Articles | Volume 14, issue 8
Research article 27 Aug 2020
Research article | 27 Aug 2020
Quantifying spatiotemporal variability of glacier algal blooms and the impact on surface albedo in southwestern Greenland
Shujie Wang et al.
No articles found.
Christoph Kittel, Charles Amory, Stefan Hofer, Cécile Agosta, Nicolas C. Jourdain, Ella Gilbert, Louis Le Toumelin, Hubert Gallée, and Xavier Fettweis
The Cryosphere Discuss.,
Preprint under review for TCShort summary
Model projections with similar greenhouse gas scenarios suggest large differences in future surface melting. So far it remains unclear whether these differences are due to variations in warming rates in individual models, or whether local surface energy budget feedbacks could also play a notable role. We show that clouds containing a larger amount of liquid water lead to stronger melt, subsequently favouring the absorption of solar radiation due to the snow-melt-albedo feedback.
Ruth Mottram, Nicolaj Hansen, Christoph Kittel, J. Melchior van Wessem, Cécile Agosta, Charles Amory, Fredrik Boberg, Willem Jan van de Berg, Xavier Fettweis, Alexandra Gossart, Nicole P. M. van Lipzig, Erik van Meijgaard, Andrew Orr, Tony Phillips, Stuart Webster, Sebastian B. Simonsen, and Niels Souverijns
The Cryosphere, 15, 3751–3784,Short summary
We compare the calculated surface mass budget (SMB) of Antarctica in five different regional climate models. On average ~ 2000 Gt of snow accumulates annually, but different models vary by ~ 10 %, a difference equivalent to ± 0.5 mm of global sea level rise. All models reproduce observed weather, but there are large differences in regional patterns of snowfall, especially in areas with very few observations, giving greater uncertainty in Antarctic mass budget than previously identified.
Louis Le Toumelin, Charles Amory, Vincent Favier, Christoph Kittel, Stefan Hofer, Xavier Fettweis, Hubert Gallée, and Vinay Kayetha
The Cryosphere, 15, 3595–3614,Short summary
Snow is frequently eroded from the surface by the wind in Adelie Land (Antarctica) and suspended in the lower atmosphere. By performing model simulations, we show firstly that suspended snow layers interact with incoming radiation similarly to a near-surface cloud. Secondly, suspended snow modifies the atmosphere's thermodynamic structure and energy exchanges with the surface. Our results suggest snow transport by the wind should be taken into account in future model studies over the region.
Xavier Fettweis, Stefan Hofer, Roland Séférian, Charles Amory, Alison Delhasse, Sébastien Doutreloup, Christoph Kittel, Charlotte Lang, Joris Van Bever, Florent Veillon, and Peter Irvine
The Cryosphere, 15, 3013–3019,Short summary
Without any reduction in our greenhouse gas emissions, the Greenland ice sheet surface mass loss can be brought in line with a medium-mitigation emissions scenario by reducing the solar downward flux at the top of the atmosphere by 1.5 %. In addition to reducing global warming, these solar geoengineering measures also dampen the well-known positive melt–albedo feedback over the ice sheet by 6 %. However, only stronger reductions in solar radiation could maintain a stable ice sheet in 2100.
Paolo Colosio, Marco Tedesco, Roberto Ranzi, and Xavier Fettweis
The Cryosphere, 15, 2623–2646,Short summary
We use a new satellite dataset to study the spatiotemporal evolution of surface melting over Greenland at an enhanced resolution of 3.125 km. Using meteorological data and the MAR model, we observe that a dynamic algorithm can best detect surface melting. We found that the melting season is elongating, the melt extent is increasing and that high-resolution data better describe the spatiotemporal evolution of the melting season, which is crucial to improve estimates of sea level rise.
Charles Amory, Christoph Kittel, Louis Le Toumelin, Cécile Agosta, Alison Delhasse, Vincent Favier, and Xavier Fettweis
Geosci. Model Dev., 14, 3487–3510,Short summary
This paper presents recent developments in the drifting-snow scheme of the regional climate model MAR and its application to simulate drifting snow and the surface mass balance of Adélie Land in East Antarctica. The model is extensively described and evaluated against a multi-year drifting-snow dataset and surface mass balance estimates available in the area. The model sensitivity to input parameters and improvements over a previously published version are also assessed.
Kenneth D. Mankoff, Xavier Fettweis, Peter L. Langen, Martin Stendel, Kristian K. Kjledsen, Nanna B. Karlsson, Brice Noël, Michiel R. van den Broeke, Wiliam Colgan, Sebastian B. Simonsen, Jason E. Box, Anne Solgaard, Andreas P. Ahlstrøm, Signe Bech Andersen, and Robert S. Fausto
Earth Syst. Sci. Data Discuss.,
Revised manuscript under review for ESSDShort summary
We estimate the daily mass balance, and its components (surface, marine, and basal mass balance) for the Greenland ice sheet. Our time series begins in 1840 and has annual resolution through 1985, and then daily from 1986 through next week. Results are provided for the entire GIS, or by commonly-used regions or sectors. This is the first input/output mass balance estimate to include the basal mass balance.
Matthew G. Cooper, Laurence C. Smith, Asa K. Rennermalm, Marco Tedesco, Rohi Muthyala, Sasha Z. Leidman, Samiah E. Moustafa, and Jessica V. Fayne
The Cryosphere, 15, 1931–1953,Short summary
We measured sunlight transmitted into glacier ice to improve models of glacier ice melt and satellite measurements of glacier ice surfaces. We found that very small concentrations of impurities inside the ice increase absorption of sunlight, but the amount was small enough to enable an estimate of ice absorptivity. We confirmed earlier results that the absorption minimum is near 390 nm. We also found that a layer of highly reflective granular "white ice" near the surface reduces transmittance.
Christoph Kittel, Charles Amory, Cécile Agosta, Nicolas C. Jourdain, Stefan Hofer, Alison Delhasse, Sébastien Doutreloup, Pierre-Vincent Huot, Charlotte Lang, Thierry Fichefet, and Xavier Fettweis
The Cryosphere, 15, 1215–1236,Short summary
The future surface mass balance (SMB) of the Antarctic ice sheet (AIS) will influence the ice dynamics and the contribution of the ice sheet to the sea level rise. We investigate the AIS sensitivity to different warmings using physical and statistical downscaling of CMIP5 and CMIP6 models. Our results highlight a contrasting effect between the grounded ice sheet (where the SMB is projected to increase) and ice shelves (where the future SMB depends on the emission scenario).
Martin Ménégoz, Evgenia Valla, Nicolas C. Jourdain, Juliette Blanchet, Julien Beaumet, Bruno Wilhelm, Hubert Gallée, Xavier Fettweis, Samuel Morin, and Sandrine Anquetin
Hydrol. Earth Syst. Sci., 24, 5355–5377,Short summary
The study investigates precipitation changes in the Alps, using observations and a 7 km resolution climate simulation over 1900–2010. An increase in mean precipitation is found in winter over the Alps, whereas a drying occurred in summer in the surrounding plains. A general increase in the daily annual maximum of precipitation is evidenced (20 to 40 % per century), suggesting an increase in extreme events that is significant only when considering long time series, typically 50 to 80 years.
Kenneth D. Mankoff, Brice Noël, Xavier Fettweis, Andreas P. Ahlstrøm, William Colgan, Ken Kondo, Kirsty Langley, Shin Sugiyama, Dirk van As, and Robert S. Fausto
Earth Syst. Sci. Data, 12, 2811–2841,Short summary
This work partitions regional climate model (RCM) runoff from the MAR and RACMO RCMs to hydrologic outlets at the ice margin and coast. Temporal resolution is daily from 1959 through 2019. Spatial grid is ~ 100 m, resolving individual streams. In addition to discharge at outlets, we also provide the streams, outlets, and basin geospatial data, as well as a script to query and access the geospatial or time series discharge data from the data files.
Xavier Fettweis, Stefan Hofer, Uta Krebs-Kanzow, Charles Amory, Teruo Aoki, Constantijn J. Berends, Andreas Born, Jason E. Box, Alison Delhasse, Koji Fujita, Paul Gierz, Heiko Goelzer, Edward Hanna, Akihiro Hashimoto, Philippe Huybrechts, Marie-Luise Kapsch, Michalea D. King, Christoph Kittel, Charlotte Lang, Peter L. Langen, Jan T. M. Lenaerts, Glen E. Liston, Gerrit Lohmann, Sebastian H. Mernild, Uwe Mikolajewicz, Kameswarrao Modali, Ruth H. Mottram, Masashi Niwano, Brice Noël, Jonathan C. Ryan, Amy Smith, Jan Streffing, Marco Tedesco, Willem Jan van de Berg, Michiel van den Broeke, Roderik S. W. van de Wal, Leo van Kampenhout, David Wilton, Bert Wouters, Florian Ziemen, and Tobias Zolles
The Cryosphere, 14, 3935–3958,Short summary
We evaluated simulated Greenland Ice Sheet surface mass balance from 5 kinds of models. While the most complex (but expensive to compute) models remain the best, the faster/simpler models also compare reliably with observations and have biases of the same order as the regional models. Discrepancies in the trend over 2000–2012, however, suggest that large uncertainties remain in the modelled future SMB changes as they are highly impacted by the meltwater runoff biases over the current climate.
Kang Yang, Aleah Sommers, Lauren C. Andrews, Laurence C. Smith, Xin Lu, Xavier Fettweis, and Manchun Li
The Cryosphere, 14, 3349–3365,Short summary
This study compares hourly supraglacial moulin discharge simulations from three surface meltwater routing models. Results show that these models are superior to simply using regional climate model runoff without routing, but different routing models, different-spatial-resolution DEMs, and parameterized seasonal evolution of supraglacial stream and river networks induce significant variability in diurnal moulin discharges and corresponding subglacial effective pressures.
Heiko Goelzer, Sophie Nowicki, Anthony Payne, Eric Larour, Helene Seroussi, William H. Lipscomb, Jonathan Gregory, Ayako Abe-Ouchi, Andrew Shepherd, Erika Simon, Cécile Agosta, Patrick Alexander, Andy Aschwanden, Alice Barthel, Reinhard Calov, Christopher Chambers, Youngmin Choi, Joshua Cuzzone, Christophe Dumas, Tamsin Edwards, Denis Felikson, Xavier Fettweis, Nicholas R. Golledge, Ralf Greve, Angelika Humbert, Philippe Huybrechts, Sebastien Le clec'h, Victoria Lee, Gunter Leguy, Chris Little, Daniel P. Lowry, Mathieu Morlighem, Isabel Nias, Aurelien Quiquet, Martin Rückamp, Nicole-Jeanne Schlegel, Donald A. Slater, Robin S. Smith, Fiamma Straneo, Lev Tarasov, Roderik van de Wal, and Michiel van den Broeke
The Cryosphere, 14, 3071–3096,Short summary
In this paper we use a large ensemble of Greenland ice sheet models forced by six different global climate models to project ice sheet changes and sea-level rise contributions over the 21st century. The results for two different greenhouse gas concentration scenarios indicate that the Greenland ice sheet will continue to lose mass until 2100, with contributions to sea-level rise of 90 ± 50 mm and 32 ± 17 mm for the high (RCP8.5) and low (RCP2.6) scenario, respectively.
Sophie Nowicki, Heiko Goelzer, Hélène Seroussi, Anthony J. Payne, William H. Lipscomb, Ayako Abe-Ouchi, Cécile Agosta, Patrick Alexander, Xylar S. Asay-Davis, Alice Barthel, Thomas J. Bracegirdle, Richard Cullather, Denis Felikson, Xavier Fettweis, Jonathan M. Gregory, Tore Hattermann, Nicolas C. Jourdain, Peter Kuipers Munneke, Eric Larour, Christopher M. Little, Mathieu Morlighem, Isabel Nias, Andrew Shepherd, Erika Simon, Donald Slater, Robin S. Smith, Fiammetta Straneo, Luke D. Trusel, Michiel R. van den Broeke, and Roderik van de Wal
The Cryosphere, 14, 2331–2368,Short summary
This paper describes the experimental protocol for ice sheet models taking part in the Ice Sheet Model Intercomparion Project for CMIP6 (ISMIP6) and presents an overview of the atmospheric and oceanic datasets to be used for the simulations. The ISMIP6 framework allows for exploring the uncertainty in 21st century sea level change from the Greenland and Antarctic ice sheets.
Heiko Goelzer, Brice P. Y. Noël, Tamsin L. Edwards, Xavier Fettweis, Jonathan M. Gregory, William H. Lipscomb, Roderik S. W. van de Wal, and Michiel R. van den Broeke
The Cryosphere, 14, 1747–1762,Short summary
Future sea-level change projections with process-based ice sheet models are typically driven with surface mass balance forcing derived from climate models. In this work we address the problems arising from a mismatch of the modelled ice sheet geometry with the one used by the climate model. The proposed remapping method reproduces the original forcing data closely when applied to the original geometry and produces a physically meaningful forcing when applied to different modelled geometries.
Colleen Mortimer, Lawrence Mudryk, Chris Derksen, Kari Luojus, Ross Brown, Richard Kelly, and Marco Tedesco
The Cryosphere, 14, 1579–1594,Short summary
Existing stand-alone passive microwave SWE products have markedly different climatological SWE patterns compared to reanalysis-based datasets. The AMSR-E SWE has low spatial and temporal correlations with the four reanalysis-based products evaluated and GlobSnow and perform poorly in comparisons with snow transect data from Finland, Russia, and Canada. There is better agreement with in situ data when multiple SWE products, excluding the stand-alone passive microwave SWE products, are combined.
Marco Tedesco and Xavier Fettweis
The Cryosphere, 14, 1209–1223,Short summary
Unprecedented atmospheric conditions occurring in the summer of 2019 over Greenland promoted new record or close-to-record values of mass loss. Summer of 2019 was characterized by an exceptional persistence of anticyclonic conditions that enhanced melting.
Marco Tedesco, Steven McAlpine, and Jeremy R. Porter
Nat. Hazards Earth Syst. Sci., 20, 907–920,Short summary
Quantifying the exposure of house property to extreme weather events is crucial to study their impact on economy. Here, we show that value of property exposed to Hurricane Florence in September 2018 was USD 52 billion vs. USD 10 billion that would have occurred at the beginning of the 19th century due to urban expansion that increased after 1950s and the increasing number of houses built near water, showing the importance of accounting for the distribution of new buildings in risk and exposure.
Donald A. Slater, Denis Felikson, Fiamma Straneo, Heiko Goelzer, Christopher M. Little, Mathieu Morlighem, Xavier Fettweis, and Sophie Nowicki
The Cryosphere, 14, 985–1008,Short summary
Changes in the ocean around Greenland play an important role in determining how much the ice sheet will contribute to global sea level over the coming century. However, capturing these links in models is very challenging. This paper presents a strategy enabling an ensemble of ice sheet models to feel the effect of the ocean for the first time and should therefore result in a significant improvement in projections of the Greenland ice sheet's contribution to future sea level change.
Alison Delhasse, Christoph Kittel, Charles Amory, Stefan Hofer, Dirk van As, Robert S. Fausto, and Xavier Fettweis
The Cryosphere, 14, 957–965,Short summary
The ERA5 reanalysis of the ECMWF replaced the ERA-Interim in August 2019 and has never been evaluated over Greenland. The aim was to evaluate the performance of ERA5 to simulate the near-surface climate of the Greenland Ice sheet (GrIS) against ERA-Interim and regional climate models with the help of in situ observations from the PROMICE dataset. We also highlighted that polar regional climate models are still a useful tool to study the GrIS climate compared to ERA5.
Alison Delhasse, Edward Hanna, Christoph Kittel, and Xavier Fettweis
The Cryosphere Discuss.,
Preprint withdrawnShort summary
Significant melting events over Greenland ice sheet related to unusual atmospheric pattern in summer, as observed this summer 2019, are still not considered by the new generation of Earth-system models (CMIP6) and therefore the projected surface melt increase of the ice sheet is likely to be underestimated if such changes persist in the next decades.
Marion Donat-Magnin, Nicolas C. Jourdain, Hubert Gallée, Charles Amory, Christoph Kittel, Xavier Fettweis, Jonathan D. Wille, Vincent Favier, Amine Drira, and Cécile Agosta
The Cryosphere, 14, 229–249,Short summary
Modeling the interannual variability of the surface conditions over Antarctic glaciers is important for the identification of climate trends and climate predictions and to assess models. We simulate snow accumulation and surface melting in the Amundsen sector (West Antarctica) over 1979–2017. For all the glaciers, the interannual variability of summer snow accumulation and surface melting is driven by two distinct mechanisms related to variations in the Amundsen Sea Low strength and position.
Donald A. Slater, Fiamma Straneo, Denis Felikson, Christopher M. Little, Heiko Goelzer, Xavier Fettweis, and James Holte
The Cryosphere, 13, 2489–2509,Short summary
The ocean's influence on the retreat of Greenland's tidewater glaciers is a key factor determining future sea level. By considering observations of ~200 glaciers from 1960, we find a significant relationship between retreat and melting in the ocean. Projected forwards, this relationship estimates the future evolution of Greenland's tidewater glaciers and provides a practical and empirically validated way of representing ice–ocean interaction in large-scale models used to estimate sea level rise.
Thomas J. Ballinger, Thomas L. Mote, Kyle Mattingly, Angela C. Bliss, Edward Hanna, Dirk van As, Melissa Prieto, Saeideh Gharehchahi, Xavier Fettweis, Brice Noël, Paul C. J. P. Smeets, Carleen H. Reijmer, Mads H. Ribergaard, and John Cappelen
The Cryosphere, 13, 2241–2257,Short summary
Arctic sea ice and the Greenland Ice Sheet (GrIS) are melting later in the year due to a warming climate. Through analyses of weather station, climate model, and reanalysis data, physical links are evaluated between Baffin Bay open water duration and western GrIS melt conditions. We show that sub-Arctic air mass movement across this portion of the GrIS strongly influences late summer and autumn melt, while near-surface, off-ice winds inhibit westerly atmospheric heat transfer from Baffin Bay.
Marilena Oltmanns, Fiammetta Straneo, and Marco Tedesco
The Cryosphere, 13, 815–825,Short summary
By combining reanalysis, weather station and satellite data, we show that increases in surface melt over Greenland are initiated by large-scale precipitation events year-round. Estimates from a regional climate model suggest that the initiated melting more than doubled between 1988 and 2012, amounting to ~28 % of the overall melt and revealing that, despite the involved mass gain, precipitation events are contributing to the ice sheet's decline.
Sébastien Le clec'h, Sylvie Charbit, Aurélien Quiquet, Xavier Fettweis, Christophe Dumas, Masa Kageyama, Coraline Wyard, and Catherine Ritz
The Cryosphere, 13, 373–395,Short summary
Quantifying the future contribution of the Greenland ice sheet (GrIS) to sea-level rise in response to atmospheric changes is important but remains challenging. For the first time a full representation of the feedbacks between a GrIS model and a regional atmospheric model was implemented. The authors highlight the fundamental need for representing the GrIS topography change feedbacks with respect to the atmospheric component face to the strong impact on the projected sea-level rise.
Cécile Agosta, Charles Amory, Christoph Kittel, Anais Orsi, Vincent Favier, Hubert Gallée, Michiel R. van den Broeke, Jan T. M. Lenaerts, Jan Melchior van Wessem, Willem Jan van de Berg, and Xavier Fettweis
The Cryosphere, 13, 281–296,Short summary
Antarctic surface mass balance (ASMB), a component of the sea level budget, is commonly estimated through modelling as observations are scarce. The polar-oriented regional climate model MAR performs well in simulating the observed ASMB. MAR and RACMO2 share common biases we relate to drifting snow transport, with a 3 times larger magnitude than in previous estimates. Sublimation of precipitation in the katabatic layer modelled by MAR is of a magnitude similar to an observation-based estimate.
Christoph Kittel, Charles Amory, Cécile Agosta, Alison Delhasse, Sébastien Doutreloup, Pierre-Vincent Huot, Coraline Wyard, Thierry Fichefet, and Xavier Fettweis
The Cryosphere, 12, 3827–3839,Short summary
Regional climate models (RCMs) used to estimate the surface mass balance (SMB) of Antarctica depend on boundary forcing fields including sea surface conditions. Here, we assess the sensitivity of the Antarctic SMB to perturbations in sea surface conditions with the RCM MAR using unchanged atmospheric conditions. Significant SMB anomalies are found for SSC perturbations in the range of CMIP5 global climate model biases.
Kang Yang, Laurence C. Smith, Leif Karlstrom, Matthew G. Cooper, Marco Tedesco, Dirk van As, Xiao Cheng, Zhuoqi Chen, and Manchun Li
The Cryosphere, 12, 3791–3811,Short summary
A high-resolution spatially lumped hydrologic surface routing model is proposed to simulate meltwater transport over bare ice surfaces. In an ice-covered catchment, meltwater is routed by slow interfluve flow (~10−3–10−4 m s−1) followed by fast open-channel flow (~10−1 m s−1). Seasonal evolution of supraglacial stream-river networks substantially alters the magnitude and timing of moulin discharge with implications for subglacial hydrology and ice dynamics.
Alison Delhasse, Xavier Fettweis, Christoph Kittel, Charles Amory, and Cécile Agosta
The Cryosphere, 12, 3409–3418,Short summary
Since the 2000s, an atmospheric circulation change (CC) gauged by a negative summer shift in the North Atlantic Oscillation has been observed, enhancing surface melt over the Greenland Ice Sheet (GrIS). Future GrIS surface mass balance (SMB) projections are based on global climate models that do not represent this CC. The model MAR has been used to show that previous estimates of these projections could have been significantly overestimated if this current circulation pattern persists.
Lynn Montgomery, Lora Koenig, and Patrick Alexander
Earth Syst. Sci. Data, 10, 1959–1985,Short summary
The SUMup dataset is a standardized, expandable, community dataset of Arctic and Antarctic observations of surface mass balance components, including snow/firn density, snow accumulation on land ice, and snow depth on sea ice. The measurements in this dataset were compiled from field notes, papers, technical reports, and digital files. We use these observations to monitor change in the polar regions and evaluate model output as well as remote sensing measurements.
Edward Hanna, Xavier Fettweis, and Richard J. Hall
The Cryosphere, 12, 3287–3292,Short summary
The latest/recent generations of global climate models do not simulate the recent (last 30 years) increase in atmospheric high pressure over Greenland in summer but rather projects decreasing pressure. This difference between climate models and observations raises serious questions about the ability of the models to accurately represent future changes in Greenland climate and ice-sheet mass balance. There are also likely effects on climate predictions downstream, e.g. over Europe.
Jiangjun Ran, Miren Vizcaino, Pavel Ditmar, Michiel R. van den Broeke, Twila Moon, Christian R. Steger, Ellyn M. Enderlin, Bert Wouters, Brice Noël, Catharina H. Reijmer, Roland Klees, Min Zhong, Lin Liu, and Xavier Fettweis
The Cryosphere, 12, 2981–2999,Short summary
To accurately predict future sea level rise, the mechanisms driving the observed mass loss must be better understood. Here, we combine data from the satellite gravimetry, surface mass balance, and ice discharge to analyze the mass budget of Greenland at various temporal scales. This study, for the first time, suggests the existence of a substantial meltwater storage during summer, with a peak value of 80–120 Gt in July. We highlight its importance for understanding ice sheet mass variability
Rajashree Tri Datta, Marco Tedesco, Cecile Agosta, Xavier Fettweis, Peter Kuipers Munneke, and Michiel R. van den Broeke
The Cryosphere, 12, 2901–2922,Short summary
Surface melting on the East Antarctic Peninsula (East AP) has been linked to ice shelf collapse, including the Larsen A (1995) and Larsen B (2002) ice shelves. Regional climate models (RCMs) are a valuable tool to understand how wind patterns and general warming can impact the stability of ice shelves through surface melt. Here, we evaluate one such RCM (Modèle Atmosphérique Régionale) over the East AP, including the remaining Larsen C ice shelf, by comparing it to satellite and ground data.
Achim Heilig, Olaf Eisen, Michael MacFerrin, Marco Tedesco, and Xavier Fettweis
The Cryosphere, 12, 1851–1866,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.
Amber A. Leeson, Emma Eastoe, and Xavier Fettweis
The Cryosphere, 12, 1091–1102,Short summary
Future melting of the Greenland Ice Sheet is predicted using regional climate models (RCMs). Here, we assess the ability of the MAR RCM to reproduce observed extreme temperature events and the melt energy produced during these times at 14 locations. We find that MAR underestimates temperatures by >0.5 °C during extreme events, which leads to an underestimate in melt energy by up to 41 %. This is potentially an artefact of the data used to drive the MAR simulation and needs to be corrected for.
Andrew J. Tedstone, Jonathan L. Bamber, Joseph M. Cook, Christopher J. Williamson, Xavier Fettweis, Andrew J. Hodson, and Martyn Tranter
The Cryosphere, 11, 2491–2506,Short summary
The bare ice albedo of the south-west Greenland ice sheet varies dramatically between years. The reasons are unclear but likely involve darkening by inorganic particulates, cryoconite and ice algae. We use satellite imagery to examine dark ice dynamics and climate model outputs to find likely climatological controls. Outcropping particulates can explain the spatial extent of dark ice, but the darkening itself is likely due to ice algae growth controlled by meltwater and light availability.
Julienne C. Stroeve, John R. Mioduszewski, Asa Rennermalm, Linette N. Boisvert, Marco Tedesco, and David Robinson
The Cryosphere, 11, 2363–2381,Short summary
As the sea ice has declined strongly in recent years there has been a corresponding increase in Greenland melting. While both are likely a result of changes in atmospheric circulation patterns that favor summer melt, this study evaluates whether or not sea ice reductions around the Greenland ice sheet are having an influence on Greenland summer melt through enhanced sensible and latent heat transport from open water areas onto the ice sheet.
Johannes Jakob Fürst, Fabien Gillet-Chaulet, Toby J. Benham, Julian A. Dowdeswell, Mariusz Grabiec, Francisco Navarro, Rickard Pettersson, Geir Moholdt, Christopher Nuth, Björn Sass, Kjetil Aas, Xavier Fettweis, Charlotte Lang, Thorsten Seehaus, and Matthias Braun
The Cryosphere, 11, 2003–2032,Short summary
For the large majority of glaciers and ice caps, there is no information on the thickness of the ice cover. Any attempt to predict glacier demise under climatic warming and to estimate the future contribution to sea-level rise is limited as long as the glacier thickness is not well constrained. Here, we present a two-step mass-conservation approach for mapping ice thickness. Measurements are naturally reproduced. The reliability is readily assessible from a complementary map of error estimates.
Kimberly A. Casey, Chris M. Polashenski, Justin Chen, and Marco Tedesco
The Cryosphere, 11, 1781–1795,Short summary
We analyzed Greenland Ice Sheet (GrIS) average summer surface reflectance and albedo (2001–2016). MODIS Collection 6 data show a decreased magnitude of change over time due to sensor calibration corrections. Spectral band maps provide insight into GrIS surface processes likely occurring. Correctly measuring albedo and surface reflectance changes over time is crucial to monitoring atmosphere–ice interactions and ice mass balance. The results are applicable to many long-term MODIS studies.
Xavier Fettweis, Jason E. Box, Cécile Agosta, Charles Amory, Christoph Kittel, Charlotte Lang, Dirk van As, Horst Machguth, and Hubert Gallée
The Cryosphere, 11, 1015–1033,Short summary
This paper shows that the surface melt increase over the Greenland ice sheet since the end of the 1990s has been unprecedented, with respect to the last 120 years, using a regional climate model. These simulations also suggest an increase of the snowfall accumulation through the last century before a surface mass decrease in the 2000s. Such a mass gain could have impacted the ice sheet's dynamic stability and could explain the recent observed increase of the glaciers' velocity.
Brice Noël, Willem Jan van de Berg, Horst Machguth, Stef Lhermitte, Ian Howat, Xavier Fettweis, and Michiel R. van den Broeke
The Cryosphere, 10, 2361–2377,Short summary
We present a 1 km resolution data set (1958–2015) of daily Greenland ice sheet surface mass balance (SMB), statistically downscaled from the data of RACMO2.3 at 11 km using elevation dependence, precipitation and bare ice albedo corrections. The data set resolves Greenland narrow ablation zones and local outlet glaciers, and shows more realistic SMB patterns, owing to enhanced runoff at the ice sheet margins. An evaluation of the product against SMB measurements shows improved agreement.
Nicole-Jeanne Schlegel, David N. Wiese, Eric Y. Larour, Michael M. Watkins, Jason E. Box, Xavier Fettweis, and Michiel R. van den Broeke
The Cryosphere, 10, 1965–1989,Short summary
We investigate Greenland Ice Sheet mass change from 2003–2012 by comparing observations from GRACE with state-of-the-art atmospheric and ice sheet model simulations. We find that the largest discrepancies (in the northwest and southeast) are likely controlled by errors in modeled surface climate as well as ice–ocean interaction and hydrological processes (not included in the models). Models should consider such processes at monthly to seasonal resolutions in order to improve future projections.
Lora S. Koenig, Alvaro Ivanoff, Patrick M. Alexander, Joseph A. MacGregor, Xavier Fettweis, Ben Panzer, John D. Paden, Richard R. Forster, Indrani Das, Joesph R. McConnell, Marco Tedesco, Carl Leuschen, and Prasad Gogineni
The Cryosphere, 10, 1739–1752,Short summary
Contemporary climate warming over the Arctic is accelerating mass loss from the Greenland Ice Sheet through increasing surface melt, emphasizing the need to closely monitor surface mass balance in order to improve sea-level rise predictions. Here, we quantify the net annual accumulation over the Greenland Ice Sheet, which comprises the largest component of surface mass balance, at a higher spatial resolution than currently available using high-resolution, airborne-radar data.
Patrick M. Alexander, Marco Tedesco, Nicole-Jeanne Schlegel, Scott B. Luthcke, Xavier Fettweis, and Eric Larour
The Cryosphere, 10, 1259–1277,Short summary
We compared satellite-derived estimates of spatial and seasonal variations in Greenland Ice Sheet mass with a set of model simulations, revealing an agreement between models and satellite estimates for the ice-sheet-wide seasonal fluctuations in mass, but disagreement at finer spatial scales. The model simulations underestimate low-elevation mass loss. Improving the ability of models to capture variations and trends in Greenland Ice Sheet mass is important for estimating future sea level rise.
Marco Tedesco, Sarah Doherty, Xavier Fettweis, Patrick Alexander, Jeyavinoth Jeyaratnam, and Julienne Stroeve
The Cryosphere, 10, 477–496,Short summary
Summer surface albedo over Greenland decreased at a rate of 0.02 per decade between 1996 and 2012. The decrease is due to snow grain growth, the expansion of bare ice areas, and trends in light-absorbing impurities on snow and ice surfaces. Neither aerosol models nor in situ observations indicate increasing trends in impurities in the atmosphere over Greenland. Albedo projections through to the end of the century under different warming scenarios consistently point to continued darkening.
M. Navari, S. A. Margulis, S. M. Bateni, M. Tedesco, P. Alexander, and X. Fettweis
The Cryosphere, 10, 103–120,Short summary
An ensemble batch smoother was used to assess the feasibility of generating a reanalysis estimate of the Greenland ice sheet (GrIS) surface mass fluxes (SMF) via integrating measured ice surface temperatures with a regional climate model estimate. The results showed that assimilation of IST were able to overcome uncertainties in meteorological forcings that drive the GrIS surface processes. We showed that the proposed methodology is able to generate posterior reanalysis estimates of the SMF.
C. Agosta, X. Fettweis, and R. Datta
The Cryosphere, 9, 2311–2321,Short summary
Estimates of the Antarctic surface mass balance with regional climate models (RCMs) require proper fields for forcing; hence we evaluate 41 CMIP5 climate models over Antarctica and include six reanalyses. Most of the models are biased compared to ERA-Interim, ACCESS1-3 being the best choice for forcing RCMs. Climate change is less sensitive to global warming than it is to the present-day simulated sea ice and to the feedback between sea-ice decrease and temperature increase around Antarctica.
V. Masson-Delmotte, H. C. Steen-Larsen, P. Ortega, D. Swingedouw, T. Popp, B. M. Vinther, H. Oerter, A. E. Sveinbjornsdottir, H. Gudlaugsdottir, J. E. Box, S. Falourd, X. Fettweis, H. Gallée, E. Garnier, V. Gkinis, J. Jouzel, A. Landais, B. Minster, N. Paradis, A. Orsi, C. Risi, M. Werner, and J. W. C. White
The Cryosphere, 9, 1481–1504,Short summary
The deep NEEM ice core provides the oldest Greenland ice core record, enabling improved understanding of the response of ice core records to local climate. Here, we focus on shallow ice cores providing a stack record of accumulation and water-stable isotopes spanning the past centuries. For the first time, we document the ongoing warming in a Greenland ice core. By combining our data with other Greenland ice cores and model results, we characterise the spatio-temporal patterns of variability.
C. Lang, X. Fettweis, and M. Erpicum
The Cryosphere, 9, 945–956,Short summary
We simulated the 21st century Svalbard SMB with the regional model MAR (RCP8.5 scenario). Melt is projected to increase gently up to 2050 and then dramatically increase, with a larger increase in the south of the archipelago. This difference is due to larger ice albedo decrease in the south causing larger increase of absorbed solar radiation. The ablation area is projected to disappear over the entire Svalbard by 2085. The SMB decrease compared to present is projected to contribute 7mm to SLR.
C. Lang, X. Fettweis, and M. Erpicum
The Cryosphere, 9, 83–101,Short summary
We have modelled the surface mass balance (SMB) of Svalbard with the model MAR over 1979--2013. The mean SMB is slightly negative and the Svalbard glaciers are losing mass through surface processes (mainly precipitation and runoff), but there has been no acceleration of the surface melt, contrary to Greenland where melt records have been broken since 2006. We attributed it to a change in atmospheric circulation, resulting in northerly cold flows over Svalbard damping Arctic warming.
A. Belleflamme, X. Fettweis, and M. Erpicum
The Cryosphere, 9, 53–64,Short summary
The 2007-2012 summertime circulation anomaly over the Arctic region (i.e. more high pressure systems over the Beaufort Sea, the Canadian Arctic Archipelago, and Greenland) is put in a historical perspective. While the 2007-2012 anomaly seems to be exceptional, similar circulation conditions have occurred since 1871, on the basis of five reanalyses (ERA-Interim, ERA-40, NCEP/NCAR, ERA-20C, 20CRv2). The attribution of this anomaly (natural variability or global warming) remains debatable.
P. M. Alexander, M. Tedesco, X. Fettweis, R. S. W. van de Wal, C. J. P. P. Smeets, and M. R. van den Broeke
The Cryosphere, 8, 2293–2312,
B. Noël, X. Fettweis, W. J. van de Berg, M. R. van den Broeke, and M. Erpicum
The Cryosphere, 8, 1871–1883,
C. J. Legleiter, M. Tedesco, L. C. Smith, A. E. Behar, and B. T. Overstreet
The Cryosphere, 8, 215–228,
T. L. Edwards, X. Fettweis, O. Gagliardini, F. Gillet-Chaulet, H. Goelzer, J. M. Gregory, M. Hoffman, P. Huybrechts, A. J. Payne, M. Perego, S. Price, A. Quiquet, and C. Ritz
The Cryosphere, 8, 181–194,
T. L. Edwards, X. Fettweis, O. Gagliardini, F. Gillet-Chaulet, H. Goelzer, J. M. Gregory, M. Hoffman, P. Huybrechts, A. J. Payne, M. Perego, S. Price, A. Quiquet, and C. Ritz
The Cryosphere, 8, 195–208,
W. Colgan, W. Abdalati, M. Citterio, B. Csatho, X. Fettweis, S. Luthcke, G. Moholdt, and M. Stober
The Cryosphere Discuss.,
Revised manuscript not accepted
M. Tedesco, X. Fettweis, T. Mote, J. Wahr, P. Alexander, J. E. Box, and B. Wouters
The Cryosphere, 7, 615–630,
C. L. Vernon, J. L. Bamber, J. E. Box, M. R. van den Broeke, X. Fettweis, E. Hanna, and P. Huybrechts
The Cryosphere, 7, 599–614,
X. Fettweis, B. Franco, M. Tedesco, J. H. van Angelen, J. T. M. Lenaerts, M. R. van den Broeke, and H. Gallée
The Cryosphere, 7, 469–489,
X. Fettweis, E. Hanna, C. Lang, A. Belleflamme, M. Erpicum, and H. Gallée
The Cryosphere, 7, 241–248,
B. Franco, X. Fettweis, and M. Erpicum
The Cryosphere, 7, 1–18,
Related subject area
Discipline: Ice sheets | Subject: Remote SensingBrief communication: Ice sheet elevation measurements from the Sentinel-3A and Sentinel-3B tandem phasePenetration of interferometric radar signals in Antarctic snowUsing ICESat-2 and Operation IceBridge altimetry for supraglacial lake depth retrievalsBrief communication: Mapping Greenland's perennial firn aquifers using enhanced-resolution L-band brightness temperature image time seriesAerogeophysical characterization of an active subglacial lake system in the David Glacier catchment, AntarcticaMeasuring the location and width of the Antarctic grounding zone using CryoSat-2Brief Communication: Update on the GPS reflection technique for measuring snow accumulation in GreenlandImproved GNSS-R bi-static altimetry and independent digital elevation models of Greenland and Antarctica from TechDemoSat-1Melt in Antarctica derived from Soil Moisture and Ocean Salinity (SMOS) observations at L bandSentinel-3 Delay-Doppler altimetry over AntarcticaThe Reference Elevation Model of AntarcticaAssessment of altimetry using ground-based GPS data from the 88S Traverse, Antarctica, in support of ICESat-2Dual-satellite (Sentinel-2 and Landsat 8) remote sensing of supraglacial lakes in GreenlandCoherent large beamwidth processing of radio-echo sounding dataMulti-channel and multi-polarization radar measurements around the NEEM siteSeasonal variations of the backscattering coefficient measured by radar altimeters over the Antarctic Ice SheetRecent dynamic changes on Fleming Glacier after the disintegration of Wordie Ice Shelf, Antarctic Peninsula
Malcolm McMillan, Alan Muir, and Craig Donlon
The Cryosphere, 15, 3129–3134,Short summary
We evaluate the consistency of ice sheet elevation measurements made by two satellites: Sentinel-3A and Sentinel-3B. We analysed data from the unique
tandemphase of the mission, where the two satellites flew 30 s apart to provide near-instantaneous measurements of Earth's surface. Analysing these data over Antarctica, we find no significant difference between the satellites, which is important for demonstrating that they can be used interchangeably for long-term ice sheet monitoring.
Helmut Rott, Stefan Scheiblauer, Jan Wuite, Lukas Krieger, Dana Floricioiu, Paola Rizzoli, Ludivine Libert, and Thomas Nagler
The Cryosphere Discuss.,
Revised manuscript accepted for TCShort summary
We studied relations between interferometric radar (InSAR) signals and snow properties and evaluated procedures for deriving the penetration bias of InSAR DEMs by inverting the signal coherence. Study site is Union Glacier in Antarctica. The data base comprises InSAR data of the TanDEM-X mission, topographic data from optical sensors and field measurements. The paper provides new insights on interferometric signal interactions with polar snow and on methods for correcting the penetration bias.
Zachary Fair, Mark Flanner, Kelly M. Brunt, Helen Amanda Fricker, and Alex Gardner
The Cryosphere, 14, 4253–4263,Short summary
Ice on glaciers and ice sheets may melt and pond on ice surfaces in summer months. Detection and observation of these meltwater ponds is important for understanding glaciers and ice sheets, and satellite imagery has been used in previous work. However, image-based methods struggle with deep water, so we used data from the Ice, Clouds, and land Elevation Satellite-2 (ICESat-2) and the Airborne Topographic Mapper (ATM) to demonstrate the potential for lidar depth monitoring.
Julie Z. Miller, David G. Long, Kenneth C. Jezek, Joel T. Johnson, Mary J. Brodzik, Christopher A. Shuman, Lora S. Koenig, and Ted A. Scambos
The Cryosphere, 14, 2809–2817,
Laura E. Lindzey, Lucas H. Beem, Duncan A. Young, Enrica Quartini, Donald D. Blankenship, Choon-Ki Lee, Won Sang Lee, Jong Ik Lee, and Joohan Lee
The Cryosphere, 14, 2217–2233,Short summary
An extensive aerogeophysical survey including two active subglacial lakes was conducted over David Glacier, Antarctica. Laser altimetry shows that the lakes were at a highstand, while ice-penetrating radar has no unique signature for the lakes when compared to the broader basal environment. This suggests that active subglacial lakes are more likely to be part of a distributed subglacial hydrological system than to be discrete reservoirs, which has implications for future surveys and drilling.
Geoffrey J. Dawson and Jonathan L. Bamber
The Cryosphere, 14, 2071–2086,Short summary
The grounding zone is where grounded ice begins to float and is the boundary at which the ocean has the most significant influence on the inland ice sheet. Here, we present the results of mapping the grounding zone of Antarctic ice shelves from CryoSat-2 radar altimetry. We found good agreement with previous methods that mapped the grounding zone. We also managed to map areas of Support Force Glacier and the Doake Ice Rumples (Filchner–Ronne Ice Shelf), which were previously incompletely mapped.
Kristine M. Larson, Michael MacFerrin, and Thomas Nylen
The Cryosphere, 14, 1985–1988,Short summary
Reflected GPS signals can be used to measure snow accumulation. The GPS method is accurate and has a footprint that is larger than that of many other methods. This short note makes available 9 years of daily snow accumulation measurements from Greenland that were derived from reflected GPS signals. It also provides information about open-source software that the cryosphere community can use to analyze other datasets.
Jessica Cartwright, Christopher J. Banks, and Meric Srokosz
The Cryosphere, 14, 1909–1917,Short summary
This study uses reflected GPS signals to measure ice at the South Pole itself for the first time. These measurements are essential to understand the interaction of the ice with the Earth’s physical systems. Orbital constraints mean that satellites are usually unable to measure in the vicinity of the South Pole itself. This is overcome here by using data obtained by UK TechDemoSat-1. Data are processed to obtain the height of glacial ice across the Greenland and Antarctic ice sheets.
Marion Leduc-Leballeur, Ghislain Picard, Giovanni Macelloni, Arnaud Mialon, and Yann H. Kerr
The Cryosphere, 14, 539–548,Short summary
To study the coast and ice shelves affected by melt in Antarctica during the austral summer, we exploited the 1.4 GHz radiometric satellite observations. We showed that this frequency provides additional information on melt occurrence and on the location of the water in the snowpack compared to the 19 GHz observations. This opens an avenue for improving the melting season monitoring with a combination of both frequencies and exploring the possibility of deep-water detection in the snowpack.
Malcolm McMillan, Alan Muir, Andrew Shepherd, Roger Escolà, Mònica Roca, Jérémie Aublanc, Pierre Thibaut, Marco Restano, Américo Ambrozio, and Jérôme Benveniste
The Cryosphere, 13, 709–722,Short summary
Melting of the Greenland and Antarctic ice sheets is one of the main causes of current sea level rise. Understanding ice sheet change requires large-scale systematic satellite monitoring programmes. This study provides the first assessment of a new long-term source of measurements, from Sentinel-3 satellite altimetry. We estimate the accuracy of Sentinel-3 across Antarctica, show that the satellite can detect regions that are rapidly losing ice, and identify signs of subglacial lake activity.
Ian M. Howat, Claire Porter, Benjamin E. Smith, Myoung-Jong Noh, and Paul Morin
The Cryosphere, 13, 665–674,Short summary
The Reference Elevation Model of Antarctica (REMA) is the first continental-scale terrain map at less than 10 m resolution, and the first with a time stamp, enabling measurements of elevation change. REMA is constructed from over 300 000 individual stereoscopic elevation models (DEMs) extracted from submeter-resolution satellite imagery. REMA is vertically registered to satellite altimetry, resulting in errors of less than 1 m over most of its area and relative uncertainties of decimeters.
Kelly M. Brunt, Thomas A. Neumann, and Christopher F. Larsen
The Cryosphere, 13, 579–590,Short summary
This paper provides an assessment of new GPS elevation data collected near the South Pole, Antarctica, that will ultimately be used for ICESat-2 satellite elevation data validation. Further, using the new ground-based GPS data, this paper provides an assessment of airborne lidar elevation data collected between 2014 and 2017, which will also be used for ICESat-2 data validation.
Andrew G. Williamson, Alison F. Banwell, Ian C. Willis, and Neil S. Arnold
The Cryosphere, 12, 3045–3065,Short summary
A new approach is presented for automatically monitoring changes to area and volume of surface lakes on the Greenland Ice Sheet using Landsat 8 and Sentinel-2 satellite data. The dual-satellite record improves on previous work since it tracks changes to more lakes (including small ones), identifies more lake-drainage events, and has higher precision. The results also show that small lakes are important in ice-sheet hydrology as they route more surface run-off into the ice sheet than large lakes.
Anton Heister and Rolf Scheiber
The Cryosphere, 12, 2969–2979,Short summary
We provide a method based on Fourier analysis of coherent radio-echo sounding data for analyzing angular back-scattering characteristics of the ice sheet and bed. The characteristics can be used for the bed roughness estimation and detection of subglacial water. The method also offers improved estimation of the internal layers' tilt. The research is motivated by a need for a tool for training dictionaries for model-based tomographic focusing of multichannel coherent radio-echo sounders.
Jilu Li, Jose A. Vélez González, Carl Leuschen, Ayyangar Harish, Prasad Gogineni, Maurine Montagnat, Ilka Weikusat, Fernando Rodriguez-Morales, and John Paden
The Cryosphere, 12, 2689–2705,Short summary
Ice properties inferred from multi-polarization measurements can provide insight into ice strain, viscosity, and ice flow. The Center for Remote Sensing of Ice Sheets used a ground-based radar for multi-channel and multi-polarization measurements at the NEEM site. This paper describes the radar system, antenna configurations, data collection, and processing and analysis of this data set. Comparisons between the radar observations, simulations, and ice core fabric data are in very good agreement.
Fifi Ibrahime Adodo, Frédérique Remy, and Ghislain Picard
The Cryosphere, 12, 1767–1778,Short summary
In Antarctica, the seasonal cycle of the backscatter behaves differently at high and low frequencies, peaking in winter and in summer, respectively. At the intermediate frequency, some areas behave analogously to low frequency in terms of the seasonal cycle, but other areas behave analogously to high frequency. This calls into question the empirical relationships often used to correct elevation changes from radar penetration into the snowpack using backscatter.
Peter Friedl, Thorsten C. Seehaus, Anja Wendt, Matthias H. Braun, and Kathrin Höppner
The Cryosphere, 12, 1347–1365,Short summary
Fleming Glacier is the biggest tributary glacier of the former Wordie Ice Shelf. Radar satellite data and airborne ice elevation measurements show that the glacier accelerated by ~27 % between 2008–2011 and that ice thinning increased by ~70 %. This was likely a response to a two-phase ungrounding of the glacier tongue between 2008 and 2011, which was mainly triggered by increased basal melt during two strong upwelling events of warm circumpolar deep water.
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Beck, R., Zhan, S., Liu, H., Tong, S., Yang, B., Xu, M., Ye, Z., Huang, Y., Shu, S., Wu, Q., Wang, S., Berling, K., Murray, A., Emery, E., Reif, M., Harwood, J., Young, J., Nietch, C., Macke, D., Martin, M., Stillings, G., Stump, R., and Su, H.: Comparison of satellite reflectance algorithms for estimating chlorophyll a in a temperate reservoir using coincident hyperspectral aircraft imagery and dense coincident surface observations, Remote Sens. Environ., 178(Supplement C), 15–30, 2016.
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Casey, K. A., Polashenski, C. M., Chen, J., and Tedesco, M.: Impact of MODIS sensor calibration updates on Greenland Ice Sheet surface reflectance and albedo trends, The Cryosphere, 11, 1781–1795, https://doi.org/10.5194/tc-11-1781-2017, 2017.
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Glacial algal blooms play a significant role in darkening the Greenland Ice Sheet during summertime. The dark pigments generated by glacial algae could substantially reduce the bare ice albedo and thereby enhance surface melt. We used satellite data to map the spatial distribution of glacial algae and characterized the seasonal growth pattern and interannual trends of glacial algae in southwestern Greenland. Our study is important for bridging microbial activities with ice sheet mass balance.
Glacial algal blooms play a significant role in darkening the Greenland Ice Sheet during...