地表发射率的机载傅里叶变换红外光谱反演方法研究

Retrieve surface emissivity from airborne Fourier transform infrared spectrum

介绍了利用机载傅里叶变换红外(FTIR)光谱仪测量地球、大气辐射的实验过程,并对由光谱仪测得的辐射与地表光谱发射率、大气透过率等参数的关系进行了深入的分析,给出了理论表达式。提出了一种基于梯度搜索的优化方法,即由机载FTIR光谱仪测得的辐亮度光谱反演得到方差最小的光谱发射率最优解。反演结果表明,在中红外波段,沙地平均光谱发射率为0.70,裸土地表平均光谱发射率为0.95。

The experimental process using airborne Fourier transform infrared（FFIR） spectrometer detecting the radiation of earth and atmosphere was described. Considering the atmospheric absorbance and emission, the relation between radiation measured by FTIR and surface emissivity is analyzed, and theoretic expression is given. A optimization method based on gradient search is presented. The surface emissivity with minimized error from the spectrum measured by airborne spectrometer is retrieved.