CO2 total columns in Mexico-City

Seven solar-viewing Fourier transform infrared (FTIR) spectrometers were deployed during an intensive 7-month field campaign (part of the French-Mexican project MERCI-CO2) in the MCMA area during October 2020 to May 2021. One FTIR has been continuously operated since 2012 from an NDACC station (Altzomoni Atmospheric Observatory) located on a mountain top (3,985 m a.s.l), which is 60 km from Mexico City. This high-resolution IFS 120/5HR (spectral resolution < 0.02 cm-1) spectrometer performs regular NDACC and XCO2 TCCON-like measurements using alternate optical components and retrieval strategies but producing similar results. Two low-resolution portable EM27/SUN (spectral resolution < 0.5 cm-1) FTIR instruments are permanently operated at the university campus (UNAM) South of the city, and at a northern site (Vallejo) since 2016 and 2019, respectively. The other 4 EM27/SUN instruments were deployed as part of the MERCI-CO2 project. The measurement campaign was funded by the CONACyT-ANR project 290589 ‘Mexico City’s Regional Carbon Impacts’ (ANR-17-CE04-0013-01).