Transition to turbulence in the oceanic boundary layer beneath ice shelves

We use large-eddy simulations of the ocean beneath ice shelves to examine the transition to turbulence and the melt rate. The rectangular domain is bounded from above by the ice shelf base where a dynamic melt condition is imposed. An imposed far-field current provides a shear flow while the far-field temperature and salinity are restored to chosen values. For the majority of the simulations, the ice base is assumed to be horizontal, but in a series of additional runs the effect of small slopes is considered. We examine a range of far-field current strengths and temperatures to identify a fully turbulent regime and a relaminarising regime. The Obukov length scale, a comparison of the strength of shear flow turbulence to the buoyancy flux at the base of the ice, is successfully used to describe this transition to turbulence. We use parameters that are comparable to realistic Antarctic ice shelves to provide a real-world comparison.