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

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.

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

Citing These Data

The following example shows how to cite the use of this data set in a publication.

Anastasio, C. and T. Robles. 2012. Light Absorption Coefficients for Soluble Species in Snow, Dome C, Antarctica. Boulder, Colorado USA: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N5MS3QP0.

Overview

Platform

Ground-based Observation

Sensor

Liquid Core Waveguide (LCW) Spectrophotometer
Ion Chromatography
Fluorescence High-pressure Liquid Chromatography

Spatial Coverage

Dome C, Antarctica:

Northernmost Latitude: 75.1° S
Southernmost Latitude: 75.1° S
Westernmost Longitude: 123.3° W
Easternmost Longitude: 123.3° W

Temporal Coverage

Austral Summer, 2003

Parameters

Wavelength (nm)
Absorption Coefficient (m-1)

Data Format

Tab-delimited ASCII text (.txt)

Metadata Access

View Metadata Record

Data Access

FTP

1. Contacts and Acknowledgments

Investigators

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

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 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.

2. 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.

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.

File Size

File sizes are 9 KB and 32 KB.

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:

sample data from Light_Absorption.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:

sample data from Sample_Info.txt


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

plot of light absorption coefficients for one sample in Light_Absorption.txt
Figure 1: Light Absorption Coefficients for One Snow Sample in Light_Absorption.txt.

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.

Temporal Coverage

Snow samples were collected during the 2003 austral summer.

3. Data Access

Files may be downloaded via FTP and accessed using standard spreadsheet software.

4. 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%. 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%.

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).

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.

5. References and Related Publications

Anastasio C. and T. Robles. 2007. Light Absorption by Soluble Chemical Species in Arctic and Antarctic Snow, Journal of Geophysical Research, 112(D24304), doi: 10.1029/2007JD008695.

Robles, A., D. Paige, and C. Anastasio. 2006. Lens-Coupled Liquid Core Waveguide for Ultraviolet-Visible Absorption Spectroscopy, Review of Scientific Instruments, 77(073103), doi: 10.1063/1.2219973.

Related Data Collections

6. Document Information

Acronyms and Abbreviations

The acronyms used in this document are listed in Table 4.

Table 4. Acronyms and Abbreviations
Acronym Description
LCW Liquid-Core Waveguide
HPLC High-Pressure Liquid Chromatography
HOOH Hydrogen Peroxide
NO3- Nitrate
UCD_ID University of California, Davis ID
AGDC Antarctic Glaciological Data Center
NSIDC National Snow and Ice Data Center
ASCII American Standard Code for Information Interchange
FTP File Transfer Protocol
PDF Portable Document Format

Document Creation Date

June 2012

Document URL

http://nsidc.org/data/docs/agdc/nsidc0519-anastasio/index.html