Data Set ID:

Annual Layers at Siple Dome, Antarctica, from Borehole Optical Stratigraphy, Version 1

Researchers gathered data on annual snow layers at Siple Dome, Antarctica, using borehole optical stratigraphy. This data set contains annual layer depths and firn optical brightness. The brightness log is a record of reflectivity of the firn, and peaks in brightness are interpreted to be fine-grained high-density winter snow, as part of the wind slab depth-hoar couplet.

Data are available via FTP in ASCII text (.txt) format

NSIDC does not archive these data.

  • Snow/Ice > Ice Depth/Thickness > ICE DEPTH/THICKNESS
  • Snow/Ice > Snow Depth > SNOW DEPTH
  • Snow/Ice > SNOW/ICE
  • Snow/Ice > Snow Stratigraphy > SNOW STRATIGRAPHY
Data Format(s):
Spatial Coverage:
N: -81.66, 
S: -81.66, 
E: -148.82, 
W: -148.82
Platform(s):Not specified
Spatial Resolution:Not SpecifiedSensor(s):Not specified
Temporal Coverage:
  • 15 December 2000 to 15 November 2001
Temporal ResolutionNot specifiedMetadata XML:View Metadata Record
Data Contributor(s):Edwin Waddington, Robert Hawley, Richard Alley, Kendrick Taylor

Geographic Coverage

Please contact the data provider for the correct Data Citation for this data set.

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This data set contains optical brightness and depth data from the Siple Dome borehole in Antarctica, as well as layer depths derived from the brightness log. These data can provide insight into firn compaction and vertical motion of the ice sheet.

Detailed Data Description


The data set is provided as two ASCII text (.txt) files.

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File and Directory Structure

The data set consists of two data files, layers.txt and BOS.txt. Data are on the FTP site in the folder.

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File Size

Two data files are 12 KB to 467 KB.

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The entire data set is approximately 480 KB.

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Spatial Coverage

Siple Dome, Antarctica
Latitude: 81.66° S
Longitude: 148.82° W

Spatial Resolution

5 mm depth

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Temporal Coverage

15 December 2000 to 15 November 2010, Austral summer only

Temporal Resolution

Single measurement

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Parameter or Variable

This data set provides annual layer depths and firn optical brightness, as measured by Borehole Optical Stratigraphy (BOS). These data include both the optical brightness versus depth record from Siple Dome, and also the layer depths derived from the brightness log. The brightness log is a record of firn reflectivity, and peaks in brightness are interpreted to be fine-grained high-density winter snow, as part of the "wind slab depth-hoar couplet." For more details see Hawley, et. al., 2003.

Parameter Description

The data set consists of two files. Layer picks are provided as one single column in the layers.txt file. The file BOS.txt provides depth and brightness measurements made using Borehole Optical Stratigraphy (BOS), a method described in detail in Hawley, et. al., 2003.

Table 1. Parameter Description for the BOS.txt file
Parameter Description
Depth Depth in meters
Intensity Optical brightness, measured using the BOS method.
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Software and Tools

Software and Tools

Data are readable using standard spreadsheet software.

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Data Acquisition and Processing

Data Acquisition Methods

Data were collected using Borehole Optical Stratigraphy (BOS). BOS uses a downward looking video camera and post-processing software to create a log of brightness versus depth. The active light source on the camera returns from the borehole walls to the camera, which views the walls with a wide angle lens. Brightness is calculated by averaging the pixel values of an annulus of pixels around the borehole wall. For a detailed description of techniques, see Hawley, et. al., 2003 and Hawley, et. al., 2011.

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References and Related Publications

Contacts and Acknowledgments

Dr. Edwin D. Waddington
University of Washington 
Department of Earth and Space Sciences
Seattle, Washington 98195-1310

Dr. Robert L. Hawley
Dartmouth College
Earth Sciences, HB 6105
Hanover, New Hampshire 13755

Dr. Richard B. Alley
Department of Geosciences 
517 Deike Building 
University Park, Pennsylvania 16802 

Dr. Ken C. Taylor
Desert Research Institute
Department of Geosciences 
Nevada System of Higher Education
2215 Raggio Parkway 
Reno, Nevada 89512


This research was supported by the National Science Foundation (NSF) Office of Polar Programs (OPP) grant number 0087521.

Document Information

Document Creation Date

April 4, 2012

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