基于压差的二氧化碳垂直采样分析技术

本研究开发了一套基于直接采样技术的二氧化碳（CO₂）垂直廓线采样分析系统，分析近地面至25km高空CO₂浓度的垂直分布.系统通过压差实现垂直方向连续采样，利用CRDS高精度分析技术对不同高度样品进行定量分析，计算得到采样区域CO₂浓度廓线.于2018年6月13~14日，在内蒙古锡林浩特国家气候观象台利用平流层探空气球平台进行了观测实验.实验室测试显示，CO₂分析准确度优于0.06×10^-6，精度优于0.08×10^-6.外场实验获得区域近地面至25km高空CO₂浓度的高分辨率垂直廓线，显示CO₂在不同高度的分层结构.考虑不同高度样品扩散作用，系统垂直分辨率在10km高度以下优于580m，在10~20km高度优于3.3km.研究表明：分析系统可搭载在合适探空平台上进行CO₂垂直观测，获取浓度廓线，可为传输模式提供数据，并为碳卫星遥感数据提供实测数据校验.

A balloon-borne sampler system based on the pressure gradient for vertical profile measurements of CO2

A balloon-borne sampling system for vertical profile of atmospheric CO₂ from the surface to 25 km was developed and field-tested. The sampler is deployed on a stratospheric balloon and relies on passively collecting air using the atmospheric pressure gradient during descent. The atmospheric sample through continuous sampling is measured by a cavity ring-down spectrometer (CRDS) for CO₂ upon recovery. Field campaigns were conducted for the first time on June 13^th and 14^th, 2018 at Xilinhaote Observatory. Measurements of CO₂ mole fractions in laboratory tests indicated a repeatability of 0.08×10^-6 and bias to better than 0.06×10^-6 (1σ) for CO₂ under various conditions. The vertical resolution with our configuration was determined to be 580m up to 10km and better than 2.0km up to 20km respectively according to the molecular diffusion of the sample. The system provides an in situ method of greenhouse gas measurements for validation of satellite data and estimation of regional flux.