Zhang, J., Tian, W., Xie, F., Chipperfield, M. P., Feng, W., Son, S.-W., Abraham, N. L., Archibald, A. T., Bekki, S., Butchart, N., Deushi, M., Dhomse, S., Han, Y., Jöckel, P., Kinnison, D., Kirner, O., Michou, M., Morgenstern, O., O’Connor, F. M., Pitari, G., Plummer, D. A., Revell, L. E., Rozanov, E., Visioni, D., Wang, W., and Zeng, G.

Nature Communications, 9, 206, doi: 10.1038/s41467-017-02565-2

The Montreal Protocol has succeeded in limiting major ozone-depleting substance emissions,
and consequently stratospheric ozone concentrations are expected to recover this century.
However, there is a large uncertainty in the rate of regional ozone recovery in the Northern
Hemisphere. Here we identify a Eurasia-North America dipole mode in the total column
ozone over the Northern Hemisphere, showing negative and positive total column ozone
anomaly centres over Eurasia and North America, respectively. The positive trend of this
mode explains an enhanced total column ozone decline over the Eurasian continent in the
past three decades, which is closely related to the polar vortex shift towards Eurasia. Multiple
chemistry-climate-model simulations indicate that the positive Eurasia-North America dipole
trend in late winter is likely to continue in the near future. Our findings suggest that the
anticipated ozone recovery in late winter will be sensitive not only to the ozone-depleting
substance decline but also to the polar vortex changes, and could be substantially delayed in
some regions of the Northern Hemisphere extratropics.