A Laboratory Study of Heat Flux Through Coastal Polynyas During Frazil-Ice Production

Shuki Ushio, Masaaki Wakatsuchi
1990 Annals of Glaciology  
We carried out laboratory experiments with a test tank in a cold room to estimate heat flux through coastal polynyas, which have great effects on climate in the polar regions. The estimation of heat flux from water to air was made with measurements of cooling rate of water temperature and of the rate of ice production as a function of wind speed and water salinity. Both rates increased with increasing wind speed and water salinity. The major factor that governs heat flux is the size of the open
more » ... he size of the open water area. In an open water area continuously maintained by a strong cold wind, rapid production of frazil ice and its downwind transport occur simultaneously; so the open water serves as an efficient ice factory. In the case of NaCl solution, supercooled water with salinity greater than 23.1‰ is denser than water at its freezing point. Therefore, the formation and sinking of the supercooled water occur in the persistent open water; this results in great lowering of water temperature and underwater-ice production. Strong wind and high salinity enhance the supercooling effect.
doi:10.1017/s0260305500008788 fatcat:gui67esbunaa3dmd7tjne4kv54