Abstract. Profiles of CFC-11 (CCl3F), CFC-12 (CCl2F2) and HCFC-22 (CHF2Cl) have been obtained from Fourier transform infrared (FTIR) solar absorption measurements above the Saint-Denis (St Denis) and Maïdo sites at Reunion Island (21º S, 55º E) with low vertical resolution. FTIR profile retrievals are performed by the SFIT4 program and the detail retrieval strategies along with the systematic/random uncertainties of CFC-11, CFC-12, and HCFC-22 are discussed in this study. The FTIR data of all three species are sensitive to the whole troposphere and the lowermost stratosphere, with the peak sensitivity between 5 and 10 km. The trends derived from the combined St Denis and Maïdo FTIR time-series are −0.86 ± 0.12 % and 2.75 ± 0.12 % for CFC-11 and HCFC-22, respectively, for the period 2004 to 2016 , and −0.76 ± 0.05 % for CFC-12 for 2009 to 2016. These measurements are consistent with the trends observed by the National Oceanic and Atmospheric Administration (NOAA) Global Monitoring Division’s (GMD) Halocarbons & other Atmospheric Trace Species Group (HATS) measurements at Samoa (14.2° S, 170.5° W) for CFC-11 (−0.87 ± 0.04 %), but slightly weaker for HCFC-22 (3.46 ± 0.05 %) and stronger for CFC-12 (-0.60 ± 0.02 %). The ground-based FTIR data have also been compared with the collocated Michelson Interferometer for Passive Atmospheric Sounding (MIPAS/ENVISAT) data, and found to be in good agreement: the observed mean relative biases and standard deviations of the differences between the smoothed MIPAS and FTIR partial columns (6−30 km) are (−4.3 % and 4.4 %), (−2.9 % and 4.6 %) and (−0.7 % and 6.0 %) for CFC-11, CFC-12, and HCFC-22, respectively, which are within the combined error budgets from both measurements.;
