Comparison of Satellite and Ground-Based Measurements of Tropospheric Ozone Columns in the Vicinity of St. Petersburg

Abstract

The monitoring of tropospheric ozone in world science has recently received considerable attention since ozone in the troposphere is both a greenhouse and a pollutant gas. It also plays an important role in various chemical and photochemical processes. Ground-based measurements can be used to assess the quality and to validate satellite measurements of the global ozone distribution. The time series of ozone tropospheric columns in the 0-8 km layer derived from spectral measurements of the IASI satellite instrument using two different algorithms (IASI_LATMOS and IASI_LISA), as well as from joint measurements by the IASI and GOME-2 instruments (IASI-GOME2) were compared to ground-based measurements using the Bruker IFS 125HR Fourier spectrometer at the NDACC St. Petersburg site for 2009–2021. IASI_LISA and IASI-GOME2 on average overestimate ground-based ozone measurements by 9.8 and 5.1%, respectively, while there is no bias between the IASI_LATMOS and FTIR data. The standard deviations of the differences between ground measurements and the IASI_LISA and IASI_LATMOS data do not exceed 12–13%; for the IASI-GOME2 data they are 24.5%. Ground-based and satellite measurements agree better in spring and summer. Ground-based and IASI_LATMOS demonstrate a statistically significant negative trend in the ozone columns in the 0–8 km layer in the vicinity of St. Petersburg for the period 2012–2021, amounting to –0.71 ± 0.35% per year and –0.60 ± 0.21% per year, respectively.