Estimating regional fluxes of CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; and CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt; using space-borne observations of XCH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;: XCO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;
Atmospheric chemistry and physics