Tropospheric ozone affects air quality and climate, being a pollutant and a greenhouse gas. We analyze satellite data of tropospheric ozone columns obtained by combining two types of observations: one providing stratospheric and the other total ozone. We compare common climatological features and study the influence of the tropopause (troposphere to stratosphere boundary) on the results. We also examine trends over the last 20 years and compare satellite data with ozonesondes to identify drifts.

We use observational data to track a mass of mesospheric air which descends into the Antarctic polar vortex each spring. The altitude of the air mass at the end of October is used to create a new diagnostic metric. The metric captures the dynamical conditions of the vortex and can be used to estimate the amount of poleward ozone transport in October. When used as a proxy for October polar total column ozone, the metric explains the majority (63%) of the observed variance from 2004–2024.

This study presents the CLCD (CHORA Local Cloud Decision) algorithm for retrieving near-global tropospheric ozone using TROPOMI data. The approach refines the Convective Cloud Differential method by using a local cloud reference sector to minimize errors from stratospheric ozone variability, particularly in mid-latitudes. Validation against ground-based data shows good accuracy, highlighting its potential for improving air quality monitoring and supporting current and future satellite missions.

CHORA, an advanced cloud convective differential technique, enhances the accuracy of tropospheric-ozone retrievals. Unlike the traditional Pacific cloud reference sector scheme, CHORA introduces a local-cloud reference sector and an alternative approach (CLCT) for precision. Analysing monthly averaged TROPOMI data from 2018 to 2022 and validating with SHADOZ ozonesonde data, CLCT outperforms other methods and so is the preferred choice, especially in future geostationary satellite missions.

Cyclones strongly influence weather predictability but still cannot be fully characterised in the Arctic because of the sparse coverage of meteorological measurements. A potential approach to compensate for this is the use of satellite measurements of ozone, because cyclones impact the tropopause and therefore also ozone. In this study we used this connection to investigate the correlation between ozone and the tropopause in the Arctic and to identify cyclones with satellite ozone observations.