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- Landsat, MODIS, and VIIRS snow cover mapping algorithm performance as
validated by airborne lidar datasets
Abstract: Landsat, MODIS, and VIIRS snow cover mapping algorithm performance as validated by airborne lidar datasets
Timbo Stillinger, Karl Rittger, Mark S. Raleigh, Alex Michell, Robert E. Davis, and Edward H. Bair
The Cryosphere Discuss., https//doi.org/10.5194/tc-2022-159,2022
Preprint under review for TC (discussion: open, 0 comments)
Understanding global snow cover is critical for comprehending climate change and its impacts on the lives of billions of people. Satellites are the best way to monitor global snow cover, yet snow varies at a finer spatial resolution than most satellite images. We assessed sub pixel snow mapping methods across a spectrum of conditions using airborne lidar. Spectral unmixing methods outperformed older operational methods and are ready to to advance snow cover mapping at the global scale.
PubDate: Mon, 15 Aug 2022 23:27:31 +020
DOI: 10.5194/tc-2022-1592022
- TermPicks: a century of Greenland glacier terminus data for use in
scientific and machine learning applications
Abstract: TermPicks: a century of Greenland glacier terminus data for use in scientific and machine learning applications
Sophie Goliber, Taryn Black, Ginny Catania, James M. Lea, Helene Olsen, Daniel Cheng, Suzanne Bevan, Anders Bjørk, Charlie Bunce, Stephen Brough, J. Rachel Carr, Tom Cowton, Alex Gardner, Dominik Fahrner, Emily Hill, Ian Joughin, Niels J. Korsgaard, Adrian Luckman, Twila Moon, Tavi Murray, Andrew Sole, Michael Wood, and Enze Zhang
The Cryosphere, 16, 3215–3233, https://doi.org/10.5194/tc-16-3215-2022, 2022
Terminus traces have been used to understand how Greenland's glaciers have changed over time; however, manual digitization is time-intensive, and a lack of coordination leads to duplication of efforts. We have compiled a dataset of over 39 000 terminus traces for 278 glaciers for scientific and machine learning applications. We also provide an overview of an updated version of the Google Earth Engine Digitization Tool (GEEDiT), which has been developed specifically for the Greenland Ice Sheet.
PubDate: Fri, 12 Aug 2022 23:27:31 +020
DOI: 10.5194/tc-16-3215-2022 2022
- Improving model-satellite comparisons of sea ice melt onset with a
satellite simulator
Abstract: Improving model-satellite comparisons of sea ice melt onset with a satellite simulator
Abigail Smith, Alexandra Jahn, Clara Burgard, and Dirk Notz
The Cryosphere, 16, 3235–3248, https://doi.org/10.5194/tc-16-3235-2022, 2022
The timing of Arctic sea ice melt each year is an important metric for assessing how sea ice in climate models compares to satellite observations. Here, we utilize a new tool for creating more direct comparisons between climate model projections and satellite observations of Arctic sea ice, such that the melt onset dates are defined the same way. This tool allows us to identify climate model biases more clearly and gain more information about what the satellites are observing.
PubDate: Fri, 12 Aug 2022 23:27:31 +020
DOI: 10.5194/tc-16-3235-2022 2022
- Effects of extreme melt events on ice flow and sea level rise of the
Greenland Ice Sheet
Abstract: Effects of extreme melt events on ice flow and sea level rise of the Greenland Ice Sheet
Johanna Beckmann and Ricarda Winkelmann
The Cryosphere Discuss., https//doi.org/10.5194/tc-2022-145,2022
Preprint under review for TC (discussion: open, 0 comments)
Over the past decade, Greenland has experienced several extreme melt events. With progressing climate change, such extreme melt events can be expected to occur more frequently and potentially become more severe and persistent. Strong melt events may considerably contribute to Greenland's mass loss, that in turn strongly determines future sea level rise. How important these extreme melt events could be in the future is assessed in this study for the first time.
PubDate: Thu, 11 Aug 2022 23:27:31 +020
DOI: 10.5194/tc-2022-1452022
- Comparison of manual snow water equivalent (SWE) measurements: seeking the
reference for a true SWE value in a boreal biome
Abstract: Comparison of manual snow water equivalent (SWE) measurements: seeking the reference for a true SWE value in a boreal biome
Maxime Beaudoin-Galaise and Sylvain Jutras
The Cryosphere, 16, 3199–3214, https://doi.org/10.5194/tc-16-3199-2022, 2022
Our study presents an analysis of the uncertainty and measurement error of manual measurement methods of the snow water equivalent (SWE). Snow pit and snow sampler measurements were taken during five consecutive winters. Our results show that, although the snow pit is considered a SWE reference in the literature, it is a method with higher uncertainty and measurement error than large diameter samplers, considered according to our results as the most appropriate reference in a boreal biome.
PubDate: Wed, 10 Aug 2022 22:30:50 +020
DOI: 10.5194/tc-16-3199-2022 2022
- Seasonal variability in Antarctic ice shelf velocities forced by sea
surface height variations
Abstract: Seasonal variability in Antarctic ice shelf velocities forced by sea surface height variations
Cyrille Mosbeux, Laurie Padman, Emilie Klein, Peter B. Bromirski, and Helen A. Fricker
The Cryosphere Discuss., https//doi.org/10.5194/tc-2022-153,2022
Preprint under review for TC (discussion: open, 0 comments)
Antarctica’s ice shelves (the floating extension of the ice sheet) help regulate ice flow. As ice shelves thin or lose contact with the bedrock, the upstream ice tends to accelerate, resulting in increased mass loss. Here, we use an ice sheet model to simulate the effect of seasonal sea surface height variations and see if we can reproduce observed seasonal variability of ice velocity on the ice shelf. When correctly parametrized, the model fits well the observations.
PubDate: Tue, 09 Aug 2022 22:30:50 +020
DOI: 10.5194/tc-2022-1532022
- Ongoing grounding line retreat and fracturing initiated at the Petermann
Glacier ice shelf, Greenland, after 2016
Abstract: Ongoing grounding line retreat and fracturing initiated at the Petermann Glacier ice shelf, Greenland, after 2016
Romain Millan, Jeremie Mouginot, Anna Derkacheva, Eric Rignot, Pietro Milillo, Enrico Ciraci, Luigi Dini, and Anders Bjørk
The Cryosphere, 16, 3021–3031, https://doi.org/10.5194/tc-16-3021-2022, 2022
We detect for the first time a dramatic retreat of the grounding line of Petermann Glacier, a major glacier of the Greenland Ice Sheet. Using satellite data, we also observe a speedup of the glacier and a fracturing of the ice shelf. This sequence of events is coherent with ocean warming in this region and suggests that Petermann Glacier has initiated a phase of destabilization, which is of prime importance for the stability and future contribution of the Greenland Ice Sheet to sea level rise.
PubDate: Mon, 08 Aug 2022 22:30:50 +020
DOI: 10.5194/tc-16-3021-2022 2022
- Exploring ice sheet model sensitivity to ocean thermal forcing using the
Community Ice Sheet Model (CISM)
Abstract: Exploring ice sheet model sensitivity to ocean thermal forcing using the Community Ice Sheet Model (CISM)
Mira Berdahl, Gunter Leguy, William H. Lipscomb, Nathan M. Urban, and Matthew J. Hoffman
The Cryosphere Discuss., https//doi.org/10.5194/tc-2022-156,2022
Preprint under review for TC (discussion: open, 0 comments)
Contributions to future sea level from the Antarctic ice sheet remain poorly constrained. One reason is that ice sheet model initialization methods can have significant impacts on how the ice sheet responds to future forcings. We investigate the impacts of two key parameters that are used during model initialization. We find that these parameter choices alone can impact multi-century sea level rise by up to 2 m, emphasizing the need to carefully consider these choices for level rise predictions.
PubDate: Mon, 08 Aug 2022 22:30:50 +020
DOI: 10.5194/tc-2022-1562022
- Thickness of multi-year sea ice on the northern Canadian polar shelf: a
second look after 40 years
Abstract: Thickness of multi-year sea ice on the northern Canadian polar shelf: a second look after 40 years
Humfrey Melling
The Cryosphere, 16, 3181–3197, https://doi.org/10.5194/tc-16-3181-2022, 2022
The Canadian polar shelf has the world’s thickest old sea ice. Its islands impede ice drift to warmer seas. The first year of data from up-looking sonar viewing this shelf’s ice reveal that thick (> 3 m) old ice remains plentiful here, in contrast to its growing scarcity elsewhere. Arctic circulation continues to pack ice against the islands and during storms to create by ridging the very thick ice found here. This study reveals the importance of ridging to the mass balance of Arctic sea ice.
PubDate: Fri, 05 Aug 2022 22:30:50 +020
DOI: 10.5194/tc-16-3181-2022 2022
- Multi-annual temperature evolution and implications for cave ice
development in a sag-type ice cave in the Austrian Alps
Abstract: Multi-annual temperature evolution and implications for cave ice development in a sag-type ice cave in the Austrian Alps
Maria Wind, Friedrich Obleitner, Tanguy Racine, and Christoph Spötl
The Cryosphere, 16, 3163–3179, https://doi.org/10.5194/tc-16-3163-2022, 2022
We present a thorough analysis of the thermal conditions of a sag-type ice cave in the Austrian Alps using temperature measurements for the period 2008–2021. Apart from a long-term increasing temperature trend in all parts of the cave, we find strong interannual and spatial variations as well as a characteristic seasonal pattern. Increasing temperatures further led to a drastic decrease in cave ice. A first attempt to model ablation based on temperature shows promising results.
PubDate: Fri, 05 Aug 2022 22:30:50 +020
DOI: 10.5194/tc-16-3163-2022 2022
- Surge dynamics of Shisper Glacier revealed by time-series correlation of
optical satellite images and their utility to substantiate a generalized
sliding law
Abstract: Surge dynamics of Shisper Glacier revealed by time-series correlation of optical satellite images and their utility to substantiate a generalized sliding law
Flavien Beaud, Saif Aati, Ian Delaney, Surendra Adhikari, and Jean-Philippe Avouac
The Cryosphere, 16, 3123–3148, https://doi.org/10.5194/tc-16-3123-2022, 2022
Understanding sliding at the bed of glaciers is essential to understand the future of sea-level rise and glacier-related hazards. Yet there is currently no universal law to describe this mechanism. We propose a universal glacier sliding law and a method to qualitatively constrain it. We use satellite remote sensing to create velocity maps over 6 years at Shisper Glacier, Pakistan, including its recent surge, and show that the observations corroborate the generalized theory.
PubDate: Wed, 03 Aug 2022 00:03:46 +020
DOI: 10.5194/tc-16-3123-2022 2022
- A data exploration tool for averaging and accessing large data sets of
snow stratigraphy profiles useful for avalanche forecasting
Abstract: A data exploration tool for averaging and accessing large data sets of snow stratigraphy profiles useful for avalanche forecasting
Florian Herla, Pascal Haegeli, and Patrick Mair
The Cryosphere, 16, 3149–3162, https://doi.org/10.5194/tc-16-3149-2022, 2022
We present an averaging algorithm for multidimensional snow stratigraphy profiles that elicits the predominant snow layering among large numbers of profiles and allows for compiling of informative summary statistics and distributions of snowpack layer properties. This creates new opportunities for presenting and analyzing operational snowpack simulations in support of avalanche forecasting and may inspire new ways of processing profiles and time series in other geophysical contexts.
PubDate: Wed, 03 Aug 2022 00:03:46 +020
DOI: 10.5194/tc-16-3149-2022 2022
- Modelling glacier mass balance and climate sensitivity in the context of
sparse observations: application to Saskatchewan Glacier, western Canada
Abstract: Modelling glacier mass balance and climate sensitivity in the context of sparse observations: application to Saskatchewan Glacier, western Canada
Christophe Kinnard, Olivier Larouche, Michael N. Demuth, and Brian Menounos
The Cryosphere, 16, 3071–3099, https://doi.org/10.5194/tc-16-3071-2022, 2022
This study implements a physically based, distributed glacier mass balance model in a context of sparse direct observations. Carefully constraining model parameters with ancillary data allowed for accurately reconstructing the mass balance of Saskatchewan Glacier over a 37-year period. We show that the mass balance sensitivity to warming is dominated by increased melting and that changes in glacier albedo and air humidity are the leading causes of increased glacier melt under warming scenarios.
PubDate: Tue, 02 Aug 2022 00:03:46 +020
DOI: 10.5194/tc-16-3071-2022 2022
- Evaporation over a glacial lake in Antarctica
Abstract: Evaporation over a glacial lake in Antarctica
Elena Shevnina, Miguel Potes, Timo Vihma, Tuomas Naakka, Pankaj Ramji Dhote, and Praveen Kumar Thakur
The Cryosphere, 16, 3101–3121, https://doi.org/10.5194/tc-16-3101-2022, 2022
The evaporation over an ice-free glacial lake was measured in January 2018, and the uncertainties inherent to five indirect methods were quantified. Results show that in summer up to 5 mm of water evaporated daily from the surface of the lake located in Antarctica. The indirect methods underestimated the evaporation over the lake's surface by up to 72 %. The results are important for estimating the evaporation over polar regions where a growing number of glacial lakes have recently been evident.
PubDate: Tue, 02 Aug 2022 00:03:46 +020
DOI: 10.5194/tc-16-3101-2022 2022
- Offset of MODIS land surface temperatures from in situ air temperatures in
the upper Kaskawulsh Glacier region (St. Elias Mountains) indicates
near-surface temperature inversions
Abstract: Offset of MODIS land surface temperatures from in situ air temperatures in the upper Kaskawulsh Glacier region (St. Elias Mountains) indicates near-surface temperature inversions
Ingalise Kindstedt, Kristin M. Schild, Dominic Winski, Karl Kreutz, Luke Copland, Seth Campbell, and Erin McConnell
The Cryosphere, 16, 3051–3070, https://doi.org/10.5194/tc-16-3051-2022, 2022
We show that neither the large spatial footprint of the MODIS sensor nor poorly constrained snow emissivity values explain the observed cold offset in MODIS land surface temperatures (LSTs) in the St. Elias. Instead, the offset is most prominent under conditions associated with near-surface temperature inversions. This work represents an advance in the application of MODIS LSTs to glaciated alpine regions, where we often depend solely on remote sensing products for temperature information.
PubDate: Tue, 02 Aug 2022 00:03:46 +020
DOI: 10.5194/tc-16-3051-2022 2022
- The surface energy balance during foehn events at Joyce Glacier, McMurdo
Dry Valleys, Antarctica
Abstract: The surface energy balance during foehn events at Joyce Glacier, McMurdo Dry Valleys, Antarctica
Marte G. Hofsteenge, Nicolas J. Cullen, Carleen H. Reijmer, Michiel van den Broeke, Marwan Katurji, and John F. Orwin
The Cryosphere Discuss., https//doi.org/10.5194/tc-2022-102,2022
Preprint under review for TC (discussion: open, 0 comments)
Foehn winds are warm and dry downslope winds that occur in mountainous areas. In the McMurdo Dry Valleys, foehn winds impact meltwater production of the glaciers, which in turn can have big implications for the fragile ecosystem that is hosted here. With observations and model output we show that foehn winds increase the air and glacier surface temperatures, thereby increasing the occurrence and rates of melt. Foehn winds also impact the atmospheric stability and wind regime of the glaciers.
PubDate: Tue, 02 Aug 2022 00:03:46 +020
DOI: 10.5194/tc-2022-1022022
- GBaTSv2: a revised synthesis of the likely basal thermal state of the
Greenland Ice Sheet
Abstract: GBaTSv2: a revised synthesis of the likely basal thermal state of the Greenland Ice Sheet
Joseph A. MacGregor, Winnie Chu, William T. Colgan, Mark A. Fahnestock, Denis Felikson, Nanna B. Karlsson, Sophie M. J. Nowicki, and Michael Studinger
The Cryosphere, 16, 3033–3049, https://doi.org/10.5194/tc-16-3033-2022, 2022
Where the bottom of the Greenland Ice Sheet is frozen and where it is thawed is not well known, yet knowing this state is increasingly important to interpret modern changes in ice flow there. We produced a second synthesis of knowledge of the basal thermal state of the ice sheet using airborne and satellite observations and numerical models. About one-third of the ice sheet’s bed is likely thawed; two-fifths is likely frozen; and the remainder is too uncertain to specify.
PubDate: Mon, 01 Aug 2022 00:03:46 +020
DOI: 10.5194/tc-16-3033-2022 2022
- Changes in the annual sea ice freeze-thaw cycle in the Arctic Ocean from
2001 to 2018
Abstract: Changes in the annual sea ice freeze-thaw cycle in the Arctic Ocean from 2001 to 2018
Long Lin, Ruibo Lei, Mario Hoppmann, Donald K. Perovich, and Hailun He
The Cryosphere Discuss., https//doi.org/10.5194/tc-2022-137,2022
Preprint under review for TC (discussion: open, 0 comments)
Ice mass balance observations indicated that average basal melt onset were comparable in the Central Arctic ocean, and approximately 17 days earlier than surface in the Beaufort Gyre. While average onset of basal growth were almost three months lagging behind surface for the entire Arctic Ocean. In the Beaufort Gyre, basal melt onset derived from both drifting buoy observations and fixed point observations exhibits an earlier trend, which can be ascribe to the earlier warming of surface ocean.
PubDate: Fri, 29 Jul 2022 00:20:05 +020
DOI: 10.5194/tc-2022-1372022
- Timescales of outlet-glacier flow with negligible basal friction: Theory,
observations and modeling
Abstract: Timescales of outlet-glacier flow with negligible basal friction: Theory, observations and modeling
Johannes Feldmann and Anders Levermann
The Cryosphere Discuss., https//doi.org/10.5194/tc-2022-141,2022
Preprint under review for TC (discussion: open, 0 comments)
Here we present a scaling relation that allows the comparison of the timescales of glaciers with geometric similarity. According to the relation, thicker and wider glaciers on a steeper bed slope have a much faster timescale than shallower, narrower glaciers on a flatter bed slope. The relation is supported by observations and simplified numerical simulations. We combine the scaling relation with a statistical analysis of the topography of 13 instability-prone Antarctic outlet glaciers.
PubDate: Fri, 29 Jul 2022 00:20:05 +020
DOI: 10.5194/tc-2022-1412022
- Wind Transport of Snow Impacts Ka- and Ku-band Radar Signatures on Arctic
Sea Ice
Abstract: Wind Transport of Snow Impacts Ka- and Ku-band Radar Signatures on Arctic Sea Ice
Vishnu Nandan, Rosemary Willatt, Robbie Mallett, Julienne Stroeve, Torsten Geldsetzer, Randall Scharien, Rasmus Tonboe, Jack Landy, David Clemens-Sewall, Arttu Jutila, David N. Wagner, Daniela Krampe, Marcus Huntemann, John Yackel, Mallik Mahmud, David Jensen, Thomas Newman, Stefan Hendricks, Gunnar Spreen, Amy Macfarlane, Martin Schneebeli, James Mead, Robert Ricker, Michael Gallagher, Claude Duguay, Ian Raphael, Chris Polashenski, Michel Tsamados, Ilkka Matero, and Mario Hoppman
The Cryosphere Discuss., https//doi.org/10.5194/tc-2022-116,2022
Preprint under review for TC (discussion: open, 0 comments)
We show that, wind blows and redistributes snow on sea ice, and Ka- and Ku-band radar signatures detect both newly deposited and buried snow layers that can critically affect snow depth measurements on ice. Radar measurements, meteorological and snow physical data were collected during the MOSAiC Expedition. With frequent occurrence of storms in the Arctic, our results provide baseline information that are vitally important for accurately calculating snow depth on sea ice from satellite radars.
PubDate: Fri, 29 Jul 2022 00:20:05 +020
DOI: 10.5194/tc-2022-1162022
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