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Data Set ID:
NSIDC-0274

Compilation of Antarctic Radar Data, Siple Coast, 2000-2002, Version 1

These data consist of ground-based, ice-penetrating radar profiles across satellite-detected lineations and terrains that were taken in the lower reaches of Ross Ice Stream C, also known as the Kamb Ice Stream (KIS); on Roosevelt Island; on the Siple Dome; and on the Shabtaie Ice Ridge.

Geographic Coverage

Spatial Coverage:
  • N: -81, S: -84, E: -134, W: -158

Spatial Resolution: Not Specified
Temporal Coverage:
  • 3 January 2002 to 28 January 2002
  • 11 November 2000 to 7 December 2000
Temporal Resolution: Not specified
Parameter(s):
  • Glaciers/Ice Sheets > Glacier Motion/Ice Sheet Motion
  • Sea Ice > Ice Floes
  • Glaciers/Ice Sheets > Ice Sheets
  • Snow/Ice > Snow Stratigraphy
Platform(s) GROUND-BASED OBSERVATIONS
Sensor(s): GPR
Data Format(s):
  • Binary
  • JPEG
Version: V1
Data Contributor(s): Charles Raymond, Howard Conway, Ginny Catania

Data Citation

As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

Raymond, C., H. Conway, and G. Catania. 2005. Compilation of Antarctic Radar Data, Siple Coast, 2000-2002, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: http://dx.doi.org/10.7265/N5736NTS. [Date Accessed].

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Detailed Data Description

These data consist of ground-based, ice-penetrating radar profiles across satellite-detected lineations and terrains that were taken in the lower reaches of Ross Ice Stream C, also known as the Kamb Ice Stream (KIS); on Roosevelt Island; on the Siple Dome; and on the Shabtaie Ice Ridge. Researchers collected low frequency (2 MHz - 7 MHz) data during two separate deployments, 11 November through 7 December 2000 and 3 January through 28 January 2002. These radar data provide information on surface morphology and internal layer stratigraphy. The data are in the form of raw binary data files, accompanied by processed data files in JPEG format.

These data are from a study of the scar-like features that are well known from the Siple Coast ice stream system in West Antarctica. The objective of the field work was to identify the nature of several scars, and to further characterize previously-identified margin scars that have been poorly dated. Advanced Very High Resolution Radiometer (AVHRR) and Radarsat image data, which are not included in this data set, were used to locate and map the features, and place them in a regional context. The study describes the recent history of the Siple Coast glaciers and investigates the causes of their changes in configuration. The main investigative tools were ground penetrating radar (GPR) profiles used to image internal layers and measure the depths to buried crevasses or disrupted layering. This, coupled with accumulation rates determined from shallow ice cores, provides "shutdown" ages for the margin features. The field data provide input parameters for simple models of ice flow for margins and inter-ice stream ridges during active shearing and after shutdown. Such modeling will output an estimate of the initial elevation of scars and the corresponding ice stream elevation at the time of shutdown.

Format

The processed data are JPEG image files. Raw data are DAT binary files.

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Directory Structure and File Naming Conventions

The image files are coded by location. The north side of Kamb Ice Stream (KIS) includes an area called "Duckfoot," named for the splayed pattern of lineations that mark its surface. A similar area exists on the south side of KIS called "Goosefoot." The two regions consist of several different types of ice terrains, each with distinct characteristics.

Table 1. List of Variables Used in File Names
Variables Description
Duck Duckfoot location
BC Engelhardt Ice Ridge formerly known as Ice Ridge BC
UPBC "up BC," the upper reaches of the Engelhardt Ice Ridge
DNBC "down BC," the lower reaches of the Engelhardt Ice Ridge
GLBC the "grounding line" of the Engelhardt Ice Ridge
Bumps the "Bumps line" of the Engelhardt Ice Ridge

See the Study Area Location section to view site names and locations. The profile names provided in the Spatial Coverage section correspond to the file names of the JPEG images.

Raw data file names follow the convention YYDDDnn, where YY is the year (00 or 01), DDD is the Julian day (001, 002...365), and nn is the file number for that day (01, 02...21).

metadata directory:

  • metadata.doc (5.61 MB)
  • metadata.pdf (5.17 MB)

processed_data directory: This directory contains rendered images of the raw data.

  • sis.jpg (312 KB)

Duckfoot subdirectory:

  • D_Duck.jpg (383 KB)
  • U_Duck.jpg (271 KB)
  • C_Duck.jpg (226 KB)
  • K_Duck.jpg (318 KB)

Goosefoot subdirectory:

  • A_DNBC.jpg (259 KB)
  • B_DNBC.jpg (370 KB)
  • E_GLBC.jpeg (319 KB)
  • F_GLBC.jpg (397 KB)
  • G_GLBC.jpeg (291 KB)
  • O_GLBC.jpeg (348 KB)
  • S_GLBC.jpg (323 KB)

up_ER subdirectory:

  • B_UPBC.jpg (274 KB)
  • Bumps.jpg (269 KB)
  • C_UPBC.jpg (294 KB)

raw_data directory:

This directory contains the raw binary data files containing the radar profile data. The file sizes range from 24 KB to 1.61 MB.

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File Size

Raw data files range from 16 KB to 1.61 MB. The processed JPEG image files range from 226 KB to 397 KB.

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Study Area Location

Refer to Figure 1 for a map of the study location. Click on the thumb nail for full image.

Figure 1. Compilation of Antarctic Radar Data, Siple Coast, 2000-2002
Figure 1. Compilation of Antarctic Radar Data, Siple Coast, 2000-2002

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Spatial Coverage

Southernmost Latitude: 84° S
Northernmost Latitude: 81° S
Westernmost Longitude: 158° W
Easternmost Longitude: 134° W

Below is a table of information including the profile name, start waypoint, end waypoint, raw data file name, and the radar frequency.

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Temporal Coverage

Data were collected between 11 November and 7 December 2000 and between 3 January and 28 January 2002.

Temporal Resolution

Low frequency data were collected from the range of 2 MHz to 7 MHz.

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Parameter or Variable

Parameter Description

These radar data provide information on surface morphology and internal layer stratigraphy of the Kamb Ice Stream (KIS).

Sample Data Image

Figure 2. Compilation of Antarctic Radar Data, Siple Coast, 2000-2002
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Error Sources

Error in the measurements arises from three main sources:

  • the migration technique (Refer to the Processing Steps section.)
  • uncertainty picking the location of the bed reflection
  • uncertainty in the radio wave velocity within the glacier.

For these measurements the investigators estimate the uncertainty in ice thickness to be approximately 5 m.

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Software and Tools

The processed radar images are in JPEG format and are viewable with most image viewing software. The binary files can be viewed using MATLAB.

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Volume

The entire data set is approximately 74.2 MB.

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Data Acquisition and Processing

Data Acquisition Methods

Short-pulse radar systems were used to image deep internal layers, 100 m to 1,000 m. Investigators used a pressure transducer and a geodetic-quality global positioning system (GPS) receiver to measure surface topography and elevations.

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Processing Steps

Interpreting isolated spot measurements of the amplitude and two-way travel time of reflections can be problematic, so investigators made a profile of contiguous measurements that were typically spaced approximately 10 m apart. For each profile image, all records were first band-pass filtered. In cases where the amplitude of the surface topography is on the order of the ice thickness, it was necessary to adjust the records for surface elevation before migrating the data. Two-way travel time was converted to ice thickness by correcting for geometry and assuming a wave speed of 168 m/µs in ice.

See Processing Radar Data with MATLAB.

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Sensor or Instrument Description

The University of Washington radar system is based on a design described by Watts and Wright (1981). The transmitter used for these measurements is a lightweight (<0.25 kg) mono-pulse unit described by Jones et al. (1989). A Tektronix digital oscilloscope is used to record the two-way travel time and amplitude of reflections from within the ice. The internal stacking capacity of this oscilloscope is limited to 10,000 records, but waveforms are recorded with an average of 500 stacks. Power for the transmitter, oscilloscope, and computer was supplied by separate 12V, 100 ampere-hour batteries. Investigators used weighted dipole antennae ( f=300 W ) (Watts & Wright, 1981), threaded inside climbing webbing for protection, with center frequencies of 2 MHz and 5 MHz. One and a half full dipole antennae lengths separated the transmitter and receiver.

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References and Related Publications

Contacts and Acknowledgments

Howard Conway
University of Washington
1100 NE 45th St, Suite 300
Seattle, WA 98195

Charles Raymond
Geophysics Program
Box 351650
University of Washington
Seattle, WA 98195-1650

Ginny Catania 
Institute for Geophysics
4412 Spicewood Springs Rd., Unit 600
University of Texas
Austin, TX 78759

Acknowledgements: 

This research was supported by the NSF grant OPP- 9909518, Office of Polar Programs award to Charles Raymond and Howard Conway.

The investigators would like to thank Maurice Conway and Tony Gades for their assistance in the field.

Document Information

DOCUMENT CREATION DATE

February 2006

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