本文利用对地观测卫星多传感器的特点,提出了针对ASTER数据同时反演地表温度和比辐射率的多通道算法。即利用ASTER数据的第11,12,13,14热红外波段建立热辐射传输方程,并通过对于地表比辐射率分析可知,ASTER4个热红外波段的比辐射率可以用近似线性方程表示,得到了6个方程6个未知数,从而形成了针对ASTER数据的同时反演地表温度和比辐射率的多通道算法。对于关键参数大气透过率,则是通过同一颗星的MODIS传感器的3个近红外波段反演大气水汽含量,然后用MODTRAN模拟大气水汽含量与ASTER热红外波段的统计关系,并进而根据这二关系来计算ASTER热红外波段的大气透过率。由于MODIS和ASTER是在同一颗星上。因此这种大气透过率估计方法保证了地表温度反演过程中所需大气参数的同步获取。
According to the multiple-instrument characteristics of the Terra (EOS) satellite. A multiplechannel algorithm was proposed to retrieve land surface temperature and emissivity from ASTER/MODIS data at the same time. That is, at first, four thermal bands( 11, 12, 13, 14) of ASTER were utilized to build radiance transfer equation. After analyzing the characteristics of the emissivity in ASTER TIR, the parameter emissivity is described approximately as two linear equations. Thus, the multiple-band algorithm retrieving I.ST and emissivity from ASTER/MODIS data comes into being after uniting four radiation transfer equation and the linear equation of emissivity. The key parameter transmittance is obtained from retrieved water content of atmosphere through NIR bands of MODIS. Because ASTER and MODIS data are on the same satellite, the transmittance was timely obtained.