Separating temperature and emissivity in thermal infrared multispectral scanner data: implications for recovering land surface temperatures

The accuracy of three techniques for recovering surface kinetic temperature from multispectral thermal infrared data acquired over land is evaluated. The three techniques are the reference channel method, the emissivity normalization method, and the alpha emissivity method. The methods used to recover the temperature of artificial radiance derived from a wide variety of materials. The results indicate that the emissivity normalization and alpha emissivity techniques are the most accurate, and recover the temperature of the majority of the artificial radiance spectra to within 1.5 K; the reference channel method produces less accurate results. The primary advantage of the alpha emissivity method over the emissivity normalization method is that it works well in terrains of widely varying emissivities, e.g.,those dominated by vegetation and igneous rocks. By contrast, the emissivity normalization method works well only if the emissivity used for normalization is close to the maximum emissivity of the spectra in the scene