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

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 sizes are 9 KB and 32 KB.

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:

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:

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:

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.

Snow samples were collected during the 2003 austral summer.

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

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).

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.

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.

Antarctic Glaciological Data Center (AGDC) at NSIDC