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Martin J. Siegert - One of the best experts on this subject based on the ideXlab platform.
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removal of strip noise in Radio Echo sounding data using combined wavelet and 2 d dft filtering
Annals of Glaciology, 2020Co-Authors: Bangbing Wang, Donald D Blankenship, Duncan A Young, Bo Sun, Jiaxin Wang, Jamin S Greenbaum, Jingxue Guo, Laura Lindzey, Xiangbin Cui, Martin J. SiegertAbstract:Radio-Echo sounding (RES) can be used to understand ice-sheet processes, englacial flow structures and bed properties, making it one of the most popular tools in glaciological exploration. However, RES data are often subject to ‘strip noise’, caused by internal instrument noise and interference, and/or external environmental interference, which can hamper measurement and interpretation. For example, strip noise can result in reduced power from the bed, affecting the quality of ice thickness measurements and the characterization of subglacial conditions. Here, we present a method for removing strip noise based on combined wavelet and two-dimensional (2-D) Fourier filtering. First, we implement discrete wavelet decomposition on RES data to obtain multi-scale wavelet components. Then, 2-D discrete Fourier transform (DFT) spectral analysis is performed on components containing the noise. In the Fourier domain, the 2-D DFT spectrum of strip noise keeps its linear features and can be removed with a ‘targeted masking’ operation. Finally, inverse wavelet transforms are performed on all wavelet components, including strip-removed components, to restore the data with enhanced fidelity. Model tests and field-data processing demonstrate the method removes strip noise well and, incidentally, can remove the strong first reflector from the ice surface, thus improving the general quality of radar data.
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accidents and opportunities a history of the Radio Echo sounding of antarctica 1958 79
The British Journal for the History of Science, 2008Co-Authors: Simone Turchetti, Katrina Dean, Simon Naylor, Martin J. SiegertAbstract:This paper explores the history of Radio Echo-sounding (RES), a technique of glaciological surveying that from the late 1960s has been used to examine Antarctica's sub-glacial morphology. Although the origins of RES can be traced back to two accidental findings, its development relied upon the establishment of new geopolitical conditions, which in the 1960s typified Antarctica as a continent devoted to scientific exploration. These conditions extended the influence of prominent glaciologists promoting RES and helped them gather sufficient support to test its efficiency. The organization and implementation of a large-scale research programme of RES in Antarctica followed these developments. The paper also examines the deployment of RES in Antarctic explorations, showing that its completion depended on the availability of technological systems of which RES was an integral part.
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Radio Echo sounding over polar ice masses
Journal of Environmental and Engineering Geophysics, 2007Co-Authors: R Bingham, Martin J. SiegertAbstract:Radio-Echo sounding (RES) constitutes the principal means by which glaciologists investigate the subsurface properties of the polar ice sheets and ice caps. Developed in the 1960s as a method for locating and mapping the subglacial interface beneath extensive regions of icecovered terrain, thereby to constrain ice volume and morphology, it was quickly discovered that RES supplies numerous additional cryospheric parameters, including strong reflectors derived from subglacial lakes, and isochronous internal reflectors derived from burial of snow deposition events. Soon after its establishment, RES was integrated into long-range aircraft primarily to image the bed across Antarctica and Greenland (1960s/1970s). More recent airborne campaigns (1980s/1990s), while supplementing this coverage and extending to the ice caps of the High Arctic, have utilised only short-range aircraft, and were designed explicitly to support specific scientific studies, such as locating optimal sites for deep ice-coring, constraining the dimensions of subglacial lakes, or resolving internal layers for studies of ice sheet mass balance, form and flow. In parallel with these developments, ground-based (over-snow) RES equipment has also been used to investigate the englacial and subglacial conditions at a number of key locations across the polar ice sheets. This article discusses the many scientific advances which have resulted from these efforts, and offers recommendations for future developments in terms of (i) reanalysis of existing data and (ii) suggestions for future RES campaigns.
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spatial stability of ice stream d and its tributaries west antarctica revealed by Radio Echo sounding and interferometry
Annals of Glaciology, 2003Co-Authors: Martin J. Siegert, Antony J Payne, Ian JoughinAbstract:It has been shown recently that ice streams are fed by fast-flowing tributaries occupying well-defined subglacial troughs and with shared source areas. Here, ice-penetrating Radio-Echo sounding (RES) data are analyzed in conjunction with ice surface velocities derived from interferometric synthetic aperture radar (InSAR), to determine the englacial properties of tributaries feeding Ice Stream D, West Antarctica. All of Ice Stream D’s tributaries are coincident with ` buckled’’ internal ice-sheet layers, most probably deformed by the processes responsible for enhanced ice flow. Between the tributaries well-preserved internal layers occur. The data reveal that no lateral migration of the ice-stream tributaries has occurred recently. This is consistent with thermomechanical ice-flow modelling, which indicates that the flow of Ice Stream D is controlled by a subglacial trough and is unaffected by changes to the flow of neighbouring Ice Stream C.
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on the origin nature and uses of antarctic ice sheet Radio Echo layering
Progress in Physical Geography, 1999Co-Authors: Martin J. SiegertAbstract:Airborne Radio-Echo sounding (RES) data display layering within the Antarctic ice sheet. At ice depths below 1000m these layers are caused by horizons of ice with relatively high acidity which were originally deposited on the ice surface after large volcanic events. Layering which is less than 1000 m from the ice surface can also be due to variation in ice density. Theoretically, therefore, internal RES layering below 1000 m should represent isochronous planes. This theory is upheld under examination of existing RES data where internal layers have been observed to follow the rules of superposition. For example, RES layers are deposited as discrete bands, fold and fault in a manner analogous to geological features, never cross over each other and, in an undisturbed deposit, have a depth-age relationship which means that the oldest layers are located at the lowest level. Moreover, the location of internal layering is independent of Radiowave receiver altitude, the frequency of the Radiowave does not affect ...
Daniel Steinhage - One of the best experts on this subject based on the ideXlab platform.
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comparison of measurements from different Radio Echo sounding systems and synchronization with the ice core at dome c antarctica
The Cryosphere, 2017Co-Authors: Anna Winter, Hugh F J Corr, John Paden, Daniel Steinhage, Stefano Urbini, Emily Arnold, Donald D Blankenship, Marie G P Cavitte, Duncan A Young, Olaf EisenAbstract:Abstract. We present a compilation of Radio-Echo sounding (RES) measurements of five radar systems (AWI, BAS, CReSIS, INGV and UTIG) around the EPICA Dome C (EDC) drill site, East Antarctica. The aim of our study is to investigate the differences of the various systems in their resolution of internal reflection horizons (IRHs) and bed topography, penetration depth and capacity of imaging the basal layer. We address the questions of the compatibility of existing radar data for common interpretation and the suitability of the individual systems for reconnaissance surveys. We find that the most distinct IRHs and IRH patterns can be identified and transferred between most data sets. Considerable differences between the RES systems exist in range resolution and depiction of the bottom-most region. Considering both aspects, which we judge as crucial factors in the search for old ice, the CReSIS and the UTIG systems are the most suitable ones. In addition to the RES data set comparison we calculate a synthetic radar trace from EDC density and conductivity profiles. We identify 10 common IRHs in the measured RES data and the synthetic trace. We then conduct a sensitivity study for which we remove certain peaks from the input conductivity profile. As a result the respective reflections disappear from the modeled radar trace. In this way, we establish a depth conversion of the measured travel times of the IRHs. Furthermore, we use these sensitivity studies to investigate the cause of observed reflections. The identified IRHs are assigned ages from the EDC's timescale. Due to the isochronous character of these conductivity-caused IRHs, they are a means to extend the Dome C age structure by tracing the IRHs along the RES profiles.
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Radio Echo sounding measurements and ice core synchronization at dome c antarctica
The Cryosphere Discussions, 2016Co-Authors: Anna Winter, Hugh F J Corr, John Paden, Daniel Steinhage, Stefano Urbini, Emily Arnold, Donald D Blankenship, Marie G P Cavitte, Duncan A Young, Olaf EisenAbstract:We present a compilation of Radio-Echo sounding (RES) measurements of five radar systems (AWI, BAS, CReSIS, INGV and UTIG) around the EPICA Dome C (EDC) drill site, East Antarctica. The aim of our study is to investigate the differences of the various systems in their resolution of internal reflection horizons (IRHs) and bedrock topography, penetration depth, and quality of imaging the basal layer. We address the questions of the compatibility of existing radar data for common interpretation, and the suitability of the individual systems for Oldest Ice reconnaissance surveys. We find that the most distinct 5 IRHs and IRH patterns can be identified and transferred between most data sets. Considerable differences between the RES systems exist in range resolution and depiction of the basal layer. Considering both aspects, which we judge as crucial factors in the search for old ice, the CReSIS and the UTIG systems are the most valuable ones. In addition to the RES data set comparison we calculate a synthetic radar trace from EDC density and conductivity profiles. We identify ten common IRHs in the measured RES data and the synthetic trace. The reflection-causing conductivity sections are determined by sensitivity studies with the 10 synthetic trace. In this way, we accomplish an accurate two-way travel time to depth conversion for the reflectors, without having to use a precise velocity-depth function that would accumulate depth uncertainties with increasing depth. The identified IRHs are assigned with the AICC2012 time scale age. Due to the isochronous character of these conductivity-caused IRHs, they are a means to extend the Dome C age structure by tracing the IRHs along the RES profiles.
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internal structure of the ice sheet between kohnen station and dome fuji antarctica revealed by airborne Radio Echo sounding
Annals of Glaciology, 2013Co-Authors: Daniel Steinhage, Uwe Nixdorf, Sepp Kipfstuhl, Heinrich MillerAbstract:This study aims to demonstrate that deep ice cores can be synchronized using internal horizons in the ice between the drill sites revealed by airborne Radio-Echo sounding (RES) over a distance of >1000 km, despite significant variations in glaciological parameters, such as accumulation rate between the sites. In 2002/03 a profile between the Kohnen station and Dome Fuji deep ice-core drill sites, Antarctica, was completed using airborne RES. The survey reveals several continuous internal horizons in the RES section over a length of 1217 km. The layers allow direct comparison of the deep ice cores drilled at the two stations. In particular, the counterpart of a visible layer observed in the Kohnen station (EDML) ice core at 1054 m depth has been identified in the Dome Fuji ice core at 575 m depth using internal RES horizons. Thus the two ice cores can be synchronized, i.e. the ice at 1560 m depth (at the bottom of the 2003 EDML drilling) is $49 ka old according to the Dome Fuji age/depth scale, using the traced internal layers presented in this study.
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Layer disturbances and the Radio-Echo free zone in ice sheets
The Cryosphere, 2009Co-Authors: Reinhard Drews, Daniel Steinhage, Olaf Eisen, Ilka Weikusat, Sepp Kipfstuhl, Astrid Lambrecht, Frank Wilhelms, Heinrich MillerAbstract:Abstract. Radio-Echo sounding of the Antarctic and Greenlandic ice sheets often reveals a layer in the lowest hundreds of meters above bedrock more or less free of Radio Echoes, known as the Echo-free zone (EFZ). The cause of this feature is unclear, so far lacking direct evidence for its origin. We compare Echoes around the EPICA drill site in Dronning Maud Land, Antarctica, with the dielectric properties, crystal orientation fabrics and optical stratigraphy of the EPICA-DML ice core. We find that Echoes disappear in the depth range where the dielectric contrast is blurred, and where the coherency of the layers in the ice core is lost due to disturbances caused by the ice flow. At the drill site, the EFZ onset at ~2100 m marks a boundary, below which the ice core may have experienced flow induced disturbances on various scales. The onset may indicate changing rheology which needs to be accounted for in the modeling of ice sheet dynamics.
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past and present accumulation rate reconstruction along the dome fuji kohnen Radio Echo sounding profile dronning maud land east antarctica
Annals of Glaciology, 2009Co-Authors: Philippe Huybrechts, Daniel Steinhage, Oleg Rybak, Frank PattynAbstract:We used internal ice layers from a Radio-Echo sounding profile between the Kohnen and Dome Fuji deep drilling sites to infer the spatio-temporal pattern of accumulation rate in this sector of Dronning Maud Land, East Antarctica. Continuous internal reflection horizons can be traced to about half of the ice thickness and have a maximum age of approximately 72.7 ka BP. To infer palaeo- accumulation rates from the dated layers, we derived the thinning functions from a flow calculation with a high-resolution higher-order model of Dronning Maud Land embedded into a three-dimensional thermomechanical model of the Antarctic ice sheet. The method takes into account complex ice-flow dynamics and advection effects that cannot be dealt with using traditional local approaches. We selected seven time intervals over which we determine the average accumulation rate and average surface temperature at the place and time of origin of the layer particles. Our results show lower accumulation rates along eastern parts of the profile for the late Holocene (0-5 ka BP) than are shown by existing maps, which had no surface control points. During the last glacial period we find a substantially lower accumulation rate than predicted by the usual approach linking palaeo-accumulation rates to the condensation temperature above the surface inversion layer. These findings were used to fine-tune the relation between accumulation rate and temperature.
Heinrich Miller - One of the best experts on this subject based on the ideXlab platform.
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internal structure of the ice sheet between kohnen station and dome fuji antarctica revealed by airborne Radio Echo sounding
Annals of Glaciology, 2013Co-Authors: Daniel Steinhage, Uwe Nixdorf, Sepp Kipfstuhl, Heinrich MillerAbstract:This study aims to demonstrate that deep ice cores can be synchronized using internal horizons in the ice between the drill sites revealed by airborne Radio-Echo sounding (RES) over a distance of >1000 km, despite significant variations in glaciological parameters, such as accumulation rate between the sites. In 2002/03 a profile between the Kohnen station and Dome Fuji deep ice-core drill sites, Antarctica, was completed using airborne RES. The survey reveals several continuous internal horizons in the RES section over a length of 1217 km. The layers allow direct comparison of the deep ice cores drilled at the two stations. In particular, the counterpart of a visible layer observed in the Kohnen station (EDML) ice core at 1054 m depth has been identified in the Dome Fuji ice core at 575 m depth using internal RES horizons. Thus the two ice cores can be synchronized, i.e. the ice at 1560 m depth (at the bottom of the 2003 EDML drilling) is $49 ka old according to the Dome Fuji age/depth scale, using the traced internal layers presented in this study.
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Layer disturbances and the Radio-Echo free zone in ice sheets
The Cryosphere, 2009Co-Authors: Reinhard Drews, Daniel Steinhage, Olaf Eisen, Ilka Weikusat, Sepp Kipfstuhl, Astrid Lambrecht, Frank Wilhelms, Heinrich MillerAbstract:Abstract. Radio-Echo sounding of the Antarctic and Greenlandic ice sheets often reveals a layer in the lowest hundreds of meters above bedrock more or less free of Radio Echoes, known as the Echo-free zone (EFZ). The cause of this feature is unclear, so far lacking direct evidence for its origin. We compare Echoes around the EPICA drill site in Dronning Maud Land, Antarctica, with the dielectric properties, crystal orientation fabrics and optical stratigraphy of the EPICA-DML ice core. We find that Echoes disappear in the depth range where the dielectric contrast is blurred, and where the coherency of the layers in the ice core is lost due to disturbances caused by the ice flow. At the drill site, the EFZ onset at ~2100 m marks a boundary, below which the ice core may have experienced flow induced disturbances on various scales. The onset may indicate changing rheology which needs to be accounted for in the modeling of ice sheet dynamics.
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Airborne Radio Echo Sounding Measurements from Novolazarevskaya Skiway, Central Dronning Maud Land, Antarctica
2005Co-Authors: Uwe Meyer, Daniel Steinhage, Uwe Nixdorf, Heinrich MillerAbstract:AbstractDuring the austral summer season 1995/96 the two polar aircraft, Polar2 and Polar4, of the Alfred Wegener Institute (AWI) operated from the Novolazarevskaya skiway to perform aerogeophysical and photogrammetric measurements within the GEOMAUD programme initiated by the BGR.A major part of the airborne work was dedicated towards measurements of the ice thickness and internal reflectors of the ice in the region of the Wohlthatmassiv and the Wegener Inland Ice south of it, related to the EPICA (European Project for Ice Coring in Antarctica) programme. This paper reports about the technique used for the airborne Radio Echo sounding measurements, the logistic setup and results of the airborne Radio Echo sounding survey.
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subglacial topography and internal structure of central and western dronning maud land antarctica determined from airborne Radio Echo sounding
Journal of Applied Geophysics, 2001Co-Authors: Daniel Steinhage, Uwe Meyer, Uwe Nixdorf, Heinrich MillerAbstract:Abstract During five austral summers, from 1994/1995 until 1998/1999, the Alfred Wegener Institute (AWI) carried out a large airborne Radio Echo sounding (RES) survey in Dronning Maud Land (DML), Antarctica. These ice thickness measurements are part of the AWI contribution to the pre-site survey for a deep ice core drill site in DML within the European Project for Ice Coring in Antarctica (EPICA). The survey encompasses more than 90,000 km of RES profiles over DML and the adjacent coastal area, covering more than 1 million km 2 . The lower boundary of the ice sheet could be determined area-wide. Internal horizons occurring in the upper two-thirds of the ice column can also be traced for several hundred kilometers. This work presents the latest maps of the subglacial topography of the investigated area as well as of an internal horizon.
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subglacial topography and internal structure of central and western dronning maud land antarctica determined from airborne Radio Echo sounding
Eighth International Conference on Ground Penetrating Radar, 2000Co-Authors: Daniel Steinhage, Uwe Meyer, Uwe Nixdorf, Heinrich MillerAbstract:During five austral summers, from 1994/95 until 1998/99, the Alfred Wegener Institute (AWI) carried out a large airborne Radio Echo sounding (RES) survey in Dronning Maud Land (DML), Antarctica. These ice thickness measurements are part of the AWI contribution to the pre-site survey for a deep ice core drill site in DML within the European Project for Ice Coring in Antarctica (EPICA). The survey encompasses more than 90000 km RES profiles over DML and the adjacent coastal area, covering more than 1 million km2. The lower boundary of the ice sheet could be determined area-wide. Internal horizons occurring in the upper two thirds of the ice column can also be traced for several hundred kilometers. This work presents the latest maps of the subglacial topography of the investigated area as well as of an internal horizon.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Stefano Urbini - One of the best experts on this subject based on the ideXlab platform.
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airborne Radio Echo sounding res measures on alpine glaciers to evaluate ice thickness and bedrock geometry preliminary results from pilot tests performed in the ortles cevedale group italian alps
Annals of Geophysics, 2017Co-Authors: Stefano Urbini, J. A. Baskaradas, A Zirizzotti, L Cafarella, I E Tabacco, Antonella Senese, Claudio Smiraglia, Guglielmina DiolaiutiAbstract:Radar exploration supports glaciological studies playing several roles in ice exploration such as determining ice thickness and volume, describing ice and snow internal layering and characterizing crevassed areas. The method, widely used with full success on Polar areas, encounters more difficulties when applied to survey mountain glaciers like the Alpine and Himalayan ones. Among them, these difficulties can be addressed to the different physical characteristics of temperate ice and to logistic difficulties related to performing field operations at high elevations on areas where crevasses, seracs and ice-falls are present, making more complicate and complex the glacier surface. In the framework of the SHARE-PAPRIKA and the SHARE-STELVIO Projects, we performed some preliminary measurements on Careser, Sforzellina and Forni glaciers (Ortles-Cevedale Group, Italy), to evaluate efficiency and applicability of a Radio Echo Sounding (RES) instrument specifically designed, developed and modified by the INGV (Istituto Nazionale di Geofisica e Vulcanologia) laboratories. This paper reports the results we obtained investigating each glacier, the hampering factors and the cost to benefit ratio introduced by the airborne survey.
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comparison of measurements from different Radio Echo sounding systems and synchronization with the ice core at dome c antarctica
The Cryosphere, 2017Co-Authors: Anna Winter, Hugh F J Corr, John Paden, Daniel Steinhage, Stefano Urbini, Emily Arnold, Donald D Blankenship, Marie G P Cavitte, Duncan A Young, Olaf EisenAbstract:Abstract. We present a compilation of Radio-Echo sounding (RES) measurements of five radar systems (AWI, BAS, CReSIS, INGV and UTIG) around the EPICA Dome C (EDC) drill site, East Antarctica. The aim of our study is to investigate the differences of the various systems in their resolution of internal reflection horizons (IRHs) and bed topography, penetration depth and capacity of imaging the basal layer. We address the questions of the compatibility of existing radar data for common interpretation and the suitability of the individual systems for reconnaissance surveys. We find that the most distinct IRHs and IRH patterns can be identified and transferred between most data sets. Considerable differences between the RES systems exist in range resolution and depiction of the bottom-most region. Considering both aspects, which we judge as crucial factors in the search for old ice, the CReSIS and the UTIG systems are the most suitable ones. In addition to the RES data set comparison we calculate a synthetic radar trace from EDC density and conductivity profiles. We identify 10 common IRHs in the measured RES data and the synthetic trace. We then conduct a sensitivity study for which we remove certain peaks from the input conductivity profile. As a result the respective reflections disappear from the modeled radar trace. In this way, we establish a depth conversion of the measured travel times of the IRHs. Furthermore, we use these sensitivity studies to investigate the cause of observed reflections. The identified IRHs are assigned ages from the EDC's timescale. Due to the isochronous character of these conductivity-caused IRHs, they are a means to extend the Dome C age structure by tracing the IRHs along the RES profiles.
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Radio Echo sounding measurements and ice core synchronization at dome c antarctica
The Cryosphere Discussions, 2016Co-Authors: Anna Winter, Hugh F J Corr, John Paden, Daniel Steinhage, Stefano Urbini, Emily Arnold, Donald D Blankenship, Marie G P Cavitte, Duncan A Young, Olaf EisenAbstract:We present a compilation of Radio-Echo sounding (RES) measurements of five radar systems (AWI, BAS, CReSIS, INGV and UTIG) around the EPICA Dome C (EDC) drill site, East Antarctica. The aim of our study is to investigate the differences of the various systems in their resolution of internal reflection horizons (IRHs) and bedrock topography, penetration depth, and quality of imaging the basal layer. We address the questions of the compatibility of existing radar data for common interpretation, and the suitability of the individual systems for Oldest Ice reconnaissance surveys. We find that the most distinct 5 IRHs and IRH patterns can be identified and transferred between most data sets. Considerable differences between the RES systems exist in range resolution and depiction of the basal layer. Considering both aspects, which we judge as crucial factors in the search for old ice, the CReSIS and the UTIG systems are the most valuable ones. In addition to the RES data set comparison we calculate a synthetic radar trace from EDC density and conductivity profiles. We identify ten common IRHs in the measured RES data and the synthetic trace. The reflection-causing conductivity sections are determined by sensitivity studies with the 10 synthetic trace. In this way, we accomplish an accurate two-way travel time to depth conversion for the reflectors, without having to use a precise velocity-depth function that would accumulate depth uncertainties with increasing depth. The identified IRHs are assigned with the AICC2012 time scale age. Due to the isochronous character of these conductivity-caused IRHs, they are a means to extend the Dome C age structure by tracing the IRHs along the RES profiles.
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Ice and Bedrock Characteristics Underneath Dome C (Antarctica) From Radio Echo Sounding Data Analysis
IEEE Transactions on Geoscience and Remote Sensing, 2012Co-Authors: Achille Zirizzotti, Lili Cafarella, Stefano UrbiniAbstract:The Radio Echo sounding (RES) system is one of the most widely used active remote sensing techniques for polar ice sheet exploration, including bedrock morphology studies and subglacial lake investigations. Recently, bedrock characterization has been improved through the analysis of radar Echo strength. In this paper, the analysis of the RES signal amplitude has been used to collect information about the controversial problem of electromagnetic ice absorption to highlight areas of high reflectivity variation, ascribable to wet ice-bedrock interfaces. A method to distinguish a wet or dry bedrock-ice interface using a model to describe the internal ice absorption is proposed and discussed. Moreover, the comparison between the ice absorption rates from RES measurements and from European Project for Ice Coring in Antarctica Dome C (Antarctica) ice core conductivity data, the signal amplitude contributions of internal ice layers, and different kinds of rock interface is evaluated. Encouraged by the results, the data analysis led to obtaining a bedrock reflectivity variation map of the Dome C area. This map outlined a wide dispersion of wet/dry rock interfaces in the studied area, indicating the possibility of flowing water along both sides of the Concordia Trench.
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Radio Echo sounding data analysis of the Shackleton Ice Shelf
Annals of Geophysics, 2010Co-Authors: Stefano Urbini, Lili Cafarella, Achille Zirizzotti, Ignazio E. Tabacco, Carla Bottari, J. A. Baskaradas, Neal YoungAbstract:In this study, our initial results are presented for the interpretation of the Radio Echo sounding data collected over the Shackleton Ice Shelf and adjacent ice sheet (East Antarctica) during the 2003/2004 AustralianItalian expedition. The Shackleton Ice Shelf is one of the larger ice shelves of the East Antarctic Ice Sheet. The radar survey provided data relating to ice thickness and bed morphology of the outlet glaciers, and thickness of their floating portions. The glacier grounding lines were determined by assessment of the basal Echo characters. The information derived is compared with data from the BEDMAP database and from other sources.
Uwe Nixdorf - One of the best experts on this subject based on the ideXlab platform.
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internal structure of the ice sheet between kohnen station and dome fuji antarctica revealed by airborne Radio Echo sounding
Annals of Glaciology, 2013Co-Authors: Daniel Steinhage, Uwe Nixdorf, Sepp Kipfstuhl, Heinrich MillerAbstract:This study aims to demonstrate that deep ice cores can be synchronized using internal horizons in the ice between the drill sites revealed by airborne Radio-Echo sounding (RES) over a distance of >1000 km, despite significant variations in glaciological parameters, such as accumulation rate between the sites. In 2002/03 a profile between the Kohnen station and Dome Fuji deep ice-core drill sites, Antarctica, was completed using airborne RES. The survey reveals several continuous internal horizons in the RES section over a length of 1217 km. The layers allow direct comparison of the deep ice cores drilled at the two stations. In particular, the counterpart of a visible layer observed in the Kohnen station (EDML) ice core at 1054 m depth has been identified in the Dome Fuji ice core at 575 m depth using internal RES horizons. Thus the two ice cores can be synchronized, i.e. the ice at 1560 m depth (at the bottom of the 2003 EDML drilling) is $49 ka old according to the Dome Fuji age/depth scale, using the traced internal layers presented in this study.
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Airborne Radio Echo Sounding Measurements from Novolazarevskaya Skiway, Central Dronning Maud Land, Antarctica
2005Co-Authors: Uwe Meyer, Daniel Steinhage, Uwe Nixdorf, Heinrich MillerAbstract:AbstractDuring the austral summer season 1995/96 the two polar aircraft, Polar2 and Polar4, of the Alfred Wegener Institute (AWI) operated from the Novolazarevskaya skiway to perform aerogeophysical and photogrammetric measurements within the GEOMAUD programme initiated by the BGR.A major part of the airborne work was dedicated towards measurements of the ice thickness and internal reflectors of the ice in the region of the Wohlthatmassiv and the Wegener Inland Ice south of it, related to the EPICA (European Project for Ice Coring in Antarctica) programme. This paper reports about the technique used for the airborne Radio Echo sounding measurements, the logistic setup and results of the airborne Radio Echo sounding survey.
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subglacial topography and internal structure of central and western dronning maud land antarctica determined from airborne Radio Echo sounding
Journal of Applied Geophysics, 2001Co-Authors: Daniel Steinhage, Uwe Meyer, Uwe Nixdorf, Heinrich MillerAbstract:Abstract During five austral summers, from 1994/1995 until 1998/1999, the Alfred Wegener Institute (AWI) carried out a large airborne Radio Echo sounding (RES) survey in Dronning Maud Land (DML), Antarctica. These ice thickness measurements are part of the AWI contribution to the pre-site survey for a deep ice core drill site in DML within the European Project for Ice Coring in Antarctica (EPICA). The survey encompasses more than 90,000 km of RES profiles over DML and the adjacent coastal area, covering more than 1 million km 2 . The lower boundary of the ice sheet could be determined area-wide. Internal horizons occurring in the upper two-thirds of the ice column can also be traced for several hundred kilometers. This work presents the latest maps of the subglacial topography of the investigated area as well as of an internal horizon.
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subglacial topography and internal structure of central and western dronning maud land antarctica determined from airborne Radio Echo sounding
Eighth International Conference on Ground Penetrating Radar, 2000Co-Authors: Daniel Steinhage, Uwe Meyer, Uwe Nixdorf, Heinrich MillerAbstract:During five austral summers, from 1994/95 until 1998/99, the Alfred Wegener Institute (AWI) carried out a large airborne Radio Echo sounding (RES) survey in Dronning Maud Land (DML), Antarctica. These ice thickness measurements are part of the AWI contribution to the pre-site survey for a deep ice core drill site in DML within the European Project for Ice Coring in Antarctica (EPICA). The survey encompasses more than 90000 km RES profiles over DML and the adjacent coastal area, covering more than 1 million km2. The lower boundary of the ice sheet could be determined area-wide. Internal horizons occurring in the upper two thirds of the ice column can also be traced for several hundred kilometers. This work presents the latest maps of the subglacial topography of the investigated area as well as of an internal horizon.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
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new maps of the ice thickness and subglacial topography in dronning maud land antarctica determined by means of airborne Radio Echo sounding
Annals of Glaciology, 1999Co-Authors: Daniel Steinhage, Uwe Meyer, Uwe Nixdorf, Heinz MillerAbstract:Since the austral summer 1994/95 the Alfred Wegener Institute (AWI) hascarried out airborne Radio Echo sounding measurements (RES) in Antarctica withits newly designed RES system. Since 1995/96 an ongoing presite survey foran ice coring drill site in Dronning Maud Land (DML) has been carried out.This survey is part of the EPICA programme (European Project for Ice Coring inAntarctica). It covers an area of 948000 km2 with more than 49500 km ofairborne RES obtained from more than 200 hours of flight operation flown from1994-1997. Within this paper first results of the airborne RES survey will begraphically summarized as newly derived maps of the ice thickness and thesubglacial topography as well as a 3D view of surface and subglacial bed andoutcrop topography, revealing a total icevolume of 1.48 million km3.