The Imaging Infrared Radiometer (IIR) was one of three instruments aboard the joint NASA/CNES (Centre National d'Etudes Spatiales) Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite. IIR and CALIPSO's Cloud and Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument worked together to sample the same cloud, with IIR providing data about layer-average cloud properties and CALIOP sampling the same 1 km IIR pixel to acquire vertical profiles of the cloud layers.