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Data Set ID:
NSIDC-0519

Light Absorption Coefficients for Soluble Species in Snow, Dome C, Antarctica, Version 1

This data set contains light absorption coefficients for soluble chromophores (light-absorbing chemicals) and concentrations of hydrogen peroxide (HOOH) and nitrate (NO3-) in ten snow samples that were collected in 2003 at Dome C, Antarctica.

Data are available via FTP.

Geographic Coverage

Spatial Coverage:
  • N: -75.1, S: -75.1, E: -123.3, W: -123.3

Spatial Resolution: Not Specified
Temporal Coverage:
  • 1 January 2003 to 31 January 2003
Temporal Resolution: Not specified
Parameter(s):
  • Glaciers/Ice Sheets
  • Snow/Ice
  • Snow/Ice > Snow/Ice Chemistry
Platform(s) LABORATORY
Sensor(s): HPLC, ION CHROMATOGRAPHS, SPECTROPHOTOMETERS
Data Format(s):
  • ASCII Text
Version: V1
Data Contributor(s): Cort Anastasio, Tony Robles

Data Citation

As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

Cort Anastasio and Tony Robles 2012. Light Absorption Coefficients for Soluble Species in Snow, Dome C, Antarctica, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: http://dx.doi.org/10.7265/N5MS3QP0. [Date Accessed].

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Detailed Data Description

This data set contains light absorption coefficients for soluble chromophores (light-absorbing chemicals) and concentrations of hydrogen peroxide (HOOH) and nitrate (NO3-), in ten snow samples that were collected in 2003 near Concordia Research Station at Dome C, Antarctica.

Format

The data set consists of two tab-delimted ASCII text files.

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File and Directory Structure

Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/AGDC/nsidc0519_anastasio_V01/ directory. This directory contains two data files, Sample_Info.txt and Light_Absorption.txt, and a readme file.

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File Size

File sizes are 9 KB and 32 KB.

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Sample Data

Sample_Info.txt contains concentrations of HOOH and NO3- and site-specific details about the snow samples. Each row represents one sample. Table 2 provides descriptions for the column headings in Sample_Info.txt:

Table 2. Column heading descriptions for Sample_Info.txt
Column Heading Description
Original_ID Original sample name assigned by University of Bern
UCD_ID Sample name assigned by University of California, Davis
Collection_time Time sample was collected (local time)
Depth_top Depth at top of sample (cm)
Depth_bottom Depth at bottom of sample (cm)¹
HOOH Hydrogen peroxide concentration (µmol per liter of melted sample)
NO3 Nitrate concentration (µmol per liter of melted sample)
LCW_path Optical path-length of liquid core waveguide (m)
Lat Latitude of sample location (degrees south)
Long Longitude of sample location (degrees east)
Elevation Elevation of sample location (m)
Clean_Area Indicates whether sample was collected in a designated clean area (Y/N)
¹If not recorded, a value of 2 cm was estimated for surface samples.

The following is an excerpt from Sample_Info.txt:

Light_Absorption.txt contains the light absorption coefficients for each sample at wavelengths between 240 nm and 640 nm. Table 3 below provides descriptions for the parameters in Light_Absorption.txt:

Table 3. Parameter descriptions for Light_Absorption.txt
Parameter Description
Wavelength Measurement wavelength (nm)
Absorption Coefficient Absorption (extinction) coefficient (m-1) at the given measurement wavelength¹. Column headings correspond to UCD_ID sample names in Sample_Info.txt.

¹The relationship between absorption and extinction coefficients is detailed in the Quality Assessment section below.


The following is an excerpt from Light_Absorption.txt:

Figure 1 is a plot of the light absorption coefficients for one sample in Light_Absorption.txt:

Light Absorption
Figure 1. Light Absorption Coefficients for One Snow Sample in Light_Absorption.txt.

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Spatial Coverage

All samples were collected near Concordia Research Station at Dome C, Antarctica, at approximately 75.1° S, 123.3° W. Sample_Info.txt contains additional site-specific details for each sample.

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Temporal Coverage

Snow samples were collected during the 2003 austral summer.

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Software and Tools

Quality Assessment

Absorption coefficients have an uncertainty of approximately 0.002 m-1.

In the original treatment of these data (Anastasio, C. and T. Robles, 2007) the investigators calculated absorption coefficients by subtracting an estimated scattering component from the measured extinction coefficients. The investigators subsequently concluded that scattering in their samples, which were filtered, was negligible and as such the measured extinction coefficients are essentially absorption coefficients.

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Data Acquisition and Processing

Snow samples were collected during the summer of 2003. Although the collection dates were not recorded, samples were likely obtained in January.

All analyses were performed in the Anastasio Research Group laboratory of The University of California, Davis. Nitrate concentrations were measured using ion chromatography with conductivity detection. The detection limit was 500 nanomolar with a precicion of approximately 5 percent. Hydrogen peroxide concentrations were measured using fluorescence high-pressure liquid chromatography (HPLC) with post-column derivatization. The HPLC detection limit was 10 nanomolar with a precision of approximately 3 percent.

Absorption coefficients were measured with a custom-built, long path (1.20 m or 1.17 m) liquid-core waveguide placed in a Shimadzu UV-Vis spectrophotometer. The detection limit of the instrument, expressed as an absorption coefficient, is approximately 0.002 m-1. As such, the uncertainy in each absorption coefficient is approximately 0.002 m-1. For additional information about sample processing and analyses, see Anastasio, C. and T. Robles (2007) and Robles, T. et al. (2006).

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References and Related Publications

Contacts and Acknowledgments

Dr. Cort Anastasio
University of California, Davis
Department of Land, Air, and Water Resources
1 Shields Avenue
Davis, CA 95616

Dr. Tony Robles
University of California, Davis
Department of Land, Air, and Water Resources
1 Shields Avenue
Davis, CA 95616

Acknowledgements: 

This research was supported by National Science Foundation Office of Polar Programs grant number 0230288. The investigators also wish to thank Karen Guldbaek Schmidt, Manuel Hutterli, and Bernhard Stauffer for collecting snow samples and David Paige for manufacturing the LCW adapter assembly.

Document Information

DOCUMENT CREATION DATE

June 2012

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