Observations and Theoretical Calculations of 11-Year Cyclic Variations in Lower-Stratospheric Ozone Depletion and Cooling

TL;DR

This study combines observations and CRE model calculations to reveal 11-year cyclic variations in lower-stratospheric ozone and temperature, demonstrating cosmic rays' significant role in ozone depletion and climate trends, with implications for future ozone recovery.

Contribution

It provides the first parameter-free CRE model calculations that accurately match observed ozone and temperature variations, highlighting cosmic rays' influence on ozone depletion.

Findings

11-year cyclic ozone and temperature variations observed over Antarctica and mid-latitudes.

CRE model accurately reproduces observed ozone profiles and trends.

Future ozone and temperature trends are strongly affected by cosmic-ray flux variations.

Abstract

Observations and quantitative understanding of spatio-temporary variations in lower-stratospheric ozone and temperature can provide fingerprints for the mechanisms of ozone depletion and play an important role in testing the impact of non-halogen greenhouse gases on the ozone layer in climate models. Here we report from ground-based ozonesonde and satellite-based measurements since the 1960s and 1979 respectively that both lower-stratospheric ozone and temperature display pronounced 11-year cyclic variations over Antarctica and mid-latitudes, while no apparent cyclic variations over the tropics. These observations were unexpected from the chemistry-climate models (CCMs) but predicted by the cosmic-ray-driven electron-induced-reaction (CRE) model of ozone depletion. Remarkably, no-parameter CRE theoretical calculations give the ozone loss vertical profile in perfect agreement with observations at the Antarctic Syowa station and excellently reproduce time-series variations of both lower-stratospheric ozone and temperature in all global regions. Furthermore, the large lower-stratospheric ozone depletion over the tropics in the 1980s and 1990s is also reproduced by CRE calculations. Moreover, CRE calculations exhibit complex phenomena in future trends of lower-stratospheric ozone and temperature, which are strongly affected by the future trends of cosmic-ray fluxes. The latter might even lead to almost no recovery of the ozone hole over Antarctica and no returning to the 1980 level over the tropics by 2100. The results also strikingly demonstrate that both lower-stratospheric ozone and temperature are controlled by cosmic rays and ozone-depleting substances only. This study greatly improves quantitative understanding of ozone depletion and climate in the global lower stratosphere and offers new predictions on future trends.