World Data Centre for Greenhouse Gases (WDCGG)

Category	Air sampling observation
Sampling Type	flask
Sampling Height/Depth
Sampling and Analysis Frequency	Several times a month
Sampling Environment
Measurement Method	Gas Chromatography (FID)
Current status and history of Instruments	GC-FID
Description of Instruments	Carle (part of Chandler Engineering, OK, USA) Series 400
Time Zone	UTC
Data Period	1991-03-01 - 2008-12-15
Data Type	event, monthly
Parameter detail
Other Descriptions for Sampling and Analyses	SAMPLING: The data have been obtained from flask air samples returned to GASLAB for analysis. The flasks are of 6 types, 4 of which are the property of CSIRO (items a-d below) and 2 of which are the property of Environment Canada for air sampling at the Canadian sites, Alert, Estevan Point and Fraserdale (items e and f): (a) glass 0.5 litre, sealed with two stopcocks fitted with PTFE, PFA or Viton O-rings (flask identifier prefix “G050”), (b) glass 5.0 litre, sealed with two stopcocks fitted with PTFE O-rings (“G500”), (c) glass 0.8 litre, sealed with two stopcocks fitted with PTFE or PFA O-rings (“G080”), (d) electropolished stainless steel 1.6 litre “Sirocans” fitted with two stainless steel valves manufactured by either Nupro or Hoke (“S160”), (e) glass 2.0 litre sealed with a single stopcock fitted with a Viton O-ring (“F”, “FF”, “FA”, “FE”, “EP”, ALT”) or (f) glass 2.0 litre sealed with two stopcocks fitted with Viton O-rings (“M1”, “S”, “P2”, “TEMP”). Experiments carried out to test for changes in sample CO₂ mixing ratio during storage have shown significant drifts in some flask types over test periods of several months to years (Cooper et al., 1999) and can be largely attributed to permeation through O-rings (Langenfelds, 2002; Sturm et al., 2004). Corrections are applied to network data according to flask type, sample and ambient pressure. Typical sample storage times range from days to weeks for some sites (e.g. Cape Grim, Aircraft) to as much as 1 year for Macquarie Island and the Antarctic sites. ANALYSIS: Samples were analysed by gas chromatography with flame ionisation detection after methanization of CO₂ to CH₄. One Carle gas chromatograph, labelled “Carle-3” (C3) was used over the length of the record. Data are reported here in the WMOX2007 CO₂ mole fraction calibration scale. Further details are provided elsewhere of CSIRO’s global sampling network, sampling and analytical techniques (Francey et al., 1996), and measurement uncertainty (Francey et al., 2003).
Scientific Aim	To provide high quality measurements of atmospheric composition (the major long-lived greenhouse gases, and some related species) that can be used in studies of global biogeochemical cycles, particularly the global carbon cycle. To make it possible to seamlessly merge these measurements with those made by other organisations for purposes of modelling and interpretation.
Supporting Contributor(s)
Last update	2009-09-02
Situation	ongoing

Category	Parameter	Country/Territory	Contributor

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This site is maintained by the Japan Meteorological Agency
in cooperation with the World Meteorological Organization
(Created : 2001/07/02 Modified : 2010/09/02)

WMO World Data Centre for Greenhouse Gases
c/o Japan Meteorological Agency
1-3-4, Otemachi, Chiyoda-ku
Tokyo 100-8122, Japan

Tel:	+81-3-3287-3439
Fax:	+81-3-3211-4640
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