The University of Wisconsin Space Science and Engineering Center Absolute Radiance Interferometer (ARI): Predicted and Demonstrated Radiometric Performance

Spectrally resolved thermal radiances measured from orbit with extremely high absolute accuracy (< 0.1 K, k = 3, brightness temperature at scene temperature) constitute a critical observation for future climate benchmark missions. The challenge in the infrared (IR) sensor development for a climate benchmark measurement mission is to achieve this ultra-high accuracy with a design that can be flight qualified, has long design life, and is reasonably small, simple, and affordable. In this area, our design approach for the Absolute Radiance Interferometer (ARI) made use of components with strong spaceflight heritage (direct analogs with high TRL) combined into a functional package for detailed performance testing. The required simplicity is achievable due to the large differences in the sampling and noise requirements for the benchmark climate measurement from those of the typical remote sensing infrared sounders for weather research or operations. Recent laboratory testing of the Absolute Radiance Interferometer (ARI) has demonstrated the capability to meet the 0.1 K (k = 3) uncertainty requirement on-orbit. A summary of the radiometric performance of the ARI at the University of Wisconsin Space Science and Engineering Center (UW-SSEC) will be presented.