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Data Set ID:

Methane Isotopes from the WAIS Divide Ice Core, Version 1

This data set includes methane (CH4) isotope data from the West Antarctic Ice Sheet (WAIS) Divide ice core, WDC05A, in Antarctica. The data include depth, gas age, and the isotopic composition of methane (∂13C and ∂D of CH4). The ice core was collected during the 2005-2006 Antarctic field season. The CH4 isotope data was generated in 2008 using wet extraction methodology. Samples span the last 1,000 years, at a resolution of about 15 years. Data for samples above 69 meters were from firn air, and data below 69 meters from ice. The dating of the ice was based on continuous chemical analyses above 69 meters and Electrical Conductivity/Dielectric Property (ECM/DEP) measurements from ice. Dating uncertainty is estimated to be better than five years.

Data are available via FTP in Microsoft Excel (.xls) tab delimited format

Geographic Coverage

Spatial Coverage:
  • N: -79.47, S: -79.47, E: 112.09, W: 112.09

Spatial Resolution: Not Specified
Temporal Coverage:
  • 1 January 2008 to 30 December 2008
Temporal Resolution: 60 month
  • Glaciers/Ice Sheets > Ice Sheets
  • Ice Core Records > Isotopes
  • Ice Core Records > Methane
  • Snow/Ice > Snow/Ice Chemistry
Data Format(s):
  • Microsoft Excel
Version: V1
Data Contributor(s): Todd Sowers

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.

Sowers, T. A. 2009. Methane Isotopes from the WAIS Divide Ice Core, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: [Date Accessed].

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Detailed Data Description


Data are in Microsoft Excel (.xls) format.

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File and Directory Structure

Data are available on the FTP site in the directory. Within this directory, there is one data file, titled WAIS_d13C_dD _CH4.xls, and a readme file in plain text (.txt) format.

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File Naming Convention

This data set consists of one file, WAIS_d13C_dD _CH4.xls, which contains isotope measurements from CH4 samples in the WAIS Divide ice core.

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File Size

The data file is 32 KB.

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Spatial Coverage

Data are from the WAIS Divide ice core WDC05A in Antarctica.

Southernmost Latitude: 79.47° S
Northernmost Latitude: 79.47° S
Westernmost Longitude: 112.09° E
Easternmost Longitude: 112.09° E

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Temporal Coverage

Ice age data ranges from 1,000 years before present to present.

Temporal Resolution

Ice age data have an average resolution of 15 years.

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Parameter or Variable

This data set contains depth, age, and concentration measurements for two CH4 isotopes, δ13C and δD. Data for samples above 69 meters is firn air (chemical data), and data below 69 meters is ice, measured in ECM/DEP.

Parameter Description

Table 1. Parameter Description
Parameter Description
Depth Sample depth, in meters below surface (mbs)
Gas age Gas age, in date AD.
δ13C (CH4) Concentration of δ13C in CH4, in parts per million Pee Dee Belemnite (PDB)
δD (CH4) Concentration of δD in CH4, in parts per million Standard Mean Ocean Water (SMOW)

Sample Data Record

Depth (mbs) Gas Age (AD) δD(CH4) 
(permil SMOW)
Depth (mbs) Gas Age (AD) δ13CH4
(permil PDB)
0 2006 -80.0 0 2006 -47.0
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Software and Tools

Data are accessible using spreadsheet software.

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Data Acquisition and Processing

Theory of Measurements

Wet gas extraction, sample dating, and isotope concentration measurement methodologies are detailed in Sowers et. al., 2005Sowers, 2006, and Sowers, 2009. For samples above 69 meters, measurements were performed on firn air samples and dated using continuous chemical analyses. For samples deeper than 69 meters, analyses were performed on occluded gas bubbles with dating obtained from ECM/DEP counts.

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Quality Assessment

Data precision is 0.1 meters for depth, 5 years for gas age, 4 parts per million for δD, and 0.3 parts per million for δ13C.

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References and Related Publications

Contacts and Acknowledgments

Dr. Todd A. Sowers
Penn State University 
Earth and Environment Science Institute
Penn State University 
University Park, PA 16802


This research was supported by NSF Office of Polar Programs grant 0440759.

Document Information

Document Creation Date

20 November 2009

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