Brine Drainage and Convection in Young Sea Ice

• Main Author: Niedrauer,Terren Mark
• Other Authors: WASHINGTON UNIV SEATTLE DEPT OF OCEANOGRAPHY
• Format: Text
• Language: English
• Published: 1977
• Subjects: Snow; Ice and Permafrost; *SEA ICE; THERMODYNAMICS; TEST METHODS; DRAINAGE; DYES; CONVECTION(HEAT TRANSFER); CIRCULATION; SALT WATER; DESALINATION; Brine channels; Recirculation; WUNR307252; Ice; permafrost; Sea ice
• Online Access: http://www.dtic.mil/docs/citations/ADA043351; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA043351

In a series of experiments using a 1.6 mm thick freezing tank, thin sections of salt water ice were grown which exhibit the same drainage features as natural sea ice. The tank design permitted photographs to be taken, while thermocouples mounted in the tank walls recorded the temperature profiles within the ice. Convection was observed in both the skeleton layer and in the brine channels by the flow of dyed brine. Flow in the skeleton layer was cusp-like in appearance, consisting of narrow downflow regions separated by broad upflow regions. Several brine channels were usually present in the ice and convective overturning occurred in these channels. The convection caused temperature fluctuations of 0.5 C, which calculations show increase the vertical heat flux by 2%. The brine drainage channels, which were usually sloped 30 deg to 60 deg to the horizontal, always had isotherms tilted from 0 deg to 13 deg in the same direction. The brine channels move both horizontally and vertically through the ice by melting their lower walls and freezing on the upper walls. An analysis based on the heat flux due to brine channel convection shows that convection can drive these wall movements. Our observations suggest that most of the brine movement in the channels is caused by recirculation of water from below the ice. We also observed the formation of brine pockets from brine tubes. (Author)