Documentation for Ultra-trace gas measurements in the WAIS Divide 06A Ice Core, Version 1

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This data set includes the measurements of trace gases from WAIS Divide 06A ice core analyzed with a gas chromatography mass spectrometry (GC-MS).  The trace gases found in the 207 samples are ethane (C2H6), propane (C3H8), n-butane (n-C4H10), carbonyl sulfide (COS), carbon disulfide (CS2), methyl chloride (CH3Cl), and methyl bromide (CH3Br). 

Detailed Data Description

Two hundred and twelve samples from the WAIS Divide 06A ice core were analyzed for ethane (C2H6), propane (C3H8), n-butane (n-C4H10), carbonyl sulfide (COS), carbon disulfide (CS2), methyl chloride (CH3Cl), and methyl bromide (CH3Br). Five of the samples were lost due to the presence of excessive drill fluid, which causes our pre-concentration system to fail, and mass spectrometer malfunction. All measurements and the associated uncertainties (+/- 1 sigma) are reported as dry-air molar mixing-ratios.
Format

The files are in Microsoft Excel format (.xls).

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File and Directory Structure

Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/AGDC/nsidc0659_aydin directory. Within this directory, there is one file: UCI data submission WAIS06A ice core.xls. There are 16 columns in the file.  See Table 1 for the column information.

Table 1. Column Information
Column Header Description
Depth (m) Depth of the ice core sample 
C2H6 (ppt) Amount of ethane found in sample
err (ppt) Amount of uncertaintity (+/- 1 sigma) for ethane measurement
C3H8 (ppt) Amount of propane found in sample
err (ppt) Amount of uncertaintity (+/- 1 sigma) for propane measurement
C4H10 (ppt) Amount of n-butane found in sample
err (ppt) Amount of uncertaintity (+/- 1 sigma) for n-butane measurement
COS (ppt) Amount of carbonyl sulfide found in sample
err (ppt) Amount of uncertaintity (+/- 1 sigma) for carbonyl sulfide measurement
CS2 (ppt) Amount of carbon disulfide found in sample
err (ppt) Amount of uncertaintity (+/- 1 sigma) for carbon disulfide measurement
CH3Cl (ppt) Amount of methyl chloride found in sample
err (ppt) Amount of uncertaintity (+/- 1 sigma) for methyl chloride measurement
CH3Br (ppt) Amount of methyl bromide found in sample
err (ppt) Amount of uncertaintity (+/- 1 sigma) for methyl bromide measurement
flag 0=no apparent issues; 1=drill fluid detected; 2=potential leak during extraction or analysis

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File Size

The file size is 92 KB.

Spatial Coverage

The WAIS Divide ice core extraction site is at 79.5° S and 112.1° W.

Temporal Coverage

The sample analysis occurred on 28 October 2015.

Parameter or Variable

The data set's parameters are trace gases extracted from the ice core samples.

Parameter Description

The trace gases are ethane (C2H6), propane (C3H8), n-butane (n-C4H10), carbonyl sulfide (COS), carbon disulfide (CS2), methyl chloride (CH3Cl), and methyl bromide (CH3Br).

Sample Data Record

See Figure 1 for a sample of the data.

Sample Data
Figure 1. Sample data 

Software and Tools

Get Data

The data are available via FTP.

Software and Tools

To view the data, use Microsoft Excel.

Data Acquisition and Processing

Data Acquisition Methods

A dry-extraction system was used for extraction of ice core air and the analysis was carried out using a GC-MS system at the University of California, Irvine. See Aydin et al., 2007 for a more detailed discussion on the methodology used for the process.

Error Sources

No correction has been applied for gravitational enrichment in the firn. There was some amount of drill-fluid in 79 of the samples that were analyzed, and are flagged in the data (see Table 1). An additional 5 samples were flagged for potential vacuum leaks that occurred during the extraction or the analysis.

Instrument Description

The instrument used for the analysis was the HP 5890/Micromass Autospec Ultima, which combines gas chromatography with mass spectrometric detection.

Error Sources

The trace gas measurements in the WDC-06A ice core are impacted by in situ production or artifacts associated with the ice core air extraction, with the exception of COS. The paleoatmospheric and biogeochemical implications of the COS measurements are published in two separate articles [Aydin et al., 2014; Aydin et al., in review 2015].

References and Related Publications

REFERENCES

Aydin, M., M. B. Williams, and E. S. Saltzman. 2007. Feasibility of reconstructing paleoatmospheric records of selected alkanes, methyl halides, and sulfur gases from Greenland ice cores. Journal of Geophysical Research - Atmospheres 112(7): D07312. doi: 10.1029/2006JD008027.

Aydin, M., T. J. Fudge, K. R. Verhulst, M. R. Nicewonger, E. D. Waddington,, and E. S. Saltzman. 2014. Carbonyl sulfide hydrolysis in Antarctic ice cores and an atmospheric history for the last 8,000 years. Journal of Geophysical Research - Atmospheres 119(13): 8500-8514. doi: 10.1002/2014JD021618.

Aydin, M., J. E. Campbell, T. J. Fudge, K. M. Cuffey, M. R. Nicewonger, K. R. Verhulst, and E. S. Saltzman. 2015. Changes in atmospheric carbonyl sulfide over the last 54000 years inferred from measurements in Antarctic ice cores. Journal of Geophysical Research - Atmospheres, in review.

Contacts and Acknowledgments

Murat Aydin
University of California, Irvine
Dept. of Earth System Science
Bison Avenue, Croul Hall 1212
Irvine, CA 92697

Eric S. Saltzman
University of California, Irvine
Dept. of Earth System Science
Bison Avenue, Croul Hall 1212
Irvine, CA 92697

Acknowledgments: 

This research was supported by NSF Division of Polar Programs (PLR) Grant Numbers 1043780.

Document Information

DOCUMENT CREATION DATE

11 December 2015

DOCUMENT REVISION DATE