COMPARATIVE STUDY ON THE PRECISION OF GREENHOUSE GAS ANALYZERS BASED ON LICOR-830 AND PICARRO G2301
In the process of coping with climate change and realizing carbon peaking and carbon neutrality goals,high-precision observations of greenhouse gases are required.However,relatively few studies have been conducted in laboratories on quantifying the precision differences of different observation systems.In this research,the LICOR-830 CO2 gas analyzer based on non-dispersive infrared absorption method and the Picarro G2301 CO2/CH4/H2 O gas analyzer based on cavity ring-down spectroscopy method were selected to observe the three traceable standard CO2 gases and conduct repeatability tests,drift tests,target calibration gas tests.The accuracy of the measured concentration was compared and analyzed.The test result are as follows:1)Repeatability test:the precision of LICOR-830 is about 0.4 ppm,and the precision of Picarro G2301 is about 0.04 ppm.There is one order of magnitude difference between them.2)Drift test:the accuracy of LICOR-830 is-4.22%,and the accuracy of Picarro G2301 is 0.82%.The accuracy difference between the two is five times.3)Target standard gas test:after 1h calibration of the measured concentration with concentrations of three standard gases,the precision of LICOR-830 increased by 15 times,reaching 0.026 ppm,and the accuracy was-0.11%.The precision of Picarro G2301 was slightly improved,reaching 0.0341 ppm,and the accuracy was 0.03%.The results show that the precision of LICOR-830 after calibration can meet the precision requirement that WMO recommended for CO2 measurement after calibration,which has great application potential.