The cryosphere is an integral and under-constrained component of the Earth's climate system. For example, the dynamics of the Greenland and Antarctic ice sheets control a significant fraction of sea level rise, whilst the evolving sea-ice cover in the polar oceans modulates the fluxes of heat, salt, and climatically active gases at the atmosphere-ocean interface. The Ice and Fluid Dynamics group uses theoretical and numerical modelling approaches, constrained by experiment, to study the physical processes that control ice-ocean interaction and the dynamics of other geophysical fluid flows. Examples of potential DPhil topics include modelling multiphase flows and greenhouse gas transfer through porous sea ice, or modelling the dynamics of buoyant meltwater flows and their impact on the melting of marine-terminating ice sheets. I would also be delighted to discuss alternative projects in geophysical and environmental fluid dynamics that are of interest to potential students.