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Data Set ID:
NSIDC-0303

Radar Investigations of Antarctic Ice Stream Margins, Siple Dome, 1998, Version 1

This data set consists of surface-based radar measurements, including geometry of the bed, surface, and internal layers, and bed reflectivity measurements at two sites along ice stream margins at Siple Dome, Antarctica. The research is a radar examination of bed reflection characteristics and internal layer geometry in two inter-ice-stream ridges, the Shabtaie Ridge (Ridge D/E) and the Engelhardt Ridge (Ridge B/C), and across margins with the adjacent ice streams, the MacAyeal Ice Stream (Ice Stream E) and the Whillans Ice Stream (Ice Stream B). Investigators collected these radar data from 14 November through 13 December 1998.

Data are in Microsoft Word, PDF, ASCII text, MATLAB, binary, and various image formats. Investigators have also provided code for MATLAB routines that they used to view the radar data. Data are available via FTP.

Geographic Coverage

Spatial Coverage:
  • N: -80.1678, S: -83.3528, E: -138.3697, W: -141.6722

Spatial Resolution: Not Specified
Temporal Coverage:
  • 14 November 1998 to 13 December 1998
Temporal Resolution: Not specified
Parameter(s):
  • Radar > Radar Reflectivity > Bed Reflectivity
  • Radar > Radar Imagery > Bed
  • Surface
  • and Internal Layer Geometry
Platform(s) GPS, GROUND-BASED OBSERVATIONS
Sensor(s): GPR, GPS RECEIVERS
Data Format(s):
  • MATLAB
  • Microsoft Word
  • PDF
  • Binary
  • ASCII Text
Version: V1
Data Contributor(s): Nadine Nereson, Charles Raymond

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.

Nereson, N. A. and C. Raymond. 2007. Radar Investigations of Antarctic Ice Stream Margins, Siple Dome, 1998, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: http://dx.doi.org/10.7265/N52B8VZP. [Date Accessed].

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Detailed Data Description

Format
Format/Type Extensions
Portable Document Format .pdf
Microsoft Word .doc
ASCII text .txt, .log, .dat
MATLAB data and code .m, .mat
Radar data .dsf, .rad, .rd3
C code .c
Paint Shop profile .psc
Binary field data .fld, .bas
Corel Draw file .cor
PostScript files .ps, .psf, .epsi
Island Draw file .idr
Executable files .exe

See Software and Tools for information on available data viewing software.

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File and Directory Structure

The following table describes the structure of the higher level data directories only. See investigator-provided documentation Radar Investigations of Ice Stream Margins: Digital Data.

Directory
/Subdirectory
File Name Description
Ridges_Data_Explanation.doc Investigator-provided overview of the data product, Radar Investigations of Ice Stream Margins: Digital Data
DATA_REPORT

datareport.pdf Investigator-provided report titled Radar Investigations of Ice Stream Margins: Data Report by Nadine Nereson and Charles Raymond in PDF
datareport.ps Report in postscript format
/Figures High resolution PS images of all radio echo sounding profiles
GPR
/bmargin GPR data from the Whillans Ice Stream (Ice Stream B) margin
/emargin GPR data from the MacAyeal Ice Stream (Ice Stream E) margin
/sdm GPR data from the Siple Dome
METHODS
RESDataAnalysisHowTo.pdf Investigator-provided how-to documentation describing data reduction methods
/CODE Routines for converting raw binary data from the recording system to MATLAB-readable files and basic MATLAB script for a variety of purposes
RIDGE_BC_1998
/data Raw data and MATLAB files (.mat)
/docs Field log to explain the raw data and other documentation

See RidgeBC-Files.pdf for an investigator-provided description of the RIDGE_BC_1998 subdirectory.
/GPS Static and kinematic processed GPS data from the cross-dome profiles
/matlab_scripts MATLAB script files to load and plot the data
/plots Postscript versions of the plots and also the associated MATLAB files (.m and .mat) that can be used to automatically regenerate the plot
/RBC_LayerModel Layer model files
/satellite_images Annotated AVHRR images that show the ridges, ice streams, and the radar profiles
RIDGE_DE_1998
/data Raw data and MATLAB files (.mat) and data measured by Garmin GPS receivers
/docs Field logs to explain the raw data and other documentation

See RidgeDE-Files.pdf for an investigator-provided description of the RIDGE_DE_1998 subdirectory.
/GPS Static and kinematic processed GPS data from the cross-dome profiles
/Layer_Model Layer model files
/matlab_scripts MATLAB script files to load and plot the data
/plots Postscript versions of the plots and also the associated MATLAB files (.m and .mat) that can be used to automatically regenerate the plot
/satellite_images Annotated AVHRR images that show the ridges, ice streams, and the radar profiles
 
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Volume

The entire data set is 519 MB.

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Spatial Coverage

Southernmost Latitude: 83.3528° S 
Northernmost Latitude: 80.1678° S
Westernmost Longitude: 141.6722° W
Easternmost Longitude: 138.3697° W

Elevation Range: 322.703 m - 560.816 m

Spatial Resolution

Investigators collected radar data every 5 meters for profiles across the ice steam shear margins and approximately every 30 meters for profiles on the inter-ice-stream ridges.

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Temporal Coverage

Investigators collected data from 14 November through 13 December 1998.

Temporal Resolution

Investigators collected radar data at 2 MHz.

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Parameter or Variable

Investigators examined bed reflection and internal layer geometry by collecting GPR data. They also collected supplementary differential GPS data.

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Software and Tools

MATLAB, IDL, ENVI, XV, Ghostview, and ImageMagick are some of the possible tools for viewing the radar data. Investigators have provided the codes used to view the data in MATLAB. Visit GPR IDL Tools for more information on viewing radar data with IDL software tools.

Visit MALA GeoScience, which is the manufacturer of the radar system that the investigators used, for information on additional software available for viewing the radar data.

Quality Assessment

Because the airwave signal swamps the first 1 µs of the data record, the first step in data processing is to remove the mean waveform from the profile to remove the airwave effect and reveal shallow layer information in the first 1 µs. Since the GPS data have not been fully processed, absolute error in vertical elevation could be as large as 50 m, so the displayed elevation scales for the radar profiles should be considered approximate. The profiles displayed in images are based on data files that have been subjected to demeaning and filtering and would therefore not be appropriate for any analyses directed toward accurate assessment of amplitude and phase without careful consideration.

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Data Acquisition and Processing

Instrument Description and Acquisition Methods

This data set includes radar profiles from within the ice and its base and surface elevation profiles. Investigators collected radar data every 5 meters for profiles across the ice stream shear margins and approximately every 20 meters for profiles on the inter-ice stream ridges using 2 MHz antennae. The recording system was centered on a Tektonix TDS410 digital oscilloscope. Investigators used Garmin GPS100 SRVYII receivers to report differential GPS data.

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Derivation Techniques and Algorithms

An overview of the methods that the investigators used to collect and reduce the data is available on the University of Washington's Glaciology Group Web site, http://www.geophys.washington.edu/Surface/Glaciology/PROJECTS/radar/. A copy of this documentation, RESDataAnalysisHowTo.pdf, is provided with the data in the METHODS directory. Routines for converting the raw binary data from the recording system to MATLAB-readable files and other miscellaneous MATLAB scripts are provided in the CODE subdirectory of the METHODS directory.

Processing Steps

Detailed processing information can be found in the investigator-provided documentation, datareport.pdf, that is included with the data.

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References and Related Publications

Contacts and Acknowledgments

Nadine A. Nereson
Department of Earth and Space Sciences
Box 35130
University of Washington
Seattle, WA 98195-1310 USA

Charles F. Raymond
Department of Earth and Space Sciences
Box 35130
University of Washington
Seattle, WA 98195-1310 USA

Acknowledgements: 

This research was funded by the National Science Foundation (NSF) Office of Polar Programs (OPP) grant 9725882 awarded to Charles Raymond.

Document Information

Document Creation Date

July 2007

No technical references available for this data set.
No FAQs or How Tos available for this data set.

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