scholarly journals King George Island ice cap geometry updated with airborne GPR measurements

2011 ◽  
Vol 4 (1) ◽  
pp. 123-139 ◽  
Author(s):  
M. Rückamp ◽  
N. Blindow
Keyword(s):  
Numerical Modelling ◽  
Ice Thickness ◽  
King George Island ◽  
Differential Gps ◽  
Comprehensive Overview ◽  
Data Set ◽  
Airborne Measurements ◽  
Bedrock Topography ◽  
Ice Cap ◽  
Mandatory Requirement

Abstract. Ice geometry is a mandatory requirement for numerical modelling purposes. In this paper we present a consistent data set for the ice thickness, the bedrock topography and the ice surface topography of the King George Island ice cap (Arctowski Icefield and the adjacent central part). The newly data set is composed of groundbased and airborne Ground Penetrating Radar (GPR) and differential GPS (DGPS) measurements, obtained during several field campaigns. Blindow et al. (2010) already provided a comprehensive overview of the groundbased measurements carried out in the safely accessible area of the ice cap. The updated data set incorporates airborne measurements in the heavily crevassed coastal areas. Therefore, in this paper special attention is paid to the airborne measurements by addressing the used instrument, survey, and data processing in more detail. In particular, the inclusion of airborne GPR measurements with the 30 MHz BGR-P30-System developed at the Institute of Geophysics (University of Münster) completes the picture of the ice geometry substantially. The compiled digital elevation model of the bedrock shows a rough, highly variable topography with pronounced valleys, ridges, and troughs. Mean ice thickness is ~240 m, with a maximum value of ~400 m in the surveyed area. Noticeable are bounded areas in the bedrock topography below sea level where marine based ice exists. The provided data set is required as a basis for future monitoring attempts or as input for numerical modelling experiments. The data set is available from the PANGAEA database at doi:10.1594/PANGAEA.770567.

scholarly journals King George Island ice cap geometry updated with airborne GPR measurements

2012 ◽  
Vol 4 (1) ◽  
pp. 23-30 ◽  
Author(s):  
M. Rückamp ◽  
N. Blindow
Keyword(s):  
Numerical Modelling ◽  
Ice Thickness ◽  
King George Island ◽  
Differential Gps ◽  
Comprehensive Overview ◽  
Data Set ◽  
Airborne Measurements ◽  
Bedrock Topography ◽  
Ice Cap ◽  
Mandatory Requirement

Abstract. Ice geometry is a mandatory requirement for numerical modelling purposes. In this paper we present a consistent data set for the ice thickness, the bedrock topography and the ice surface topography of the King George Island ice cap (Arctowski icefield and the adjacent central part). The new data set is composed of ground based and airborne ground penetrating radar (GPR) and differential GPS (DGPS) measurements, obtained during several field campaigns. Blindow et al. (2010) already provided a comprehensive overview of the ground based measurements carried out in the safely accessible area of the ice cap. The updated data set incorporates airborne measurements in the heavily crevassed coastal areas. Therefore, in this paper special attention is paid to the airborne measurements by addressing the instrument used, survey procedure, and data processing in more detail. In particular, the inclusion of airborne GPR measurements with the 30 MHz BGR-P30-System developed at the Institute of Geophysics (University of Münster) completes the picture of the ice geometry substantially. The compiled digital elevation model of the bedrock shows a rough, highly variable topography with pronounced valleys, ridges, and troughs. Mean ice thickness is 240 ± 6 m, with a maximum value of 422 ± 10 m in the surveyed area. Noticeable are bounded areas in the bedrock topography below sea level where marine based ice exists. The provided data set is required as a basis for future monitoring attempts or as input for numerical modelling experiments. The data set is available from the PANGAEA database at http://dx.doi.org/10.1594/PANGAEA.770567.

scholarly journals Dynamics of the ice cap on King George Island, Antarctica: field measurements and numerical simulations

2010 ◽  
Vol 51 (55) ◽  
pp. 80-90 ◽  
Author(s):  
Martin Rückamp ◽  
Norbert Blindow ◽  
Sonja Suckro ◽  
Matthias Braun ◽  
Angelika Humbert
Keyword(s):  
Air Temperature ◽  
Water Layer ◽  
Climatic Conditions ◽  
King George Island ◽  
Differential Gps ◽  
Ice Flow ◽  
Climate Conditions ◽  
Ice Cap ◽  
Ice Surface ◽  
Mean Annual Air Temperature

AbstractKing George Island is located at the northern tip of the Antarctic Peninsula, which is influenced by maritime climate conditions. The observed mean annual air temperature at sea level is –2.4˚C. Thus, the ice cap is regarded as sensitive to changing climatic conditions. Ground-penetrating radar surveys indicate a partly temperate ice cap with an extended water layer at the firn/ice transition of the up to 700 m high ice cap. Measured firn temperatures are close to 0˚C at the higher elevations, and they differ considerably from the measured mean annual air temperature. The aim of this paper is to present ice-flow dynamics by means of observations and simulations of the flow velocities. During several field campaigns from 1997/98 to 2008/09, ice surface velocities were derived with repeated differential GPS measurements. Ice velocities vary from 0.7 m a−1 at the dome to 112.1 m a−1 along steep slopes. For the western part of the ice cap a three-dimensional diagnostic full-Stokes model was applied to calculate ice flow. Parameters of the numerical model were identified with respect to measured ice surface velocities. The simulations indicate cold ice at higher elevations, while temperate ice at lower elevations is consistent with the observations.

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.

scholarly journals Area, volume and mass changes of southeast Vatnajökull ice cap, Iceland, from the Little Ice Age maximum in the late 19th century to 2010

2014 ◽  
Vol 8 (5) ◽  
pp. 4681-4735 ◽  
Author(s):  
H. Hannesdóttir ◽  
H. Björnsson ◽  
F. Pálsson ◽  
G. Aðalgeirsdóttir ◽  
S. Guðmundsson
Keyword(s):  
Mass Balance ◽  
Little Ice Age ◽  
Relative Volume ◽  
Aerial Images ◽  
Ice Age ◽  
Volume Changes ◽  
Data Set ◽  
Bedrock Topography ◽  
Ice Cap ◽  
Geodetic Mass Balance

Abstract. Area and volume changes and the average geodetic mass balance of the non-surging outlet glaciers of southeast Vatnajökull ice cap, Iceland, during different time periods between ~1890 and 2010, are derived from a multi-temporal glacier inventory. A series of digital elevation models (DEMs) (∼1890, 1904, 1936, 1945, 1989, 2002, 2010) have been compiled from glacial geomorphological features, historical photographs, maps, aerial images, DGPS measurements and a LiDAR survey. Given the mapped bedrock topography we estimate relative volume changes since the end of the Little Ice Age (LIA) ~1890. The variable dynamic response of the outlets, assumed to have experienced similar climate forcing, is related to their different hypsometry, bedrock topography, and the presence of proglacial lakes. In the post-LIA period the glacierized area decreased by 164 km2 and the glaciers had lost 10–30% of their ~1890 area by 2010. The glacier surface lowered by 150–270 m near the terminus and the outlet glaciers collectively lost 60 ± 8 km3 of ice, which is equivalent to 0.154 ± 0.02 mm of sea level rise. The relative volume loss of individual glaciers was in the range of 15–50%, corresponding to a geodetic mass balance between −0.70 and −0.32 m w.e. a−1. The rate of mass loss was most negative in the period 2002–2010, on average −1.34 ± 0.12 m w.e. a−1, which lists among the most negative mass balance values recorded worldwide in the early 21st century. From the data set of volume and area of the outlets, spanning the 120 years post-LIA period, we evaluate the parameters of a volume-area power law scaling relationship.

scholarly journals Study of Lange Glacier on King George Island, Antarctica

1999 ◽  
Vol 29 ◽  
pp. 202-206 ◽  
Author(s):  
Yu.Ya. Macheret ◽  
M.Yu. Moskalevsky
Keyword(s):  
Climate Warming ◽  
Drainage Basin ◽  
Close Relation ◽  
South Shetland Islands ◽  
Ice Thickness ◽  
King George Island ◽  
Outlet Glacier ◽  
Ice Cap ◽  
Radio Echo Sounding ◽  
Subglacial Topography

AbstractThe results of ground-based radio-echo sounding collected in 1995 and 1996-97 in the drainage basin of Lange Glacier, a tidewater outlet glacier on King George Island, Antarctica, are presented and discussed. Ice-thickness and bedrock-elevation maps, constructed for the upper non-crevassed part of the glacier, show a close relation between its surface and subglacial topography and indicate the main directions of ice runoff from this area where the ice thickness reaches 308 m. A retreat of the glacier front by 1 km since 1956 occurred against a background of climate warming by 1.4°C on the South Shetland Islands during the last five decades, while a neighboring unnamed glacier advanced by 0.6 km and the northern ice-cap margin on King George Island was approximately stationary. To understand the reasons for the different responses of these ice masses to current climate warming in this region of West Antarctica, further studies including mass-balance and ice-velocity observations and numerical modeling are needed.

scholarly journals Ice thickness and volume of the Renland Ice Cap, East Greenland

2021 ◽  
pp. 1-13
Author(s):  
Iben Koldtoft ◽  
Aslak Grinsted ◽  
Bo M. Vinther ◽  
Christine S. Hvidberg
Keyword(s):  
Surface Topography ◽  
Climate Model ◽  
Thickness Distribution ◽  
High Elevation ◽  
Surface Velocity ◽  
Ice Thickness ◽  
Model Parameters ◽  
East Greenland ◽  
Ice Volume ◽  
Ice Cap

Abstract To assess the amount of ice volume stored in glaciers or ice caps, a method to estimate ice thickness distribution is required for glaciers where no direct observations are available. In this study, we use an existing inverse method to estimate the bedrock topography and ice thickness of the Renland Ice Cap, East Greenland, using satellite-based observations of the surface topography. The inverse approach involves a procedure in which an ice dynamical model is used to build-up an ice cap in steady state with climate forcing from a regional climate model, and the bedrock is iteratively adjusted until the modelled and observed surface topography match. We validate our model results against information from airborne radar data and satellite observed surface velocity, and we find that the inferred ice thickness and thereby the stored total volume of the ice cap is sensitive to the assumed ice softness and basal slipperiness. The best basal model parameters for the Renland Ice Cap are determined and the best estimated total ice volume of 384 km3 is found. The Renland Ice Cap is particularly interesting because of its location at a high elevation plateau and hence assumed low sensitivity to climate change.

scholarly journals Satellite-based sea ice thickness changes in the Laptev Sea from 2002 to 2017: comparison to mooring observations

2020 ◽  
Vol 14 (7) ◽  
pp. 2189-2203
Author(s):  
H. Jakob Belter ◽  
Thomas Krumpen ◽  
Stefan Hendricks ◽  
Jens Hoelemann ◽  
Markus A. Janout ◽  
...  
Keyword(s):  
Sea Ice ◽  
Source Region ◽  
European Space Agency ◽  
The Arctic ◽  
Ice Thickness ◽  
Laptev Sea ◽  
Validation Data ◽  
Data Set ◽  
Sea Ice Thickness ◽  
The Laptev Sea

Abstract. The gridded sea ice thickness (SIT) climate data record (CDR) produced by the European Space Agency (ESA) Sea Ice Climate Change Initiative Phase 2 (CCI-2) is the longest available, Arctic-wide SIT record covering the period from 2002 to 2017. SIT data are based on radar altimetry measurements of sea ice freeboard from the Environmental Satellite (ENVISAT) and CryoSat-2 (CS2). The CCI-2 SIT has previously been validated with in situ observations from drilling, airborne remote sensing, electromagnetic (EM) measurements and upward-looking sonars (ULSs) from multiple ice-covered regions of the Arctic. Here we present the Laptev Sea CCI-2 SIT record from 2002 to 2017 and use newly acquired ULS and upward-looking acoustic Doppler current profiler (ADCP) sea ice draft (VAL) data for validation of the gridded CCI-2 and additional satellite SIT products. The ULS and ADCP time series provide the first long-term satellite SIT validation data set from this important source region of sea ice in the Transpolar Drift. The comparison of VAL sea ice draft data with gridded monthly mean and orbit trajectory CCI-2 data, as well as merged CryoSat-2–SMOS (CS2SMOS) sea ice draft, shows that the agreement between the satellite and VAL draft data strongly depends on the thickness of the sampled ice. Rather than providing mean sea ice draft, the considered satellite products provide modal sea ice draft in the Laptev Sea. Ice drafts thinner than 0.7 m are overestimated, while drafts thicker than approximately 1.3 m are increasingly underestimated by all satellite products investigated for this study. The tendency of the satellite SIT products to better agree with modal sea ice draft and underestimate thicker ice needs to be considered for all past and future investigations into SIT changes in this important region. The performance of the CCI-2 SIT CDR is considered stable over time; however, observed trends in gridded CCI-2 SIT are strongly influenced by the uncertainties of ENVISAT and CS2 and the comparably short investigation period.

scholarly journals Climatic Records from the Dunde Ice Cap, China

1988 ◽  
Vol 10 ◽  
pp. 178-182 ◽  
Author(s):  
Lonnie G. Thompson ◽  
Wu Xiaoling ◽  
Ellen Mosley-Thompson ◽  
Xie Zichu
Keyword(s):  
Accumulation Rate ◽  
Ice Core ◽  
Average Thickness ◽  
The Past ◽  
Bedrock Topography ◽  
Ice Cap ◽  
Pulse Radar ◽  
Oxygen Isotope Ratios ◽  
Ice Core Record ◽  
Climatic Record

Results from the first glaciological investigation of the Dunde ice cap demonstrate that a long, highly temporally resolvable climatic ice-core record is preserved in this ice cap. Measurements of stratigraphy, microparticle concentrations, liquid conductivity, and oxygen-isotope ratios from three snow pits in 1984 suggest that the annual accumulation is approximately 200 mm (water equivalent). Measurement of microparticle concentrations and conductivities of pit samples collected in 1986 confirm the existence of annual dust layers and an annual accumulation rate of ∼200 mm/year over the past 5 years. Bore-hole temperatures of –5.4°C at 30 m indicate that the ice cap is polar. Mono-pulse radar depth determinations yield an average thickness of 140 m, which (coupled with the smooth bedrock topography and the current accumulation rate) suggest that the Dunde ice cap should contain at least a 3000 year climatic record. A drilling program to recover that record from this subtropical location is planned for 1987.

Estimating the ice thickness of the Müller Ice Cap using an inversion of the shallow ice approximation

2021 ◽  
Author(s):  
Ann-Sofie Priergaard Zinck ◽  
Aslak Grinsted
Keyword(s):  
Remote Sensing Data ◽  
The Arctic ◽  
Ice Thickness ◽  
Potential Contribution ◽  
Mean Squared Errors ◽  
Ice Caps ◽  
Ice Cap ◽  
Regression Parameters ◽  
Digital Elevation ◽  
Elevation Model

<p><span>The ice thickness of the Müller Ice Cap, Arctic Canada, is estimated using regression parameters obtained from an inversion of the shallow ice approximation by the use of a single Operation IceBridge flight line in combination with the glacier outline, surface slope, and elevation. The model is compared with an iterative inverse method of estimating the bedrock topography using PISM as a forward model. In both models the surface elevation is given by the Arctic Digital Elevation Model. The root mean squared errors of the ice thickness on the ice cap is 131 m and 139 m for the shallow ice inversion and the PISM model, respectively. Including the outlet glaciers increases the root mean squared errors to 136 m and 396 m, respectively. </span></p><p><span>The simplicity of the shallow ice inversion model, combined with the good results and the fact that only remote sensing data is needed, means that there is a possibility of applying this model in a global glacier thickness estimate by using the Randolph Glacier Inventory. Most global glacier estimates only provide the volume and not the ice thickness of the glaciers. Hence, global ice thickness models is of great importance in quantifying the potential contribution of sea level rise from the glaciers and ice caps around the globe. </span></p>

scholarly journals A 40 Year Record in an Ice Core from the Dunde Ice Cap, China (Abstract)

1988 ◽  
Vol 10 ◽  
pp. 221 ◽  
Author(s):  
Wu Xiaoling ◽  
Lonnie G. Thompson
Keyword(s):  
Oxygen Isotope ◽  
Ice Core ◽  
Field Work ◽  
Tibet Plateau ◽  
Ice Thickness ◽  
Ice Cap ◽  
Pulse Radar ◽  
The North ◽  
Isotope Profile ◽  
Isotope Content

A cooperative glacio-climatological ice-core drilling and analysis program, administered by LIGC and BPRC, has been carried out since 1984. The major objective of this study is to extract from the Dunde ice cap records of the general environmental conditions, which include drought, volcanic activity, moisture sources, glacier net balance and possibly temperature over the last 3000 years. In 1984 a group of 18 Chinese scientists and an American scientist spent 6 weeks on the Dunde ice cap. The central objective of their research was to evaluate the potential of the ice cap to yield a lengthy ice-core climate record. Results of the 1984 field work and 1985 laboratory analysis are submitted here. The Dunde ice cap (38°96′N, 96°24.5′E) is located in the north-eastern section of the Tibet plateau, China. Its length is 10.9 km; the width varies from 2.5 to 7.5 km. The total area of the ice cap is 57 km2. A 16 m core was drilled at the first site, located on a flat part of the ice cap, 5150 m a.s.l. A 10.2 m ice core was drilled at the ice cap summit (5300 m). A series of shallow cores and 2 m pits were excavated at each of the two sites and in the lower section of the ice cap. A mono-pulse radar unit was used to determine ice thickness. The ice thickness ranged between 94 and 167 m, with an average thickness of 140 m. Using a thermistor cable, minimum temperatures of −9.1° and −9.5 °C were measured in the 16 m hole and 10.2 m hole respectively. Microparticle analysis of the ice core from the Dunde ice cap revealed a very high dust content, on average 16 × 105 particles (≥0.63 to ≤16 μ in diameter) per ml of sample, i.e. 3−4 times higher than the microparticle content in the Quelccaya ice cap, Peru, and 100 times higher than in the core from Byrd Station, Antarctica. Oxygen-isotope content ranged between −12 and −14 per mil. Initially it was anticipated that the oxygen-isotope content would produce a more negative value in the Dunde ice cap. More work is required to explain the mechanism controlling δ18o variation in the ice core from the Dunde ice cap. The microparticles, oxygen-isotope content, conductivity, and tritium measurements, together with stratigraphy, temperature and density, are presented in the figures. The 40 year net-balance record reconstructed from the ice-core and oxygen-isotope profile is in good agreement with data from precipitation and major temperature trends obtained for the last 30 years from Delingha meteorological station, which is located 160 km south-east of the ice cap.

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