Surface and tropospheric ozone trends in the Southern Hemisphere since 1990: possible linkages to poleward expansion of the Hadley circulation

Exploring 2016–2017 surface ozone pollution over China: source contributions and meteorological influences

“…The model includes a detailed mechanism of tropospheric HO x -NO x -VOC-ozone-halogen-aerosol chemistry (Wang et al, 1998;Bey et al, 2001;Park et al, 2004;Mao et al, 2013). The chemical kinetics are obtained from the Jet Propulsion Laboratory (JPL) and International Union of Pure and Applied Chemistry (IUPAC) (Sander et al, 2011;IU-PAC, 2013).…”

Detecting the fingerprints of observed climate change on surface ozone variability

“…A new study by Lu et al [8], appearing in Science Bulletin, explores a new aspect of the impact of climate change on surface ozone trends. To date, studies of the impacts of climate change on tropospheric ozone have focused on future scenarios in a much warmer world, as relatively strong temperature increases are required for the chemistry-climate models to detect an impact on ozone trends.…”

“…To date, studies of the impacts of climate change on tropospheric ozone have focused on future scenarios in a much warmer world, as relatively strong temperature increases are required for the chemistry-climate models to detect an impact on ozone trends. However, Lu et al [8] argue that there is now evidence that present-day levels of climate change have already contributed to a widening of the Hadley circulation [9], which has impacted surface ozone levels. Given the difficulty of distinguishing between the impacts of anthropogenic emissions, climate variability and climate change on long-term ozone trends, the authors focused their study on remote sites in the Southern Hemisphere, which experience far less impact from anthropogenic emissions than similar sites in the Northern Hemisphere.…”

“…This widening is partly attributable to anthropogenic climate change. Lu et al [8] used a global chemical transport model to explore the impact of Hadley circulation widening on tropospheric ozone across the Southern Hemisphere. They learned that the observed ozone increase cannot be explained by increases of anthropogenic emissions of ozone precursors.…”

“…Lu et al [8] have made the case that observed and modeled changes of the Southern Hemisphere circulation can be partly attributed to anthropogenic climate change, and these circulation changes can affect long-term ozone trends. Looking forward, future work could explore the impacts of climate change on other aspects of ozone production and loss.…”