On a differentially heated saltwater-ice system

A previous theoretical study by Welander (1977) on a freshwater-ice oscillator is extended to the saltwater case. The system comprises a deep high-salinity, warm water reservoir (fixed temperature and salinity), and a shallow constant-depth mixed layer with temperature, salinity, and ice thickness varying in time. This layer is cooled by contact with overlaying air kept at a fixed, subzero temperature. The main new feature is the variation of the heat flux through the water interface with the stratification. This variation causes two new phenomena of interest: (a) “false” thermal adjustments to existing ice-covered steady states, and (b) multi-periodic self-sustained oscillations including both ice-covered and ice-free regimes. The usefulness of basic model studies of this type in connection with climate research is pointed out.