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Atmospheric CO2 Trapped in the Ice Core from Siple Dome, Antarctica

Summary

These data are CO2 concentration of the air contained in Siple Dome ice core, Antarctica. The study was conducted between January 2001 and March 2003 on a deep ice core from Siple Dome Core A, located at 81.66 S, 148.82 W. The data covers up to the Termination II (around 140,000 years ago). The parameters are depth in meters and carbon dioxide (CO2) concentration in part per million (ppm). The deepest depth (>995 m) show CO2 values of more than 390 ppm, suggesting reaction and mixing near the bottom with a till ice layer (>1001.8 m), and the intrusions of different ice flows that were laterally located near bed rock. Although deep CO2 values cannot be dated in any way, two of the deepest CO2 results (~ 200 ppm) indicate ages of early Termination II or the penultimate glacial period.

For each data point, four to six samples from the same depth interval were dry-extracted mechanically. Each sample has a volume of 4~6 cm3. CO2 concentration was measured with IR tunable diode laser spectroscopy, scanning a single vibrational-rotational absorption line.

Citing These Data

Ahn, J., M. Wahlen, and B. Deck. 2003. Atmospheric CO2 Trapped in the Ice Core from Siple Dome, Antarctica. Boulder, CO: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N5N877Q9.

Overview Table

Category Description
Data format ASCII text file
Spatial coverage and resolution 81.66°S, 148.82°W
Temporal coverage January 2001 to March 2003
File size 30 KB
Parameter(s) Carbon dioxide (Co2)
Procedures for obtaining data Data are 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) Name and Title

Jinho Ahn
Martin Wahlen
Bruce Deck
Principal Investigator

Scripps Institution of Oceanography
University of California San Diego
La Jolla, California, USA

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

2. Detailed Data Description

Format

Data are provided as an ASCII text file.

File Size

The data file is 30 KB.

Spatial Coverage

Ice core A was taken at 81.66°S, 148.82°W.

Temporal Coverage

The study was performed between January 2001 and March 2003.

Parameter or Variable

Parameter Description

The measured parameter is CO2 at various depths in the ice core.

Unit of Measurement

Unit of measurement is parts per million (ppm).

Parameter Source

The study was conducted on a deep ice core (Core A) taken from the West Antarctic Ice Sheet. For more information please see the WAISCORES data site.

Sample Data Record

The sample below shows the data in terms of the ice core depth (in meters), the age of the CO2 found (in thousands of years before present (BP)), the CO2 (in ppm), and the change in CO2 (in ppm).

Depth m Gas age
kyrBP
CO2 ppm +/- ppm
90.510 0.368 281.19 3.93
104.375 0.496 278.17 2.45
119.854 0.649 288.84 2.99
134.830 0.798 283.11 1.69
149.870 0.981 286.41 0.76

3. Data Access and Tools

Data Access

Data are available via FTP.

4. Data Acquisition and Processing

Sensor or Instrument Description

CO2 concentration was measured with an infrared (IR) tunable diode laser spectroscopy, scanning a single vibrational-rotational absorption line.

Data Acquisition Methods

For each data point, four to six samples from the same depth were dry extracted mechanically. Each sample has a volume of 4~6 cm3. The air was condensed into small cold traps cooled by a cryogenic cooler to about 32 K. Standardization was achieved by admitting standard air samples over the crushed ice mimicking the conditions of the crushing (in high pressure tanks with CO2 concentrations of 330, 240, and 163 ppm). After all traps were full they were warmed up to about -70 degree C and dispensed into an IR cell at constant pressure and temperature with a bellows assembly for scanning. The absorption was measured with an InSb detector. The IR cell, the detector, and a grating spectrometer (for single mode emission selection) were enclosed in a plexiglass housing flushed with nitrogen to expel the air.

5. References and Related Publications

Wahlen, M., D. Allen, B. Deck, and A. Herchenroder. 1991. Initial measurement of CO2 concentrations (1530 to 1940 AD) in air occluded in the GISP2 ice core from central Greenland, Geophysical Research Letters 18: 1457-1460.

Smith, H.J., M. Wahlen, D. Mastroianni, and K. Taylor. 1997. The CO2 concentration of air trapped in GISP2 ice from the Last Glacial Maximum-Holocene transition. Geophysical Research Letters 24, 1-4.

Smith, H.J., M. Wahlen, D. Mastroianni, K. Taylor, and P. Mayewski. 1997. The CO2 concentration of air trapped in Greenland Ice Sheet Project 2 ice formed during periods of rapid climate change. Journal of Geophysical Research 102: 26577-26582.

Taylor, K.C., J.W.C. White, J.P. Severinghaus, E.J. Brook, P.A. Mayewski, R.B. Alley, E.J. Steig, M.K. Spencer, E. Meyerson, D.A. Meese, G.W. Lamorey, A. Grachev, A.J. Gow, and B.A. Barnett. 2004. Abrupt late glacial climate change in the Pacific sector of Antarctica. Quaternary Science Review 23: 7-15.

Taylor, K.C., R.B. Alley, D.A. Meese, M. Spencer, E. Brook, N. Dunbar, B. Finkle, T.J. Gow, A. Kurbatov, P.A. Mayewski, E. Meyerson, K. Nishiizumi, and G.A. Zielinski. 2003. Dating the Siple Dome, Antarctic ice core by manual and computer interpretation of annual layering. Journal of Geophysical Research. In preparation.

Gas age scale for the 97.6 to 40kyr from Ed Brook and Michael Bender (personal communication).

For the last 40 kyr CO2 data:

Ahn, J., M. Wahlen, B.L. Deck, E.J. Brook, P.A. Mayewski, K.C. Taylor, J.W.C. White. 2004. A record of atmospheric CO2 during the last 40,000 years from the Siple Dome, Antarctica ice core. Journal of Geophysical Research - Atmospheres (The data older than 40 kyrBP can only be used with permission by the authors.)

6. Document Information

Document Creation Date

December 2003

Document URL

http://nsidc.org/data/docs/agdc/nsidc0202_wahlen/