基于差分吸收光谱技术的大气痕量气体二维观测方法

Two-dimensional observation of atmospheric trace gases based on the differential optical absorption spectroscopy technique

基于差分吸收光谱技术,对大气痕量气体二维观测方法进行研究.对常规多轴差分吸收光谱系统进行改进,使望远镜可指向不同方位角,获取测量点各方位角上的痕量气体信息,从而更直观地了解测量点四周污染气体分布及其演变情况.主要对NO2浓度分布进行了研究,同时获取了不同方位角上的O4斜柱浓度;采用辐射传输模型模拟计算O4斜柱浓度并与实测数据对比,结果表明二者具有高度相关性,验证了大气中O4分布的稳定性;基于实测O4数据提取光路信息,结合辐射传输模型对NO2和O4因廓线不同造成的散射路径差异进行修正,将NO2斜柱浓度进一步转化为体积混合比,获得了不同方位角上NO2浓度分布图.将计算结果与长光程差分吸收光谱技术数据进行对比,结果表明二者具有较好的一致性.

A two-dimensional observation method of atmospheric trace gases based on differential optical absorption specw troscopy technique is reported in this paper. The conventional multi-axis differential absorption spectrum system is improved to make the telescope point to different directions. Thereby, the trace gas information of different azimuthal angles and consequently the distribution and variation of pollution gases around the measurement point can be obtained simultaneously. Using this method, NO2 concentration and distribution as well as O4 slant column densities are ob- tained. High degree of similarity is shown between O4 slant column density simulated by radiation transfer model and the measured data. Based on the measured O4 data, light path information can also be extracted. By combining with radiation transfer model, the light path differences caused by different profile modifications are corrected. The corrected NO2 slant column density is further converted into the volume mixing ratio. By comparing the calculated NO2 mixing ratio with the long-path-differential optical absorption spectroscopy data, the results show good consistency with each other.