RECENT RESULTS FROM TWO NEW AIRCRAFT-BASED FOURIER-TRANSFORM INTERFEROMETERS : The Scanning High-resolution Interferometer Sounder and the NPOESS Atmospheric Sounder Testbed Interferometer

The Scanning High-resolution Interferometer Sounder (S-HIS) and the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Atmospheric Sounder Testbed Interferometer (NAST-I) are new aircraft-based instruments that measure accurate infrared radiances at both high spectral and spatial resolution. The designs of both instruments are based upon the High-resolution Interferometer Sounder (HIS) and the ground-based Atmospheric Emitted Radiance Interferometer (AERI). However, both the new instruments are capable of cross-track scanning, which is important for the retrieval of atmospheric profiles of temperature, water vapor and other trace gases in the presence of clouds. The data from these instruments will be used to simulate future operational satellite sounders to evaluate their instrument specifications, measurement characteristics, and data-processing techniques. This paper provides a brief description of each instrument, followed by an explanation of a general approach to correcting for detector nonlinearities. Preliminary data from the S-HIS, taken during the third Convection and Moisture Experiment (CAMEX3), are compared with radiative transfer model calculations.