Heat and salt transfer in subglacial plumes rising along a vertical ice face

Our current understanding of the small-scale fluid processes occurring in the glacier-ocean boundary layer is incomplete, and so parameterizations used in ice-ocean modeling are largely borrowed from the classic literature of heat transfer in engineered systems that do not represent glaciological conditions. The result is large departures between model predictions and observations of ocean melting of glaciers, which consequently leads to large uncertainties in projections of future sea level rise, particularly from Antarctica.

In this poster, we will present our laboratory results of heat and salt transfer across the ice-ocean interface formed between a subglacial plume and an initially smooth vertical ice face, a commonly found configuration in Greenlandic fjords. The laboratory experiments were done in a purpose-built water tank, inside a climate-controlled cold room and we simultaneously measured the temperature, salinity, and fluid velocity of subglacial plumes at high (~mm scale) spatiotemporal resolutions under realistic field conditions, using state-of-the-art particle image velocimetry (PIV) and laser-induced fluorescence (LIF) techniques for measurements. These experiments allow us to systematically re-examine the assumptions and simplifications made in existing melt-rate models, with the goal of deriving a revised and complete theory of melt at the ice-ocean interface.