基于LICOR-830与Picarro G2301的温室气体分析仪精度对比研究

COMPARATIVE STUDY ON THE PRECISION OF GREENHOUSE GAS ANALYZERS BASED ON LICOR-830 AND PICARRO G2301

在应对气候变化和实现“双碳”战略过程中,需要对温室气体进行高精度的观测,而目前在实验室关于量化不同观测系统精度差异的研究相对较少。本研究选择基于非色散红外吸收法的LICOR-830型CO_(2)气体分析仪与基于光腔衰荡光谱法的Picarro G2301型CO_(2)/CH4/H2O气体分析仪,对3种CO_(2)可溯源标气进行观测,开展重复性测试、漂移测试和目标标气测试,并对观测浓度进行精度对比分析。测试结果为1)重复性测试:LICOR-830的精度约为0.4 ppm,Picarro G2301的精度约为0.04 ppm,两者精度相差一个数量级;2)漂移测试:LICOR-830准确度为-4.22%,Picarro G2301准确度为0.82%,两者准确度相差5倍;3)目标标气测试:用3种浓度的标气对实测浓度进行1 h的校正后,LICOR-830精度提升15倍,达到0.026 ppm,准确度为-0.11%,Picarro G2301的精度略有提升,达到0.0341 ppm,准确度为0.03%。结果显示,LICOR-830的精度水平在校正后可满足WMO对CO_(2)观测的精度要求,具有较大的应用潜力。

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 CO_(2) gas analyzer based on non-dispersive infrared absorption method and the Picarro G2301 CO_(2)/CH4/H2O gas analyzer based on cavity ring-down spectroscopy method were selected to observe the three traceable standard CO_(2) 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 CO_(2) measurement after calibration,which has great application potential.