The Formation of Brine Drainage Features in Young Sea Ice

• Published in: Journal of Glaciology
• Main Authors: Ingolf Eide, Lars, Martin, Seelye
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1975
• Subjects: Earth-Surface Processes; Ice Sheet; Journal of Glaciology; Sea ice
• Online Access: http://dx.doi.org/10.1017/s0022143000013460; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000013460

Laboratory experiments on the growth of sea ice in a very thin plastic tank filled with salt water, cooled from above and insulated with thermopane, clearly show the formation and development of brine drainage channels. The sea-water freezing cell is 0.3 cm thick by 35 cm wide by 50 cm deep; the thermopane insulation permits the ice interior to be photographed. Experimentally, we observe that vertical channels with diameters of 1 to 3 mm and associated smaller feeder channels extend throughout the ice sheet. Close examination of the brine channels show that their diameter at the ice-water interface is much narrower than higher up in the ice, so that the channel has a “neck” at the interface. Further, oscillations occur in the brine channels, in that brine flows out of the channel followed by a flow of sea-water up into the channel. Theoretically, a qualitative theory based on the difference in pressure head between the brine inside the ice and the sea-water provides a consistent explanation for the formation of the channels, and the onset of a convective instability explains the existence of the neck. Finally, an analysis based on the presence of the brine-channel neck provides an explanation for the observed oscillations.