I. Introduction
Snow cover has a strong impact on surface energy balance. Snow spectral emissivity is a key parameter for the accurate determination of snow surface temperature, which is an indicator of cryospheric climate change and often used as an initial value in climate models [1], [2]. This parameter also determines the long-wave upwelling radiation of snow surfaces. Moreover, remote sensing of atmospheric temperature-humidity profiles and trace gases over snow surfaces, using a nadir-view sensor, requires a priori snow emissivity for accurate retrieval [3]–[5].