Emission Fourier Transform Spectroscopy for the Remote Sensing of the Atmosphere

Fourier transform spectrometers, thanks to their intrinsic advantages ofhigh throughput, high spectral resolution and multiplex acquisition ofspectral channels, offer a powerful tool for the characterization of theEarth's atmosphere. The use of photon noise limited detectors in FTSinstruments operating in the middle/far infrared spectral region permitshigh sensitivity emission spectroscopy measurements, without thelimitations arising from the use of an external radiation source. The wideoperating spectral range of FTS instruments makes possible simultaneousdetection of different atmospheric chemical species that show rotationaland vibrational spectral bands in the middle/far infrared region.Spatially resolved measurements of the concentration of the interestingspecies are of fundamental interest in the study of local phenomena inatmospheric chemistry and physics, and can be obtained through the use ofvarious observation and data inversion techniques. Among these, the bestresults in terms of vertical resolution are achieved through the limbsounding observation technique from airborne platform.As an example of possibilities offered by the above considered technique,results obtained from the SAFIRE/A (Spectroscopy of the Atmosphere usingFar InfraRed Emission - Airborne) during the Antarctic campaign APE-GAIA(Airborne Polar Experiment - Geophysica Aircraft In Antarctica, Ushuaia,Argentina, September-October, 1999) are presented.