Determining the Total Ozone Column from Spectral Measurements of IKFS-2 in 2015–2022

The results of determining the ozone total column (OTC) from the spectra of the outgoing thermal infrared radiation measured by the IKFS-2 instrument from the Meteor-M No. 2 spacecraft during 8 years of measurements are presented. The previously developed technique for the interpretation of spectral measurements made in 2015–2020 with a swath width (SW) of 1000 km is applied to the measurements in 2021–2022 with a SW of 1500 km. It is shown that the increase in the differences between the IKFS-2 data and the results of independent measurements is caused not by the expansion of the OTC variability statistics, but by the increase in the range of scanning angle variation. After a finalization of the technique for the measurements with a 1500-km SW, a comparison with independent data showed that the standard deviations of differences with the results of ground and satellite measurements for all 8 years do not exceed 3% and did not increase compared to the first 6 years of measurements. To analyze the results in the polar regions, the OTC values obtained from the IKFS-2 spectra are compared with the ozonesonde data, which are performed continuously throughout the year, including the polar night. A good qualitative agreement of the IKFS-2 data and ozone sounding data, including winter–spring periods of extreme OTC decrease at high latitudes of both hemispheres, is shown. The standard deviations of the differences between the IKFS-2 data and the OTC values from ozone sounding data were from 5.3 to 11% (17–33 DU) for different stations, or on average for all stations 7.9%, which is consistent with the uncertainty of the estimates of the integrated ozone content in the vertical column from ozonesonde data.