Interferometer for the detection of absolute, spectrally resolved radiance

The Interferometer for Emission and Solar Absorption (INTESA) is an infrared spectrometer designed for studies of radiative transfer and remote sensing in the upper troposphere and lower stratosphere. The Fourier transform spectrometer covers a spectral range from 200 to 3500 cm^-1, with an unapodized resolution of 0.6 cm^-1. It observes atmospheric thermal emission in the zenith, nadir and selectable elevation angles above and below the aircraft with an overall radiometric accuracy of 0.1 K. Expressed as radiance, this accuracy corresponds to an error of less than one part in 10³ in the mid-infrared. This airborne instrument is designed to analyze the radiative properties of cirrus and their relation to the microphysical properties of the particles that comprise the clouds; determine heating rates in the critical mid/upper troposphere, tropopause, and lower stratosphere regions; Establish the spectral signature of cirrus to provide the required “fingerprint” for satellite observations and to provide direct observations of the relationship between altitude dependent concentrations of molecular concentrations and cirrus cloud composition and the upwelling/downwelling, spectrally resolved radiance.