Meltwater circulation and permeability of Arctic summer sea ice derived from hydrological field experiments

• Main Authors: Freitag, Johannes, Eicken, H.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2003
• Subjects: Arctic; Journal of Glaciology; Sea ice
• Online Access: https://epic.awi.de/id/eprint/4648/; https://epic.awi.de/id/eprint/4648/1/Fre2001b.pdf; https://hdl.handle.net/10013/epic.15219; https://hdl.handle.net/10013/epic.15219.d001

ABSTRACTPermeability and meltwater flow have been studied in sea ice in the Siberian and central Arctic during the summers of 1995 and 1996. A bail-test technique has been adapted to allow for measurements of in-situ permeability, found to range between 1011 and 108 m2. Permeability varied by about a factor of 2 between 1995 (above-normal melt rates) and 1996 (below-normal melt rates). Release of fluorescent tracers (Fluoresceine, Rhodamine) furthermore allowed the derivation of flow velocities and assessment of the relevant driving forces. Hydraulic gradients in rough ice and wind stress in ponded ice were found to be particularly important, driving meltwater over distances of several m day1. The mid- to late summer ice was found permeable enough to completely divert meltwater from the surface into the ice interior. It could be shown, however, that lower permeabilities of the upper ice layers as well as refreezing of meltwater are associated with significantly lower permeabilities, in particular during the early melt season, fostering development of surface melt ponds.