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US ITASE Stable Isotope Data, Antarctica

Summary

This data set includes stable isotope measurements from snow pits, firn, and ice cores collected by the the US component of the International Trans-Antarctic Scientific Expedition ( ITASE). The ITASE program aims to collect and interpret a continental-wide array of environmental parameters assembled through the coordinated efforts of scientists from several nations.

These data were collected between 1999 and 2007. The data have been compiled into single files for each sampling site, though in some cases a file contains data from more than one ice core or snow pit. Each file in the data set includes deuterium/hydrogen (δD) and/or 18-oxygen/16-oxygen (δ18O) ratios, depths, and in some cases ice age or other information. Further details regarding the data are provided in each data file. Data are available via FTP in ASCII text format (.txt). Data were collected during five Antarctic field seasons from 1999 to 2007. Data from 1999 to 2002 are currently available. Data from 2003 to 2007 will be added in the future.

Citing These Data

We kindly request that you cite the use of this data set in a publication using the following citation example. 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. Users must also cite the appropriate published references, listed in the header information for each file.

Steig, E. J. 2009. US ITASE Stable Isotope Data, Antarctica. Boulder, Colorado, USA: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N5NZ85MD.

Overview Table

Category Description
Data format ASCII text (.txt)
Spatial coverage and resolution Southernmost Latitude: 90°S
Northernmost Latitude: 65°S
Westernmost Longitude: 130°W
Easternmost Longitude: 85°W
Temporal coverage and resolution Data were collected between 1999 and 2007.
File naming convention ITASE_1999_1.txt
ITASE_2000_1.txt
File size File sizes range from 26 KB to 170 KB.
Parameter(s) Oxygen Isotope (δ18O)
Deuterium Isotopes (δD)
Deuterium Excess (dxs)
Ice Core Depth (meters)
Ice Age
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)

Dr. Eric J. Steig
University of Washington
Department of Earth and Space Sciences
70 Johnson Hall City: Seattle Province or State: WA Postal Code:
Seattle, Washington 98195
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

Acknowledgements

This research was supported by NSF OPP grants 0440414 and 0196105.

2. Detailed Data Description

Format

Data are ASCII text format (.txt)

File and Directory Structure

Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/AGDC/steig_nsidc_0425/ directory. Within this directory, there are currently 15 ASCII text files containing data collected in 1999 to 2002. Additional data files for 2003 to 2007 will be added in the future.

File Naming Convention

Files are named according to the following convention and as described in Table 1. Additional information on the ice cores and snow pits is provided in the heading of each data file.

ITASE_YYYY_N.EXT

Where:

Table 1. File Naming Convention
Variable Description
ITASE Project name
YYYY 4-digit year of data collection
N Site number
EXT File extension

Example: ITASE_1999_1.txt: Contains data from the ITASE expedition collected in 1999.

File Size

File size ranges between 26 KB and 170 KB.

Spatial Coverage

Southernmost Latitude: 90°S
Northernmost Latitude: 65°S
Westernmost Longitude: 130°W
Easternmost Longitude: 85°W

Location Map

itase core and route map
Figure 1. Map of ITASE Traverse Routes and Ice Core Locations
Image courtesy US ITASE Program

Temporal Coverage

Data were collected during five Antarctic field seasons from 1999 to 2007. Data from 1999 to 2002 are currently available. Data from 2003 to 2007 will be added in the future.

Temporal Resolution

Weekly to annual

Parameter or Variable

Parameters include oxygen and deuterium isotope ratios, and in some case ice age. Each data file contains additional details on the specific measurements and parameters in the file.

Parameter Description

Table 2. Parameter Description
Parameter Description
Depth Top and bottom sample depth, in meters
Age Sample age at top and bottom of sample, in calendar year
d180 Stable oxygen ratio (18-oxygen/16-oxygen), in parts per million
delD Deuterium ratio, in parts per million
dxs Deuterium excess, in parts per million
Sample number Sample identification number

Sample Data Record

Example: ITASE_2000_1.txt

Depth Top (m) Depth Bottom (m) Age Top (calendar year) Age Bottom d18O (per mil) delD (per mil) dxs (per mil) Sample Number
0 0.02 2001 2000.97 -29.83 -239.02 -0.36 ITASE2000C1_p442

Quality Assessment

Percent Isotope ratios are normalized on the V-SWOW / SLAP scale; precision is better than 0.1 per mill for d18O and better than 1 per mill for and delD.

3. Data Access and Tools

Data Access

Data are available via FTP.

Volume

The total volume of the data set will be approximately 4 MB, when all data files are available.

Software and Tools

Data are accessible using spreadsheet software.

Related Data Collections

4. Data Acquisition and Processing

Stable isotope concentrations (δ18O and δD) were analyzed by mass spectrometry, using CO2 equilibration and Cr reduction, in a laboratory at the University of Washington. For more information, see Steig, et al. 2005, and Schneider, et al., 2005, and the additional references cited below.

5. References and Related Publications

Steig E. J., P. A. Mayewski, D. A. Dixon, M. M. Frey, S. D. Kaspari, D. P. Schneider, S. A. Arcone, G. S. Hamilton, V. B. Spikes, M. Albert, D. Meese, A. J. Gow, C. A. Shuman, J. W. C. White, S. Sneed, J. Flaherty, and M. Wumkes.  2005. High-resolution ice cores from US ITASE (West Antarctica); development and validation of chronologies and estimate of precision and accuracy. Annals of Glaciology 41: 63-70.

Schneider D. P., E. J. Steig, and T. van Ommen. 2005. Interpretation of high resolution ice core stable isotope records from Antarctica: towards interannual climate reconstruction. Annals of Glaciology 541: 77-84.

Schneider D. P., and E. J. Steig.  2008. Ice cores record significant 1940s Antarctic warmth related to tropical climate variability. Proceedings of the National Academy of Sciences, 105(34): 12154-12158

Schneider D. P., E. J. Steig, T. J. van Omment, D. A. Dixon, P. A. Mayewski, J. M. Jones, and C. M. Bitz. 2006. Antarctic temperatures of the past two centuries from ice cores.  Geophysical Research Letters 33, L16707, doi:10.1029/2006GL027057.

Jacobel R., B. Welch, E. J. Steig, and D. P. Schneider. 2005. Hercules Dome, Antarctica – an optimal site for deep ice core drilling. Journal of Geophysical Research – Earth Surface 110: F01015, doi:10.1029/2004JF000188.

Schneider D. P., and D. C. Noone. 2008. Spatial covariance of water isotopes in ice cores during 20th Century climate change. Journal of Geophysical Research, 112: D18105, doi:10.1029/2007JD008652.

Gregory, S., and D. Noone. 2008. Variability in the teleconnection between the El Nino-Southern Oscillation and West Antarctic climate. Journal of Geophysical Research, 113, D17110, doi:10.1029/2007JD009107.

Table 3 lists related Web pages:

Table 3. Related Documents
Document Description URL
Antarctic Glaciological Data Center (AGDC) AGDC Web site http://nsidc.org/agdc/
United States International Trans Antarctic Scientific Expedition (US ITASE) NSIDC US ITASE data Web site http://nsidc.org/agdc/itase.html
Ice Reader Ice Reader Web site http://icereader.org
US International Trans- Antarctic Scientific Expedition ITASE Project Web site http://www2.umaine.edu/itase
University of Washington ITASE Web page UW ITASE Web site http://depts.washington.edu/itase

6. Document Information

Acronyms

The acronyms used in this document are listed in Table 4.

Table 4. Acronyms and Abbreviations
Acronym Description
δD Deuterium ratio
δ18O Ratio of 18-Oxygen/16-Oxygen
FTP File Transfer Protocol
ITASE International Trans- Antarctic Scientific Expedition
NSIDC National Snow and Ice Data Center
TXT ASCII text file extension
URL Uniform Resource Locator

Document Creation Date

18 September 2009

Document URL

http://nsidc.org/data/docs/agdc/nsidc0425_steig/index.html