目标差分吸收光谱技术测量大气NO_2平均浓度的方法研究

Research on the NO_2 Mean Concentration Measurement with Target Differential Optical Absorption Spectroscopy Technology

介绍了一种测量近地面大气NO2平均浓度的新方法——目标差分吸收光谱方法,即target DOAS(target difference absorption spectrum technology)。该方法基于被动差分吸收光谱技术,测量墙体、山体等目标的太阳反射光谱,通过差分吸收光谱算法反演得到目标与仪器之间NO2浓度沿路径的积分值SCD(slant column density),同时仪器到目标之间的距离已知,并通过选取特定的参考光谱扣除目标到大气顶层的痕量气体吸收,最终计算出仪器和目标之间的大气NO2平均浓度。利用建立的目标DOAS系统在合肥开展了观测实验,成功获取了观测地大气NO2浓度。观测结果与主动长光程差分吸收光谱仪观测数据进行对比,二者呈现较好的一致性,验证了该方法的可行性。

A new monitoring method of NO2 concentration near ground with the target difference absorption spectrum technology（Target DOAS） is introduced in the present paper.This method is based on the passive difference absorption spectrum technology.The instrument collects solar reflection spectrum of remote objectives,such as wall of building and mountain,and a specific reference spectrum is chosen to subtract the influence of trace gases from the target to atmospheric top,then integrated concentration of NO2 along the path between the target and instrument can be calculated through the differential absorption spectra inversion algorithm.Since the distance between the instrument and target is given,the mean concentration of NO2 can be derived.With developed Target DOAS instrument,NO2 concentration measurement was carried out in Hefei.And comparison was made between the target DOAS and long path difference absorption spectrometer.Good consistency was presented,proving the feasibility of this method.