采用多通道式热红外辐射计CE312开展敦煌辐射校正场红外特性的研究,通过测量场地目标和红外标准板获取地表辐射亮度和大气下行辐射亮度,再采用多通道温度与发射率分离算法得到场地通道发射率和场地温度,最后利用最优偏移量法得到场地发射率光谱;将其与利用102F傅里叶变换红外光谱仪对相同目标区域进行测量,并采用光谱迭代平滑温度与发射率分离算法分离出的结果进行比较,两种算法获得的通道发射率最大偏差在0.011以内,场地温度偏差在0.104 K以内,说明采用多通道式热红外辐射计可以实现场地温度和发射率的分离,获得高精度的热红外场地参数。本试验为基于敦煌辐射校正场开展卫星遥感器热红外波段场地自动化观测绝对辐射定标提供了参考。

A multichannel thermal infrared radiometer, called CE312, was used to study the infrared characteristics of the Dunhuang radiometric correction field. Site surface radiance and the downwelling atmospheric radiance were obtained by measuring the target site and the infrared standard plate. The multichannel temperature and emissivity separation algorithm was used to calculate the site channel emissivity and temperature. Finally, the optimal offset method was employed to obtain the site emissivity spectrum. The same target area was measured using a 102F Fourier transform infrared spectrometer. The results separated by the iterative spectral smooth temperature and emissivity algorithm were then compared with those separated by the multichannel temperature and emissivity separation algorithm. The comparison results show that the maximum deviation of the channel emissivity obtained by the two methods is within 0.011, and the site temperature deviation is within 0.104 K, indicating that the usage of the multichannel thermal infrared radiometer can separate the site temperature and emissivity in addition to obtaining high-precision thermal infrared site parameters. This test provides a reference for the automated observational absolute radiometric calibration of the satellite remote sensing thermal infrared band based on the Dunhuang radiometric correction field.