Abstract

Ice shelves, the floating extensions of ice sheets, play an important role in sea level rise by buttressing the grounded ice. Ice shelf collapse and the loss of this buttressing support can lead to increase discharge of grounded ice, evidenced by the collapse of the Larsen B ice shelf in 2002. The fate of Antarctic ice shelves is a significant source of uncertainty in global projections of sea level rise.

Small-scale turbulence in the ice shelf/ocean boundary layer beneath ice shelves transports warm waters towards the ice, thereby influencing melting. Parameterizations of mixing and melting in the ice shelf/ocean boundary layer are relatively crude, but the physics at play are intricate and fascinating. Beneath sloping ice shelves, the relatively buoyant melt water flows up the slope and is deflected by the Coriolis force. At the same time, stratification associated with fresh meltwater suppresses turbulence and mixing.

I will discuss previous and ongoing work combining simulations and observations of turbulence and mixing in ice shelf/ocean boundary layers. The work spans a range of conditions from cold water ice shelves where tides dominate the melting signal, to warm water ice shelves where buoyancy-driven currents and extreme ice topography result in very complicated flow. In between I will discuss the role of diffusion when relatively flat ice shelves are exposed to warm waters.