Data Set ID:

Digital Imaging for Siple Dome Ice Core Analysis, Antarctica, Version 1

This data set contains high-resolution digital images of thin and thick sections cut from the 1003 meter Siple Dome A main ice core. The images are useful for crystal size and orientation analysis and bubble size, shape, distribution, and number density determinations. The data set contains several generations of images, taken between June 1998 and May 2005. An accompanying spreadsheet contains creation date information for each file.

The data are available via FTP in Adobe Photoshop Document (.psd), and Tagged Image File (.tif) formats. Additional information is provided as a Microsoft Excel (.xls) spreadsheet.

NSIDC does not archive these data.

  • Ice Core Records > Ice Core Air Bubbles > ICE CORE AIR BUBBLES
  • Ice Core Records > ICE CORE RECORDS
  • Visible Wavelengths > Visible Imagery > VISIBLE IMAGERY
Data Format(s):
  • TIFF
  • PSD
Spatial Coverage:
N: -80.666667, 
S: -80.666667, 
E: -148.816667, 
W: -148.816667
Platform(s):Not specified
Spatial Resolution:Not SpecifiedSensor(s):Not specified
Temporal Coverage:
  • 1 June 1998 to 30 May 2005
Temporal ResolutionNot specifiedMetadata XML:View Metadata Record
Data Contributor(s):Richard Alley, Joan Fitzpatrick, Matthew Spencer

Geographic Coverage

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

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Detailed Data Description


Data are available in Adobe Photoshop Document (.psd), and Tagged Image File (.tif) formats. The SDMA_file_creation_dates.xls spreadsheet contains detailed information about each image file, including the date the photo was acquired, the image resolution in pixels per inch (ppi), and the stratigraphic image orientation.

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File and Directory Structure

Data are available on the FTP site in the directory. Within this directory, there SDMA_psd directory contains the data set in .psd format. The SDMA_tif directory contains all the ice core images as .tif files. The directory also contains a readme file in .txt format, and a Microsoft Excel spreadsheet with creation date information.

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File Naming Convention

Files are named according to the following convention and as described in Table 1:



Table 1. File Naming Convention
Variable Description
SDMA Siple Dome "A" Ice Core
ddd-ddd Depth of sample, in meters. The dash corresponds to a decimal point.
For example, 240-123 corresponds to 240.123 meters
ttt Type of section:
  • HB: Horizontal Bubble Section
  • VB: Vertical Bubble Section
  • HTS: Horizontal Thin Section
  • VTS: Vertical Thin Section
N Sequence number: Presence of a sequence number indicates that the same ice core section was photographed multiple times under slightly different magnification or rotation. Absence of a sequence number means that the photograph is unique.
.bin File extension: .tif or .psd

Example: SDMA240-123VTS1 is first in a series of vertical thin section images, from the section at 240.123 meters of the Siple Dome A ice core.

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File Size

Files range in size from 490 KB to 20550 KB.

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The data set is a total of 1.42 GB.

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Spatial Coverage

Photographs are from sections of the 1003-meter deep main ice core from Siple Dome A. The core drilling was completed in 1999.

Southernmost Latitude: 81°40'S
Northernmost Latitude: 81°40'S
Westernmost Longitude: 148°49'W
Easternmost Longitude: 148°49'W

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Temporal Coverage

The ice core drilling was completed in 1999. Photographs were taken between June 1998 and September 1999.

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Parameter or Variable

This data set contains high-resolution digital images of ice core sections from the Siple Dome A ice core.The data set includes thin and thick (bubble) sections, cut both vertically and horizontally. Depth of the images range from 153 meters to 936 meters deep. The ice core was 1003 meters deep. Each image includes a ruler for size reference.

Sample Data Records

sample image of an bubble ice core section
Sample Horizontal Bubble Ice Core Section (SDMA153-5HBa.tif)
vertical section sample image
Sample Horizontal Thin Ice Core Section (SDMA153-5HTS.tif)
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Quality Asessment

The data set contains several generations of images. The best images are those acquired on sections cut in the field during drilling operations (completed in January, 1999). These sections were completed in the field to a nominal depth of 560 meters although the final total depth of the core was 1003 meters. Below 560 meters ice became too brittle to handle without incurring significant damage and no further attempt to cut it in the field was made.

Later efforts at cutting additional sections to complete analyses to the bottom of the core continued to be challenging due to the failure of the core to significantly relax during the intervening years. The extraordinary mechanical fragility of this core remains a physical hallmark even ten years after its recovery. A high percentage of bubbles in the core opened stress-relief cracks, complicating the size analysis (though not the number of density determinations). These annular cracks are apparent in the bubble section photographs taken below 400 meters in the year 2000 and later, as are large, through-going cracks created while cutting the sections from the main body of the core after it was returned from Antarctica to the National Ice Core Laboratory in Denver, Colorado, USA.

Image Quality Comparison

bubble comparison image
Comparison of Image Quality in Ice Core Bubble Images
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Software and Tools

Data are available via FTP.

Software and Tools

Data are accessible using image processing software.

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Data Acquisition and Processing

Theory of Measurements

Thick (bubble) sections were photographed in 90 degree darkfield illumination using a circular light source at the level of the section. Thin sections (grain analysis) were photographed in cross-polarized, transmitted light. A high-resolution scanning digital camera was utilized for all photography.

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References and Related Publications

Contacts and Acknowledgments

Dr. Joan Fitzpatrick
MS-980 Box 25046, DFC
United States Geological Survey
Denver, CO 80225

Dr. Richard B. Alley
Department of Geosciences
306 Deike Building
Pennsylvania State University
University Park, PA 16802 

Dr. Matthew Spencer
Department of Geology and Physics
Lake Superior State University
650 W. Easterday Ave. 
Sault Ste. Marie, MI 49783


This research was supported by National Science Foundation (NSF) Office of Polar Programs (OPP) grant 9615554 and the U.S. Geological Survey Earth Surface Dynamics Program.

Document Information


10 August 2009

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