An Airborne Interferometer for Atmospheric Emission and Solar Absorption

The interferometer for emission and solar absorption INTESA is an infrared spectrometer designed to study radiative transfer in the troposphere and lower stratosphere from a NASA ER-2 aircraft. The Fourier-transform spectrometer FTS operates from 0.7 to 50 μm with a resolution of 0.7 cm⁻¹ . The FTS observes atmospheric thermal emission from multiple angles above and below the aircraft. A heliostat permits measurement of solar absorption spectra. INTESA’s calibration system includes three blackbodies to permit in-flight assessment of radiometric error. Results suggest that the in-flight radiometric accuracy is ~0.5 K in the mid-infrared.