Subglacial topography and thickness of ice caps on the Argentine Islands

2019 ◽  
Vol 31 (6) ◽  
pp. 332-344 ◽  
Author(s):  
Jānis Karušs ◽  
Kristaps Lamsters ◽  
Anatolii Chernov ◽  
Māris Krievāns ◽  
Jurijs Ješkins
Keyword(s):  
Land Surface ◽  
Geological Structure ◽  
Aerial Images ◽  
Ice Thickness ◽  
Ice Caps ◽  
The North ◽  
Prevailing Wind Direction ◽  
Aerial Vehicle ◽  
Subglacial Topography ◽  
Ground Penetrating

AbstractThis study presents the first subglacial topography and ice thickness models of the largest ice caps of the Argentine Islands, Wilhelm Archipelago, West Antarctica. During this study, ground-penetrating radar was used to map the thickness and inner structure of the ice caps. Digital surface models of all studied islands were created from aerial images obtained with a small-sized unmanned aerial vehicle and used for the construction of subglacial topography models. Ice caps of the Argentine Islands cover ~50% of the land surface of the islands on average. The maximum thickness of only two islands (Galindez and Skua) exceeds 30 m, while the average thickness of all islands is only ~5 m. The maximum ice thickness reaches 35.3 m on Galindez Island. The ice thickness and glacier distribution are mainly governed by prevailing wind direction from the north. This has created the prominent narrow ice ridges on Uruguay and Irizar islands, which are not supported by topographic obstacles, as well as the elongated shape of other ice caps. The subglacial topography of the ice caps is undulated and mainly dependent on the geological structure and composition of magmatic rocks.

scholarly journals Neural Networks Applied to Estimating Subglacial Topography and Glacier Volume

2009 ◽  
Vol 22 (8) ◽  
pp. 2146-2160 ◽  
Author(s):  
Garry K. C. Clarke ◽  
Etienne Berthier ◽  
Christian G. Schoof ◽  
Alexander H. Jarosch
Keyword(s):  
Neural Network ◽  
Regional Scale ◽  
Ice Thickness ◽  
Ice Dynamics ◽  
Ice Caps ◽  
Mountain Glaciers ◽  
The Neural Network ◽  
Glacier Ice ◽  
Subglacial Topography ◽  
Artificial Neural Network Ann

Abstract To predict the rate and consequences of shrinkage of the earth’s mountain glaciers and ice caps, it is necessary to have improved regional-scale models of mountain glaciation and better knowledge of the subglacial topography upon which these models must operate. The problem of estimating glacier ice thickness is addressed by developing an artificial neural network (ANN) approach that uses calculations performed on a digital elevation model (DEM) and on a mask of the present-day ice cover. Because suitable data from real glaciers are lacking, the ANN is trained by substituting the known topography of ice-denuded regions adjacent to the ice-covered regions of interest, and this known topography is hidden by imagining it to be ice-covered. For this training it is assumed that the topography is flooded to various levels by horizontal lake-like glaciers. The validity of this assumption and the estimation skill of the trained ANN is tested by predicting ice thickness for four 50 km × 50 km regions that are currently ice free but that have been partially glaciated using a numerical ice dynamics model. In this manner, predictions of ice thickness based on the neural network can be compared to the modeled ice thickness and the performance of the neural network can be evaluated and improved. From the results, thus far, it is found that ANN depth estimates can yield plausible subglacial topography with a representative rms elevation error of ±70 m and remarkably good estimates of ice volume.

scholarly journals First ice thickness measurements in Tierra del Fuego at Glacier Schiaparelli, Chile

2020 ◽  
Author(s):  
Guisella Gacitúa ◽  
Christoph Schneider ◽  
Jorge Arigony ◽  
Inti González ◽  
Ricardo Jaña ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Tierra Del Fuego ◽  
Ice Thickness ◽  
In Situ Observation ◽  
Fundamental Parameters ◽  
The North ◽  
Transect Line ◽  
Northern Side ◽  
Ground Penetrating ◽  
Thickness Measurements

Abstract. Cordillera Darwin in Tierra del Fuego (Chile) remains one of the least studied glaciated regions in the world. However, this region being one of very few terrestrial sites at this latitude in the Southern Hemisphere has the potential to provide key information on the effect of climate variability and climate change on the cryosphere at sub-polar mid-latitudes of the Southern Hemisphere. Glacier Schiaparelli is located at the northern side of the Cordillera Darwin draining the north side of Monte Sarmiento (2187 m asl). Despite being one of the largest glaciers in the Cordillera Darwin no previous in situ observation of its ice thickness had been made neither at this glacier nor at any other location in the Cordillera Darwin. Ice thickness is one of the fundamental parameters to understand glaciers dynamics, constrain ice dynamical modelling and predict glacier evolution. In April 2016 we performed the first successful ice thickness measurements using terrestrial ground- penetrating radar in the ablation area of Glacier Schiaparelli (Gacitúa et al., 2020), https://doi.org/10.1594/PANGAEA.919331. The measurements were made along a transect line perpendicular to the ice flow. Results show a valley shaped bedrock with a maximum ice thickness of 324 m within a distinct glacier trough. The bedrock is located below current sea level for 51 % of the transect measurements with a minimum of −158 m which illustrates that the local topography is subject to considerable glacier-related over-deepening.

scholarly journals Pervasive cold ice within a temperate glacier – implications for glacier thermal regimes, sediment transport and foreland geomorphology

2019 ◽  
Vol 13 (3) ◽  
pp. 827-843 ◽  
Author(s):  
Benedict T. I. Reinardy ◽  
Adam D. Booth ◽  
Anna L. C. Hughes ◽  
Clare M. Boston ◽  
Henning Åkesson ◽  
...  
Keyword(s):  
Climate Warming ◽  
Ground Penetrating Radar ◽  
Radar Data ◽  
Ice Thickness ◽  
Systematic Mapping ◽  
Ablation Area ◽  
Seasonal Snow ◽  
Thermal Regimes ◽  
Subglacial Topography ◽  
Ground Penetrating

Abstract. This study suggests that cold-ice processes may be more widespread than previously assumed, even within temperate glacial systems. We present the first systematic mapping of cold ice at the snout of the temperate glacier Midtdalsbreen, an outlet of the Hardangerjøkulen icefield (Norway), from 43 line kilometres of ground-penetrating radar data. Results show a 40 m wide cold-ice zone within the majority of the glacier snout, where ice thickness is <10 m. We interpret ice to be cold-based across this zone, consistent with basal freeze-on processes involved in the deposition of moraines. We also find at least two zones of cold ice up to 15 m thick within the ablation area, occasionally extending to the glacier bed. There are two further zones of cold ice up to 30 m thick in the accumulation area, also extending to the glacier bed. Cold-ice zones in the ablation area tend to correspond to areas of the glacier that are covered by late-lying seasonal snow patches that reoccur over multiple years. Subglacial topography and the location of the freezing isotherm within the glacier and underlying subglacial strata likely influence the transport and supply of supraglacial debris and formation of controlled moraines. The wider implication of this study is the possibility that, with continued climate warming, temperate environments with primarily temperate glaciers could become polythermal in forthcoming decades with (i) persisting thinning and (ii) retreat to higher altitudes where subglacial permafrost could be and/or become more widespread. Adversely, the number and size of late-lying snow patches in ablation areas may decrease and thereby reduce the extent of cold ice, reinforcing the postulated change in the thermal regime.

scholarly journals First ice thickness measurements in Tierra del Fuego at Schiaparelli Glacier, Chile

2021 ◽  
Vol 13 (2) ◽  
pp. 231-236
Author(s):  
Guisella Gacitúa ◽  
Christoph Schneider ◽  
Jorge Arigony ◽  
Inti González ◽  
Ricardo Jaña ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Tierra Del Fuego ◽  
Ice Thickness ◽  
In Situ Observation ◽  
Fundamental Parameters ◽  
The North ◽  
Transect Line ◽  
Northern Side ◽  
Ground Penetrating ◽  
Thickness Measurements

Abstract. Cordillera Darwin in Tierra del Fuego (Chile) remains one of the least studied glaciated regions in the world. However, this region being one of very few terrestrial sites at this latitude in the Southern Hemisphere has the potential to provide key information on the effect of climate variability and climate change on the cryosphere at sub-polar mid-latitudes of the Southern Hemisphere. Schiaparelli Glacier is located at the northern side of the Cordillera Darwin draining the north side of Monte Sarmiento (2187 m a.s.l.). Despite being one of the largest glaciers in the Cordillera Darwin, no previous in situ observation of its ice thickness had been made either at this glacier or at any other location in the Cordillera Darwin. Ice thickness is one of the fundamental parameters to understand glacier dynamics, constrain ice dynamical modelling, and predict glacier evolution. In April 2016 we performed the first successful ice thickness measurements using terrestrial ground-penetrating radar in the ablation area of Schiaparelli Glacier (Gacitúa et al., 2020, https://doi.org/10.1594/PANGAEA.919331). The measurements were made along a transect line perpendicular to the ice flow. Results show a valley-shaped bedrock with a maximum ice thickness of 324 m within a distinct glacier trough. The bedrock is located below current sea level for 51 % of the transect measurements with a minimum of −158 m, which illustrates that the local topography is subject to considerable glacier-related over-deepening.

scholarly journals The feasibility of imaging subglacial hydrology beneath ice streams with ground-based electromagnetics

2017 ◽  
Vol 63 (241) ◽  
pp. 755-771 ◽  
Author(s):  
KERRY KEY ◽  
MATTHEW R. SIEGFRIED
Keyword(s):  
Geophysical Methods ◽  
Ice Sheet ◽  
Geological Structure ◽  
Ice Thickness ◽  
Ice Streams ◽  
Water Conductivity ◽  
Model Studies ◽  
Seismic Surveying ◽  
Ice Sheet Dynamics ◽  
Ground Penetrating

ABSTRACTSubglacial hydrologic systems in Antarctica and Greenland play a fundamental role in ice-sheet dynamics, yet critical aspects of these systems remain poorly understood due to a lack of observations. Ground-based electromagnetic (EM) geophysical methods are established for mapping groundwater in many environments, but have never been applied to imaging lakes beneath ice sheets. Here, we study the feasibility of passive- and active-source EM imaging for quantifying the nature of subglacial water systems beneath ice streams, with an emphasis on the interfaces between ice and basal meltwater, as well as deeper groundwater in the underlying sediments. We describe a suite of model studies that exam the data sensitivity as a function of ice thickness, water conductivity and hydrologic system geometry for models representative of a subglacial lake and a grounding zone estuary. We show that EM data are directly sensitive to groundwater and can image its lateral and depth extent. By combining the conductivity obtained from EM data with ice thickness and geological structure from conventional geophysical techniques, such as ground-penetrating radar and active seismic surveying, EM data have the potential to provide new insights on the interaction between ice, rock and water at critical ice-sheet boundaries.

scholarly journals Complex of Geophysical Studies of the Seyakha Catastrophic Gas Blowout Crater on the Yamal Peninsula, Russian Arctic

Geosciences ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 215
Author(s):  
Vasily Bogoyavlensky ◽  
Igor Bogoyavlensky ◽  
Roman Nikonov ◽  
Aleksei Kishankov
Keyword(s):  
Yamal Peninsula ◽  
Near Surface ◽  
Biogenic Methane ◽  
The North ◽  
Digital Elevation ◽  
Show Evidence ◽  
Aerial Vehicle ◽  
Elevation Model ◽  
Ground Penetrating ◽  
The Yamal Peninsula

This article describes the main results of two Arctic expeditions in 2017–2018 to study the Seyakha Crater in the north of Western Siberia, Yamal Peninsula. It was formed on a place of a pingo-like feature (PLF) by huge blowout, self-ignition, and explosion of gas on 28 June 2017. In 2018, for the first time, the integration of geophysical studies on the Yamal Peninsula revealed in detail an Arctic gas-blowout crater within a river channel and adjacent land with permafrost. On the basis of unmanned aerial vehicle photography, echo sounding, and ground penetrating radar survey data processing, a 3D digital elevation model (DEM) of the crater and the structure of near-surface deposits was created. A previously unknown uplift inside the permafrost layers, probably connected with the processes of gas chamber formation, was revealed. A long period of continuous gas emission (mainly, biogenic methane) from the Seyakha C11 Crater (2017–2019) and other existing data show evidence for a gas-dynamic mechanism of the PLF growth and a volcanic type of eruption.

The New Swedish Cyprus Expedition 2010. Excavations at Dromolaxia Vizatzia/Hala Sultan Tekke. Preliminary results

2011 ◽  
Vol 4 ◽  
pp. 69-98 ◽  
Author(s):  
Peter M. Fischer ◽  
Patrik Klingborg ◽  
Fanny Kärfve ◽  
Fredrika Kärfve ◽  
C. Hagberg ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Main Task ◽  
Phase 2 ◽  
The North ◽  
12Th Century ◽  
Area 6 ◽  
Recent Phase ◽  
The Rich ◽  
Ground Penetrating

Determination of the complete occupational sequence of the site, including investigation of pre-12th century levels which were thoroughly studied by P. Åström since the 1970s, is the main task of the planned project. During the course of the expedition (NSCE11) in spring 2010 a ground-penetrating radar survey (GPR) was carried out at Dromolaxia Vizatzia/Hala Sultan Tekke in Area 6, leading to the discovery of a large Late Cypriote complex. The compound is bordered to the north by a substantial wall, against which nine rooms (so far) could be exposed. Two occupational phases have been verified but there are indications of a third. The suggested functions of the various structures of the most recent phase are: living, working, storage and administration spaces. The rich find contexts point to the production of textiles and metal objects, and the locally produced pottery is generally of a high quality. There are also many imports, mainly from the Mycenaean sphere of culture. The locally produced vessels from Phase 2 include the “Creature krater” which is a masterpiece of a high artistic standard. Another piece of elevated artistry is the piece of a “Warrior vase”.

scholarly journals Ice thickness distribution of all Swiss glaciers based on extended ground-penetrating radar data and glaciological modeling

2021 ◽  
pp. 1-19
Author(s):  
Melchior Grab ◽  
Enrico Mattea ◽  
Andreas Bauder ◽  
Matthias Huss ◽  
Lasse Rabenstein ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Thickness Distribution ◽  
Radar Data ◽  
Tourism Industry ◽  
Swiss Alps ◽  
Ice Thickness ◽  
Hazard Management ◽  
Bed Topography ◽  
Ice Volume ◽  
Ground Penetrating

Abstract Accurate knowledge of the ice thickness distribution and glacier bed topography is essential for predicting dynamic glacier changes and the future developments of downstream hydrology, which are impacting the energy sector, tourism industry and natural hazard management. Using AIR-ETH, a new helicopter-borne ground-penetrating radar (GPR) platform, we measured the ice thickness of all large and most medium-sized glaciers in the Swiss Alps during the years 2016–20. Most of these had either never or only partially been surveyed before. With this new dataset, 251 glaciers – making up 81% of the glacierized area – are now covered by GPR surveys. For obtaining a comprehensive estimate of the overall glacier ice volume, ice thickness distribution and glacier bed topography, we combined this large amount of data with two independent modeling algorithms. This resulted in new maps of the glacier bed topography with unprecedented accuracy. The total glacier volume in the Swiss Alps was determined to be 58.7 ± 2.5 km3 in the year 2016. By projecting these results based on mass-balance data, we estimated a total ice volume of 52.9 ± 2.7 km3 for the year 2020. Data and modeling results are accessible in the form of the SwissGlacierThickness-R2020 data package.

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