scholarly journals The bedrock topography of Gries- and Findelengletscher

2018 ◽  
Vol 73 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Nadine Feiger ◽  
Matthias Huss ◽  
Silvan Leinss ◽  
Leo Sold ◽  
Daniel Farinotti
Keyword(s):  
Spatial Interpolation ◽  
Thickness Distribution ◽  
Estimation Method ◽  
Ice Thickness ◽  
Glacier Surface ◽  
Ice Flow ◽  
Bedrock Topography ◽  
Abstract Knowledge ◽  
Ground Penetrating ◽  
Item Item

Abstract. Knowledge of the ice thickness distribution of glaciers is important for glaciological and hydrological applications. In this contribution, we present two updated bedrock topographies and ice thickness distributions for Gries- and Findelengletscher, Switzerland. The results are based on ground-penetrating radar (GPR) measurements collected in spring 2015 and already-existing data. The GPR data are analysed using ReflexW software and interpolated by using the ice thickness estimation method (ITEM). ITEM calculates the thickness distribution by using principles of ice flow dynamics and characteristics of the glacier surface. We show that using such a technique has a significance advantage compared to a direct interpolation of the measurements, especially for glacier areas that are sparsely covered by GPR data. The uncertainties deriving from both the interpretation of the GPR signal and the spatial interpolation through ITEM are quantified separately, showing that, in our case, GPR signal interpretation is a major source of uncertainty. The results show a total glacier volume of 0.28±0.06 and 1.00±0.34 km3 for Gries- and Findelengletscher, respectively, with corresponding average ice thicknesses of 56.8±12.7 and 56.3±19.6 m.

scholarly journals The ice thickness distribution of Flask Glacier, Antarctic Peninsula, determined by combining radio-echo soundings, surface velocity data and flow modelling

2013 ◽  
Vol 54 (63) ◽  
pp. 18-24 ◽  
Author(s):  
Daniel Farinotti ◽  
Hugh Corr ◽  
G.Hilmar Gudmundsson
Keyword(s):  
Antarctic Peninsula ◽  
Thickness Distribution ◽  
Surface Velocity ◽  
Ice Thickness ◽  
Ice Shelf ◽  
Ice Flow ◽  
Ice Volume ◽  
Flow Modelling ◽  
Bedrock Topography ◽  
Sparse Measurements

AbstractAn interpolated bedrock topography is presented for Flask Glacier, one of the tributaries of the remnant part of the Larsen B ice shelf, Antarctic Peninsula. The ice thickness distribution is derived by combining direct but sparse measurements from airborne radio-echo soundings with indirect estimates obtained from ice-flow modelling. The ice-flow model is applied to a series of transverse profiles, and a first estimate of the bedrock is iteratively adjusted until agreement between modelled and measured surface velocities is achieved. The adjusted bedrock is then used to reinterpret the radio-echo soundings, and the recovered information used to further improve the estimate of the bedrock itself. The ice flux along the glacier center line provides an additional and independent constraint on the ice thickness. The resulting bedrock topography reveals a glacier bed situated mainly below sea level with sections having retrograde slope. The total ice volume of 120 ±15 km3 for the considered area of 215 km2 corresponds to an average ice thickness of 560 ± 70 m.

scholarly journals Determination of total ice volume and ice-thickness distribution of two glaciers in the Hohe Tauern region, Eastern Alps, from GPR data

2009 ◽  
Vol 50 (51) ◽  
pp. 71-79 ◽  
Author(s):  
D. Binder ◽  
E. Brückl ◽  
K.H. Roch ◽  
M. Behm ◽  
W. Schöner ◽  
...  
Keyword(s):  
Thickness Distribution ◽  
Eastern Alps ◽  
Spatial Density ◽  
Ice Thickness ◽  
Validation Data ◽  
Ice Volume ◽  
Bedrock Topography ◽  
Glacier System ◽  
Ground Penetrating

AbstractGlobal warming is causing an apparent rapid retreat of many glaciers worldwide. In addition to mass-balance investigation, the determination and monitoring of total glacial ice volume and ice-thickness distribution are important parameters for understanding the interactions between climate and the complex glacier system. Because of spatially irregular and sparse datasets, scaling of volume and ice-thickness distribution is often a challenging problem. This study focuses on two small (<2 km2) temperate glaciers in the Hohe Tauern (Eastern Alps) region of central Austria. The period 2003–04 saw the first use of ground-penetrating radar (GPR) to determine the total ice volume and ice-thickness distribution of the two glaciers. A centre frequency of 20 MHz was used in point measuring mode. Despite variable data quality, bedrock reflections up to depths of >100m were identified in the data. The acquired GPR data are irregularly distributed and the spatial density is too low to calculate reasonable bedrock topography with standard interpolation approaches. Thus one main focus of this study was to develop an appropriate interpolation technique. Eventually, kriging technique and a glacial mechanically based interpolation parameter were used. Mean calculated ice thicknesses for the two investigated glaciers are 40–50 m, with a maximum of 150–165 m. No direct validation data are available, so different considerations support the computed bedrock topography.

scholarly journals Changes in ice thickness and flow velocity of Yala Glacier, Langtang Himal, Nepal, from 1982 to 2009

2013 ◽  
Vol 54 (64) ◽  
pp. 157-162 ◽  
Author(s):  
Shin Sugiyama ◽  
Kotaro Fukui ◽  
Koji Fujita ◽  
Kenta Tone ◽  
Satoru Yamaguchi
Keyword(s):  
Flow Velocity ◽  
Surface Elevation ◽  
Ice Thickness ◽  
Glacier Surface ◽  
Ice Flow ◽  
Ice Volume ◽  
Glacier Changes ◽  
Ice Velocity ◽  
Ground Penetrating ◽  
Thinning Rate

Abstract To investigate recent glacier changes in the Himalayan region, we carried out GPS and ground-penetrating radar (GPR) measurements at Yala Glacier, a benchmark glacier in Nepal. Glacier surface elevation and ice thickness were surveyed along a 1.5 km profile from the glacier top to the terminus. Ice flow velocity was measured at five locations by surveying stakes for either 1 year or 4 day periods. Obtained surface elevation and ice velocity were compared with those measured in 1982 and 1996. The mean ice thickness along the radar profile was 36 m in 2009 and the ice has been thinning at rates of-0.69 ±0.25 and -0.75 ± 0.24 m a-1 during the periods 1982-96 and 1996-2009, respectively. The thinning rate increases down-glacier, reaching a magnitude up to -1.8 m a-1 near the terminus from 1996 to 2009. The ice velocity has reduced by &gt;70% from 1982 to 2009 in the lower half of the glacier. By assuming a constant driving stress over the glacier, the total ice volume in 2009 was estimated as 0.061 km3. Our results indicate that Yala Glacier has lost ∼40% of its ice volume over the last 27 years and that the rate of the mass loss has accelerated over the last decade.

scholarly journals The bedrock topography of Starbuck Glacier, Antarctic Peninsula, as determined by radio-echo soundings and flow modeling

2014 ◽  
Vol 55 (67) ◽  
pp. 22-28 ◽  
Author(s):  
Daniel Farinotti ◽  
Edward C. King ◽  
Anika Albrecht ◽  
Matthias Huss ◽  
G. Hilmar Gudmundsson
Keyword(s):  
Antarctic Peninsula ◽  
Thickness Distribution ◽  
Flow Speed ◽  
Ice Thickness ◽  
Ice Flow ◽  
Bedrock Topography ◽  
Radio Echo Sounding ◽  
Field Season ◽  
Thickness Measurements

AbstractA glacier-wide ice-thickness distribution and bedrock topography is presented for Starbuck Glacier, Antarctic Peninsula. The results are based on 90 km of ground-based radio-echo sounding lines collected during the 2012/13 field season. Cross-validation with ice-thickness measurements provided by NASA's IceBridge project reveals excellent agreement. Glacier-wide estimates are derived using a model that calculates distributed ice thickness, calibrated with the radio-echo soundings. Additional constraints are obtained from in situ ice flow-speed measurements and the surface topography. The results indicate a reverse-sloped bed extending from a riegel occurring ~ 5 km upstream of the current grounding line. The deepest parts of the glacier are as much as 500 m below sea level. The calculated total volume of 80.7 ± 7.2 km3 corresponds to an average ice thickness of 312 ± 30 m.

scholarly journals A method to estimate the ice volume and ice-thickness distribution of alpine glaciers

2009 ◽  
Vol 55 (191) ◽  
pp. 422-430 ◽  
Author(s):  
Daniel Farinotti ◽  
Matthias Huss ◽  
Andreas Bauder ◽  
Martin Funk ◽  
Martin Truffer
Keyword(s):  
Mass Balance ◽  
Thickness Distribution ◽  
Ice Thickness ◽  
Average Deviation ◽  
Glacier Surface ◽  
Ice Flow ◽  
Thickness Change ◽  
Ice Volume ◽  
Alpine Glaciers ◽  
Direct Measurements

AbstractSound knowledge of the ice volume and ice-thickness distribution of a glacier is essential for many glaciological applications. However, direct measurements of ice thickness are laborious, not feasible everywhere and necessarily restricted to a small number of glaciers. In this paper, we present a method to estimate the ice-thickness distribution and the total ice volume of alpine glaciers. This method is based on glacier mass turnover and principles of ice-flow mechanics. The required input data are the glacier surface topography, the glacier outline and a set of borders delineating different ‘ice-flow catchments’. Three parameters describe the distribution of the ‘apparent mass balance’, which is defined as the difference between the glacier surface mass balance and the rate of ice-thickness change, and two parameters define the ice-flow dynamics. The method was developed and validated on four alpine glaciers located in Switzerland, for which the bedrock topography is partially known from radio-echo soundings. The ice thickness along 82 cross-profiles can be reproduced with an average deviation of about 25% between the calculated and the measured ice thickness. The cross-sectional areas differ by less than 20% on average. This shows the potential of the method for estimating the ice-thickness distribution of alpine glaciers without the use of direct measurements.

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.

scholarly journals Numerical simulations of the ice flow dynamics of George VI Ice Shelf, Antarctica

2007 ◽  
Vol 53 (183) ◽  
pp. 659-664 ◽  
Author(s):  
Angelika Humbert
Keyword(s):  
High Spatial Resolution ◽  
Thickness Distribution ◽  
Satellite System ◽  
Flow Dynamics ◽  
Ice Thickness ◽  
Ice Shelf ◽  
Ice Flow ◽  
Ice Shelves ◽  
Flow Geometry ◽  
Grounding Line

A diagnostic, dynamic/thermodynamic ice-shelf model is applied to the George VI Ice Shelf, situated in the Bellinghausen Sea, Antarctica. The George VI Ice Shelf has a peculiar flow geometry which sets it apart from other ice shelves. Inflow occurs along the two longest, and almost parallel, sides, whereas outflow occurs on the two ice fronts that are relatively short and situated at opposite ends of the ice shelf. Two data sources were used to derive the ice thickness distribution: conventional radioecho sounding from the British Antarctic Survey was combined with thickness inferred from surface elevation obtained by the NASA GLAS satellite system assuming hydrostatic equilibrium. We simulate the present ice flow over the ice shelf that results from the ice thickness distribution, the inflow at the grounding line and the flow rate factor. The high spatial resolution of the ice thickness distribution leads to very detailed simulations. The flow field has some extraordinary elements (e.g. the stagnation point characteristics resulting from the unusual ice-shelf geometry).

Ice thickness, volume and subglacial relief of Ashuu-Tor, Bordu, Kara-Batkak and Golubina glaciers (Central-Asia) derived from GPR measurements and different approaching methods

2020 ◽  
Author(s):  
Lander Van Tricht ◽  
Philippe Huybrechts ◽  
Jonas Van Breedam ◽  
Johannes Fuerst ◽  
Oleg Rybak ◽  
...  
Keyword(s):  
Central Asia ◽  
Thickness Distribution ◽  
Mass Conservation ◽  
Tien Shan ◽  
Ice Age ◽  
Ice Thickness ◽  
Mountain Range ◽  
Lake Formation ◽  
Ground Penetrating ◽  
Thickness Measurements

&lt;p&gt;Glaciers in the Tien Shan (Central-Asia) mountains contribute a considerable part of the freshwater used for irrigation and households in the dry lowland areas of Kyrgyzstan and its neighbouring countries. Since the Little Ice Age, the total ice mass in this mountain range has been decreasing significantly. However, accurate measurements of the current ice volume and ice thickness distribution in the Tien Shan remain scarce, and accurate data is largely lacking at the local scale. In 2016, 2017 and 2019, we organized 1-month field campaigns in Central-Asia to sound the ice thickness of four different glaciers in the Tien Shan using a Narod ground penetrating radar (GPR) system.&lt;/p&gt;&lt;p&gt;Here, we present and discuss our in-situ ice thickness measurements of the four glaciers. We performed in total more than 1000 GPR soundings. We found a maximum ice thickness of 200 meters in the central part of the southern facing Ashuu-Tor glacier. On both Bordu and Golubina, we measured ice thicknesses up to 140 meters. Kara-Batkak was found to have the thinnest ice which is in agreement to the large average slope of this glacier. We extended all the ice thickness measurements to the entire glacier surfaces using three different methods based on the assumption of plastic flow (method 1) and the principle of mass conservation (method 2 &amp; 3) and assessed their differences.&lt;/p&gt;&lt;p&gt;In this research, we show a detailed ice thickness distribution of Ashuu-Tor, Bordu, Golubina and Kara-Batkak glaciers. This can be used for glaciological modelling and assessing ice and water storage. We also point out the locations of potential lake formation in bedrock overdeepenings as a succession of glacier retreat.&lt;/p&gt;

scholarly journals Estimating the volume of glaciers in the Himalayan–Karakoram region using different methods

2014 ◽  
Vol 8 (6) ◽  
pp. 2313-2333 ◽  
Author(s):  
H. Frey ◽  
H. Machguth ◽  
M. Huss ◽  
C. Huggel ◽  
S. Bajracharya ◽  
...  
Keyword(s):  
Thickness Distribution ◽  
Critical Evaluation ◽  
Estimation Method ◽  
Volume Estimation ◽  
Ice Thickness ◽  
Model Parameters ◽  
Distribution Models ◽  
Ice Volume ◽  
Sensitivity Assessment ◽  
Volume Estimates

Abstract. Ice volume estimates are crucial for assessing water reserves stored in glaciers. Due to its large glacier coverage, such estimates are of particular interest for the Himalayan–Karakoram (HK) region. In this study, different existing methodologies are used to estimate the ice reserves: three area–volume relations, one slope-dependent volume estimation method, and two ice-thickness distribution models are applied to a recent, detailed, and complete glacier inventory of the HK region, spanning over the period 2000–2010 and revealing an ice coverage of 40 775 km2. An uncertainty and sensitivity assessment is performed to investigate the influence of the observed glacier area and important model parameters on the resulting total ice volume. Results of the two ice-thickness distribution models are validated with local ice-thickness measurements at six glaciers. The resulting ice volumes for the entire HK region range from 2955 to 4737 km3, depending on the approach. This range is lower than most previous estimates. Results from the ice thickness distribution models and the slope-dependent thickness estimations agree well with measured local ice thicknesses. However, total volume estimates from area-related relations are larger than those from other approaches. The study provides evidence on the significant effect of the selected method on results and underlines the importance of a careful and critical evaluation.

scholarly journals ICE THICKNESS USING GROUND PENETRATING RADAR AT ZNOSKO GLACIER ON KING GEORGE ISLAND

2020 ◽  
Vol XLII-3/W12-2020 ◽  
pp. 437-439
Author(s):  
C. Bello ◽  
N. Santillan ◽  
A. Cochachin ◽  
S. Arias ◽  
W. Suarez
Keyword(s):  
High Resolution ◽  
Antarctic Peninsula ◽  
Ground Penetrating Radar ◽  
Ice Thickness ◽  
King George Island ◽  
Bedrock Topography ◽  
Antarctic Expedition ◽  
The Future ◽  
The Mean ◽  
Ground Penetrating

Abstract. Ground Penetrating Radar (GPR) survey was carried out to estimate the ice thickness and mapping the bedrock topography at Znosko glacier on King George Island, Antarctic Peninsula during 25th Peruvian Antarctic Expedition (2018). GPR surveying did at 5.2 MHz frequency with a 16 m antenna gap (transmitter and receiver). The mean ice thickness profiles vary from 7 to 123 m across the 350 m profile length. This high-resolution survey also identified a different type of ices and glaciological features which will help in modelling the nature of the glaciers in the future.

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