Articles | Volume 18, issue 8
https://doi.org/10.5194/tc-18-3875-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/tc-18-3875-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
30 Aug 2024
Research article |
| 30 Aug 2024
| 30 Aug 2024
Layer-optimized synthetic aperture radar processing with a mobile phase-sensitive radar: a proof of concept for detecting the deep englacial stratigraphy of Colle Gnifetti, Switzerland and Italy
Falk M. Oraschewski
CORRESPONDING AUTHOR
Department of Geosciences, University of Tübingen, Tübingen, Germany
Inka Koch
Department of Geosciences, University of Tübingen, Tübingen, Germany
M. Reza Ershadi
Department of Geosciences, University of Tübingen, Tübingen, Germany
Jonathan D. Hawkins
School of Earth and Environmental Sciences, Cardiff University, Cardiff, Wales, United Kingdom
Olaf Eisen
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
Department of Geosciences, University of Bremen, Bremen, Germany
Reinhard Drews
Department of Geosciences, University of Tübingen, Tübingen, Germany
Related authors
Robert G. Bingham, Julien A. Bodart, Marie G. P. Cavitte, Ailsa Chung, Rebecca J. Sanderson, Johannes C. R. Sutter, Olaf Eisen, Nanna B. Karlsson, Joseph A. MacGregor, Neil Ross, Duncan A. Young, David W. Ashmore, Andreas Born, Winnie Chu, Xiangbin Cui, Reinhard Drews, Steven Franke, Vikram Goel, John W. Goodge, A. Clara J. Henry, Antoine Hermant, Benjamin H. Hills, Nicholas Holschuh, Michelle R. Koutnik, Gwendolyn J.-M. C. Leysinger Vieli, Emma J. Mackie, Elisa Mantelli, Carlos Martín, Felix S. L. Ng, Falk M. Oraschewski, Felipe Napoleoni, Frédéric Parrenin, Sergey V. Popov, Therese Rieckh, Rebecca Schlegel, Dustin M. Schroeder, Martin J. Siegert, Xueyuan Tang, Thomas O. Teisberg, Kate Winter, Shuai Yan, Harry Davis, Christine F. Dow, Tyler J. Fudge, Tom A. Jordan, Bernd Kulessa, Kenichi Matsuoka, Clara J. Nyqvist, Maryam Rahnemoonfar, Matthew R. Siegfried, Shivangini Singh, Verjan Višnjević, Rodrigo Zamora, and Alexandra Zuhr
EGUsphere, https://doi.org/10.5194/egusphere-2024-2593, https://doi.org/10.5194/egusphere-2024-2593, 2024
Short summary
Short summary
The ice sheets covering Antarctica have built up over millenia through successive snowfall events which become buried and preserved as internal surfaces of equal age detectable with ice-penetrating radar. This paper describes an international initiative to work together on this archival data to build a comprehensive 3-D picture of how old the ice is everywhere across Antarctica, and how this will be used to reconstruct past and predict future ice and climate behaviour.
Falk M. Oraschewski and Aslak Grinsted
The Cryosphere, 16, 2683–2700, https://doi.org/10.5194/tc-16-2683-2022, https://doi.org/10.5194/tc-16-2683-2022, 2022
Short summary
Short summary
Old snow (denoted as firn) accumulates in the interior of ice sheets and gets densified into glacial ice. Typically, this densification is assumed to only depend on temperature and accumulation rate. However, it has been observed that stretching of the firn by horizontal flow also enhances this process. Here, we show how to include this effect in classical firn models. With the model we confirm that softening of the firn controls firn densification in areas with strong horizontal stretching.
Emma Pearce, Dimitri Zigone, Coen Hofstede, Andreas Fichtner, Joachim Rimpot, Sune Olander Rasmussen, Johannes Freitag, and Olaf Eisen
The Cryosphere, 18, 4917–4932, https://doi.org/10.5194/tc-18-4917-2024, https://doi.org/10.5194/tc-18-4917-2024, 2024
Short summary
Short summary
Our study near EastGRIP camp in Greenland shows varying firn properties by direction (crucial for studying ice stream stability, structure, surface mass balance, and past climate conditions). We used dispersion curve analysis of Love and Rayleigh waves to show firn is nonuniform along and across the flow of an ice stream due to wind patterns, seasonal variability, and the proximity to the edge of the ice stream. This method better informs firn structure, advancing ice stream understanding.
Robert G. Bingham, Julien A. Bodart, Marie G. P. Cavitte, Ailsa Chung, Rebecca J. Sanderson, Johannes C. R. Sutter, Olaf Eisen, Nanna B. Karlsson, Joseph A. MacGregor, Neil Ross, Duncan A. Young, David W. Ashmore, Andreas Born, Winnie Chu, Xiangbin Cui, Reinhard Drews, Steven Franke, Vikram Goel, John W. Goodge, A. Clara J. Henry, Antoine Hermant, Benjamin H. Hills, Nicholas Holschuh, Michelle R. Koutnik, Gwendolyn J.-M. C. Leysinger Vieli, Emma J. Mackie, Elisa Mantelli, Carlos Martín, Felix S. L. Ng, Falk M. Oraschewski, Felipe Napoleoni, Frédéric Parrenin, Sergey V. Popov, Therese Rieckh, Rebecca Schlegel, Dustin M. Schroeder, Martin J. Siegert, Xueyuan Tang, Thomas O. Teisberg, Kate Winter, Shuai Yan, Harry Davis, Christine F. Dow, Tyler J. Fudge, Tom A. Jordan, Bernd Kulessa, Kenichi Matsuoka, Clara J. Nyqvist, Maryam Rahnemoonfar, Matthew R. Siegfried, Shivangini Singh, Verjan Višnjević, Rodrigo Zamora, and Alexandra Zuhr
EGUsphere, https://doi.org/10.5194/egusphere-2024-2593, https://doi.org/10.5194/egusphere-2024-2593, 2024
Short summary
Short summary
The ice sheets covering Antarctica have built up over millenia through successive snowfall events which become buried and preserved as internal surfaces of equal age detectable with ice-penetrating radar. This paper describes an international initiative to work together on this archival data to build a comprehensive 3-D picture of how old the ice is everywhere across Antarctica, and how this will be used to reconstruct past and predict future ice and climate behaviour.
Tamara Annina Gerber, David A. Lilien, Niels F. Nymand, Daniel Steinhage, Olaf Eisen, and Dorthe Dahl-Jensen
EGUsphere, https://doi.org/10.5194/egusphere-2024-2276, https://doi.org/10.5194/egusphere-2024-2276, 2024
Short summary
Short summary
This study explores how anisotropic scattering and birefringence affect radar signals in ice sheets. Analyzing data from Northeast Greenland, we found anisotropic scattering, caused by small changes in ice crystals, dominates the azimuthal power response. We observe a strong link between scattering strength, orientation, and ice-sheet stratigraphy. Anisotropic scattering can thus be used to determine ice crystal orientation and distinguish ice units from different climatic periods.
Steven Franke, Daniel Steinhage, Veit Helm, Alexandra M. Zuhr, Julien A. Bodart, Olaf Eisen, and Paul Bons
EGUsphere, https://doi.org/10.5194/egusphere-2024-2349, https://doi.org/10.5194/egusphere-2024-2349, 2024
Short summary
Short summary
We use radar technology to study the internal architecture of the ice sheet in western DML, East Antarctica. We identified and dated nine internal reflection horizons (IRHs), revealing important information about the ice sheet's history and dynamics. Some IRHs can be linked to past volcanic eruptions and are of similar age to IRHs detected in other parts of Antarctica. Our findings enhance our understanding of ice sheet behaviour and aid in developing better models for predicting future changes.
Ole Zeising, Tore Hattermann, Lars Kaleschke, Sophie Berger, Reinhard Drews, M. Reza Ershadi, Tanja Fromm, Frank Pattyn, Daniel Steinhage, and Olaf Eisen
EGUsphere, https://doi.org/10.5194/egusphere-2024-2109, https://doi.org/10.5194/egusphere-2024-2109, 2024
Short summary
Short summary
Basal melting of ice shelves impacts the mass loss of the Antarctic Ice Sheet. This study focuses on the Ekström Ice Shelf in East Antarctica, using multi-year data from an autonomous radar system. Results show a surprising seasonal pattern of high melt rates in winter and spring. Sea-ice growth correlates with melt rates, indicating that in winter, dense water enhances plume activity and melt rates. Understanding these dynamics is crucial for improving future mass balance projections.
Hameed Moqadam and Olaf Eisen
EGUsphere, https://doi.org/10.5194/egusphere-2024-1674, https://doi.org/10.5194/egusphere-2024-1674, 2024
Short summary
Short summary
This is an overview on methodologies that have been applied to map the internal reflection horizons, or ice-layer boundaries, of ice sheets on earth and other planets. We briefly explain radar applications in glaciology and the methods which have been used and published. There are summaries of the published work of the last two decades. Finally, we conclude by introducing the gaps and opportunities for further advancement in this field, and present possible future directions.
Ailsa Chung, Frédéric Parrenin, Robert Mulvaney, Luca Vittuari, Massimo Frezzotti, Antonio Zanutta, David A. Lilien, Marie G. P. Cavitte, and Olaf Eisen
EGUsphere, https://doi.org/10.5194/egusphere-2024-1650, https://doi.org/10.5194/egusphere-2024-1650, 2024
Short summary
Short summary
We applied an ice flow model to a flow line from the summit of Dome C to the Beyond EPICA ice core drill site on Little Dome C in Antarctica. Results show that the oldest ice at the drill site may be 1.12 Ma (at age density of 20 kyr/m) and originate from around 15 km upstream. We also discuss the nature of the 200–250 m thick basal layer which could be composed of accreted ice, stagnant ice, or even disturbed ice containing debris.
Ladina Steiner, Holger Schmithüsen, Jens Wickert, and Olaf Eisen
The Cryosphere, 17, 4903–4916, https://doi.org/10.5194/tc-17-4903-2023, https://doi.org/10.5194/tc-17-4903-2023, 2023
Short summary
Short summary
The present study illustrates the potential of a combined Global Navigation Satellite System reflectometry and refractometry (GNSS-RR) method for accurate, simultaneous, and continuous estimation of in situ snow accumulation, snow water equivalent, and snow density time series. The combined GNSS-RR method was successfully applied on a fast-moving, polar ice shelf. The combined GNSS-RR approach could be highly advantageous for a continuous quantification of ice sheet surface mass balances.
Zhuo Wang, Ailsa Chung, Daniel Steinhage, Frédéric Parrenin, Johannes Freitag, and Olaf Eisen
The Cryosphere, 17, 4297–4314, https://doi.org/10.5194/tc-17-4297-2023, https://doi.org/10.5194/tc-17-4297-2023, 2023
Short summary
Short summary
We combine radar-based observed internal layer stratigraphy of the ice sheet with a 1-D ice flow model in the Dome Fuji region. This results in maps of age and age density of the basal ice, the basal thermal conditions, and reconstructed accumulation rates. Based on modeled age we then identify four potential candidates for ice which is potentially 1.5 Myr old. Our map of basal thermal conditions indicates that melting prevails over the presence of stagnant ice in the study area.
Ailsa Chung, Frédéric Parrenin, Daniel Steinhage, Robert Mulvaney, Carlos Martín, Marie G. P. Cavitte, David A. Lilien, Veit Helm, Drew Taylor, Prasad Gogineni, Catherine Ritz, Massimo Frezzotti, Charles O'Neill, Heinrich Miller, Dorthe Dahl-Jensen, and Olaf Eisen
The Cryosphere, 17, 3461–3483, https://doi.org/10.5194/tc-17-3461-2023, https://doi.org/10.5194/tc-17-3461-2023, 2023
Short summary
Short summary
We combined a numerical model with radar measurements in order to determine the age of ice in the Dome C region of Antarctica. Our results show that at the current ice core drilling sites on Little Dome C, the maximum age of the ice is almost 1.5 Ma. We also highlight a new potential drill site called North Patch with ice up to 2 Ma. Finally, we explore the nature of a stagnant ice layer at the base of the ice sheet which has been independently observed and modelled but is not well understood.
Alice C. Frémand, Peter Fretwell, Julien A. Bodart, Hamish D. Pritchard, Alan Aitken, Jonathan L. Bamber, Robin Bell, Cesidio Bianchi, Robert G. Bingham, Donald D. Blankenship, Gino Casassa, Ginny Catania, Knut Christianson, Howard Conway, Hugh F. J. Corr, Xiangbin Cui, Detlef Damaske, Volkmar Damm, Reinhard Drews, Graeme Eagles, Olaf Eisen, Hannes Eisermann, Fausto Ferraccioli, Elena Field, René Forsberg, Steven Franke, Shuji Fujita, Yonggyu Gim, Vikram Goel, Siva Prasad Gogineni, Jamin Greenbaum, Benjamin Hills, Richard C. A. Hindmarsh, Andrew O. Hoffman, Per Holmlund, Nicholas Holschuh, John W. Holt, Annika N. Horlings, Angelika Humbert, Robert W. Jacobel, Daniela Jansen, Adrian Jenkins, Wilfried Jokat, Tom Jordan, Edward King, Jack Kohler, William Krabill, Mette Kusk Gillespie, Kirsty Langley, Joohan Lee, German Leitchenkov, Carlton Leuschen, Bruce Luyendyk, Joseph MacGregor, Emma MacKie, Kenichi Matsuoka, Mathieu Morlighem, Jérémie Mouginot, Frank O. Nitsche, Yoshifumi Nogi, Ole A. Nost, John Paden, Frank Pattyn, Sergey V. Popov, Eric Rignot, David M. Rippin, Andrés Rivera, Jason Roberts, Neil Ross, Anotonia Ruppel, Dustin M. Schroeder, Martin J. Siegert, Andrew M. Smith, Daniel Steinhage, Michael Studinger, Bo Sun, Ignazio Tabacco, Kirsty Tinto, Stefano Urbini, David Vaughan, Brian C. Welch, Douglas S. Wilson, Duncan A. Young, and Achille Zirizzotti
Earth Syst. Sci. Data, 15, 2695–2710, https://doi.org/10.5194/essd-15-2695-2023, https://doi.org/10.5194/essd-15-2695-2023, 2023
Short summary
Short summary
This paper presents the release of over 60 years of ice thickness, bed elevation, and surface elevation data acquired over Antarctica by the international community. These data are a crucial component of the Antarctic Bedmap initiative which aims to produce a new map and datasets of Antarctic ice thickness and bed topography for the international glaciology and geophysical community.
Ole Zeising, Tamara Annina Gerber, Olaf Eisen, M. Reza Ershadi, Nicolas Stoll, Ilka Weikusat, and Angelika Humbert
The Cryosphere, 17, 1097–1105, https://doi.org/10.5194/tc-17-1097-2023, https://doi.org/10.5194/tc-17-1097-2023, 2023
Short summary
Short summary
The flow of glaciers and ice streams is influenced by crystal fabric orientation. Besides sparse ice cores, these can be investigated by radar measurements. Here, we present an improved method which allows us to infer the horizontal fabric asymmetry using polarimetric phase-sensitive radar data. A validation of the method on a deep ice core from the Greenland Ice Sheet shows an excellent agreement, which is a large improvement over previously used methods.
Vjeran Višnjević, Reinhard Drews, Clemens Schannwell, Inka Koch, Steven Franke, Daniela Jansen, and Olaf Eisen
The Cryosphere, 16, 4763–4777, https://doi.org/10.5194/tc-16-4763-2022, https://doi.org/10.5194/tc-16-4763-2022, 2022
Short summary
Short summary
We present a simple way to model the internal layers of an ice shelf and apply the method to the Roi Baudouin Ice Shelf in East Antarctica. Modeled results are compared to measurements obtained by radar. We distinguish between ice directly formed on the shelf and ice transported from the ice sheet, and we map the spatial changes in the volume of the locally accumulated ice. In this context, we discuss the sensitivity of the ice shelf to future changes in surface accumulation and basal melt.
Julian Gutt, Stefanie Arndt, David Keith Alan Barnes, Horst Bornemann, Thomas Brey, Olaf Eisen, Hauke Flores, Huw Griffiths, Christian Haas, Stefan Hain, Tore Hattermann, Christoph Held, Mario Hoppema, Enrique Isla, Markus Janout, Céline Le Bohec, Heike Link, Felix Christopher Mark, Sebastien Moreau, Scarlett Trimborn, Ilse van Opzeeland, Hans-Otto Pörtner, Fokje Schaafsma, Katharina Teschke, Sandra Tippenhauer, Anton Van de Putte, Mia Wege, Daniel Zitterbart, and Dieter Piepenburg
Biogeosciences, 19, 5313–5342, https://doi.org/10.5194/bg-19-5313-2022, https://doi.org/10.5194/bg-19-5313-2022, 2022
Short summary
Short summary
Long-term ecological observations are key to assess, understand and predict impacts of environmental change on biotas. We present a multidisciplinary framework for such largely lacking investigations in the East Antarctic Southern Ocean, combined with case studies, experimental and modelling work. As climate change is still minor here but is projected to start soon, the timely implementation of this framework provides the unique opportunity to document its ecological impacts from the very onset.
A. Clara J. Henry, Reinhard Drews, Clemens Schannwell, and Vjeran Višnjević
The Cryosphere, 16, 3889–3905, https://doi.org/10.5194/tc-16-3889-2022, https://doi.org/10.5194/tc-16-3889-2022, 2022
Short summary
Short summary
We used a 3D, idealised model to study features in coastal Antarctica called ice rises and ice rumples. These features regulate the rate of ice flow into the ocean. We show that when sea level is raised or lowered, the size of these features and the ice flow pattern can change. We find that the features depend on the ice history and do not necessarily fully recover after an equal increase and decrease in sea level. This shows that it is important to initialise models with accurate ice geometry.
Falk M. Oraschewski and Aslak Grinsted
The Cryosphere, 16, 2683–2700, https://doi.org/10.5194/tc-16-2683-2022, https://doi.org/10.5194/tc-16-2683-2022, 2022
Short summary
Short summary
Old snow (denoted as firn) accumulates in the interior of ice sheets and gets densified into glacial ice. Typically, this densification is assumed to only depend on temperature and accumulation rate. However, it has been observed that stretching of the firn by horizontal flow also enhances this process. Here, we show how to include this effect in classical firn models. With the model we confirm that softening of the firn controls firn densification in areas with strong horizontal stretching.
Chaman Gul, Shichang Kang, Siva Praveen Puppala, Xiaokang Wu, Cenlin He, Yangyang Xu, Inka Koch, Sher Muhammad, Rajesh Kumar, and Getachew Dubache
Atmos. Chem. Phys., 22, 8725–8737, https://doi.org/10.5194/acp-22-8725-2022, https://doi.org/10.5194/acp-22-8725-2022, 2022
Short summary
Short summary
This work aims to understand concentrations, spatial variability, and potential source regions of light-absorbing impurities (black carbon aerosols, dust particles, and organic carbon) in the surface snow of central and western Himalayan glaciers and their impact on snow albedo and radiative forcing.
Astrid Oetting, Emma C. Smith, Jan Erik Arndt, Boris Dorschel, Reinhard Drews, Todd A. Ehlers, Christoph Gaedicke, Coen Hofstede, Johann P. Klages, Gerhard Kuhn, Astrid Lambrecht, Andreas Läufer, Christoph Mayer, Ralf Tiedemann, Frank Wilhelms, and Olaf Eisen
The Cryosphere, 16, 2051–2066, https://doi.org/10.5194/tc-16-2051-2022, https://doi.org/10.5194/tc-16-2051-2022, 2022
Short summary
Short summary
This study combines a variety of geophysical measurements in front of and beneath the Ekström Ice Shelf in order to identify and interpret geomorphological evidences of past ice sheet flow, extent and retreat.
The maximal extent of grounded ice in this region was 11 km away from the continental shelf break.
The thickness of palaeo-ice on the calving front around the LGM was estimated to be at least 305 to 320 m.
We provide essential boundary conditions for palaeo-ice-sheet models.
M. Reza Ershadi, Reinhard Drews, Carlos Martín, Olaf Eisen, Catherine Ritz, Hugh Corr, Julia Christmann, Ole Zeising, Angelika Humbert, and Robert Mulvaney
The Cryosphere, 16, 1719–1739, https://doi.org/10.5194/tc-16-1719-2022, https://doi.org/10.5194/tc-16-1719-2022, 2022
Short summary
Short summary
Radio waves transmitted through ice split up and inform us about the ice sheet interior and orientation of single ice crystals. This can be used to infer how ice flows and improve projections on how it will evolve in the future. Here we used an inverse approach and developed a new algorithm to infer ice properties from observed radar data. We applied this technique to the radar data obtained at two EPICA drilling sites, where ice cores were used to validate our results.
Steven Franke, Daniela Jansen, Tobias Binder, John D. Paden, Nils Dörr, Tamara A. Gerber, Heinrich Miller, Dorthe Dahl-Jensen, Veit Helm, Daniel Steinhage, Ilka Weikusat, Frank Wilhelms, and Olaf Eisen
Earth Syst. Sci. Data, 14, 763–779, https://doi.org/10.5194/essd-14-763-2022, https://doi.org/10.5194/essd-14-763-2022, 2022
Short summary
Short summary
The Northeast Greenland Ice Stream (NEGIS) is the largest ice stream in Greenland. In order to better understand the past and future dynamics of the NEGIS, we present a high-resolution airborne radar data set (EGRIP-NOR-2018) for the onset region of the NEGIS. The survey area is centered at the location of the drill site of the East Greenland Ice-Core Project (EastGRIP), and radar profiles cover both shear margins and are aligned parallel to several flow lines.
Johannes Sutter, Hubertus Fischer, and Olaf Eisen
The Cryosphere, 15, 3839–3860, https://doi.org/10.5194/tc-15-3839-2021, https://doi.org/10.5194/tc-15-3839-2021, 2021
Short summary
Short summary
Projections of global sea-level changes in a warming world require ice-sheet models. We expand the calibration of these models by making use of the internal architecture of the Antarctic ice sheet, which is formed by its evolution over many millennia. We propose that using our novel approach to constrain ice sheet models, we will be able to both sharpen our understanding of past and future sea-level changes and identify weaknesses in the parameterisation of current continental-scale models.
David A. Lilien, Daniel Steinhage, Drew Taylor, Frédéric Parrenin, Catherine Ritz, Robert Mulvaney, Carlos Martín, Jie-Bang Yan, Charles O'Neill, Massimo Frezzotti, Heinrich Miller, Prasad Gogineni, Dorthe Dahl-Jensen, and Olaf Eisen
The Cryosphere, 15, 1881–1888, https://doi.org/10.5194/tc-15-1881-2021, https://doi.org/10.5194/tc-15-1881-2021, 2021
Short summary
Short summary
We collected radar data between EDC, an ice core spanning ~800 000 years, and BELDC, the site chosen for a new
oldest icecore at nearby Little Dome C. These data allow us to identify 50 % older internal horizons than previously traced in the area. We fit a model to the ages of those horizons at BELDC to determine the age of deep ice there. We find that there is likely to be 1.5 Myr old ice ~265 m above the bed, with sufficient resolution to preserve desired climatic information.
Coen Hofstede, Sebastian Beyer, Hugh Corr, Olaf Eisen, Tore Hattermann, Veit Helm, Niklas Neckel, Emma C. Smith, Daniel Steinhage, Ole Zeising, and Angelika Humbert
The Cryosphere, 15, 1517–1535, https://doi.org/10.5194/tc-15-1517-2021, https://doi.org/10.5194/tc-15-1517-2021, 2021
Short summary
Short summary
Support Force Glacier rapidly flows into Filcher Ice Shelf of Antarctica. As we know little about this glacier and its subglacial drainage, we used seismic energy to map the transition area from grounded to floating ice where a drainage channel enters the ocean cavity. Soft sediments close to the grounding line are probably transported by this drainage channel. The constant ice thickness over the steeply dipping seabed of the ocean cavity suggests a stable transition and little basal melting.
Stefan Kowalewski, Veit Helm, Elizabeth Mary Morris, and Olaf Eisen
The Cryosphere, 15, 1285–1305, https://doi.org/10.5194/tc-15-1285-2021, https://doi.org/10.5194/tc-15-1285-2021, 2021
Short summary
Short summary
This study presents estimates of total mass input for the Pine Island Glacier (PIG) over the period 2005–2014 from airborne radar measurements. Our analysis reveals a total mass input similar to an earlier estimate for the period 1985–2009 and same area. This suggests a stationary total mass input contrary to the accelerated mass loss of PIG over the past decades. However, we also find that its uncertainty is highly sensitive to the geostatistical assumptions required for its calculation.
Mirjam Schaller, Igor Dal Bo, Todd A. Ehlers, Anja Klotzsche, Reinhard Drews, Juan Pablo Fuentes Espoz, and Jan van der Kruk
SOIL, 6, 629–647, https://doi.org/10.5194/soil-6-629-2020, https://doi.org/10.5194/soil-6-629-2020, 2020
Short summary
Short summary
In this study geophysical observations from ground-penetrating radar with pedolith physical and geochemical properties from pedons excavated in four study areas of the climate and ecological gradient in the Chilean Coastal Cordillera are combined. Findings suggest that profiles with ground-penetrating radar along hillslopes can be used to infer lateral thickness variations in pedolith horizons and to some degree physical and chemical variations with depth.
Clemens Schannwell, Reinhard Drews, Todd A. Ehlers, Olaf Eisen, Christoph Mayer, Mika Malinen, Emma C. Smith, and Hannes Eisermann
The Cryosphere, 14, 3917–3934, https://doi.org/10.5194/tc-14-3917-2020, https://doi.org/10.5194/tc-14-3917-2020, 2020
Short summary
Short summary
To reduce uncertainties associated with sea level rise projections, an accurate representation of ice flow is paramount. Most ice sheet models rely on simplified versions of the underlying ice flow equations. Due to the high computational costs, ice sheet models based on the complete ice flow equations have been restricted to < 1000 years. Here, we present a new model setup that extends the applicability of such models by an order of magnitude, permitting simulations of 40 000 years.
Alexander H. Weinhart, Johannes Freitag, Maria Hörhold, Sepp Kipfstuhl, and Olaf Eisen
The Cryosphere, 14, 3663–3685, https://doi.org/10.5194/tc-14-3663-2020, https://doi.org/10.5194/tc-14-3663-2020, 2020
Short summary
Short summary
From 1 m snow profiles along a traverse on the East Antarctic Plateau, we calculated a representative surface snow density of 355 kg m−3 for this region with an error less than 1.5 %.
This density is 10 % higher and density fluctuations seem to happen on smaller scales than climate model outputs suggest. Our study can help improve the parameterization of surface snow density in climate models to reduce the error in future sea level predictions.
Achim Heilig, Olaf Eisen, Martin Schneebeli, Michael MacFerrin, C. Max Stevens, Baptiste Vandecrux, and Konrad Steffen
The Cryosphere, 14, 385–402, https://doi.org/10.5194/tc-14-385-2020, https://doi.org/10.5194/tc-14-385-2020, 2020
Short summary
Short summary
We investigate the spatial representativeness of point observations of snow accumulation in SW Greenland. Such analyses have rarely been conducted but are necessary to link regional-scale observations from, e.g., remote-sensing data to firn cores and snow pits. The presented data reveal a low regional variability in density but snow depth can vary significantly. It is necessary to combine pits with spatial snow depth data to increase the regional representativeness of accumulation observations.
Clemens Schannwell, Reinhard Drews, Todd A. Ehlers, Olaf Eisen, Christoph Mayer, and Fabien Gillet-Chaulet
The Cryosphere, 13, 2673–2691, https://doi.org/10.5194/tc-13-2673-2019, https://doi.org/10.5194/tc-13-2673-2019, 2019
Short summary
Short summary
Ice rises are important ice-sheet features that archive the ice sheet's history in their internal structure. Here we use a 3-D numerical ice-sheet model to simulate mechanisms that lead to changes in the geometry of the internal structure. We find that changes in snowfall result in much larger and faster changes than similar changes in ice-shelf geometry. This result is integral to fully unlocking the potential of ice rises as ice-dynamic archives and potential ice-core drilling sites.
Johannes Sutter, Hubertus Fischer, Klaus Grosfeld, Nanna B. Karlsson, Thomas Kleiner, Brice Van Liefferinge, and Olaf Eisen
The Cryosphere, 13, 2023–2041, https://doi.org/10.5194/tc-13-2023-2019, https://doi.org/10.5194/tc-13-2023-2019, 2019
Short summary
Short summary
The Antarctic Ice Sheet may have played an important role in moderating the transition between warm and cold climate epochs over the last million years. We find that the Antarctic Ice Sheet grew considerably about 0.9 Myr ago, a time when ice-age–warm-age cycles changed from a
40 000 to a 100 000 year periodicity. Our findings also suggest that ice as old as 1.5 Myr still exists at the bottom of the East Antarctic Ice Sheet despite the major climate reorganisations in the past.
Anna Winter, Daniel Steinhage, Timothy T. Creyts, Thomas Kleiner, and Olaf Eisen
Earth Syst. Sci. Data, 11, 1069–1081, https://doi.org/10.5194/essd-11-1069-2019, https://doi.org/10.5194/essd-11-1069-2019, 2019
Tetsuro Taranczewski, Johannes Freitag, Olaf Eisen, Bo Vinther, Sonja Wahl, and Sepp Kipfstuhl
The Cryosphere Discuss., https://doi.org/10.5194/tc-2018-280, https://doi.org/10.5194/tc-2018-280, 2019
Preprint withdrawn
Short summary
Short summary
We used melt layers detected in ice cores from the Renland ice cap in East Greenland to find evidence of past climate trends in this region. Our record provides such information for the past 10,000 years. We developed an attempt to increase the reliability of such a record by correcting deformation-induced biases. It proves that such simple to obtain melt records can be used to gather information about paleoclimate especially for regions where climate records are sparse.
Brice Van Liefferinge, Frank Pattyn, Marie G. P. Cavitte, Nanna B. Karlsson, Duncan A. Young, Johannes Sutter, and Olaf Eisen
The Cryosphere, 12, 2773–2787, https://doi.org/10.5194/tc-12-2773-2018, https://doi.org/10.5194/tc-12-2773-2018, 2018
Short summary
Short summary
Our paper provides an important review of the state of knowledge for oldest-ice prospection, but also adds new basal geothermal heat flux constraints from recently acquired high-definition radar data sets. This is the first paper to contrast the two primary target regions for oldest ice: Dome C and Dome Fuji. Moreover, we provide statistical comparisons of all available data sets and a summary of the community's criteria for the retrieval of interpretable oldest ice since the 2013 effort.
Nanna B. Karlsson, Tobias Binder, Graeme Eagles, Veit Helm, Frank Pattyn, Brice Van Liefferinge, and Olaf Eisen
The Cryosphere, 12, 2413–2424, https://doi.org/10.5194/tc-12-2413-2018, https://doi.org/10.5194/tc-12-2413-2018, 2018
Short summary
Short summary
In this study, we investigate the probability that the Dome Fuji region in East Antarctica contains ice more than 1.5 Ma old. The retrieval of a continuous ice-core record extending beyond 1 Ma is imperative to understand why the frequency of ice ages changed from 40 to 100 ka approximately 1 Ma ago.
We use a new radar dataset to improve the ice thickness maps, and apply a thermokinematic model to predict basal temperature and age of the ice. Our results indicate several areas of interest.
Achim Heilig, Olaf Eisen, Michael MacFerrin, Marco Tedesco, and Xavier Fettweis
The Cryosphere, 12, 1851–1866, https://doi.org/10.5194/tc-12-1851-2018, https://doi.org/10.5194/tc-12-1851-2018, 2018
Short summary
Short summary
This paper presents data on temporal changes in snow and firn, which were not available before. We present data on water infiltration in the percolation zone of the Greenland Ice Sheet that improve our understanding of liquid water retention in snow and firn and mass transfer. We compare those findings with model simulations. It appears that simulated accumulation in terms of SWE is fairly accurate, while modeling of the individual parameters density and liquid water content is incorrect.
Johanna Kerch, Anja Diez, Ilka Weikusat, and Olaf Eisen
The Cryosphere, 12, 1715–1734, https://doi.org/10.5194/tc-12-1715-2018, https://doi.org/10.5194/tc-12-1715-2018, 2018
Short summary
Short summary
We investigate the effect of crystal anisotropy on seismic velocities in glacier ice by calculating seismic phase velocities using the exact c axis angles to describe the crystal orientations in ice-core samples for an alpine and a polar ice core. Our results provide uncertainty estimates for earlier established approximative calculations. Additionally, our findings highlight the variation in seismic velocity at non-vertical incidence as a function of the horizontal azimuth of the seismic plane.
Christoph Florian Schaller, Johannes Freitag, and Olaf Eisen
Clim. Past, 13, 1685–1693, https://doi.org/10.5194/cp-13-1685-2017, https://doi.org/10.5194/cp-13-1685-2017, 2017
Short summary
Short summary
In order to interpret the paleoclimatic record stored in the air enclosed in polar ice cores, it is crucial to understand the fundamental lock-in process. In our study, we present the first extensive data set of direct firn microstructure measurements and use it to show that the critical porosity of gas enclosure is independent of the climatic site conditions (such as temperature and accumulation rate). This leads to significant changes in dating and interpretation of ice-core gas records.
Sophie Berger, Reinhard Drews, Veit Helm, Sainan Sun, and Frank Pattyn
The Cryosphere, 11, 2675–2690, https://doi.org/10.5194/tc-11-2675-2017, https://doi.org/10.5194/tc-11-2675-2017, 2017
Short summary
Short summary
Floating ice shelves act as a plug for the Antarctic ice sheet. The efficiency of this ice plug depends on how and how much the ocean melts the ice from below. This study relies on satellite imagery and a Lagrangian approach to map in detail the basal mass balance of an Antarctic ice shelf. Although the large-scale melting pattern of the ice shelf agrees with previous studies, our technique successfully detects local variability (< 1 km) in the basal melting of the ice shelf.
Anna Winter, Daniel Steinhage, Emily J. Arnold, Donald D. Blankenship, Marie G. P. Cavitte, Hugh F. J. Corr, John D. Paden, Stefano Urbini, Duncan A. Young, and Olaf Eisen
The Cryosphere, 11, 653–668, https://doi.org/10.5194/tc-11-653-2017, https://doi.org/10.5194/tc-11-653-2017, 2017
Lionel Favier, Frank Pattyn, Sophie Berger, and Reinhard Drews
The Cryosphere, 10, 2623–2635, https://doi.org/10.5194/tc-10-2623-2016, https://doi.org/10.5194/tc-10-2623-2016, 2016
Short summary
Short summary
We demonstrate the short-term unstable retreat of an East Antarctic outlet glacier triggered by imposed sub-ice-shelf melt, compliant with current values, using a state-of-the-art ice-sheet model. We show that pinning points – topographic highs in contact with the ice-shelf base – have a major impact on ice-sheet stability and timing of grounding-line retreat. The study therefore calls for improving our knowledge of sub-ice-shelf bathymetry in order to reduce uncertainties in future ice loss.
Morgane Philippe, Jean-Louis Tison, Karen Fjøsne, Bryn Hubbard, Helle A. Kjær, Jan T. M. Lenaerts, Reinhard Drews, Simon G. Sheldon, Kevin De Bondt, Philippe Claeys, and Frank Pattyn
The Cryosphere, 10, 2501–2516, https://doi.org/10.5194/tc-10-2501-2016, https://doi.org/10.5194/tc-10-2501-2016, 2016
Short summary
Short summary
The reconstruction of past snow accumulation rates is crucial in the context of recent climate change and sea level rise. We measured ~ 250 years of snow accumulation using a 120 m ice core drilled in coastal East Antarctica, where such long records are very scarce. This study is the first to show an increase in snow accumulation, beginning in the 20th and particularly marked in the last 50 years, thereby confirming model predictions of increased snowfall associated with climate change.
Christoph Florian Schaller, Johannes Freitag, Sepp Kipfstuhl, Thomas Laepple, Hans Christian Steen-Larsen, and Olaf Eisen
The Cryosphere, 10, 1991–2002, https://doi.org/10.5194/tc-10-1991-2016, https://doi.org/10.5194/tc-10-1991-2016, 2016
Short summary
Short summary
Along a traverse through North Greenland in May 2015 we collected snow cores up to 2 m in depth and analyzed their properties (e.g., density). A new technique for this sampling and an adapted algorithm for comparing data sets from different positions and aligning stratigraphic features are presented. We find good agreement of the density layering in the snowpack over hundreds of kilometers. This allows the construction of a representative density profile that is statistically validated.
Reinhard Drews, Joel Brown, Kenichi Matsuoka, Emmanuel Witrant, Morgane Philippe, Bryn Hubbard, and Frank Pattyn
The Cryosphere, 10, 811–823, https://doi.org/10.5194/tc-10-811-2016, https://doi.org/10.5194/tc-10-811-2016, 2016
Short summary
Short summary
The thickness of ice shelves is typically inferred using hydrostatic equilibrium which requires knowledge of the firn density. Here, we infer density from wide-angle radar using a novel algorithm including traveltime inversion and ray tracing. We find that firn is denser inside a 2 km wide ice-shelf channel which is confirmed by optical televiewing of two boreholes. Such horizontal density variations must be accounted for when using the hydrostatic ice thickness for determining basal melt rate.
N. Wever, L. Schmid, A. Heilig, O. Eisen, C. Fierz, and M. Lehning
The Cryosphere, 9, 2271–2293, https://doi.org/10.5194/tc-9-2271-2015, https://doi.org/10.5194/tc-9-2271-2015, 2015
Short summary
Short summary
A verification of the physics based SNOWPACK model with field observations showed that typical snowpack properties like density and temperature are adequately simulated. Also two water transport schemes were verified, showing that although Richards equation improves snowpack runoff and several aspects of the internal snowpack structure, the bucket scheme appeared to have a higher agreement with the snow microstructure. The choice of water transport scheme may depend on the intended application.
R. Drews
The Cryosphere, 9, 1169–1181, https://doi.org/10.5194/tc-9-1169-2015, https://doi.org/10.5194/tc-9-1169-2015, 2015
Short summary
Short summary
Floating ice shelves extend the continental ice of Antarctica seawards and mediate ice-ocean interactions. Many ice shelves are incised with channels where basal melting is enhanced. With data and modeling it is shown how the channel geometry depends on basal melting and along-flow advection (also for channels which are not freely floating), and how channel formation imprints the general flow pattern. This opens up the opportunity to map the channel formation from surface velocities only.
A. Diez and O. Eisen
The Cryosphere, 9, 367–384, https://doi.org/10.5194/tc-9-367-2015, https://doi.org/10.5194/tc-9-367-2015, 2015
A. Diez, O. Eisen, C. Hofstede, A. Lambrecht, C. Mayer, H. Miller, D. Steinhage, T. Binder, and I. Weikusat
The Cryosphere, 9, 385–398, https://doi.org/10.5194/tc-9-385-2015, https://doi.org/10.5194/tc-9-385-2015, 2015
Related subject area
Discipline: Glaciers | Subject: Instrumentation
Brief communication: A technique for making in situ measurements at the ice–water boundary of small pieces of floating glacier ice
Spatial characterization of near-surface structure and meltwater runoff conditions across the Devon Ice Cap from dual-frequency radar reflectivity
Topology and spatial-pressure-distribution reconstruction of an englacial channel
Pressure and inertia sensing drifters for glacial hydrology flow path measurements
Hayden A. Johnson, Oskar Glowacki, Grant B. Deane, and M. Dale Stokes
The Cryosphere, 18, 265–272, https://doi.org/10.5194/tc-18-265-2024, https://doi.org/10.5194/tc-18-265-2024, 2024
Short summary
Short summary
This paper is about a way to make measurements close to small pieces of floating glacier ice. This is done by attaching instruments to the ice from a small boat. Making these measurements will be helpful for the study of the physics that goes on at small scales when glacier ice is in contact with ocean water. Understanding these small-scale physics may ultimately help improve our understanding of how much ice in Greenland and Antarctica will melt as a result of warming oceans.
Kristian Chan, Cyril Grima, Anja Rutishauser, Duncan A. Young, Riley Culberg, and Donald D. Blankenship
The Cryosphere, 17, 1839–1852, https://doi.org/10.5194/tc-17-1839-2023, https://doi.org/10.5194/tc-17-1839-2023, 2023
Short summary
Short summary
Climate warming has led to more surface meltwater produced on glaciers that can refreeze in firn to form ice layers. Our work evaluates the use of dual-frequency ice-penetrating radar to characterize these ice layers on the Devon Ice Cap. Results indicate that they are meters thick and widespread, and thus capable of supporting lateral meltwater runoff from the top of ice layers. We find that some of this meltwater runoff could be routed through supraglacial rivers in the ablation zone.
Laura Piho, Andreas Alexander, and Maarja Kruusmaa
The Cryosphere, 16, 3669–3683, https://doi.org/10.5194/tc-16-3669-2022, https://doi.org/10.5194/tc-16-3669-2022, 2022
Short summary
Short summary
In this study we develop a novel method to map subsurface water flow paths and spatially reference in situ data from such environments. We demonstrate the feasibility of our method with the reconstruction of the flow path of an englacial channel and the water pressures therein. Our method opens up for direct mapping of subsurface water flow paths, not only in glacier hydrology but also in other applications (e.g., karst caves, pipelines, sewer systems).
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.
Cited articles
Alean, J., Haeberli, W., and Schädler, B.: Snow Accumulation, Firn Temperature and Solar Radiation in the Area of the Colle Gnifetti Core Drilling Site (Monte Rosa, Swiss Alps): Distribution Patterns and Interrelationships, Zeitschrift für Gletscherkunde und Glazialgeologie, 19, 131–147, 1983. a
Arthern, R. J., J. Corr, H. F., Gillet-Chaulet, F., Hawley, R. L., and Morris, E. M.: Inversion for the Density-depth Profile of Polar Firn Using a Stepped-frequency Radar, J. Geophys. Res.-Earth, 118, 1257–1263, https://doi.org/10.1002/jgrf.20089, 2013. a
Bohleber, P.: Ground-Penetrating Radar Assisted Ice Core Research: The Challenge of Alpine Glaciers and Dielectric Ice Properties, PhD thesis, Heidelberg University, https://doi.org/10.11588/heidok.00012800, 2011. a, b, c
Bohleber, P., Wagner, N., and Eisen, O.: Permittivity of Ice at Radio Frequencies: Part II. Artificial and Natural Polycrystalline Ice, Cold Reg. Sci. Technol., 83–84, 13–19, https://doi.org/10.1016/j.coldregions.2012.05.010, 2012. a
Bohleber, P., Erhardt, T., Spaulding, N., Hoffmann, H., Fischer, H., and Mayewski, P.: Temperature and mineral dust variability recorded in two low-accumulation Alpine ice cores over the last millennium, Clim. Past, 14, 21–37, https://doi.org/10.5194/cp-14-21-2018, 2018. a
Case, E. and Kingslake, J.: Phase-Sensitive Radar as a Tool for Measuring Firn Compaction, J. Glaciol., 68, 139–152, https://doi.org/10.1017/jog.2021.83, 2022. a
Castelletti, D., Schroeder, D. M., Hensley, S., Grima, C., Ng, G., Young, D., Gim, Y., Bruzzone, L., Moussessian, A., and Blankenship, D. D.: An Interferometric Approach to Cross-Track Clutter Detection in Two-Channel VHF Radar Sounders, IEEE T. Geosci. Remote, 55, 6128–6140, https://doi.org/10.1109/TGRS.2017.2721433, 2017. a, b
Cavitte, M. G. P., Parrenin, F., Ritz, C., Young, D. A., Van Liefferinge, B., Blankenship, D. D., Frezzotti, M., and Roberts, J. L.: Accumulation patterns around Dome C, East Antarctica, in the last 73 kyr, The Cryosphere, 12, 1401–1414, https://doi.org/10.5194/tc-12-1401-2018, 2018. a
Clifford, H. M., Spaulding, N. E., Kurbatov, A. V., More, A., Korotkikh, E. V., Sneed, S. B., Handley, M., Maasch, K. A., Loveluck, C. P., Chaplin, J., McCormick, M., and Mayewski, P. A.: A 2000 Year Saharan Dust Event Proxy Record from an Ice Core in the European Alps, J. Geophys. Res.-Atmos., 124, 12882–12900, https://doi.org/10.1029/2019JD030725, 2019. a
Diez, A., Eisen, O., Hofstede, C., Bohleber, P., and Polom, U.: Joint Interpretation of Explosive and Vibroseismic Surveys on Cold Firn for the Investigation of Ice Properties, Ann. Glaciol., 54, 201–210, https://doi.org/10.3189/2013AoG64A200, 2013. a
Drews, R.: Evolution of ice-shelf channels in Antarctic ice shelves, The Cryosphere, 9, 1169–1181, https://doi.org/10.5194/tc-9-1169-2015, 2015. a
Drews, R., Eisen, O., Weikusat, I., Kipfstuhl, S., Lambrecht, A., Steinhage, D., Wilhelms, F., and Miller, H.: Layer disturbances and the radio-echo free zone in ice sheets, The Cryosphere, 3, 195–203, https://doi.org/10.5194/tc-3-195-2009, 2009. a
Drews, R., Eisen, O., Steinhage, D., Weikusat, I., Kipfstuhl, S., and Wilhelms, F.: Potential Mechanisms for Anisotropy in Ice-Penetrating Radar Data, J. Glaciol., 58, 613–624, https://doi.org/10.3189/2012JoG11J114, 2012. a, b
EPICA community members: Eight Glacial Cycles from an Antarctic Ice Core, Nature, 429, 623–628, https://doi.org/10.1038/nature02599, 2004. a
Ershadi, M. R., Drews, R., Martín, C., Eisen, O., Ritz, C., Corr, H., Christmann, J., Zeising, O., Humbert, A., and Mulvaney, R.: Polarimetric radar reveals the spatial distribution of ice fabric at domes and divides in East Antarctica, The Cryosphere, 16, 1719–1739, https://doi.org/10.5194/tc-16-1719-2022, 2022. a
Ershadi, M. R., Drews, R., Hawkins, J., Elliott, J., Lines, A. P., Koch, I., and Eisen, O.: Autonomous Rover Enables Radar Profiling of Ice-Fabric Properties in Antarctica, IEEE T. Geosci. Remote, 62, 5913809, https://doi.org/10.1109/TGRS.2024.3394594, 2024. a, b
Freitag, J., Kerch, J., Hoffmann, H., Spaulding, N., and Bohleber, P.: XCT Density from the Alpine Ice Core KCC (2013), PANGAEA [data set], https://doi.org/10.1594/PANGAEA.887691, 2018. a, b, c
Fujita, S., Maeno, H., and Matsuoka, K.: Radio-Wave Depolarization and Scattering within Ice Sheets: A Matrix-Based Model to Link Radar and Ice-Core Measurements and Its Application, J. Glaciol., 52, 407–424, https://doi.org/10.3189/172756506781828548, 2006. a
Gabrieli, J. and Barbante, C.: The Alps in the Age of the Anthropocene: The Impact of Human Activities on the Cryosphere Recorded in the Colle Gnifetti Glacier, Rendiconti Lincei, 25, 71–83, https://doi.org/10.1007/s12210-014-0292-2, 2014. a
Gillet-Chaulet, F., Hindmarsh, R. C. A., Corr, H. F. J., King, E. C., and Jenkins, A.: In-Situ Quantification of Ice Rheology and Direct Measurement of the Raymond Effect at Summit, Greenland Using a Phase-Sensitive Radar, Geophys. Res. Lett., 38, L24503, https://doi.org/10.1029/2011GL049843, 2011. a
Hati, A., Nelson, C. W., and Howe, D. A.: Vibration-Induced PM and AM Noise in Microwave Components, IEEE T. Ultrason. Ferr., 56, 2050–2059, https://doi.org/10.1109/TUFFC.2009.1288, 2009. a
Heister, A. and Scheiber, R.: Coherent large beamwidth processing of radio-echo sounding data, The Cryosphere, 12, 2969–2979, https://doi.org/10.5194/tc-12-2969-2018, 2018. a
Hélière, F., Lin, C.-C., Corr, H., and Vaughan, D.: Radio Echo Sounding of Pine Island Glacier, West Antarctica: Aperture Synthesis Processing and Analysis of Feasibility from Space, IEEE T. Geosci. Remote, 45, 2573–2582, https://doi.org/10.1109/TGRS.2007.897433, 2007. a
Hoelzle, M., Darms, G., Lüthi, M. P., and Suter, S.: Evidence of accelerated englacial warming in the Monte Rosa area, Switzerland/Italy, The Cryosphere, 5, 231–243, https://doi.org/10.5194/tc-5-231-2011, 2011. a
Hoffmann, H., Preunkert, S., Legrand, M., Leinfelder, D., Bohleber, P., Friedrich, R., and Wagenbach, D.: A New Sample Preparation System for Micro-14C Dating of Glacier Ice with a First Application to a High Alpine Ice Core from Colle Gnifetti (Switzerland), Radiocarbon, 60, 517–533, https://doi.org/10.1017/RDC.2017.99, 2018. a
Holschuh, N., Christianson, K., and Anandakrishnan, S.: Power Loss in Dipping Internal Reflectors, Imaged Using Ice-Penetrating Radar, Ann. Glaciol., 55, 49–56, https://doi.org/10.3189/2014AoG67A005, 2014. a, b
Holschuh, N., Parizek, B. R., Alley, R. B., and Anandakrishnan, S.: Decoding Ice Sheet Behavior Using Englacial Layer Slopes, Geophys. Res. Lett., 44, 5561–5570, https://doi.org/10.1002/2017GL073417, 2017. a, b
Holschuh, N., Christianson, K., Paden, J., Alley, R., and Anandakrishnan, S.: Linking Postglacial Landscapes to Glacier Dynamics Using Swath Radar at Thwaites Glacier, Antarctica, Geology, 48, 268–272, https://doi.org/10.1130/G46772.1, 2020. a, b
Jenk, T. M., Szidat, S., Bolius, D., Sigl, M., Gäggeler, H. W., Wacker, L., Ruff, M., Barbante, C., Boutron, C. F., and Schwikowski, M.: A Novel Radiocarbon Dating Technique Applied to an Ice Core from the Alps Indicating Late Pleistocene Ages, J. Geophys. Res.-Atmos., 114, 2009JD011860, https://doi.org/10.1029/2009JD011860, 2009. a, b, c, d, e
Jordan, T. M., Schroeder, D. M., Elsworth, C. W., and Siegfried, M. R.: Estimation of Ice Fabric within Whillans Ice Stream Using Polarimetric Phase-Sensitive Radar Sounding, Ann. Glaciol., 61, 74–83, https://doi.org/10.1017/aog.2020.6, 2020. a
Kapai, S., Schroeder, D., Broome, A., Young, T. J., and Stewart, C.: SAR Focusing of Mobile ApRES Surveys, in: IGARSS 2022 – 2022 IEEE International Geoscience and Remote Sensing Symposium, IEEE, Kuala Lumpur, Malaysia, 17–22 July 2022, 1688–1691, ISBN 978-1-66542-792-0, https://doi.org/10.1109/IGARSS46834.2022.9883784, 2022. a, b, c, d
Karlsson, N. B., Dahl-Jensen, D., Gogineni, S. P., and Paden, J. D.: Tracing the Depth of the Holocene Ice in North Greenland from Radio-Echo Sounding Data, Ann. Glaciol., 54, 44–50, https://doi.org/10.3189/2013AoG64A057, 2013. a
Kerch, J. K.: Crystal-Orientation Fabric Variations on the Cm-Scale in Cold Alpine Ice: Interaction with Paleo-Climate Proxies under Deformation and Implications for the Interpretation of Seismic Velocities, PhD thesis, Heidelberg University, https://doi.org/10.11588/heidok.00022326, 2016. a
Kingslake, J., Hindmarsh, R. C. A., Aðalgeirsdóttir, G., Conway, H., Corr, H. F. J., Gillet-Chaulet, F., Martín, C., King, E. C., Mulvaney, R., and Pritchard, H. D.: Full-Depth Englacial Vertical Ice Sheet Velocities Measured Using Phase-Sensitive Radar: Measuring Englacial Ice Velocities, J. Geophys. Res.-Earth, 119, 2604–2618, https://doi.org/10.1002/2014JF003275, 2014. a
Koch, I., Drews, R., Franke, S., Jansen, D., Oraschewski, F. M., Muhle, L. S., Višnjević, V., Matsuoka, K., Pattyn, F., and Eisen, O.: Radar Internal Reflection Horizons from Multisystem Data Reflect Ice Dynamic and Surface Accumulation History along the Princess Ragnhild Coast, Dronning Maud Land, East Antarctica, J. Glaciol., 1–19, https://doi.org/10.1017/jog.2023.93, 2023. a
Konrad, H., Bohleber, P., Wagenbach, D., Vincent, C., and Eisen, O.: Determining the Age Distribution of Colle Gnifetti, Monte Rosa, Swiss Alps, by Combining Ice Cores, Ground-Penetrating Radar and a Simple Flow Model, J. Glaciol., 59, 179–189, https://doi.org/10.3189/2013JoG12J072, 2013. a, b, c, d, e, f, g, h
Koutnik, M. R., Fudge, T. J., Conway, H., Waddington, E. D., Neumann, T. A., Cuffey, K. M., Buizert, C., and Taylor, K. C.: Holocene Accumulation and Ice Flow near the West Antarctic Ice Sheet Divide Ice Core Site, J. Geophys. Res.-Earth, 121, 907–924, https://doi.org/10.1002/2015JF003668, 2016. a
Kusk, A. and Dall, J.: SAR Focusing of P-band Ice Sounding Data Using Back-Projection, in: 2010 IEEE International Geoscience and Remote Sensing Symposium, IEEE, Honolulu, HI, USA, 25–30 July 2010, 4071–4074, ISBN 978-1-4244-9565-8, https://doi.org/10.1109/IGARSS.2010.5651038, 2010. a
Licciulli, C., Bohleber, P., Lier, J., Gagliardini, O., Hoelzle, M., and Eisen, O.: A Full Stokes Ice-Flow Model to Assist the Interpretation of Millennial-Scale Ice Cores at the High-Alpine Drilling Site Colle Gnifetti, Swiss/Italian Alps, J. Glaciol., 66, 35–48, https://doi.org/10.1017/jog.2019.82, 2020. a
Lilien, D. A., Steinhage, D., Taylor, D., Parrenin, F., Ritz, C., Mulvaney, R., Martín, C., Yan, J.-B., O'Neill, C., Frezzotti, M., Miller, H., Gogineni, P., Dahl-Jensen, D., and Eisen, O.: Brief communication: New radar constraints support presence of ice older than 1.5 Myr at Little Dome C, The Cryosphere, 15, 1881–1888, https://doi.org/10.5194/tc-15-1881-2021, 2021. a
Looyenga, H.: Dielectric Constants of Heterogeneous Mixtures, Physica, 31, 401–406, https://doi.org/10.1016/0031-8914(65)90045-5, 1965. a
Lüthi, M. and Funk, M.: Dating Ice Cores from a High Alpine Glacier with a Flow Model for Cold Firn, Ann. Glaciol., 31, 69–79, https://doi.org/10.3189/172756400781820381, 2000. a
MacGregor, J. A., Fahnestock, M. A., Catania, G. A., Paden, J. D., Prasad Gogineni, S., Young, S. K., Rybarski, S. C., Mabrey, A. N., Wagman, B. M., and Morlighem, M.: Radiostratigraphy and Age Structure of the Greenland Ice Sheet, J. Geophys. Res.-Earth, 120, 212–241, https://doi.org/10.1002/2014JF003215, 2015. a, b, c, d
Medley, B., Ligtenberg, S., Joughin, I., Van Den Broeke, M., Gogineni, S., and Nowicki, S.: Antarctic Firn Compaction Rates from Repeat-Track Airborne Radar Data: I. Methods, Ann. Glaciol., 56, 155–166, https://doi.org/10.3189/2015AoG70A203, 2015. a
Moran, M. L., Greenfield, R. J., Arcone, S. A., and Delaney, A. J.: Delineation of a Complexly Dipping Temperate Glacier Bed Using Short-Pulse Radar Arrays, J. Glaciol., 46, 274–286, https://doi.org/10.3189/172756500781832882, 2000. a
NASA Shuttle Radar Topography Mission: Shuttle Radar Topography Mission (SRTM) Global, OpenTopography [data set], https://doi.org/10.5069/G9445JDF, 2013. a
NEEM community members: Eemian Interglacial Reconstructed from a Greenland Folded Ice Core, Nature, 493, 489–494, https://doi.org/10.1038/nature11789, 2013. a
Nicholls, K. W., Corr, H. F., Stewart, C. L., Lok, L. B., Brennan, P. V., and Vaughan, D. G.: A Ground-Based Radar for Measuring Vertical Strain Rates and Time-Varying Basal Melt Rates in Ice Sheets and Shelves, J. Glaciol., 61, 1079–1087, https://doi.org/10.3189/2015JoG15J073, 2015. a, b
Oraschewski, F. M., Koch, I., Ershadi, M. R., Hawkins, J., Eisen, O., and Drews, R.: Raw Data of Mobile Phase-Sensitive Radio Echo Sounder (pRES) Profiling Data of Deep Radiostratigraphy of Colle Gnifetti (Swiss–Italian Alps), 2021, PANGAEA [data set], https://doi.org/10.1594/PANGAEA.965199, 2024a. a
Oraschewski, F. M., Koch, I., Ershadi, M. R., Hawkins, J., Eisen, O., and Drews, R.: Mobile Phase-Sensitive Radio Echo Sounder (pRES) Profiling Data of Deep Radiostratigraphy of Colle Gnifetti (Swiss–Italian Alps), 2021, PANGAEA [data set], https://doi.org/10.1594/PANGAEA.965194, 2024b. a
Oraschewski, F.: Oraschewski/pRocESsor: pRocESsor – For Layer-Optimized SAR Processing of Mobile pRES Profiles, Zenodo [code], https://doi.org/10.5281/zenodo.12656458, 2024c. a
Paden, J.: Synthetic Aperture Radar for Imaging the Basal Conditions of the Polar Ice Sheets, PhD thesis, University of Kansas, https://web.archive.org/web/20170808175054id_/https://people.cresis.ku.edu/~paden/padenDissertation.pdf (last access: 21 August 2024), 2006. a
Peters, M. E., Blankenship, D. D., and Morse, D. L.: Analysis Techniques for Coherent Airborne Radar Sounding: Application to West Antarctic Ice Streams, J. Geophys. Res.-Sol. Ea., 110, 2004JB003222, https://doi.org/10.1029/2004JB003222, 2005. a
Peters, M. E., Blankenship, D., Carter, S., Kempf, S., Young, D., and Holt, J.: Along-Track Focusing of Airborne Radar Sounding Data from West Antarctica for Improving Basal Reflection Analysis and Layer Detection, IEEE T. Geosci. Remote, 45, 2725–2736, https://doi.org/10.1109/TGRS.2007.897416, 2007. a
Pickell, D. J. and Hawley, R. L.: Performance Characterization of a New, Low-Cost Multi-GNSS Instrument for the Cryosphere, J. Glaciol., 1–7, https://doi.org/10.1017/jog.2023.97, 2024. a
Preunkert, S., Wagenbach, D., and Legrand, M.: A Seasonally Resolved Alpine Ice Core Record of Nitrate: Comparison with Anthropogenic Inventories and Estimation of Preindustrial Emissions of NO in Europe, J. Geophys. Res.-Atmos., 108, 2003JD003475, https://doi.org/10.1029/2003JD003475, 2003. a
Scanlan, K. M., Rutishauser, A., Young, D. A., and Blankenship, D. D.: Interferometric Discrimination of Cross-Track Bed Clutter in Ice-Penetrating Radar Sounding Data, Ann. Glaciol., 61, 68–73, https://doi.org/10.1017/aog.2020.20, 2020. a, b
Schroeder, D. M., Castelletti, D., and Pena, I.: Revisting the Limits of Azimuth Processing Gain for Radar Sounding, in: IGARSS 2019 – 2019 IEEE International Geoscience and Remote Sensing Symposium, IEEE, Yokohama, Japan, 28 July–2 August 2019. 994–996, ISBN 978-1-5386-9154-0, https://doi.org/10.1109/IGARSS.2019.8898737, 2019. a
Schwikowski, B. M., Doscher, A., Gaggeler, H., and Schotterer, U.: Anthropogenic versus Natural Sources of Atmospheric Sulphate from an Alpine Ice Core, Tellus B, 51, 938–951, https://doi.org/10.1034/j.1600-0889.1999.t01-4-00006.x, 1999. a
Shi, L., Allen, C. T., Ledford, J. R., Rodriguez-Morales, F., Blake, W. A., Panzer, B. G., Prokopiack, S. C., Leuschen, C. J., and Gogineni, S.: Multichannel Coherent Radar Depth Sounder for NASA Operation Ice Bridge, in: 2010 IEEE International Geoscience and Remote Sensing Symposium, IEEE, Honolulu, HI, USA, 25–30 July 2010, 1729–1732, ISBN 978-1-4244-9565-8, https://doi.org/10.1109/IGARSS.2010.5649518, 2010. a
Sigl, M., Abram, N. J., Gabrieli, J., Jenk, T. M., Osmont, D., and Schwikowski, M.: 19th century glacier retreat in the Alps preceded the emergence of industrial black carbon deposition on high-alpine glaciers, The Cryosphere, 12, 3311–3331, https://doi.org/10.5194/tc-12-3311-2018, 2018a. a, b, c, d, e, f, g, h, i
Sigl, M., Abram, N. J., Gabrieli, J., Jenk, T. M., Osmont, D., and Schwikowski, M.: Black Carbon (rBC), Bismuth, Lead and Others from 1741 to 2015 AD from Colle Gnifetti Ice Core (Swiss/Italian Alps), PANGAEA [data set], https://doi.org/10.1594/PANGAEA.894788, 2018b. a, b, c, d
Still, H., Odolinski, R., Bowman, M. H., Hulbe, C., and Prior, D. J.: Observing Glacier Dynamics with Low-Cost, Multi-GNSS Positioning in Victoria Land, Antarctica, J. Glaciol., 1–18, https://doi.org/10.1017/jog.2023.101, 2023. a
Vaňková, I., Nicholls, K. W., Xie, S., Parizek, B. R., Voytenko, D., and Holland, D. M.: Depth-Dependent Artifacts Resulting from ApRES Signal Clipping, Ann. Glaciol., 61, 108–113, https://doi.org/10.1017/aog.2020.56, 2020. a
Vaňková, I., Cook, S., Winberry, J. P., Nicholls, K. W., and Galton-Fenzi, B. K.: Deriving Melt Rates at a Complex Ice Shelf Base Using in Situ Radar: Application to Totten Ice Shelf, Geophys. Res. Lett., 48, e2021GL092 692, https://doi.org/10.1029/2021GL092692, 2021. a, b
Wagenbach, D., Bohleber, P., and Preunkert, S.: Cold, Alpine Ice Bodies Revisited: What May We Learn from Their Impurity and Isotope Content?, Geogr. Ann. A, 94, 245–263, https://doi.org/10.1111/j.1468-0459.2012.00461.x, 2012. a
Xu, B., Lang, S., Cui, X., Li, L., Liu, X., Guo, J., and Sun, B.: Focused Synthetic Aperture Radar Processing of Ice-Sounding Data Collected over East Antarctic Ice Sheet via Spatial-Correlation-Based Algorithm Using Fast Back Projection, IEEE T. Geosci. Remote, 60, 5233009, https://doi.org/10.1109/TGRS.2022.3198432, 2022. a
Zeising, O., Steinhage, D., Nicholls, K. W., Corr, H. F. J., Stewart, C. L., and Humbert, A.: Basal melt of the southern Filchner Ice Shelf, Antarctica, The Cryosphere, 16, 1469–1482, https://doi.org/10.5194/tc-16-1469-2022, 2022. a, b
Short summary
Mountain glaciers have a layered structure which contains information about past snow accumulation and ice flow. Using ground-penetrating radar instruments, the internal structure can be observed. The detection of layers in the deeper parts of a glacier is often difficult. Here, we present a new approach for imaging the englacial structure of an Alpine glacier (Colle Gnifetti, Switzerland and Italy) using a phase-sensitive radar that can detect reflection depth changes at sub-wavelength scales.
Mountain glaciers have a layered structure which contains information about past snow...
