大气二氧化碳垂直廓线的球载探测研究

The atmospheric carbon dioxide (CO2) is a greenhouse gas which plays a dominant role in climate changes and also on some other fields. High-precision vertical profiles of atmospheric CO2 have great significance to validate the data from satellite and aerial remote sensing, radiative transfer and so on. And there are a lot of advantages about CO2 sonde such as cost-effective, high-precision and high-resolution. NDIR technology has been successfully applied in the CO2 detection domain because of high detection precision due to using standard gas to calibrate the detection system. However, as to the CO2 sonde system, the parameters of temperature and pressure of the ambient air from ground level to 20 kilometer are changed which bring about the CO2 molecule absorption cross section to be changed. So the calibration coefficients of the detection are not precise enough which cause the accuracy to be lower. What’s more, varieties of meteorological parameters can also affect the property of the source，the detector and the filter transmittance of the CO2 sonde. To overcome the above problems, we propose that according to the certain order to acquire standard CO2 gas and ambient gas in the whole process of sonde ascending, through the quasi-real-time calibration method to get the high-precision spatial distribution of the atmospheric CO2 from ground level to 20 kilometer. It can provide strong support for the study of the environmental climate changes, the exploration of the pattern of pollutant spreading and the guarantee of national low carbon economy growth.

大气CO2是一种温室气体，在气候变化等领域扮演着重要角色。高精度大气CO2垂直廓线对于卫星遥感数据的验证、辐射传输计算等方面都有着指导作用。球载大气CO2垂直廓线的探测手段具有高性价比、高精度和高分辨率等优点。非分散红外技术通过标准气体标定来确定系统参数使其具有较高的探测精度而被广泛应用于大气CO2的检测研究中。然而对于探空0~20km范围内，温度、压强的变化导致CO2分子谱线吸收截面发生变化，使得地面上标定参数不准确；同时外界环境的变化会对红外光源、探测器及滤光片透过率参数造成一定的影响，使得系统探测精度变低。为克服上述问题，本课题提出在球载探测系统上升过程中按照确定的次序采集标准CO2气体与环境气体的方法对系统进行准实时标定，进而精确探测0~20km大气CO2的空间分布，为预测环境气候变化、探索污染物扩散规律及保障国家低碳经济发展等方面的研究提供有力支持。

大气二氧化碳是一种重要的温室气体，同时也是气候变化、环境外交的焦点问题。高时空分辨率的大气二氧化碳垂直廓线对于碳排放策略的制定、红外辐射强迫的影响、碳源汇的理解以及激光雷达/卫星遥感数据的验证、标定等方面都有着指导作用。然而目前这种数据还比较匮乏。本项目开展了大气二氧化碳垂直廓线的球载探测技术研究，模拟计算了大气二氧化碳吸收截面随高度的变化情况；研制了一套小型化、低功耗的球载探测系统；发展了一套大气二氧化碳探空数据提取、去噪及浓度反演综合数据处理软件。实现了大气二氧化碳、温度、湿度、压强的垂直廓线同时探测。初步的探测结果表明：大气二氧化碳具有明显的时空变化特征。具体在时间上，中午时段二氧化碳浓度最低，午后慢慢增加，夜晚浓度最高。由于扩散等原因，在空间上也具有相应的昼夜变化特征，但是随着高度的上升，这种趋势慢慢变弱。项目的开展丰富了大气二氧化碳垂直廓线的探测手段，弥补了大气二氧化碳探测激光雷达盲区、几何因子区的影响，为环境气候变化预测、研究碳扩散规律及保障国家低碳经济发展等方面提供设备与数据支持。