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| 
Summit
-VOCs-
| Observation |
| Category |
: |
Air sampling observation |
| Situation |
: |
ongoing |
| Time zone |
: |
Local time -2 |
| Sampling |
| Sampling height |
: |
10 |
| Description |
: |
continuous |
| Sampling and analysis frequency |
: |
Times are starting times of sample prefocusing collection period. Sample collection periods varied between 10 min to 50 min. |
| Sampling environment |
: |
|
| Description for sampling analysis |
: |
Instrument is located in TAWO building at Summit. Air is continuously brought in through a heated sampling line with particle filter inlet on the adjacent 15 m met tower. The instrument draws samples through a short piece of tubing that tees into the purged sampling line. |
| Instrument and Analysis |
| Measurement method |
: |
Gas Chromatography (FID) |
| Current status and history of instrument |
: |
Instrument was deployed 2008 - 2010, then removed, and reinstalled a and measurements were resumed, with addition of methane monitoring, in spring of 2012. |
| Description of instrument |
: |
Custom-built inlet system for sample drying and preconcentration. Focusing system relies on multi-stage solid adsorbent microtrap. Separation is by gas chromatography on Al3O3 PLOT column. |
| Calibration |
| Current scale employed in the measurement |
: |
Series of quantitative compressed air gas standards. |
| Measurement calibration |
: |
Response factors are monitored and graphed for the entire year. Drifts in instrument response are typically low, less than 5 % per year. |
| Scale and calibration(treasability) |
: |
Two compressed air standards are injected regularly. These standards are rotated between our lab in Boulder and the field site to check for drifts in analyte mole fractions. |
| Data Processing |
| Measurement unit |
: |
ppb |
| Data processing |
: |
Chromatograms are processed manually performing peak integration. Detector response factors are calculated from regular analyses of quantitative calibration standards. Compound mole fractions are calculated from compound-specific detector response factors. Blank values are subtracted for benzene and toluene only. |
| Processing for averaging |
: |
Processing for Hourly Data:
n/a
Processing for Daily Data:
n/a
Processing for Monthly Data:
n/a |
| Data flag |
: |
Data below the detection limit were flagged "BDL" and substituted with values reflecting 1/2 of the estimated detection limit.
Values flagged "NC" had chromatograms that were noisy, but still had measurable peaks. |
| Data remarks |
: |
No data remarks. |
| Other Information |
| Scientific aim |
: |
Investigate seasonal cycles, pollution transport events, interannual variability, long-term trends of VOC in the remote Arctic. |
| Reference |
: |
Tanner D., Helmig D., Hueber J., and Goldan P. (2006) A gas chromatography system for the automated, unattended, and cryogen-free monitoring of C2 to C6 non-methane hydrocarbons in the remote troposphere. J. Chrom. 1111, 76-88.
Pollmann J., Helmig D., Hueber J., Tanner D., and Tans P. (2006) Evaluation of adsorbent materials for cryogen-free trapping-one stage-GC analysis of atmospheric C2-C6 non-methane hydrocarbons. J. Chrom., 1134, 1-15.
Kramer L.J., Helmig D., Burkhart J.F., Stohl A., Oltmans S., and Honrath R.E. (2014) Seasonal variability of atmospheric nitrogen oxides and non-methane hydrocarbons at the GEOSummit station, Greenland. Atmos. Chem. Phys. Discuss. 13817-13867.
Helmig D., Petrenko V., Martinerie P., Witrant E., Röckmann T., Zuiderweg A., Holzinger R., Hueber J., Thompson C., White J.W.C., Sturges W., Baker A., Blunier T., Etheridge D., Rubino M., and Tans P. (2014) Reconstruction of Northern Hemisphere 1950 – 2010 atmospheric non-methane hydrocarbons. Atmos. Chem. Phys. 14, 1463-1483, doi:10.5194/acpd-14-1463-2014.
Helmig D., Stephens C.R., Caramore J., and Hueber J. (2013) Seasonal behavior of non-methane hydrocarbons in the firn air at Summit, Greenland. Atmos. Environ., 85, 234-246. |
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| submitted by Institute of Arctic and Alpine Research, University of Colorado |
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