Sarah Shallcross

Sarah Shallcross


The role of injection height, volume of SO2 and ash in the global dispersion of the enhanced stratospheric aerosol cloud from the 1991 Mount Pinatubo eruption.

Funded: ECMWF - CAMS43 Project and University of Leeds

Volcanic eruptions have the potential to inject huge quantities of sulphur dioxide and ash into the stratosphere. Chemical reactions in the atmosphere convert sulphur dioxide into highly-scattering sulphuric acid aerosols. The scattering effects of these aerosols causes short wave radiation to be scattered back to space, away from the surface, creating a cooling effect. Following large volcanic eruptions this cooling effect has been particularly prominent, such as 'the year without summer' caused following the 1815 Mount Tambora eruption.

The last great eruption was the Pinatubo eruption in 1991, which, due to limited observations at the time has varying values for radiative perturbation. This is where models have been used, to try and recreate what observations are available and, in turn, understand the processes occurring at the time of these eruptions to gain a better understanding of their radiative forcing.

This project focuses on using the UM-UKCA model in conjunction with ground-based lidar observations available at the time of the Pinatubo eruption to work on the issue of global dispersion and the role of ash.

Research groups and institutes

  • Atmospheric Chemistry and Aerosols
  • Institute for Climate and Atmospheric Science