The sensitivity of ice-shelf ocean boundary layer dynamics and ice-shelf melting to local conditions

Carolyn Branecky Begeman1, Xylar Asay-Davis2 and Luke Van Roekel1, (1)Los Alamos National Laboratory, Los Alamos, United States, (2)Los Alamos National Laboratory, Fluid Dynamics and Solid Mechanics Group, Los Alamos, NM, United States
The ice-shelf ocean boundary layer modulates oceanic heat and salt fluxes to the ice-shelf base. Laboratory experiments, direct numerical simulations and very high resolution large-eddy simulations have offered insights into the m-scale dynamics that control melting but the stratified turbulence dynamics at 100m-scale remain underexplored. We conducted novel large-eddy simulations at 100m-scale to bridge this knowledge gap. These simulations include dynamic ice-shelf melting, large-scale pressure gradients, Coriolis forces, and the buoyancy generated by a sloping ice-shelf base. We use sensitivity analyses to identify the relative importance of factors such as slope, far-field temperature and salinity, and pressure gradients on melt rates. We also compare boundary layer structure and the turbulent kinetic energy budget across this range of conditions. An adequate representation of this range of boundary layer dynamics in ocean models is necessary to accurately predict future ice-shelf melting. In light of our findings, we discuss the prospects for new parameterizations in ocean models that include ice-shelf cavities: a parameterization of vertical ocean mixing and a parameterization of ice-shelf melting.