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Data Set ID:
NSIDC-0502

Methane Isotopes in South Pole Firn Air, 2008, Version 1

This data set contains depth profiles for delta carbon-13 (δ13C) and delta deuterium (δD) of methane (CH4) in South Pole firn air. The investigators obtained air samples from two boreholes during December 2008 and January 2009, and subsequently determined isotope ratios at 18 depths. The profiles represent a roughly 100-year history of the isotopic composition of CH4 at South Pole Station (no depth-age model provided).

Data are available via FTP as an ASCII text file (.txt) and a Microsoft Excel file (.xlsx).

Geographic Coverage

Spatial Coverage:
  • N: 90, S: -90, E: 180, W: -180

Spatial Resolution: Not Specified
Temporal Coverage:
  • 1 December 2008 to 31 January 2009
Temporal Resolution: Not specified
Parameter(s):
  • Ice Core Records > Isotopes > Delta Carbon-13 of Methane
  • Ice Core Records > Isotopes > Delta Deuterium of Methane
  • Snow/Ice > Snow Depth > Meters Below Surface
Platform(s) GROUND-BASED OBSERVATIONS, LABORATORY
Sensor(s): MASS SPECTROMETERS
Data Format(s):
  • Microsoft Excel
  • ASCII Text
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. 2011. Methane Isotopes in South Pole Firn Air, 2008, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: http://dx.doi.org/10.7265/N55T3HFP. [Date Accessed].

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Detailed Data Description

Format

Data are available as an ASCII text file (.txt) and a Microsoft Excel file (.xlsx).

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File and Directory Structure

Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/AGDC/nsidc0502_sowers_V01/ directory.

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File Naming Convention

Files are named according to the following convention:

2008_S_Pole_Firn_CH4_isotopes.txt; 2008_S_Pole_Firn_CH4_isotopes.xlsx

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File Size

Files for this data set are less than 51 KB.

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Volume

The total volume of the data set is less than 51 KB

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Spatial Coverage

Data were recovered from two boreholes approximately 20 meters apart at South Pole Station.

Southernmost Latitude: 90° S
Northernmost Latitude: 90° S
Westernmost Longitude: 180° W
Easternmost Longitude: 180° E

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Temporal Coverage

The samples, obtained during December 2008 and January 2009, represent 18 measurements of δ13C (‰,  PDB) and δD (‰,  SMOW) of methane corresponding to the period from approximately 1900 to 2009.

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Parameter or Variable

Parameters are depth (meters below surface) and measurements of δ13C (‰,  PDB) and δD (‰,  SMOW) of methane.

Sample Data Record

The following example shows sample data from nsidc0502_sowers_v01.txt:

DEPTH
d13C
d13C STD
dD
dD STD
0.00
-47.09
0.04
-79.6
4.50
19.73
-47.31
0.05
-84.1
3.25
30.04
-47.52
0.11
-81.0
5.61
39.94
-47.59
0.05
-87.5
4.10
60.14
-47.80
0.08
-85.9
2.06
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Software and Tools

The data can be accessed using standard spreadsheet software.

Quality Assessment

The investigator analyzed 156 firn air samples from the 2008-2009 field season and 44 standards for δ13C and δD of CH4. The average standard deviation of replicate samples at each of the 18 depths was ±0.13‰ and ±4.2‰ for δ13C and δD, respectively.

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Data Acquisition and Processing

Theory of Measurements

Changes in δ13C and δD of atmospheric CH4 reflect changes in systems that contribute to the isotopic composition of the gas, such as biomass burning, industrial and agricultural productivity, and biogenic activity in terrestrial, oceanic, and wetland ecosystems.

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Data Acquisition Methods

Firn air samples were recovered from two boreholes approximately 20 meters apart at South Pole Station.

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Sensor or Instrument Description

Isotopic ratios were analyzed with a Finnigan MAT 252 mass spectrometer. Refer to Sowers et al. (2005) for detailed instrument descriptions and processing steps.

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References and Related Publications

Contacts and Acknowledgments

Dr. Todd Sowers
Earth and Environmental Systems Institute
The Pennsylvania State University
2217 EES Building
University Park, PA 16802

Acknowledgements: 

This research was supported by the National Science Foundation (NSF) Office of Polar Programs (OPP) grant ANT 0739491.

Document Information

Document Creation Date

October 2011

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