacier surges are widespread in the Karakoram and have been intensely studied using satellite data and DEMs. We use time series of such datasets to study three glacier surges in the same region of the Karakoram. We found strongly contrasting advance rates and flow velocities, maximum velocities of 30 m d−1, and a change in the surge mechanism during a surge. A sensor comparison revealed good agreement, but steep terrain and the two smaller glaciers caused limitations for some of them.
Bas Altena, Andreas Kääb, and Bert Wouters
The Cryosphere, 16, 2285–2300, https://doi.org/10.5194/tc-16-2285-2022, https://doi.org/10.5194/tc-16-2285-2022, 2022
Short summary
Short summary
Repeat overflights of satellites are used to estimate surface displacements. However, such products lack a simple error description for individual measurements, but variation in precision occurs, since the calculation is based on the similarity of texture. Fortunately, variation in precision manifests itself in the correlation peak, which is used for the displacement calculation. This spread is used to make a connection to measurement precision, which can be of great use for model inversion.
Isabelle Gärtner-Roer, Nina Brunner, Reynald Delaloye, Wilfried Haeberli, Andreas Kääb, and Patrick Thee
The Cryosphere, 16, 2083–2101, https://doi.org/10.5194/tc-16-2083-2022, https://doi.org/10.5194/tc-16-2083-2022, 2022
Short summary
Short summary
We intensely investigated the Gruben site in the Swiss Alps, where glaciers and permafrost landforms closely interact, to better understand cold-climate environments. By the interpretation of air photos from 5 decades, we describe long-term developments of the existing landforms. In combination with high-resolution positioning measurements and ground surface temperatures, we were also able to link these to short-term changes and describe different landform responses to climate forcing.
Tazio Strozzi, Andreas Wiesmann, Andreas Kääb, Thomas Schellenberger, and Frank Paul
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2022-44, https://doi.org/10.5194/essd-2022-44, 2022
Revised manuscript not accepted
Short summary
Short summary
Knowledge on surface velocity of glaciers and ice caps contributes to a better understanding of a wide range of processes related to glacier dynamics, mass change and response to climate. Based on the release of historical satellite radar data from various space agencies we compiled nearly complete mosaics of winter ice surface velocities for the 1990's over the Eastern Arctic. Compared to the present state, we observe a general increase of ice velocities along with a retreat of glacier fronts.
Paul Willem Leclercq, Andreas Kääb, and Bas Altena
The Cryosphere, 15, 4901–4907, https://doi.org/10.5194/tc-15-4901-2021, https://doi.org/10.5194/tc-15-4901-2021, 2021
Short summary
Short summary
In this study we present a novel method to detect glacier surge activity. Surges are relevant as they disturb the link between glacier change and climate, and studying surges can also increase understanding of glacier flow. We use variations in Sentinel-1 radar backscatter strength, calculated with the use of Google Earth Engine, to detect surge activity. In our case study for the year 2018–2019 we find 69 cases of surging glaciers globally. Many of these were not previously known to be surging.
Andreas Kääb, Mylène Jacquemart, Adrien Gilbert, Silvan Leinss, Luc Girod, Christian Huggel, Daniel Falaschi, Felipe Ugalde, Dmitry Petrakov, Sergey Chernomorets, Mikhail Dokukin, Frank Paul, Simon Gascoin, Etienne Berthier, and Jeffrey S. Kargel
The Cryosphere, 15, 1751–1785, https://doi.org/10.5194/tc-15-1751-2021, https://doi.org/10.5194/tc-15-1751-2021, 2021
Short summary
Short summary
Hardly recognized so far, giant catastrophic detachments of glaciers are a rare but great potential for loss of lives and massive damage in mountain regions. Several of the events compiled in our study involve volumes (up to 100 million m3 and more), avalanche speeds (up to 300 km/h), and reaches (tens of kilometres) that are hard to imagine. We show that current climate change is able to enhance associated hazards. For the first time, we elaborate a set of factors that could cause these events.
Andreas Kääb, Tazio Strozzi, Tobias Bolch, Rafael Caduff, Håkon Trefall, Markus Stoffel, and Alexander Kokarev
The Cryosphere, 15, 927–949, https://doi.org/10.5194/tc-15-927-2021, https://doi.org/10.5194/tc-15-927-2021, 2021
Short summary
Short summary
We present a map of rock glacier motion over parts of the northern Tien Shan and time series of surface speed for six of them over almost 70 years.
This is by far the most detailed investigation of this kind available for central Asia.
We detect a 2- to 4-fold increase in rock glacier motion between the 1950s and present, which we attribute to atmospheric warming.
Relative to the shrinking glaciers in the region, this implies increased importance of periglacial sediment transport.
Andreas Alexander, Jaroslav Obu, Thomas V. Schuler, Andreas Kääb, and Hanne H. Christiansen
The Cryosphere, 14, 4217–4231, https://doi.org/10.5194/tc-14-4217-2020, https://doi.org/10.5194/tc-14-4217-2020, 2020
Short summary
Short summary
In this study we present subglacial air, ice and sediment temperatures from within the basal drainage systems of two cold-based glaciers on Svalbard during late spring and the summer melt season. We put the data into the context of air temperature and rainfall at the glacier surface and show the importance of surface events on the subglacial thermal regime and erosion around basal drainage channels. Observed vertical erosion rates thereby reachup to 0.9 m d−1.
Tazio Strozzi, Dora Carreon-Freyre, and Urs Wegmüller
Proc. IAHS, 382, 179–182, https://doi.org/10.5194/piahs-382-179-2020, https://doi.org/10.5194/piahs-382-179-2020, 2020
Luigi Tosi, Cristina Da Lio, Sandra Donnici, Tazio Strozzi, and Pietro Teatini
Proc. IAHS, 382, 689–695, https://doi.org/10.5194/piahs-382-689-2020, https://doi.org/10.5194/piahs-382-689-2020, 2020
Short summary
Short summary
The Venice coastland forms the major low-lying area in Italy and encompasses a variety of environments, such as farmlands, estuaries, deltas, lagoons and urbanized areas. Since most of the territory lies at a ground elevation below or slightly above the mean sea-level, also a few mm/yr of land subsidence can seriously impacts on the coastal system. In this study, we present an analysis of the vulnerability to relative sea-level rise (RSLR) considering an uneven land subsidence distribution.
Andreas Alexander, Maarja Kruusmaa, Jeffrey A. Tuhtan, Andrew J. Hodson, Thomas V. Schuler, and Andreas Kääb
The Cryosphere, 14, 1009–1023, https://doi.org/10.5194/tc-14-1009-2020, https://doi.org/10.5194/tc-14-1009-2020, 2020
Short summary
Short summary
This work shows the potential of pressure and inertia sensing drifters to measure flow parameters along glacial channels. The technology allows us to record the spatial distribution of water pressures, as well as an estimation of the flow velocity along the flow path in the channels. The measurements show a high repeatability and the potential to identify channel morphology from sensor readings.
Jaroslav Obu, Sebastian Westermann, Gonçalo Vieira, Andrey Abramov, Megan Ruby Balks, Annett Bartsch, Filip Hrbáček, Andreas Kääb, and Miguel Ramos
The Cryosphere, 14, 497–519, https://doi.org/10.5194/tc-14-497-2020, https://doi.org/10.5194/tc-14-497-2020, 2020
Short summary
Short summary
Little is known about permafrost in the Antarctic outside of the few research stations. We used a simple equilibrium permafrost model to estimate permafrost temperatures in the whole Antarctic. The lowest permafrost temperature on Earth is −36 °C in the Queen Elizabeth Range in the Transantarctic Mountains. Temperatures are commonly between −23 and −18 °C in mountainous areas rising above the Antarctic Ice Sheet, between −14 and −8 °C in coastal areas, and up to 0 °C on the Antarctic Peninsula.
Désirée Treichler, Andreas Kääb, Nadine Salzmann, and Chong-Yu Xu
The Cryosphere, 13, 2977–3005, https://doi.org/10.5194/tc-13-2977-2019, https://doi.org/10.5194/tc-13-2977-2019, 2019
Short summary
Short summary
Glacier growth such as that found on the Tibetan Plateau (TP) is counterintuitive in a warming world. Climate models and meteorological data are conflicting about the reasons for this glacier anomaly. We quantify the glacier changes in High Mountain Asia using satellite laser altimetry as well as the growth of over 1300 inland lakes on the TP. Our study suggests that increased summer precipitation is likely the largest contributor to the recently observed increases in glacier and lake masses.
Andreas Kääb, Bas Altena, and Joseph Mascaro
Hydrol. Earth Syst. Sci., 23, 4233–4247, https://doi.org/10.5194/hess-23-4233-2019, https://doi.org/10.5194/hess-23-4233-2019, 2019
Short summary
Short summary
Knowledge of water surface velocities in rivers is useful for understanding a wide range of processes and systems, but is difficult to measure over large reaches. Here, we present a novel method to exploit near-simultaneous imagery produced by the Planet cubesat constellation to track river ice floes and estimate water surface velocities. We demonstrate the method for a 60 km long reach of the Amur River and a 200 km long reach of the Yukon River.
B. Altena, O. N. Haga, C. Nuth, and A. Kääb
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLII-2-W13, 1723–1727, https://doi.org/10.5194/isprs-archives-XLII-2-W13-1723-2019, https://doi.org/10.5194/isprs-archives-XLII-2-W13-1723-2019, 2019
Cristian Scapozza, Christian Ambrosi, Massimiliano Cannata, and Tazio Strozzi
Geogr. Helv., 74, 125–139, https://doi.org/10.5194/gh-74-125-2019, https://doi.org/10.5194/gh-74-125-2019, 2019
Short summary
Short summary
A glacial lake outburst flood hazard assessment by satellite Earth observation and numerical modelling was done for the lakes linked to the Thangothang Chhu glacier, Chomolhari area (Bhutan), combining detailed geomorphological mapping, landslide and rock glacier inventories, as well as surface displacements quantified by satellite InSAR. Outburst scenario modelling revealed that only a flood wave can have an impact on the two human settlements located downslope of the glacier.
Daniel Falaschi, Andreas Kääb, Frank Paul, Takeo Tadono, Juan Antonio Rivera, and Luis Eduardo Lenzano
The Cryosphere, 13, 997–1004, https://doi.org/10.5194/tc-13-997-2019, https://doi.org/10.5194/tc-13-997-2019, 2019
Short summary
Short summary
In March 2007, the Leñas Glacier in the Central Andes of Argentina collapsed and released an ice avalanche that travelled a distance of 2 km. We analysed aerial photos, satellite images and field evidence to investigate the evolution of the glacier from the 1950s through the present day. A clear potential trigger of the collapse could not be identified from available meteorological and seismic data, nor could a significant change in glacier geometry leading to glacier instability be detected.
Robert McNabb, Christopher Nuth, Andreas Kääb, and Luc Girod
The Cryosphere, 13, 895–910, https://doi.org/10.5194/tc-13-895-2019, https://doi.org/10.5194/tc-13-895-2019, 2019
Short summary
Short summary
Estimating glacier changes involves measuring elevation changes, often using elevation models derived from satellites. Many elevation models have data gaps (voids), which affect estimates of glacier change. We compare 11 methods for interpolating voids, finding that some methods bias estimates of glacier change by up to 20 %, though most methods have a smaller effect. Some methods produce reliable results even with large void areas, suggesting that noisy elevation data are still useful.
Bas Altena, Ted Scambos, Mark Fahnestock, and Andreas Kääb
The Cryosphere, 13, 795–814, https://doi.org/10.5194/tc-13-795-2019, https://doi.org/10.5194/tc-13-795-2019, 2019
Short summary
Short summary
Many glaciers in southern Alaska and the Yukon experience changes in flow speed, which occur in episodes or sporadically. These flow changes can be measured with satellites, but the resulting raw velocity products are messy. Thus in this study we developed an automatic method to produce a synthesized velocity product over a large glacier region of roughly 600 km by 200 km. Velocities are at a monthly resolution and at 300 m resolution, making all kinds of glacier dynamics observable.
Luc Girod, Niels Ivar Nielsen, Frédérique Couderette, Christopher Nuth, and Andreas Kääb
Geosci. Instrum. Method. Data Syst., 7, 277–288, https://doi.org/10.5194/gi-7-277-2018, https://doi.org/10.5194/gi-7-277-2018, 2018
Short summary
Short summary
Historical surveys performed through the use of aerial photography gave us the first maps of the Arctic. Nearly a century later, a renewed interest in studying the Arctic is rising from the need to understand and quantify climate change. It is therefore time to dig up the archives and extract the maximum of information from the images using the most modern methods. In this study, we show that the aerial survey of Svalbard in 1936–38 provides us with valuable data on the archipelago's glaciers.
Nico Mölg, Tobias Bolch, Philipp Rastner, Tazio Strozzi, and Frank Paul
Earth Syst. Sci. Data, 10, 1807–1827, https://doi.org/10.5194/essd-10-1807-2018, https://doi.org/10.5194/essd-10-1807-2018, 2018
Short summary
Short summary
Knowledge about the size and location of glaciers is essential to understand impacts of climatic changes on the natural environment. Therefore, we have produced an inventory of all glaciers in some of the largest glacierized mountain regions worldwide. Many large glaciers are covered by a rock (debris) layer, which also changes their reaction to climatic changes. Thus, we have also mapped this debris layer for all glaciers. We have mapped almost 28000 glaciers covering ~35000 km2.
Adrien Gilbert, Silvan Leinss, Jeffrey Kargel, Andreas Kääb, Simon Gascoin, Gregory Leonard, Etienne Berthier, Alina Karki, and Tandong Yao
The Cryosphere, 12, 2883–2900, https://doi.org/10.5194/tc-12-2883-2018, https://doi.org/10.5194/tc-12-2883-2018, 2018
Short summary
Short summary
In Tibet, two glaciers suddenly collapsed in summer 2016 and produced two gigantic ice avalanches, killing nine people. This kind of phenomenon is extremely rare. By combining a detailed modelling study and high-resolution satellite observations, we show that the event was triggered by an increasing meltwater supply in the fine-grained material underneath the two glaciers. Contrary to what is often thought, this event is not linked to a change in the thermal condition at the glacier base.
Martina Barandun, Matthias Huss, Ryskul Usubaliev, Erlan Azisov, Etienne Berthier, Andreas Kääb, Tobias Bolch, and Martin Hoelzle
The Cryosphere, 12, 1899–1919, https://doi.org/10.5194/tc-12-1899-2018, https://doi.org/10.5194/tc-12-1899-2018, 2018
Short summary
Short summary
In this study, we used three independent methods (in situ measurements, comparison of digital elevation models and modelling) to reconstruct the mass change from 2000 to 2016 for three glaciers in the Tien Shan and Pamir. Snow lines observed on remote sensing images were used to improve conventional modelling by constraining a mass balance model. As a result, glacier mass changes for unmeasured years and glaciers can be better assessed. Substantial mass loss was confirmed for the three glaciers.
Yongmei Gong, Thomas Zwinger, Jan Åström, Bas Altena, Thomas Schellenberger, Rupert Gladstone, and John C. Moore
The Cryosphere, 12, 1563–1577, https://doi.org/10.5194/tc-12-1563-2018, https://doi.org/10.5194/tc-12-1563-2018, 2018
Short summary
Short summary
In this study we apply a discrete element model capable of simulating ice fracturing. A microscopic-scale discrete process is applied in addition to a continuum ice dynamics model to investigate the mechanisms facilitated by basal meltwater production, surface meltwater and ice crack opening, for the surge in Basin 3, Austfonna ice cap. The discrete element model is used to locate the ice cracks that can penetrate though the full thickness of the glacier and deliver surface water to the bed.
Chiyuki Narama, Mirlan Daiyrov, Murataly Duishonakunov, Takeo Tadono, Hayato Sato, Andreas Kääb, Jinro Ukita, and Kanatbek Abdrakhmatov
Nat. Hazards Earth Syst. Sci., 18, 983–995, https://doi.org/10.5194/nhess-18-983-2018, https://doi.org/10.5194/nhess-18-983-2018, 2018
Short summary
Short summary
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. Due to their subsurface outlet, we refer to these short-lived glacial lakes as being of the
tunnel-type, a type that drastically grows and drains over a few months.
Solveig H. Winsvold, Andreas Kääb, Christopher Nuth, Liss M. Andreassen, Ward J. J. van Pelt, and Thomas Schellenberger
The Cryosphere, 12, 867–890, https://doi.org/10.5194/tc-12-867-2018, https://doi.org/10.5194/tc-12-867-2018, 2018
B. Altena, A. Mousivand, J. Mascaro, and A. Kääb
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLII-3-W3, 7–11, https://doi.org/10.5194/isprs-archives-XLII-3-W3-7-2017, https://doi.org/10.5194/isprs-archives-XLII-3-W3-7-2017, 2017
Andreas Kääb, Bas Altena, and Joseph Mascaro
Nat. Hazards Earth Syst. Sci., 17, 627–639, https://doi.org/10.5194/nhess-17-627-2017, https://doi.org/10.5194/nhess-17-627-2017, 2017
Short summary
Short summary
We evaluate for the first time a new class of optical satellite images for measuring Earth surface displacements due to earthquakes – images from cubesats. The PlanetScope cubesats used in this study are 10 cm × 10 cm × 30 cm small and standardized satellites. Around 120 of these cubesats orbit around Earth and are about to provide daily 2–4 m resolution images of the entire land surface of the Earth.
Luc Girod, Christopher Nuth, Andreas Kääb, Bernd Etzelmüller, and Jack Kohler
The Cryosphere, 11, 827–840, https://doi.org/10.5194/tc-11-827-2017, https://doi.org/10.5194/tc-11-827-2017, 2017
Short summary
Short summary
While gathering data on a changing environment is often a costly and complicated endeavour, it is also the backbone of all research. What if one could measure elevation change by just strapping a camera and a hiking GPS under an helicopter or a small airplane used for transportation and gather data on the ground bellow the flight path? In this article, we present a way to do exactly that and show an example survey where it helped compute the volume of ice lost by a glacier in Svalbard.
Thomas Schellenberger, Thorben Dunse, Andreas Kääb, Thomas Vikhamar Schuler, Jon Ove Hagen, and Carleen H. Reijmer
The Cryosphere Discuss., https://doi.org/10.5194/tc-2017-5, https://doi.org/10.5194/tc-2017-5, 2017
Preprint withdrawn
Short summary
Short summary
Basin-3, NE-Svalbard, was still surging with 10 m d-1 in July 2016. After a speed peak of 18.8 m d-1 in Dec 2012/Jan 2013, speed-ups are overlying the fast flow every summer. The glacier is massively calving icebergs (5.2 Gt yr-1 ~ 2 L drinking water for every human being daily!) which in the same order of magnitude as all other Svalbard glaciers together.
Since autumn 2015 also Basin-2 is surging with maximum velocities of 8.7 m d-1, an advance of more than 2 km and a mass loss of 0.7 Gt yr-1.
Désirée Treichler and Andreas Kääb
The Cryosphere, 10, 2129–2146, https://doi.org/10.5194/tc-10-2129-2016, https://doi.org/10.5194/tc-10-2129-2016, 2016
Short summary
Short summary
Satellite data are often the only source of information on mountain glaciers. We show that data from ICESat laser satellite can accurately reflect glacier volume development in 2003–2008, also for individual years. We detect a spatially varying elevation bias in commonly used data sets, and provide a correction that strongly increases the significance of the glacier change estimates – a crucial driver of climate-induced meltwater changes that directly affect the life of lowland populations.
T. Schellenberger, T. Dunse, A. Kääb, J. Kohler, and C. H. Reijmer
The Cryosphere, 9, 2339–2355, https://doi.org/10.5194/tc-9-2339-2015, https://doi.org/10.5194/tc-9-2339-2015, 2015
Short summary
Short summary
Kronebreen and Kongsbreen are among the fastest flowing glaciers on Svalbard, and surface speeds reached up to 3.2m d-1 at Kronebreen in summer 2013 and 2.7m d-1 at Kongsbreen in late autumn 2012 as retrieved from SAR satellite data. Both glaciers retreated significantly during the observation period, Kongsbreen up to 1800m or 2.5km2 and Kronebreen up to 850m or 2.8km2. Both glaciers are important contributors to the total dynamic mass loss from the Svalbard archipelago.
L. Tosi, T. Strozzi, C. Da Lio, and P. Teatini
Proc. IAHS, 372, 199–205, https://doi.org/10.5194/piahs-372-199-2015, https://doi.org/10.5194/piahs-372-199-2015, 2015
Short summary
Short summary
Eighty regular TerraSAR-X acquisitions over the 2008-2011 period significantly improve the subsidence monitoring at the Venice coastland. Settlements of 30-35 mm/yr have been detected at the three lagoon inlets in correspondence of the MoSE works. The Venice and Chioggia historical centers show local sinking bowls up to 10 mm/yr connected with the construction of new large buildings or restoration works. In the city of Venice, the mean subsidence of 1.1±1.0 mm/yr confirms its general stability.
I. Beck, R. Ludwig, M. Bernier, T. Strozzi, and J. Boike
Earth Surf. Dynam., 3, 409–421, https://doi.org/10.5194/esurf-3-409-2015, https://doi.org/10.5194/esurf-3-409-2015, 2015
A. Kääb, D. Treichler, C. Nuth, and E. Berthier
The Cryosphere, 9, 557–564, https://doi.org/10.5194/tc-9-557-2015, https://doi.org/10.5194/tc-9-557-2015, 2015
Short summary
Short summary
Based on satellite laser altimetry over the Pamir--Karakoram Himalaya we detect strongest elevation losses over east Nyainqentanglha Shan and Spiti--Lahaul but slight elevation gains over west Kunlun Shan rather than over Karakoram. The current sea-level contribution of Pamir--Karakoram Himalaya glaciers is about 10% of the total global contribution of glaciers outside the ice sheets. We also improve estimates of glacier imbalance contribution to river discharge in the Himalayas.
T. Dunse, T. Schellenberger, J. O. Hagen, A. Kääb, T. V. Schuler, and C. H. Reijmer
The Cryosphere, 9, 197–215, https://doi.org/10.5194/tc-9-197-2015, https://doi.org/10.5194/tc-9-197-2015, 2015
M. Schäfer, F. Gillet-Chaulet, R. Gladstone, R. Pettersson, V. A. Pohjola, T. Strozzi, and T. Zwinger
The Cryosphere, 8, 1951–1973, https://doi.org/10.5194/tc-8-1951-2014, https://doi.org/10.5194/tc-8-1951-2014, 2014
R. Gladstone, M. Schäfer, T. Zwinger, Y. Gong, T. Strozzi, R. Mottram, F. Boberg, and J. C. Moore
The Cryosphere, 8, 1393–1405, https://doi.org/10.5194/tc-8-1393-2014, https://doi.org/10.5194/tc-8-1393-2014, 2014
A. Kääb, L. Girod, and I. Berthling
The Cryosphere, 8, 1041–1056, https://doi.org/10.5194/tc-8-1041-2014, https://doi.org/10.5194/tc-8-1041-2014, 2014
A. Kääb, M. Lamare, and M. Abrams
Hydrol. Earth Syst. Sci., 17, 4671–4683, https://doi.org/10.5194/hess-17-4671-2013, https://doi.org/10.5194/hess-17-4671-2013, 2013
C. Nuth, J. Kohler, M. König, A. von Deschwanden, J. O. Hagen, A. Kääb, G. Moholdt, and R. Pettersson
The Cryosphere, 7, 1603–1621, https://doi.org/10.5194/tc-7-1603-2013, https://doi.org/10.5194/tc-7-1603-2013, 2013
J. Gardelle, E. Berthier, Y. Arnaud, and A. Kääb
The Cryosphere, 7, 1263–1286, https://doi.org/10.5194/tc-7-1263-2013, https://doi.org/10.5194/tc-7-1263-2013, 2013
Related subject area
Glaciers
Linking Glacier Retreat with Climate Change on the Tibetan Plateau through Satellite Remote Sensing
A quasi-one-dimensional ice mélange flow model based on continuum descriptions of granular materials
Brief communication: Rapid acceleration of the Brunt Ice Shelf after calving of iceberg A-81
Modelling the historical and future evolution of six ice masses in the Tien Shan, Central Asia, using a 3D ice-flow model
Thinning and surface mass balance patterns of two neighbouring debris-covered glaciers in the southeastern Tibetan Plateau
Everest South Col Glacier did not thin during the period 1984–2017
Meltwater runoff and glacier mass balance in the high Arctic: 1991–2022 simulations for Svalbard
Impact of tides on calving patterns at Kronebreen, Svalbard – insights from three-dimensional ice dynamical modelling
Brief communication: Glacier mapping and change estimation using very high-resolution declassified Hexagon KH-9 panoramic stereo imagery (1971–1984)
Brief communication: Estimating the ice thickness of the Müller Ice Cap to support selection of a drill site
Glacier geometry and flow speed determine how Arctic marine-terminating glaciers respond to lubricated beds
A regionally resolved inventory of High Mountain Asia surge-type glaciers, derived from a multi-factor remote sensing approach
Geometric controls of tidewater glacier dynamics
Towards ice-thickness inversion: an evaluation of global digital elevation models (DEMs) in the glacierized Tibetan Plateau
Record summer rains in 2019 led to massive loss of surface and cave ice in SE Europe
Evolution of the firn pack of Kaskawulsh Glacier, Yukon: meltwater effects, densification, and the development of a perennial firn aquifer
A simple parametrization of mélange buttressing for calving glaciers
Full crystallographic orientation (c and a axes) of warm, coarse-grained ice in a shear-dominated setting: a case study, Storglaciären, Sweden
A decade of variability on Jakobshavn Isbræ: ocean temperatures pace speed through influence on mélange rigidity
Contribution of calving to frontal ablation quantified from seismic and hydroacoustic observations calibrated with lidar volume measurements
Brief communication: Updated GAMDAM glacier inventory over high-mountain Asia
Ice cliff contribution to the tongue-wide ablation of Changri Nup Glacier, Nepal, central Himalaya
Effects of undercutting and sliding on calving: a global approach applied to Kronebreen, Svalbard
Surface lowering of the debris-covered area of Kanchenjunga Glacier in the eastern Nepal Himalaya since 1975, as revealed by Hexagon KH-9 and ALOS satellite observations
Initiation of a major calving event on the Bowdoin Glacier captured by UAV photogrammetry
Calving localization at Helheim Glacier using multiple local seismic stations
Spatial variability in mass loss of glaciers in the Everest region, central Himalayas, between 2000 and 2015
Diagnosing the decline in climatic mass balance of glaciers in Svalbard over 1957–2014
Recent changes in area and thickness of Torngat Mountain glaciers (northern Labrador, Canada)
Brief communication: Thinning of debris-covered and debris-free glaciers in a warming climate
Concentration, sources and light absorption characteristics of dissolved organic carbon on a medium-sized valley glacier, northern Tibetan Plateau
3-D surface properties of glacier penitentes over an ablation season, measured using a Microsoft Xbox Kinect
Rapid glacial retreat on the Kamchatka Peninsula during the early 21st century
Reduced melt on debris-covered glaciers: investigations from Changri Nup Glacier, Nepal
Basal buoyancy and fast-moving glaciers: in defense of analytic force balance
The climatic mass balance of Svalbard glaciers: a 10-year simulation with a coupled atmosphere–glacier mass balance model
Correction of broadband snow albedo measurements affected by unknown slope and sensor tilts
Ablation from calving and surface melt at lake-terminating Bridge Glacier, British Columbia, 1984–2013
Brief Communication: Global reconstructions of glacier mass change during the 20th century are consistent
Surface speed and frontal ablation of Kronebreen and Kongsbreen, NW Svalbard, from SAR offset tracking
Improving semi-automated glacier mapping with a multi-method approach: applications in central Asia
Area, elevation and mass changes of the two southernmost ice caps of the Canadian Arctic Archipelago between 1952 and 2014
Modelling annual mass balances of eight Scandinavian glaciers using statistical models
Winter speed-up of quiescent surge-type glaciers in Yukon, Canada
Modelling glacier change in the Everest region, Nepal Himalaya
The GAMDAM glacier inventory: a quality-controlled inventory of Asian glaciers
Climate regime of Asian glaciers revealed by GAMDAM glacier inventory
A model study of Abrahamsenbreen, a surging glacier in northern Spitsbergen
Mass changes of Southern and Northern Inylchek Glacier, Central Tian Shan, Kyrgyzstan, during ∼1975 and 2007 derived from remote sensing data
Changes in the southeast Vatnajökull ice cap, Iceland, between ~ 1890 and 2010
Fumeng Zhao, Wenping Gong, Silvia Bianchini, and Zhongkang Yang
EGUsphere, https://doi.org/10.5194/egusphere-2024-1083, https://doi.org/10.5194/egusphere-2024-1083, 2024
Short summary
Short summary
Glacier retreat patterns and climatic drivers on the Tibetan Plateau are uncertain at finer resolutions. This study introduces a new glacier mapping method covering 1988 to 2022, with downscaled air temperature and precipitation data. It quantifies the impacts of annual and seasonal temperature and precipitation on retreat. Results show rapid and varied retreat, with annual temperature influencing retreat in the west and spring precipitation in the northwest.
Jason M. Amundson, Alexander A. Robel, Justin C. Burton, and Kavinda Nissanka
EGUsphere, https://doi.org/10.5194/egusphere-2024-297, https://doi.org/10.5194/egusphere-2024-297, 2024
Short summary
Short summary
Some fjords contain dense packs of icebergs referred to as ice mélange. Ice mélange can affect the stability of marine-terminating glaciers by resisting the calving of new icebergs and by modifying fjord currents and water properties. We have developed the first numerical model of ice mélange that captures its granular nature and that is suitable for long time-scale simulations. The model is capable of explaining why some glaciers are more strongly influenced by ice mélange than others.
Oliver J. Marsh, Adrian J. Luckman, and Dominic A. Hodgson
The Cryosphere, 18, 705–710, https://doi.org/10.5194/tc-18-705-2024, https://doi.org/10.5194/tc-18-705-2024, 2024
Short summary
Short summary
The Brunt Ice Shelf has accelerated rapidly after calving an iceberg in January 2023. A decade of GPS data show that the rate of acceleration in August 2023 was 30 times higher than before calving, and velocity has doubled in 6 months. Satellite velocity maps show the extent of the change. The acceleration is due to loss of contact between the ice shelf and a pinning point known as the McDonald Ice Rumples. The observations highlight how iceberg calving can directly impact ice shelves.
Lander Van Tricht and Philippe Huybrechts
The Cryosphere, 17, 4463–4485, https://doi.org/10.5194/tc-17-4463-2023, https://doi.org/10.5194/tc-17-4463-2023, 2023
Short summary
Short summary
We modelled the historical and future evolution of six ice masses in the Tien Shan, Central Asia, with a 3D ice-flow model under the newest climate scenarios. We show that in all scenarios the ice masses retreat significantly but with large differences. It is highlighted that, because the main precipitation occurs in spring and summer, the ice masses respond to climate change with an accelerating retreat. In all scenarios, the total runoff peaks before 2050, with a (drastic) decrease afterwards.
Chuanxi Zhao, Wei Yang, Evan Miles, Matthew Westoby, Marin Kneib, Yongjie Wang, Zhen He, and Francesca Pellicciotti
The Cryosphere, 17, 3895–3913, https://doi.org/10.5194/tc-17-3895-2023, https://doi.org/10.5194/tc-17-3895-2023, 2023
Short summary
Short summary
This paper quantifies the thinning and surface mass balance of two neighbouring debris-covered glaciers in the southeastern Tibetan Plateau during different seasons, based on high spatio-temporal resolution UAV-derived (unpiloted aerial
vehicle) data and in situ observations. Through a comparison approach and high-precision results, we identify that the glacier dynamic and debris thickness are strongly related to the future fate of the debris-covered glaciers in this region.
Fanny Brun, Owen King, Marion Réveillet, Charles Amory, Anton Planchot, Etienne Berthier, Amaury Dehecq, Tobias Bolch, Kévin Fourteau, Julien Brondex, Marie Dumont, Christoph Mayer, Silvan Leinss, Romain Hugonnet, and Patrick Wagnon
The Cryosphere, 17, 3251–3268, https://doi.org/10.5194/tc-17-3251-2023, https://doi.org/10.5194/tc-17-3251-2023, 2023
Short summary
Short summary
The South Col Glacier is a small body of ice and snow located on the southern ridge of Mt. Everest. A recent study proposed that South Col Glacier is rapidly losing mass. In this study, we examined the glacier thickness change for the period 1984–2017 and found no thickness change. To reconcile these results, we investigate wind erosion and surface energy and mass balance and find that melt is unlikely a dominant process, contrary to previous findings.
Louise Steffensen Schmidt, Thomas Vikhamar Schuler, Erin Emily Thomas, and Sebastian Westermann
The Cryosphere, 17, 2941–2963, https://doi.org/10.5194/tc-17-2941-2023, https://doi.org/10.5194/tc-17-2941-2023, 2023
Short summary
Short summary
Here, we present high-resolution simulations of glacier mass balance (the gain and loss of ice over a year) and runoff on Svalbard from 1991–2022, one of the fastest warming regions in the Arctic. The simulations are created using the CryoGrid community model. We find a small overall loss of mass over the simulation period of −0.08 m yr−1 but with no statistically significant trend. The average runoff was found to be 41 Gt yr−1, with a significant increasing trend of 6.3 Gt per decade.
Felicity A. Holmes, Eef van Dongen, Riko Noormets, Michał Pętlicki, and Nina Kirchner
The Cryosphere, 17, 1853–1872, https://doi.org/10.5194/tc-17-1853-2023, https://doi.org/10.5194/tc-17-1853-2023, 2023
Short summary
Short summary
Glaciers which end in bodies of water can lose mass through melting below the waterline, as well as by the breaking off of icebergs. We use a numerical model to simulate the breaking off of icebergs at Kronebreen, a glacier in Svalbard, and find that both melting below the waterline and tides are important for iceberg production. In addition, we compare the modelled glacier front to observations and show that melting below the waterline can lead to undercuts of up to around 25 m.
Sajid Ghuffar, Owen King, Grégoire Guillet, Ewelina Rupnik, and Tobias Bolch
The Cryosphere, 17, 1299–1306, https://doi.org/10.5194/tc-17-1299-2023, https://doi.org/10.5194/tc-17-1299-2023, 2023
Short summary
Short summary
The panoramic cameras (PCs) on board Hexagon KH-9 satellite missions from 1971–1984 captured very high-resolution stereo imagery with up to 60 cm spatial resolution. This study explores the potential of this imagery for glacier mapping and change estimation. The high resolution of KH-9PC leads to higher-quality DEMs which better resolve the accumulation region of glaciers in comparison to the KH-9 mapping camera, and KH-9PC imagery can be useful in several Earth observation applications.
Ann-Sofie Priergaard Zinck and Aslak Grinsted
The Cryosphere, 16, 1399–1407, https://doi.org/10.5194/tc-16-1399-2022, https://doi.org/10.5194/tc-16-1399-2022, 2022
Short summary
Short summary
The Müller Ice Cap will soon set the scene for a new drilling project. To obtain an ice core with stratified layers and a good time resolution, thickness estimates are necessary for the planning. Here we present a new and fast method of estimating ice thicknesses from sparse data and compare it to an existing ice flow model. We find that the new semi-empirical method is insensitive to mass balance, is computationally fast, and provides good fits when compared to radar measurements.
Whyjay Zheng
The Cryosphere, 16, 1431–1445, https://doi.org/10.5194/tc-16-1431-2022, https://doi.org/10.5194/tc-16-1431-2022, 2022
Short summary
Short summary
A glacier can speed up when surface water reaches the glacier's bottom via crevasses and reduces sliding friction. This paper builds up a physical model and finds that thick and fast-flowing glaciers are sensitive to this friction disruption. The data from Greenland and Austfonna (Svalbard) glaciers over 20 years support the model prediction. To estimate the projected sea-level rise better, these sensitive glaciers should be frequently monitored for potential future instabilities.
Gregoire Guillet, Owen King, Mingyang Lv, Sajid Ghuffar, Douglas Benn, Duncan Quincey, and Tobias Bolch
The Cryosphere, 16, 603–623, https://doi.org/10.5194/tc-16-603-2022, https://doi.org/10.5194/tc-16-603-2022, 2022
Short summary
Short summary
Surging glaciers show cyclical changes in flow behavior – between slow and fast flow – and can have drastic impacts on settlements in their vicinity.
One of the clusters of surging glaciers worldwide is High Mountain Asia (HMA).
We present an inventory of surging glaciers in HMA, identified from satellite imagery. We show that the number of surging glaciers was underestimated and that they represent 20 % of the area covered by glaciers in HMA, before discussing new physics for glacier surges.
Thomas Frank, Henning Åkesson, Basile de Fleurian, Mathieu Morlighem, and Kerim H. Nisancioglu
The Cryosphere, 16, 581–601, https://doi.org/10.5194/tc-16-581-2022, https://doi.org/10.5194/tc-16-581-2022, 2022
Short summary
Short summary
The shape of a fjord can promote or inhibit glacier retreat in response to climate change. We conduct experiments with a synthetic setup under idealized conditions in a numerical model to study and quantify the processes involved. We find that friction between ice and fjord is the most important factor and that it is possible to directly link ice discharge and grounding line retreat to fjord topography in a quantitative way.
Wenfeng Chen, Tandong Yao, Guoqing Zhang, Fei Li, Guoxiong Zheng, Yushan Zhou, and Fenglin Xu
The Cryosphere, 16, 197–218, https://doi.org/10.5194/tc-16-197-2022, https://doi.org/10.5194/tc-16-197-2022, 2022
Short summary
Short summary
A digital elevation model (DEM) is a prerequisite for estimating regional glacier thickness. Our study first compared six widely used global DEMs over the glacierized Tibetan Plateau by using ICESat-2 (Ice, Cloud and land Elevation Satellite) laser altimetry data. Our results show that NASADEM had the best accuracy. We conclude that NASADEM would be the best choice for ice-thickness estimation over the Tibetan Plateau through an intercomparison of four ice-thickness inversion models.
Aurel Perşoiu, Nenad Buzjak, Alexandru Onaca, Christos Pennos, Yorgos Sotiriadis, Monica Ionita, Stavros Zachariadis, Michael Styllas, Jure Kosutnik, Alexandru Hegyi, and Valerija Butorac
The Cryosphere, 15, 2383–2399, https://doi.org/10.5194/tc-15-2383-2021, https://doi.org/10.5194/tc-15-2383-2021, 2021
Short summary
Short summary
Extreme precipitation events in summer 2019 led to catastrophic loss of cave and surface ice in SE Europe at levels unprecedented during the last century. The projected continuous warming and increase in precipitation extremes could pose an additional threat to glaciers in southern Europe, resulting in a potentially ice-free SE Europe by the middle of the next decade (2035 CE).
Naomi E. Ochwat, Shawn J. Marshall, Brian J. Moorman, Alison S. Criscitiello, and Luke Copland
The Cryosphere, 15, 2021–2040, https://doi.org/10.5194/tc-15-2021-2021, https://doi.org/10.5194/tc-15-2021-2021, 2021
Short summary
Short summary
In May 2018 we drilled into Kaskawulsh Glacier to study how it is being affected by climate warming and used models to investigate the evolution of the firn since the 1960s. We found that the accumulation zone has experienced increased melting that has refrozen as ice layers and has formed a perennial firn aquifer. These results better inform climate-induced changes on northern glaciers and variables to take into account when estimating glacier mass change using remote-sensing methods.
Tanja Schlemm and Anders Levermann
The Cryosphere, 15, 531–545, https://doi.org/10.5194/tc-15-531-2021, https://doi.org/10.5194/tc-15-531-2021, 2021
Short summary
Short summary
Ice loss from Greenland and Antarctica is often cloaked by a mélange of icebergs and sea ice. Here we provide a simple method to parametrize the resulting back stress on the ice flow for large-scale projection models.
Morgan E. Monz, Peter J. Hudleston, David J. Prior, Zachary Michels, Sheng Fan, Marianne Negrini, Pat J. Langhorne, and Chao Qi
The Cryosphere, 15, 303–324, https://doi.org/10.5194/tc-15-303-2021, https://doi.org/10.5194/tc-15-303-2021, 2021
Short summary
Short summary
We present full crystallographic orientations of warm, coarse-grained ice deformed in a shear setting, enabling better characterization of how crystals in glacial ice preferentially align as ice flows. A commonly noted c-axis pattern, with several favored orientations, may result from bias due to overcounting large crystals with complex 3D shapes. A new sample preparation method effectively increases the sample size and reduces bias, resulting in a simpler pattern consistent with the ice flow.
Ian Joughin, David E. Shean, Benjamin E. Smith, and Dana Floricioiu
The Cryosphere, 14, 211–227, https://doi.org/10.5194/tc-14-211-2020, https://doi.org/10.5194/tc-14-211-2020, 2020
Short summary
Short summary
Jakobshavn Isbræ, considered to be Greenland's fastest glacier, has varied its speed and thinned dramatically since the 1990s. Here we examine the glacier's behaviour over the last decade to better understand this behaviour. We find that when the floating ice (mélange) in front of the glacier freezes in place during the winter, it can control the glacier's speed and thinning rate. A recently colder ocean has strengthened this mélange, allowing the glacier to recoup some of its previous losses.
Andreas Köhler, Michał Pętlicki, Pierre-Marie Lefeuvre, Giuseppa Buscaino, Christopher Nuth, and Christian Weidle
The Cryosphere, 13, 3117–3137, https://doi.org/10.5194/tc-13-3117-2019, https://doi.org/10.5194/tc-13-3117-2019, 2019
Short summary
Short summary
Ice loss at the front of glaciers can be observed with high temporal resolution using seismometers. We combine seismic and underwater sound measurements of iceberg calving at Kronebreen, a glacier in Svalbard, with laser scanning of the glacier front. We develop a method to determine calving ice loss directly from seismic and underwater calving signals. This allowed us to quantify the contribution of calving to the total ice loss at the glacier front, which also includes underwater melting.
Akiko Sakai
The Cryosphere, 13, 2043–2049, https://doi.org/10.5194/tc-13-2043-2019, https://doi.org/10.5194/tc-13-2043-2019, 2019
Short summary
Short summary
The Glacier Area Mapping for Discharge from the Asian Mountains (GAMDAM) glacier inventory was updated to revise the underestimated glacier area in the first version. The total number and area of glaciers are 134 770 and 100 693 ± 11 790 km2 from 453 Landsat images, which were carefully selected for the period from 1990 to 2010, to avoid mountain shadow, cloud cover, and seasonal snow cover.
Fanny Brun, Patrick Wagnon, Etienne Berthier, Joseph M. Shea, Walter W. Immerzeel, Philip D. A. Kraaijenbrink, Christian Vincent, Camille Reverchon, Dibas Shrestha, and Yves Arnaud
The Cryosphere, 12, 3439–3457, https://doi.org/10.5194/tc-12-3439-2018, https://doi.org/10.5194/tc-12-3439-2018, 2018
Short summary
Short summary
On debris-covered glaciers, steep ice cliffs experience dramatically enhanced melt compared with the surrounding debris-covered ice. Using field measurements, UAV data and submetre satellite imagery, we estimate the cliff contribution to 2 years of ablation on a debris-covered tongue in Nepal, carefully taking into account ice dynamics. While they occupy only 7 to 8 % of the tongue surface, ice cliffs contributed to 23 to 24 % of the total tongue ablation.
Dorothée Vallot, Jan Åström, Thomas Zwinger, Rickard Pettersson, Alistair Everett, Douglas I. Benn, Adrian Luckman, Ward J. J. van Pelt, Faezeh Nick, and Jack Kohler
The Cryosphere, 12, 609–625, https://doi.org/10.5194/tc-12-609-2018, https://doi.org/10.5194/tc-12-609-2018, 2018
Short summary
Short summary
This paper presents a new perspective on the role of ice dynamics and ocean interaction in glacier calving processes applied to Kronebreen, a tidewater glacier in Svalbard. A global modelling approach includes ice flow modelling, undercutting estimation by a combination of glacier energy balance and plume modelling as well as calving by a discrete particle model. We show that modelling undercutting is necessary and calving is influenced by basal friction velocity and geometry.
Damodar Lamsal, Koji Fujita, and Akiko Sakai
The Cryosphere, 11, 2815–2827, https://doi.org/10.5194/tc-11-2815-2017, https://doi.org/10.5194/tc-11-2815-2017, 2017
Short summary
Short summary
This study presents the geodetic mass balance of Kanchenjunga Glacier, a heavily debris-covered glacier in the easternmost Nepal Himalaya, between 1975 and 2010 using high-resolution DEMs. The rate of elevation change positively correlates with elevation and glacier velocity, and significant surface lowering is observed at supraglacial ponds. A difference in pond density would strongly affect the different geodetic mass balances of the Kanchenjunga and Khumbu glaciers.
Guillaume Jouvet, Yvo Weidmann, Julien Seguinot, Martin Funk, Takahiro Abe, Daiki Sakakibara, Hakime Seddik, and Shin Sugiyama
The Cryosphere, 11, 911–921, https://doi.org/10.5194/tc-11-911-2017, https://doi.org/10.5194/tc-11-911-2017, 2017
Short summary
Short summary
In this study, we combine UAV (unmanned aerial vehicles) images taken over the Bowdoin Glacier, north-western Greenland, and a model describing the viscous motion of ice to track the propagation of crevasses responsible for the collapse of large icebergs at the glacier-ocean front (calving). This new technique allows us to explain the systematic calving pattern observed in spring and summer of 2015 and anticipate a possible rapid retreat in the future.
M. Jeffrey Mei, David M. Holland, Sridhar Anandakrishnan, and Tiantian Zheng
The Cryosphere, 11, 609–618, https://doi.org/10.5194/tc-11-609-2017, https://doi.org/10.5194/tc-11-609-2017, 2017
Short summary
Short summary
We determine a method to locate calving at Helheim Glacier. By using local seismometers, we are able to find the calving location at a much higher precision than previous studies. The signal–onset time differences at four local seismic stations are used to determine possible seismic-wave origins. We present a catalogue of 12 calving events from 2014 to 2015, which shows that calving preferentially happens at the northern end of Helheim Glacier, which will help to constrain models of calving.
Owen King, Duncan J. Quincey, Jonathan L. Carrivick, and Ann V. Rowan
The Cryosphere, 11, 407–426, https://doi.org/10.5194/tc-11-407-2017, https://doi.org/10.5194/tc-11-407-2017, 2017
Short summary
Short summary
We used multiple digital elevation models to quantify melt on 32 glaciers in the Everest region of the Himalayas. We examined whether patterns of melt differed depending on whether the glacier terminated on land or in water. We found that glaciers terminating in large lakes had the highest melt rates, but that those terminating in small lakes had comparable melt rates to those terminating on land. We carried out this research because Himalayan people are highly dependent on glacier meltwater.
Torbjørn Ims Østby, Thomas Vikhamar Schuler, Jon Ove Hagen, Regine Hock, Jack Kohler, and Carleen H. Reijmer
The Cryosphere, 11, 191–215, https://doi.org/10.5194/tc-11-191-2017, https://doi.org/10.5194/tc-11-191-2017, 2017
Short summary
Short summary
We present modelled climatic mass balance for all glaciers in Svalbard for the period 1957–2014 at 1 km resolution using a coupled surface energy balance and snowpack model, thereby closing temporal and spatial gaps in direct and geodetic mass balance estimates.
Supporting previous studies, our results indicate increased mass loss over the period.
A detailed analysis of the involved energy fluxes reveals that increased mass loss is caused by atmospheric warming further amplified by feedbacks.
Nicholas E. Barrand, Robert G. Way, Trevor Bell, and Martin J. Sharp
The Cryosphere, 11, 157–168, https://doi.org/10.5194/tc-11-157-2017, https://doi.org/10.5194/tc-11-157-2017, 2017
Short summary
Short summary
This paper provides a comprehensive assessment of the state of small glaciers in the Canadian province of Labrador. These glaciers, the last in continental northeast North America, exist in heavily shaded locations within the remote Torngat Mountains National Park. Fieldwork, and airborne and spaceborne remote-sensing analyses were used to measure regional glacier area changes and individual glacier thinning rates. These results were then linked to trends in prevailing climatic conditions.
Argha Banerjee
The Cryosphere, 11, 133–138, https://doi.org/10.5194/tc-11-133-2017, https://doi.org/10.5194/tc-11-133-2017, 2017
Short summary
Short summary
Measurements of debris-covered and debris-free glaciers in the Himalaya-Karakoram show similar decadal scale thinning, despite a suppression of melt under the debris. Using physical arguments, supported by simulations of 1-D idealised glaciers, we analyse the evolution of thinning rates on both glacier types under a warming climate. The dynamics of the emergence velocity profile control the thinning rate evolution in general and lead to the observed trends in the thinning rate data.
Fangping Yan, Shichang Kang, Chaoliu Li, Yulan Zhang, Xiang Qin, Yang Li, Xiaopeng Zhang, Zhaofu Hu, Pengfei Chen, Xiaofei Li, Bin Qu, and Mika Sillanpää
The Cryosphere, 10, 2611–2621, https://doi.org/10.5194/tc-10-2611-2016, https://doi.org/10.5194/tc-10-2611-2016, 2016
Short summary
Short summary
DOC release of Laohugou Glacier No. 12 was 192 kg km−2 yr−1, of which 43.2 % could be decomposed and return to atmosphere as CO2 within 28 days, producing positive feedback in the warming process and influencing downstream ecosystems. Radiative forcing of snow pit DOC was calculated to be 0.43 W m−2, accounting for about 10 % of the radiative forcing caused by BC. Therefore, DOC is also a light-absorbing agent in glacierized regions, influencing the albedo of glacier surface and glacier melting.
Lindsey I. Nicholson, Michał Pętlicki, Ben Partan, and Shelley MacDonell
The Cryosphere, 10, 1897–1913, https://doi.org/10.5194/tc-10-1897-2016, https://doi.org/10.5194/tc-10-1897-2016, 2016
Short summary
Short summary
An Xbox Kinect sensor was used as a close-range surface scanner to produce the first accurate 3D surface models of spikes of snow and ice (known as penitentes) that develop in cold, dry, sunny conditions. The data collected show how penitentes develop over time and how they affect the surface roughness of a glacier. These surface models are useful inputs to modelling studies of how penitentes alter energy exchanges between the atmosphere and the surface and how this affects meltwater production.
Colleen M. Lynch, Iestyn D. Barr, Donal Mullan, and Alastair Ruffell
The Cryosphere, 10, 1809–1821, https://doi.org/10.5194/tc-10-1809-2016, https://doi.org/10.5194/tc-10-1809-2016, 2016
Short summary
Short summary
Early 21st century changes in the extent of glaciers on Kamchatka were manually mapped from satellite imagery. This revealed 673 glaciers, with a total surface area of 775.7 ± 27.9 km2 in 2000, and 738 glaciers, with a total area of 592.9 ± 20.4 km2 in 2014. This ~24 % decline in glacier surface area is considered to reflect variations in climate (particularly rising summer temperatures), though the response of individual glaciers was likely modulated by other (non-climatic) factors.
Christian Vincent, Patrick Wagnon, Joseph M. Shea, Walter W. Immerzeel, Philip Kraaijenbrink, Dibas Shrestha, Alvaro Soruco, Yves Arnaud, Fanny Brun, Etienne Berthier, and Sonam Futi Sherpa
The Cryosphere, 10, 1845–1858, https://doi.org/10.5194/tc-10-1845-2016, https://doi.org/10.5194/tc-10-1845-2016, 2016
Short summary
Short summary
Approximately 25 % of the glacierized area in the Everest region is covered by debris, yet the surface mass balance of these glaciers has not been measured directly. From terrestrial photogrammetry and unmanned aerial vehicle (UAV) methods, this study shows that the ablation is strongly reduced by the debris cover. The insulating effect of the debris cover has a larger effect on total mass loss than the enhanced ice ablation due to supraglacial ponds and exposed ice cliffs.
C. J. van der Veen
The Cryosphere, 10, 1331–1337, https://doi.org/10.5194/tc-10-1331-2016, https://doi.org/10.5194/tc-10-1331-2016, 2016
Short summary
Short summary
This paper evaluates the geometric force balance, with application to Byrd Glacier, Antarctica. It is concluded that this approach does not yield physically reasonable results.
Kjetil S. Aas, Thorben Dunse, Emily Collier, Thomas V. Schuler, Terje K. Berntsen, Jack Kohler, and Bartłomiej Luks
The Cryosphere, 10, 1089–1104, https://doi.org/10.5194/tc-10-1089-2016, https://doi.org/10.5194/tc-10-1089-2016, 2016
Short summary
Short summary
A high-resolution, coupled atmosphere--climatic mass balance (CMB) model is applied to Svalbard for the period 2003 to 2013. The mean CMB during this period is negative but displays large spatial and temporal variations. Comparison with observations on different scales shows a good overall model performance except for one particular glacier, where wind strongly affects the spatial patterns of CMB. The model also shows considerable sensitivity to model resolution, especially on local scales.
Ursula Weiser, Marc Olefs, Wolfgang Schöner, Gernot Weyss, and Bernhard Hynek
The Cryosphere, 10, 775–790, https://doi.org/10.5194/tc-10-775-2016, https://doi.org/10.5194/tc-10-775-2016, 2016
Short summary
Short summary
Geometric effects induced by tilt errors lead to erroneous measurement of snow albedo. These errors are corrected where tilts of sensors and slopes are unknown. Atmospheric parameters are taken from a nearby reference measurement or a radiation model. The developed model is fitted to the measured data to determine tilts and directions which vary daily due to changing atmospheric conditions and snow cover. The results show an obvious under- or overestimation of albedo depending on the slope direction.
M. Chernos, M. Koppes, and R. D. Moore
The Cryosphere, 10, 87–102, https://doi.org/10.5194/tc-10-87-2016, https://doi.org/10.5194/tc-10-87-2016, 2016
Short summary
Short summary
Ice loss from calving and surface melt is estimated at lake-terminating Bridge Glacier, British Columbia, Canada, from 1984 to 2013. Since the glacier's terminus began to float in 1991, calving has accounted for 10-25% of the glacier's total ice loss below the ELA. Overall, calving is a relatively small component of ice loss and is expected to decrease in importance in the future as the glacier retreats onto dry land. Hence, projections of future retreat remain dependent on climatic conditions.
B. Marzeion, P. W. Leclercq, J. G. Cogley, and A. H. Jarosch
The Cryosphere, 9, 2399–2404, https://doi.org/10.5194/tc-9-2399-2015, https://doi.org/10.5194/tc-9-2399-2015, 2015
Short summary
Short summary
We show that estimates of global glacier mass change during the 20th century, obtained from glacier-length-based reconstructions and from a glacier model driven by gridded climate observations are now consistent with each other and also with an estimate for the years 2003-2009 that is mostly based on remotely sensed data. This consistency is found throughout the entire common periods of the respective data sets. Inconsistencies of reconstructions and observations persist on regional scales.
T. Schellenberger, T. Dunse, A. Kääb, J. Kohler, and C. H. Reijmer
The Cryosphere, 9, 2339–2355, https://doi.org/10.5194/tc-9-2339-2015, https://doi.org/10.5194/tc-9-2339-2015, 2015
Short summary
Short summary
Kronebreen and Kongsbreen are among the fastest flowing glaciers on Svalbard, and surface speeds reached up to 3.2m d-1 at Kronebreen in summer 2013 and 2.7m d-1 at Kongsbreen in late autumn 2012 as retrieved from SAR satellite data. Both glaciers retreated significantly during the observation period, Kongsbreen up to 1800m or 2.5km2 and Kronebreen up to 850m or 2.8km2. Both glaciers are important contributors to the total dynamic mass loss from the Svalbard archipelago.
T. Smith, B. Bookhagen, and F. Cannon
The Cryosphere, 9, 1747–1759, https://doi.org/10.5194/tc-9-1747-2015, https://doi.org/10.5194/tc-9-1747-2015, 2015
Short summary
Short summary
We describe and apply a newly developed glacial mapping algorithm which uses spectral, topographic, velocity, and spatial data to quickly and accurately map glacial extents over a wide area. This method maps both clean glacier ice and debris-covered glacier tongues across diverse topographic, land cover, and spectral settings using primarily open-source tools.
C. Papasodoro, E. Berthier, A. Royer, C. Zdanowicz, and A. Langlois
The Cryosphere, 9, 1535–1550, https://doi.org/10.5194/tc-9-1535-2015, https://doi.org/10.5194/tc-9-1535-2015, 2015
Short summary
Short summary
Located at the far south (~62.5° N) of the Canadian Arctic, Grinnell and Terra Nivea Ice Caps are good climate proxies in this scarce data region. Multiple data sets (in situ, airborne and spaceborne) reveal changes in area, elevation and mass over the past 62 years. Ice wastage sharply accelerated during the last decade for both ice caps, as illustrated by the strongly negative mass balance of Terra Nivea over 2007-2014 (-1.77 ± 0.36 m a-1 w.e.). Possible climatic drivers are also discussed.
M. Trachsel and A. Nesje
The Cryosphere, 9, 1401–1414, https://doi.org/10.5194/tc-9-1401-2015, https://doi.org/10.5194/tc-9-1401-2015, 2015
Short summary
Short summary
We employ statistical models to model annual glacier mass balances of eight Scandinavian glaciers as function of summer temperature and winter precipitation.
Relative importances of winter precipitation and summer temperature vary in time.
Relative importances are influenced by AMO and NAO.
T. Abe and M. Furuya
The Cryosphere, 9, 1183–1190, https://doi.org/10.5194/tc-9-1183-2015, https://doi.org/10.5194/tc-9-1183-2015, 2015
Short summary
Short summary
Whereas glacier surge is known to often initiate in winter, we show significant winter speed-up signals in the upstream region even at quiescent surge-type glaciers in Yukon, Canada. Moreover, the winter speed-up region expanded from upstream to downstream. Given the absence of surface meltwater input in winter, we speculate the presence of englacial water storage that does not directly connect to the surface, yet can promote basal sliding through increased water pressure.
J. M. Shea, W. W. Immerzeel, P. Wagnon, C. Vincent, and S. Bajracharya
The Cryosphere, 9, 1105–1128, https://doi.org/10.5194/tc-9-1105-2015, https://doi.org/10.5194/tc-9-1105-2015, 2015
Short summary
Short summary
A glacier mass balance and redistribution model that integrates field observations and downscaled climate fields is developed to examine glacier sensitivity to future climate in the Everest region of Nepal. The modelled sensitivity of glaciers to future climate change is high, and glacier mass loss is sustained through the 21st century for both middle- and high-emission scenarios. Projected temperature increases will expose large glacier areas to melt and reduce snow accumulations.
T. Nuimura, A. Sakai, K. Taniguchi, H. Nagai, D. Lamsal, S. Tsutaki, A. Kozawa, Y. Hoshina, S. Takenaka, S. Omiya, K. Tsunematsu, P. Tshering, and K. Fujita
The Cryosphere, 9, 849–864, https://doi.org/10.5194/tc-9-849-2015, https://doi.org/10.5194/tc-9-849-2015, 2015
Short summary
Short summary
We present a new glacier inventory for high-mountain Asia named “Glacier Area Mapping for Discharge from the Asian Mountains” (GAMDAM). Glacier outlines were delineated manually using 356 Landsat ETM+ scenes in 226 path-row sets from the period 1999–2003, in conjunction with a digital elevation model and high-resolution Google EarthTM imagery. Our GAMDAM Glacier Inventory includes 87,084 glaciers covering a total area of 91,263 ± 13,689 km2 throughout high-mountain Asia.
A. Sakai, T. Nuimura, K. Fujita, S. Takenaka, H. Nagai, and D. Lamsal
The Cryosphere, 9, 865–880, https://doi.org/10.5194/tc-9-865-2015, https://doi.org/10.5194/tc-9-865-2015, 2015
Short summary
Short summary
Among meteorological elements, precipitation has a large spatial variability and less observation, particularly in high-mountain Asia, although precipitation in mountains is an important parameter for hydrological circulation. Based on the GAMDAM glacier inventory, we estimated precipitation contributing to glacier mass at the median elevation of glaciers, which is presumed to be at equilibrium-line altitude, by tuning adjustment parameters of precipitation.
J. Oerlemans and W. J. J. van Pelt
The Cryosphere, 9, 767–779, https://doi.org/10.5194/tc-9-767-2015, https://doi.org/10.5194/tc-9-767-2015, 2015
Short summary
Short summary
Many glaciers on Svalbard are surging glaciers. A surge is a rapid advance of the glacier snout during a few years, followed by a long period of quiescence. During the surge ice flows to lower terrain and experiences higher melt rates in summer. Here we investigate the impact of surging on the long-term effects of climate warming. We have modelled Abrahamsenbreen in northern Spitsbergen as a typical case. We show that surges tend to accelerate glacier retreat when temperature increases.
D. H. Shangguan, T. Bolch, Y. J. Ding, M. Kröhnert, T. Pieczonka, H. U. Wetzel, and S. Y. Liu
The Cryosphere, 9, 703–717, https://doi.org/10.5194/tc-9-703-2015, https://doi.org/10.5194/tc-9-703-2015, 2015
Short summary
Short summary
Glacier velocity, glacier area, surface elevation and mass changes of the Southern and Northern Inylchek Glacier were investigated by using multi-temporal space-borne data sets. The mass balance of both SIG and NIG was negative(-0.43 ± 0.10 m w.e. a-1 and -0.25 ± 0.10 m w.e. a-1) from ~1975 to 2007. The thinning at the lake dam was higher, likely caused by calving into Lake Merzbacher. Thus, glacier thinning and glacier flow are significantly influenced by the lake.
H. Hannesdóttir, H. Björnsson, F. Pálsson, G. Aðalgeirsdóttir, and Sv. Guðmundsson
The Cryosphere, 9, 565–585, https://doi.org/10.5194/tc-9-565-2015, https://doi.org/10.5194/tc-9-565-2015, 2015
Cited articles
Arendt, A., Bliss, A., Bolch, T., Cogley, J. G., Gardner, A. S., Hagen, J.-O., Hock, R., Huss, M., Kaser, G., Kienholz, C., Pfeffer, W. T., Moholdt, G., Paul, F., Radić, V., Andreassen, L., Bajracharya, S., Barrand, N. E., Beedle, M., Berthier, E., Bhambri, R., Brown, I., Burgess, E., Burgess, D., Cawkwell, F., Chinn, T., Copland, L., Davies, B., De Angelis, H., Dolgova, E., Earl, L., Filbert, K., Forester, R., Fountain, A. G., Frey, H., Giffen, B., Glasser, N., Guo, W. Q., Gurney, S., Hagg, W., Hall, D., Haritashya, U. K., Hartmann, G., Helm, C., Herreid, S., Howat, I., Kapustin, G., Khromova, T., König, M., Kohler, J., Kriegel, D., Kutuzov, S., Lavrentiev, I., LeBris, R., Liu, S. Y., Lund, J., Manley, W., Marti, R., Mayer, C., Miles, E. S., Li, X., Menounos, B., Mercer, A., Mölg, N., Mool, P., Nosenko, G., Negrete, A., Nuimura, T., Nuth, C., Pettersson, R., Racoviteanu, A., Ranzi, R., Rastner, P., Rau, F., Raup, B., Rich, J., Rott, H., Sakai, A., Schneider, C., Seliverstov, Y., Sharp, M., Sigurðsson, O., Stokes, C., Way, R. G., Wheate, R., Winsvold, S., Wolken, G., Wyatt, F., and Zheltyhina, N.: Randolph Glacier Inventory – A Dataset of Global Glacier Outlines: Version 5.0. Global Land Ice Measurements from Space, Boulder Colorado, USA, Digital Media, 2015.
Bamler, R. and Hartl, P.: Synthetic Aperture Radar Interferometry, Inverse Probl., 14, R1–R54, 1998.
Barboux, C., Strozzi, T., Delaloye, R., Wegmüller, U., and Collet, C.: Mapping slope movements in Alpine environments using TerraSAR-X interferometric methods, Journal of Photogrammetry and Remote Sensing, 109, 178–192, https://doi.org/10.1016/j.isprsjprs.2015.09.010, 2015.
Blaszczyk, M., Jania, J. A., and Hagen, J. O.: Tidewater glaciers of Svalbard: Recent changes and estimates of calving fluxes, Pol. Polar Res., 30, 85–142, 2009.
Burgess, E. W., Forster, R. R., and Larsen, C. F.: Flow velocities of Alaskan glaciers, Nat. Commun., 4, 2146, https://doi.org/10.1038/ncomms3146, 2013.
Church, J., Clark, P., Cazenave, A., Gregory, J., KhanJevrejeva, S. A., Levermann, A., Merrifield, M., Milne, G., Nerem, R., Nunn, P., Payne, A., Pfeffer, W., Stammer, D., and Unnikrishnan, A. S.: Sea Level Change, in: Climate Change 2013: The Physical Science Basis, Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Stocker, T. F., Qin, D., Plattner, G.-K., Tignor, M., Allen, S. K., Boschung, J., Nauels, A., Xia, Y., Bex, V., and Midgley, P. M., Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 2013.
Clarke, G. K. C.: Fast glacier flow: Ice streams, surging, and tidewater glaciers, J. Geophys. Res., 92, 8835–8841, https://doi.org/10.1029/JB092iB09p08835, 1987.
Cuffey, K. and Paterson, W. S. B.: The physics of glaciers, 4th Edn., Burlington and Oxford, Butterworth-Heinemann, 2010.
Debella-Gilo, M. and Kääb, A.: Sub-pixel precision image matching for measuring surface displacements on mass movements using normalized cross-correlation, Remote Sens. Environ., 115, 130–142, https://doi.org/10.1016/j.rse.2010.08.012, 2011.
DLR EOC: Earth Observation Center: TanDEM-X Ground Segment DEM Products Specification Document, Issue 3.0, 2013.
Dowdeswell, J. and Bamber, J.: On the glaciology of Edgeøya and Barentsøya, Svalbard, Polar Res., 14, 105–122, https://doi.org/10.3402/polar.v14i2.6658, 1995.
Dowdeswell, Benham, T., Strozzi, T., and Hagen, J. O.: Iceberg calving flux and mass balance of the Austfonna ice cap on Nordaustlandet, Svalbard, J. Geophys. Res., 133, F03022, https://doi.org/10.1029/2007JF000905, 2008.
Dunse, T., Schuler, T. V., Hagen, J. O., and Reijmer, C. H.: Seasonal speed-up of two outlet glaciers of Austfonna, Svalbard, inferred from continuous GPS measurements, The Cryosphere, 6, 453–466, https://doi.org/10.5194/tc-6-453-2012, 2012.
Dunse, T., Schellenberger, T., Hagen, J. O., Kääb, A., Schuler, T. V., and Reijmer, C. H.: Glacier-surge mechanisms promoted by a hydro-thermodynamic feedback to summer melt, The Cryosphere, 9, 197–215, https://doi.org/10.5194/tc-9-197-2015, 2015.
Hagen, J. O., Kohler, J., Melvold, K., and Winther, J. G.: Glaciers in Svalbard: Mass balance, runoff and freshwater flux, Polar Res., 22, 145–159, https://doi.org/10.3402/polar.v22i2.6452, 2003.
Heid, T. and Kääb, A.: Evaluation of existing image matching methods for deriving glacier surface displacements globally from optical satellite imagery, Remote Sens. Environ., 118, 339–355, https://doi.org/10.1016/j.rse.2011.11.024, 2012.
Kääb, A. and Vollmer, M.: Surface geometry, thickness changes and flow fields on creeping mountain permafrost: automatic extraction by digital image analysis, Permafrost Periglac., 11, 315–326, 2000.
Kääb, A.: Glacier Volume Changes Using ASTER Satellite Stereo and ICESat GLAS Laser Altimetry, A Test Study on Edgeøya, Eastern Svalbard, IEEE Trans. Geosc. Rem. Sens., 46, 2823–2830, https://doi.org/10.1109/TGRS.2008.2000627, 2008.
Kääb, A., Winsvold, S. H., Altena, B., Nuth, C., Nagler, T., and Wuite, J.: Glacier remote sensing using Sentinel-2. Part I: Radiometric and geometric performance, and application to ice velocity, Remote Sens., 8, 598, https://doi.org/10.3390/rs8070598, 2016.
Khan, S. A., Aschwanden, A., Bjørk, A., Wahr, J., Kjeldsen, K. K., and Kjær, K. H.: Greenland ice sheet mass balance: a review, Rep. Prog. Phys., 78, https://doi.org/10.1088/0034-4885/78/4/046801, 2015.
Lamont J.: Notes about Spitzbergen in 1859, Proc. Geol. Soc. Mar., 28, 1860.
Lefauconnier, B. and Hagen, J. O.: Surging and calving glaciers in Eastern Svalbard, Meddelelser Nr. 116, Norsk Polarinstitutt, Oslo, 1991.
Liestøl, O.: Glaciers of Svalbard, Norway, US Geological Survey, Professional Paper 1386-E-5, E127–151, 1983.
LPDAAC: Land Processes Distributed Active Archive Center, ASTER Products, AST14DEM, available at: https://lpdaac.usgs.gov/dataset_discovery/aster/aster_products_table/ast14dem, last access: 15 August 2016.
Luckman, A., Benn, D. I., Cottier, F., Bevan, S., Nilsen, F., and Inall, M.: Calving rates at tidewater glaciers vary strongly with ocean temperature, Nat. Commun., 6, 8566, https://doi.org/10.1038/ncomms9566, 2015.
McMillan, M., Shepherd, A., Gourmelen, N., Dehecq, A., Leeson, A., Ridout, A., Flament, T., Hogg, A., Gilbert, L., Benham, T., van den Broeke, M., Dowdeswell, J., Fettweis, X., Noël, B., and Strozzi, T.: Rapid dynamic activation of a marine-based Arctic ice cap, Geophys. Res. Lett., 41, 8902–8909, https://doi.org/10.1002/2014GL062255, 2014.
McNabb, R. W., Hock, R., and Huss, M.: Variations in Alaska tidewater glacier frontal ablation, 1985–2013, J. Geophys. Res. Earth Surf., 120, 120–136, https://doi.org/10.1002/2014JF003276, 2015.
Mohr, J. J., Reeh, N., and Madsen, S.: Three-dimensional glacial flow and surface elevation measured with radar interferometry, Nature, 391, 273–276, https://doi.org/10.1038/34635, 1998.
Moholdt, G., Nuth, C., Hagen, J. O., and Kohler, J.: Recent elevation changes of Svalbard glaciers derived from ICESat laser altimetry, Remote Sens. Environ., 114, 2756–2767, https://doi.org/10.1016/j.rse.2010.06.008, 2010.
Murray, T., Strozzi, T., Luckman, A., Jiskoot, H., and Christakos, P.: Is there a single surge mechanism? Contrasts in dynamics between glacier surges in Svalbard and other regions, J. Geophys. Res., 108, 2237, https://doi.org/10.1029/2002JB001906, 2003.
Mouginot, J. and Rignot, E.: Ice motion of the Patagonian Icefields of South America: 1984–2014, Geophys. Res. Lett., 42, 1441–1449, https://doi.org/10.1002/2014GL062661, 2015.
Norwegian Polar Institute: Terrengmodell Svalbard (S0 Terrengmodell), Tromsø, Norway, Norwegian Polar Institute, https://doi.org/10.21334/npolar.2014.dce53a47, 2014.
Norwegian See Navigation Chart: Norgeskart, http://www.norgeskart.no/?&_ga=1.238123392.1431256724.1445342427#8/694467/8628444/-land/+sjo/+dekning.sjo, last access: 2 August 2016.
Nuth, C. and Kääb, A.: Co-registration and bias corrections of satellite elevation data sets for quantifying glacier thickness change, The Cryosphere, 5, 271–290, https://doi.org/10.5194/tc-5-271-2011, 2011.
Nuth, C., Kohler, J., König, M., von Deschwanden, A., Hagen, J. O., Kääb, A., Moholdt, G., and Pettersson, R.: Decadal changes from a multi-temporal glacier inventory of Svalbard, The Cryosphere, 7, 1603–1621, https://doi.org/10.5194/tc-7-1603-2013, 2013.
Paul, F., Bolch, T., Kääb, A., Nagler, T., Nuth, C., Scharrer, K., Shepherd, A., Strozzi, T., Ticconi, F., Bhambri, R., Berthier, E., Bevan, S., Gourmelen, N., Heid, T., Jeong, S., Kunz, M., Lauknes, T. R., Luckman, A., Merryman, J., Moholdt, G., Muir, A., Neelmeijer, J., Rankl, M., Van Looy, J., and Van Niel, T.: The glaciers climate change initiative: Methods for creating glacier area, elevation change and velocity products, Remote Sens. Environ., 162, 408–426, https://doi.org/10.1016/j.rse.2013.07.043, 2015.
Przyłucka, M., Herrera, G., Graniczny, M., Colombo, D., and Béjar-Pizarro, M.: Combination of Conventional and Advanced DInSAR to Monitor Very Fast Mining Subsidence with TerraSAR-X Data: Bytom City (Poland), Remote Sens., 7, 5300–5328, https://doi.org/10.3390/rs70505300, 2015.
Rignot, E., Bamber, J., van den Broeke, M. R., Davis, C., Li, Y., van de Berg, W. J., and van Meijgaard, E.: Recent Antarctic ice mass loss from radar interferometry and regional climate modelling, Nat. Geosci., 1, 106–110, https://doi.org/10.1038/ngeo102, 2008.
Rosen, P., Hensley, S., Joughin, I., Li, F., Madsen, S., Rodriguez, E., and Goldstein, R.: Synthetic Aperture Radar Interferometry, P. IEEE, 88, 333–382, https://doi.org/10.1109/5.838084, 2000.
Schellenberger, T., Dunse, T., Kääb, A., Kohler, J., and Reijmer, C. H.: Surface speed and frontal ablation of Kronebreen and Kongsbreen, NW Svalbard, from SAR offset tracking, The Cryosphere, 9, 2339–2355, https://doi.org/10.5194/tc-9-2339-2015, 2015.
Schellenberger, T., Van Wychen, W., Copland, L., Kääb, A., and Gray, L.: An inter-comparison of techniques for determining velocities of maritime Arctic glaciers, Svalbard, using Radarsat-2 Wide Fine mode data, Remote Sens., 8, 785, https://doi.org/10.3390/rs8090785, 2016.
Spreckels, V., Wegmüller, U., Strozzi, T., Musiedlak, J., and Wichlacz, H. C.: Detection and observation of underground coal mining-induced surface deformation with differential SAR interferometry, Proc. Joint Workshop of ISPRS Working Groups I/2, I/5 and IV/7 “High Resolution Mapping from Space”, Hannover, Germany, 19–21 September 2001.
Strozzi, T., Wegmüller, U., and Mätzler, C.: Mapping Wet Snowcovers with SAR Interferometry, Int. J. Remote Sens., 20, 2395–2403, https://doi.org/10.1080/014311699212083, 1999.
Strozzi, T., Wegmüller, U., Tosi, L., Bitelli, G., and Spreckels, V.: Land Subsidence Monitoring with Differential SAR Interferometry, Photogramm. Eng. Rem. S., 67, 1261–1270, 2001.
Strozzi, T., Luckman, A., Murray, T., Wegmüller, U., and Werner, C.: Glacier motion estimation using SAR offset-tracking procedures, IEEE T. Geosci. Remote, 40, 2384–2391, https://doi.org/10.1109/TGRS.2002.805079, 2002.
Sund, M., Lauknes, T. R., and Eiken, T.: Surge dynamics in the Nathorstbreen glacier system, Svalbard, The Cryosphere, 8, 623–638, https://doi.org/10.5194/tc-8-623-2014, 2014.
Van der Veen, C. J.: Tidewater calving, J. Glaciol., 42, 375–385, 1996.
Van Wychen, W., Davis, J., Burgess, D. O., Copland, L., Gray, L., Sharp, M., and Mortimer, C.: Characterizing interannual variability of glacier dynamics and dynamic discharge (1999–2015) for the ice masses of Ellesmere and Axel Heiberg Islands, Nunavut, Canada, J. Geophys. Res.-Earth, 121, 39–63, https://doi.org/10.1002/2015JF003708, 2016.
Vieli, A., Funk, M., and Blatter H.: Flow dynamics of tidewater glaciers: a numerical modelling approach, J. Glaciol., 47, 595–606, https://doi.org/10.3189/172756501781831747, 2001.
Wegmüller, U., Bonforte, A., De Beni, E., Guglielmino, F., and Strozzi, T.: Morphological changes at Mt. Etna detected by TanDEM-X, Geophys. Res. Abstracts, 16, 2014.
Werner, C., Wegmüller, U., Strozzi, T., and Wiesmann, A.: Processing strategies for phase unwrapping for INSAR applications, Proceedings of the European Conference on Synthetic Aperture Radar EUSAR, Cologne, Germany, 4–6 June 2002.
Short summary
The strong atmospheric warming observed since the 1990s in polar regions requires quantifying the contribution to sea level rise of glaciers and ice caps, but for large areas we do not have much information on ice dynamic fluctuations. The recent increase in satellite data opens up new possibilities to monitor ice flow. We observed over Stonebreen on Edgeøya (Svalbard) a strong increase since 2012 in ice surface velocity along with a decrease in volume and an advance in frontal extension.
The strong atmospheric warming observed since the 1990s in polar regions requires quantifying...
