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Data Set ID:
NSIDC-0394

Atmospheric Mixing Ratios of Hydroperoxides above the West Antarctic Ice Sheet, Version 1

This data set contains atmospheric mixing ratios of hydrogen peroxide and methylhydroperoxide at 21 sites on the West Antarctic Ice Sheet (WAIS) were obtained from 2000 to 2003 during the US International Trans-Antarctic Scientific Expedition (US ITASE) deployments. Sample location from the WAIS region (76-90ºS / 84-124ºW) were approximately 100-300 km apart and correspond to US ITASE ice core sites. At each site, ambient air from 1 m above the snow surface was sampled between two to five days. Atmospheric hydroperoxides (ROOH) were continuously scrubbed from the sample air with a glass coil scrubber and subsequently quantified using a fluorescence detection method.

Data are available via FTP as ASCII text files (.txt).

Geographic Coverage

Parameter(s):
  • Glaciers/Ice Sheets > Firn
  • Glaciers/Ice Sheets
  • Glaciers/Ice Sheets > Ice Sheets
  • Snow/Ice
  • Snow/Ice > Snow/Ice Chemistry
Spatial Coverage:
  • N: -76, S: -90, E: -84, W: -124

Spatial Resolution: Not Specified
Temporal Coverage:
  • 20 November 2000 to 15 January 2003
Temporal Resolution: Not specified
Data Format(s):
  • ASCII Text
Platform(s) FIELD INVESTIGATION, FIELD SURVEYS, LABORATORY
Sensor(s): FLUORESCENCE SPECTROSCOPY, GAS SENSORS
Version: V1
Data Contributor(s): Roger Bales, Markus Frey, Joseph McConnell
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.

Bales, R., M. Frey, and J. McConnell. 2009. Atmospheric Mixing Ratios of Hydroperoxides above the West Antarctic Ice Sheet, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: http://dx.doi.org/10.7265/N5PZ56RS. [Date Accessed].

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Detailed Data Description

Format

Data are available as ASCII text files (.txt).

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File and Directory Structure

Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/AGDC/bales_nsidc_0394/ directory. The directory contains a folder with four data files in ASCII text format, and a metadata file, site_info.txt, which lists site information for each data file. Descriptions of the column headings in the site_info.txtfile are listed in Table 1.

Table 1.Column Description for the site_info.txt file
Column Description
site Site ID number
lat, °S Latitude
long, °W Longitude
elev, m Site elevation, meters above mean sea level
T, °C Mean site temperature, ºC
start, GMT Start sampling, GMT decimal year
stop, GMT Stop sampling, GMT decimal year
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File Naming Convention

Files are named according to the following convention and as described in Table 2:

ITyy_i.txt

where:

Table 2. File Naming Convention
Parameter Description
ITyy Measurement location and sampling intervals, as described in site_info.txt file
_i Measurement number
.txt File extension for ASCII text files
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File Size

Files in this data set range in size from 8 KB to 126 KB .

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Volume

The total volume of the data set is less than 0.124 MB.

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Spatial Coverage

Data were collected along the United States International Trans-Antarctic Scientific Expedition (US ITASE) traverse route.

Southernmost Latitude: 90° S
Northernmost Latitude: 76° S
Westernmost Longitude: 124° W
Easternmost Longitude: 84° W

Spatial Coverage Map

Map: Location of US ITASE traverses

Map: Location of US ITASE traverses
The map above shows the traverse routes of the United States portion of the International Trans-Antarctic Scientific Expedition (US ITASE).

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Temporal Coverage

Data in this collection were obtained 20 November 2000 to 15 January 2003, Antarctic summers only.

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Parameter or Variable
Table 3. Parameters in the Profile Data Files
Column Number Description
1 Measurement date, GMT decimal year
2 10 min. average hydrogen peroxide (H2O2), parts per trillion by volume (pptv)
3 1 standard deviation H2O2, pptv
4 Number of 2.5 min intervals used for average
5 10 min. average methylhydroperoxide (MHP), pptv
6 1 standard deviation MHP, pptv
7 Number of data points (chromatograms) used for average

Sample Data Record

The following example shows sample data from the IT01.txt file:

2001.904871 459 16 3 371 0 1
2001.904909 471 19 5 296 0 1
2001.904928 444 25 3 392 0 1
2001.904947 423 11 4 370 0 1
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Software and Tools

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Data Acquisition and Processing

Theory of Measurements

Researchers conducted measurements at each site along the traverse. Ambient air from 1 meter above the snow surface was sampled between two to five days. Atmospheric hydroperoxides were continuously scrubbed from the sample air with a glass coil scrubber and subsequently quantified using a fluorescence detection method.

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Data Acquisition Methods

Atmospheric hydroperoxides were continuously scrubbed from the sample air with a glass coil scrubber and subsequently quantified using a fluorescence detection method. The two-channel instrument deployed measured total peroxides continuously (Channel 1) and H2O2 & MHP using a HPLC method (Channel 2). At each site ambient air from 1 meter above the snow surface was sampled between two to five days. Atmospheric hydroperoxides were continuously scrubbed from the sample air with a glass coil scrubber and subsequently quantified using a fluorescence detection method. 
 

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Sensor or Instrument Description

The two-channel instrument measured total peroxides continuously (Channel 1), and H2O2 and Methylhydroperoxide (MHP) using a High Pressure Liquid Chromatography (HPLC) method (Channel 2). For a detailed instrument description see: Frey, et al. 2005.

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Limits of Detection

More details on database development (experimental method, data processing) and discussion of the results are published in Frey, et al., 2005.

Precision for H202 was less than 20pptv MHP (<60pptv 2). Limits of detection for peroxide and MHP are listed below.

Table 4. Limits of Detection for H2O2 and MHP
Parameter Year Detection Limit
H202 2000-2001
2001-2002
<50 pptv
H202 2002-2003 <30 pptv
MHP 2001-2002 <150 pptv
MHP 2002-2003 <30pptv

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References and Related Publications

Contacts and Acknowledgments

Dr. Roger Bales 
University of California
School of Engineering 
PO Box 2039 
Merced, California 95344

Dr. Markus Frey 
University of California 
School of Engineering 
PO Box 2039 
Merced, California 95344

Dr. Joseph McConnell
Hydrologic Sciences Division
Desert Research Institute
2215 Raggio Parkway 

Acknowledgments: 

This research was supported by NSF OPP grant 9814810 .

Document Information

DOCUMENT CREATION DATE

23 April 2009

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