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Data Set ID:
NSIDC-0537

Temperature of the West Antarctic Ice Sheet, Version 1

This data set contains temperature-depth profile measurements taken in 22 boreholes drilled on the West Antarctic Ice Sheet, which exhibit two distinctly different thermal states of basal ice: a warm state and a relatively colder state. The data are available in ASCII Text Format (.txt) and Portable Document Format (PDF) via FTP.

Geographic Coverage

Parameter(s):
  • Glaciers/Ice Sheets > Ice Sheets
Spatial Coverage:
  • N: -81.07364, S: -83.679167, E: -135.825278, W: -148.808333

Spatial Resolution:
  • Varies x Varies
Temporal Coverage:
  • 1 January 1988 to 31 December 2001
Temporal Resolution: Not specified
Data Format(s):
  • PDF
  • ASCII Text
Platform(s) GROUND-BASED OBSERVATIONS
Sensor(s): THERMISTORS
Version: V1
Data Contributor(s): Hermann Engelhardt

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.

Engelhardt, H. 2013. Temperature of the West Antarctic Ice Sheet, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: http://dx.doi.org/10.7265/N5PN93J8. [Date Accessed].

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This data set contains temperature-depth profile measurements taken in 22 boreholes drilled on the West Antarctic Ice Sheet, which exhibit two distinctly different thermal states of basal ice: a warm state and a relatively colder state. The data are available via FTP in ASCII Text Format (.txt) and Portable Document Format (.pdf).

Detailed Data Description

This data set contains temperature-depth profile measurements taken in 22 boreholes drilled on the West Antarctic Ice Sheet, which exhibit two distinctly different thermal states of basal ice: a warm state and a relatively colder state. The warm state shows on Siple Dome and on Whillans Ice Stream. A relatively colder state, found at the Unicorn, the Kamb Ice Stream, and the Bindschadler Ice Stream has basal temperature gradients greater than 50 K km-1. A large block of cold ice stranded and frozen to the bed at the Unicorn, and simultaneously a much warmer ice existing only a few kilometers across the Dragon, and shear margin in fast moving Alley Ice Stream poses a paradox. The relatively cold ice at the Unicorn must have come from a source different from the present Whillans Ice Stream catchment area. It is hypothesized that the Unicorn paradox was created by a super-surge. Also, the stagnant Siple Ice Stream, many relict shear margins, cold patches of ice at the Crary Ice Rise, and ice rafts embedded in the Ross Ice Shelf, all point to a major event triggered either by an internal instability or by a subareal volcanic eruption. Most of these features appeared to have been formed about 500 years ago. Subsequent freeze-on of a 10-20 m thick basal layer of debris-laden ice and water loss had the effect of a slow-down of the ice streams, and in the case of the Kamb Ice Stream an almost complete stoppage.

The following tables give specific information for each borehole file such as location, ice thickness, ice surface velocity, and the date the borehole was drilled.

Note: In the following tables, the year listed in the file name doesn't always match the year listed in the column titled Date Drilled. For example, the T-AIS/WIS-1992-6.txt file name has a date drilled of 17 January, 1993. A field season always runs from November to February; thus, the drilling season for this site started in November 1992, but this specific borehole was actually drilled on 17 January, 1993. Thus, the Date Drilled doesn't always match the date in the file name.

T-AIS/WIS-1988-1.txt
Location
S 83° 29’ 58”, W 138° 25’ 26”
Ice Thickness
1035 m
Ice Surface Velocity
443 m/a
Date Drilled
1 December 1988
T-AIS/WIS-1989-3,4.txt
Location
S 83° 29’ 10”, W 138° 31’ 15”
Ice Thickness
1057 m
Ice Surface Velocity
443 m/a
Date Drilled
18 December 1989
T-AIS/WIS-1991-1.txt
Location
S 83° 29’ 00”, W 138° 25’ 36”
Ice Thickness
1055 m
Ice Surface Velocity
438 m/a
Date Drilled
17 December 1991
T-AIS/WIS-1992-2,6.txt
Location
S 83° 29’ 05”, W 138° 27’ 29”
Ice Thickness
1052 m
Ice Surface Velocity
424 m/a
Date Drilled
12 December 1992
T-AIS/WIS-1992-6.txt
Location
S 83° 32’ 17”, W 138° 27’ 29”
Ice Thickness
1057 m
Ice Surface Velocity
not measured
Date Drilled
17 January 1993
T-AIS/WIS-1995-4,7.txt
Location
S 83° 27’ 43”, W 138° 56’ 47”
Ice Thickness
1026 m
Ice Surface Velocity
not measured
Date Drilled
4 January 1996
T-BIS-1998-4.txt
Location
S 81° 04’ 25”, W 140° 00’ 19”
Ice Thickness
1086 m
Ice Surface Velocity
365 m/a
Date Drilled
23 January 1999
T-ER-1996-12.txt
Location
S 82° 40’ 36”, W 135° 49’ 31”
Ice Thickness
1124 m
Ice Surface Velocity
10.9 m/a
Date Drilled
10 January 1997
T-KIS-1996-2.txt
Location
S 82° 26’ 42”, W 135° 58’ 36°
Ice Thickness
1189 m
Ice Surface Velocity
14 m/a
Date Drilled
26 November 1996
T-KIS-2000-1,2.txt
Location
S 82° 22’ 00”, W 136° 24’ 00”
Ice Thickness
949.4 m
Ice Surface Velocity
3 m/a
Date Drilled
18 December 2000
T-KIS-2000-6.txt
Location
S 82° 25’ 57”, W 136° 24’ 08”
Ice Thickness
1191.8 m
Ice Surface Velocity
12 m/a
Date Drilled
13 January 2001
T-KIS-2000-9.txt
Location
S 82° 23’ 59”, W 136° 24’ 16”
Ice Thickness
1033.5 m
Ice Surface Velocity
6 m/a
Date Drilled
14 January 2001
T-RR-1997-42.txt
Location
S 81° 35’ 47”, W 148° 41’ 38”
Ice Thickness
955 m
Ice Surface Velocity
not measured
Date Drilled
8 January 1998
T-SD-1997-1.txt
Location
S 81° 39’ 30”, W 148° 48’ 30”
Ice Thickness
1004.6 m
Ice Surface Velocity
not measured
Date Drilled
29 November 1997
T-UC-1993-9.txt
Location
S 83° 34’ 24”, W 138° 08’ 58”
Ice Thickness
908.4 m
Ice Surface Velocity
2.8 m/a
Date Drilled
22 December 1993
T-UC-1993-11.txt
Location
S 83° 34’ 56”, W 138° 08’ 45”
Ice Thickness
910.6 m
Ice Surface Velocity
2 m/a
Date Drilled
30 December 1993
T-UC-1993-14.txt
Location
S 83° 40’ 45”, W 138° 22’ 18”
Ice Thickness
1091.6 m
Ice Surface Velocity
1.6 m/a
Date Drilled
9 January 1994
T-UC-1993-16.txt
Location
S 83° 36’ 39”, W 138° 02’ 31”
Ice Thickness
962.3 m
Ice Surface Velocity
0.5 m/a
Date Drilled
19 January 1994
Format

Data are provided in ASCII Text Format (.txt) and Portable Document Format (.pdf).

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File and Directory Structure

Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/AGDC/nsidc0537_engelhardt_V01/ directory. Within this directory, there are 18 text files and 2 PDFs. The text files contain two columns of data. The first column contains temperature data in degree Celsius, and the second column contains height above the bottom of the ice data in meters. Refer to Figure 2. The two PDFs contain temperature plots. Refer to Figures 3 and 4.

T-AIS/WIS-1988-1.txt
T-AIS/WIS-1989-3,4.txt
T-AIS/WIS-1991-1.txt
T-AIS/WIS-1992-2.txt
T-AIS/WIS-1992-6.txt
T-AIS/WIS-1995-4,7.txt
T-BIS-1998-4,5.txt
T-ER-1996-12.txt
T-KIS-1996-2.txt
T-KIS-2000-1,2.txt
T-KIS-2000-6.txt
T-KIS-2000-9.txt
T-RR-1997-42.txt
T-SD-1997-1.txt
T-UC-1993-9.txt
T-UC-1993-11.txt
T-UC-1993-14.txt
T-UC-1993-16.txt
T-cold.pdf
T-warm.pdf

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File Naming Convention

This section explains the file naming convention used for this product with an example.

Example File NameT-AIS/WIS-1991-1.txt

T-LL-YYYY-N.txt

Refer to Table 1 for the valid values for the file name variables listed above.

Where:

Table 1. File Naming Convention
Variable
Description
T
Stands for Temperature
LL
Location of drill site. Refer to Table 2 for a listing of the drill site locations.

Note: The location AIS/WIS refers to one location. AIS is a branch of the Whillans Ice Stream (WIS).
YYYY
Corresponds to the borehole drilling season, not necessarily the exact year it was drilled.
N
The number of the borehole. 

Note: When there are two borehole numbers listed, that means there are two boreholes next to each other at the same drill site, and the data of the two boreholes are merged.
.txt
ASCII Text File
Table 2. Drill Site Locations
Variable
Drill Site Location
AIS
Alley Ice Stream
BIS
Bindschadler Ice Stream
ER
Engelhardt Ridge
KIS
Kamb Ice Stream
RR
Raymond Ridge
SD
Siple Dome
UC
Unicorn1
WIS
Whillans Ice Stream
1The Unicorn is an island with slow moving ice between Alley Ice Stream (AIS) and Van der Veen Ice Stream (VIS), the two branches of Whillan Ice Stream (WIS).
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File Size

Figure 1 lists all the different file sizes.

file size
Figure 1. Files Sizes
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Volume

This data set is 58 KB in size.

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Spatial Coverage

Southernmost Latitude: 83° 40’ 45”
Northernmost Latitude: 81° 04’ 25”
Westernmost Longitude: 148° 48’ 30”
Easternmost Longitude: 135° 49’ 31”

Spatial Resolution

0.05°C

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Temporal Coverage

Data set temporal coverage is from 1988 to 2001.

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Parameter or Variable

Ice Temperature
West Antarctic Ice Sheet

Sample Data Record

The text files for this data set contain two columns of data. The first column contains temperature data in degree Celsius, and the second column contains data about the height above the bottom of the ice in meters. Figure 2 is a sample data record of data file T-AIS/WIS-1992-2.txt.

The PDF files for this data set contain a cold temperature plot and a warm temperature plot courtesy of Engelhardt 2004b. Refer to Figures 3 and 4.

Figure 2. Sample Date Record for file T-AIS/WIS-1992-2.txt
temperature cold plot
Figure 3. Cold Temperature Plot Sample Data Record for File T-cold.pdf
temperature warm plot
Figure 4. Warm Temperature Plot Sample Data Record for File T-warm.pdf

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Software and Tools

Software and Tools

These data files can be viewed with any text editor.

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Data Acquisition and Processing

The temperature measurements were taken in boreholes drilled on the West Antarctic Ice Sheet. Strings of temperature-calibrated thermistors were inserted into the water filled boreholes and left to freeze. The thermistors were encased in pressure tight tubings to prevent them from being altered by the high pressure in the refreezing process. The resistances of the thermistors were re measured over several years as the temperature equilibrated with the surrounding ice. The corresponding temperatures are known to better than 0.05° C.

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References and Related Publications

Contacts and Acknowledgments

Dr. Hermann Engelhardt
University of Maryland
Center of Environmental Sciences
Appalachian Laboratory
301 Braddock Road
Frostburg, MD 21532-2307
E-mail: engel@caltech.edu
Telephone: 301 689 3405

Acknowledgments: 

This research was supported by NSF OPP Grant Numbers 8519083 and 9615420.

Document Information

DOCUMENT CREATION DATE

April 2013

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

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