In the following we describe four key research issues that we will study within SHARP. Three research issues address relevant aspects of Theme 1 and deal with changes in stratospheric dynamics (with focus on the Brewer-Dobson circulation) and chemical composition (with focus on the evolution of stratospheric O₃ and H₂O). The fourth research topic will deal with the vertical radiative and dynamical coupling between stratosphere and troposphere and the impact of stratospheric changes on tropospheric climate and weather (Theme 2).

• The Brewer-Dobson Circulation (BDC)

• Ozone (OCF)

• Water Vapour (WV)

• Stratosphere–Troposphere Coupling (STC)