On the determination and simulation of seawater freezing point temperature under high pressure

Abstract

At present, it is believed that the freezing point temperature of seawater is a function of salinity and pressure, and the freezing point is a key parameter in a coupled air-sea-ice system. Generally, empirical formulas or methods are used to calculate the freezing point of seawater. Especially in high-pressure situations, e.g., under a thick ice sheet or ice shelf, the pressure term must be taken into account in the determination of seawater freezing point temperature. This study summarized various methods that have been used to calculate seawater freezing point with high pressure. The methods that were employed in two ocean-ice models were also assessed. We identified the disadvantages of these methods used in these two models and addressed the corresponding uncertainties of the freezing point temperature formulas. This study provides useful information on the calculation of the freezing point temperature in numerical modeling and indicates a need to investigate the sensitivity of numerical simulations to the uncertainties in the freezing point temperature in future.