The Influence of Zonally Asymmetric Stratospheric Ozone Changes on the Arctic Polar Vortex Shift

Abstract

Recent studies have found a shift of the Arctic stratospheric polar vortex toward Siberia during late winter since 1980, intensifying the zonally asymmetric ozone (ZAO) depletion in the northern middle and high latitudes with a stronger total column ozone decline over Siberia compared with that above other regions at the same latitudes. Using observations and a climate model, this study shows that zonally asymmetric stratospheric ozone depletion gives a significant feedback on the position of the polar vortex and further favors the stratospheric polar vortex shift toward Siberia in February for the period 1980–99. The polar vortex shift is not significant in the experiment forced by zonal mean ozone fields. The February ZAO trend with a stronger ozone decline over Siberia causes a lower temperature over this region than over the other regions at the same latitudes, due to shortwave radiative cooling and dynamical cooling. The combined cooling effects induce an anomalous cyclonic flow over Siberia, corresponding to the polar vortex shift toward Siberia. In addition, the ZAO depletion also increases the meridional gradient of potential vorticity over Siberia, which is favorable for the upward propagation of planetary wave fluxes from the troposphere over this region. Increased horizontal divergence of planetary waves fluxes over the region 60°–75°N, 60°–90°E associated with ZAO changes accelerates the high-latitude zonal westerlies in the middle stratosphere, further enhancing the shift of the stratospheric polar vortex toward Siberia. After 2000, the ZAO trend in February is weaker and induces a smaller polar vortex shift than that in the period 1980–99.

Springtime arctic ozone depletion forces northern hemisphere climate anomalies

“…Many operational forecast and reanalysis systems as well as climate models neglect possible impacts of stratospheric ozone on surface climate by prescribing a diagnostic ozone forcing [22,23,24], thus ignoring ozone feedbacks. Furthermore, they typically use a zonally averaged ozone climatology, whereas a longitudinally resolved ozone forcing may better represent the climatology and trends of the Arctic polar vortex and surface climate, as idealized model experiments show [25,26,27]. However, the importance of the spatial structure during Arctic ozone depletion is still unclear.…”

Role of Stratospheric Processes in Climate Change: Advances and Challenges

“…Stratospheric chemical composition changes Atmospheric chemistry plays a critical role in modulating global climate. Climatic impacts of stratospheric ozone, which is both radiatively and chemically active, have been well documented in the literature (e.g., de F. Forster and Shine, 1997; Son et al, 2009Son et al, , 2010Hu et al, 2015;Nowack et al, 2015Nowack et al, , 2018Xie et al, 2016;Maleska et al, 2020;Zhang et al, 2020a;Friedel et al, 2022;Oh et al, 2022). Apart from ozone, ODSs, aerosols, water vapor, and GHGs in the stratosphere all have an impact on global climate through radiative or chemical processes and chemical-radiative-dynamic feedbacks.…”

“…As for the changes in SPV position, Zhang et al (2016) found that the Arctic SPV in February shifted towards Eurasia during 1980-2016. Moreover, notably, the extent of the polar vortex shift in the last decade (2010s) compared to the 1980s was smaller than before (Zhang et al, 2020a), suggesting that there is a decadal variability in the SPV position, which is related to the internal variability in the climate system (Seviour, 2017;Zhao et al, 2022). In addition, various climate variabilities could influence the SPV position (Huang et al, 2018;Zhang et al, 2019a).…”

“…It has been suggested that climate-ozone feedback may amplify the climatic impacts of stratospheric ozone, since changes in ozone could induce changes in atmospheric circulation and planetary wave propagation through radiative-dynamical feedbacks (Nathan and Cordero, 2007;Albers and Nathan, 2013;Hu et al, 2015). Ozone-induced changes in planetary wave propagation and breaking may act directly on the tropospheric climate through the "downward control" theory (Haynes et al, 1991) or cause convergence and divergence anomalies in the upper tropospheric eddy heat flux and eddy momentum flux (Zhang et al, 2020a), indirectly changing the meridional overturning circulations in the troposphere (Limpasuvan and Hartmann, 2000;Garfinkel, 2020, 2021b).…”

“…These climate responses are closely related to a strengthened SPV and a delayed break-up of the SPV, which result from a cooling of the SPV due to stratospheric ozone depletion. In addition, stratospheric ozone depletion may also affect the position of the Arctic SPV and favor a shift of the SPV towards Siberia (Zhang et al, 2020a).…”