Topic outline

  • General

    • Dynamics of the stratosphere and the role of aviation

      The structure of the stratosphere is very stable and movement of air between the troposphere and stratosphere is very slow compared to the movement of air within the troposphere itself.  However, this small air exchange is important and we look at its implications in this unit.

      The second part of this unit looks at emissions from aircraft.  Aeroplanes fly at altitudes ranging from those in the upper troposphere to the lower stratosphere.  This region is very sensitive to emissions of any kind and pollution from growing air traffic is, therefore, very important to our climate.

      contrails from aviation

      1. Contrails from aviation.
      © freefoto.com

    • Stratospheric ozone, chlorofluorocarbons, the ozone hole and its impact

      Although ozone has been the subject of research since the 19th Century, it wasn't until the discovery of the Antarctic ozone hole that this research intensified.  This unit looks at the history of ozone research, looking primarily at the reactions which lead to ozone depletion.  We concentrate on the chlorofluorocarbons (CFC's), since these are the most important ozone destroyers, looking at their characteristics and their modern replacements.

      We also look at the differing roles of ozone in the stratosphere where it protects us from high intensity ultra-violet radiation from the Sun and in the troposphere where ozone is an important greenhouse gas, contributing to global warming.

      Scientists assume that the ozone hole will slowly close over the next 50 years.  Increasing cooling in the stratosphere may, however, slow down the recovery of the ozone layer.  In this unit we investigate what is going on.

      Antarctic ozone hole

      1. Ozone hole
      © NASA GSFC 2003