Articles | Volume 10, issue 7
Research article
27 Jul 2017
Research article |  | 27 Jul 2017

Ground-based remote sensing of O3 by high- and medium-resolution FTIR spectrometers over the Mexico City basin

Eddy F. Plaza-Medina, Wolfgang Stremme, Alejandro Bezanilla, Michel Grutter, Matthias Schneider, Frank Hase, and Thomas Blumenstock

Abstract. We present atmospheric ozone (O3) profiles measured over central Mexico between November 2012 and February 2014 from two different ground-based FTIR (Fourier transform infrared) solar absorption experiments. The first instrument offers very high-resolution spectra and contributes to NDACC (Network for the Detection of Atmospheric Composition Change). It is located at a mountain observatory about 1700 m above the Mexico City basin. The second instrument has a medium spectral resolution and is located inside Mexico City at a horizontal distance of about 60 km from the mountain observatory. It is documented that the retrieval with the high- and medium-resolution experiments provides O3 variations for four and three independent atmospheric altitude ranges, respectively, and the theoretically estimated errors of these profile data are mostly within 10 %. The good quality of the data is empirically demonstrated above the tropopause by intercomparing the two FTIR O3 data, and for the boundary layer by comparing the Mexico City FTIR O3 data with in situ O3 surface data. Furthermore, we develop a combined boundary layer O3 remote sensing product that uses the retrieval results of both FTIR experiments, and we use theoretical and empirical evaluations to document the improvements that can be achieved by such a combination.

Short summary
We present data and error estimations of O3 profiles retrieved from spectra measured by a medium- and a high-resolution FTIR spectrometer (located at 2260 m and 3985 m a.s.l.). Above the tropopause both data sets agree well and in accordance with the estimated errors. We introduce a product that combines the two FTIR retrieval results, and a comparison to Mexico City in situ data indicates that the combined product is able to capture the highly varying boundary layer O3 concentrations.