Tropical Stratospheric Circulation and Ozone Coupled to Pacific Multi-Decadal Variability

Iglesias Suarez, Fernando and Wild, Oliver and Kinnison, Douglas E. and Garcia, Rolando and Marsh, Dan and Lamarque, Jean-Francois and Ryan, Edmund and Davis, Sean and Eichinger, Roland and Saiz-Lopez, Alfonso and Young, Paul (2021) Tropical Stratospheric Circulation and Ozone Coupled to Pacific Multi-Decadal Variability. Geophysical Research Letters, 48 (11): e2020GL092. ISSN 0094-8276

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Abstract

Observational and modeling evidence suggest a recent acceleration of the stratospheric Brewer-Dobson circulation (BDC), driven by climate change and stratospheric ozone depletion. However, slowly varying natural variability can compromise our ability to detect such forced changes over the relatively short observational record. Using observations and chemistry-climate model simulations, we demonstrate a link between multi-decadal variability in the strength of the BDC and the Interdecadal Pacific Oscillation (IPO), with knock-on impacts for composition in the stratosphere. After accounting for the IPO-like variability in the BDC, the modeled trend is approximately 7%–10% dec−1 over 1979–2010. Furthermore, we find that sea surface temperatures explain up to 50% of the simulated decadal variability in tropical mid-stratospheric ozone. Our findings demonstrate strong links between low-frequency variability in the oceans, troposphere and stratosphere, as well as their potential importance in detecting structural changes in the BDC and future ozone recovery.