Relative role of short interfacial fingers and long internally driven streamers in convective flows below growing sea ice

Abstract

As sea ice grows from sea water, salt initially dissolved in the liquid is rejected from the solid. Buoyancy-driven flows develop under the ice layer in two ways: 1) interfacial boundary layer convection resulting in small-scale fingers and 2) internal convection originating from brine drainage channels inside the ice, flushing out longer-scale convective streamers. We study these dynamics experimentally by freezing salt water from above in a quasi-2D Hele-Shaw cell, observing with Schlieren and direct imaging systems. Interfacial fingers turn out more significant as a salt-transport pathway than previously thought, persisting throughout ice growth, whereas streamers show on-off behavior.