我国典型区域甲烷垂直浓度廓线观测技术研究

Temporal and spatial variations in CH4 vertical profiles are significant for picturing the distribution of emissions and sinks. While there are sparse techniques for measuring vertical profiles of CH4 in China. Most researches focus on surface measurements and satellites or spectrometer-based remote sensing method providing column integrated CH4. This study plans to set up a sampling-analysis system which conducts on-site CH4 sampling in high altitude continuously. Takeoff of the balloon, quick recovery and high-precious analysis of sampler and vertical profiles retrieval techniques are explored. Procedures and parameters are optimized through laboratory experiments and practical measurements. Finally, a systematic procedure involved sampling, analysis, calibration and profile retrieval for CH4 will be built up. High spatial resolution will be obtained to 100-2000m in the altitude of 0 to 30 km. According to this procedure, vertical profiles of CH4 and its seasonal cycle in typical region in China will be obtained initially. This system is an innovative technique for validating the retrieval method of satellite and ground-based spectrometer.

CH4垂直尺度浓度廓线的时空变化，对于准确反演其源汇变化特征至关重要。而目前我国CH4研究主要集中在地面观测及利用卫星和地基遥感观测反演柱总量结果，缺乏平流层大气甲烷原位探测技术，且目前中国CH4垂直分布观测尚未见报道。本项目拟研制适用于大气CH4廓线原位探测的方法和系统，集成与优化高空气球放飞与及时回收技术、采样气体分析技术和廓线数据分析方法，建立适合我国典型区域的垂直采样-分析-标校-廓线反算系统，实现0-30km大气CH4的高分辨率（100-2000m）垂直观测，结果溯源至WMO尺度。在此基础上，初步获得中国典型区域CH4垂直浓度廓线的季节变化。本研究可以为基于卫星遥感和地基光谱的反演算法以及大气化学传输模式提供校验方法。

本项目针对对流层及下平流层甲烷等温室气体浓度分布，基于气象探空平台，研制出一套大气温室气体原位探测的技术方法，建立Aircore垂直采样-分析-标校-廓线反算系统。技术可实现0-30km大气CH4的高分辨率（100-3000m）垂直观测，结果溯源至WMO尺度，精度满足WMO/大气观测网对于本底观测的可比性要求：CO2优于0.1ppm，甲烷优于0.2ppb。通过外场试验，优化了高空气球放飞与及时回收技术、采样气体分析技术和廓线数据分析方法，解决了进样阀开关自动控制、高精度样品分析、浓度和高度精准对应等关键难点，形成具有应用前景的硬件系统、数据处理软件、和技术操作流程。应用此方法共开展了5次外场试验，获得甲烷近地面至平流层廓线数据共12套，CO2等其他温室气体廓线数据共28套。数据资料可以为卫星遥感和地基光谱的反演算法以及大气化学传输模式提供校验。.依托项目成果，发表论文2篇；项目负责人作为第一作者或通讯作者文章3篇，其中包括SCI论文2篇，EI收录论文1篇；发明专利3项目，实用新型专利6项；软著1项。