Documentation for Methane Measurements from the GISP2 and Siple Dome Ice Cores, Version 1

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Detailed Data Description


Data are in Microsoft Excel (.xls) format.

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File and Directory Structure

Data are available on the FTP site in the directory. Within this directory, there is one data file, and one readme file in text format (.txt).

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File Naming Convention

The data file, Brook_Holocene_CH4.xls, contains methane data from the Holocene portion of the GISP2 and Siple Dome ice cores.

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The total volume of the data set is 44 KB.

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Spatial Coverage

The file contains data from the Siple Dome ice core, drilled in Antarctica, and the GISP2 ice core, from Greenland. The geographic locations of the two ice cores are listed below:

Siple Dome:
Southernmost Latitude: 81.65° S
Northernmost Latitude: 81.65° S
Westernmost Longitude: 148.81° W
Easternmost Longitude: 148.81° W

Southernmost Latitude: 73.58° N
Northernmost Latitude: 73.58° N
Westernmost Longitude: 38.4° W
Easternmost Longitude: 38.4° W

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Temporal Coverage

Measurements were made between 2007 and 2009. The age range of the samples is 0 to 11.7 thousand years (ka) for GISP2 and 0 to 10.9 ka for Siple Dome.

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Parameter or Variable

Measurement depths range from 55.7 to 598.39 meters below the surface (mbs) for the Siple Dome ice core, and 95.98 to 1695.35 mbs for the GISP2 ice core.

Parameter Description

The measurements contain depth in meters below surface, gas age in thousands of years (ka), and methane concentration, in parts per billion (ppb).

Sample Data Record

GISP2 Ice Core Siple Dome Ice Core
Mid Depth 
Below Surface (m)
Methane Concentration (ppb) Meese/Sowers 
Gas Age (ka)
Mid Depth Below Surface (m) Methane Concentration (ppb) Gas Age (ka)
(Brook et al., 2005)
95.98 910.7 0.03 55.7 1015.9 0.08059
99.24 894.0 0.05 60.35 865.1 0.11929
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Software and Tools

Software and Tools

Data are accessible using spreadsheet software.

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Data Acquisition and Processing

Measurements were made relative to the NOAA04 methane concentration scale using a working standard internally clailbrated to NOAA certified air standards. Concentrations are corrected for gravitational fractionation and solubility effects in the melt-refreeze extraction. The time scale used was the GISP2: Mees/Sowers Time Scale. The method of construction of the Siple Dome time scale provided here is described in Brook et al., 2005.

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References and Related Publications

Contacts and Acknowledgments

Dr. Edward Brook
Department of Geosciences
104 Wilkinson Hall
Oregon State University
Corvallis, OR 97330


This research was supported by National Science Foundation (NSF) Office of Polar Programs (OPP) grant number 0520523.

Document Information

Document Creation Date

8 December 2009