Heat of Freezing and Melting of Sea Ice

摘要

Computations are presented which show that the latent heat of freezing ice in equilibrium with sea water is less than that associated with freezing pure water at 0C. The difference is due primarily to a temperature effect that is opposed to some extent by the effect of dissolved substances in the brine. The difference probably amounts to about 7 cal/gm of ice for a brine of about 150 o/oo slinity, freezing at -8C. When the effect of this difference in the total heat required to raise the temperature and melt sea ice is computed by Schwerdtfeger's method, it is found to be of the order of 0.5 cal/gm of sea ice for an overall ice salinity of 8 o/oo and an initial temperature of -8C. The differences are small but significant and until true values are established, published values of heats of freezing and melting and specific heats of sea ice should be used with discretion. (Author)