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.
The following example shows how to cite the use of this data set in a publication. For more information, see our Use and Copyright Web page.
The following example shows how to cite the use of this data set in a publication. List the principal investigators, year of data set release, publisher: NSIDC, and digital media.
Sowers, T. 2009. Methane isotopes from the WAIS divide ice core. Boulder, Colorado, USA: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N5J67DW0.
| Category | Description |
|---|---|
| Data format | Microsoft Excel (.xls) tab delimited |
| Spatial coverage and resolution |
Southernmost Latitude: 79.47°S Northernmost Latitude: 79.47°S Westernmost Longitude: 112.09°E Easternmost Longitude: 112.09°E |
| Temporal coverage and resolution | The WAIS Divide ice core WDC05A was drilled in 2005. Data were collected in 2008. Ice age dates start at 1,000 years before present. |
| File naming convention | WAIS_d13C_dD _CH4.xls |
| File size | 32 KB |
| Parameter(s) | Depth Gas age Concentration of δ13C and δD in CH4, in parts per million |
| Procedures for obtaining data | Data are available via FTP. |
Dr. Todd A. Sowers
Penn State University
Earth and Environment Science Institute
Penn State University
University Park, PA 16802
USA
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
This research was supported by NSF Office of Polar Programs grant 0440759.
Data are in Microsoft Excel (.xls) tab delimited format.
Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/AGDC/sowers_nsidc_0435/ directory. Within this directory, there is one data file, titled WAIS_d13C_dD _CH4.xls, and a readme file in plain text (.txt) format.
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.
The data file is 32 KB.
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
Ice age data ranges from 1,000 years before present to present.
Ice age data have an average resolution of 15 years.
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 |
|---|---|
| Depth | Sample depth, in meters below surface (mbs) |
| Gas age | Gas age, in date AD. |
| d13C (CH4) | Concentration of δ13C in CH4, in parts per million Pee Dee Belemnite (PDB) |
| dD (CH4) | Concentration of δD in CH4, in parts per million Standard Mean Ocean Water (SMOW) |
| Depth (mbs) | Gas Age (AD) | dD(CH4) (permil SMOW) |
Depth (mbs) | Gas Age (AD) | d13CH4 (permil PDB) |
| 0 | 2006 | -80.0 | 0 | 2006 | -47.0 |
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.
Data are available via FTP.
The data set is 32 KB.
Data are accessible using spreadsheet software.
Wet gas extraction, sample dating, and isotope concentration measurement methodologies are detailed in Sowers et. al., 2005, Sowers, 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.
Mischler, J. A., T. A. Sowers, R. B. Alley, M. Battle, J. R. McConnell, L. Mitchell, T. Popp, E. Sofen, and M. K. Spencer. 2009. Carbon and hydrogen isotopic composition of methane over the last 1000 years. Global Biogeochemical Cycles, 23, GB4024, doi:10.1029/2009GB003460.
Sowers, T. 2006. Late Quaternary atmospheric CH4 isotope record suggests marine clathrates are stable. Science 311: 838-841,doi:10.1126/science.1121235.
Sowers, T., S. Bernard, O. Aballain, J. Chappellaz, J.-M. Barnola and T. Marik. 2005. Records of the d13C of atmospheric CH4 over the last two centuries as recorded in Antarctic snow and ice. Global Biogeochemical Cycles. doi:10.1029/2004GB002408.
Sowers, T. A. 2009. Atmospheric methane isotope records covering the Holocene period. Quaternary Science Reviews. doi:10.1016/j.quascirev.2009.05.023.
The following related documents are available
| Document | Description | URL |
|---|---|---|
| Antarctic Glaciological Data Center (AGDC) | Data Center Web site | http://nsidc.org/agdc/ |
| Earth and Environmental Systems: Todd Sowers | Investigator Web site | http://www.eesi.psu.edu/people/Sowers.shtml |
| West Antarctic Ice Sheet Divide Ice Core | Project Web site | http://www.waisdivide.unh.edu/ |
The following acronyms are used in this document.
| Acronym | Description |
|---|---|
| CH4 | Methane |
| ECM/DEP | Electrical Conductivity and Dielectric Property |
| FTP | File Transfer Protocol |
| MBS | Meters Below Surface |
| NSIDC | National Snow and Ice Data Center |
| PDB | Pee Dee Belemnite |
| SMOW | Snow Mean Ocean Water |
| URL | Uniform Resource Locator |
| YBP | Years Before Present |
20 November 2009
http://nsidc.org/data/docs/agdc/nsidc0435_sowers/index.html
