Algorithm development for atmospheric gas remote sensing by measuring the high resolution spectrum and polarization

1.提出了几种利用偏振效应校正云和气溶胶散射的方法。假设用光谱分辨率为0.2cm ↑ [2]的傅里叶变换光谱仪在1.6 μ波段观测地球反射的太阳辐射，进行了气体反演的模拟<-1>。实验结果表明，与不使用偏振相比，使用偏振后CO_2柱量的反演误差减小了0.5%左右。2.由于像移补偿机制的不完善，导致星载FTS的瞬时视场（IFOV）位置产生波动。利用卫星观测图像资料表明，IFOV的这种波动会引起CO_2柱量反演的较大误差。为了校正IFOV波动的影响，提出了一种利用FTS带通滤波器外的低频频谱进行修正的方法。3.考虑了地球绕日公转对谱线多普勒频移的影响，研究了地球自转和卫星运动的关系。4.研制了一个利用地基高光谱遥感技术估算地外太阳光谱的程序。5.利用地基高光谱遥感技术对CO_2含量进行了长期监测。FTS决议已经启动。初步精度检验表明，与塔台观测和航空观测的结果吻合较好，CO_2相对值精度优于0.2%。

1.A few methods to use the polarization have been developed for correcting the scattering of light by cloud and aerosols in remote sensing atmospheric gases from space. Simulations of retrieval of gases have been performed assuming the observation of Earth-reflected solar radiation is made in the 1.6 μ band with a FTS (Fourier Transform Spectrometer) having a spectral resolution 0.2cm^<-1>. It has been shown that the retrieval error of CO_2 column amount is reduced by about 0.5 % when the polarization was used compared with non-use of polarization.2.Incomplete performance of IMC (Image Motion Compensation) mechanism generates a fluctuation of the position of IFOV (Instantaneous Field of View) of satellite borne FTS. It has been shown, by using satellite-observed image data, that this fluctuation of IFOV generates large retrieval error of CO_2 column amount. To correct the effect of IFOV fluctuation, a method has been developed by using the low frequency spectrum out side the band pass filter of FTS. It has been found that the error is greatly reduced by applying this method.3.The effect of Doppler shift of spectral lines due to the Earth revolution around the sun, spin motion of the Earth and satellite motion has been investigated.4.A program has been developed to estimate the extra-terrestrial solar spectrum from ground-based high spectral-resolution FTS.5.A long term monitor of CO_2 amount from ground-based high spectral-resolution FTS has been initiated. The preliminary test of accuracy showed a good coincidence with the tower observation and air borne observation, showing the accuracy of relative value of CO_2 better than 0.2 %.