Methane Isotopes in South Pole Firn Air, 2008

Summary

This data set contains depth profiles for delta carbon-13 (δ13C) per mil Pee Dee Belemnite (PDB) and delta deuterium (δD) per mil Standard Mean Ocean Water (SMOW) 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).

Citing These Data

We kindly request that you cite the use of this data set in a publication using the following citation. For more information, see our Use and Copyright Web page.

The following example shows how to cite this data set in a publication. List the principal investigators, year the data set was released, data set title, publisher: NSIDC, and "Digital media":

Sowers, T. 2011. Methane Isotopes from South Pole Firn Air. Boulder, CO, USA: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N55T3HFP.

Overview Table

Category Description
Data format ACSII text file (.txt), Microsoft Excel file (.xlsx)
Spatial coverage and resolution Southernmost Latitude: 90° S
Northernmost Latitude: 90° S
Westernmost Longitude: 180° W
Easternmost Longitude: 180° E
Temporal coverage and resolution Samples were obtained during the 2008/2009 field season and represent the period from approximately 1900 to 2009.
File naming convention 2008_S_Pole_Firn_CH4_isotopes.txt; 2008_S_Pole_Firn_CH4_isotopes.xlsx
File size Files for this data set are less than 51 KB
Parameter(s) Depth (meters)
Delta carbon-13 (‰, PDB) of CH4
Delta deuterium (‰, SMOW) of CH4
Procedures for obtaining data 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. Todd Sowers
Earth and Environmental Systems Institute
The Pennsylvania State University
2217 EES Building
University Park, PA 16802

Technical Contact

NSIDC User Services
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
Boulder, CO 80309-0449  USA
phone: +1 303.492.6199
fax: +1 303.492.2468
form: Contact NSIDC User Services
e-mail: nsidc@nsidc.org

Acknowledgements

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

2. Detailed Data Description

Format

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

File and Directory Structure

Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/AGDC/nsidc0502_sowers_v01/ directory.

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

File Size

Files for this data set are less than 51 KB.

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

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.

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

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.

3. Data Access and Tools

Data Access

Data are available via FTP

Volume

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

Software and Tools

The data can be accessed using standard spreadsheet software.

Related Data Collections

4. 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.

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.

Data Acquisition Methods

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

5. References and Related Publications

Battle, M. et al. 1996. Atmospheric Gas Concentrations over the Past Century Measured in Air from Firn at the South Pole. Nature 383, 231-235.

Sowers, T., S. Bernard, O. Aballain, J. Chappellaz, J.M. Barnola, and T. Marik. 2005. Records of the δ13C of Atmospheric CH4 over the Last 2 Centuries as Recorded in Antarctic Snow and Ice. Global Biogeochemical Cycles 19, doi:10.1029/2004GB002408.

6. Document Information

The following acronyms are used in this document:

Acronym Description
δ13C Delta carbon-13
δD Delta deuterium
PDB Pee Dee Belemnite
SMOW Standard Mean Ocean Water

Document Creation Date

October 2011

Document URL

http://nsidc.org/data/docs/agdc/nsidc0502_sowers/index.html