Carbon tetrafluoride (CF4 or FC-14) is produced mainly as a byproduct of the manufacture of aluminum. CF4 does not harm the stratospheric ozone layer, but it is a powerful greenhouse gas due to its absorption characteristics in the infrared. It is an inert tracer and has a very long lifetime in the stratosphere (probably many thousands of years). Thus it is expected to be uniformly mixed both geographically and vertically around the globe. Measurements of the carbon tetrafluoride reveal that it is essentially independent of altitude up to at least 50 km (e.g. ATMOS observations). The MIPAS experiment, onboard Envisat satellite, launched on 1st March 2002, is a high resolution Fourier Transform Spectrometer observing infrared limb emission spectra. From these measurements, profiles of atmospheric pressure, temperature and several species can be retrieved. MIPAS spectra contain also information on carbon tetrafluoride. In the present study we use Envisat-MIPAS to retrieve carbon tetrafluoride and we quantify its concentration as a function of altitude in the altitude range 6-68 km. Here we present new measurements of CF4 mixing ratios at high altitude, where few measurements have been made in the past.
