A combustion setup to precisely reference δ&lt;sup&gt;13&lt;/sup&gt;C and δ&lt;sup&gt;2&lt;/sup&gt;H isotope ratios of pure CH&lt;sub&gt;4&lt;/sub&gt; to produce isotope reference gases of δ&lt;sup&gt;13&lt;/sup&gt;C-CH&lt;sub&gt;4&lt;/sub&gt; in synthetic air
Atmospheric measurement techniques