直射太阳光红外吸收光谱技术遥测大气中二氧化碳柱浓度

Study on remote sensing of carbon dioxide column concentration in the atmosphere by direct-sun infrared absorption spectroscopy

大气中二氧化碳浓度持续增高导致环境和气候变化等问题成为人们关注的焦点.为了实时遥测二氧化碳气体柱浓度,研究了一种地基低分辨遥测系统和实时光谱数据反演分析方法.利用该系统在合肥地区进行了连续观测,从太阳吸收光谱中实时获取了整层大气透过率.采用逐线积分非线性最小二乘光谱反演算法,从整层大气透过率中反演了二氧化碳柱浓度和氧气柱浓度,并以氧气柱浓度为内标函数获得了二氧化碳干空气柱体积混合比,精密度优于3%.将2012年9月25日12时到15时本系统测量的二氧化碳干空气柱体积混合比均值与此时段过境本站点区域的日本温室气体卫星观测结果进行了比较,两者偏差小于1%.可见,该系统和方法具有很高的精密度和准确度,是一种有效的温室气体观测手段.

The concentration of carbon dioxide in the atmosphere has been increasing continuously. This is a big concern with respect to the environment and climate changes and so on. A kind of ground-based low-resolution remote sensing system and a real-time spectral inversion method are presented for the real-time remote sensing column concentration of carbon dioxide. Based on continuous observation of this system in Hefei, the total atmospheric transmittance is real-timely obtained from the solar absorption spectrum. The column concentrations of carbon dioxide and oxygen are inversed from total atmospheric transmittance by line-by-line nonlinear least squares spectral inversion algorithm. The column concentration of oxygen is used as internal standard function to obtain the column average volume mixing ratio of carbon dioxide in total dry air column, and the precision is better than 3%.The average volume mixing ratio of carbon dioxide in dry-air column, from 12：00 to 15 ： 00 on September 25, 2012, is compared with observation results by Japanese greenhouse-gases satellite over the site in this period, showing that the relative deviation is less than 1%. Obviously, it is an effective way to measure greenhouse gases concentration with high precision and accuracy.