Tropospheric ozone global and regional distributions and trends from IASI

Tropospheric ozone (O3) is an important short-lived climate forcer and a critical secondary air pollutant, detrimental to human health and ecosystems. It is the dominant source of the hydroxyl radical OH that is highly reactive with organic and inorganic compounds. Global tropospheric O3 concentrations have been rising considerably since the pre-industrial period as a result of the increase in the anthropogenic emissions of O3 precursors. Assessing the long-term tropospheric O3 trends is critical for understanding the impact of human activity and climate change on atmospheric chemistry. Since 2007, the IASI (Infrared Atmospheric Sounding Interferometer) instruments have been embarked on board the polar-orbiting meteorological satellites Metop-A, -B and -C. The European Organization for the Exploitation of Meteorological Satellites (EUTMETSAT) is currently reprocessing the IASI O3 dataset providing a homogeneous record of O3. In this study, we aim to assess tropospheric ozone distributions and trends on the global and regional scales for the period 2008-2023 using the homogeneous IASI O3 dataset. Comparisons of the IASI data with the Cross-track Infrared Sounder (CrIS) satellite observations are also performed.