根据EOS/Terra多传感器的特点,提出了一个适合于ASTER数据的劈窗算法,该算法包括两个必要的参数大气透过率和比辐射率。大气透过率是通过利用MODIS的3个近红外波段反演大气水汽含量并根据大气水汽含量与热红外波段的统计关系计算得到。由于MODIS和ASTER是在同一颗星上,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。对于比辐射率则是通过分类和JPL提高的光谱库获得。最后用大气模拟校正法对算法进行了验证,在比辐射率已知的情况下,当使用大气模型模拟得到的大气透过率时,对Planck函数优化简化后的平均精度为0.56℃;当大气透过率是从大气水汽含量计算得到时,优化平均精度为0.58℃,表明该算法可行。
According to the multiple-instrument characteristics of the Terra (EOS) satellite, this paper presents a split-window algorithm to retrieve the land surface temperature from ASTER data, which involves two essential parameters (transmittance and emissivity). The Planck function was simplified by linearity simulation. The atmosphere transmittance was obtained from MODIS NIR bands. Validation for split-window algorithm with standard atmospheric simulation indicates that the average accuracy of this algorithm is about 0.56℃ in LST retrieval for the case without error in both transmittance and emissivity estimations and the accuracy of this algorithm is about 0.58℃ when the transmittance is computed from the simulation water content by linear fitting.