EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Tropospheric ozone and precursors (HCHO and CO) from the NDACC FTIR ground-based network

Corinne Vigouroux1 and the FTIR data providers*
Corinne Vigouroux and the FTIR data providers
  • 1Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels, Belgium (
  • *A full list of authors appears at the end of the abstract

Ground-based FTIR (Fourier transform infrared) stations contributing to the Network for Detection of Atmospheric Composition Change (NDACC), deliver time-series of ozone and some of its precursors at more than 20 sites, starting from the 90’s for the oldest stations. In the context of the Tropospheric Ozone Assessment Report (TOAR-II), we will present the status of the ground-based FTIR tropospheric ozone, formaldehyde (HCHO), and carbon monoxide (CO) measurements.

From high-resolution solar absorption spectra, O3, HCHO and CO total columns are obtained with a precision of about 2%, 8%, and 1%, respectively. In addition, the pressure dependence of fully resolved absorption lines allows retrieving low vertical resolution profiles and thus deriving few independent partial columns. For O3, the degrees of freedom for signal (DOFS) are about 4.5, allowing O3 amounts to be retrieved in four independent altitude layers: one in the troposphere and three in the stratosphere up to about 45 km, with a precision of 5–6 % for each partial column. For HCHO, the DOFS are only of order 1.0-1.5, with a sensitivity mainly located in the troposphere where most of the HCHO lies. For CO, about 2 DOFS can be obtained, with one of them located in the troposphere.

We will show the variability and trends (when long time-series are available) of O3, HCHO, and CO tropospheric partial columns at many FTIR stations, covering a wide range of latitudes and pollution conditions. To derive the trends, we use a multiple linear regression model including seasonal cycles and dynamical proxies explaining the species’ variability such as, e.g., the tropopause height, the El Niño-Southern Oscillation (ENSO), or the Quasi-Biennial Oscillation (QBO).

FTIR data providers:

Carlos Aquino Bauer, Thomas Blumenstock, Martine De Mazière, Omaíra García, Michel Grutter, James Hannigan, Nicholas Jones, Rigel Kivi, Bavo Langerock, Eric Lutsch, Emmanuel Mahieu, Maria Makarova, Johan Mellqvist, Isamu Morino, Isao Murata, Tomoo Nagahama, Justus Notholt, Ivan Ortega, Mathias Palm, Markus Rettinger, Amelie Röhling, Dan Smale, Wolfgang Stremme, Kim Strong, Youwen Sun, Ralf Sussmann, Yao Té, Yana Virolainen, Pucai Wang, Tyler Wizenberg

How to cite: Vigouroux, C. and the FTIR data providers: Tropospheric ozone and precursors (HCHO and CO) from the NDACC FTIR ground-based network, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-11944,, 2023.