大气痕量气体浓度反演中的谱对准偏差研究

Wavelength Misalignment in the Retrieval of Atmospheric Trace Gases Concentration

在大气痕量气体浓度反演中,对测量光谱和计算得到的参考光谱做最小二乘拟合是常用的方法之一。但在获取光谱过程中,仪器光栅位置的不准确、温度等环境因素的变化、以及二者光谱分辨率的不同,均会导致在现场工作的监测设备所测得的光谱与计算的参考光谱之间存在谱对准偏差,即存在光谱在波长上的漂移、拉伸或压缩.这种不对准会给浓度反演带来很大的影响,介绍了在反演过程中校正谱对准偏差的算法,计算了不同光谱分辨率下由谱漂移造成的浓度反演误差.

In the retrieval of atmospheric trace-gas concentrations, it＇s a widely used method to fit the calculated reference spectra to the measured spectra with least-squares methods. However, because of inaccuracies of the grating position, thermal changes in the spectrometer, and resolution differences between the two spectra, there is a spectral misalignment between the measured spectra and the reference spectra, that is the measured spectra may be shifted or stretched/squeezed. These misalignments will affect the accuracy of the retrieval. An algorithm for the shift-and-squeeze spectral correction in the process of the retrieval is introduced and the concentration error caused by spectral shift under different resolutions is calculated.