Application of radar and seismic methods for the investigation of temperate glaciers

Navarro, Francisco; Macheret, Yu. Ya.; Benjumea, Beatriz

doi:10.1016/j.jappgeo.2004.11.002

Cited by 54 publications

(60 citation statements)

References 39 publications

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“…The annual average temperature at Juan Carlos I Station (12 m a.s.l., in Hurd Peninsula) between 1988 and 2011 was −0.9 • C, with average summer (DJF) and winter (JJA) temperatures of 2.4 and −4.4 • C, respectively (Osmanoglu et al, 2014). The main glaciological studies in Hurd Peninsula include cartography of volcanic ash layers (Palà et al, 1999;Ximenis, 2001;Molina, 2014), shallow ice coring , numerical modeling of glaciers dynamics (Martín et al, 2004;Otero et al, 2010), analysis of glacier volume changes 1957-2000 (Molina et al, 2007), seismic and ground-penetrating radar surveys (Benjumea et al, 1999(Benjumea et al, , 2001(Benjumea et al, , 2003Navarro et al, 2005Navarro et al, , 2009, modeling of melting (Jonsell et al, 2012), massbalance observations Ximenis, 2001;Navarro et al, 2013) and geomorphological and glacier dynamics studies (Ximenis et al, 2000;Molina, 2014). Glaciological studies covering the whole Livingston Island include the analysis of Livingston ice cap front position changes 1956-1996, ground-penetrating radar surveys ) and estimates of ice discharge to the ocean (Osmanoglu et al, 2014).…”

Section: Introduction: Study Area and Backgroundmentioning

confidence: 99%

Geomatic methods applied to the study of the front position changes of Johnsons and Hurd Glaciers, Livingston Island, Antarctica, between 1957 and 2013

Cielos

Mata²,

Galilea

et al. 2016

Earth Syst. Sci. Data

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Abstract. Various geomatic measurement techniques can be efficiently combined for surveying glacier fronts. Aerial photographs and satellite images can be used to determine the position of the glacier terminus. If the glacier front is easily accessible, the classic surveys using theodolite or total station, GNSS (Global Navigation Satellite System) techniques, laser-scanner or close-range photogrammetry are possible. When the accessibility to the glacier front is difficult or impossible, close-range photogrammetry proves to be useful, inexpensive and fast. In this paper, a methodology combining photogrammetric methods and other techniques is applied to determine the calving front position of Johnsons Glacier. Images taken in 2013 with an inexpensive nonmetric digital camera are georeferenced to a global coordinate system by measuring, using GNSS techniques, support points in accessible areas close to the glacier front, from which control points in inaccessible points on the glacier surface near its calving front are determined with theodolite using the direct intersection method. The front position changes of Johnsons Glacier during the period 1957-2013, as well as those of the land-terminating fronts of Argentina, Las Palmas and Sally Rocks lobes of Hurd glacier, are determined from different geomatic techniques such as surface-based GNSS measurements, aerial photogrammetry and satellite optical imagery. This provides a set of frontal positions useful, e.g., for glacier dynamics modeling and mass balance studies.

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Section: Introduction: Study Area and Backgroundmentioning

confidence: 99%

Geomatic methods applied to the study of the front position changes of Johnsons and Hurd Glaciers, Livingston Island, Antarctica, between 1957 and 2013

Cielos

Mata²,

Galilea

et al. 2016

Earth Syst. Sci. Data

View full text Add to dashboard Cite

show abstract

“…Although crystal orientation and the presence of soluble and insoluble impurities can also affect radar velocity, in warm ice we expect water to play the most significant role. The geometry of diffraction hyperbolae on common offset surveys depends on radar velocity, meaning that velocity estimates from deeper within glacier-ice can be derived either directly (Moore et al, 1999;Benjumea et al, 2003;Navarro et al, 2005) or by migration processing (Bradford and Harper, 2005). However, unless 3-D data are collected, such techniques assume the subsurface objects causing hyperbolae lie directly beneath the survey line, which can cause errors in the velocity estimates if in fact they originate from offline or from linear features that are not perpendicular to the survey.…”

Section: Introductionmentioning

confidence: 99%

Water-Content of Glacier-Ice: Limitations on Estimates from Velocity Analysis of Surface Ground-Penetrating Radar Surveys

Murray

Booth

Rippin

2007

JEEG

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The rheology of ice is strongly controlled by its liquid water content. Since water content and its distribution also exert a strong control on radar propagation velocity and attenuation, this provides a potential remote technique for assessing ice-water content. A suite of surface ground-penetrating radar (GPR) surveys have been undertaken on two glaciers, Tsanfleuron Glacier in the European Alps and Bakaninbreen, Svalbard in order to determine their water content variation with depth. Common-offset surface radar profiling shows both glaciers have a two-layered structure, with a shallow layer characterised by low returned radar power and a deeper layer characterised by strong scattering. The thickness of these layers varies rapidly across the glaciers. In order to provide a robust interpretation of the properties of the layers within these glaciers we present a quantitative semblance analysis of two common midpoint surveys, making estimates of layer thickness and water content. This analysis includes a Monte Carlo estimate of the likely resolution of these estimates, as well as of the effects of the nonminimum-phase nature of the GPR wavelet. In Tsanfleuron Glacier, the shallow layer consists of relatively dry ice with an estimated water content of 1.18 (+0.15, 20.32)%, whereas the deeper layer is interpreted as containing small water bodies, 3.90 (+1.87, 21.35)% by volume. At Bakaninbreen, the shallow layer contains no water and the deeper layer 1.29 (+1.68, 21.14)% water. At both glaciers the deeper layer will undoubtedly be rheologically softer, with implications for ice dynamics; furthermore, the layer will provide a store for a substantial water volume with important implications for the glacier's water system. The uncertainty in the calculated water content is, however, significant in terms of ice dynamics, meaning that alternative methods of assessing water content, possibly using borehole radar, are required to provide the input for predictive models of glacier flow.

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“…The GPR shows strong reflection responses at the contact zone between the plateau glacier ice and the bedrock underneath, which suggests the presence of water at the ice‐bed interface, as is typical for temperate glaciers (Navarro et al . ). With apparently no frozen ground underlying the glaciers and the high rate of glacial retreat (100 m within 15 years) we expect the permafrost in the glacier fore‐field to be a young feature.…”

Section: Study Areamentioning

confidence: 97%

The use of GPR to detect active layers in young periglacial terrain of Livingston Island, Maritime Antarctica

Schwamborn

Wagner

Hubberten

2008

Near Surface Geophysics

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The South Shetland Islands offer ice‐free margins with periglacial surfaces that are only a few decades old after the recent glacier retreat. Ground‐penetrating radar (GPR) profiling was used to acquire information on young permafrost occurrence as deduced from active layer advance. Local GPR measurements included grids of parallel single‐offset 2D reflection profiles and multi‐offset measurements to determine wave velocity in the ground. Excavations served to determine the sedimentary composition and to backup GPR profile interpretation. GPR results show that the active layer could easily be traced at a site 140 m above sea level (asl), which is placed in volcanic soil. In contrast, GPR data were ambiguous at a site low in altitude (35 m asl), where frozen and unfrozen ground was imaged next to each other and GPR interpretation relied on ground verification.

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Application of radar and seismic methods for the investigation of temperate glaciers

Cited by 54 publications

References 39 publications

Geomatic methods applied to the study of the front position changes of Johnsons and Hurd Glaciers, Livingston Island, Antarctica, between 1957 and 2013

Geomatic methods applied to the study of the front position changes of Johnsons and Hurd Glaciers, Livingston Island, Antarctica, between 1957 and 2013

Water-Content of Glacier-Ice: Limitations on Estimates from Velocity Analysis of Surface Ground-Penetrating Radar Surveys

The use of GPR to detect active layers in young periglacial terrain of Livingston Island, Maritime Antarctica

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