Emission Fourier Transform Spectroscopy for the Remote Sensing of the Atmosphere

Fourier transform spectrometers, thanks to their intrinsic advantages of high throughput, high spectral resolution and multiplex acquisition of spectral channels, offer a powerful tool for the characterization of the Earth's atmosphere. The use of photon noise limited detectors in FTS instruments operating in the middle/far infrared spectral region permits high sensitivity emission spectroscopy measurements, without the limitations arising from the use of an external radiation source. The wide operating spectral range of FTS instruments makes possible simultaneous detection of different atmospheric chemical species that show rotational and vibrational spectral bands in the middle/far infrared region. Spatially resolved measurements of the concentration of the interesting species are of fundamental interest in the study of local phenomena in atmospheric chemistry and physics, and can be obtained through the use of various observation and data inversion techniques. Among these, the best results in terms of vertical resolution are achieved through the limb sounding 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 using Far InfraRed Emission - Airborne) during the Antarctic campaign APE-GAIA (Airborne Polar Experiment - Geophysica Aircraft In Antarctica, Ushuaia, Argentina, September-October, 1999) are presented.