Brine rejection leads to salt-fingers in seasonally ice-covered lakes

Abstract

Brine rejection can lead to salt-finger formation under lake ice. We performed a series of experiments to visualize these fingers. We believe that we are the first to do so in a freshwater system. While we detected salt-fingers in our camera recordings, the signal of these fingers is nearly absent in the temperature record. Further, we estimate that the brine is often distributed evenly with depth. Comparing the salt fluxes in our experiments with estimated global averages, we argue that salt-fingers form in most seasonally icecovered lakes.

Laboratory Experiments on Ice Melting: A Need for Understanding Dynamics at the Ice-Water Interface

“…Subsequent wave-tank experiments presented in [150] further explored the formation of both frazil and pancake ice along with their structural properties. They also considered brine expulsion during ice formation (e.g., [38,151]). Laboratory experiments conducted by [152] furthered this by measuring ice thickness and temperature profiles during grease ice and pancake ice formation in response to cold air temperatures (−8 to −10 °C) adjacent to saltwater in a wave tank.…”

“…Several studies exploring ice solidification, including the impact of convective currents on ice formation [33,34], aqueous salt solutions solidified from above [35], turbulent measurements during ice growth [36], ice formation in a differentially heated cavity [37], and formations on lake ice from brine rejection [38] (in review) have been conducted, mostly with applications for sea ice growth. In addition, there are several experiments exploring melting of ice in air to explore, for example, hailstones (i.e., ice spheres) in an air stream [39], ice cubes in air flows at a wide range of temperatures [40], and ice in rectangular, cylindrical and conical forms in air of varying velocities [41].…”