ozone layer

The layer between 10 and 50 km that contains most atmospheric ozone, with the greatest concentration at altitudes of 20–25 km. It absorbs most of the energy from ultraviolet radiation from the Sun, and thus acts as a protective shield for life on the Earth's surface. The energy absorbed causes the rise in temperature with height that occurs in the stratosphere. It has recently been established that solar proton events (see solar wind) may cause transient decreases in ozone concentrations by c.10 per cent and a simultaneous increase in concentration in the upper troposphere.