Performance assessment of the mobile G4301 Cavity Ring-Down Spectroscopy analyzer for atmospheric CO2, CH4 and H2O measurements
Authors: Lienhardt Luc , Laurent Olivier , E. G. Hofmann Magdalena 
Published: March 2022

&lt;p&gt;Carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) and methane (CH&lt;sub&gt;4&lt;/sub&gt;) are the most important greenhouse gases, and there is an increasing need to measure these greenhouse gases with mobile measurement devices. Picarro&amp;#8217;s G4301 Cavity Ring-Down Spectroscopy (CRDS) analyzer is a high-performance, light-weight, portable, battery-powered gas concentration analyzer that has enabled real-time measurements of CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; in challenging environments in the field of ecosystem [1]&amp;#8211;[3], soil science [4] , glaciology [5], limnology [6] and indoor air quality [7]. Here we evaluate the performance of this portable greenhouse gas analyzer for atmospheric measurements, and discuss data obtained with this analyzer during balloon flights. &amp;#160;&lt;/p&gt;&lt;p&gt;The performance of the G4301 analyzer was assessed at the Metrology Laboratory (MLab) that is part of the Atmospheric Thematic Center of ICOS. The MLab regularly tests greenhouse gas analyzers that are used within the European monitoring network ICOS (Integrated Carbon Observation System). We will present CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; performance data on the continuous measurement repeatability (CMR), the short-term repeatability (STR), the long-term repeatability (LTR), the ambient temperature sensitivity, the inlet pressure sensitivity, and the built-in water vapor correction. We will discuss these findings in light of measurement requirements for different atmospheric applications.&lt;/p&gt;&lt;p&gt;To assess the performance of the analyzer in mobile field measurements, the G4301 was deployed at several balloon flights over Paris.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;[1]&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; J. H. Matthes, A. K. Lang, F. V. Jevon, and S. J. Russell, &amp;#8220;Tree stress and mortality from emerald ash borer does not systematically alter short-term soil carbon flux in a mixed northeastern U.S. forest,&amp;#8221; &lt;em&gt;Forests&lt;/em&gt;, vol. 9, no. 1, pp. 1&amp;#8211;16, 2018.&lt;/p&gt;&lt;p&gt;[2]&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; L. Kohl &lt;em&gt;et al.&lt;/em&gt;, &amp;#8220;Technical note: Interferences of volatile organic compounds (VOCs) on methane concentration measurements,&amp;#8221; &lt;em&gt;Biogeosciences&lt;/em&gt;, vol. 16, no. 17, pp. 3319&amp;#8211;3332, 2019.&lt;/p&gt;&lt;p&gt;[3]&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; L. Jeffrey &lt;em&gt;et al.&lt;/em&gt;, &amp;#8220;Are methane emissions from mangrove stems a cryptic carbon loss pathway? Insights from a catastrophic forest mortality,&amp;#8221; no. June, 2019.&lt;/p&gt;&lt;p&gt;[4]&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; L. L. Chai &lt;em&gt;et al.&lt;/em&gt;, &amp;#8220;A methane sink in the Central American high elevation p&amp;#225;ramo: Topographic, soil moisture and vegetation effects,&amp;#8221; &lt;em&gt;Geoderma&lt;/em&gt;, vol. 362, no. April 2019, p. 114092, 2020.&lt;/p&gt;&lt;p&gt;[5]&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; J. R. Christiansen and C. J. J&amp;#248;rgensen, &amp;#8220;First observation of direct methane emission to the atmosphere from the subglacial domain of the Greenland Ice Sheet,&amp;#8221; &lt;em&gt;Sci. Rep.&lt;/em&gt;, vol. 8, no. 1, p. 16623, Dec. 2018.&lt;/p&gt;&lt;p&gt;[6]&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; J. A. Villa &lt;em&gt;et al.&lt;/em&gt;, &amp;#8220;Methane and nitrous oxide porewater concentrations and surface fluxes of a regulated river,&amp;#8221; &lt;em&gt;Sci. Total Environ.&lt;/em&gt;, vol. 715, p. 136920, 2020.&lt;/p&gt;&lt;p&gt;[7]&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; Z. Merrin and P. W. Francisco, &amp;#8220;Unburned Methane Emissions from Residential Natural Gas Appliances,&amp;#8221; &lt;em&gt;Environ. Sci. Technol.&lt;/em&gt;, vol. 53, no. 9, pp. 5473&amp;#8211;5482, May 2019.&lt;/p&gt;