Intercalibration experiment of methane standard gas scale between NOAA/CMDL and MRI/GRL.
Intercalibration experiment of methane standard gas scale between NOAA/CMDL and MRI/GRL.
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NOAA/CMDL 与 MRI/GRL 甲烷标准气标尺互标实验
DOI：
10.2467/mripapers.44.45
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发表时间：
1993
影响因子：
--
通讯作者：
秀和 松枝
中科院分区：
文献类型：
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作者：
秀和 松枝
研制了一套GC/FID自动分析系统，用于标准气体中甲烷混合比的测定，平均精密度为± 0.12%。对5个重量标准品的GC/FID分析表明，它们的甲烷标度稳定，内部一致。然而，用于这些标准的稀释空气含有少量甲烷，估计为35.5 ppb。因此，我们的MRI/GRL量表针对稀释空气中的甲烷杂质进行了校正。 根据MRI/GRL标度，为相互校准实验准备的铝筒中干燥天然空气的甲烷混合比确定为1.7545±0.0015 ppm。这一混合比比NOAA/CMDL指定的高23.0 ppb。这一差异表明，在比较两个实验室的甲烷数据时，需要考虑到NOAA/CMDL和MRI/GRL尺度之间23.0 ppb的偏移。
We developed an automated GC/FID analysis system to determine methane mixing ratios of standard gases with a mean precision of ±0.12%. The GC/FID analysis of five gravimetric standards showed that their methane scale was stable and internally consistent. However, the diluent air for these standards had a small amount of methane, which was estimated to be 35.5 ppb. Thus, our MRI/GRL scale was corrected for methane impurity in the diluent air. The methane mixing ratio of dry natural air in an aluminum cylinder prepared for the intercalibration experiment was determined to be 1.7545±0.0015 ppm on the basis of the MRI/GRL scale. This mixing ratio was higher by 23.0 ppb than that assigned by NOAA/CMDL. This difference indicated that the offset of 23.0 ppb between NOAA/CMDL and MRI/GRL scales will need to be taken into account when methane data from both laboratories are compared.