ABSTRACT
The upper atmosphere of the Earth is invisible to the vast majority of the planet's inhabitants. It is grouped into three themes: stratospheric clouds, the ozone hole and storm tracks; noctilucent clouds, meteor smoke and geo-engineering; solar variability, relativistic electrons and climate. Energy from the Sun is the primary energy source for the Earth's climate system and, ultimately, for all life on Earth. In the natural state, ozone is produced mainly over the tropics and is transported to the Polar Regions by global wind systems in the upper atmosphere. The main source of ozone in the Earth's atmosphere is the action of solar ultraviolet light on oxygen in the stratosphere and mesosphere. Stratospheric air enters the troposphere primarily in 'tropopause fold' structures, which are associated with the storm tracks around the Polar Regions. The changes in Southern Annular modes have been convincingly attributed primarily to the cooling of the polar stratosphere caused by the Antarctic ozone hole.
