The Polar Atmospheric Emitted Radiance Interferometer (PAERI) has been deployed on the Antarctic Plateau in four previous field experiments. The South Pole Atmospheric Radiation and Cloud Lidar Experiment (SPARCLE) was conducted in the austral summer of 1999/2000 and for the full year of 2001. The PAERI was also deployed at Dome C (75 S, 123 E; 3280 m) for the purpose of satellite validation in the austral summers of 2002/2003 and 2003/2004. The PAERI is a Fourier-transform interferometer that measures spectral infrared radiances from 3 to 23 micrometers. It uses an extra-longwave detector that measures radiances in the semi-transparent portion of the water vapor rotational band. It can measure radiance any angle from zenith to nadir. The PAERI can take measurments at time resolutions down to seconds using a new rapid-scanning technique. Products that are currently derived from the spectral infrared radiances are the surface skin temperature, spectral infrared emissivity, clear-sky downwelling flux, spectral longwave cloud forcing, fractional cloud cover, cloud-base height, infrared cloud optical depth, effective cloud particle size, and particle phase. There is also the potential to retrieve temperature and humidity profiles in the boundary layer, the boundary-layer height, and column amounts of trace gases such as CO, CH4, and N2O. In the past we have also deployed ancillary instrumentation along with the PAERI for measuring in-situ properties of clouds using instruments on a tethered balloon system.