Based on analyzing the relationship between the atmospheric downward radiance and surface emis- sivity, this paper proposes a correlation criterion to optimize surface temperature during the process of temperature and emissivity separation from thermal infrared hyperspectral data, and puts forward the correlation-based temperature and emissivity separation algorithm (CBTES). The algorithm uses the correlation between the atmospheric downward radiance and surface emissivity to optimize surface temperature, and obtains surface emissivity with this temperature. The accuracy of CBTES was evalu- ated by the simulated thermal infrared hyperspectral data. The simulated results show that the CBTES can achieve high accuracy of temperature and emissivity inversion. CBTES has been compared with the iterative spectrally smooth temperature/emissivity separation (ISSTES), and the comparison results show that they have relative accuracy. Besides, CBTES is insensitive to the instrumental random noise and the change of atmospheric downward radiance during the measurements. As regards the noniso- thermal pixel, its radiometric temperature changes slowly with the wavenumber when its emissivity is defined as r-emissivity. The CBTES can be used to derive the equivalent temperature of nonisothermal pixel in a narrow spectral region when we assumed that the radiometric temperature is invariable in the narrow spectral region. The derived equivalent temperatures in multi-spectral regions in 714―1250 cm?1 can characterize the change trend of nonisothermal pixel's radiometric temperature.
在分析地面测量大气下行辐射和地表发射率之间关系的基础上，给出了针对热红外高光谱数据温度与发射率分离过程中地表温度优化的相关性判据，提出了基于相关性的温度与发射率分离算法（the Correlation Based Temperature Emissivity Separation Algorithm，CBTES）。该算法利用大气下行辐射和地表发射率之间的相关性优化地表温度，进而获得地表发射率。基于模拟的热红外高光谱数据，对CBTES算法的精度进行分析，结果表明CBTES算法具有较高的温度与发射率反演精度；并与光谱迭代平滑温度发射率分离算法（ISSTES）进行比较，发现CBTES算法具有和ISSTES算法相当的精度。此外，CBTES算法具有一定的抗噪性，对测量过程中大气下行辐射的变化不敏感；对于非同温像元，当其发射率定义为r-emissivity时，其辐射温度是对波数缓慢变化的，假设在比较窄的光谱区间内辐射温度近似不变，可以用CBTES算法反演非同温像元在窄光谱区间内的等效温度，在714-1250cm^-1。光谱区间内多个窄光谱区间反演的等效温度可以较好的刻画非同温像元辐射温度的变化趋势。
