HR: 0800h
AN: C41C-0206    [Abstracts]
TI: Porosity-Permeability-Salinity Relationships in First-Year Arctic Sea Ice
AU: * Eicken, H
EM: hajo.eicken@gi.alaska.edu
AF: Geophysical Institute, University of Alaska Fairbanks, P.O. Box 757320, Fairbanks, AK 99775-7320 United States
AU: Cole, D M
EM: dmcole@crrel.usace.army.mil
AF: Cold Regions Research and Engineering Laboratory, 72 Lyme Rd., Hanover, NH 03775 United States
AU: Shapiro, L H
EM: lews@gi.alaska.edu
AF: Geophysical Institute, University of Alaska Fairbanks, P.O. Box 757320, Fairbanks, AK 99775-7320 United States
AB: Despite the importance of sea-ice permeability in controlling mass and heat fluxes through the ice cover, few measurements of ice permeability (as a function of porosity) have been completed to date. Here, we report on results of ice permeability measurements based on in-situ borehole slug tests. Data were obtained from different depth levels of homogeneous Arctic first-year landfast ice near Barrow, Alaska throughout the ice seasons of 1999 to 2001. Thermistor arrays frozen into the ice and analysis of ice cores and large slabs cut through the entire ice thickness provided anicllary data on sea ice thermal, salinity and microstructural evolution. Permeabilities ranged between 3 x 10$^{-13}$ m$^{2}$ (brine volume fraction 0.033) and 4 x 10 $^{-10}$ m$^{2}$ (brine volume fraction 0.24), with a sharp increase towards the base of the ice cover. Permeability-porosity relationships appear to fall into two regimes: (1) a two orders of magnitude increase in permeability for the 0.03 to 0.09 brine volume fraction interval, and (2) a one order of magnitude increase for brine volume fractions $>$0.09. However, interpretation of these regimes is hampered by significant scatter in the data due to measurement errors and natural variability. Examination of pore micro-/macrostructure and time series of vertical salinity profiles can provide additional insights into the co-evolution of ice permeability and porosity.
DE: 4540 Ice mechanics and air/sea/ice exchange processes
DE: 1827 Glaciology (1863)
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting