Buoyancy fluxes and glacial melt rates at vertical ice-ocean interfaces
are commonly parameterized using theories derived for unbounded free
plumes. A Large Eddy Simulation is used to analyze the disparate
dynamics of free plumes and wall-bounded plumes; the distinctions
between the two are supported by recent theoretical and experimental
advances and demonstrate that unbounded plume theory does not adequately
represent plume/boundary layer dynamics at ice-ocean interfaces.
Modifications to parameterizations consistent with these simulations are
tested and compared to results from numerical and laboratory experiments
of meltwater plumes. These modifications include 50\%
weaker entrainment and a distinct plume-driven friction velocity in the
shear boundary layer up to 8 times greater than the externally-driven
friction velocity. Using these modifications leads to 40 times the
ambient melt rate predicted by commonly used parameterizations at
vertical glaciers faces, which is consistent (and necessary for
consistency) with observed melt rates at LeConte Glacier, Alaska.