Lead-induced convection: a laboratory perspective

The polar ice cap often cracks and forms long, narrow channels of open water which are known as leads. These openings play an important role in the heat budget and circulation of polar oceans. In the winter opening of a lead is associated with the onset of turbulent convection above and below the lead, because of the refreezing of surface water and rejection of heat into the atmosphere, respectively. Lead-induced convection is associated with a rich variety of fluid-dynamical phenomena, yet studying them in filed situations is not easy due to the unpredictability of their occurrence and short resident times. As such, laboratory experiments and numerical models can play a major role in lead-related studies. The purpose of this paper is to review the results of some previous laboratory experiments, which appear to be of importance in guiding and interpreting field experiments, and to present the results of some new laboratory experiments dealing with lead-induced motions.