Consistent regional fluxes of CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt; and CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; inferred from GOSAT proxy XCH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;:XCO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; retrievals, 2010–2014