 |
| Titel |
Results from the International Halocarbons in Air Comparison Experiment (IHALACE) |
| VerfasserIn |
B. D. Hall, A. Engel, J. Mühle, J. W. Elkins, F. Artuso, E. Atlas, M. Aydin, D. Blake, E.-G. Brunke, S. Chiavarini, P. J. Fraser, J. Happell, P. B. Krummel, I. Levin, M. Loewenstein, M. Maione, S. A. Montzka, S. O'Doherty, S. Reimann, G. Rhoderick, E. S. Saltzman, H. E. Scheel, L. P. Steele, M. K. Vollmer, R. F. Weiss, D. Worthy, Y. Yokouchi |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1867-1381
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 2 ; Nr. 7, no. 2 (2014-02-10), S.469-490 |
| Datensatznummer |
250115598
|
| Publikation (Nr.) |
 copernicus.org/amt-7-469-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| The International Halocarbons in Air Comparison Experiment (IHALACE) was
conducted to document relationships between calibration scales among various
laboratories that measure atmospheric greenhouse and ozone depleting gases.
This study included trace gases such as chlorofluorocarbons (CFCs),
hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs), as well as
nitrous oxide, methane, sulfur hexafluoride, very short-lived halocompounds,
and carbonyl sulfide. Many of these gases are present in the unpolluted
atmosphere at pmol mol−1 (parts per trillion) or nmol mol−1
(parts per billion) levels. Six stainless steel cylinders containing natural
and modified natural air samples were circulated among 19 laboratories.
Results from this experiment reveal relatively good agreement (within a few
percent) among commonly used calibration scales. Scale relationships for some
gases, such as CFC-12 and CCl4, were found to be consistent with those
derived from estimates of global mean mole fractions, while others, such as
halon-1211 and CH3Br, revealed discrepancies. The transfer of
calibration scales among laboratories was problematic in many cases, meaning
that measurements tied to a particular scale may not, in fact, be compatible.
Large scale transfer errors were observed for CH3CCl3 (10–100%)
and CCl4 (2–30%), while much smaller scale transfer
errors
(< 1%) were observed for halon-1211, HCFC-22, and HCFC-142b. These
results reveal substantial improvements in calibration over previous
comparisons. However, there is room for improvement in communication and
coordination of calibration activities with respect to the measurement of
halogenated and related trace gases. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|