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Ross Ice Drainage System (RIDS) Ice Core Glaciochemical Analysis

Summary

The Ross Ice Drainage System (RIDS) project provides a high-resolution record of atmospheric chemical deposition taken from several ice cores and snow pits located at sites within or immediately adjacent to the Ross Ice Drainage System. Three sites were visited during a 1995 traverse in inland West Antarctica. The traverse was 158 km, trending 26° from Byrd Surface Camp. The core from site A (78°44'S, 116°20'W) is 148 m deep, the core from site B (79°27.66'S, 118°02.68'W) is 60 m deep, and the core from site C (80°00.85'S, 119°33.73'W) is 60 m deep. Glaciochemical analysis focuses on the major ions deposited from the antarctic atmosphere, including Na+ (sodium), NH4 (ammonium), K+ (potassium), Mg2+ (magnesium), Ca2+ (calcium), Cl- (chloride), NO3- (nitrate), and SO4 (sulfate). Chemical analysis also includes methanesulfonic acid (MSA) and nssSO42- (non-sea salt sulfate). The data are available by FTP in ASCII text format and Excel files.

Citing These Data

Mayewski, Paul A., Karl J. Kreutz, Mark Twickler, Sallie Whitlow, and Loren D. Meeker. 2005. Ross Ice Drainage System (RIDS) Glaciochemical Analysis. Boulder, CO: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N5M906KG.

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.

Overview Table

Category Description
Data format Data are available as ASCII text and Excel files.
Spatial coverage Site A: 78°44'S, 116°20'W
Site B: 79°27.66'S, 118°02.68'W
Site C: 80°00.85'S, 119°33.73'W
Temporal coverage

Ice cores are dated as follows:
Site A is from 1506 A.D. to 1996 A.D.
Site B is from 1690 A.D. to 1995 A.D.
Site C is from 1594 A.D. to 1995 A.D.

The cores were collected during the 1995 traverse.

File size RIDS95A.txt is 160 KB.
RIDS95A.xls is 476 KB.
RIDS95B.txt is 60 KB.
RIDS95B.xls is 100 KB.
RIDS95C.txt is 72 KB.
RIDS95C.xls is 220 KB.
Parameter(s) All concentrations are in microequivalents per liter.
Na+   sodium
NH4   ammonium
K+   potassium
Mg2+   magnesium
Ca2+   calcium
Cl-   chloride
NO3-   nitrate
SO4   sulfate
MSA   methanesulfonic acid
nssSO42-   non-sea salt sulfate (Site A only)
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

Paul Mayewski
Karl Kreutz
Climate Change Institute and Department of Earth Sciences
University of Maine
Orono, ME, USA

Mark Twickler
Sallie Whitlow
Loren D. Meeker
Climate Change Research Center
Institute for the Study of Earth, Oceans, and Space
University of New Hampshire
Durham, NH, 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 "Ross Ice Drainage System (RIDS) Late Holocene Climate Variability." National Science Foundation OPP award # 9316564.

2. Detailed Data Description

The RIDS project provides a high-resolution record of the antarctic climate, equivalent to the Greenland Ice Sheet Project 2 (GISP2) ice core. Three ice cores were collected in 1995 using a lightweight dry-drilling operation. Glaciochemical analysis included Na+ (sodium), NH4 (ammonium), K+ (potassium), Mg2+ (magnesium), Ca2+ (calcium), Cl- (chloride), NO3- (nitrate), and SO4 (sulfate) found in the antarctic atmosphere, plus MSA (methanesulfonic acid) and nssSO42- (non-sea salt sulfate). Depth and age relationships were derived from a combination of beta profiles, annual cycles in discrete and continuous chemistry measurements, and volcanic horizons. Chemistry sampling intervals are as follows:

These records are intended to solve a variety of scientific objectives while providing spatial sampling and reconnaissance for future U.S. efforts in West Antarctica. The major objectives for RIDS are to:

  1. Document sub-decadal to century-plus-scale climate variability over the RIDS region.
  2. Characterize major atmospheric (ENSO, cyclogenesis) and oceanic (changes in sea ice distribution and marine productivity) phenomena affecting climate over RIDS (mass balance, temperature, and circulation strength).
  3. Assess how much the environment (atmospheric composition, mass balance, wind strength) over RIDS has changed during the Holocene, and assess differences between sites.
  4. Compare the ice-core-derived RIDS climate record with the GISP2 climate record.
  5. Assess the effects of anthropogenic activity (ozone depletion, pollutant levels, biomass burning, global warming).
  6. Produce a detailed Holocene volcanic history documenting the timing and magnitude of volcanic events affecting the RIDS region.
  7. Investigate possible causes of climate change deduced from the RIDS records.

Format

Data from the RIDS95A, RIDS95B, and RIDS95C ice cores are provided as ASCII text and Excel files.

The data for site A are organized as follows. Dates are given in decimal fractions of the year. Chemical concentrations are in microequivalents per liter.

Column 1: Sample Name
Column 2: Depth (top, meters)
Column 3: Years Before Present
Column 4: Year
Column 5: Na+
Column 6: NH4
Column 7: K+
Column 8: Mg2+
Column n: Ca2+
Column 10: Cl-
Column 11: NO3-
Column12: SO4
Column 13: nssSO42-
Column 14: MSA

The data for sites B and C are organized as follows. Dates are given in decimal fractions of the year. Chemical concentrations are in microequivalents per liter.

Column 1: Sample Name
Column 2: Depth (top, meters)
Column 3: Years Before Present
Column 4: Year
Column 5: Na+
Column 6: NH4
Column 7: K+
Column 8: Mg2+
Column 9: Ca2+
Column 10: Cl-
Column 11: NO3-
Column 12: SO4
Column 13: MSA

File Naming Convention

Text and Excel files are named after the sites where cores were drilled. Site A data are located in "RIDS95A.txt" and "RIDS95A.xls," site B data are located in "RIDS95B.txt" and "RIDS95B.xls," and site C data are located in "RIDS95C.txt" and "RIDS95C.xls."

File Size

RIDS95A.txt is 160 KB.
RIDS95A.xls is 476 KB.
RIDS95B.txt is 60 KB.
RIDS95B.xls is 100 KB.
RIDS95C.txt is 72 KB.
RIDS95C.xls is 220 KB.

Spatial Coverage

SITE A: 78°44'S, 116°20'W, elevation 1804 m, 148 m core drilled, 2 m snow pit sampled

SITE B: 79°27.66'S, 118°02.68'W, elevation 1705 m, 60 m core drilled, 2 m snow pit sampled

SITE C: 80°00.85'S, 119°33.73'W, elevation 1530 m, 60 m core drilled, 2 m snow pit sampled

Temporal Coverage

Ice cores are dated as follows:
Site A is from 1506 A.D. to 1996 A.D.
Site B is from 1690 A.D. to 1995 A.D.
Site C is from 1594 A.D. to 1995 A.D.

The cores were collected during the 1995 traverse.

Parameter or Variable

Parameter Description

The measured parameters include Na+ (sodium), NH4 (ammonium), K+ (potassium), Mg2+ (magnesium), Ca2+ (calcium), Cl- (chloride), NO3- (nitrate), SO4 (sulfate), MSA (methanesulfonic acid), and nssSO42- (non-sea salt sulfate) in microequivalents per liter.

Microequivalents are used for expressing concentrations of ionic substances and assessing what types of compounds the various elements may be traveling as. For example, the compound sodium sulfate (Na2SO4) has one "equivalent" unit of sodium, and two "equivalent" units of sulfate. The conversion between parts per billion and microequivalents is:

ppb * valence charge/molecular weight = microequivalents per liter.

Sample Data Record

The following sample is from "RIDS95B.xls." Dates are given in decimal fractions of the year. Chemical concentrations are in microequivalents per liter.

Sample  Depth (top, meters)  Year BP  Year  Na  NH4  K  Mg  Ca  Cl  NO3  SO4  MSA
b1  0  4  1996  42.78  2.39  1.68  7.03  2.63  90.49  52.28  29.55  6.47
b2  0.02  4.1   1995.9   30.31  1.04  1.22  5.02  1.6  70.26  41.67  20.2  7.78
b3  0.04  4.19   1995.81   34.43  1.1  0.9  5.12  1.91  70.04  44.53  22.47  4.97

3. Data Access and Tools

Data Access

Data are available via FTP.

4. Data Acquisition and Processing

Sensor or Instrument Description

Chemical analysis was performed using a suppressed ion chromatographer.

Data Acquisition Methods

The 1995 field season involved drilling three ice cores and collecting snow pit samples along a 158 km traverse trending 26° (relative to true north) from Byrd Surface Camp. 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 suppressed ion chromatography. SO42- was partitioned into sea salt (ss) and non-sea salt (nss) fractions using standard Na+/SO42- seawater ratios.

Gross ß-activity (total beta radiation emitted from a sample) was measured on 20 cm samples using a gas-flow proportional counter. Maxima in each ß-activity profile are assumed to represent the global peak reached prior to the 1963 Atmospheric Test Ban Treaty, which reached Antarctica during the austral summer 1964/1965. In each core, it is possible to accurately count back to the 1964/1965 chronostratigraphic horizon using summer nssSO42- peaks. Annual layer thickness in both snow pits and cores are therefore calculated based on seasonal nssSO42- cycles, and converted to accumulation rates (b, in gcm-2yr-1) using density profiles (data every 3 cm in snow pits and 1 m in ice cores).

5. References and Related Publications

Kreutz, K.J., P.A. Mayewski, L.D. Meeker, M.S. Twickler, and S. Whitlow. 2000. The effect of spatial and temporal accumulation rate variability in West Antarctica on soluble ion deposition. Geophysical Research Letters 27(16): 2517-2520.

Kreutz, K.J., and P.A. Mayewski. 1999. Spatial variability of Antarctic surface snow glaciochemistry: implications for paleoatmospheric circulation reconstructions. Antarctic Science 11(1): 105-118.

Kreutz, K.J., P.A. Mayewski, M.S. Twickler, and S.I. Whitlow. 1996. Ice core glaciochemical reconnaissance in inland West Antarctica. Antarctic Journal of the U.S. 31(2): 51-52.

6. Document Information

Document Creation Date

7 March 2005

Document Revision Date

18 April 2005

Document Review Date

April 2005

Document URL

http://nsidc.org/data/docs/agdc/nsidc0266_mayewski/index.html