International comparison CCQM-P41 Greenhouse gases. 2. Direct comparison of primary standard gas mixtures
| Autor: | Agata Rakowska, E Dlugokencky, Freek N C Brinkmann, Kenji Kato, Laurie Besley, R Francey, Martin J. T. Milton, Michela Sega, Jin Seog Kim, Alejandro Pérez Castorena, Frank Guenther, Mile Arnautovic, Hans-Joachim Heine, Teresa Lopez Esteban, Adriaan M H van der Veen |
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| Rok vydání: | 2006 |
| Předmět: | |
| Zdroj: | Metrologia. 44:08003-08003 |
| ISSN: | 1681-7575 0026-1394 |
| Popis: | In this second part of this study, primary standard gas mixtures (PSMs) as used for calibrations for the greenhouse gases carbon dioxide and methane have been compared. The nominal amount-of-substance fraction levels were 365 µmol/mol for carbon dioxide and 1.8 µmol/mol for methane. The matrix was synthetic air, simulated by a mixture of nitrogen, oxygen (209 mmol/mol) and argon (9.3 mmol/mol). The measurements took place in the spring of 2003. In the protocol, it was foreseen to have the PSMs produced for this study in a small range, enabling regression analysis on the data to assess the consistency of the gas mixtures. The direct comparison of the PSMs shows agreement for carbon dioxide at 365 µmol/mol nominal within 0.52 µmol/mol (0.14% relative) standard uncertainty. One cylinder lies between the 95% and 99% boundaries of the regression line, and after removing this cylinder from the dataset the standard deviation of the x-residuals reduces to 0.18 µmol/mol (0.05% relative). This value for the standard deviation is substantially greater than the stated standard uncertainties for several cylinders. The standard deviation of the x-residuals for methane at 1.8 µmol/mol nominal is 0.011 µmol/mol. Main text. To reach the main text of this paper, click on Final Report. The final report has been peer-reviewed and approved for publication by the CCQM. |
| Databáze: | OpenAIRE |
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