Figure S1. Example of transmittance spectra recorded by TIRVIM in solar occultation at orbit 2520 at different altitude in comparison with direct modeling at target altitude of 20 km for three main gases CO₂, H₂O and CO. Shaded areas show the range of CO 1-0 and 2-0 bands at 4.7 and 2.3 µm used for retrieval in this work.

TIRVIM stopped working in December 2019 (Ls=115° MY35) having recorded ~1000 solar occultations. We found about 550 co-located observations where the retrieval was done with NIR temperature profiles (Fig. S2). Overall, the profiles are well consistent in different locations and seasons (Fig. S3). However, the large FOV of TIRVIM (~2° equal to ~60 km at the limb) makes the contribution of scattered light around the Sun close to the solar signal in the low atmosphere where the aerosol opacity reduces the signal. To make the valid retrieval of gaseous absorption in dusty condition the full radiative transfer with multiple scattering is needed, a difficult problem, given the poorly constrained FOV. We therefore limited the TIRVIM retrievals to transmittance of 0.6 (the aerosol slant optical depth of ~0.5).