Articles | Volume 18, issue 2
https://doi.org/10.5194/tc-18-775-2024
© 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-18-775-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
20 Feb 2024
Research article |
| 20 Feb 2024
| 20 Feb 2024
Globally consistent estimates of high-resolution Antarctic ice mass balance and spatially resolved glacial isostatic adjustment
Matthias O. Willen
CORRESPONDING AUTHOR
Institut für Planetare Geodäsie, Technische Universität Dresden, Dresden, Germany
Martin Horwath
Institut für Planetare Geodäsie, Technische Universität Dresden, Dresden, Germany
Eric Buchta
Institut für Planetare Geodäsie, Technische Universität Dresden, Dresden, Germany
Mirko Scheinert
Institut für Planetare Geodäsie, Technische Universität Dresden, Dresden, Germany
Veit Helm
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
Bernd Uebbing
Institute of Geodesy and Geoinformation, University of Bonn, Bonn, Germany
Jürgen Kusche
Institute of Geodesy and Geoinformation, University of Bonn, Bonn, Germany
Related authors
Matthias O. Willen, Bert Wouters, Taco Broerse, Eric Buchta, and Veit Helm
EGUsphere, https://doi.org/10.5194/egusphere-2024-3086, https://doi.org/10.5194/egusphere-2024-3086, 2024
Short summary
Short summary
Collapse of the West Antarctic ice sheet in the Amundsen Sea Embayment is likely in the near future. Vertical uplift of bedrock due to glacial isostatic adjustment stabilizes the ice sheet and may delay its collapse. So far, only spatially and temporally sparse GNSS measurements have been able to observe this bedrock motion. We have combined satellite data and quantified a region-wide bedrock motion that independently matches GNSS measurements. This can improve ice-sheet predictions.
Maria T. Kappelsberger, Martin Horwath, Eric Buchta, Matthias O. Willen, Ludwig Schröder, Sanne B. M. Veldhuijsen, Peter Kuipers Munneke, and Michiel R. van den Broeke
The Cryosphere, 18, 4355–4378, https://doi.org/10.5194/tc-18-4355-2024, https://doi.org/10.5194/tc-18-4355-2024, 2024
Short summary
Short summary
The interannual variations in the height of the Antarctic Ice Sheet (AIS) are mainly due to natural variations in snowfall. Precise knowledge of these variations is important for the detection of any long-term climatic trends in AIS surface elevation. We present a new product that spatially resolves these height variations over the period 1992–2017. The product combines the strengths of atmospheric modeling results and satellite altimetry measurements.
Matthias O. Willen, Martin Horwath, Ludwig Schröder, Andreas Groh, Stefan R. M. Ligtenberg, Peter Kuipers Munneke, and Michiel R. van den Broeke
The Cryosphere, 14, 349–366, https://doi.org/10.5194/tc-14-349-2020, https://doi.org/10.5194/tc-14-349-2020, 2020
Katrina Lutz, Lily Bever, Christian Sommer, Thorsten Seehaus, Angelika Humbert, Mirko Scheinert, and Matthias Braun
The Cryosphere, 18, 5431–5449, https://doi.org/10.5194/tc-18-5431-2024, https://doi.org/10.5194/tc-18-5431-2024, 2024
Short summary
Short summary
The estimation of the amount of water found within supraglacial lakes is important for understanding how much water is lost from glaciers each year. Here, we develop two new methods for estimating supraglacial lake volume that can be easily applied on a large scale. Furthermore, we compare these methods to two previously developed methods in order to determine when it is best to use each method. Finally, three of these methods are applied to peak melt dates over an area in Northeast Greenland.
Shfaqat A. Khan, Helene Seroussi, Mathieu Morlighem, William Colgan, Veit Helm, Gong Cheng, Danjal Berg, Valentina R. Barletta, Nicolaj K. Larsen, William Kochtitzky, Michiel van den Broeke, Kurt H. Kjær, Andy Aschwanden, Brice Noël, Jason E. Box, Joseph A. MacGregor, Robert S. Fausto, Kenneth D. Mankoff, Ian M. Howat, Kuba Oniszk, Dominik Fahrner, Anja Løkkegaard, Eigil Y. H. Lippert, and Javed Hassan
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2024-348, https://doi.org/10.5194/essd-2024-348, 2024
Preprint under review for ESSD
Short summary
Short summary
The surface elevation of the Greenland Ice Sheet is changing due to surface mass balance processes and ice dynamics, each exhibiting distinct spatiotemporal patterns. Here, we employ satellite and airborne altimetry data with fine spatial (1 km) and temporal (monthly) resolutions to document this spatiotemporal evolution from 2003 to 2023. This dataset of fine-resolution altimetry data in both space and time will support studies of ice mass loss and useful for GIS ice sheet modelling.
Matthias O. Willen, Bert Wouters, Taco Broerse, Eric Buchta, and Veit Helm
EGUsphere, https://doi.org/10.5194/egusphere-2024-3086, https://doi.org/10.5194/egusphere-2024-3086, 2024
Short summary
Short summary
Collapse of the West Antarctic ice sheet in the Amundsen Sea Embayment is likely in the near future. Vertical uplift of bedrock due to glacial isostatic adjustment stabilizes the ice sheet and may delay its collapse. So far, only spatially and temporally sparse GNSS measurements have been able to observe this bedrock motion. We have combined satellite data and quantified a region-wide bedrock motion that independently matches GNSS measurements. This can improve ice-sheet predictions.
Eric Buchta, Mirko Scheinert, Matt A. King, Terry Wilson, Achraf Koulali, Peter J. Clarke, Demián Gómez, Eric Kendrick, Christoph Knöfel, and Peter Busch
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2024-355, https://doi.org/10.5194/essd-2024-355, 2024
Preprint under review for ESSD
Short summary
Short summary
For nearly three decades, geodetic GPS measurements in Antarctica have tracked bedrock displacement, vital for understanding geodynamic processes like plate motion and glacial isostatic adjustment (GIA). However, the potential of GPS data has been limited by its partially fragmented availability and unreliable metadata. A new dataset, spanning 1995–2021, offers consistently processed coordinate time series for 286 GPS sites, promising to enhance future geodynamic research.
Maria T. Kappelsberger, Martin Horwath, Eric Buchta, Matthias O. Willen, Ludwig Schröder, Sanne B. M. Veldhuijsen, Peter Kuipers Munneke, and Michiel R. van den Broeke
The Cryosphere, 18, 4355–4378, https://doi.org/10.5194/tc-18-4355-2024, https://doi.org/10.5194/tc-18-4355-2024, 2024
Short summary
Short summary
The interannual variations in the height of the Antarctic Ice Sheet (AIS) are mainly due to natural variations in snowfall. Precise knowledge of these variations is important for the detection of any long-term climatic trends in AIS surface elevation. We present a new product that spatially resolves these height variations over the period 1992–2017. The product combines the strengths of atmospheric modeling results and satellite altimetry measurements.
Veit Helm, Alireza Dehghanpour, Ronny Hänsch, Erik Loebel, Martin Horwath, and Angelika Humbert
The Cryosphere, 18, 3933–3970, https://doi.org/10.5194/tc-18-3933-2024, https://doi.org/10.5194/tc-18-3933-2024, 2024
Short summary
Short summary
We present a new approach (AWI-ICENet1), based on a deep convolutional neural network, for analysing satellite radar altimeter measurements to accurately determine the surface height of ice sheets. Surface height estimates obtained with AWI-ICENet1 (along with related products, such as ice sheet height change and volume change) show improved and unbiased results compared to other products. This is important for the long-term monitoring of ice sheet mass loss and its impact on sea level rise.
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.
Christoph Dahle, Eva Boergens, Ingo Sasgen, Thorben Döhne, Sven Reißland, Henryk Dobslaw, Volker Klemann, Michael Murböck, Rolf König, Robert Dill, Mike Sips, Ulrike Sylla, Andreas Groh, Martin Horwath, and Frank Flechtner
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2024-347, https://doi.org/10.5194/essd-2024-347, 2024
Revised manuscript accepted for ESSD
Short summary
Short summary
The satellite missions GRACE and GRACE-FO are unique observing systems to quantify global mass changes at the Earth’s surface from space. Time series of these mass changes are of high value for various applications, e.g., in hydrology, glaciology, and oceanography. GravIS provides easy access to user-friendly, regularly updated mass anomaly products. The associated portal visualizes and describes these data, aiming to highlight their significance for understanding changes in the climate system.
Lara Börger, Michael Schindelegger, Mengnan Zhao, Rui M. Ponte, Anno Löcher, Bernd Uebbing, Jean-Marc Molines, and Thierry Penduff
Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2024-21, https://doi.org/10.5194/esd-2024-21, 2024
Revised manuscript accepted for ESD
Short summary
Short summary
Flows in the ocean are driven either by atmospheric forces or by small-scale internal disturbances that are inherently chaotic. We use computer simulation results to show that these chaotic oceanic disturbances can attain spatial scales large enough to alter the motion of Earth’s pole of rotation. Given their size and unpredictable nature, the chaotic signals are a source of uncertainty when interpreting observed year-to-year polar motion changes in terms of other processes in the Earth system.
Erik Loebel, Mirko Scheinert, Martin Horwath, Angelika Humbert, Julia Sohn, Konrad Heidler, Charlotte Liebezeit, and Xiao Xiang Zhu
The Cryosphere, 18, 3315–3332, https://doi.org/10.5194/tc-18-3315-2024, https://doi.org/10.5194/tc-18-3315-2024, 2024
Short summary
Short summary
Comprehensive datasets of calving-front changes are essential for studying and modeling outlet glaciers. Current records are limited in temporal resolution due to manual delineation. We use deep learning to automatically delineate calving fronts for 23 glaciers in Greenland. Resulting time series resolve long-term, seasonal, and subseasonal patterns. We discuss the implications of our results and provide the cryosphere community with a data product and an implementation of our processing system.
Angelika Humbert, Veit Helm, Ole Zeising, Niklas Neckel, Matthias H. Braun, Shfaqat Abbas Khan, Martin Rückamp, Holger Steeb, Julia Sohn, Matthias Bohnen, and Ralf Müller
EGUsphere, https://doi.org/10.5194/egusphere-2024-1151, https://doi.org/10.5194/egusphere-2024-1151, 2024
Short summary
Short summary
We study the evolution of a massive lake on the Greenland Ice Sheet using satellite and airborne data and some modelling. The lake is emptying rapidly. The water flows to the base of the glacier through cracks and gullies that remain visible over years. Some of them become reactive. We find features inside the glacier that stem from the drainage events with even 1 km width. These features are persistent over the years, although they are changing in shape.
Petra Döll, Howlader Mohammad Mehedi Hasan, Kerstin Schulze, Helena Gerdener, Lara Börger, Somayeh Shadkam, Sebastian Ackermann, Seyed-Mohammad Hosseini-Moghari, Hannes Müller Schmied, Andreas Güntner, and Jürgen Kusche
Hydrol. Earth Syst. Sci., 28, 2259–2295, https://doi.org/10.5194/hess-28-2259-2024, https://doi.org/10.5194/hess-28-2259-2024, 2024
Short summary
Short summary
Currently, global hydrological models do not benefit from observations of model output variables to reduce and quantify model output uncertainty. For the Mississippi River basin, we explored three approaches for using both streamflow and total water storage anomaly observations to adjust the parameter sets in a global hydrological model. We developed a method for considering the observation uncertainties to quantify the uncertainty of model output and provide recommendations.
Torsten Kanzow, Angelika Humbert, Thomas Mölg, Mirko Scheinert, Matthias Braun, Hans Burchard, Francesca Doglioni, Philipp Hochreuther, Martin Horwath, Oliver Huhn, Jürgen Kusche, Erik Loebel, Katrina Lutz, Ben Marzeion, Rebecca McPherson, Mahdi Mohammadi-Aragh, Marco Möller, Carolyne Pickler, Markus Reinert, Monika Rhein, Martin Rückamp, Janin Schaffer, Muhammad Shafeeque, Sophie Stolzenberger, Ralph Timmermann, Jenny Turton, Claudia Wekerle, and Ole Zeising
EGUsphere, https://doi.org/10.5194/egusphere-2024-757, https://doi.org/10.5194/egusphere-2024-757, 2024
Short summary
Short summary
The Greenland Ice Sheet represents the second-largest contributor to global sea-level rise. We quantify atmosphere, ice and ocean-based processes related to the mass balance of glaciers in Northeast Greenland, focusing on Greenland’s largest floating ice tongue, the 79N Glacier. We find that together, the different in situ and remote sensing observations and model simulations to reveal a consistent picture of a coupled atmosphere-ice sheet-ocean system, that has entered a phase of major change.
Ole Zeising, Niklas Neckel, Nils Dörr, Veit Helm, Daniel Steinhage, Ralph Timmermann, and Angelika Humbert
The Cryosphere, 18, 1333–1357, https://doi.org/10.5194/tc-18-1333-2024, https://doi.org/10.5194/tc-18-1333-2024, 2024
Short summary
Short summary
The 79° North Glacier in Greenland has experienced significant changes over the last decades. Due to extreme melt rates, the ice has thinned significantly in the vicinity of the grounding line, where a large subglacial channel has formed since 2010. We attribute these changes to warm ocean currents and increased subglacial discharge from surface melt. However, basal melting has decreased since 2018, indicating colder water inflow into the cavity below the glacier.
Reinhard Dietrich, Christoph Knöfel, Mirko Scheinert, and Ralf Rosenau
Polarforschung, 92, 1–13, https://doi.org/10.5194/polf-92-1-2024, https://doi.org/10.5194/polf-92-1-2024, 2024
Short summary
Short summary
Drygalski führte in den Jahren 1891 und 1892/93 Forschungsarbeiten in Westgrönland durch, wobei zur Überwinterung eine Forschungsstation am Großen Karajak-Gletscher errichtetet wurde. An gleicher Stelle erfolgten durch die TU Dresden 2007 und 2019 geodätische Feldarbeiten. Im Beitrag werden das Areal der damaligen Station sowie die Forschungsarbeiten Drygalskis vorgestellt. Ein Vergleich mit heutigen Messungen zeigt, dass sich der Große Karajak-Gletscher in 120 Jahren kaum verändert hat.
Erik Loebel, Celia A. Baumhoer, Andreas Dietz, Mirko Scheinert, and Martin Horwath
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2023-535, https://doi.org/10.5194/essd-2023-535, 2024
Revised manuscript accepted for ESSD
Short summary
Short summary
Glacier calving front positions are important for understanding glacier dynamics and constrain ice modelling. We apply a deep learning framework on multispectral Landsat imagery to create a calving front record for 19 key outlet glaciers of the Antarctic Peninsula. The resulting data product includes 2064 calving front locations from 2013 to 2023 and achieves sub-seasonal temporal resolution.
Alexandra M. Zuhr, Erik Loebel, Marek Muchow, Donovan Dennis, Luisa von Albedyll, Frigga Kruse, Heidemarie Kassens, Johanna Grabow, Dieter Piepenburg, Sören Brandt, Rainer Lehmann, Marlene Jessen, Friederike Krüger, Monika Kallfelz, Andreas Preußer, Matthias Braun, Thorsten Seehaus, Frank Lisker, Daniela Röhnert, and Mirko Scheinert
Polarforschung, 91, 73–80, https://doi.org/10.5194/polf-91-73-2023, https://doi.org/10.5194/polf-91-73-2023, 2023
Short summary
Short summary
Polar research is an interdisciplinary and multi-faceted field of research. Its diversity ranges from history to geology and geophysics to social sciences and education. This article provides insights into the different areas of German polar research. This was made possible by a seminar series, POLARSTUNDE, established in the summer of 2020 and organized by the German Society of Polar Research and the German National Committee of the Association of Polar Early Career Scientists (APECS Germany).
Angelika Graiff, Matthias Braun, Amelie Driemel, Jörg Ebbing, Hans-Peter Grossart, Tilmann Harder, Joseph I. Hoffman, Boris Koch, Florian Leese, Judith Piontek, Mirko Scheinert, Petra Quillfeldt, Jonas Zimmermann, and Ulf Karsten
Polarforschung, 91, 45–57, https://doi.org/10.5194/polf-91-45-2023, https://doi.org/10.5194/polf-91-45-2023, 2023
Short summary
Short summary
There are many approaches to better understanding Antarctic processes that generate very large data sets (
Antarctic big data). For these large data sets there is a pressing need for improved data acquisition, curation, integration, service, and application to support fundamental scientific research, and this article describes and evaluates the current status of big data in various Antarctic scientific disciplines, identifies current gaps, and provides solutions to fill these gaps.
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.
Angelika Humbert, Veit Helm, Niklas Neckel, Ole Zeising, Martin Rückamp, Shfaqat Abbas Khan, Erik Loebel, Jörg Brauchle, Karsten Stebner, Dietmar Gross, Rabea Sondershaus, and Ralf Müller
The Cryosphere, 17, 2851–2870, https://doi.org/10.5194/tc-17-2851-2023, https://doi.org/10.5194/tc-17-2851-2023, 2023
Short summary
Short summary
The largest floating glacier mass in Greenland, the 79° N Glacier, is showing signs of instability. We investigate how crack formation at the glacier's calving front has changed over the last decades by using satellite imagery and airborne data. The calving front is about to lose contact to stabilizing ice islands. Simulations show that the glacier will accelerate as a result of this, leading to an increase in ice discharge of more than 5.1 % if its calving front retreats by 46 %.
Michael J. Bentley, James A. Smith, Stewart S. R. Jamieson, Margaret R. Lindeman, Brice R. Rea, Angelika Humbert, Timothy P. Lane, Christopher M. Darvill, Jeremy M. Lloyd, Fiamma Straneo, Veit Helm, and David H. Roberts
The Cryosphere, 17, 1821–1837, https://doi.org/10.5194/tc-17-1821-2023, https://doi.org/10.5194/tc-17-1821-2023, 2023
Short summary
Short summary
The Northeast Greenland Ice Stream is a major outlet of the Greenland Ice Sheet. Some of its outlet glaciers and ice shelves have been breaking up and retreating, with inflows of warm ocean water identified as the likely reason. Here we report direct measurements of warm ocean water in an unusual lake that is connected to the ocean beneath the ice shelf in front of the 79° N Glacier. This glacier has not yet shown much retreat, but the presence of warm water makes future retreat more likely.
Inès N. Otosaka, Andrew Shepherd, Erik R. Ivins, Nicole-Jeanne Schlegel, Charles Amory, Michiel R. van den Broeke, Martin Horwath, Ian Joughin, Michalea D. King, Gerhard Krinner, Sophie Nowicki, Anthony J. Payne, Eric Rignot, Ted Scambos, Karen M. Simon, Benjamin E. Smith, Louise S. Sørensen, Isabella Velicogna, Pippa L. Whitehouse, Geruo A, Cécile Agosta, Andreas P. Ahlstrøm, Alejandro Blazquez, William Colgan, Marcus E. Engdahl, Xavier Fettweis, Rene Forsberg, Hubert Gallée, Alex Gardner, Lin Gilbert, Noel Gourmelen, Andreas Groh, Brian C. Gunter, Christopher Harig, Veit Helm, Shfaqat Abbas Khan, Christoph Kittel, Hannes Konrad, Peter L. Langen, Benoit S. Lecavalier, Chia-Chun Liang, Bryant D. Loomis, Malcolm McMillan, Daniele Melini, Sebastian H. Mernild, Ruth Mottram, Jeremie Mouginot, Johan Nilsson, Brice Noël, Mark E. Pattle, William R. Peltier, Nadege Pie, Mònica Roca, Ingo Sasgen, Himanshu V. Save, Ki-Weon Seo, Bernd Scheuchl, Ernst J. O. Schrama, Ludwig Schröder, Sebastian B. Simonsen, Thomas Slater, Giorgio Spada, Tyler C. Sutterley, Bramha Dutt Vishwakarma, Jan Melchior van Wessem, David Wiese, Wouter van der Wal, and Bert Wouters
Earth Syst. Sci. Data, 15, 1597–1616, https://doi.org/10.5194/essd-15-1597-2023, https://doi.org/10.5194/essd-15-1597-2023, 2023
Short summary
Short summary
By measuring changes in the volume, gravitational attraction, and ice flow of Greenland and Antarctica from space, we can monitor their mass gain and loss over time. Here, we present a new record of the Earth’s polar ice sheet mass balance produced by aggregating 50 satellite-based estimates of ice sheet mass change. This new assessment shows that the ice sheets have lost (7.5 x 1012) t of ice between 1992 and 2020, contributing 21 mm to sea level rise.
Angelika Humbert, Julia Christmann, Hugh F. J. Corr, Veit Helm, Lea-Sophie Höyns, Coen Hofstede, Ralf Müller, Niklas Neckel, Keith W. Nicholls, Timm Schultz, Daniel Steinhage, Michael Wolovick, and Ole Zeising
The Cryosphere, 16, 4107–4139, https://doi.org/10.5194/tc-16-4107-2022, https://doi.org/10.5194/tc-16-4107-2022, 2022
Short summary
Short summary
Ice shelves are normally flat structures that fringe the Antarctic continent. At some locations they have channels incised into their underside. On Filchner Ice Shelf, such a channel is more than 50 km long and up to 330 m high. We conducted field measurements of basal melt rates and found a maximum of 2 m yr−1. Simulations represent the geometry evolution of the channel reasonably well. There is no reason to assume that this type of melt channel is destabilizing ice shelves.
Vasaw Tripathi, Andreas Groh, Martin Horwath, and Raaj Ramsankaran
Hydrol. Earth Syst. Sci., 26, 4515–4535, https://doi.org/10.5194/hess-26-4515-2022, https://doi.org/10.5194/hess-26-4515-2022, 2022
Short summary
Short summary
GRACE/GRACE-FO provided global observations of water storage change since 2002. Scaling is a common approach to compensate for the spatial filtering inherent to the results. However, for complex hydrological basins, the compatibility of scaling with the characteristics of regional hydrology has been rarely assessed. We assess traditional scaling approaches and a new scaling approach for the Indus Basin. Our results will help users with regional focus understand implications of scaling choices.
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.
Martin Horwath, Benjamin D. Gutknecht, Anny Cazenave, Hindumathi Kulaiappan Palanisamy, Florence Marti, Ben Marzeion, Frank Paul, Raymond Le Bris, Anna E. Hogg, Inès Otosaka, Andrew Shepherd, Petra Döll, Denise Cáceres, Hannes Müller Schmied, Johnny A. Johannessen, Jan Even Øie Nilsen, Roshin P. Raj, René Forsberg, Louise Sandberg Sørensen, Valentina R. Barletta, Sebastian B. Simonsen, Per Knudsen, Ole Baltazar Andersen, Heidi Ranndal, Stine K. Rose, Christopher J. Merchant, Claire R. Macintosh, Karina von Schuckmann, Kristin Novotny, Andreas Groh, Marco Restano, and Jérôme Benveniste
Earth Syst. Sci. Data, 14, 411–447, https://doi.org/10.5194/essd-14-411-2022, https://doi.org/10.5194/essd-14-411-2022, 2022
Short summary
Short summary
Global mean sea-level change observed from 1993 to 2016 (mean rate of 3.05 mm yr−1) matches the combined effect of changes in water density (thermal expansion) and ocean mass. Ocean-mass change has been assessed through the contributions from glaciers, ice sheets, and land water storage or directly from satellite data since 2003. Our budget assessments of linear trends and monthly anomalies utilise new datasets and uncertainty characterisations developed within ESA's Climate Change Initiative.
Lukas Müller, Martin Horwath, Mirko Scheinert, Christoph Mayer, Benjamin Ebermann, Dana Floricioiu, Lukas Krieger, Ralf Rosenau, and Saurabh Vijay
The Cryosphere, 15, 3355–3375, https://doi.org/10.5194/tc-15-3355-2021, https://doi.org/10.5194/tc-15-3355-2021, 2021
Short summary
Short summary
Harald Moltke Bræ, a marine-terminating glacier in north-western Greenland, undergoes remarkable surges of episodic character. Our data show that a recent surge from 2013 to 2019 was initiated at the glacier front and exhibits a pronounced seasonality with flow velocities varying by 1 order of magnitude, which has not been observed at Harald Moltke Bræ in this way before. These findings are crucial for understanding surge mechanisms at Harald Moltke Bræ and other marine-terminating glaciers.
Simon Deggim, Annette Eicker, Lennart Schawohl, Helena Gerdener, Kerstin Schulze, Olga Engels, Jürgen Kusche, Anita T. Saraswati, Tonie van Dam, Laura Ellenbeck, Denise Dettmering, Christian Schwatke, Stefan Mayr, Igor Klein, and Laurent Longuevergne
Earth Syst. Sci. Data, 13, 2227–2244, https://doi.org/10.5194/essd-13-2227-2021, https://doi.org/10.5194/essd-13-2227-2021, 2021
Short summary
Short summary
GRACE provides us with global changes of terrestrial water storage. However, the data have a low spatial resolution, and localized storage changes in lakes/reservoirs or mass change due to earthquakes causes leakage effects. The correction product RECOG RL01 presented in this paper accounts for these effects. Its application allows for improving calibration/assimilation of GRACE into hydrological models and better drought detection in earthquake-affected areas.
Mirko Scheinert, Christoph Mayer, Martin Horwath, Matthias Braun, Anja Wendt, and Daniel Steinhage
Polarforschung, 89, 57–64, https://doi.org/10.5194/polf-89-57-2021, https://doi.org/10.5194/polf-89-57-2021, 2021
Short summary
Short summary
Ice sheets, glaciers and further ice-covered areas with their changes as well as interactions with the solid Earth and the ocean are subject of intensive research, especially against the backdrop of global climate change. The resulting questions are of concern to scientists from various disciplines such as geodesy, glaciology, physical geography and geophysics. Thus, the working group "Polar Geodesy and Glaciology", founded in 2013, offers a forum for discussion and stimulating exchange.
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.
Evelyn Jäkel, Tim Carlsen, André Ehrlich, Manfred Wendisch, Michael Schäfer, Sophie Rosenburg, Konstantina Nakoudi, Marco Zanatta, Gerit Birnbaum, Veit Helm, Andreas Herber, Larysa Istomina, Linlu Mei, and Anika Rohde
The Cryosphere Discuss., https://doi.org/10.5194/tc-2021-14, https://doi.org/10.5194/tc-2021-14, 2021
Preprint withdrawn
Short summary
Short summary
Different approaches to retrieve the optical-equivalent snow grain size using satellite, airborne, and ground-based observations were evaluated and compared to modeled data. The study is focused on low Sun and partly rough surface conditions encountered North of Greenland in March/April 2018. We proposed an adjusted airborne retrieval method to reduce the retrieval uncertainty.
Tim Carlsen, Gerit Birnbaum, André Ehrlich, Veit Helm, Evelyn Jäkel, Michael Schäfer, and Manfred Wendisch
The Cryosphere, 14, 3959–3978, https://doi.org/10.5194/tc-14-3959-2020, https://doi.org/10.5194/tc-14-3959-2020, 2020
Short summary
Short summary
The angular reflection of solar radiation by snow surfaces is particularly anisotropic and highly variable. We measured the angular reflection from an aircraft using a digital camera in Antarctica in 2013/14 and studied its variability: the anisotropy increases with a lower Sun but decreases for rougher surfaces and larger snow grains. The applied methodology allows for a direct comparison with satellite observations, which generally underestimated the anisotropy measured within this study.
L. Drees, J. Kusche, and R. Roscher
ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., V-2-2020, 813–820, https://doi.org/10.5194/isprs-annals-V-2-2020-813-2020, https://doi.org/10.5194/isprs-annals-V-2-2020-813-2020, 2020
Marco Meloni, Jerome Bouffard, Tommaso Parrinello, Geoffrey Dawson, Florent Garnier, Veit Helm, Alessandro Di Bella, Stefan Hendricks, Robert Ricker, Erica Webb, Ben Wright, Karina Nielsen, Sanggyun Lee, Marcello Passaro, Michele Scagliola, Sebastian Bjerregaard Simonsen, Louise Sandberg Sørensen, David Brockley, Steven Baker, Sara Fleury, Jonathan Bamber, Luca Maestri, Henriette Skourup, René Forsberg, and Loretta Mizzi
The Cryosphere, 14, 1889–1907, https://doi.org/10.5194/tc-14-1889-2020, https://doi.org/10.5194/tc-14-1889-2020, 2020
Short summary
Short summary
This manuscript aims to describe the evolutions which have been implemented in the new CryoSat Ice processing chain Baseline-D and the validation activities carried out in different domains such as sea ice, land ice and hydrology.
This new CryoSat processing Baseline-D will maximise the uptake and use of CryoSat data by scientific users since it offers improved capability for monitoring the complex and multiscale changes over the cryosphere.
Isabel Meza, Stefan Siebert, Petra Döll, Jürgen Kusche, Claudia Herbert, Ehsan Eyshi Rezaei, Hamideh Nouri, Helena Gerdener, Eklavyya Popat, Janna Frischen, Gustavo Naumann, Jürgen V. Vogt, Yvonne Walz, Zita Sebesvari, and Michael Hagenlocher
Nat. Hazards Earth Syst. Sci., 20, 695–712, https://doi.org/10.5194/nhess-20-695-2020, https://doi.org/10.5194/nhess-20-695-2020, 2020
Short summary
Short summary
The paper presents, for the first time, a global-scale drought risk assessment for both irrigated and rainfed agricultural systems while considering drought hazard indicators, exposure and expert-weighted vulnerability indicators. We identify global patterns of drought risk and, by disaggregating risk into its underlying components and factors, provide entry points for risk reduction.
Matthias O. Willen, Martin Horwath, Ludwig Schröder, Andreas Groh, Stefan R. M. Ligtenberg, Peter Kuipers Munneke, and Michiel R. van den Broeke
The Cryosphere, 14, 349–366, https://doi.org/10.5194/tc-14-349-2020, https://doi.org/10.5194/tc-14-349-2020, 2020
Helena Gerdener, Olga Engels, and Jürgen Kusche
Hydrol. Earth Syst. Sci., 24, 227–248, https://doi.org/10.5194/hess-24-227-2020, https://doi.org/10.5194/hess-24-227-2020, 2020
Short summary
Short summary
GRACE-derived drought indicators enable us to detect hydrological droughts based on changes observed in all storages. By performing synthetic experiments, we find that droughts identified by existing and modified indicators are biased by trends and GRACE-based spatial noise. A modified version of the Zhao et al. (2017) indicator is found to be particularly robust against spatial noise and is therefore applied to real GRACE data over South Africa.
Stefan Schröder, Anne Springer, Jürgen Kusche, Bernd Uebbing, Luciana Fenoglio-Marc, Bernd Diekkrüger, and Thomas Poméon
Hydrol. Earth Syst. Sci., 23, 4113–4128, https://doi.org/10.5194/hess-23-4113-2019, https://doi.org/10.5194/hess-23-4113-2019, 2019
Short summary
Short summary
We propose deriving altimetric rating curves by
bridginggaps between time series from gauge and altimeter measurements using hydrological model simulations. We investigate several stations at the Niger River, which is a challenging region. We show that altimetry reproduces discharge well and enables continuing the gauge time series, albeit at a lower temporal resolution.
Ludwig Schröder, Martin Horwath, Reinhard Dietrich, Veit Helm, Michiel R. van den Broeke, and Stefan R. M. Ligtenberg
The Cryosphere, 13, 427–449, https://doi.org/10.5194/tc-13-427-2019, https://doi.org/10.5194/tc-13-427-2019, 2019
Short summary
Short summary
We developed an approach to combine measurements of seven satellite altimetry missions over the Antarctic Ice Sheet. Our resulting monthly grids of elevation changes between 1978 and 2017 provide unprecedented details of the long-term and interannual variation. Derived mass changes agree well with contemporaneous data of surface mass balance and satellite gravimetry and show which regions were responsible for the significant accelerations of mass loss in recent years.
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.
Kristin Vielberg, Ehsan Forootan, Christina Lück, Anno Löcher, Jürgen Kusche, and Klaus Börger
Ann. Geophys., 36, 761–779, https://doi.org/10.5194/angeo-36-761-2018, https://doi.org/10.5194/angeo-36-761-2018, 2018
Short summary
Short summary
To predict the satellite's motion or its re-entry, the density surrounding the satellite needs to be known as precisely as possible. Usually empirical models are used to estimate the neutral density of the thermosphere, which is the region of the neutrally charged atmosphere. Here, based on calibrated accelerations measured by instruments on board satellites, we compute daily global maps to correct modeled densities. During times of high solar activity, corrections of up to 28 % are necessary.
Christina Lück, Jürgen Kusche, Roelof Rietbroek, and Anno Löcher
Solid Earth, 9, 323–339, https://doi.org/10.5194/se-9-323-2018, https://doi.org/10.5194/se-9-323-2018, 2018
Short summary
Short summary
Since 2002, the GRACE mission provides estimates of the Earth's time-variable gravity field, from which one can derive ocean mass variability. Now that the GRACE mission has come to an end, it is especially important to find alternative ways for deriving ocean mass changes. For the first time, we use kinematic orbits of Swarm for computing ocean mass time series. We compute monthly solutions, but also show an alternative way of directly estimating time-variable spherical harmonic coefficients.
Ingo Sasgen, Alba Martín-Español, Alexander Horvath, Volker Klemann, Elizabeth J. Petrie, Bert Wouters, Martin Horwath, Roland Pail, Jonathan L. Bamber, Peter J. Clarke, Hannes Konrad, Terry Wilson, and Mark R. Drinkwater
Earth Syst. Sci. Data, 10, 493–523, https://doi.org/10.5194/essd-10-493-2018, https://doi.org/10.5194/essd-10-493-2018, 2018
Short summary
Short summary
We present a collection of data sets, consisting of surface-elevation rates for Antarctic ice sheet from a combination of Envisat and ICESat, bedrock uplift rates for 118 GPS sites in Antarctica, and optimally filtered GRACE gravity field rates. We provide viscoelastic response functions to a disc load forcing for Earth structures present in East and West Antarctica. This data collection enables a joint inversion for present-day ice-mass changes and glacial isostatic adjustment in Antarctica.
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.
Ludwig Schröder, Andreas Richter, Denis V. Fedorov, Lutz Eberlein, Evgeny V. Brovkov, Sergey V. Popov, Christoph Knöfel, Martin Horwath, Reinhard Dietrich, Alexey Y. Matveev, Mirko Scheinert, and Valery V. Lukin
The Cryosphere, 11, 1111–1130, https://doi.org/10.5194/tc-11-1111-2017, https://doi.org/10.5194/tc-11-1111-2017, 2017
Short summary
Short summary
The paper describes the processing of kinematic GNSS data observed over nine seasons in East Antarctica. The obtained surface elevation profiles are used to validate several data sets of satellite altimetry. Thus, we find a clear recommendation that processing versions provide the highest accuracy and precision. The profiles are used to derive a new set of ICESat laser campaign biases and finally, to evaluate several DEMs.
Thomas B. Overly, Robert L. Hawley, Veit Helm, Elizabeth M. Morris, and Rohan N. Chaudhary
The Cryosphere, 10, 1679–1694, https://doi.org/10.5194/tc-10-1679-2016, https://doi.org/10.5194/tc-10-1679-2016, 2016
Short summary
Short summary
We demonstrate that snow accumulation rates across the Greenland Ice Sheet, determined from RADAR layers and modeled snow density profiles, are identical to ground-based measurements of snow accumulation. Three regional climate models underestimate snow accumulation compared to RADAR layer estimates. Using RADAR increases spatial coverage and improves accuracy of snow accumulation estimates. Incorporating our results into climate models may reduce uncertainty of sea-level rise estimates.
Sandra Schwegmann, Eero Rinne, Robert Ricker, Stefan Hendricks, and Veit Helm
The Cryosphere, 10, 1415–1425, https://doi.org/10.5194/tc-10-1415-2016, https://doi.org/10.5194/tc-10-1415-2016, 2016
Short summary
Short summary
Our study aimed to investigate whether CS-2 and Envisat radar freeboard can be merged without intermission biases in order to obtain a 20-year data set. The comparison revealed a reasonable regional agreement between radar freeboards derived from both sensors. Differences are mostly below 0.1 m for modal freeboard and even less for mean freeboard over winter months (May–October). The highest differences occur in regions with multi-year sea ice and along the coasts.
Alexey Ekaykin, Lutz Eberlein, Vladimir Lipenkov, Sergey Popov, Mirko Scheinert, Ludwig Schröder, and Alexey Turkeev
The Cryosphere, 10, 1217–1227, https://doi.org/10.5194/tc-10-1217-2016, https://doi.org/10.5194/tc-10-1217-2016, 2016
S. Goeller, V. Helm, M. Thoma, and K. Grosfeld
The Cryosphere Discuss., https://doi.org/10.5194/tcd-9-3995-2015, https://doi.org/10.5194/tcd-9-3995-2015, 2015
Revised manuscript has not been submitted
Short summary
Short summary
The Ross Ice Streams in West Antarctica showed a high variability in the past. We model basal water pathways and catchment areas for present and future ice sheet geometries (gained by applying satellite-derived elevation change rates) in this sector. Thus, we can explain the current ice stream configuration and estimate implications for the next two centuries, where we find that a major basal hydraulic tributary of the Kamb and Whillans IS could be redirected underneath the Bindschadler IS.
R. Ricker, S. Hendricks, V. Helm, H. Skourup, and M. Davidson
The Cryosphere, 8, 1607–1622, https://doi.org/10.5194/tc-8-1607-2014, https://doi.org/10.5194/tc-8-1607-2014, 2014
V. Helm, A. Humbert, and H. Miller
The Cryosphere, 8, 1539–1559, https://doi.org/10.5194/tc-8-1539-2014, https://doi.org/10.5194/tc-8-1539-2014, 2014
L. Gray, D. Burgess, L. Copland, R. Cullen, N. Galin, R. Hawley, and V. Helm
The Cryosphere, 7, 1857–1867, https://doi.org/10.5194/tc-7-1857-2013, https://doi.org/10.5194/tc-7-1857-2013, 2013
M. Zygmuntowska, K. Khvorostovsky, V. Helm, and S. Sandven
The Cryosphere, 7, 1315–1324, https://doi.org/10.5194/tc-7-1315-2013, https://doi.org/10.5194/tc-7-1315-2013, 2013
Related subject area
Discipline: Ice sheets | Subject: Mass Balance Obs
Mapping geodetically inferred Antarctic ice surface height changes into thickness changes: a sensitivity study
On the importance of the humidity flux for the surface mass balance in the accumulation zone of the Greenland Ice Sheet
Combined GNSS reflectometry–refractometry for automated and continuous in situ surface mass balance estimation on an Antarctic ice shelf
Evaluating Greenland surface-mass-balance and firn-densification data using ICESat-2 altimetry
The regional-scale surface mass balance of Pine Island Glacier, West Antarctica, over the period 2005–2014, derived from airborne radar soundings and neutron probe measurements
Sensitivity of inverse glacial isostatic adjustment estimates over Antarctica
Recent precipitation decrease across the western Greenland ice sheet percolation zone
How does the ice sheet surface mass balance relate to snowfall? Insights from a ground-based precipitation radar in East Antarctica
Spatial and temporal distributions of surface mass balance between Concordia and Vostok stations, Antarctica, from combined radar and ice core data: first results and detailed error analysis
Natasha Valencic, Linda Pan, Konstantin Latychev, Natalya Gomez, Evelyn Powell, and Jerry X. Mitrovica
The Cryosphere, 18, 2969–2978, https://doi.org/10.5194/tc-18-2969-2024, https://doi.org/10.5194/tc-18-2969-2024, 2024
Short summary
Short summary
We quantify the effect of ongoing Antarctic bedrock uplift due to Ice Age or modern ice mass changes on estimates of ice thickness changes obtained from satellite-based ice height measurements. We find that variations in the Ice Age signal introduce an uncertainty in estimates of total Antarctic ice change of up to ~10%. Moreover, the usual assumption that the mapping between modern ice height and thickness changes is uniform systematically underestimates net Antarctic ice volume changes.
Laura J. Dietrich, Hans Christian Steen-Larsen, Sonja Wahl, Anne-Katrine Faber, and Xavier Fettweis
The Cryosphere, 18, 289–305, https://doi.org/10.5194/tc-18-289-2024, https://doi.org/10.5194/tc-18-289-2024, 2024
Short summary
Short summary
The contribution of the humidity flux to the surface mass balance in the accumulation zone of the Greenland Ice Sheet is uncertain. Here, we evaluate the regional climate model MAR using a multi-annual dataset of eddy covariance measurements and bulk estimates of the humidity flux. The humidity flux largely contributes to the summer surface mass balance (SMB) in the accumulation zone, indicating its potential importance for the annual SMB in a warming climate.
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.
Benjamin E. Smith, Brooke Medley, Xavier Fettweis, Tyler Sutterley, Patrick Alexander, David Porter, and Marco Tedesco
The Cryosphere, 17, 789–808, https://doi.org/10.5194/tc-17-789-2023, https://doi.org/10.5194/tc-17-789-2023, 2023
Short summary
Short summary
We use repeated satellite measurements of the height of the Greenland ice sheet to learn about how three computational models of snowfall, melt, and snow compaction represent actual changes in the ice sheet. We find that the models do a good job of estimating how the parts of the ice sheet near the coast have changed but that two of the models have trouble representing surface melt for the highest part of the ice sheet. This work provides suggestions for how to better model snowmelt.
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.
Matthias O. Willen, Martin Horwath, Ludwig Schröder, Andreas Groh, Stefan R. M. Ligtenberg, Peter Kuipers Munneke, and Michiel R. van den Broeke
The Cryosphere, 14, 349–366, https://doi.org/10.5194/tc-14-349-2020, https://doi.org/10.5194/tc-14-349-2020, 2020
Gabriel Lewis, Erich Osterberg, Robert Hawley, Hans Peter Marshall, Tate Meehan, Karina Graeter, Forrest McCarthy, Thomas Overly, Zayta Thundercloud, and David Ferris
The Cryosphere, 13, 2797–2815, https://doi.org/10.5194/tc-13-2797-2019, https://doi.org/10.5194/tc-13-2797-2019, 2019
Short summary
Short summary
We present accumulation records from sixteen 22–32 m long firn cores and 4436 km of ground-penetrating radar, covering the past 20–60 years of accumulation, collected across the western Greenland Ice Sheet percolation zone. Trends from both radar and firn cores, as well as commonly used regional climate models, show decreasing accumulation over the 1996–2016 period.
Niels Souverijns, Alexandra Gossart, Irina V. Gorodetskaya, Stef Lhermitte, Alexander Mangold, Quentin Laffineur, Andy Delcloo, and Nicole P. M. van Lipzig
The Cryosphere, 12, 1987–2003, https://doi.org/10.5194/tc-12-1987-2018, https://doi.org/10.5194/tc-12-1987-2018, 2018
Short summary
Short summary
This work is the first to gain insight into the local surface mass balance over Antarctica using accurate long-term snowfall observations. A non-linear relationship between accumulation and snowfall is discovered, indicating that total surface mass balance measurements are not a good proxy for snowfall over Antarctica. Furthermore, the meteorological drivers causing changes in the local SMB are identified.
Emmanuel Le Meur, Olivier Magand, Laurent Arnaud, Michel Fily, Massimo Frezzotti, Marie Cavitte, Robert Mulvaney, and Stefano Urbini
The Cryosphere, 12, 1831–1850, https://doi.org/10.5194/tc-12-1831-2018, https://doi.org/10.5194/tc-12-1831-2018, 2018
Short summary
Short summary
This paper presents surface mass balance measurements from both GPR and ice core data collected during a traverse in a so-far-unexplored area between the DC and Vostok stations. Results presented here will contribute to a better knowledge of the global mass balance of the Antarctic ice sheet and thus help in constraining its contribution to sea level rise. Another novelty of the paper resides in the comprehensive error budget proposed for the method used for inferring accumulation rates.
Cited articles
Barletta, V., Bevis, M., Smith, B., Wilson, T., Brown, A., Bordoni, A., Willis, M., Khan, S., Rovira-Navarro, M., Dalziel, I., Smalley Jr., R., Kendrick, E., Konfal, S., Caccamise II, D., Aster, R., Nyblade, A., and Wiens, D.: Observed rapid bedrock uplift in Amundsen Sea Embayment promotes ice-sheet stability, Science, 360, 1335–1339, https://doi.org/10.1126/science.aao1447, 2018. a
Blewitt, G. and Clarke, P.: Inversion of Earth's changing shape to weigh sea level in static equilibrium with surface mass redistribution, J. Geophys. Res., 108, 2311, https://doi.org/10.1029/2002JB002290, 2003. a
Blewitt, G., Kreemer, C., Hammond, W., and Gazeaux, J.: MIDAS robust trend estimator for accurate GPS station velocities without step detection: MIDAS Trend Estimator for GPS Velocities, J. Geophys. Res.-Sol. Ea., 121, 2054–2068, https://doi.org/10.1002/2015JB012552, 2016. a
Buchta, E., Scheinert, M., King, M., Wilson, T., Kendrick, E., Koulali, A., Clarke, P., and Knöfel, C.: GIANT-REGAIN: A comprehensive analysis of geodetic GNSS recordings in Antarctica for geodetic and geodynamic applications, 347 pp., SCAR, ISBN 978-0-948277-64-1, https://scar.org/~documents/conferences/scar-open-science-conferences/abstracts/scar-open-science-conference-2022-abstracts?layout=default (last access: 12 April 2023), 2022. a
Caron, L. and Ivins, E.: A baseline Antarctic GIA correction for space gravimetry, Earth Planet. Sc. Lett., 531, 115957, https://doi.org/10.1016/j.epsl.2019.115957, 2020. a
Chen, J., Cazenave, A., Dahle, C., Llovel, W., Panet, I., Pfeffer, J., and Moreira, L.: Applications and Challenges of GRACE and GRACE Follow-On Satellite Gravimetry, Surv. Geophys., 43, 305–345, https://doi.org/10.1007/s10712-021-09685-x, 2022. a
Clarke, P., Lavallée, D., Blewitt, G., van Dam, T., and Wahr, J.: Effect of gravitational consistency and mass conservation on seasonal surface mass loading models, Geophys. Res. Lett., 32, L08306, https://doi.org/10.1029/2005GL022441, 2005. a
Ditmar, P.: How to quantify the accuracy of mass anomaly time-series based on GRACE data in the absence of knowledge about true signal?, J. Geod., 96, 54, https://doi.org/10.1007/s00190-022-01640-x, 2022. a, b
Döhne, T., Horwath, M., Groh, A., and Buchta, E.: The sensitivity kernel perspective on GRACE mass change estimates, J. Geod., 97, 11, https://doi.org/10.1007/s00190-022-01697-8, 2023. a
Dziewonski, A. and Anderson, D.: Preliminary reference Earth model, Phys. Earth Plan. Int., 25, 297–356, https://doi.org/10.1016/0031-9201(81)90046-7, 1981. a
European Space Agency: L1b NOP-IOP-GOP SAR, Version Baseline C., ESA [data set], https://earth.esa.int/eogateway/catalog/cryosat-products, last access: 12 October 2022. a
Farrell, W.: Deformation of the Earth by Surface Loads, Rev. Geophys. Space Phys., 10, 761–797, https://doi.org/10.1029/RG010i003p00761, 1972. a
Farrell, W. and Clark, J.: On Postglacial Sea Level, Geophys. J. R. Astr. Soc., 46, 647–667, https://doi.org/10.1111/j.1365-246X.1976.tb01252.x, 1976. a
Fox-Kemper, B., Hewitt, H., Xiao, C., Aðalgeirsdóttir, G., Drijfhout, S., Edwards, T., Golledge, N., Hemer, M., Kopp, R., Krinner, G., Mix, A., Notz, D., Nowicki, S., Nurhati, I., Ruiz, L., Sallée, J.-B., Slangen, A., and Yu, Y.: Chapter 9: Ocean, Cryosphere and Sea Level Change, Cambridge University Press, 1211–1362, https://doi.org/10.1017/9781009157896.011, 2021a. a
Fox-Kemper, B., Hewitt, H., Xiao, C., Aðalgeirsdóttir, G., Drijfhout, S., Edwards, T., Golledge, N., Hemer, M., Kopp, R., Krinner, G., Mix, A., Notz, D., Nowicki, S., Nurhati, I., Ruiz, L., Sallée, J.-B., Slangen, A., and Yu, Y.: Ocean, Cryosphere and Sea Level Change Supplementary Material, https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter09_SM.pdf (last access: 29 July 2022), 2021b. a, b
Groh, A. and Horwath, M.: Antarctic Ice Mass Change Products from GRACE/GRACE-FO Using Tailored Sensitivity Kernels, MDPI Remote Sens., 13, 1736, https://doi.org/10.3390/rs13091736, 2021. a, b
Gunter, B. C., Didova, O., Riva, R. E. M., Ligtenberg, S. R. M., Lenaerts, J. T. M., King, M. A., van den Broeke, M. R., and Urban, T.: Empirical estimation of present-day Antarctic glacial isostatic adjustment and ice mass change, The Cryosphere, 8, 743–760, https://doi.org/10.5194/tc-8-743-2014, 2014. a, b, c, d, e, f, g
Hanna, E., Pattyn, F., Navarro, F., Favier, V., Goelzer, H., van den Broeke, M., Vizcaino, M., Whitehouse, P., Ritz, C., Bulthuis, K., and Smith, B.: Mass balance of the ice sheets and glaciers – Progress since AR5 and challenges, Earth-Sci. Rev., 201, 102976, https://doi.org/10.1016/j.earscirev.2019.102976, 2020. a
Hansen, P. C.: The L-Curve and its Use in the Numerical Treatment of Inverse Problems, in: Computational Inverse Problems in Electrocardiography, WIT Press, 119–142, ISBN 978-1-85312-614-7, https://www.witpress.com/books/978-1-85312-614-7 (last access: 23 November 2020), 2001. a
Helm, V., Humbert, A., and Miller, H.: Elevation and elevation change of Greenland and Antarctica derived from CryoSat-2, The Cryosphere, 8, 1539–1559, https://doi.org/10.5194/tc-8-1539-2014, 2014. a, b, c, d
Helm, V., Dehghanpour, A., Hänsch, R., Loebel, E., Horwath, M., and Humbert, A.: AWI-ICENet1: A convolutional neural network retracker for ice altimetry, The Cryosphere Discuss. [preprint], https://doi.org/10.5194/tc-2023-80, in review, 2023. a
Ivins, E., van der Wal, W., Wiens, D., Lloyd, A., and Caron, L.: Antarctic upper mantle rheology, Geological Society, London, Memoirs, 56, M56–2020, https://doi.org/10.1144/M56-2020-19, 2021. a
Jiang, Y., Wu, X., van den Broeke, M., Kuipers Munneke, P., Simonsen, S., van der Wal, W., and Vermeersen, B.: Assessing Global Present-Day Surface Mass Transport and Glacial Isostatic Adjustment From Inversion of Geodetic Observations, J. Geophys. Res.-Sol. Ea., 126, e2020JB020713, https://doi.org/10.1029/2020JB020713, 2021. a, b, c
Kappelsberger, M. T., Horwath, M., Buchta, E., Willen, M. O., Schröder, L., Veldhuijsen, S. B. M., Kuipers Munneke, P., and van den Broeke, M. R.: How well can satellite altimetry and firn models resolve Antarctic firn thickness variations?, The Cryosphere Discuss. [preprint], https://doi.org/10.5194/tc-2023-140, in review, 2023. a
Kittel, C.: Kittel et al. (2021), The Cryosphere: MAR and ESMs data, Zenodo [data set], https://doi.org/10.5281/zenodo.4459259, 2021. a
Kittel, C., Amory, C., Agosta, C., Jourdain, N. C., Hofer, S., Delhasse, A., Doutreloup, S., Huot, P.-V., Lang, C., Fichefet, T., and Fettweis, X.: Diverging future surface mass balance between the Antarctic ice shelves and grounded ice sheet, The Cryosphere, 15, 1215–1236, https://doi.org/10.5194/tc-15-1215-2021, 2021. a, b, c
Koch, K.: Parameter Estimation and Hypothesis Testing in Linear Models, 2nd edn., Springer, Berlin, Heidelberg, ISBN 978-3-662-03976-2, https://doi.org/10.1007/978-3-662-03976-2, 1999. a
Kvas, A., Behzadpour, S., Ellmer, M., Klinger, B., Strasser, S., Zehentner, N., and Mayer-Gürr, T.: ITSG-Grace2018: Overview and Evaluation of a New GRACE-Only Gravity Field Time Series, J. Geophys. Res.-Sol. Ea., 124, 9332–9344, https://doi.org/10.1029/2019JB017415, 2019. a
Lenaerts, J., Medley, B., Broeke, M., and Wouters, B.: Observing and Modeling Ice Sheet Surface Mass Balance, Rev. Geophys., 57, 376–420, https://doi.org/10.1029/2018RG000622, 2019. a
Loomis, B., Rachlin, K., Wiese, D., Landerer, F., and Luthcke, S.: Replacing GRACE/GRACE-FO C30 with satellite laser ranging: Impacts on Antarctic Ice Sheet mass change, Geophys. Res. Lett., 47, e2020GL088306, https://doi.org/10.1029/2019GL085488, 2020. a
Martín-Español, A., Zammit-Mangion, A., Clarke, P., Flament, T., Helm, V., King, M. A., Luthcke, S. B., Petrie, E., Rémy, F., Schön, N., Wouters, B., and Bamber, J.: Spatial and temporal Antarctic Ice Sheet mass trends, glacio-isostatic adjustment and surface processes from a joint inversion of satellite altimeter, gravity and GPS data, J. Geophys. Res.-Earth, 121, 182–200, https://doi.org/10.1002/2015JF003550, 2016. a, b, c
Mayer-Gürr, T., Behzadpur, S., Ellmer, M., Kvas, A., Klinger, B., Strasser, S., and Zehentner, N.: ITSG-Grace2018 – Monthly, Daily and Static Gravity Field Solutions from GRACE, GFZ Data Services [data set], https://doi.org/10.5880/ICGEM.2018.003, 2018. a, b, c, d
Mottram, R., Hansen, N., Kittel, C., van Wessem, J. M., Agosta, C., Amory, C., Boberg, F., van de Berg, W. J., Fettweis, X., Gossart, A., van Lipzig, N. P. M., van Meijgaard, E., Orr, A., Phillips, T., Webster, S., Simonsen, S. B., and Souverijns, N.: What is the surface mass balance of Antarctica? An intercomparison of regional climate model estimates, The Cryosphere, 15, 3751–3784, https://doi.org/10.5194/tc-15-3751-2021, 2021. a, b, c, d
Mouginot, J., Scheuchl, B., and Rignot, E.: MEaSUREs Antarctic Boundaries for IPY 2007–2009 from Satellite Radar, Version 2, NSIDC [data set], https://doi.org/10.5067/AXE4121732AD, 2017. a
Nield, G., Barletta, V., Bordoni, A., King, M., Whitehouse, P., Clarke, P., Domack, E., Scambos, T., and Berthier, E.: Rapid bedrock uplift in the Antarctic Peninsula explained by viscoelastic response to recent ice unloading, Earth Planet. Sc. Lett., 397, 32–41, https://doi.org/10.1016/j.epsl.2014.04.019, 2014. a, b
Otosaka, I., Horwath, M., Mottram, R., and Nowicki, S.: Mass Balances of the Antarctic and Greenland Ice Sheets Monitored from Space, Surv. Geophys., 44, 1615–1652, https://doi.org/10.1007/s10712-023-09795-8, 2023a. a
Otosaka, I. N., Shepherd, A., Ivins, E. R., Schlegel, N.-J., Amory, C., van den Broeke, M. R., Horwath, M., Joughin, I., King, M. D., Krinner, G., Nowicki, S., Payne, A. J., Rignot, E., Scambos, T., Simon, K. M., Smith, B. E., Sørensen, L. S., Velicogna, I., Whitehouse, P. L., A, G., Agosta, C., Ahlstrøm, A. P., Blazquez, A., Colgan, W., Engdahl, M. E., Fettweis, X., Forsberg, R., Gallée, H., Gardner, A., Gilbert, L., Gourmelen, N., Groh, A., Gunter, B. C., Harig, C., Helm, V., Khan, S. A., Kittel, C., Konrad, H., Langen, P. L., Lecavalier, B. S., Liang, C.-C., Loomis, B. D., McMillan, M., Melini, D., Mernild, S. H., Mottram, R., Mouginot, J., Nilsson, J., Noël, B., Pattle, M. E., Peltier, W. R., Pie, N., Roca, M., Sasgen, I., Save, H. V., Seo, K.-W., Scheuchl, B., Schrama, E. J. O., Schröder, L., Simonsen, S. B., Slater, T., Spada, G., Sutterley, T. C., Vishwakarma, B. D., van Wessem, J. M., Wiese, D., van der Wal, W., and Wouters, B.: Mass balance of the Greenland and Antarctic ice sheets from 1992 to 2020, Earth Syst. Sci. Data, 15, 1597–1616, https://doi.org/10.5194/essd-15-1597-2023, 2023b. a, b, c, d, e
Pie, N., Bettadpur, S., Tamisiea, M., Krichman, B., Save, H., Poole, S., Nagel, P., Kang, Z., Jacob, G., Ellmer, M., Fahnestock, E., Landerer, F., McCullough, C., Yuan, D.-N., and Wiese, D.: Time Variable Earth Gravity Field Models From the First Spaceborne Laser Ranging Interferometer, J. Geophys. Res.-Sol. Ea., 126, e2021JB022392, https://doi.org/10.1029/2021JB022392, 2021. a, b, c
Pollack, H.: Spherical harmonic representation of the gravitational potential of a point mass, a spherical cap, and a spherical rectangle, J. Geophys. Res., 78, 1760–1768, https://doi.org/10.1029/JB078i011p01760, 1973. a
Rignot, E., Mouginot, J., Scheuchl, B., van den Broeke, M., Van Wessem, J., and Morlighem, M.: Four decades of Antarctic Ice Sheet mass balance from 1979–2017, P. Natl. Acad. Sci. USA, 116, 1095–1103, https://doi.org/10.1073/pnas.1812883116, 2019. a
Riva, R., Gunter, B., Urban, T., Vermeersen, B., Lindenbergh, R., Helsen, M., Bamber, J., van de Wal, R., van den Broeke, M., and Schutz, B.: Glacial Isostatic Adjustment over Antarctica from combined ICESat and GRACE satellite data, Earth Planet. Sci. Lett., 288, 516–523, https://doi.org/10.1016/j.epsl.2009.10.013, 2009. a, b, c, d, e
Samrat, N., King, M., Watson, C., Hay, A., Barletta, V., and Bordoni, A.: Upper Mantle Viscosity Underneath Northern Marguerite Bay, Antarctic Peninsula Constrained by Bedrock Uplift and Ice Mass Variability, Geophys. Res. Lett., 48, e2021GL097065, https://doi.org/10.1029/2021GL097065, 2021. a, b
Sasgen, I., Martín-Español, A., Horvath, A., Klemann, V., Petrie, E., Wouters, B., Horwath, M., Pail, R., Bamber, J., Clarke, P., Konrad, H., and Drinkwater, M.: Joint inversion estimate of regional glacial isostatic adjustment in Antarctica considering a lateral varying Earth structure (ESA STSE Project REGINA), Geophys. J. Int., 211, 1534–1553, https://doi.org/10.1093/gji/ggx368, 2017. a, b, c, d
Schröder, L., Horwath, M., Dietrich, R., Helm, V., van den Broeke, M. R., and Ligtenberg, S. R. M.: Four decades of Antarctic surface elevation changes from multi-mission satellite altimetry, The Cryosphere, 13, 427–449, https://doi.org/10.5194/tc-13-427-2019, 2019. a, b
Shepherd, A., Ivins, E., Rignot, E., Smith, B., van den Broeke, M., Velicogna, I., Whitehouse, P., Briggs, K., Joughin, I., Krinner, G., Nowicki, S., Payne, T., Scambos, T., Schlegel, N., A, G., Agosta, C., Ahlstrøm, A., Babonis, G., Barletta, V., Blazquez, A., Bonin, J., Csatho, B., Cullather, R., Felikson, D., Fettweis, X., Forsberg, R., Gallee, H., Gardner, A., Gilbert, L., Groh, A., Gunter, B., Hanna, E., Harig, C., Helm, V., Horvath, A., Horwath, M., Khan, S., Kjeldsen, K., Konrad, H., Langen, P., Lecavalier, B., Loomis, B., Luthcke, S., McMillan, M., Melini, D., Mernild, S., Mohajerani, Y., Moore, P., Mouginot, J., Moyano, G., Muir, A., Nagler, T., Nield, G., Nilsson, J., Noel, B., Otosaka, I., Pattle, M., Peltier, W., Pie, N., Rietbroek, R., Rott, H., Sandberg-Sørensen, L., Sasgen, I., Save, H., Scheuchl, B., Schrama, E., Schröder, L., Seo, K.-W., Simonsen, S., Slater, T., Spada, G., Sutterley, T., Talpe, M., Tarasov, L., van de Berg, W., van der Wal, W., van Wessem, J., Vishwakarma, B., Wiese, D., and Wouters, B.: Mass balance of the Antarctic Ice Sheet from 1992 to 2017, Nature, 558, 219–222, https://doi.org/10.1038/s41586-018-0179-y, 2018. a
Spada, G. and Melini, D.: SELEN4 (SELEN version 4.0): a Fortran program for solving the gravitationally and topographically self-consistent sea-level equation in glacial isostatic adjustment modeling, Geosci. Model Dev., 12, 5055–5075, https://doi.org/10.5194/gmd-12-5055-2019, 2019. a, b, c
Sun, Y., Riva, R., and Ditmar, P.: Optimizing estimates of annual variations and trends in geocenter motion and J2 from a combination of GRACE data and geophysical models, J. Geophys. Res.-Sol. Ea., 121, 8352–8370, https://doi.org/10.1002/2016JB013073, 2016. a
Swenson, S. and Wahr, J.: Post-processing removal of correlated errors in GRACE data, Geophys. Res. Lett., 33, L08402, https://doi.org/10.1029/2005GL025285, 2006. a
Thomas, I., King, M., Bentley, M., Whitehouse, P., Penna, N., Williams, S., Riva, R., Lavallee, D., Clarke, P., King, E., Hindmarsh, R., and Koivula, H.: Widespread low rates of Antarctic glacial isostatic adjustment revealed by GPS observations, Geophys. Res. Lett., 38, L22302, https://doi.org/10.1029/2011GL049277, 2011. a
Tikhonov, A. N., Goncharsky, A. V., Stepanov, V. V., and Yagola, A. G.: Numerical Methods for the Solution of Ill-Posed Problems, Kluwer Academic Publishers, ISBN 978-90-481-4583-6, https://doi.org/10.1007/978-94-015-8480-7, 1995. a
Uebbing, B., Kusche, J., Rietbroek, R., and Landerer, F.: Processing choices affect ocean mass estimates from GRACE, J. Geophys. Res.-Oceans, 124, https://doi.org/10.1029/2018JC014341, 2019. a, b
van Wessem, J. M., van de Berg, W. J., Noël, B. P. Y., van Meijgaard, E., Amory, C., Birnbaum, G., Jakobs, C. L., Krüger, K., Lenaerts, J. T. M., Lhermitte, S., Ligtenberg, S. R. M., Medley, B., Reijmer, C. H., van Tricht, K., Trusel, L. D., van Ulft, L. H., Wouters, B., Wuite, J., and van den Broeke, M. R.: Modelling the climate and surface mass balance of polar ice sheets using RACMO2 – Part 2: Antarctica (1979–2016), The Cryosphere, 12, 1479–1498, https://doi.org/10.5194/tc-12-1479-2018, 2018. a, b, c, d, e
Vishwakarma, B., Horwath, M., Groh, A., and Bamber, J.: Accounting for GIA signal in GRACE products, Geophys. J. Int., 228, 2056–2060, https://doi.org/10.1093/gji/ggab464, 2022. a
Wahr, J., Molenaar, M., and Bryan, F.: Time variability of the Earth's gravity field: Hydrological and oceanic effects and their possible detection using GRACE, J. Geophys. Res., 103, 30205–30229, https://doi.org/10.1029/98JB02844, 1998. a, b
Wahr, J., Wingham, D., and Bentley, C.: A method of combining ICESat and GRACE satellite data to constrain Antarctic mass balance, J. Geophys. Res., 105, 16279–16294, https://doi.org/10.1029/2000JB900113, 2000. a
Willen, M. O., Horwath, M., Schröder, L., Groh, A., Ligtenberg, S. R. M., Kuipers Munneke, P., and van den Broeke, M. R.: Sensitivity of inverse glacial isostatic adjustment estimates over Antarctica, The Cryosphere, 14, 349–366, https://doi.org/10.5194/tc-14-349-2020, 2020. a, b, c
Willen, M., Horwath, M., Groh, A., Helm, V., Uebbing, B., and Kusche, J.: Feasibility of a global inversion for spatially resolved glacial isostatic adjustment and ice sheet mass changes proven in simulation experiments, J. Geod., 96, 75, https://doi.org/10.1007/s00190-022-01651-8, 2022. a, b, c, d, e, f, g, h, i, j, k, l
Zhang, B., Wang, Z., Li, F., An, J., Yang, Y., and Liu, J.: Estimation of present-day glacial isostatic adjustment, ice mass change and elastic vertical crustal deformation over the Antarctic ice sheet, J. Glac., 63, 703–715, https://doi.org/10.1017/jog.2017.37, 2017. a
Zwally, H. J., Giovinetto, M. B., Beckley, M. A., and Saba, J. L.: Antarctic and Greenland Drainage Systems, GSFC Cryospheric Sciences Laboratory, https://earth.gsfc.nasa.gov/cryo/data/polar-altimetry/antarctic-and-greenland-drainage-systems (last access: 28 October 2021), 2012. a
Zwally, H., Robbins, J., Luthcke, S., Loomis, B., and Rémy, F.: Mass balance of the Antarctic ice sheet 1992–2016: reconciling results from GRACE gravimetry with ICESat, ERS1/2 and Envisat altimetry, J. Glac., 67, 533–559, https://doi.org/10.1017/jog.2021.8, 2021. a
Short summary
Shrinkage of the Antarctic ice sheet (AIS) leads to sea level rise. Satellite gravimetry measures AIS mass changes. We apply a new method that overcomes two limitations: low spatial resolution and large uncertainties due to the Earth's interior mass changes. To do so, we additionally include data from satellite altimetry and climate and firn modelling, which are evaluated in a globally consistent way with thoroughly characterized errors. The results are in better agreement with independent data.
Shrinkage of the Antarctic ice sheet (AIS) leads to sea level rise. Satellite gravimetry...
