An improved coherent radar depth sounder

Gogineni, S.; Chuah, T.; Allen, C.; Jezek, Kenneth C.; Moore, Robert K.

doi:10.3189/s0022143000002161

Cited by 67 publications

(53 citation statements)

References 74 publications

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“…The radar system described by Gogineni et al [1998] used the digital signal processor (DSP) developed in 1988 [Xin, 1989]. This DSP system used 8-bit A/D converters with a dynamic range of about 48 dB.…”

Section: System Descriptionmentioning

confidence: 99%

Coherent radar ice thickness measurements over the Greenland ice sheet

Gogineni¹,

Tammana²,

Braaten³

et al. 2001

J. Geophys. Res.

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156

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Abstract. We developed two 150-MHz coherent radar depth sounders for ice thickness measurements over the Greenland ice sheet. We developed one of these using connectorized components and the other using radio frequency integrated circuits (RFICs). Both systems are designed to use pulse compression techniques and coherent integration to obtain the high sensitivity required to measure the thickness of more than 4 km of cold ice. We used these systems to collect radar data over the interior and margins of the ice sheet and several outlet glaciers. We operated both radar systems on the NASA P-3B aircraft equipped with GPS receivers. Radar data are tagged with GPS-derived location information and are collected in conjunction with laser altimeter measurements. We have reduced all data collected since 1993 and derived ice thickness along all flight lines flown in support of Program for Regional Climate Assessment (PARCA) investigations and the North Greenland Ice Core Project. Radar echograms and derived ice thickness data are placed on a server at the University of Kansas (http://tornado. rsl.ukans.edu/Greenlanddata.htm) for easy access by the scientific community. We obtained good ice thickness information with an accuracy of _+ 10 m over 90% of the flight lines flown as a part of the PARCA initiative. In this paper we provide a brief description of the system along with samples of data over the interior, along the 2000-m contour line in the south and from a few selected outlet glaciers. IntroductionIn 1991, NASA started a polar research initiative aimed at determining the mass balance of the Greenland ice sheet. This program consisted of coordinated surface, airborne, and spaceborne measurements for determining the mass balance of the ice sheet. The initial airborne program consisted of a laser altimeter and a Ku-band radar altimeter for measuring surface elevation of the ice sheet along selected flight lines. In 1993 the airborne instrumentation suite was expanded to include a radar depth sounder to collect ice thickness data along the same flight lines. Ice thickness is a key variable in the timedependent equation of continuity and is essential to any study of ice sheet dynamics.Raju et al.[1990] developed a coherent radar sounder for measurements in the Antarctic. We used this system to collect ice thickness data during the 1993 field season. Although the system collected good quality data in certain areas in the north and central parts of the ice sheet, its performance was less than optimum for obtaining ice thickness data over a few parts of the ice sheet in southern Greenland. These are in temperate areas of the ice sheet with thick, warm ice. To overcome its limitations and improve its performance, we developed two new systems: one using connectorized components and the other using radio frequency integrated circuits (RFICs). The transmitter and receiver prototypes for the system using RFICs were developed by senior undergraduate students as part of a capstone design project. We used these prototypes to devel...

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Section: System Descriptionmentioning

confidence: 99%

Coherent radar ice thickness measurements over the Greenland ice sheet

Gogineni¹,

Tammana²,

Braaten³

et al. 2001

J. Geophys. Res.

Self Cite

156

129

View full text Add to dashboard Cite

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“…The instrument used to acquire the data was a pulsecompression coherent radar mounted on a NASA P-3 aircraft and is described in detail by Gogineni et al [1998]. With a center frequency of 150 MHz and a 17 MHz bandwidth, the radar is capable of full penetration to the bedrock over most of the ice sheet area.…”

Section: Data Setmentioning

confidence: 99%

Internal layer tracing and age‐depth‐accumulation relationships for the northern Greenland ice sheet

Fahnestock¹,

Abdalati²,

Luo³

et al. 2001

J. Geophys. Res.

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Abstract. Clues to previous ice sheet structure and long-term glaciological processes are preserved in the internal layering configuration of the Greenland ice sheet. Information about these internal layers has been retrieved over many parts of the ice sheet with the University of Kansas ice-penetrating radar. We report on the coherence of these layers over very large distances, describe a method of tracing these layers along thousands of kilometers of flight line, and do so for one flight during the 1999 Program for Arctic Regional Climate Assessment (PARCA) aircraft campaign. We determine the ages of these layers, based on information at the GRIP ice core site, and extend these ages along the flight line to Camp Century, where they are compared to modeled-derived age estimates. These ages agree with each other to between 2 and 15%, differences that can be substantially reduced with minor changes to the model parameters (accumulation rate and shear layer depth). Finally, we are able to derive estimates of accumulation rates along the flight line by fitting the age-depth data from layer tracing to a Dansgaard-Johnsen model with a minimization technique, providing estimates that match recent accumulation patterns within a few centimeters per year.

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“…with the constant electromagnetic wave speed c ice = 168.5 m µs −1 (Gudmandsen, 1975;Peters et al, 2005;Winter et al, 2017) and a constant firn correction z f . In the DML region we use z f = 13 m, derived from the measurements of the complex permittivity of five ice cores, down to depths of 100-150 m .…”

Section: Internal Reflection Horizonsmentioning

confidence: 99%

“…RES measurements reveal deep internal reflection horizons (IRHs) that mainly originate from contrasts in conductivity. The conductivity signals (e.g., acid from volcanic eruptions) are deposited from the atmosphere and thus form isochronous horizons (Clough, 1977;Eisen et al, 2006;Fujita et al, 1999;Gogineni et al, 1998;Harrison, 1973;Jacobel and Hodge, 1995;Millar, 1981;Paren and Robin, 1975;Siegert et al, 1998b). We assign ages to isochronous IRHs from the age-depth scales of deep ice cores where the RES profiles pass close to the ice-core drill sites.…”

Section: Introductionmentioning

confidence: 99%

Age stratigraphy in the East Antarctic Ice Sheet inferred from radio-echo sounding horizons

Winter

Steinhage

Creyts

et al. 2019

Earth Syst. Sci. Data

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The East Antarctic Ice Sheet contains a wealth of information that can be extracted from its internal architecture such as distribution of age, past flow features, and surface and basal properties. Airborne radar surveys can sample this stratigraphic archive across broad areas. Here, we identify and trace key horizons across several radar surveys to obtain the stratigraphic information. We transfer the age-depth scales from ice cores to intersecting radar data. We then propagate these age scales across the ice sheet using the high fidelity continuity of the radar horizons. In Dronning Maud Land, including Dome Fuji, we mapped isochrones with ages of 38 and 74 ka. In the central region of East Antarctica around Dome Concordia, Vostok and Dome Argus, we use isochrone ages of 38, 48, 90 and 161 ka. Taking together both regions, we provide isochrone depths traced along a combined profile length of more than 40 000 km and discuss uncertainties of the obtained stratigraphy, as well as factors important to consider for further expansion. This data set is the most extensive distribution of internal horizons in East Antarctica to date. The isochrone depths presented in this study are available on PANGAEA (https://doi.org/10.1594/PANGAEA. 895528;Winter et al., 2018).

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An improved coherent radar depth sounder

Cited by 67 publications

References 74 publications

Coherent radar ice thickness measurements over the Greenland ice sheet

Coherent radar ice thickness measurements over the Greenland ice sheet

Internal layer tracing and age‐depth‐accumulation relationships for the northern Greenland ice sheet

Age stratigraphy in the East Antarctic Ice Sheet inferred from radio-echo sounding horizons

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