On Wednesday, April 25 from 9:00 a.m. to 12:00 p.m. (USA Mountain Time), the following data collections will not be available due to planned system maintenance: AMSR-E, Aquarius, High Mountain Asia, IceBridge, ICESat/GLAS, MEaSUREs, MODIS, NISE, SMAP, and VIIRS. 

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Data Set ID:
NSIDC-0654

WAIS Divide Ice Core Vertical Thin Section Low-resolution Digital Imagery, Version 1

This data set consists of a comprehensive, frame-stitched low‐resolution set of digital images of vertical thin sections of the main core (WDC 06A) from WAIS Divide.

Geographic Coverage

Parameter(s):
  • Ice Core Records > Grain Size
Spatial Coverage:
  • N: -79.467, S: -79.467, E: -112.085, W: -112.085

Spatial Resolution:
  • 20 m
Temporal Coverage:
  • 1 January 2008 to 30 August 2013
Temporal Resolution: Not specified
Data Format(s):
  • JPEG
  • Microsoft Excel
Platform(s) Laboratory
Sensor(s): DSLR
Version: V1
Data Contributor(s): Joan Fitzpatrick, Eric Cravens
Please contact the data provider for the correct Data Citation for this data set.

Literature Citation

As a condition of using these data, we request that you acknowledge the author(s) of this data set by referencing the following peer-reviewed publication.

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This data set consists of a comprehensive, frame-stitched low‐resolution set of digital images of vertical thin sections of the main core (WDC 06A) from WAIS Divide.

Detailed Data Description

Format

Images are in JPEG (.jpg) format.  Metadata for the images are available in Microsoft Excel format (.xlsx).

File and Directory Structure

Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/AGDC/nsidc0654_jfitzpatrick directory. Within this directory, there is one folder, 1 AGDC jpgs/, and one file, Thin-Section-Images-METADATA.xlsx. The folder contains 170 images of the vertical thin sections from the WDC 06A ice core, and the file consists of five columns of metadata relevant to each image. Refer to Table 1 for a description of the the content within each column.

Table 1. Column Descriptions
Column Header Descriptions
Sample Identifier Lists each of the sample images. 
True Top Depth (m) True top depth in meters as determined by the field core processing line (cpl) over the depth interval 120 - 580 m, and the National Ice Core Laboratory (NICL) cpls below this depth
Dimensions (px) Height and width of the image in pixels
File Size (MB) Size of the file in MB
Mean Equiv. Diamter (mm) Mean grain size as equivalent circular diamter (mm) derived from the image
Analyzed Grain Count (n) Number of grains measured

File Naming Convention

Each image file name includes the ice core name, the depth at which the sample was taken, and the notation that the sample was a vertical thin section (VTS) (see to Table 2). When multiple images were taken at the same depth, the file name includes either the number 1 or 2 and a letter to indicate separate images.

Example: WDC 06A 1005 VTS.jpg
WDC 06A 2968 VTS 1a.jpg
WDC 06A xxxx VTS xx.jpg

Table 2. File Naming Convention
Variable Description
WDC WAIS Divide Ice Core
06A Ice core number
xxxx Sample depth
VTS Vertical thin section
xx Indicates a separate image when multiple images were taken at the same depth

File Size

The image files range in size from 0.41 MB to 3.6 MB.  The Excel file is 57.7 KB.

Volume

The volume for all files in the data set is ~260 MB.

Spatial Coverage

The ice core was drilled at the WAIS Divide, at latitude 79°28 S and longitude 112°05 W.

Spatial Resolution

Spatial resolution is every 20 m.

Temporal Coverage

Temporal coverage for the data is 1 January 2008 to 30 August 2013.

Temporal Resolution

Temporal resolution varies.

Parameter or Variable

The parameter for the data is grain size.

Sample Data Record

Refer to Figure 1 for a sample of the data in the Thin-Section-Images-METADATA.xlsx file (this image is only a partial representation of the rows in the file). Figure 2 is a sample of the .jpg image files.

Metadata File Sample
Figure 1. Sample of Thin-Section-Images-METADATA.xlsx
Sample of an Image File
Figure 2. WDC 06A 1005 VTS.jpg

Software and Tools

Get Data

Data are available via FTP.

Software and Tools

The data is accessible with any image viewer for the image files (.jpg) and Microsoft Excel for the metadata file.

Data Acquisition and Processing

Data Acquisition Methods

All images were acquired in cross-polarized light at a sample thickness of approximately 350 microns. Refer to Fitzpatrick, J.J., 2013 for the detailed methodology.

Derivation Techniques

Processing Steps

Personnel took images with a Nikon D90 DSLR camera. Images for a given thin section were assembled using Photoshop™. A Grain Mesh was extracted utilizing functions of  Photoshop™ and reviewed.  The finalized version of the grain mesh was analyzed using the Fovea Pro™ plug-in for Photoshop™.  Resulting data are summarized in Excel files.

References and Related Publications

Contacts and Acknowledgments

Dr. Joan J. Fitzpatrick
U. S. Geological Survey
Geosciences and Environmental Change Science Center
P.O. Box 25046, DFC, MS 980
Lakewood, CO 80225 U. S. A.

Eric D. Cravens
U. S. Geological Survey
Geosciences and Environmental Change Science Center
P.O. Box 25046, DFC, MS 980
Lakewood, CO 80225 U. S. A.

Acknowledgments: 

This research was supported by NSF Division of Polar Programs (PLR) Grant Number 0539578 and the U. S. Geological Survey Climate and Land Use Change Program.

Document Information

DOCUMENT CREATION DATE

1 March 2016

DOCUMENT REVISION DATE

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

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