中文摘要：

高精度、高准确度的大气CO2、CH4、CO浓度观测需使用以干洁大气为底气的标气.标气中水汽含量及CO2的δ13C对基于光学原理的观测系统有不可忽视的影响.本研究利用自组装的混合标气配制系统,以环境大气为底气,并通过添加高浓度气体或利用吸附剂吸附,调节目标物种浓度.CO2和CO吸附效率分别达99.7%和99.8%,标气水汽含量小于3.7×10-6（物质的量分数,下同）,可配制不同浓度范围的CO2、CH4、CO混合标气.在青海瓦里关全球大气本底站配制环境大气浓度范围的标气,CO2、CH4、CO实际配制浓度同目标浓度的偏差小于10×10-6、30×10-9、30×10-9,CO2中δ13C同实际大气接近.本方法配制的标气已应用于我国本底站大气CO2、CH4、CO高精度观测,符合世界气象组织/全球大气观测（WMO/GAW）质量要求.

英文摘要：

CO2/CH4/CO mixed standards in dry clean air are critical for high accuracy measurement.Water vapor concentration and δ13C in CO2 can significantly influence optical measurement methods.In this study,a custom-made preparation system was built to prepare the required mixed standards.Ambient air was pressurized into cylinders and target gases were adjusted by filling in high concentration gases or absorption.The absorption efficiencies of ASCARITE Ⅱ and Sofnocat423 were 99.7% and 99.8%,respectively.Water vapor in the mixing standards was less than 3.7×10-6.Seven testing standards were made at Waliguan global background station in Qinghai Province.The deviations of the prepared concentrations from the target concentrations were less than 10×10-6,30×10-9 and 30×10-9 for CO2,CH4 and CO,respectively.δ13C in CO2 was within ambient range in these testing standards.The method has already been employed to produce qualified standards for high accuracy greenhouse gases measurements at Chinese background stations,and these standards met the requirement of World Meteorological Organization/Global Atmosphere Watch（WMO/GAW）.