Systems for Measuring Thickness of Temperate and Polar Ice from the Ground or from the Air

Watts, Raymond D.; Wright, David L.

doi:10.1017/s0022143000011485

Cited by 65 publications

(49 citation statements)

References 5 publications

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“…A thorough treatment of a similar system has been published (Watts and Wright, 1981), so only a basic outline of the instrument circuitry is provided, except where differences merit detail.…”

Section: Applicationmentioning

confidence: 99%

Ice Volumes on Cascade Volcanoes: Mount Rainier, Mount Hood, Three Sisters, and Mount Shasta

Driedger¹,

Kennard²

1986

Professional Paper

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Path of light Resistance per unit length Time between arrivals of air and reflected waves on the oscilloscope Volume Volume estimation by calculation of basal shear stress Distance from antenna feedpoint in meters Slope of ice measured from horizontal Antenna half-length (meters) Refractive index of ice Frequency Density of ice Basal shear stress Estimated basal shear stress Resistive loading constant (ohms)

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Section: Applicationmentioning

confidence: 99%

Ice Volumes on Cascade Volcanoes: Mount Rainier, Mount Hood, Three Sisters, and Mount Shasta

Driedger¹,

Kennard²

1986

Professional Paper

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“…While there has been some success sounding these critical areas with VHF radars, the performance of radars operating above 50 MHz degrades over the temperate ice within fast-flowing glaciers [37][38][39]. Sounding of these areas suggests the need for lower frequency radars that are inherently less sensitive to scattering features and extinction in the wet ice.…”

Section: Introductionmentioning

confidence: 99%

HF/VHF Radar Sounding of Ice from Manned and Unmanned Airborne Platforms

et al. 2018

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Ice thickness and bed topography of fast-flowing outlet glaciers are large sources of uncertainty for the current ice sheet models used to predict future contributions to sea-level rise. Due to a lack of coverage and difficulty in sounding and imaging with ice-penetrating radars, these regions remain poorly constrained in models. Increases in off-nadir scattering due to the highly crevassed surfaces, volumetric scattering (due to debris and/or pockets of liquid water), and signal attenuation (due to warmer ice near the bottom) are all impediments in detecting bed-echoes. A set of high-frequency (HF)/very high-frequency (VHF) radars operating at 14 MHz and 30-35 MHz were developed at the University of Kansas to sound temperate ice and outlet glaciers. We have deployed these radars on a small unmanned aircraft system (UAS) and a DHC-6 Twin Otter. For both installations, the system utilized a dipole antenna oriented in the cross-track direction, providing some performance advantages over other temperate ice sounders operating at lower frequencies. In this paper, we describe the platform-sensor systems, field operations, data-processing techniques, and preliminary results. We also compare our results with data from other ice-sounding radars that operate at frequencies both above (Center for Remote Sensing of Ice Sheets (CReSIS) Multichannel Coherent Depth Sounder (MCoRDS)) and below (Jet Propulsion Laboratory (JPL) Warm Ice Sounding Explorer (WISE)) our HF/VHF system. During field campaigns, both unmanned and manned platforms flew closely spaced parallel and repeat flight lines. We examine these data sets to determine image coherency between flight lines and discuss the feasibility of forming 2D synthetic apertures by using such a mission approach.

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“…Subsequent improvements to impulse radars have concentrated on increasing the transmitted power, modifying the system for airborne surveys and triggering the transmitter, so that it could be synchronized with a sampler or digitizer. Triggered transmitters have evolved along two lines: those based on avalanche transistors (Watts and Wright, 1981;Wright and others, 1990) and those based on thyristors (Sverrisson and others, 1980;Walford and others, 1986;lones, 1987;lones and others, 1989). In this paper, we describe a new transmitter based on avalanche transistors.…”

Section: Introductionmentioning

confidence: 99%

Miniature high-power impulse transmitter for radio-echo sounding

Narod

Clarke

1994

J. Glaciol.

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We have developed a miniature high-power impulse transmitter for radio-echo sounding of glaciers. It features two synchronous second break-down pulse generators operating in a differential configuration. Specifications include bipolar 550 V pulses having rise times less than 2 ns, 512 Hz repetition rate, 180 mA at 10-14 V d.c. operating power, 5 mA standby current and maximum dimension of 12 cm. Because of its small size and low power consumption, the transmitter is suitable for back-portable systems and for towed arrays. The transmitter first saw service in 1990 on Trapridge Glacier, Yukon Territory. Subsequent copies have been used on Agassiz Ice Cap, Northwest Territories, Bering Glacier, Alaska and elsewhere. To date, the maximum ice thickness measured using this transmitter is 825 m, on temperate Bering Glacier.

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Systems for Measuring Thickness of Temperate and Polar Ice from the Ground or from the Air

Cited by 65 publications

References 5 publications

Ice Volumes on Cascade Volcanoes: Mount Rainier, Mount Hood, Three Sisters, and Mount Shasta

Ice Volumes on Cascade Volcanoes: Mount Rainier, Mount Hood, Three Sisters, and Mount Shasta

HF/VHF Radar Sounding of Ice from Manned and Unmanned Airborne Platforms

Miniature high-power impulse transmitter for radio-echo sounding

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