The role of the Mt. Merapi eruption in the 2011 Arctic ozone depletion

- Arctic ozone loss in 2011 was due to the spring strengthening of the polar vortex.
- Tropical heating after the Mt. Merapi eruption intensified the Arctic polar vortex.
- Tropical volcanic eruptions in autumn-winter period can lead to Arctic ozone loss.

One of the strongest ozone depletion events in the Arctic stratosphere was observed in March 2011 due to the strengthening of the polar vortex in February 2011. Earlier, in November 2010, the eruption of Mt. Merapi volcano (Java, Indonesia) with a maximum plume altitude of 18.3 km was recorded. The effect of aerosol heating in the tropical lower stratosphere after the Mt. Merapi eruption on the Arctic polar vortex strengthening in winter-spring 2011 is examined. Based on the ERA-Interim reanalysis temperature data, we show that significant aerosol heating in the lower tropical stratosphere was observed in February-March 2011 and could lead to an increase in the stratospheric equator-to-pole temperature gradient resulting in an enhanced Arctic polar vortex. We also analyze the correlation between large tropical volcanic eruptions occurring in autumn-winter periods and Arctic ozone depletion events observed in the following winter-spring periods.