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US International Trans Antarctic Scientific Expedition (US ITASE) Glaciochemical Data, Version 1

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Summary

Sub-annually resolved ice core chemistry data from various sites on the Antarctic Ice Sheet were obtained from 1999 to 2008 during the US International Trans-Antarctic Scientific Expedition (US ITASE) deployments. Researchers conducted experiments approximately every 100-300 km looking for clues representing climatic conditions over the past 200-1000+ years. Ice cores, obtained for the glaciochemical component of the US ITASE research, were analyzed for soluble major ion content and in some cases trace elements. At each site, a ~3-inch diameter ice core was drilled to depths as great as 120 m. Surface snow samples were collected every ~10-40 km. High-resolution chemical analysis (up to ~75 measurements per meter) was used to define each core-chemistry year based on peaks in Na+, Ca2+, Mg2+, K+, NH4+, Cl-, NO3-, SO42-, CH3SO3- (methylsulfonate), and in some cases trace elements. Extreme events such as volcanic eruptions provide absolute age horizons within each core that are easily identified in chemical profiles. Our chemical analysis is also useful for quantifying anthropogenic impact, biogeochemical cycling, and for reconstructing past atmospheric circulation patterns.

Core-chemistry tab-delimited text files, an accumulation rate Excel file, an Antarctic location map (GIF format), and a table of information for each core (GIF format) are available via FTP.

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.

Citing These Data

Mayewski, P. A. and D. A. Dixon. 2005. US International Trans-Antarctic Scientific Expedition (US ITASE) Glaciochemical Data. Version 1. [indicate subset used]. Boulder, Colorado USA: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N5BR8Q4W.

Overview Table

Category Description
Data format Chemistry data are in tab-delimited text files, and the accumulation data are in an Excel file. An Antarctic location map and a table of information for each core are both in GIF format.
Spatial coverage and resolution Data were collected on the Western Antarctic Ice Sheet (WAIS) within the range of 76.0968° S to 90.0000° S and 0.0000° W to 148.7900° W. Each core was sampled approximately every 2 cm.
Temporal coverage and resolution Data were collected from 1999 to 2008 during the Antarctic summer.
Tools for accessing data The user will need a text editor and spreadsheet software to view the data.
File naming convention File names correspond to the individual core/pit locations where the data were collected. Please visit Images to view a map of the core/pit locations.
File size Files sizes range from 29 KB to 321 KB. The entire data set is approximately 2.3 MB.
Parameter(s) Concentrations of the ions Na+, Cl-, and SO42- (sea salt and non-sea salt) were reported along with the snow water equivalent (SWE). Ca2+, Mg2+, K+, NH4+, NO3-, and CH3SO3- (methylsulfonate)
Version History Version 2 was released July 2013. Please see the Version 2 documentation to obtain the most recent data.
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

Investigators

Paul A Mayewski
Climate Change Institute
Global Science Center, University of Maine
Orono, ME, USA

Daniel A Dixon
Climate Change Institute
Global Science Center, University of Maine
Orono, ME, 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 grant was supported by the National Science Foundation (NSF) Office of Polar Programs (OPP) award OPP-9725057.

2. Detailed Data Description

Format

Chemistry data are in tab-delimited text files, and the accumulation data are in an Excel file. An Antarctic location map and a table of information for each core are in GIF format.

File Naming Convention

File names correspond to the year each core was extracted, along with individual core/pit locations where the data were collected. Data from cores obtained in the Central West Antarctic are preceded with "CWA". Data from cores obtained in the Ross Ice Drainage System obtained in 1995 are preceded with "RIDS". The Up-C core location refers to the Ice Stream C recently named the Kamb Ice Stream. The "SP95_Chem.txt" file contains data from the South Pole core recovered in 1995. The "SDM1994.txt" file contains data from the Siple Dome core recovered in 1994. The data from cores that were extracted prior to the US ITASE deployment in 1999 are included in this data set for comparison purposes. Please visit Images to view a map of the core/pit locations along with a table of information about each core.

File Size

Files sizes range from 29 KB to 321 KB. The entire data set is approximately 2.3 MB.

Spatial Coverage

Southernmost Latitude: 90.0000° S
Northernmost Latitude: 76.0968° S
Westernmost Longitude: 148.7900° W
Easternmost Longitude: 0.0000° W

Spatial Coverage Map

Map: Location of US ITASE traverses

Map: Location of US ITASE traverses

The map above shows the traverse routes of the U.S. portion of the International Trans Antarctic Scientific Expedition (US ITASE).

Temporal Coverage

These US ITASE data were collected during the Antarctic summer from 1999 to 2001. These data were used for reconstruction of sub-annual scale climate variability and changes in the chemistry of the atmosphere over the last 200+ years.

Parameter or Variable

Parameter Description

The researchers analyzed a glaciochemical series of ion concentrations including Na+, Ca2+, Mg2+, K+, NH4+, Cl-, NO3- SO42-, and CH3SO3- (methylsulfonate). They studied annual accumulation rates by using snow water equivalents (SWE). They reported concentrations of the ions Na+, Cl-, and SO42- (sea salt and non-sea salt). Ca2+, Mg2+, K+, NH4+, NO3-, and CH3SO3- (methylsulfonate). The ionic composition of polar ice cores provides a stratigraphic tool for relative dating that can be extremely effective on the Western Antarctic Ice Sheet (WAIS). It also allows researchers to document changes in chemical species source emissions and to characterize the major atmospheric circulation systems affecting WAIS.

Unit of Measurement

Ion concentrations are reported in micrograms per liter (µg/L). SWE is reported in centimeters (cm).

Sample Data Record

The sample data below is from the data file "00-5corepit.txt".

Depth (m) YEAR (AD) Na Cl SO4 nssSO4 ssSO4
0 2001 23.31 48.48 51.63 47.57146 4.058537
0.02 2000.962963 11.13 28.78 24.27 23.22935 1.04065
0.04 2000.925926 1.78 13.93 16.08 16.05919 0.020813
0.06 2000.888889 13.88 26.97 19.55 18.46772 1.082276
0.08 2000.851852 19.01 40.85 19.52 16.77268 2.747317
0.1 2000.814815 20.5 41.37 20.93 17.84968 3.080325
0.12 2000.777778 25.15 40.94 19.18 15.55854 3.621463
0.14 2000.740741 58.98 58.97 25.35 18.68984 6.660163
0.16 2000.703704 199.83 330.43 49.28 27.21746 22.06255
0.18 2000.666667 217.15 379.04 50.2 20.45746 29.74255
0.2 2000.62963 196.14 312.29 41.4 13.752 27.648

3. Data Access and Tools

Data Access

Data are available via FTP.

Volume

The entire data set is approximately 2.3 MB.

Software and Tools

The user will need a text editor and spreadsheet software in order to view the data.

Related Data Collections

4. Data Acquisition and Processing

Sensor or Instrument Description

Data are generated using a new Sneed-Handley continuous melter system and an Ion Chromatograph (IC) instrument. The data consist of dissolved major ion concentrations at sub-annual resolution for the length of each core. The ions Na (sodium), NH4 (ammonium), K (potassium), Mg (magnesium), Ca (calcium), Cl (chloride), NO3 (nitrate), SO4 (sulfate), and MS (methylsulfonate) either individually or in combinations, indicate many different processes occurring in, around, or over Antarctica. By looking at these ion concentrations down ice cores, researchers can obtain accurately dated, sub-annual records of Antarctic meteorological and glaciochemical processes hundreds, or sometimes thousands of years into the past.

The University of Maine's continuous melter (UMCoM) system is housed in a dedicated clean room with HEPA filtered air. Standard clean room procedures are employed during melting. A Wagenbach-style continuous melter system was modified to include a pure Nickel melthead that can be easily dismantled for thorough cleaning. The system allows ice and firn to melt without wicking the meltwater into unmelted core. Unlike ice core melter systems in which the meltwater is directly channeled to online instruments for continuous flow analyses, the UMCoM system collects discrete samples for each chemical analysis under clean conditions.

Data Acquisition Methods

The US ITASE field season involved drilling numerous ice cores and collecting snow pit samples along several traverse segments (see map for core locations). At each core/pit site, a 7.6 cm ice core was drilled to a depth between 50 m and 70 m. Workers wearing non-particulating suits, polyethylene gloves, and particle masks sampled snow pits and processed ice cores. Samples were stored in precleaned polyethylene containers and stored below -15° C until melting immediately prior to chemical analysis. Major ions were analyzed using ion chromatography. High-resolution chemical analysis requiring 30 to 50 measurements per meter was used to define each core-chemistry year based on peaks in Na+, Ca2+, Mg2+, K+, NH4+, Cl-, NO3-, SO42- (sea salt and non-sea salt), and CH3SO3- (methylsulfonate).

5. References and Related Publications

All data users may copy, distribute, display and perform work and make derivative works based on it only if they give the author and data owner credit as outlined below.

Data users must cite the following publications whenever using any part of these data, unless other usage terms have been negotiated and agreed upon with the data set owner

Bertler, N., Mayewski, P.A., Alberto Aristarain, P.Barrett, S.Becagli, Ronaldo Torma Bernardo, Xiao Cunde, M.Curran, Qin Dahe, D.Dixon, Francisco Adolfo Ferron, H. Fischer, Markus Frey, M.Frezzotti, F. Fundel, Christophe Genthon, R.Gragani, G.Hamilton, M.Handley, Sungmin Hong, E.Isaksson, Ren Jiawen, Kokichi Kamiyama, Satoru Kanamori, Eija Karkas, L.Karlˆf, S.Kaspari, K.Kreutz, A.Kurbatov, E.Meyerson, Hideaki Motoyama, R. Mulvaney, Zhang Mingjun, H.Oerter, E.Osterberg, M.Proposito, A.Pyne, U.Ruth, Jefferson Cardia Simoes, B.Smith, S.Sneed, Kimmo Teinila, F. Traufetter, R.Udisti, Aki Virkkula, Okitsugu Watanabe, B.Williamson, E. Wolff, Li Zhongqin, 2006, Snow chemistry across Antarctica, Annals of Glaciology 41, 167-179.


Dixon, D., Mayewski, P.A., Kaspari, S., Sneed, S., and Handley, M., 2004, A 200 year sub annual record of the primary sources of sulfate in West Antarctica, Annals of Glaciology 39, 545-556.

Dixon, D., Mayewski, P.A., Kaspari, S., Sneed, S. and Handley, M., 2005, Connections between West Antarctic ice core sulfate and climate over the last 200+ years, Annals of Glaciology 41, 155-156.

Kaspari, S., Mayewski, P.A., Dixon, D., Spikes, V.B., Sneed, S.B., Handley, M.J., and Hamilton, 2004, Climate variability in West Antarctica derived from annual accumulation rate records from ITASE firn/ice cores, Annals of Glaciology 39, 585-594.


Kaspari, S., Mayewski, P.A., Dixon, D., Sneed, S.B., and Handley, M.J., 2005, Sources and transport pathways for marine aerosol species into West Antarctica, Annals of Glaciology 42, 1-9.

Mayewski, P.A., K. A. Maasch, J.W.C. White, E. Meyerson, I. Goodwin, V.I. Morgan., T. van Ommen, M.A.J. Curran, J. Souney, and K. Kreutz, 2005, A 700 year record of Southern Hemisphere extra-tropical climate variability, Annals of Glaciology 39, 127-132.

Mayewski, P.A., Frezzotti, M., Bertler, N., van Ommen, T., Hamilton, G.H., Jacka, J., Welch, B., Frey, M., Dahe, Q., Ren, J., Simoes, J., Fily, M., Oerter, H., Nishio, F., Iasaksson, E., Mulvaney, R., Holmund, P., Lipenkov, V. and Goodwin, I., 2006, The International Trans-Antarctic Scientific Expedition (ITASE) - An Overview, Annals of Glaciology 41, 180-185.


Mayewski, P.A., Maasch, K., Yan, Y., Kang, S., Meyerson, E., Sneed, S., Kaspari, S., Dixon, D., Morgan, V., van Ommen, T., and Curran, M., 2006, Solar forcing of the polar atmosphere, Annals of Glaciology 41, 147-154.

Mayewski, P.A. and Maasch, K., 2006, Recent warming inconsistent with natural association between temperature and atmospheric circulation over the last 2000 years, Climate of the Past (Discussions), on line: http://www.copernicus.org/EGU/cp/cpd/2/327/cpd-2-327.htm.

Steig, E.J., P.A. Mayewski, D. Dixon, S. Kaspari, M. Frey, D.P. Schneider, S.A. Arcone, G. Hamilton, B. Spikes, M.R. Albert, D.A. Meese, A. Gow, C.A. Shuman, J. White, S. Sneed, J. Flaherty, M. Wumkes and US ITASE Project Members, 2006, High-resolution ice cores from US ITASE (West Antarctica): development and validation of chronologies and determination of precision and accuracy, Annals of Glaciology 41, 77-84.

Yan, Y., Mayewski, P.A., Kang, S., and Meyerson, E., 2005, An ice core proxy for Antarctic circumpolar wind intensity, Annals of Glaciology 41, 121-130.


6. Document Information

List of Acronyms

The following acronyms are used in this document:

CWA: Central West Antarctic
FTP: File Transfer Protocol
ITASE: International Trans Antarctic Scientific Expedition
NSIDC: National Snow and Ice Data Center
RIDS: Ross Ice Drainage System
SWE: Snow water equivalent
WAIS: Western Antarctic Ice Sheet

Document Creation Date

August 2005

Document Revision Date

January 2009

Document Review Date

August 2005

Document URL

http://nsidc.org/data/docs/agdc/nsidc0273_dixon/index.html