Distinguishing the impacts of ozone and ozone depleting substances on the recent increase in Antarctic surface mass balance

• Main Authors: Chemke, Rei, Previdi, Michael, England, Mark R., Polvani, Lorenzo M.
• Format: Text
• Language: English
• Published: 2020
• Subjects: Antarctic; Austral; The Antarctic; Antarc*
• Online Access: https://doi.org/10.5194/tc-2020-157; https://tc.copernicus.org/preprints/tc-2020-157/

The Antarctic surface mass balance (SMB) has global climatic impacts through its effects on global sea-level rise. The forced increase in Antarctic SMB over the second half of the 20th century was argued to stem from multiple forcing agents, including ozone and ozone-depleting substances. Here we use ensembles of fixed-forcing model simulations to quantify and contrast the contributions of stratospheric ozone, tropospheric ozone and ozone-depleting substances (ODS) to increases in the Antarctic SMB. We show that ODS and stratospheric ozone make comparable contributions, and together account for 44 % of the increase in the annual mean Antarctic SMB over the second half of the 20th century. In contrast, tropospheric ozone has an insignificant impact on the SMB increase. A large portion of the annual mean SMB increase occurs during Austral summer, when stratospheric ozone is found to account for 63 % of the increase. Furthermore, we demonstrate that stratospheric ozone increases the SMB by enhancing the meridional mean and eddy flows towards the continent, thus converging more water vapor over the Antarctic.