WAIS Divide Ice Core Images, Antarctica

Summary

This data set is comprised of optical images of ice core sections, acquired with a digital line-scan camera in the cold room facility at the U.S. National Ice Core Laboratory (NICL). Ice core sections are archival cuts which have rough-out rounds of ice with a single plane cut along one side. Ice sections were illuminated with fiber optic light guides connected to a 1000 watt (W) xenon light source. Original scan resolution varies from about 0.05 mm to 0.1 mm, and is documented in the metadata for each image. Images are in uncompressed Tagged Image File (.tif) form, with resolutions of 1.0 mm and 0.1 mm. Depth of image in the ice core is documented in the metadata files for each image.

Data are available via FTP as .tif image files. Supporting information is available as ASCII text files (.txt), and other file formats readable with a freely available image processing program, IceImageJ.

Citing These Data

The following example shows how to cite the use of this data set in a publication. For more information, see our Use and Copyright Web page.

The following example shows how to cite the use of this data set in a publication. List the principal investigators, year of data set release, data set title, publisher: NSIDC, and digital media

McGwire, K. 2009. WAIS Divide Ice Core Images, Antarctica. Boulder, Colorado, USA: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N5348H8T.

Overview Table

Category	Description
Data format	Data are available in Tagged Image File (.tif) format. Metadata are available as ASCII text files (.txt). Supporting information for image files is available in Report Object Instance (.roi), Audio Interchange File Format (.aiff), and Pro Tools Session (.pts) formats, readable by freely available image processing software, IceImageJ.
Spatial coverage and resolution	Southernmost Latitude: 79°29.058'S Northernmost Latitude: 79°29.058'S Westernmost Longitude: 112°05.189'W Easternmost Longitude: 112°05.189' W
Temporal coverage and resolution	2006 to 2007
File naming convention	WDC06A-1-1-1.0mm.tif WDC06A-1-1-1.0mm.txt
File size	Files in this data set range in size from 4 KB to about 1 MB.
Parameter(s)	Ice core images
Procedures for obtaining data	Data are available via FTP.

Table of Contents

1. Contacts and Acknowledgments
2. Detailed Data Description
3. Data Access and Tools
4. Data Acquisition and Processing
5. References and Related Publications
6. Document Information

1. Contacts and Acknowledgments

Investigator(s)

Dr. Ken McGwire
Desert Research Institute
School of Engineering
PO Box 2039
Merced, California 95344

Technical Contact

Acknowledgements

This research was supported by NSF OPP grants 0637004, 0230149, and 0440817.

2. Detailed Data Description

Format

Data are available as Tagged Image File (.tif) image files. Metadata for each image is available in an ASCII text (.txt) file. Supporting information for image files is available in Report Object Instance (.roi), Audio Interchange File Format (.aiff), and Pro Tools Session (.pts) formats, readable by freely available image processing software, IceImageJ.

File and Directory Structure

Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/AGDC/mcgwire_nsidc_0375/ directory. The data are in two folders, which correspond to the image resolution (1.0 mm and 0.1 mm). The directory also contains a readme file in ASCII text format.

Within each folder, numbered folders correspond to the scan number, 001 to 577. Each numbered file contains two folders, names PD_1.10 and ScanFiles. The PD_1.10 folder contains .tif image files, and a text file corresponding to each image file. The ScanFiles folder contains ancillary information acquired during the ice core scan, which can be read by IceImageJ software, which is freely available. For more information, or to download the image processing software, visit the Desert Research Institute Department of Earth and Ecosystem Sciences Web site.

Figure 1. Directory Structure on the FTP Site

File Naming Convention

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

WDC06A-x-x-ymm.zzz

Where:

Table 1. File Naming Convention

Variable	Description
WDC06A	Ice core identification
-x-x-	Scan number
ymm	Image resolution, in milimeters
.zzz	File extension

File Extensions

The data set also contains image information, in .roi, .pts, and .aiff formats, that can be read using IceImageJ, freely available image processing software. IceImageJ and additional information are available from the Desert Research Institute Department of Earth and Ecosystem Sciences Web site. Table 2 describes the information contained in the various file formats.

Table 2. File Extension Descriptions

Extension	File Contents
.tif	Ice core image
.txt	In PD_1.10 folder: metadata for .tif ice core image In ScanFiles folder: metadata for original ice core scan
.roi	Mask indicating areas of ice image that are background or where ice is fractured
.pts	Location of points automatically identified on a calibration target
.aiff	Audio file with comments the scanning personnel may have made during scan

File Size

Files in this data set range in size from 4 KB to about 1 MB.

Spatial Coverage

This data set contains images of ice core sections from the West Antarctic Ice Sheet Divide ice core WDC06A.

Southernmost Latitude: 79°29.058'S
Northernmost Latitude: 79°29.058'S
Westernmost Longitude: 112°05.189'W
Easternmost Longitude: 112°05.189' W

Spatial Coverage Map

Figure 2. Location Map

Temporal Coverage

Ice core images in this collection were scanned in 2006 and 2007.

Parameter or Variable

This data set contains optical ice core images in .tif file format. Supporting files for each image, in ASCII text format, provide detailed information on scan resolution, depth of ice core image, and camera settings. Additional files provide information readable by the IceImageJ image processing software. For more information or to download the IceImageJ software, visit the Desert Research Institute Department of Earth and Ecosystem Sciences Web site.

Sample Data Record

The following examples show a sample data image, WDC06A-2-1-1.0mm.tif. Scan information for this file is available in the text file, WDC06A-2-1-1.0mm.txt.

Figure 3. Sample Data Image

3. Data Access and Tools

Data Access

Data are available via FTP.

Volume

The total volume of the data set is about 16 GB.

Software and Tools

Data are accessible using image processing software. IceImageJ software is a modification to the java-based ImageJ program that was developed for the National Institutes of Health by Wayne Rasband. ImageJ is available from the National Institutes of Health. The IceImageJ modification and additional information are available from the Desert Research Institute Department of Earth and Ecosystem Sciences Web site.

Related Data Collections

• Antarctic Glaciological Data Center (AGDC)

4. Data Acquisition and Processing

Sensor or Instrument Description

Images were collected with a digital line-scan camera during the core processing line at the U.S. National Ice Core Laboratory.

Data Acquisition Methods

Images were sidelit on both sides with fiberoptic paddles. Ice sections were cut and planed on the side that is imaged and left as a 'rough-out' half-round on the backside. Original images were scanned at varying resolution, but generally finer than 0.1 mm. Data products in this dataset have been low-pass filtered with a windowed sinc filter with a full-width half-maximum of 1.0 mm and resampled to a 1.0 mm resolution in both dimensions.

5. References and Related Publications

McGwire, K. C., G. M. Hargreaves, R. B. Alley, T. J. Popp, D. B. Reusch, M. K. Spencer, and K. C. Taylor. 2008. An Integrated System for Optical Imaging of Ice Cores. Cold Regions Science and Technology, Volume 53, Issue 2, Pages 216-228.

McGwire, K.C., J.R. McConnell, R.B. Alley, J.R. Banta, G.M. Hargreaves, and K.C. Taylor. 2008. Dating Annual Layers of a Shallow Antarctic Ice Core with an Optical Scanner. Journal of Glaciology, 54(188):831-838.

The following related documents are available online:

Table 3. Related Documents

Document	Description	URL
Antarctic Glaciological Data Center (AGDC)	Project Web site	http://nsidc.org/agdc/
Division of Earth and Ecosystem Sciences: Digital Optical Imaging of Ice Cores for Curation and Scientific Applications	Investigator Web site	http://www.dri.edu/dees-research/1801-digital-optical-imaging-of-ice-cores-for-curation-and-scientific-applications
National Ice Core Laboratory	Related Web site	http://nicl.usgs.gov/
WAIS DIvide Ice Core Web site	Ice core information Web site	http://www.waisdivide.unh.edu/about/site.html

6. Document Information

Acronyms

The following acronyms are used in this document:

Table 4. Acronyms and Abbreviations

Acronym	Description
AIFF	Audio Interchange File Format
FTP	File Transfer Protocol
NICL	National Ice Core Laboratory
NSIDC	National Snow and Ice Data Center
PTS	Pro Tools Sessions
ROI	Report Object Instance
URL	Uniform Resource Locator

Document Creation Date

23 April 2009

Document URL

http://nsidc.org/data/docs/agdc/nsidc0375_mcgwire/index.html