Role of Stratosphere-Troposphere Exchange of Ozone in the Earth System

The transport of ozone from the stratosphere to the troposphere is a key contributor to the tropospheric ozone budget. It is estimated that the stratosphere-to-troposphere flux of ozone leads to ~500 Tg of ozone transported into the troposphere each year, which is comparable to the net chemical production of ozone within the troposphere. Using simulations performed with the UKESM1 Earth system model we explore how transport of ozone from the stratosphere to the troposphere has changed over the recent past, and explore the drivers of these changes. Additionally, we calculate the contribution of ozone with a stratospheric origin to tropospheric ozone radiative forcing, and explore the impacts of STE on regional air quality.