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.
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.
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: 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:
- RIDS95A core: 3 cm in upper 60 m, 60 cm from 60 to 150 m
- RIDS95B core: 3 cm in upper 20 m, 30 cm from 20 to 60 m
- RIDS95C core: 3 cm in upper 20 m, 25 cm from 20 to 60 m
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:
- Document sub-decadal to century-plus-scale climate variability over the RIDS region.
- 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).
- Assess how much the environment (atmospheric composition, mass balance, wind strength) over RIDS has changed during the Holocene, and assess differences between sites.
- Compare the ice-core-derived RIDS climate record with the GISP2 climate record.
- Assess the effects of anthropogenic activity (ozone depletion, pollutant levels, biomass burning, global warming).
- Produce a detailed Holocene volcanic history documenting the timing and magnitude of volcanic events affecting the RIDS region.
- 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
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