The scientific objectives of FIRE Arctic Cloud Experiment, which took place between May 13 and June 7, 1998, include studying the impact of Arctic clouds on radiation exchange between surface, atmosphere, and space, and the influence of surface characteristics of sea ice, leads, and ice melt ponds on these clouds. High spectral resoulution (approximately 1 cm**-1) infrared observations (approximately 600-2700 cm**-1) obtained at two ground sites and from the NASA ER-2 high-altitude aircraft contribute to achieving these objectives. This paper focuses on the High-spectral resolution Infrared Sounder (HIS) measurements made from the ER-2. The paper will 1) Compare the infrared radiative characteristics of the Arctic with previous FIRE observations, 2) Retrieve Arctic cloud radiative properties 3) Assess how multi-level clouds affect interpretation of satellite measurements of clouds, and 4) Assess how accurately high-spectral resolution IR observations satellites detect the presence of Arctic clouds.