The National Airborne Sounder Testbed-Interferometer (NAST-I): Existing technology for new science and applications

The National Airborne Sounder Testbed-Interferometer (NAST‑I) is an existing ultraspectral infrared sounder flown on high-altitude aircraft that provides high spectral and spatial resolution measurements which continue to advance understanding of science critical for weather, climate, chemistry, and radiation applications. NAST‑I provides high-spatial linear resolution equal to 13% of the aircraft altitude at nadir (i.e., 2.6 km IFOV on the ground from an aircraft altitude of 20 km), and high-spectral resolution (0.25 cm^-1) measurements within the spectral region of 645–2700 cm^‑1. The NAST‑I suborbital system serves as a spaceborne instrument simulator and pathfinder for future satellite capabilities and airborne science experiments. Presented herein are some groundbreaking capabilities of NAST-I measurements and corresponding geophysical retrievals and their potential benefits toward improved atmospheric state and composition characterizations needed for air quality, wildfire, and other science applications. As detailed, such capabilities could be of particular importance toward enhancing characterization and understanding of the Planetary Boundary Layer (PBL).